某些液压控制的机械,如机床、压榨机、金属成形及塑料等机械,工作时具有短期大负载(工作压力可达1500～2000巴),小流量的特点。为提高其工作压力,可采取增大活塞面积或使用高压泵的方法。但都有一定的局限性。因为加大活塞面积,在一定流量条件下,活塞移动速度慢。当然,工作速度慢些是必要的,但趋近工件时的速度太慢,则必影响机械的生 Some of the hydraulic control of machinery, such as machine tools, presses, metal forming and plastics and other machinery, work with short-term high load (working pressure up to 1500 ~ 2000 bar), the characteristics of small flow. To increase their work pressure, take the approach of increasing the piston area or using high-pressure pump. But all have some limitations. Because of increased piston area, under certain flow conditions, the piston moves slowly. Of course, slower work is necessary, but when approaching the workpiece, the speed is too slow, it will affect the mechanical life