Abstract: The invention relates to a power steering pump drive with a single- or two-stage compressor unit; the compressor unit comprises a housing, a piston, a cylinder, a connecting rod, a drive shaft and a crankshaft, further a power steering pump which comprises a housing and a piston; the housing of the power steering pump is flange-mounted to the housing of the compressor unit; the piston of the power steering pump is in drive connection with the crankshaft of the compressor unit. The invention is characterized by the following features: the power steering pump is disposed on the side of the crankshaft which is opposite of the piston of the compressor unit; the drive connection between the crankshaft and the drive shaft of the power steering pump comprises a gear drive; the gear drive is enclosed by the housing for the compressor unit.

Abstract: The invention concerns a combined piston-expander compressor comprising a plurality of pistons (3, 14) which are mechanically coupled together by a piston rod (4), as well as a main slide (6), an auxiliary slide (7) and a control valve (9) for control purposes, characterised in that the main slide (6) is formed from a plurality of slide elements that are not interconnected, two outer slide bodies (6a, 6b) being provided. Control pistons (6c) with control edges and simple slide elements (6d) are arranged in a row between the outer slide elements, in the form of a small piston (6a) and a large piston (6b), such that a differential pressure acting on the outer slide elements (6a, 6b) automatically and mechanically holds together the main slide (6).