Electric machine with improved connection of an oil pump

Abstract

The invention relates to an electric machine (1, 1a), which comprises a stator housing (2, 2a) with an oil feed channel (3, 3a) arranged therein, a stator (7) arranged in the stator housing (2, 2a) and an oil pan (14, 14a) which is arranged under the stator housing (2, 2a), an oil discharge channel (15, 15a) being arranged in the oil pan. The electric machine (1, 1a) also comprises an oil pump (16) which is hydraulically connected on the intake side to the oil discharge channel (15, 15a) and on the pressure side to the oil feed channel (3, 3a). In a case a), a pump housing (17) of the oil pump (16) is fastened to the stator housing (2, 2a) and is not fastened to the oil pan (14, 14a), wherein only one or more seals (23) are arranged between the pump housing (17) and the oil pan (14, 14a). In a case b), a pump housing (17) of the oil pump (16) is fastened to the oil pan (14, 14a) and is not fastened to the stator housing (2, 2a), wherein only one or more seals (24) are arranged between the pump housing (17) and the stator housing (2, 2a). The invention also relates to a vehicle (25) having such an electric machine and to a method for producing such an electric machine (1, 1a).

Description

[0001] Electric machine with improved connection of an oil pump

[0002] TECHNICAL FIELD

[0003] The invention relates to an electric machine comprising a stator housing with an oil inflow channel arranged therein, a stator arranged in the stator housing, and an oil pan arranged beneath the stator housing with an oil outflow channel arranged therein. The electric machine further comprises an oil pump, which is hydraulically connected to the oil outflow channel on the suction side and to the oil inflow channel on the pressure side. The invention also relates to a vehicle having such an electric machine and a manufacturing method for such an electric machine.

[0004] STATE OF THE ART

[0005] Such an electric machine, such a vehicle, and such a manufacturing process are generally known from the prior art. The problem is that an unfavorable combination of component tolerances of the stator housing, oil pan, and oil pump in the assembled state of the electric machine can cause mechanical stresses that can negatively impact the operation or service life of the lubrication and cooling system. For example, leakage problems, cracks, or fatigue fractures can occur, which can even cause parts of the lubrication and cooling system to break off.

[0006] DISCLOSURE OF THE INVENTION

[0007] An object of the invention is therefore to provide an improved electric machine, an improved vehicle with an electric machine, and an improved manufacturing method for an electric machine. In particular, the stator housing, oil pan, and oil pump should be assembled in such a way that no excessive mechanical stresses arise between the components, which could negatively affect the operation or service life of the lubrication and cooling system.

[0008] The object of the invention is achieved with an electrical machine of the type mentioned at the outset, in which a) a pump housing of the oil pump is fastened to the stator housing and is free from any fastening to the oil pan, wherein only one or more seals are arranged between the pump housing and the oil pan, or b) a pump housing of the oil pump is fastened to the oil pan and is free from any fastening to the stator housing, wherein only one or more seals are arranged between the pump housing and the stator housing.

[0009] Furthermore, the object of the invention is achieved with a vehicle having such an electric machine which is provided for driving the vehicle.

[0010] Finally, the object of the invention is achieved by a method for producing an electrical machine, which comprises the following steps:

[0011] Arranging an oil pan with an oil drainage channel arranged therein under a stator housing, which comprises an oil inflow channel arranged therein (and possibly already a stator arranged in the stator housing), hydraulically connecting an oil pump on the suction side to the oil drainage channel and on the pressure side to the oil inflow channel, wherein a) a pump housing of the oil pump is fastened to the stator housing and is kept free from any attachment to the oil pan and wherein only one or more seals are arranged between the pump housing and the oil pan, or b) a pump housing of the oil pump is fastened to the oil pan and is kept free from any attachment to the stator housing and wherein only one or more seals are arranged between the pump housing and the stator housing.The proposed solution allows for unavoidable component tolerances of the stator housing, oil pan, and oil pump to be well compensated without creating mechanical stresses that could negatively impact the operation or service life of the lubrication and cooling system. This prevents leakage problems, cracks, and fatigue fractures.

[0012] In particular, the oil pan can be attached to the stator housing, for example by screwing. The oil pan and the stator housing can then be part of a machine housing of the electric machine. In addition, the pump housing, which can in particular be made of plastic, can be screwed to the stator housing in case a) and to the oil pan in case b). This creates a permanent but detachable connection between the components. In one design variant of the electric machine, the pump housing can be directly attached to the stator housing in case a) and directly to the oil pan in case b). It is also conceivable, however, that an intermediate part is provided between the pump housing and the stator housing, for example an adapter, in order to be able to use different types of oil pumps.

[0013] In an advantageous design variant of the electric machine, the pump housing is free from contact with the oil pan in case a) and free from contact with the stator housing in case b). In other words, in case a), a distance can be provided between a suction port of the oil pump and an oil drain channel of the oil pan. This means that in this case the oil drain channel of the oil pan does not touch the suction port of the oil pump either radially or axially. In case b), on the other hand, a distance can be provided between a pressure port of the oil pump and an oil inflow channel of the stator housing. This means that in this case the oil inflow channel of the stator housing does not touch the pressure port of the oil pump either radially or axially. The proposed solution allows tolerances to be compensated even better without creating mechanical stresses that could negatively affect the operation or service life of the lubrication and cooling system.It is also conceivable that in case a) only a single seal is provided between the pump housing and the oil pan, or in case b) only a single seal is provided between the pump housing and the stator housing. In particular, the seal can be designed as an O-ring seal or a flat seal. An O-ring seal, in particular, enables a sealing effect even with comparatively large component tolerances between the stator housing, oil pan, and oil pump.

[0014] SHORT DESCRIPTION OF THE CHARACTERS

[0015] Embodiments of the invention are illustrated by way of example in the accompanying schematic figures. They show:

[0016] Fig. 1 shows a half section through an exemplary electrical machine;

[0017] Fig. 2 is an exploded view of another electrical machine;

[0018] Fig. 3 is a side view of the electrical machine from Fig. 2, viewed diagonally from the front;

[0019] Fig. 4 a detailed view of the electrical machine from Fig. 2 and

[0020] Fig. 5 shows an exemplary vehicle with an electric machine of the proposed type.

[0021] DETAILED DESCRIPTION OF THE INVENTION

[0022] By way of introduction, it should be noted that identical parts in the different embodiments are provided with the same reference symbols or component designations, possibly with different indices. The disclosure of a component contained in the description can be applied analogously to another component with the same reference symbol or component designation. Furthermore, the positional information chosen in the description, such as "top," "bottom," "rear," "front," "side," and so on, refers to the directly described and illustrated figure and, in the event of a change in position, is to be applied analogously to the new position.

[0023] Fig. 1 shows a half-section through an exemplary electrical machine 1. The electrical machine 1 comprises a stator housing 2 with an oil inflow channel 3 arranged therein, a first bearing plate 4, and a second bearing plate 5. The stator housing 2, the first bearing plate 4, and the second bearing plate 5 together form the machine housing 6 or are at least part thereof. Arranged in the stator housing 2 is a stator 7, which comprises a stator laminated core 8 with stator windings 9 arranged therein. Furthermore, the electrical machine 1 comprises a rotor shaft 10 with a rotor 11 arranged thereon, which comprises a rotor laminated core 12 with magnets or rotor windings arranged therein (not shown) and which is rotatably mounted about a rotation axis A by means of (rolling) bearings 13a, 13b. The bearing 13a is arranged in the first bearing plate 4, the second bearing 13b in the second bearing plate 5.An oil pan 14 with an oil drainage channel 15 arranged therein is arranged beneath the stator housing 2. Specifically, the oil pan 14 can be attached, in particular screwed, to the stator housing 2. Finally, the electric machine 1 comprises an oil pump (not shown in Fig. 1), which is hydraulically connected on the suction side to the oil drainage channel 15 and on the pressure side to the oil inflow channel 3.

[0024] 2 to 4 show a somewhat more detailed example of a further electrical machine 1a, wherein Fig. 2 is an exploded view of the electrical machine 1a from below, Fig. 3 is a side view, in particular of the machine housing 6a, from the front, and Fig. 4 is a detailed view of the electrical machine 1a in partial section. The electrical machine 1a comprises an oil pump 16, which is hydraulically connected on the suction side to the oil discharge channel 15a and on the pressure side to the oil inflow channel 3a. For this purpose, a suction nozzle 18 arranged on the pump housing 17 of the oil pump 16 is connected to the oil discharge channel 15a, and a pressure nozzle 19 arranged on the pump housing 17 is connected to the oil inflow channel 3a. The direction of flow of the oil into and out of the oil pump 16 is symbolized by arrows in Figs. 2 to 4. The pump housing 17 can, for example, be made of plastic.

[0025] In the specific case illustrated, the pump housing 17 of the oil pump 16 is fastened to the stator housing 2a. For example, the pump housing 17 can rest directly on the stator housing 2a, as is the case in the example illustrated in Figs. 2 to 4. Specifically, the pump housing 17 rests against a flange 20 of the stator housing 2a and is screwed there to the stator housing 2a. For this purpose, fastening holes 21 are provided in the flange 20, into which screws can be inserted. However, it is also conceivable that an intermediate part is provided between the pump housing 17 and the stator housing 2a, for example an adapter, in order to be able to use different types of oil pumps 16.

[0026] The oil inlet channel 3a is guided in the stator housing 2a to a support surface 22 for an oil cooler, which is not shown in Figs. 2 to 4. Arrows symbolize the flow direction of the oil from the stator housing 2a into the oil cooler and from there back into the stator housing 2a, where it is internally directed to parts of the electrical machine 1a for lubrication and cooling. For example, it can be sprayed onto the stator windings 9 for cooling and / or directed to the bearings 13a, 13b for lubrication. The arrangement of an oil cooler directly on the stator housing 2a is not mandatory; it can also be arranged elsewhere (see also Fig. 5).

[0027] Only one or more seals 23 are arranged between the pump housing 17 and the oil pan 14a. In the specific case illustrated, only a single seal 23 is provided between the pump housing 17 and the oil pan 14a, which is designed here as an O-ring seal. However, it is also conceivable, for example, that multiple seals are provided. It is also conceivable that the seal 23 is designed as a flat seal.

[0028] A seal 24 is also arranged between the pump housing 17 and the stator housing 2a, to which the same applies as described above for seal 23. This seal is designed as an O-ring seal here, but it could also be a flat seal. It is also conceivable that multiple seals 24 are provided.

[0029] The pump housing 17 is, in particular, (completely) free from contact with the oil pan 14a, as shown in Fig. 4. Specifically, there is a distance G between the suction port 18 of the pump housing 17 and the oil drain channel 15a of the oil pan 14a. This means that, in the example shown, the oil drain channel 15a of the oil pan 14a does not touch the suction port 18 of the oil pump 16 either radially or axially. The proposed solution allows tolerances to be compensated particularly well, so that no mechanical stresses arise that could negatively affect the operation or service life of the lubrication and cooling system. The O-ring 23 used enables the sealing effect even with comparatively large tolerances.

[0030] In the example shown, the pump housing 17 of the oil pump 16 is fastened to the stator housing 2a and is free from any attachment to the oil pan 14a. However, the reverse case is also conceivable, namely that the pump housing 17 is fastened to the oil pan 14a and is free from any attachment to the stator housing 2. The pump housing 17 can in turn be (completely) free of contact with the stator housing 2a and, in particular, can rest directly on the oil pan 14a and be screwed to it. The advantages already mentioned apply analogously. In this case, too, the proposed solution can compensate for tolerances without creating mechanical stresses that could negatively affect the operation or service life of the lubrication and cooling system. The O-ring 24 enables the sealing effect even with comparatively large tolerances.

[0031] A method for manufacturing an electrical machine can now comprise the following steps:

[0032] Arranging an oil pan 14, 14a with an oil drainage channel 15, 15a arranged therein under a stator housing 2, 2a, which comprises an oil inflow channel 3, 3a arranged therein (and possibly already a stator 7 arranged in the stator housing 2, 2a), hydraulically connecting an oil pump 16 on the suction side to the oil drainage channel 15, 15a and on the pressure side to the oil inflow channel 3, 3a, wherein a) a pump housing 17 of the oil pump 16 is fastened to the stator housing 2, 2a and is kept free from attachment to the oil pan 14, 14a and wherein only one or more seals 23 are arranged between the pump housing 17 and the oil pan 14, 14a, or b) a pump housing 17 of the oil pump 16 is fastened to the oil pan 14, 14a and is kept free from attachment to the stator housing 2, 2a and wherein only one or more seals 24 are arranged between the pump housing 17 and the stator housing 2, 2a.

[0033] Finally, Fig. 5 shows the electric machine 1 installed in a vehicle 25. The vehicle 25 has two axles, one of which is driven. Specifically, the electric machine 1 is connected to the semi-axles 27 of the rear axle. Finally, the driven wheels 28 are mounted on the semi-axles 27. The vehicle 25 is driven at least partially or temporarily by the electric machine 1. This means that the electric machine 1 can serve to drive the vehicle 25 alone or, for example, be provided in conjunction with an internal combustion engine (hybrid drive).

[0034] The vehicle 25 also includes an oil circuit, into which the electric machine 1, the oil pump 16, and an oil cooler 29 are integrated. The oil cooler 29 is arranged at a distance from the electric machine 1, with the oil flow partially passing through the stator housing 2, 2a. Of course, the vehicle 25 could also be constructed such that the oil cooler 29 is mounted directly on the electric machine 1 (see also the support surface 22 for the oil cooler in Fig. 3).

[0035] Finally, it is noted that the scope of protection is determined by the patent claims. However, the description and drawings must be used to interpret the claims. The features contained in the figures can be interchanged and combined with one another as desired. In particular, it is also noted that the devices depicted may in reality comprise more or fewer components than shown. In some cases, the depicted devices or their components may also be shown not to scale and / or enlarged and / or reduced in size.

[0036] List of reference symbols

[0037] 1 , 1 a electrical machine

[0038] 2, 2a Stator housing

[0039] 3, 3a Oil inflow channel

[0040] 4 first bearing plate

[0041] 5 second bearing plate

[0042] 6, 6a Machine housing

[0043] 7 Stator

[0044] 8 stator lamination pack

[0045] 9 Stator winding

[0046] 10 Rotor shaft

[0047] 11 Rotor

[0048] 12 rotor lamination pack

[0049] 13a, 13b (rolling) bearings

[0050] 14, 14a oil pan

[0051] 15, 15a Oil drainage channel

[0052] 16 Oil pump

[0053] 17 Pump housing

[0054] 18 suction nozzles

[0055] 19 pressure nozzles

[0056] 20 flange

[0057] 21 Mounting hole

[0058] 22 Support surface for oil cooler

[0059] 23 Seal (suction side)

[0060] 24 Seal (pressure side)

[0061] 25 vehicles

[0062] 26 gearboxes

[0063] 27 semi-axle

[0064] 28 wheels

[0065] 29 Oil cooler

[0066] A axis of rotation

[0067] G Distance

Claims

Patent claims 1. An electrical machine (1, 1a), comprising a stator housing (2, 2a) with an oil inflow channel (3, 3a) arranged therein, a stator (7) arranged in the stator housing (2, 2a), an oil pan (14, 14a) arranged below the stator housing (2, 2a) with an oil outflow channel (15, 15a) arranged therein, and an oil pump (16) which is hydraulically connected on the suction side to the oil outflow channel (15, 15a) and on the pressure side to the oil inflow channel (3, 3a), characterized in that a) a pump housing (17) of the oil pump (16) is fastened to the stator housing (2, 2a) and is free from any attachment to the oil pan (14, 14a), wherein between the pump housing (17) and the oil pan (14, 14a) only one or more seals (23) are arranged, or b) a pump housing (17) of the oil pump (16) is fastened to the oil pan (14, 14a) and is free from attachment to the stator housing (2, 2a), wherein between the pump housing (17) and the stator housing (2,2a) only one or more seals (24) are arranged., 2. Electrical machine (1, 1a) according to claim 1, characterized in that the pump housing (17) is free from contact with the oil pan (14, 14a) in case a) and free from contact with the stator housing (2, 2a) in case b).

3. Electrical machine (1, 1a) according to claim 1 or 2, characterized in that in case a) only a single seal (23) is provided between the pump housing (17) and the oil pan (14, 14a) or in case b) only a single seal (24) is provided between the pump housing (17) and the stator housing (2, 2a).

4. Electrical machine (1, 1a) according to claim 3, characterized in that the seal (23, 24) is designed as an O-ring seal or flat seal.

5. Electrical machine (1, 1a) according to one of claims 1 to 4, characterized in that the pump housing (17) in case a) lies directly on the stator housing (2, 2a) and in case b) lies directly on the oil pan (14, 14a).

6. Electrical machine (1, 1a) according to one of claims 1 to 5, characterized in that the pump housing (17) is screwed to the stator housing (2, 2a) in case a) and to the oil pan (14, 14a) in case b).

7. Electrical machine (1, 1a) according to one of claims 1 to 6, characterized in that the oil pan (14, 14a) is fastened to the stator housing (2, 2a).

8. Vehicle (25) with an electric machine (1) according to one of claims 1 to 7, which is provided for driving the vehicle (25).

9. A method for producing an electrical machine (1, 1a), comprising the steps Arranging an oil pan (14, 14a) with an oil drainage channel (15, 15a) arranged therein under a stator housing (2, 2a), which comprises an oil inflow channel (3, 3a) arranged therein, hydraulically connecting an oil pump (16) on the suction side to the oil drainage channel (15, 15a) and on the pressure side to the oil inflow channel (3, 3a), wherein a) a pump housing (17) of the oil pump (16) is fastened to the stator housing (2, 2a) and is kept free from attachment to the oil pan (14, 14a), and wherein only one or more seals (23) are arranged between the pump housing (17) and the oil pan (14, 14a), or b) a pump housing (17) of the oil pump (16) is fastened to the oil pan (14, 14a) and is kept free from attachment to the stator housing (2, 2a) and wherein only one or more seals (24) are arranged between the pump housing (17) and the stator housing (2, 2a).

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