Method for operating a gear pump, and gear pump

Abstract

The invention concerns a method for operating a gear pump, in particular for delivering engine oil in an oil circuit of a vehicle, wherein a delivery device is provided with at least two gear wheels, in particular with external toothing or configured as spur gears and arranged in a housing, wherein by means of the gear wheels a fluid to be conveyed can be delivered starting from at least one housing inlet through to at least one housing outlet, and wherein the gear wheels are arranged behind each other viewed in the axial direction (x). According to the invention, an adjustment device is provided, by means of which the gear wheels can be twisted and/or displaced relative to each other depending on the pressure conditions inside the housing, in particular depending on the vacuum pressure at the housing inlet and/or depending on the fluid back-pressure at the housing outlet.

Claims

1. A method for operating a gear pump for delivering engine oil in an oil circuit of a vehicle, comprising: providing a delivery device with at least two gear wheels arranged in a housing, the at least two gear wheels at least one of having external toothing or configured as spur gears, and are arranged behind each other viewed in an axial direction (x); delivering a fluid to be conveyed by the gear wheels through the housing from at least one housing inlet to at least one housing outlet, at least one of twisting or displacing the gear wheels relative to each other by an adjustment device depending on pressure conditions Inside the housing, the pressure conditions being at least one of a vacuum pressure at the housing inlet and a fluid back-pressure pt the housing outlet, wherein the adjustment device includes a fixing device connecting a first gear wheel of the gear wheels forming an adjustment gear to the housing, wherein the adjustment gear is at least one of displaceable and twistable relative to a second gear wheel of the gear wheels by the fixing device, and the adjustment device has a torsion spring that pretensions the adjustment gear toward a base position, and wherein the gear wheels have a identical radial outer contour, the gear wheels in a base position are arranged flush with each other viewed in the axial direction (x), and the step of at least one of twisting and displacing includes moving the gear wheels into the base position, from a position not corresponding to the base position, by the adjustment device when the fluid back-pressure at the housing outlet lies below a minimum value.

2. The method according to claim 1, wherein the gear wheels are arranged in the housing such that rotation axes of the gear wheels are oriented parallel to each other.

3. The method according to claim 1, wherein the step of at least one of twisting and displacing includes at least one of axially twisting the gear wheels and displacing the gear wheels in the radial direction relative to each other by the adjustment device depending on the pressure conditions inside the housing.

4. The method according to claim 1, wherein, when the fluid back-pressure at the housing outlet is not below the minimum value, the step of at least one of twisting and displacing the gear wheels includes at least one of twisting and displacing the gears wheels out of the base position by the adjustment device.

5. The method according to claim 4, wherein, when the fluid back-pressure at the housing outlet exceeds a defined maximum value, the step of at least one of twisting and displacing includes moving the gear wheels into a maximum position in which the gear wheels are arranged twisted relative to each other by a half tooth pitch, the maximum value being greater than the minimum value.

6. A gear pump for delivering engine oil in an oil circuit of a motor vehicle, comprising: a delivery device including at least two gear wheels arranged in a housing, the gear wheels at least one of having an external toothing and configured as spur gears, the gear wheels being configured to deliver a fluid to be conveyed through the housing from at least one housing inlet to at least one housing outlet, and the gear wheels being arranged behind each other in the axial direction (x); and an adjustment device configured to at least one of twist and displace the gear wheels relative to each other depending on pressure conditions inside the housing, the pressure conditions being at least one of a vacuum pressure at the housing inlet and a fluid back-pressure at the housing outlet, wherein the adjustment device includes a fixing device connecting a first gear wheel of the gear wheels forming an adjustment gear to the housing, wherein the adjustment gear is at least one of displaceable and twistable relative to a second gear wheel of the gear wheels by the fixing device, and the adjustment device has a torsion spring that pretensions the adjustment gear toward a base position, wherein the gear pump is an internal near pump and the at least two gear wheels are externally toothed gear wheels which intermesh with at least one internally toothed gear element.

7. The gear pump according to claim 6, further comprising at least one stop cooperating with the torsion spring to prevent the twisting and displacement of the adjustment gear arranged in the base position in at least one defined direction.

8. The gear pump according to claim 6, wherein the adjustment gear at least one of moves and twists from the base position relative to the second gear wheel under the defined pressure conditions in the housing, and the torsion spring is tensioned by this displacement and/or twist of the adjustment gear from the base position and generates a return force.

9. The gear pump according to claim 6, further comprising a stop that limits at least one of a displacement and a twist of the adjustment gear from the base position.

10. The gear pump according to claim 6, wherein the fixing device comprises a fixing element connecting the adjustment gear to the housing displaceably relative to the housing, wherein the adjustment gear is fixed rotatably to the fixing element so as to form a first rotation axis (A.sub.1), the fixing element is fixed rotatably to the housing so as to form a second rotation axis (A.sub.2) arranged parallel to the first rotation axis (A.sub.1), and the adjustment gear is displaceable relative to the housing by rotating the fixing element.

11. The gear pump according to claim 10, wherein the fixing element is Z-shaped.

12. The gear pump according to claim 10, wherein the torsion spring is tensioned by rotating the fixing element in a first rotation direction (R.sub.1) about the second rotation axis (A.sub.2), and the torsion spring can be released by rotating the fixing element in a second rotation direction (R.sub.2) opposite the first rotation direction (R.sub.1).

13. The gear pump according to claim 12, wherein an end region of the torsion spring is connected to a region of the fixing element protruding from the housing.

14. A vehicle with an internal combustion engine including a gear pump according to claim 6.

15. A gear pump for delivering engine oil in an oil circuit of a motor vehicle, comprising: a delivery device including at least two gear wheels arranged in a housing, the gear wheels at least one of having an external toothing and configured as spur gears, the gear wheels being configured to deliver a fluid to be conveyed through the housing from at least one housing inlet to at least one housing outlet, and the gear wheels being arranged behind each other in the axial direction (x); and an adjustment device configured to at least one of twist and displace the gear wheels relative to each other depending on pressure conditions inside the housing, the pressure conditions being at least one of a vacuum pressure at the housing inlet and a fluid back-pressure at the housing outlet, wherein the adjustment device includes a fixing device connecting a first gear wheel of the gear wheels forming an adjustment gear to the housing, wherein the adjustment gear is at least one of displaceable and twistable relative to a second gear wheel of the gear wheels by the fixing device, and the adjustment device has a torsion spring that pretensions the adjustment gear toward a base position, and wherein the gear pump is an external gear pump, the at least two gear wheels including externally toothed gear wheels forming drive gears for driving the external gear pump, and each of the drive gears intermeshing with a corresponding externally toothed gear wheel.

16. The gear pump according to claim 15, wherein the fixing device includes a drive shaft mounted rotatably on the housing for driving the drive gears, wherein at least one of the drive gears is connected rotationally fixedly to the drive shaft, and at least another of the drive gears forming the adjustment gear is fixed to the drive shaft axially twistably relative to the drive shaft, and wherein the drive gears are connected in a torque-transmissive fashion by the torsion spring.

17. The gear pump according to claim 16, wherein the torsion spring is tensioned by rotating the adjustment gear relative to the drive shaft in a first rotation direction, and the torsion spring can be released by rotating the adjustment gear relative to the drive shaft in a second rotation direction opposite the first rotation direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings,

(2) FIG. 1 is a top view of an internal gear pump according to the invention with a top of the housing removed, in a first operating situation;

(3) FIG. 2 is a depiction according to FIG. 1, with the internal gear pump in a second operating situation;

(4) FIG. 3 is a diagrammatic section view of an adjustment device of the internal gear pump;

(5) FIG. 4 is a diagrammatic depiction illustrating the function of the adjustment device of FIG. 3;

(6) FIG. 5 is a view from above of an external gear pump according to another embodiment of the invention with a top removed from housing, in a first operating situation;

(7) FIG. 6 is a depiction according to FIG. 5 with the external gear pump in a second operating situation; and

(8) FIG. 7 is a diagrammatic section view of an adjustment device for the external gear pump.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) FIG. 1 shows a gear pump, here formed for example as an internal gear pump 1. The internal gear pump 1 has a housing 3 which is shown open in FIG. 1, i.e. with a top removed so that the gears are visible. The housing 3 has a housing inlet 5 and a housing outlet 7. By means of the housing inlet 5 and the housing inlet 7, the internal gear pump 1 may be connected for example to an oil circuit of the vehicle, so that the oil to be conveyed by the internal gear pump 1 passes via the housing inlet 5 into the interior of the housing 3 and emerges from the housing 3 again via the housing outlet 7.

(10) As furthermore shown in FIG. 1, the internal gear pump 1 has an internally toothed gear wheel arranged inside the housing 3 and here configured for example as a spur gear 9, which forms a drive gear for driving the internal gear pump 1. The internally toothed spur gear 9 intermeshes with a plurality of, here for example two, externally toothed gear wheels also configured as spur gears 11, 13. The externally toothed spur gears 11, 13 are here configured for example identically or with identical design, and viewed in the axial direction x (FIG. 3) are arranged behind each other in the housing 3 with a defined spacing. To drive the internal gear pump 1, the internally toothed spur gear 9 is driven rotationally by a suitable drive device, not shown in the figures. The externally toothed spur gears 11, 13 intermeshed with the internally toothed spur gear 9 are then also driven in rotation by the internally toothed spur gear 9. In this way, the fluid to be conveyed is delivered from the housing inlet 5 to the housing outlet 7 via tooth gaps 15, forming delivery chambers, of the externally toothed face spur wheels 11, 13.

(11) According to FIG. 1, the externally toothed spur gear 13 is here fixed as an example axially rotatably on a shaft 19. The shaft 19 is here for example fixed rigidly or immovably to the housing 3. The externally toothed spur gear 11 is here for example mounted on the housing 3 displaceably and rotatably relative to the externally toothed spur gear 13 by an adjustment device 21 (FIG. 3). The externally toothed spur gear 11 may for example be arranged, by the adjustment device 21, in a base position shown in FIG. 2, in which the externally toothed spur gears 11, 13 are arranged flush with each other in the axial direction x or viewed in top view. The rotation axes of the spur gears 11, 13 are then aligned congruent to each other. Also, the externally toothed spur gear 11 may here for example also be arranged in a maximum position, in which the externally toothed spur gears 11, 13 are arranged twisted relative to each other by half a tooth pitch. FIG. 1 shows the externally toothed spur gear 11 arranged in a position between the base position and the maximum position. Here the rotation axes of the spur gears 11, 13 are then oriented parallel to each other for example.

(12) As shown from FIG. 3, the adjustment device 21 has a fixing device 23, which fixes the gear wheel 11 forming the adjustment gear to the housing 3 movably or rotatably relative to the housing 3 and hence also to the spur gear 13. The fixing device 23 here comprises for example a substantially Z-shaped fixing element 25 which has a shaft 27, forming a first rotation axis A.sub.1, on which the adjustment gear 11 is fixed axially rotatably. Also, the fixing element has a shaft 29, forming a second rotation axis A.sub.2, by means of which the fixing element 25 is fixed rotatably to the housing 3. The shafts 27, 29 are here configured offset to each other such that the second rotation axis A.sub.2 is arranged parallel to the first rotation axis A.sub.1. By turning the fixing element 25 about the second rotation axis A.sub.2, the adjustment gear 11 can thus be twisted and displaced relative to the spur gear 13.

(13) According to FIG. 3, the adjustment device 21 furthermore has a pretension element, here configured for example as a torsion spring 31, which pretensions the adjustment gear 11 in the base position (FIG. 2). The torsion spring 31 is here tensioned for example by turning the fixing element 25 about the second rotation axis A.sub.2 in a first rotation direction R.sub.1 (FIG. 4). By turning the fixing element 25 about the second rotation axis A.sub.2 in a second rotation direction R.sub.2 (FIG. 4) opposite the first rotation direction, the torsion spring 31 can be released. The torsion spring 31 is here fixed for example with an end region 33 to an end region 35 of the fixing element 25 protruding from the housing 3, and with a second end region 37 immovably or rigidly to the vehicle-side fixing point 39.

(14) Furthermore, the adjustment element 25 is here pretensioned by the torsion spring 31 against a stop element 41, depicted diagrammatically in FIG. 4. The stop element 41 prevents a twist and/or displacement of the adjustment gear 11 arranged in the base position in the first rotation direction R.sub.2. Also, the torsion spring 31 is here configured for example such that the fixing element 25 turns in the first rotation direction R.sub.1 under defined pressure conditions in the housing 3. The torsion spring 31 is tensioned by this rotation, building up a return force.

(15) As furthermore shown in FIG. 4, the adjustment device 21 also has a stop element 43, which limits the twist of the fixing element 25 in the first rotation direction R.sub.1, and hence the displacement or twist of the adjustment gear 11 out of the base position, such that the adjustment gear 11 can only be displaced up to the maximum position.

(16) FIGS. 5 to 7 show a second embodiment of the gear pump according to the invention. The gear pump is here configured for example as an external gear pump 45. The external gear pump 45 has a plurality of, here for example two, drive gears with external toothing, here formed as spur gears 47, 49, to drive the external gear pump 45. Each of these spur gears 47, 49 is here for example intermeshed with a corresponding gear wheel, here also configured as a spur gear 51. The spur gears 51 are here for example fixed axially rotatably to a shaft 52. The shaft 52 is here for example fixed rigidly or immovably to the housing 3. Furthermore, the spur gears 47, 49, 51 are here configured identically or with identical design.

(17) As shown in FIG. 7, the fixing device 23 has a drive shaft 53 fixed rotatably to the housing 3 for driving the spur gears 47, 49. The spur gear 47 is here connected for example rotationally fixedly to the drive shaft 53. The spur gear 49 forming the adjustment gear is here fixed to the drive shaft 53 axially rotatably relative to the drive shaft 53. Furthermore, the two spur gears 47, 49 are here connected in a torque-transmissive fashion by a pretension element configured as a torsion spring 55. The torsion spring 55 is here arranged for example between the spur gears 47, 49 viewed in the axial direction x. The torsion spring 55 is tensioned by turning the adjustment gear 49 in a first rotation direction relative to the drive shaft 53 and hence also relative to the gear wheel 47. Also the torsion spring 55 is released by turning the adjustment gear 49 relative to the drive shaft 53 in a second rotation direction opposite to the first rotation direction.

LIST OF REFERENCE NUMERALS

(18) 1 Internal gear pump 3 Housing 5 Housing inlet 7 Housing outlet 9 Internally toothed spur gear 11 Externally toothed spur gear 13 Externally toothed spur gear 15 Tooth gap 19 Shaft 21 Adjustment device 23 Fixing device 25 Fixing element 27 Shaft 29 Shaft 31 Torsion spring 33 First end region 35 End region 37 Second end region 39 Fixing point 41 Stop element 43 Stop element 45 External gear pump 47 Spur gear 49 Spur gear 51 Spur gear 52 Shaft 53 Drive shaft 55 Torsion spring A.sub.1 First rotation axis A.sub.2 Second rotation axis R.sub.1 First rotation direction R.sub.2 Second rotation direction