EP4115498A1 - Rotor for an axial flux electromagnetic machine - Google Patents

Rotor for an axial flux electromagnetic machine

Info

Publication number
EP4115498A1
EP4115498A1 EP21709023.2A EP21709023A EP4115498A1 EP 4115498 A1 EP4115498 A1 EP 4115498A1 EP 21709023 A EP21709023 A EP 21709023A EP 4115498 A1 EP4115498 A1 EP 4115498A1
Authority
EP
European Patent Office
Prior art keywords
edges
notch
rotor
permanent magnet
relief
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21709023.2A
Other languages
German (de)
French (fr)
Inventor
Jere Kolehmainen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ampere Sas
Whylot SAS
Original Assignee
Renault SAS
Whylot SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Renault SAS, Whylot SAS filed Critical Renault SAS
Publication of EP4115498A1 publication Critical patent/EP4115498A1/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2793—Rotors axially facing stators
    • H02K1/2795—Rotors axially facing stators the rotor consisting of two or more circumferentially positioned magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/28—Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/24—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets axially facing the armatures, e.g. hub-type cycle dynamos

Definitions

  • the present invention relates generally to electrical machines with axial flow.
  • the invention finds a particularly advantageous application in the electric motors of electric or hybrid motor vehicles.
  • An axial flow electric machine generally comprises two stators and a rotor, air gaps separating these two types of elements.
  • the rotor carries a series of permanent magnets, while a series of coils is carried by the stators.
  • the rotor When the coils are supplied with an electric current, the rotor, which is secured to the output shaft of the motor, is subjected to a torque resulting from the magnetic field (the magnetic flux created being an axial flux for an electric machine axial flow).
  • a judicious way to increase the mechanical power delivered by an electric motor is to increase the rotational speed of the rotor. It is also possible to increase its torque, but this has certain disadvantages such as an increase in the weight and / or the size of the engine or the increase in losses due to the Joule effect.
  • Permanent magnets the shape of which is adapted to the shape of the notches, are inserted into these notches.
  • the edges of the permanent magnets are grooved so that they can fit over ribs provided along the edges of the notches.
  • a layer of glue is placed in the groove to ensure the fixing.
  • the main disadvantage of such a rotor lies in the possibility of detachment of the permanent magnets from the body of the rotor in the event of rotation of the rotor at very high speed. Indeed, the permanent magnets undergo strong radial stresses, due to the centrifugal force when the rotor is rotating about its axis of rotation.
  • the present invention proposes to strengthen the fixing of each permanent magnet in the body of the rotor.
  • a rotor as defined in the introduction, in which at least one of the edges of the notch extends in length along an average line and has a cross section at this average line of which the shape varies along the mean line so as to form at least a first relief and in which at least part of one of the edges of the permanent magnet, facing said at least one of the edges of the notch, has at least one second relief of corresponding shape, in negative, to match the shape of said at least one first relief.
  • a larger bonding surface between the permanent magnet and the body ensures better maintenance of the assembly and in particular better resistance to centrifugal forces.
  • the normal to the bonding surface having a direction which is also variable, the stresses due to the centrifugal forces are distributed between tensile stresses and shear stresses. The effectiveness of the bonding is thereby increased. The probability of detachment of the permanent magnets from the body is then greatly reduced.
  • a gap is provided between said at least one of the edges of the notch and said at least one of the edges of the permanent magnet, said gap extending over at least part of the length of said at least one edge of the notch and over only part of the thickness of said body.
  • the effect of a layer of glue or varnish enveloping the rotor is greatly improved.
  • the gap increases the thickness of the layer of glue or varnish between the edge of the notch and the edge of the permanent magnet.
  • This layer is thicker and therefore more elastic, this makes it possible to better absorb the slight movements of the permanent magnet relative to the body due to centrifugal forces.
  • said permanent magnet comprises a magnetic body and a casing which at least partially surrounds the magnetic body, said magnetic body has a shape in relief corresponding to that of said at least one second relief. Adapting the shape of the magnetic body to the shape of the edge of the notch makes it possible to maximize the volume of the magnetic body in relation to the total volume of the permanent magnet (and therefore in relation to the volume of the rotor) and thus to improve performance magnets of the rotor.
  • a hoop surrounds the periphery of the assembly formed by said body and said at least one permanent magnet, and, in the disassembled state, the internal diameter of the hoop is partly less than the external diameter of said assembly.
  • said at least one of the edges of the notch has a plurality of first reliefs and said at least one of the edges of the permanent magnet has a plurality of second reliefs of corresponding shape, in negative, to match the shape of the plurality of first reliefs;
  • notch Said one of the edges of the notch has a rib or a groove extending over at least part of its length and said permanent magnet respectively has a groove or a rib of corresponding shape (to preferably form a tight fit);
  • said at least one notch extends over the entire thickness of said body.
  • Figure 1 is a schematic front view of a machine rotor electric.
  • Figure 2 is a schematic exploded perspective view of part of the rotor of Figure 1 showing a permanent magnet before it is inserted into a notch.
  • Figure 3 is a sectional view along the plane A-A of Figure 2.
  • Figure 4 is a sectional view along the plane B-B of Figure 2.
  • Figure 5 is a sectional view along the plane C-C of Figure 1.
  • Figure 6 is a sectional view along the plane D-D of Figure 1.
  • Figure 7 schematically illustrates Figure 6 before assembly of the rotor.
  • FIG. 1 there is shown a rotor 100 of an electric machine.
  • the rotor 100 includes a body 110, a plurality of permanent magnets 130, and a hoop 150.
  • the body 110 has the overall shape of a disc, in the sense that it is substantially circumscribed to a cylinder of revolution about an axis hereinafter called axis of rotation A1. It has a height (dimension of the body along the axis of rotation A1) which is much less than the diameter. In the following description, this height is called the thickness of the body 110.
  • the body 110 thus has two plane circular faces, mutually parallel and perpendicular to the axis of rotation A1 of the rotor 100, one of the two faces being visible in the figure. 1.
  • the body 110 has a central recess adapted to receive a transmission shaft extending along the axis of rotation A1.
  • the rotor 100 is intended to be fixed to this transmission shaft which it is intended to drive.
  • the body 110 can for example be made from aluminum, steel, iron, titanium or an alloy containing these metals. It is for example produced by a stack of metal sheets with a thickness less than or equal to a millimeter. These metal plates are here curved and stacked radially. They extend over the entire height of the body 101. Thus, losses in the stator due to eddy currents are limited.
  • the body 110 is preferably made of a composite material reinforced with glass or carbon fibers.
  • the body is composed of three layers, two outer layers 112, 114 and a central layer 113, having generally identical shapes. These three layers, stacked along the axis of rotation A1, form body 110. Alternatively, body 110 may be machined from a single block.
  • the body 110 has a plurality of notches 120 recessed in its peripheral edge.
  • the body 110 has twelve identical notches 120.
  • the notches 120 are distributed evenly over the entire periphery of the body 110. This makes it possible to ensure a good balance of the rotor 110 when the latter is rotating.
  • the body 110 comprises a central hub and a plurality of branches extending from the hub in substantially radial directions with respect to the axis of rotation A1.
  • the branches become thinner towards the periphery of the rotor 100.
  • the branches, 12 in number in FIG. 1 are all identical and regularly distributed around the hub so as to be two separate. Two by one space, each pair of adjacent branches then defines one of the notches 120.
  • these notches are thus radially open towards the outside, that is to say towards the periphery of the rotor 100.
  • each notch 120 preferably extends over the entire thickness of the body 110. This has the advantage of providing two opposing working surfaces. Such a rotor 100 can thus for example be framed by two stators to provide more mechanical power.
  • Each notch 120 has an overall U shape with spaced arms, with two side edges 121 of substantially radial extension and a bottom here called inner edge 122.
  • the inner edge 122 is rectilinear (it is a flat surface).
  • the inner edge 122 may be curved, for example with the same radius of curvature as the body 110.
  • the notch 120 could have a V-shape and have only two side edges, the inner edge 122 then being assimilated to the edge formed by the contact of the two side edges 121.
  • each notch 120 generally has three straight edges including two side edges 121 which move away from each other from the center of the body 110 to the outside of the latter.
  • This geometry allows a simple radial insertion of the permanent magnets 130 in the notches 120, by a simple movement of engagement in a radial direction A2 (relative to the axis of rotation A1).
  • the side edges of a notch 120 are each provided with a groove 160 extending lengthwise in a substantially radial direction.
  • Each groove 160 has a U-shaped cross section and is delimited between two side walls 161. As shown in Figures 3 and 4, the side walls 161 defining this U are here formed by the two outer layers 112, 114 of the body 110.
  • Each groove 160 is here located halfway between the two circular faces of the body 110.
  • the inner edge 122 may have a relief, for example formed by a difference in radial extension of the outer layers 112, 114 relative to the central layer 113.
  • the inner edge 122 may therefore have a groove similar to the groove 160 of a side edge 121 of the notch 120.
  • the permanent magnet 130 then has a complementary shape to fit into this relief.
  • Each groove 160 is designed to interlock with a rib 170 provided in correspondence with the permanent magnet 130, projecting from its side edges.
  • This groove and rib type assembly ensures a high resistance of the rotor 100 with respect to the axial forces undergone by the permanent magnets 130 when the electric motor is in operation and the permanent magnets 130 are attracted towards the coils of the stator.
  • each rib protrudes from the side edge of the notch and that each groove extends recessed into one of the side edges of the permanent magnet 130.
  • Each side edge 121 of the notch 120 extends in length (here in a direction orthogonal to the axis of rotation A1) along a mean line D1.
  • the mean line D1 is a straight line.
  • the mean line could be a curve.
  • the mean line D1 is defined here as the line passing on average as close as possible to the geometric centers of the surfaces formed by the sections of the lateral edge (the section plane considered being orthogonal to the radius along which this edge extends substantially) .
  • the mean line can for example be defined as a linear regression line on the positions of the geometric centers of the surfaces formed by the sections of the lateral edge.
  • Each permanent magnet 130 has a shape adapted to the notch 120 in which it is inserted. As shown in Figures 1 and 2, each magnet permanent 130 here therefore has a generally trapezoidal shape. Each permanent magnet 130 has a thickness (dimension along the axis of rotation A1) substantially equal to the thickness of the body 110.
  • Each permanent magnet 130 thus has two magnet edges 131 located opposite the side edges 121 of the notch 120 in which it is inserted.
  • the edges of the magnet 131 have an almost identical geometry, in negative, to the geometry of the side edges 121.
  • the edges of the magnet 131 are in particular provided with a rib 170 which fits together, except for an assembly clearance, in the groove 160.
  • each notch 120 extending in length along the mean line D1 associated with it, has a cross section to this mean line, the shape of which varies from along the middle line so as to form at least a first relief 140, and at least part of the edge of the magnet 131 in contact with the lateral edge 121 has a second relief 141 of corresponding shape, in negative, to match the shape of the first relief 140.
  • the two side edges of the notches 120 are identical.
  • FIG. 3 there is shown a first section plane AA of the side edge 121 of Figure 2 which shows a first cross section at a first relief 140.
  • Figure 4 there is shown a second section plane BB of the side edge 121 of FIG. 2 which represents a second transverse section in a zone devoid of a first relief 140.
  • the shape of the cross section to the mean line D1 varies along the mean line D1 between the two section planes A-A and B-B.
  • the side walls 161 defining the groove 160 are higher for the first cross section than for the second cross section.
  • the groove 160 is deeper at a first relief 140 than in an area without a first relief 140.
  • the shape of the cross section at the mean line D1 is a U shape, the depth of which varies linearly by section along the mean line D1 between a minimum depth and a maximum depth.
  • the reliefs 140, 141 increase the contact surface between the permanent magnet 130 and the body 110, more precisely between the side edge 121 of notch 120 and magnet edge 131.
  • a layer of glue 190 is disposed between the permanent magnet 130 and the body 110 at the notch 120 (on the body 110 and / or on the permanent magnet 130 ).
  • the purpose of this layer of glue 190 is to ensure that the permanent magnet 130 is held in the notch 120 when the rotor 100 is rotating and the permanent magnet 130 is subjected to significant centrifugal forces (all the more as the rotation speed is high).
  • the directions normal to the contact surface that is to say to the bonding surface, are varied. This makes it possible to better distribute the stresses to which the adhesive layer is subjected between tensile stresses and shear stresses when the rotor 100 is rotating.
  • the permanent magnet 130 is mainly retained by the lateral grooves 160.
  • each side edge 121 has a plurality of first reliefs 140 and each magnet edge 131 has a plurality of corresponding second reliefs 141.
  • the bonding surface is thus further increased which increases the retention of the permanent magnet 130 in the notch 120.
  • each side edge 121 has five first reliefs 140 on each of the two side walls 161 defining the groove 160.
  • the first reliefs 140 give the end faces of the side walls 161 of the groove 160 a zigzag or sawtooth shape which consists of broken lines.
  • each edge of the magnet 131 has ten second reliefs 141: five on each side of the rib 170.
  • first reliefs 140 are reliefs projecting from the end faces of the side walls 161 of the groove 160 and the second reliefs 141 are recesses in the magnet edge 131.
  • the first reliefs 140 located on the side edges 121 of the notches 120 could be recesses and the second reliefs 141 could protrude from the edge of the magnet 131 Provision can also be made for the first reliefs 141 to include both projecting reliefs and recesses and for the second reliefs 141 to include corresponding recesses and projecting reliefs.
  • each first relief 140 has flat faces. This implies that the corresponding second reliefs 141 also have flat faces.
  • each first relief 140 has two rectangular end faces connected together by a ridge and two triangular side faces (here isosceles triangles).
  • the magnet edge 131 is in contact along its entire length with the side edge 121 of the notch 120.
  • the contact area between the permanent magnet 130 and the notch 120 is maximum.
  • the permanent magnet edge 131 is in contact over its entire length with the side edge 121 of the notch 120 means that the side edge 121 has a single contact surface contiguous with the magnet edge 131 which is associated with it, this contiguous surface extending from the inner edge 122 to the periphery of the body 110.
  • the interlocking can then be qualified as complete.
  • each first relief 140 is oriented so that the permanent magnet 130 can be engaged in the notch 120 in a radial direction A2.
  • each first relief 141 is always oriented towards the outside of the notch 120 (towards the periphery), as opposed to the inner edge 122.
  • the surface of each first relief 141 is thus never oriented towards the interior edge 122.
  • the surface of each first relief 141 is orthogonal with the surface of the interior edge 122.
  • the surfaces of each first relief 141 are oriented towards the outside of the notch 120.
  • outside of the notch is also meant, at the extreme limit, an orientation according to a direction perpendicular to the radial direction A2.
  • a gap 143 is located over at least part of the length of each side edge 121, between the body 110 and the permanent magnet 130. This interstice extends over only part of the thickness of body 110.
  • this gap 143 provision can be made, for example, for the height of the rib 170 provided to project from each edge of the magnet 131 to be slightly greater than the depth of the corresponding groove 160.
  • the first 140 and second 141 reliefs face each other at a short distance.
  • the outer glue layer can be deposited in the form of an aerosol by spraying or else by immersion of the rotor. 100 in a bath of liquid glue.
  • the gap 143 increases the thickness of the layer of adhesive between the side edge 121 and the permanent magnet 130 (that is, between the side edge 121 and the magnet edge 131).
  • the glue layer is thicker and therefore more elastic. This makes it possible to better absorb the slight movements of the permanent magnet 130 relative to the body 110 when it is subjected to centrifugal forces.
  • the glue may warp slightly without cracking or breaking.
  • each permanent magnet 130 has a plane inner edge 132 and an outer edge 180.
  • the inner edge 132 is applied against the inner edge 122 of the notch 120.
  • the outer edge 180 is flush with the periphery of the body 110.
  • the outer edge 180 is curved and has the same radius of curvature as the body 110.
  • the peripheral surface of the rotor 110 is cylindrical.
  • Each permanent magnet 130 has a casing 135 and a magnetic body 136.
  • the magnetic body 136 is the part of the permanent magnet 130 which generates a static magnetic field. It can for example be composed of a neodymium iron boron or samarium cobalt assembly.
  • each magnetic body 136 is composed of a plurality of unit magnets whose length extends over the entire thickness of the permanent magnet 130 and whose section is hexagonal. Using a plurality of individual magnets reduces Focault current losses compared to a single magnet of the same size.
  • the unit magnets could have a different section, for example square, triangular or round.
  • the envelope 135 surrounds the magnetic body 136 at the edges of the notch 120 and the periphery of the body 110.
  • the envelope 135 does not cover the magnetic body 136 at its main faces.
  • the envelope 135 is preferably made of a non-magnetic material.
  • the envelope 135 can be made of plastic or resin, for example an epoxy resin.
  • the second reliefs 141 are formed by the envelope 135.
  • the magnetic body 136 preferably has reliefs (at the edges of the magnet 131) of shapes corresponding to the second reliefs 141.
  • the magnetic body 136 of each permanent magnet 130 has a sawtooth profile.
  • the magnetic body 136 also has a recess at the level of this second relief 141. Closely following the shape of the second relief 141 makes it possible to maximize the volume of the magnetic body 136 relative to the permanent magnet 130.
  • This adaptation of the magnetic body 136 to the second reliefs 141 can be achieved by arranging the individual magnets according to the shape of the notch 120.
  • the rotor hoop 150 shown in Figure 1, surrounds the periphery of the body 110 and the permanent magnets 130 by their outer edges 180.
  • the role of the hoop 150 is to provide an additional holding means (against the forces centrifugal) for the permanent magnets 130 when the rotor 100 is rotating.
  • the hoop 150 is made of composite materials such as glass fibers, carbon fibers or polymer fibers embedded in a resin.
  • the hoop 150 has an annular shape.
  • the internal diameter of the hoop 150 is strictly less than the external diameter of the body 110.
  • the hoop 150 When it is put in place, the hoop 150 then undergoes a slight elastic deformation. Thus, the hoop 150 is preloaded and provides more support to the permanent magnets 130.
  • each permanent magnet 130 has a different shape, with three faces here.
  • a first face 181 extends along a cylindrical surface of revolution around the axis of rotation A1, in the extension of the periphery of the body 110 while a second face 183 extends along a cylindrical surface of revolution of diameter more big.
  • the hoop 150 has an internal surface adapted to that of the external edges 180 of the magnets.
  • the inner surface of the hoop 150 therefore also has three faces.
  • each permanent magnet prefferably has a single frustoconical surface of revolution around the axis of rotation.
  • the internal surface of the hoop is then a corresponding frustoconical surface.
  • the profile of the hoop then has the shape of a rectangular trapezoid.
  • the face of the hoop 150 of larger diameter has a diameter equal, except for a clearance, to the outer diameter of the body 110 and the first faces 181 of the outer edges 180 of the permanent magnets 130.
  • the hoop 150 can thus be put in placed by this side of the body 110.
  • the hoop 150 then deforms as it is inserted because the other faces of the inner surface of the hoop 150 have diameters smaller than the outer diameter of the body 110.
  • the hoop 150 is itself also glued to the body 110 and to the permanent magnets 130. Thanks to this hoop 150 which, in the disassembled state, has an internal diameter partly smaller than the external diameter of the body 110, it is possible to have a small amount of glue which is distributed during the installation of the hoop 150.
  • Figure 6 illustrates the rotor 100, along the section plane D-D of Figure 1, once the permanent magnet 130 has been inserted into the notch 120 and once the band 150 in place.
  • a first layer of glue 190 is distributed between the notch 120 and the permanent magnet 130.
  • the first layer of glue 190 is in particular distributed in the gap 143 between the notch edge 121 and the permanent magnet 130.
  • a second layer of adhesive 191 is distributed between the permanent magnet 130 and the hoop 150.
  • Figure 7 illustrates, still along the sectional plane D-D of Figure 1, the rotor 100 before the permanent magnet 130 is inserted into the notch 120 and before the band 150 is in place.
  • the first layer of glue 190 is distributed in the groove 160.
  • the second layer of glue 191 is distributed at the level of the third face 182 of the outer edge 180 of the permanent magnet 130.
  • the rotor 110 is assembled by a radial insertion of the permanent magnet 130 in the notch 120.
  • the hoop 150 can be put in place at the same time or subsequently.
  • the hoop 150 When it is put in place, the hoop 150 translates in the direction of the axis of rotation A1.
  • the establishment of the hoop 150 here makes it possible to distribute the second layer of glue 190 along the outer edge 180.
  • the internal dimensions of the hoop 150 mean that its installation also makes it possible to constrain l 'permanent magnet 130 in the direction of the notch 120. This constraint allows or facilitates the insertion of the rib 170 in the groove 160.
  • the first layer of adhesive 190 is formed. distributed along the edge of notch 121.
  • a varnish or an external layer of glue enveloping the rotor 100 can be deposited. This can make it possible to fill in the spaces, between the notch 120 and the permanent magnet 130 and between the permanent magnet 130 and the hoop 150, where the first layer of glue 190 and respectively the second layer of glue 191 would not have come together. distributed. In particular, this can make it possible to fill the gap 143 with glue.
  • the shape and orientation of the first reliefs 140 and of the second reliefs 141 allow complete engagement of the permanent magnets 130 in the notches 120.
  • the permanent magnets 130 may be, in one first step, inserted into the central layer 113 of the body 110.
  • the ribs 170 bordering the permanent magnets 130 are in contact with the bottom of the grooves 160 provided in the notches 120.
  • the outer layers 112, 114 of the body 110 are plated on either side of the central layer 113.
  • the first reliefs 140 are made in these outer layers 112, 114 of the body 110 and are inserted into the second reliefs 141 made in the envelope 135 of the permanent magnets 130.
  • the shape and orientation of the first and second reliefs 140, 141 is not constrained by the radial insertion of the permanent magnets 130.
  • Other shape variants for the first reliefs 141 are conceivable, for example shapes blocking a radial exit of the permanent magnets 130 when the rotor 100 is rotating.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

The invention relates to a rotor (100) for an axial flux electromagnetic machine, comprising a body (110) in the overall shape of a disc, with a peripheral edge having at least one slot (120) delimited by at least two edges (121), and at least one permanent magnet (130) which is situated in said slot and which has at least two edges (131) facing the at least two edges of the slot. According to the invention, one of the edges of the slot extends longitudinally along a mean line (D1) and has a cross section, at this mean line, the shape of which varies along the mean line so as to form at least one first relief (140), and a part of one of the edges of the permanent magnet has at least one second relief (141) of corresponding shape, in negative, so as to conform to the shape of said at least one first relief.

Description

ROTOR POUR MACHINE ELECTROMAGNÉTIQUE A FLUX AXIAL ROTOR FOR ELECTROMAGNETIC AXIAL FLOW MACHINE
DOMAINE TECHNIQUE DE L'INVENTION TECHNICAL FIELD OF THE INVENTION
[0001] La présente invention concerne de manière générale les machines électriques à flux axial. The present invention relates generally to electrical machines with axial flow.
[0002] Elle concerne plus particulièrement un rotor de machine électrique à flux axial comprenant : [0002] It relates more particularly to an axial flow electric machine rotor comprising:
- un corps en forme globale de disque, avec un bord périphérique présentant au moins une encoche délimitée par au moins deux bords, et - a body in the overall shape of a disc, with a peripheral edge having at least one notch delimited by at least two edges, and
- au moins un aimant permanent qui est situé dans ladite encoche et qui présente au moins deux bords respectivement en regard des au moins deux bords de l’encoche. - at least one permanent magnet which is located in said notch and which has at least two edges respectively facing the at least two edges of the notch.
[0003] L’invention trouve une application particulièrement avantageuse dans les moteurs électriques de véhicules automobiles électriques ou hybrides. The invention finds a particularly advantageous application in the electric motors of electric or hybrid motor vehicles.
ETAT DE LA TECHNIQUE STATE OF THE ART
[0004] Une machine électrique à flux axial comprend généralement deux stators et un rotor, des entrefers séparant ces deux types d’éléments. Le rotor porte une série d'aimants permanents, tandis qu'une série de bobines est portée par les stators. [0004] An axial flow electric machine generally comprises two stators and a rotor, air gaps separating these two types of elements. The rotor carries a series of permanent magnets, while a series of coils is carried by the stators.
[0005] Quand les bobines sont alimentées par un courant électrique, le rotor, qui est solidarisé à l'arbre de sortie du moteur, est soumis à un couple résultant du champ magnétique (le flux magnétique créé étant un flux axial pour une machine électrique à flux axial). When the coils are supplied with an electric current, the rotor, which is secured to the output shaft of the motor, is subjected to a torque resulting from the magnetic field (the magnetic flux created being an axial flux for an electric machine axial flow).
[0006] La demande de machines électriques pouvant délivrer une puissance mécanique élevée tout en gardant un poids et un encombrement réduits est actuellement très forte. [0006] The demand for electrical machines that can deliver high mechanical power while keeping a reduced weight and size is currently very high.
[0007] Une façon judicieuse d’augmenter la puissance mécanique délivrée par un moteur électrique consiste à augmenter la vitesse de rotation du rotor. Il est également possible d’augmenter son couple mais cela présente certains désavantages comme l’augmentation du poids et/ou de l’encombrement du moteur ou l’augmentation des pertes par effet Joule. [0007] A judicious way to increase the mechanical power delivered by an electric motor is to increase the rotational speed of the rotor. It is also possible to increase its torque, but this has certain disadvantages such as an increase in the weight and / or the size of the engine or the increase in losses due to the Joule effect.
[0008] Ainsi, pour garder des moteurs à faible encombrement, des rotors légers et aptes à supporter des vitesses de rotation élevées ont été conçus. [0009] On connaît notamment du document US2011006631 un tel rotor. Ce rotor présente une forme globale de disque, avec des encoches en creux dans son bord périphérique. [0008] Thus, to keep the motors compact, lightweight rotors capable of withstanding high rotational speeds have been designed. Such a rotor is known in particular from document US2011006631. This rotor has the overall shape of a disc, with recessed notches in its peripheral edge.
[0010] Des aimants permanents, dont la forme est adaptée à la forme des encoches, sont insérés dans ces encoches. Pour parfaire la fixation de ces aimants permanents dans les encoches, les bords des aimants permanents sont rainurés de façon à pouvoir s’emboîter sur des nervures prévues le long des bords des encoches. Classiquement une couche de colle est disposée dans la rainure pour assurer la fixation. Permanent magnets, the shape of which is adapted to the shape of the notches, are inserted into these notches. To complete the fixing of these permanent magnets in the notches, the edges of the permanent magnets are grooved so that they can fit over ribs provided along the edges of the notches. Conventionally, a layer of glue is placed in the groove to ensure the fixing.
[0011] Le principal désavantage d’un tel rotor réside dans la possibilité de détachement des aimants permanents du corps du rotor en cas de rotation du rotor à très grande vitesse. En effet, les aimants permanents subissent de fortes contraintes radiales, dues à la force centrifuge lorsque le rotor est en rotation autour de son axe de rotation. [0011] The main disadvantage of such a rotor lies in the possibility of detachment of the permanent magnets from the body of the rotor in the event of rotation of the rotor at very high speed. Indeed, the permanent magnets undergo strong radial stresses, due to the centrifugal force when the rotor is rotating about its axis of rotation.
[0012] Il convient donc de concevoir un rotor qui puisse mieux résister aux efforts qu’il subit tout en maximisant le flux magnétique dans l’entrefer. [0012] It is therefore necessary to design a rotor which can better withstand the forces to which it is subjected while maximizing the magnetic flux in the air gap.
PRESENTATION DE L'INVENTION PRESENTATION OF THE INVENTION
[0013] Afin de remédier à l’inconvénient précité de l’état de la technique, la présente invention propose de renforcer la fixation de chaque aimant permanent dans le corps du rotor. In order to overcome the aforementioned drawback of the state of the art, the present invention proposes to strengthen the fixing of each permanent magnet in the body of the rotor.
[0014] Plus particulièrement, on propose selon l’invention un rotor tel que défini en introduction, dans lequel au moins un des bords de l’encoche s’étend en longueur selon une ligne moyenne et présente une section transversale à cette ligne moyenne dont la forme varie le long de la ligne moyenne de façon à former au moins un premier relief et dans lequel une partie au moins d’un des bords de l’aimant permanent, en regard dudit au moins un des bords de l’encoche, présente au moins un second relief de forme correspondante, en négatif, pour épouser la forme dudit au moins un premier relief. More particularly, according to the invention there is proposed a rotor as defined in the introduction, in which at least one of the edges of the notch extends in length along an average line and has a cross section at this average line of which the shape varies along the mean line so as to form at least a first relief and in which at least part of one of the edges of the permanent magnet, facing said at least one of the edges of the notch, has at least one second relief of corresponding shape, in negative, to match the shape of said at least one first relief.
[0015] Ainsi, grâce à l’invention, la surface de l’aimant permanent collée au corps est augmentée. [0015] Thus, thanks to the invention, the surface area of the permanent magnet adhered to the body is increased.
[0016] Des difficultés d’usinage et de montage pourraient dissuader de façonner des reliefs sur le bord de l’encoche et sur le bord de l’aimant permanent. [0016] Difficulties in machining and assembly could discourage shaping reliefs on the edge of the notch and on the edge of the permanent magnet.
[0017] Cependant, une surface de collage plus grande entre l’aimant permanent et le corps assure un meilleur maintien de l’ensemble et notamment une meilleure résistance aux forces centrifuges. La normale à la surface de collage présentant une direction en outre variable, les contraintes dues aux forces centrifuges sont reparties entre contraintes de traction et contraintes de cisaillement. L’efficacité du collage s’en trouve accrue. La probabilité de détachement des aimants permanents du corps est alors grandement diminuée. However, a larger bonding surface between the permanent magnet and the body ensures better maintenance of the assembly and in particular better resistance to centrifugal forces. The normal to the bonding surface having a direction which is also variable, the stresses due to the centrifugal forces are distributed between tensile stresses and shear stresses. The effectiveness of the bonding is thereby increased. The probability of detachment of the permanent magnets from the body is then greatly reduced.
[0018] De plus, puisque la résistance aux forces centrifuges est augmentée par la surface de collage plus importante, il est possible d’affiner voire de supprimer tout accessoire supplémentaire de maintien des aimants tel que des disques de support enserrant le rotor ou une couche de colle enveloppant le rotor. Cela permet d’une part de réduire le poids du rotor et d’autre part de diminuer la distance de l’entrefer pour maximiser la circulation du flux magnétique. In addition, since the resistance to centrifugal forces is increased by the larger bonding surface, it is possible to refine or even eliminate any additional accessory for maintaining the magnets such as support discs enclosing the rotor or a layer glue wrapped around the rotor. On the one hand, this reduces the weight of the rotor and on the other hand reduces the distance of the air gap to maximize the circulation of the magnetic flux.
[0019] Avantageusement, un interstice est prévu entre ledit au moins un des bords de l’encoche et ledit au moins un des bords de l’aimant permanent, ledit interstice s’étendant sur au moins une partie de la longueur dudit au moins un bord de l’encoche et sur une partie seulement de l’épaisseur dudit corps. Advantageously, a gap is provided between said at least one of the edges of the notch and said at least one of the edges of the permanent magnet, said gap extending over at least part of the length of said at least one edge of the notch and over only part of the thickness of said body.
[0020] Ainsi, l’effet d’une couche de colle ou de vernis enveloppant le rotor est grandement amélioré. L’interstice augmente l’épaisseur de la couche de colle ou de vernis entre le bord de l’encoche et le bord de l’aimant permanent. Cette couche est plus épaisse et donc plus élastique, cela permet de mieux absorber les légers déplacements de l’aimant permanents par rapport au corps liés aux forces centrifuges. [0020] Thus, the effect of a layer of glue or varnish enveloping the rotor is greatly improved. The gap increases the thickness of the layer of glue or varnish between the edge of the notch and the edge of the permanent magnet. This layer is thicker and therefore more elastic, this makes it possible to better absorb the slight movements of the permanent magnet relative to the body due to centrifugal forces.
[0021] Avantageusement, ledit aimant permanent comprend un corps magnétique et une enveloppe qui entoure au moins partiellement le corps magnétique, ledit corps magnétique présente un relief de forme correspondant à celle dudit au moins un second relief. Adapter la forme du corps magnétique à la forme du bord de l’encoche permet de maximiser le volume du corps magnétique par rapport au volume total de l’aimant permanent (et donc par rapport au volume du rotor) et ainsi d’améliorer les performances magnétiques du rotor. Advantageously, said permanent magnet comprises a magnetic body and a casing which at least partially surrounds the magnetic body, said magnetic body has a shape in relief corresponding to that of said at least one second relief. Adapting the shape of the magnetic body to the shape of the edge of the notch makes it possible to maximize the volume of the magnetic body in relation to the total volume of the permanent magnet (and therefore in relation to the volume of the rotor) and thus to improve performance magnets of the rotor.
[0022] Avantageusement, une frette entoure la périphérie de l’ensemble formé par ledit corps et ledit au moins un aimant permanent, et, à l’état démonté, le diamètre interne de la frette est en partie inférieure au diamètre externe dudit ensemble. Advantageously, a hoop surrounds the periphery of the assembly formed by said body and said at least one permanent magnet, and, in the disassembled state, the internal diameter of the hoop is partly less than the external diameter of said assembly.
[0023] Avoir une frette de diamètre en partie inférieure au diamètre de l’ensemble formé du corps et des aimants permanents permet d’assurer un très bon maintien des aimants permanents dans les encoches, ceci tout en facilitant sa mise en place par son extrémité de plus grand diamètre. Avec une telle frette déjà sous contrainte, le maintien des aimants permanents dus aux forces centrifuges est réduit. De plus, cette géométrie de la frette permet d’améliorer la répartition d’une colle, disposée entre la frette et le corps, lors de la mise en place de la frette. Have a diameter hoop partly less than the diameter of the assembly formed of the body and permanent magnets ensures a very good retention of the permanent magnets in the notches, this while facilitating its installation by its end of larger diameter. With such a hoop already under stress, the retention of the permanent magnets due to centrifugal forces is reduced. In addition, this geometry of the hoop makes it possible to improve the distribution of an adhesive, placed between the hoop and the body, during the installation of the hoop.
[0024] D’autres caractéristiques avantageuses et non limitatives du rotor conforme à l’invention, prises individuellement ou selon toutes les combinaisons techniquement possibles, sont les suivantes : [0024] Other advantageous and non-limiting characteristics of the rotor according to the invention, taken individually or in any technically possible combination, are as follows:
-ledit au moins un des bords de l’encoche présente une pluralité de premiers reliefs et ledit au moins un des bords de l’aimant permanent présente une pluralité de seconds reliefs de forme correspondante, en négatif, pour épouser la forme de la pluralité de premiers reliefs ; said at least one of the edges of the notch has a plurality of first reliefs and said at least one of the edges of the permanent magnet has a plurality of second reliefs of corresponding shape, in negative, to match the shape of the plurality of first reliefs;
- ledit au moins un premier relief présente des faces planes ; - Said at least one first relief has flat faces;
- ledit au moins un bord de l’aimant permanent est en contact sur toute sa longueur avec ledit au moins un bord de l’encoche ; - said at least one edge of the permanent magnet is in contact over its entire length with said at least one edge of the notch;
- la normale en tout point de la surface dudit au moins un premier relief est orientée vers l’extérieur de l’encoche ; - the normal at any point of the surface of said at least one first relief is oriented towards the outside of the notch;
- ledit un des bords de l’encoche présente une nervure ou une rainure s’étendant sur au moins une partie de sa longueur et ledit aimant permanent présente respectivement une rainure ou une nervure de forme correspondante (pour préférentiellement former un emboîtement serré) ; et - Said one of the edges of the notch has a rib or a groove extending over at least part of its length and said permanent magnet respectively has a groove or a rib of corresponding shape (to preferably form a tight fit); and
- ladite au moins une encoche s’étend sur toute l’épaisseur dudit corps. - said at least one notch extends over the entire thickness of said body.
[0025] Bien entendu, les différentes caractéristiques, variantes et formes de réalisation de l'invention peuvent être associées les unes avec les autres selon diverses combinaisons dans la mesure où elles ne sont pas incompatibles ou exclusives les unes des autres. Of course, the different characteristics, variants and embodiments of the invention can be associated with each other in various combinations insofar as they are not incompatible or mutually exclusive.
DESCRIPTION DETAILLEE DE L'INVENTION DETAILED DESCRIPTION OF THE INVENTION
[0026] La description qui va suivre en regard des dessins annexés, donnés à titre d’exemples non limitatifs, fera bien comprendre en quoi consiste l’invention et comment elle peut être réalisée. The description which will follow with regard to the accompanying drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be carried out.
[0027] Sur les dessins annexés : In the accompanying drawings:
[0028] La figure 1 est une vue schématique de face d’un rotor de machine électrique. Figure 1 is a schematic front view of a machine rotor electric.
[0029] La figure 2 est une vue schématique en perspective éclatée d’une partie du rotor de la figure 1 représentant un aimant permanent avant son insertion dans une encoche. [0029] Figure 2 is a schematic exploded perspective view of part of the rotor of Figure 1 showing a permanent magnet before it is inserted into a notch.
[0030] La figure 3 est une vue en coupe selon le plan A-A de la figure 2. Figure 3 is a sectional view along the plane A-A of Figure 2.
[0031] La figure 4 est une vue en coupe selon le plan B-B de la figure 2. Figure 4 is a sectional view along the plane B-B of Figure 2.
[0032] La figure 5 est une vue en coupe selon le plan C-C de la figure 1. Figure 5 is a sectional view along the plane C-C of Figure 1.
[0033] La figure 6 est une vue en coupe selon le plan D-D de la figure 1. Figure 6 is a sectional view along the plane D-D of Figure 1.
[0034] La figure 7 illustre schématiquement la figure 6 avant assemblage du rotor. Figure 7 schematically illustrates Figure 6 before assembly of the rotor.
[0035] Sur la figure 1 , on a représenté un rotor 100 de machine électrique. Le rotor 100 comprend un corps 110, une pluralité d’aimant permanent 130 et une frette 150. In Figure 1, there is shown a rotor 100 of an electric machine. The rotor 100 includes a body 110, a plurality of permanent magnets 130, and a hoop 150.
[0036] Le corps 110 a une forme globale de disque, en ce sens qu’il est sensiblement circonscrit à un cylindre de révolution autour d’un axe ci-après appelé axe de rotation A1. Il présente une hauteur (dimension du corps selon l’axe de rotation A1) qui est très inférieure au diamètre. Dans la description qui suit, cette hauteur est appelée épaisseur du corps 110. Le corps 110 possède ainsi deux faces circulaires planes, parallèles entre elles et perpendiculaires à l’axe de rotation A1 du rotor 100, une des deux faces étant visible sur la figure 1. The body 110 has the overall shape of a disc, in the sense that it is substantially circumscribed to a cylinder of revolution about an axis hereinafter called axis of rotation A1. It has a height (dimension of the body along the axis of rotation A1) which is much less than the diameter. In the following description, this height is called the thickness of the body 110. The body 110 thus has two plane circular faces, mutually parallel and perpendicular to the axis of rotation A1 of the rotor 100, one of the two faces being visible in the figure. 1.
[0037] Comme le montre la figure 1 , le corps 110 présente un évidement central adapté à recevoir un arbre de transmission s’étendant le long de l’axe de rotation A1. Le rotor 100 est prévu pour être fixé à cet arbre de transmission qu’il est destiné à entraîner. As shown in Figure 1, the body 110 has a central recess adapted to receive a transmission shaft extending along the axis of rotation A1. The rotor 100 is intended to be fixed to this transmission shaft which it is intended to drive.
[0038] Le corps 110 peut par exemple être réalisé à base d’aluminium, d’acier, de fer, de titane ou en un alliage contenant ces métaux. Il est par exemple réalisé par un empilage de tôles de métal d’une épaisseur inférieure ou égale au millimètre. Ces plaques de tôles sont ici courbes et empilées radialement. Elles s’étendent sur toute la hauteur du corps 101. Ainsi, les pertes dans le stator dues aux courants de Foucault sont limitées. Le corps 110 est de préférence constitué de matière composite renforcée en fibres de verre ou de carbone. [0038] The body 110 can for example be made from aluminum, steel, iron, titanium or an alloy containing these metals. It is for example produced by a stack of metal sheets with a thickness less than or equal to a millimeter. These metal plates are here curved and stacked radially. They extend over the entire height of the body 101. Thus, losses in the stator due to eddy currents are limited. The body 110 is preferably made of a composite material reinforced with glass or carbon fibers.
[0039] Comme le montre la figure 2, le corps est composé de trois couches, deux couches extérieures 112, 114 et une couche centrale 113, ayant des formes globalement identiques. Ces trois couches, empilées selon l’axe de rotation A1 , forment le corps 110. En variante, le corps 110 peut être usiné à partir d’un bloc unique. As shown in Figure 2, the body is composed of three layers, two outer layers 112, 114 and a central layer 113, having generally identical shapes. These three layers, stacked along the axis of rotation A1, form body 110. Alternatively, body 110 may be machined from a single block.
[0040] Comme cela apparaît en figure 1, le corps 110 possède une pluralité d’encoches 120 en creux dans son bord périphérique. Ici, le corps 110 possède douze encoches 120 identiques. Les encoches 120 sont réparties régulièrement sur toute la périphérie du corps 110. Ceci permet d’assurer un bon équilibre du rotor 110 lorsque celui-ci est en rotation. As shown in Figure 1, the body 110 has a plurality of notches 120 recessed in its peripheral edge. Here, the body 110 has twelve identical notches 120. The notches 120 are distributed evenly over the entire periphery of the body 110. This makes it possible to ensure a good balance of the rotor 110 when the latter is rotating.
[0041] En d’autres termes, le corps 110 comprend un moyeu central et une pluralité de branches s’étendant à partir du moyeu selon des directions sensiblement radiales par rapport à l’axe de rotation A1. Telles que représentées sur la figure 1 , les branches s’affinent légèrement en direction de la périphérie du rotor 100. Les branches, au nombre de 12 sur la figure 1 , sont toutes identiques et régulièrement réparties autour du moyeu de façon à être séparées deux à deux par un espace, chaque paire de branches adjacente définit alors une des encoches 120. Ici, ces encoches sont ainsi radialement ouvertes vers l’extérieure, c’est-à-dire vers la périphérie du rotor 100. In other words, the body 110 comprises a central hub and a plurality of branches extending from the hub in substantially radial directions with respect to the axis of rotation A1. As shown in FIG. 1, the branches become thinner towards the periphery of the rotor 100. The branches, 12 in number in FIG. 1, are all identical and regularly distributed around the hub so as to be two separate. two by one space, each pair of adjacent branches then defines one of the notches 120. Here, these notches are thus radially open towards the outside, that is to say towards the periphery of the rotor 100.
[0042] Comme c’est le cas sur la figure 2, chaque encoche 120 s’étend de préférence sur toute l’épaisseur du corps 110. Cela présente l’avantage de fournir deux surfaces de travail opposées. Un tel rotor 100 peut ainsi par exemple être encadré par deux stators pour fournir plus de puissance mécanique. As is the case in Figure 2, each notch 120 preferably extends over the entire thickness of the body 110. This has the advantage of providing two opposing working surfaces. Such a rotor 100 can thus for example be framed by two stators to provide more mechanical power.
[0043] Chaque encoche 120 présente une forme globale de U aux bras écartés, avec deux bords latéraux 121 d’extension sensiblement radiale et un fond ici appelé bord intérieur 122. Each notch 120 has an overall U shape with spaced arms, with two side edges 121 of substantially radial extension and a bottom here called inner edge 122.
[0044] Ici, le bord 122 intérieur est rectiligne (c’est une surface plane). En variante, le bord intérieur 122 peut être courbe, par exemple avec le même rayon de courbure que le corps 110. Here, the inner edge 122 is rectilinear (it is a flat surface). Alternatively, the inner edge 122 may be curved, for example with the same radius of curvature as the body 110.
[0045] Encore en variante l’encoche 120 pourrait présenter une forme en V et posséder uniquement deux bords latéraux, le bord intérieur 122 étant alors assimilé à l’arrête formée par le contact des deux bords latéraux 121. [0045] Still alternatively, the notch 120 could have a V-shape and have only two side edges, the inner edge 122 then being assimilated to the edge formed by the contact of the two side edges 121.
[0046] Ici, chaque encoche 120 a globalement trois bords droits dont deux bords latéraux 121 qui s’écartent l’un de l’autre depuis le centre du corps 110 vers l’extérieur de ce dernier. Cette géométrie permet une insertion radiale simple des aimants permanents 130 dans les encoches 120, par un simple mouvement d’engagement selon une direction radiale A2 (par rapport à l’axe de rotation A1). [0047] Avantageusement, comme le montre la figure 2, les bords latéraux d’une encoche 120 sont pourvus chacun d’une rainure 160 s’étendant en longueur selon une direction sensiblement radiale. Chaque rainure 160 présente une section transversale en U et est délimité entre deux parois latérales 161. Comme le montrent les figures 3 et 4, les parois latérales 161 délimitant ce U sont ici formées par les deux couches 112, 114 extérieures du corps 110. Chaque rainure 160 est ici située à mi-distance des deux faces circulaires du corps 110. Here, each notch 120 generally has three straight edges including two side edges 121 which move away from each other from the center of the body 110 to the outside of the latter. This geometry allows a simple radial insertion of the permanent magnets 130 in the notches 120, by a simple movement of engagement in a radial direction A2 (relative to the axis of rotation A1). Advantageously, as shown in Figure 2, the side edges of a notch 120 are each provided with a groove 160 extending lengthwise in a substantially radial direction. Each groove 160 has a U-shaped cross section and is delimited between two side walls 161. As shown in Figures 3 and 4, the side walls 161 defining this U are here formed by the two outer layers 112, 114 of the body 110. Each groove 160 is here located halfway between the two circular faces of the body 110.
[0048] De plus, le bord intérieur 122 peut présenter un relief, par exemple formé par une différence d’extension radiale des couches extérieures 112, 114 par rapport à la couche centrale 113. Le bord intérieur 122 peut donc présenter une rainure similaire à la rainure 160 d’un bord latéral 121 de l’encoche 120. L’aimant permanent 130 présente alors une forme complémentaire pour s’emboîter dans ce relief. In addition, the inner edge 122 may have a relief, for example formed by a difference in radial extension of the outer layers 112, 114 relative to the central layer 113. The inner edge 122 may therefore have a groove similar to the groove 160 of a side edge 121 of the notch 120. The permanent magnet 130 then has a complementary shape to fit into this relief.
[0049] Chaque rainure 160 est conçue de façon à s’emboîter avec une nervure 170 prévue en correspondance sur l’aimant permanent 130, en saillie de ses bords latéraux. Cet assemblage de type rainure et nervure assure une résistance élevée du rotor 100 par rapport aux efforts axiaux que subissent les aimants permanents 130 lorsque que le moteur électrique est en fonctionnement et que les aimants permanents 130 sont attirés vers les bobines du stator. Each groove 160 is designed to interlock with a rib 170 provided in correspondence with the permanent magnet 130, projecting from its side edges. This groove and rib type assembly ensures a high resistance of the rotor 100 with respect to the axial forces undergone by the permanent magnets 130 when the electric motor is in operation and the permanent magnets 130 are attracted towards the coils of the stator.
[0050] En variante, on pourrait prévoir que chaque nervure s’étende en saillie du bord latéral de l’encoche et que chaque rainure s’étende en creux dans l’un des bords latéraux de l’aimant permanent 130. [0050] Alternatively, one could provide that each rib protrudes from the side edge of the notch and that each groove extends recessed into one of the side edges of the permanent magnet 130.
[0051] Chaque bord latéral 121 de l’encoche 120 s’étend en longueur (ici dans une direction orthogonale à l’axe de rotation A1) selon une ligne moyenne D1. Ici, la ligne moyenne D1 est une droite. En variante, la ligne moyenne pourrait être une courbe. Each side edge 121 of the notch 120 extends in length (here in a direction orthogonal to the axis of rotation A1) along a mean line D1. Here, the mean line D1 is a straight line. Alternatively, the mean line could be a curve.
[0052] On définit ici la ligne moyenne D1 comme la ligne passant en moyenne au plus près des centres géométriques des surfaces formées par les sections du bord latéral (le plan de section considéré étant orthogonal au rayon selon lequel s’étend sensiblement ce bord). Ainsi, la ligne moyenne peut par exemple être définie comme une droite de régression linéaire sur les positions des centres géométriques des surfaces formées par les sections du bord latéral. The mean line D1 is defined here as the line passing on average as close as possible to the geometric centers of the surfaces formed by the sections of the lateral edge (the section plane considered being orthogonal to the radius along which this edge extends substantially) . Thus, the mean line can for example be defined as a linear regression line on the positions of the geometric centers of the surfaces formed by the sections of the lateral edge.
[0053] Chaque aimant permanent 130 a une forme adaptée à l’encoche 120 dans laquelle il est inséré. Comme le montrent les figures 1 et 2, chaque aimant permanent 130 a donc ici une forme globalement trapézoïdale. Chaque aimant permanent 130 a une épaisseur (dimension selon l’axe de rotation A1) sensiblement égale à l’épaisseur du corps 110. Each permanent magnet 130 has a shape adapted to the notch 120 in which it is inserted. As shown in Figures 1 and 2, each magnet permanent 130 here therefore has a generally trapezoidal shape. Each permanent magnet 130 has a thickness (dimension along the axis of rotation A1) substantially equal to the thickness of the body 110.
[0054] Chaque aimant permanent 130 possède ainsi deux bords d’aimant 131 situés en regard des bords latéraux 121 de l’encoche 120 dans laquelle il est inséré. Les bords d’aimant 131 ont une géométrie quasi-identique, en négatif, à la géométrie des bords latéraux 121. Les bords d’aimant 131 sont notamment pourvus d’une nervure 170 s’emboîtant, à un jeu de montage près, dans la rainure 160. Each permanent magnet 130 thus has two magnet edges 131 located opposite the side edges 121 of the notch 120 in which it is inserted. The edges of the magnet 131 have an almost identical geometry, in negative, to the geometry of the side edges 121. The edges of the magnet 131 are in particular provided with a rib 170 which fits together, except for an assembly clearance, in the groove 160.
[0055] Selon l’invention, l’un au moins des bords latéraux 121 de chaque encoche 120, s’étendant en longueur selon la ligne moyenne D1 qui lui est associée, présente une section transversale à cette ligne moyenne dont la forme varie le long de la ligne moyenne de façon à former au moins un premier relief 140, et au moins une partie du bord d’aimant 131 au contact du bord latéral 121 présente un second relief 141 de forme correspondante, en négatif, pour épouser la forme du premier relief 140. According to the invention, at least one of the side edges 121 of each notch 120, extending in length along the mean line D1 associated with it, has a cross section to this mean line, the shape of which varies from along the middle line so as to form at least a first relief 140, and at least part of the edge of the magnet 131 in contact with the lateral edge 121 has a second relief 141 of corresponding shape, in negative, to match the shape of the first relief 140.
[0056] Ici, les deux bords latéraux des encoches 120 sont identiques. Here, the two side edges of the notches 120 are identical.
[0057] Sur la figure 3, on a représenté un premier plan de coupe A-A du bord latéral 121 de la figure 2 qui représente une première section transversale au niveau d’un premier relief 140. Sur la figure 4, on a représenté un deuxième plan de coupe B-B du bord latéral 121 de la figure 2 qui représente une deuxième section transversale dans une zone dépourvue de premier relief 140. In Figure 3, there is shown a first section plane AA of the side edge 121 of Figure 2 which shows a first cross section at a first relief 140. In Figure 4, there is shown a second section plane BB of the side edge 121 of FIG. 2 which represents a second transverse section in a zone devoid of a first relief 140.
[0058] Comme le montre les figures 3 et 4, la forme de la section transversale à la ligne moyenne D1 varie le long de la ligne moyenne D1 entre les deux plans de coupe A-A et B-B. Ici, puisque les premiers reliefs 140 sont en saillie du bord latéral 121 , les parois latérales 161 délimitant la rainure 160 sont plus hautes pour la première section transversale que pour la deuxième section transversale. En d’autres termes la rainure 160 est plus profonde au niveau d’un premier relief 140 que dans une zone dépourvue de premier relief 140. As shown in Figures 3 and 4, the shape of the cross section to the mean line D1 varies along the mean line D1 between the two section planes A-A and B-B. Here, since the first reliefs 140 project from the side edge 121, the side walls 161 defining the groove 160 are higher for the first cross section than for the second cross section. In other words, the groove 160 is deeper at a first relief 140 than in an area without a first relief 140.
[0059] Ici, la forme de la section transversale à la ligne moyenne D1 est une forme en U dont la profondeur varie linéairement par section le long de la ligne moyenne D1 entre une profondeur minimum et une profondeur maximum. Here, the shape of the cross section at the mean line D1 is a U shape, the depth of which varies linearly by section along the mean line D1 between a minimum depth and a maximum depth.
[0060] Les reliefs 140, 141 augmentent la surface de contact entre l’aimant permanent 130 et le corps 110, plus précisément entre le bord latéral 121 de l’encoche 120 et le bord d’aimant 131. The reliefs 140, 141 increase the contact surface between the permanent magnet 130 and the body 110, more precisely between the side edge 121 of notch 120 and magnet edge 131.
[0061] Ici, comme le montre la figure 6, une couche de colle 190 est disposée entre l’aimant permanent 130 et le corps 110 au niveau de l’encoche 120 (sur le corps 110 et/ou sur l’aimant permanent 130). Cette couche de colle 190 a pour but d’assurer le maintien de l’aimant permanent 130 dans l’encoche 120 lorsque le rotor 100 est en rotation et que l’aimant permanent 130 est soumis à des forces centrifuges importantes (d’autant plus importantes que la vitesse de rotation est élevée). Here, as shown in Figure 6, a layer of glue 190 is disposed between the permanent magnet 130 and the body 110 at the notch 120 (on the body 110 and / or on the permanent magnet 130 ). The purpose of this layer of glue 190 is to ensure that the permanent magnet 130 is held in the notch 120 when the rotor 100 is rotating and the permanent magnet 130 is subjected to significant centrifugal forces (all the more as the rotation speed is high).
[0062] Par conséquent, augmenter la surface de contact permet d’augmenter la surface de collage, ce qui assure un meilleur maintien de l’aimant permanent 130 dans l’encoche 120. [0062] Therefore, increasing the contact surface increases the bonding surface, which ensures better retention of the permanent magnet 130 in the notch 120.
[0063] De plus, grâce à l’invention, les directions normales à la surface de contact, c’est-à-dire à la surface de collage, sont variées. Cela permet de mieux répartir les contraintes que subie la couche de colle entre contraintes en traction et contraintes en cisaillement lorsque le rotor 100 est en rotation. [0063] In addition, thanks to the invention, the directions normal to the contact surface, that is to say to the bonding surface, are varied. This makes it possible to better distribute the stresses to which the adhesive layer is subjected between tensile stresses and shear stresses when the rotor 100 is rotating.
[0064] Dans la direction axiale, ici selon l’axe de rotation A1 , l’aimant permanent 130 est principalement retenu par les rainures 160 latérales. Réaliser le corps 110 dans un matériau résistant, par exemple en matériau composite renforcée en fibres de verre ou de carbone, permet un maintient axial efficace de l’aimant permanent 130. In the axial direction, here along the axis of rotation A1, the permanent magnet 130 is mainly retained by the lateral grooves 160. Making the body 110 in a resistant material, for example a composite material reinforced with glass or carbon fibers, allows effective axial retention of the permanent magnet 130.
[0065] Avantageusement, chaque bord latéral 121 possède une pluralité de premiers reliefs 140 et chaque bord d’aimant 131 possède une pluralité de seconds reliefs 141 correspondants. La surface de collage est ainsi encore augmentée ce qui accroît le maintien de l’aimant permanent 130 dans l’encoche 120. Advantageously, each side edge 121 has a plurality of first reliefs 140 and each magnet edge 131 has a plurality of corresponding second reliefs 141. The bonding surface is thus further increased which increases the retention of the permanent magnet 130 in the notch 120.
[0066] Comme le montre la figure 2, chaque bord latéral 121 possède cinq premiers reliefs 140 sur chacune des deux parois latérales 161 délimitant la rainure 160. Ici, les premiers reliefs 140 donnent aux faces d’extrémités des parois latérales 161 de la rainure 160 une forme en zigzag ou en dents de scie qui est constituée de lignes brisées. As shown in Figure 2, each side edge 121 has five first reliefs 140 on each of the two side walls 161 defining the groove 160. Here, the first reliefs 140 give the end faces of the side walls 161 of the groove 160 a zigzag or sawtooth shape which consists of broken lines.
[0067] Par correspondance, chaque bord d’aimant 131 possède dix seconds reliefs 141 : cinq de chaque côté de la nervure 170. [0067] By correspondence, each edge of the magnet 131 has ten second reliefs 141: five on each side of the rib 170.
[0068] Ici, les premiers reliefs 140 sont des reliefs en saillies des faces d’extrémités des parois latérales 161 de la rainure 160 et les seconds reliefs 141 sont des renfoncements dans le bord d’aimant 131. Here, the first reliefs 140 are reliefs projecting from the end faces of the side walls 161 of the groove 160 and the second reliefs 141 are recesses in the magnet edge 131.
[0069] En variante, les premiers reliefs 140 situés sur les bords latéraux 121 des encoches 120 (plus précisément sur les parois latérales 161 des rainures 160) pourraient être des renfoncements et les seconds reliefs 141 pourraient être en saillies du bord d’aimant 131. On peut également prévoir que les premiers reliefs 141 comprennent à la fois des reliefs en saillie et des renfoncements et que les seconds reliefs 141 comprennent des renfoncements et des reliefs en saillie correspondants. As a variant, the first reliefs 140 located on the side edges 121 of the notches 120 (more precisely on the side walls 161 of the grooves 160) could be recesses and the second reliefs 141 could protrude from the edge of the magnet 131 Provision can also be made for the first reliefs 141 to include both projecting reliefs and recesses and for the second reliefs 141 to include corresponding recesses and projecting reliefs.
[0070] On pourrait aussi prévoir que les premiers reliefs soient situés dans le fond de la rainure et que les seconds reliefs soient situés sur la nervure. Provision could also be made for the first reliefs to be located in the bottom of the groove and for the second reliefs to be located on the rib.
[0071] De façon préférentielle, chaque premier relief 140 présente des faces planes. Cela implique que les seconds reliefs 141 correspondants présentent également des faces planes. Sur la figure 2, chaque premier relief 140 possède deux faces d’extrémité rectangulaires reliées ensemble par une arrête et deux faces latérales triangulaires (ici des triangles isocèles). Preferably, each first relief 140 has flat faces. This implies that the corresponding second reliefs 141 also have flat faces. In Figure 2, each first relief 140 has two rectangular end faces connected together by a ridge and two triangular side faces (here isosceles triangles).
[0072] Utiliser des faces planes pour les reliefs 140, 141 présente des facilités d’usinage. Using flat faces for the reliefs 140, 141 presents machining facilities.
[0073] De préférence, le bord d’aimant 131 est en contact sur toute sa longueur avec le bord latéral 121 de l’encoche 120. Ainsi, la surface de contact entre l’aimant permanent 130 et l’encoche 120 est maximum. Preferably, the magnet edge 131 is in contact along its entire length with the side edge 121 of the notch 120. Thus, the contact area between the permanent magnet 130 and the notch 120 is maximum.
[0074] Le fait que le bord d’aimant 131 permanent soit en contact sur toute sa longueur avec le bord latéral 121 de l’encoche 120 signifie que le bord latéral 121 possède une unique surface de contact contiguë avec le bord d’aimant 131 qui lui est associé, cette surface contiguë s’étendant du bord intérieur 122 à la périphérie du corps 110. On peut alors qualifier l’emboitement de complet. The fact that the permanent magnet edge 131 is in contact over its entire length with the side edge 121 of the notch 120 means that the side edge 121 has a single contact surface contiguous with the magnet edge 131 which is associated with it, this contiguous surface extending from the inner edge 122 to the periphery of the body 110. The interlocking can then be qualified as complete.
[0075] Pour pouvoir assembler le rotor, chaque premier relief 140 est orienté de manière à ce que l’aimant permanent 130 puisse être engagé dans l’encoche 120 selon une direction radiale A2. In order to be able to assemble the rotor, each first relief 140 is oriented so that the permanent magnet 130 can be engaged in the notch 120 in a radial direction A2.
[0076] Selon une caractéristique avantageuse de l’invention, la surface de chaque premier relief 141 est toujours orientée vers l’extérieur de l’encoche 120 (vers la périphérie), par opposition au bord intérieur 122. La surface de chaque premier relief 141 n’est ainsi jamais orientée vers le bord intérieur 122. Dans un cas limite, la surface de chaque premier relief 141 est orthogonale avec la surface du bord intérieur 122. [0077] Comme cela est représenté sur la figure 1 , les surfaces de chaque premier relief 141 sont orientées vers l’extérieur de l’encoche 120. Par extérieur de l’encoche on entend également, à l’extrême limite, une orientation selon une direction perpendiculaire à la direction radiale A2. According to an advantageous characteristic of the invention, the surface of each first relief 141 is always oriented towards the outside of the notch 120 (towards the periphery), as opposed to the inner edge 122. The surface of each first relief 141 is thus never oriented towards the interior edge 122. In a limiting case, the surface of each first relief 141 is orthogonal with the surface of the interior edge 122. As shown in Figure 1, the surfaces of each first relief 141 are oriented towards the outside of the notch 120. By outside of the notch is also meant, at the extreme limit, an orientation according to a direction perpendicular to the radial direction A2.
[0078] Ici, comme le montre la figure 6, lorsque le rotor 100 est assemblé, un interstice 143 est localisé sur au moins une partie de la longueur de chaque bord latéral 121 , entre le corps 110 et l’aimant permanent 130. Cet interstice s’étend sur une partie seulement de l’épaisseur du corps 110. Here, as shown in Figure 6, when the rotor 100 is assembled, a gap 143 is located over at least part of the length of each side edge 121, between the body 110 and the permanent magnet 130. This interstice extends over only part of the thickness of body 110.
[0079] Pour former cet interstice 143, on peut prévoir par exemple, que la hauteur de la nervure 170 prévues en saillie de chaque bord d’aimant 131 soit légèrement plus grande que la profondeur de la rainure 160 correspondante. Ainsi, les premiers 140 et seconds 141 reliefs se font face à une faible distance. [0080] Classiquement, une fois le rotor 100 assemblé, celui-ci est vernis avec une couche de colle externe qui enveloppe le rotor 100. La couche de colle externe peut être déposée sous forme d’aérosol par pulvérisation ou encore par immersion du rotor 100 dans un bain de colle liquide. To form this gap 143, provision can be made, for example, for the height of the rib 170 provided to project from each edge of the magnet 131 to be slightly greater than the depth of the corresponding groove 160. Thus, the first 140 and second 141 reliefs face each other at a short distance. Conventionally, once the rotor 100 has been assembled, the latter is varnished with an outer layer of glue which envelops the rotor 100. The outer glue layer can be deposited in the form of an aerosol by spraying or else by immersion of the rotor. 100 in a bath of liquid glue.
[0081] Lors de cette étape, la couche de colle externe va donc s’infiltrer dans la l’interstice 143. L’interstice 143 augmente l’épaisseur de la couche de colle entre le bord latéral 121 et l’aimant permanent 130 (c’est-à-dire entre le bord latéral 121 et le bord d’aimant 131). La couche de colle est plus épaisse et donc plus élastique. Cela permet de mieux absorber les légers déplacements de l’aimant permanent 130 par rapport au corps 110 lorsqu’il subit des forces centrifuges. La colle peut légèrement se déformer sans se fissurer ou rompre. During this step, the outer layer of adhesive will therefore infiltrate into the gap 143. The gap 143 increases the thickness of the layer of adhesive between the side edge 121 and the permanent magnet 130 ( that is, between the side edge 121 and the magnet edge 131). The glue layer is thicker and therefore more elastic. This makes it possible to better absorb the slight movements of the permanent magnet 130 relative to the body 110 when it is subjected to centrifugal forces. The glue may warp slightly without cracking or breaking.
[0082] Pour renforcer encore plus la fixation de l’aimant permanent 130 dans l’encoche 120 on peut prévoir de disposer une couche de colle entre le bord intérieur 122 et le bord interne 132 de l’aimant permanent 130. To further strengthen the attachment of the permanent magnet 130 in the notch 120, it is possible to provide a layer of adhesive between the inner edge 122 and the inner edge 132 of the permanent magnet 130.
[0083] Toutes les caractéristiques avantageuses de l’invention présentées ci- dessus assurent un meilleur maintien des aimants permanents 130 dans le corps 110. Il est donc possible d’affiner la couche de colle externe. On peut aussi prévoir de ne pas utiliser de disque de support (de tels disques supports sont généralement utilisés pour prendre le rotor en sandwich afin de le consolider). Cela a pour effet d’une part d’alléger le rotor 100 et d’autre part de réduire la distance de l’entrefer (entre le rotor 100 et le stator) et donc d’augmenter les performances du moteur. [0084] Comme le montre les figures 1 et 2, en plus des deux bords d’aimant 131 , chaque aimant permanent 130 possède un bord interne 132 plan et un bord externe 180. All the advantageous characteristics of the invention presented above ensure better retention of the permanent magnets 130 in the body 110. It is therefore possible to refine the external adhesive layer. It is also possible not to use a support disc (such support discs are generally used to sandwich the rotor in order to consolidate it). This has the effect on the one hand of lightening the rotor 100 and on the other hand of reducing the distance of the air gap (between the rotor 100 and the stator) and therefore of increasing the performance of the motor. As shown in Figures 1 and 2, in addition to the two magnet edges 131, each permanent magnet 130 has a plane inner edge 132 and an outer edge 180.
[0085] Le bord interne 132 s’applique contre le bord intérieur 122 de l’encoche 120. Le bord externe 180 affleure la périphérie du corps 110. Le bord externe 180 est courbe et possède le même rayon de courbure que le corps 110. Ainsi, la surface périphérique du rotor 110 est cylindrique. The inner edge 132 is applied against the inner edge 122 of the notch 120. The outer edge 180 is flush with the periphery of the body 110. The outer edge 180 is curved and has the same radius of curvature as the body 110. Thus, the peripheral surface of the rotor 110 is cylindrical.
[0086] Chaque aimant permanent 130 possède une enveloppe 135 et un corps magnétique 136. Each permanent magnet 130 has a casing 135 and a magnetic body 136.
[0087] Le corps magnétique 136 est la partie de l’aimant permanent 130 qui génère un champ magnétique statique. Il peut par exemple être composé d’un assemblage néodyme fer bore ou samarium cobalt. [0087] The magnetic body 136 is the part of the permanent magnet 130 which generates a static magnetic field. It can for example be composed of a neodymium iron boron or samarium cobalt assembly.
[0088] Ici, chaque corps magnétique 136 est composé d’une pluralité d’aimants unitaires dont la longueur s’étend sur toute l’épaisseur de l’aimant permanent 130 et dont la section est hexagonale. Utiliser une pluralité d’aimants unitaires permet de réduire les pertes par courants de Focault par rapport à un aimant unique de même taille. En variante, les aimants unitaires pourraient avoir une section différente, par exemple carrée, triangulaire ou ronde. Here, each magnetic body 136 is composed of a plurality of unit magnets whose length extends over the entire thickness of the permanent magnet 130 and whose section is hexagonal. Using a plurality of individual magnets reduces Focault current losses compared to a single magnet of the same size. As a variant, the unit magnets could have a different section, for example square, triangular or round.
[0089] L’enveloppe 135 entoure le corps magnétique 136 au niveau des bords de l’encoche 120 et de la périphérie du corps 110. L’enveloppe 135 ne recouvre pas le corps magnétique 136 au niveau de ses faces principales. L’enveloppe 135 est de préférence réalisée dans un matériau amagnétique. L’enveloppe 135 peut être réalisée en plastique ou en résine, par exemple une résine époxy. [0089] The envelope 135 surrounds the magnetic body 136 at the edges of the notch 120 and the periphery of the body 110. The envelope 135 does not cover the magnetic body 136 at its main faces. The envelope 135 is preferably made of a non-magnetic material. The envelope 135 can be made of plastic or resin, for example an epoxy resin.
[0090] Comme le montrent les figures 1 et 2, les seconds reliefs 141 sont formés par l’enveloppe 135. Toutefois, le corps magnétique 136 présente préférentiellement des reliefs (au niveau des bords d’aimant 131) de formes correspondant aux seconds reliefs 141. Ici, de la même façon que le bord latéral 121 de chaque encoche 120, le corps magnétique 136 de chaque aimant permanent 130 présente un profil en dents de scie. Lorsqu’un second relief 141 forme un renfoncement dans l’enveloppe 135, le corps magnétique 136 présente également un renfoncement au niveau de ce second relief 141. Suivre au plus près la forme des seconds reliefs 141 permet de maximiser le volume du corps magnétique 136 par rapport à l’aimant permanent 130. Cette adaptation du corps magnétique 136 aux seconds reliefs 141 peut être réalisée en agençant les aimants unitaires en fonction de la forme de l’encoche 120. As shown in Figures 1 and 2, the second reliefs 141 are formed by the envelope 135. However, the magnetic body 136 preferably has reliefs (at the edges of the magnet 131) of shapes corresponding to the second reliefs 141. Here, like the side edge 121 of each notch 120, the magnetic body 136 of each permanent magnet 130 has a sawtooth profile. When a second relief 141 forms a recess in the casing 135, the magnetic body 136 also has a recess at the level of this second relief 141. Closely following the shape of the second relief 141 makes it possible to maximize the volume of the magnetic body 136 relative to the permanent magnet 130. This adaptation of the magnetic body 136 to the second reliefs 141 can be achieved by arranging the individual magnets according to the shape of the notch 120.
[0091] La frette 150 du rotor, représentée sur la figure 1 , entoure la périphérie du corps 110 et les aimants permanents 130 par leurs bords extérieurs 180. Le rôle de la frette 150 est de fournir un moyen de maintien supplémentaire (contre les forces centrifuges) pour les aimants permanent 130 lorsque le rotor 100 est en rotation. La frette 150 est réalisée en matériaux composites telles que des fibres de verre, de carbone ou des fibres polymères noyées dans une résine. The rotor hoop 150, shown in Figure 1, surrounds the periphery of the body 110 and the permanent magnets 130 by their outer edges 180. The role of the hoop 150 is to provide an additional holding means (against the forces centrifugal) for the permanent magnets 130 when the rotor 100 is rotating. The hoop 150 is made of composite materials such as glass fibers, carbon fibers or polymer fibers embedded in a resin.
[0092] La frette 150 a une forme annulaire. The hoop 150 has an annular shape.
[0093] Avantageusement, à l’état démonté, le diamètre interne de la frette 150 est strictement inférieur au diamètre externe du corps 110. Advantageously, in the disassembled state, the internal diameter of the hoop 150 is strictly less than the external diameter of the body 110.
[0094] Lors de sa mise en place, la frette 150 subit alors une légère déformation élastique. Ainsi, la frette 150 est précontrainte et apporte plus de maintien aux aimants permanents 130. When it is put in place, the hoop 150 then undergoes a slight elastic deformation. Thus, the hoop 150 is preloaded and provides more support to the permanent magnets 130.
[0095] On pourrait prévoir que le bord extérieur de chaque aimant permanent s’étende selon une surface cylindrique de révolution. Provision could be made for the outer edge of each permanent magnet to extend along a cylindrical surface of revolution.
[0096] Toutefois, ici, comme le montrent les figures 2 et 5, le bord extérieur 180 de chaque aimant permanent 130 présente une forme différente, avec ici trois faces. Une première face 181 s’étend selon une surface cylindrique de révolution autour de l’axe de rotation A1 , dans le prolongement de la périphérie du corps 110 tandis qu’une seconde face 183 s’étend selon une surface cylindrique de révolution de diamètre plus grand. Une troisième face 182, qui permet de relier les deux autres faces entre elles, s’étend selon une surface tronconique de révolution autour de l’axe de rotation A1. However, here, as shown in Figures 2 and 5, the outer edge 180 of each permanent magnet 130 has a different shape, with three faces here. A first face 181 extends along a cylindrical surface of revolution around the axis of rotation A1, in the extension of the periphery of the body 110 while a second face 183 extends along a cylindrical surface of revolution of diameter more big. A third face 182, which connects the other two faces together, extends along a frustoconical surface of revolution around the axis of rotation A1.
[0097] La frette 150 présente une surface interne adaptée à celle des bords extérieurs 180 des aimants. Ici, la surface intérieure de la frette 150 présente donc également trois faces. The hoop 150 has an internal surface adapted to that of the external edges 180 of the magnets. Here, the inner surface of the hoop 150 therefore also has three faces.
[0098] En variante, on peut prévoir que le bord extérieur de chaque aimant permanent présente une seule surface tronconique de révolution autour de l’axe de rotation. La surface interne de la frette est alors une surface tronconique correspondante. Dans ce cas, en coupe axiale, le profil de la frette a alors une forme de trapèze rectangle. As a variant, provision can be made for the outer edge of each permanent magnet to have a single frustoconical surface of revolution around the axis of rotation. The internal surface of the hoop is then a corresponding frustoconical surface. In this case, in axial section, the profile of the hoop then has the shape of a rectangular trapezoid.
[0099] La face de la frette 150 de plus grand diamètre a un diamètre égal, à un jeu près, au diamètre externe du corps 110 et des premières faces 181 des bords extérieurs 180 des aimants permanents 130. La frette 150 peut ainsi être mise en place par ce côté du corps 110. La frette 150 se déforme ensuite au fur et à mesure de son insertion car les autres faces de la surface intérieure de la frette 150 ont des diamètres inférieurs au diamètre externe du corps 110. The face of the hoop 150 of larger diameter has a diameter equal, except for a clearance, to the outer diameter of the body 110 and the first faces 181 of the outer edges 180 of the permanent magnets 130. The hoop 150 can thus be put in placed by this side of the body 110. The hoop 150 then deforms as it is inserted because the other faces of the inner surface of the hoop 150 have diameters smaller than the outer diameter of the body 110.
[0100] La frette 150 est elle-aussi collée au corps 110 et aux aimants permanents 130. Grâce à cette frette 150 qui, à l’état démonté, a un diamètre interne en partie inférieur au diamètre externe du corps 110, on peut disposer une faible quantité colle qui se répartie lors de la mise en place de la frette 150. [0100] The hoop 150 is itself also glued to the body 110 and to the permanent magnets 130. Thanks to this hoop 150 which, in the disassembled state, has an internal diameter partly smaller than the external diameter of the body 110, it is possible to have a small amount of glue which is distributed during the installation of the hoop 150.
[0101] La figure 6 illustre le rotor 100, selon le plan de coupe D-D de la figure 1 , une fois l’aimant permanent 130 inséré dans l’encoche 120 et une fois la frette 150 mise en place. Une première couche de colle 190 est répartie entre l’encoche 120 et l’aimant permanent 130. Ici, la première couche de colle 190 est notamment répartie dans l’interstice 143 entre le bord d’encoche 121 et l’aimant permanent 130. Une deuxième couche de colle 191 est répartie entre l’aimant permanent 130 et la frette 150. [0101] Figure 6 illustrates the rotor 100, along the section plane D-D of Figure 1, once the permanent magnet 130 has been inserted into the notch 120 and once the band 150 in place. A first layer of glue 190 is distributed between the notch 120 and the permanent magnet 130. Here, the first layer of glue 190 is in particular distributed in the gap 143 between the notch edge 121 and the permanent magnet 130. A second layer of adhesive 191 is distributed between the permanent magnet 130 and the hoop 150.
[0102] La figure 7 illustre, toujours selon le plan de coupe D-D de la figure 1 , le rotor 100 avant que l’aimant permanent 130 soit inséré dans l’encoche 120 et avant que la frette 150 soit mise en place. La première couche de colle 190 est répartie dans la rainure 160. La deuxième couche de colle 191 est répartie au niveau de la troisième face 182 du bord extérieur 180 de l’aimant permanent 130. [0103] Ici le rotor 110 est assemblé par une insertion radiale de l’aimant permanent 130 dans l’encoche 120. La frette 150 peut être mise en place dans un même temps ou dans un second temps. [0102] Figure 7 illustrates, still along the sectional plane D-D of Figure 1, the rotor 100 before the permanent magnet 130 is inserted into the notch 120 and before the band 150 is in place. The first layer of glue 190 is distributed in the groove 160. The second layer of glue 191 is distributed at the level of the third face 182 of the outer edge 180 of the permanent magnet 130. [0103] Here the rotor 110 is assembled by a radial insertion of the permanent magnet 130 in the notch 120. The hoop 150 can be put in place at the same time or subsequently.
[0104] Lors de sa mise en place, la frette 150 effectue une translation selon la direction de l’axe de rotation A1. La mise en place de la frette 150 permet ici de répartir la deuxième couche de colle 190 le long du bord extérieur 180. Comme le montre la figure 7, les dimensions internes de la frette 150 font que sa mise en place permette aussi de contraindre l’aimant permanent 130 en direction de l’encoche 120. Cette contrainte permet ou facilite l’insertion de la nervure 170 dans la rainure 160. Lors de l’insertion de la nervure 170 dans la rainure 160, la première couche de colle 190 se répartie le long du bord d’encoche 121. [0104] When it is put in place, the hoop 150 translates in the direction of the axis of rotation A1. The establishment of the hoop 150 here makes it possible to distribute the second layer of glue 190 along the outer edge 180. As shown in FIG. 7, the internal dimensions of the hoop 150 mean that its installation also makes it possible to constrain l 'permanent magnet 130 in the direction of the notch 120. This constraint allows or facilitates the insertion of the rib 170 in the groove 160. When inserting the rib 170 in the groove 160, the first layer of adhesive 190 is formed. distributed along the edge of notch 121.
[0105] En variante, on peut prévoir de disposer initialement la première couche de colle sur la nervure et la deuxième couche de colle sur la frette. As a variant, provision can be made to initially place the first layer of adhesive on the rib and the second layer of adhesive on the hoop.
[0106] Une fois la frette 150 mise en place, comme décrit précédemment, un vernis ou une couche de colle externe enveloppant le rotor 100 peut être déposé. Cela peut permettre de combler des espaces, entre l’encoche 120 et l’aimant permanent 130 et entre l’aimant permanent 130 et la frette 150, où la première couche de colle 190 et respectivement la deuxième couche de colle 191 ne se seraient pas réparties. En particulier, cela peut permettre de remplir de colle l’interstice 143. Once the hoop 150 has been put in place, as described above, a varnish or an external layer of glue enveloping the rotor 100 can be deposited. This can make it possible to fill in the spaces, between the notch 120 and the permanent magnet 130 and between the permanent magnet 130 and the hoop 150, where the first layer of glue 190 and respectively the second layer of glue 191 would not have come together. distributed. In particular, this can make it possible to fill the gap 143 with glue.
[0107] Dans ce mode d’assemblage, la forme et l’orientation des premiers reliefs 140 et des seconds reliefs 141 permettent un emboîtement complet des aimants permanents 130 dans les encoches 120. En variante, les aimants permanents 130 peuvent être, dans une première étape, insérés dans la couche centrale 113 du corps 110. Ici, suite à cette première étape, les nervures 170 bordants les aimants permanents 130 se trouvent en contact avec le fond des rainures 160 prévues dans les encoches 120. Dans une seconde étape, les couches extérieures 112, 114 du corps 110 sont plaquées de part et d’autre de la couche centrale 113. Ici, les premiers reliefs 140 sont réalisés dans ces couches extérieures 112, 114 du corps 110 et s’insèrent dans les seconds reliefs 141 réalisés dans l’enveloppe 135 des aimants permanents 130. In this method of assembly, the shape and orientation of the first reliefs 140 and of the second reliefs 141 allow complete engagement of the permanent magnets 130 in the notches 120. As a variant, the permanent magnets 130 may be, in one first step, inserted into the central layer 113 of the body 110. Here, following this first step, the ribs 170 bordering the permanent magnets 130 are in contact with the bottom of the grooves 160 provided in the notches 120. In a second step, the outer layers 112, 114 of the body 110 are plated on either side of the central layer 113. Here, the first reliefs 140 are made in these outer layers 112, 114 of the body 110 and are inserted into the second reliefs 141 made in the envelope 135 of the permanent magnets 130.
[0108] Dans cette variante du mode d’assemblage, la forme et l’orientation des premiers et seconds reliefs 140, 141 n’est pas contrainte par l’insertion radiale des aimants permanent 130. D’autres variantes de forme pour les premiers reliefs 141 sont envisageables, par exemples des formes bloquant une sortie radiale des aimants permanents 130 lorsque le rotor 100 est en rotation. In this variant of the assembly method, the shape and orientation of the first and second reliefs 140, 141 is not constrained by the radial insertion of the permanent magnets 130. Other shape variants for the first reliefs 141 are conceivable, for example shapes blocking a radial exit of the permanent magnets 130 when the rotor 100 is rotating.

Claims

REVENDICATIONS
[Revendication 1] Rotor (100) pour machine électromagnétique à flux axial comprenant : [Claim 1] Rotor (100) for an axial flow electromagnetic machine comprising:
- un corps (110) en forme globale de disque, avec un bord périphérique présentant au moins une encoche (120) délimitée par au moins deux bords (121), et - a body (110) in the overall form of a disc, with a peripheral edge having at least one notch (120) delimited by at least two edges (121), and
- au moins un aimant permanent (130) qui est situé dans ladite encoche (120) et qui présente au moins deux bords (131) respectivement en regard des au moins deux bords (121) de l’encoche (120), au moins un des bords (121) de l’encoche (120) s’étendant en longueur selon une ligne moyenne (D1) et présentant une section transversale à cette ligne moyenne dont la forme varie le long de la ligne moyenne (D1) de façon à former au moins un premier relief (140), une partie au moins d’un des bords (131) de l’aimant permanent (130), en regard dudit au moins un des bords (121) de l’encoche (120), présentant au moins un second relief (141) de forme correspondante, en négatif, pour épouser la forme dudit au moins un premier relief (140), caractérisé en ce ladite encoche (120) s’étend en creux dans le bord périphérique dudit corps (110). - at least one permanent magnet (130) which is located in said notch (120) and which has at least two edges (131) respectively facing the at least two edges (121) of the notch (120), at least one edges (121) of the notch (120) extending in length along a mean line (D1) and having a cross section to this mean line, the shape of which varies along the mean line (D1) so as to form at least a first relief (140), at least part of one of the edges (131) of the permanent magnet (130), facing said at least one of the edges (121) of the notch (120), having at least one second relief (141) of corresponding shape, in negative, to match the shape of said at least one first relief (140), characterized in that said notch (120) extends recessed in the peripheral edge of said body (110 ).
[Revendication 2] Rotor (100) selon la revendication 1 , dans lequel ledit au moins un des bords (121) de l’encoche (120) présente une pluralité de premiers reliefs (140) et dans lequel ledit au moins un des bords (131) de l’aimant permanent (130) présente une pluralité de seconds reliefs (141) de forme correspondante, en négatif, pour épouser la forme de la pluralité de premiers reliefs (140). [Claim 2] A rotor (100) according to claim 1, wherein said at least one of the edges (121) of the notch (120) has a plurality of first reliefs (140) and wherein said at least one of the edges ( 131) of the permanent magnet (130) has a plurality of second reliefs (141) of corresponding shape, in negative, to match the shape of the plurality of first reliefs (140).
[Revendication 3] Rotor (100) selon l’une des revendications 1 à 2, dans lequel ledit au moins un premier relief (140) présente des faces planes. [Claim 3] A rotor (100) according to one of claims 1 to 2, wherein said at least one first relief (140) has planar faces.
[Revendication 4] Rotor (100) selon l’une des revendications 1 à 3, dans lequel ledit au moins un des bords (131) de l’aimant permanent (130) est en contact sur toute sa longueur avec ledit au moins un des bords (121) de l’encoche (120). [Claim 4] A rotor (100) according to one of claims 1 to 3, wherein said at least one of the edges (131) of the permanent magnet (130) is in contact along its entire length with said at least one of the edges. edges (121) of the notch (120).
[Revendication 5] Rotor (100) selon l’une des revendications 1 à 4, dans lequel la normale en tout point de la surface dudit au moins un premier relief (140) est orientée vers l’extérieur de l’encoche (120). [Claim 5] A rotor (100) according to one of claims 1 to 4, wherein the normal at any point of the surface of said at least one first relief (140) is oriented outwardly of the notch (120) .
[Revendication 6] Rotor (100) selon l’une des revendications 1 à 5, dans lequel ledit au moins un aimant permanent (130) comprend un corps magnétique (136) et une enveloppe (135) qui entoure au moins partiellement le corps magnétique (136), ledit corps magnétique (136) présente un relief de forme correspondant à celle dudit au moins un second relief (141). [Claim 6] A rotor (100) according to one of claims 1 to 5, wherein said at least one permanent magnet (130) comprises a magnetic body (136) and a casing (135) which at least partially surrounds the magnetic body. (136), said magnetic body (136) has a relief of shape corresponding to that of said at least one second relief (141).
[Revendication 7] Rotor (100) selon l’une des revendications 1 à 6, dans lequel ledit au moins un des bords (121) de l’encoche (120) présente une rainure (160) ou une nervure s’étendant sur au moins une partie de sa longueur et ledit au moins un aimant permanent (130) présente respectivement une nervure (170) ou une rainure de forme correspondante. [Claim 7] A rotor (100) according to one of claims 1 to 6, wherein said at least one of the edges (121) of the notch (120) has a groove (160) or a rib extending over the at least part of its length and said at least one permanent magnet (130) respectively has a rib (170) or a groove of corresponding shape.
[Revendication 8] Rotor (100) selon l’une des revendications 1 à 7, dans lequel un interstice (143) est prévu entre ledit au moins un des bords (121) de l’encoche (120) et ledit au moins un des bords (131) de l’aimant permanent (130), ledit interstice (143) s’étendant sur au moins une partie de la longueur dudit au moins un des bords (121) de l’encoche (120) et sur une partie seulement de l’épaisseur dudit corps (110). [Claim 8] A rotor (100) according to one of claims 1 to 7, wherein a gap (143) is provided between said at least one of the edges (121) of the notch (120) and said at least one of the notch (120). edges (131) of the permanent magnet (130), said gap (143) extending over at least a portion of the length of said at least one of the edges (121) of the notch (120) and over only a portion the thickness of said body (110).
[Revendication 9] Rotor (100) selon l’une des revendications 1 à 8, dans lequel ladite au moins une encoche (120) s’étend sur toute l’épaisseur dudit corps (110). [Claim 9] A rotor (100) according to one of claims 1 to 8, wherein said at least one notch (120) extends through the entire thickness of said body (110).
[Revendication 10] Rotor (100) selon l’une des revendications 1 à 9, comprenant une frette (150) qui entoure la périphérie de l’ensemble formé par ledit corps (110) et ledit au moins un aimant permanent (130), et dans lequel, à l’état démonté, le diamètre interne de la frette (150) est en partie inférieur au diamètre externe dudit ensemble. [Claim 10] A rotor (100) according to one of claims 1 to 9, comprising a hoop (150) which surrounds the periphery of the assembly formed by said body (110) and said at least one permanent magnet (130), and wherein, in the disassembled state, the internal diameter of the hoop (150) is in part smaller than the external diameter of said assembly.
EP21709023.2A 2020-03-06 2021-03-05 Rotor for an axial flux electromagnetic machine Pending EP4115498A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR2002258A FR3107999B1 (en) 2020-03-06 2020-03-06 Rotor for axial flux electromagnetic machine
PCT/EP2021/055594 WO2021176058A1 (en) 2020-03-06 2021-03-05 Rotor for an axial flux electromagnetic machine

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EP4115498A1 true EP4115498A1 (en) 2023-01-11

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EP (1) EP4115498A1 (en)
KR (1) KR20220157987A (en)
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Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
PT1203436E (en) * 1999-08-09 2003-09-30 Perm Motor Gmbh AXIAL FLOW MACHINE
GB0800225D0 (en) 2008-01-07 2008-02-13 Evo Electric Ltd A rotor for an electrical machine
JP2011130530A (en) * 2009-12-15 2011-06-30 Honda Motor Co Ltd Axial gap motor and manufacturing method of rotor of the same
DE202012012228U1 (en) * 2012-12-20 2013-02-01 Klaus-Dieter Nies Rotor for a machine shaft of an electric axial flux machine
FR3004025B1 (en) * 2013-03-29 2015-03-27 Renault Sa DISCOID ROTOR FOR AN AXIAL FLUX ELECTRIC MOTOR
FR3006124B1 (en) * 2013-05-23 2015-05-29 Renault Sa AXIAL FLUX ELECTRIC MACHINE ROTOR AND CORRESPONDING ELECTRIC MACHINE
FR3027468B1 (en) * 2014-10-21 2019-05-24 Renault S.A.S DISCOID ROTOR WITH COMPOSITE STRUCTURE
JP6700596B2 (en) * 2016-06-21 2020-05-27 株式会社デンソー Rotor for axial gap motor and axial gap motor
FR3083023B1 (en) * 2018-06-22 2021-12-03 Whylot Sas ROTOR FOR ELECTROMAGNETIC MOTOR OR GENERATOR WITH TAPERED BRANCHES
CN109639003A (en) * 2019-01-24 2019-04-16 三门峡速达交通节能科技股份有限公司 Rotor, disc type electric machine and the vehicle of disc type electric machine
CN110620449B (en) * 2019-08-19 2021-03-16 山东大学 Disc type transverse flux permanent magnet brushless motor and method
CN110707845A (en) * 2019-09-18 2020-01-17 广州通达汽车电气股份有限公司 Rotor structure and motor

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CN115210994A (en) 2022-10-18
KR20220157987A (en) 2022-11-29
WO2021176058A1 (en) 2021-09-10
FR3107999B1 (en) 2023-06-23
FR3107999A1 (en) 2021-09-10

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