| 摘要 |
<p>A two-stage solenoid-operated hydraulic piston pump has serially arranged pump chambers 50, 88 each having an input passage 52, 80 and a delivery passage 66, 90. The first stage has a larger displacement volume than the second stage such that complete filling of the second stage is attained. The piston 38 of the first stage is reciprocated through the co-operation of a spring 56 and a selectively energizable solenoid coil 16,18. The piston 62 of the second stage is secured to and reciprocable with the first-stage piston. The cylinder 64 for the second stage has an overflow passage 84 disposed to ensure that all the fluid discharged from the first stage prior to the second-stage piston closing the overflow passage passes through the second-stage cylinder.</p> |
