Slewing Bearing for Komatsu Excavator – Shipment to South America
In January 2025, our company successfully shipped a batch of slewing bearings to a South American client for use on Komatsu excavators. The product supplied was our Four Point Contact Ball Slewing Bearing, which is ideal for excavator applications due to its ability to handle axial, radial, and tilting moments simultaneously within a compact structure.
Given the long sea freight to South America, each bearing received anti-corrosion treatment and was packed in reinforced wooden crates to ensure safe transit. The shipment departed in early January 2025 and arrived as scheduled, with all documentation prepared in both English and Spanish for smooth customs clearance.
Upon arrival, the client confirmed that the Four Point Contact Ball Slewing Bearing perfectly matched the Komatsu excavator’s mounting interface and dimensional specifications. Field testing showed smooth rotation with no abnormal clearance or noise, and reliable performance under load. The customer expressed full satisfaction with both product quality and on-time delivery, and noted that our bearing met all expected service life and precision requirements.
What are Four Point Contact Ball Slewing Bearings?
Four point contact ball slewing bearings, also known as four-point contact spherical slewing bearings, are heavy-duty rotating components designed to support large structures while enabling smooth rotational movement. These bearings are widely used in construction machinery, material handling equipment, and industrial automation systems.
A four-point contact ball slewing bearing is mainly 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. The integral ring offers strong rigidity, while the split design allows for easier adjustment. For split structures, bolts are used to connect the two split rings before the product leaves the factory.
Most four-point contact ball slewing bearings are equipped with cages or spacers. However, a full-ball structure is adopted when the load requirements are relatively high. The full-ball configuration provides larger bearing capacity but comes with greater frictional resistance, which may cause surface scratches on the steel balls under certain conditions.
How Does a Four Point Contact Ball Slewing Bearing Work?
The working principle of a four-point contact ball slewing bearing is based on the unique geometry of its raceways. As the name suggests, each steel ball makes contact with the raceway at four distinct points – two on the inner ring and two on the outer ring. This four-point contact configuration enables the bearing to simultaneously handle three types of loads: axial forces (both directions), radial forces, and tilting moments.
Unlike traditional ball bearings that typically contact at two points, the four-point design allows a single row of balls to perform functions that would otherwise require multiple rows. This makes the bearing exceptionally efficient in terms of space utilization and load distribution. When an external load is applied, the contact points transfer forces through the steel balls to the raceways, distributing stress evenly and minimizing localized wear.
Structural Features of Four Point Contact Ball Slewing Bearings
The structural design of four-point contact ball slewing bearings is characterized by compactness and lightweight construction. A single-row four-point contact ball slewing bearing consists of two seat rings, which together form a complete yet space-saving assembly.
Key structural parameters from LDB:
- Outer diameter range: 200mm – 10,000mm
- Inner diameter range: 100mm – 8,000mm
- Ball diameter range: 30mm – 75mm
- Rated load capacity: 129kN – 3,410kN
Material specifications:
LDB manufactures these bearings using high-quality 42CrMo or 50Mn steel. The normalizing hardness reaches 187HB–241HB, while quenched and tempered hardness ranges from 229HB–269HB. The raceway quenching hardness is strictly controlled at HRC 55–62, ensuring excellent wear resistance and long service life.
Sealing and protection:
Nitrile rubber seals are standard, providing effective protection against dust, moisture, and other contaminants. Based on specific operating environments, LDB can optimize the sealing structure and internal fixator design to enhance bearing reliability.
Main Configuration Types of Four-Point Contact Spherical Slewing Bearings
Four-point contact spherical slewing bearings are available in three main configuration types based on gear arrangement:
External Gear Type: The gear teeth are machined on the outer circumference of the outer ring. This configuration is suitable for applications where the driving pinion is located outside the bearing. External gear types are commonly used when space constraints favor an externally mounted drive mechanism.
Internal Gear Type: The gear teeth are machined on the inner circumference of the inner ring. The driving pinion is positioned inside the bearing, resulting in a more compact and visually clean overall assembly. This type is widely preferred for applications with limited external space.
Gearless Type: No gear teeth are present on either the inner or outer ring. This configuration is used in applications where active rotational drive is not required, such as passive follow-up mechanisms or structures that only need relative rotation without powered motion.
All three gear types can be customized according to customer requirements, including special tooth profiles and precision grades.
Core Advantages of Four-Point Contact Spherical Slewing Bearings
Four-point contact spherical slewing bearings offer several distinct advantages:
Compact Structure and Light Weight: The single-row design minimizes axial height and overall weight while maintaining high load capacity. This is particularly beneficial for mobile equipment where weight reduction is critical.
Multi-Directional Load Capacity: The ability to simultaneously bear axial forces (in both directions), radial forces, and tilting moments makes these bearings highly versatile. A single bearing can replace more complex multi-bearing arrangements.
High Static Load Capacity: With optimized raceway geometry and high-quality steel balls, these bearings deliver excellent static load performance, making them suitable for applications with intermittent rotation or heavy shock loads.
Customization Flexibility: LDB offers both standard and non-standard models. Non-standard designs can be manufactured according to specific customer drawings and requirements. The company also provides complete slewing bearing assemblies without gears, with external gears, with internal gears, or individual ring gears as needed.
Reliable Delivery: Standard delivery time ranges from 10 to 30 days, depending on specification complexity and order quantity.
Common Applications of Four-Point Contact Spherical Slewing Bearings
These bearings are widely used across various industries, particularly in construction machinery. Typical applications include:
- Rotary conveyors and turntables
- Welding robots and manipulators
- Small and medium-sized cranes
- Excavators (including Komatsu excavators)
- Aerial work platforms
- Wind turbines (yaw and pitch systems)
- Solar tracking systems
- Medical imaging equipment
- Radar and antenna positioning systems
For each application, LDB can optimize the bearing design – including sealing structure and internal fixator – based on the specific working environment and operational requirements.
Key Factors When Choosing a Four Point Contact Ball Slewing Bearing
When selecting a four-point contact ball slewing bearing for your application, consider the following factors:
Load Requirements: Calculate the maximum axial load, radial load, and tilting moment that the bearing will encounter during operation. Ensure the selected bearing’s rated load capacity meets or exceeds these values.
Gear Configuration: Decide whether external gear, internal gear, or gearless type best suits your drive system layout and space constraints.
Mounting Interface: Verify that the bearing’s inner and outer diameter dimensions match your equipment’s mounting structure. LDB offers outer diameters from 200mm to 10,000mm to accommodate various equipment sizes.
Environmental Conditions: Consider exposure to dust, moisture, temperature extremes, or corrosive substances. Nitrile rubber seals provide basic protection, while optimized sealing designs are available for harsh environments.
Precision and Hardness Requirements: Raceway quenching hardness (HRC 55–62 from LDB) directly affects wear life. Higher hardness generally provides longer service life but may require more precise manufacturing control.
Lead Time and Warranty: LDB offers a 12-month warranty and delivery times of 10–30 days, providing both quality assurance and supply chain reliability.
LDB – Custom Four Point Contact Ball Slewing Bearings Manufacturer
LDB is a professional manufacturer specializing in four-point contact ball slewing bearings and other slewing ring products. The company maintains a comprehensive inventory of standard models while offering full design and manufacturing capabilities for non-standard specifications.
Quality Assurance:
All bearings are manufactured under strict quality control procedures. Each product undergoes dimensional inspection, hardness testing, and functional verification before leaving the factory. The 12-month warranty reflects LDB’s confidence in product durability.
Packaging and Logistics:
Finished bearings are packaged using metal brackets or export-standard fumigation-free wooden boxes to ensure safe transportation. For international shipments, all necessary documentation is prepared to facilitate smooth customs clearance.
Customization Services:
LDB accepts custom orders based on customer drawings and technical requirements. Whether you need special gear profiles, alternative sealing materials, or non-standard dimensional configurations, LDB’s engineering team can provide optimized solutions.
Contact Information:
For inquiries regarding four-point contact spherical slewing bearings – including external gear, internal gear, or gearless types – please contact LDB’s technical sales team with your load specifications, dimensional requirements, and application details.
