Electric machine rotor of an at least partially electrically drivable motor vehicle, electric machine and drive train of an at least partially electrically drivable motor vehicle

Abstract

Rotor for an electric machine of an at least partially electrically drivable motor vehicle, electric machine and drive train for an at least partially electrically drivable motor vehicle. The invention relates to a rotor (10) for an electric machine of an at least partially electrically drivable motor vehicle, wherein the rotor (10) comprises a plurality of radially spaced recesses (12) for structuring a magnetic flux barrier, and wherein the recesses (12) are divided into a plurality of recess regions (22) by one or more internal webs (20), and wherein the web thickness (24) of the internal webs (20) closer to the rotor center (16) is greater than the web thickness (24) of the internal webs (20) further away from the rotor center (16). Furthermore, the invention relates to an electric machine comprising the aforementioned rotor (10). Furthermore, the invention relates to a drive train for an at least partially electrically drivable motor vehicle, which has an electric machine or the aforementioned rotor (10).

Description

Technical Field

[0001] The present invention relates to a rotor for an electric motor for at least a partially electrically driven motor vehicle, wherein the rotor includes a plurality of radially spaced grooves for constructing a magnetic flux barrier, and wherein the grooves are divided into a plurality of groove regions by one or more internal tabs.

[0002] Furthermore, the present invention relates to an electric motor including the aforementioned rotor and a stator.

[0003] Furthermore, the present invention relates to a drive system for at least partially electrically driven motor vehicles, the drive system having the aforementioned motor or the aforementioned rotor. Background Technology

[0004] In a pure synchronous reluctance motor, the rotor torque is caused by magnetic reluctance, and not by the Lorentz force as in other motors. In other words, rotational motion is thus similar to that generated by the stator in a permanent magnet motor, except that the rotor of a pure synchronous reluctance motor does not contain magnets, and instead its magnetic force is generated by the induced stator field. To this end, different permeabilities are provided by the rotor geometry, which reflects the corresponding pole pairs of the rotor, thus the rotor includes grooves for constructing magnetic flux barriers.

[0005] Typically, the rotor for a synchronous reluctance motor has a lamination assembly made of soft magnetic material, wherein individual electromagnetic laminations with corresponding lamination cross-sectional geometries are stacked on top of each other along the axial direction. To construct at least one pole pair, the rotor includes flux-barrier sections and corresponding flux-conducting sections, which are distinguished from each other by different permeabilities. The section with higher permeability is designated as the d-axis of the rotor, and the section with relatively lower permeability is designated as the q-axis.

[0006] This is typically achieved by constructing multiple air-filled grooves within a soft magnetic material, thereby suppressing magnetic flux and thus reducing permeability. For stability reasons, the grooves can be divided into multiple groove regions by internal tabs. The arrangement of the tabs improves the strength of the lamination assembly, which in particular optimizes rotor stability during operation. However, the tabs affect the permeability and correspondingly influence the permeability ratio between the d-axis and q-axis, which may adversely affect the motor's efficiency.

[0007] Furthermore, pure synchronous reluctance motors have low starting torque. This problem can be addressed by using additional magnets in the rotor. These additional magnets are typically placed in the air region formed by grooves. Introducing magnets into the grooves or a portion of the grooves can also affect the magnetic characteristics of the rotor. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a rotor for an electric motor having improved magnetic properties, higher mechanical stability and / or a longer service life.

[0009] The solution of the present invention is achieved by a rotor of an electric motor for at least a partially electrically driven motor vehicle having the features of claim 1, an electric motor according to claim 14, and a drive system for at least a partially electrically driven motor vehicle according to claim 15. Preferred embodiments of the invention are described in the dependent claims, the specification, and / or the drawings, wherein, unless the contrary is explicitly stated in the context, additional features described or shown in the dependent claims, the specification, or the drawings can individually or in any combination represent the subject matter of the invention.

[0010] According to the invention, a rotor for an electric motor of at least partially electrically driven motor vehicle is provided, wherein the rotor includes a plurality of radially spaced grooves for constructing a magnetic flux barrier, wherein the grooves are divided into a plurality of groove regions by one or more internal tabs, and wherein the tab thickness of the internal tab closer to the rotor center is greater than the tab thickness of the internal tab further away from the rotor center.

[0011] Therefore, one aspect of the invention is that the inner laminations have different lamination thicknesses, with the inner laminations closer to the rotor center having a greater thickness than those farther from the rotor center. In this way, centrifugal force is better absorbed by the rotor and preferably by the lamination assembly during rotor operation, resulting in higher mechanical load capacity. Based on the improved mechanical load capacity, the lamination thickness can be smaller, thereby improving the rotor's magnetic permeability.

[0012] Preferably, the rotor comprises one or more pole pairs. The rotor advantageously has an even number of poles, particularly two, four, or six, and especially preferably six, i.e., three pole pairs. The rotor is preferably made of a soft magnetic material, such as electromagnetic laminations, in which individual electromagnetic laminations having corresponding lamination cross-sectional geometries are stacked on top of each other in the axial direction. To construct at least one pole pair, the rotor includes flux-blocking sections and corresponding flux-conducting sections, which are distinguished from each other by different intensities of permeability. The flux barrier is implemented by grooves.

[0013] Preferably, multiple radially spaced grooves have a U-shaped profile. In this document, a U-shaped, crescent-shaped, or arc-shaped profile is understood as the profile of a groove that begins at the outer periphery of the rotor, extends toward the center of the rotor with increasing curvature, and then extends toward the outer periphery of the rotor again with decreasing curvature at the apex where the groove has its maximum curvature.

[0014] By using internal plates closer to the rotor center with greater plate thickness compared to internal plates further away from the rotor center, and with the accompanying improved mechanical stability in the case of improved magnetic properties, the rotor can operate under higher loads, thereby extending the operating range of the motor.

[0015] Preferably, the rotor comprises a plurality of sector segments, and each sector segment has at least two, preferably three, radially spaced grooves. The rotor preferably comprises six sector segments, each having at least two, preferably three, grooves radially spaced. Preferably, each groove in a sector segment is divided into multiple groove regions by internal tabs.

[0016] The U-shaped or arcuate grooves are further preferably configured to have a mirror-symmetric structure with a mirror axis extending radially through the center of the rotor. Preferably, each sector segment thus has a mirror-symmetric structure, wherein the mirror axis extends radially from the center of the rotor and divides the sector segment in half. Preferably, the apex of the groove is located on the mirror axis.

[0017] According to a preferred embodiment of the invention, the thickness of all internal laminations depends on the distance of the respective internal lamination from the rotor center and decreases as the distance from the rotor center increases. This enables particularly good absorption of centrifugal force into the rotor laminations, allowing the internal laminations to be designed with a small overall thickness, thereby giving the rotor good magnetic properties.

[0018] According to a preferred embodiment of the invention, the inner tab has a shape that is recessed on at least one side. Here, the recessed shape refers to an inner tab that separates two recessed regions from each other, having a curvature at least relative to one of these two recessed regions, causing the tab to arch inward. Therefore, the material thickness of the tab in the starting and ending regions is preferably greater than the material thickness in the middle region. This embodiment, with its at least one-sided recess, achieves high strength and a thin tab thickness, resulting in good magnetic properties for the rotor. The other side of the tab can be made flat.

[0019] According to another preferred embodiment of the invention, the internal tab is configured to have a recessed shape on both sides. In other words, it is therefore preferred that both sides of the tab be recessed. This enables the achievement of a particularly small tab thickness.

[0020] According to a preferred embodiment of the invention, a portion of the groove region is filled with a magnetic filler material. The magnetic filler material can be designed as a plastic material with magnetic particles. Preferably, the magnetic particles are permanent magnet particles. In other words, the magnetic filler material is thus preferably a permanent magnet disposed in the rotor.

[0021] In this regard, according to another preferred design, the internal tab separating the recessed area without filling material from the recessed area filled with magnetic filling material is designed to be more sharply recessed towards the recessed area without filling material compared to the recessed area constructed with filling material. This allows for an internal tab having one flat side and one recessed side. Alternatively, a tab with two recessed sides having two different intensities of curvature can be used. The smaller curvature of the side of the internal tab facing the recessed area constructed with filling material reduces demagnetization of the magnet, as the magnet is more sharply positioned towards the rotor periphery.

[0022] According to a preferred embodiment of the invention, the internal tabs divide the groove into an odd number of groove regions. The groove is preferably divided into an odd number of groove regions by the internal tabs, wherein each groove preferably has at least three or five groove regions. Because the number is odd, a central groove region is obtained, which is preferably arranged on a mirror axis.

[0023] In this respect, according to a preferred improvement of the invention, the central recessed region is not filled with material, and recessed regions filled with magnetic filler material are provided on both sides of the central recessed region. The central recessed region—the third recessed region in the case of five recessed regions—is therefore unfilled. In other words, this recessed region is thus designed as an air region. Furthermore, recessed regions filled with magnetic filler material are provided on both sides of the central recessed region.

[0024] According to another preferred embodiment of the invention, the central groove region has two opposing sides extending circumferentially along the rotor, with the side closer to the rotor center having a curvature along the rotor's circumferential direction. The curvature of the side of the central groove closer to the rotor center particularly enables the uniform heat-fitting of the rotor laminations onto the shaft, thereby achieving a press fit. This reduces the risk of localized bulging of the lamination assembly during operation at high rotor speeds.

[0025] According to another preferred embodiment of the invention, the central groove region has a trapezoidal basic shape, wherein two parallel sides of the basic shape extend substantially tangentially to the circumferential direction of the rotor, and wherein the longer of the two parallel sides of the basic shape is closer to the rotor center. Here, the basic shape refers to an abstract and / or simplified form of the effective shape of the groove. The effective shape of the groove then deviates from the basic shape, for example, by rounding corners and / or curvature in the edges. "Substantially tangential" means that the sides of the basic shape extend tangentially by ±10 degrees. In other words, it is therefore preferred that the central groove region gradually narrows towards the outer periphery of the rotor along the radial axis. This produces a favorable field force line orientation. The gradual narrowing of the groove region results in the inner tabs dividing the groove extending substantially radially, or having a radial component, thereby improving the absorption of centrifugal force into the lamination assembly during rotor operation. Due to the improved mechanical load-bearing capacity, the width of the inner tabs can be smaller, thereby improving the magnetic permeability of the rotor.

[0026] Particularly preferred is the central groove region having the basic trapezoidal shape described above and / or having the central groove region of the circumferential curvature described above on the sides, which is the central groove region of the groove arranged closest to the center of the rotor.

[0027] According to another preferred improvement of the invention, the outermost groove region is unfilled and located next to the groove region filled with magnetic filler material. The outermost groove region is thus also preferably unfilled and located next to the groove region filled with magnetic filler material.

[0028] In other words, it is also preferable to position the two air regions on either side of the groove region filled with magnetic filler material. This arrangement achieves an improved field distribution, thereby preventing demagnetization of the groove region filled with magnetic filler material during motor operation in an effective manner. Furthermore, the rotor exhibits improved reluctance torque.

[0029] According to another preferred embodiment of the invention, the outermost groove region has a trapezoidal basic shape, wherein two parallel sides of the basic shape extend substantially tangentially to the circumferential direction of the rotor, and wherein the longer of the two parallel sides of the basic shape is closer to the rotor center. "Substantially tangential" means that the sides of the basic shape extend tangentially by ±10 degrees. This results in favorable guidance of the field lines.

[0030] According to another preferred embodiment of the invention, the two outermost groove regions of the corresponding grooves are each spaced apart from the outer periphery of the rotor by an external tab. Preferably, the thickness of the external tab remains constant on the outer periphery of the rotor.

[0031] According to another preferred improvement of the invention, the radial spacing between two adjacent grooves remains constant at ±5% for all grooves. This also results in a favorable field distribution, in which, on the one hand, the torque generated by the groove regions filled with magnetic filling material can be improved, and on the other hand, the reluctance torque of the rotor can be improved.

[0032] Furthermore, the present invention relates to an electric motor having the aforementioned rotor and a stator. The rotor is preferably arranged on a shaft inside a hollow cylindrical stator. Preferably, the motor is designed as a synchronous reluctance motor.

[0033] Regarding the stator, according to a preferred improvement of the invention, the stator comprises a ring-shaped yoke having an inner side pointing radially inward, wherein a plurality of stator teeth spaced apart from each other in the circumferential direction of the yoke are arranged on the inner side of the yoke. Preferably, the rotor and stator of the motor are fitted together such that the outermost recessed region of the rotor is adapted to the distance between two spaced stator teeth in terms of its circumferential spacing relative to each other.

[0034] The stator is therefore preferably a yoke with a ring-shaped structure. Typically, the yoke is formed from multiple ring-shaped, stamped laminations arranged sequentially and connected to each other along the axial direction of the stator. The laminations can be joined by stamping, bonding, and / or welding. The yoke preferably has an inner side on its radially inward-pointing side. A plurality of stator teeth are arranged at least in a form-locking manner on the inner side, wherein the stator teeth are spaced apart from each other along the circumferential direction of the yoke. Preferably, each stator tooth is constructed as a single tooth. The spacing between the stator teeth relative to each other along the circumferential direction of the yoke is preferably uniform and / or regular.

[0035] A continuous stator winding with a mat structure is preferably arranged between the stator teeth. This mat-structured continuous stator winding can also be referred to as a shaped wire winding. The mat-structured continuous stator winding preferably has electrical conductors for at least three phases (U, V, W). This allows the generation of the rotational magnetic field necessary for motor operation.

[0036] Furthermore, the aforementioned objective is achieved by a drive system for at least partially electrically driven motor vehicles, the drive system having either the aforementioned motor or the aforementioned rotor. The use of the rotor according to the invention in the motor particularly enables an expansion of the motor's operating range, and thus opens up the feasibility of operating a drive system for at least partially electrically driven motor vehicles under increased loads. Attached Figure Description

[0037] The present invention will be further explained below with reference to the accompanying drawings, wherein one or more features of the drawings can constitute features of the present invention on their own or in combination. Furthermore, the drawings are merely exemplary and not restrictive. Wherein: Figure 1 A rotor according to a preferred embodiment of the invention is illustrated schematically. Detailed Implementation

[0038] exist Figure 1 The image schematically illustrates a rotor 10 according to a preferred embodiment of the invention. The rotor 10 has a plurality of radially spaced grooves 12 for constructing magnetic flux barriers. Herein, three grooves 12 are arranged radially spaced apart in fan-shaped segments of the rotor 10, wherein the rotor 10 is formed by a total of six fan-shaped segments. In this embodiment, the grooves 12 have a U-shaped profile, wherein the grooves 12 begin at the outer periphery 14 of the rotor, extend towards the rotor center 16 with increasing curvature, and then extend again towards the outer periphery 14 of the rotor with decreasing curvature at the apex 18 where the groove 12 has its maximum curvature.

[0039] like Figure 1 As can be seen, the groove 12 is divided into multiple groove regions 22 by multiple internal tabs 20. In this paper, the four internal tabs 20 divide the groove 12 into five groove regions 22 respectively.

[0040] In the rotor 10, the thickness 24 of the inner tab 20 closer to the rotor center 16 is greater than the thickness 24 of the inner tab 20 further away from the rotor center 16.

[0041] Furthermore, in this embodiment, a portion of the groove region 22, specifically groove region 22a, is filled with a magnetic filling material, while groove region 22b is not filled and is designed as an air region. Figure 1 As can be seen, among the five groove regions 22 of the corresponding groove 12, the central groove region 22b (i.e., the groove region closest to the rotor center 16 among the five groove regions 22) and the two outermost groove regions 22b (which are respectively closest to the rotor outer periphery 14 among the five groove regions 22) are designed as air regions. Conversely, the remaining groove regions 22b are filled with magnetic filling material.

[0042] In addition, the rotor 10 is provided with an inner tab 20 having a shape with recesses on both sides. The inner tab 20 thus has curvature relative to the two recessed regions 22 (which the inner tab separates from each other), so that the material thickness of the inner tab 20 is greater in the starting and ending regions than in the middle region of the inner tab 20.

[0043] like Figure 1As can also be seen, the central groove region 22b has a trapezoidal basic shape 26, wherein the two opposing parallel sides 28, 30 of the basic shape extend tangentially to the circumferential direction of the rotor 10, and wherein the longer side 28 of the two parallel sides 28, 30 of the basic shape 26 is closer to the rotor center 16. The central groove region 22b thus gradually narrows toward the outer periphery 14 of the rotor. It can also be seen that the side 32 of the groove 22b closer to the rotor center 16 has a curvature along the circumferential direction of the rotor 10.

[0044] The two outermost groove regions 22b also have a trapezoidal basic shape 26, wherein the two parallel sides 28, 30 of the basic shape 26 extend substantially tangentially to the circumferential direction of the rotor 10, and wherein the longer side 28 of the two parallel sides 28, 30 of the basic shape is closer to the rotor center 16.

[0045] List of reference numerals in the attached diagram: 10 rotors 12 grooves 14 Rotor outer periphery 16 Rotor Center 18 vertices 20 Internal splicing 22. Recessed area 24mm thickness of splice 26. The basic shape of a trapezoid 28. The longer side of the basic shape 30. The shorter side of the basic shape 32. Side of the groove area.

Claims

1. A rotor (10) for an electric motor in a motor vehicle that is at least partially electrically driven, wherein, The rotor (10) includes a plurality of radially spaced grooves (12) for constructing a magnetic flux barrier, wherein the grooves (12) are divided into a plurality of groove regions (22) by one or more internal tabs (20). Its features are, The thickness (24) of the inner tab (20) closer to the rotor center (16) is greater than the thickness (24) of the inner tab (20) further away from the rotor center (16).

2. The rotor (10) according to claim 1, wherein, The thickness (24) of all internal tabs (20) depends on the distance between the corresponding internal tab (20) and the rotor center (16) and decreases as the distance to the rotor center (16) increases.

3. The rotor (10) according to any one of the preceding claims, wherein, The internal tab (20) has a shape with at least one side recessed.

4. The rotor (10) according to any one of the preceding claims, wherein, The internal tab (20) has a shape with recesses on both sides.

5. The rotor (10) according to any one of the preceding claims, wherein, A portion of the groove region (22a) is filled with magnetic filler material.

6. The rotor (10) according to claim 5, wherein, For the internal tab (20) that separates the recessed area (22b) without filling material from the recessed area (22a) filled with magnetic filling material, the recessed area (22b) without filling material is designed to be more drastically recessed compared to the recessed area (22a) constructed with filling material.

7. The rotor (10) according to any one of the preceding claims, wherein, The internal tabs (20) divide the groove (12) into an odd number of groove regions (22).

8. The rotor (10) according to claim 7, wherein, The central groove area (22b) is not filled with material, and there are groove areas (22a) on both sides of the central groove area (22b) filled with magnetic filling material.

9. The rotor (10) according to claim 7 or 8, wherein, The central groove region (22b) has two opposing sides (32) extending in the circumferential direction of the rotor (10), wherein the side (32) closer to the center (16) of the rotor has a curvature in the circumferential direction of the rotor (10).

10. The rotor (10) according to any one of claims 7 to 9, wherein, The central groove region (22b) has a trapezoidal basic shape (26), wherein the two parallel sides (28, 30) of the basic shape (26) extend substantially tangentially to the circumferential direction of the rotor (10), and wherein the longer side of the two parallel sides (28, 30) of the basic shape (26) is closer to the center of the rotor (16).

11. The rotor (10) according to any one of claims 7 to 10, wherein, The central groove region (22b) is the central groove region (22b) of the groove (12) arranged closest to the rotor center (16).

12. The rotor (10) according to any one of claims 7 to 11, wherein, The outermost groove area (22b) is without filling material and is located next to the groove area (22a) filled with magnetic filling material.

13. The rotor (10) according to any one of claims 7 to 12, wherein, The outermost groove region (22b) has a trapezoidal basic shape (26), wherein the two parallel sides (28, 30) of the basic shape (26) extend substantially tangentially to the circumferential direction of the rotor (10), and wherein the longer side of the two parallel sides (28, 30) of the basic shape (26) is closer to the rotor center (16).

14. An electric motor having a rotor (10) according to any one of the preceding rotor claims and having a stator.

15. A drive system for at least partially electrically driven motor vehicles, the drive system having an electric motor according to the preceding claims or having a rotor according to any one of the preceding rotor claims (10).

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