Rotating electric machine

Abstract

The invention relates to a rotating electrical machine comprising a stator assembly and a rotor assembly including a ring (8) comprising: - at least one first lateral edge (24), - a plurality of permanent magnets (28) fixed along the first lateral edge of the ring, the plurality of permanent magnets being aligned to form a first row (30); the permanent magnets of the first row comprising a first main face (32) fixed to the ring, a second main face (34) opposite the first main face, and a first lateral face (36) disposed in the vicinity of the first lateral edge; - at least one first ring (43) encircling the permanent magnets of the first row. The second main face and / or the first lateral face of the permanent magnets of the first row has a cavity (41), in which said at least one first ring (43) is housed. Figure to be published with the abbreviation: Figure 2

Description

Title of the invention: Rotating electric machine Technical field of the invention

[0001] The present invention relates to a rotating electrical machine. State of the prior art

[0002] Rotating electrical machines comprise a stator assembly and a rotor assembly pivoting relative to the stator assembly. The rotor assembly may comprise a ring gear on which permanent magnets are fixed.

[0003] When operating speeds are high, the permanent magnets can become detached due to centrifugal forces. To overcome this drawback, it is known to make a glass or carbon fiber hoop around the permanent magnets. However, this hoop reduces the size of the air gap between the permanent magnets and the internal annular face of the stator assembly. Presentation of the invention

[0004] An aim of the present invention is to ensure the fixing of the permanent magnets without reducing the dimension of the air gap. Summary of the invention

[0005] The present invention relates to a rotating electrical machine comprising a stator assembly, and a rotor assembly pivotally mounted relative to the stator assembly around an axis of rotation, the rotor assembly comprising a ring comprising: - at least one first lateral edge, - a plurality of permanent magnets fixed along the first lateral edge of the crown, the plurality of permanent magnets being aligned so as to form a first row; the permanent magnets of the first row comprising a first main face fixed to the crown, a second main face opposite the first main face and a first lateral face arranged in the vicinity of the first lateral edge; - at least a first ring surrounding the permanent magnets of the first row; characterized in that the second main face and / or the first lateral face of the permanent magnets of the first row comprises at least one cavity, and in which said at least one first ring is housed in said cavity.

[0006] Advantageously, the first ring prevents the permanent magnets from detaching. Advantageously, the cavities made on the permanent magnets allow the hooping of permanent magnets while keeping a constant air gap dimension.

[0007] The characteristics set out in the following paragraphs can, optionally- ally, be implemented. They can be implemented independently of each other or in combination with each other: - said at least one cavity opens onto the second main face and onto the first lateral face of the permanent magnets of the first row.

[0008] Advantageously, said at least one first ring can be easily removed from the cavity without damage by moving the ring in an axial direction.

[0009] The crown includes: - a second lateral edge opposite the first lateral edge, - a plurality of permanent magnets fixed along the second lateral edge, the plurality of permanent magnets being aligned and forming a second row, the permanent magnets of the second row comprising a first main face fixed to the crown, a second main face opposite the first main face and a first lateral face arranged in the vicinity of the second lateral edge, the second main face and / or the first lateral face of the permanent magnets of the second row comprises a cavity; - At least one second ring housed in said cavity of the permanent magnets of the second row; said at least one second ring surrounding the permanent magnets of the second row. - The cavity opens onto the second main face and the first lateral face of the permanent magnets of the second row. - The permanent magnets of the first row and the second row comprise a second lateral face opposite the first lateral face; the second lateral faces of at least a portion of the permanent magnets of the first row and the second row comprise at least one hole, and in which said crown comprises fixing pins fixed, on the one hand, in the holes of the permanent magnets of the first row and, on the other hand, in the holes of the permanent magnets of the second row. Advantageously, the fixing pins increase the resistance to tearing of the permanent magnets under the action of centrifugal forces exerted during the rotation of the rotor crown. In particular, the fixing pins 52 reinforce the holding of the permanent magnets in a direction perpendicular to the axial direction XX. - The cavities of the permanent magnets in the first row have a depth of between 3 and 6 millimeters. - The cavities have a width between 1.5 and 4 millimeters. - The first ring is made of non-magnetic stainless steel or composite material. - The second ring is made of non-magnetic stainless steel or a composite material. - The permanent magnets of the first row comprise a second side face opposite the first side face, the second main face and / or the second side face of the permanent magnets of the first row comprising an additional cavity; said crown further comprising an additional ring housed in the additional cavities of the permanent magnets of the first row; the additional ring surrounding the permanent magnets of the first row. The additional ring is made of non-magnetic stainless steel or composite material. Brief description of the figures

[0010] [Fig-1] is a radial sectional view of an example of a rotating electrical machine according to the invention;

[0011] [Fig.2] is a partially exploded perspective view of a crown of a rotating electrical machine according to a first embodiment;

[0012] [Fig.3] is a sectional view of the crown illustrated in [Fig.4], the section being produced according to a radial plane crossing a fixing pin;

[0013] [Fig.4] is a sectional view of a crown of a rotor assembly according to a second embodiment, the cut being made in a radial plane;

[0014] [Fig.5] is a sectional view of a crown of a rotor assembly according to a third embodiment, the cut being made in a radial plane. Detailed description of the invention

[0015] The rotating electrical machine 2 according to the invention is described below in its preferred, but non-limiting, application to an eddy current retarder and generator assembly.

[0016] With reference to [Fig. 1], the rotating electrical machine 2 comprises a stator assembly 4, and a rotor assembly 6 pivoting relative to the stator assembly around an axis of rotation X.

[0017] The rotor assembly 6 comprises a crown 8, a cylindrical sleeve 10, and bent arms or a flange connecting the crown 8 to the cylindrical sleeve 10.

[0018] The stator assembly 4 comprises an annular support 14 provided with polar cores 15 and inductor coils 16 arranged around the polar cores.

[0019] The polar cores 15 and the inductor coils 16 are distributed at regular intervals around a circle centered on a point of the axis of rotation XX. The inductor coils 16 each comprise a conductive wire wound around a core polar. The winding directions of the conductive wire alternate from one inductor coil to the next, so as to alternate the polarities of the inductors. The stator assembly 4 further comprises polar expansions 20 fixed to the free ends of the polar cores 15 by fixing screws 22 screwed into tapped holes in the polar cores.

[0020] The inductor coils 16, the polar cores 15 and the polar expansions 20 constitute the inductor of the retarder. The cylindrical sleeve 10 constitutes the armature of the retarder.

[0021] The internal face 12 of the annular support is provided with radial grooves 18 forming cores. These cores are surrounded by conductive electrical wires not shown in the figures. The cores and their windings of electrical wires form the armature of the generator.

[0022] The annular support 14 can be fixed with suitable means on the chassis of the vehicle or on the gearbox housing of the vehicle. The axis of rotation of the cylindrical sleeve 10, the central axis of the crown 8, the central axis of the annular support 14 are coaxial with the axis of rotation of the rotary shaft of the vehicle, when the eddy current retarder and generator assembly is mounted on the vehicle.

[0023] With reference to Figures 2 and 3, the crown 8 comprises a support 23, a first circular lateral edge 24 and a second circular lateral edge 26 located on the side opposite the first lateral edge.

[0024] The ring 8 further comprises a plurality of permanent magnets 28 fixed along the first lateral edge 24. The permanent magnets 28 of the ring constitute the inductor of the generator. The permanent magnets 28 are aligned so as to form a first row 30. The permanent magnets 28 of the first row each have the general shape of a block. In particular, they comprise a first main face 32 fixed to the crown, a second main face 34 opposite the first main face and directed outwards, a first lateral face 36 arranged in the vicinity of the first lateral edge 24, a second lateral face 38 opposite the first lateral face, a third lateral face 40 and a fourth lateral face 42. The second lateral face 38 is arranged in the vicinity of a central portion of the circular face of the crown. The third lateral face 40 is in contact with a preceding permanent magnet of the row. The fourth lateral face 42 is in contact with a following permanent magnet of the row.

[0025] The first lateral face 36 of the permanent magnets of the first row comprises a cavity 4L. The cavity 41 extends along the entire length of the lateral face 36. In other words, the cavity 41 extends from one end of the lateral face 36 to the other. In the preferred embodiment shown in Figures 2 and 3, the cavity 41 opens onto both the space opposite the first lateral face 36 and on the space opposite the second main face 34. The cavity 41 is arranged in the vicinity of the first lateral edge 24 of the crown.

[0026] In other words, the cavity 41 is formed on the upper lateral edge of the permanent magnets.

[0027] In other words, the cavity 41 has been arranged on the edge formed between the first lateral face 36 and the second main face 34. According to a variant not shown, the cavity 41 is formed by a groove opening only onto the first lateral face 36.

[0028] According to another variant not shown, the cavity 41 is formed by a groove opening only onto the second main face 34.

[0029] The cavities 41 of the permanent magnets of the first row have a depth P of between 3 and 6 millimeters.

[0030] The cavities 41 have a width L of between 1.5 and 4 millimeters.

[0031] The crown 8 also comprises a first ring 43 housed in the cavities 41 of the permanent magnets of the first row. The first ring 43 surrounds the permanent magnets of the first row 30.

[0032] The first ring 43 is, for example, made of non-magnetic stainless steel or a composite material.

[0033] Advantageously, the first ring 43 prevents the permanent magnets from detaching. Advantageously, the cavities 41 made on the permanent magnets allow the permanent magnets to be hooped together while maintaining a constant air gap dimension. The air gap is here the space delimited between the permanent magnets 28 of the ring 8 and the internal face 12 of the annular support 14.

[0034] Advantageously, maintaining a constant air gap makes it possible to avoid fluctuations in the machine torque.

[0035] Advantageously, maintaining a constant air gap makes it possible to avoid contact between the rotor and the stator. The crown 8 also includes a plurality of permanent magnets 28 fixed along the second lateral edge 26. The permanent magnets 28 are aligned so as to form a second row 44.

[0036] In the embodiment shown, the permanent magnets 28 of the second row 44 are identical to the permanent magnets of the first row. They will not be described in detail a second time. The first lateral face 36 of the permanent magnets of the second row 44 is arranged in the vicinity of the second lateral edge 26 of the crown. The second lateral face 38 of the permanent magnets of the second row 44 is in contact with the second side face 38 of the permanent magnets of the first row.

[0037] The first lateral face 36 of the permanent magnets of the second row 44 comprises a cavity 46.

[0038] The cavity 46 is similar to the cavity 41 of the permanent magnets of the first row 30. It will not be described a second time. It is arranged in the vicinity of the second lateral edge 26 of the crown.

[0039] According to a variant not shown, the cavity 46 is formed by a groove opening only onto the first lateral face 36.

[0040] According to another variant not shown, the cavity 46 is formed by a groove opening only onto the second main face 34.

[0041] The crown 8 further comprises a second ring 48 housed in the cavity 46 and surrounding the permanent magnets of the second row.

[0042] The second ring 48 is for example made of non-magnetic stainless steel or a composite material.

[0043] In the embodiment illustrated in Figures 2 and 3, the second lateral face 38 of the permanent magnets of the first row 30 and the second lateral face 38 of the permanent magnets of the second row 44 comprise two holes 50 spaced from each other, and two fixing pins 52 each arranged and fixed in a hole 50 of a permanent magnet of the first row 30 and in a hole 50 of a permanent magnet of the second row 44.

[0044] The holes 50 and the fixing pins 52 are for example arranged halfway up the thickness of the permanent magnets. The fixing pins 52 are, for example, made of a non-magnetic stainless steel or a composite material.

[0045] Advantageously, the fixing pins increase the resistance to tearing of the permanent magnets under the action of the centrifugal forces exerted during the rotation of the crown of the rotor assembly.

[0046] In particular, the fixing pins 52 reinforce the holding of the permanent magnets in a direction perpendicular to the axial direction XX.

[0047] Alternatively, each permanent magnet 52 comprises a single fixing pin 52 or a number of fixing pins greater than 2.

[0048] According to a variant, fixing pins 52 are fixed between all the permanent magnets of the first row 30 and of the second row 44.

[0049] According to another variant, only certain permanent magnets of the first row 30 and of the second row 44 comprise fixing pins, for example one permanent magnet out of two.

[0050] According to a variant not shown, the third lateral faces 40 and the fourth lateral faces 42 of the permanent magnets of the first row and / or of the permanent magnets of the second row further comprise at least one hole 50 and at least a fixing pin 52 so as to reinforce the holding of the permanent magnets in an axial direction XX.

[0051] According to a second embodiment illustrated in [Fig.4], the rotor assembly 6 comprises a crown 54 which is identical to the crown 8 according to the first embodiment except for the fact that the permanent magnets 28 do not comprise holes and fixing pins.

[0052] According to a third embodiment illustrated in [Fig. 5], the rotor assembly 6 comprises the ring 56 which comprises permanent magnets 58 aligned along a single row, hereinafter called the first row. In this embodiment, the permanent magnets 58 are identical to the permanent magnets 28 of the first embodiment. They will not be described a second time. In the embodiment illustrated in [Fig. 5] as an example, the permanent magnets 58 have a width 1 greater than the width of the permanent magnets 28 of the first and second embodiments.

[0053] In this embodiment, the first lateral face 36 of the permanent magnets 58 is fixed in the vicinity of the first lateral edge 24 of the crown and the second lateral face 38 of the permanent magnets 58 is fixed in the vicinity of the second lateral edge 26 of the crown.

[0054] In this embodiment, the second main face 34 and / or the second lateral face 38 of the permanent magnets 58 of the row comprises an additional cavity 60.

[0055] In the embodiment illustrated in [Fig. 5], the additional cavity 60 opens both onto the space opposite the first lateral face 36 and onto the space opposite the second main face 34. The additional cavity 60 is arranged in the vicinity of the second lateral edge 26 of the crown.

[0056] According to a variant, the additional cavity 60 is formed by a groove opening only onto the first lateral face 36.

[0057] According to another variant, the additional cavity 60 is formed by a groove opening only onto the second main face 34.

[0058] The crown 56 further comprises an additional ring 62 housed in the additional cavities 60 of the permanent magnets of the first row. The additional ring 62 surrounds the permanent magnets of the first row.

[0059] The additional ring 62 is for example made of non-magnetic stainless steel or a composite material.

[0060] The present invention is applicable to any rotating electrical machine comprising a crown provided with permanent magnets, such as for example an alternator, an electric motor or a starter.

Claims

Claims

1. Rotating electrical machine (2) comprising a stator assembly (4), and a rotor assembly (6) pivotally mounted relative to the stator assembly about an axis of rotation (X), the rotor assembly (6) comprising a ring (8, 54, 56) comprising: - at least one first lateral edge (24), - a plurality of permanent magnets (28, 58) fixed along the first lateral edge (24) of the ring, the plurality of permanent magnets being aligned so as to form a first row (30); the permanent magnets of the first row comprising a first main face (32) fixed to the ring, a second main face (34) opposite the first main face and a first lateral face (36) arranged in the vicinity of the first lateral edge (24); - at least one first ring (43) surrounding the permanent magnets of the first row;characterized in that the second main face (34) and / or the first lateral face (36) of the permanent magnets of the first row comprises at least one cavity (41), and in which said at least one first ring (43) is housed in said cavity.;

2. Rotating electrical machine (2) according to claim 1, wherein said at least one cavity (41) opens onto the second main face (34) and onto the first lateral face (36) of the permanent magnets of the first row.

3. Rotating electrical machine (2) according to claim 1, wherein the crown (8, 54) comprises: - a second lateral edge (26) opposite the first lateral edge, - a plurality of permanent magnets (28) fixed along the second lateral edge, the plurality of permanent magnets being aligned and forming a second row (44), the permanent magnets of the second row (44) comprising a first main face (32) fixed to the crown, a second main face (34) opposite the first main face and a first lateral face (38) arranged in the vicinity of the second lateral edge (26), the second main face (34) and / or the first lateral face (36) of the permanent magnets of the second row (44) comprises a cavity (46); - at least one second ring (48) housed in said cavity (46) of the permanent magnets of the second row; said at least one second ring (48) surrounding the permanent magnets of the second row.

4. Rotating electrical machine (2) according to claim 3, wherein said cavity (46) opens onto the second main face (34) and onto the first lateral face (36) of the permanent magnets of the second row.

5. Rotating electrical machine (2) according to any one of claims 3 and 4, wherein the permanent magnets of the first row (30) and of the second row (44) comprise a second lateral face (38) opposite the first lateral face (36); the second lateral faces (38) of at least a portion of the permanent magnets of the first row (30) and of the second row (44) comprise at least one hole (50), and wherein said crown (8) comprises fixing pins (52) fixed, on the one hand, in the holes (50) of the permanent magnets of the first row (30) and, on the other hand, in the holes (50) of the permanent magnets of the second row (44).

6. Rotating electrical machine (2) according to any one of claims 1 to 5, in which the cavities (41) of the permanent magnets of the first row have a depth (P) of between 3 and 6 millimeters.

7. Rotating electrical machine (2) according to any one of claims 1 to 4, in which the cavities (41) have a width (L) of between 1.5 and 4 millimeters.

8. A rotating electrical machine (2) according to any one of claims 1 to 7, wherein the first ring (43) is made of a non-magnetic stainless steel or a composite material.

9. A rotating electrical machine (2) according to any one of claims 3 to 8, wherein the second ring (48) is made of a non-magnetic stainless steel or a composite material.

10. Rotating electrical machine (2) according to any one of claims 1 and 2, wherein the permanent magnets (58) of the first row comprise a second lateral face (38) opposite the first lateral face, the second main face (34) and / or the second lateral face (38) of the permanent magnets of the first row comprising an additional cavity (60); and wherein said crown (56) further comprises an additional ring (60) housed in the additional cavities (60) of the magnets

11. permanent magnets of the first row; the additional ring (62) surrounding the permanent magnets of the first row. Rotating electrical machine (2) according to claim 10, in which the additional ring (62) is made of a non-magnetic stainless steel or a composite material.

Images