Slot lock for stator, stator and motor

Abstract

The invention relates to a slot lock for electrically insulating a first stator segment with respect to a second stator segment of the stator, to a stator and to an electric machine. The slot lock comprises a first end region and a second end region, the first end region being configured to contact the first stator segment and the second stator segment at a radially inner limit, and the second end region being configured to contact the first stator segment and the second stator segment at a radially outer limit. Furthermore, the slot lock comprises a connecting region, which is designed to connect the first end region and the second end region in a cavity between the first stator segment and the second stator segment. In this case, the first end region and the second end region are sectioned by a common radial plane, the axis of rotation of the stator lying in the radial plane. Furthermore, the connecting region has at least one tolerance compensation region, which extends next to the radial axis.

Description

Technical Field

[0001] The invention relates to a slot lock for electrically insulating a first stator segment from a second stator segment of a stator, a stator and an electric machine. Background Art

[0002] The increasing use of electrical energy generated by regeneration and the increasing electrification, especially in mobile applications, and the trend towards autonomous driving all lead to a demand for increased efficiency and thus to an increase in the power density of electric machines. The components of more compact electric motor solutions must withstand higher mechanical and thermal loads than their older predecessors, but the requirements for torque characteristics, for noise that is as low as possible, for torque ripple that is no longer perceptible, and for a holding torque in the range of a few thousandths of the rated torque remain or even become equally stringent. Such high-power-density electric motors mostly use segmented stators, which, under the same requirements, can achieve a smaller overall length and a higher copper filling factor than a similar full cross-section. This has the disadvantage that the stator windings of adjacent stator segments are very close to each other, which can lead to leakage currents and voltage breakdown of adjacent stator windings for higher operating voltages (400 V, 800 V) as used in current electric vehicles. In order to prevent this, slot locks are pushed between the wound stator segments, which on the one hand insulate the windings from one another and are intended to block or at least extend possible paths for leakage currents. Especially for electric motors in which the ingress of electrically conductive media cannot be excluded, small gaps between the slot locks and adjacent geometric structures must additionally be closed by insulating drip resin in order to prevent possible leakage currents. However, this is only successful if the gap to be closed is not too large, because otherwise a capillary effect would occur, which would pull the drip resin fingers into the gap to be closed. Therefore, all the components involved must be manufactured with narrow tolerances, which is associated with high technical and economic expenditure.

[0003] It is desirable to have a groove lock which can compensate for greater tolerances of adjacent components without additional component outlay and without unacceptable assembly forces or excessive gaps occurring after installation. Summary of the invention

[0004] In contrast, the slot lock according to the invention for insulating a first stator segment from a second stator segment, having the features of claim 1, has the advantage that it has a low elastic stiffness in the radial direction and can thereby compensate for its own tolerances and also tolerances of adjacent components. The slot lock according to the invention thus enables reliable electrical insulation of adjacent stator segments from one another. This is achieved according to the invention by a slot lock for electrically insulating a first stator segment from a second stator segment, the slot lock comprising a first end region. The first end region is designed to contact the first stator segment and the second stator segment at a radially inner boundary. In addition, the slot lock comprises a second end region, which is designed to contact the first stator segment and the second stator segment at a radially outer boundary. In addition, the slot lock comprises a connecting region, which is designed to connect the first end region and the second end region in a cavity between the first stator segment and the second stator segment. The first end region and the second end region are intersected by a common radial plane, wherein the radial plane is oriented such that the rotation axis of the stator lies in the radial plane. In particular, the midpoint of the first and / or second end region is intersected by the radial plane. The connecting region has at least one tolerance compensation region extending beside the radial axis. The tolerance compensation region imparts radial flexibility to the connecting region of the slot lock with respect to tensile and compressive forces. As a result, the slot lock can compensate for tolerances of the stator and achieve a reliable insulation layer between two adjacent stator segments.

[0005] The groove lock is preferably made of plastic, in particular of polyamide. It is also possible to manufacture the groove lock from at least two different materials with different elastic moduli and thereby influence the elastic properties in a targeted manner.

[0006] The dependent claims describe preferred developments of the invention.

[0007] The connecting region is preferably thin-walled. In particular, the thickness of the connecting region perpendicular to the radial plane is smaller than the length of the slot lock parallel to the axis of rotation, preferably at least 10 times smaller. The thin-walled connecting region achieves improved flexibility in the radial direction and reduced material requirements.

[0008] Furthermore, the connection region is preferably formed such that the ratio of stress to strain in the connection region along a radial plane is smaller than the elastic modulus of the material of the connection region. This ensures that the flexibility of the connection region is high enough to compensate for tolerances of the stator.

[0009] Furthermore, the first end region and / or the second end region have lamellae, wherein one lamellae each protrude from the radial plane on both sides of the end region. In particular, the lamellae protrude orthogonally from the radial plane. The lamellae enable a flexible sealing of the slot lock relative to the inner and / or outer boundaries between two adjacent stator segments. The slot lock thus allows a medium, such as a coolant, to be introduced into the cavity. The first and second end regions can be reliably sealed with drip resin in the region of the lamellae and thus further prevent possible leakage currents.

[0010] The connecting region preferably has a curvature, which reliably and predictably absorbs forces and enables a high degree of flexibility in the radial direction.

[0011] Furthermore, the connecting region preferably has an S-shaped or meander-shaped structure. By juxtaposing a plurality of bends in the form of a meander-shaped structure, the flexibility can be further reduced and stator tolerances can be easily compensated and reliable electrical insulation of adjacent stator segments can be achieved.

[0012] In a preferred development of the invention, the connecting region has a geometrically hollow body. The hollow body preferably extends parallel to the rotation axis of the stator along the total length of the slot lock. It is also preferred that the hollow body has a box-shaped cross section with four or five corners. The axial ends of the geometrically hollow body can be open or closed. The geometrically hollow body is another possible solution for purposefully influencing the flexibility of the slot lock in the radial direction and ensuring reliable insulation for adjacent stator segments.

[0013] Preferably, the geometrically hollow body forms a part of the first end region and / or a part of the second end region. Thus, the geometrically hollow body can simultaneously achieve an increase in flexibility in the radial direction and a seal relative to the stator.

[0014] Furthermore, it is preferred that the first end region and / or the second end region is bisected and has a U-shaped partial region. In this case, the first end of the U-shaped partial region is provided for contacting the first stator segment and the second end of the U-shaped partial region is provided for contacting the second stator segment. The U-shaped partial region reduces the flexibility of the slot lock and at the same time allows contacting adjacent stator segments.

[0015] The connecting region preferably has a combination of the different flexibility geometries described above in order to selectively influence the elastic properties of the groove lock.

[0016] The invention further relates to a stator comprising a plurality of stator segments with concentrated windings. In this case, slot locks according to one of the above-described embodiments are arranged in cavities between adjacent stator segments. The stator with concentrated windings has a plurality of adjacent stator segments with different voltages. The slot locks enable a close arrangement of the stator segments next to each other, so that the filling factor of the stator and its power density can be increased.

[0017] The cavity between two adjacent stator segments of the stator is preferably set up for guiding a cooling fluid. As a result, the stator can be cooled and its efficiency can be increased. Here, the slot lock that divides the cavity into two parts can achieve electrical insulation between two adjacent stator segments.

[0018] Furthermore, the invention relates to an electric machine comprising a rotor and a stator as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the accompanying drawings:

[0020] Figure 1 shows a schematic diagram of a plurality of stator segments separated by slot locks according to a first embodiment;

[0021] Figure 2 shows a schematic diagram of a plurality of stator segments separated by slot locks according to a second embodiment;

[0022] Figure 3 shows a schematic diagram of a plurality of stator segments separated by slot locks according to a third embodiment; and

[0023] Figure 4 The diagram shows a schematic representation of a plurality of stator segments which are separated by slot locks according to a fourth exemplary embodiment. DETAILED DESCRIPTION

[0024] Figures 1 to 4 Three adjacent stator segments 21 , 22 of a stator 2 are shown, which are electrically insulated from one another by slot locks 1 according to different embodiments.

[0025] Figure 1 Also shown is an electric machine 4 which is designed as an internal rotor motor. The electric machine 4 has a rotor 5 which is arranged inside the stator 2. The rotor 5 and the stator 2 are arranged coaxially to one another and have a common axis of rotation XX which is arranged orthogonal to the plane of the drawing.

[0026] The stator 2 has a plurality of stator segments 21, 22 arranged around an axis of rotation XX. Each stator segment 21, 22 comprises an insulating mask 27 on which a winding 26 is placed. The insulating mask 27 preferably has a substantially H-shaped cross section, wherein the winding 26 is arranged around a central web and the end regions of the H-shaped cross section of different stator segments 21, 22 are aligned with one another. In this case, cavities 25 are formed between the windings 26 of adjacent stator segments 21, 22. The windings 26 are preferably controlled in such a way that adjacent stator segments 21, 22 have different voltages.

[0027] The slot lock 1 is arranged between the adjacent first stator segment 21 and the second stator segment 22. The slot lock 1 comprises a first end region 11, a second end region 12 and a connecting region 13. The connecting region 13 is arranged between the first end region 11 and the second end region 12. The connecting region 13 is thin-walled and has a constant thickness in the first embodiment. The first end region 11 and the second end region 12 are intersected by a radial plane RR. The radial plane RR is oriented so that the rotation axis XX lies on it.

[0028] The insulating mask 27 of the stator segments 21, 22 has a radial inner boundary 23 and a radial outer boundary 24 at the end regions of the H-shaped cross section. In this case, the first end region 11 is arranged at the radial inner boundary 23 and the second end region 12 is arranged at the radial outer boundary 24. The first end region 11 and the second end region 12 each have a lamella 15, which extends essentially perpendicularly from the radial plane RR and is adapted to the shape of the radial inner and outer boundaries 23, 24. As a result, the lamella 15 of the first and second end regions 11, 12 rest flush against the inner and outer boundaries 24 of the insulating mask 27, thereby enabling reliable sealing and electrical insulation of the slot lock 1. The sealing and electrical insulation can be further improved by using a drip resin, which flows between the lamella 15 and the inner and / or outer boundaries 23, 24 by capillary effect. As a result, it can be achieved that a cooling fluid can flow through the cavity 25 of the stator 2.

[0029] The connecting region 13 between the first and second end regions 11, 12 is designed in such a way that it has a tolerance compensation region 14 which extends beside the radial axis RR. Figure 1 In FIG. 1 , the tolerance compensation region 14 is designed in an S-shaped manner and has two bends 16 . The shape of the tolerance compensation region according to the invention thus allows radial flexibility with respect to tensile and compressive forces, thereby also making it possible to reliably compensate for temperature fluctuations of the stator 2 .

[0030] Figure 2A schematic partial view of a stator 2 with three adjacent stator segments 21 , 22 and a slot lock 1 according to a second exemplary embodiment is shown.

[0031] The second embodiment differs from the first embodiment in the shape of the connecting region 13. The connecting region 13 in the second embodiment has a meander-shaped structure 17 in cross section, which has a plurality of S-shaped sections.

[0032] The meander-shaped structure 17 of the connection region 13 is adapted to the shape of the cavity 25 with respect to the width of the S-shaped segments, so that the minimum distance to the winding 26 is constant. The connection region 13 of the slot lock 1 thus has an improved and uniform radial flexibility.

[0033] At half the height between the first end 31 and the second end 32 of the slot lock 1, the connecting region 13 has a straight region 19, which lies in the radial plane RR. The straight region 19 divides the connecting region 13 into a first meander-shaped structure 17 at the first end 31 and a second meander-shaped structure 17 at the second end 32. The straight region 19 has a greater thickness than the meander-shaped structure 17.

[0034] The turns of the meander-shaped structure 17 preferably intersect the radial plane RR orthogonally, so that the flexibility of the meander-shaped structure 17 in the radial direction is as high as possible.

[0035] Figure 3 A schematic partial view of a stator 2 with three adjacent stator segments 21 , 22 and a slot lock 1 according to a third exemplary embodiment is shown.

[0036] The third embodiment differs from the first and second embodiments in the shape of the connecting region 13. The connecting region 13 in the third embodiment has two geometrically hollow bodies 18, respectively.

[0037] The geometric hollow body 18 has a pentagonal cross section and extends along the axis of rotation XX. The dimensions of the geometric hollow body 18 are adapted to the cavity 25 between adjacent stator segments 21, 22. The pentagonal cross section of the geometric hollow body 18 is connected to the straight region 19 of the connecting region 13 via the sides on one side and via the corners on the other side, so that the sides are arranged perpendicular to the straight region 19.

[0038] A further geometric hollow body 18 is arranged on the second end region 12 of the groove lock 1 and is therefore part of both the second end region 12 and the connecting region 13 . In this case, two faces of the geometric hollow body 18 bear against the outer boundary 24 .

[0039] The two geometrically hollow bodies 18 are connected via a straight region 19 lying in a radial plane RR. Furthermore, the geometrically hollow body 18 is connected to the first end region 11 via the straight region 19. The vertical arrangement of the geometrically hollow body 18 at the straight region 19 increases the flexibility of the connection region. The thickness of the straight region 19 is greater than the wall thickness of the geometrically hollow body in order to increase the rigidity perpendicular to the radial plane RR.

[0040] Figure 4 A schematic partial view of a stator 2 with three adjacent stator segments 21 , 22 and a slot lock 1 according to a fourth exemplary embodiment is shown.

[0041] The fourth exemplary embodiment differs from the preceding exemplary embodiments in the shape of the connecting region 13. The connecting region 13 in the fourth exemplary embodiment has a U-shaped partial region 30 at the first end region 11.

[0042] The U-shaped partial region 30 of the fourth exemplary embodiment has a first end 31 and a second end 32, wherein the first end 31 contacts the first stator segment 21 at the inner limit 23 and the second end 32 contacts the second stator segment 22 at the inner limit 23. The U-shaped partial region thus enables both radial flexibility and tolerance compensation between the first stator segment 21 and the second stator segment 22 in the region of the first end region 11. The U-shaped partial region is preferably adapted to the shape of the cavity 25 between two adjacent stator segments 21, 22.

[0043] The U-shaped partial region 30 is connected to the second end 12 via the straight region 19. In this case, the straight region 19 is arranged perpendicularly to the U-shaped region 30. The straight region 19 has a greater length in the radial direction than the U-shaped region.

[0044] The ends 31, 32 of the U-shaped partial region 30 have a greater material thickness than other sections of the U-shaped partial region 30, in particular than the rest of the U-shaped partial region 30. The ends 31, 32 are adapted to the shape of the inner boundary 23 in order to achieve a secure seal relative to the cavity 25.

Claims

1. A slot lock (1) for electrically insulating a first stator segment (21) relative to a second stator segment (22) of a stator (2), comprising a first end region (11) which is designed to contact the first stator segment (21) and the second stator segment (22) at a radially inner boundary (23), a second end region (12) which is designed to contact the first stator segment (21) and the second stator segment (22) at a radially outer boundary (24), and a connecting region (13) which is designed to connect the first end region (11) and the second end region (12) in a cavity (25) between the first stator segment (21) and the second stator segment (22), wherein the first end region (11) and the second end region (12) are cut by a common radial plane (RR), wherein the rotation axis (XX) of the stator (2) lies in the radial plane (RR), and The connecting region (13) has at least one tolerance compensation region (14) extending alongside the radial axis (RR). 2 . The slot lock ( 1 ) according to claim 1 , wherein the connecting region ( 13 ) is thin-walled and is in particular designed as a plastic injection-molded part.

3. The slot lock (1) according to any one of the preceding claims, wherein the ratio of stress to strain of the connection region (13) along a radial plane (RR) is smaller than the elastic modulus of the material of the connection region (13).

4. A slot lock (1) according to any one of the preceding claims, wherein the first end region (11) and / or the second end region (12) each have two lamellae (15), wherein each lamella (15) extends from a radial plane (RR) on both sides of the end region (11, 12), in particular extending orthogonally to the radial plane (RR).

5. The slot lock (1) according to any one of the preceding claims, wherein the connecting region (13) has at least one bend (16).

6. The slot lock (1) according to claim 5, wherein the connecting area (13) has an S-shaped or meander-shaped structure (17).

7. Groove lock (1) according to any of the preceding claims, wherein the connecting region has a geometrically hollow body (18) in a section transversely to the RR axis.

8. The groove lock (1) according to claim 7, wherein the geometrically hollow body (18) forms a part of the first end region (11) and / or a part of the second end region (12).

9. A slot lock (1) according to any one of the preceding claims, wherein the first end region (11) and / or the second end region (12) is divided into two halves and has a U-shaped or Y-shaped partial region (30), wherein the first end (31) of the U-shaped or Y-shaped partial region (30) is established for contacting the first stator segment (21), and wherein the second end (32) of the U-shaped partial region (30) is established for contacting the second stator segment (22).

10. A stator (2) comprising a plurality of stator segments (21, 22) with concentrated windings (26), wherein a slot lock (1) according to any one of the preceding claims is arranged in a cavity (25) between adjacent stator segments (21, 22). 11 . The stator ( 2 ) according to claim 10 , wherein the cavity ( 25 ) between two adjacent stator segments ( 21 , 22 ) is designed for conducting a cooling fluid.

12. An electric machine (4) comprising a rotor (5) and a stator (2) according to claim 10 or 11.

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