Stator for an electrical machine for driving a motor vehicle, electrical machine for a motor vehicle, and motor vehicle

Abstract

The invention relates to a stator (10) for an electrical machine (100) for driving a motor vehicle (K), having a stator yoke (20) and having at least one stator tooth (40) that is connected to the stator yoke (20) at a common connecting region (12). The stator yoke (20) has at least one recess (22) at which the at least one stator tooth (40) is held, and a stator yoke wall region (24) assigned to the stator yoke (20), together with a stator tooth wall region (44) assigned to the at least one stator tooth (40), delimits at least one cooling channel sub-region (62) of a cooling channel (60) that is designed to carry coolant (14) through the stator (10). Further aspects of the invention relate to an electrical machine (100) and to a motor vehicle (K).

Description

[0001] Stator for an electric motor for driving a motor vehicle, electric motor for a motor vehicle and motor vehicle

[0002] The invention relates to a stator for an electric motor for driving a motor vehicle, comprising a stator yoke and at least one stator tooth connected to the stator yoke at a common connection area. Further aspects of the invention relate to an electric motor having such a stator and to a motor vehicle.

[0003] Stators of electrical machines can be equipped with windings, particularly endless wave windings, using so-called "hairpin technology," for example. The respective stator teeth, on which these windings may be mounted, are subject to significant heating during operation of electric machines, which can also be referred to as electrical machines. To counteract this heating, cooling is often carried out on the outer circumference of an electric machine's stator using a cooling medium, such as an oil flow. Additionally or alternatively, a water jacket can also be provided, which enables cooling using cooling water.

[0004] DE 102021 214491 A1 discloses a stator for an electrical machine which is arranged around a rotational axis defining an axial direction. The stator has a stator yoke extending in the axial direction and in a direction radial thereto. Stator teeth pointing toward the rotational axis are arranged annularly on the stator yoke along the axial direction and are evenly spaced from one another in the circumferential direction, such that a stator slot is formed between radially adjacent stator teeth. The stator is divided axially centrally into a first stator section and a second stator section. A radially extending first outer wall is provided at the end of the first stator section, and a radially extending second outer wall is provided at the opposite end, each of which serves as an axial support for the stator yoke.A cooling distribution disc is integrated axially centrally between the first stator section and the second stator section.

[0005] DE 10 2016 215483 A1 discloses a stator for an electric machine having a circumferentially closed yoke. The yoke comprises at least one recess formed on the inner circumferential surface, allowing at least one separate tooth to be inserted into the recess.

[0006] The object of the present invention is to provide a stator, an electric machine and a motor vehicle of the type mentioned above, in which improved cooling is possible.

[0007] This object is achieved by a stator having the features of patent claim 1, by an electric motor having the features of patent claim 8, and by a motor vehicle having the features of patent claim 9. Advantageous embodiments with expedient further developments of the invention are specified in the subclaims.

[0008] A first aspect of the invention relates to a stator for an electric machine for driving a motor vehicle, comprising a stator yoke and at least one stator tooth which is connected to the stator yoke at a common connecting region.

[0009] According to the invention, it is provided that the stator yoke has at least one recess on which the at least one stator tooth is held and a stator yoke wall region assigned to the stator yoke, together with a stator tooth wall region assigned to the at least one stator tooth, delimits at least one cooling channel sub-region of a cooling channel which is designed to guide cooling medium through the stator.This is advantageous because it allows the cooling medium to come into direct contact with the stator yoke and the at least one stator tooth, so that heat generated in the stator tooth during operation of the electric machine can be conducted to the stator tooth wall area by heat conduction within the stator tooth and from there transferred to the cooling medium guided in the cooling channel by convective heat transfer on a stator tooth wall area surface that delimits the stator tooth wall area towards the cooling channel, i.e. a surface of the wall area assigned to the stator tooth.On the other hand, heat generated in the stator yoke during operation of the electric motor can be conducted by thermal conduction within the stator yoke to the stator yoke wall area and from there transferred to the cooling medium conveyed in the cooling channel by convective heat transfer at a surface of the stator yoke wall area that delimits the stator yoke wall area toward the cooling channel, i.e., a surface of the wall area associated with the stator yoke. Overall, the delimitation of at least the cooling channel sub-area enables simultaneous, direct contact of at least one stator tooth and the stator yoke with the cooling medium via the cooling channel, thereby enabling direct and thus improved cooling.

[0010] The invention is based on the finding that, in conventional cooling concepts, heat conduction occurs across multiple component boundaries or air gaps, which leads to an undesirable reduction in cooling efficiency. This can result in an overall reduction in cooling performance and thus a lower continuous output of the corresponding electric motor. The invention addresses this issue and contributes to improving cooling performance, since at least the cooling channel area is directly delimited by the stator yoke wall area on the one hand and the stator tooth wall area on the other.

[0011] In an advantageous development of the invention, the stator tooth wall region and the stator yoke wall region are formed from different materials. This is advantageous because it provides increased flexibility in the design of the stator. For example, at least one stator tooth or the stator yoke can be formed from a soft magnetic material.

[0012] In a further advantageous development of the invention, the at least one stator tooth has a stator tooth root region, which is positively connected to the stator yoke at the connecting region. This form-fitting connection is particularly durable, and the stator tooth root region can be in contact with the stator yoke over a large area, thereby enabling effective sealing of at least the cooling channel region against unwanted outward leakage of the cooling medium between the stator yoke and the stator tooth in the radial direction of the stator.

[0013] In a further advantageous development of the invention, the at least one stator tooth is integrally connected to the stator yoke at the common connection area. This is advantageous because it allows a material connection to be formed, which, on the one hand, contributes to holding the at least one stator tooth to the stator yoke and, on the other hand, can serve to seal the cooling channel. The material connection can preferably be provided by an adhesive connection between the stator yoke and the at least one stator tooth.

[0014] In a further advantageous development of the invention, a turbulence-generating element for generating turbulence of the cooling medium is arranged at least in the cooling channel sub-region. This is advantageous because the generation of turbulence can generate an increased heat transfer coefficient on the one hand on a surface of the wall region associated with the stator tooth and on the other hand on a surface of the wall region associated with the stator yoke, which results in improved cooling performance.

[0015] In a further advantageous development of the invention, the at least one stator tooth has a stator tooth turbulence generator region designed to generate turbulence of the cooling medium at least in the cooling channel sub-region. This is advantageous because the generation of turbulence creates an increased heat transfer coefficient at least in the cooling channel sub-region, thereby achieving an improved cooling effect. The stator tooth turbulence generator region can be designed as a projection of the at least one stator tooth and can thus be manufactured particularly easily.

[0016] In a further advantageous development of the invention, the stator yoke has a stator yoke turbulence generator region designed to generate turbulence of the cooling medium at least in the cooling channel sub-region. This is advantageous because the generation of turbulence creates an increased heat transfer coefficient at least in the cooling channel sub-region, thereby achieving an improved cooling effect. The stator yoke turbulence generator region can be designed as a projection of the stator yoke and is thus particularly easy to manufacture.

[0017] In a further advantageous development of the invention, the stator yoke is designed as a stator yoke laminated core and / or the at least one stator tooth is designed as a stator tooth laminated core. This is advantageous because such a laminated core can be manufactured with particularly low effort.

[0018] A second aspect of the invention relates to an electric motor for a motor vehicle, which is designed to drive the motor vehicle and has at least one stator according to the first aspect of the invention. The electric motor, which can also be referred to as a traction motor, has improved cooling, particularly in the area of ​​the stator.

[0019] A third aspect of the invention relates to a motor vehicle with an electric motor according to the second aspect of the invention and / or with a stator according to the first aspect of the invention. The motor vehicle advantageously features improved cooling. The preferred embodiments presented with respect to one of the aspects and their advantages apply accordingly to the other aspects of the invention, and vice versa.

[0020] 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.

[0021] Further advantages, features and details of the invention emerge from the claims, the following description of preferred embodiments and from the drawings.

[0022] The invention is explained once again below using a specific embodiment. This shows:

[0023] Fig. 1 is a schematic plan view along an axial extension direction of a stator and of a partial region of the stator which is assigned to a schematically illustrated electric machine which serves to drive a motor vehicle which is also schematically illustrated;

[0024] Fig. 2 is a detailed view of a section X outlined in Fig. 1, showing exemplary individual windings of the stator as well as cooling channel sub-regions delimited by respective stator teeth and by a stator yoke of the stator, as well as exemplary differently shaped stator tooth turbulence generator regions and stator yoke turbulence generator regions.

[0025] Fig. 3 -

[0026] Fig.6 shows enlarged detailed views of different variants of the stator tooth and the stator yoke with different variants of cooling channel sections.

[0027] Fig. 1 shows an abstract representation of a motor vehicle K, which has at least one electric motor 100, also shown in an abstract representation. The electric motor 100 is designed to drive the motor vehicle K and can also be referred to as a traction motor or an electric drive motor. The electric motor 100 has a stator 10. A rotor of the electric motor 100, which is rotatably mounted relative to the stator 10 during operation of the electric motor 100, is not shown in detail here for reasons of clarity.

[0028] In a schematic plan view along an axial extension direction A of the electric machine 100 and thus of the stator 10, it is shown that the stator 10 has a stator yoke 20 and a plurality of stator teeth 40, which are arranged uniformly on the stator yoke 20 in the circumferential direction U of the stator 10. The following statements regarding one of the stator teeth 40 can apply to all stator teeth 40 of the stator 10. The stator teeth 40 protrude inward from the stator yoke 20 in the radial extension direction R. Furthermore, each stator tooth 40 is connected to the stator yoke 20 at a respective connecting region 12. The radial extension direction R, as well as the axial extension direction A and the circumferential direction U, are indicated by a respective arrow.

[0029] The stator yoke 20 has a plurality of recesses 22, each of which accommodates and securely holds a stator tooth 40. The following statements regarding one of the recesses 22 can apply to all recesses 22 of the stator yoke 20.

[0030] In this case, the stator teeth 40 are positively connected to the stator yoke 20.

[0031] Additionally or alternatively, the stator teeth 40 can also be integrally connected to the stator yoke 20, for example by means of an adhesive bond. Each of the stator teeth 40 has a stator tooth root region 52, which is positively connected to the stator yoke 20 at the connecting region 12. In the present case, the respective stator teeth 40 can form a so-called dovetail connection with the respective recess 22 of the stator yoke 20 at their respective stator tooth root region 52 and at the respective connecting region 12. The respective stator tooth root regions 52 can be seen in Fig. 2, wherein Fig. 2 shows an enlarged view of a section X of the stator 10 outlined in Fig. 1.

[0032] In general, the stator yoke 20 can be designed as a stator yoke laminated core. Additionally or alternatively, the respective stator teeth 40 can be designed as respective stator tooth laminated cores. The term stator yoke laminated core means that the stator yoke 20 can have a plurality of individual stator yoke laminated cores which, when lined up in the axial direction A, form the stator yoke laminated core. The term stator tooth laminated core also means that the respective stator tooth 40 can have a plurality of individual stator tooth laminated cores which, when lined up in the axial direction A, form the stator tooth laminated core. However, it is also conceivable that the stator yoke 20 is designed as an individual part and is manufactured, for example, by a casting process. It is also conceivable that the respective stator teeth 40 are designed as individual parts, in other words as one piece.

[0033] In the recess 22, in which the at least one stator tooth 40 is held, a stator yoke wall region 24 assigned to the stator yoke 20, together with a stator tooth wall region 44 assigned to the respective stator tooth 40, delimits a cooling channel sub-region 62 of a cooling channel 60. The cooling channel 60 is provided for guiding cooling medium 14 through the stator 10. The cooling channel sub-region 62 can generally correspond to a partial section of the cooling channel 60. For example, a plurality of cooling channel sub-regions 62, which are arranged one behind the other in the axial extension direction A, can jointly form the cooling channel 60, in particular if one of the individual stator tooth laminations and one of the individual stator yoke laminations together form one of the cooling channel sub-regions 62.

[0034] Additionally or alternatively, the cooling channel sub-region 62 can also be designed, for example, as a radial sub-section, which can form and delimit the cooling channel 60 in the radial extension direction R in regions.

[0035] For a more flexible design of the electromagnetic properties of the stator 10, the stator tooth wall region 44 and the stator yoke wall region 24 can be formed from different materials. For example, it is conceivable that the stator tooth wall region 44 and thus the stator tooth 40 can be formed from a first soft magnetic material, whereas the stator yoke wall region 24 and thus the stator yoke 20 can be formed from a second soft magnetic material.

[0036] A turbulence-generating element 70 for generating turbulence of the cooling medium 14 can be arranged in the cooling channel 60 or in the respective cooling channel sub-region 62. The turbulence-generating element 70 can, for example, be designed as an individual part provided separately from the respective stator tooth 40 and additionally or alternatively from the stator yoke 20 and thus, for example, be inserted into the recess 22. The turbulence-generating element 70 is shown by way of example in the recess 22 shown on the right outer edge in Fig. 2. In addition or alternatively to the turbulence-generating element 70, each of the stator teeth 40 can have a stator tooth turbulence-generating region 48 designed to generate turbulence of the cooling medium 14 in the cooling channel sub-region 62.Likewise, the stator yoke 20 can have, in at least one of the recesses 22, preferably in all recesses 22, a stator yoke turbulence generator region 38 designed to generate turbulence of the cooling medium 14 in the cooling channel 60 or in the cooling channel sub-region 62. As an example, a winding 16 is also shown in sections in Fig. 2, which can extend at least partially around one of the stator teeth 40.

[0037] From the combined view of Fig. 3, Fig. 4, Fig. 5 and Fig. 6, it can be seen that the recess 22 can have different recess cross-sections, i.e., respective cross-sections of the recess 22, with respect to a plane perpendicular to the axial extension direction A. The same applies to respective cross-sections of the stator yoke wall region 24 and to respective cross-sections of the stator tooth wall region 44.

[0038] The stator 10 is heated by the operation of the electric motor 100, with this heat being generated largely in the windings 16, which are formed, for example, as copper conductors. While in known systems, at least partial dissipation of this heat generally occurs at a stator outer diameter via oil or, for example, via a water jacket, the formation of the cooling channel sub-region 62 based on the stator yoke wall region 24 and the stator tooth wall region 44 enables an improved cooling effect, since, unlike in known systems, heat transfer does not have to occur through multiple component boundaries and additionally or alternatively through materials in order to dissipate heat generated from the stator teeth 40 and the stator yoke 20. Compared to known systems, this results in improved cooling performance and thus a higher continuous output of the electric motor 100 (traction machine) can be achieved.

[0039] In order to achieve a particularly advantageous cooling effect, at least the cooling channel sub-region 62 or the cooling channel 60 can generally extend in the radial direction R beyond the connecting region 12, as can be seen, for example, in Fig. 4 and Fig. 5. Although not shown in more detail here, a particularly favorable cooling effect can generally be achieved and, for example, regardless of the shape of the cooling channel sub-region 62 and thus of the cooling channel 60, if the cooling channel sub-region 62 extends over more than half of a tooth length measured in the radial direction R, i.e. more than half the length of the stator tooth 40. As a result, the cooling medium 14 penetrates particularly far inside the stator tooth 40 in the radial direction R. To simplify manufacture and assembly of the stator 10, the respective stator tooth turbulence generator region 48 can be formed integrally with the stator tooth 40 orthe stator tooth individual lamination and form a partial section of the stator tooth wall region 44. For the same reason, the respective stator yoke turbulence generator region 38 can be integrally connected to the stator yoke 20 or the stator yoke individual lamination and form a partial section of the stator yoke wall region 24.

[0040] In summary, the invention allows the use of an endless wave winding with the windings 16 joined from the outside in the radial direction R, wherein a connection between the stator teeth 40 and the stator yoke 20 at the connecting region 12, which is required anyway for the endless wave winding, is used to form the cooling channel sub-region 62 using the stator yoke wall region 24 and the stator tooth wall region 44. As a result, the connection between the stator yoke wall region 24 and the stator tooth wall region 44 can be used directly to define the cooling channel sub-region 62 and thus also the cooling channel 60 with little effort. This enables cooling close to the heat source and thus results in improved cooling performance, which leads to a higher continuous power output of the electric motor 100 during its operation. The distribution of the cooling medium 14 to the respective cooling channels 60 or 62 arranged next to one another in the circumferential direction U.Cooling channel subregions 62 can be provided, for example, via a particularly ring-shaped distribution channel 18. The distribution channel 18 can be arranged, for example, in the center of the stator 10 in the axial direction A. The distribution channel 18 can be supplied with the cooling medium 14, for example, via respective bores in a housing (not shown) of the electric motor 100.

[0041] List of reference symbols

[0042] 10 Stator

[0043] 12 Connection area

[0044] 14 Cooling medium

[0045] 16 windings

[0046] 18 distribution channel

[0047] 20 Stator yoke

[0048] 22 Recess

[0049] 24 Stator yoke wall area

[0050] 38 Stator yoke turbulence generator area

[0051] 40 stator teeth

[0052] 44 Stator tooth wall area

[0053] 48 Stator tooth turbulence generator area

[0054] 52 Stator tooth root area

[0055] 60 cooling channel

[0056] 62 Cooling channel section

[0057] 70 Turbulence generation element

[0058] 100 electric motor

[0059] A Axial extension direction

[0060] K Motor vehicle

[0061] R radial extension direction

[0062] U circumferential direction

Claims

Claims 1. Stator (10) for an electric machine (100) for driving a motor vehicle (K), with a stator yoke (20) and with at least one stator tooth (40) which is connected to the stator yoke (20) at a common connecting region (12), characterized in that the stator yoke (20) has at least one recess (22) on which the at least one stator tooth (40) is held and a stator yoke wall region (24) assigned to the stator yoke (20) together with a stator tooth wall region (44) assigned to the at least one stator tooth (40) delimits at least one cooling channel sub-region (62) of a cooling channel (60) which is designed to guide cooling medium (14) through the stator (10).

2. Stator (10) according to claim 1, characterized in that the stator tooth wall region (44) and the stator yoke wall region (24) are formed from different materials.

3. Stator (10) according to claim 1 or 2, characterized in that the at least one stator tooth (40) has a stator tooth root region (52) which is positively connected to the stator yoke (20) at the connecting region (12).

4. Stator (10) according to one of the preceding claims, characterized in that the at least one stator tooth (40) is integrally connected to the stator yoke (20) at the common connecting region (12).

5. Stator (10) according to one of the preceding claims, characterized in that a turbulence generating element (70) for generating turbulence of the cooling medium (14) is arranged at least in the cooling channel partial region (62).

6. Stator (10) according to one of the preceding claims, characterized in that the at least one stator tooth (40) has a stator tooth turbulence generator region (48) designed to generate turbulence of the cooling medium (14) at least in the cooling channel partial region (62).

7. Stator according to one of the preceding claims, characterized in that the stator yoke (20) has a stator yoke turbulence generator region (38) designed to generate turbulence of the cooling medium (14) at least in the cooling channel partial region (62).

8. Stator (10) according to one of the preceding claims, characterized in that the stator yoke (20) is designed as a stator yoke laminated core and / or the at least one stator tooth (40) is designed as a stator tooth laminated core.

9. Electric machine (100) for a motor vehicle (K), which is designed to drive the motor vehicle (K) and has at least one stator (10) according to one of claims 1 to 8.

10. Motor vehicle (K) with an electric machine (100) according to claim 9 and / or with a stator (10) according to one of claims 1 to 8.

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