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 for an electric machine of an at least partially electrically drivable motor vehicle, the rotor comprising a plurality of radially spaced recesses for structuring a magnetic flux barrier, the recesses extending U-shaped from the outer circumference of the rotor towards the center of the rotor to a vertex and back to the outer circumference of the rotor, the recesses being divided by inner webs into an odd number of recess areas, wherein the middle recess area and the two outermost recess areas of the recesses are each free of filling material, and there are at least one recess area filled with a magnetic filling material between the middle recess area and the outermost recess areas. Furthermore, the invention relates to an electric machine comprising the aforementioned rotor. Furthermore, the invention relates to a drive train for an at least partially electrically drivable motor vehicle, the drive train having an electric machine or the aforementioned rotor.

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, wherein the grooves extend in a U-shape from the outer periphery of the rotor toward the center of the rotor to a apex and back to the outer periphery of the rotor, wherein the grooves are divided into an odd number of groove regions by internal tabs.

[0002] Furthermore, the present invention relates to an electric motor comprising the aforementioned rotor and 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 10, and a drive system for at least a partially electrically driven motor vehicle according to claim 12. 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 a 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 extend in a U-shape from the outer periphery of the rotor toward the center of the rotor to a apex and back to the outer periphery of the rotor, wherein the grooves are divided into an odd number of groove regions by internal tabs, wherein a central groove region and two outermost groove regions are respectively without filling material, and there is at least one groove region filled with magnetic filling material between the central groove region and the outermost groove regions.

[0011] Therefore, one aspect of the invention is to provide a plurality of radially spaced grooves that extend in a U-shape. The U-shaped, crescent-shaped, or arc-shaped course is understood herein to mean that the groove 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.

[0012] The groove is divided into an odd number of groove regions by internal tabs, wherein preferably each groove has at least five groove regions. The middle groove region—the third groove region in the case of five groove regions—and the two outermost groove regions—the first and fifth groove regions in the case of five groove regions—are each without filling material. In other words, these groove regions are thus designed as air regions. Furthermore, at least one groove region filled with magnetic filling material is provided between the middle groove region and the outermost groove region of the respective groove.

[0013] An improved field distribution is achieved through the described layout with two external air regions and a central air region, thereby preventing demagnetization of the groove regions filled with magnetic filling material during motor operation in an effective manner. Furthermore, the rotor exhibits improved reluctance torque.

[0014] Correspondingly, the rotor can operate under higher loads, thereby extending the operating range of the motor. Furthermore, the described layout with two external air regions and a central air region simplifies rotor manufacturing because the magnetization of the grooved regions filled with filler material is particularly simplified due to the improved field distribution.

[0015] 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 preferably a permanent magnet arranged in the rotor.

[0016] According to another preferred embodiment of the invention, 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 eight, i.e., four pole pairs. The rotor is preferably made of a soft magnetic material, such as electromagnetic laminations, in that 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 barrier sections and corresponding flux conduction sections, which are distinguished from each other by different permeabilities. The flux barrier is achieved by a U-shaped groove extending from the outer periphery of the rotor toward the center of the rotor to the apex of the U-shape and returning to the outer periphery of the rotor.

[0017] In this respect, according to a preferred improvement of the invention, the rotor comprises a plurality of sector segments, each sector segment having at least two, preferably at least three, radially spaced grooves. The rotor preferably comprises eight sector segments, each sector segment having at least two, preferably three or four U-shaped, radially spaced grooves. Preferably, each groove in the sector segment is divided into an odd number of groove regions by internal tabs, and more precisely, preferably into five groove regions each.

[0018] Regarding the U-shaped or arcuately extending grooves, according to another preferred improvement of the invention, the grooves have a mirror-symmetric structure with a mirror axis extending radially through the center of the rotor. Preferably, each sector segment has a mirror-symmetric structure, wherein the mirror axis extends radially from the center of the rotor and divides the sector segment into two halves. Preferably, the apex of the groove is located on the mirror axis.

[0019] According to another preferred embodiment of the invention, the groove has a hyperbolic trajectory. It has been shown that the hyperbolic trajectory of the groove results in particularly good magnetic flux conduction characteristics and corresponding motor efficiency.

[0020] Regarding the groove, according to another preferred improvement of the invention, the groove gradually narrows in width from the apex toward the outer periphery of the rotor. Along the extension direction of the U-shape from the apex toward the outer periphery of the rotor, the groove thus preferably becomes narrower in width, or in other words, the groove has its maximum width at the apex. As a result, the field flux can be targeted and become more concentrated, thereby enabling high efficiency of the motor.

[0021] In principle, it is feasible to keep the radial spacing at the apex between two adjacent U-shaped grooves constant for all grooves. However, according to a preferred improvement of the invention, the radial spacing at the apex between two adjacent U-shaped grooves decreases as the distance from the rotor center increases. The grooves are thus adapted to the magnetic field lines generated by the stator in the rotor. In this way, ideal magnetic flux conduction is established in the rotor's magnetic q-axis, and the ratio between the rotor inductance of the d-axis and the rotor inductance of the q-axis is selectively set. This improves both the torque generated by the groove regions filled with magnetic filling material and the rotor's reluctance torque.

[0022] According to another preferred improvement of the invention, at least the central groove region and / or the groove region filled with magnetic filler material are configured such that they gradually narrow towards the outer periphery of the rotor along an axis perpendicular to the extension direction of the U-shape. In the central groove region, the axis perpendicular to the extension direction of the U-shape corresponds to a radial axis. Particularly preferred is that the central groove region thus has a trapezoidal basic shape, wherein the two parallel sides of the basic shape extend 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. In the groove region filled with magnetic filler material, the axis perpendicular to the extension direction of the U-shape corresponds to an axis that extends substantially radially at a point near the rotor center, and has a larger tangential component due to the U-shaped trend of the groove as it moves further away from the rotor center. This produces a favorable trend of field force lines. The gradual narrowing of the groove region results in the internal laminations dividing the groove extending substantially radially or having a radial component, thereby achieving improved absorption of centrifugal force into the lamination assembly during rotor operation. Due to the improved mechanical load-bearing capacity, the width of the internal contacts can be very small, thereby improving the magnetic conductivity of the rotor.

[0023] According to another preferred improvement of the invention, a plurality of spaced-apart grooves have internal tabs extending along a preferred common extending direction, wherein the extending direction has its origin at the intersection of the mirror axis and the rotor periphery and extends toward the rotor center at an angle of less than 90 degrees to the mirror axis. In other words, the plurality of radially spaced grooves are preferably divided by the plurality of internal tabs into adjacent areas in the shape of cake slices, wherein the tips of the respective cake slices are located at the intersection of the mirror axis and the rotor periphery. Therefore, the groove area of ​​the groove near the rotor center is longer along the U-shaped extending direction than the corresponding groove area of ​​the groove near the rotor periphery.

[0024] According to a further preferred embodiment of the invention, the two outermost groove regions of the corresponding grooves are respectively spaced apart from the outer circumference of the rotor by external tabs. Preferably, the thickness of the external tabs remains constant on the outer circumference of the rotor.

[0025] In other words, the outermost groove region of the plurality of grooves is preferably provided such that the outermost groove region of the groove near the rotor center is longer along the U-shaped extension direction than the outermost groove region of the groove near the rotor periphery. This particularly improves the demagnetizing characteristics of the groove region arranged between the central groove region and the outermost groove region and filled with magnetic filling material.

[0026] According to a further preferred embodiment of the invention, the recessed area filled with magnetic filler material is designed to extend along magnetic field lines generated by the stator during motor operation. This approach enables the generation of high-performance motors.

[0027] Furthermore, the present invention relates to an electric motor having the aforementioned rotor and stator. The rotor is preferably arranged on a shaft inside a hollow cylindrical stator. Preferably, the motor is designed as a synchronous reluctance motor.

[0028] 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.

[0029] 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. On the inner side, a plurality of stator teeth are arranged in a form-locking manner, 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.

[0030] A corrugated or continuous stator winding with a mat structure is preferably arranged between the stator teeth. The continuous stator winding with a mat structure can also be referred to as a shaped wire winding. The continuous stator winding with a mat structure preferably has electrical conductors for at least three phases (U, V, W). This allows the generation of the rotational magnetic field necessary for the operation of the motor.

[0031] 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

[0032] 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 The cross-section of a rotor according to a preferred embodiment of the invention is schematically shown. Figure 2 A cross-section of an electric motor comprising a rotor according to a preferred embodiment of the invention is shown schematically. Detailed Implementation

[0033] exist Figure 1 The diagram schematically illustrates a sector segment of rotor 10 according to a preferred embodiment of the invention. Rotor 10 consists of a total of eight such sectors. Figure 1 The sector segment shown is formed. Each sector segment has multiple radially spaced grooves 12 for constructing a flux barrier. In this document, four grooves 12 are arranged radially spaced apart from each other in the sector segment of the rotor 10.

[0034] The groove 12 has a U-shaped profile, wherein the groove 12 begins at the outer periphery 14 of the rotor and extends toward the center 16 of the rotor with increasing curvature, so that at the apex 18 where the groove 12 has its maximum curvature, it extends again toward the outer periphery 14 of the rotor with decreasing curvature.

[0035] like Figure 1 As can be seen, the groove 12 is divided into an odd number of 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. In the rotor 10, the middle groove region 22a and the two outermost groove regions 22b of the groove 12 are respectively without filling material, and there is at least one groove region 22c filled with magnetic filling material between the middle groove region 22a and the outermost groove region 22b.

[0036] In the rotor 10 described herein, the groove 12 is configured with a mirror-symmetric structure, such that the central groove region 22a is located on the mirror axis 24. Similarly, the vertices 18 of the groove are located on the mirror axis 24.

[0037] Starting from the apex of each groove 12 and moving towards the outer periphery 14 of the rotor, the grooves gradually narrow in width 26. For example... Figure 1 As exemplarily shown at two locations, the width 26 of the groove region 22c (measured as an extension perpendicular to the U-shaped trend of the groove region 22c) is thus larger at the location near the rotor center 16 than at the location near the rotor outer periphery 14.

[0038] Furthermore, it can be seen that the central groove region 22a and the groove region 22c filled with magnetic filling material also gradually narrow towards the outer periphery 14 of the rotor along the axis 28 perpendicular to the extension direction of the U-shape. For the central groove region 22a, the axis 28 corresponds to the mirror axis 24.

[0039] In addition, such as Figure 1 As can be seen, the internal tabs 20 of the multiple spaced-apart grooves 12 extend along a common extending direction 30, which has its origin at the intersection 32 of the mirror axis 24 and the outer periphery of the rotor 14. For the internal tabs 20 that separate the middle groove region 22a from the groove region 22c, the common extending direction 30 extends toward the rotor center 16 at an angle of about 5 degrees, and for the internal tabs 20 that separate the groove region 22c from the outermost groove region 22b, the common extending direction 30 extends toward the rotor center 16 at an angle of about 60 degrees.

[0040] Figure 2 A cross-section of an electric motor 34, including a rotor 10 and a stator 36, is schematically shown. The rotor 10 is similar to... Figure 1The rotor 10 in the paper has a different construction, which is discussed in this paper. Figure 2 The rotor 10 in the rotor has only three grooves 12 in the sector segment (instead of four). Furthermore, the grooves 12 are shaped such that the radial spacing 38 between two adjacent U-shaped grooves 12 at the apex 18 decreases as the distance from the rotor center 16 increases.

[0041] Furthermore, the recessed region 22c, filled with magnetic filler material, is designed to extend along magnetic field lines generated by the stator 36 during the operation of the motor 34. In this respect, the stator 36 has a ring-shaped yoke with a plurality of stator teeth 40 spaced apart from each other in the circumferential direction of the yoke arranged on its radially inwardly pointing inner side. Stator windings 42 are arranged between the stator teeth 40. The stator windings 42 have electrical conductors for generating the magnetic field. Furthermore, the outermost recessed region 22b of the rotor 10 is adapted to the distance between two adjacent stator teeth 40 in terms of its circumferential spacing relative to each other.

[0042] 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 22a Central recessed area, air area 22b The outermost recessed area, air area 22c Recessed area filled with magnetic filler material 24 Mirror Axis 26 width 28. The axis perpendicular to the extension direction of the U-shape of the groove. 30. Common extension direction of internal splices 32. Intersection of the mirror axis and the outer periphery of the rotor 34 motors 36 stators 38. Radial spacing between grooves 40 stator teeth 42. Stator winding.

Claims

1. A rotor (10) for an electric motor (34) of at least a partially electrically driven motor vehicle, wherein, The rotor (10) includes a plurality of radially spaced grooves (12) for constructing a magnetic flux barrier, wherein the grooves (12) extend in a U-shape from the outer periphery (14) of the rotor toward the center (16) of the rotor to a apex (18) and back to the outer periphery (14) of the rotor, wherein the grooves (12) are divided into an odd number of groove regions (22) by internal tabs (20). Its features are, The central groove region (22a) and the two outermost groove regions (22b) of the groove (12) are not filled with material, and there is at least one groove region (22c) filled with magnetic filling material between the central groove region (22a) and the outermost groove region (22b).

2. The rotor (10) according to claim 1, wherein, The rotor (10) includes a plurality of sector segments, and each sector segment has at least two, preferably at least three, radially spaced grooves (12).

3. The rotor (10) according to any one of the preceding claims, wherein, The groove (12) has a mirror-symmetric structure with a mirror axis (24), and the mirror axis (24) extends radially through the rotor center (16).

4. The rotor (10) according to any one of the preceding claims, wherein, The groove (12) has a hyperbolic curve.

5. The rotor (10) according to any one of the preceding claims, wherein, The groove (12) starts from the vertex (18) and gradually narrows in width (26) towards the outer periphery (14) of the rotor.

6. The rotor (10) according to any one of the preceding claims, wherein, The radial spacing (38) between two adjacent U-shaped grooves (12) at the apex (18) decreases as the distance from the rotor center (16) increases.

7. The rotor (10) according to any one of the preceding claims, wherein, At least the central groove region (22a) and / or the groove region (22c) filled with magnetic filling material gradually narrows toward the outer periphery (14) of the rotor along an axis perpendicular to the extension direction of the U-shape.

8. The rotor (10) according to claim 3, wherein, The internal tabs (20) of a plurality of spaced-apart grooves (12) extend along a preferred common extension direction (30), wherein the extension direction (30) has its origin at the intersection (32) of the mirror axis (24) and the outer periphery of the rotor (14) and extends toward the center of the rotor (16) at an angle of less than 90 degrees to the mirror axis (24).

9. The rotor (10) according to any one of the preceding claims, wherein, The groove region (22c) filled with magnetic filling material is designed to extend along magnetic field lines generated by the stator (36) during the operation of the motor (34).

10. An electric motor (34) having a rotor (10) according to any one of the preceding rotor claims and having a stator (36).

11. The motor (34) according to claim 10, wherein, The stator (36) includes a ring-shaped magnetic yoke having an inner side pointing inward in the radial direction, wherein a plurality of stator teeth (40) spaced apart from each other in the circumferential direction of the magnetic yoke are arranged on the inner side of the magnetic yoke, and wherein the outermost groove region (22b) is adapted to the distance between two spaced stator teeth (40) in terms of its circumferential spacing relative to each other.

12. A drive system for at least partially electrically driven motor vehicles, the drive system having an electric motor (34) according to claim 10 or 11 or having a rotor (10) according to any of the preceding rotor claims.

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