Adjustable rotary pump with reduced wear

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 at least one of the first actuating member sliding surface and the first track;
• 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;
• at least one of the second actuating member sliding surface of the second actuating member and the second track consists of the sliding material;
• wherein the sliding material is a thermoplastic modified with a lubricant;
• wherein the sliding material is a polymer compound of at least one heat-resistant polymer filled with carbon fibers and a sliding additive comprising at least one of graphite and fluoropolymer.