Rotary pump assembly

#The invention relates to a rotary pump assembly consisting of a pump with a pump housing, a pump shaft and at least one runner, of a motor with a motor housing, and of a motor shaft coaxial to the pump shaft, and of an intermediate housing, rigidly connected with the pump housing and the motor housing, whereby the end of the pump shaft on the side of the motor formed as a hollow shaft is fittingly mounted on the motor shaft and abutted by the support arrangements provided in the intermediate housing. The expression "rotary pump" is applied in the present connection for all pumps, in which a liquid or gaseous medium is conveyed by a rotary action of a runner in a housing, preferably, however, for those pumps whose pump shaft has to receive certain axial forces, which is particularly the case in centrifugal pumps and in some side channel- or water-ring pumps.

#Rotary pump assemblies are known, wherein the runner of the pump is mounted on the end of the motor shaft. These pump assemblies have the disadvantage, that motors with a special shaft must be used, and that the motor bearings must be implemented in a strengthened manner for receiving the pump forces.

#There are also known rotary pump assemblies, where the pump shaft implemented as a hollow shaft is mounted on the normally short stub shaft of the motor and is supported by the same, without requiring any additional bearing (U.S. Pat. No. 2,291,346). This implementation has also the disadvantage, however, that the bearings of the motor must be implemented in a strengthened manner for receiving the pump forces. Such special implementations of drive motors are expensive and make procurement of spare parts more difficult.

#The sole FIGURE shows a longitudinal section of an embodiment according to the invention.

#An electric motor disposed in a housing 1 has an assembly flange 2, on which the appropriate flange 3 of an intermediate housing 4 is attached by screws (not shown). A pump housing 6 is attached to a flange 5 of the intermediate housing by means of screws (not shown). The motor and the pump housing are substantially aligned.

#The normally short-formed stub shaft 7 of the motor shaft projects from the motor 1 into the intermediate housing 4. The end of the pump shaft 9 formed as a hollow shaft 8 is mounted on stub shaft 7 with a tight fit (play-fit) and secured therewith in a rotationally secured manner by means of groove or slot 10. On the end of the pump shaft remote from the pump there is mounted a rotor or runner 11. A radially acting auxiliary support bearing 13 for the pump shaft, shown in dot-dashed outline, may also be provided on a side remote from the motor in the suction opening 12 of the pump. The pump housing 6 does not contain any other support for the pump shaft except for bearing 13. The pump housing 6 contains suction-and pressure supports and is closed off on the pressure side by a housing portion 19. Numeral 14 indicates a sealing which has no bearing-support function.

#A seat in an form of a bore 16 for the axial support bearing 17 is formed in an inwardly projecting portion 15 of the intermediate housing 4, which is axially fixed both with respect to the intermediate housing, as well as with respect to the hollow shaft 8. Between the outer periphery of the axial support bearing 17 and the bore 16 there is disposed an elastic and soft ring-shaped intermediate layer 18, which, for example, may consist of soft rubber. It permits radial movement of the axial support bearing 17 for equalization of any alignment errors with respect to the motor, and damps any possible vibrations. Alternatively, the intermediate layer 18 may be omitted. The axial support bearing is then movable freely in a radial direction.