目前，国内生产制造的机械产品同国外先进机械产品相比，尚存在着差距，这些差距主要反映在基础部件上，如液压元件，体积大性能低、渗漏油现象严重。而国外引进的机械产品的液压系统质量较稳定，经长期使用渗漏油较小。因不重视机械产品清洁度而造成质量低、产品出动率差、寿 At present, there are still some gaps in mechanical products manufactured in China as compared with foreign advanced mechanical products. These gaps are mainly reflected in the basic components such as hydraulic components, large volume and low performance, and serious leakage of oil. The quality of imported hydraulic system of mechanical products is more stable, the leakage of oil through the long-term use of smaller. Due to the lack of attention to cleanliness of mechanical products caused by low quality, poor product mobility, life