On a lathe, the main shaft is generally assembled with a rolling bearing or a sliding bearing, and rotates at a high speed, thereby generating a large amount of heat.

  The main shaft bearing is the main heat source in the headstock. If the heat produced by it is not discharged in time, it will cause the bearing to overheat and increase the temperature of the corresponding part of the lathe, resulting in thermal deformation. In severe cases, the main shaft and the tailstock will be unequal in height. This not only affects the accuracy and machining accuracy of the lathe itself, but also burns out the bearings and even the spindle.

  The reasons for the overheating of the spindle can be summarized as follows: too small spindle bearing clearance increases frictional force and frictional heat; in long-term full-load turning, the rigidity of the spindle is reduced, bending occurs, and the transmission is unstable and generates heat. When troubleshooting this fault, attention should be paid to: adjust the spindle bearing clearance to make it appropriate; control the supply of lubricating oil and clear the oil circuit; try to avoid long-term load on the lathe.

  Based on years of practical experience, it is concluded that the main measures to reduce the heat generation of bearings are:

  (1) Appropriately reduce the diameter of the rolling elements. Reducing the diameter of the rolling elements can reduce centrifugal force and gyroscopic moment, thereby reducing friction and heat generation.

  (2) Using new materials. For example, ceramic materials are used as rolling elements. Compared with steel ball angular contact ball bearings, ceramic ball bearings reduce the rolling and sliding friction between the balls and the raceway during high-speed rotation, and reduce the heat generation.

  (3) Use a reasonable lubrication method. Lubrication methods such as oil and gas and oil mist not only have a lubricating effect on the bearing, but also have a certain cooling effect.