CAM PLATE PISTON TYPE HYDRAULIC DEVICE

PURPOSE:To improve wear resistance so as to lengthen a service life by leading a high pressure fluid to each sliding part. CONSTITUTION:In a piston pump controlling the inclined rotation angle of a yoke 8, holding a cam plate, by the moment balance of a control piston 10 and a bias piston 12, pressure liquid led to the bias piston 12 is led to the sliding face between the bias piston 12 and a first shoe 7A through a first liquid passage 12a, and the pressure liquid led by the first liquid passage 12a is led to the sliding face between the control piston 10 and a second shoe 7B through a second liquid passage 8b and also led to the sliding face between the oscillating shaft 8a of the yoke 8 and its bearing 9 through a third liquid passage 8c so as to lubricate each sliding face. At the same time, repulsive force is generated to each sliding part to reduce load.