The present invention relates to a hydrostatic piston machine.
Hydrostatic piston machines having a rotor, a plurality of pistons rotatable with the rotor, and a displacing element operative for effecting reciprocation of the pistons, have been widely known. The displacing element has a surface which is in sliding contact with the pistons, and more particularly with sliding shoes of the piston. In the known hydrostatic piston machines, a portion of the above-mentioned surface of the displacing element, which is in sliding contact with the sliding shoes of the pistons has been formed as a smooth surface. It has been shown that during rotation of the pistons relative to the displacement member when the sliding shoes of the pistons are in sliding contact with the surface of the displacing member, increasing friction losses take place as a result of viscous friction therebetween. These friction losses result in loss in efficiency of the hydrostatic piston machine. This is particularly characteristic when the machine operates with a great number of revolutions.