NSK bearing selection

The number of application for NSK rolling bearings is almost countless and the operating conditions and enviroments also vary greatly. In addition, the diversity of operating conditions and NSK bearing requirements continue to grow with the rapid advancement of technology. Therefore, it is necessary to study bearings carefully from many angles to select the best one from the thousands of types and sizes available.

Usually, a NSK bearing type is provisionally chossed considering the operating conditions, mounting arrangement, ease of mounting in the machine, allowable space, cost, availability, and other factors.

Then the size of the NSK bearing is chosen to satisfy the desired life requirement. When doing this, in addition to fatigue life, it is necessary to consider grease life, noise and vibration, wear, and other factors.

There is no fixed procedure for selecting NSK bearings. It is good to investigate experience with similar applications and studies relevant to any special requirements for your specific application.

The following steps show an example of NSK bearing selection procedure.


  • Operating conditions and required performance
  • Environmental conditions
  • Dimensions of shaft and housing


2, Determination of NSK bearing type and mounting arrangement

  • Allowable space
  • Magnitude and direction of loads
  • Vibration and shock
  • Operating speed, maximum speed
  • Misalignment of inner and outer rings
  • Fixing in axial direction and mounting arrangement
  • Ease of bearing mounting and dismounting
  • Sound and torque
  • Required rigidity
  • Availability and cost


3, Determination of NSK bearing size

  • Expected life of machine
  • Dynamic and static equivalent lads
  • Speed
  • Permissible static load factor
  • Permissible axial loads (in the case of Cylindrical roller bearings)


4, Selection of NSK bearing accuracy class

  • Running accuracy
  • Rotational stability
  • Torque fluctuation


5, Determination of internal clearance

  • Fitting
  • Difference in temperature between inner and outer rings
  • Speed
  • Misalignment of inner and outer rings
  • Amount of preload


6, Selection of cage type and material

  • Speed
  • Noise
  • Operating temperature
  • External vibration and shock
  • Rapid acceleration and deceleration
  • Moment load and misalignment


7, Selection of special material, heat treatment for dimensional stability

  • Operating temperature
  • Environment (seawater, vacuum, gases, chemicals, etc.
  • Type of lubrication


8, Selection of lubricating method, lubricant, and type of seals

  • Operating temperature range
  • Speed
  • Lubricating methods
  • Type of seals
  • Maintenance and inspection intervlas


9, Determination of dimensions affecting mounting and procedure for mounting/dismounting

  • Procedure for mounting and dismounting
  • Necessary equipment
  • Dimensions affecting mounting.