What is the difference between axial clearance and radial clearance?

Axial clearance and radial clearance are two important concepts in the field of bearings. The main differences between them are reflected in the following aspects:


1. Definition and direction:

Axial clearance: refers to the gap along the axial direction caused by the relative movement of the inner and outer rings when the bearing is under load. The size of this gap has an important influence on the operating performance of the bearing, such as rotation accuracy and stability.

Radial clearance: refers to the movement of the other ring from one extreme position to another extreme position relative to the fixed ring along the radial direction (i.e., diameter direction) when there is no load.


2. Measurement and influence:

The measurement of axial clearance is usually carried out using a micrometer or thickness gauge, while the measurement of radial clearance varies depending on the bearing type and specific measurement method.

The size of the clearance (working clearance) during operation affects the rolling fatigue life, temperature rise, noise, vibration and other performance of the bearing. When measuring the bearing clearance, in order to obtain a stable measurement value, a specified measurement load is generally applied to the bearing.

3. Adjustment and influence:

The adjustment of axial clearance and radial clearance is to ensure that the bearing can run smoothly and efficiently.

When the bearing clearance is too small, the bearing is most likely to heat up, and may even cause the bearing to lock, causing damage to the bearing shaft or housing bearing seat.

When the bearing clearance is too large, it will cause the rotor to move during operation, affecting the rotation accuracy and stability of the bearing.


4. Application scenarios:

Different types of bearings and different application scenarios may require different clearance settings. For example, when spherical bearings (spherical sliding bearings) swing, tilt and rotate under low speed and heavy load, they must have a certain clearance to ensure their normal movement.


There are significant differences in the definition, measurement, adjustment and influence of axial clearance and radial clearance. These differences require engineers and technicians to carefully consider the selection and adjustment of clearance when designing and maintaining bearing systems to ensure the performance and reliability of bearing systems.