1. Inadequate seal kits are the main cause of oil leakage. When the shaft wears and forms a groove, and the seal kit cannot be seal even if the seal kit is replaced with a new one, it is because the contact pressure between the seal kit lip and the shaft decreases, resulting in too little interference between the seal kit lip diameter and the shaft diameter after installation. Taking the crankshaft seal kit of the S195 diesel engine as an example, the main reasons for its poor seal kit are:
① Poor quality of seal kit manufacturing;
② Poor shaft or bearing quality;
③ Improper use and maintenance;
④ Improper installation;
⑤Improper storage and adverse effects caused by environmental pollution.
2. Treatment of seal kit lip damage
(1) Lip damage:
- The seal kit will cause high temperature carbonization and wear failure of rubber after long-term use. Abrasive wear of the seal caused by continuous high-speed, high-temperature sliding contact between the shaft and the seal kit for a long time. The peripheral speed of the shaft is also a key factor affecting the sealing effect. The greater the contact pressure between the lip of the seal kit and the shaft surface, the higher the relative movement speed, the faster the temperature rise caused by friction, and the higher the temperature, making the lip Wear, burns, and cracks cause the seal of the seal kit to fail and shorten the service life of the seal kit.
(2) Wear of the shaft:
- Due to the long-term use of the reducer, the wear of the shaft seal is extremely poor. In some serious cases, even V-shaped grooves appear. Once this groove is formed, the interference between the seal kit lip diameter and the shaft diameter becomes smaller, resulting in seal kit lips. The contact pressure with the shaft decreases, and the oil film can easily leak out of the groove marks, eliminating the sealing effect of the seal kit. At the same time, the surface roughness of the shaft has a great impact on the performance and service life of the seal kit. The roughness is too low, and the oil is easily squeezed out of the sealing contact surface, so that the oil film becomes thin, causing the lips to heat up. The roughness is too high, the shaft is easy to scratch the lips after high-speed rotation, making the sealing surface fluff, the friction torque increases, and the lips wear quickly and cause leakage.