A motor cannot work without bearings. "Because the shaft can move in any direction, the motor requires that the shaft only rotate when it is operating.". Theoretically, it is impossible to achieve the transmission effect. Moreover, bearings can also affect the transmission. In order to reduce this impact, good lubrication must be achieved on the bearings of high-speed shafts. Some bearings already have lubrication, called pre lubricated bearings, while most bearings must have lubricating oil. During high-speed operation, friction not only increases energy consumption, but also makes it easy to damage the bearings. The idea of converting sliding friction into rolling friction is one-sided, because there is something called sliding bearings.