Electric axle drive for a vehicle with an electric machine with a stator

Abstract

An electric axle drive for a vehicle (1) having an electric machine with a stator (3) is proposed, wherein the stator (3) is assigned to a first rotor (4) for driving a first vehicle wheel (5) and to a second rotor (6) for driving a second vehicle wheel (7), wherein the stator (3) has at least one tubular laminated core (8, 9) with an axially extending winding (10), and wherein the first rotor (4) and the second rotor (6) are arranged axially one behind the other coaxially in the interior of the laminated core (8, 9). Furthermore, a vehicle (1) with an electric axle drive is proposed.

Description

[0001] The present invention relates to an electric axle drive for a vehicle with an electric machine for driving vehicle wheels of the vehicle.

[0002] Electric axle drives for vehicles are well known in automotive engineering. To independently drive the vehicle's wheels, the axle drive has two electric motors connected to one of the vehicle wheels directly or via a transmission. The two electric motors can drive the vehicle wheels independently of each other. The two electric motors required result in a considerable amount of installation space.

[0003] The object of the present invention is to propose an electric axle drive and a vehicle with an electric axle drive in which an independent drive of the vehicle wheels is realized in a particularly space-saving manner.

[0004] This object is achieved according to the invention by the features of patent claims 1 and 11. Advantageous and claimed developments emerge from the subclaims and the description as well as the drawings.

[0005] Thus, an electric axle drive for a vehicle with an electric machine having a stator is proposed, wherein the stator is associated with a first rotor for driving a first vehicle wheel and a second rotor for driving a second vehicle wheel, wherein the stator has at least one tubular laminated core or the like with an axially extending winding, and wherein the first rotor and the second rotor are arranged axially one behind the other coaxially in the interior of the laminated core.

[0006] In this way, an electric axle drive is proposed which advantageously provides only one electric machine with a stator with only one winding, to which two rotors are assigned for the independent or individual drive of the vehicle's wheels. This results in a significantly smaller installation space requirement for the proposed axle drive, while at the same time reducing manufacturing costs. Because the stator has only one continuous winding, only two winding heads are required instead of four. This results in axial installation space savings due to the smaller number of winding heads and also due to significantly lower requirements for required clearance and creepage distances.The term clearance refers to the shortest distance between two electrical conductors through the air, while a creepage distance refers to a short circuit between two conductors on the surface of the insulating material when the effective voltage is exceeded.

[0007] In order to ensure adequate support for the shafts of the rotors of the electric machine in the space-saving arrangement of the proposed electric axle drive, a first embodiment variant can, for example, provide for the shafts of the first rotor and the second rotor to extend into each other at least in sections and be mutually supported. The quasi-radially arranged and supported rotors result, on the one hand, in axial space savings and, on the other hand, in the necessary support for the bearing forces occurring in the proposed axle drive.

[0008] Furthermore, within the scope of a further embodiment of the present invention, the electric axle drive can be provided with a first laminated core and a second laminated core, wherein the first laminated core and the second laminated core are arranged axially one behind the other and connected to one another via an intermediate section. In this way, the necessary axial distance between the rotors is used in a space-saving manner as an intermediate section, on the one hand to guide and hold the lines or wires or pins of the winding and, on the other hand, to support bearing forces of the mutually facing shaft ends of the rotors. The intermediate section can preferably be plate-shaped, disc-shaped, or designed as any desired shaped part.

[0009] The intermediate section can be made of any material. However, it is particularly advantageous to use non-conductive materials, such as fiberglass or similar, which are not only more cost-effective but also more environmentally friendly.

[0010] The support of bearing forces of the facing shaft ends of the rotors can be achieved in various ways, which, on the one hand, enable additional space savings and / or cost savings by integrating additional functions into the intermediate section. For example, this can be achieved by enabling additional fastening functions or the like.

[0011] A particularly advantageous additional function can be realized by providing the intermediate section with a cooling circuit for cooling the electric machine.

[0012] The object underlying the invention is also achieved by a vehicle with the electric axle drive described above. This results in the advantages already described and others.

[0013] The invention is further explained below with reference to the drawings.

[0014] They show: Fig. 1 is a schematic view of a first embodiment of an electric axle drive according to the invention with an electric machine having a stator with a laminated core and two rotors for independently driving the vehicle wheels of a vehicle; Fig. 2 a schematic view of a second embodiment of the electric axle drive with two laminated cores connected to one another via an intermediate section; Fig. 3 a schematic view of the axle drive according to Fig. 2 with a plate-shaped design of the intermediate section; Fig. 4 a schematic view of the axle drive according to Fig. 2 with an alternative plate-shaped design of the intermediate section; Fig. 5 a schematic view of the axle drive according to Fig. 2 with the intermediate section having a cooling channel; Fig. 6 a schematic view of the axle drive according to Fig. 2 with two axially adjacent bearings of the mutually facing shaft ends of the rotors; Fig. 7 a schematic view of the axle drive according to Fig. 2 with two radially nested bearings of the facing shaft ends of the rotors.

[0015] In the Fig. 1 to 7, various embodiments and designs of an electric axle drive according to the invention are shown by way of example, wherein in Fig. 1 the electric axle drive is shown on a vehicle 1 which is only indicated schematically.

[0016] The electric axle drive comprises only one electric machine with only one stator 3 in a housing 2, wherein the stator 3 is assigned to a first rotor 4 for driving a first vehicle wheel 5 and a second rotor 6 for driving a second vehicle wheel 7. The stator 3 has at least one approximately tubular laminated core 8, 9 with an axially extending winding 10, wherein the first rotor 4 and the second rotor 6 are arranged axially one behind the other coaxially inside the tubular laminated core 8, 9.

[0017] With the proposed axle drive, the vehicle wheels 5, 7 are driven independently of each other by the associated rotors 4, 6. For example, it is conceivable that the shafts of the rotors 4, 6 are connected to the respective vehicle wheels 5, 7 via a transmission.

[0018] Because only one winding 10 with only two winding heads is used in the proposed axle drive in contrast to known axle drives, axial installation space can be saved, as shown for example by arrows in Fig. 2, Fig. 6 and Fig. 7 is indicated.

[0019] In Fig. 1 shows a first exemplary embodiment of the axle drive according to the invention, in which the shafts of the first rotor 4 and the second rotor 6 extend into one another at least in sections and are mutually supported, wherein the shafts of the rotors 4, 6 have different diameters. For this purpose, it is provided that a shaft end section 11 of the first rotor 4 is arranged in a hollow shaft end section 12 of the second rotor 6 and is supported in the hollow shaft end section 12 of the second rotor 6 via at least one bearing 13. Furthermore, the first rotor 4 is supported on the housing side at the other shaft end via a further bearing 15. The hollow shaft end section 12 of the second rotor 6 is supported on the housing side via at least one bearing 14. This results in a particularly space-saving arrangement, since the rotors 4, 6 can be positioned directly axially next to one another, since bearings in this area can be dispensed with.Since the rotors 4, 6 have only small differential speeds, if any, such a bearing arrangement is easily possible.

[0020] In Fig. Figure 2 shows a second embodiment of the axle drive according to the invention, in which a first laminated core 8 and a second laminated core 9 are provided, wherein the first laminated core 8 and the second laminated core 9 are arranged axially one behind the other and are connected to one another via an intermediate section 16, for example a plate-shaped one. The intermediate section 16 can be made of a non-conductive material. The intermediate section 16 can have the external shape of the stator 3 or the laminated cores 8, 9. The grooves or channels for the conductors of the winding 10 are introduced into the intermediate section 16 so that the conductors of the winding 10 can be wound through the intermediate section. Furthermore, two bearing shells or the like are introduced inside the intermediate section 16 so that the two rotor shafts 4, 6 can be mounted accordingly in the intermediate section.

[0021] In Fig. Figure 3 shows an alternative embodiment based on the second exemplary embodiment of the axle drive, in which the intermediate plate or intermediate section 16 is designed with a larger diameter than the laminated cores 8, 9, so that, for example, brackets or the like can be attached to the intermediate section 16, to which other components or even the stator 3 can be secured in the housing 2. It is also possible for the intermediate section 16 to be designed as a housing wall of the electrical machine.

[0022] In Fig. Figure 4 shows an alternative embodiment based on the second exemplary embodiment of the axle drive, in which the intermediate section 16 is smaller in diameter than the laminated cores 8, 9. The intermediate section 16 can have a circular, but also non-circular, or similar shape. This allows for connections to be made at specific locations, for example, to the housing 2.

[0023] In Fig. 5 shows a further alternative embodiment based on the second exemplary embodiment of the axle drive, in which the intermediate section 16 enables a cooling function in that the intermediate section 16 accommodates at least one cooling circuit 17 for cooling. In this embodiment, the intermediate section can be designed as a molded part which partially encloses the laminated cores 8, 9, so that cooling channels for coolant liquid can be integrated as a cooling circuit 17. The coolant can be guided through the intermediate section 16 into channels, for example, of the laminated cores 8, 9. Furthermore, it is conceivable that the intermediate section 16 also accommodates signal lines for sensors or the like. In this way, for example, temperature sensors can be mounted in the laminated core 8, 9 or between the rotors 4, 6. The intermediate section 16 can guide the lines or even contain the sensors.

[0024] In Fig. 6 shows a bearing design based on the second embodiment of the axle drive, in which the intermediate section 16 forms a bearing point for the mutually facing shaft ends of the first rotor 4 and the second rotor 6, wherein the bearing point comprises two axially adjacent layers 18, 19 which support the associated shaft ends of the rotors 4, 6 in the intermediate section 16.

[0025] In Fig. 7 shows a further bearing design based on the second embodiment of the axle drive, in which the bearing point in the intermediate section 16 comprises two radially nested bearings 20, 21. In this way, the two rotor bearings 20, 21 are designed one inside the other, so that further axial installation space can be saved, as indicated by arrows in Fig.7. A further advantage of this bearing arrangement is that, at the same speed of the rotors 4, 6, only the outer bearing 21 rotates and thus the losses are halved. Reference symbol 1 vehicle 2 housings 3 Stator 4 first rotor or rotor shaft 5 vehicle wheel 6 second rotor or rotor shaft 7 vehicle wheel 8 first sheet package 9 second sheet package 10 windings 11 Shaft end section of the first rotor 12 Hollow shaft end section of the second rotor 13 camps 14 camps 15 warehouses 16 Intermediate section or intermediate plate 17 Cooling circuit 18 camps 19 camps 20 warehouses 21 warehouses

Claims

[1] Electric axle drive for a vehicle (1) with an electric machine with a stator (3), wherein the stator (3) is assigned to a first rotor (4) for driving a first vehicle wheel (5) and a second rotor (6) for driving a second vehicle wheel (7), wherein the stator (3) has at least one tubular laminated core (8, 9) with an axially extending winding (10), and wherein the first rotor (4) and the second rotor (6) are arranged axially one behind the other coaxially in the interior of the laminated core (8, 9). [2] Electric axle drive according to claim 1, characterized by that the shafts of the first rotor (4) and the second rotor (6) extend into each other at least in sections and are mutually supported. [3] Electric axle drive according to claim 2, characterized bythat a shaft end section (11) of the first rotor (4) is arranged in a hollow shaft end section (12) of the second rotor (6) and is mounted in the hollow shaft end section (12) of the second rotor (6) via at least one bearing (13), wherein the hollow shaft end section (12) of the second rotor (6) is mounted on the housing side via at least one bearing (14). [4] Electric axle drive according to claim 1, characterized by that a first laminated core (8) and a second laminated core (9) are provided, wherein the first laminated core (8) and the second laminated core (9) are arranged axially one behind the other and are connected to one another via an intermediate section (16). [5] Electric axle drive according to claim 4, characterized by that the intermediate section (16) is made of a non-conductive material. [6] Electric axle drive according to claim 4 or 5, characterized bythat the intermediate section (16) forms at least one bearing point for the mutually facing shaft ends of the first rotor (4) and the second rotor (6). [7] Electric axle drive according to claim 6, characterized by that the bearing point comprises two bearings (18, 19) arranged axially next to one another. [8] Electric axle drive according to claim 6, characterized by that the bearing point comprises two radially nested bearings (20, 21). [9] Electric axle drive according to one of claims 4 to 8, characterized by that the intermediate section (16) is designed as a housing wall of the electrical machine. [10] Electric axle drive according to one of claims 4 to 9, characterized by that the intermediate section (16) has a cooling circuit (17) for cooling. [11] Vehicle (1) with at least one electric axle drive according to one of the preceding claims.

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