Rotors for electric motors

Abstract

The invention relates to a rotor (R) for an electric machine, wherein the rotor comprises a plurality of annularly shaped laminated core segments (BS) which are arranged one behind the other in the longitudinal direction of the rotor (R), and each laminated core segment (BS) comprises at least one recess (T) with a pole piece (PK) arranged therein, wherein the pole pieces (PK) arranged one behind the other in the longitudinal direction of the rotor (R) form a pole pack (PBG), and the pole pack (PBG) has a W-shaped course relative to its longitudinal direction.

Description

Technical Field

[0001] The invention relates to a rotor for an electric machine, wherein the rotor comprises at least one pole assembly consisting of a plurality of pole parts, wherein the pole parts have a W-shaped inclination relative to the longitudinal direction of the rotor. The invention also relates to an electric machine having a rotor according to the invention and a motor vehicle having an electric machine according to the invention. Background Art

[0002] Rotors for electric machines are known in principle. Known rotors usually have a plurality of laminated core sections arranged one behind the other in the longitudinal direction of the rotor. Receptacles and / or recesses for accommodating pole parts are formed in the laminated core sections. It is also known to arrange the laminated core sections relative to one another in such a way that they are arranged offset from one another in the circumferential direction, so that the pole parts of the pole assembly have, for example, a linear inclination. However, a linear inclination is not suitable or optimal for every electric machine and may have a negative impact on the vibration and noise characteristics of the electric machine. Summary of the invention

[0003] The object of the present invention is to specify a rotor for an electric machine with which vibrations and / or noise generation of the electric machine can be reduced.

[0004] This object is achieved by a rotor for an electric machine, an electric machine, and a motor vehicle according to the invention. Preferred embodiments of the invention are described in the preferred embodiments, the description, and the drawings, wherein each feature may represent an aspect of the invention both individually and in combination.

[0005] According to the present invention, a rotor for an electric machine is provided, which has a plurality of annularly constructed laminated core sections, which are arranged one after another in the longitudinal direction of the rotor, wherein each laminated core section has at least one recess together with a pole piece arranged therein, the pole piece comprising a side surface parallel to the longitudinal direction of the rotor, wherein the pole pieces arranged one after another in the longitudinal direction of the rotor form a pole assembly, and the pole assembly has a first subgroup, a second subgroup and a third subgroup, wherein the third subgroup is arranged between the first subgroup and the second subgroup, and the laminated core sections are arranged offset from each other in the circumferential direction, so that the first subgroup and the second subgroup respectively comprise a plurality of pole pieces, and the third subgroup comprises pole pieces, and the pole pieces of the first subgroup are mutually offset in the first direction. The pole parts of the second subgroup are arranged offset to each other in a second direction opposite to the first direction, wherein the side surfaces of the pole parts of the second subgroup have a second offset to each other and the sum of the second offsets of the pole parts of the second subgroup forms a second maximum offset, and the side surfaces of the pole parts of the third subgroup have a third offset relative to the corresponding side surfaces of the pole parts of the first subgroup, which have a maximum distance relative to the pole parts of the third subgroup in the axial direction of the rotor, wherein the absolute value of the third offset is smaller than the absolute value of the first maximum offset and smaller than the absolute value of the second maximum offset.

[0006] In other words, one aspect of the present invention is to provide a rotor for an electric machine, which has a plurality of annularly configured laminated core sections, which are arranged one after another in the axial direction of the rotor. The corresponding laminated core sections usually have a plurality of laminated disks, which are identical for the laminated core sections and are combined into the laminated core sections.

[0007] Each laminated core section has at least one recess with a pole part arranged therein. Typically, each laminated core has a plurality of recesses spaced apart from one another in the circumferential direction, wherein a pole part is arranged in each recess. The pole part can also be referred to as a magnet or in particular as a permanent magnet.

[0008] The recess cross section and / or the recess arrangement can preferably be arranged and / or designed to be rectilinear and / or V-shaped.

[0009] The pole parts arranged in the lamination stack section have side surfaces parallel to the longitudinal direction of the rotor. The side surfaces are preferably oriented and / or formed along the peripheral direction of the rotor or along the peripheral direction of the lamination stack section of the annular structure. The pole parts arranged in sequence along the longitudinal direction of the rotor constitute a pole assembly. The pole assembly includes a first subgroup, a second subgroup and a third subgroup. It is provided that the third subgroup is arranged between the first subgroup and the second subgroup. Not only the first subgroup but also the second subgroup have multiple pole parts respectively. In other words, the first subgroup can, for example, have 2, 3, 4, 5, 6, 7 or more pole parts. It can also be provided that the second subgroup has 2, 3, 4, 5, 6, 7 or more pole parts. The third subgroup includes only one pole part.

[0010] The laminated core segments are arranged offset relative to one another in the circumferential direction, wherein the pole parts of the first subgroup are arranged offset relative to one another in the first direction, so that the side faces of the pole parts of the first subgroup have a first offset relative to one another. In other words, the pole parts of the first subgroup are arranged offset relative to one another in the circumferential direction of the rotor, wherein the first offset is formed between the respective side faces of the pole parts. The sum of the first offsets of the pole parts of the first subgroup forms a first maximum offset:

[0011]

[0012] The pole parts of the second subgroup are arranged offset to one another in a second direction opposite to the first direction, so that the side faces of the pole parts of the second subgroup have a second offset to one another. The pole parts of the second subgroup are therefore also arranged offset to one another in the peripheral direction, wherein the offset direction of the pole parts of the first subgroup is different from the offset direction of the pole parts of the second subgroup. In other words, the first direction is designed opposite to the second direction. The sum of the displacements of the pole parts of the second subgroup forms a second maximum displacement:

[0013]

[0014] The side faces of the pole pieces of the third subset have a third offset relative to the corresponding side faces of the pole pieces of the first and second subsets, which have a maximum distance in the axial direction of the rotor relative to the first pole piece of the third subset, wherein the absolute value of the third offset is smaller on the one hand than the absolute value of the first maximum offset and smaller on the other hand than the absolute value of the second maximum offset: |V max1 |>|V3|<|V max2 |.

[0015] In this way, the pole assembly has a W-shaped course in the longitudinal direction of the pole assembly.

[0016] The rotor is usually rotatably supported and is arranged spaced apart from the stator surrounding the rotor by an air gap. In the air gap, there is a time- and position-dependent force distribution in the radial, tangential and axial directions. This force distribution is significantly affected by the rotor structure and can excite the stator and cause vibration and / or noise formation. The lamination stack section of the rotor is tilted so that the pole parts of the pole assembly have a W-shaped direction, which can have a positive effect on the noise and vibration severity of the motor and reduce the vibration and / or noise formation of the stator. In particular, the force acting in the axial direction and / or its influence on the stator can be reduced and / or eliminated. In addition, the force distribution of the radial and / or tangential forces can be adjusted so that the self-mode (Eigenmode) of the stator is not too strongly excited, until it is not excited.

[0017] In an advantageous embodiment of the invention, it is provided that the absolute value of the first maximum deflection is equal to the absolute value of the second maximum deflection. In other words, the sum of the first deflections of the pole parts of the first subgroup is equal to the sum of the second deflections of the pole parts of the second subgroup:

[0018] |V max1 |=|V max2 |.

[0019] Alternatively, an advantageous development of the invention is that the second maximum deflection differs from the first maximum deflection. In other words, the sum of the deflections of the pole parts of the first subgroup can be greater or less than the sum of the deflections of the pole parts of the second subgroup. In this way, the pole assembly can preferably have a W-shaped course in the longitudinal direction of the pole assembly, which is non-uniform or asymmetrical:

[0020] |V max1 |<|V max2 |or|V max1 |>|V max2 |.

[0021] Advantageously, it is provided that the first offsets between the side surfaces of the pole parts of the first subgroup and / or the second offsets between the side surfaces of the pole parts of the second subgroup are always of the same size. In other words, the first subgroup can, for example, comprise three pole parts, wherein the corresponding first offsets of the side surfaces of consecutive pole parts are always of the same size. It can also be provided that the corresponding second offsets of the side surfaces of the pole parts of the second subgroup that are spaced apart from each other are always of the same size. However, it is not mandatory that the first offsets must be of the same size if the second offsets are of the same size. For example, the first offsets can also be different from each other, while the second offsets are of the same size.

[0022] Alternatively and / or in addition, it can be provided that the first offsets between the side surfaces of the pole parts of the first subgroup and / or the second offsets between the side surfaces of the pole parts of the second subgroup differ from one another. It is therefore conceivable that the first subgroup preferably has three laminated stack sections with corresponding pole parts, wherein the first offsets between the side surfaces of consecutive pole parts differ from one another. The same applies to the second offsets. However, it is also conceivable that the first offsets of the pole parts of the first subgroup are of equal size, while the second offsets of the pole parts of the second subgroup differ from one another.

[0023] In principle, a preferred embodiment of the invention can provide that within the pole assembly the number of pole elements of the first subgroup is equal to the number of pole elements of the second subgroup.

[0024] Alternatively, it can be provided that within the pole assembly, the number of pole parts of the first subgroup differs from the number of pole parts of the second subgroup. In other words, it can be provided that the first subgroup preferably has three laminated core sections with corresponding pole parts, wherein the second subgroup preferably comprises four laminated core sections with corresponding pole parts. In this way, the pole assembly can preferably have a W-shaped course in the longitudinal direction of the pole assembly, which is uneven and / or asymmetrical.

[0025] In an advantageous embodiment of the invention, it is provided that the pole parts of the first subgroup and the pole parts of the second subgroup have an offset position, wherein the offset position of the first subgroup is identical to the offset position of the second subgroup. The offset position defines the position of the recess in the laminated stack section in which the pole parts are arranged. In other words, the pole parts of the first subgroup are designed in a mirror-image manner relative to the pole parts of the second subgroup with respect to an axis perpendicular to the longitudinal direction of the pole assembly. In this way, preferably a uniform or symmetrical W-shaped course of the pole parts relative to the longitudinal direction of the pole assembly can be achieved.

[0026] An advantageous development of the invention is that the pole parts of the third subgroup have an offset position, wherein the offset position of the pole parts of the third subgroup corresponds to the offset position of the pole parts of the first subgroup and / or the offset position of the pole parts of the second subgroup. It can therefore be provided that the side faces of the pole parts of the third subgroup are flush with the side faces of the pole parts of the first subgroup on the one hand and with the side faces of the pole parts of the second subgroup on the other hand. In this way, the number of offset positions of the pole parts can be reduced.

[0027] In an advantageous embodiment of the invention, it is provided that the rotor has a plurality of pole assemblies which are spaced apart from one another in the circumferential direction.

[0028] It is conceivable that the pole parts have different sizes and / or shapes. An advantageous embodiment of the invention provides that all pole parts have the same size.

[0029] The invention relates to an electric machine having a rotor according to the invention and to a motor vehicle having an electric machine according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further features of the invention are obtained from the preferred embodiments and the following examples. The examples should not be understood as limiting, but rather as exemplary. They should enable a person skilled in the art to implement the invention. The applicant reserves one or more of the features disclosed in the examples as the subject of an embodiment, or accommodates these features in an existing embodiment. The examples are described in detail with reference to the accompanying drawings. In them:

[0031] Figure 1a A three-dimensional view of a rotor of an electric machine with a pole assembly is shown;

[0032] Figure 1b A top view of a lamination stack of a rotor is shown;

[0033] Figures 2 to 8 Different examples of arrangements of pole parts within a pole assembly are shown. DETAILED DESCRIPTION

[0034] Figure 1a 1 shows a three-dimensional view of a rotor R for an electric machine. The rotor R has a plurality of annularly shaped laminated core sections BS, which are arranged one behind the other in the longitudinal direction of the rotor R. Each laminated core section BS has at least one recess T with a pole part PK arranged therein. The pole part PK can also be referred to as a magnet, in particular a permanent magnet.

[0035] In the present embodiment, each laminated core section BS has a plurality of recesses T arranged spaced apart from one another in the circumferential direction, wherein the recesses T have a rectangular opening having a straight course in the tangential direction of the laminated core section BS. In principle, the recesses T can also be constructed and / or arranged in a V-shape, such as in Figure 1a As shown in the example.

[0036] The pole parts PK have an outer side AS in the radial direction of the rotor R and a side surface SF parallel to the longitudinal direction of the rotor R. The pole parts PK arranged one behind the other in the longitudinal direction of the rotor R form a pole assembly PBG.

[0037] The pole assembly PBG comprises a first subgroup U1 , a second subgroup U2 and a third subgroup U3 , wherein the third subgroup U3 is arranged between the first subgroup U1 and the second subgroup U2 .

[0038] Both the first subgroup U1 and the second subgroup U2 each have a plurality of pole parts PK. The third subgroup U3 has only one pole part PK. The pole parts PK of the pole assembly PBG are arranged relative to one another in the longitudinal direction of the pole assembly PBG or in the longitudinal direction of the rotor R such that they have and / or form a W-shaped course in the longitudinal direction of the pole assembly PBG.

[0039] Figures 2 to 8 Different embodiments of the arrangement of the pole parts PK within the pole assembly PBG are shown for a different number of laminated core segments BS. Figures 2 to 8 The illustration is limited to the pole part PK. Figures 2 to 8 The rotor R or the laminated core section BS are not shown.

[0040] Figure 2 A pole assembly PBG according to a first preferred embodiment is shown in FIG. The rotor R of this embodiment includes five laminated sheet segments BS arranged in sequence in the longitudinal direction of the rotor R. Therefore, the pole assembly PBG includes five pole parts PK arranged in sequence in the longitudinal direction of the pole assembly PBG. The pole assembly PBG has a first subgroup U1, a second subgroup U2, and a third subgroup U3 arranged between the first subgroup U1 and the second subgroup U2. The first subgroup U1 and the second subgroup U2 each have two pole parts PK. The third subgroup U3 includes a pole part PK. The pole parts PK of the first subgroup U1 are arranged offset from each other in a first direction R1, so that the side faces SF of the pole parts PK of the first subgroup have a first offset V1 from each other. The sum of the first offsets V1 of the pole parts PK of the first subgroup U1 forms a first maximum offset V max1 In the case of only two pole parts PK of the first subgroup, the first offset V1 corresponds to the first maximum offset V max1 .

[0041] The pole parts PK of the second subset U2 are arranged offset to one another in a second direction R2 opposite to the first direction R1, so that the side faces SF of the pole parts PK of the second subset U2 have a second offset V2 to one another, and the sum of the second offsets V2 of the pole parts PK of the second subset U2 forms a second maximum offset V max2 The side faces SF of the pole pieces PK of the third subset U3 have a third offset V3 with respect to the corresponding side faces SF of the pole pieces PK of the first subset U1 and the second subset U2, which have the maximum distance relative to the pole pieces PK of the third subset U3 in the axial direction of the rotor R. The absolute value of the third offset V3 is smaller than the first maximum offset V max1 The absolute value of the second maximum offset V max2 The absolute value of .

[0042] In addition, it can be seen that in the first embodiment, the first maximum offset V max1 The absolute value is equal to the second maximum offset Vmax2 In addition, the pole parts PK of the first subgroup U1 and the pole parts PK of the second subgroup U2 have an offset position, wherein the offset position of the pole parts PK of the first subgroup U1 is identical to the offset position of the pole parts PK of the second subgroup U2. In other words, the pole parts PK of the first subgroup U1 are constructed and / or arranged in a mirror-image manner relative to the pole parts of the second subgroup U2 with respect to an axis perpendicular to the longitudinal direction of the pole assembly PBG. In this way, the pole assembly PBG has a W-shaped course in the longitudinal direction that is constructed in the same shape.

[0043] Figure 3 FIG. 4 shows a pole assembly PBG according to a second embodiment. Figure 2 Unlike the pole assembly PBG shown, the second subgroup U2 has two pole parts PK, wherein the second offset V2 differs from the first offset V1 of the pole parts PK of the first subgroup U1. In addition, the second maximum offset V max2 The absolute value is less than the first maximum offset V max1 The third offset V3 is smaller than the second maximum offset V max2 The pole assembly PBG therefore has a non-uniform W-shaped course in its longitudinal direction.

[0044] Figures 4 to 7 A pole assembly PBG is shown in each case with seven pole parts PK arranged one behind the other. Accordingly, the rotor R has a total of seven laminated core segments BS arranged one behind the other.

[0045] exist Figure 4 In the embodiment, the first subgroup U1 and the second subgroup U2 each have three pole parts PK. The respective pole parts PK of the first subgroup U1 each have a uniform first offset V1. Similarly, the pole parts PK of the third subgroup U3 each have a uniform second offset V2. In addition, the first maximum offset V max1 The absolute value is equal to the second maximum offset V max2 In addition, the pole parts PK of the first subset U1 and the pole parts PK of the second subset U2 have an offset position, wherein the offset position of the pole parts PK of the first subset U1 is identical to the offset position of the pole parts PK of the second subset U2. In other words, the pole parts PK of the first subset U1 are arranged in a mirror-image manner relative to the pole parts PK of the second subset U2 about an axis perpendicular to the pole assembly PBG.

[0046] Furthermore, the side faces SF of the pole pieces PK of the third subset U3 have a third offset V3 relative to the corresponding side faces SF of the pole pieces PK of the first subset U1 and the second subset U2 (which have a maximum distance relative to the pole pieces PK of the third subset U3 in the axial direction of the rotor R), wherein the absolute value of the third offset V3 is smaller than the first maximum offset V max1 The absolute value of the second maximum offset V max2The absolute value of .

[0047] Furthermore, it can be seen that the pole parts PK of the third subset U3 have an offset position which corresponds to the offset position of the pole parts PK of the first subset U1 and of the second subset U2 .

[0048] In particular, it is provided that the absolute value of the first offset V1 , the absolute value of the second offset V2 and the absolute value of the third offset V3 are equally large. For example, the absolute value of the first offset V1 , the second offset V2 and the third offset V3 can each be 2.887°.

[0049] In this way, the number of offset positions can be reduced. In other words, costs can be reduced because the number of different laminate cross sections of the laminate stack section BS can be reduced.

[0050] Figure 5 FIG. 4 shows a pole assembly PBG according to a fourth embodiment. Figure 4 Unlike the embodiment shown, the offset position of the pole parts PK of the first subgroup U1 does not correspond to the offset position of the pole parts PK of the second subgroup U2. Therefore, the offset position of the pole parts PK of the first subgroup U1 is different from the offset position of the pole parts PK of the second subgroup U2. In the present embodiment, the offset position of the pole parts PK of the third subgroup U3 corresponds to the offset position of the pole parts PK of the first subgroup U1. Therefore, the pole assembly PBG has an uneven W-shaped course in the longitudinal direction of the pole assembly PBG.

[0051] Figure 6 FIG. 4 shows a pole assembly PBG according to a fifth embodiment. Figure 4 Unlike the exemplary embodiment shown, the first offsets V1 between the side faces SF of the pole parts PK of the first subgroup U1 are designed to be unequal in size. The second offsets V2 between the side faces SF of the pole parts PK of the second subgroup U2 are designed to be equally large. It can also be seen that the first maximum offset V max1 The absolute value is less than the second maximum offset V max2 The absolute value of the third offset V3 is smaller than the absolute value of the first maximum offset V max1 .

[0052] Figure 7 , a pole assembly PBG according to a sixth embodiment is shown. The first offset V1 of the pole parts PK of the first subgroup U1 is of equal magnitude. Likewise, the second offset V2 of the pole parts PK of the second subgroup within the subgroup is of equal magnitude. However, the absolute value of the first offset V1 of the pole parts PK of the first subgroup U1 is different from the absolute value of the second offset V2 of the second pole parts PK of the second subgroup U2. In this embodiment, the absolute value of the first offset V1 is greater than the absolute value of the second offset V2. In addition, the first maximum offset V max1 The absolute value is greater than the second maximum offset Vmax2 The offset position of the pole parts PK of the third subgroup U3 is different from the offset position of the pole parts PK of the first subgroup U1 and the offset position of the pole parts PK of the second subgroup U2. The pole assembly PBG has an uneven W-shaped course in its longitudinal course.

[0053] Figure 8 , a pole assembly PBG having eight pole parts PK arranged in sequence is shown. In other words, the rotor R has a total of eight laminated stack segments BS arranged in sequence. The first subset U1 includes three pole parts PK, and the second subset U2 includes four pole parts PK. The first offset V1 between the side faces SF of the pole parts PK of the first subset U1 is of equal size. Likewise, the second offset V2 between the side faces SF of the pole parts PK of the second subset U2 is of equal size. However, the absolute value of the first offset V1 is greater than the absolute value of the second offset V2. Since the number of pole parts PK of the first subset U1 is less than the number of pole parts PK of the second subset U2, the first maximum offset V1 of the first subset U1 is greater than the absolute value of the second offset V2. max1 The absolute value of which is smaller than the second maximum offset V max2 The absolute value of the third offset V3 is not only smaller than the absolute value of the first maximum offset V max1 The absolute value of the second maximum offset V max2 Due to the even number of laminated stack segments BS or pole parts PK and the fact that the third subgroup U3 has only one pole part PK, the pole assembly PBG has a W-shaped, uneven course along its length.

Claims

1. A rotor (R) for an electric motor having: A plurality of annularly shaped laminated core segments (BS) are arranged one behind the other in the longitudinal direction of a rotor (R), wherein each laminated core segment (BS) has at least one recess (T) with a pole piece (PK) arranged therein, the pole piece comprising a side surface (SF) parallel to the longitudinal direction of the rotor (R), wherein The pole parts (PK) arranged one after the other in the longitudinal direction of the rotor (R) form a pole assembly (PBG), and the pole assembly (PBG) has a first subgroup (U1), a second subgroup (U2) and a third subgroup (U3), wherein the third subgroup (U3) is arranged between the first subgroup (U1) and the second subgroup (U2), The first subgroup (U1) and the second subgroup (U2) each comprise a plurality of pole parts (PK), and the third subgroup (U3) comprises only one pole part (PK), the laminated core sections being arranged offset relative to one another in a circumferential direction, so that adjacent pole parts (PK) of the first subgroup (U1) are arranged offset relative to one another in a first direction (R1), wherein side faces (SF) of adjacent pole parts (PK) of the first subgroup (U1) have a first offset (V1) relative to one another, and the sum of the first offsets (V1) of the pole parts (PK) of the first subgroup (U1) forms a first maximum offset (V1). max1 ), Adjacent pole components (PK) of the second subset (U2) are arranged offset to one another in a second direction (R2) opposite to the first direction (R1), wherein side surfaces (SF) of adjacent pole components (PK) of the second subset (U2) have a second offset (V2) to one another, and the sum of the second offsets (V2) of the pole components (PK) of the second subset (U2) forms a second maximum offset (V2). max2 ),and The side face (SF) of the pole pieces (PK) of the third subset (U3) has a third offset (V3) relative to the corresponding side face (SF) of the pole pieces (PK) of the first subset (U1) and the second subset (U2), the side face having a maximum distance relative to the pole pieces (PK) of the third subset (U3) in the axial direction of the rotor (R), and the absolute value of the third offset (V3) is smaller than the first maximum offset (V max1 ) and is smaller than the second maximum offset (V max2 ), in, The pole parts (PK) of the first subgroup (U1), the second subgroup (U2) and the third subgroup (U3) are arranged such that the pole assembly (PBG) has a W-shaped course in the longitudinal direction.

2. The rotor (R) according to claim 1, characterized in that The first maximum offset (V max1 ) is equal to the absolute value of the second maximum offset (V max2 )’s absolute value.

3. The rotor (R) according to claim 1, characterized in that The second maximum deviation (V max2 ) and the absolute value of the first maximum deviation (V max1 ) have different absolute values.

4. A rotor (R) according to any one of claims 1 to 3, characterized in that A first offset (V1) between the side surfaces (SF) of the pole parts (PK) of the first subgroup (U1) and / or a second offset (V2) between the side surfaces (SF) of the pole parts (PK) of the second subgroup (U2) are always of the same magnitude.

5. A rotor (R) according to any one of claims 1 to 3, characterized in that A first offset (V1) between the side surfaces (SF) of the pole parts (PK) of the first subset (U1) and / or a second offset (V2) between the side surfaces (SF) of the pole parts (PK) of the second subset (U2) differ from each other.

6. A rotor (R) according to any one of claims 1 to 3, characterised in that Within the pole assembly (PBG), the number of pole components (PK) of the first subgroup (U1) is equal to the number of pole components (PK) of the second subgroup (U2).

7. A rotor (R) according to any one of claims 1 to 3, characterised in that Within the pole assembly (PBG), the number of pole components (PK) of a first subset (U1) is different from the number of pole components (PK) of a second subset (U2).

8. The rotor (R) according to claim 1 or 2, characterized in that The pole parts (PK) of the first subset (U1) and the pole parts (PK) of the second subset (U2) have an offset position, wherein the offset position of the pole parts (PK) of the first subset (U1) is the same as the offset position of the pole parts (PK) of the second subset (U2).

9. The rotor (R) according to claim 8, characterized in that The pole pieces (PK) of the third subset (U3) have an offset position corresponding to the offset positions of the pole pieces (PK) of the first subset (U1) and the second subset (U2).

10. A rotor (R) according to any one of claims 1 to 3, characterised in that The rotor (R) has a plurality of pole pieces (PBG) spaced apart from each other in a circumferential direction.

11. An electric machine having a rotor (R) according to any one of claims 1 to 10.

12. A motor vehicle having an electric machine according to claim 11.

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