目前在机械化支架的液压支柱和千斤顶中都采用服务期限为1～2年的单项动作式橡胶密封圈。尽管这类密封圈有缺点,但在压力为63兆帕以下的情况下用于液压支柱和千斤顶可以认为是令人满意的。 近年来,在国外的液压缸中广泛采用双向动作式密封件。这种密封件与单向动作式密封件的区别在于尺寸小以及工作表面的摩擦和磨损量小。此外,这种密封件能缩短活塞的轴向尺寸,减少安装沟槽的数目并能减轻密封结点的拆装工作。国外各有关公司都 Currently in the mechanized stent hydraulic props and jacks are used for a period of one to two years of service-type rubber seals. Despite the disadvantages of this type of seal ring, the use of hydraulic struts and jacks at pressures below 63 MPa is considered satisfactory. In recent years, widely used in foreign hydraulic cylinder bi-directional action seal. The difference between this type of seal and the one-way acting type seal is the small size and the small amount of friction and wear on the work surface. In addition, this seal can shorten the axial piston size, reducing the number of mounting grooves and can reduce the sealing node disassembly work. All foreign companies are