To provide a piston type liquid apparatus capable of suppressing a change in the contact position of a cam with a piston.
An oil pump 6 has a cam 22 provided on a first member 18, pistons 35 and 36 mounted on a second member 25, and a liquid chamber 39 formed in the second member 25, wherein the contour of the cam 22 is configured to produce a first load F2 to press the second member 25 in the direction along the rotational axis X1 when the pistons 35 and 36 are pressed to the cam 22. The oil pump 6 is provided with a first adjustment chamber 130 to admit inflow and outflow of the liquid and a pressure receiving surface 126 which gives the second member 25 a second load F3 directed oppositely to the first load F2 with the pressure of the first adjustment chamber 130, wherein the area of the pressure receiving chamber 126 is arranged to align the first load F2 with the second load F3, and passages 48, 137, 144 for supplying the liquid in the liquid pressure chamber 39 to the first adjustment chamber 130.
FUJIYOSHI NAOSHI
SHIOIRI HIROYUKI
