Rotor end shield for an electric machine
Patent Information
- Application Number
- EP2023810424
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-17
- Filing Date
- 2023-10-13
- Publication Date
- 2025-08-27
AI Technical Summary
Existing cooling methods for rotating electrical machines, particularly those cooled by air circulation, are inadequate in effectively managing high temperature zones near the stator coil heads and rotor, leading to suboptimal cooling efficiency.
A rotor flange design featuring circumferentially distributed cavities and radially extending curved fins on its exterior face, with optional radial openings and varying circumferential borders, enhances air mixing and flow directionality to improve cooling efficiency.
The design significantly enhances cooling efficiency by accelerating air flow and improving heat dissipation, even at high rotation speeds, thereby extending the lifespan and performance of electrical machines.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] Title: Rotor flange of an electric machine
[0003] Technical field
[0004] The present invention relates to rotating electrical machines, and more particularly to those cooled by a circulation of a cooling fluid, in particular air, circulating at least partially around the rotor of the machine.
[0005] The invention relates more particularly to synchronous or asynchronous alternating current machines. It relates in particular to traction or propulsion machines for electric (Battery Electric Vehicle) and / or hybrid (Hybrid Electric Vehicle - Plug-in Hybrid Electric Vehicle) motor vehicles, such as private cars, vans, trucks or buses. The invention also applies to rotating electrical machines for industrial and / or energy production applications, in particular naval, aeronautical or wind power applications.
[0006] Prior art
[0007] It is known to cool rotating electrical machines, in particular the stator coil heads, during operation of the rotating electrical machine by a fluid, in particular by a gas, in particular by air circulating in the electrical machine.
[0008] Such electrical machines often have high temperature zones located near the stator coil heads and in the rotor of the electrical machine. Since the coil heads are in contact with the cooling fluid, the quality of their cooling depends on the internal forced convection of the cooling fluid in the electrical machine.
[0009] Applications JP 2020 120486 and EP 3 934 065 disclose flanges not having cavities distributed circumferentially around the central bore of the flange.
[0010] Application WO 2021 / 115806 relates to a flange comprising rectilinear fins on its outer face, i.e. the face which is not turned towards the rotor mass.
[0011] Application CN 211266684 discloses a flange comprising rectilinear fins. Applications KR 10-2018-0094446, CN 207459903 and EP 3 672 035 disclose flanges not comprising cavities delimited at least by a circumferential edge extending along the edge of the flange.
[0012] Application US 2021 / 0242746 discloses a flange not having fins on its outer face, i.e. the face which is not turned towards the rotor mass.
[0013] There is a need to further improve the cooling of rotating electrical machines cooled by circulating cooling fluid, particularly air.
[0014] Statement of the invention
[0015] The invention aims to meet this need and achieves this, according to one of its aspects, by means of a rotor flange of an electrical machine rotating around an axis of rotation X, the flange comprising an inner face facing a rotor mass of the rotor, an outer face opposite the inner face, a radially outer edge extending between the inner face and the outer face, and a central bore, the flange comprising:
[0016] - at least two cavities provided on the outer face of the flange and distributed circumferentially around the central bore, each cavity being delimited at least by a circumferential edge extending along the edge of the flange, and
[0017] - at least one fin separating two consecutive cavities, the fin extending substantially radially and being curved when the flange is observed along the axis of rotation X.
[0018] Each cavity may be delimited at least partially by two fins and a circumferential border.
[0019] The thickness of the flange, measured in the axial direction, between the inner and outer faces, can be between 5 and 30 mm, better still between 7 and 20 mm, even better still between 10 and 15 mm, being for example of the order of 9 mm or 13 mm.
[0020] The depth of a cavity, measured in the axial direction, can be between 3 and 24 mm, better between 4 and 20 mm, even better between 5 and 15 mm, being for example of the order of 6.6 mm. Such a depth allows good mixing of the cooling fluid, which improves the cooling of the rotor. The depth of a cavity can increase when moving away from the axis of rotation X, in order to guide the air to the level of the winding heads. The depth of a cavity can thus be greater at the level of the edge of the flange.
[0021] A ratio between the depth of a cavity and the thickness of the flange can be between 5 and 95%, better between 10 and 90%, better between 20 and 85%, better between 30 and 80%, being for example of the order of 50% or 75%.
[0022] The outer diameter of the flange can be between 50 and 300 mm, better between 75 and 200 mm, even better between 100 and 150 mm, being for example of the order of 100 mm or 136 mm.
[0023] The width of a circumferential border, measured in the radial direction, may be between 3 and 30 mm, better between 4 and 20 mm, better between 5 and 15 mm, being for example of the order of 6 mm or 10 mm or 12 mm.
[0024] The ratio between the width of a circumferential edge and the external diameter of the flange can be between 1 and 25%, better between 2 and 20%, better between 3 and 15%, better between 4 and 10%, being for example of the order of 4.5% or 6%.
[0025] The circumferential edge may connect the radial ends closest to the edge of the flange of two consecutive fins. The circumferential edge may connect the radial ends closest to the edge of the flange of two consecutive fins surrounding a cavity, such that said cavity is delimited over its entire periphery by the two fins and by the circumferential edge.
[0026] When viewed in section along a plane perpendicular to a radial axis extending between two consecutive cavities, a line connecting an edge of a fin and the portion of a cavity closest to the inner face may not include a portion of plane contained in a plane perpendicular to the axis of rotation. In other words, there may be no flat area between the adjacent fin and cavity. The fin may be arranged at the edge of the cavity.
[0027] In a particular embodiment, the flange may be devoid of an axially through opening other than the central bore.
[0028] In particular, at least one cavity, in particular half of the cavities, better all the cavities may be devoid of through openings. The cavities may have a solid bottom, devoid of axially through openings. Alternatively, the flange may comprise one or more axially through openings. The axially through opening(s) may for example be located in the bottom of each cavity.
[0029] These axially passing through openings may be located opposite housings intended to receive permanent magnets of the rotor mass. The shape of the passing through openings may be substantially the same as that of the housings of the permanent magnets of the rotor mass when the rotor is observed along its axis of rotation X.
[0030] These through openings allow air to flow axially through the rotor. Preferably, the rotor has two flanges, each located at one end of the rotor mass, and each flange has through openings to exhaust air from the rotor.
[0031] Cavity
[0032] At least one cavity, in particular half of the cavities, better all of the cavities, may have a circumferential border comprising a radial opening made in the edge of the flange.
[0033] Such a radial opening thus provides a radial outlet for the air contained in the cavity. The air can thus be directed out of the end plate towards the areas of the electric machine which are to be cooled, for example the coil heads of the stator of the electric machine.
[0034] A length of the radial opening measured in a circumferential direction may be between 1 and 50 mm, better between 2 and 40 mm, better between 3 and 30 mm, better between 4 and 20 mm, even better between 5 and 10 mm, being for example of the order of 7.3 mm.
[0035] A length of the cavity into which the radial opening opens, measured in a circumferential direction, may be between 5 and 500 mm, better still between 10 and 200 mm, even better still between 15 and 100 mm, even better still between 20 and 80 mm, even better still between 30 mm and 60 mm, being for example of the order of 37 mm.
[0036] The ratio between the length of the radial opening measured in a circumferential direction and the length of the cavity into which the radial opening opens measured in a circumferential direction may be between 2 and 30, better between 3 and 20, better between 4 and 10, for example of the order of 5. The fact that the circumferential length of the radial opening is much less than the circumferential length of the cavity allows the formation of a bottleneck at the radial opening. The speed of the air exiting through this radial opening is thus accelerated, which improves the cooling of the machine.
[0037] In addition, the reduced size of the radial opening(s) provided on the edge of the flange allows sufficient material to be left to simply balance the flange by removing material.
[0038] The depth of the radial opening may be less than the thickness of the circumferential rim.
[0039] The portion of the radial opening closest to the inner face of the flange may be curved when viewed in a radial direction. Alternatively, the portion of the radial opening closest to the inner face of the flange may be straight when viewed in a radial direction.
[0040] A radial opening with a portion closest to the inner face of the curved flange improves resistance to centrifugal force. The material constituting the flange is thus less stressed at high speeds and the cooling of the machine is thus improved.
[0041] The radial opening may have parallel side edges when the edge of the flange is viewed in a radial direction. Alternatively, the radial opening may have flared edges when the edge of the flange is viewed in a radial direction. In particular, the edges of the radial opening may flare towards the outer face of the flange. Such a flared radial opening allows a wider airflow to be ejected towards the coil heads.
[0042] The lateral edges of the radial opening may be parallel to a plane containing the axis of rotation X and passing through the radial end of the fin closest to the edge when observing the flange along the axis of rotation X.
[0043] Alternatively, the lateral edges of the radial opening may be inclined relative to a plane containing the axis of rotation X and passing through the radial end of the fin closest to the edge when observing the flange along the axis of rotation X.
[0044] Preferably, the two lateral edges of the same radial opening may be parallel to each other. Alternatively, the two lateral edges of the same radial opening may not be parallel to each other. In particular, the two lateral edges of the same radial opening may have different inclinations relative to a plane containing the axis of rotation X and passing through the radial end of the fin closest to the edge when the flange is observed along the axis of rotation X.
[0045] In a particular embodiment, the lateral edges of a radial opening may be inclined relative to a plane containing the axis of rotation and passing through the radial end of the fin closest to the edge when the flange is observed along the axis of rotation X by an angle P of between 5 and 45°, better between 10 and 40°, better between 15 and 35°, for example of the order of 30°.
[0046] Alternatively, at least one cavity, in particular half of the cavities, better all of the cavities, may have a circumferential edge without a radial opening provided in the edge of the flange.
[0047] At least one cavity, in particular at least half of the cavities, better all the cavities, may comprise a circumferential border with at least one portion of variable thickness. The thickness of the circumferential border may be measured on the edge along the axis of rotation X. The thickness of the portion of the circumferential border of variable thickness may increase depending on the direction of rotation of the electrical machine.
[0048] At least one cavity, in particular at least half of the cavities, better all of the cavities, may have a circumferential border with a constant thickness.
[0049] The flange may comprise an alternation of cavities comprising a circumferential edge with a radial opening formed in the edge of the flange and cavities comprising a circumferential edge of constant thickness.
[0050] The circumferential edge may be located on the outer face of the flange.
[0051] Alternatively, the flange may comprise an alternation of cavities comprising a circumferential edge with a portion of variable thickness and cavities comprising a circumferential edge of constant thickness.
[0052] The fin can have a height measured along the constant X rotation axis.
[0053] Alternatively, the fin may have a height measured along the rotation axis X that varies. The fin may have a height that varies along its entire length along a radial direction. For example, it may vary in height by having a rounded, rectangular, triangular or any other shape when the flange is viewed in section along a plane containing the rotation axis X. The height of the fin measured along the rotation axis X may be less than or equal to the thickness of the circumferential edge measured along the rotation axis X. Alternatively, the fin may include a portion whose height measured along the rotation axis X may be greater than the thickness of the circumferential edge measured along the rotation axis X.The upper part of this portion of the fin may protrude from the outer face of the flange when the flange is viewed in a radial direction by a height which may be between 1 mm and 10 mm, better between 3 mm and 5 mm. Such a fin improves air mixing and provides an additional exchange surface.
[0054] The portion of the fin extending beyond the circumferential edge along the axis of rotation X may extend over the entire length of the fin measured in a radial direction. Alternatively, the portion of the fin extending beyond the circumferential edge along the axis of rotation X may extend over only a portion of the length of the fin measured in a radial direction.
[0055] The portion of the fin extending beyond the circumferential edge along the rotation axis X may extend to the edge of the flange.
[0056] Bottom of a cavity
[0057] The internal surface of at least one cavity may comprise at least one inflection point, better exactly one inflection point, when observed in section along a plane perpendicular to a radial axis extending between two consecutive cavities.
[0058] The angle of inclination between the internal surface of a cavity and a plane perpendicular to the axis of rotation can be variable.
[0059] The angle of inclination between the internal surface of a cavity and a plane perpendicular to the axis of rotation may be between 2° and 60°, better still between 5° and 30°, even better still between 10° and 20°, being for example of the order of 15°, when observed in section along a plane perpendicular to a radial axis extending between two consecutive cavities.
[0060] At least one cavity may comprise a convex internal surface having in particular a variable radius of curvature when the flange is observed in a radial direction.
[0061] Alternatively, a cavity may have a substantially planar inner surface when the flange is viewed in section along a plane containing the axis of rotation of the rotor. Preferably, the radius of curvature of the convex inner surface may decrease when the flange is viewed in a radial direction as one approaches the edge of the flange.
[0062] Fins
[0063] At least one fin may have a variable radius of curvature when observing the flange along the axis of rotation, in particular an increasing radius of curvature when approaching the edge of the flange.
[0064] In a particular embodiment, not all of the fins are identical. In particular, a flange may comprise at least two fins having different variations in radii of curvature.
[0065] Alternatively, a flange may comprise fins that are all identical, in particular fins having the same radius of curvature and / or the same variation in radius of curvature.
[0066] Each fin may comprise an upper face contained in a plane perpendicular to the axis of rotation and a first and a second lateral face connecting the upper face to each of the adjacent cavities, at least one fin having an upper face connected to the first lateral face by a portion inclined relative to the outer face of the flange when the flange is observed in the radial direction.
[0067] The upper face of the fin may be substantially triangular in shape.
[0068] Preferably, there is no inclined portion between the upper face and the second lateral face of the fin. Alternatively, the upper face may be connected to each of the first and second lateral faces by an inclined portion.
[0069] The angle of inclination of the inclined portion relative to the upper face of the fin may be between 0° (exclusive value) and 80°, better between 5° and 50°, better between 10° and 20°, being for example of the order of 15°. Such an inclined portion makes it possible to reduce losses and to better direct the air flow towards any radial openings.
[0070] Alternatively, the flange may comprise at least one fin not comprising an inclined portion between its upper face and one of the side faces.
[0071] The first lateral face may be perpendicular to the upper face of the fin. Alternatively, the first lateral face may be inclined relative to the upper face of the fin. The angle of inclination of the first lateral face relative to the upper face of the fin may be between 90° and 120°, better between 95° and 115°, better between 100° and 110°. Such an angle of inclination allows the formation of an undercut.
[0072] The first side face may be concave in a plane perpendicular to the axis of rotation. Alternatively, the first side face may be convex in a plane perpendicular to the axis of rotation.
[0073] The fins may have different inclinations relative to a plane containing the axis of rotation and passing through the radial end of the fin closest to the edge when the flange is viewed in a section in a plane perpendicular to the axis of rotation.
[0074] In particular, the angle of inclination between the axis passing through the radial end of a fin closest to the edge and through the radial end closest to the central bore on the side of the first lateral face and a plane containing the axis of rotation and passing through the radial end of the fin closest to the edge when the flange is observed in a section in a plane perpendicular to the axis of rotation may be between 15 and 70°, better still between 20 and 60°, better still between 25 and 45°, for example of the order of 30°.
[0075] Rotor
[0076] The invention also relates, independently or in combination with the above, to a rotor of an electrical machine rotating around an axis of rotation X, the rotor comprising a rotor mass and at least one flange as described above, in particular one flange or two flanges as described above. In one embodiment, the rotor comprises a single flange as described above. Alternatively, the rotor may comprise two flanges as described above, each of the flanges being in particular arranged at one end of the rotor mass.
[0077] Preferably, the rotor is cooled by circulation of a cooling gas, in particular air.
[0078] The number of cavities in a flange can be equal to the number of rotor poles.
[0079] The number of fins on a flange can be equal to the number of rotor poles. The number of fins on a flange can be equal to the number of cavities on the flange. For example, when the rotor has 8 poles, the flange can have 8 cavities and 8 fins. The rotor rotation speed can be between 2,000 rpm and 30,000 rpm, better between 5,000 rpm and 25,000 rpm, better between 10,000 rpm and 20,000 rpm, being for example of the order of 17,000 rpm or 18,000 rpm.
[0080] The flange according to the invention allows the rotor to be cooled efficiently, even at high rotation speeds.
[0081] Electric machine
[0082] The invention also relates to an electrical machine comprising a stator and a rotor as defined above.
[0083] The stator may comprise a stator mass comprising notches formed between teeth, each notch receiving one or more winding conductors.
[0084] The machine can be used as a motor or as a generator. The machine can be reluctance. It can be a synchronous motor or, alternatively, a synchronous generator. Alternatively, it can be an asynchronous machine.
[0085] The invention may be particularly suitable for high-power machines.
[0086] The machine may comprise a single inner rotor or, alternatively, an inner rotor and an outer rotor, arranged radially on either side of the stator and coupled in rotation.
[0087] The machine can be inserted alone into a housing or inserted into a gearbox housing. In this case, it is inserted into a housing that also houses a gearbox. The housing is, for example, water-cooled.
[0088] The notches may be at least partially closed. A partially closed notch allows an opening to be provided at the air gap, which can be used, for example, to place electrical conductors for filling the notch. A partially closed notch is in particular provided between two teeth, each of which has pole shoes at their free end, which close the notch at least in part.
[0089] Alternatively, the notches may be fully closed. By "fully closed notch" is meant notches that are not open radially towards the air gap. In one embodiment, at least one notch, or even each notch, may be continuously closed on the air gap side by a bridge of material integral with the teeth defining the notch. All the notches may be closed on the air gap side by bridges of material closing the notches. The bridges of material may be integral with the teeth defining the notch. The stator mass is then free of cutouts between the teeth and the bridges of material closing the notches, and the notches are then continuously closed on the air gap side by the bridges of material integral with the teeth defining the notch.
[0090] In addition, the slots can also be closed on the side opposite the air gap by a yoke attached or in one piece with the teeth. The slots are then not open radially outwards. The stator mass can be without a cutout between the teeth and the yoke.
[0091] In one embodiment, each of the notches has a continuously closed contour. By "continuously closed" is meant that the notches have a continuous closed contour when observed in cross-section, taken perpendicular to the axis of rotation of the machine. The notch can be completely circumnavigated without encountering a cut in the stator mass.
[0092] The stator may comprise coils arranged in a distributed manner in the slots, in particular having electrical conductors arranged in a row in the slots. By "distributed" is meant that at least one of the coils passes successively through two non-adjacent slots.
[0093] The electrical conductors may not be arranged loosely in the slots but in an orderly manner. They are stacked in the slots in a non-random manner, for example, being arranged in rows of aligned electrical conductors. The stacking of the electrical conductors is, for example, a stacking according to a hexagonal lattice in the case of electrical conductors with a circular cross-section.
[0094] The stator may have electrical conductors housed in the slots. At least some, if not most, of the electrical conductors may be pin-shaped, U-shaped, or I-shaped. The pin may be U-shaped or straight, being I-shaped.
[0095] The electrical conductors can thus form a distributed winding. The winding may not be concentrated or wound on teeth. In an alternative embodiment, the stator has concentrated winding. The stator can have teeth and coils arranged on the teeth. The stator can thus be wound on teeth, in other words with non-distributed winding.
[0096] The stator teeth may have pole shoes. Alternatively, the stator teeth are without pole shoes.
[0097] The stator may have an outer casing surrounding the yoke.
[0098] The stator teeth can be made with a stack of magnetic sheets, each covered with an insulating resin, in order to limit losses due to induced currents.
[0099] Brief description of the drawings
[0100] The invention may be better understood by reading the detailed description which follows, non-limiting examples of its implementation, and by examining the attached drawing, in which:
[0101] [Fig 1] Figure 1 is a perspective view of a rotor comprising a flange according to the invention,
[0102] [Fig 2a] Figure 2a is a perspective view of the flange of Figure 1 observed from its outer face,
[0103] [Fig 2b] Figure 2b is a front view of the flange of Figure 2a,
[0104] [Fig 2c] Figure 2c is a view of the flange of Figure 2b along section C2-C2,
[0105] [Fig 2d] Figure 2d is a view of the flange of Figure 2b along section D2-D2,
[0106] [Fig 2e] Figure 2e is a view of the flange of Figure 2a observed in a radial direction,
[0107] [Fig 2f] Figure 2f is a perspective view of the flange of Figure 2a observed from its inner face,
[0108] [Fig 3a] Figure 3a is a view similar to Figure 2b of a flange according to another variant embodiment,
[0109] [Fig 3b] Figure 3b is a view similar to Figure 2e of the alternative embodiment of Figure 3a,
[0110] [Fig 3c] Figure 3c is a view of the flange of Figure 3a along section C3-
[0111] C3, [Fig 4a] figure 4a is a view similar to figure 2b of a flange according to another variant embodiment,
[0112] [Fig 4b] Figure 4b is a view similar to Figure 2e of the alternative embodiment of Figure 4a,
[0113] [Fig 4c] Figure 4c is a view of the flange of Figure 4a along section C4-C4,
[0114] [Fig 5a] Figure 5a is a view similar to Figure 2b of a flange according to another variant embodiment,
[0115] [Fig 5b] Figure 5b is a view similar to Figure 2e of the alternative embodiment of Figure 5a,
[0116] [Fig 5c] Figure 5c is a view of the flange of Figure 5a along section C5-C5,
[0117] [Fig 5d] Figure 5d is a view similar to Figure 2a of the flange of Figure 5a,
[0118] [Fig 5e] Figure 5e is a view similar to Figure 2f of the flange of Figure 5a,
[0119] [Fig 6a] Figure 6a is a view similar to Figure 2b of a flange according to another variant embodiment,
[0120] [Fig 6b] Figure 6b is a view similar to Figure 2e of the alternative embodiment of Figure 6a,
[0121] [Fig 6c] Figure 6c is a view of the flange of Figure 6a along section C6-C6,
[0122] [Fig 6d] Figure 6d is a view similar to Figure 2a of the flange of Figure 6a,
[0123] [Fig 6e] Figure 6e is a view similar to Figure 2f of the flange of Figure 6a,
[0124] [Fig 7a] Figure 7a is a view similar to Figure 2b of a flange according to another variant embodiment,
[0125] [Fig 7b] Figure 7b is a view of the flange of Figure 7a along section B7-B7,
[0126] [Fig 7c] Figure 7c is a view similar to Figure 2a of the flange of Figure
[0127] 7a, [Fig 7d] Figure 7d is a view similar to Figure 7c from another angle of view,
[0128] [Fig 8a] Figure 8a is a view similar to Figure 2b of a flange according to another variant embodiment,
[0129] [Fig 8b] Figure 8b is a view similar to Figure 2e of the alternative embodiment of Figure 8a,
[0130] [Fig 8c] Figure 8c is a view similar to Figure 8a from another angle,
[0131] [Fig 8d] Figure 8d is a view similar to Figure 2b of the flange of Figure 8a,
[0132] [Fig 9a] Figure 9a is a view similar to Figure 2b of a flange according to another variant embodiment,
[0133] [Fig 9b] Figure 9b is a view similar to Figure 9a from another angle.
[0134] Detailed description
[0135] In the figures and in the remainder of the description, the same references represent identical or similar elements.
[0136] Figure 1 illustrates an example of a rotor 1 of a rotating electrical machine, comprising a flange 10 according to the variant embodiment of Figures 2a to 2f.
[0137] The rotor 1 comprises a rotor magnetic mass 4 extending axially along the axis of rotation X of the rotor. This rotor mass 4 may be formed by a pack of magnetic rotor laminations stacked along the X axis, the laminations being for example identical and exactly superimposed. The magnetic laminations are preferably made of magnetic steel. All grades of magnetic steel may be used.
[0138] The rotor mass 4, and in particular the rotor laminations, may include housings intended to receive permanent magnets.
[0139] The rotor mass 4 has a central opening for mounting on a shaft 5. The shaft may, in the example considered, be made of a non-magnetic material, for example non-magnetic stainless steel or aluminum, or on the contrary be magnetic. Figures 2a to 2f illustrate the flange 10 of the rotor of Figure 1. The flange has a central bore 13, an inner face 12, an outer face 11 and a radially outer edge 14 extending between the inner face 12 and the outer face 11.
[0140] In the illustrated embodiment, the flange 10 comprises cavities 15 distributed circumferentially around the central bore.
[0141] The flange 10 also comprises fins 16. Each fin 16 separates two consecutive cavities 15. The fins 16 extend radially. They are all curved when the flange is observed along the axis of rotation X.
[0142] In the example shown, all fins have the same variation in curvature radius.
[0143] A portion of the cavities 15 comprises a circumferential edge 17 which connects the radial ends closest to the edge 14 of the flange of two consecutive fins surrounding this cavity, so that said cavity is delimited over its entire periphery by the two fins 16 and by the circumferential edge 17.
[0144] The remainder of the cavities 15 comprise a circumferential edge 17 with a radial opening 18 formed in the edge of the flange. This opening makes it possible to direct the air contained in the cavities towards the outside of the flange by accelerating it at the level of the radial opening 18, which makes it possible to improve cooling.
[0145] As can be seen in Figure 2c, the internal surface 150 of the cavities 15 has an inflection point, when observed in section along a plane perpendicular to a radial axis extending between two consecutive cavities 15.
[0146] The internal surface 150 of the cavities 15 has a convex internal surface with a radius of curvature which decreases when the flange 10 is observed in a radial direction when approaching the edge of the flange.
[0147] As is more particularly visible in Figure 2c, the fins 16 each comprise an upper face 161 contained in a plane perpendicular to the axis of rotation and a first 162 and a second 163 lateral face connecting the upper face 161 to each of the adjacent cavities 15. In the exemplary embodiment of Figures 2a to 2f, the fins have a portion 160 inclined relative to the outer face 11 of the flange 10 and connecting the upper face 161 to the first lateral face 162 when the flange is observed in the radial direction. In this embodiment, the first lateral face 162 is convex in a plane perpendicular to the axis of rotation X.Furthermore, the angle of inclination a, visible in Figure 2b, between the axis DI passing through the radial end of a fin 16 closest to the edge 14 and through the radial end closest to the central bore 13 on the side of the first lateral face 161, and a plane P containing the axis of rotation X and passing through the radial end of the fin 16 closest to the edge 14 when the flange is observed along a section in a plane perpendicular to the axis of rotation X, is for example of the order of 30°.
[0148] The flange 10 may also include two indexing notches 19 formed in the edge 14.
[0149] As seen in Figure 2f, the inner face 12 of the flange 10 is not smooth. The inner face has, for example, material recesses 152 at the level of the fins of the outer face 11. These material recesses 152 make it possible to limit the weight of the flange.
[0150] As is more particularly visible in Figure 2e, in this embodiment, the portion 180 of the radial opening closest to the inner face 12 of the flange 10 is curved when observed in a radial direction.
[0151] The embodiment of Figures 3a to 3c is substantially similar to the embodiment of Figures 2a to 2f. The difference between these two embodiments is that the portion 180 of the radial opening 18 closest to the inner face 12 of the flange of Figure 3b is rectilinear when observed in a radial direction.
[0152] In the embodiment of Figures 4a to 4c, the flange comprises six cavities 15. All the cavities 15 comprise a circumferential edge 17 with a radial opening 18 formed in the edge 14 of the flange.
[0153] As can be seen in Figure 4b, in this embodiment, the portion 180 of the radial opening 18 closest to the inner face 12 of the flange is rectilinear when observed in a radial direction.
[0154] As can be seen in Figure 4c, the cavities have an internal surface 150 which is substantially flat when the flange 10 is observed in section along a plane containing the rotation axis X of the rotor.
[0155] Another alternative embodiment of a flange 10 is illustrated in Figures 5a to 5e. In this embodiment, the flange 10 comprises eight cavities 15. Each cavity 15 comprises a circumferential edge 17 which connects the radial ends 166 closest to the edge 14 of the flange of two consecutive fins 16 surrounding this cavity 15, so that said cavity 15 is delimited over its entire periphery by the two fins 16 and by the circumferential edge 17.
[0156] In the embodiment of Figures 5a to 5e, half of the cavities 15 have a circumferential border 17 of constant thickness.
[0157] The other half of the cavities 15 comprises a circumferential edge 17 with at least one portion of variable thickness 170. As can be seen in FIG. 5b, the thickness e measured along the axis of rotation X of this portion of variable thickness 170 increases along the direction of rotation of the electrical machine.
[0158] In this embodiment, the internal surface 150 of the cavities is convex in shape. This internal surface has a variable radius of curvature when the flange 10 is observed in section along a radial plane as in FIG. 5c. According to this section, the radius of curvature of the internal surface 150 decreases as one approaches the edge 17 of the flange.
[0159] As visible in figure 5 e, the inner face 12 of the flange does not have material recesses 152 at the level of the fins 16 of the outer face 11.
[0160] The embodiment of Figures 6a to 6e is substantially similar to the embodiment of Figures 5a to 5e. The difference between these two embodiments is that in the embodiment of Figures 6a to 6e all the cavities 15 have a circumferential border 17 with at least one portion of variable thickness 170.
[0161] The embodiment of Figures 7a to 7d is substantially similar to the embodiment of Figures 5a to 5e. The difference between these two embodiments is that in the embodiment of Figures 7a to 7d all the cavities 15 have a circumferential border 17 of constant thickness.
[0162] Figures 8a to 8d illustrate an embodiment substantially similar to the embodiment of Figures 2a to 2e. In this embodiment, the radial openings 18 have lateral edges 181 that flare when the edge 14 of the flange is viewed in a radial direction. The edges 181 of the radial opening 18 flare in the direction of the outer face 11 of the flange.
[0163] Figures 9a and 9b illustrate an embodiment substantially similar to the embodiment of Figures 2a to 2e. Unlike the embodiment of Figures 2a to 2e, in this embodiment, the first lateral face 162 is concave in a plane perpendicular to the axis of rotation. In addition, in this exemplary embodiment, the lateral edges 181 of the radial opening 18 are inclined relative to the plane P containing the axis of rotation X and passing through the radial end of the fin 16 closest to the edge 14 when the flange is observed in a section in a plane perpendicular to the axis of rotation X.In the example shown, the angle of inclination P between the axis D2 containing one of the lateral edges 181 of the radial opening 18 and a plane P containing the axis of rotation X and passing through the radial end of the fin 16 closest to the edge 14 when the flange is observed in a section in a plane perpendicular to the axis of rotation X is of the order of 30°. In all the embodiments of FIGS. 1 to 9b, the fins have a height measured along the axis of rotation X that is constant. In addition, in these embodiments the height of the fins measured along the axis of rotation X is substantially equal to the thickness of the circumferential edge measured along the axis of rotation X.
[0164] The invention is not limited to what has just been described. For example, the flange may have a different number of cavities. It may also have fins and / or cavities of different sizes and / or shapes.
Claims
Claims 1. Flange (10) of a rotor of an electrical machine rotating around an axis of rotation X, the flange comprising an inner face (12) facing a rotor mass (4) of the rotor, an outer face (11) opposite the inner face, a radially outer edge (14) extending between the inner face and the outer face, and a central bore (13), the flange comprising: - at least two cavities (15) provided on the outer face (11) of the flange and distributed circumferentially around the central bore, each cavity being delimited at least by one circumferential edge (17) extending along the edge of the flange, and - at least one fin (16) separating two consecutive cavities, the fin extending substantially radially and being curved when the flange is observed along the axis of rotation X, the flange (10) being devoid of an axially through opening other than the central bore (13).
2. Flange (10) of a rotor of an electrical machine rotating around an axis of rotation X, the flange comprising an inner face (12) facing a rotor mass (4) of the rotor, an outer face (11) opposite the inner face, a radially outer edge (14) extending between the inner face and the outer face, and a central bore (13), the flange comprising: - at least two cavities (15) provided on the outer face (11) of the flange and distributed circumferentially around the central bore, each cavity being delimited at least by one circumferential edge (17) extending along the edge of the flange, and - at least one fin (16) separating two consecutive cavities, the fin extending substantially radially and being curved when the flange is observed along the axis of rotation X, at least one cavity (15) comprising a convex internal surface having in particular a variable radius of curvature when the flange is observed in a radial direction.
3. Flange (10) of a rotor of an electrical machine rotating around an axis of rotation X, the flange comprising an inner face (12) facing a rotor mass (4) of the rotor, an outer face (11) opposite the inner face, a radially outer edge (14) extending between the inner face and the outer face, and a central bore (13), the flange comprising: - at least two cavities (15) provided on the outer face (11) of the flange and distributed circumferentially around the central bore, each cavity being delimited at least by one circumferential edge (17) extending along the edge of the flange, and - at least one fin (16) separating two consecutive cavities, the fin extending substantially radially and being curved when the flange is observed along the axis of rotation X, at least one cavity (15) comprising an internal surface, the angle of inclination between the internal surface of a cavity and a plane perpendicular to the axis of rotation being between 2° and 60°, better still between 5° and 30°, even better still between 10° and 20°, when observed in section along a plane perpendicular to a radial axis extending between two consecutive cavities.
4. Flange (10) of a rotor of an electrical machine rotating around an axis of rotation X, the flange comprising an inner face (12) facing a rotor mass (4) of the rotor, an outer face (11) opposite the inner face, a radially outer edge (14) extending between the inner face and the outer face, and a central bore (13), the flange comprising: - at least two cavities (15) provided on the outer face (11) of the flange and distributed circumferentially around the central bore, each cavity being delimited at least by one circumferential edge (17) extending along the edge of the flange, and - at least one fin (16) separating two consecutive cavities, the fin extending substantially radially and being curved when the flange is observed along the axis of rotation X, the circumferential edge (17) connecting the radial ends closest to the edge of the flange of two consecutive fins surrounding a cavity.
5. Flange according to one of the three preceding claims, the flange (10) being devoid of an axially through opening other than the central bore (13).
6. Flange according to any one of the preceding claims, at least one cavity (15), in particular half of the cavities, better all the cavities, comprising a circumferential edge (17) comprising a radial opening (18) formed in the edge (14) of the flange.
7. Flange according to the preceding claim, the portion (180) of the radial opening (18) closest to the inner face of the flange being curved when observed in a radial direction or the portion (180) of the radial opening (18) closest to the inner face of the flange being rectilinear when observed in a radial direction.
8. Flange according to any one of the preceding claims, at least one cavity (15), in particular at least half of the cavities, better all the cavities, comprising a circumferential edge (17) with at least one portion of variable thickness (170).
9. Flange according to the preceding claim, the thickness (e) of the portion (170) of the circumferential edge of variable thickness increasing according to the direction of rotation of the electrical machine.
10. Flange according to any one of the preceding claims, at least one cavity (15), in particular at least half of the cavities, better all the cavities, comprising a circumferential edge (17) with a constant thickness.
11. Flange according to the preceding claim when it depends on claim 1 or claim 5, comprising an alternation of cavities (15) comprising a circumferential edge (17) with a radial opening (18) formed in the edge (14) of the flange and of cavities (15) comprising a circumferential edge (17) of constant thickness.
12. Flange according to claim 10, at least one cavity (15), in particular at least half of the cavities, better all the cavities, comprising a circumferential edge (17) with at least one portion of variable thickness (170), the flange comprising an alternation of cavities (15) comprising a circumferential edge (17) with a portion (170) of variable thickness and cavities (15) comprising a circumferential edge (17) of constant thickness.
13. Flange according to any one of the preceding claims, the internal surface (150) of at least one cavity (15) comprising at least one inflection point, better exactly one inflection point, when observed in section along a plane perpendicular to a radial axis extending between two consecutive cavities.
14. A flange according to any one of the preceding claims, at least one cavity (15) comprising a convex internal surface having a variable radius of curvature when the flange is observed in a radial direction.
15. Flange according to any one of the preceding claims, at least one fin (16) having a variable radius of curvature when the flange is observed along the axis of rotation, in particular an increasing radius of curvature when approaching the edge of the flange.
16. Flange according to any one of the preceding claims, each fin (16) comprising an upper face (161) contained in a plane perpendicular to the axis of rotation and a first (162) and a second (163) lateral face connecting the upper face to each of the adjacent cavities (15), at least one fin (16) having an upper face (161) connected to the first lateral face (162) by an inclined portion (160) relative to the outer face (11) of the flange when the flange is observed in the radial direction.
17. Rotor of an electrical machine rotating around an axis of rotation X, the rotor comprising a rotor mass (4) and at least one flange (10) according to any one of the preceding claims, in particular one or two flanges according to any one of the preceding claims.
18. Rotor according to the preceding claim, being cooled by circulation of a cooling gas, in particular air.