What is bearing preload? 

Generally, rolling bearings have a certain clearance under working conditions. However, in order to achieve a specific purpose, when configuring the bearing, the bearing can obtain a certain internal load through a certain adjustment method and use it in a negative clearance state. This method of use is called preload.

What are the benefits of preload on bearings? For rolling bearings, proper preload can have the following benefits:

1. Improve the rotation accuracy. After the bearing is preloaded, the internal clearance is eliminated, and each rolling element bears a certain preload, supporting the ferrule from all directions, which can improve the rotation accuracy, enable the shaft to be positioned correctly in the axial and radial directions, and improve the shaft. Rotational accuracy, such as machine tool spindle bearings and measuring instruments.

2. Improve rigidity. The contact between the rolling element and the raceway is elastic contact, and the rolling element can be regarded as a spring. Bearings with clearance are only supported by a few springs in the direction of force. The preloaded bearing is supported by springs in all directions, and has a certain amount of preload, and the number of rollings under the load is more than that of the bearing, so the rigidity can be improved. In ball bearings, the relationship between the contact deformation of the ball and the raceway and the load is nonlinear, and the contact stiffness increases with the increase of the preload.

3. Improve bearing life. After preloading, the number of loaded rolling elements increases, the load on each rolling element decreases, and the load can be distributed evenly on each rolling element, so the life of the bearing can be improved.

4. Improve bearing damping and reduce noise. Preloading establishes a stable oil film between the rolling elements and the raceways, improves the damping between the rolling elements and the raceways, improves the dynamic characteristics of the support structure and reduces noise.

5. Improve the dynamic performance of angular contact ball bearings. In high-speed rotating angular contact ball bearings, proper preload can prevent the gyroscopic rotation of the steel ball, prevent or reduce the revolving slip of the steel ball, and control the spin sliding of the steel ball.

6. Inhibit vibration lines and friction and wear. The outer spherical bearing is actually a variant of the deep groove ball bearing. The outer spherical bearing is mainly used to bear the combined radial and axial load mainly based on the radial load, and it is generally not suitable to bear the axial load alone. It is used for vibration-free machining of low-roughness machining machines, or in mechanisms that need to control friction and wear when starting and stopping frequently.

7. Control the slip phenomenon of rolling body revolution and rotation. Spherical bearing with seat This type of bearing is also designed to be self-aligning, easy to install, and has a double-structured sealing device, which can work in harsh environments. The bearing seat is generally cast.

Bearings with housings are high-precision components made up of grease-sealed deep groove ball bearings and housings of various shapes. The bearing assembly can be directly installed on the main body of the mechanical device through several bolts, has the self-aligning function, can supplement the grease, etc. It is a product that is very easy to install and use.

8. Compensate for wear during operation. Bearings will increase in clearance due to wear during operation, which can be compensated by preloading