Instructions of Clearance

The importance of right clearance

The radial (lateral) internal clearance of a bearing is a radial (lateral) movement of a ring relative to another ring from a radial (lateral) limited position to the opposite limited position. In practice because of the roundness error of rings and the nonidentity of rollers, an average movement should be taken in various directions of a ring and at various relative positions between rings and rollers.

Clearance is an important parameter of a bearing that directly effects the load distribution in a bearing as well as its performances such as vibration, noise, friction resistance, temperature raise, service life, rotation accuracy, etc. Excessive clearance could decrease the loading area in a bearing, increase the stress of contacting surfaces and therefore shorten its life. In addition excessive clearance could also cause worse motion accuracy and increasing vibration and noise. Insufficient clearance may become negative clearance (i.e. interference) in running time, consequently more heat is generated, the temperature is raised, and the effective clearance become further negative, like as in a vicious circle, finally the bearing lead to unable to rotate.