EP0964159A2 - Gerotor pump - Google Patents

Abstract

The pump has a housing (3) with cylindrical chamber (5) containing a gerotor set (9) with outer rotor. An anti friction bearing or slide bearing element (90) for radial bearing of the outer rotor in the chamber, is positioned between the radially opposite circumferential surfaces (6) of chamber and rotor. The anti friction bearing may be a roller bearing, ball bearing, or needle bearing. The slide bearing element may be carbon fiber and/or plastic and/or ceramics. The part of the pump housing forming the circumferential chamber surface, and the gerotor set are of stainless steel.

Description

The invention relates to a gerotor pump for liquid media with a Pump housing, a cylindrical chamber in the pump housing, a gerotor barrel set accommodated in the cylindrical chamber, the is driven by a pump drive shaft to rotate the pumping liquid from a suction connection of the pump into one Intake area of the chamber and the pumped liquid from a discharge area of the chamber to a pressure port drive out, wherein the gerotor rotor set an outer rotor with one of the Circumferential surface of the chamber radially facing outer peripheral surface having.

The gerotor pumps are valve-free, compact, self-priming Pumps with positive displacement, which are continuous Generate pump flow with a minimum of pressure fluctuations.

The gerotor liquid pumps have a gerotor pump set, which consists of a ring rotor rotatably mounted in the cylindrical chamber or external rotor with internal teeth and one from the pump drive shaft rotating driven inner rotor with external teeth exists, the number of teeth of the inner rotor is 1 less than that Number of teeth on the outer rotor. The axis of rotation of the inner rotor runs parallel to the axis of rotation of the outer rotor with an eccentric offset, so that the inner rotor driven by the pump drive shaft only in one certain angular range in the circumferential direction of the chamber meshing in the Interlocking of the outer rotor engages to the Gerotor-Laufsatz to To drive rotation. As soon as two adjacent teeth of the inner rotor come out this angular range of meshing engagement in the direction of rotation are moved out between these teeth and two adjacent teeth of the outer rotor over a further rotation a space enlarging a suction angle area of the chamber, the teeth of the inner rotor being the teeth of the outer rotor hurry ahead. After the space has reached a maximum volume , it will rotate over an ejection angle range of Chamber again smaller until the teeth of the inner rotor back into the Angular range of meshing engagement of the outer rotor come. The suction angle range of the chamber is via a suction slot e.g. in one the chamber on the opposite side of the pump drive Side closing cover with a suction connection in connection. The discharge angle range of the chamber is above one Ejection slot in connection with a pressure connection, so that when rotating a flow from the suction connection to the pressure connection the pump is generated.

Gerotor pumps are often made from a single pump housing Made of brass material or bronze and with a gerotor barrel set Stainless steel. In the known gerotor pumps, the outer rotor is of the gerotor barrel set directly in the cylindrical chamber of the Housing mounted so that it with its outer peripheral surface on the Circumferential surface of the chamber slides during pumping. The problem the friction that occurs between the pump housing and the An outer rotor has been attempted to be solved by making a small one Radial play between the outer circumference of the outer rotor and the circumferential surface approved by the Chamber. When the pumps are heavily used and especially at high pump speeds, however, the Problems of abrasion, heating by friction and development from intense operating noises.

The invention has for its object a gerotor pump of the beginning to improve the type mentioned in such a way that it can also be Excellent pump running properties over a long period Has lifespan.

To solve this problem, the invention proposes that between the radially opposite circumferential surfaces of the Chamber and the outer rotor a roller bearing or a plain bearing element Storage of the outer rotor is arranged in the chamber.

The invention treads the unusual path, one Integrate the bearing arrangement into the chamber for the gerotor barrel set. The Rolling bearing or plain bearing element reduces that for pumps according to the state effects of abrasion and heating observed in technology Friction to a considerable extent, the pump according to the invention excellent running properties with significantly reduced operating noise having. It has been shown that the arrangement of the Rolling bearing or plain bearing element in the chamber for the gerotor barrel set no adverse effects on pump performance properties or has pump characteristics.

If the variant with the roller bearing is selected, this can e.g. a Ball bearings, roller bearings or needle bearings. The outer ring of the rolling bearing lies on the peripheral surface of the cylindrical chamber, whereas the Inner ring of the rolling bearing on the outer circumference of the outer rotor of the Gerotor treadmill sits. It is also a version of a rolling bearing without Inner ring conceivable, in which case the rolling elements directly on the run according to the prepared circumferential surface of the outer rotor.

If the variant with the plain bearing element is selected, it can in the case of the plain bearing element, for example, around an annularly closed one or act bearing bush composed of bearing shells whose Bearing surface made of a sliding material with a low coefficient of friction consists. As materials for the slide bearing element come preferably Plastics, carbon fiber materials and / or ceramic materials in Question. Very good experiences were made with a plain bearing element Made Teflon.

According to a preferred variant of the gerotor pump with slide bearing element the slide bearing element is a slide film that has been inserted into the chamber is and extends in the circumferential direction of the chamber. The slide film can e.g. consist of at least one of the aforementioned materials. The Embodiment with sliding film is characterized in that it Manufacturing expenditure of the pump almost not increased at all, therefore is particularly inexpensive and yet the tasks sought after Features of the low-friction, quiet run.

According to a further embodiment, several can be in the circumferential direction the chamber distributed ring segment-like plain bearing elements be provided.

Manufacturing advantages also offer a solution in which the Plain bearing element one on the chamber peripheral surface or on the outer rotor peripheral surface adhesive sliding material layer. Of course can both on the chamber circumferential surface and on the outer rotor circumferential surface in each case such a layer of sliding material is adhered have been.

Although the pump housing and the gerotor runner set are different Materials, especially metals, can be formed, so is according to a preferred embodiment of the gerotor pump according to the Invention proposed that at least the chamber peripheral surface forming part of the pump housing and the gerotor rotor set from one stainless steel (stainless steel) are formed.

Very good results are obtained with a gerotor roller set made of borated Steel reached.

According to a further preferred embodiment of the invention, the Gerotor barrel set made from silicon carbide. It can be provided be that the barrel set on its outer circumference and possibly on its Provide end faces with sliding surfaces, such as a sliding film attached to them is.

In another aspect of the invention, the Task with a gerotor pump with the features mentioned above proposed that in the cylindrical chamber at least one thrust bearing in the form of a roller bearing or a plain bearing element for axial Storage of the gerotor barrel set is provided.

Preferably there is a respective one on both end faces of the gerotor barrel set Thrust bearings in the form of a roller bearing or plain bearing element for axial Storage of the gerotor barrel between the gerotor barrel and the provided axially delimiting surfaces of the pump housing. Special advantages with regard to the improvement of the pump running properties and the increase in the life of the pump arise when in addition to the above-mentioned thrust bearing arrangement Radial bearing according to one of claims 1 - 7 for the gerotor in the cylindrical chamber is provided, which should not be excluded that the axial bearing and the radial bearing of the gerotor barrel set by means of a combined bearing, such as an angular contact ball bearing or both axial forces and radial forces absorbing slide bearing element he follows.

A gerotor liquid pump according to the invention may depend on the desired pump power e.g. with engine speeds between 50 and 6000 rpm can be operated. It is suitable for pumping thin liquids Media such as water, beverages, fuel, HFA hydraulic fluid and the like, although it is not excluded that they are also used as mineral oil pumps can be used. It can therefore be used both in the industrial sector can also be used in the private household sector.

If the pump is used in the food sector, for example for beverage dosing, To be used is to use food safe Materials for those coming into contact with the pump medium Pay attention to pump components.

Fig. 1a

zeigt ein erstes Ausführungsbeispiel der Erfindung in einer Längsschnittdarstellung.

Fig. 1b

zeigt einen Anschlußdeckel der Gerotor-Flüssigkeitspumpe aus Fig. 1a in ausgebautem Zustand in einer Draufsicht (gemäß Fig. 1a von links) auf eine mit einem Pumpenkammergehäuse zu verbindende Stirnseite, wobei ein Bereich herausgebrochen dargestellt ist.

Fig. 1c

zeigt eine Draufsicht auf eine Stirnseite des Pumpenkammergehäuses der Pumpe nach den Fig. 1a und 1b.

Fig. 1d

zeigt eine der Fig. 1c entsprechende Ansicht des Pumpenkammergehäuses, wobei jedoch der Gerotor-Laufsatz ausgebaut ist.

The invention is explained in more detail below using an exemplary embodiment with reference to the figures.

Fig. 1a

shows a first embodiment of the invention in a longitudinal sectional view.

Fig. 1b

shows a connection cover of the gerotor liquid pump from Fig. 1a in a disassembled state in a plan view (according to Fig. 1a from the left) of an end face to be connected to a pump chamber housing, an area being shown broken away.

Fig. 1c

shows a plan view of an end face of the pump chamber housing of the pump according to FIGS. 1a and 1b.

Fig. 1d

1c shows a view of the pump chamber housing corresponding to FIG. 1c, but with the gerotor barrel set removed.

In Fig. 1a is a preferred embodiment of the invention in one Longitudinal representation shown.

The gerotor pump 1 has a pump chamber housing 3 with a circular cylindrical one Recess 5 on the connection face 7 of the pump chamber housing 3. The circular cylindrical recess 5 forms a chamber in which Gerotor running set 9 to be explained, which of a drive shaft 11 of a drive motor 13 is driven in rotation. The drive motor 13 is with its housing 15 directly on the Connection end face 7 opposite end face 17 of the pump chamber housing 3 arranged. The shaft 11 extends through the bore 19 through into the chamber 5 of the pump chamber housing 3. On the front side 17 of the pump chamber housing 3 is the annular gap 21 between the shaft 11 and the circumference of the bore 19 through a shaft seal 23 for Motor 13 sealed off.

In the chamber 5 is an inner ring or inner rotor 25 of the gerotor barrel set 9 via a coupling 27, e.g. a key or the like, for common Rotation coupled to the shaft 11, wherein the inner ring 25 coaxial with Shaft 11 arranged on the pump-side end portion of the shaft 11 is. The gerotor rotor 9 is within its axial play on the shaft 11 held axially movable.

On the connection face 7 of the pump chamber housing 3 is a the recess 5 extending terminal cover 29 is provided, the has a suction port 31 and a pressure port 33. Of the Suction port 31 is in the form of a ring segment-like recess in the Connection cover 29 formed suction kidney 35 with a suction area 37 of the chamber 5 in connection, whereas the pressure connection 33 via one as a ring segment-like recess in the connection cover 29 formed ejection kidney 39 with an ejection region 41 of the chamber 5 communicates.

It can be seen from FIG. 1 b that the suction kidney 35 of the exhaust kidney 39 diametrically opposite.

To explain the structure and function of the gerotor pump runner 9, reference is made below to FIG. 1c. 1c shows in a (not to scale) top view of the connection face 7 of the Pump chamber housing 3 provided with external teeth and driven by the shaft 11 inner rotor 25 within one with a Internal toothing formed outer rotor 43. The outer rotor 43 is in the cylindrical chamber 5 is rotatable essentially coaxially to the chamber 5 stored, the common axis of the chamber 5 and the outer rotor 43 parallel to the common axis of the shaft 11 and the inner rotor 25 is offset. It should also be noted that the internal teeth of the Outer rotor 43 has one tooth more than the external toothing of the Eccentric to the outer rotor 43 arranged inner rotor 25. The position the suction kidney 35 provided in the connection cover 29 and the Position of the ejection kidney 39 provided in the connection cover 29 are approximately indicated at 35 and 39 in projection.

When the inner rotor 25 rotates, it occurs due to the mutual Engagement of the teeth of the inner rotor 25 and the outer rotor 43 for Rotation of the outer rotor 43. As can be seen from the snapshot according to FIG. 1c, the teeth of elements 25 and 43 only overlap a certain angular range - in Fig. 1c on the left side - completely into each other, whereas in a diametrically opposite one Angular range - in Fig. 1c on the right side - the teeth of the inner rotor 25 and the teeth of the outer rotor 43 do not engage in one another. In the Rotation of the gerotor barrel 9, it happens that the teeth of the Inner rotor 25, the teeth of the outer rotor 43 in the latter Overtake the angular range in the direction of rotation. When unscrewing from the the first mentioned angular range of the engagement of the gears each between two adjacent teeth of the inner rotor 25 and two adjacent teeth of the outer rotor 43 a with further rotation moving and increasingly enlarging space 45a and 45b or 45c, which then approaches the first-mentioned angular range the engagement of the gearing becomes smaller again and finally disappears. During the phase of the growing of the concerned Intermediate space runs past the suction kidney 35, so that at the Suction port 31 supplied liquid in the space in question 45 is sucked. During the phase of downsizing the Interspace 45 runs past the discharge kidney 39, so that the Liquid pressed over the discharge kidney 39 to the pressure connection 33 becomes. In this way, by rotating the shaft 11, a continuous Pump operation can be realized.

According to the invention between the peripheral surface 6 of the chamber 5 and Outer peripheral surface 8 of the outer rotor 43 a (shown schematically) Radial bearing 90 arranged. This can be a roller bearing, For example, ball bearings with one fitted in the chamber and on the Circumferential surface 6 of the chamber adjacent outer ring, one on the Outer rotor of the gerotor barrel 43 seated inner ring and with Balls as rolling elements between the inner ring and the outer ring, act. Alternatively, the radial bearing 90 can be a slide bearing element, for example, a slide film appropriately inserted into the chamber 5 or an annularly closed plain bearing bush made of carbon fiber material, Ceramic material or plastic, in particular Teflon, may be formed.

It is achieved with simple means that a desired performance characteristic can be adjusted and maintained. To this The purpose is a spring-loaded pressure relief valve or pressure relief valve 47 provided in a channel 49 which is formed in the connection cover 29 is and the suction port 31 and the suction kidney 35 with the Pressure port 33 or the discharge kidney 39 connects. The valve body 51 of the pressure relief valve 47 can against the force of the spring 53 to the suction side (Intake kidney 35) open, depending on the pressure in the Area of the pressure connection 33 or the discharge kidney 39. The pressure relief valve 47 then conducts liquid from the pressure side (at 39) to Suction side (at 35). According to the characteristic of the spring 53 and Valve construction can maintain a desired performance characteristic be that the valve at certain pressures on the Pressure side only opens so far that excess flow rate over the Channel 49 reaches the suction side and the pump in the rest of the relevant pressure on the pressure side desired flow rate accordingly the desired performance characteristics via the pressure connection to promote "consumer". The spring 53 can, if necessary, against one Spring with a different characteristic. Furthermore, that has Valve 47 functions as an overpressure safety device. When you reach one predetermined maximum pressure opens the valve to maximum passage, so that the channel 49 forms the main flow path and the pump from the Conveying pressure side all the way to the suction side.

A desired performance characteristic can thus be maintained, the pressure relief valve 47 also as a pressure relief device for the pump 1 works.

Provided that one adheres to the particularly advantageous function the desired performance characteristic, the valve 47 alternatively, be designed so that it is only the function of overpressure protection Fulfills.

The valve spring 53 is supported on the one hand on a shoulder 55 of the valve body 51 - and on the other hand on a screw 57, which in a Threaded bore 59 of the connection cover 29 is screwed in.

At 61 in Fig. 1a is a valve lifter connected to the valve body 51 shown, with its end remote from the valve body 51 in a Bore 63 of the screw plug 57 is guided.

A particular advantage of the gerotor pump 1 according to the invention is that that despite their simple and compact construction for pumping Water or similar low-viscosity media with pump pressures up to 60 - 70 bar and pump speeds up to 6000 rpm can be used. The Pump 1 according to the invention also has permanent high-performance operation excellent running properties and a long service life and is also easy to maintain.

The problem of sealing the pump chamber housing 3 to the side Drive motor 13 is with the pump 1 according to the invention with very simple means using commercially available shaft seals 23 been solved.

As shown in FIGS. 1a and 1d, in the pump chamber housing 3 in an annular groove 68 is provided at a small axial distance from the chamber 5, which surrounds the motor shaft 11. This annular groove 68 stands with a recess 70 in the bottom of the chamber 5 in connection, the recess 70 in the Angular range of the chamber 5 runs, which forms the suction area and over which the suction kidney 35 extends. Preferably, the Recess 70 a kidney shape corresponding to the suction kidney 35 and lies - seen axially - in alignment with the suction kidney 35.

This simple construction has the effect of leakage in the small annular gap 72 (gap size e.g. 0.2 - 0.4 mm) between the Drive shaft 11 and the bore 19 pressure occurring (approximately Operating pressure) via the annular groove 68 and the kidney-shaped recess 70 Suction side of the chamber 5 is reduced so far that in the area between the annular groove 68 and the commercially available shaft sealing ring 23 only a low residual liquid pressure, for example 0 - 0.1 bar is present, of the sealing ring 23 without any sealing problems can be included, especially since commercially available shaft seals for Pressures of 0.5 - 30 bar are available.

In the embodiment of FIGS. 1a - 1d it should be emphasized that it is not necessary to implement the reduction of the leakage fluid pressure, Provide leakage fluid channels in the drive shaft 11, so that also in this respect a contribution to the simplification of the pump construction without impairment efficiency is given.

Contributes to the excellent running properties of the gerotor pump 1 in that the drive motor 13 directly on the housing block 3rd is arranged and with its comparatively short motor shaft 11 den Gerotor drive set 9 drives. The exploitation of the motor shaft 11 immediately as a pump shaft avoids the usual shaft couplings between Pump shaft and a separate motor shaft. With the gerotor pump 1 According to the invention, the drive shaft 11 can easily under Avoiding expensive shaft bearings centered within the pump housing 3 be so that low-wear operation is guaranteed. Since the Running set 9 is supported radially by the bearing element 90 and the drive shaft 11 engages centered in the barrel 9, an additional is unnecessary Bearing of the drive shaft 11 or a separate bearing arrangement for the Shaft 11 in the pump housing 3. The immediate attachment of the housing of the drive motor 13 to the pump housing 3, 29 also leads to the fact that a compact, space-saving unit consisting of pump and Drive receives, with the measures mentioned above to dismantle the Make sure that the leakage fluid pressure is low Pump medium cannot penetrate the motor housing.

The relative orientation and centering of the motor 13, the pump chamber housing 3 and the connecting cover 29 to each other and the common These elements are attached to one another by the screw arrangements 74, the elements 13, 3 and 29 in the axial direction enforce and fix each other reliably and in the correct position.

In the context of the invention it can alternatively be provided that the Motor housing and the pump chamber housing to an integral Housing unit are summarized.

It is still to be added that between the connection cover 29 and the Connection face 7 of the pump chamber housing 3 an O-ring seal 76 is provided radially outside the chamber 5.

In another aspect of the invention, alternatively to that Radial bearing 90, but preferably in addition to the radial bearing 90, a (Not shown) thrust bearing assembly for the gerotor 9 in the cylindrical chamber 5 may be provided. The thrust bearing arrangement can Rolling bearings and / or plain bearing elements between which the cylindrical Chamber 5 axially delimiting surfaces 65 and 66 and each comprise opposite end faces of the gerotor rotor 9.

Claims (10)

Gerotor pump for liquid media with a pump housing (3, 29), a cylindrical chamber (5) in the pump housing (3, 29), a gerotor rotor set (9) accommodated in the cylindrical chamber (5) and which is to be driven in rotation by a pump drive shaft (11) in order to draw the liquid to be pumped from a suction connection (31) of the pump into a suction region of the chamber (5) and to expel the suctioned pump liquid from an ejection region of the chamber (5) to a pressure connection (33), the gerotor rotor set (9) having an outer rotor (43) with an outer peripheral surface (radially facing the peripheral surface (6) of the chamber (5) ( 8) has
characterized,
that a roller bearing (90) or a slide bearing element (90) for the radial mounting of the outer rotor (43) in the chamber (5) is arranged between the radially opposite circumferential surfaces (6, 8) of the chamber (5) and the outer rotor (43) . Gerotor pump according to claim 1,
characterized,
that the roller bearing (90) is a ball bearing, roller bearing or needle bearing. Gerotor pump according to claim 1,
characterized,
that it is in the plain bearing element (90) is an annularly closed, or composed of bearing shells bearing bush. Gerotor pump according to claim 1,
characterized,
that the slide bearing element (90) is a slide film. Gerotor pump according to claim 1,
characterized,
that the sliding bearing element (90) is a sliding material layer adhered to the chamber peripheral surface (6) or to the outer rotor peripheral surface (8). Gerotor pump according to claim 1, 3, 4 or 5,
characterized,
that the plain bearing element (90) is formed from carbon fiber material and / or from a plastic or / and from a ceramic material. Gerotor pump according to one of the preceding claims,
characterized,
that at least the part of the pump housing (3, 29) forming the peripheral chamber surface (6) and the gerotor barrel set (9) are made of stainless steel. Gerotor pump for liquid media with a pump housing (3, 29), a cylindrical chamber (5) in the pump housing (3, 29), a gerotor rotor set (9) accommodated in the cylindrical chamber (5) and which is to be driven in rotation by a pump drive shaft (11) in order to draw the liquid to be pumped from a suction connection (31) of the pump into a suction region of the chamber (5) and to expel the suctioned pump liquid from an ejection region of the chamber (5) to a pressure connection (33), the gerotor rotor set (9) having an outer rotor (43) with an outer peripheral surface (radially facing the peripheral surface (6) of the chamber (5) ( 8) has in particular according to one of claims 1 to 7,
characterized,
that in the cylindrical chamber (5) at least one thrust bearing in the form of a roller bearing or a sliding bearing element is provided for the axial bearing of the gerotor barrel (9). Gerotor pump according to claim 8,
characterized,
that a respective axial bearing in the form of a roller bearing or slide bearing element for the axial mounting of the gerotor barrel set (9) between the gerotor barrel set and the surfaces (65, 66) axially delimiting the chamber (5) on both end faces of the gerotor barrel set (9) of the pump housing (3, 29) is provided. Gerotor pump according to claim 8 or 9,
characterized,
that the axial bearing is a combined axial / radial bearing, in particular angular contact ball bearing.

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