The radial (axial) clearance of the bearing is the radial (axial) distance from one radial (axial) limit position to the opposite limit position when the bearing has no external load. In reality, because of the shape error of the ferrule and the inconsistency of the rolling body, it should adopt the average value of the radial (axial) displacement in different directions of the ferrule and different relative positions of the ferrule and the rolling body.


Clearance is an important technical parameter of bearing, which directly affects the technical performance of bearing, such as load distribution, vibration, noise, friction, temperature rise, service life and mechanical operation accuracy. Too large clearance will reduce the bearing area inside the bearing, increase the contact surface stress, and shorten the service life.

If the clearance is too large, the bearing area will be reduced and the contact surface stress will be increased, so the service life will be shortened. Too large clearance will reduce the running accuracy of the bearing and increase the vibration and noise. If the clearance is too small, the negative clearance (interference) may appear in the actual operation, which will increase the friction heat and temperature rise, and then make the effective clearance smaller or interference larger. Such a vicious cycle will lead to the locking of the bearing.