How to select four-point contact ball bearings

Four-point contact ball bearings are radial single row angular contact ball bearings designed to support axial loads in both directions. They can support a certain degree of radial loads and take up significantly less axial space than double row bearings. The inner ring is a split inner ring, which allows a higher number of balls to be loaded and increases the load carrying capacity. Selecting a four-point contact ball bearing involves considering several key factors to ensure it suits the specific application.

Four-point contact ball bearing selection

1. Load Type and Magnitude

Axial Load: Four-point contact ball bearings can handle both radial and axial loads. Ensure that the bearing’s axial load capacity meets the application’s requirements.

Radial Load: Determine the radial load the bearing will be subjected to. Four-point contact ball bearings typically have a lower radial load capacity compared to other ball bearings, so this needs to be considered.

Combined Loads: Four-point contact bearings are particularly useful in applications where both radial and axial loads are present. Make sure to calculate and consider the resulting combined load.

2. Bearing Size and Internal Geometry

Bearing Diameter: The size of the bearing should match the shaft diameter or housing in which it will be installed.

Contact Angle: Four-point contact bearings have a contact angle of about 35° that allows them to support both axial and radial loads. Check if this angle aligns with your application’s needs.

Clearance or Preload: This defines the amount of internal clearance between the rolling elements and raceways, which influences the bearing’s performance under load.

3. Speed Requirements

Rotational Speed: Four-point contact bearings are generally suitable for moderate to high-speed operations, but you should verify the maximum speed the bearing can handle by checking the manufacturer's catalog.

Lubrication: High-speed applications may require special lubrication (oil or grease). Make sure to select a bearing that is compatible with the lubrication type you plan to use.

4. Environmental Conditions

Temperature: Consider the operating temperature range. Some four-point contact ball bearings are available with seals or shields for dust, moisture, and temperature resistance.

Corrosion Resistance: If the bearing will be exposed to corrosive environments (e.g., chemicals or water), choose a bearing with appropriate material coatings, such as stainless steel or ceramic bearings.

5. Precision Requirements

Radial Runout and Axial Runout: For high-precision applications, the bearing’s radial and axial runout tolerances should be evaluated.

6. Mounting and Assembly

Housing and Shaft Compatibility: Make sure the bearing fits into the housing and shaft correctly. Pay attention to the shaft and housing tolerances and whether they match the bearing's specifications.

Assembly Considerations: Four-point contact ball bearings can sometimes be more difficult to assemble due to the design of the bearing, so consider ease of installation.

7. Cost vs. Performance

Budget: High-quality four-point contact bearings can be expensive, so balance the performance requirements with your budget. Premium bearings may provide better durability and lower friction, but you may need to justify the investment based on the application's performance.

8. Manufacturer Recommendations

Technical Support: Consult with the manufacturer or a bearing supplier for guidance specific to your application. Manufacturers can assist with selecting the right bearing based on load, speed, and operational conditions.

9. Vibration and Noise Considerations

Noise and Vibration: Four-point contact bearings can produce noise and vibrations under certain operating conditions, especially if there is misalignment. If the application requires low noise or vibration, choose bearings designed to reduce these factors.

Summary Checklist:

Load Type and Magnitude – Ensure the bearing can handle both radial and axial loads.

Bearing Size and Contact Geometry – Choose based on required fit and performance.

Speed and Lubrication – Ensure compatibility with speed and lubrication conditions.

Environmental Conditions – Choose bearings that can withstand temperature, moisture, and corrosion.

Precision – Select an accuracy grade suitable for your application.

Cost vs. Performance – Balance the cost with the required performance and durability.

By considering these factors, you can ensure that you select the most appropriate four-point contact ball bearing for your application.