Abstract: A flow regulator valve that is intended particularly for positive-displacement pumps for auxiliary power steering systems in motor vehicles contains in a valve borehole (1) a flow regulator piston (3) that is guided in an axially movable and sealing manner. Inside flow regulator piston (3), there is arranged a pressure limiting valve (18) whose closing body (19) is pressed against a valve seat (22) by the force of a spring (21). The force of spring (21) is adjusted by a headless pin (23) which--in its adjusted position--is secured with respect to flow regulator piston (3) by a locknut (25).

Abstract: A regulatable vane pump is provided with a piston operable by differential pressure responsive to booster steering flow demand wherein the piston movement controls a choke bore flow area. The differential pressure is effected by pump pressure on one face of the piston and consumer pressure on the opposite face of the piston, e.g., pressure in a booster steering servomotor. The choke bore has an aperture covered or uncovered by a choke plate carried by a pin on the piston. The choke plate is normally in position so as not to impede flow through the choke and the piston is in a position such that pump outlet flow is blocked from a bypass passage back to the pump inlet. However, with rise in vehicle speed under non-steering conditions, causing pressure on the one face of the piston to shift it along with the choke plate, the choke bore is closed, or partially so, and the unnecessary output pressure flow shunted back to pump inlet.

Abstract: A regulatable vane pump is provided with regulating apparatus incorporated in the pump having a differential pressure piston operable responsive to booster steering flow demand wherein the piston carries a flexible leaf spring having a flat surface which serves as a shut off member against ports in a restrictor member. Actuation of the regulating piston carries the leaf spring toward the ported member to progressively shut off restrictor ports in the face of the ported member, either partially or fully depending upon the ported arrangement. As ports are gradually closed off regulation of the pump discharge is effected at various demand pressures after linear rise of rate of discharge up to a regulating point. Thereafter, there is wide separation of characteristics of regulating curves or lines for differing pressure demands. The overall effect produces a precise regulation within narrow limits as well as an economy of manufacture.