Abstract: A suction-restricted radial piston pump is described, in particular for use with automotive vehicles. The pump delivers a flow constant over a broad speed range and involving low losses in output and generating only negligible noise. In one embodiment, a control slot (13), on the pressure side, is subdivided into several grooves (27,28) which at least in part are in communication, through check valves (32), with the pressure connection (20). An alternative embodiment provides a shape of the pressure-sided control slot in which the introducing end thereof is comparatively narrow to reduce noise at a high speed and the outlet-sided end thereof with a wider width sufficient to meet the required output. According to a third embodiment, the suction-sided slot (12) is provided with a narrow width section and a subsequent wider width section.

Abstract: A vane-type motor is disclosed including a rotor disposed in a housing having a plurality of cam rings surrounding the rotor, which cam rings are displaceable relative to one another in the circumferential direction. Vanes associated with the cam rings subdivide a work chamber provided between the rotor and the cam rings into work cells and side plates laterally confine the work chamber. An inlet channel supplies pressure fluid to the work chamber and a discharge channel provides for discharge of the pressure fluid from the work chamber. Control channels are provided to preclude pressure impacts and noises with the cam ring displaced. The control channels terminate in the work chamber and connect the work chamber to the inlet channel. The rotor forms a control element for the control channels.