Delivery of Doosan Excavator Slewing Bearing to South America
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.
