旋转油封环的密封和使用寿命,曾是彭浦机器厂和天津工程机械研究所在试制与试验240马力推土机液力变矩器和变速箱时有待解决的一个问题。我们曾选用过合金铸铁和聚四氟乙烯,经实际试车,均不理想。合金铸铁易磨损,使用20～30小时后磨损量达0.6毫米,寿命短。聚四氟乙烯,耐腐蚀耐磨损性能较好,但在高温下(80℃以上)易软化,失去弹性,破坏密封作用,因而造成变矩器及变速箱漏油。后来上海材料所推荐我们试用聚酰亚胺 The sealing and service life of the rotating oil seal ring were once a problem to be solved when Pengpu Machinery Factory and Tianjin Institute of Construction Machinery tried and tested the 240-horsepower bulldozer hydraulic torque converter and gearbox. We have used alloy cast iron and Teflon, which are not ideal after actual test. The alloy cast iron is easy to wear, and the wear amount reaches 0.6 mm after 20 to 30 hours, and the service life is short. PTFE has good corrosion and wear resistance, but it easily softens at high temperatures (above 80°C), loses its elasticity and destroys the sealing effect, thus causing oil leakage in the torque converter and gearbox. Later Shanghai Materials Institute recommended that we try polyimide