| 摘要 |
PURPOSE:To make it possible to stably vary the displacement of a hydraulic rotary machine of radial piston type, by increasing the pressing force by a control piston mechanism in both directions of increase and decrease in the displacement so that a cam ring is pressed and held by the control piston mechanism. CONSTITUTION:Restitutive force acting upon a cam ring 11 takes a maximum value Fxmax in the direction of increase in the displacement of a hydraulic rotary machine, and also takes a maximum value ¦Fxmin¦ in the direction of decrease in the displacement. Meanwhile, a force muFy acts on the cam ring 11 when the latter horizontally moves. Therefore, if a pressing force FA by a control piston 23 is made larger than the force, Fxmax+muFy, and a pressing force FB by a control piston 24 is made larger than the force, ¦Fxmin¦+muFy, when a control valve 27 is switched over after a hydraulic pump 16 is communicated with a cylinder chamber 21, the cam ring 11 is surely abutted against the inner peripheral wall of a casing 1, thereby the displacement of a hydraulic rotary machine may be stably changed. |
