ROTOR FOR AN ELECTRIC MACHINE, AND ELECTRIC MACHINE

Abstract

A rotor (1) for an electric machine (16) which has at least two poles and an even number of N≥6 stacked rotor modules (2a-2f), wherein the rotor modules (2a-2f) for each pole have a magnet component (3a-3f; 3a-3h), and magnet components (3a-3f; 3a-3h) which embody the same pole form a corresponding magnet component arrangement (4a, 4b, 4f), wherein the first to Nth rotor module (2a-2f) are arranged in ascending sequence of their designation in the axial direction, wherein each magnet component (3a-3f; 3a-3h), belonging to one of the magnet component arrangements (4a), of the first to Nth rotor module (2a-2f) is arranged in each case at a stagger angle α.sub.1 . . . α.sub.N in the circumferential direction, wherein the stagger angles α.sub.i for 1≤i≤N/2 have a value α.sub.i=α.sub.0+k.Math.β where 0≤k≤[(N/2)−1], α.sub.0 is a fixed angular position in the circumferential direction, β is a fixed offset angle, and all the stagger angles α.sub.i are different from one another, wherein the stagger angles α.sub.m for [(N/2)+1]≤m≤N have a value α.sub.m=α.sub.N−m+1, characterized in that,
the stagger angle α.sub.i of at least two of the magnet components (3b) belonging to the magnet component arrangement (4a) is unequal to α.sub.0+(i−1).Math.β,

Claims

1. A rotor for an electric machine comprising: at least two poles; and an even number of N≥6 stacked rotor modules for each of the at least two poles, wherein the rotor modules for each pole have a magnet component, and magnet components which embody the same pole form a corresponding magnet component arrangement, wherein the first to Nth rotor module are arranged in ascending sequence of their designation in the axial direction, wherein each magnet component, belonging to one of the magnet component arrangements, of the first to Nth rotor module is arranged in each case at a stagger angle α.sub.1 . . . α.sub.N in the circumferential direction, wherein the stagger angles α.sub.i for 1≤i≤N/2 have a value α.sub.i=α.sub.0+k.Math.β where 0≤k≤[(N/2)−1], α.sub.0 is a fixed angular position in the circumferential direction, β is a fixed offset angle, and all the stagger angles α.sub.i are different from one another, wherein the stagger angles α.sub.m for [(N/2)+1]≤m≤N have a value α.sub.m=α.sub.N−m+1, the stagger angle α.sub.i of at least three of the magnet components belonging to the magnet component arrangement is unequal to α.sub.0+(i−1).Math.β.

2. The rotor as claimed in claim 1, wherein the offset angle β is positive or negative in the clockwise direction as viewed from an output side of the rotor.

3. The rotor as claimed in claim 1, wherein α.sub.1=α.sub.0.

4. The rotor as claimed in claim 3, wherein N=6.

5. The rotor as claimed in claim 4, wherein α.sub.2=α.sub.0+2.Math.β and α.sub.3=α.sub.0+β.

6. The rotor as claimed in claim 3, wherein N≥8.

7. The rotor as claimed in claim 6, wherein N=8.

8. The rotor as claimed in claim 7, wherein α.sub.2=α.sub.0+β and α.sub.3=α.sub.0+3.Math.β and α.sub.4=α.sub.0+2.Math.β.

9. The rotor as claimed in claim 7, wherein α.sub.2=α.sub.0+3.Math.β and α.sub.3=α.sub.0+2.Math.β and α.sub.4=α.sub.0+β.

10. The rotor as claimed in claim 7, wherein α.sub.2=α.sub.0+3.Math.β and α.sub.3=α.sub.0+β and α.sub.4=α.sub.0+2.Math.β.

11. The rotor as claimed in claim 6, wherein for each arrangement of [(N/2)−1] successive rotor modules (3a-3f; 3a-3h) of the first to (N/2)th rotor module (2a, 2b, 2c), at most [(N/2)−3] pair or pairs of directly adjacent magnet components (3a-3f; 3a-3h) of the magnet component arrangement are offset from one another by the single offset angle β.

12. The rotor as claimed in claim 1, wherein the axial width of each rotor module is at most 30 mm.

13. An electric machine, comprising: a stator; and a rotor as claimed in claim 1 inside the stator.

14. The electric machine as claimed in claim 13, wherein the stator has a plurality of stator teeth, which are each distanced from one another by a tooth angle, wherein the offset angle β is a positive integer multiple of the tooth angle.

Description

[0040] FIG. 1 is a side view of a first exemplary embodiment of a rotor 1.

[0041] The rotor in the present exemplary embodiment has, by way of example, P=6 poles and an even number of N=6 stacked rotor modules 2a to 2f. For each pole of the rotor 1, each rotor module 2a to 2f has a magnet component, wherein magnet components of the rotor modules 2a to 2f embodying the same pole form a magnet component arrangement 4a, 4b, 4f. For reasons of clarity, only one magnet component 3a of the first rotor module 2a, one magnet component 3b of the second rotor module 2b, one magnet component 3c of the third rotor module 2c, one magnet component 3d of the fourth rotor module 2d, one magnet component 3e of the fifth rotor module 2e, and one magnet component 3f of a sixth rotor module 2f, which together form a first magnet component arrangement 4a, have been provided with reference signs in FIG. 1. It can be seen that the first to sixth rotor module 2a to 2f are arranged in ascending sequence of their designation in the axial direction.

[0042] In addition, FIG. 1 shows a second magnet component arrangement 4b and a sixth magnet component arrangement 4f, wherein a third, a fourth and a fifth magnet component arrangement are disposed on a rear side of the rotor 1, which is hidden in FIG. 1. Here, merely by way of example, the magnet components 3a to 3f of the first magnet component arrangement 4a, the magnet components of the third magnet component arrangement, and the magnet components of the fifth magnet component arrangement each embody a north pole radially outwardly, whereas the magnet components of the second magnet component arrangement 4b, the magnet components of the fourth magnet component arrangement, and the magnet components of the sixth magnet component arrangement 4f each embody a south pole radially outwardly.

[0043] The magnet components 3a to 3f and the other magnet components are embodied as plate-like permanent magnets embedded in a laminated core 5 of the rotor 1 and are visible in FIG. 1. The rotor 1 also has a shaft 6.

[0044] FIG. 2 is a cutaway detail view of the rotor 1 as viewed from an output side 7 (see FIG. 1). Here, FIG. 2 shows a sector-like detail in the region of the first magnet component arrangement 4a, showing projections of the magnet components 3a to 3f.

[0045] The magnet components 3a to 3f belonging to the first magnet component arrangement 4a are each arranged at a stagger angle α.sub.1 . . . α.sub.N in the circumferential direction. FIG. 2 also shows three, in the circumferential direction, positive angles 8, 9, 10 in relation to a reference angle position 12. The angle 8 in this case designates the stagger angles α.sub.1, α.sub.6, at which the magnet components 3a and 3f are arranged, the angle 9 designates the stagger angles α.sub.3, α.sub.4, at which the magnet components 3c, 3d are arranged, and the angle 10 designates the stagger angles α.sub.2, α.sub.5, at which the magnet components 3b, 3e are arranged. Here, the stagger angles α.sub.3, α.sub.4 are greater than the stagger angles α.sub.1, α.sub.6 by an offset angle β, shown by an angle 11, and the stagger angles α.sub.2, α.sub.5 are greater than the aforesaid stagger angles α.sub.1, α.sub.6 by twice the offset angle β. Expressed as a formula, the following is true: α.sub.1=α.sub.0 and α.sub.2=α.sub.0+2.Math.β and β.sub.3=α.sub.0+β, wherein as describes an edge position in the circumferential direction of the magnet component, here the magnet component 3a, having the smallest angular value.

[0046] Consequently, the stagger angles α.sub.i for 1≤i≤3 have a value α.sub.i=α.sub.0+k.Math.β where 0≤k≤2. The stagger angles am for 4≤m≤6 have a value α.sub.m=α.sub.7−m, whereby they are distributed mirror-symmetrically in relation to a plane of symmetry 13 (see FIG. 1). In this respect, the first three or N/2 magnet components 3a, 3b, 3c on one side of the plane of symmetry 13 can also be designated as the first group, and the last three or N/2 magnet components 3d, 3e, 3f on the other side of the plane of symmetry 13 can also be designated as the second group.

[0047] Evidently, it is true for the magnet components 3a, 3b, 3c belonging to the first magnet component arrangement 4a that the stagger angles are α.sub.2=α.sub.0+2.Math.β≠α.sub.0+(2−1).Math.β and α.sub.3=α.sub.0+β≠α.sub.0+(3−1). An offset in the arrangement of the magnet components 3a to 3c is thus realized, and, due to the mirror-symmetrical arrangement, is also realized in the arrangement of the magnet components 3d to 3f.

[0048] Generally speaking, it is true for the first magnet component arrangement 4a that the stagger angles α.sub.i for 1≤i≤N/2 have a value α.sub.i=α.sub.0+k.Math.β where 0≤k≤[(N/2)−1] and all stagger angles α.sub.i are different from one another, that the stagger angles α.sub.m for [(N/2)+1]≤m≤N have a value α.sub.m=α.sub.N−m+1, and that the stagger angle α.sub.i of at least one of the magnet components 3b, 3c belonging to the magnet component arrangement is unequal to α.sub.0+(i−1).Math.β.

[0049] Again with reference to FIG. 1, the offset results in the clearly visible M-shaped arrangement of the magnet components 3a to 3f. For the rest of the magnet component arrangements 4b, 4f, the corresponding magnet components are arranged similarly thereto. The individual stagger angles of the magnet components of the other magnet component arrangements 4b, 4f are offset here by 60° or generally by 360°/P in the circumferential direction in relation to the preceding magnet component arrangement 4a, 4b.

[0050] FIG. 3 is a stagger schema of the rotor 1 with indicated axial forces during rotary operation of the rotor 1. A stagger schema illustrates here the position ratios of the magnet elements of a magnet component arrangement representative for the other magnet component arrangements in two-dimensional form. The offset angle β and axial distances of the magnet components are purely exemplary here. The multiples of the offset angle β of the individual magnet components are shown here in principle qualitatively by the stagger schema.

[0051] The axial forces effective during rotary operation are shown by arrows 14a, 14b, 15a, 15b. In this case, the arrows 14a, 14b relate to axial forces within the rotor modules 2a, 2b, 2c, which lie on the first side of the plane of symmetry 13, and the arrows 15a, 15b relate to axial forces within the rotor modules 2d, 2e, 2f, which lie on the other side of the plane of symmetry 13. The direction of the indicated axial forces is based here on an exemplary working point in rotary operation of the rotor 1. The direction of each indicated axial force can be reversed at other operating points, wherein, however, their arrangement relative to one another is maintained.

[0052] The mirror-symmetrical arrangement of the magnet components 3a to 3f firstly has the advantage that the axial forces cancel out one another over the entire length of the rotor 1. This is a significant advantage in view of NVH requirements. It can, however, also be seen that the axial forces represented by the arrows 14a, 14b on the one hand and the axial forces represented by the arrows 15a, 15b on the other hand compensate one another in part.

[0053] By way of comparison, FIG. 4 shows a stagger schema of a rotor according to the prior art with a V-shaped arrangement of magnet components. Visible here are axial forces shown by corresponding arrows 14′, 15′, specifically also of equal magnitude. However, there is no compensation within rotor modules on either side of the plane of symmetry 13′. In the rotor according to the prior art, an axial deformation, which may cause undesirable vibrations and noise and may transfer a standing wave to a stator, is much greater than in the rotor 1 according to the first exemplary embodiment.

[0054] In FIG. 4, double arrows 16′ additional signify that the condition according to which the stagger angle ai of at least two of the magnet components belonging to the magnet component arrangement is unequal to α.sub.0+(i−1).Math.β can be interpreted in this and the following exemplary embodiments as a swapping of the stagger angles of two magnet components.

[0055] FIGS. 5 to 7 each show a stagger schema of a further exemplary embodiment of a rotor with N=6.

[0056] For the stagger angles α.sub.1, α.sub.2, α.sub.3, the following is true in each case:

TABLE-US-00003 α.sub.1 = α.sub.0+ α.sub.2 = α.sub.0+ α.sub.3 = α.sub.0+ FIG. 5 β 0 2 .Math. β FIG. 6 β 2 .Math. β 0 FIG. 7 2 .Math. β 0 β

[0057] Due to the mirror symmetry, the further stagger angles can α.sub.4, α.sub.5, α.sub.6 of course be determined therefrom similarly. Consequently, the exemplary embodiments according to FIG. 5 and FIG. 7 can be interpreted as a W-shaped arrangement and the exemplary embodiment according to FIG. 6 can be interpreted as a M-shaped arrangement.

[0058] FIGS. 8 to 29 each show a stagger schema of a further exemplary embodiment of a rotor with N=8, wherein in FIG. 8 to FIG. 10 axial forces corresponding to FIG. 3 are additionally indicated, In these exemplary embodiments, a seventh and eighth rotor module are of course provided. Furthermore, the first group of magnet components 3a to 3d has stagger angles α.sub.1, α.sub.2, α.sub.3, α.sub.4 and the second group of magnet components 3e to 3h has stagger angles α.sub.5, α.sub.6, α.sub.7, α.sub.8. The other statements provided for the first exemplary embodiment apply for the exemplary embodiments with N=8 accordingly, provided nothing to the contrary is described hereinafter.

[0059] In the exemplary embodiment according to FIG. 8, it is true that α.sub.1=α.sub.0, α.sub.2=α.sub.0+β, α.sub.3=α.sub.0+3.Math.β and α.sub.4=α.sub.0+2.Math.β. As can be seen, the axial forces represented by the arrows 14a, 14b on the one hand and the axial forces represented by the arrows 15a, 15b advantageously cancel out one another on each side of the plane of symmetry 13. Again, a M-shaped arrangement is provided.

[0060] In the exemplary embodiment according to FIG. 9, it is true that α.sub.1=α.sub.0, α.sub.2=α.sub.0+3.Math.β and α.sub.3=α.sub.0+2β and α.sub.4=α.sub.0+β. As can be seen, the axial forces represented by the arrows 14a, 14b on the one hand and the axial forces represented by the arrows 15a, 15b advantageously cancel out one another in part on each side of the plane of symmetry 13. Again, a M-shaped arrangement is provided.

[0061] In the exemplary embodiment according to FIG. 10, it is true that α.sub.1=α.sub.0, α.sub.2=α.sub.0+3.Math.β, α.sub.3=α.sub.0+β and α.sub.4=α.sub.0+2.Math.β. As can be seen, the axial forces represented by the arrows 14a, 14b, 14c on the one hand and the axial forces represented by the arrows 15a, 15b, 15c advantageously cancel out one another in part on each side of the plane of symmetry 13. This arrangement can be interpreted as being zigzagged.

[0062] In the exemplary embodiments according to FIG. 11 to FIG. 29, the indication of the reference signs 3a to 3f and 13 has been omitted for reasons of clarity. Here, more specifically, the following is true for the stagger angles α.sub.1, α.sub.2, α.sub.3, α.sub.4:

TABLE-US-00004 α.sub.1 = α.sub.0+ α.sub.2 = α.sub.0+ α.sub.3 = α.sub.0+ α.sub.4 = α.sub.0+ FIG. 11 0 2 .Math. β β 3 .Math. β FIG. 12 0 2 .Math. β 3 .Math. β β FIG. 13 β 0 3 .Math. β 2 .Math. β FIG. 14 β 0 2 .Math. β 3 .Math. β FIG. 15 β 3 .Math. β 0 2 .Math. β FIG. 16 β 3 .Math. β 2 .Math. β 0 FIG. 17 β 2 .Math. β 0 3 .Math. β FIG. 18 β 2 .Math. β 3 .Math. β 0 FIG. 19 2 .Math. β 0 β 3 .Math. β FIG. 20 2 .Math. β 0 3 .Math. β β FIG. 21 2 .Math. β β 0 3 .Math. β FIG. 22 2 .Math. β β 3 .Math. β 0 FIG. 23 2 .Math. β 3 .Math. β 0 β FIG. 24 2 .Math. β 3 .Math. β β 0 FIG. 25 3 .Math. β 0 β 2 .Math. β FIG. 26 3 .Math. β 0 2 .Math. β β FIG. 27 3 .Math. β β 0 2 .Math. β FIG. 28 3 .Math. β β 2 .Math. β 0 FIG. 29 3 .Math. β 2 .Math. β 0 β

[0063] According to further exemplary embodiments of a rotor which, for the rest, correspond to one of the previously described exemplary embodiments, the magnet components are embodied as surface-mounted permanent magnets.

[0064] FIG. 30 is a basic diagram of an exemplary embodiment of an electric machine 16.

[0065] The electric machine 16 comprises a stator 17 with stator grooves or stator teeth 18. Typically, the stator grooves or stator teeth are straight in the axial direction. A rotor 1 according to one of the previously described exemplary embodiments is arranged rotatably inside the stator 17. The stator teeth 18 are preferably each distanced from one another by a tooth angle, wherein the offset angle β is a positive integer multiple of the tooth angle,

[0066] The electric machine 16 is designed to drive a vehicle, for example an electric vehicle or a hybrid vehicle.