Stator for electric machine, electric machine and motor vehicle

Abstract

The invention relates to a stator for an electric machine, an electric machine with the stator and a motor vehicle with the electric machine. The stator (10) has: a stator body (12) having a plurality of stator slots (14), in each stator slot (14) a plurality of conductors (22) being arranged one above the other in a radial direction (R); and a plurality of spacer elements (26, 34) which are designed to maintain a predetermined distance between the conductors and to maintain a distance of the respective conductor from the slot wall (18) of the stator body, whereby a respective cooling channel (28) through which a cooling fluid can flow is reserved within the stator slot, which cooling channel is delimited at least in some regions by the respective conductor, according to the invention, a cooling fluid can flow directly along the conductors, each conductor has an angled shape in its cross section, and each of the angled corners (24) of all conductors is supported on the other conductor and / or on the groove wall by means of a respective spacer element.

Description

Technical Field

[0001] The invention relates to a stator for an electric machine, an electric machine having a stator, and a motor vehicle having an electric machine. Background Art

[0002] DE102021133992A1 discloses a stator for an electric motor, which comprises a stator body having a plurality of stator teeth distributed in the circumferential direction and stator slots formed between the stator teeth and extending through the stator in the axial direction. Electrical conductors of a stator winding are accommodated in the stator slots and are arranged substantially radially one above the other. The stator slots have a slot bottom at their radially outer ends along their radial extension and a slot opening at their radially inner ends. Here, the slot openings are respectively closed by slot closing devices. Each stator slot is separated from the stator winding by an insulating device, wherein the insulating device and the slot closing device are formed in one piece, in particular in one piece, with each other. At least one of the insulating devices may have a spacing element extending into the corresponding stator slot, which spacing element separates the electrical conductor from the insulating device while forming a channel through which flow can flow.

[0003] In addition, WO2022 / 188916A1 discloses a stator for an electric motor, which includes a stator body having a plurality of stator teeth distributedly arranged in the circumferential direction and stator slots formed between the stator teeth and extending through the stator in the axial direction. Stator windings arranged radially overlapping each other are accommodated in the stator slots, and each stator winding is respectively covered by an insulating portion. The insulating portion at least partially abuts against the stator slot. The insulating portion has a surface with a rectangular cross-section. The design of the insulating portion has abutment sections at the four corners of the rectangular basic cross-section of the wave winding, and these abutment sections together with the circumferential surface of the stator slot constitute cooling channels for direct slot cooling. Summary of the invention

[0004] The object of the present invention is to provide a solution which allows direct slot cooling of conductors arranged in stator slots and which allows limiting vibrations of the conductors in the stator slots.

[0005] According to the present invention, this task is solved by the technical solution of the independent claim. Other possible design solutions of the present invention are disclosed in the dependent claims, the specification and the drawings. The features, advantages and possible design solutions set forth in the scope of the description of one of the technical solutions of the independent claims should at least be similarly regarded as the features, advantages and possible design solutions of the corresponding technical solutions of the other independent claims and any possible combination of the technical solutions of the independent claims (combined with one or more of the dependent claims, if necessary).

[0006] The invention relates to a stator for an electric machine, in particular a traction machine of a motor vehicle. The traction machine is in particular designed to drive the motor vehicle by means of electrical energy from a vehicle battery. In addition, the electric machine has a rotor which rotates relative to the stator about an axis of rotation during operation. In particular, the stator is designed to be installed in a radial flux machine. The stator comprises a stator body which can in particular comprise a plurality of stator laminations stacked one on top of the other in a stacking direction and can thus be constructed as a lamination stack. In this case, the stacking direction of the stator laminations extends in particular parallel to the axis of rotation of the rotor of the electric machine for which the stator is provided.

[0007] The stator body has a plurality of stator slots distributedly arranged around the central axis of the stator in the circumferential direction. These stator slots extend in particular over the entire axial length of the stator, wherein the axial length extends parallel to the stacking direction or parallel to the rotation axis of the rotor or parallel to the central axis of the stator. With respect to the radial direction of the stator perpendicular to the axial direction, the stator slots extend in particular in a star shape from the central axis of the stator into the stator body. In each stator slot, a plurality of conductors are arranged one on top of the other in a radial direction extending perpendicular to the central axis. These conductors may in particular be so-called hairpins. The conductor may in particular be implemented as a copper wire.

[0008] In addition, the stator includes a plurality of spacing elements, which are designed to maintain a predetermined spacing between the conductors in the radial direction and to maintain the spacing between the corresponding conductor and the slot wall of the stator slot to which the stator body is assigned. The corresponding spacing elements are constructed separately from the conductors. Therefore, the spacing elements are not part of the insulation of the corresponding conductors. In particular, the corresponding spacing elements are respectively attached to at least one of the conductors in order to position the conductor or maintain the spacing between the conductor and another conductor and / or the slot wall. By maintaining the corresponding spacing, corresponding cooling channels that can be flowed by cooling fluid are reserved inside the stator slot, and these cooling channels are at least partially defined by the corresponding conductors. Since the cooling channels are at least partially defined by the corresponding conductors, the cooling fluid flows directly along the conductor when the stator is used in accordance with the regulations. The cooling fluid is designed to receive heat from the corresponding conductor to cool the corresponding conductor. Therefore, when the cooling fluid flows through the corresponding cooling channel, direct cooling of the corresponding conductor can be achieved by means of the cooling fluid. The corresponding conductor can thus be cooled particularly effectively.

[0009] In the stator, it is further provided that each of the conductors has an angular shape, in particular a rectangular shape, in its cross section extending perpendicularly to the central axis. It is further provided that each of the rectangular corners of all conductors is supported on another conductor and / or on the slot wall by means of a corresponding spacing element. This means that each corner of each conductor in the stator slot is supported by means of an associated spacing element. This makes it possible to particularly well limit the vibration of the corresponding conductor inside the stator slot. In addition, the corresponding conductor can be particularly well positioned in the corresponding stator slot via the associated spacing element.

[0010] In a possible further development of the invention, it is provided that the conductors are clamped in the respective stator slots by means of spacer elements. This means that the spacer elements are designed to press the conductors into the associated stator slots. For this purpose, the respective spacer elements can have an interference fit and be at least partially compressed in order to clamp the respective conductors in the stator slots. This ensures that the respective conductors are reliably held in a position fixedly predefined for the respective conductors within the stator slots.

[0011] In another possible design of the present invention, it is provided that at least one of the spacing elements closes the slot opening of the associated stator slot radially inwardly toward the central axis. This means that at least one of the spacing elements has the shape of a slot closing wedge at least partially, whereby the slot opening of the stator slot can be reliably closed inwardly toward the central axis by means of the region of the spacing element configured as a slot closing wedge. This can limit, in particular, prevent the cooling fluid guided in the stator slot, in particular the cooling fluid guided in the cooling channel from flowing out of the stator slot via the slot opening. Therefore, the guidance of the cooling fluid can be particularly well limited to the cooling channel in the stator slot. Therefore, the risk of leakage of the cooling fluid via the slot opening can be kept particularly low. This can ensure that each cooling channel can be flowed through by sufficient cooling fluid during operation due to the prevented leakage. This can in turn ensure effective and limited cooling of the corresponding conductor in the stator slot by means of the cooling fluid flowing in the cooling channel.

[0012] In this regard, it can be provided in particular that the spacing element of the closed slot opening has a U-shape. Here, each side of the U-shape abuts against a corresponding corner of the angular cross section of the following conductor in the stator slot and thus against the edge of the conductor, the conductor having the minimum spacing relative to the central axis of the stator in the radial direction. This means that the side of the U-shape of the spacing element abuts against the conductor in the stator slot that is in the innermost direction with respect to the radial direction. The inner side of the spacing element facing the conductor defines a cooling channel together with the conductor, which forms the bottom of the U-shaped recess. The cooling channel partially covers the conductor in the radial direction in the stator slot in the radial direction towards the central axis. Here, the inner side of the spacing element faces the following side of the conductor in the radial direction, which is arranged towards the central axis of the stator. In other words, the spacing element of the closed slot opening defines one of the cooling channels together with the conductor in the radial direction in the stator slot, whereby the conductor in the radial direction in the innermost direction can be cooled particularly effectively on its side facing the central axis by means of a cooling fluid flowing through the cooling channel.

[0013] In another possible design of the present invention, it is provided that at least one of the spacing elements is designed to support two corners of the corresponding cross-sectional shapes of two different conductors to each other and to the slot wall. To this end, the spacing element can be arranged in particular in the radial direction between the corresponding conductors to be supported. Thus, the first edge of the first conductor, which is further arranged radially on the outside and abuts radially from the outside on the spacing element, and the radially inner edge of the second conductor, which abuts radially from the inside on the spacing element, can be supported to each other by means of the spacing element. In addition, the spacing element abuts on the slot wall in the circumferential direction extending around the central axis, whereby the two corners of the corresponding angular cross-sections of these different conductors are supported to the slot wall. This means that, by means of the spacing element, the positions of the corresponding corners of the cross-sections of the different conductors are precisely predetermined both to each other and to the slot wall. The spacer elements arranged in the radial direction between the conductors arranged in a common stator slot support different conductors adjacent to each other in the radial direction at the corners of their cross section facing each other in the radial direction, wherein the corners supported by the spacer elements are arranged in the circumferential direction facing the same slot wall of the stator slot. Since two edges of two different conductors are supported together by means of the at least one spacer element, the stator can be designed with particularly few spacer elements and thus in a particularly simple and low-weight manner, by means of which all corners of the cross section of all conductors within a stator slot are supported by means of particularly few spacer elements.

[0014] In another possible design of the present invention, it is provided that each side surface of each conductor locally defines at least one cooling channel. This makes it possible that during operation, each side surface of each conductor is flowed through by the cooling fluid flowing in the corresponding cooling channel and is thereby cooled. Therefore, particularly uniform and reliable cooling of each conductor arranged in a stator slot can be achieved.

[0015] In another possible embodiment of the present invention, each of the slot walls defining the stator slots is insulated with a slot insulation. The slot insulation can also be referred to as a so-called slot bottom insulation. The slot insulation serves to electrically insulate the lamination stack from the conductor. In addition, the slot insulation serves to mechanically protect the conductor from sharp edges of the stator body. The slot insulation can be configured, for example, as a paper insulation.

[0016] The invention further relates to an electric machine having a stator as has already been described in connection with the stator according to the invention. The electric machine is in particular a traction machine for an electric motor vehicle. The electric machine is designed to drive the motor vehicle.

[0017] The invention further relates to a motor vehicle having an electric machine as has already been described in conjunction with the electric machine according to the invention. The electric machine is designed to drive the motor vehicle by means of electrical energy.

[0018] Other features of the invention can be derived from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned above in the description and the features and feature combinations mentioned below in the description of the drawings and / or shown individually in the drawings can be used not only in the respectively given combination but also in other combinations or individually without leaving the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The attached figure is in the only figure ( Figure 1 ) shows a schematic cross-sectional view of a stator slot of a stator, in which a plurality of conductors are stacked one on top of the other in the radial direction. DETAILED DESCRIPTION

[0020] exist Figure 1 1 shows a stator 10 of an electric motor for a motor vehicle in a partially cutaway manner. The stator 10 comprises a stator body 12, which is in the present case designed as a laminated core. The stator body 12 has an at least substantially hollow cylindrical geometry, wherein the stator body 12 is designed at least substantially symmetrically with respect to the center axis of the stator 10. An axial direction A of the stator 10 extends in the direction of the longitudinal extension of the center axis of the stator 10. A radial direction R of the stator 10 is perpendicular to the axial direction A. Figure 1 In the view shown, the axial direction A extends into the plane of the drawing. A circumferential direction U of the stator 10 extends around the center axis of the stator 10 .

[0021] The stator body 12 has a plurality of stator slots 14 distributedly arranged around the center axis of the stator 10 in the circumferential direction U. The stator slots 14 extend in particular over the entire length of the stator body 12 extending in the axial direction A and extend in the radial direction R from the center of the stator 10 into the stator body 12. The corresponding stator slots 14 adjacent to each other in the circumferential direction U are separated from each other by a stator tooth 16 arranged between these stator slots 14 in the circumferential direction U. Here, the outer side of the stator tooth 16 forms a slot wall 18 that defines the corresponding stator slot 14. As shown in Figure 1 1 and 2 , it can be seen that a slot insulation 20 is arranged in the stator slot 14 shown, which slot insulation rests on the slot wall 18 which delimits the stator slot 14 . The respective slot wall 18 is thus insulated by means of the slot insulation 20 .

[0022] As in Figure 1 It can be further seen in FIG that a plurality of conductors 22 are arranged side by side in the radial direction R in the stator slot 14. Figure 1In the cross section shown extending perpendicularly to the axial direction A, the respective conductor 22 has at least substantially a rectangular cross section. This means that the cross section of the respective conductor 22 has at least substantially four corners 24. For reasons of clarity, only some of the corners 24 of the respective conductor 22 are provided with the corresponding reference numerals. In order to be able to achieve particularly good cooling of the respective conductor 22 in the stator slot 14 on the one hand and to be able to limit the vibration of the conductor 22 in the stator slot 14 particularly well, it is provided that the stator 10 comprises a plurality of spacing elements 26. A spacing element 26 rests on each corner 24 of each conductor 22. In order to be able to construct the stator 10 with particularly few spacing elements 26, it is currently provided that some of the spacing elements 26 rest on the corners 24 of the cross section of the conductor 22 directly adjacent to each other in the radial direction R, which face each other in the radial direction R. This means that two corners 24 of the cross-sectional shapes of two different conductors 22 support each other by means of a single spacing element 26. In the present case, it is also provided that each spacer element 26 is supported on a slot wall 18 delimiting a stator slot 14. For this purpose, each spacer element 26 rests on a slot insulation 20, which in turn rests on the respective slot wall 18. Thus, the edge of the respective conductor 22 corresponding to the corner 24 in cross section is supported on the respective slot wall 18 via the respective spacer element 26 and, if necessary, additionally with respect to the respective other corner 24 of the cross section of the other conductor 22. Thus, the conductor 22 can be positioned particularly precisely in the stator slot 14 via the spacer element 26. Furthermore, by supporting all corners 24 of the cross-sectional shape of each conductor 22, vibrations of the respective conductor 22 within the stator slot 14 can be particularly well limited. Since the spacer elements 26 maintain the respective spacings between the individual conductors 22 and between the conductors 22 and the slot wall 18, in particular the slot insulation 20, respective cooling channels 28 are formed. For reasons of clarity, only some cooling channels 28 are provided with the associated reference numerals.

[0023] The cooling channels 28 are designed to be traversed by a cooling fluid, in particular cooling oil, when the stator 10 is used as specified and when an electric machine having the stator 10 is operated. Direct slot cooling of the stator 10 is thereby achieved. The respective cooling channels 28 are currently defined at least partially by at least one conductor 22. Thus, the cooling fluid flows directly along the conductor 22 defining the cooling channel 28 during operation, whereby the conductor 22 can be particularly well cooled by means of the cooling fluid. It is currently provided that each side 30 of each conductor 22 defines at least one cooling channel 28. This ensures that each side 30 of each conductor 22 is cooled by a flow of cooling fluid during operation. For reasons of clarity, only some of the side 30 of the conductor 22 are provided with the associated reference numerals.

[0024] As in Figure 1As can be seen in FIG. 1 , each stator slot 14 has a slot opening 32 at its inner end facing the center axis of the stator 10 . In order to prevent the cooling fluid from escaping from the stator slot 14 via the slot opening 32 , it is provided that one of the retaining spacer elements 26 , which is denoted below by reference numeral 34 , has a U-shaped shape in cross section. Thus, the U-shaped spacer element 34 serves, on the one hand, as a slot closing wedge for the slot opening 32 and, on the other hand, for maintaining a spacing between the conductor 22 that is located innermost with respect to the center axis of the stator 10 and the corresponding slot wall 18 . For this purpose, the respective side legs 36 of the U-shaped cross section of the spacer element 34 respectively abut against the corner 24 of the innermost conductor 22 with respect to the radial direction R. Here, the side legs 36 of the U-shaped cross section of the spacer element 34 abut against the innermost corner 24 of the cross section of the innermost conductor 22 with respect to the radial direction R. The innermost conductor 22 is at the smallest spacing from the center axis of the stator 10 relative to all conductors 22 in the common stator slot 14 .

[0025] The inner side 38 of the bottom of the recess of the spacer element 34, which forms the U-shaped cross section of the spacer element 34, defines one of the cooling channels 28 together with the first conductor 22. The cooling channel 28 covers the innermost conductor 22 partially in the radial direction R toward the center axis of the stator 10. The spacer element 34 with the U-shaped cross section thus makes it possible, on the one hand, to reliably stabilize the innermost conductor 22 at all its corners 24, so that the slot opening 32 is reliably closed and thus sealed, and, in addition, to make it possible, due to the formation of the cooling channel 28 along the side of the innermost conductor 22 facing the center axis, for a cooling fluid to flow during operation in order to cool the innermost conductor 22 particularly effectively.

[0026] In particular, it is provided that the conductors 22 are clamped in the stator slots 14 by means of corresponding spacer elements 26. The spacer elements 26 are combined spacer and clamping elements. Thus, the spacer elements 26 on the one hand fulfill the function of fixing the position of the conductors 22 by virtue of their substantial elasticity, which allows the conductors 22 to be clamped in the stator slots 14 and allows the corresponding cooling channels 28 to be reserved. Furthermore, the spacer elements 26 allow at least substantially constant spacings to be maintained between the respective conductors 22 that are directly adjacent to one another and that all spacings between adjacent conductors 22 are at least substantially the same.

[0027] The described design of the stator 10 enables particularly good cooling of the stator 10. The stator 10 is particularly suitable for use in the high-performance field. In the stator 10, due to the conduction of the cooling fluid in the immediate vicinity of the conductor, a high heat dissipation from the conductor 22 which is subjected to high thermal loads can be achieved. In the stator 10, the oil flow space close to the conductor, in the present case a cooling channel 28, is realized by using a combined spacing and clamping element and thus a spacing element 26. The spacing element 26 is installed between the conductor 22 adjacent in the radial direction R and the stator slot 14 lined with the slot insulation 20 at the corresponding corner 24 of the cross section of the conductor 22. By designing the spacing element 34 with a U-shaped cross section, which is the innermost spacing with respect to the radial direction R and the smallest spacing from the center axis of the stator 10, heat dissipation in the vicinity of the air gap can be achieved by means of the cooling fluid flowing in the cooling channel 28 defined by the spacing element 34.

[0028] In summary, the present invention shows how an oil-conducting topology close to the conductor of an electric drive machine with direct slot cooling can be realized.

[0029] Reference numerals list

[0030] 10 Stator

[0031] 12 stator body

[0032] 14 stator slots

[0033] 16 stator teeth

[0034] 18. Groove wall

[0035] 20 slot insulation

[0036] 22 Conductor

[0037] 24 Corners

[0038] 26 Spacer element

[0039] 28 Cooling channels

[0040] 30 Side

[0041] 32 slot opening

[0042] 34 Spacer element

[0043] 36 Side

[0044] 38 Inside

[0045] A Axial direction

[0046] R Radial direction

[0047] U Circumferential direction

Claims

1. A stator (10) for an electric machine, the stator comprising: a stator body (12), the stator body having a plurality of stator slots (14) distributedly arranged in a circumferential direction (U) around a center axis of the stator (10), a plurality of conductors (22) being arranged one above the other in each stator slot (14) in a radial direction (R) extending perpendicularly to the center axis; and a plurality of spacing elements (26, 34), the spacing elements being designed to maintain a predetermined spacing in the radial direction (R) between the conductors (22) and to maintain a spacing between the respective conductors (22) and a slot wall (18) of the stator body (12) defining the associated stator slot (14), thereby reserving within the stator slot (14) a corresponding cooling channel (28) through which a cooling fluid can flow, the cooling channel being at least partially defined by the respective conductor (22), thereby enabling the cooling fluid to flow directly along the conductor (22), wherein: Each of the conductors (22) has an angular shape in its cross section extending perpendicularly to the center axis, and each of the corners (24) of the angular shape of all conductors (22) is supported on another conductor (22) and / or on a slot wall (18) by means of a corresponding spacing element (26, 34).

2. The stator (10) according to claim 1, characterized in that: The conductor (22) is clamped in the corresponding stator slot (14) by means of the spacer elements (26, 34).

3. The stator (10) according to claim 1 or 2, characterized in that: At least one of the spacer elements (26, 34) closes a slot opening (32) of an associated stator slot (14) radially inwardly toward the center axis.

4. The stator (10) according to claim 3, characterized in that A spacing element (26, 34) closing the slot opening (32) has a U-shape, each of the sides (36) of the U-shape abutting against a respective corner (24) of the cross section of a conductor (22) in the stator slot (14) which has a minimum distance from the center axis in the radial direction R, and an inner side (38) of the spacing element (26, 34) facing the conductor (22) together with the conductor (22) defining a cooling channel (28) which partially covers the conductor (22) in the radial direction (R) towards the center axis.

5. The stator (10) according to any one of the preceding claims, characterized in that At least one of the spacer elements (26) is designed to support two corners (24) of the cross-sectional shapes of two different conductors (22) against each other and against the slot wall (18).

6. A stator (10) according to any one of the preceding claims, characterised in that Each side (30) of each conductor (22) partially defines at least one cooling channel (28).

7. A stator (10) according to any one of the preceding claims, characterised in that Each of the slot walls (18) defining the stator slots (14) is insulated by a slot insulation (20).

8. An electric machine having a stator (10) according to any one of the preceding claims. 9 . A motor vehicle having an electric machine according to claim 8 , which is designed to drive the motor vehicle by means of electrical energy.

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