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Delivery of Doosan Excavator Slewing Bearing to South America

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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.

CAT Excavator Slewing Bearing Supplied to South America

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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?

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:

  1. This series of slewing ring is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation
  2. Sealing structure and internal fixator can be optimized based on the specific working environment requirements
  3. Both standard and non-standard models available – non-standard models designed and manufactured to customer requirements
  4. Complete sets available without gears, with external gears, with internal gears, or individual ring gears
  5. 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 FactorConsiderations
Load requirementsCalculate axial load, radial load, and tilting moment (kN·m). LDB’s rated load range is 129–3,410 kN.
Dimensional constraintsVerify outer diameter (300–10,000 mm), inner diameter (100–8,000 mm), and ball diameter (30–75 mm) fit your mounting space.
Gear configurationChoose no gear, internal gear, or external gear based on your drive system design.
Ring structureSelect integral ring for higher rigidity or split ring for easier adjustment.
Ball arrangementChoose 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 environmentConsider temperature, dust, moisture, and chemical exposure. LDB uses nitrile rubber seals as standard, with customization available for special environments.
Material and hardnessLDB offers 42CrMo and 50Mn materials with raceway quenching hardness HRC 55-62 for optimal wear resistance.
Precision requirementsSpecify required tolerances for your application.
Delivery scheduleLDB standard lead time is 10–30 days for custom orders.
WarrantyLDB 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:

ParameterLDB Range / Value
BrandLDB (Luoyang Longda)
Outer diameter300 mm – 10,000 mm
Inner diameter100 mm – 8,000 mm
Ball diameter30 mm – 75 mm
Rated load129 kN – 3,410 kN
Gear typeNo gear, internal gear, external gear
Delivery lead time10 – 30 days
Material42CrMo, 50Mn
Seal typeNitrile rubber
Rolling elementSteel ball
Normalizing hardness187 HB – 241 HB
Quenched and tempered hardness229 HB – 269 HB
Raceway quenching hardnessHRC 55 – 62
Warranty12 months
PackagingMetal bracket or export standard fumigation-free wooden box

LDB product advantages:

  1. 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.
  2. Customizable engineering: According to the requirements of the supporting working environment, LDB can optimize the design of the sealing structure and the internal fixator.
  3. Flexible manufacturing: LDB maintains commonly used standard models, and non-standard models can be designed and manufactured according to customer requirements.
  4. 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.
  5. 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．


XCMG Excavator Slewing Ring Supplied to Asia

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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.

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.

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?

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:

  1. This series of slewing ring is suitable for main engines requiring large axial load, high overturning moment, long service life, and continuous operation
  2. Sealing structure and internal fixator can be optimized based on the specific working environment requirements
  3. Both standard and non-standard models available – non-standard models designed and manufactured to customer requirements
  4. Complete sets available without gears, with external gears, with internal gears, or individual ring gears
  5. 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 FactorConsiderations
Load requirementsCalculate axial load, radial load, and tilting moment (kN·m). LDB’s rated load range is 129–3,410 kN.
Dimensional constraintsVerify outer diameter (300–10,000 mm), inner diameter (100–8,000 mm), and ball diameter (30–75 mm) fit your mounting space.
Gear configurationChoose no gear, internal gear, or external gear based on your drive system design.
Ring structureSelect integral ring for higher rigidity or split ring for easier adjustment.
Ball arrangementChoose 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 environmentConsider temperature, dust, moisture, and chemical exposure. LDB uses nitrile rubber seals as standard, with customization available for special environments.
Material and hardnessLDB offers 42CrMo and 50Mn materials with raceway quenching hardness HRC 55-62 for optimal wear resistance.
Precision requirementsSpecify required tolerances for your application.
Delivery scheduleLDB standard lead time is 10–30 days for custom orders.
WarrantyLDB 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:

ParameterLDB Range / Value
BrandLDB (Luoyang Longda)
Outer diameter300 mm – 10,000 mm
Inner diameter100 mm – 8,000 mm
Ball diameter30 mm – 75 mm
Rated load129 kN – 3,410 kN
Gear typeNo gear, internal gear, external gear
Delivery lead time10 – 30 days
Material42CrMo, 50Mn
Seal typeNitrile rubber
Rolling elementSteel ball
Normalizing hardness187 HB – 241 HB
Quenched and tempered hardness229 HB – 269 HB
Raceway quenching hardnessHRC 55 – 62
Warranty12 months
PackagingMetal bracket or export standard fumigation-free wooden box

LDB product advantages:

  1. 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.
  2. Customizable engineering: According to the requirements of the supporting working environment, LDB can optimize the design of the sealing structure and the internal fixator.
  3. Flexible manufacturing: LDB maintains commonly used standard models, and non-standard models can be designed and manufactured according to customer requirements.
  4. 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.
  5. 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．