| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure capable of making many components be in common for a pump unit not having a load sensing function, to reduce energy consumption, and to more stably control a discharge amount of a pump, in a swash plate angle control system.SOLUTION: A swash plate angle control system includes a hydraulic pump, and balance piston mechanisms 94, 98 connected to an operation part of a movable swash plate 90 and provided with a piston body 112 provided slidably in an axial direction inside a cylinder 182. The balance piston mechanisms 94, 98 have first, second and third pressure receiving chambers 196, 200, 202 provided in the cylinder 182. Working fluid pressures on the primary side and secondary side of an actuator switching valve are respectively introduced to the first pressure receiving chamber 196 and the second pressure receiving chamber 200, and a set pressure which is set beforehand and is equivalent to a working fluid differential pressure generated before and after passing in a stationary state at an action position of the actuator switching valve is introduced to the third pressure receiving chamber 202. |
