The temperature of the bearing can generally be inferred from the outdoor temperature of the bearing. If the oil hole is used, the temperature of the outer ring of the bearing can be directly measured. The temperature of the bearing starts to rise slowly with the operation of the bearing, and reaches a stable state after 1 to 2 hours. The normal temperature of the bearing varies with the heat capacity, heat dissipation, speed and load of the machine. If the lubricating installation is not suitable, the bearing temperature will rise sharply, resulting in abnormally high temperature. At this time, it is necessary to stop and take necessary preventive measures.