Abstract: A pumping unit having a pump chamber with a rotor mounted in a rotatable manner within the chamber. The pumping chamber is formed by a circumferential wall and two end walls. The circumferential wall is formed on an annular collar of a pump part and has on its inner surface a track on which sealing bodies of a rotor roll. To avoid deformation of the pump part by hydraulic forces or by pressing-in forces, ribs are arranged on the outer surface of the circumferential wall which extend away from the pump chamber. A shoulder is arranged on the side of the end wall which is directed away from the pump chamber. The shoulder is connected by a press fit to the pump housing and has thin walls so that pressing forces do not result in any deformation to the end wall of the pump chamber.

Abstract: A pumping unit having a pump chamber in which a rotor is mounted in a rotatable manner, and which is formed by a circumferential wall and two end walls, is already known. The circumferential wall is formed on an annular collar of a pump part and, on the inside, forms a track on which sealing bodies of a rotor roll. The track of the pump chamber is subjected to high compressive loading which, if the pump part is made of plastic, may result in the track rupturing. In the case of the pumping unit according to the invention, the pump part is improved in respect of strength and service life. Deformation of the pump part by hydraulic forces or by pressing-in forces is avoided.

Abstract: A roller cell pump having a shaped sliding surface composed of elliptical portions results from two different equations. The function of the unit is improved because the equations are modified and include adaptable parameters, so that by adaptation of the parameters, the shaped sliding surface can be adapted in portions optimally to the requisite function in that particular region of the shaped sliding surface, for instance the function of generating an underpressure or an overpressure. The course of the radii of the elliptical portions corresponds, at least in portions, to one of two equations that differ from the prior art.

Abstract: A roller cell pump having a shaped sliding surface composed of elliptical portions results from two different equations. The function of the unit is improved because the equations are modified and include adaptable parameters, so that by adaptation of the parameters, the shaped sliding surface can be adapted in portions optimally to the requisite function in that particular region of the shaped sliding surface, for instance the function of generating an underpressure or an overpressure. The course of the radii of the elliptical portions corresponds, at least in portions, to one of two equations that differ from the prior art.