Abstract: A device is proposed for centering a bearing bushing on a shaft wherein the bushing is made of a material, such as a ceramic, that is sensitive to tensile stress. At lower operating temperatures the bushing exhibits a degree of play relative to the shaft, but is play-free relative thereto at high operational temperatures. Correct centering of the bushing is ensured even in the higher temperature range by the provision of a pair of centering rings which are connected to the shaft without play and act on the bushing to center it. The centering rings are made of a material which, in comparison to the bushing, is not sensitive to tensile stress. It is expedient to provide the two centering rings at the end faces of the bushing. The clamping action of the centering rings on the bushing assures rotational pull of the bushing at low operating temperatures.

Abstract: A rotary pump assembly including a pump having a pump housing, a pump shaft disposed within the pump housing, a runner mounted concentrically on the pump shaft, a motor having a motor housing, and an intermediate housing interconnected between the pump- and motor-housings. The pump shaft has an end facing the motor, and the pump shaft end is formed as a hollow shaft fittingly mounted on the motor shaft. A bearing support is disposed in the intermediate housing for supporting the hollow pump shaft end, and is formed as an axial bearing with substantially no radial bearing capacity.