Pump assembly for a pump, pump, and method for reducing or eliminating disturbing noises and / or vibrations in pumps

Abstract

What is illustrated and described is a pump assembly (1) for a pump, particularly for a miniature pump, with an electric motor (2) and with a housing unit (3), wherein the electric motor (2) has a motor shaft (5) passing freely through a motor housing of the electric motor (2) and the motor housing is connected to the housing unit (3), and wherein the motor shaft (5) is supported in the motor housing with an axial shaft play. According to the invention, at least one stabilizing element (6, 13, 14, 16) arranged outside of the motor housing is provided in order to reduce or eliminate the axial play of the motor shaft (5), with an axial compressive force or axial tensile force acting on the motor shaft (3) being applied by the stabilizing element (6, 13, 14, 16) to the motor shaft (5).

Claims

1. An eccentric diaphragm pump with a diaphragm and a pump assembly, wherein the pump assembly comprises an electric motor and a housing unit, wherein the electric motor has a motor shaft passing freely through a motor housing of the electric motor and the motor housing is connected to the housing unit, and wherein the motor shaft is supported in the motor housing with an axial shaft play, wherein the electric motor with motor shaft and motor housing forms an independent structural unit, wherein a majority of the motor shaft extends within the motor housing, but one freestanding shaft end of the motor shaft is passed through an outer wall or front side of the motor housing into an interior space of the housing unit, so that the freestanding shaft end of the motor shaft is completely enclosed by the housing unit, wherein the motor shaft is connected to an eccentric within the housing in a torque-proof manner, wherein the eccentric is also connected by a ball bearing to a connecting rod in order to establish a connection to the diaphragm and to ensure pump function, wherein at least one stabilizing element arranged outside of the motor housing is provided in order to reduce or to eliminate the axial shaft play of the motor shaft, wherein an axial compressive force or axial tensile force acting on the motor shaft is applied by the at least one stabilizing element to the motor shaft, wherein the at least one stabilizing element is provided so that it is fastened in the housing unit, wherein the at least one stabilizing element is arranged in a housing part of the housing unit and wherein a first portion of the at least one stabilizing element is fixed by the housing part in an orientation axially opposite from the freestanding shaft end of the motor shaft.

2. The pump assembly as set forth in claim 1, wherein a second portion of the at least one stabilizing element is provided so that it is rotatably connected to the motor shaft.

3. The pump assembly as set forth in claim 1, wherein, in order to reduce or eliminate the axial play of the motor shaft, a magnetic coupling is provided between the motor shaft and the housing unit and/or between the motor shaft and the motor housing.

4. The pump assembly as set forth in claim 1, wherein a permanent magnet is provided as the at least one stabilizing element or the at least one stabilizing element includes at least one permanent magnet.

5. The pump assembly as set forth in claim 1, wherein, in order to create a magnetic coupling, at least two magnetic stabilizing elements act together or the at least one stabilizing element acts together with a region or portion or part of the housing unit or of the motor housing or of the motor shaft that is made of a ferromagnetic material.

6. A pump with the pump assembly as set forth in claim 1, wherein the pump is a pump with a delivery volume of less than 10 L/min.

7. A pump with the pump assembly as set forth in claim 1, wherein the pump is a pump with a delivery volume of less than 1000 mL/min.

8. A pump with the pump assembly as set forth in claim 1, wherein the pump is a pump with a delivery volume of less than 500 mL/min.

9. A method for reducing or eliminating vibrations and/or noises in eccentric diaphragm pumps, comprising a diaphragm and a pump assembly with an electric motor and with a housing unit, wherein the electric motor has a motor shaft passing freely through a motor housing of the electric motor and the motor housing is connected to the housing unit, and wherein the motor shaft is supported in the motor housing with an axial shaft play, wherein the electric motor with motor shaft and motor housing forms an independent structural unit, wherein a majority of the motor shaft extends within the motor housing, but one freestanding shaft end of the motor shaft is passed through an outer wall or front side of the motor housing into an interior space of the housing unit, so that the freestanding shaft end of the motor shaft is completely enclosed by the housing unit, wherein the motor shaft is connected to an eccentric within the housing in a torque-proof manner, wherein the eccentric is also connected by a ball bearing to a connecting rod in order to establish a connection to the diaphragm and to ensure to pump function, wherein the method includes the step of providing an axial compressive force or axial tensile force from outside of the motor housing on the motor shaft with at least one stabilizing element in order to reduce or eliminate the axial shaft play, wherein the at least one stabilizing element is provided so that it is fastened in the housing unit, wherein a first portion of the at least one stabilizing element is arranged in a housing part of the housing unit and wherein the at least one stabilizing element is fixed by the housing part in an orientation axially opposite from the freestanding shaft end of the motor shaft.

10. The method of claim 9, wherein the pump assembly is a pump with a delivery volume of less than 10 L/min.

11. The method of claim 9, wherein the pump assembly is a pump with a delivery volume of less than 1000 mL/min.

12. A diaphragm pump with a diaphragm and a pump assembly, wherein the pump assembly comprises an electric motor and a housing unit, wherein the electric motor has a motor shaft passing freely through a motor housing of the electric motor and the motor housing is connected to the housing unit, and wherein the motor shaft is supported in the motor housing with an axial shaft play, wherein the electric motor with the motor shaft and motor housing forms an independent structural unit, wherein a majority of the motor shaft extends within the motor housing, but one freestanding shaft end of the motor shaft is passed through an outer wall or front side of the motor housing into an interior space of the housing unit, so that the freestanding shaft end of the motor shaft is completely enclosed by the housing unit, wherein the diaphragm is driven by the motor shaft within the housing unit in order to ensure pump function, wherein at least one stabilizing element arranged outside of the motor housing is provided in order to reduce or to eliminate the axial shaft play of the motor shaft, wherein an axial compressive force or axial tensile force acting on the motor shaft is applied by the at least one stabilizing element to the motor shaft, wherein the at least one stabilizing element is provided so that it is fastened in the housing unit, wherein the at least one stabilizing element is arranged in a housing part of the housing unit and wherein a first portion of the at least one stabilizing element is fixed by the housing part in an orientation axially opposite from the freestanding shaft end of the motor shaft.

Description

(1) The invention is illustrated in further detail on the basis of exemplary embodiments.

(2) FIG. 1 shows a schematic view of a first embodiment of a pump assembly according to the invention with a housing unit and an electric motor, with a mechanical coupling being provided between the housing unit and a motor shaft of the electric motor;

(3) FIG. 2 shows a schematic view of a second embodiment of a pump assembly according to the invention with a magnetic coupling between the housing unit and the motor shaft; and

(4) FIG. 3 shows a schematic view of another embodiment of a pump assembly according to the invention with a magnetic coupling between the motor shaft and the motor housing.

(5) FIG. 1 shows a schematic and cutaway illustration of a pump assembly 1 for a miniature diaphragm pump or eccentric diaphragm pump having an electric motor 2 and a multipart housing unit 3. The diaphragm pump is suitable as a drainage pump for suctioning off bodily fluids or gases in the vicinity of a wound, for example. A part of the housing unit 3 forms a housing cover 4. The electric motor 2 has a motor shaft 5 passing freely through a motor housing (not shown in further detail) of the electric motor 2. The electric motor 2 with motor shaft 5 and motor housing forms an independent structural unit, which is shown in an installed position in FIG. 1. The motor housing is screwed to the housing unit 3. It is also not shown that the motor shaft 5 is supported in the motor housing with an axial shaft play; in particular, a slide bearing and not a ball bearing of the motor shaft 5 is provided which can also absorb axial forces.

(6) On a drive side of the electric motor 2, the motor housing has a housing opening for the motor shaft 5 through which the motor shaft 5 is guided. The motor shaft 5 can be supported by means of sintered bearings that are designed merely to absorb radial forces. In such electric motors 2, components can be provided on the motor shaft 5 that rotate together with the motor shaft 5 and act axially against the motor housing or a shaft bearing in the motor housing depending on the arrangement and alignment of the electric motor 2 during pump operation. This can result in bothersome vibrations and noises. As a result of the connection of the electric motor 2 to the housing unit 3, vibrations are transferred to the housing unit 3 and, particularly when it is necessary to arrange the diaphragm pump near the body during pump operation, are perceived as an annoyance.

(7) In order to prevent vibrations and/or noises, for example if the eccentric diaphragm pump is tilted when the motor shaft 5 is moved out of a horizontal position, for example, the depicted pump assembly 1 has a stabilizing element 6 which, in the form of a sphere, acts as a support bearing for the motor shaft 5 and rests against the free end of the motor shaft 5 directly on the front side. The motor shaft 5 is forced by the stabilizing element 6 in the axial direction X (FIG. 1) to the side opposite from the drive side of the electric motor 2 and a pretension is produced in this direction, which results in a reduction of the axial shaft play of the motor shaft 5 in the motor housing.

(8) As can also be seen from FIG. 1, the stabilizing element 6 is held with a diaphragm 7 made of an elastic plastic on the housing cover 4 and pretensioned in the direction of the motor shaft 5. Instead of the diaphragm 7, another spring means can also be provided. The diaphragm 7 is connected to the housing cover 4. In order to prevent the stabilizing element 6 from being pressed into the diaphragm 7 and to thus enable sufficient compressive force to be applied to the motor shaft 5 in the axial direction X in a manner that has long-term stability, a support ring 8 made of metal can be provided, which is placed or pushed into a diaphragm pocket 9.

(9) The motor shaft is connected in a torque-proof manner that is in itself customary to the eccentric 10. The eccentric 10 is also connected by means of a ball bearing 11 in a manner that is in itself customary to a connecting rod 12 in order to establish a connection to a diaphragm (not shown) of the diaphragm pump and ensure the pump function.

(10) FIG. 2 shows an alternative embodiment of a pump assembly 1 of a diaphragm pump. Same reference symbols in FIGS. 1 and 2 designate same components, for which reason reference is made here to the foregoing description of these components.

(11) Unlike the pump assembly 1 depicted in FIG. 1, in order to reduce or eliminate the axial shaft play of the motor shaft 5 according to FIG. 2, a magnetic coupling is provided between a stabilizing element 13 disposed on the inside of the housing cover 4 and another stabilizing element 14 disposed concentrically with the motor shaft 5. The additional stabilizing element 14 can also be arranged so as to be offset in relation to the motor shaft 5 with the additional function of a counterweight. The stabilizing element 13 is preferably a disc magnet. The additional stabilizing element 14 is preferably a ring magnet. Since the stabilizing elements 13, 14 are equally polarized on opposing sides, the motor shaft 5 is repelled by the stabilizing element 13 and thus forced in the direction X to the side of the motor opposite from the drive side of the electric motor 2. This reduces, and preferably completely eliminates, axial bearing clearance of the motor shaft 4 in the motor housing.

(12) Incidentally, it will be readily understood that the stabilizing element 13 and the additional stabilizing element 14 can also be polarized differently on the mutually facing sides, so that the motor shaft 5 is pulled toward the housing cover 4, which, depending on the structural design of the shaft bearing in the electric motor 2, can also result in the reduction, and preferably the complete elimination, of an inherent axial bearing play of the motor shaft 5 within the motor housing.

(13) The additional stabilizing element 14 is integrated into the eccentric 10 on the front side. For this purpose, the eccentric 10 has a corresponding annular groove into which the additional stabilizing element 14 is inserted. The concentric arrangement of the ring magnet contributes to a highly smooth operation on the part of the electric motor 2.

(14) Something that is not shown is that the eccentric 10 can have counterweightswhich can be formed by permanent magnetsarranged so as to be offset on the front side in relation to the motor shaft, with these counterweights being provided as stabilizing elements. A magnetic coupling between the housing unit 3 and the motor shaft 5 can be achieved in this way, too.

(15) It is also possible for only one stabilizing element 13, 14 to be provided that acts together with a ferromagnetic region, portion, or part of the housing cover 4 or of the motor shaft 5. In the embodiment shown in FIG. 2, for example, instead of the stabilizing element 13, a disc made of a ferromagnetic material can be arranged on the inside of the housing cover 4, thus causing the motor shaft 5 to be pulled toward the housing cover 4 counter to the axial direction X shown in FIG. 2. In order to pull the motor shaft 5 in the axial direction X, a commensurately designed ferromagnetic region can also be provided on the motor housing. Alternatively, instead of the additional stabilizing element 14, it is also possible to provide a disc made of a ferromagnetic material connected in an appropriate location to the motor shaft 5, so that the disc and thus the motor shaft 5 is pulled toward the magnetic stabilizing element 13 on the housing cover 4.

(16) Alternatively, a magnetic field can also be generated between a permanent magnet fixed on the eccentric 10 and a permanent magnet fixed on the motor housing in order to reduce or eliminate axial play of the motor shaft 5.

(17) FIG. 3 shows another embodiment of a pump assembly 1 for an eccentric diaphragm pump; here as well, same reference symbols in FIGS. 1, 2, and 3 designate same components, for which reason reference is made here to the foregoing description of these components.

(18) In the embodiment shown in FIG. 3, a disc 15 is provided that is connected securely radially inwardly to the motor shaft 5 and securely radially outwardly to a ring magnet as a stabilizing element 16. The disc 15 is arranged at the free end of the motor shaft 5 guided through the motor housing of the electric motor 2 adjacent to the motor housing. For a magnetic coupling, the motor housing can be made of a magnetizable (ferromagnetic) material. A cover plate or fixing screws or the like can also be made of a magnetizable material. This means that the motor shaft 5 is pulled in the axial direction X to the motor housing, which, in turn, can result in a reduction or the elimination of the inherent axial play of the shaft. Here, too, it will readily be understood that an additional magnetic stabilizing element can be provided in the vicinity of the motor housing in order to attract (or repel) the stabilizing element 16 connected to the motor shaft 5 even more strongly and to bring about a displacement of the motor shaft 5 into one or the other direction.

LIST OF REFERENCE SYMBOLS

(19) TABLE-US-00001 1 pump assembly 2 electric motor 3 housing unit 4 housing cover 5 motor shaft 6 stabilizing element 7 diaphragm 8 support ring 9 diaphragm pocket 10 eccentric 11 ball bearing 12 connecting rod 13 stabilizing element 14 stabilizing element 15 disc 16 stabilizing element