Combination of motor and vacuum pump with an exhaust flow

A vacuum pump generates a vacuum, in a suction device, with an air intake device and an air exhaust device, as well as a motor for driving the vacuum pump. The air exhaust device is provided with a discharge valve. The exhaust air is downstream of the discharge valve divided into two partial flows that are respectively associated with a pipe section.

TECHNICAL FIELD

The invention pertains to a vacuum pump, e.g. a rotary vane vacuum pump, for generating a vacuum, e.g. in a suction device, with an air intake device and an air exhaust device, as well as a motor for driving the vacuum pump, wherein the air exhaust device is provided with a discharge valve.

PRIOR ART

Vacuum pumps of the type in question are generally known, e.g. in the form of rotary vane vacuum pumps, as well as in the form of so-called side channel compressors.

Rotary vane vacuum pumps usually consist of a blower with a rotary vane housing that forms a rotary vane chamber realized in the form of a cylindrical bore. The rotary vane rotor is usually realized cylindrically and features vanes that are displaceably arranged in slots of the rotor. Referred to a cross section through the rotor, the slots in the rotor may be strictly aligned radially or include an acute angle with a radial line. According to the prior art, the rotor is preferably supported in the region of the cover or flange, e.g. a motor flange, that respectively forms the termination of the rotary vane housing.

During the operation of the vacuum pump, the rotor rotates radially offset to the center axis of the rotary vane housing. This results in the formation of closed chambers that are separated by the vanes, which essentially can be displaced radially, wherein the size of these closed chambers varies during one revolution of the rotor. These size variations cause pressure differentials between the individual chambers and therefore between the air intake device and the air exhaust device of the pump.

It is furthermore known to provide the outlet side of the pump with a discharge valve, behind which the exhaust air can be discharged into the surroundings if the vacuum pump is realized in the form of a suction device.

SUMMARY OF THE INVENTION

In light of the above-described prior art, the invention is based on the objective of enhancing a vacuum pump of the type in question, particularly with respect to an improved noise emission during the operation of the pump.

According to a first aspect of the invention, the above-defined objective can be attained with a vacuum pump, which is designed such that the exhaust air is downstream of the discharge valve divided into two partial flows that are respectively associated with a pipe section.

According to another aspect of the invention, the above-defined objective can also be attained with a vacuum pump, which is designed such that the discharge valve is arranged above the motor and the vacuum pump referred to a normal operating state of the combination of motor and vacuum pump and that a pipe section, which conveys the exhaust air from the region above the motor and the vacuum pump into a region underneath the motor and the vacuum pump, is connected to the discharge valve, wherein the pipe section is partially or completely arranged within the outside contour of the motor and/or the vacuum pump referred to a cross section perpendicular to a longitudinal axis of the motor and/or pump shaft.

Each individual solution, as well as any possible combination of the individual characteristics, results in a significant reduction of the noise mission in comparison with pumps according to the above-describe the prior art.

In a potential embodiment, the exhaust air may therefore be conveyed through two pipe sections downstream of the discharge valve. For this purpose, a corresponding branch may be provided downstream of the discharge valve referred to the flow direction, if applicable directly downstream of the discharge valve or at a certain distance from the discharge valve. The branch may furthermore be realized within the valve housing containing the discharge valve such that partial flows are directly discharged from the valve housing. The branch particularly may be realized in the form of a bifurcated pipe that is arranged directly adjacent to the discharge valve referred to the flow direction.

In this context, it is furthermore conceivable that the partial flows—and accordingly the corresponding pipe sections—are dimensioned identically, e.g., with respect to the cross-sectional area of the pipe sections viewed transverse to the flow direction and/or the length of the pipe sections viewed in the flow direction. However, different dimensions may also be provided in this respect.

An (additional) noise reduction can be achieved by conveying the exhaust air from the upper region of the vacuum pump, in which the discharge valve is usually arranged, into a lower region that particularly is directed downward in the operating state. Such a vacuum pump can be used, e.g., in medical-technical devices. Since the exhaust air is now discharged underneath the region of the motor and the vacuum pump, it is directed away, in particular, from persons located in the vicinity during the normal operation of the entire device.

A spatially advantageous solution is achieved due to the proposed arrangement of the pipe section within the cross-sectional outside contour of the motor and/or the vacuum pump. Due to this design, the shift of the air outlet from the top to the bottom only adds little or nothing at all to the cross-sectional dimension of the vacuum pump and/or the motor.

If the exhaust air is divided into two partial flows that are respectively associated with a pipe section, both pipe sections preferably can at least essentially extend within the outside contour of the motor and/or the vacuum pump in order to advantageously convey the exhaust air from an upper region into a region underneath the motor and the vacuum pump.

Other characteristics of the invention are frequently explained below, as well as in the description of the figures, in their preferred association with the device and features described herein. However, they may respectively also be important in association with only individual characteristics of the device or other features described herein.

In an enhancement, a pipe section for a partial flow may feature a discharge opening into the surroundings and the discharge opening into the surroundings may respectively be provided with a check valve or discharge valve. The discharge opening into the surroundings can preferably be realized underneath the motor and the vacuum pump. Due to the potential arrangement of an (additional) discharge valve in the region of the discharge opening into the surroundings, valves may in a potential embodiment be provided on both ends of a pipe section arranged downstream of the air exhaust device.

If two pipe sections are provided, each pipe section forms a discharge opening into the surroundings that may be respectively provided with an (additional) discharge valve.

The motor may be realized in the form of an electric motor. This electric motor preferably features a motor flange. The pipe section may be integrated into the motor flange. It is preferred to provide the motor flange formed between the motor and the vacuum pump with the pipe section.

If two pipe sections are provided, both pipe sections may in a potential embodiment be integrated into the motor flange.

In another embodiment, the pipe section may be composed of a partial section in the motor flange and a partial section outside the motor flange. The partial section outside the motor flange may particularly extend between the discharge valve and the partial section in the motor flange. The partial pipe section in the motor flange can preferably feature the discharge opening into the surroundings that, if applicable, is provided with an (additional) discharge valve.

The motor flange may consist of a metallic material. Such a motor flange can be manufactured, e.g., in a sand casting process. The pipe section, particularly the corresponding partial section if another partial section is provided outside the motor flange, may be formed by the metallic material of the motor flange. Accordingly, the pipe section on the flange side is in a preferred embodiment directly formed by the flange material.

The pipe section integrated into the motor flange may particularly extend along a segment of a circle referred to the cross section perpendicular to the longitudinal axis of the motor and/or pump shaft in order to convey the exhaust air from a region above the motor and the vacuum pump into a region underneath the motor and the vacuum pump. The integrated pipe section may furthermore be defined in the form of a segment of a circle, the center of which is associated with the geometric axis of the motor and/or pump shaft.

If two pipe sections are integrated into the motor flange, these pipe sections may in a potential embodiment respectively extend along a segment of a circle such that they essentially are arranged diametrically opposite of one another referred to the shaft axis.

The combination of motor and vacuum pump may be mounted on a base plate that is supported by means of legs. In this way, a unit consisting of the motor and the vacuum pump including the pipe sections within the motor flange can be realized.

The discharge opening of the pipe section may lead into the surroundings underneath the base plate referred to a normal operating state of the combination. In a potential embodiment, the pipe sections or sections connected to these pipe sections such as, e.g., the check or discharge valves may extend through the base plate. The opening plane of the discharge opening preferably extends underneath the base plate at a certain distance from the facing bottom surface of the base plate, wherein said distance may be chosen smaller than twice the largest cross-sectional inside dimension of the pipe section, preferably equal to or smaller than this largest cross-sectional inside dimension of the pipe section.

In a preferred embodiment, in which the base plate is supported on a floor or the like by means of legs, the discharge opening or the discharge openings may respectively lead into the intermediate space resulting from the height of the legs.

The base plate may be supported by means of vibration-cushioned legs. In this way, an additional noise reduction of the entire combination is achieved.

A vibration-cushioned leg may feature an elastomer or rubber part that, e.g., is penetrated by a mounting screw or features a mounting pin, which respectively connects the leg to the base plate.

DESCRIPTION OF THE EMBODIMENTS

A combination of a motor1, particularly an electric motor, and a vacuum pump2, preferably a rotary vane vacuum pump2′ (as shown inFIG. 1a), is initially described with reference toFIG. 1. In the exemplary embodiment shown, this combination is mounted on a base plate3that is supported on the ground by means of legs4.

The vacuum pump2features a pump housing5, in which a rotary vane chamber62with a rotary vane rotor56is arranged. Within the pump housing5is a chamber housing60. With respect to the design and function of the vacuum pump2, we refer to the initially cited literature, e.g. to DE 101 06 111 A1. The content of this patent application is hereby fully incorporated into the disclosure of the present invention, namely also for the purpose of incorporating characteristics of this patent application into claims of the present invention.FIG. 1ashows an embodiment in which the vacuum pump2is a rotary vane vacuum pump2′.

During the operation of the vacuum pump2, the rotary vane rotor56rotates radially offset to the geometric axis x of a motor shaft6. The rotary drive is realized by means of the motor1that rotatively acts upon the pump shaft52. The motor shaft6of said motor longitudinally penetrates a central opening7of a motor flange8arranged between the motor1and the vacuum pump2.

The opening7of the motor flange8may simultaneously serve for supporting the motor shaft6(seeFIG. 5).

The vacuum pump2features an air intake device9and an air exhaust device10associated with the rotary vane chamber62.

The air intake device9may feature a connecting piece11. This connecting piece produces the fluidic connection with the rotary vane chamber62. A suction hose12, e.g. of a rubber material, may be connected to the connecting piece11as indicated.

The air exhaust device10is also fluidically connected to the rotary vane chamber62.

Both thusly formed air intake and exhaust openings of the vacuum pump are positioned above the motor1and the vacuum pump2during the normal operation of the vacuum pump2, particularly the normal operation of the aforementioned combination. Accordingly, the suction hose12of the air intake device9also extends above the vacuum pump2.

A discharge valve13is provided in the region of the air discharge opening of the pump housing5. This valve may consist of a check valve with a valve seat14and a valve disk16that is spring-loaded into a closed valve position by means of a spring15. In a normal position according toFIG. 5, this valve disk is seated on the valve seat14in a sealed fashion. The valve disk16is only raised into an open position according toFIG. 6when a pressure greater than the restoring force of the spring15is exceeded.

The exhaust air is divided into two partial flows in the flow direction (see arrows a inFIG. 6). For this purpose, two pipe sections17and18are arranged downstream of the discharge valve13. The valve cover19that bridges the cooperating region of the valve seat14and the valve disk16may feature corresponding connecting pieces for connecting the pipe sections17and18. The valve cover wall is provided with correspondingly positioned discharge openings20.

The pipe sections17and18convey the partial flows from the region above the motor1and the vacuum pump2into a region underneath the motor1and/or the vacuum pump2(seeFIG. 5).

Each pipe section17,18may be composed of two partial sections that are arranged behind one another in the flow direction as shown. A rigid partial section21,22, which is integrated into the motor flange8, is thereby respectively provided.

The motor flange8may accordingly serve for terminating the motor1on its end face and, if applicable, for supporting the motor shaft6, as well as for conveying the air flow from the discharge valve13arranged on the upper side of the vacuum pump2into a region underneath the motor1and/or the vacuum pump2.

Referred to a cross section transverse to the axis x according toFIG. 5, the motor flange8consisting of a metallic material, which is manufactured, e.g., in a sand casting process, accordingly features two partial sections21,22of the pipe sections17,18, wherein said partial sections respectively extend along a segment of a circle, the center of which is associated with the geometric axis x, such that they lie diametrically opposite of one another referred to the axis x.

The two partial sections21and22end in connecting pieces23,24on the upper side of the motor flange8facing the discharge valve13. Hose pipes25and26that respectively form first partial sections are arranged on these connecting pieces in a fluidically tight fashion. On their ends that face away from the partial sections21and22, these hose pipes are fixed on the valve cover19in association with the discharge openings20.

A hose pipe25or26respectively forms one of the pipe sections17or18together with the corresponding partial section21or22on the flange side.

On the underside of the motor flange8, the partial sections21and22of the pipe sections17and18on the flange side end in downwardly open connecting pieces27,28. The latter respectively form discharge openings29,30into the surroundings, which are respectively provided with an additional discharge valve31,32.

Each discharge valve31,32features a housing with a valve seat33. This housing can be fixed in the associated connecting piece27,28, e.g., by means of a screw joint as shown.

A valve disk34is also guided in the housing and acts against the valve seat33in a sealing fashion in order to close the discharge opening29. The valve disk34is spring-loaded into this valve seat position by means of a spring35, e.g. a cylindrical pressure spring.

The valve disk34may furthermore cooperate with the valve seat33via a sealing layer36as shown. The sealing layer36may consist, e.g., of a felt layer.

The air discharge opening plane E resulting in the region of the valve seat33can preferably extend underneath the base plate3that carries the combination of motor1and vacuum pump2(see especiallyFIG. 9). For this purpose, the partial sections21and22on the flange side or their connecting pieces27,28with the discharge valves31,32respectively extend through correspondingly positioned passage openings45in the base plate3(seeFIG. 9).

The base plate3may consist, e.g., of a formed sheet steel component. The combination is mounted thereon, particularly by means of screws. For this purpose, only a screw joint in the region of the connecting pieces27and28on the motor flange side may be provided as shown (seeFIG. 8). The corresponding screws are identified by the reference symbol37.

The motor1and the vacuum pump2are mounted on the motor flange8such that a stable combination of motor1and vacuum pump2is achieved. Due to the support of the entire combination on the base plate3by means of the motor flange8, the motor1and the vacuum pump2may extend at a (vertical) distance from the facing surface of the base plate3.

The base plate3realized, if applicable, in the form of a sheet metal component is supported on a surface such as, e.g., a floor39by means of the legs4. The figures show an arrangement of four legs4in the respective corner regions of the base plate3, the horizontal projection of which otherwise has an elongate rectangular shape.

The legs4are vibration-cushioned. They essentially consist of an elastomer material or a rubber material. According to the figures, a solid rubber or a solid elastomer material is essentially provided, wherein each leg4has an altogether diabolo-shaped design with two parallel end faces that are vertically spaced apart from one another in the operating position and between which the material extends such that a constriction is formed.

A disk38of a hard material, e.g. of metal or hard plastic, may be respectively inserted in the region of the end faces as shown and encased with the elastomer or rubber material by means of injection molding.

In the preferred rotationally symmetrical design of a leg4, each disk38is likewise realized circularly.

The support on the underside of the base plate3is realized by means of the end faces, particularly the disks38, and the support on the ground39, e.g. on the bottom of a movable frame or the like, is realized by means of the downwardly directed end face.

Each leg4is mounted on the base plate3in association with a mounting opening40, preferably in a captive and operatively inseparable fashion. The figures show a mounting41in the form of a rivet joint.

The base plate3with the combination of motor1and vacuum pump2mounted thereon can be supported on the ground39in a vibration-cushioned fashion by means of the legs4.

In this context, it is furthermore conceivable, for example, to mount this unit consisting of the combination and the base plate3with the legs4on the ground39, wherein the bottom disk38of a leg4is for this purpose held in the leg4such that it extends through a threaded sleeve42and is encased with the elastomer or rubber material by means of injection molding in order to cooperate with a screw44that is screwed through the ground39from underneath in the region of bores43.

All disclosed characteristics are essential to the invention (individually, but also in combinations with one another). The content of the associated/attached priority documents (copy of the priority application) is hereby fully incorporated into the disclosure of this application, namely also for the purpose of incorporating characteristics of these documents into claims of the present application. The characteristics of the dependent claims characterize independent inventive enhancements of the prior art, particularly for submitting divisional applications on the basis of these claims.