从漏油的部位分析，绝大多数是从低压腔往外漏，也就是从压力腔大量渗油到低压腔(内漏)的油，由于系统中有一定的背压，使低压油的一部分外漏;也有的液压元件低压腔根本不允许回油，如单臂液压机液压泵的轴伸部位。各类液压泵从传动轴伸处向外漏油的情况较普遍，尤其是齿轮泵的轴颈端盖里的自紧旋转橡胶密封圈。此类结构的自身漏油原因有：
(1) The axial clearance of the pump exceeds the specified value, a large amount of pressure oil enters the low pressure area, and the self-tightening rotating rubber sealing ring is flushed to leak oil;
(2)单柱液压机泵在系统中常年使用磨损，使轴向间隙增大，而压力油大量进入低压区，将旋转密封圈冲开向外漏油。
(3) For newly processed and assembled hydraulic pumps, the geometric dimensional tolerance of a component in the manufacturing process exceeds the specified value, or the cumulative dimensional tolerance of several components exceeds the specified value.
GEO-CANARY-86EA1707