ROTOR OF A PERIODIC ELECTRIC MACHINE AND ELECTRIC PERIODIC MACHINE EQUIPPED WITH SUCH A ROTOR

Description

[0001] The invention relates to a rotor of a rotating electrical machine comprising permanent magnets fixed using a resin. The invention also relates to a rotating electrical machine equipped with such a rotor.

[0002] Known from Japanese patent application JP2014222964A2 is a rotor for a rotating electrical machine, capable of interacting with a stator of the rotating electrical machine and rotating relative to an axis of rotation, the rotor comprising: a rotor body comprising first cavities extending from a first end of the rotor body to a second end of the rotor body in the direction of the axis of rotation, permanent magnets housed in the first cavities, a fixing space being formed between at least a first face of at least one of the permanent magnets and a second face of the first cavity in which it is housed, a resin inserted into the fixing space,

[0003] In this type of rotor, the various rotor components are only fixed together by the use of permanent magnet fixing resin. Such fixing may be insufficient and relative movement between the components, particularly the laminations of a stack of magnetic laminations of the rotor, may occur during operation of the rotating electrical machine. Such movement can cause wear, noise and damage to the electrical machine. In addition, since the rotor does not include a flange at these ends, balancing it is difficult. Machining of the laminations of the stack of laminations may be necessary. This machining can lead to a degradation of the performance of the rotating electrical machine.

[0004] Known from American patent application US2017 / 0085160A1 is a rotor for a rotating electrical machine, capable of interacting with a stator of the rotating electrical machine and rotating relative to an axis of rotation, the rotor comprising: a rotor body comprising: first cavities extending from a first end of the rotor body to a second end of the rotor body in the direction of the axis of rotation, third cavities extending from a first end of the rotor body to a second end of the rotor body in the direction of the axis of rotation and having an axis parallel to the axis of rotation, permanent magnets housed in the first cavities, a first holding assembly bearing on the first end of the rotor body and comprising holes, a second holding assembly bearing on the second end of the rotor body, tie rods, passing through the second cavities and through the holes of the first holding assembly, making it possible to clamp the rotor body between the first holding assembly and the second holding assembly.

[0005] In this type of rotor, the permanent magnets are not fixed in the first cavities. They can, in particular, have a movement in a radial and circumferential direction. Indeed, the first holding assembly and the second holding assembly can only limit the movements of the permanent magnets in the direction of the axis of rotation. This possibility of movement of the permanent magnets leads to difficulties in balancing the rotor and a risk of noise during operation of the rotating electrical machine.

[0006] US patent application US20080238219A1 discloses a rotor comprising: a rotor body comprising first cavities receiving magnets, a fixing space being formed between the magnets and a face of the first cavity, and third cavities, a first and a second holding assemblies clamping the rotor body between them by means of tie rods passing through the third cavities, a resin being inserted into the fixing space through a feed passage.

[0007] The present invention aims to solve all or part of these drawbacks. The invention relates to a rotor for a rotating electrical machine, capable of interacting with a stator of the rotating electrical machine and rotating relative to an axis of rotation, the rotor comprising: a rotor body comprising: first cavities extending from a first end of the rotor body to a second end of the rotor body in the direction of the axis of rotation, third cavities extending from a first end of the rotor body to a second end of the rotor body in the direction of the axis of rotation and having an axis parallel to the axis of rotation, permanent magnets housed in the first cavities, a fixing space being formed between at least a first face of at least one of the permanent magnets and a second face of one of the first cavities in which the at least one permanent magnet is housed, a first holding assembly bearing on the first end of the rotor body and comprising second holes, a second holding assembly bearing on the second end of the rotor body, tie rods, passing through the third cavities and through the second holes of the first holding assembly,allowing the rotor body to be clamped between the first holding assembly and the second holding assembly, a resin inserted into the fixing space, , wherein the first holding assembly comprises a feed passage communicating with the attachment space, the feed passage being adapted to receive a resin feed device.

[0008] Such a type of rotor allows the permanent magnets to be held securely in their cavity by using resin while ensuring the cohesion of the rotor. According to the invention, the first holding assembly comprises a counterbore having a bottom, the bottom comprising the feed passage and a flat bearing surface on which the tie rod rests, the feed passage and the bearing surface having a common edge. The use of such a feed passage having a common edge with the bearing surface on which the tie rod rests makes it possible to reduce the size of the feed passage. Indeed, thanks to this characteristic, there is no material of the first holding assembly between a part of the tie rod resting on the flat bearing surface and the feed passage in a plane perpendicular to the axis of rotation. It is thus possible to increase the size of the areas outside the counterbore and feed passage of the first holding assembly.These areas can then be thicker. They can then be used to balance by removing material from the rotor and thus reduce vibrations during operation of the rotating electrical machine.

[0009] According to an additional characteristic of the invention, the second holding assembly comprises third holes through which the tie rods pass.

[0010] According to an additional characteristic of the invention, the supply passage being inscribed between a first plane and a second plane forming an angular sector, the first plane and the second plane passing through the axis of rotation, one of the second holes is located in the angular sector.

[0011] This arrangement allows for thicker areas angularly between the tie rods and the feed passages. These thicker areas increase the rigidity of the first retaining assembly. These thicker areas can also be used for balancing by removing material from the rotor.

[0012] According to an additional characteristic of the invention, the supply passage being inscribed between a first plane and a second plane forming an angular sector, the first plane and the second plane passing through the axis of rotation, one of the second holes having an axis, the axis is located in the angular sector.

[0013] This arrangement also allows for thicker areas angularly between the tie rods and the feed passages. These thicker areas increase the rigidity of the first retaining assembly. These thicker areas can also be used for balancing by removing material from the rotor.

[0014] According to an additional characteristic of the invention, the supply passage communicates with several fixing spaces, in particular two.

[0015] The use of such a feed passage allows the use of a wider passage and therefore facilitates the flow of the resin during its insertion. Indeed, it is thus possible to eliminate separations between the feed passages and therefore to have larger feed passages without increasing the overall size of the feed passages in the first holding assembly.

[0016] According to an additional characteristic of the invention, the first holding assembly comprises a vent communicating with the fixing space and capable of allowing the evacuation of a gas during the insertion of the resin, the supply passage and the vent being distinct.

[0017] The use of such a vent makes it easier to fill the resin in the fixing space by facilitating the evacuation of gas, particularly atmospheric air, occupying the fixing space before the resin is inserted. Bubble formation in the resin is also reduced. This improves the fixing of the permanent magnets. With the permanent magnets securely fixed, balancing the rotor is easier.

[0018] According to an additional characteristic of the invention, the tie rods comprise a fixing element, the fixing element bearing on the bearing surface.

[0019] According to an additional characteristic of the invention, the tie rod is a screw and the fixing element is a head of the screw, the head of the screw bearing on the bearing surface.

[0020] According to an additional characteristic of the invention, the tie rod comprises a screw and the fixing element is a nut, the nut bearing on the bearing surface.

[0021] The invention also relates to a rotating electrical machine comprising a rotor as described above and a stator.

[0022] In all of the above, the rotor may comprise any number of pole pairs, for example six or eight pole pairs.

[0023] In all of the above, the rotating electrical machine may have a stator having a polyphase electrical winding, for example formed by wires or by conductive bars connected to each other.

[0024] The rotating electrical machine may comprise a power electronic component, capable of being connected to the on-board network of a vehicle. This power electronic component comprises, for example, an inverter / rectifier allowing, depending on whether the rotating electrical machine operates as a motor or a generator, to charge an on-board network of the vehicle or to be electrically powered from this network.

[0025] The rotating electrical machine may also comprise a pulley or any other means of connection to the rest of a powertrain of the vehicle. The rotating electrical machine is for example connected, in particular via a belt, to the crankshaft of a thermal engine of the vehicle. Alternatively, the rotating electrical machine is connected to other locations of the powertrain, for example to the input of a gearbox from the point of view of the torque transmitted to the wheels of the vehicle, to the output of the gearbox from the point of view of the torque transmitted to the wheels of the vehicle, at the gearbox from the point of view of the torque transmitted to the wheels of the vehicle, or even on the front axle or the rear axle of this powertrain.

[0026] The invention may be better understood by reading the following description of non-limiting examples of its implementation and by examining the attached drawing in which: there figure 1 represents a partial schematic sectional view of a rotating electrical machine, the figure 2 represents a schematic view of a rotor of a rotating electrical machine according to a first embodiment of the invention, the figure 3 represents a partial schematic view of the rotor of the figure 2 , there figure 4 represents a detail of the view of the figure 3 , there figure 5 represents a schematic view of a first rotor holding assembly of the figure 2 , there figure 6 represents a schematic view of a second rotor holding assembly of the figure 2 , there figure 7 represents a detail of a view along a plane perpendicular to an axis of rotation of the rotor of the figure 2 , there figure 8 represents a partial sectional view of the rotor of the figure 2 , there figure 9 represents a partial sectional view of a rotor according to a second embodiment, the figure 10 represents another schematic view of the first assembly of the maintenance of the figure 5 , there figure 11 represents a detail of the first set of maintenance of the figure 5 .

[0027] In all the figures, identical elements or elements performing the same function have the same reference numbers. The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment or that the features apply only to a single embodiment. Single features of different embodiments may also be combined or interchanged to provide other embodiments.

[0028] There figure 1 represents a partial schematic sectional view of a rotating electrical machine 1 having an axis of rotation A. The rotating electrical machine 1 comprises a stator 2 and a rotor 3 in a casing. The rotor 3 is capable of interacting with the stator 2. The casing comprises, for example, a first bearing 5, a second bearing 6 and a tubular spacer 7. The tubular spacer 7 is, for example, clamped between the first bearing 5 and the second bearing 6, for example by means of tie rods not shown between the first bearing 5 and the second bearing 6. The stator is fixed inside the casing, for example mounted tightly in the tubular spacer 7.

[0029] For the purposes of the invention, unless otherwise specified, the terms radial and radially are understood to mean in relation to the axis of rotation A. For the purposes of the invention, unless otherwise specified, the terms longitudinal and longitudinally mean in the direction of the axis of rotation A.

[0030] In a non-shown embodiment of the invention, the tubular spacer comprises a cooling chamber in which a cooling liquid circulates.

[0031] In a non-shown embodiment of the invention, there is no tubular spacer and the stator is sandwiched between the first bearing and the second bearing.

[0032] The stator comprises a stator body 9 and a winding 8. The stator body 9 comprises, for example, a first stack of magnetic laminations. For example, the winding 8 comprises electrical conductors, an active part of which passes through notches formed in the stator body 9 and a connection part or bun is formed outside the notches. The winding 8 is, for example, a hairpin-type winding.

[0033] The rotor 3 is for example fixed on a shaft 4 with an axis of rotation A. The shaft 4 is guided in rotation by a first bearing 11 mounted in the first bearing 5 and a second bearing 12 mounted in the second bearing 6. A drive element 13, for example a pulley or a gear, is fixed to the shaft 4.

[0034] In another embodiment not shown, the shaft 4 is guided in rotation relative to the first bearing and the second bearing by means of other known rotational guide means, for example plain bearings.

[0035] There figure 2 represents the rotor 3 according to a first embodiment and the shaft 4. The rotor 3 comprises a rotor body 16. The rotor body 16 extends longitudinally from a first end 24 of the rotor body 16 to a second end 25 of the rotor body 16.

[0036] The rotor 3 further comprises a first holding assembly 15 bearing on the first end 24 of the rotor body 16. The rotor 3 also comprises a second holding assembly 14 bearing on the second end 25 of the rotor body 16. The rotor body 16 is then clamped between the first holding assembly 15 and the second holding assembly 14.

[0037] There figure 3 is a partial view of rotor 3 and shaft 4. On the figure 3 , the first holding assembly 15 is not shown to allow a more detailed view of the other components of the rotor 3.

[0038] First cavities 23, for example longitudinal, are formed in the rotor body 16. The rotor body 16 comprises for example a second stack of magnetic sheets. The rotor 3 further comprises permanent magnets 26, for example longitudinal, housed in the first cavities 23.

[0039] In the embodiments of the invention shown in the figures, the permanent magnets 26 comprise a plurality of elementary permanent magnets.

[0040] In another embodiment of the invention not shown, the permanent magnets comprise a single elementary permanent magnet.

[0041] A fixing space 29 is formed between at least a first face 28 of at least one of the permanent magnets 26 and a second face 27 of one of the first cavities 23 in which the at least one permanent magnet 26 is housed. A resin 64 is inserted into the fixing space. The resin is not shown in the figures 1 à 10 to improve the readability of these figures. The resin 64 participates in the fixing of the permanent magnets 26 in the first cavities 23 of the rotor body 16.

[0042] In the embodiments of the invention shown in the figures, the rotor 3 comprises magnetic poles formed by two permanent magnets forming a V shape in a plane orthogonal to the axis of rotation.

[0043] In another embodiment of the invention not shown, the magnetic poles of the rotor are formed by three permanent magnets forming a U shape in a plane orthogonal to the axis of rotation.

[0044] In another embodiment of the invention not shown, the magnetic poles of the rotor are formed by a U-shaped magnet in a plane orthogonal to the axis of rotation.

[0045] In another embodiment of the invention not shown, the magnetic poles of the rotor are formed by radially magnetized magnets.

[0046] There figure 4 represents a detail of the figure 3 on which the fixing space 29 is visible.

[0047] The fixing space 29 may comprise a first housing 38 and a second housing 39.

[0048] There figure 5 represents the first holding assembly 15 of the rotor 3. The first holding assembly 15 comprises a supply passage 18 communicating with the fixing space 29. The supply passage 18 is adapted to receive a resin supply device. The resin supply device comprises for example a hollow needle penetrating into the supply passage 18 during insertion of the resin 64. The resin 64 is for example inserted in liquid form and then polymerized using a heating device.

[0049] The first holding assembly may further comprise a vent 32 communicating with the fixing space 29. The vent 32 allows the evacuation of a gas, in particular atmospheric air, during the insertion of the resin 64. The supply passage 18 and the vent 32 are for example distinct.

[0050] The feed passage 18 may communicate with several attachment spaces 29. For example, in the embodiments shown in the figures, the feed passage 18 communicates with two attachment spaces 29.

[0051] The vent 32 may comprise a first passage 34 formed in the first holding assembly 15. The first passage 34 comprises, for example, a first groove 37 formed in the first holding assembly 15. The first groove 37 is, for example, machined in the first holding assembly 15.

[0052] The first passage 34 comprises a first end 30 which opens for example into the fixing space 29.

[0053] The rotor body 16 may comprise a second cavity 35, for example a longitudinal cavity located radially inside the first cavities 23. The first passage 34 may comprise a second end 31 opening into the second cavity 35.

[0054] The vent 32 may further comprise a first hole 36 passing through the first holding assembly 15. The first hole 36 may open into the second cavity 35.

[0055] In another embodiment of the invention not shown, the vent also comprises a first hole and the second end of the first passage opens directly into the first hole.

[0056] In another embodiment of the invention not shown, a first space, for example annular, is formed between the shaft and the first holding assembly. The second end of the first passage opens into the first space.

[0057] The vent 32 can communicate with several fixing spaces 29. In the embodiments of the invention shown in the figures, the vent 32 communicates with two fixing spaces 29. For example, the first passage 34 comprises a first portion 51 of circumferential orientation relative to the axis of rotation A and a second portion 52 for connection with the second cavity 35. The first portion 51 connects, for example, two fixing spaces 29. The first portion 51 and the second portion 52 are connected to each other.

[0058] The fixing space 29 may comprise a first housing 38 and a second housing 39. The first housing 38 and second housing 39 are for example formed opposite two first opposite faces 28 of a permanent magnet 26. The supply passage 18 may communicate with the first housing 38 and the vent 32 may communicate with the second housing 39.

[0059] There figure 6 represents the second holding assembly 14 of the rotor 3 according to the first embodiment of the invention. The second holding assembly 14 may comprise a second passage 40 connecting the first housing 38 to the second housing 39.

[0060] In the first embodiment of the invention, the second passage 40 may comprise a second groove 41 formed in the second holding assembly 14. The second groove is for example machined in the second holding assembly 14.

[0061] The second passage 40 can also connect several fixing spaces 29. For example, in the embodiments of the invention shown in the figures, the second passage 40 connects two fixing spaces 29. The second passage 40 comprises for example a third portion 53 connecting the first housing 38 to the second housing 39 as well as a fourth portion 54 connecting two third portions.

[0062] There figure 7 represents a detailed view of rotor 3.

[0063] The rotor body comprises third cavities 21. The third cavities 21 extend from the first end 24 of the rotor body 16 to the second end 25 of the rotor body 16 in the direction of the axis of rotation A. The third cavities 21 have an axis parallel to the axis of rotation A. The third cavities 21 extend for example between a first radius 42 and a second radius 43, the first radius 42 being smaller than the second radius 43.

[0064] The rotor comprises tie rods 17 passing through the third cavities 21 and through second holes 20 of the first holding assembly 15. The tie rods 17 make it possible to clamp the rotor body 16 between the first holding assembly 15 and the second holding assembly 14.

[0065] There figure 10 represents a view of the first holding assembly. The first holding assembly may comprise a counterbore 60 having a bottom. The bottom may comprise a flat bearing surface 55 on which the tie rod 17 bears. The supply passage 18 and the bearing surface 55 may have an edge 56 in common.

[0066] The feed passage 18 and the counterbore 60 may form a funnel or a bowl for the insertion of the resin 64.

[0067] There figure 11 shows a detail of the first holding assembly and in particular the counterbore 60 as well as the feed passage 18. Resin 64 has been inserted into the feed passage. The feed passage 18 can be used as a resin reservoir 64 when inserting the resin 64.

[0068] As shown in the figure 7 , the supply passage 18 is inscribed between a first plane 57 and a second plane 58 forming an angular sector 59, the first plane 57 and the second plane 58 passing through the axis of rotation A. One of the second holes 20 is for example located in the angular sector 59.

[0069] One of the second holes 20 may have an axis 60. The axis 60 is located in the angular sector 59.

[0070] Each of the feed passages may be inscribed in an angular sector 59. The areas located between the angular sectors 59 of the first holding assembly may for example be machined to balance the rotor 3.

[0071] The tie rods can also pass through third holes 22 of the second holding assembly 14.

[0072] The tie rods comprise, for example, a fixing element 61, in particular a fixing element 61 bearing on the bearing surface 55.

[0073] In a non-shown embodiment of the invention, the tie rod 17 may be a screw and the fixing element is a head of the screw. The head of the screw is, for example, supported on the support surface 55. The screw may comprise a threaded rod. The rod of the screw is, for example, screwed into the second holding assembly, the second holding assembly comprising a third threaded hole or, for example, an overmolded nut to receive the threaded rod.

[0074] In the embodiments shown in the figures, the tie rod 17 comprises a screw 63 and the fixing element is a nut 62. The nut 62 bears on the bearing surface 55. The nut 62 is for example a flange nut. In another embodiment of the invention, not shown, the nut 62 bears on the bearing surface 55 by means of a washer. The screw 63 may comprise a head. The head bears, for example, on the second holding assembly. In another embodiment of the invention, not shown, the head of the screw is overmolded in the second holding assembly.

[0075] The first hole 36 and the supply passage 18 are for example each located radially inside the first radius 42 or outside the second radius 43.

[0076] There figure 8 represents a partial section in secant planes of the rotor 3 according to the first embodiment of the invention. The section is made along a line 33 shown on the figure 7 .

[0077] This section shows a path 44 followed by the resin 64 and the gas during the insertion of the resin 64 into the fixing space 29.

[0078] There figure 9 represents a partial section in secant planes of the rotor 3 according to the second embodiment of the invention. The section is, like that of the figure 8 , made according to a line 33 shown on the figure 7 .

[0079] The second embodiment of the invention is similar to the first embodiment of the invention. However, the embodiment of the first holding assembly 15 and the second holding assembly 14 is different.

[0080] In the second embodiment of the invention, the first holding assembly 15 may comprise a first end portion 45 and a first intermediate portion 46 of flat shape. The first intermediate portion 46 is for example made of sheet metal. The first intermediate portion 46 is for example clamped between the first end portion 45 and the rotor body 16. The first passage comprises a first opening 47 passing through a thickness of the first intermediate portion 46. The first opening 47 is for example made by cutting.

[0081] Likewise, the second holding assembly 14 may comprise a second end portion 48 and a second intermediate portion 49 of flat shape. The second intermediate portion 49 is for example made of sheet metal. The second intermediate portion 49 is for example clamped between the second end portion 25 and the rotor body 16. The second passage 40 comprises a second opening 50 passing through a thickness of the second intermediate portion 49. The second opening 50 is made by cutting.

[0082] In another embodiment of the invention not shown, the first holding assembly is as described for the first embodiment of the invention and the second holding assembly is as described for the second embodiment of the invention.

[0083] In another embodiment of the invention not shown, the first holding assembly is as described for the second embodiment of the invention and the second holding assembly is as described for the first embodiment of the invention.

[0084] In another embodiment of the invention, not shown, the first holding assembly does not include a vent. The gas can then be evacuated by the natural rise of the gas to the surface of the resin, in particular in the form of bubbles.

[0085] In another embodiment of the invention, not shown, the second holding assembly does not include a second passage. The gas can then be evacuated by natural rise of the gas to the surface of the resin or by means of a free space provided between the permanent magnet and the second holding assembly.

Claims

1. Rotor (3) for a rotary electric machine (1), able to interact with a stator (2) of the rotary electric machine (1) and rotating with respect to an axis of rotation (A), the rotor (3) comprising: - a rotor body (16) comprising: - first cavities (23) extending from a first end (24) of the rotor body (16) to a second end (25) of the rotor body (16) in the direction of the axis of rotation (A), - third cavities (21) extending from the first end (24) of the rotor body (16) to the second end (25) of the rotor body (16) in the direction of the axis of rotation (A) and having an axis parallel to the axis of rotation (A), - permanent magnets (26) housed in the first cavities (23), a fixing space (29) being formed between at least a first face (28) of at least one of the permanent magnets (26) and a second face (27) of one of the first cavities (23) in which the at least one permanent magnet (26) is housed, - a first retaining assembly (15) bearing against the first end (24) of the rotor body (16), and comprising second holes (20), - a second retaining assembly (14) bearing against the second end (25) of the rotor body (16), - tie rods (17), passing through the third cavities (21) and through the second holes (20) in the first retaining assembly (15), so that the rotor body (16) can be clamped between the first retaining assembly (15) and the second retaining assembly (14), - a resin (64) introduced into the fixing space (29), wherein the first retaining assembly (15) comprises a supply passage (18) communicating with the fixing space (29), the supply passage (18) being able to receive a resin supply device, characterized in that the first retaining assembly (15) comprises a counterbore (60) having a bottom, the bottom comprising the supply passage (18) and a planar bearing surface (55) on which the tie rod (17) bears, the supply passage (18) and the bearing surface (55) having an edge (56) in common so as to leave no material of the first retaining assembly (15) between a portion of the tie rod (17) resting on the planar bearing surface and the supply passage (18).

2. Rotor (3) according to one of the preceding claims, wherein the second retaining assembly (14) comprises third holes (22) through which the tie rods (17) pass.

3. Rotor (3) according to one of the preceding claims, wherein, with the supply passage (18) being inscribed between a first plane (57) and a second plane (58) forming an angular sector (59), the first plane (57) and the second plane (58) passing through the axis of rotation (A), one of the second holes (20) is located in the angular sector (59).

4. Rotor (3) according to one of Claims 1 to 2, wherein, with the supply passage (18) being inscribed between a first plane (57) and a second plane (58) forming an angular sector (59), the first plane (57) and the second plane (58) passing through the axis of rotation (A), one of the second holes (20) having an axis (60), the axis (60) is located in the angular sector (59).

5. Rotor (3) according to one of the preceding claims, wherein the supply passage (18) communicates with several fixing spaces (29), notably with two.

6. Rotor (3) according to one of the preceding claims wherein the first retaining assembly (15) comprises a vent (32) communicating with the fixing space (29) and designed to permit the venting of gas upon insertion of the resin (64), the supply passage (18) and the vent (32) being separate.

7. Rotor (3) according to one of the preceding claims, wherein the tie rods comprise a fixing element (61), the fixing element bearing on the bearing surface (55).

8. Rotor (3) according to the preceding claim, wherein the tie rod (17) is a screw and the fixing element is a head of the screw, the head of the screw bearing on the bearing surface (55).

9. Rotor (3) according to Claim 7 wherein the tie rod (17) comprises a screw (63) and the fixing element is a nut (62), the nut (62) bearing against the bearing surface (55).

10. Rotary electric machine (1) comprising a rotor (3) according to one of the preceding claims and a stator (2).