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Delivery of Doosan Excavator Slewing Bearing to South America

May 12, 2026/in LDB Company News /by LDB Bearing

In November 2022, our company successfully delivered a Four-Point Contact Ball Slewing Bearing for a Doosan excavator to a client in South America. The customer needed a high-performance slewing ring to support demanding applications such as earthmoving, construction, and infrastructure development. We supplied a four-point contact ball slewing bearing, which features a single row of steel balls with four contact points between each ball and the raceway. This design allows the bearing to withstand axial loads, radial loads, and tilting moments simultaneously.

Manufactured from high-strength 42CrMo and 50Mn steel, this bearing offers a compact structure, light weight, and high static load capacity ranging from 129kN to 3,410kN. LDB provides outer diameters from 200mm to 10,000mm, inner diameters from 100mm to 8,000mm, and ball diameters from 30mm to 75mm to meet various excavator models. After rigorous factory testing including dimensional inspection, hardness testing (raceway quenching hardness HRC 55-62), and gear accuracy verification, we shipped the bearing in November 2022. We used anti-corrosion treatment and export-standard fumigation-free wooden boxes for secure ocean freight to South America.

The customer confirmed successful installation and reported that the four-point contact ball slewing bearing delivered smooth rotation, low noise, and stable performance under daily operating conditions. LDB provides a 12-month warranty, 10-30 day delivery, and flexible gear options including internal gear, external gear, or non-gear configurations. For split ring designs, we pre-connect the two split rings with bolts before shipment to simplify on-site installation. This case further demonstrates our capability to serve Doosan excavator users across South America with custom-engineered slewing solutions.

What Are Four-Point Contact Ball Slewing Bearings?

A four-point contact ball slewing bearing is a specialized heavy-load bearing that enables smooth rotation in large machinery. The main components include an inner ring, an outer ring, a single row of steel balls, a cage or spacer, and a sealing device. Manufacturers offer both integral and split designs for the inner and outer rings. An integral ring provides excellent rigidity, while a split ring gives you more flexibility during adjustment. For split designs, LDB uses bolts to fasten the two split rings together before shipping.

Most of these bearings come with a cage or spacer. However, when your application demands extra load capacity, a full-ball design works better. Keep in mind that full-ball bearings carry more load but also create higher friction. This friction may lead to surface scratches on the steel balls over time. You can order four-point contact ball slewing bearings with no gear, external gear, or internal gear teeth. All configurations deliver impressive static load capacity for tough working conditions.

How Does a Four-Point Contact Ball Slewing Bearing Work?

The operating principle of this bearing type centers on the interaction between steel balls and arc-shaped raceways. Each steel ball touches the raceway at four distinct points—two points on the inner ring and two points on the outer ring. This clever geometry allows a single bearing to manage axial loads coming from either direction, radial loads, and tilting moments all at once.

When heavy forces enter the bearing, the steel balls distribute those forces across the four contact points. The load distribution shifts depending on the force direction. Pure vertical loads engage all four contact points evenly. Combined loads cause some points to carry more force while others relax. This dynamic behavior explains why one bearing can replace multiple bearing types in complex applications. A pinion gear drives the system by engaging the internal or external gear teeth on the bearing ring. As the pinion turns, the bearing ring rotates, and your equipment moves smoothly with very little friction.

Structural Features of Four-Point Contact Ball Slewing Bearings

These bearings stand out because of their smart structural design. The single-row configuration uses two seat rings, which keeps the whole assembly compact and surprisingly lightweight. The steel balls contact the arc raceway at four points, giving the bearing the ability to handle axial forces, radial forces, and tilting moments all in one unit.

LDB builds these bearings with outer diameters between 300mm and 10,000mm. Ball diameters range from 30mm to 75mm, while rated loads fall between 129kN and 3,410kN. We choose 42CrMo and 50Mn steel for their outstanding strength and resistance to wear. The seals use nitrile rubber, a material that keeps contaminants out and lubrication in. Heat treatment follows strict standards: normalizing hardness reaches 187HB-241HB, quenching and tempering delivers 229HB-269HB, and raceway quenching hits HRC 55-62. Every LDB bearing comes with a 12-month warranty and ships within 10 to 30 days.

Main Configuration Types of Four-Point Contact Spherical Slewing Bearings

You have three main choices when it comes to gear configuration:

Non-Gear Type (No Tooth)
This version has no gear teeth on either ring. It works perfectly when your drive system operates independently of the bearing itself.

External Gear Type (External Tooth)
The outer ring carries gear teeth on its outside surface. A pinion gear engages these teeth from the exterior. This setup fits applications where the drive motor sits outside the rotating part.

Internal Gear Type (Internal Tooth)
The inner ring holds gear teeth on its inside surface. The pinion mounts within the bearing ring. This arrangement gives you a cleaner look and adds protection to the gear mechanism.

LDB offers all three types, and we can match the gear configuration precisely to your mechanical layout. You also get to choose between integral and split ring structures. All options feature four-point contact with your selected tooth configuration.

Core Advantages of Four-Point Contact Spherical Slewing Bearings

Why do engineers choose four-point contact ball slewing bearings over other options? Here are the main benefits:

One bearing does the work of several
A single four-point contact ball slewing bearing handles axial loads, radial loads, and tilting moments together. You no longer need separate bearing types in your assembly.

Small and light
The single-row design uses just two seat rings. This simplicity saves valuable space and keeps weight low, helping you build more compact machinery.

Handles high static loads with ease
The four-point contact pattern spreads loads efficiently. The bearing can support extremely high static loads without permanent damage.

Works equally well for both axial directions
Many bearings only accept axial loads from one direction. This design accepts axial forces from either direction without any performance difference.

Turns smoothly with low resistance
Precision-ground raceways and quality steel balls deliver quiet, easy rotation. You get lower power consumption and reduced wear over time.

Built to last
This bearing series suits equipment that demands high axial loads, strong overturning moment resistance, continuous operation, and a long service life.

Customizable for your environment
Based on your specific working conditions, LDB can modify the sealing structure and internal fixator to match your needs.

Common Applications of Four-Point Contact Spherical Slewing Bearings

You will find these bearings working hard in many different types of equipment:

Construction machinery
Rotary conveyors, welding robots, manipulators, small and medium cranes, and excavators all rely on these bearings. Their ability to manage combined loads makes them perfect for rotating equipment under heavy weight.

Tower parking systems
Automated parking garages use four-point contact ball slewing bearings to rotate car platforms with precision and smoothness.

Cranes and hoists
Mobile cranes, tower cranes, and marine cranes all depend on these bearings for their slewing functions.

Excavators and earthmoving gear
Both medium-sized and small excavators benefit from the compact size and high load capacity of this bearing type.

Wind turbines
Many yaw and pitch systems in wind turbines use these bearings because they handle combined loads well in outdoor conditions.

Medical equipment
Large medical imaging machines and robotic surgery systems use these bearings for accurate rotational positioning.

Key Factors When Choosing a Four-Point Contact Ball Slewing Bearing

Before you order a slewing bearing, consider these important factors:

Load demands
Figure out the maximum axial load, radial load, and tilting moment your application will create. LDB’s rated load range of 129kN to 3,410kN suits most medium and heavy-duty jobs. Send your load data to our team for precise sizing.

Gear type
Pick no gear, internal gear, or external gear based on your drive layout. Internal gear works when your motor mounts inside the bearing ring. External gear fits when your motor sits outside.

Ring design
Choose integral ring for maximum rigidity. Choose split ring for easier adjustment during installation. LDB pre-assembles split rings with bolts before shipping to save you time.

Size specifications
Tell us your required inner diameter (100mm to 8,000mm) and outer diameter (200mm to 10,000mm). Ball diameter (30mm to 75mm) affects both load capacity and rotation smoothness.

Seal needs
Standard nitrile rubber seals work for most environments. For harsh or dusty conditions, LDB can create special sealing designs to keep contaminants away.

Hardness requirements
Check that hardness levels match your application. LDB delivers normalizing hardness of 187HB-241HB, quenched and tempered hardness of 229HB-269HB, and raceway hardness of HRC 55-62.

Cage vs. full-ball
Use a cage design for most standard applications. Choose the full-ball structure only when you need maximum load capacity and can accept higher friction.

Delivery schedule
LDB’s standard delivery takes 10 to 30 days. For urgent projects, contact us to discuss faster options.

Standard or custom
LDB keeps common standard models in stock. For non-standard requirements, we design and manufacture according to your exact specifications.

LDB: Custom Four-Point Contact Ball Slewing Bearings Manufacturer

LDB stands as a professional enterprise dedicated to the design, development, manufacturing, and sales of precision slewing bearings and slewing drives. We deliver high-performance small and large slewing rings to customers across the globe.

What makes LDB different from other suppliers? We offer fully customized slewing bearing solutions. Our team integrates advanced monitoring systems, lubrication mechanisms, and sealing technologies to give you higher reliability and extended service life. Our comprehensive service offerings help you reduce costs while optimizing performance. Thanks to our worldwide presence, we can deliver solutions and support quickly no matter where you are located.

Customization options
LDB supplies complete slewing bearing sets with no gear, external gear, internal gear, or individual ring gears based on your specific requirements. We can redesign the sealing structure and internal fixator to match your working environment perfectly. For split ring designs, we pre-connect the two halves with bolts before shipment to make your installation process easier.

Quality you can trust
Every bearing passes through rigorous quality checks before leaving our factory. We verify dimensional accuracy, hardness levels, gear quality, and raceway surface finish. Our heat treatment process includes normalizing, quenching and tempering, and induction hardening to achieve the target raceway hardness of HRC 55-62.

Packaging and shipping
Each bearing travels in a metal bracket or an export-standard fumigation-free wooden box. This packaging guarantees safe delivery to any destination worldwide. We back every product with a 12-month warranty and a standard lead time of 10 to 30 days.

Technical support
LDB maintains inventory of common standard models for quick shipment. For non-standard requirements, our engineering team designs and manufactures to your specifications. Whether you need a standard product or a fully custom solution, we work closely with you to meet your goals.

Contact LDB today to discuss your four-point contact ball slewing bearing requirements. Share your load data, size specifications, gear configuration, and any special needs. We will provide a competitive quote, technical recommendations, and a reliable delivery schedule.

Large Slewing Bearings: Key Applications and Engineering Insights

What Are Large Slewing Bearings?

Large slewing bearings are heavy-duty, oversized rotational components designed to handle complex loads that standard bearings cannot manage. Unlike conventional bearings that typically support only radial or axial loads individually, large slewing bearings are specifically engineered to accommodate radial forces, axial forces, and tilting moment loads simultaneously. This unique capability makes them essential for any machinery that requires smooth, controlled rotation while supporting significant weight.

A typical large slewing bearing consists of an inner ring, an outer ring, a set of rolling elements (steel balls or rollers), and often gear teeth integrated into one of the rings. These components are manufactured from high-strength steel alloys such as 42CrMo or 50Mn, with raceways induction-hardened to achieve surface hardness of HRC 55-62. The result is a durable, reliable component that can operate for decades under extreme conditions.

How Do Large Slewing Bearings Handle Complex Loads?

The working principle of large slewing bearings lies in their unique raceway geometry and multiple rows of rolling elements. Depending on the specific design – whether single-row four-point contact, double-row ball, or cross-roller – these bearings distribute applied forces across multiple contact points between the rolling elements and the raceways.

In a Four Point Contact Ball Slewing Bearing , each steel ball contacts the raceway at four distinct points – two on the inner ring and two on the outer ring. This geometry allows the bearing to manage axial loads from either direction, radial loads, and tilting moments within a single, compact row. In double-row designs, there are two separate raceways and eight points of contact per ball, providing even higher load capacity and greater structural rigidity.

When a piece of heavy machinery operates – for example, a crane lifting a steel beam – the slewing bearing at its base experiences downward axial force from the weight, radial force from the boom’s extension, and a tilting moment that tries to tip the structure. The bearing’s internal geometry resists all three forces simultaneously, keeping the rotation smooth and the structure stable.

Common Applications of Large Slewing Bearings Across Major Industries

Large slewing bearings are the unsung heroes behind many of the world’s most impressive machines. Their ability to enable smooth rotation under extreme loads makes them indispensable across four major industrial sectors.

Heavy Construction and Earthmoving Equipment

The construction industry relies heavily on rotational machinery. On any major building site, large slewing bearings are hard at work. Tower cranes and mobile cranes use these bearings at their base or turntable to allow the boom to swing a full 360 degrees while carrying immense weight. Without a reliable slewing bearing, the crane could not rotate smoothly or safely.

Excavators represent another critical application. A slewing ring is mounted between the undercarriage (tracks) and the main body (cabin). This allows the operator to rotate the cabin and digging arm independently of the track direction, drastically improving digging efficiency and site mobility. Whether the machine is digging a foundation or loading trucks, the slewing bearing enables continuous, precise rotation under heavy and often shock loads.

Renewable Energy Systems

The global push for green energy has created massive demand for precision engineering, and large slewing bearings are absolutely essential in this sector, particularly in wind and solar power.

On wind turbines, two types of slewing bearings are critical. Yaw bearings are installed between the tower and the nacelle (the housing at the top containing the generator). They allow the entire nacelle to rotate and face directly into the wind, optimizing energy capture as wind direction changes. Pitch bearings are mounted at the base of each turbine blade, allowing the blade angle to be adjusted. This adjustment optimizes power capture during normal operation and feathers the blades to prevent damage during severe storms.

In large-scale solar farms, dual-axis solar trackers incorporate slewing bearings to follow the sun’s trajectory across the sky. By keeping solar panels oriented directly at the sun throughout the day, these systems can increase energy absorption by 30-40% compared to fixed installations.

Marine and Offshore Industries

The marine and offshore sectors demand equipment that can withstand harsh, corrosive environments while managing extreme loads. Deck cranes on cargo ships, which lift containers from holds to docks, rely on large slewing bearings for their rotational function. Offshore oil rig platforms use slewing bearings in cranes and pipe-handling equipment, where saltwater spray and constant motion create uniquely challenging conditions.

Specialized underwater remotely operated vehicles (ROVs) used for subsea inspection and maintenance also incorporate compact slewing bearings in their manipulator arms and thrusters. In all these marine applications, slewing bearings are often custom-engineered with specialized anti-corrosive coatings and superior sealing systems to prevent saltwater intrusion and ensure a long operational lifespan.

Industrial Robotics and Manufacturing

The automation of heavy manufacturing requires robust rotational joints. Heavy-duty industrial robots – such as those used in automotive assembly lines to lift and position car chassis – rely on slewing bearings at their base and major pivot points. These bearings must provide not only high load capacity but also precise positioning and low friction for accurate, repeatable movements.

Large industrial turntables, packaging machines, and material handling systems use slewing rings to index heavy loads quickly and accurately. For example, a turntable in a manufacturing cell might rotate a heavy engine block between multiple workstations. The slewing bearing ensures smooth, precise indexing, keeping production lines moving without interruption.

Core Advantages of Large Slewing Bearings Across Industries

Large slewing bearings offer several distinct advantages that make them the preferred choice for demanding rotational applications.

High Load Capacity – These bearings are designed to handle massive static and dynamic loads. Depending on size and configuration, a single large slewing bearing can support hundreds of tons while maintaining smooth rotation.

Combined Load Management – Unlike standard bearings that struggle with multiple load directions, large slewing bearings are specifically engineered to simultaneously manage axial, radial, and tilting moment forces.

Compact Integration – By combining load support and rotational guidance into a single component, slewing bearings simplify machine design. The ability to integrate gear teeth directly into the bearing ring eliminates the need for separate drive components.

Durability in Harsh Environments – With proper material selection, heat treatment (HRC 55-62 raceway hardness), and sealing systems, large slewing bearings can operate reliably for decades in environments ranging from dusty construction sites to corrosive offshore platforms.

Customizability – Large slewing bearings can be tailored to specific applications, including choices of gear type (internal, external, or no gear), ring material (42CrMo, 50Mn, C45), rolling elements (balls or rollers), and sealing arrangements.

Selecting the Right Large Slewing Bearing

Not all slewing bearings are created equal. Because the applications for large slewing bearings involve such extreme weights and critical safety standards, choosing the right specification is vital.

Engineers must carefully calculate the following factors before selecting a bearing:

Load requirements – Maximum axial load, radial load, and tilting moment (kN·m) that the bearing will experience under normal and peak operating conditions.
Rotational speed – While large slewing bearings typically operate at slow speeds, the number of rotations per day or year affects fatigue life calculations.
Environmental conditions – Temperature extremes, dust, moisture, chemical exposure, and the presence of saltwater or other corrosives all influence material and seal selection.
Mounting structure – The stiffness and flatness of the supporting structure affect load distribution across the bearing.
Drive configuration – Gear type (internal, external, or no gear) must match the machine’s drive system.
Maintenance access – Available space for lubrication fittings, inspection, and potential replacement should be considered early in the design process.

Working with an experienced manufacturer that provides engineering support during the selection process helps ensure that the final bearing meets both performance requirements and operational expectations.

Conclusion

Large slewing bearings are critical components that enable rotation in heavy machinery across construction, renewable energy, marine, and industrial automation sectors. Their ability to simultaneously handle axial loads, radial loads, and tilting moments makes them indispensable for equipment ranging from tower cranes and excavators to wind turbines and solar trackers.

By understanding what these bearings are, how they work, and where they are applied, engineers and equipment operators can make informed decisions that improve machine reliability and operational safety. The right slewing bearing – properly selected, correctly installed, and regularly maintained – will provide decades of trouble-free service, turning silently beneath thousands of tons of steel and concrete.

LDB: A Trusted Supplier of Large Slewing Bearings

LDB (Luoyang Longda) is a professional manufacturer specializing in the production and sales of high-quality slewing bearings, slewing drives, and gear transmission devices. With years of experience in the industry, LDB serves customers across construction machinery, renewable energy, marine equipment, and industrial automation.

LDB’s large slewing bearings are manufactured using premium materials including 42CrMo, 50Mn, and C45, with rolling elements made from GCr15 bearing steel. Raceways are induction-hardened to HRC 55-62, providing excellent wear resistance and long operational life. Outer diameters range from 300 mm to 10,000 mm, and gear configurations include no gear, internal gear, or external gear to suit various drive systems.

LDB offers a standard lead time of 30 days for custom orders, with flexible customization options including ring material, cage material (steel 20 or ZL112 cast aluminum alloy), spacer material (nylon 6 or nylon 66), and sealing systems. All products undergo rigorous inspection and testing before shipment, including dimensional accuracy, rotational torque, and raceway hardness checks. Finished bearings are protected with anti-corrosion oil and packaged in metal brackets or export-standard fumigation-free wooden boxes.

Whether the application is a tower crane on a construction site, a yaw bearing in a wind turbine, a deck crane on a cargo ship, or a turntable in an automated manufacturing line, LDB provides reliable, custom-engineered large slewing bearings that meet demanding performance requirements.

FAQ: Common Questions About Large Slewing Bearing Applications

Q1: What is the difference between a single-row and a double-row large slewing bearing?

A single-row slewing bearing typically uses a four-point contact ball design, where each ball contacts the raceway at four points, allowing it to handle axial loads from both directions, radial loads, and tilting moments in one compact row. A double-row slewing bearing uses two separate rows of balls with eight points of contact per ball, providing higher load capacity, greater rigidity, and longer service life for the most demanding applications such as wind turbines and concrete pump trucks.

Q2: How often do large slewing bearings need maintenance?

Maintenance intervals depend on the application, operating environment, and duty cycle. For construction equipment like excavators and cranes, lubrication is typically required every 150-200 operating hours or weekly. For wind turbines, yaw and pitch bearings are often lubricated at scheduled service intervals every 6-12 months. Marine applications may require more frequent inspection due to corrosive saltwater exposure. Always follow the manufacturer’s recommendations for lubrication type and frequency.

Q3: Can large slewing bearings be repaired, or must they be replaced when damaged?

Minor damage such as localized pitting or surface corrosion can sometimes be repaired through re-grinding raceways or replacing rolling elements. However, significant damage to raceways, gear teeth, or ring structural integrity typically requires full replacement. LDB offers engineering support to assess bearing condition and recommend the most cost-effective solution, including remanufacturing services for certain bearing types.

Q4: What factors shorten the service life of a large slewing bearing?

The most common factors include inadequate or contaminated lubrication, improper installation (uneven mounting surfaces or incorrect bolt torque), exceeding rated load capacities, exposure to severe contamination (sand, water, chemicals), and lack of regular inspection. Proper selection, correct installation, and a disciplined maintenance program are essential to achieving the bearing’s expected service life.

Q5: How do I select the right gear type (internal, external, or no gear) for my application?

External gear configurations are most common for construction machinery like excavators and cranes, where the pinion drives the outer ring. Internal gears are often preferred for wind turbines and compact installations where space is limited and the drive pinion can be placed inside the bearing envelope. No gear (plain) bearings are used when rotation is driven by friction rollers or separate ring gears. The choice depends on your machine’s drive system design, available space, and maintenance access requirements.

Delivery of Komatsu Excavator Slewing Ring to South America

May 8, 2026/in LDB Company News /by LDB Bearing

In the field of construction machinery, the quality and timely delivery of slewing rings directly affect the stable operation of host equipment. In August 2021, our company successfully completed a supply task for a Komatsu excavator slewing ring to a client in South America. This case demonstrates our supply chain capability and professional understanding of the Four-Point Contact Ball Slewing Bearing.

The slewing ring supplied is of the four-point contact ball type. This bearing features a single raceway design where each ball contacts the raceway at four distinct points, allowing it to simultaneously withstand axial loads, radial loads, and tilting moments. Compared to other designs, it offers higher load efficiency, a compact cross-section, and good impact resistance, making it particularly suitable for excavators.

The client in South America explicitly requested a four-point contact ball slewing bearing for their Komatsu excavator. After order confirmation, our company strictly controlled every stage of production, inspection, and packaging. The slewing rings were shipped in August 2021 via a dedicated South America logistics route. Each unit underwent dimensional accuracy, rotational flexibility, hardness, and flaw detection tests to confirm compliance with Komatsu standards. Anti-corrosion treatment and reinforced packaging were applied for long-distance ocean transportation.

Upon arrival in South America, the slewing rings were installed and tested. The customer reported excellent performance, including low friction, high rigidity, and stable rotational accuracy, effectively reducing slewing noise and vibration. This case proves our company’s professional capability in critical components for construction machinery, from product selection and quality control to international logistics.

What is a Four Point Contact Ball Slewing Bearing?

A four point contact ball slewing bearing is a precision rotary component primarily composed of an inner ring, an outer ring, a single row of steel balls, a cage (or spacer), and sealing devices. Both the inner and outer rings can be manufactured as either integral or split structures. Integral rings offer higher rigidity, while split rings allow for easier adjustment. For split structures, bolts are used to connect the two split rings before the product leaves the factory.

This type of slewing bearing generally includes a cage or spacer to separate the balls. However, a full-ball (no cage) structure is used when load requirements are relatively high. The full-ball design provides larger load capacity but comes with higher frictional resistance, which can potentially cause scratches on the surface layer of the steel balls.

The basic structure of a four point contact ball slewing bearing is available in three gear configurations: without gear, with external gear, or with internal gear. All configurations offer high static load capacity. As a product of LDB (Luoyang Longda), this bearing type is manufactured with materials including 42CrMo and 50Mn, with nitrile rubber seals as standard.

How Does a Four Point Contact Ball Slewing Bearing Work?

The working principle of a four point contact ball slewing bearing is based on its unique Gothic arch raceway geometry. Unlike conventional ball bearings where the ball contacts the raceway at two points, this design allows each steel ball to make contact at four points – two on the inner ring and two on the outer ring.

When loads are applied, the contact points engage as follows:

Pure axial load in one direction: Two of the four contact points become active
Reversed axial load: The opposite pair of contact points engages
Combined loads (axial + radial + tilting moment): All four contact points share the load simultaneously

This load distribution mechanism enables a single-row bearing to perform functions that would otherwise require two separate rows. The single-row four-point contact ball slewing bearing consists of two seat rings, offering a compact structure and light weight. The four-point contact between the steel ball and the arc raceway allows the bearing to bear axial force, radial force, and tilting moment at the same time. This is achieved because the Gothic arch raceway profile creates a precise contact geometry that distributes loads efficiently across the bearing.

Key Features of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers a range of distinctive engineering features:

Single-row compact design: Consists of only two seat rings (inner and outer), providing a compact structure with light weight
Four-point contact geometry: Steel balls contact the arc raceway at four points, enabling combined load handling (axial, radial, and tilting moment simultaneously)
Multiple gear options: Available as no gear, internal gear, or external gear to suit various drive configurations
Flexible ring structure: Choice between integral rings (higher rigidity) and split rings (easier adjustment)
Cage or full-ball options: Caged designs for standard applications; full-ball designs for higher load capacity with the trade-off of increased friction
High static load capacity: Engineered to withstand demanding static and dynamic conditions
Wide dimensional range: Outer diameter from 300 mm to 10,000 mm, ball diameter from 30 mm to 75 mm
High load rating: Rated load from 129 kN to 3,410 kN
Fast delivery: Standard lead time of 10–30 days for custom orders

LDB specific features:

Materials: 42CrMo and 50Mn high-grade steel
Seal type: Nitrile rubber for effective contamination protection
Hardness: Normalizing hardness 187-241 HB, quenched and tempered hardness 229-269 HB, raceway quenching hardness HRC 55-62
Inner diameter range: 100 mm to 8,000 mm
Warranty: 12 months

Main Types of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings can be classified based on three main criteria: gear configuration, ring structure, and ball arrangement.

1. By gear configuration:

No gear (plain): For applications where the drive system does not require gear engagement
Internal gear: Gear teeth cut on the inner ring, suitable for compact drive designs where space is limited
External gear: Gear teeth cut on the outer ring, commonly used in excavators, cranes, and turntables

2. By ring structure:

Integral ring design: Higher rigidity, suitable for heavy-duty applications requiring maximum structural integrity
Split ring design: Allows for easier adjustment and maintenance; bolts connect the two split rings before the product leaves the factory

3. By ball arrangement:

Caged design: Standard configuration with spacers or cages to reduce friction and prevent ball-to-ball contact
Full-ball design: No cage or spacer, providing higher load capacity but increased frictional resistance; friction can also easily cause scratches on the surface layer of the steel ball

Core Advantages of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers several distinct advantages over other slewing bearing types:

Combined load capability: Can simultaneously bear axial force, radial force, and tilting moment within a single row, eliminating the need for multiple bearing arrangements
Compact and lightweight: The single-row two-seat-ring design saves space and reduces overall machine weight, making it ideal for mobile equipment
Bidirectional axial load support: Handles thrust loads from both directions without additional raceways or bearings
High static load capacity: Suitable for applications with heavy shock loads and intermittent rotation patterns common in construction machinery
Design flexibility: Customizable gear type (no gear, internal gear, external gear), ring structure (integral or split), and ball arrangement (caged or full-ball) to meet specific requirements
Long service life: Optimized sealing and lubrication options extend operational life, especially in harsh environments
Cost-effective: Lower manufacturing and maintenance costs compared to double-row or cross-roller alternatives
Fast customization: 10–30 day delivery for custom orders enables rapid project execution

LDB product advantages:

This series of slewing ring is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation
Sealing structure and internal fixator can be optimized based on the specific working environment requirements
Both standard and non-standard models available – non-standard models designed and manufactured to customer requirements
Complete sets available without gears, with external gears, with internal gears, or individual ring gears
Secure packaging: metal bracket or export-standard fumigation-free wooden box

Common Applications of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings are widely used across various industries, particularly in construction machinery. Based on LDB’s application scope, common applications include:

Construction and heavy machinery:

Rotary conveyors
Welding robots and manipulators
Small and medium cranes
Excavators (turntable applications)
Aerial work platforms

Other industrial applications:

Solar tracking systems
Wind turbine yaw and pitch systems
Industrial turntables and indexing tables
Medical imaging equipment (CT scanners)
Material handling equipment
Radar and antenna rotators
Packaging machinery

The four point contact ball slewing bearing is especially suitable for applications that demand high axial load capacity, resistance to overturning moment, and continuous operation with extended service life. The single-row four-point contact ball slewing bearing is particularly well-suited for main engines with large axial load, high overturning moment, high service life requirements, and continuous operation.

How to Select the Right Four Point Contact Ball Slewing Bearing?

Selecting the correct four point contact ball slewing bearing for your application requires careful consideration of the following factors:

Selection Factor	Considerations
Load requirements	Calculate axial load, radial load, and tilting moment (kN·m). LDB’s rated load range is 129–3,410 kN.
Dimensional constraints	Verify outer diameter (300–10,000 mm), inner diameter (100–8,000 mm), and ball diameter (30–75 mm) fit your mounting space.
Gear configuration	Choose no gear, internal gear, or external gear based on your drive system design.
Ring structure	Select integral ring for higher rigidity or split ring for easier adjustment.
Ball arrangement	Choose caged design for standard applications with lower friction, or full-ball design for higher load capacity (note: full-ball design has higher friction and may cause scratches on steel ball surface).
Operating environment	Consider temperature, dust, moisture, and chemical exposure. LDB uses nitrile rubber seals as standard, with customization available for special environments.
Material and hardness	LDB offers 42CrMo and 50Mn materials with raceway quenching hardness HRC 55-62 for optimal wear resistance.
Precision requirements	Specify required tolerances for your application.
Delivery schedule	LDB standard lead time is 10–30 days for custom orders.
Warranty	LDB offers 12 months warranty on all slewing bearings.

Additional selection tips:

For large axial loads and overturning moments with continuous operation, the single-row four-point contact ball slewing bearing is highly recommended
LDB can optimize sealing structure and internal fixator design based on your specific working environment
Both standard and non-standard models are available – contact LDB for non-standard requirements
Consider the total cost of ownership, including maintenance intervals and expected service life

LDB ：Custom Four Point Contact Ball Slewing Bearings Manufacturer

LDB (Luoyang Longda) is a professional enterprise specializing in the production and sales of slewing bearings (slewing rings), slewing drives, and gear transmission devices. As a reliable supplier of high-performance rotary components, LDB serves industries ranging from construction machinery to renewable energy.

LDB four point contact ball slewing bearing specifications:

Parameter	LDB Range / Value
Brand	LDB (Luoyang Longda)
Outer diameter	300 mm – 10,000 mm
Inner diameter	100 mm – 8,000 mm
Ball diameter	30 mm – 75 mm
Rated load	129 kN – 3,410 kN
Gear type	No gear, internal gear, external gear
Delivery lead time	10 – 30 days
Material	42CrMo, 50Mn
Seal type	Nitrile rubber
Rolling element	Steel ball
Normalizing hardness	187 HB – 241 HB
Quenched and tempered hardness	229 HB – 269 HB
Raceway quenching hardness	HRC 55 – 62
Warranty	12 months
Packaging	Metal bracket or export standard fumigation-free wooden box

LDB product advantages:

Superior design: The single-row four-point contact ball slewing bearing is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation.
Customizable engineering: According to the requirements of the supporting working environment, LDB can optimize the design of the sealing structure and the internal fixator.
Flexible manufacturing: LDB maintains commonly used standard models, and non-standard models can be designed and manufactured according to customer requirements.
Complete solutions: LDB provides complete sets of slewing bearings without gears, with external gears, with internal gears, or individual ring gears according to customer requirements.
Secure packaging: All products are shipped in metal brackets or export-standard fumigation-free wooden boxes to ensure safe delivery.

Why choose LDB?

Experience: Years of expertise in slewing bearing design and manufacturing
Quality: High-grade materials (42CrMo, 50Mn) with precision heat treatment and raceway hardening to HRC 55-62
Customization: Full engineering support for non-standard models
Speed: 10-30 day delivery for custom orders
Warranty: 12 months on all products
Global shipping: Reliable logistics network supporting delivery worldwide

Whether you need a four point contact ball slewing bearing for an excavator turntable, a crane, a welding robot, a rotary conveyor, or any other rotary application, LDB delivers custom-engineered solutions with fast lead times and dependable quality.

Contact LDB today to discuss your specific four point contact ball slewing bearing requirements．

Slewing Bearing in Crane: The Ultimate Guide to Function, Types, and Maintenance

May 8, 2026/in Bearing Knowledge, Slewing Bearing Knowledge /by LDB Bearing

What is a Slewing Bearing in a Crane?

A slewing bearing, often referred to as a slewing ring or turntable bearing, is a large rotational rolling-element bearing specifically designed to support heavy, slow-turning, or slow-oscillating loads. In crane applications, the slewing bearing acts as the pivotal joint between the crane’s stationary undercarriage (the lower structure) and the rotating upper structure, which includes the cab, boom, and lifting mechanism.

Unlike standard bearings found in automotive wheels or small machinery, slewing bearings are engineered to handle complex forces simultaneously. These forces include three distinct load types:

Axial loads – The downward vertical weight of the crane’s upper structure and the load being lifted.
Radial loads – Horizontal forces caused by wind pressure, centrifugal motion during rotation, or side pulls.
Tilting moments – The leverage effect created when a heavy load is suspended at the end of a long boom, which tries to tip the crane over.

A typical slewing bearing consists of an inner ring, an outer ring, a set of rolling elements (steel balls or rollers), and often gear teeth integrated into one of the rings. This compact yet robust design enables the crane to rotate smoothly while supporting immense weight.

How Does a Slewing Bearing Work in a Crane?

The working principle of a slewing bearing in a crane is based on its unique raceway geometry and the arrangement of rolling elements. When the crane’s upper structure rotates, the slewing bearing allows this movement while simultaneously resisting the three types of forces described above.

In a four point contact ball slewing bearing, which is commonly used in medium-duty cranes, each steel ball contacts the raceway at four distinct points – two on the inner ring and two on the outer ring. This geometry allows the bearing to manage axial loads from either direction (upward or downward), radial loads, and tilting moments within a single, compact row of balls.

When the crane operates – for example, lifting a heavy steel beam at the end of a long boom – the slewing bearing experiences downward axial force from the weight, radial force from the boom’s extension, and a tilting moment that tries to tip the structure forward. The bearing’s internal geometry resists all three forces simultaneously, keeping the rotation smooth and the crane stable.

For larger, more demanding crane applications, double-row ball bearings or three-row roller slewing bearings are used. These designs provide additional load paths and greater structural rigidity, distributing forces across multiple rows of rolling elements and significantly increasing load capacity.

Why is the Slewing Bearing Crucial for Crane Safety and Performance?

The performance and safety of any lifting equipment rely heavily on its foundational components. The slewing bearing is absolutely essential for crane operation for three primary reasons.

Flawless 360-Degree Rotation – Efficiency on a construction site requires agility. The slewing bearing allows the crane’s boom to rotate continuously in any direction, making material handling faster and highly precise. Without a reliable slewing bearing, the crane could not position loads accurately or respond quickly to changing site conditions.

Massive Load Distribution – Cranes routinely lift thousands of kilograms. The slewing bearing acts as the load-bearing spine of the machine, distributing this massive weight evenly across the undercarriage to prevent structural failure. Proper load distribution also protects the crane’s chassis and mounting structure from localized stress concentrations.

Operational Stability – A high-quality, perfectly fitted bearing prevents wobbling and unwanted movement. It ensures the crane remains balanced during operation, significantly reducing the risk of tipping or swaying during a heavy lift. This stability is especially critical when operating at height or in windy conditions.

In short, the slewing bearing is the component that enables a crane to be both powerful and precise. Without it, the crane could not rotate safely, and the risk of mechanical failure or catastrophic tip-over would increase dramatically.

Common Types of Slewing Bearings Used in Cranes

Different crane designs and duty cycles require different load capacities. Consequently, manufacturers use a variety of slewing bearing types based on the crane’s intended workload. The three most common types are as follows.

Single-Row Four-Point Contact Ball Bearings – These bearings are ideal for light to medium-duty mobile cranes, truck-mounted cranes, and smaller tower cranes. They offer excellent cost-effectiveness and handle dynamic loads well within their rated capacity. The four-point contact geometry provides a compact solution for applications where space and weight are considerations.

Double-Row Ball Bearings – By utilizing two separate rows of steel balls with eight points of contact per ball, these bearings provide higher load capacity and greater stability than single-row designs. They are frequently used in medium-sized tower cranes, crawler cranes, and larger mobile cranes that operate at higher duty cycles.

Three-Row Roller Slewing Bearings – These bearings are designed for the absolute heaviest lifting applications. They feature three independent rows of rolling elements: one row for axial loads (upward), one row for axial loads (downward), and one row for radial loads. If you see a massive offshore crane, a heavy-duty crawler crane lifting hundreds of tons, or a large port crane, it almost certainly uses a three-row roller bearing to handle extreme axial and radial loads safely.

Each type has its place in the crane industry. The selection depends on factors such as maximum lift capacity, rotational speed, duty cycle, and cost constraints.

Top Maintenance Tips for Crane Slewing Bearings

Replacing a slewing bearing is incredibly expensive and causes massive operational downtime. To maximize the lifespan of a slewing bearing in crane operations, regular maintenance is non-negotiable. The following essential tips should be followed.

Consistent Lubrication – Friction is the primary enemy of any bearing. Apply high-quality grease to the raceways and gear teeth strictly according to the manufacturer’s recommended schedule. Insufficient lubrication leads to metal-to-metal contact, rapid wear, and eventual bearing failure. Over-lubrication can also cause seal damage, so follow the specified quantity and frequency.

Check Bolt Tension – The bolts securing the slewing ring to the crane structure experience immense and variable stress. Regularly inspect and tighten these bolts to the required torque specifications using calibrated torque tools. Loose bolts allow relative movement between the bearing and mounting structure, leading to fretting corrosion, bolt fatigue, and potential bearing misalignment.

Monitor for Wear and Tear – Pay close attention to unusual grinding noises, excessive vibrations, or jerky movements during rotation. These are early warning signs of internal bearing degradation such as spalling, pitting, or ball damage. Any change in rotational smoothness should trigger an immediate inspection.

Protect from Debris – Ensure the bearing’s protective seals remain intact and undamaged. Dirt, sand, water, and other contaminants can severely damage the internal rolling elements if they bypass the seals. In dusty construction environments or marine applications, more frequent seal inspection and cleaning are recommended.

Additionally, keep detailed maintenance records including lubrication dates, bolt torque checks, and any observed abnormalities. These records help predict bearing life and schedule replacement before a catastrophic failure occurs.

Selecting the Right Slewing Bearing for Your Crane

Choosing the correct slewing bearing for a crane application requires careful evaluation of multiple factors. Engineers should consider the following key parameters before making a selection.

Load Requirements – Calculate the maximum axial load, radial load, and tilting moment (in kN·m) that the bearing will experience under normal and peak operating conditions. These values determine the required bearing size, type, and internal geometry.

Rotational Speed – While crane slewing bearings typically operate at slow speeds (often less than 2-3 revolutions per minute), the number of rotations per day or year affects fatigue life calculations. High-cycle applications such as port cranes require different design considerations than occasional-use mobile cranes.

Installation Space and Mounting Dimensions – The available space for the bearing determines maximum outer diameter, minimum inner diameter, and bolt circle diameter. The mounting structure’s flatness and stiffness must also be evaluated to ensure proper load distribution.

Precision and Rigidity Requirements – Some crane applications, such as those requiring precise load positioning or robotic control, demand higher rotational accuracy and greater structural rigidity. This influences the choice between ball bearings and roller bearings, as well as the internal clearance specifications.

Environmental Conditions – Temperature extremes, dust, humidity, and saltwater exposure all affect material selection, sealing systems, and corrosion protection requirements. Outdoor cranes in coastal areas benefit from anti-corrosion coatings and upgraded seals.

LDB: A Trusted Supplier of Custom Crane Slewing Bearings

LDB (Luoyang Longda) is a professional manufacturer specializing in the production and sales of high-quality slewing bearings, slewing drives, and gear transmission devices. With years of experience in the industry, LDB serves crane manufacturers and operators worldwide, providing custom-engineered solutions for mobile cranes, tower cranes, crawler cranes, and offshore cranes.

LDB’s crane slewing bearings are manufactured using premium materials including 42CrMo, 50Mn, and C45, with rolling elements made from GCr15 bearing steel. Raceways are induction-hardened to HRC 55-62, providing excellent wear resistance and long operational life even under heavy cyclic loading. Outer diameters range from 300 mm to 10,000 mm, accommodating everything from small truck-mounted cranes to massive port cranes.

For crane applications, LDB offers flexible customization options including:

Gear configurations: no gear, internal gear, or external gear
Ring materials: 42CrMo, 50Mn, C45 based on strength and cost requirements
Cage materials: steel 20 or ZL112 cast aluminum alloy
Spacer materials: nylon 6 or nylon 66
Sealing systems: standard nitrile rubber or custom designs for harsh environments

LDB offers a standard lead time of 30 days for custom orders. All products undergo rigorous inspection and testing before shipment, including dimensional accuracy checks, rotational torque testing, and raceway hardness verification. Finished bearings are protected with anti-corrosion oil and packaged in metal brackets or export-standard fumigation-free wooden boxes.

Whether you need a single-row four-point contact bearing for a mobile crane, a double-row ball bearing for a tower crane, or a three-row roller bearing for a heavy-lift crawler crane, LDB provides reliable, custom-engineered solutions backed by engineering support and a 12-month warranty.

FAQ About Slewing Bearings in Cranes

Q1: How often should the slewing bearing on a crane be lubricated?

Lubrication frequency depends on crane usage and operating conditions. For cranes in daily construction use, lubrication is typically recommended every 150-200 operating hours or weekly. For cranes used intermittently, lubrication every month is usually sufficient. Always follow the manufacturer’s specifications for grease type and quantity. Heavy-duty or high-cycle applications may require more frequent lubrication.

Q2: What are the signs that a crane slewing bearing is failing?

Common warning signs include grinding or clicking noises during rotation, excessive vibration or wobbling, jerky or uneven rotational movement, increased resistance when slewing, and visible rust or pitting around seals. If any of these symptoms appear, the bearing should be inspected immediately by qualified personnel. Continued operation with a failing bearing risks sudden failure and potential crane tip-over.

Q3: How long does a slewing bearing last in a typical crane?

With proper installation, regular maintenance, and operation within rated load limits, a crane slewing bearing can last 10 to 15 years or more. Factors that reduce service life include inadequate lubrication, overloading, contamination ingress, and improper bolt torque. Cranes in harsh environments or with very high duty cycles may require replacement sooner.

Q4: Can a crane slewing bearing be repaired instead of replaced?

Minor damage such as localized surface pitting may be repairable through re-grinding raceways or replacing rolling elements. However, significant damage to raceways, gear teeth, or ring structural integrity typically requires full replacement. An experienced manufacturer can assess the bearing condition and recommend the most cost-effective solution. For critical crane applications, replacement is often the safer and more reliable option.

Q5: What is the typical lead time for a custom crane slewing bearing from LDB?

LDB offers a standard lead time of 30 days for custom crane slewing bearings. This includes material selection, precision machining, heat treatment, assembly, and final inspection. For non-custom, standard-size bearings, shorter lead times may be available. Clients should consult LDB’s engineering team for specific project timelines.

Q6: What materials are best for crane slewing bearings operating in coastal environments?

For coastal or offshore crane applications, materials with good corrosion resistance are essential. LDB offers ring materials such as 42CrMo with specialized anti-corrosion coatings. Sealing systems should be upgraded to prevent saltwater ingress. Regular cleaning and more frequent lubrication inspections are also recommended for coastal operations.

Double Row Ball Slewing Bearings: LDB’s Innovation and Excellence

May 6, 2026/in Bearing Knowledge, Slewing Bearing Knowledge /by LDB Bearing

What is a Double Row Ball Slewing Bearing?

A double row ball slewing bearing is a large-scale precision rotary component that incorporates two independent rows of steel balls between the inner and outer rings. Unlike single-row slewing rings, which feature a single row of balls with four points of contact between each ball and the raceway, double row products offer two rows of ball bearings, two separate raceways, and eight points of contact for each ball. This fundamental difference allows double row bearings to handle higher loads and provide greater reliability compared to their single-row counterparts.

Single-row slewing rings are designed with a standard bearing raceway where each ball contacts the raceway at four points. This four-point contact design enables them to simultaneously withstand axial loads, radial loads, and tilting moments in a compact form. However, when applications demand higher load capacity or extended service life under continuous operation, double row ball slewing bearings become the preferred choice.

The same-diameter double row ball slewing bearing produced by LDB is specifically engineered for demanding applications such as wind turbine equipment and concrete pump trucks. In wind power equipment, for instance, the bearing is installed at the root of the propeller and functions as a side propeller, where it must endure constant rotation, vibration, and variable wind loads while maintaining precise alignment.

LDB’s double row ball slewing bearings are manufactured within an outer diameter range of 300 mm to 10,000 mm, accommodating both compact machinery and large-scale industrial systems. The ring materials are selected from 42CrMo, 50Mn, or C45 – all high-grade steel alloys known for their excellent hardenability, fatigue resistance, and impact strength. The balls or rollers are made from GCr15 bearing steel, a material specifically formulated for rolling element applications requiring high hardness and wear resistance. For cages, LDB offers steel 20 or ZL112 cast aluminum alloy; for spacers, nylon 6 or nylon 66 are available.

How Does a Double Row Ball Slewing Bearing Work?

The working principle of a double row ball slewing bearing centers on the separation of load paths. Because there are two distinct rows of balls and two separate raceways, each row can be optimized for specific load types. The upper row typically handles axial loads and tilting moments, while the lower row manages radial loads and supplementary axial forces. This division reduces internal stress concentrations and improves overall load efficiency.

When an axial load is applied downward onto the bearing, the upper row of balls compresses against its raceway, transferring force from the inner ring to the outer ring (or vice versa, depending on mounting orientation). If a tilting moment is introduced – for example, when a concrete pump truck’s boom extends outward – the load becomes uneven across the bearing circumference. The double row configuration resists this tilting by engaging both rows on opposite sides of the bearing, creating a restoring moment that maintains structural alignment.

The eight-point contact geometry (four points per ball, across two rows) provides a significant advantage in load distribution. Each ball contacts its respective raceway at four distinct points – two on the inner ring and two on the outer ring. This arrangement allows the bearing to distribute applied forces across a larger contact area, reducing peak stresses and extending fatigue life.

LDB’s engineering team utilizes finite element analysis during the design phase to optimize raceway curvatures, ball diameters, and ring thicknesses. For wind turbine applications – where the bearing is installed at the propeller root – this analysis ensures that the bearing can withstand not only static loads but also dynamic forces generated by wind gusts, blade pitch adjustments, and continuous rotation over decades of service.

Key Features of LDB’s Double Row Ball Slewing Bearings

LDB’s double row ball slewing bearings incorporate several distinctive features based on actual production specifications.

Eight-Point Contact Geometry – Unlike single-row slewing rings that offer four points of contact per ball, LDB’s double row design provides eight points of contact per ball (four on the upper row and four on the lower row). This increased contact area reduces stress concentration and enhances load distribution.

Wide Diameter Range – Outer diameters from 300 mm to 10,000 mm, accommodating everything from small industrial turntables to massive wind turbine yaw systems and concrete pump turntables.

Premium Material Selection – Ring materials include 42CrMo, 50Mn, and C45. Balls are manufactured from GCr15 bearing steel. Cages are available in steel 20 or ZL112 cast aluminum alloy. Spacers are offered in nylon 6 or nylon 66.

Raceway Hardness – The quenching hardness of the raceway reaches HRC 55-62, ensuring a hard, wear-resistant surface while maintaining sufficient core toughness to absorb shocks and impacts.

Flexible Gear Configurations – Available with no gear, internal gear, or external gear. Tooth type selection depends on the drive system design. For wind turbine applications, internal gearing is often preferred; for concrete pump trucks, external gearing is commonly used.

Lead Time – LDB offers a standard lead time of 30 days for custom orders.

Core Advantages and Competitive Edge

When compared to single-row slewing rings or other bearing types, LDB’s double row ball slewing bearings offer several distinct advantages.

Higher Load Capacity – Because there are two rows of balls and eight points of contact per ball, double row bearings can support significantly higher axial, radial, and tilting moment loads than single-row alternatives. This makes them ideal for applications where load requirements exceed the practical limits of four-point contact designs.

Greater Reliability – The redundant load path provided by two separate rows means that even if one row experiences uneven wear or localized damage, the other row can continue to support critical loads. This inherent redundancy translates directly into higher system reliability – a crucial factor for wind turbines and concrete pump trucks where unexpected downtime is costly.

Longer Service Life – Reduced contact stress per ball, combined with high-quality GCr15 ball material and raceway hardness of HRC 55-62, results in extended fatigue life. LDB’s double row bearings are engineered for continuous operation over many years, even under variable and impact loads.

Same-Diameter Efficiency – The same-diameter double row ball slewing bearing design offers optimized space utilization. By maintaining a consistent diameter while adding a second ball row, LDB maximizes load capacity without increasing the bearing’s physical footprint.

Application-Specific Engineering – For wind turbine equipment, the bearing is installed at the root of the propeller and acts as a side propeller. LDB customizes the bearing’s internal geometry, sealing system, and lubrication features to meet the unique demands of this application, including high cycle fatigue resistance and corrosion protection.

Flexible Material Choices – Clients can select from 42CrMo, 50Mn, or C45 ring materials based on their specific strength, weight, and cost requirements. Cage materials (steel 20 or ZL112 aluminum alloy) and spacer materials (nylon 6 or nylon 66) are similarly customizable.

30-Day Lead Time – In an industry where long production cycles are common, LDB’s 30-day standard lead time for custom double row ball slewing bearings provides a competitive advantage.

Main Configurations and Customization Options

LDB offers a range of configurations for double row ball slewing bearings.

By Gear Type

No gear (plain) – For applications where rotation is driven externally, such as friction drives or separate pinion systems.
Internal gear – Gear teeth are cut on the inner ring’s inner diameter. Common in wind turbines and other compact installations.
External gear – Gear teeth are cut on the outer ring’s outer diameter. Widely used in concrete pump trucks, cranes, and excavators.

By Ring Material

42CrMo – High-strength alloy steel with excellent toughness and fatigue resistance. Suitable for heavy-duty applications including wind turbines.
50Mn – Medium-carbon manganese steel offering good hardenability and wear resistance.
C45 – Unalloyed medium-carbon steel with reliable mechanical properties.

By Cage and Spacer Material

Cage: Steel 20 (high strength, impact resistant) or ZL112 cast aluminum alloy (lightweight, corrosion resistant)
Spacer: Nylon 6 or nylon 66 – both offer low friction and good wear resistance; nylon 66 provides higher temperature tolerance.

By Ball Material

GCr15 – High-carbon chromium bearing steel. Provides high hardness, excellent wear resistance, and long fatigue life.

Industrial Applications

LDB’s double row ball slewing bearings are deployed across multiple industries, with two primary application areas standing out.

Wind Turbine Equipment – The same-diameter double row ball slewing bearing is installed at the root of the propeller (blade root), acting as a side propeller. This bearing allows the blade to pitch – adjusting its angle relative to the wind – which is essential for controlling rotational speed and optimizing energy capture. The bearing must withstand millions of load cycles over a 20+ year service life, resist environmental corrosion, and maintain precise rotational accuracy. LDB’s double row design, with its eight-point contact geometry and GCr15 balls, is specifically engineered for this demanding duty.

Concrete Pump Trucks – In concrete pump trucks, the slewing bearing is mounted between the chassis and the pump turret, allowing the boom to rotate 360 degrees. Double row ball bearings are preferred here because they must support not only the weight of the extended boom and concrete-filled piping but also the dynamic loads generated by pumping operations and wind forces. The higher load capacity and reliability of double row designs reduce the risk of field failures during concrete pours.

Additional Applications – Beyond these primary uses, LDB’s double row ball slewing bearings are also found in tower cranes, mobile cranes, aerial work platforms, harbor cranes, radar antennas, solar tracking systems, and industrial turntables.

LDB’s Manufacturing Excellence

LDB’s production process is built around precision machining, controlled heat treatment, and rigorous inspection.

Material Sourcing and Verification – Incoming ring materials (42CrMo, 50Mn, C45) and ball materials (GCr15) are verified for chemical composition and mechanical properties. Certificates are maintained for full traceability.

Precision Machining – Ring blanks are rough-turned, then finish-ground on CNC vertical lathes and grinding machines. Raceway profiles are machined to achieve the required geometry for eight-point contact. Gear teeth (if specified) are cut using hobbing or shaping processes.

Heat Treatment – Raceways undergo induction hardening to achieve HRC 55-62, providing a hard, wear-resistant surface while preserving core toughness. The specific heat treatment process is controlled to prevent distortion and maintain dimensional accuracy.

Assembly – Balls (GCr15), cages (steel 20 or ZL112 aluminum alloy), spacers (nylon 6 or nylon 66), and seals are assembled in a clean environment.

Inspection and Testing – Each bearing is tested for rotational torque, radial and axial runout, gear accuracy (if applicable), and raceway hardness. Non-destructive testing methods verify material integrity.

Packaging and Logistics – Finished bearings are coated with anti-corrosion oil and packaged in metal brackets or export-standard fumigation-free wooden boxes, ensuring safe delivery to customers worldwide.

Conclusion

Double row ball slewing bearings occupy a critical position in heavy machinery, offering higher load capacity and greater reliability than single-row alternatives. Luoyang LDB Bearing Co., Ltd. manufactures these components with careful attention to material selection, precision machining, and quality control – as reflected in the specifications of 42CrMo/50Mn/C45 rings, GCr15 balls, HRC 55-62 raceway hardness, and a 30-day lead time for custom orders.

The same-diameter double row ball slewing bearing produced by LDB is particularly well-suited for wind turbine equipment – where it is installed at the propeller root and acts as a side propeller – and for concrete pump trucks, where it enables reliable 360-degree boom rotation. With eight points of contact per ball, two separate raceways, and a wide outer diameter range from 300 mm to 10,000 mm, LDB’s double row ball slewing bearings deliver the performance, durability, and application-specific engineering that modern industries demand.

For clients seeking a trusted manufacturer who understands both the theoretical advantages of double row designs and the practical realities of production, LDB offers a compelling combination of technical capability, material quality, and responsive delivery.

CAT Excavator Slewing Bearing Supplied to South America

April 29, 2026/in LDB Company News /by LDB Bearing

In the field of construction machinery, the quality and timely delivery of slewing rings directly affect the stable operation of host equipment. In November 2021, our company successfully completed a supply task for a CAT excavator slewing ring to a client in South America. This case not only demonstrates our mature capability in supply chain management but also highlights our professional understanding of a specific bearing type: the Four-Point Contact Ball Slewing Bearing.

The slewing ring supplied in this project is of the four-point contact ball type. This bearing features a single raceway design, where each ball contacts the raceway at four distinct points. As a result, it can simultaneously withstand axial loads, radial loads, and tilting moments. Compared to other slewing bearing types, the four-point contact ball design offers higher load efficiency, a more compact cross-section, and good impact resistance. These characteristics make it particularly suitable for excavators and other construction machinery that require frequent slewing and heavy-duty operation.

Caterpillar (CAT), as a globally renowned construction machinery brand, imposes strict requirements on the precision, reliability, and service life of the slewing rings used in its excavators. The client in this case was based in South America, and the equipment was intended for applications such as mining, earthmoving, and infrastructure construction. To ensure stable slewing performance and operational safety under complex combined loads, the client explicitly requested a four-point contact ball slewing bearing.

After order confirmation, our company strictly controlled every stage of production, inspection, and packaging. The slewing rings were manufactured as scheduled and shipped in November 2021 via a dedicated South America logistics route. Each unit underwent a full range of factory tests, including dimensional accuracy, rotational flexibility, hardness, and flaw detection, to confirm compliance with CAT excavator interface and performance standards. For logistics, anti-corrosion treatment and reinforced packaging were applied to prevent damage or rust during long-distance ocean transportation.

Upon arrival at the client’s site in South America, the slewing rings were installed and tested. The customer reported that the four-point contact ball slewing bearing performed excellently in actual excavator operations, demonstrating low friction, high rigidity, and stable rotational accuracy. It effectively reduced slewing noise and vibration, meeting the expected service life requirements under demanding working conditions.

This case of supplying a Four-Point Contact Ball Slewing Bearing for a CAT excavator to a South American client in November 2021 once again proves our company’s professional capability in the field of critical components for construction machinery. From product selection and quality control to international logistics, we are committed to providing efficient and reliable solutions for our customers. We look forward to continuing to support the stable operation of construction equipment worldwide with high-quality slewing rings.

What is a Four Point Contact Ball Slewing Bearing?

How Does a Four Point Contact Ball Slewing Bearing Work?

When loads are applied, the contact points engage as follows:

Pure axial load in one direction: Two of the four contact points become active
Reversed axial load: The opposite pair of contact points engages
Combined loads (axial + radial + tilting moment): All four contact points share the load simultaneously

Key Features of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers a range of distinctive engineering features:

Single-row compact design: Consists of only two seat rings (inner and outer), providing a compact structure with light weight
Four-point contact geometry: Steel balls contact the arc raceway at four points, enabling combined load handling (axial, radial, and tilting moment simultaneously)
Multiple gear options: Available as no gear, internal gear, or external gear to suit various drive configurations
Flexible ring structure: Choice between integral rings (higher rigidity) and split rings (easier adjustment)
Cage or full-ball options: Caged designs for standard applications; full-ball designs for higher load capacity with the trade-off of increased friction
High static load capacity: Engineered to withstand demanding static and dynamic conditions
Wide dimensional range: Outer diameter from 300 mm to 10,000 mm, ball diameter from 30 mm to 75 mm
High load rating: Rated load from 129 kN to 3,410 kN
Fast delivery: Standard lead time of 10–30 days for custom orders

LDB specific features:

Materials: 42CrMo and 50Mn high-grade steel
Seal type: Nitrile rubber for effective contamination protection
Hardness: Normalizing hardness 187-241 HB, quenched and tempered hardness 229-269 HB, raceway quenching hardness HRC 55-62
Inner diameter range: 100 mm to 8,000 mm
Warranty: 12 months

Main Types of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings can be classified based on three main criteria: gear configuration, ring structure, and ball arrangement.

1. By gear configuration:

No gear (plain): For applications where the drive system does not require gear engagement
Internal gear: Gear teeth cut on the inner ring, suitable for compact drive designs where space is limited
External gear: Gear teeth cut on the outer ring, commonly used in excavators, cranes, and turntables

2. By ring structure:

Integral ring design: Higher rigidity, suitable for heavy-duty applications requiring maximum structural integrity
Split ring design: Allows for easier adjustment and maintenance; bolts connect the two split rings before the product leaves the factory

3. By ball arrangement:

Caged design: Standard configuration with spacers or cages to reduce friction and prevent ball-to-ball contact
Full-ball design: No cage or spacer, providing higher load capacity but increased frictional resistance; friction can also easily cause scratches on the surface layer of the steel ball

Core Advantages of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers several distinct advantages over other slewing bearing types:

Combined load capability: Can simultaneously bear axial force, radial force, and tilting moment within a single row, eliminating the need for multiple bearing arrangements
Compact and lightweight: The single-row two-seat-ring design saves space and reduces overall machine weight, making it ideal for mobile equipment
Bidirectional axial load support: Handles thrust loads from both directions without additional raceways or bearings
High static load capacity: Suitable for applications with heavy shock loads and intermittent rotation patterns common in construction machinery
Design flexibility: Customizable gear type (no gear, internal gear, external gear), ring structure (integral or split), and ball arrangement (caged or full-ball) to meet specific requirements
Long service life: Optimized sealing and lubrication options extend operational life, especially in harsh environments
Cost-effective: Lower manufacturing and maintenance costs compared to double-row or cross-roller alternatives
Fast customization: 10–30 day delivery for custom orders enables rapid project execution

LDB product advantages:

This series of slewing ring is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation
Sealing structure and internal fixator can be optimized based on the specific working environment requirements
Both standard and non-standard models available – non-standard models designed and manufactured to customer requirements
Complete sets available without gears, with external gears, with internal gears, or individual ring gears
Secure packaging: metal bracket or export-standard fumigation-free wooden box

Common Applications of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings are widely used across various industries, particularly in construction machinery. Based on LDB’s application scope, common applications include:

Construction and heavy machinery:

Rotary conveyors
Welding robots and manipulators
Small and medium cranes
Excavators (turntable applications)
Aerial work platforms

Other industrial applications:

Solar tracking systems
Wind turbine yaw and pitch systems
Industrial turntables and indexing tables
Medical imaging equipment (CT scanners)
Material handling equipment
Radar and antenna rotators
Packaging machinery

How to Select the Right Four Point Contact Ball Slewing Bearing?

Selecting the correct four point contact ball slewing bearing for your application requires careful consideration of the following factors:

Selection Factor	Considerations
Load requirements	Calculate axial load, radial load, and tilting moment (kN·m). LDB’s rated load range is 129–3,410 kN.
Dimensional constraints	Verify outer diameter (300–10,000 mm), inner diameter (100–8,000 mm), and ball diameter (30–75 mm) fit your mounting space.
Gear configuration	Choose no gear, internal gear, or external gear based on your drive system design.
Ring structure	Select integral ring for higher rigidity or split ring for easier adjustment.
Ball arrangement	Choose caged design for standard applications with lower friction, or full-ball design for higher load capacity (note: full-ball design has higher friction and may cause scratches on steel ball surface).
Operating environment	Consider temperature, dust, moisture, and chemical exposure. LDB uses nitrile rubber seals as standard, with customization available for special environments.
Material and hardness	LDB offers 42CrMo and 50Mn materials with raceway quenching hardness HRC 55-62 for optimal wear resistance.
Precision requirements	Specify required tolerances for your application.
Delivery schedule	LDB standard lead time is 10–30 days for custom orders.
Warranty	LDB offers 12 months warranty on all slewing bearings.

Additional selection tips:

For large axial loads and overturning moments with continuous operation, the single-row four-point contact ball slewing bearing is highly recommended
LDB can optimize sealing structure and internal fixator design based on your specific working environment
Both standard and non-standard models are available – contact LDB for non-standard requirements
Consider the total cost of ownership, including maintenance intervals and expected service life

LDB – Custom Four Point Contact Ball Slewing Bearings Manufacturer

LDB four point contact ball slewing bearing specifications:

Parameter	LDB Range / Value
Brand	LDB (Luoyang Longda)
Outer diameter	300 mm – 10,000 mm
Inner diameter	100 mm – 8,000 mm
Ball diameter	30 mm – 75 mm
Rated load	129 kN – 3,410 kN
Gear type	No gear, internal gear, external gear
Delivery lead time	10 – 30 days
Material	42CrMo, 50Mn
Seal type	Nitrile rubber
Rolling element	Steel ball
Normalizing hardness	187 HB – 241 HB
Quenched and tempered hardness	229 HB – 269 HB
Raceway quenching hardness	HRC 55 – 62
Warranty	12 months
Packaging	Metal bracket or export standard fumigation-free wooden box

LDB product advantages:

Superior design: The single-row four-point contact ball slewing bearing is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation.
Customizable engineering: According to the requirements of the supporting working environment, LDB can optimize the design of the sealing structure and the internal fixator.
Flexible manufacturing: LDB maintains commonly used standard models, and non-standard models can be designed and manufactured according to customer requirements.
Complete solutions: LDB provides complete sets of slewing bearings without gears, with external gears, with internal gears, or individual ring gears according to customer requirements.
Secure packaging: All products are shipped in metal brackets or export-standard fumigation-free wooden boxes to ensure safe delivery.

Why choose LDB?

Experience: Years of expertise in slewing bearing design and manufacturing
Quality: High-grade materials (42CrMo, 50Mn) with precision heat treatment and raceway hardening to HRC 55-62
Customization: Full engineering support for non-standard models
Speed: 10-30 day delivery for custom orders
Warranty: 12 months on all products
Global shipping: Reliable logistics network supporting delivery worldwide

Contact LDB today to discuss your specific four point contact ball slewing bearing requirements．

Precision in Motion: Navigating the Challenges of Slewing Bearings in Vehicle Radar

April 28, 2026/in Bearing Knowledge, Slewing Bearing Knowledge /by LDB Bearing

In the rapidly evolving landscape of autonomous driving, advanced driver-assistance systems (ADAS), and mobile military surveillance, the “eyes” of the vehicle—the radar system—must be both incredibly sharp and incredibly mobile. Whether it is a long-range meteorological radar mounted on a specialized vehicle or a high-frequency tactical scanning unit, the ability to rotate with absolute precision is non-negotiable.

At the center of this rotational capability lies a specialized mechanical component: the Vehicle Radar Slewing Bearing. While often overshadowed by software and sensors, this bearing is the hardware foundation upon which the entire radar’s reliability is built. In this deep-dive exploration, we analyze the unique characteristics, operational mechanics, and significant engineering challenges associated with these specialized components.

What Is a Vehicle Radar Slewing Bearing?

A Vehicle Radar Slewing Bearing (also frequently referred to as a slewing ring or turntable bearing) is a large-diameter, low-profile, high-precision bearing designed specifically to facilitate the controlled rotational movement of a radar antenna, transceiver dish, or protective dome relative to the vehicle’s stationary chassis or pedestal.

Unlike standard industrial bearings that might only support a shaft or a localized load, a slewing bearing acts as a vital structural joint. It must bridge the gap between the vehicle and the sensor, providing both a smooth rotational path and structural stability.

In vehicle applications, these bearings are distinct. They are typically optimized to be “thin-sectioned” to prioritize weight savings without sacrificing structural rigidity. Yet, they must remain robust enough to concurrently manage complex, multi-directional load spectrums: severe axial loads (the dead weight of the radar units), radial loads (centrifugal forces generated during rapid vehicle turning), and significant tilting moments (forces generated by wind resistance against the radar dish or dynamic G-forces). Essentially, it is the sophisticated pivot point that allows the radar to perform flawless 360° continuous scanning, sector scanning, or indexed positioning, ensuring a stable, wobble-free platform for data acquisition.

Key Characteristics for Vehicle Radar Applications

Radar systems mounted on mobile platforms do not operate in the clean, controlled environments of stationary industrial plants. They are exposed to the rigors of the road, battlefield, or open ocean. Consequently, their slewing bearings must possess a specific, highly demanding set of architectural and metallurgical characteristics customized for this harsh environment:

Low Section Height and Lightweight

This is a paramount engineering requirement. In vehicle design, every kilogram matters. Minimizing the weight of the bearing reduces the total vehicle mass, which directly improves fuel/energy consumption and agility. Furthermore, maintaining a “thin-section” profile keeps the total system height down, reducing the vehicle’s center of gravity—critical for stability during high-speed cornering or off-road maneuvers.

Exceptional Rotational and Positioning Accuracy

Any infinitesimal “play,” wobble, or manufacturing deviation within the bearing’s raceway is geometrically amplified over the range of the radar signal. A tiny micro-meter deviation at the bearing center can translate to critical angular errors in target location kilometers away. To ensure maximum data integrity, these bearings are often manufactured to extreme precision grades, such as P5 or even P4, ensuring near-perfect concentricity and minimum runout.

Low and Constant Torque Parameters

The motors driving mobile radar units (often high-performance, compact servo motors) have limited power budgets. A vehicle radar slewing bearing must offer extremely low starting torque to allow the motor to initiate movement without oversizing. Just as importantly, this torque must remain constant throughout the entire 360-degree rotation. Friction “spikes” or “stuttering” would introduce non-linearities that a servo controller would struggle to compensate for, resulting in inaccurate radar positioning and blurred data.

Superior Environmental and Corrosion Resistance

Exposed on rooftops or masts, vehicle radar bearings are at the mercy of the elements. Road salt, mud, extreme humidity, pressurized water from vehicle washing, and varying climates (from desert heat to arctic cold) conspire to degrade the component. The material selection—often involving specialized stainless steels, advanced alloys, or robust surface coatings like zinc-nickel plating—is critical to prevent corrosion that would rapidly destroy the precision raceways.

How Does a Slewing Bearing Work in Vehicle Radar?

The fundamental principle behind the operation of a vehicle radar slewing bearing is its capacity for sophisticated load distribution within a single, integrated component.

The bearing structure traditionally consists of two rings: an inner ring and an outer ring, with a singular or multiple rows of rolling elements (high-precision balls or rollers) captured precisely between them. The geometry of the raceways where these rolling elements glide is the secret to its capability.

Typically, one ring is bolted firmly to the stationary base mounting pedestal of the vehicle, while the other ring is attached directly to the rotating radar antenna structure or its gimbals. As the radar’s dedicated drive system—most commonly a geared motor driving a pinion that meshes with gear teeth integrated directly onto one of the bearing rings—engages, the bearing facilitates a smooth, low-friction glide.

The true engineering genius of the slewing ring, however, is its response to combined loading. Because a radar dish essentially acts as a sail, it generates immense tilting moments, particularly when the vehicle is moving at high speeds or when facing strong headwinds. Standard bearings would struggle under these overturning forces. A vehicle radar slewing bearing uses a specialized raceway design—frequently a “four-point contact” ball configuration. In this design, each ball makes contact with the raceways at four distinct points, allowing a single bearing row to lock the rings together and resist axial pull-apart forces, radial sliding forces, and the pivotal tilting moments, simultaneously and flawlessly.

Why Not Use Ordinary Bearings?

A valid engineering question often arises: Why cannot a standard, off-the-shelf deep-groove ball bearing or a simple tapered roller bearing suffice for this application, particularly if space allows?

The comprehensive answer lies in the dynamic complexity of the load spectrum and the stringent space optimization required by vehicle platforms.

Standard bearings are fundamentally optimized to handle either primarily radial loads (like the main bearing on a car axle) or primarily axial loads (like a thrust washer supporting a vertical shaft). However, a vehicle radar dish almost never experiences a clean, singular load. Its dead weight (axial) is compounded by the lateral G-forces of vehicle movement (radial), and critically, by the overwhelming levered force of wind resistance hitting the dish surface (tilting moment).

Attempting to manage this combined scenario with ordinary bearings would necessitate a cumbersome, multi-bearing design. You would require at least two large bearings spaced significantly apart on a dedicated, heavy-duty central shaft to provide the necessary leverage to counteract the tilting moment. Such a solution is completely antithetical to modern vehicle design; it would consume excessive vertical space, add substantial dead weight, increase inertia (making rapid scanning harder), and complicate the entire drive assembly. A slewing bearing elegantly handles all three complex load types within a single, integrated, low-profile, large-diameter unit, achieving optimization that ordinary bearings simply cannot match.

Challenges of Vehicle Radar Slewing Bearings

Engineering a high-precision rotational joint for a mobile platform is inherently an exercise in managing conflicting performance requirements. The technical hurdles are substantial and require specialized expertise to overcome.

A. The Vibration and Shock (Brinelling) Factor

This is perhaps the most significant structural challenge. Vehicles constantly encounter potholes, uneven off-road terrain, engine vibrations, and, in tactical scenarios, the shock of weapons fire. Standard industrial bearings operate continuously. Paradoxically, radar bearings often spend considerable time stationary while the vehicle is in motion. This constant vibration while the bearing is static can lead to false brinelling (also called friction oxidation). The rolling elements (balls) vibrate micrometrically against the stationary raceway, wearing away the protective lubrication film and creating molecular-level wear (fretting) that results in permanent, microscopic indentations. These indentations later cause noise, vibration, and loss of precision when the bearing finally rotates.

B. Severe and Rapid Temperature Fluctuations

A mobile radar must be operationally ready in all climates. A tactical vehicle might start its day in a $20^{\circ}\text{C}$ controlled environment and rapidly deploy into a $-30^{\circ}\text{C}$ exterior, or operate continuously in harsh desert conditions exceeding $50^{\circ}\text{C}$. These extreme and often rapid temperature shifts cause the steel rings to expand and contract. Engineers face a paradox: If the internal clearance (preload) of the bearing is too tight to maximize rigidity, thermal contraction in the cold will cause the bearing to seize; if it is designed too loose to accommodate thermal expansion, the radar loses precision in warm weather, creating data “wobble.”

C. Electromagnetic Interference (EMI) Sensitivity

Radar systems are inherently sensitive to electrical noise. The mechanical drive system must not introduce interference that degrades the sensor’s signal integrity. Standard metallic bearings and, critically, their chemical lubricants must be non-interfering. This sometimes requires the integration of non-conductive ceramic rolling elements or specialized sealing and grounding systems to isolate the mechanical components electrically from the delicate RF (radio frequency) sensor electronics.

D. Extreme “Fit-and-Forget” Maintenance Constraints

In the field, whether a commercial autonomous fleet or a military deployment, vehicles cannot be easily withdrawn from service for routine mechanical bearing maintenance. Access to a roof-mounted or mast-mounted bearing is often difficult and time-consuming. These components must be engineered as true “fit-and-forget” systems. This places immense pressure on the design of the sealing system and the selection of the grease. The bearing must maintain its lubrication and exclude external contaminants for thousands of hours of operation over many years without manual intervention. catastrophic seal failure, leading to water or particulate ingress, is the single leading cause of bearing failure in the field.

How to Address These Challenges in Slewing Bearing Design and Selection

To overcome this intimidating gauntlet of technical hurdles, specialized design strategies, meticulous material science, and advanced manufacturing processes must be employed during the creation of a vehicle radar slewing bearing.

Preloading for Rigidity and Resistance: By applying a meticulously calculated controlled internal load (preload) during factory assembly, engineers can completely eliminate internal “clearance” or “play.” This ensures that every ball or roller is always firmly engaged with the raceways, even when static. Preloading achieves two vital goals: it maximizes the rotational rigidity (eliminating wobble) and prevents false brinelling by ensuring the rolling elements cannot “chatter” against the raceway under vibration.
Specialized Wide-Temperature Lubrication: Standard greases fail in the arctic or the desert. We utilize advanced synthetic greases specifically formulated with extreme wide-temperature operating windows. These specialized lubricants ensure that the grease film remains viscous enough to protect at high temperatures but doesn’t “stiffen” and exponentially increase starting torque at $-40^{\circ}\text{C}$.
Advanced and Customized Sealing Systems: A simple O-ring is insufficient. High-reliability radar bearings utilize multi-lip seals, labyrinth seals (which use intricate paths rather than contact to exclude dust), or custom-engineered integrated cassette seals. These advanced systems are designed to keep lubricants in while vigorously excluding fine particulate dust, desert sand, and pressurized water, ensuring raceway integrity.
Specialized Metallurgy and Coatings: Standard bearing steel (GCr15) may be insufficient. Specialized stainless steel alloys can be used for inherent corrosion resistance. Alternatively, robust surface treatments like zinc-nickel plating, thin-dense chrome, or even advanced thin-film coatings (like DLC – Diamond-Like Carbon) can provide extreme corrosion resistance and wear reduction without adding the substantial mass and cost associated with solid stainless steel.

Conclusion

The vehicle radar slewing bearing is a masterpiece of precision mechanical engineering, masquerading as a simple industrial part. It represents a deeply optimized fusion of low-weight structural integrity, extreme load-handling capacity, and sub-degree rotational accuracy.

As we accelerate toward a future of fully autonomous transport, sophisticated LiDAR-guided mobility, and ever-more capable mobile defense systems, the demand for these “high-IQ” mechanical joints will only intensify. Selecting the right bearing is not merely a decision about dimensions and gear ratios; it is a critical engineering decision about ensuring that the “eyes” of the vehicle remain flawlessly focused, reliable, and functional in the most punishing environments on Earth.

LDB: Partner for Customized Vehicle Radar Slewing Bearings

When it comes to the highly specialized, zero-failure demands of the vehicle radar and mobile sensor industry, LDB Slewing Bearing stands at the forefront of precision engineering. LDB is an enterprise specializing exclusively in the design, development, manufacture, and global sales of precision slewing bearings and precision slewing drives.

As a dedicated professional slewing ring supplier, we don’t just provide off-the-shelf products; we provide high-performance solutions optimized specifically for the unique environment of vehicle-mounted radar systems, commercial ADAS arrays, and tactical surveillance platforms. We understand that in the world of mobile sensing, a “standard” catalogue part is almost never the optimal part.

Unlike other generic providers of bearings, LDB can offer fully tailored, custom slewing bearing solutions. We collaborate directly with your engineering team, utilizing our expertise to integrate advanced monitoring sensors (for temperature or vibration), robust wide-temperature lubrication systems, and specialized, site-specific sealing systems. Our custom-engineered vehicle radar slewing bearings are built to deliver higher reliability, exceptional positioning accuracy, and a significantly longer service life—crucial for maximizing the uptime of your vehicle fleet or mission-critical sensor array.

Our wide range of expert technical services also helps our clients optimize entire system performance and cut long-term operational costs through precision-targeted, right-sized design. With a strong global presence and technical support, LDB ensures that high-quality, fully customized slewing bearing solutions are delivered quickly to radar projects and production facilities around the world. Partner with LDB to build your technology on a foundation of unyielding precision and reliability. Contact us today to discuss your customized vehicle radar project.

FAQ of Vehicle Radar Slewing Bearing

Here are some of the most common questions from engineers and procurement specialists regarding these specialized rotational components:

Q1: How often should a vehicle radar slewing bearing be re-lubricated in the field?

A: This interval is highly dependent on the operating environment. For vehicles in severe off-road, tactical, or extremely dusty environments, lubrication should be checked and replenished every 200–500 hours of actual rotation. However, this is precisely where custom design makes a difference. LDB specializes in providing fully customized solutions utilizing extreme-duty long-life greases and optimized sealing systems that can exponentially extend these intervals, aiming for “maintenance-free” operation for the practical lifecycle of the radar unit.

Q2: Can LDB manufacture precision slewing bearings that reliably operate in sub-zero arctic environments?

A: Absolutely. Low-temperature performance is one of our key areas of expertise. We utilize specialized metallurgical processes (such as cryogenic treatment) for the steel rings to maintain toughness and combine them with synthetic lubricants specifically engineered to maintain their viscosity and low starting torque at temperatures as low as $-40^{\circ}\text{C}$ or even $-50^{\circ}\text{C}$.

Q3: Why is “backlash” a primary concern for radar and LiDAR slewing bearings?

A: Backlash is the unavoidable “play” or free space between gear teeth or internal rolling elements. In a radar or LiDAR system, even minuscule backlash causes the antenna to “hunt” for its commanded position, vibrate during scanning, or introduce lag. This directly translates to blurred sensor signals, ghost targets, or highly inaccurate angular tracking. LDB precision bearings for this industry utilize optimized preloading and customized gear geometry to minimize backlash, ensuring crystal-clear data acquisition and accurate target lock.

Q4: Do you offer lightweight material options for weight-sensitive autonomous vehicle projects?

A: Yes, weight optimization is central to our design philosphy for this sector. While we predominantly use high-strength bearing steels, we can utilize highly optimized thin-section designs that reduce cross-sectional area and integrate lightweight flanges or aluminum rings (for non-load-bearing components) to maximize the strength-to-weight ratio without sacrificing the rigidity required by the radar sensor.

Q5: What fundamentally makes LDB different from other large slewing ring manufacturers?

A: Our core differentiator is our focus on customization and vertical integration. We don’t just provide a bearing; we provide a rotational system that is fully tailored to your specific application. This means we can integrate custom sealing systems, pre-calculate the precise preload for your vibration environment, and select the exact lubrication strategy for your climate, ensuring your vehicle radar performs reliably in the field where standard components would rapidly fail.

Complete Guide to Slewing Bearings for Tower Garage

April 28, 2026/in Bearing Knowledge, Slewing Bearing Knowledge /by LDB Bearing

As urbanization accelerates, urban planners and developers are increasingly looking upwards for solutions to the chronic shortage of parking spaces. The tower garage (also known as a Vertical Rotary Parking System) has emerged as one of the most efficient automated parking solutions, offering high-density storage on a minimal footprint. While these mechanical marvels appear simple from the outside, their smooth operation depends on sophisticated internal engineering.

At the heart of every high-performance vertical parking system lies a critical mechanical component: the slewing bearing (or Slewing Ring). In this comprehensive guide, we will explore what tower garage slewing bearings are, how they function, and why selecting the right one is paramount for system longevity and safety.

What Is a Slewing Bearing for Tower Garage?

A slewing bearing for tower garage is a large-diameter bearing designed specifically to handle substantial axial loads, radial loads, and massive tilting moments simultaneously, allowing for controlled rotational movement. It acts as the structural pivot point between the stationary base of the tower and the rotating vertical carousel structure.

Unlike traditional bearings designed purely for speed, a slewing bearing is essentially a rotary structural component. In the context of a automated parking system, it is often a large-diameter ring (often exceeding 1.5 meters) with integrated mounting holes and, frequently, an internal or external gear to interface with the driving motor. Its primary definition is to provide a stable, load-bearing platform for complete or partial rotation of the heavy vehicle storage rack.

How Does a Slewing Bearing Work in a Tower Garage?

The principle behind the operation of a automated garage slewing bearing is to facilitate continuous or indexed rotation of the entire vertical parking structure while maintaining absolute structural stability.

The tower parking system works by moving parking carousels vertically like a Ferris wheel, but within a sleek tower. The slewing bearing is positioned at the base (for bottom-driven systems) or sometimes at the top, supporting the central mast or framework around which the carousels travel.

The Functional Role in Operation:

Load Transmission: As the tower rotates to align a specific parking space with the ground-level entry/exit bay, the slewing bearing supports the entire dead weight of the steel structure plus the combined weight of all parked vehicles.
Controlled Rotation: The bearing’s geared teeth (internal or external) mesh with a pinion driven by an electric motor. When the motor activates, the bearing rotates, turning the entire parking structure.
Stability Retention: As cars are loaded and unloaded, the vertical structure experiences Dynamic shifts in load balance, creating powerful tilting moments (overturning forces). The slewing bearing must counteract these forces to prevent the tower from swaying or tilting.

Key Features of Slewing Bearings for Tower Garage Applications

Tower garages are among the most demanding application scenarios for slewing rings. The safety risks are high, and downtime is costly. Consequently, these bearings must possess specific architectural and metallurgical features customized for this environment.

Exceptional Ant-Overturning Capacity: This is the most critical feature. The tall, slender nature of a tower garage means wind loads (if outdoors) and unbalanced loads (more cars on one side) create immense tilting moments. The bearing’s raceway geometry and bolt pattern are designed to keep the structure rigid.
Compact Structural Integrity: Space is at a premium in automated parking. Slewing bearings are inherently compact, offering a low sectional height relative to their diameter. This maximizes useful storage volume within the tower.
High Axial and Radial Load Handling: Beyond moments, they must support sheer downward forces and lateral forces simultaneously.
Reliability Under Static Load: In a automated garage, the bearing spends considerable time stationary (static load) holding a full structure. The raceways must be hardened to prevent Brinelling (permanent indentation) when the system restarts movement.
Smooth, Low-Noise Operation: To make these systems suitable for residential and commercial areas, the bearing must rotate smoothly with minimal noise and vibration. This requires high-precision manufacturing of raceways and gear teeth.

Why Choose a Four-Point Contact Ball Slewing Bearing for Tower Garages?

While multiple types of slewing bearings exist, the single row four-point contact ball slewing bearing is the predominant and often preferred choice for automated parking systems.

The fundamental reason for this choice is efficiency and balance. This specific design features a single row of balls that contact the raceway at four distinct points on the internal and external rings. This unique geometry allows a single bearing ring to manage axial, radial, and moment loads concurrently.

Compared to a crossed roller bearing (which is excellent for rigidity but expensive and sensitive to alignment) or a multi-row roller bearing (which handles higher loads but is much heavier and less compact), the four-point contact ball bearing offers the ideal compromise. It provides sufficient moment rigidity to stabilize the tower, high load capacity for the vehicles, and is a cost-effective solution that simplifies the overall design of the tower’s rotational assembly.

Advantages of Using a Slewing Bearing in Tower Parking Systems

The adoption of robust slewing ring technology is what allows modern automated parking towers to exist. Implementing a high-quality bearing offers several operational and design advantages.

Maximized Parking Efficiency

Because the bearing manages all forces centrally and requires very little height, it allows the parking tower to be taller and more compact. This maximizes the number of vehicles stored per square meter of land.

Enhanced System Longevity

A correctly specified and well-manufactured slewing bearing reduces wear on the driving motor and other mechanical components by ensuring smooth rotation and accurate alignment, extending the entire system’s service life.

Uncompromised Safety

The bearing acts as the foundational dynamic anchor. By resisting overturning moments and dynamic forces during loading cycles, it ensures the stability of the entire automated garage, protecting both the vehicles and the nearby infrastructure.

Improved Operational Speed

Modern slewing rings allow for smooth acceleration and deceleration of the heavy rotating mass, resulting in faster vehicle retrieval times and increased system throughput.

Common Applications of Slewing Bearings in Automated Parking

While our primary focus is the Vertical Rotary or Tower Garage, the principles of slewing bearing technology extend across the spectrum of Automated Parking solutions.

Vertical Carousel Parking (Rotary Parking): The core application discussed here, supporting the dynamic mast of the parking Ferris wheel.
Automated Turntables: Frequently used in garage entrance bays where cars drive in and the entire floor rotates 180 degrees so the driver can exit by driving forward, simplifying vehicle positioning for the main vertical lift.
Horizontal Shuttling Parking Systems: Large-scale systems that use shuttles on multiple levels often utilize small, specialized slewing rings for turning shuttles or maneuvering vehicles in tight spaces within the storage grid.
Puzzle Parking Systems: Used in the lifting or lateral shifting mechanisms of specialized semi-automated systems.

Key Factors to Consider When Selecting a Slewing Bearing for Tower Garage

Selecting the correct slewing ring is not an off-the-shelf procurement; it is a critical engineering decision. The following factors must be analyzed by both the garage manufacturer and the bearing designer.

Load Spectrum Analysis

You must calculate the maximum axial load, radial load, and tilting moment under the worst-case scenario. This includes unevenly distributed loads and maximum system capacity.

Structural Rigidity of the Companion Structure

A slewing bearing’s performance depends heavily on the stiffness of the mounting surface. If the tower base is not rigid enough, it will distort under load, causing uneven load distribution on the bearing balls and leading to premature failure.

Environmental Factors

Will the automated garage be indoors or outdoors? If outdoors, factors like wind load (which massively increases the dynamic moment load), ambient temperature extremes (which affect lubrication viscosity), and moisture (requiring specialized sealing and corrosion resistance) become critical selection parameters.

Gear Type and Precision

Should the bearing have internal or external gears? Internal gears are often preferred in tower garages as they can be protected within the structure. The gear precision class is vital; low precision causes noise, vibration, and gear tooth wear.

How to Maintain Your Tower Garage Slewing Bearing

Maintenance is essential to prevent catastrophic failure in an automated parking system. A systematic approach to maintenance will ensure safety and uptime.

Regular Lubrication: This is paramount. Tower garages operate on a “stop-and-go” basis, which can break the lubrication film. Relubrication schedules should be strict, using high-quality extreme pressure (EP) grease.
Seal Inspection: Check the integrity of the bearing seals regularly. Seals keep lubricants in and contaminants (dirt, water) out. A damaged seal is the fastest route to bearing contamination and subsequent failure.
Bolt Check (Tightness Monitoring): The mounting bolts are the unsung heroes holding the bearing and tower together. Periodically check bolt preload using a torque wrench. Loose bolts allow the bearing to flex, damaging raceways, and can eventually lead to structural failure.
Noise and Vibration Monitoring: Maintenance staff should be trained to recognize any change in the sound signature of the rotation. An increasing grinding noise, clicking, or vibration often indicates raceway damage or gear tooth wear.

Conclusion

The success of a Vertical Rotary or Tower Garage depends directly on the reliability of its foundational rotation system. The slewing bearing is not merely a component; it is a critical safety feature and a performance enabler.

By understanding the unique demands of this application—specifically the need for immense anti-overturning capability—and selecting the appropriate technological solution, such as the single row four-point contact ball bearing, parking garage developers can ensure their projects deliver safe, high-density, and long-lasting parking solutions. Investing in high-precision, customized slewing bearing technology is an investment in the future infrastructure of smart cities.

LDB: Your Custom Slewing Bearing Manufacturer for Tower Garage Projects

In the niche of automated parking system engineering, standardization rarely fits. Every project presents unique load constraints, environmental challenges, and geometric requirements. That is where LDB excels.

As a dedicated manufacturer of high-precision slewing bearings, LDB understands the rigorous demands of vertical shuttling and automated parking towers. We do not just sell bearings; we partner with your engineering team.

Customized Design Capability: We analyze your unique load spectrum and moment calculations to design the ideal raceway profile, ball diameter, and gear specifications tailored specifically for your tower parking system.
Material and Heat Treatment Excellence: We use high-quality certified steel alloys and apply precise induction hardening to the raceways to ensure LDB bearings can withstand static loads without Brinelling and deliver thousands of rotating cycles under dynamic load.
Proven Project Experience: LDB has extensive experience providing geared slewing rings for global automated parking projects. We understand the regulatory safety requirements and durability standards.

Ensure the stability and safety of your Vertical Rotary Garage project. Contact LDB today to speak with our engineering application specialists about a customized slewing bearing solution.

FAQ About Slewing Bearings for Tower Garage

Q: What is the average lifespan of a slewing bearing in a Vertical Rotary Parking system?

With proper specification, high-quality manufacturing, and adherence to maintenance schedules (lubrication, bolt checking), a well-designed slewing bearing can last 10–15 years or more, matching the service life of many mechanical garage components before refurbishment is required.

Q: How do I know if my automated garage slewing bearing needs replacement?

Signs of critical wear include excessive “play” or tilting of the tower mast, consistent grinding or popping noises during rotation, significant metal contamination found in grease samples, or visible damage to gear teeth or raceways.

Q: Why is Brinelling a problem in Vertical Parking Systems?

These systems remain stationary for long periods under full load. If the bearing material is too soft or the load too high, the balls can create permanent indentations in the raceway. When the motor restarts, the balls will “clunk” over these depressions, increasing noise, vibration, and acceleration of wear.

Q: Can LDB replace or upgrade a damaged slewing bearing from another manufacturer in my parking tower?

Yes, LDB specializes in reverse-engineering and custom manufacturing replacement slewing bearings. We can analyze the original bearing, improve the design if necessary, and manufacture a replacement that matches the original footprint while potentially offering superior performance.

XCMG Excavator Slewing Ring Supplied to Asia

April 27, 2026/in LDB Company News /by LDB Bearing

In the field of construction machinery, the quality and timely delivery of slewing rings directly affect the stable operation of host equipment. In March 2023, our company successfully completed a supply task for an XCMG excavator slewing ring to a client in Asia. This case not only demonstrates our mature capability in supply chain management but also highlights our professional understanding of a specific bearing type: the Four-Point Contact Ball Slewing Bearing.

XCMG, as a leading Chinese construction machinery brand, imposes strict requirements on the precision, reliability, and service life of the slewing rings used in its excavators. The client in this case was based in Asia, and the equipment was intended for applications such as earthmoving, mining, and infrastructure construction. To ensure stable slewing performance and operational safety under complex combined loads, the client explicitly requested a four-point contact ball slewing bearing.

After order confirmation, our company strictly controlled every stage of production, inspection, and packaging. The slewing rings were manufactured as scheduled and shipped in March 2023 via a dedicated Asia logistics route. Each unit underwent a full range of factory tests, including dimensional accuracy, rotational flexibility, hardness, and flaw detection, to confirm compliance with XCMG excavator interface and performance standards. For logistics, anti-corrosion treatment and reinforced packaging were applied to prevent damage or rust during long-distance transportation.

Upon arrival at the client’s site in Asia, the slewing rings were installed and tested. The customer reported that the four-point contact ball slewing bearing performed excellently in actual excavator operations, demonstrating low friction, high rigidity, and stable rotational accuracy. It effectively reduced slewing noise and vibration, meeting the expected service life requirements.

This case of supplying a Four-Point Contact Ball Slewing Bearing for an XCMG excavator to an Asian client in March 2023 once again proves our company’s professional capability in the field of critical components for construction machinery. From product selection and quality control to international logistics, we are committed to providing efficient and reliable solutions for our customers. We look forward to continuing to support the stable operation of construction equipment worldwide with high-quality slewing rings.

What is a Four Point Contact Ball Slewing Bearing?

How Does a Four Point Contact Ball Slewing Bearing Work?

When loads are applied, the contact points engage as follows:

Pure axial load in one direction: Two of the four contact points become active
Reversed axial load: The opposite pair of contact points engages
Combined loads (axial + radial + tilting moment): All four contact points share the load simultaneously

Key Features of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers a range of distinctive engineering features:

Single-row compact design: Consists of only two seat rings (inner and outer), providing a compact structure with light weight
Four-point contact geometry: Steel balls contact the arc raceway at four points, enabling combined load handling (axial, radial, and tilting moment simultaneously)
Multiple gear options: Available as no gear, internal gear, or external gear to suit various drive configurations
Flexible ring structure: Choice between integral rings (higher rigidity) and split rings (easier adjustment)
Cage or full-ball options: Caged designs for standard applications; full-ball designs for higher load capacity with the trade-off of increased friction
High static load capacity: Engineered to withstand demanding static and dynamic conditions
Wide dimensional range: Outer diameter from 300 mm to 10,000 mm, ball diameter from 30 mm to 75 mm
High load rating: Rated load from 129 kN to 3,410 kN
Fast delivery: Standard lead time of 10–30 days for custom orders

LDB specific features:

Materials: 42CrMo and 50Mn high-grade steel
Seal type: Nitrile rubber for effective contamination protection
Hardness: Normalizing hardness 187-241 HB, quenched and tempered hardness 229-269 HB, raceway quenching hardness HRC 55-62
Inner diameter range: 100 mm to 8,000 mm
Warranty: 12 months

Main Types of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings can be classified based on three main criteria: gear configuration, ring structure, and ball arrangement.

1. By gear configuration:

No gear (plain): For applications where the drive system does not require gear engagement
Internal gear: Gear teeth cut on the inner ring, suitable for compact drive designs where space is limited
External gear: Gear teeth cut on the outer ring, commonly used in excavators, cranes, and turntables

2. By ring structure:

Integral ring design: Higher rigidity, suitable for heavy-duty applications requiring maximum structural integrity
Split ring design: Allows for easier adjustment and maintenance; bolts connect the two split rings before the product leaves the factory

3. By ball arrangement:

Caged design: Standard configuration with spacers or cages to reduce friction and prevent ball-to-ball contact
Full-ball design: No cage or spacer, providing higher load capacity but increased frictional resistance; friction can also easily cause scratches on the surface layer of the steel ball

Core Advantages of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers several distinct advantages over other slewing bearing types:

Combined load capability: Can simultaneously bear axial force, radial force, and tilting moment within a single row, eliminating the need for multiple bearing arrangements
Compact and lightweight: The single-row two-seat-ring design saves space and reduces overall machine weight, making it ideal for mobile equipment
Bidirectional axial load support: Handles thrust loads from both directions without additional raceways or bearings
High static load capacity: Suitable for applications with heavy shock loads and intermittent rotation patterns common in construction machinery
Design flexibility: Customizable gear type (no gear, internal gear, external gear), ring structure (integral or split), and ball arrangement (caged or full-ball) to meet specific requirements
Long service life: Optimized sealing and lubrication options extend operational life, especially in harsh environments
Cost-effective: Lower manufacturing and maintenance costs compared to double-row or cross-roller alternatives
Fast customization: 10–30 day delivery for custom orders enables rapid project execution

LDB product advantages:

This series of slewing ring is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation
Sealing structure and internal fixator can be optimized based on the specific working environment requirements
Both standard and non-standard models available – non-standard models designed and manufactured to customer requirements
Complete sets available without gears, with external gears, with internal gears, or individual ring gears
Secure packaging: metal bracket or export-standard fumigation-free wooden box

Common Applications of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings are widely used across various industries, particularly in construction machinery. Based on LDB’s application scope, common applications include:

Construction and heavy machinery:

Rotary conveyors
Welding robots and manipulators
Small and medium cranes
Excavators (turntable applications)
Aerial work platforms

Other industrial applications:

Solar tracking systems
Wind turbine yaw and pitch systems
Industrial turntables and indexing tables
Medical imaging equipment (CT scanners)
Material handling equipment
Radar and antenna rotators
Packaging machinery

How to Select the Right Four Point Contact Ball Slewing Bearing?

Selecting the correct four point contact ball slewing bearing for your application requires careful consideration of the following factors:

Selection Factor	Considerations
Load requirements	Calculate axial load, radial load, and tilting moment (kN·m). LDB’s rated load range is 129–3,410 kN.
Dimensional constraints	Verify outer diameter (300–10,000 mm), inner diameter (100–8,000 mm), and ball diameter (30–75 mm) fit your mounting space.
Gear configuration	Choose no gear, internal gear, or external gear based on your drive system design.
Ring structure	Select integral ring for higher rigidity or split ring for easier adjustment.
Ball arrangement	Choose caged design for standard applications with lower friction, or full-ball design for higher load capacity (note: full-ball design has higher friction and may cause scratches on steel ball surface).
Operating environment	Consider temperature, dust, moisture, and chemical exposure. LDB uses nitrile rubber seals as standard, with customization available for special environments.
Material and hardness	LDB offers 42CrMo and 50Mn materials with raceway quenching hardness HRC 55-62 for optimal wear resistance.
Precision requirements	Specify required tolerances for your application.
Delivery schedule	LDB standard lead time is 10–30 days for custom orders.
Warranty	LDB offers 12 months warranty on all slewing bearings.

Additional selection tips:

For large axial loads and overturning moments with continuous operation, the single-row four-point contact ball slewing bearing is highly recommended
LDB can optimize sealing structure and internal fixator design based on your specific working environment
Both standard and non-standard models are available – contact LDB for non-standard requirements
Consider the total cost of ownership, including maintenance intervals and expected service life

LDB – Custom Four Point Contact Ball Slewing Bearings Manufacturer

LDB four point contact ball slewing bearing specifications:

Parameter	LDB Range / Value
Brand	LDB (Luoyang Longda)
Outer diameter	300 mm – 10,000 mm
Inner diameter	100 mm – 8,000 mm
Ball diameter	30 mm – 75 mm
Rated load	129 kN – 3,410 kN
Gear type	No gear, internal gear, external gear
Delivery lead time	10 – 30 days
Material	42CrMo, 50Mn
Seal type	Nitrile rubber
Rolling element	Steel ball
Normalizing hardness	187 HB – 241 HB
Quenched and tempered hardness	229 HB – 269 HB
Raceway quenching hardness	HRC 55 – 62
Warranty	12 months
Packaging	Metal bracket or export standard fumigation-free wooden box

LDB product advantages:

Superior design: The single-row four-point contact ball slewing bearing is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation.
Customizable engineering: According to the requirements of the supporting working environment, LDB can optimize the design of the sealing structure and the internal fixator.
Flexible manufacturing: LDB maintains commonly used standard models, and non-standard models can be designed and manufactured according to customer requirements.
Complete solutions: LDB provides complete sets of slewing bearings without gears, with external gears, with internal gears, or individual ring gears according to customer requirements.
Secure packaging: All products are shipped in metal brackets or export-standard fumigation-free wooden boxes to ensure safe delivery.

Why choose LDB?

Experience: Years of expertise in slewing bearing design and manufacturing
Quality: High-grade materials (42CrMo, 50Mn) with precision heat treatment and raceway hardening to HRC 55-62
Customization: Full engineering support for non-standard models
Speed: 10-30 day delivery for custom orders
Warranty: 12 months on all products
Global shipping: Reliable logistics network supporting delivery worldwide

Contact LDB today to discuss your specific four point contact ball slewing bearing requirements．

Hyundai Excavator Slewing Bearing Shipped to Asia

April 24, 2026/in LDB Company News /by LDB Bearing

In November 2024, LDB successfully delivered a high-performance slewing bearing to an Asian customer for a Hyundai excavator. The product supplied was a four point contact ball slewing bearing, specifically engineered for the demanding turntable applications of modern excavators.

The four point contact ball slewing bearing features a single-row design with a Gothic arch raceway, allowing each steel ball to contact the raceway at four points. This unique geometry enables the bearing to simultaneously support axial loads, radial loads, and tilting moments – exactly what a Hyundai excavator turntable requires during digging, lifting, and slewing operations.

For this Asian customer’s Hyundai excavator, LDB provided a fully customized solution. The bearing was precisely engineered to match the customer’s dimensional and load specifications, ensuring a perfect fit and reliable performance in local job site conditions. The four point contact design offered the compactness and high load capacity needed for continuous excavator operation.

By choosing LDB, the Asian customer received a durable, high-precision four point contact ball slewing bearing that minimizes downtime and extends service life. The November 2024 delivery to Asia demonstrates LDB’s ability to supply quality slewing bearings for major excavator brands like Hyundai, with custom solutions and reliable regional shipping.

What is a Four Point Contact Ball Slewing Bearing?

How Does a Four Point Contact Ball Slewing Bearing Work?

When loads are applied, the contact points engage as follows:

Pure axial load in one direction: Two of the four contact points become active
Reversed axial load: The opposite pair of contact points engages
Combined loads (axial + radial + tilting moment): All four contact points share the load simultaneously

Key Features of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers a range of distinctive engineering features:

Single-row compact design: Consists of only two seat rings (inner and outer), providing a compact structure with light weight
Four-point contact geometry: Steel balls contact the arc raceway at four points, enabling combined load handling (axial, radial, and tilting moment simultaneously)
Multiple gear options: Available as no gear, internal gear, or external gear to suit various drive configurations
Flexible ring structure: Choice between integral rings (higher rigidity) and split rings (easier adjustment)
Cage or full-ball options: Caged designs for standard applications; full-ball designs for higher load capacity with the trade-off of increased friction
High static load capacity: Engineered to withstand demanding static and dynamic conditions
Wide dimensional range: Outer diameter from 300 mm to 10,000 mm, ball diameter from 30 mm to 75 mm
High load rating: Rated load from 129 kN to 3,410 kN
Fast delivery: Standard lead time of 10–30 days for custom orders

LDB specific features:

Materials: 42CrMo and 50Mn high-grade steel
Seal type: Nitrile rubber for effective contamination protection
Hardness: Normalizing hardness 187-241 HB, quenched and tempered hardness 229-269 HB, raceway quenching hardness HRC 55-62
Inner diameter range: 100 mm to 8,000 mm
Warranty: 12 months

Main Types of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings can be classified based on three main criteria: gear configuration, ring structure, and ball arrangement.

1. By gear configuration:

No gear (plain): For applications where the drive system does not require gear engagement
Internal gear: Gear teeth cut on the inner ring, suitable for compact drive designs where space is limited
External gear: Gear teeth cut on the outer ring, commonly used in excavators, cranes, and turntables

2. By ring structure:

Integral ring design: Higher rigidity, suitable for heavy-duty applications requiring maximum structural integrity
Split ring design: Allows for easier adjustment and maintenance; bolts connect the two split rings before the product leaves the factory

3. By ball arrangement:

Caged design: Standard configuration with spacers or cages to reduce friction and prevent ball-to-ball contact
Full-ball design: No cage or spacer, providing higher load capacity but increased frictional resistance; friction can also easily cause scratches on the surface layer of the steel ball

Core Advantages of Four Point Contact Ball Slewing Bearings

The four point contact ball slewing bearing offers several distinct advantages over other slewing bearing types:

Combined load capability: Can simultaneously bear axial force, radial force, and tilting moment within a single row, eliminating the need for multiple bearing arrangements
Compact and lightweight: The single-row two-seat-ring design saves space and reduces overall machine weight, making it ideal for mobile equipment
Bidirectional axial load support: Handles thrust loads from both directions without additional raceways or bearings
High static load capacity: Suitable for applications with heavy shock loads and intermittent rotation patterns common in construction machinery
Design flexibility: Customizable gear type (no gear, internal gear, external gear), ring structure (integral or split), and ball arrangement (caged or full-ball) to meet specific requirements
Long service life: Optimized sealing and lubrication options extend operational life, especially in harsh environments
Cost-effective: Lower manufacturing and maintenance costs compared to double-row or cross-roller alternatives
Fast customization: 10–30 day delivery for custom orders enables rapid project execution

LDB product advantages:

This series of slewing ring is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation
Sealing structure and internal fixator can be optimized based on the specific working environment requirements
Both standard and non-standard models available – non-standard models designed and manufactured to customer requirements
Complete sets available without gears, with external gears, with internal gears, or individual ring gears
Secure packaging: metal bracket or export-standard fumigation-free wooden box

Common Applications of Four Point Contact Ball Slewing Bearings

Four point contact ball slewing bearings are widely used across various industries, particularly in construction machinery. Based on LDB’s application scope, common applications include:

Construction and heavy machinery:

Rotary conveyors
Welding robots and manipulators
Small and medium cranes
Excavators (turntable applications)
Aerial work platforms

Other industrial applications:

Solar tracking systems
Wind turbine yaw and pitch systems
Industrial turntables and indexing tables
Medical imaging equipment (CT scanners)
Material handling equipment
Radar and antenna rotators
Packaging machinery

How to Select the Right Four Point Contact Ball Slewing Bearing?

Selecting the correct four point contact ball slewing bearing for your application requires careful consideration of the following factors:

Selection Factor	Considerations
Load requirements	Calculate axial load, radial load, and tilting moment (kN·m). LDB’s rated load range is 129–3,410 kN.
Dimensional constraints	Verify outer diameter (300–10,000 mm), inner diameter (100–8,000 mm), and ball diameter (30–75 mm) fit your mounting space.
Gear configuration	Choose no gear, internal gear, or external gear based on your drive system design.
Ring structure	Select integral ring for higher rigidity or split ring for easier adjustment.
Ball arrangement	Choose caged design for standard applications with lower friction, or full-ball design for higher load capacity (note: full-ball design has higher friction and may cause scratches on steel ball surface).
Operating environment	Consider temperature, dust, moisture, and chemical exposure. LDB uses nitrile rubber seals as standard, with customization available for special environments.
Material and hardness	LDB offers 42CrMo and 50Mn materials with raceway quenching hardness HRC 55-62 for optimal wear resistance.
Precision requirements	Specify required tolerances for your application.
Delivery schedule	LDB standard lead time is 10–30 days for custom orders.
Warranty	LDB offers 12 months warranty on all slewing bearings.

Additional selection tips:

For large axial loads and overturning moments with continuous operation, the single-row four-point contact ball slewing bearing is highly recommended
LDB can optimize sealing structure and internal fixator design based on your specific working environment
Both standard and non-standard models are available – contact LDB for non-standard requirements
Consider the total cost of ownership, including maintenance intervals and expected service life

LDB – Custom Four Point Contact Ball Slewing Bearings Manufacturer

LDB four point contact ball slewing bearing specifications:

Parameter	LDB Range / Value
Brand	LDB (Luoyang Longda)
Outer diameter	300 mm – 10,000 mm
Inner diameter	100 mm – 8,000 mm
Ball diameter	30 mm – 75 mm
Rated load	129 kN – 3,410 kN
Gear type	No gear, internal gear, external gear
Delivery lead time	10 – 30 days
Material	42CrMo, 50Mn
Seal type	Nitrile rubber
Rolling element	Steel ball
Normalizing hardness	187 HB – 241 HB
Quenched and tempered hardness	229 HB – 269 HB
Raceway quenching hardness	HRC 55 – 62
Warranty	12 months
Packaging	Metal bracket or export standard fumigation-free wooden box

LDB product advantages:

Superior design: The single-row four-point contact ball slewing bearing is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation.
Customizable engineering: According to the requirements of the supporting working environment, LDB can optimize the design of the sealing structure and the internal fixator.
Flexible manufacturing: LDB maintains commonly used standard models, and non-standard models can be designed and manufactured according to customer requirements.
Complete solutions: LDB provides complete sets of slewing bearings without gears, with external gears, with internal gears, or individual ring gears according to customer requirements.
Secure packaging: All products are shipped in metal brackets or export-standard fumigation-free wooden boxes to ensure safe delivery.

Why choose LDB?

Experience: Years of expertise in slewing bearing design and manufacturing
Quality: High-grade materials (42CrMo, 50Mn) with precision heat treatment and raceway hardening to HRC 55-62
Customization: Full engineering support for non-standard models
Speed: 10-30 day delivery for custom orders
Warranty: 12 months on all products
Global shipping: Reliable logistics network supporting delivery worldwide

Contact LDB today to discuss your specific four point contact ball slewing bearing requirements．