WO1998026181A2

WO1998026181A2 - Gerotor pump for liquid media

Info

Publication number: WO1998026181A2
Application number: PCT/EP1997/006902
Authority: WO
Inventors: Ludwig Mokesch
Original assignee: Bavaria Pumpen Gmbh
Priority date: 1996-12-11
Filing date: 1997-12-10
Publication date: 1998-06-18
Also published as: WO1998026181A3; EP0956451A2; AU5561098A

Abstract

The invention relates to a gerotor pump for aqueous viscous media which has preferably a two-piece pump housing consisting of pump chamber housing (3) and connection cover (29), and has, in the pump chamber housing, a pump chamber in the form of a circular cylindrical cavity (5) with a gerotor running carriage (9) accommodated therein. The gerotor running carriage (9) is rotationally driven by the motor shaft (11) of a driving motor (13) which is mounted immediately on the pump housing. The motor shaft (11) is encircled in the pump chamber housing (3) by a groove (68) which is directly connected to a cavity (70) in the suction area of the pump chamber (5), so as to be able to introduce leakage liquid via the groove (68) into the suction area of the chamber (5). In the connection cover (29) there is a channel (49) connecting the suction side with the delivery side, with a valve inside which, depending on the pressure on the delivery side, diverts excess carrying capacity to the suction side. The valve can alternatively be designed as a carrying capacity control valve.

Description

Gerotor pump for liquid media

description

The invention relates to a gerotor pump with a pump housing, a cylindrical chamber in the pump housing, a gerotor barrel set accommodated in the cylindrical chamber and which is to be driven in rotation by a pump drive shaft in order to pump the liquid to be pumped from a suction connection of the pump into a suction area of the chamber aspirate and expel the aspirated pump liquid from an ejection region of the chamber to a pressure connection of the pump, the pump drive shaft coupled to the gerotor drive unit for driving it extending from a drive side of the pump through a bore in the housing into the cylindrical chamber, and wherein the pump has a shaft seal surrounding the pump drive shaft, which seals the pump against leakage of leakage liquid to the drive side.

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

The gerotor liquid pumps have a gerotor pump set, which consists of a ring rotor or outer rotor with internal teeth, which is rotatably mounted in the cylindrical chamber with little radial play to the periphery of the chamber, and an inner rotor with external teeth, which is driven by the pump drive shaft, the number of teeth of the inner rotor is 1 smaller than the number of teeth of 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 is only at a certain angle. richly meshing in the circumferential direction of the chamber engages in the toothing of the outer rotor in order to drive the gerotor rotor set for rotation. As soon as two adjacent teeth of the inner rotor are moved out of this angular region of the meshing engagement in the direction of rotation, an intermediate space is created between these teeth and two adjacent teeth of the outer rotor, which gap increases with further rotation over a suction angle region of the chamber, the teeth of the inner rotor being the teeth of the Run ahead of the outer rotor. After the intermediate space has reached a maximum volume, it becomes smaller again with further rotation over an ejection angle range of the chamber, until the teeth of the inner rotor again come into the angular range of the meshing engagement of the outer rotor. The suction angle area of the chamber is connected to a suction connection via a suction slot in a connection cover which closes the end of the chamber on the side opposite the drive side of the pump. The discharge angle range of the chamber is connected via a discharge slot in the connection cover to a pressure connection, so that a flow is generated from the suction connection to the pressure connection of the pump when the gerotor barrel is rotated.

In the previously known gerotor liquid pumps, the housing consists of at least three housing blocks, namely the connection cover, an eccentric ring receiving the gerotor barrel set and a bearing cover on the drive side of the pump, through which the drive shaft is guided, the drive shaft being outside the housing a shaft coupling is coupled to the shaft of a motor driving the pump.

So far, gerotor pumps have been used almost exclusively for pumping mineral oil or similar viscous media, since thinner pump media, especially at high pump pressures, cause sealing problems. Attempts have also already been made to design and use Gerotαr liquid pumps as water pumps. In order to achieve good pump running properties and to master the sealing problems, however, measures have hitherto been necessary which necessitated a comparatively complicated construction of the pump, a high manufacturing expenditure and a comparatively large number of individual parts.

The invention has for its object to provide a gerotor liquid pump of the type mentioned, which can be used as a pump for water or similar low-viscosity media, has a simple and compact structure and yet has a high pumping capacity.

From a first point of view, it is proposed to achieve this object that the wall surface of the housing which delimits the cylindrical chamber towards the drive side of the pump has a depression which extends along the suction region in the circumferential direction of the chamber and which has a groove in the circumferential surface which surrounds the shaft is connected to the bore in order to be able to discharge leakage liquid located between the bore and the shaft via the groove into the suction area of the chamber.

This construction, which can be realized with simple means and with little manufacturing effort, has the effect that the inevitable leakage fluid, which is present in particular in the case of thin media with high pressure between the circumference of the shaft and the circumference of the bore, is returned to the suction region of the chamber in an extremely efficient manner and thus the case drain pressure is effectively reduced. Since the groove lies in an area between the chamber and the shaft seal, the case drain pressure on the shaft seal is almost completely reduced, so that a commercially available shaft seal, such as a sealing ring, can be used. The measure according to the invention for reducing the case drain pressure does not require any drainage channels within the shaft, which also benefits the efforts to simplify construction.

The depression preferably extends in the shape of an arc in the circumferential direction of the shaft, wherein it is in direct connection with the groove essentially over its entire arc length.

Excellent running properties without any appreciable impairment of the pump performance are achieved if the gerotor rotor set has a certain axial play and a certain radial play with the adjacent running surfaces of the chamber. The radial play between the outer circumference of the gerotor barrel and the circumferential surface of the chamber is between 0.025 and 0.06 mm in a preferred embodiment. In this embodiment, the axial play between the gerotor barrel set and the respectively opposite end face of the chamber is between 0.02 and 0.035 mm.

According to a particularly preferred embodiment of the invention, on the side opposite the drive side, the pump has a connection cover delimiting the cylindrical chamber on the end face with the suction connection and the pressure connection provided thereon, the connection cover having a suction slot connected to the suction connection and the suction region of the chamber. and has an ejection slot in its surface delimiting the chamber, which is connected to the pressure connection and the ejection region of the chamber, and a channel connecting the suction slot to the ejection slot is provided in the connection cover, in which a valve which is to be opened toward the suction slot is arranged.

This valve can be a spring-loaded pressure relief valve which opens the channel when a certain maximum opening pressure is reached in the area of the pressure connection and the discharge slot opens against the force of the valve spring. The valve Lst is designed for a certain working pressure and for a certain maximum pressure, which can be up to 60-70 bar in the pump according to the invention. If this maximum pressure is exceeded on the consumer side, the pressure limiting valve ensures that the excess amount is drained off to the suction side and thus forms a reliable overpressure protection integrated in the housing.

According to a particularly preferred embodiment, a desired performance characteristic can be maintained in accordance with the characteristic of the valve spring and the valve construction, in that the valve opens at certain pressures on the pressure side only to such an extent that excess delivery volume reaches the suction side via the channel and the pump otherwise the at the relevant pressure on the pressure side promotes the desired delivery rate according to the desired performance characteristics via the pressure connection to the "consumer". If necessary, the spring can be exchanged for a spring with a different characteristic.

According to a further variant, the valve has an adjusting mechanism which optionally prestresses the valve spring to a greater or lesser extent and which can be actuated from outside when the valve is installed.

In an alternative embodiment, the valve is an adjustable flow control valve, which opens the channel more or less depending on the valve position set in order to divert part of the liquid discharged from the discharge area of the chamber and return it to the suction area.

Although various features of the invention can be successfully implemented in a three-part or multi-part pump housing, in a further particularly preferred embodiment of the invention the pump housing is constructed in two parts, it consisting of a pump chamber housing block and a connection cover and the cylindrical chamber is formed as a recess in the pump chamber housing block, which is covered on the front side of the pump chamber housing block facing away from the drive side of the pump by the connection cover. As a result, the effort to simplify construction and to reduce manufacturing costs is met to an even greater extent. The above-mentioned aspect of the two-part design of the pump housing may have independent significance in the context of the invention.

Another extremely advantageous measure is that the pump housing on the drive side of the pump is connected directly to the housing of a drive motor, in particular an electric motor, the motor shaft of which forms the pump drive shaft. This aspect may also have independent significance in the context of the invention. Not only is there an extremely compact and space-saving unit made up of a pump and pump drive, but there are also significant simplifications with regard to the centering of the shaft while ensuring excellent running properties of the pump. Since the motor shaft engages directly in the gerotor barrel, no intermediate shaft coupling is required. Furthermore, it is not necessary to additionally provide a roller bearing arrangement or another complex bearing for the drive shaft, which is already mounted in the motor housing, in the pump. The pump housing and the motor housing are preferably connected to one another by common screw arrangements, which already ensure that the motor housing and the pump housing are fixed in the correct position.

The gerotor liquid pump according to the invention can be operated at engine speeds between 50 and 6000 rpm, depending on the desired pump output. It is suitable for pumping low-viscosity media such as water, beverages, fuels, HFA hydraulic fluid and the like, although it is not excluded that it can also be used oil pump can be used. It can therefore be used both in the industrial sector and in the private household sector.

If the pump is to be used in the food sector, for example in beverage metering, care must be taken to use food-safe materials for the pump components that come into contact with the pump medium. In a preferred embodiment, the pump housing consists of a brass material, in particular special brass or possibly bronze, and the gerotor barrel set consists of a stainless steel.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the figures.

Fig. 1 a shows a first embodiment of the invention in one

Longitudinal section.

Fig. 1 b shows a connection cover of the gerotor liquid pump

1 a in a disassembled state in a plan view (from FIG. 1 a from the left) of an end face to be connected to a pump chamber housing, an area being shown broken away.

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

FIG. 1 d shows a view of the pump chamber housing corresponding to FIG. 1 c, but the gerotor running set has been removed.

2a and 2b show a second embodiment in a representation corresponding to FIGS. 1 a and 1 b. 3a and 3b show a third embodiment in a representation corresponding to FIGS. 1 a and 1 b.

1 a shows a preferred exemplary embodiment of the invention in a longitudinal section.

The gerotor pump 1 has a pump chamber housing 3 with a circular cylindrical recess 5 on the connection face 7 of the pump chamber housing 3. The circular cylindrical recess 5 forms a chamber in which a gerotor running set 9, which is yet to be explained, is received, which is driven by a drive shaft 1 1 of a drive motor 1 3 is driven in rotation. The drive motor 1 3 is arranged with its housing 1 5 directly on the end side 1 7 of the pump chamber housing 3 opposite the connection end face 7. The shaft 1 1 extends through the bore 1 9 into the chamber 5 of the pump chamber housing 3. On the front side 1 7 of the pump chamber housing 3, the annular gap 21 between the shaft 1 1 and the circumference of the bore 1 9 through a shaft sealing ring 23 to the motor 1 3 sealed.

In the chamber 5 there is an inner ring or inner rotor 25 of the gerotor barrel 9 via a coupling 27, e.g. a feather key or the like., coupled for common rotation with the shaft 1 1, wherein the inner ring 25 is arranged coaxially to the shaft 1 1 on the pump-side end portion of the shaft 1 1. The gerotor rotor 9 is held axially movable within its axial play on the shaft 1 1.

On the connection face 7 of the pump chamber housing 3 there is a connection cover 29 which extends over the recess 5 and which has a suction connection 31 and a pressure connection 33. The suction connection 31 is connected to a suction region 37 of the chamber 5 via a suction kidney 35 designed as a ring segment-like recess in the connection cover 29, whereas the pressure connection 33 is connected an ejection kidney 39 designed as a ring segment-like recess in the connection cover 29 is connected to an ejection region 41 of the chamber 5.

From Fig. 1 b it can be seen that the suction kidney 35 of the exhaust kidney 39 is diametrically opposite.

For an explanation of the structure and function of the gerotor pump running set 9, reference is made below to FIG. 1 c. Fig. 1 c shows in a (not to scale) top view of the connection end face 7 of the pump chamber housing 3, the inner rotor 25 provided with an external toothing and driven by the shaft 11 within an outer rotor 43 formed with an internal toothing. The outer rotor 43 is in the cylindrical chamber 5 is rotatably mounted substantially coaxially to the chamber 5, the common axis of the chamber 5 and the outer rotor 43 being offset parallel to the common axis of the shaft 11 and the inner rotor 25. It should also be pointed out that the inner toothing of the outer rotor 43 has one tooth more than the outer toothing of the inner rotor 25 arranged eccentrically to the outer rotor 43. The position of the suction kidney 35 provided in the connecting cover 29 and the position of the exhaust kidney 39 provided in the connecting cover 29 are approximate indicated at 35 and 39 in projection.

When the inner rotor 25 rotates, the mutual engagement of the toothings of the inner rotor 25 and the outer rotor 43 causes the outer rotor 43 to rotate as well. As can be seen from the snapshot according to FIG. 1 c, the toothings of the elements 25 and 43 only engage over a certain one Angular range - in Fig. 1 c on the left side - completely in one another, whereas in a diametrically opposite angular range - in Fig. 1 c on the right side - the teeth of the inner rotor 25 and the teeth of the outer rotor 43 do not mesh with each other. During the rotation of the gerotor barrel 9 it happens that the teeth of the Inner rotor 25 overtake the teeth of outer rotor 43 in the latter angular range in the direction of rotation. When unscrewing from the first-mentioned angular range of engagement of the toothings, an intermediate space 45a or 45b or 45c, which moves with increasing rotation and which increases with increasing rotation, is formed between two adjacent teeth of the inner rotor 25 and two adjacent teeth of the outer rotor 43, which then approaches the former Angular range of engagement of the teeth becomes smaller again and finally disappears. During the phase of the enlargement of the space in question, it runs past the suction kidney 35, so that liquid supplied to the suction connection 31 is sucked into the space 45 in question. During the phase of the reduction of the relevant space 45, this runs past the discharge kidney 39, so that the liquid is pressed over the discharge kidney 39 to the pressure connection 33. In this way, continuous pump operation can be realized by rotating shaft 11.

According to the invention it is achieved with simple means that a desired performance characteristic can be set and maintained. For this purpose, a spring-loaded pressure relief valve or pressure relief valve 47 is provided in a channel 49, which is formed in the connection cover 29 and connects the suction connection 31 or the suction kidney 35 with the pressure connection 33 or the discharge kidney 39. The valve body 51 of the pressure relief valve 47 can open against the force of the spring 53 to the suction side (suction kidney 35), 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 the suction side (at 35). According to the characteristic curve of the spring 53 and the valve construction, a desired performance characteristic can be maintained in that the valve opens at certain pressures on the pressure side only to such an extent that excess delivery volume reaches the suction side via the channel 49 and the pump otherwise the in which relevant pressure on the pressure side promotes the desired flow rate according to the desired performance characteristics via the pressure connection to the "consumer". If necessary, the spring 53 can be exchanged for a spring with a different characteristic. In addition, the valve 47 has the function of overpressure protection. When a predetermined maximum pressure is reached, the valve opens to maximum passage, so that the channel 49 forms the main flow path and circulates the pump from the pressure side to the suction side.

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

If one wishes to dispense with the particularly advantageous function of maintaining a desired performance characteristic, the valve 47 can alternatively be designed in such a way that it only fulfills the function of overpressure protection.

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 plug 57 which is screwed into a threaded bore 59 of the connection cover 29.

At 61 a valve tappet connected to the valve body 51 is shown in FIG. 1 a, which is guided with its end remote from the valve body 51 in a bore 63 of the screw plug 57.

A particular advantage of the gerotor pump 1 according to the invention is that despite its simple and compact construction for pumping water or similar thin media, it can be used at pump pressures up to 60-70 bar and pump speeds up to 6000 rpm. The pump 1 according to the invention also has a permanent high performance excellent running properties and a long service life and is also easy to maintain.

Investigations have shown that the running properties of the gerotor pump 1 according to the invention can be optimized when used as a pump for water or aqueous-viscous media if a slight radial play is permitted between the circumference of the outer rotor 43 and the circumference of the cylindrical chamber 5 , this play should preferably be 0.03-0.05 mm. In addition, there is an axial play between the tread 65 of the pump chamber housing 3 and the gerotor rotor set 9 of approximately 0.025 mm and also an axial play of approximately 0.025-0.03 mm between the tread 66 of the connection cover 29 and the gerotor rotor set 9. Due to these games, the pumping medium has a self-lubricating effect, without the pumping performance being significantly impaired.

The problem of sealing the pump chamber housing 3 to the side of the drive motor 1 3 to be observed under the above-mentioned conditions has been solved in the pump 1 according to the invention with very simple means using commercially available shaft seals 23.

As shown in FIGS. 1 a and 1 d, an annular groove 68 is provided in the pump chamber housing 3 at a small axial distance from the chamber 5, which surrounds the motor shaft 11. This annular groove 68 is connected to a depression 70 in the bottom of the chamber 5, the depression 70 running in the angular region of the chamber 5 which forms the suction region and over which the suction kidney 35 also extends. The depression 70 preferably has a kidney shape corresponding to the suction kidney 35 and, viewed axially, lies in alignment with the suction kidney 35. This simple construction has the effect that the pressure (approximate operating pressure) occurring via leakage fluid in the small annular gap 72 (gap size, for example 0.2-0.4 mm) between the drive shaft 11 and the bore 19 via the annular groove 68 and the kidney-shaped recess 70 to the suction side of the chamber 5 is reduced to such an extent that in the area between the annular groove 68 and the commercially available shaft sealing ring 23 there is only a small residual liquid pressure, for example 0-0.1 bar, which is present from the sealing ring 23 can be safely accommodated without any sealing problems, especially since commercially available shaft seals are available for pressures of 0.5 - 30 bar.

In the embodiment according to FIGS. 1 a - 1 d it should be emphasized that it is not necessary to implement the leakage fluid pressure to provide leakage fluid channels in the drive shaft 1 1, so that there is also a contribution to simplifying the pump structure without impairing the efficiency is.

To the excellent running properties of the gerotor pump 1 also contributes that the drive motor 1 3 is arranged directly on the housing block 3 and drives the gerotor running set 9 with its comparatively short motor shaft 1 1. The use of the motor shaft 1 1 directly as a pump shaft avoids the previously usual shaft couplings between the pump shaft and the separate motor shaft. In the gerotor pump 1 according to the invention, the drive shaft 11 can be centered in a simple manner while avoiding expensive shaft bearings within the pump housing 3, so that low-wear operation is ensured. The direct attachment of the housing of the drive motor 1 3 to the pump housing 3, 29 also leads to the fact that overall a compact, space-saving unit consisting of pump and drive is obtained, the above-mentioned measures for reducing the leakage fluid pressure reliably ensuring that the low-viscosity pump medium is not can penetrate into the motor housing. The relative orientation and centering of the motor 1 3, the pump chamber housing 3 and the connecting cover 29 to one another and the common fastening of these elements to one another is carried out by the screw arrangements 74 which enforce the elements 13, 3 and 29 in the axial direction and fix them to one another 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 are combined to form an integral housing unit.

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

2a and 2b show a second embodiment of a gerotor pump 1 according to the invention in a view corresponding to FIGS. 1 a and 1 b. Elements in FIGS. 2a and 2b which correspond to elements of the pump according to FIGS. 1a-1d are identified with the same reference numerals, so that reference can be made to the description of the first exemplary embodiment.

The second exemplary embodiment differs from the first exemplary embodiment in that the structure of the valve 47 is changed. In the valve 47 shown in FIGS. 2a and 2b, the biasing force of the valve spring 53 can be adjusted without removing the valve 47 in order to adjust the working pressure (performance characteristics) or permissible maximum pressure of pump 1. For this purpose, an adjusting screw 77 passing through the locking screw 57 is provided, on which the axially displaceable guide cylinder 78 of the valve tappet 61 is supported at its end remote from the valve spring 53. If the adjusting screw 77 is now screwed further towards the valve body or valve cone 51, the valve spring 53 supported on the guide cylinder 78 is further compressed and thus increases its biasing force on the valve body 51. The valve body 51 will then lift off its seat at a correspondingly increased pressure on the pressure side of the pump 1 in order to discharge an excess amount of pump liquid to the suction side via the channel 49.

3a and 3b show a third embodiment of a gerotor pump 1 according to the invention, which differs from the first two embodiments by the type of valve 47a.

The valve 47a is not designed as a spring-loaded pressure relief valve as in the two previous exemplary embodiments, but rather as an adjustable quantity control valve. The valve body (valve cone) 51 a can be shifted into a position raised from the valve seat 80 by adjusting the adjusting screw 77 a of the adjusting spindle 78 a, in order to be able to variably adjust the gap between valve body 51 a and valve seat 80 and thus the opening width of the valve. In this way, at a given pressure at the pressure connection 33, a delivery quantity dependent on the setting of the valve can be derived via the channel 49 to the suction side. This changes the maximum delivery rate of the pump at the given pressure. The valve 47a of the third exemplary embodiment of the invention therefore serves to set a respective maximum delivery rate of the pump.

Claims

Expectations

. Gerotor pump for liquid media with a pump housing (3, 29), a cylindrical chamber (5) in the pump housing (3, 29), a gerotor rotor (9) accommodated in the cylindrical chamber (5), which is driven by a pump drive shaft (1 1) is to be driven in rotation in order to draw in the liquid to be pumped from a suction connection (31) of the pump into a suction area of the chamber (5) and to drive out the pumped liquid from a discharge area of the chamber (5) to a pressure connection (33), the pump drive shaft (1 1) coupled to the gerotor running set (9) for driving it extends from a drive side of the pump through a bore (1 9) of the housing (3, 29) into the cylindrical chamber (5), and being the

Pump has a shaft seal (23) surrounding the pump drive shaft (1 1), which seals the pump against leakage of leakage fluid to the drive side, characterized in that the wall surface (65) of the cylindrical chamber (5) which delimits the end to the drive side of the pump Housing (3, 29) has a depression (70) which extends along the suction region in the circumferential direction of the chamber (5) and which has a groove (68) in the circumferential surface of the bore (1 9) surrounding the shaft (1 1) Connection is established between the bore (1 9) and the

Leakage liquid (1 1) located through the groove (68) in the suction area of the chamber (5).

2. Gerotor pump according to claim 1, characterized in that the recess (70) - seen in the axial direction of the chamber (5) - extends arcuately in the circumferential direction of the shaft (1 1) and the depression (70) communicates directly with the groove (68) over substantially its entire arc length.

3. Gerotor pump according to claim 1 or 2, characterized in that the gerotor rotor set has a certain axial play and a certain radial play to the adjacent running surfaces of the chamber (5).

4. Gerotor pump according to claim 3, characterized in that the radial clearance between the outer circumference of the gerotor barrel (9) and the peripheral surface of the chamber (5) is between 0.025 and 0.06 mm and that the axial clearance between the gerotor barrel (9) and the opposite, frontal

Boundary surface of the chamber (5) is between 0.02 and 0.035 mm.

5. Gerotor pump for liquid media with a pump housing (3, 29), a cylindrical chamber (5) in the pump housing (3, 29), in the cylindrical chamber (5) accommodated gerotor rotor set (9) by a pump drive shaft (1 1) is to be driven in a rotating manner in order to draw the liquid to be pumped from a suction connection (31) of the pump into a suction area of the chamber (5) and to draw the pumped liquid from a discharge area of the chamber (5) to a pressure connection (33 ) to drive out, the pump drive shaft (1 1) coupled to the gerotor running set (9) to drive it from a drive side of the pump through a bore (1 9) of the housing (3, 29) into the cylindrical chamber ( 5), and wherein the pump has a shaft surrounding the pump drive shaft (1 1) Seal (23), which seals the pump against leakage of leakage liquid to the drive side, in particular according to one of the preceding claims, characterized in that the pump on the side opposite the drive side has a connection cover (29) which delimits the cylindrical chamber (5) on the end face. with the suction connection (31) and the pressure connection (33) provided thereon, the connection cover (29) having a suction slot (35) connected to the suction connection (31) and the suction region of the chamber (5) - and one to the pressure connection (33) and the ejection area of the chamber (5) in connection with the ejection slot (39) in its area (7) delimiting the chamber (5) and in the connection cover (29) the suction slot (35) with the ejection slot (39) connecting channel (49) is provided, in which a to

Suction slot (35) to open valve (47) is arranged.

6. Gerotor pump according to claim 5, characterized in that the valve (47) is a spring-loaded valve, which in

Depending on the pressure in the area of the pressure connection (33), an excess flow rate is discharged through the channel (49) to the suction slot (35) in order to maintain a desired performance characteristic.

7. Gerotor pump according to claim 5, characterized in that the valve (47) is a spring-loaded pressure relief valve which counteracts the channel (49) when a certain maximum opening pressure is reached in the region of the pressure connection (33) and the discharge slot (39) the force of the valve spring (53) opens.

8. Gerotor pump according to claim 6 or 7, characterized in that the valve spring (53) against a valve spring with a different spring characteristic is operationally interchangeable to change the opening pressure of the pressure relief valve (47).

9. Gerotor pump according to claim 6, 7 or 8, characterized in that the valve (47) has a valve spring (53) optionally more or less prestressing adjusting mechanism (77, 82) which can be actuated from the outside when the valve (47) is installed is.

10. Gerotor pump according to claim 5, characterized in that the valve is an adjustable flow control valve (47a) which opens the channel (49) more or less depending on the set valve position to a part of the ejected from the discharge region of the chamber (5) To branch off the liquid flow rate and return it to the suction area.

1 1. Gerotor pump for liquid media with a pump housing (3, 29), a cylindrical chamber (5) in the pump housing (3, 29), a gerotor rotor (9) accommodated in the cylindrical chamber (5), which is driven by a pump drive shaft (1 1) is to be driven in rotation in order to draw in the liquid to be pumped from a suction connection (31) of the pump into a suction area of the chamber (5) and to drive out the pumped liquid from a discharge area of the chamber (5) to a pressure connection (33), which with the gerotor barrel (9) to the

Drive-coupled pump drive shaft (1 1) from a drive side of the pump through a bore (1 9) in the housing (3, 29) extends into the cylindrical chamber (5), and wherein the pump has a shaft seal (23) surrounding the pump drive shaft (1 1), which seals the pump against leakage of leakage liquid to the drive side, in particular according to one of the preceding claims, characterized in that that the pump housing (3, 29) is formed in two parts and consists of a pump chamber housing block (3) and a connection cover (29), the cylindrical chamber (5) being formed as a depression in the pump chamber housing block (3), which on the

The drive side of the pump facing away from the pump chamber housing block (3) is covered on the front side by the connection cover (29).

2. 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) by a pump drive shaft (1 1) is to be driven in rotation in order to draw the liquid to be pumped from a suction connection (31) of the pump into a suction area of the chamber (5) and the pumped liquid from a discharge area of the chamber (5) to a pressure connection (33) drive out, the pump drive shaft (1 1) coupled to the gerotor running set (9) for driving it from a drive side of the pump through a bore (1 9) of the housing (3, 29) into the cylindrical chamber (5) extends, and wherein the pump has a shaft seal (23) surrounding the pump drive shaft (11), which seals the pump against leakage of leakage to the drive side, in particular according to one of the preceding claims, characterized, that the pump housing (3, 29) on the drive side of the pump is directly connected to the housing (15) of a drive motor, in particular an electric motor (13), the motor shaft of which forms the pump drive shaft (11).