Swashplate assembly for a swashplate type hydraulic pressure device

A swashplate type hydraulic pressure device comprising:

• a cylinder having an axis;
• a number of plungers axially slidably disposed in a number of cylinder bores which are arranged in said cylinder annularly around the axis thereof;
• a swashplate holder disposed opposedly to the tip ends of said plungers;
• and
• a swashplate rotatably supported on said swashplate holder and having a number of spherical concave portions formed on a surface thereof to be abutted by spherical ends which are formed at the tip ends of the plungers;
• wherein said spherical concave portions are each formed to have a radius of curvature larger than that of the associated spherical end of the plunger and a center point of engagement between the spherical concave portion and the associated spherical end of the plunger is displaceable in an inclined state of the swashplate, in response to sliding motion of the plunger in said cylinder bore, between a radially outer side position at which said center point of engagement is located radially outer than an axis of the plunger with respect to the cylinder axis and a radially inner side position at which said center point is located radially inner than said axis of the plunger with respect to the cylinder axis;
• and
• wherein radial forces acting on said swashplate at respective center points of engagement between the spherical concave portions and the spherical ends of the plungers are directed such that the radial forces appearing in the spherical concave portions located on a substantially same diametrical line on the swashplate work to offset each other regardless of the angle of inclination of the swashplate so as to center said swashplate.