It is found that the PTFE oil seal has the characteristics of high oil resistance, high corrosion resistance, high temperature resistance, small friction coefficient and long service life. At the same time, the PTFE oil seal has been continuously developed, and domestic products are becoming more and more mature, and now it has been widely used. .

According to the working environment and the speed of the diesel engine, in order to better improve the oil seal performance and reduce the market failure rate, it is now prepared to replace the materials of the front and rear oil seals with polytetrafluoroethylene (PTFE). The PTFE oil seal has distinctive features, but because of the certain difference between the structure of the PTFE oil seal and the rubber oil seal, its lip material does not have the same high elasticity as the rubber, the quality of the parts is unqualified, and the installation process is improper, etc. Will cause the PTFE lip to flip, scratch, etc., resulting in oil seal leakage. In response to this special nature, the diesel engine parts and assembly process are fully rectified.

Firstly, the parts are improved, the roughness of the shaft is too large, the material of the lip is easy to be cut to make the oil seal wear early, and because the rough peak is too large, the thickness of the oil film is too thick and it is easy to leak; the roughness of the shaft is too small, and the radial force acts. Next, it is easy to extrude the oil film from the concave portion of the rough peak, and the thickness of the oil film is thinned to form dry friction. Considering comprehensively, the surface roughness of the crankshaft belt is now increased to Ra0.8.

During the assembly process, avoid direct contact with the oil seal lip, causing contamination of the sealing lip, or moving the PTFE lip to cause irregular deformation; using appropriate tooling to prevent the PTFE main lip from rolling, adjusting the press-fit stroke and pressure of the device The loading speed and the angular position are press-fitted, and then the coaxiality and the perpendicularity of the installation tool and the oil seal mounting cavity are adjusted; when the oil seal is pressed into the cavity, it is preferable to limit the pressing depth of the oil seal by the press-fit tool; the oil seal pressure After being installed, it should be kept for 2~5s to prevent the oil seal from rebounding. Dongguan PTFE U-type oil seal manufacturers through diesel engine endurance test, pilot tracking verification and market failure statistics, diesel engine crankshaft oil seal oil leakage phenomenon has been significantly improved, can gradually promote PTFE oil seal.