What is the cause of the motor shaft problem causing the bearing to overheat?
First, the shaft problem of the motor is the most common motor, the deep groove ball bearing, and the cylindrical roller bearing. When installed, one end is axially positioned, and the other end is axially floated. First of all, I think you should check the incitement you said. How is your axial positioning done? Is the positioning reliable? If reliable, for deep groove ball bearings, its axial yaw should be its axial clearance. Generally not too big, but it depends on the radial clearance you choose. It cannot be used as a locating bearing for the N and NU series for cylindrical rod bearings. If you use them for positioning, they must be too large.
Second: You said that the shaft is moving. If the positioning bearing is subjected to excessive axial load, it will cause the bearing to burn. Therefore, when choosing a locating bearing, look at how much the axial load is whether the bearing you choose can withstand it. In the NJ series of cylindrical rod bearings, this axial load is entirely absorbed by the sliding part, so it is not acceptable. For deep groove ball bearings, its axial capacity is up to a quarter of the radial, which varies from bearing to bearing.