The metal skeleton is like the steel bars in the concrete member, which acts as a reinforcement and enables the oil seal to maintain its shape and tension. 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". 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.
The outer edge of the oil seal fixes the oil seal in the cavity hole, and at the same time plays the role of preventing fluid leakage and intrusion from the contact surface between the outer peripheral surface of the oil seal and the inner surface of the cavity. In addition, the metal frame is to maintain the matching force when the oil seal is fixed in the cavity.
The sealing lip is a flexible elastomer designed to maintain a stable sealing effect under the influence of mechanical vibration and pressure fluctuations of the sealing fluid, and to maintain a stable contact state between the lip and the shaft surface. The spring can increase the pressing force of the sealing lip to the shaft and maintain this pressing force. The lip end is made into a wedge shape, pressing the shaft surface at the end to seal the fluid.
The dust lip is an auxiliary lip that is not connected to the spring, and plays the role of preventing the intrusion of dust.