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 (ST) has at least two stator support element parts (20, 40) comprising different materials, of which a first stator support element part (20) is connected to the stator teeth (50, 60, 70) and is arranged between the stator teeth (50, 60, 70) and a second stator support element part (40) of the at least two stator support element parts (20, 40) which comprises at least a portion of a soft magnetic material.

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 stator support element comprises at least two stator support element parts comprising different materials, of which a first stator support element part is connected to the stator teeth and is arranged between the stator teeth and a second stator support element part of the at least two stator support element parts, which at least partially comprises a soft magnetic material. The first stator support element can preferably be connected directly to the stator teeth. By constructing the stator support element from the first stator support element part and the second stator support element part, a combination of different materials can be used for the respective different stator support element parts, which contributes to minimizing magnetic losses, while simultaneously keeping the manufacture of the stator support element simple.While the second stator support element part comprises the soft magnetic material, i.e., for example, it can be formed entirely or at least predominantly from the soft magnetic material, the first stator support element part can, for example, be formed from an FeSi laminated core, preferably from a grain-oriented sheet, and thus from a material that is particularly favorable for alternating magnetization.

[0007] The first stator support element part and the second stator support element part can, for example, have a geometric similarity to one another with regard to their respective outer contours, viewed in the axial direction of the stator, whereby the first stator support element part and the second stator support element part can be placed against one another over a large area and joined together particularly easily, for example by a material connection, in particular by adhesive bonding. Thus, the two stator support element parts can each have an annular disk-shaped contour, viewed in the axial direction of extension, for example. However, the two stator support element parts can each have a different stator support element part thickness.

[0008] The use of the first soft magnetic material advantageously 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. These losses, in particular iron losses due to harmonics caused by wire windings and due to a high number of poles, occur. The stator support element formed from the two stator support element parts can be designed as a stator yoke and referred to as such. The first stator support element part can also be referred to as the tooth mounting yoke, whereas the second stator support element part can also be referred to as the main yoke.

[0009] 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.

[0010] 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.

[0011] In an advantageous development of the invention, the first stator support element part is designed, at least in regions, as a winding made from a strip. This is advantageous because it makes production of the first stator support element part 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 first stator support element part 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 winding of the strip progresses, the first stator support element part 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 constructed equally successively in the radial direction of extension of the stator or the electrical machine.

[0012] 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. Additionally or alternatively, at least a partial region of at least one stator tooth of the stator teeth is integrally connected to the first stator support element part, which is formed at least partially as a winding formed from the strip.

[0013] Particularly resource-efficient production can be achieved if the winding formed from the strip provides and manufactures not only the first stator support element part, but also several or all of the stator teeth together with the first stator support element part. In an alternative embodiment, the first stator support element part and the stator teeth can also be manufactured separately and then joined together. In this case, a material-to-material connection, in particular in the form of an adhesive connection, between the first stator support element part 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 first stator support element part and the stator teeth.It is conceivable not only that the respective stator teeth as a whole are connected to the first stator support element part in a materially bonded manner, in particular by gluing, but also that only respective partial areas or segments of the stator teeth are connected to the first stator support element part by the materially bonded connection.

[0014] In a further advantageous development of the invention, the second stator support element part is designed, at least in some regions, as a second winding formed from a second strip. This is advantageous because it allows for particularly low-cost production of the second stator support element part. The second strip can be referred to as a stator yoke strip, and the second winding as a stator yoke winding.

[0015] In addition, it has been shown to be advantageous if 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.

[0016] In a further advantageous development of the invention, the first stator support element part and / or at least one of the stator teeth comprises FeSi, in particular a FeSi laminated core comprising a grain-oriented sheet. An advantage here is that FeSi sheets, which can also be called electrical sheets, have a particularly high saturation polarization, which is, for example, higher than the saturation polarization of metallic glasses. For example, metallic glasses, which are also called amorphous glasses, can be selectively used in particularly loss-critical areas of the electrical machine, whereas FeSi sheets can be used in other areas.

[0017] In a further advantageous embodiment of the invention, the soft magnetic material is a metallic glass. This is advantageous because 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 remagnetization losses.

[0018] In a further advantageous development of the invention, the first stator support element part has a first stator support element part thickness oriented in the axial extension direction of the stator, which corresponds to less than one-third or equal to one-third of a second stator support element part thickness assigned to the second stator support element part. This size ratio, in which the first stator support element part thickness of the first stator support element part is less than or equal to one-third of the second stator support element part thickness of the second stator support element part, has proven particularly advantageous with regard to a particularly good compromise between mechanical and electromagnetic properties of the entire stator support element.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Further advantages, features and details of the invention emerge from the claims, the following description of preferred embodiments and from the drawings.

[0025] 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, the stator support element of which has a first stator support element part and a second stator support element part connected to it by adhesive bonding, wherein a plurality of stator teeth are arranged on the first stator support element part and are integrally connected to the first stator support element part.

[0026] 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 axial flux machine, in the present example 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.

[0027] 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 ST, which is designed as a stator yoke. The stator support element ST has two stator support element parts 20, 40, namely a first stator support element part 20 and a second stator support element part 40. In the plan view of the stator 10 along the axial extension direction A, Fig. 2, only the first stator support element part 20 can be seen, since this completely covers the second stator support element part 40. Both the first stator support element part 20 and the second stator support element part 40 have a respective annular disk-shaped contour, as clearly shown in Fig. 2 based on the first stator support element part 20. The term "annular disk-shaped contour" is to be understood as meaning that the first stator support element part 20 or second stator support element part 40 can have a respective disk shape, in particular with a circular cross-section, and a through-opening can be provided centrally, i.e. along a central axis of the stator 10, so that the annular disk-shaped contour is obtained overall. The first or second stator support element part 20 or 40 having this annular disk-shaped contour can - for example, in contrast to a hollow cylindrical stator shape typical for radial flow machines - have a significantly greater extent in the radial direction of extension R of the stator 10 than in the axial direction of extension A. The central axis of the stator 10 can run parallel, in particular coaxially, to the axial direction of extension A of the stator 10.A rotor shaft of the rotor 12, not further specified, can be guided through the through opening of the stator 10, as shown in . Fig. 1 can be seen.

[0028] On the first stator support element part 20, more precisely on an end face 22 of the first stator support element part 20, respective stator teeth 50, 60 are arranged in a circumferential direction U of the stator 10 and of the stator support element SP, indicated by a curved arrow, and are thereby integrally connected to the first stator support element part 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 the end face 22 of the first stator support element part 20. Respective wire windings of the stator 10 received on the teeth 50, 60, 70 are not shown for reasons of clarity.

[0029] Fig. 3 shows a schematic perspective view of a segment of the stator 10 and thereby of the stator support element 20. In Fig. 3 shows, by way of example, the three stator teeth 50, 60, 70, which are integrally connected to the first stator support element part 20. Statements relating to one of the stator teeth 50, 60, 70 generally apply to all stator teeth of the respective stator 10. The first stator support element part 20 can have a first stator support element part thickness D1 oriented in the axial extension direction A of the stator 10, which corresponds to less than one third or equal to one third of a second stator support element part thickness D2 assigned to the second stator support element part 40, although this is Fig. 3 is shown differently. In Fig. 3 shows a variant in which the first stator support element part thickness D1 corresponds exemplarily to the second stator support element part thickness D2, in other words the stator support element part thicknesses D1, D2 are of equal size and accordingly the respective stator support element parts 20, 40 are of equal thickness in the axial extension direction A.

[0030] In the electric machine 100, the stator support element 20 (stator yoke) can be formed at least in regions from a soft magnetic material, which can preferably be a metallic glass (amorphous glass).

[0031] The first stator support element part 20 and the second stator support element part 40 each comprise different materials. The first stator support element part 20 is directly connected to the stator teeth 50, 60, 70. Preferably, the first stator support element part 20 and the stator teeth 50, 60, 70 can be manufactured together.

[0032] The first stator support element part 20 is arranged between the stator teeth 50, 60, 70 and the second stator support element part 40, which at least partially comprises the soft magnetic material.

[0033] From the overview of Fig. 2 and Fig. 3 shows that the first stator support element part 20 is formed by a winding 30 formed from a strip 32. The winding 30 is also referred to below as the first winding 30.

[0034] In Fig. 3 shows that the second stator support element part 40 can be formed at least partially, preferably completely, as a second winding 44 formed from a second band 42.

[0035] For reasons of clarity, Fig. 2 only a few individual windings of the winding 30 are shown. The Fig. 3 is produced by winding the strip 32 around the longitudinal axis of the stator 10. As the strip 32 is wound further, the first stator support element part 20 can be constructed in the radial direction R of the stator 10. Fig. The second winding 44, partially shown in Figure 3, is produced by winding the strip 42 around the longitudinal axis of the stator 10. As the strip 42 is wound, the second stator support element part 40 can be constructed in the radial extension direction R of the stator 10.

[0036] 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 manufactured during the manufacture of the winding 30 together with the first stator support element part 20. Purely by way of example, the partial region 52 of the stator tooth 50 can be configured as a stator tooth root region, which can be integrally connected to the first stator support element part 20 and manufactured during the manufacture of the winding 30. 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.

[0037] In the present case, it is provided that all teeth 50, 60, 70 are constructed during the manufacture of the first stator support element part 20. During the manufacture of the first winding 30, the first stator support element part 20 and the teeth 50, 60, 70 can therefore be formed together. In other words, the teeth 50, 60, 70 can be formed with the first stator support element part 20 during the manufacture of the first winding 30.

[0038] Based on the additional stator teeth 60, 70 in Fig.3 that these stator teeth 60, 70 can also be connected as a whole, for example by gluing, to the first stator support element part 20. The stator teeth 50, 60, 70 have respective tooth tips 56, 66, 76, which prevent any slipping of wire windings of the finished stator 10 (not shown here) received on the stator teeth 50, 60, 70 from the stator teeth 50, 60, 70. The tooth tips 56, 66, 76 can be provided in one 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. Fastening by means of a screw connection is also conceivable.

[0039] In summary, the second stator support element part 40 (also called the main yoke) can generally be formed from the particularly low-loss or, in a relevant frequency range, at least largely loss-free, soft magnetic material. The stator teeth 50, 60, 70 can preferably be formed, at least in part, but particularly advantageously entirely, from an FeSi laminated core and, in particular, can be manufactured together with the first stator support element part 20. Thus, both the first stator support element part 20 and the stator teeth 50, 60, 70 can advantageously be formed from the FeSi sheet, particularly preferably from grain-oriented sheet. The soft magnetic material can be provided as the second strip 42 and formed into the second stator support element part 40 by the second winding 44.The second band 42 can be wound onto suitable peripheral components, for example housing regions or housing parts of a housing (not shown in more detail) of the electrical machine 100, and thereby fastened, so that the second stator support element part 40 can be produced as a laminated core wound in the radial extension direction R and can thus be provided.

[0040] If the stator teeth 50, 60, 70 are made of the same material as the first stator support element part 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, the corresponding stator teeth 50, 60, 70 can also be attached to the first stator support element part 20 using a suitable technology, such as adhesive bonding, a form fit, and / or a screw connection.

[0041] It is also advantageous to construct the first stator support element part 20 and at least one of the stator teeth 50, 60, 70 at least partially from FeCo. Stator teeth 50, 60, 70 comprising FeCo can be more compact than stator teeth 50, 60, 70 comprising FeSi. List of reference symbols 10 Stator 12 Rotor 20 first stator carrier element part 22 front side 30 windings 32 volumes 40 second stator carrier element part 42 second volume 44 second winding 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 D1 First stator support element part thickness D2 Second stator support element part thickness K Motor vehicle ST stator carrier element 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 (ST) and stator teeth (50, 60, 70) connected to the stator carrier element (ST), characterized by in that the stator support element (ST) has at least two stator support element parts (20, 40) comprising different materials from one another, of which a first stator support element part (20) is connected to the stator teeth (50, 60, 70) and is arranged between the stator teeth (50, 60, 70) and a second stator support element part (40) of the at least two stator support element parts (20, 40) comprising a soft magnetic material at least in some regions. [2] Electrical machine (100) according to claim 1, characterized by that the first stator support element part (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 first stator carrier element part (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 the second stator support element part (40) is designed at least in regions as a second winding (44) formed from a second band (42). [5] Electrical machine (100) according to one of the preceding claims, characterized by that the first stator support element part (20) and / or at least one of the stator teeth (50, 60, 70) comprises FeSi, in particular an FeSi laminated core comprising a grain-oriented sheet. [6] Electrical machine (100) according to one of the preceding claims, characterized by that the soft magnetic material is a metallic glass. [7] Electrical machine (100) according to one of the preceding claims, characterized by in that the first stator support element part (20) has a first stator support element part thickness (D1) oriented in the axial extension direction (A) of the stator (10), which corresponds to less than one third or equal to one third of a second stator support element part thickness (D2) assigned to the second stator support element part (40). [8] Electrical machine (100) according to one of the preceding claims, characterized by that the electrical machine (100) is 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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