Patent Application
20240229790
The invention relates to a gear pump having a pump housing, in particular to a multiple-flow gear pump.
Gear pumps are used, for example, for dry sump lubrication of a powertrain in a motor vehicle. For example, a gear pump conveys lubricating oil out of a lubricating oil container to the lubrication sites of a drive machine of a gearbox.
A disadvantage of known gear pumps is that they are sometimes labour-intensive to assemble. In particular the mounting of the gearwheels of the pump and mounting of a rotor of the gear pumps is sometimes complex.
It is therefore an object of the invention to specify a gear pump which can be assembled particularly simply.
According to the invention, this object is achieved by a 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.
The gear pump according to the invention has the advantage that an axial mounting of the rotor is achieved in a particularly simple manner without additional bearing elements. In particular, the drive gearwheel, which is present anyway, is used for axial mounting, which also contributes to a compact construction of the gear pump.
The axial mounting of the rotor by means of the drive gearwheel is achieved, for example, in that an axial movement of the drive gearwheel is limited, in particular by walls of the pump housing.
For example, the drive gearwheel bears axially against a wall of the pump housing by at least one end face.
The at least one drive gearwheel is for example 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. In this way, the drive gearwheel can be axially positioned particularly precisely. The assembly of the gear pump is simplified further by injection-moulding the drive gearwheel onto the drive shaft, since fewer manual assembly steps are required.
According to one aspect, 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.
Because a second drive gearwheel is mounted on the drive shaft, the gear pump has a two-layer design. This means that two axially adjacent drive gearwheels can be driven with the same drive shaft.
Because the intermediate element is shorter than the second drive gearwheel as viewed in the axial direction, positional tolerances can be compensated. In particular, the second drive gearwheel can be positioned flexibly a little in the axial direction without the intermediate element protruding beyond the second drive gearwheel.
The second drive gearwheel can be mounted on the intermediate element with play. A sliding guide is realized thereby between the second drive gearwheel and the intermediate element, as a result of which tolerance compensation is achieved particularly simply and in particular is produced automatically when the gear pump is assembled.
The axial movement of the second drive gearwheel can likewise be limited, in particular by walls of the pump housing.
The intermediate element is pressed or injection-moulded onto the drive shaft, for example. This likewise contributes to a simple assembly of the gear pump.
In each case, two driven gearwheels can be in engagement with each of the drive gearwheels. In this way, a four-flow gear pump is realized; that is, four separate fluid flows can be sucked in by the gear pump and conveyed to different sites in a powertrain. In particular, a four-flow gear pump is particularly suitable for cooling the total of four winding ends of two main motors of an electric vehicle.
The driven gearwheels preferably sit on a shaft with play. This means that the driven gearwheels run freely with the drive gearwheels.
According to a further embodiment, 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.
In this context, “single-layered” means that all the gearwheels lie in one plane. With this construction, a design with a particularly low height and reduced length in comparison with a two-layer design can be achieved.
With the aforementioned arrangement of the gearwheels, a four-flow design is likewise achieved.
The driven gearwheels which are in engagement with the drive gearwheel each form a drive gearwheel for the further gearwheels.
In the single-layered design too, the driven gearwheels preferably each sit on a shaft with play.
For example, 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. When the pump housing is mounted on an oil sump, oil can be sucked out of the oil sump directly into the pump housing in this manner. In particular, the pump housing can be placed directly onto the oil sump.
In a multiple-flow design, in particular all the inlet openings are situated on the underside of the pump housing.
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. In this way, oil can be conducted into the motor housing to cool the drive motor.
The drive motor is preferably an electric motor; that is, the drive motor comprises a rotor and a stator. The gear pump can be operated particularly efficiently thereby.
Further advantages and features can be found in the following description and the appended drawings. In the drawings:
The gear pump 10 comprises a pump housing 12 and a motor housing 14.
In
The pump housing 12, the motor housing 14 and the oil sump 16 are preferably manufactured from plastic.
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
The drive motor 20 is preferably potted in the motor housing 14.
The drive motor 20 drives a drive shaft 22, which extends into the pump housing 12.
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.
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.
The two drive gearwheels 26, 28 are axially spaced from one another.
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.
For example, the first drive gearwheel 26 is pressed or injection-moulded onto the drive shaft 22.
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.
An intermediate element 30 is arranged radially between the second drive gearwheel 28 and the drive shaft 22.
The intermediate element 30 is in torque-transmitting engagement both with the drive shaft 22 and with the second drive gearwheel 28.
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.
The second drive gearwheel 28 is mounted on the intermediate element 30 with play, as a result of which a sliding guide is realized.
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.
However, the drive gearwheels 26, 28 have a small axial play in the pump housing 12 to compensate manufacturing tolerances and thermal expansions.
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.
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.
As can be seen both in
Since the gearwheels 26, 28, 38, 40, 42, 44 are arranged in two layers, as can be seen in
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.
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.
The intermediate element 30 is pressed or injection-moulded on the drive shaft 22.
The oil intake ducts 50 run in the pump housing 12 and are formed by corresponding cut-outs in the pump housing 12.
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.
In the perspective view in
When the gear pump 10 is placed onto the oil sump 16, oil can be sucked in directly out of the oil sump 16.
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.
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.
A single-layered design is realized in the gear pump 10 of
As a result, the construction of the gear pump 10 is particularly flat.
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
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
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
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.
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.
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.
In the embodiment according to
| Number | Date | Country | Kind |
|---|---|---|---|
| 102022128264.3 | Oct 2022 | DE | national |
| Number | Date | Country | |
|---|---|---|---|
| 20240133377 A1 | Apr 2024 | US |
