| 摘要 |
PROBLEM TO BE SOLVED: To provide a flow rate control device of a variable displacement hydraulic pump capable of making horsepower control and cut-off control compatible.SOLUTION: A flow rate control device 1 of a variable displacement hydraulic pump includes: a servo mechanism 2, a switch mechanism 3, a horsepower control mechanism 4, and a cut-off mechanism 5. The cut-off mechanism 5 includes a cut-off piston 51, a first cut-off pressure-receiving chamber 52 applying discharge pressure of a hydraulic pump 11 on the cut-off piston 51 so as to make the cut-off piston 51 move a spool 31 of the switch mechanism 3 in a flow rate reducing direction, and a second cut-off pressure-receiving chamber 53 which applies cut-off pressure resisting the discharge pressure of the hydraulic pump 11 on the cut-off piston 51. Into the second cut-off pressure-receiving chamber 53, the cut-off pressure is outputted from an electromagnetic proportional valve 8A. A selecting mechanism 6 decides which of the horsepower control piston 41 and the cut-off piston operates the spool 31.SELECTED DRAWING: Figure 1 |
