PISTON TYPE LIQUID PRESSURE DEVICE

PROBLEM TO BE SOLVED: To improve wearing resistance and seizure resistance when a device is operated at a high pressure, by positioning a load force point in a radial direction, acting in a cylinder block, in the vicinity of the center in an axial direction of a spline part. SOLUTION: An internal diametric spline part 2d in a neck part internal peripheral surface of a cylinder block 2 is fitted to an external diametric spline part 3a of a shaft 3, and a spherical washer 10 of spherical external shape is slidably mounted in a cylindrical neck part peripheral surface to be energized leftward. In this way, a piston shoe 7 is brought into press contact with a swash plate 5 through a shoe plate 6. A point of application of load force P in a radial direction acting in the cylinder block 2 from a piston 4 is positioned in the vicinity of the center in an axial direction of the internal diametric spline part 2d. An escape 16, gradually enlarged in both sides in the axial direction with a corresponding point Q on the periphery serving as the vertex, is provided so as to prevent the cylinder block 2 from tilting even when the shaft 3 is deflected by a load.