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Delivery of Komatsu Excavator Slewing Ring 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 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:

  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．

Hyundai Excavator Slewing Bearing Shipped to Asia

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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?

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．

Caterpillar excavator slewing bearings shipped to Europe

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In December 2025, LDB Slewing Bearing successfully delivered a customized four point contact ball slewing bearing to a European customer for use on a Caterpillar excavator. The customer required a high-performance slewing ring capable of handling heavy combined loads, harsh operating conditions, and demanding duty cycles.

LDB provided a fully tailored four point contact ball slewing bearing designed specifically for the excavator’s turntable application. Unlike standard solutions, LDB integrated advanced monitoring, lubrication, and sealing systems into the bearing, significantly enhancing reliability and extending service life. The four point contact design allowed the bearing to simultaneously support axial loads, radial loads, and tilting moments in a compact single-row configuration, making it ideal for the space-constrained excavator turntable.

Thanks to LDB’s global logistics network, the bearing was delivered on time to Europe in December 2025. Beyond the product itself, LDB’s expert services helped the customer optimize performance and reduce overall costs. This case demonstrates LDB’s capability as a professional supplier of high-quality four point contact ball slewing bearings for demanding heavy equipment applications worldwide.

What is a Four Point Contact Ball Slewing Bearing?

A four point contact ball slewing bearing is a single-row, angular contact ball bearing designed to accommodate simultaneous axial loads, radial loads, and tilting moments.

Unlike standard ball bearings where each ball contacts the raceway at two points, the raceway profile in this design—typically a Gothic arch or double-circular arc—creates four distinct contact points between each ball and the raceways. Two contact points are on the inner ring and two on the outer ring.

This unique geometry allows a single bearing to function like a combination of a thrust bearing and a radial bearing, eliminating the need for multiple bearing rows in many applications. The contact angle is usually 45 degrees, providing an optimal balance between axial and radial load capacity. When pure axial load is applied, all four contact points engage. Under tilting moment or radial load, the contact points redistribute dynamically, maintaining stability and rigidity.

Basic Structure of Four Point Contact Ball Slewing Bearing

The inner and outer rings are typically made of medium-carbon steel such as 42CrMo4 or 50Mn, quenched and tempered to achieve surface hardness of 55-62 HRC on the raceways while maintaining a tough core. One ring usually incorporates either internal or external gear teeth for drive integration, with gear modules typically ranging from 3 to 20 depending on load and drive torque requirements.

A single row of hardened chrome steel balls (typically GCr15 or equivalent) serves as the rolling elements. Ball diameters commonly range from 12.7 mm to 50.8 mm, with larger diameters used for higher load capacities.

The raceways are precision-ground Gothic arch profiles. The radius of each raceway arc is slightly larger than the ball radius, typically by a factor of 0.52 to 0.53 times the ball diameter. This geometric relationship ensures four distinct contact points while minimizing sliding friction.

To prevent ball-to-ball contact and reduce friction, either solid cages or individual spacers are used. Solid cages offer better guidance at higher rotational speeds, while spacers are more common in larger-diameter, slow-rotation applications.

Lip seals, often made of nitrile rubber (NBR) or fluorocarbon (FKM), are pressed into grooves on both rings to prevent ingress of contaminants such as dust, water, and abrasives. Grease nipples are installed at regular intervals around the ring circumference to allow periodic relubrication without disassembly.

Key Features of Four Point Contact Ball Slewing Bearing

The most distinctive feature is the ability to simultaneously support axial loads (both directions), radial loads, and tilting moments in a single row. Static axial load factors (fa) typically range from 1.0 to 1.5, while radial load factors (fr) range from 1.5 to 2.5 depending on the contact angle design.

Because only one row of balls is used, the overall height of the bearing is significantly lower than double-row or three-row designs, saving valuable axial space in equipment design.

The four-point contact configuration distributes loads across multiple points, increasing the load-carrying capacity relative to bearing volume. Static load ratings (C0) for common sizes range from several hundred kN to over 10,000 kN.

The optimized ball-to-raceway contact geometry results in lower friction compared to cross-roller or double-row designs. Starting torque can be as low as 0.02 to 0.05 times the bearing diameter in meters multiplied by the axial load in kN.

Unlike standard angular contact bearings that support axial load in only one direction, the four-point design handles axial thrust from either direction without requiring a second bearing. The bearing is also available with internal teeth, external teeth, or no teeth, allowing flexible integration with pinion drives, worm gears, or direct drive systems.

Applications of Four Point Contact Ball Slewing Bearing

In construction and material handling, these bearings are widely used in excavators (turntable connections between upper and lower frames), mobile cranes, tower cranes, concrete pumps, and aerial work platforms. In excavators specifically, these bearings must survive high shock loads, contamination from dust and debris, and often irregular lubrication schedules.

In renewable energy, they serve in wind turbine pitch and yaw systems, where the bearing must operate reliably for 20+ years with minimal maintenance, as well as solar tracking systems, where slow oscillation and exposure to weather demand good sealing and corrosion resistance.

In industrial automation, they are found in robotic positioning tables, palletizers, and rotary indexers, where precision and low runout (often below 0.05 mm) are critical.

Medical equipment such as large CT scanner gantries, patient positioning tables, and radiation therapy equipment also rely on these bearings, with additional requirements for quiet operation and smooth motion.

In defense and aerospace, they are used in radar antenna mounts, missile launcher turntables, and vehicle turrets, where reliability under extreme conditions is non-negotiable.

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

Define the load spectrum. Gather the complete load history including axial load (Fa), radial load (Fr), and tilting moment (Mk). For rotating applications, also note rotational speed and duty cycle.

Calculate the equivalent static load. Use the formula: Foa = Fa + (2.05 × Fr) + (4.05 × Mk / DL), where DL is the ball pitch circle diameter in meters. The safety factor S0 = C0 / Foa should be at least 1.5 for dynamic applications.

Select gear type and module. Choose internal or external gearing based on your drive layout. Gear module typically ranges from 3 to 12 for construction equipment.

Define the mounting interface. Ensure bolt circle diameter, bolt size and pattern match your flange. Flange flatness should be within 0.05 mm per meter.

Specify clearance and preload. Choose normal clearance for most applications, reduced clearance for higher rigidity, or preload for zero-play requirements.

Choose sealing and lubrication. Select single lip seals for clean environments, double lip for dusty conditions, or labyrinth for extreme contamination. Use lithium-complex grease for -20°C to +120°C range.

Evaluate corrosion protection. For outdoor or marine applications, consider zinc phosphate coating, epoxy paint, or stainless steel rings depending on severity.

Validate with supplier support. Share your load data and operating conditions with your bearing supplier for final verification.

LDB: High Quality Four Point Contact Ball Slewing Bearing Supplier

LDB Slewing Bearing is a specialized enterprise focused on the design, development, manufacture, and sales of precision slewing bearings and precision slewing drives. Unlike mass producers who offer only standardized catalog products, LDB positions itself as an engineering partner capable of delivering fully customized four point contact ball slewing bearings tailored to specific application requirements.

When you choose LDB, you are not just buying a bearing—you are gaining a reliable engineering partner. Our global logistics network guarantees on-time delivery to Europe and beyond, while our expert technical support helps you optimize performance and reduce costs. Whether you need a standard four point contact ball slewing bearing or a fully integrated solution, LDB delivers quality, precision, and value.

Contact LDB today for your next project.