How to Choose Bearing Matching?

Whether the choice of bearing coordination is correct or not not only affects the normal operation of machinery and equipment, but also affects the performance of the bearing itself. Therefore, it is very important to choose the right cooperation. Generally speaking, the cooperation should be selected according to the type, size, working temperature, rotation accuracy of bearing load and other factors.

1. Types of loads

According to the rotation of the synthetic radial load vector acting on the bearing relative to the sleeve, it is divided into fixed load, rotary load and swing load. Fixed load refers to the synthetic radial load acting on the ring, which is borne by the local area of the ring raceway. The synthetic radial load vector is relatively static with the ring. In this case, gap matching is generally selected. Rotary load refers to the rotation of the synthetic radial load vector acting on the ring along the circumference direction, which is carried by various parts of the raceway in turn. In this case, over-earning cooperation is generally selected, if gap cooperation is adopted. Relative sliding in the circular direction will occur on the matching surface, resulting in friction, wear and heating on the matching surface, and eventually causing abnormal damage to the bearing. However, in some special cases, such as the rotating load is very light, or the bearing needs to be installed and disassembled frequently, a looser combination can also be selected. Swing load refers to the relative swing of the synthetic radial load vector acting on the ring in a certain area of the ring raceway, or the load acting on the bearing is an impact load or vibration load, and its direction or value often changes. In this case, over-earning or transition cooperation is generally selected.

2. The size of the load

Under the action of radial load, due to the compression deformation of the two objects on the joint surface, the excess surplus of the joint is reduced. Therefore, the load size also has a great impact on the coordination. According to the ratio of the radial equivalent dynamic load acting on the bearing to the rated dynamic load, the load size can be divided into three types: light load, normal load, heavy load, etc. In order to prevent over-earning changes from slipping, heavy loads should usually be tighter than those under light loads and normal loads.

3. Operating temperature

When a bearing is running, the temperature of the bearing sleeve is usually higher than that of adjacent parts. The inner ring may loosen the coordination with the shaft due to thermal expansion, while the outer ring may affect the axial swimming due to thermal expansion. When choosing cooperation, the difference in temperature and the direction of heat conduction must be considered.

4. Rotation accuracy of bearings

When the rotation accuracy and operation stability of bearings are required to be high, in order to eliminate the impact of elastic deformation and vibration, gap matching should be avoided as much as possible.

The above are the basic principles and basis for bearing matching selection. For general working conditions. According to the cooperation recommended by the national standard GB/T275-1993 "Cooperation of Rolling Bearings with Shafts and Shells" can meet the use requirements. However, for some special applications, after comprehensive consideration, analysis and calculation of load, temperature rise and rotation accuracy, suitable cooperation should be selected. Secondly, factors such as bearing speed, bearing housing material, installation and disassembly, and axial displacement also have a certain impact on bearing coordination. When choosing cooperation, they should This should be considered comprehensively according to actual usage and requirements.

The author of this article is Shaanxi Gainhui Heavy Industries Co., Ltd., which is a professional bearing manufacturer and distributor in China. The company supplies many types of the bearings, such as spherical roller thrust bearings, barrel roller bearings, etc. With high quality and competitive bearing products, we sincerely provide services to customers all over the world.

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E-mail: emily@gainhui.com

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