Dual-stage pump with switching valve

Abstract

The present invention relates to a dual-stage pump for a hydraulic system with a housing, a high and low-pressure pump element, a common pressure outlet and a switching valve that is arranged between a tank connection and the low-pressure pump element. The switching valve has a spring element and a piston being movable against a force of the spring element relative to the housing and having a closing member that can be lifted from a valve seat by a control pressure that is tapped on the pressure outlet and applied in a control pressure chamber. On the one hand, the invention is characterized in that the switching valve comprises a tappet that is movable relative to the housing and configured to move the piston and arranged between the control pressure chamber and the piston and has a smaller effective diameter than the piston. On the other hand, the invention is characterized in that the dual-stage pump comprises at least one valve that can be screwed into the housing, wherein a cutting edge of the valve is sealingly cut into the housing.

Dependencies are inferred from the claim text.