Rotor for a permanently excited synchronous machine, such an electric machine and motor vehicle

Abstract

A rotor (10) of an electric machine (11) designed as a permanently excited synchronous machine, wherein: the rotor (10) has a rotor main body (13) with pocket-like recesses (14) open radially on the outside and permanent magnets (15) positioned in the recesses (14); the rotor (10) has poles (12) which, viewed in the circumferential direction, are arranged alternately next to one another and form pole pairs; at least one permanent magnet group consisting of permanent magnets (15) which are arranged in recesses (14) positioned in a V-shape and diverge radially outwards is formed in the region of each pole (12); the rotor main body (13) carries a bandage (16) on the outer circumference; the rotor main body (13) has material recesses (20) in the region of the q-axes of its poles (12) adjacent to the pocket-like recesses (14) which are open radially outwards, in such a way that the rotor main body (13) is shorter or offset radially inwards at a distance from the bandage (16) in the region of the q-axes (19) of its poles (12).

Description

[0001] ROTOR FOR A PERMANENTLY EXCEEDED SYNCHRONOUS MACHINE, A SUCH ELECTRIC MACHINE AND MOTOR VEHICLE

[0002] The invention relates to a rotor of an electric machine designed as a permanent magnet synchronous machine. Furthermore, the invention relates to an electric machine and a motor vehicle.

[0003] The basic structure of an electric machine is well-known from practical experience. An electric machine has a housing and a stator. The stator is also called the stator. Furthermore, an electric machine has a rotor. The rotor is also called the runner. The rotor is mounted to rotate within the housing.

[0004] DE 10 2020 103 868 A1 discloses a rotor of an electric machine with a rotor body, wherein permanent magnets are positioned in radially outwardly open recesses of the rotor body. The rotor has poles that form pole pairs. In the region of each pole, at least one group of permanent magnets is formed from magnets arranged in V-shaped recesses.

[0005] US 6 891 272 B3 discloses a further rotor of an electric machine, wherein permanent magnets are arranged in V-shaped recesses in the region of each pole of the rotor, forming a respective permanent magnet group.

[0006] DE 10 2021 126626 A1 discloses a rotor of an electric machine with permanent magnets arranged in recesses of a rotor body.

[0007] DE 10 2013 020461 A1 discloses another rotor of an electric

[0008] Machine with permanent magnets arranged in recesses.

[0009] DE 10 2019 214 434 A1, DE 10 2017 218 152 A1 and EP 3 107 192 A1 disclose further prior art. To date, it has been difficult to provide a rotor for an electric machine designed as a permanent magnet synchronous machine that exhibits high speed stability, particularly at rotational speeds and thus peripheral or surface velocities exceeding 150 m / s without the risk of damage. Therefore, there is a need for a rotor for an electric machine designed as a permanent magnet synchronous machine that provides high torque and high power density at high rotational speeds and thus high peripheral or surface velocities.

[0010] surface speed can be operated.

[0011] The object of the invention is to provide a rotor for an electric machine designed as a permanent magnet synchronous machine, which exhibits high torque density and high speed stability. Furthermore, an electric machine with such a rotor and a motor vehicle with an electric machine comprising such a rotor are to be provided. This object is achieved by a rotor according to claim 1, by an electric machine according to claim 14, and by a motor vehicle according to claim 15.

[0012] The rotor according to the invention has a rotor body with radially outwardly open, pocket-like recesses and permanent magnets positioned in the recesses. The rotor according to the invention has poles that are arranged alternately next to each other in the circumferential direction and form pole pairs, wherein in the region of each pole at least one group of permanent magnets is formed from permanent magnets arranged in V-shaped recesses that diverge radially outwards. The rotor body of the rotor according to the invention carries a bandage on its outer circumference, wherein the rotor body has material recesses in the region of the q-axes of its poles adjacent to the radially outwardly open, pocket-like recesses, such that the rotor body is shortened or offset radially inwards at a distance from the bandage in the region of the q-axes of its poles.

[0013] The invention provides a rotor that can provide high torque and thus high power density at high rotational speeds and therefore high circumferential speeds or surface speeds, as well as at low mass, and which therefore has high speed stability.

[0014] By having material cutouts in the rotor body adjacent to the radially outwardly open, pocket-like recesses along its q-axes at its poles, the angle between the V-shaped recesses, at which they diverge radially outwards, can be increased. This allows for an increase in the power output of the electric machine, the torque it can provide, and the maximum rotational speed, and thus the maximum circumferential speed or surface speed. Furthermore, the stress on the bandage located on the outer circumference of the rotor body is reduced. Overall, the rotor's speed stability can be improved.

[0015] Preferably, a paramagnetic filling material is arranged in the material recesses of the rotor body in the region of the q-axes of its poles. In particular, the paramagnetic filling material connects radially to the outer edges of the permanent magnets arranged in the V-shaped recesses and preferably extends into these recesses. This makes it possible to reduce the stiffness discontinuity in the contact surface of the bandage on the outer circumference of the rotor body and thus also to reduce the load on the bandage, thereby further increasing the rotational speed capability of the rotor. At high rotational speeds and thus high circumferential or surface speeds, high torques can also be provided without increasing the mass, and consequently, a high power density.Preferably, the edges of the permanent magnets arranged in the V-shaped recesses have a chamfer or rounding in the area of ​​the radially outer end of the same, which runs adjacent to an outer circumference of the rotor body, and / or in the area of ​​the radially inner end of the same, which runs adjacent to a d-axis of the respective pole of the rotor.

[0016] In particular, the edges of the permanent magnets at both their radially outer and radially inner ends each have a chamfer or rounding, all of which are identical with the same chamfer height or radius of curvature. This also makes it possible to increase the angle at which the V-shaped recesses of each pole diverge radially outwards. The permanent magnets can be lengthened. In this way, the magnetic mass of the rotor can be increased, thereby raising the power density and the available torque. At the same time, the stress on the drum is reduced due to the larger angles of the V-shaped diverging recesses, as the mass within the drum that is not part of the rotor body is reduced. Consequently, this ensures a high maximum rotational speed and thus a high maximum peripheral speed.Surface velocity possible.

[0017] Preferably, another permanent magnet is arranged in the region of each pole between the permanent magnets arranged in the V-shaped recesses. This allows the magnetic mass to be further increased in order to further increase the available torque and power density.

[0018] Preferred embodiments of the invention are set forth in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. Figure 1 shows a schematic section of a first rotor of an electric machine designed as a permanent magnet synchronous machine, which serves as a drive unit in a motor vehicle;

[0019] Fig. 2 shows a schematic section of a second rotor of an electric machine designed as a permanent magnet synchronous machine, which serves as a drive unit in a motor vehicle;

[0020] Fig. 3 shows a schematic section of a third rotor of an electric machine designed as a permanent magnet synchronous machine, which serves as a drive unit in a motor vehicle;

[0021] Fig. 4 shows a motor vehicle with an electric machine serving as a drive unit.

[0022] Fig. 1 shows a section of a rotor 10 of an electric machine 11 designed as a permanent magnet synchronous machine. The electric machine 11 is preferably designed as a drive component of a motor vehicle 100, namely a passenger car designed as a hybrid vehicle or electric vehicle.

[0023] Radially, a stator (not shown) of the electric machine 11 is attached to the outer edge of the rotor 10. The rotor 10 and the stator are housed in a casing (not shown) of the electric machine 11, with the rotor 10 being rotatably mounted in the casing of the electric machine 11.

[0024] Fig. 1 shows a section of the rotor 10 in the region of a pole 12 of the rotor 10, where several poles 12 are arranged side by side in the circumferential direction and form pole pairs. Two poles each form a pole pair. The circumferential extent of a pole 12 is 36072p. p corresponds to the number of pole pairs of the rotor 10. The rotor 10 has a rotor body 13 with radially open, pocket-like recesses 14. The pocket-like recesses 14 accommodate permanent magnets 15.

[0025] In the area of ​​each pole 12 of the rotor 10, at least two recesses 14 are positioned in a V-shape relative to each other and accommodate permanent magnets 15, wherein the permanent magnets 15 and thus the V-shaped recesses 14 accommodating the permanent magnets 15 diverge radially outwards.

[0026] The rotor 10 has a bandage 16 that rests against the outer circumference 17 of the rotor base body 13. The rotor base body 13 therefore carries the bandage 16 on its outer circumference 17.

[0027] As already explained, the rotor 10 has several poles 12, which are arranged alternately next to each other in the circumferential direction and form pole pairs. Fig. 1 shows such a pole 12, with its so-called d-axis 18 extending in the circumferential center of the pole 12. At outer circumferential positions of the pole 12, the respective pole 12 is bounded by so-called q-axes 19.

[0028] The rotor body 13 has material recesses 20 in the region of the q-axes 19 of its poles 12 adjacent to the radially outward open, pocket-like recesses 14, namely adjacent to the radially outer ends of these V-shaped, pocket-like recesses 14, such that the rotor body 13 is shortened or offset radially inwards at a distance from the bandage 16 in the region of the q-axes 19 of its poles 12.

[0029] The rotor body 19 therefore does not touch the bandage 16 in the area of ​​the q-axes 19 of its poles 12.

[0030] The material recesses 20 of the rotor body 13 in the area of ​​its q-axes 19 of its poles 12 make it possible to increase an angle a, which the V-shaped recesses 14 positioned relative to each other enclose and thus the permanent magnets 15 positioned in the recesses 14, by up to 20% compared to rotors of permanent magnet excited synchronous machines known from practice.

[0031] This allows the magnetic mass of the permanent magnets 15 positioned in the recesses 14 to be increased, thereby increasing the power density and the available torque.

[0032] Furthermore, the load on the bandage 16 is reduced, resulting in a high maximum rotational speed and thus a high circumferential speed.

[0033] Surface speed can be provided at high torque and high power density. The rotor 10 according to the invention has a high speed stability.

[0034] Preferably, the material recesses 20 of the rotor base body 13, which are formed in the region of the q-axes 19 of the poles 12, are filled with a paramagnetic filling material 21. This paramagnetic filling material 21 can be, for example, plastic or aluminum.

[0035] Preferably, the material recesses 20 in the region of the q-axes 19 of the poles 12 of the rotor 10 are completely filled with the paramagnetic filling material 21, so that the paramagnetic filling material 21 extends to the outer circumference 17 of the rotor body 13 and the bandage 16 contacts the filling material 21. This reduces the stiffness step in the contact surface for the bandage 16, thereby reducing the load on the bandage 16 and thus increasing the maximum rotational speed and therefore the maximum circumferential speed or surface speed of the rotor, and thus its speed stability at high power density and high torques.As shown, the paramagnetic filling material connects radially to the outer edges of the permanent magnets 15 arranged in the V-shaped recesses 14 and preferably extends into the V-shaped recesses 14 at least partially in the region of the radially outer ends of the permanent magnets 15.

[0036] The permanent magnets 15 arranged in the V-shaped recesses 14 have edges 22 in the region of their radially outer end and / or in the region of their radially inner end, which have or bear a chamfer or rounding 23. In particular, it is provided that the permanent magnets 15 arranged in the V-shaped recesses 14 each have a chamfer or rounding 23 in the region of all their radially inner and radially outer edges 22, all of which are formed identically with the same chamfer height or the same radius of curvature.

[0037] The chamfer height or radius of curvature is in particular between 7% and 50% of the thickness or height of the permanent magnets 15, wherein the thickness or height of the permanent magnets 15 extends perpendicular to the extension of the longitudinal central axis of the permanent magnets 15 or of the recesses 14 receiving the permanent magnets 15.

[0038] Preferred are radii of curvature between 1 mm and 5 mm or chamfer heights between 2 mm and 4 mm.

[0039] Figures 2 and 3 show further developments of the rotor 10 of Figure 1. To avoid unnecessary repetition, the same reference numerals are used for the embodiments in Figures 2 and 3 as for the embodiment in Figure 1. Only those details that distinguish the embodiments in Figures 2 and 3 from the embodiment in Figure 1 are discussed below. The embodiments in Figures 2 and 3 have in common that, in the region of each pole 12, between the V-shaped recesses 14, there is a further recess 24 with an additional permanent magnet 25 arranged in this further development 24. In Figure 4, this further recess 24 is open radially on the outside, and the permanent magnet 25 arranged in this radially open recess 24 has a convexly curved contour on both the radial inside and radial outside. Radially on the outside, the permanent magnet 25 of Figure 4...2 the outer circumference 17 of the rotor base body 16 and thus forms a contact surface for the bandage 16 in sections.

[0040] In Fig. 3, the recess 24 which receives the further magnet 25 is closed radially on the outside.

[0041] The additional magnet 25 allows the magnetic mass, and thus the power density and the available torque, to be further increased. This is possible at high maximum rotational speeds and therefore high maximum peripheral speeds or surface speeds.

[0042] The invention allows the magnetic mass per pole 12, and thus the available torque and power density, to be increased. This is possible at high maximum rotational speeds and therefore high maximum circumferential speeds or surface speeds. Stress peaks in the bandage 16 can be avoided.

[0043] Although in the illustrated embodiments only two V-shaped recesses 14 for receiving permanent magnets 15 are shown at each pole 12, several such V-shaped recesses arranged to each other can be present at each pole 12, which in turn serve to receive permanent magnets.

[0044] Preferably, the rotor has between two and five pole pairs. The outer diameter of the rotor body 16 is between 90 mm and 170 mm, preferably between 110 mm and 170 mm, and particularly preferably between 120 mm and 170 mm. The inner diameter of the rotor body 13 is between 10 mm and 110 mm, preferably between 30 mm and 80 mm, and particularly preferably between 40 mm and 80 mm.

Claims

Patent claims 1. Rotor (10) of an electric machine (11) designed as a permanent magnet synchronous machine, wherein the rotor (10) has a rotor body (13) with radially outwardly open, pocket-like recesses (14) and permanent magnets (15) positioned in the recesses (14), wherein the rotor (10) has poles (12) which are arranged alternately next to each other in the circumferential direction and form pole pairs, wherein in the region of each pole (12) at least one group of permanent magnets (15) arranged in V-shaped recesses (14) is formed, which diverge radially outwards, wherein the rotor body (13) carries a bandage (16) on its outer circumference, wherein the rotor body (13) has material recesses (20) adjacent to the radially outwardly open, pocket-like recesses (14) in the region of the q-axes of its poles (12), such thatthat the rotor body (13) is shortened or offset radially inwards in the region of the q-axes (19) of its poles (12) at a distance from the bandage (16).

2. Rotor (10) according to claim 1 , characterized in that the rotor base body (13) is shortened radially inwards in the region of the q-axes (19) of its poles (12) at a distance to the bandage (16) such that the rotor base body (13) does not touch the bandage (16) in the region of the q-axes (19).

3. Rotor (10) according to claim 1 or 2, characterized in that a paramagnetic filling material (21) is arranged in the material recesses (20) of the rotor base body (13) in the region of the q-axes (19) of its poles (12).

4. Rotor (10) according to claim 3, characterized in that the paramagnetic filling material (21) completely fills the material recesses (20) of the rotor base body (13) in the region of the q-axes (19) of the poles (12).

5. Rotor (10) according to claim 3 or 4, characterized in that the paramagnetic filling material (21) connects radially outside to the permanent magnets (15) arranged in the V-shaped recesses (14).

6. Rotor (10) according to claim 3, 4 or 5, characterized in that the paramagnetic filling material (21) extends into the V-shaped recesses (14).

7. Rotor (10) according to one of claims 1 to 6, characterized in that edges (22) of the permanent magnets (15) arranged in the V-shaped recesses (14) have a chamfer or rounding (23) in the region of the radially outer end of the same, which is adjacent to an outer circumference (17) of the rotor body (13), and / or in the region of the radially inner end of the same, which is adjacent to a d-axis (18) of the respective pole (12) of the rotor (10).

8. Rotor (10) according to claim 7, characterized in that the edges (22) of the permanent magnets (15) in the region of the radially outer end of the same and in the region of the radially inner end of the same each have a chamfer or rounding (23) which are all formed in the same way with the same chamfer height or the same radius of curvature.

9. Rotor (10) according to claim 8, characterized in that the chamfer height or the radius of curvature corresponds to between 7% and 50% of the thickness of the respective permanent magnets (15).

10. Rotor (10) according to one of claims 1 to 9, characterized in that in the area of ​​each pole (12) between the permanent magnets (15) arranged in the V-shaped recesses (14) a further permanent magnet (25) is arranged.

11. Rotor (10) according to claim 10, characterized in that the respective further permanent magnet (25) is convexly curved radially inwards and radially outwards, is arranged in a further radially outwards open recess (24) and touches the bandage (16).

12. Rotor (10) according to one of claims 1 to 11, characterized in that it has between two and five pole pairs.

13. Rotor (10) according to one of claims 1 to 12, characterized in that an outer diameter of the rotor base body (13) is between 90 mm and 170 mm, preferably between 110 mm and 170 mm, particularly preferably between 120 mm and 170 mm, and an inner diameter of the rotor base body (13) is between 10 mm and 110 mm, preferably between 30 mm and 80 mm, particularly preferably between 40 mm and 80 mm.

14. Electric machine (11 ) with a rotor (10) according to one of claims 1 to 12, which is designed as a drive device of a motor vehicle, namely a hybrid vehicle or electric vehicle.

15. Motor vehicle (100), namely hybrid vehicle or electric vehicle, with an electric machine (11) serving as a propulsion device, which has a rotor (10) according to one of claims 1 to 12.

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