With the development of industrialization, bearings are used widely in various equipment. The adjustment and measurement of bearing clearance are one of important links in the use of bearings. This article will briefly introduce the classification of bearing clearance.

There is a certain gap between the inner and outer rings of the rolling bearing and the rolling elements, so there can be relative displacement between the inner and outer rings. When there is no load, one ring is fixed and the other ring moves from one extreme position to another extreme position along the radial and axial directions of the bearing, which are called radial clearance and axial clearance, respectively.

According to the state of the bearing, the clearance is divided into three types.

1. Original clearance. It refers to the clearance of the rolling bearing in the free state before installation, which is determined by the processing and assembly of the bearing manufacturer.

2. Installation clearance, also called fit clearance. It is the clearance when the bearing and the shaft and the bearing seat are installed but not yet working. Due to interference installation, or the inner ring is enlarged, or the outer ring is reduced, or both, the installation clearance is smaller than the original clearance.

3. Working clearance. The clearance of the rolling bearing in the working state: the inner ring has the largest temperature rise and thermal expansion during operation, which reduces the bearing clearance. At the same time, due to the load, the contact between the rolling elements and the raceway produces elastic deformation, which increases the bearing clearance. Whether the working clearance of the bearing is larger or smaller than the installation clearance depends on the combined effect of these two factors.