WO2021005155A1

WO2021005155A1 - Gearwheel pump

Info

Publication number: WO2021005155A1
Application number: PCT/EP2020/069364
Authority: WO
Inventors: Heinz Leiber
Original assignee: Ipgate Ag
Priority date: 2019-07-10
Filing date: 2020-07-09
Publication date: 2021-01-14
Also published as: DE112020003261A5; DE102019118697A1

Abstract

A gearwheel pump (Z) in the form of an internal gearwheel pump or a toothed-ring pump or gerotor pump, having an inner gearwheel (2), which is driven by a drive shaft (1), and having an internally toothed ring (3), wherein the axis (2a) of the inner gearwheel (2) is arranged coaxially with respect to the axis (3a) of the internally toothed ring (3). The inner gearwheel (2) and the internally toothed ring (3) are arranged in an axial direction between two housing parts (7.1, 7.1b, 7.2), wherein the housing parts (7.1, 7.1b, 7.2) are cohesively connected to one another directly or via at least one interposed part (4), in particular in the form of a ring. Alternatively, the housing parts (7.1, 7.1a, 7.2) are pressed against one another by means of at least one elastic and/or resilient part (41).

Description

Gear pump

State of the art

Gear pumps or gerotor pumps are widely used for medium to high flow rates. In the pressure range, the gear pump is limited due to the large number of gap seals; in some cases, multi-stage pumps are used in which the pressure load per pump is lower. Gear pumps are mostly used for applications with a pressure of up to 300 bar.

Gear pumps are mostly driven by electric motors. It is widespread here to provide a series connection, i.e. to design the electric motor and pump separately, using a common drive shaft, as disclosed in DE 102017106927 A with a coupling. This requires a lot of installation space, which is particularly disadvantageous when used in a unit with limited space, such as an integrated braking system or a transmission control. Furthermore, in this arrangement, the motor axis is rigidly connected to the pump shaft without a coupling, which results in extremely small tolerances or tension in the bearing. Furthermore, the pump in the pump housing is gela with many parts that require small tolerances in order to keep the leakage-relevant column small.

DE 2015017074 shows a pump with a separate drive shaft for the pump and just as many parts, the tolerances of which are small and thus manufacturing costs are high. To reduce the axial gaps, pressure compensation plates are also provided here.

DE 102012212686 also shows a separate drive shaft for the pump with sliding bearings. Here, too, determine the axial play of 4 parts, the tolerances of which must be matched to one another, usually by pairing the parts together.

From WO 01/42069 a small motor-pump unit is known in which the pump is essentially arranged within the rotor or the rotor. In this arrangement, however, the size of the pump is limited to the rotor size and the motor mounting and the arrangement of the motor angle sensor is complex.

From DE 4113373 a fuel pump for low pressure levels less than 10 bar is known, with mounting of the pump in a kind of flange, but without a connection to a hydraulic block with control valves. In addition, the suction and pressure connections are not located together in the bearing flange. The medium to be pumped flows around the motor, which prevents the pump from being used as a high-pressure pump.

The construction of a gear pump is made more difficult and complex if it is to act on two hydraulic circuits, as in WO

2012/103925, DE 102014212538 and DE 102014117189.

As mentioned above, the pressure range and efficiency depend on the number of sealing surfaces to be sealed, which are dependent on the play between the teeth of the interlocking gears and the play or distance between the inner wall of the housing and the tooth tips leading along it. It also depends on the tightness between tween the gears and the axially adjacent housing walls. The larger the axial gap between the housing and the gear, the lower the performance and the maximum possible pressure that can be achieved. The storage of the rotating parts also incurs significant costs. This is problematic, for example, when the motor and pump are formed separately.

The object of the present invention is to further develop a gear pump in such a way that it is less complex.

This object is achieved according to the invention with a gear pump having the features of claim 1. Advantageous configurations of these gear pumps result from the features of the subclaims.

The gear pumps according to the invention are advantageously characterized by a few parts with small necessary tolerances. In addition, the gear pump according to the invention can be made as a, in particular closed, structural unit and can be easily and easily integrated or built into a wide variety of units.

By appropriately designing the mounting of the inner gear, in particular on the drive shaft, the inner ring gear and the possibly necessary outer ring, only a few dimensions with small tolerances have to be provided. Optimally, only one tolerance has to be taken into account. The aforementioned parts preferably form a structural unit which can be installed in a housing or a recess in a housing part. In addition, the remaining parts such as the inner gear, the inner ring gear and, if required, the sickle must be designed in such a way that they can be produced very inexpensively with small tolerances using flat grinding or, for example, cold extrusion.

Furthermore, by means of a corresponding design, it is possible for the outer ring to be welded to the outer disks or the outer disk to a pot-shaped part which receives the inner gear and the inner ring gear. A material connection can be dispensed with if the elements of the gear pump are compressed in the axial direction by means of an elastic part, such as a ring made of elastic material or a spring. Here, corresponding Exercise appropriate forces so that the gear pump is correspondingly tight at the pressures to be generated.

For this it is necessary that the inner wheel is driven with a wedge or pin via the drive shaft. The gear pump is preferably used to support the drive shaft. The drive shaft can be supported entirely or only partially by the gear pump.

Furthermore, the gear pump can be arranged or mounted within the drive housing in its bearing flange or a separate housing.

The drive housing with the gear pump arranged therein can be attached to a hydraulic block with additional hydraulic components, such as valves, and to an electronics housing or directly to the electronics housing without a hydraulic block. This means that the electrical connections between the electronics housing and the drive or the gear pump, in particular for the stator winding and the motor sensor, are easy to make.

The gear pump can be designed as a 1-stage as well as a multi-stage, in particular two-stage, gear pump. A two-stage gear pump can be formed by a series connection of two single-stage gear pumps. A compact unit with a small installation volume is thus possible.

The gear pump can either be an internal gear pump or a toothed ring pump, which is also called a gerator pump.

Various possible embodiments are conceivable. Some possible embodiments are briefly described below. However, this list is not exhaustive. All embodiments have in common that the gear pump has an internal gear driven via a drive shaft and an internal gear, the axis of the internal gear being arranged coaxially to the axis of the internal gear, and that in the axial direction at least on one side next to the internal gear and the interior Toothed ring an outer disc is arranged.

In a first possible embodiment, the gear pump is designed as an internal gear pump or as a gerotor pump, the internal gear rim being encompassed by an outer part, e.g. in the form of a ring, the at least one outer disk being materially connected to the outer part.

In a second possible embodiment, the gear pump is designed as a toothed ring pump, with the at least one outer disk being firmly connected to the internal gear rim.

In the context of the invention, an integral connection is understood to mean a welded, soldered or adhesive connection.

In a further possible embodiment of the gear pump according to the invention in the form of an internal gear pump or gerotor pump, the se has an internal gear driven via a drive shaft and an internal gear rim, with an outer disc being arranged in the axial direction at least on one side next to the internal gear wheel and the internal gear rim is. When the gear pump is installed, at least one elastic and / or resilient part, in particular in the form of a ring made of elastic material, generates a force in the axial direction on an outer disk and / or a cup-shaped part that accommodates the inner gear and the inner ring gear. The part can lie in a circular groove of an outer disk and / or a groove of the cup-shaped part arranged in the flat outer side and be supported on a side surface of an adjacent part, such as the housing of a hydraulic block.

For all of the aforementioned embodiments, the outer part is a sleeve, a cup-shaped part, a bearing, in particular in the form of a roller or ball bearing, or a wall, in particular a housing flange with a recess.

Particularly preferably, the drive shaft, the inner gear, the inner ring gear, as well as the two outer disks or the one outer disk and the cup-shaped part a composite or a structural unit. If the Zahnradpum pe also has an outer ring and / or a radial bearing for the inner ring gear, these parts also belong to the unit or the module.

In order to realize a cohesive connection of two parts with one another without interfering with the installation or assembly of the gear pump, chamfers and / or recesses are advantageously provided in the radial outer wall of the corresponding parts. The turfs or recesses of the parts to be connected must correspond to one another, i.e. to be provided on the opposite edges of the parts. In particular, these can be designed to run around. Gear pump according to one of the preceding claims, characterized in that the internal gear (2) is arranged tiltable to the drive shaft (1), in particular is coupled to the drive shaft (1) by means of an elastic and / or flexible connection.

The inner gear can preferably be mounted in a tiltable manner relative to the drive shaft, so that tolerances and play between the drive shaft and the inner gear or the inner ring gear can be compensated for. A part made of elastic and / or flexible material can also be arranged between the toothed wheel and the drive shaft to compensate for tolerances and play.

Description of the figures

Various possible embodiments of the invention are explained in more detail below with reference to drawings.

Show it :

Fig. 1: a first possible embodiment of a gear pump of a pressure supply device according to the invention, wherein the gear pump is designed as a 1-stage gear pump, and the drive shaft is supported, inter alia, via the inner gear of the gear pump;

FIG. La: a section through the internal gear pump according to FIG. 1; FIG. 1b: a section through the area of the gear pump according to FIG. 1, in which the fixed outer parts of the gear pump are welded together;

Fig. Lc: a slightly modified embodiment of the gear pump ge compared to the embodiment shown in Figure la with Schllitz ter sickle and its mounting via a bolt;

Fig. 2: an embodiment of the gear pump with a ball bearing between the inner ring gear and the outer ring, the drive shaft in the gear pump is also superimposed on the inner gear GE;

3: an embodiment in which the drive shaft is mounted in the gear pump by means of roller bearings;

Fig. 4: an engine mounting both in the drive housing and in the

Gear pump, wherein the first bearing is formed with magnetic Verspan voltage and the second bearing is arranged in the gear pump;

4a: an engine mounting with both bearings in the gear pump;

Fig. 5: a mounting device for a gear pump according to the invention pe.

Figures 1 and la show a possible embodiment of an internal gear pump with drive shaft 1, internal gear 2, internal ring gear 3, guide part in the form of a sickle 5, the latter being connected via the bolt 6 to the outer disks 7.1 and 7.2 and thus fixed. The aforementioned parts are embedded in the two outer disks 7.1 and 7.2 together with the outer ring 4, the outer ring 4 being connected to the two outer disks 7.1 and 7.2 by welding LS, which is shown enlarged in FIG. The two outer disks 7.1 and 7.2 together with the outer ring 4 form the pump housing ZG of the gear pump Z, which is mounted in the recess 18b of the wall 18. The wall 18 forms a flange on or with which the drive housing can be fastened to the hydraulic housing.

In Fig. Lb it is shown that the outer diameter of the areas 7.1a, 7.2a and 4a of the outer disks 7.1, 7.2 and the outer ring 4 provided for the welding LS is smaller than the largest outer diameter D _{A of} the parts so that they can be installed in the recess 18b, which can be formed by means of a bore, is not hindered by the weld LS. The Monta ge and adjustment of these parts is described in FIG.

The gap or play between the rotating inner gear 2 and the inner ring gear 3 to the gear pump housing ZG, which is formed by the outer disks 7.1 and 7.2 and above all by the outer ring 4, is decisive for the losses due to leakage flow. The disks 7.1, 7.2 and the outer ring 4 can be manufactured very precisely by flat grinding, so that small gaps or clearances are possible.

The inner gear 2 is guided on the drive shaft 1 through the short collar 11. This has the advantage that small angular tolerances between gear 2 and shaft 1 do not lead to gear 2 jamming in the housing ZG. The torque to gear 2 is transmitted via a driver 10. This torque is also transmitted by the locking bolt 9 to the wall application or the flange 18 transferred. At the front, both suction and pressure connections act with seals, which are connected to the hydraulic housing HCU.

The outer disk 7.2 is provided with a seal 14 to the hydraulic housing HCU. The shaft seals 13.1 and 13.2 also act. The drive shaft 1 also has a shaft journal 8, which is required for mounting the pump housing ZG, see FIG. 6. To reduce the friction due to the pressure forces on the inner ring gear 3, a roller bearing, needle or ball bearing 17a, see FIG. 2, can be installed between the latter and the outer ring 4.

Fig. La shows the gear pump Z in section. The so-called sickle 5, which is in one piece here, plays an important role in the sealing function with central bearing 6 is executed. Here act on the sickle 5, the pressure forces of the enclosed areas. The sickle 5 is here centrally mounted on a pin 6, as is known from the prior art. The connections for suction S and the pressure outlet with pressure P with direction of rotation are also shown in FIG. Of course, the direction of flow changes as soon as the gear 2 rotates in the other direction, whereby the suction side S becomes the pressure output P and vice versa.

As shown in Figure lc, it is also possible to design the sickle 5 th in two parts by a two-sided fixation 6a, 6b without a shaft with a compensating spring, which results in an even better sealing function. Here, the pressure equalization can be optimized through recesses on the sickle 5 and also axially to the outer disks 7.1 and 7.2.

Instead of the internal gear pump, a gerotor pump can also be used, which does not have a sickle and a fixed internal gear rim. The inner gear is mounted eccentrically on an eccentric being driven by the drive shaft and rolls in the stationary internal gear rim. A trochoidal tooth system is preferred as the tooth system. The leakage oil must be diverted to S via the leakage flow channel in order to relieve the seals.

FIG. 2 shows the same construction of the gear pump Z according to FIG. 1, with the difference being a sliding bearing 16 on both sides of the drive shaft 1 in the two outer disks 7.1 and 7.2. This eliminates the need for a separate engine mount, as shown in Figures 6 and 6a. The leakage oil channels 15 are modified here.

FIG. 3 also shows the similar structure of the pressure supply device according to FIGS. 1 and 2, with the difference in the use of roller bearings 17 to minimize bearing friction. In addition, the outer disk 7.1 and the outer ring 4 are replaced by the part 7.1b, which is pot-shaped and accommodates the inner gear 2 and the inner ring gear 3. In this design, only one weld LS is required, which connects the part 7.1b and the outer pane 7.2 materially. Fig. 4 shows a representation of the entire assembly consisting of Mo tor 22, pump Z, HCU and ECU, which is able to exercise pressure regulation and control for systems such as brakes, transmissions, etc. The main focus here is on the combination of motor and pump. The pump is arranged in the bearing flange 18, as shown in FIGS. 1 to 3, or attached to the HCU or ECU in a separate pump housing 40, as shown in the upper half of the figure. In Fig. 4 the simplest version according to Fig. 1 is shown, which requires an additional motor bearing 20 in which the shaft 1 is mounted. As usual, the motor consists of a rotor 21, which is connected to the shaft 1 via the driver 10a. The rotor 21 is axially preloaded by its magnetic force F via a permanent magnet 30a in the housing 30. This is a solution for the motor manufacturer who manufactures and tests the motor with housing 22 and stator and winding 23 and delivers it to the system supplier. Here the motor is tested without a pump with an auxiliary shaft. Thereafter, when the shaft is removed, the rotor is centered by the axial magnetic force F, so that the shaft 1 can then be assembled with the rotor during final assembly. The permanent magnet 30a can, with its force acting axially on the rotor 21, if it is large enough, compensate for tilting forces of the rotor, so that no further support of the rotor 21 in addition to the bearing 20 is necessary. A sufficiently large clearance can or should be provided in the gear pump.

The drive housing must also be joined and fastened here with the flange 18 at 25a - shown in the lower half of the figure, e.g. B. with springs, which are attached in segments over three connections who the. A housing seal 31 is also necessary here. It can be fastened by caulking, at 25 from the engine flange with HCU or ECU, see upper half of the figure 28. The pump version with pump housing is shown here. The motor is shown here as a brushless motor that needs a Mo torsensor for commutation and control of the volume delivery of the pump. This motor sensor is arranged at a distance from the drive housing 22, with a sensor shaft 26 which is net or attached to the drive shaft 1 and carries a sensor target 27. This target 27 acts on the sensor element 28, which is arranged on the circuit board of the ECU.

The winding is connected to the ECU via contact bars 24.

The motor with bearing flange 18 can be connected directly to the hydraulic housing HCU, which contains valves or other hydraulic components, with the pump. If this is not the case, a connection of the drive housing 22, 18 directly to the housing of the ECU is possible.

It is also possible to assign the gear pump Z in a pump housing 40 which is connected directly to the hydraulic housing HCU, as shown in FIG. 4 in the upper half of the drive shaft 1. Before the pump housing 40 and hydraulic housing HCU or pump housing 40 and ECU are assembled, the gear pump Z is first integrated or mounted in the pump housing 40, the rotor 21 then being pressed onto the shaft 1 and then assembled with the bearing 20. Here, the tensile force of the magnet 30 can also act on the rotor 21 and the bearing 20, so that the bearing acts like a four-point bearing. The motor housing 22 is thus connected to the gear pump Z and its pump housing 40 and, in the next step, can be connected to the hydraulic housing HCU or the electronics housing ECU. For this purpose, the fastening screw 41 is used. The shaft 1 is previously centered in the outer disks 7.1 and 7.2 so that the pump housing 40 is centered with the shaft 1 before the screw connection to the hydraulic housing HCU or the electronics housing ECU.

The pressure supply device according to FIG. 4a uses a 2-stage pump with a long sliding or roller bearing according to FIGS. 2 and 3, which does not require a separate motor bearing. Accordingly, the Motorauf construction is simplified with the housing. The rotor 21 sits with driver 10a on the motor shaft and is axially connected to the locking ring. The pump housing protrudes slightly into the HCU here.

Fig. 5 shows the assembly device for welding the discs 7.1 and 7.2 together with the outer ring 4. For this purpose, a sleeve 37 is pushed over the drive shaft and axially fixed with the locking ring. The disks 7.1, 7.2 and the outer ring are then centered via the centering sleeve 35. On on the opposite side, the washers 7.1, 7.2 are axially clamped together with the outer ring with the nut 34 via the assembly washer 33. After removal of the centering sleeve, LS can then preferably be laser welded. For this purpose, the sleeve is clamped in a rotatable manner. As Fig. Lb shows, the diameter of the weld is smaller, so that the later assembly in the flange is not hindered.

Reference list

1 drive shaft

lb end of the drive shaft

2 internal gear (toothed ring)

3 internal ring gear

4 outer ring

5 guide part (sickle)

5a 2-part sickle

5b balance spring

6 Fixation of the sickle

6a fixation alternative

7.1 Outer pane 1

7.2 Outer pane 2

8 threaded studs

9 Anti-twist device

10 carriers

10a driver to the rotor

11 guide band

12 waves

13.1 Seal

13.2 Seal

14 Outer pane seal

15 leakage flow channel

16 plain bearings

17 rolling bearings

17a rolling bearings

18 wall of the drive housing, which is the first housing part of the

Motor housing, in particular as a bearing flange or side wall, is formed

18b recess in the side wall

18f window-like recess for drive shaft

18k channel

19 center disk

20 engine mounts

21 rotor

21a stator

22 motor housing

23 Motor winding

24 Motor contact

25 Housing mounting

25a alternative housing attachment

26 sensor shaft

27 target 28 Sensor element on circuit board

29 Circlip

30 housing with magnet 30a

30a magnet

31 Housing seal

32 brush DC motor

33 mounting washer

34 mother

35 centering sleeve

36 moment support

37 sleeve

38 Circlip

39 Rolling Bearings

40 pump housing

41 fixing screw

45 Side wall of the hydraulic housing

46 recess in the side wall 46 of the hydraulic housing

48 channel for electrical cables

B Axial width of the inner gear 2

D seal

S Suction connection with seal

P pressure connection with seal

LS laser welding

HCU hydraulic block

HCUsi side of the hydraulic housing facing the drive housing

HCU _S 2 side of the hydraulic housing facing the electronics housing

ECU electronic control unit

Sa, Pa orifices of channels S and P

Z gear pump

ZG gear pump housing

Claims

1. Gear pump (Z) in the form of an internal gear pump or a toothed ring pump or gerator pump, with an internal gear (2) driven by a drive shaft (1) and an internal gear (3), where the axis (2a) of the internal gear ( 2) is arranged coaxially to the axis (3a) of the internal gear rim (3), and that the inner gear wheel (2) and the internal gear rim (3) share in the axial direction between two housings (7.1, 7.1b, 7.2) are arranged, the Housing parts (7.1, 7.1b, 7.2) directly or via at least one part (4) arranged between them, in particular in the form of a ring, are materially connected to each other or that the housing parts (7.1, 7.1a, 7.2) by means of at least one elastic and / or resilient part (41) are pressed against each other ge.

2. Gear pump (Z) according to claim 1, characterized in that in the axial direction at least on one side next to the inner gear (2) and the inner ring gear (3) an outer disc (7.1, 7.2) is angeord net, which is a housing part of the gear pump (Z) forms, wherein a) when the gear pump (Z) is designed as an internal gear pump, the internal gear rim (3) is enclosed by an outer part (4), the at least one outer disk (7.1, 7.2) cohesively with the outer part (4) connected is,

or that

b) when the gear pump (Z) is designed as a gerotor pump either

- The inner ring gear (3) is surrounded by an outer part (4), in which case the at least one outer disk (7.1, 7.2) is or is cohesively connected to the outer part (4)

- The inner ring gear (3) itself with the at least one outer disc (7.1, 7.2) is firmly connected.

3. Gear pump (Z) according to claim 1 or 2, characterized in that the material connection is a weld, solder or adhesive connection.

4. Gear pump (Z) according to claim 1 or 2, characterized in that an outer disc (7.1, 7.2) is arranged in the axial direction at least on one side next to the inner gear (2) and the internal gear rim (3), wherein in the installed state of the gear pump (Z) at least one elastic and / or resilient part (41), in particular in the form of a ring, in the axial direction a force (Fa) on an outer disk (7.1, 7.2) and / or an inner gear (2) and the inner ring gear (3) exercising cup-shaped part (7.1b).

5. Gear pump (Z) according to claim 4, characterized in that the part (41) in a circular groove (7.2a) of an outer disk (7.2) or a groove (7.1bn) arranged in the flat outer side (7.2a) of the cup-shaped part (7.1b) rests and is supported on a side surface of an adjacent part (46).

6. Gear pump (Z) according to one of the preceding claims, characterized in that the outer part (4) is a ring, a sleeve, a pot-shaped part (7.1b) or a bearing (17a).

7. Gear pump (Z) according to one of the preceding claims, characterized in that the composite of the drive shaft (1), the inner gear (2) and the inner ring gear (3), and the housing parts (7.1, 7.1b, 7.2) and if requires the outer part (4) to form a structural unit or a module.

8. Gear pump (Z) according to claim 7, characterized in that the composite in a sleeve, a cylindrical recess (18b) of a part, in particular in the form of a housing wall (18) of a motor, a motor flange, a pump housing (40) and / or a Ge housing (HCU) for hydraulic units is arranged.

9. gear pump (Z) according to one of claims 1 to 8, characterized draws that in the axial direction on both sides of the inner Zahnra des (2) and the inner ring gear (3) each have a disc (7.1, 7.2) is arranged.

10. Gear pump (Z) according to claim 9, characterized in that the two disks (7.1, 7.2) and the inner ring gear (3) or the outer ring (4) have the same outer diameter.

11. Gear pump (Z) according to one of claims 1 to 10, characterized in that the adjacent outer radial edge areas (7.1a, 7.2a, 3a) of the two discs (7.1, 7.2) and the internal gear rim (3) or the outer part (4) connected to one another, in particular welded, soldered or glued to one another.

12. Gear pump according to claim 11, characterized in that at least one outer radial edge region (7.1a, 7.2a, 3a, 4a) is formed by a bevel, which is used in particular for welding or soldering.

13. Gear pump according to one of the preceding claims, characterized in that the gear pump is an internal gear pump in which a sealing element (5), in particular in the form of a sickle, is arranged between the internal gear (2) and the internal gear rim (3).

14. Gear pump according to claim 13, characterized in that the Si chel (5) is slidably mounted in the gear pump (Z), in particular between two bearing parts or fixings (6, 6a).

15. Gear pump according to claim 13 or 14, characterized in that the sickle (5) is in one or two parts (5a, 5b).

16. Gear pump according to one of claims 13 to 15, characterized in that the sickle (5) by means of an adjusting mechanism (6, 6a), in particular in the form of a spring or a rotatable part (5b), in particular in the form of an eccentric, which is designed as a pin, is adjustable or lockable relative to the internal gear (2).

17. Gear pump according to one of claims 13 to 16, characterized in that the sickle (5), in particular its contact surface to the inner Ren gear (2), and / or the teeth of the inner gear (2) at their outer radial ends, Depressions, in particular in the form of grooves, which in particular extend in the circumferential direction, have the same for pressure compensation.

18. Gear pump (Z) according to one of the preceding claims, characterized in that, in the case of the gerotor pump, one of a drive shaft (1) driven and rotatable about an axis (A1) has Gela part (42), the axis of rotation (A2 ) of the inner gear (2) is arranged eccentrically to the axis (Al).

19. Gear pump (Z) according to one of the preceding claims, characterized in that the internal gear (2) is arranged tiltable to the drive shaft (1), in particular is coupled to the drive shaft (1) by means of an elastic and / or flexible connection.

20. Gear pump (Z) according to one of the preceding claims, characterized in that the internal gear (2) has a maximum axial width (B), the axial length of the contact surface with which the internal gear (2) on the drive shaft (1 ) is applied, is shorter than the maximum axial width (B) and / or that a part made of elastic and / or flexible material is arranged between the gear wheel (2) and the drive shaft (1) to compensate for tolerances.

21. Pressure supply device with an electric motor drive (21, 21a) arranged in a drive housing (18, 22) with a stator (21a) and a rotor (21), as well as a gear pump (Z) driven by the drive (21, 21a) according to one of the preceding claims.

22. Pressure supply device according to claim 21, characterized in that the inner gear (2) of the gear pump (Z) is coupled directly or via a clutch and / or a gear to the rotor (21), a wall (18) between the Rotor (21) and the gear (2) is arranged, and that at least one seal (13.1) between the rotor gate (21) and gear (2) is arranged in such a way that the rotor (21) is a dry-running rotor (21) which does not flow around and / or surrounded by the medium conveyed by the gear (2).

23. Pressure supply device according to claim 22, characterized in that the drive housing (18, 22) has a side wall (18a, 40) on which the gear pump (Z) is arranged or in which, in particular in a recess (18b), the gear pump (Z) is at least partially or completely inserted.

24. Pressure supply device according to one of claims 21 to 23,

characterized in that the drive (21, 21a) rests on a hydraulic housing (HCU) with at least one valve and / or hydraulic lines or channels arranged therein or forms a unit with this

25. Pressure supply device according to claim 24, characterized in that the gear pump (Z) in the recess (18b) of the side wall (18) or in an, in particular cup-shaped, pump housing (40), which is in particular on the hydraulic housing (HCU) is attached, rests or both in the recess (18b) of the side wall (18) or in a pump housing (40) and in a recess (45) of the hydraulic housing (HCU), the openings of the recesses (18b, 41) to each other are facing, lies.

26. Pressure supply device according to one of claims 21 to 25,

characterized in that the recess (18b) is open towards the hydraulic housing (HCU), in particular is cup-shaped.

27. Pressure supply device according to one of claims 21 to 26,

characterized in that at least one seal (D, 31a) is arranged in the side wall (18) and / or in a first hydraulic housing side wall (46) corresponding to the side wall (18).

28. Pressure supply device according to one of claims 21 to 27, characterized in that the gearwheel (2) is non-rotatably connected to the drive shaft (1) by means of a force-locking connection or by means of a form-locking connection, which is formed in particular by means of a pin or serration.

29. Pressure supply device according to one of claims 21 to 28,

characterized in that the gear pump (Z) is an internal gear pump with, in particular a permanently arranged, sickle (5), an external gear pump or a gerotor pump.

30. Pressure supply device according to one of claims 21 to 29,

characterized in that the internal gear pump (Z), in addition to the gear (2), which is designed as an internal gear, also has an external internal gear (3) and a sickle (5), the rotor (21) with the internal gear ( 2) is coupled by means of a drive shaft (1) directly, via a coupling and / or via a transmission.

31. Pressure supply device according to one of claims 21 to 30,

characterized in that the drive shaft (1) is either a) in the drive housing (22) on the one hand and in the gear pump (Z) and / or in the hydraulic housing (HCU) on the other hand or b) only in the gear pump (Z) or c) in Hydraulic housing (HCU) and in the drive housing (22) or d) is supported in the gear pump (Z) and in the hydraulic housing (HCU) or is supported by means of suitable bearings, in particular radial bearings and / or axial bearings.

32. Pressure supply device according to one of the preceding claims, characterized in that the drive shaft (1) is non-rotatably connected to the rotor (21).

33. Pressure supply device according to one of claims 21 to 32,

characterized in that the side wall (18) has a window-like Opening (18f), in particular in the form of a bore, through which the drive shaft (1) extends, an annular seal (13.1) surrounding the drive shaft (1) serving to seal the window-like opening (18f).

34. Pressure supply device according to one of claims 21 to 33,

characterized in that the side wall (18) or the first housing part (18) is designed as a bearing flange and is fastened or can be fastened to the hydraulic housing (HCU) by means of fastening means, in particular screws.

35. Pressure supply device according to one of claims 21 to 34,

characterized in that on the side (HCU _S2 ) of the hydraulic housing (HCU) opposite the first hydraulic housing side (HCUsi) a control and regulating device (ECU) with its housing (ECU _G ) is arranged.

36. Pressure supply device according to claim 35, characterized in that the drive shaft (1) or a part (26) arranged thereon extends into the hydraulic housing (HCU), in particular up to its opposite side (HCU _S2 ), or the hydraulic housing (HCU) takes full action.

37. Pressure supply device according to claim 36, characterized in that the drive shaft (1) or a part (26) arranged thereon carries a target (27).

38. Pressure supply device according to one of claims 21 to 37,

characterized in that the internal gear (2) has a maximum axial width (B), the axial length of the contact surface with which the internal gear (2) rests on the drive shaft (1) is shorter than the maximum axial width (B ) and / or the internal gear (2) is arranged tiltably on the drive shaft (1).

39. Pressure supply device according to one of claims 21 to 38,

characterized in that the electrical connections (24) of the electric drive (21, 23) through a channel (18f) of the Seitenwan extension (18) and a channel (48) of the hydraulic housing (HCU) are passed.

40. Pressure supply device according to one of claims 21 to 39,

characterized in that the drive shaft (1) is mounted with its second end (lb) in the second housing (22).

41. Pressure supply device according to one of claims 21 to 40,

characterized in that the gear pump (Z) is arranged wholly or partially next to the rotor (21) in the axial direction.

42. Pressure supply device according to one of claims 21 to 41,

characterized in that the internal gear (2), the cup-shaped part (7.1b) and / or a bearing plate (7.1, 7.2) forms bearings for the drive shaft (1).

43. Pressure supply device according to one of claims 21 to 42,

characterized in that the pressure supply device serves as a pressure source for a brake system and / or a transmission.

44. Pressure supply device according to one of claims 21 to 43,

characterized in that several electric motors and gear pumps (Z) are arranged in a drive housing.

45. Pressure supply device according to one of claims 21 to 44,

characterized in that several pressure supply devices are combined to form a module or structural unit.

46. Pressure supply device according to one of claims 21 to 45,

characterized in that a bearing, in particular in the form of a ball or roller bearing, is between the radial outer wall of the inner gear rim (3) and the outer ring (4) surrounding the inner gear rim (3) or the cylindrical inner wall of the cup-shaped part (40 ) be provided in order to keep the friction as low as possible.

47. Pressure supply device according to one of claims 21 to 46, characterized in that at least one permanent magnet (30a) is provided in the housing (30) which exerts an axial force (F) on the rotor (21).

48. Brake system or transmission with a pressure supply device according to one of the preceding claims 21 to 47 or with a gear pump according to one of claims 1 to 20.