What are the accuracy requirements for servo motor bearings and how to adjust them?

The accuracy requirements for servo motor bearings are critical due to their direct impact on the precision and performance of the servo motor. These requirements typically focus on factors such as bearing runout, rigidity, vibration levels, and thermal stability. Here’s an overview of these requirements and how to adjust them.

Servo Motor Bearings Accuracy Requirements

Runout Accuracy

  • Radial Runout: This refers to the deviation in the radial direction when the bearing is rotated. High precision applications demand minimal radial runout.
  • Axial Runout: Similar to radial runout but in the axial direction. Critical for maintaining positional accuracy along the axis of rotation.


  • Servo motors often require bearings that can handle high loads without significant deformation to ensure precise movement and responsiveness.

Vibration Levels

  • Low vibration levels are essential to prevent any adverse effects on the motor’s accuracy and to ensure smooth operation.

Thermal Stability

  • Bearings should maintain performance under varying temperatures, as thermal expansion can affect accuracy.

Adjusting Bearings for Servo Motors

Proper Installation

  • Ensure the bearing is properly seated and aligned during installation. Misalignment can lead to increased runout and reduced accuracy.
  • Use precise mounting techniques to avoid any deformation of the bearing rings.

Preload Adjustment

  • Adjusting the preload can help achieve the desired rigidity and reduce play in the bearings. Too much preload can increase friction and wear, while too little can cause excessive play and vibration.
  • Preload can be applied using spring mechanisms, spacers, or controlled axial force during assembly.

Balancing the Rotating Assembly

  • Balance the rotor and the bearing assembly to reduce vibrations. Imbalances can lead to increased vibration levels and reduced accuracy.


  • Use the correct type and amount of lubrication. Over-lubrication can cause excess drag, while under-lubrication can lead to increased wear and noise.

Temperature Management

  • Implement cooling mechanisms or use materials and lubricants that can handle the operating temperature range to maintain thermal stability.
  • Monitor the bearing temperature during operation to ensure it stays within the desired range.

Regular Maintenance

  • Periodically inspect the bearings for signs of wear, contamination, or damage. Regular maintenance helps ensure the bearings remain within the required accuracy specifications.

Precision Bearings

  • Use high-precision bearings designed specifically for servo applications. These bearings are manufactured to tighter tolerances and provide better accuracy and performance.

H70-2RZ C/P4


To ensure servo motor bearings meet the required accuracy:

Focus on minimizing radial and axial runout.

Ensure high rigidity and low vibration levels.

Maintain thermal stability with appropriate lubrication and cooling.

Adjust preload accurately and balance the rotating assembly.

Regularly inspect and maintain the bearings.

By following these guidelines, the performance and accuracy of servo motors can be optimized, leading to improved precision in their applications.