The oil seal structure consists of three parts: the oil seal body, the reinforced skeleton and the self-tightening coil spring. The sealing body is divided into bottom, waist, cutting edge and sealing lip according to different parts. Generally, the inner diameter of the skeleton oil seal in the free state is smaller than the shaft diameter, that is, it has a certain “interference amount”.
Therefore, after the oil seal is installed on the oil seal seat and the shaft, the pressure of the oil seal edge and the contraction force of the self-tightening coil spring will generate a certain radial tightening force on the shaft. After a period of operation, the pressure will rapidly decrease or even disappear. , Therefore, adding a spring can compensate the self-tightening force of the oil seal at any time.