Electric machine for powering a motor vehicle and motor vehicle with an electric machine

Abstract

The invention relates to an electric machine (100) for driving a motor vehicle (K), comprising a stator (10) which has a stator support element (20) and stator teeth (50, 60, 70) connected to the stator support element (20). The stator support element (20) is formed, at least partially, from a first soft magnetic material. A further aspect of the invention relates to a motor vehicle (K) with an electric machine (100) designed as the drive machine of the motor vehicle.

Description

[0001] The invention relates to an electric machine for driving a motor vehicle, comprising a stator having a stator support element and stator teeth connected to the stator support element. A further aspect of the invention relates to a motor vehicle having an electric machine designed as the drive motor of the motor vehicle.

[0002] In an operational electrical machine, for example, a stator has respective wire windings that are received on the stator teeth. For example, EP 2 770 616 A1 discloses an electrical machine that has a first stator element, a second stator element, and a rotor connected to a rotor shaft. The rotor shaft is rotatably mounted in bearings so that the rotor can rotate about a rotation axis. The rotor is arranged between the first and second stator elements, viewed radially to the rotation axis. The first stator element carries a stator winding system, and the second stator element carries a number of permanent magnets that generate magnetic fields that are directed alternately toward and away from the rotor around the rotation axis.The rotor has a number of soft magnetic segments that are evenly distributed tangentially around the rotation axis, with non-magnetic and electrically poorly or non-conductive regions between them. A stator winding system has a number of pole pairs, with respective permanent magnets forming a number of magnetic pole pairs. The number of soft magnetic segments of the rotor is preferably equal to the sum or the difference of the number of pole pairs and the number of magnetic pole pairs.

[0003] The object of the present invention is to provide an electric machine that is compact and can be operated with reduced losses. Furthermore, the object of the present invention is to provide a motor vehicle with such an electric machine.

[0004] This object is achieved by an electric machine having the features of patent claim 1 and by a motor vehicle having the features of patent claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the subclaims.

[0005] A first aspect of the invention relates to an electric machine for driving a motor vehicle, comprising a stator which has a stator carrier element and stator teeth connected to the stator carrier element.

[0006] According to the invention, the electric machine is formed from a first soft magnetic material. This is advantageous because the use of the first soft magnetic material results in low losses, which are at least largely negligible in a relevant frequency range during operation of the electric machine, i.e., very low losses, particularly iron losses due to wire winding-related harmonics and due to a high number of poles. The stator support element can be designed as a stator yoke and referred to as such.

[0007] Such an axial flux machine is often designed with a multiple air gap, preferably with a double air gap, and can be designed, for example, as an external rotor axial flux machine or alternatively as an internal rotor axial flux machine.

[0008] The invention is based on the finding that, particularly in an internal-rotor axial flux machine, which can also be referred to as an I-type axial flux machine, any iron losses during operation of the electrical machine occur primarily in the stator. Compared to an external-rotor axial flux machine, also called an H-type axial flux machine, the internal-rotor axial flux machine has the disadvantage of having a stator yoke, in which additional losses, particularly iron losses, occur compared to the external-rotor axial flux machine. With the present invention, this disadvantage is almost entirely overcome or at least largely minimized.

[0009] In an advantageous development of the invention, the stator support element is designed, at least in some regions, as a winding made from a strip. This is advantageous because it makes production of the stator support element particularly simple. The formation using the winding made from the strip represents a particularly low-cost manufacturing process. In contrast to placing individual sheets next to one another to form a laminated core, the stator support element can be constructed by winding the strip with particularly few individual parts. The winding can preferably be carried out by winding the strip around a longitudinal axis of the stator or the electrical machine. As the strip is wound further, the stator support element can be built up in the radial direction of extension of the stator or the electrical machine.In other words, by successively winding the strip, the stator support element can be built up equally successively in the radial direction of extension of the stator or the electrical machine.

[0010] In a further advantageous development of the invention, at least a partial region of at least one stator tooth of the stator teeth is also provided by the winding formed from the strip. Alternatively, at least a partial region of at least one stator tooth of the stator teeth is integrally connected to the stator support element, which is formed at least partially as a winding formed from the strip.

[0011] Particularly resource-efficient production can be achieved if the winding formed from the strip provides and manufactures not only the stator support element, but also several or all of the stator teeth together with the stator support element. In an alternative embodiment, the stator support element and the stator teeth can also be manufactured separately and then joined together. In this case, a material-to-material connection, particularly in the form of an adhesive bond, between the stator support element and the stator teeth has proven to be both sufficiently durable and easy to manufacture. This alternative embodiment also offers increased flexibility in the choice of material for the stator support element and the stator teeth.It is conceivable not only that the respective stator teeth as a whole are connected to the stator support element in a material-locking manner, in particular by adhesive bonding, but also that only respective partial areas or segments of the stator teeth are connected to the stator support element by the material-locking connection.

[0012] In a further advantageous development of the invention, at least one of the stator teeth is formed, at least in part, from a second soft magnetic material. This is advantageous because the use of the second soft magnetic material results in low losses, in particular iron losses due to wire winding-related harmonics and due to a high number of poles, which are at least largely negligible in a relevant frequency range during operation of the electrical machine. Furthermore, the use of two different soft magnetic materials for the stator support element and the stator teeth allows for a high degree of flexibility in the choice of stator material. Preferably, at least a large part of the at least one stator tooth can be formed, at least in part, from the second soft magnetic material.Preferably, at least half of the stator teeth, particularly preferably all stator teeth, can be formed from the second soft magnetic material.

[0013] In addition, it has been shown that the at least one stator tooth, preferably a plurality of stator teeth and particularly preferably all stator teeth comprise or comprise at least partially a grain-oriented electrical sheet.

[0014] In a further advantageous development of the invention, the second soft magnetic material is a metallic glass or comprises FeSi. The advantage here is that metallic glass, on the one hand, has a high electrical resistance, which leads to low eddy current losses, and, on the other hand, has low coercive field strengths, which leads to low magnetic reversal losses. Alternatively, the second soft magnetic material can comprise FeSi, which has a higher saturation polarization than metallic glass. Metallic glass can also be referred to as amorphous glass or an amorphous alloy. For example, the second soft magnetic material can comprise FeSiB (Fe-Si-B), NbCu (Nb-Cu), or FeSiBPCu (Fe-Si-BP-Cu).

[0015] In a further advantageous embodiment of the invention, the first soft magnetic material is a metallic glass. This is advantageous because metallic glass has a high electrical resistance, which leads to low eddy current losses, and a low coercive field strength, which leads to low magnetic reversal losses. For example, the first soft magnetic material can comprise FeSiB (Fe-Si-B), NbCu (Nb-Cu), or FeSiBPCu (Fe-Si-BP-Cu).

[0016] In a further advantageous development of the invention, the stator support element and at least one of the stator teeth are each formed, at least in part, from FeSi. An advantage here is that FeSi sheets, which can also be called electrical sheets, have a particularly high saturation polarization, which is higher than the saturation polarization of metallic glasses. This allows metallic glasses to be used selectively in particularly loss-critical areas of the electrical machine.

[0017] In a further advantageous development of the invention, the electric machine is designed as an axial flux machine. Configuring the electric machine as an axial flux machine enables a particularly compact and thus space-saving arrangement of the axial flux machine on the motor vehicle, for example, between the respective drive wheels of the motor vehicle.

[0018] In a further advantageous development of the invention, the electric machine is designed as an internal rotor axial flux machine. Configuring the electric machine as an internal rotor axial flux machine offers particularly good utilization of the active volume of the electric machine for torque generation. Furthermore, the internal rotor axial flux machine design achieves a particularly advantageous ratio of compensating surfaces to the available volume occupied by this axial flux machine, allowing the use of short winding heads encompassing the respective wire windings by tooth-wound coil windings.

[0019] A second aspect of the invention relates to a motor vehicle having an electric machine designed as the drive motor of the motor vehicle according to the first aspect of the invention. A motor vehicle powered by this drive motor can be operated with particularly low losses in a small available installation space.

[0020] The preferred embodiments and their advantages presented with respect to one of the aspects apply accordingly to the other aspects of the invention and vice versa.

[0021] The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0022] Further advantages, features and details of the invention emerge from the claims, the following description of preferred embodiments and from the drawings.

[0023] The invention is explained once again below using a specific embodiment. This shows: Fig. 1 is a schematic representation of a motor vehicle, with an electric machine designed as the drive machine of the motor vehicle, which is shown in a schematic side view and is designed as an internal rotor axial flux machine; Fig. 2 a plan view of a schematically illustrated stator support element and stator teeth integrally connected thereto of a stator of the electrical machine shown only in parts; and Fig. 3 a schematic perspective view of a segment of the stator, on whose stator support element several stator teeth are arranged and materially connected to the stator support element.

[0024] Fig. 1 shows a schematic representation of a motor vehicle K with an electric machine 100 designed as the drive motor of the motor vehicle K. The electric machine 100 is designed as an internal rotor axial flux machine and has two stators 10, between which a rotor 12 of the electric machine 100 is rotatably arranged. The rotor 12 is thus designed as a so-called internal rotor of the electric machine 100 (internal rotor axial flux machine). In addition, Fig. 1 shows an axial extension direction A of the stators 10, which is indicated by an arrow and is oriented coaxially to a rotational axis of the electric machine 100. A longitudinal axis of the stators 10 and the rotor 12 is also oriented coaxially to the axial extension direction A and to the rotational axis. Another arrow represents Fig. 1 shows a radial extension direction R of the stators 10, the rotor 12 and the electrical machine 100.

[0025] Fig. 2 shows a plan view of one of the stators 10 along the axial extension direction A, wherein only parts of the stator 10 are shown. Statements relating to one of the stators 10 generally apply to all stators 10 of the electrical machine 100. In the present case, Fig. 2 shows a stator support element 20, which is designed as a stator yoke. Stator teeth 50, 60 are arranged on the stator support element 20 in a circumferential direction U of the stator 10 and the stator support element 20, indicated by a curved arrow, and are integrally connected to the stator support element 20. Fig. 2 shows only two stator teeth 50, 60 of a plurality of stator teeth 50, 60, 70, which in the finished stator 10 are evenly distributed in the circumferential direction U along an end face 22 of the stator carrier element 20.

[0026] In general, the stator carrier element 20 can have an annular disk-shaped contour when viewed from the axial extension direction A, as can be seen from Fig. 2. The annular disk-shaped contour is to be understood as meaning that the stator carrier element 20 can have a disk shape, in particular with a circular cross-section, and centrally, i.e. along a central axis of the stator 10, a Fig. 2, but not numbered, can be provided, resulting in the overall annular disk-shaped contour. The stator support element 20 having this annular disk-shaped contour can - for example, in contrast to a hollow cylindrical stator shape typical for radial flux machines - have a significantly greater extension in the radial extension direction R of the stator 10 than in the axial extension direction A. The central axis of the stator 10 can run parallel, in particular coaxially, to the axial extension direction A of the stator 10.

[0027] Fig. Figure 3 shows a schematic perspective view of a segment of the stator 10. The three stator teeth 50, 60, 70, which are integrally connected to the stator support element 20, are shown as examples. Statements regarding one of the stator teeth 50, 60, 70 generally apply to all stator teeth of the stator 10.

[0028] In the electrical machine 100 designed as an axial flux machine, in particular an internal rotor axial flux machine, the stator support element 20 (stator yoke) can be formed from a first soft magnetic material, which can preferably be a metallic glass (amorphous glass). Additionally or alternatively, the stator support element 20 and at least one of the stator teeth 50, 60, 70 can each be formed at least partially from FeSi, in particular FeSi laminated core, or FeCo. Stator teeth 50, 60, 70 comprising FeCo can be designed more compactly, i.e., stator teeth 50, 60, 70 comprising FeSi. From the overview of Fig. 2 and Fig. 3 it can be seen that the stator support element 20 is formed by a winding 30 formed from a strip 32. For reasons of clarity, Fig. 2 shows only a few individual windings of the winding 30. The winding 30 is produced by winding the strip 32 around the longitudinal axis of the stator 10. As the strip 32 is wound further, the stator support element 20 can be constructed in the radial direction R of the stator 10.

[0029] At least one in Fig. 3, the partial region 52 of the stator tooth 50, which is illustrated by way of example with respect to the stator tooth 50, can also be produced during the manufacture of the winding 30 together with the stator support element 20. Purely by way of example, the partial region 52 of the stator tooth 50 can be designed as a stator tooth root region, which can be integrally connected to the stator support element 20 and can be produced during its winding. A stator tooth main region 54, which together with the stator tooth root region (partial region 52) can form the entire stator tooth 50, can be connected to the partial region 52 in a materially bonded manner, for example by an adhesive bond. Based on the further stator teeth 60, 70 in Fig.3 shows that these stator teeth 60, 70 can also be connected as a whole, for example by gluing, to the stator support element 20. The stator teeth 50, 60, 70 have respective tooth tips 56, 66, 76, which prevent any slippage of the wire windings of the finished stator 10 (not shown here) that are held on the stator teeth 50, 60, 70 from the stator teeth 50, 60, 70. In addition, the tooth tips 56, 66, 76 reduce losses during operation of the electrical machine 100. The tooth tips 56, 66, 76 can be provided as a single piece together with the remaining regions of the stator teeth 50, 60, 70 or, alternatively, can be connected, for example, in a materially bonded or form-fitting manner to partial regions of the stator teeth 50, 60, 70 adjacent to the tooth tips 56, 66, 76. It is advantageous if the tooth tips 56, 66, 76 comprise so-called SMC (soft magnetic composite), i.e., made of a soft magnetic composite material, or are formed from SMC.This allows for particularly high flexibility in the design of the tooth tips 56, 66, 76.

[0030] At least one of the stator teeth 50, 60, 70 can be formed, at least in part, from a second soft magnetic material, which can be a metallic glass. The second soft magnetic material can additionally or alternatively comprise FeSi.

[0031] In summary, the stator support element 20 (here: stator yoke) can generally be formed from the first soft magnetic material, which is particularly low-loss or at least largely loss-free in a relevant frequency range. The stator teeth 50, 60, 70 can preferably be formed, at least in part, but particularly advantageously completely, from the second soft magnetic material. The first soft magnetic material can be provided as the strip 32 and formed into the stator support element 20 by the winding 30. The strip 32 can be wound onto suitable peripheral components, for example housing regions or housing parts of a housing (not shown in detail) of the electrical machine 100, and thereby fastened, so that the stator support element 20 can be formed and thus provided as a laminated core wound in the radial direction R.

[0032] If the stator teeth 50, 60, 70 are made of the same material (first soft magnetic material) as the stator support element 20, the stator teeth 50, 60, 70 can be manufactured, for example, entirely, i.e., together with the respective tooth tips 56, 66, 76 of the respective stator teeth 50, 60, 70, from the strip 32 during winding of the winding 30. If the stator teeth 50, 60, 70 are at least partially made of a different material (second soft magnetic material), the corresponding stator teeth 50, 60, 70 can be attached to the stator yoke using a suitable technology, such as adhesive bonding, and suitable peripheral components.

[0033] In a particularly advantageous variant, the stator support element 20 can be wound from the strip 32, wherein the strip 32 can be formed from metallic glass, also called amorphous glass. The stator teeth 50, 60, 70 and their tooth tips 56, 66, 76 (stator tooth tips) can be made of a FeSi sheet. List of reference symbols 10 Stator 12 Rotor 20 Stator carrier element 22 front side 30 windings 32 volumes 50 stator teeth 52 sub-area 54 Stator tooth main area 56 tooth head 60 stator teeth 66 tooth head 70 stator teeth 76 tooth head 100 electric machine A Axial extension direction K Motor vehicle R radial extension direction U circumferential direction QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2 770 616 A1

[0002]

Claims

[1] Electric machine (100) for driving a motor vehicle (K), with a stator (10) which has a stator carrier element (20) and stator teeth (50, 60, 70) connected to the stator carrier element (20), characterized by that the stator support element (20) is formed at least in regions from a first soft magnetic material. [2] Electrical machine (100) according to claim 1, characterized by that the stator support element (20) is designed at least in regions as a winding (30) formed from a strip (32). [3] Electrical machine (100) according to claim 2, characterized bythat at least a partial area (52) of at least one stator tooth (50) of the stator teeth (50, 60, 70) is also provided by the winding (30) formed from the strip (32) and / or that at least a partial area (32) of at least one stator tooth (50) of the stator teeth (50, 60, 70) is integrally connected to the stator carrier element (20) which is formed at least in regions as a winding (30) formed from the strip (32). [4] Electrical machine (100) according to one of the preceding claims, characterized by that at least one of the stator teeth (50, 60, 70) is formed at least in regions from a second soft magnetic material. [5] Electrical machine (100) according to claim 4, characterized by that the second soft magnetic material is a metallic glass or comprises FeSi. [6] Electrical machine (100) according to one of the preceding claims, characterized by that the first soft magnetic material is a metallic glass. [7] Electrical machine (100) according to one of the preceding claims, characterized by that the stator carrier element (20) and at least one of the stator teeth (50, 60, 70) are each formed at least partially from FeSi. [8] Electrical machine (100) according to one of the preceding claims, characterized by that the electrical machine (100) is designed as an axial flux machine. [9] Electrical machine (100) according to claim 8, characterized by that the electrical machine (100) is designed as an internal rotor axial flux machine. [10] Motor vehicle (K) with an electric machine (100) designed as a drive machine of the motor vehicle according to one of the preceding claims.

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