| 摘要 |
PURPOSE:To easily cut the surge pressure by installing a selector valve for the communication between the pressurizing chamber of a variable element for varying the discharge flow rate of a pump to a discharge line and selecting the selector valve by a large differential pressure between before before and behind a throttle when a surge pressure is generated in the discharge line. CONSTITUTION:As for a high response control pump 10 in which the discharge flow rate of a pump part 15 is varied by controlling the displacement of a variable element 11 consisting of swash plate, etc. against a spring 12, the pressurizing chamber 11a of the variable element 11 is allowed to communicate to a tank 18 through a flow passage 31 formed on a proportional electromagnetic control valve 19 controlled according to the difference for each set value of flow rate and pressure or to a pump discharge line 16 through a flow passage 34. Further, the pressurizing chamber 11a is allowed to communicate to the pump discharge line 16 through a flow passage 32 formed on a selector valve 23. The selector valve 23 is selection-controlled so as to communicate to the flow passage 32 when a surge pressure is generated in the pump discharge line 16 and a large pressure difference is generated between before and behind a throttle 29 in the flow passage 34. |
