Patent ID: 8186982

Claim:
A rotary pump having a variable delivery volume, comprising: a casing; a delivery chamber formed in the casing and comprising an inlet for a fluid on a low-pressure side and an outlet for the fluid on a high-pressure side of the pump; at least one delivery rotor which can be rotated in the delivery chamber about a rotational axis; a first actuating member which is arranged facing a front face of the delivery rotor, and can be moved back and forth in the casing for adjusting the delivery volume; the first actuating member being chargeable, in the direction of its mobility, with an actuating force which is dependent on a fluid requirement; a first track which is formed in the casing and guides the first actuating member on a first actuating member sliding surface in a sliding contact; a sliding material which forms the first actuating member sliding surface; the first actuating member, a second actuating member and the delivery rotor are part of an adjusting unit which can be moved as a whole back and forth in the casing; the first and second actuating members are each arranged facing one of the front faces of the delivery rotor, and a second track is formed in the casing which guides the second actuating member on its second actuating member sliding surface in a sliding contact; the second actuating member sliding surface of the second actuating member consists of the sliding material; wherein the sliding material is a polymer compound of at least one heat-resistant polymer filled with carbon fibers and a sliding additive comprising graphite and fluoropolymer; wherein the at least one heat-resistant polymer is a polymer including copolymer, a mixture of polymers or a polymer blend from the group consisting of polyether sulphone (PES) and polysulphone (PSU).