Rotor for a rotating electric machine and rotating electric machine

Abstract

The invention relates to a rotor (1) for a rotary electric machine, which rotor is able to interact with a stator (3) of the rotary electric machine and to rotate about an axis of rotation (A), the rotor (1) comprising: - a rotor body (7) comprising a cavity (10); - a permanent magnet (4) partly disposed in the cavity (10), the permanent magnet (4) having a first length (13) in the direction of the axis of rotation (A) between a first face (11) of the permanent magnet (4) at a first end (14) of the permanent magnet (4) and a second face (12) of the permanent magnet (4) at a second end (15) of the permanent magnet (4), the rotor body (7) comprising a portion (16) for holding the permanent magnet (4), the permanent magnet (4) being borne on this portion and able to face radially the stator (3), the portion (16) for holding the permanent magnet having a second length (19) in the direction of the axis of rotation (A) between a third face (17) of the holding portion and a fourth face (18) of the holding portion, the first length (13) of the permanent magnet (4) being greater than the second length (19) of the holding portion (16). The invention also relates to a rotary electric machine fitted with such a rotor.

Description

TECHNICAL FIELD

[0001] The present invention relates to a rotor for a rotary electric machine and to a rotary electric machine equipped with such a rotor. BACKGROUND

[0002] A rotor for a rotary electric machine is known from patent application US 2015 / 0364959 A1, which is capable of interacting with a stator of a rotary electric machine and of rotating with respect to a rotation axis, the rotor comprising:

[0003] - a rotor body having a cavity,

[0004] - a permanent magnet disposed in the cavity, the permanent magnet having a first length in the direction of the rotation axis,

[0005] the rotor body comprises a portion for holding the magnet, the permanent magnet being supported on this portion and being capable of facing the stator, the portion for holding the magnet having a second length in the direction of the rotation axis between a first face of the holding portion and a second face of the holding portion,

[0006] the first length of the permanent magnet is equal to or less than the second length of the holding portion.

[0007] The drawback of such a rotor is that a magnetic loss is generated between the permanent magnet and the stator. In particular, the permanent magnets used generally comprise smooth (e.g. with rounded corners) edge corners at their ends. These smooth edge corners are related to permanent magnet manufacturing constraints. The permanent magnets having such smooth edge corners have the effect of locally increasing the air gap between the rotor and the stator. This increase in the air gap has the drawback of increasing the magnetic loss and thus of reducing the power of the electric machine. SUMMARY

[0008] The present invention seeks to eliminate all these drawbacks or some of them.

[0009] The present invention relates to a rotor for a rotary electric machine, which is capable of interacting with a stator of a rotary electric machine and of rotating with respect to a rotation axis, the rotor comprising:

[0010] - a rotor body having a cavity,

[0011] - a permanent magnet disposed partially in the cavity, the permanent magnet having a first length in the direction of the rotation axis between a first face of the permanent magnet at a first end of the permanent magnet and a second face of the permanent magnet at a second end of the permanent magnet,

[0012] the rotor body comprises a portion for holding the permanent magnet, the permanent magnet being supported on this portion and being capable of facing radially the stator, the portion for holding the permanent magnet having a second length in the direction of the rotation axis between a third face of the holding portion and a fourth face of the holding portion,

[0013] The first length of the permanent magnet is greater than a second length of the holding portion.

[0014] The use of a permanent magnet longer than the holding portion of the rotor body makes it possible to improve the performance of a rotating electrical machine in which the rotor is installed. In particular, the permanent magnet has an engagement surface at its end between two surfaces, for example between two flat surfaces. The engagement surface is for example a rounded or chamfered corner. The use of a magnet longer than the holding portion of the rotor body makes it possible to displace the entire such engagement surface or a portion thereof outside the holding portion. This reduces or even avoids a significant increase in the air gap between the stator and the rotor at the end of the rotor body. The magnetic losses are thus reduced and the performance of the rotating electrical machine is improved.

[0015] According to an additional feature of the invention, the first end of the permanent magnet projects from the cavity a third length in the direction of the rotation axis relative to one of the third face of the holding portion and the fourth face of the holding portion.

[0016] According to an additional feature of the invention, the second end of the permanent magnet projects from the cavity a fourth length in the direction of the rotation axis relative to the other of the third face of the holding portion and the fourth face of the holding portion.

[0017] The permanent magnets projecting from the holding portion of the rotor body at both ends allow the magnetic losses at these ends to be reduced and thus improve the performance of the rotating electrical machine even more.

[0018] The third length and the fourth length are identical or different.

[0019] According to an additional feature of the invention, the rotor comprises a first closed end plate comprising a first recess receiving the first end of the permanent magnet.

[0020] The use of such a first end plate makes it easier to manufacture the rotor. In particular, because the first recess is manufactured in the end plate before assembly of the rotor, various materials can be used to manufacture the first end plate. For example, it is not necessary to heat the rotor during assembly of the rotor. The absence of such a possible heat input makes it possible to avoid deformation of the components of the rotor and demagnetization of the magnets during assembly.

[0021] According to an additional feature of the invention, the rotor comprises a second closed end plate comprising a second recess receiving the second end of the permanent magnet.

[0022] The use of closed end plates makes it possible to hold the body of the rotor together, in particular when this body is formed from a stack of laminations. In order to ensure such holding, fastening means such as a nut assembly can allow the first closed end plate and the second closed end plate to be fastened to the rotor body.

[0023] Moreover, the closing end plate can be used to balance the rotor, in particular by removing material from the closing end plate. The recess in the closing end plate allows to accommodate the end of the permanent magnet.

[0024] The size of the recess can be set to avoid contact with the permanent magnet during assembly of the closing end plate. Thus, the permanent magnet is not stressed during assembly of the closing end plate.

[0025] According to an additional feature of the application, the retaining portion comprises a tooth oriented circumferentially with respect to the rotation axis so as to radially retain the permanent magnet.

[0026] According to an additional feature of the application, the first end of the permanent magnet comprises, between the fifth face of the permanent magnet retained by the retaining portion and the first face of the permanent magnet, a first junction face, in particular a fillet,

[0027] The first junction face faces the stator and extends in the direction of the rotation axis by a fifth length which is 0.5 to 2 times the third length, in particular 0.6 to 1.5 times the third length.

[0028] The use of a fifth length which is 0.5 to 2 times the third length, in particular 0.6 to 1.5 times the third length, makes it possible to ensure an improvement in the performance of the rotary electric machine while limiting an increase in the axial size of the rotor.

[0029] According to an additional feature of the application, the second end of the permanent magnet comprises, between the fifth face of the permanent magnet retained by the retaining portion and the second face of the permanent magnet, a second junction face, in particular a fillet,

[0030] The second junction face faces the stator and extends in the direction of the rotation axis by a sixth length which is 0.5 to 2 times the fourth length, in particular 0.6 to 1.5 times the fourth length.

[0031] The use of a sixth length which is 0.5 to 2 times the fourth length, in particular 0.6 to 1.5 times the fourth length, makes it possible to ensure an improvement in the performance of the rotary electric machine while limiting an increase in the axial size of the rotor.

[0032] According to an additional feature of the application, the permanent magnet is a ferrite type permanent magnet.

[0033] According to an additional feature of the application, the permanent magnet is retained in the cavity by a varnish or an adhesive.

[0034] The application also relates to a rotary electric machine comprising:

[0035] - a rotor as described above,

[0036] - a stator.

[0037] According to an additional feature of the invention, the rotor is located radially inside the stator relative to the axis of rotation.

[0038] The rotating electric motor may include power electronic components capable of connecting to the vehicle's onboard network. These power electronic components may include, for example, an inverter / rectifier that allows the vehicle's onboard network to be charged or powered by the network, depending on whether the motor operates as an electric motor or a generator.

[0039] The rotating electric motor may further include pulleys or any other devices connected to the rest of the vehicle's powertrain. For example, the motor is specifically connected via a belt to the crankshaft of the vehicle's combustion engine. As variations, the motor may be connected at other locations in the powertrain, such as at the input end of the gearbox from the perspective of transmitting torque to the vehicle's wheels, at the output side of the gearbox from the perspective of transmitting torque to the vehicle's wheels, at the gearbox itself from the perspective of transmitting torque to the vehicle's wheels, or on the front or rear axle assembly of the powertrain. Attached Figure Description

[0040] The invention can be better understood by reading the following description of examples of non-limiting embodiments of the invention and studying the accompanying drawings, in which:

[0041] - Figure 1 A partial view of a cross-section of a rotating electric motor including a rotor according to the invention is shown.

[0042] - Figure 2 It shows Figure 1 A partial view of the cross-section of the rotor of a rotating electric machine.

[0043] - Figure 3 It shows Figure 1 Another partial view of the cross-section of the rotor of the rotating electric machine in the image.

[0044] - Figure 4 It shows Figure 1 The closed end plate of the rotor of the rotating electric machine in the middle,

[0045] - Figure 5 It shows Figure 1 Another partial view of the cross-section of the rotor of the rotating electric machine in the image.

[0046] - Figure 6 It shows Figure 1 The magnet of the rotor of a rotating electric motor.

[0047] In all the accompanying drawings, the same or functionally equivalent elements are marked with the same reference numerals. The following embodiments are examples. Although the description refers to one or more embodiments, it is not necessarily true that every reference numeral refers to the same embodiment, or that these features are applicable only to a single embodiment. Individual features of different embodiments may also be combined or interchanged to provide other embodiments. Detailed Implementation

[0048] Figure 1 A partial view of a motor with a rotation axis A is shown. For better readability, some parts are not depicted.

[0049] The motor includes a rotor 1 and a stator 3.

[0050] The stator 3 includes, for example, the stator body 8 and the phase windings 9.

[0051] Rotor 1 includes:

[0052] - Rotor body 7 with cavity 10,

[0053] - A permanent magnet 4 is partially disposed in the cavity 10.

[0054] Permanent magnet 4 is, for example, a ferrite-type permanent magnet.

[0055] In another embodiment, the permanent magnet is a rare-earth type magnet.

[0056] In another embodiment, the permanent magnet comprises a group of magnets bonded together. The bonded magnets can be of different types, such as ferrite and rare earth types.

[0057] The permanent magnet 4 includes a first surface 11 at a first end 14 and a second surface 12 at a second end 15. A first length 13 is defined between the first surface 11 and the second surface 12 in the direction of the rotation axis A. The first surface 11 and the second surface 12 are, for example, parallel.

[0058] The rotor body 7 includes, for example, a stack of magnetic laminates. The rotor body can be mounted on a shaft not shown in the figure.

[0059] like Figure 2 As shown, the rotor body 7 includes a portion 16 for holding the permanent magnet 4. The permanent magnet 4 is supported on the holding portion 16. The support of the permanent magnet 4 on the holding portion can be direct or indirect. For example, it can be done via a plate 29 or a strip. This plate 29 is made of a material softer than the permanent magnet 4. The plate 29 is made, for example, of plastic or composite materials (especially resin filled with glass fiber). The plate 29 is positioned between the holding portion 16 and the permanent magnet 4. The plate 29 allows for improved contact between the holding portion 16 and the permanent magnet 4.

[0060] The retaining portion includes, for example, teeth 26 oriented circumferentially relative to the axis of rotation A to radially retain the permanent magnet 4. The support of the permanent magnet 4 on the retaining portion can be made on one face of the teeth 26.

[0061] In another embodiment, not shown, the retaining portion is circumferentially continuous. The permanent magnet is thus referred to as embedded.

[0062] In the embodiment shown in the accompanying drawings, the rotor includes a plurality of permanent magnets 4, each disposed in a different cavity 10. Each permanent magnet is held by two teeth 26 in opposite circumferential directions. The cavity 10 is radially open between the two teeth 26.

[0063] The portion 16 for holding the permanent magnet 4 is radially oriented toward the stator 3. The holding portion 16 extends a second length 19 in the direction of the rotation axis A between the third surface 17 and the fourth surface 18 of the holding portion.

[0064] The small plate 29 has a length, for example, greater than or equal to the second length.

[0065] The first length 13 of the permanent magnet 4 is greater than the second length 19 of the holding portion 16.

[0066] The first end 14 of the permanent magnet 4 protrudes a third length 20 from the cavity 10 in the direction of the rotation axis A relative to one of the third surface 17 and the fourth surface 18 of the retaining portion 16.

[0067] Furthermore, the second end 15 of the permanent magnet 4 can protrude a fourth length 21 from the cavity 10 relative to the other of the third surface 17 and the fourth surface of the retaining portion 16 in the direction of the rotation axis A. Therefore, both ends 14 and 15 of the permanent magnet protrude from the retaining portion.

[0068] The length of the rotor body 7 may be equal to the second length 19 of the retaining portion 16. As seen above, the rotor body may include a stack of laminates. Each of the laminates of similar shape may thus include a small portion of the teeth 26.

[0069] like Figure 1 As shown, the rotor 1 may include a first closed end plate 22. The first closed end plate 22 includes a first recess 23 for receiving a first end 14 of the permanent magnet 4.

[0070] In addition, the rotor 1 may include a second closed end plate 24. The second closed end plate 24 includes a second recess 25 for receiving the second end 15 of the permanent magnet 4.

[0071] The first closed end plate 22 and the second closed end plate 24 can be used as balancing discs for the rotor 1. Balancing is achieved, for example, by removing material from the first closed end plate 22 and / or the second closed end plate 24.

[0072] The first closed end plate 22 and the second closed end plate 24 are made of, for example, a material with weak magnetic properties (especially aluminum) in order to avoid short-circuiting the rotor 1 magnetically.

[0073] Figure 4 One of the first closed end plate 22 and the second closed end plate 24 is shown.

[0074] The fastening device 6 allows the first closed end plate 22 and the second closed end plate 24 to be fastened to the rotor body 7. In the embodiment shown in the figures, the fastening device 6 is a screw and nut assembly. The rotor body 7 includes a first hole 27 ( Figure 2 (As shown). The first closed end plate 22 and the second closed end plate 24 include a second hole 33. The first hole 27 and the second hole 33 allow the shank of the screw of the fastening device 6 to pass through. The nut of the fastening device 6 is tightened on the screw so that the stator body 7 can be clamped between the first closed end plate 2 and the second closed end plate 24.

[0075] Figure 5 It shows Figure 3 A partial schematic detail of the permanent magnet 4 and the retaining portion 16 of the rotor 1 is shown. To enable... Figure 5 It is relatively easy to understand, and small plate 29 is not shown.

[0076] The first end 14 of the permanent magnet 4 includes a first mating surface 30 between the fifth surface 28 of the permanent magnet 4, which is held by the holding portion 16 (particularly the tooth 26), and the first surface 11 of the permanent magnet. The first mating surface 30 is, for example, a rounded corner.

[0077] The fifth surface 28 of the permanent magnet 4 is, for example, flat. Similarly, the first surface 11 of the permanent magnet is, for example, flat.

[0078] Figure 6 A permanent magnet 4 with a first mating surface 30 is shown.

[0079] The first mating surface 30 faces the stator 3 and extends a fifth length 31 in the direction of the rotation axis A. The fifth length 31 is, for example, 0.8 to 1.2 times the third length 20.

[0080] Similarly, the second end 15 of the permanent magnet 4 includes a second mating surface 34, in particular a rounded corner, between the fifth surface 28 of the permanent magnet 4 held by the holding portion 16 and the second surface 12 of the permanent magnet 4.

[0081] The second surface 12 of the permanent magnet 4 is, for example, flat.

[0082] The second mating surface 34 faces the stator 3 and extends a sixth length in the direction of the rotation axis A. The sixth length is 0.8 to 1.2 times the fourth length 21.

[0083] In another embodiment not shown, the first mating surface and / or the second mating surface is chamfered.

[0084] The permanent magnet 4 can be held in the cavity by varnish or adhesive. The first closed end plate 22 and the second closed end plate 24 may include openings 32 to allow the introduction of adhesive or varnish. The openings 32 are formed, for example, in the first closed end plate and the second closed end plate, and particularly in the first recess and the second recess, respectively.

[0085] In the embodiment shown in the accompanying drawings, the rotary motor is a rotary motor having an internal rotor 1, that is, a rotary motor in which the rotor 1 is radially located inside the stator 3 relative to the rotation axis A.

[0086] In other embodiments of the invention, the rotary motor is a rotary motor having an external rotor, that is, a rotary motor in which the rotor is located radially outside the stator relative to the axis of rotation.

Claims

1. A rotor (1) for a rotating electric motor, the rotor being capable of interacting with the stator (3) of the rotating electric motor and rotating relative to a rotation axis (A), the rotor (1) comprising: a. Rotor body (7) with cavity (10). b. A permanent magnet (4) partially disposed in the cavity (10), the permanent magnet (4) having a first length (13) in the direction of the rotation axis (A) between a first surface (11) at the first end (14) of the permanent magnet (4) and a second surface (12) at the second end (15) of the permanent magnet (4). The rotor body (7) includes a portion (16) for holding the permanent magnet (4), the permanent magnet (4) being supported on the portion and being radially oriented toward the stator (3), the portion (16) for holding the permanent magnet having a second length (19) in the direction of the rotation axis (A) between the third surface (17) and the fourth surface (18) of the holding portion. The first length (13) of the permanent magnet (4) is greater than the second length (19) of the retaining portion (16). The first end (14) of the permanent magnet (4) protrudes a third length (20) from the cavity (10) in the direction of the rotation axis (A) relative to one of the third surface (17) and the fourth surface (18) of the retaining portion (16), and The rotor (1) includes a first closed end plate (22) and a second closed end plate (24), wherein the first closed end plate (22) includes a first recess (23) that receives the first end (14) of the permanent magnet (4). The rotor body (7) includes a first hole (27); The first closed end plate (22) and the second closed end plate (24) include a second hole (33); The first hole (27) and the second hole (33) allow a fastening device (6) consisting of a set of screws and nuts to pass through.

2. The rotor (1) as described in the preceding claim, wherein, The second end (15) of the permanent magnet (4) protrudes a fourth length (21) from the cavity (10) in the direction of the rotation axis (A) relative to the third surface (17) and the fourth surface of the retaining portion (16).

3. The rotor (1) as claimed in claim 2, wherein the second closed end plate (24) includes a second recess (25) for receiving the second end (15) of the permanent magnet (4).

4. The rotor (1) as described in any one of the preceding claims, wherein, The retaining portion (16) includes teeth (26) circumferentially oriented relative to the axis of rotation (A) to radially retain the permanent magnet (4).

5. The rotor (1) as described in any one of the preceding claims, wherein, The first end (14) of the permanent magnet (4) includes a first mating surface (30) between the fifth surface (28) of the permanent magnet (4) held by the holding portion (16) and the first surface (11) of the permanent magnet (4). The first mating surface (30) faces the stator (3) and extends a fifth length (31) in the direction of the rotation axis (A), the fifth length (31) being 0.5 to 2 times the third length (20).

6. The rotor (1) as described in claim 5, wherein, The first mating surface is rounded.

7. The rotor (1) as described in claim 5, wherein, The fifth length (31) is 0.6 to 1.5 times the third length (20).

8. The rotor (1) as claimed in any one of claims 2 to 5, wherein, The second end (15) of the permanent magnet (4) includes a second mating surface (34) between the fifth surface (28) of the permanent magnet (4) held by the holding portion (16) and the second surface (12) of the permanent magnet (4). The second mating surface (34) faces the stator (3) and extends a sixth length in the direction of the rotation axis (A), the sixth length being 0.5 to 2 times the fourth length (21).

9. The rotor (1) as described in claim 8, wherein, The second mating surface is rounded.

10. The rotor (1) as described in claim 8, wherein, The sixth length is 0.6 to 1.5 times the fourth length.

11. The rotor (1) as described in any one of the preceding claims, wherein, The permanent magnet (4) is a ferrite type permanent magnet.

12. The rotor (1) as described in any one of the preceding claims, wherein, The permanent magnet (4) is held in the cavity (10) by varnish or adhesive.

13. A rotary motor, the rotary motor comprising: a. The rotor (1) as described in any of the preceding claims. b. Stator (3).

14. The motor as claimed in claim 12, wherein, The rotor (1) is located radially inside the stator (3) relative to the axis of rotation.

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