| 摘要 |
PROBLEM TO BE SOLVED: To reduce energy consumption and more stably control the discharge amount of a pump in a structure capable of using many components in common with a pump unit having no load sensing function, in a pump system.SOLUTION: A pump system includes a hydraulic pump, and balance piston mechanisms 94, 98 connected to an operation part of a movable swash plate 90 and having a piston body 112 provided axially slidable in 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. Into the first pressure receiving chamber 196 and the second pressure receiving chamber 200, operating fluid pressure on the primary side of an actuator selector valve and that on the secondary side thereof are introduced, respectively. Into the third pressure receiving chamber 202, preset set pressure is introduced which is equivalent to operating fluid differential pressure generated between before and after passage, in a steady state at an operation position of the actuator selector value. |
