ROTOR FOR AN ELECTRICAL MACHINE, AND ELECTRICAL MACHINE

Abstract

A rotor (20) for an electrical machine (21) is provided, the rotor (20) comprising: a main rotor (22) which is rotatable around a longitudinal axis (z), and at least one auxiliary rotor (23) representing an axial flux rotor, wherein the auxiliary rotor (23) is also rotatable around the longitudinal axis (z) and is arranged along the longitudinal axis (z) so as to be adjacent to the main rotor (22), the auxiliary rotor (23) comprises at least one permanent magnet (24), and the permanent magnet (24) has at least in parts the shape of a ring. Further, an electrical machine (21) is provided.

Claims

1. A rotor for an electrical machine, the rotor comprising: a main rotor which is rotatable around a longitudinal axis, and at least one auxiliary rotor, which is an axial flux rotor, wherein the auxiliary rotor is also rotatable around the longitudinal axis and is arranged along the longitudinal axis so as to be adjacent to the main rotor, the auxiliary rotor comprises at least one permanent magnet, and the permanent magnet has the shape of a ring at least in parts.

2. The rotor according to claim 1, in which the main rotor is formed as a claw pole type rotor having an excitation coil.

3. The rotor according to claim 1, which comprises a further auxiliary rotor, with the main rotor being arranged along the longitudinal axis between the auxiliary rotor and the further auxiliary rotor.

4. The rotor according to claim 1, in which the magnetic axis of the permanent magnet extends parallel to the longitudinal axis.

5. The rotor according to claim 1, in which the auxiliary rotor has a rotor core which has the shape of a ring at least in parts.

6. The rotor according to the preceding claim, in which the rotor core has teeth which extend toward the main rotor and are arranged to be spaced from one another.

7. The rotor according to any of claims 5 or 6, in which the permanent magnet is arranged at least in parts along the longitudinal axis between the rotor core and the main rotor.

8. The rotor according to claim 1, in which the permanent magnet has recesses along its outer circumference which extend in the direction of the longitudinal axis partially through the permanent magnet.

9. The rotor according to the preceding claim, in which the recesses are equal in size and have equal distances to each other.

10. The rotor according to claim 1, in which further permanent magnets are connected to the permanent magnet, the further permanent magnets being arranged along the outer circumference of the permanent magnet so as to be spaced from each other.

11. The rotor according to claim 1, in which the magnetic axes of the further permanent magnets extend parallel to the magnetic axis of the permanent magnet.

12. The rotor according to claim 1, in which the number of the further permanent magnets is equal to the number of the pole pairs of the main rotor.

13. An electrical machine comprising a rotor according to any of the claims 1 to 12 and a stator.

14. The electrical machine according to claim 13, in which the stator has a winding with winding heads, with the main rotor extending as far as the area of the stator between the winding heads along the longitudinal axis.

Description

[0028] In the following, the rotor described here and the electrical machine are explained in more detail in conjunction with exemplary embodiments and the corresponding Figures.

[0029] FIGS. 1A, 1B, 1C and 1D depict an exemplary embodiment of the rotor.

[0030] FIGS. 2A, 2B, 2C and 2D depict a further exemplary embodiment of the rotor.

[0031] FIGS. 3A, 3B, 3C and 3D depict a further exemplary embodiment of the rotor.

[0032] FIGS. 4A and 4B show an exemplary embodiment of the electrical machine.

[0033] FIG. 5 shows a schematic cross-section through a part of an exemplary embodiment of the electrical machine.

[0034] FIGS. 6A and 6B show an exemplary embodiment of the stator.

[0035] FIG. 7 shows a detail of an exemplary embodiment of the electrical machine.

[0036] FIG. 1A shows an exemplary embodiment of a rotor 20 for an electrical machine 21. Individual components of the rotor 20 are shown separately for better understanding. In the assembled state, the individual components form the exemplary embodiment of the rotor 20.

[0037] The rotor 20 has a main rotor 22 which is rotatable around a longitudinal axis z. The longitudinal axis z extends through the rotor 20. The main rotor 22 is a claw pole type rotor. The main rotor 22 has several claws 32 which are distributed along the circumference of the main rotor 22. Furthermore, the main rotor 22 has an excitation coil 39. The claws 32 are arranged around the excitation coil 39. The main rotor 22 has approximately the shape of a cylinder. The claws 32 each have a base area in the shape of a trapezoid. The base area extends along the circumference of the main rotor 22. The main rotor 22 has two end faces 33, which form the base areas of the cylinder. The claws 32 are arranged in such a way that one half of the claws 32 has the longer base of the base area of the trapezoid pointing toward one of the end faces 33 and the other half of the claws 32 has the shorter base of the base area pointing toward this end face 33. Thus, the claws 32 are alternately distributed along the circumference of the main rotor 22.

[0038] Moreover, the rotor 20 has an auxiliary rotor 23 and a further auxiliary rotor 25. The auxiliary rotor 23 is an axial flow rotor. In addition, the auxiliary rotor 23 can also be rotated about the longitudinal axis Z and is arranged along the longitudinal axis Z adjacent to the main rotor 22. The auxiliary rotor 23 comprises a permanent magnet 24 and a further permanent magnets 29. The permanent magnet 24 has the shape of a ring. The ring is arranged around the longitudinal axis z. Thus, the center of the ring lies on the longitudinal axis z.

[0039] The further permanent magnets 29 are connected to the permanent magnet 24. In this arrangement, the further permanent magnets 29 are arranged along the outer circumference of the permanent magnet 24 so as to be spaced from each other. The permanent magnet 24 with the further permanent magnets 29 thus form a ring which has recesses 28 along its outer circumference. The further permanent magnets 29 each have the same size and are arranged at equal distances from each other along the circumference of the permanent magnet 24. In addition, the magnetic axes of the further permanent magnets 29 extend parallel to the magnetic axis of the permanent magnet 24. The magnetic axis of the permanent magnet 24 is parallel to the longitudinal axis z. The permanent magnet 24 has a smaller extension along the longitudinal axis z than along a radial direction r, which is perpendicular to the longitudinal axis z. The further permanent magnets 29 also have a smaller extension along the longitudinal axis z than along a radial direction r.

[0040] The auxiliary rotor 23 also comprises a rotor core 26, which has the shape of a ring at least in parts. The rotor core 26 may contain iron and serve as a rotor yoke. The rotor core 26 also has teeth 27, which extend toward the main rotor 22 and are arranged to be spaced from each other. The teeth 27 are arranged on the outside of the rotor core 26. Furthermore, the teeth 27 are equally spaced along the circumference of the rotor core 26. The remaining part of the rotor core 26, apart from the teeth 27, has the shape of a ring. The ring of rotor core 26 has a smaller extension along the longitudinal axis z than along a radial direction r.

[0041] The permanent magnet 24 is arranged along the longitudinal axis z between the rotor core 26 and the main rotor 22. The teeth 27 of the rotor core 26 are in direct contact with the main rotor 22. This means that the permanent magnet 24 is not arranged between the teeth 27 of the rotor core 26 and the main rotor 22. In the assembled state, the teeth 27 extend through the gaps between the further permanent magnets 29 toward the main rotor 22. In addition, the permanent magnet 24 with the further permanent magnets 29 is in direct contact with the main rotor 22 in the assembled state. The individual components of the rotor 20 may be joined together by adhesive bonding.

[0042] When assembled, the further permanent magnets 29 are each flush with a longer base of the base area of a claw 32 of the main rotor 22. In the assembled state, the teeth 27 are also in direct contact with a shorter base of the base area of a claw 32. This is why the number of the further permanent magnets 29 is equal to the number of the pole pairs of the main rotor 22. Thus, during operation of the electric machine 21, the magnetic flux through claws 32 may extend further through the teeth 27 and the rotor core 26. This increases the magnetic flux density of the rotor 20.

[0043] The further auxiliary rotor 25 has the same structure as the auxiliary rotor 23 and is mounted on the main rotor 22 in the opposite direction as compared to the auxiliary rotor 23. The main rotor 22 is arranged along the longitudinal axis z between the auxiliary rotor 23 and the further auxiliary rotor 25. Thus, the permanent magnet 24 of the further auxiliary rotor 25 is arranged between the rotor core 26 of the further auxiliary rotor 25 and the main rotor 22. The auxiliary rotor 23 and the further auxiliary rotor 25 are arranged at opposite end faces 33 of the main rotor 22. Since the further permanent magnets 29 of the further auxiliary rotor 25 are also adapted to the claws 32 of the main rotor 22, the further auxiliary rotor 25 is turned around the longitudinal axis z by an angle relative to the auxiliary rotor 23.

[0044] The exemplary embodiment shown in FIG. 1A has the advantage that a large part of the surface area between the rotor core 26 and the main rotor 22 is filled by the permanent magnet 24 including the further permanent magnets 29. Thus, the permanent magnet 24 including the further permanent magnets 29 has a large volume, which results in an increased magnetic flux density of the main rotor 22.

[0045] FIG. 1B shows the exemplary embodiment of the permanent magnet 24 with the further permanent magnets 29 from FIG. 1A.

[0046] FIG. 1C shows the exemplary embodiment of the auxiliary rotor 23 from FIG. 1A. The permanent magnet 24 is connected to the further permanent magnets 29 including the rotor core 26. The teeth 27 of the rotor core 26 extend into the spaces between the further permanent magnets 29. Here, the teeth 27 are arranged to be spaced apart from the further permanent magnets 29. This means that the teeth 27 are not in direct contact with the further permanent magnets 29. The teeth 27 extend further along the longitudinal axis z than the permanent magnet 24 and the further permanent magnets 29.

[0047] FIG. 1D shows the embodiment of the rotor 20 from FIG. 1A. In contrast to the illustration in FIG. 1A, FIG. 1D shows the auxiliary rotor 23 and the further auxiliary rotor 25 in the assembled state.

[0048] FIG. 2A shows a further exemplary embodiment of the rotor 20. As in FIG. 1A, individual components of the rotor 20 are shown separately for better understanding. In contrast to the exemplary embodiment in FIG. 1A, the permanent magnet 24 has a different shape. In the exemplary embodiment in FIG. 2A, the permanent magnet 24 has the same shape as the permanent magnet 24 with the further permanent magnets 29 in FIG. 1A. This means that the permanent magnet 24 is formed in one piece. Furthermore, the further permanent magnet 24 has an area that has the shape of a ring. In addition, the permanent magnet 24 has the overall shape of a ring, which has recesses 28 along its outer circumference. The recesses 28 each extend partially from the outer circumference of the permanent magnet 24 in the direction of the longitudinal axis z through the permanent magnet 24. This means that the recesses 28 each extend along a radial direction r.

[0049] Compared to the exemplary embodiment shown in FIG. 1, the exemplary embodiment shown in FIG. 2A has a higher mechanical stability because the permanent magnet 24 has a higher mechanical stability. The latter is a one-piece construction and no further permanent magnets 29 are attached to the permanent magnet 24. This increases the mechanical stability of the permanent magnet 24. In addition, the rotor 20 shown in FIG. 2A has the same advantage as the rotor 20 shown in FIG. 1A, namely that the auxiliary rotor 23 and the further auxiliary rotor 25 increase the magnetic flux density in the main rotor 22.

[0050] FIG. 2B shows the exemplary embodiment of the permanent magnet 24 from FIG. 2A.

[0051] FIG. 2C shows the exemplary embodiment of the auxiliary rotor 23 from FIG. 2A. The permanent magnet 24 is connected to the rotor core 26. The teeth 27 of the rotor core 26 extend through the recesses 28. In this arrangement, the teeth 27 are arranged to be spaced apart from the permanent magnet 24. This means that the teeth 27 are not in direct contact with the permanent magnet 24. The teeth 27 extend further along the longitudinal axis z than the permanent magnet 24.

[0052] FIG. 2D shows the exemplary embodiment of the rotor 20 from FIG. 2A. In contrast to FIG. 2A, the auxiliary rotor 23 and the further auxiliary rotor 25 are shown in FIG. 2D in their assembled state.

[0053] FIG. 3A shows a further exemplary embodiment of the rotor 20. As in FIG. 1A, individual components of the rotor 20 are shown separately for better understanding. In contrast to the exemplary embodiment in FIG. 2A, the permanent magnet 24 has a different shape. The permanent magnet 24 has the shape of a ring. The remaining structure of the rotor 20 does not differ from the structure shown in FIG. 1A.

[0054] In this exemplary embodiment, the permanent magnet 24 also exhibits high mechanical stability. It can also be easily manufactured.

[0055] FIG. 3B shows the exemplary embodiment of the permanent magnet 24 from FIG. 3A.

[0056] FIG. 3C shows the exemplary embodiment of the auxiliary rotor 23 from FIG. 3A. The permanent magnet 24 is connected to the rotor core 26. The teeth 27 of the rotor core 26 are arranged around the outer circumference of the permanent magnet 24. The permanent magnet 24 is not arranged in the spaces between the teeth 27. The teeth 27 extend further along the longitudinal axis z than the permanent magnet 24.

[0057] FIG. 3D shows the exemplary embodiment of the rotor 20 from FIG. 3A. In contrast to the illustration in FIG. 3A, the auxiliary rotor 23 and the further auxiliary rotor 25 are shown in FIG. 3D in their assembled state.

[0058] FIG. 4A shows an exemplary embodiment of the electric machine 21. The electrical machine 21 has a stator 30 with a distributed winding 38. The winding 38 is arranged in grooves 37 of the stator 30. The grooves 37 are worked in a stator plate 36. The winding heads 31 of the winding 38 of the stator 30 protrude from the stator plate 36 on opposite sides. The area between the winding heads 31 of the stator 30 is the active length 34, which can be used to generate the torque. The rotor 20 is arranged in the stator 30. Here, the main rotor 22 ends with the active length 34 of stator 30. This means that the main rotor 22 extends along the longitudinal axis z as far as the area of the stator 30 between the winding heads 31. Adjacent to the winding heads 31, the auxiliary rotor 23 and the further auxiliary rotor 25 are arranged. This means that in a radial direction r the auxiliary rotor 23 is arranged next to the winding heads 31. The auxiliary rotor 23 has the permanent magnet 24 and the rotor core 26. The permanent magnet 24 is arranged here along the longitudinal axis z between the rotor core 26 and the main rotor 22.

[0059] FIG. 4B is a side view of the exemplary embodiment of the electrical machine 21 from FIG. 4A. The winding heads 31 protrude from the stator plate 36 on opposite sides. The area between the winding heads 31 along the longitudinal axis z is the active length 34 of the electrical machine 21.

[0060] FIG. 5 shows a schematic cross-section through a part of an exemplary embodiment of the electric machine 21. The cross-section through the electrical machine 21 extends along the longitudinal axis z. That part of the electrical machine 21 is shown which is on one side of the longitudinal axis z. The rotor 20 is arranged on a shaft 35 of the electrical machine 21. The shaft 35 extends parallel to the longitudinal axis Z. Along the longitudinal axis z, the main rotor 22 is arranged between the auxiliary rotor 23 and the further auxiliary rotor 25. The stator 30 is arranged around the main rotor 22. This means that the stator 30 is arranged above the main rotor 22 in this view. The winding heads 31 protrude from the stator plate 36 on opposite sides. The length of the main rotor 22 along the longitudinal axis z corresponds to the active length 34 of the stator 30. The auxiliary rotor 23 and the further auxiliary rotor 25 are arranged below the winding heads 31 in this view. Here, the auxiliary rotor 23 and the further auxiliary rotor 25 extend along the longitudinal axis z approximately as far as the winding heads 31.

[0061] FIG. 6A shows an exemplary embodiment of the stator 30. The stator 30 has a stator plate 36 with grooves 37 incorporated therein. The electric winding 38 of the stator 30 is arranged in the grooves 37. The winding heads 31 protrude from the stator plate 36.

[0062] FIG. 6B shows the exemplary embodiment of the stator 30 from FIG. 6A without the electric winding 38. A cross-section through the stator 30 is shown, said cross-section being perpendicular to the longitudinal axis z. The stator plate 36 has a large number of grooves 37, which are open towards the inside of the stator 30.

[0063] FIG. 7 shows a detail of an exemplary embodiment of the electric machine 21. A section through a plane is shown in which the longitudinal axis z extends. The rotor 20 is placed inside the stator 30. The stator 30 has the electric winding 38, with the winding heads 31 protruding from the stator plate 36 on opposite sides. The main rotor 22 is arranged along the active length 34 of stator 30. The claws 32 of the main rotor 22 are arranged around the excitation coil 39. The auxiliary rotor 23 and the further auxiliary rotor 25 are arranged on opposite sides of the main rotor 22. The auxiliary rotor 23 and the further auxiliary rotor 25 each have the permanent magnet 24 and the rotor core 26. The rotor core 26 comprises the teeth 27. The auxiliary rotor 23 and the further auxiliary rotor 25 are each attached to the main rotor 22.