GEAR PUMP

Abstract

A gear pump having a pump housing, a rotatably mounted drive shaft extending into the pump housing, and a rotor of a drive motor. The rotor is attached in a rotationally fixed manner on the drive shaft, and at least one drive gearwheel which is arranged in a rotationally fixed manner on the drive shaft in the pump housing. At least one gearwheel is driven by the drive gearwheel, wherein the drive gearwheel is fixed axially on the drive shaft. The drive gearwheel together with the pump housing forms an axial bearing for the rotor.

Claims

1. Gear pump having a pump housing, a rotatably mounted drive shaft extending into the pump housing, a rotor of a drive motor, said rotor being attached in a rotationally fixed manner on the drive shaft, at least one drive gearwheel which is arranged in a rotationally fixed manner on the drive shaft in the pump housing, and at least one gearwheel driven by the drive gearwheel, wherein the drive gearwheel is fixed axially on the drive shaft, and wherein the drive gearwheel together with the pump housing forms an axial bearing for the rotor.

2. Gear pump according to claim 1, wherein the at least one drive gearwheel is pressed or injection-moulded onto the drive shaft or is fixed axially on the drive shaft by means of a stop element, in particular by means of a securing ring.

3. Gear pump according to claim 1, wherein a second drive gearwheel is mounted on the drive shaft at a distance from the first drive gearwheel, wherein an intermediate element is present radially between the second drive gearwheel and the drive shaft, said intermediate element being in torque-transmitting engagement both with the drive shaft and with the second drive gearwheel, wherein the intermediate element is shorter than the second drive gearwheel as viewed in the axial direction.

4. Gear pump according to claim 3, wherein the second drive gearwheel is mounted on the intermediate element with play.

5. Gear pump according to claim 3, wherein the intermediate element is pressed or injection-moulded onto the drive shaft.

6. Gear pump according to claim 3, wherein two driven gearwheels are in engagement with each of the drive gearwheels.

7. Gear pump according to claim 1, wherein the gear pump is single-layered, wherein the drive gearwheel is in meshed engagement with two driven gearwheels, which in turn are in engagement with in each case one further driven gearwheel at a distance from the drive gearwheel.

8. Gear pump according to claim 1, wherein at least one oil intake duct is formed in the pump housing and extends from an oil intake opening in an underside of the pump housing to a gearwheel pair.

9. Gear pump according to claim 1, wherein the pump housing is adjoined by a motor housing in which the drive motor for driving the drive shaft is arranged, wherein at least one fluid duct runs from the pump housing into the motor housing.

10. Gear pump according to claim 1, wherein the drive motor is an electric motor.

11. Gear pump according to claim 2, wherein a second drive gearwheel is mounted on the drive shaft at a distance from the first drive gearwheel, wherein an intermediate element is present radially between the second drive gearwheel and the drive shaft, said intermediate element being in torque-transmitting engagement both with the drive shaft and with the second drive gearwheel, wherein the intermediate element is shorter than the second drive gearwheel as viewed in the axial direction.

12. Gear pump according to claim 4, wherein the intermediate element is pressed or injection-moulded onto the drive shaft.

13. Gear pump according to claim 4, wherein two driven gearwheels are in engagement with each of the drive gearwheels.

14. Gear pump according to claim 2, wherein the gear pump is single-layered, wherein the drive gearwheel is in meshed engagement with two driven gearwheels, which in turn are in engagement with in each case one further driven gearwheel at a distance from the drive gearwheel.

15. Gear pump according to claim 2, wherein at least one oil intake duct is formed in the pump housing and extends from an oil intake opening in an underside of the pump housing to a gearwheel pair.

16. Gear pump according to claim 2, wherein the pump housing is adjoined by a motor housing in which the drive motor for driving the drive shaft is arranged, wherein at least one fluid duct runs from the pump housing into the motor housing.

17. Gear pump according to claim 2, wherein the drive motor is an electric motor.

18. Gear pump according to claim 5, wherein two driven gearwheels are in engagement with each of the drive gearwheels.

19. Gear pump according to claim 3, wherein at least one oil intake duct is formed in the pump housing and extends from an oil intake opening in an underside of the pump housing to a gearwheel pair.

20. Gear pump according to claim 3, wherein the pump housing is adjoined by a motor housing in which the drive motor for driving the drive shaft is arranged, wherein at least one fluid duct runs from the pump housing into the motor housing.

Description

[0027] Further advantages and features can be found in the following description and the appended drawings. In the drawings:

[0028] FIG. 1 shows a gear pump according to the invention in a first embodiment,

[0029] FIG. 2 shows a longitudinal section through the gear pump from FIG. 1,

[0030] FIG. 3 shows a cross section through the gear pump along line A-A in

[0031] FIG. 2,

[0032] FIG. 4 shows a cross section through the gear pump along line B-B in

[0033] FIG. 2,

[0034] FIG. 5 shows a cross section through the gear pump along line C-C in FIG. 2,

[0035] FIG. 6 shows the gear pump from FIG. 1 in a perspective view,

[0036] FIG. 7 shows a gear pump according to the invention in a further embodiment,

[0037] FIG. 8 shows a cross section through the gear pump from FIG. 7,

[0038] FIG. 9 shows a longitudinal section through the gear pump from FIG. 7, and

[0039] FIG. 10 shows a perspective view of the gear pump from FIG. 7.

[0040] FIG. 1 shows a gear pump 10.

[0041] The gear pump 10 comprises a pump housing 12 and a motor housing 14.

[0042] In FIG. 1, the gear pump 10 is mounted on an oil sump 16.

[0043] FIG. 1 also shows a further pump 18, which is likewise mounted on the oil sump 16. However, the further pump 18 is not discussed in detail.

[0044] The pump housing 12, the motor housing 14 and the oil sump 16 are preferably manufactured from plastic.

[0045] Gearwheels of the gear pump 10 are accommodated in the pump housing 12, while a drive motor 20 is accommodated in the motor housing 14, as can be seen in FIG. 2.

[0046] The drive motor 20 is preferably potted in the motor housing 14.

[0047] The drive motor 20 drives a drive shaft 22, which extends into the pump housing 12.

[0048] The drive motor 20 is an electric motor and comprises a rotor 24, which is attached in a rotationally fixed manner on the drive shaft 22, and a stator 25.

[0049] A first drive gearwheel 26 and a second drive gearwheel 28 are arranged in a rotationally fixed manner on the drive shaft 22 inside the pump housing 12.

[0050] The two drive gearwheels 26, 28 are axially spaced from one another.

[0051] In the exemplary embodiment, the first drive gearwheel 26 is arranged directly on the drive shaft; that is, there is no intermediate element between the drive shaft 22 and the drive gearwheel 26.

[0052] For example, the first drive gearwheel 26 is pressed or injection-moulded onto the drive shaft 22.

[0053] Alternatively, the first drive gearwheel 26 can be axially fixed on the drive shaft 22 by means of a stop element, in particular by means of a securing ring.

[0054] An intermediate element 30 is arranged radially between the second drive gearwheel 28 and the drive shaft 22.

[0055] The intermediate element 30 is in torque-transmitting engagement both with the drive shaft 22 and with the second drive gearwheel 28.

[0056] The intermediate element 30 is shorter than the second drive gearwheel 28 as viewed in the axial direction, as a result of which flexible positioning of the second drive gearwheel 28 relative to the intermediate element 30 is possible.

[0057] The second drive gearwheel 28 is mounted on the intermediate element 30 with play, as a result of which a sliding guide is realized.

[0058] An axial movement of the first drive gearwheel 26 and of the second drive gearwheel 28 is limited, in particular by the fact that a wall of the pump housing 12 is arranged at both end faces of the drive gearwheels 26, 28. Specifically, the pump housing 12 has two end walls 32, 34 and an intermediate wall 36.

[0059] However, the drive gearwheels 26, 28 have a small axial play in the pump housing 12 to compensate manufacturing tolerances and thermal expansions.

[0060] Since the first drive gearwheel 26 is only axially displaceable together with the drive shaft 22, the first drive gearwheel 26 together with the pump housing 12 forms an axial bearing for the rotor 24.

[0061] The drive shaft 22 is also supported radially in the pump housing 12, in particular in both end walls 32, 34 of the pump housing 12.

[0062] As can be seen both in FIG. 2 and in FIGS. 3 and 4, in each case two driven gearwheels 38, 40, 42, 44 are in engagement with each of the drive gearwheels 26, 28. The gear pump 10 is thus a four-flow gear pump.

[0063] Since the gearwheels 26, 28, 38, 40, 42, 44 are arranged in two layers, as can be seen in FIG. 2, such a structure is known as a two-layered design. A particularly narrow construction of the gear pump 10 can be realized by a two-layered design.

[0064] The driven gearwheels 38, 40, 42, 44 each sit on a shaft 46, 48 with play and run freely with the drive gearwheels 26, 28.

[0065] FIG. 4 shows the torque-transmitting connection between the second drive gearwheel 28 and the intermediate element 30 in detail.

[0066] In the exemplary embodiment, the intermediate element 30 is coupled in torque-transmitting fashion to the second drive gearwheel 28 by means of a spline connection.

[0067] The intermediate element 30 is pressed or injection-moulded on the drive shaft 22.

[0068] FIGS. 3 and 4 also show oil intake ducts 50, which each extend from an oil intake opening 52 in an underside of the pump housing 12 to a gearwheel pair.

[0069] The oil intake ducts 50 run in the pump housing 12 and are formed by corresponding cut-outs in the pump housing 12.

[0070] The oil intake ducts 50 run on both sides of the intermediate wall 36 in the pump housing 12. In the exemplary embodiment, the pump housing 12 overlaps with the gearwheels 26, 28, 38, 40, 42, 44 and has cut-outs in which the gearwheels 26, 28, 38, 40, 42, 44 are accommodated.

[0071] In the perspective view in FIG. 6, the oil intake openings 52 can be seen in the underside of the pump housing 12.

[0072] When the gear pump 10 is placed onto the oil sump 16, oil can be sucked in directly out of the oil sump 16.

[0073] FIG. 5 shows a section through the gear pump 10 running through the end wall 32 which separates the pump housing 12 from the motor housing 14.

[0074] In the end wall 32 there are fluid ducts 54, which are formed by cut-outs in the end wall 32 and run into the motor housing 14, as a result of which cooling of the drive motor 20 is realized.

[0075] FIGS. 7 to 10 show a gear pump 10 according to a further embodiment.

[0076] In the following, the same reference signs are used for identical structures with identical functions known from the above embodiment, and reference is made to the previous explanations in this respect; the differences between the respective embodiments are discussed below to avoid repetition.

[0077] A single-layered design is realized in the gear pump 10 of FIGS. 7 to 10, which means that all the gearwheels 26, 38, 40, 42, 44 lie in one plane.

[0078] As a result, the construction of the gear pump 10 is particularly flat.

[0079] In addition, only five gearwheels in total are needed for a four-flow design, while six gearwheels are needed to realize a four-flow design in the embodiment shown in FIGS. 1 to 6.

[0080] The drive gearwheel 26 is likewise fixed axially on the drive shaft 22, wherein this is realized by a stepped portion in the drive shaft 22 in combination with a securing ring 56 (see FIG. 9).

[0081] The rotationally fixed coupling between the drive shaft 22 and the drive gearwheel 26 is achieved by flattened portions 58 on the drive shaft 22, as can be seen in FIG. 8.

[0082] However, it is also conceivable for the drive gearwheel 26 to be pressed or injection-moulded onto the drive shaft 22, as in the previous embodiment.

[0083] The drive gearwheel 26 is in meshed engagement with two driven gearwheels 38, 40, which in turn are each in engagement with one further driven gearwheel 42, 44 at a distance from the drive gearwheel 26.

[0084] The driven gearwheels 38, 40 which are in engagement with the drive gearwheel 26 thus each form a drive gearwheel for the further gearwheels 42, 44.

[0085] In the embodiment according to FIGS. 7 to 10, the drive shaft 22 is in two parts, wherein the two parts 60, 62 of the drive shaft 22 are inserted into one another telescopically. As a result, the part 60 of the drive shaft 22 to be overmoulded with the rotor 24 can be kept simple, while the part 62 of the drive shaft 22 with the flattened portions 58 is produced as an extruded part, for example. The part 62 is pressed onto the overmoulded part 60, for example.