| 摘要 |
PURPOSE:To make it possible to reduce the passage resistance to a negligible quantity when hydraulic oil is sucked and previously prevent troubles caused by cavitation, by forming a supply passage of the hydraulic oil in a piston pump. CONSTITUTION:When a pressure reducing process goes forward, the hydraulic oil 6 within a housing 17 is rapidly sucked from a suction port 20 by a pressure difference between the housing 17 and the second chamber 5. This is caused by the fact that the passage resistance is negligible when the hydraulic oil 6 within the housing 17 flows into the second chamber 5 since a supply passage 19 has been formed within a piston pump 18 so that the hydraulic oil only passes through the thickness of the wall of the piston pump 18. The hydraulic oil 6 increased by a suction quantity obtained by the reduction of this passage resistance can be assured, so that the conventional occurrence of troubles, due to cavitation can be previously prevented. |
