The role of various parts of the oil seal
The oil seal is mainly composed of a sealing body, a reinforcing skeleton, and a self-tightening coil spring. According to different parts, the seal body is divided into a bottom, a waist, a cutting edge and a sealing lip. The following figure shows the main names and terms of the parts of the inner-shell skeleton seal with spring and dust lip attached. Oil seal use site
The metal skeleton acts like a reinforcing bar inside the concrete structure, which reinforces it and allows the oil seal to maintain its shape and tension. Generally, in the free state, the inner diameter of the skeleton oil seal is smaller than the shaft diameter, that is, it has a certain “interference amount”. Therefore, when the oil is encapsulated into the oil seal seat and the shaft, the pressure of the oil seal edge and the contraction force of the self-tightening coil spring generate a certain radial tight force on the shaft. After a period of operation, the pressure will rapidly decrease and even disappear. Therefore, plus the spring can always compensate for the oil seal self-tightening force,
The outer edge of the oil seal seals the oil seal in the bore of the cavity and simultaneously prevents the fluid from leaking and invading from the contact surface between the outer circumferential surface of the oil seal and the inner surface of the cavity. In addition, the metal skeleton serves to maintain the combining 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 vibrations 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 the pressing force. The lip end is made in a slant shape, pressing the shaft surface at the end, acting as a sealing fluid.
The dust lip is an auxiliary lip that is not connected to the spring and prevents dust from intruding.