Abstract: A pump apparatus for an electrohydraulic power steering mechanism for a vehicle includes a hydraulic pump, a working line, a pressure generator, a first control line, a preliminary pressure line, a compensation tank, a shut-off valve having a control inlet, and a second control line. The hydraulic pump is designed to pump a hydraulic oil out of a pump chamber to a pump outlet of the hydraulic pump. The pressure generator has a pressure generation inlet and a pressure generation outlet, and the pressure generator is designed to generate, using an inlet pressure present at the pressure generation inlet, an outlet pressure which can be provided at the pressure generation outlet and is lower than the inlet pressure. As a result, a preliminary pressure can be generated in the pump chamber.

Abstract: An electrohydraulic power steering device for a vehicle includes a hydraulic pump, a drive, a first working line, a second working line, and a heat exchanger. The hydraulic pump is designed, in a first rotation direction, to pump a hydraulic oil to a first pump output of the hydraulic pump and, in a second rotation direction, to pump said oil to a second pump output of the hydraulic pump. The drive is coupled to the hydraulic pump and is designed to drive the hydraulic pump selectively in the first rotation direction or second rotation direction. The first working line is shaped to connect the first pump output fluidically to a first working chamber, the first working chamber being suitable for moving a piston, which is couplable to a steering bar of a steering system, in a first direction. The heat exchanger is designed to transfer heat that is generated during operation of the drive to at least one of the working lines in order to heat the hydraulic oil flowing through the working line.