In moving parts, parts wear due to long-term friction. When the gap between the shaft and the hole wears to a certain degree, the parts must be replaced. Therefore, the designer chooses the lower hardness and better wear resistance when designing. The material is a bushing or bushing, which can reduce the wear of the shaft and the seat. When the bushing or bushing is worn to a certain degree, it can be replaced. This can save the cost of replacing the shaft or the seat. Generally speaking, the bushing and the seat are used. Interference fit, and clearance fit with the shaft, because in any case, wear can not be avoided, it can only extend the life, and shaft parts are relatively easy to process; some new designers do not like this design, think this The cost is increased during manufacturing, but after a period of use, it is still necessary to rebuild according to this method, but the remodeling is easy to reduce the accuracy of the equipment, the reason is very simple, the secondary processing cannot guarantee the position of the center of the seat hole .

The shaft sleeve is used in place of rolling bearings (such as camshafts) in places where the speed is low, the radial load is high and the clearance requirements are high (such as camshafts). The material requires low hardness and wear resistance. The shaft The inner hole of the sleeve is ground and scraped to achieve higher matching accuracy. There must be an oil groove on the inner wall. Lubrication of the sleeve is very important. If dry grinding, the shaft and the sleeve will be scrapped soon. It is recommended to scrape during installation The inner wall of the sleeve, so that many small pits can be left to enhance lubrication.