Electric motor having a stator housing

Abstract

Electric motor having a stator housing, wherein: the stator housing has cooling fins; a holding plate is fastened to a first cooling fin of the stator housing and to a second cooling fin of the stator housing; the first cooling fin is mutually spaced from the second cooling fin; and an oil reservoir is fastened to the holding plate.

Description

[0001] Electric motor with stator housing

[0002] Description:

[0003] The invention relates to an electric motor with a stator housing.

[0004] It is known that an electric motor has a stator housing.

[0005] From US 10 826 347 B2, an electric motor is known as the closest prior art.

[0006] An electric motor is known from CN 1 11 874 094 A.

[0007] A drive is known from DE 10 2013 000 849 A1.

[0008] An electric motor with a fan is known from JP 2009-278 807 A.

[0009] A geared motor is known from DE 10 2021 002 635 A1.

[0010] The invention is therefore based on the object of developing the electric motor in a compact manner, i.e. achieving a high performance per unit volume.

[0011] According to the invention, the object is achieved in the electric motor according to the features specified in claim 1.

[0012] Important features of the invention in the electric motor with stator housing are that the stator housing has cooling fins, wherein a holding plate is fastened to a first cooling fin of the stator housing and to a second cooling fin of the stator housing, wherein the first cooling fin is spaced from the second cooling fin, wherein an oil container is fastened to the holding plate.

[0013] The advantage here is that the retaining plate, which acts as a bridge between the two cooling fins, is attached to the stator housing as an additional mass. This means that the electric motor's power loss is dissipated to the ambient air not only via the stator housing's cooling fins, but also via the retaining plate.

[0014] The oil reservoir allows compensation for the thermally induced volume change of the gearbox oil.

[0015] The oil reservoir attached to the mounting plate allows for heat dissipation from the oil reservoir—both through the cooling air flow and through contact with the mounting plate. The oil reservoir is preferably made of metal and thus forms a heat-conducting connection to the mounting plate.

[0016] The cooled oil in the oil reservoir can be supplied to the transmission, which can then transmit greater power within the same space. Overall, the entire electric motor achieves high power per unit volume. This further enhances the compactness of the electric motor.

[0017] In an advantageous embodiment, the retaining plate is arranged between the oil reservoir and the stator housing. The advantage here is that the retaining plate acts as an enlargement of the surfaces to be cooled.

[0018] In an advantageous embodiment, a first tab region of the retaining plate is connected to the first cooling fin, in particular by means of screws, and a further first tab region is connected to the second cooling fin, in particular by means of screws. Advantageously, the retaining plate is mechanically and thermally coupled to the stator housing. This enables improved heat dissipation to the environment.

[0019] In an advantageous embodiment, the respective first tab region has at least one circumferentially or tangentially directed continuous recess. This is advantageous because a simple fastening method for the retaining plate can be implemented. Although a person skilled in the art would normally avoid creating recesses in cooling fins, the attachment of the retaining plate increases the overall surface area for heat dissipation. Thus, the disadvantage caused by the recesses is more than compensated for.

[0020] In an advantageous embodiment, the first cooling fin has at least one circumferentially or tangentially directed continuous recess. This is advantageous because a simple fastening method for the retaining plate can be implemented. Although a person skilled in the art would typically avoid creating recesses in cooling fins, the attachment of the retaining plate increases the total surface area for heat dissipation. Thus, the disadvantage caused by the recesses is more than compensated for.

[0021] In an advantageous embodiment, the second cooling fin has at least one circumferentially or tangentially directed continuous recess, in particular wherein a first screw protrudes through the first tab region and the first cooling fin, and a second screw protrudes through the further first tab region and the second cooling fin. This is advantageous in that a simple fastening method for the retaining plate can be implemented. Although a person skilled in the art would normally avoid creating recesses in cooling fins, the attachment of the retaining plate increases the total surface area for heat dissipation. Thus, the disadvantage caused by the recesses is more than compensated for.

[0022] In an advantageous embodiment, the retaining plate is manufactured as a stamped and bent part made of sheet metal, with the respective first tab region adjacent to a preferably flat base region of the retaining part and angled relative to the base region. The advantage here is that the retaining plate is simple and cost-effective to manufacture.

[0023] In an advantageous embodiment, a second tab region of the holding part adjoins the preferably flat base region of the holding part and is angled relative to the base region, in particular, the second tab region is bent away from the base region, extending away from the stator housing. It is advantageous that the second tab region points away from the stator housing, whereas the first tab regions point toward the stator housing.

[0024] In an advantageous embodiment, the respective first and / or second tab region is each substantially flat, in particular, wherein the first tab regions are each bent from the base region toward the stator housing. This is advantageous in that simple manufacturing is enabled and surface contact of the respective cooling fins is possible.

[0025] In an advantageous embodiment, the oil reservoir has a connection area for a vent valve and a connection area for an adapter. Advantageously, the two connection areas are spaced apart from each other, allowing transmission oil to flow into or out of the oil reservoir via the adapter connection area, and allowing pressure equalization with the ambient air via the vent valve connection area. Preferably, the connection area for the vent valve is arranged above the connection area for the adapter in the direction of gravity.

[0026] In an advantageous embodiment, the axial direction is preferably aligned parallel to the vertical direction. It is advantageous that the axial direction is aligned parallel to the direction of gravity. The rotor shaft of the electric motor is therefore preferably aligned vertically.

[0027] In an advantageous embodiment, the connection area for the vent valve is located above the connection area for the adapter. This is advantageous because air accumulates above the oil in the oil reservoir, particularly because the oil reservoir contains both oil and air.

[0028] In an advantageous embodiment, a fan is connected to the rotor shaft of the electric motor in a rotationally fixed manner, with the air flow conveyed by the fan exiting between a fan cover of the electric motor and the stator housing and flowing at least partially along the retaining plate and / or the oil reservoir. This is advantageous because, during operation of the electric motor, the rotor shaft of the electric motor has a constant speed, which, when the transmission is designed as a reduction gear, rotates faster than any other shaft of the transmission. This allows for high fan output.

[0029] In an advantageous design, the airflow conveyed by the fan flows downwards in the direction of gravity. This is advantageous because the stator housing is located above the gearbox. The retaining plate, including the oil reservoir, is thus positioned above the gearbox. When the rotor shaft is at rest, a convective flow builds up, which flows upwards along the retaining plate and the cooling fins.

[0030] In an advantageous embodiment, the connection area for the vent valve protrudes through a recess in the second tab area, in particular, with a nut screwed onto the connection area for fastening the oil reservoir to the second tab area. This advantageously pressed the oil reservoir against the second tab area, thus transferring the heat to the retaining plate.

[0031] In an advantageous embodiment, the rotor shaft of the electric motor drives a gearbox whose interior is filled with oil. An oil line, in particular a pipe or hose, leads from the gearbox to the adapter, which is connected to the adapter connection area. This is advantageous because thermally induced volume changes in the oil can be compensated for by the oil reservoir. The oil line allows the oil in the interior of the gearbox to flow into the oil reservoir when it expands.

[0032] In an advantageous embodiment, the vent valve is connected to the connection area for the vent valve, in particular wherein the vent valve has a membrane, in particular a lipophobic membrane, which separates the ambient air from the transmission oil. This is advantageous because air pressure equalization occurs through the membrane without oil escaping into the environment.

[0033] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.

[0034] The invention will now be explained in more detail using schematic illustrations:

[0035] Figure 1 shows an oblique view of an area of ​​an electric motor according to the invention, wherein an oil container 4 is fastened to a stator housing of the electric motor by means of a retaining plate 2.

[0036] In Figure 2, the retaining plate 2 is shown in an oblique view.

[0037] Figure 3 shows the oil tank in an oblique view.

[0038] As shown in the figures, the stator housing has cooling fins 1 extending axially and projecting radially from the stator housing.

[0039] The axial direction is parallel to the rotational axis of the rotor shaft of the electric motor; the radial direction and the circumferential direction are each related to the rotational axis of the rotor shaft.

[0040] A first tab portion 21 is attached to a first of the cooling fins 1 of the stator housing by means of a screw, which extends through a recess in the first tab portion 21 and through a recess in the first cooling fin 1. The screw head presses the first tab portion 21 against the cooling fin 1.

[0041] A further first tab region 21 is fastened to a second of the cooling fins 1 of the stator housing by means of a further screw, which extends through a recess in the further first tab region 21 and through a recess in the further first cooling fin 1. The screw head of the screw presses the further first tab region 21 against the second cooling fin 1.

[0042] The two first tab regions 21 are spaced apart from one another and border on a base region 20 of the retaining plate 2 and are angled to the base region 20.

[0043] The base region 20 is preferably flat, in particular not curved. A second tab region 22 is spaced apart from the two first tab regions 21 and also borders the base region 20 and is angled relative to the base region 20.

[0044] The retaining plate 2 is manufactured as a stamped and bent part from sheet metal, wherein the retaining plate 2 together with the base region 20, the two first tab regions 21 and the second tab region 22 are designed in one piece, in particular in one part.

[0045] The first two tab regions 21 are angled, in particular bent, from the base region 20 toward the stator housing. The second tab region 22 is angled, in particular bent, away from the stator housing.

[0046] In this way, an oil reservoir 4 can be attached to the retaining plate 2. The oil reservoir has, on the one hand, a connection area 31 for an adapter 3, to which an oil line, in particular a pipe or hose, can be connected. The oil line leads to a transmission driven by the electric motor.

[0047] On the opposite side of the oil tank 4 in the axial direction, the oil tank 4 has a connection area 30 for a vent valve 5.

[0048] Preferably, the axial direction is parallel to the vertical direction.

[0049] Thus, the oil reservoir 4 is arranged above the transmission in the direction of gravity and functions as an oil expansion tank. As the temperature of the transmission increases, the oil in the transmission expands, and the oil level in the oil reservoir 4 rises. Above the oil level, there is air in the oil reservoir 4. The air pressure is equalized by the vent valve 5, which preferably has a semipermeable membrane and / or a lipophobic membrane. The membrane separates the interior of the oil reservoir 4 from the ambient air. This prevents oil, oil mist, or similar media containing oil droplets from penetrating the membrane and thus also the vent valve 5.

[0050] The retaining plate 2 is thus arranged between the oil reservoir 4 and the stator housing. Preferably, the first cooling fin 1 is freely accessible tangentially. Thus, there are no additional cooling fins that could impede access for operating the respective screw.

[0051] Preferably, the cooling fin of the stator housing that is closest to the first cooling fin 1 in the circumferential direction is oriented perpendicular to the first cooling fin 1. The circumferential direction points away from the second cooling fin 1, in particular the one that abuts the further first tab region 21.

[0052] The cooling fin of the stator housing that is closest to the second cooling fin 1 in the circumferential direction is aligned perpendicular to the second cooling fin 1. The circumferential direction points from the second cooling fin 1 to the first cooling fin 1.

[0053] In the circumferential direction between the second cooling fin 1 and the first cooling fin 1, a plurality of cooling fins of the stator housing are arranged, in particular wherein these are aligned almost parallel or substantially almost parallel.

[0054] Preferably, the oil tank 4 including the vent valve 5 does not protrude axially beyond the rest of the electric motor.

[0055] For fastening the oil tank 4 to the retaining plate, the connection area 30 is passed through a recess of the second tab area 22 and has an external thread area onto which a nut is screwed, which rests on the second tab area 22, which is thus clamped between the nut and the remaining oil tank 4.

[0056] The screws that press the retaining plate onto the respective cooling fin are each aligned tangentially.

[0057] The second tab area 22 is arranged above the first tab area 21.

[0058] Although the first and second cooling fins each have a continuous recess for the respective screws, efficient dissipation of waste heat is achieved through the first tab areas 21, which are pressed against the screw heads. This is because the retaining plate 2 is made of a metal sheet, in particular sheet steel, and the stator housing with its cooling fins 1 is made of a metal, in particular steel, cast steel, die-cast aluminum, or extruded aluminum.

[0059] On the side of the stator housing facing away from the gearbox in the axial direction, a fan is non-rotatably connected to the rotor shaft of the electric motor. This enables passive fan operation.

[0060] The air flow conveyed by the fan flows out between the stator housing and a fan cover along the cooling fins 1, so that part of the air flow flows between the stator housing and the retaining plate 2.

[0061] This not only improves the heat dissipation of the electric motor, but also improves the cooling of the oil reservoir 4. The cooled oil thus also contributes to the heat dissipation of the transmission. It is also important that the fan only drives an airflow that flows counter to the direction of gravity, particularly downwards, when the rotor shaft is rotating. However, when the rotor shaft is rotating, a high power loss also occurs in the transmission, which then leads to an increase in the temperature of the transmission oil.

[0062] When the rotor shaft is stationary and the oil is still hot, a convectively driven air flow moves upwards, i.e. opposite to the direction of gravity.

[0063] The direction of the cooling air flow is therefore reversed when the electric motor stops operating.

[0064] The first two tab areas 21 are aligned parallel to each other.

[0065] The second tab area 22 is aligned perpendicular to the two first tab areas 21.

[0066] Preferably, both the first two tab areas 21 and the second

[0067] The tab area 22 and the base area 20 are flat. The second tab area 22 is aligned perpendicular to the base area 20. The first two tab areas 21 are also aligned perpendicular to the base area 20.

[0068] In further embodiments according to the invention, additional tab regions are partially punched out on the base region 20 and bent toward the stator housing, so that at least a portion of the cooling air flow is directed by means of the additional tab regions through the recesses in the base region 20 created during the punching out of the additional tab regions to the oil reservoir 4. In this way, the cooling of the oil reservoir 4 is improved.

[0069] List of reference symbols

[0070] 1 Cooling fins of the stator housing 2 Retaining plate

[0071] 3 adapters

[0072] 4 oil containers

[0073] 5 vent valve

[0074] 20 Base area 21 First tab area

[0075] 22 second tab area

[0076] 23 Recess

[0077] 30 Connection area for vent valve 5

[0078] 31 Connection area for adapter 3

Claims

Patent claims:

1. Electric motor with stator housing, wherein the stator housing has cooling fins, characterized in that a holding plate is fastened to a first cooling fin of the stator housing and to a second cooling fin of the stator housing, wherein the first cooling fin is spaced from the second cooling fin, wherein an oil container is fastened to the holding plate, a first tab region of the holding plate is connected to the first cooling fin, in particular by means of screws, and a further first tab region is connected to the second cooling fin, in particular by means of screws.

2. Electric motor with stator housing, wherein the stator housing has cooling fins, characterized in that a holding plate is fastened to a first cooling fin of the stator housing and to a second cooling fin of the stator housing, wherein the first cooling fin is spaced from the second cooling fin, wherein a first tab region of the holding plate is connected to the first cooling fin and a further first tab region of the holding plate is connected to the second cooling fin, wherein an oil container is fastened to a second tab region of the holding plate.

3. Electric motor according to claim 1 or 2, characterized in that the retaining plate is arranged between the oil tank and the stator housing.

4. Electric motor according to one of the preceding claims, characterized in that a first tab region of the holding plate is connected to the first cooling fin, in particular by means of screws, and a further first tab region is connected to the second cooling fin, in particular by means of screws.

5. Electric motor according to one of the preceding claims, characterized in that the respective first tab region has at least one recess which is directed in the circumferential direction or tangentially and / or that the first cooling fin has at least one recess which is directed in the circumferential direction or tangentially and / or that the second cooling fin has at least one recess which is directed in the circumferential direction or tangentially, in particular wherein a first screw protrudes through the first tab region and the first cooling fin and a second screw protrudes through the further first tab region and the second cooling fin.

6. Electric motor according to one of the preceding claims, characterized in that the holding plate is manufactured as a stamped and bent part from sheet metal, wherein the respective first tab region adjoins a preferably flat base region of the holding part and is angled to the base region.

7. Electric motor according to one of the preceding claims, characterized in that a second tab region of the holding part adjoins the preferably flat base region of the holding part and is angled to the base region, in particular wherein the second tab region is bent away from the base region, starting from the stator housing.

8. Electric motor according to one of the preceding claims, characterized in that the respective first and / or second tab region is each substantially flat, in particular wherein the first tab regions are each bent from the base region towards the stator housing.

9. Electric motor according to one of the preceding claims, characterized in that the oil tank has a connection area for a vent valve and a connection area for an adapter.

10. Electric motor according to one of the preceding claims, characterized in that the axial direction is preferably aligned parallel to the vertical direction.

11. Electric motor according to one of the preceding claims, characterized in that the connection area for the vent valve is arranged above the connection area for the adapter.

12. Electric motor according to one of the preceding claims, characterized in that a fan is connected in a rotationally fixed manner to the rotor shaft of the electric motor, wherein the air flow conveyed by the fan exits between a fan cover of the electric motor and the stator housing and flows at least partially along the retaining plate and / or the oil tank.

13. Electric motor according to one of the preceding claims, characterized in that the air flow conveyed by the fan flows downwards in the direction of gravity, and / or that the connection area for the vent valve projects through a recess of the second tab area, in particular wherein a nut is screwed onto the connection area for fastening the oil container to the second tab area.

14. Electric motor according to one of the preceding claims, characterized in that the rotor shaft of the electric motor drives a gearbox, the interior of which is filled with oil, wherein an oil line, in particular a pipe or hose line, leads from the gearbox to the adapter, which is connected to the connection area for the adapter.

15. Electric motor according to one of the preceding claims, characterized in that the vent valve is connected to the connection area for the vent valve, in particular wherein the vent valve has a membrane, in particular a lipophobic membrane, wherein the membrane separates the ambient air from the oil of the transmission.

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