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
  • H02K1/12—Stationary parts of the magnetic circuit
  • H02K1/17—Stator cores with permanent magnets
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K13/00—Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings; Disposition of current collectors in motors or generators; Arrangements for improving commutation
  • H02K13/10—Arrangements of brushes or commutators specially adapted for improving commutation
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K23/00—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors
  • H02K23/02—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting
  • H02K23/04—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting having permanent magnet excitation
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
  • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
  • H02K15/02—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies
  • H02K15/03—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines of stator or rotor bodies having permanent magnets

Definitions

• Rotating electric machine particularly for a motor vehicle starter
• the present invention relates in particular to a rotating electrical machine, in particular for a motor vehicle starter.
• EP-B1 -985 334 discloses a starter comprising a stator provided with a plurality of magnetic poles disposed on an inner circumferential surface of a cylinder head. Each magnetic pole is formed by a permanent ferrite magnet magnetized so that the north and south poles appear radially. Auxiliary magnets may be provided between the aforementioned magnets. These auxiliary magnets are made of ferrite and magnetized so that the north and south poles appear circumferentially. Space is provided between each auxiliary magnet and the cylinder head. Such an arrangement reduces magnetic leakage.
• One of the aims of the invention is to reduce the effects of the armature magnetic reaction.
• Another object of the invention is to facilitate the attachment of magnets in a starter stator.
• the object of the invention is, according to one of its aspects, a rotating electric machine with direct current, in particular for a starter of a motor vehicle, the machine comprising: a stator, or inductor, comprising a magnetized structure with permanent magnetization, extending along a circumference of the stator,
• the machine being characterized in that the magnetized structure of the stator comprises at least one sector having a magnetization of direction different from radial and orthoradial directions of the stator.
• the invention as defined above allows in particular to achieve the magnetized structure with two or more angular transitions between two consecutive magnetic poles of the machine.
• the magnetization direction can vary in a relatively progressive way when one moves on the circumference of the magnetized structure.
• the applicant has unexpectedly found that such a magnetized structure can increase the torque and the mass power of the machine, as well as reduce or even substantially cancel the displacement of the magnetic neutral line when the armature current increases. , and thus substantially cancel the effects.
• the magnetic neutral line is defined as the place where the induction vanishes between two consecutive poles of the inductor.
• the invention may also make it possible to improve the switching and to limit the wear of the brushes and the vibro-acoustic radiation of the machine.
• the angular transitions further enhance the mechanical stability of permanent magnets of the magnetized structure.
• Attallah et al and Marinescu et al describe a magnetization with several angular transitions between the magnetic poles, their teaching is limited to the case of machines in which the variation of induction with respect to the electric angle is ideally sinusoidal. .
• the variation of the induction with respect to the electrical angle must be close to a trapezoidal shape with a large plate, so that the induction is maximum on a angular range as wide as possible.
• the sector with a magnetization direction different from radial and orthoradial directions extends over an electrical angle greater than 10 °, in particular 20 °, or even 30 ° or 40 °.
• the electric angle corresponds to an angle actually measured within the machine, also called the mechanical angle, multiplied by the number of pairs of poles of the machine, which amounts to considering any machine as a juxtaposition within the same set of several elementary machines to a single pair of poles.
• the direction of magnetization in the magnetization sector of direction different from radial and orthoradial directions, forms with the orthoradial direction of the stator an angle of, for example, between 5 ° and 85 °, in particular between 10 ° and 80 °, or between 20 ° and 70 ° or between 30 ° and 60 °.
• the magnetization within the magnetized structure has a non-parallel direction to itself when moving on a tower of the stator.
• the direction of magnetization within the magnetized structure varies without angular jump greater than 90 °, in particular without angular jump greater than or equal to 45 °, when moves on the circumference of the stator.
• the magnetized structure of the stator can be arranged against a yoke and have a magnetization chosen so that the magnetic field generated by the magnetic structure outside thereof, and measured in the absence of the yoke, is more weak that the generated field inside the magnetized structure, the magnetic energy outside the magnetized structure being in particular less than 30% or 20% of the magnetic energy inside the structure, the magnetic energy outside the structure, measured in the absence of the yoke, being notably substantially zero.
• the angle between the direction of magnetization of the structure and a radial direction of the stator varies monotonously, that is to say this angle varies in increasing or decreasing manner. when moving from a magnetic pole to a next pole.
• the magnetized structure of the stator comprises a plurality of permanent magnets, at least one of the magnets having, in a central region following a circumference of the stator, a magnetization of direction of magnetization different from radial and orthoradial directions.
• the magnetized structure of the stator may comprise a plurality of permanent magnets, at least one of the permanent magnets having at all points a magnetization of magnetization direction different from radial and orthoradial directions.
• this permanent magnet has a direction of magnetization which is substantially parallel to itself at any point of the magnet.
• the magnetized structure of the stator comprises at least two permanent magnets defining two consecutive magnetic poles of the magnetized structure and this structure further comprises two permanent magnets interposed between said two magnets defining the poles.
• the magnetized structure may have, if appropriate, a thickness, measured in a radial direction of the magnetized structure, substantially constant when moving circumferentially from a magnetic pole of the structure to a next pole.
• the magnetized structure may have a thickness that varies as one travels circumferentially from a magnetic pole of the structure to a next pole.
• the magnetized structure may for example comprise permanent magnets of different thicknesses.
• the magnetized structure is devoid of interrupted zone having an electric angle opening greater than 1 °, in particular 2 ° or 5 °.
• the interrupted zone corresponds for example to the presence of a tab of a support of the magnetized structure inserted in a radial slot of this structure.
• This tongue defines an air gap between two permanent magnets of the magnetized structure.
• the orientation of the magnetization direction within the magnetized structure varies between two poles. consecutive magnetic circuits, substantially discontinuously or, alternatively, continuously.
• the machine according to the invention can be of the type two or four poles, or preferably six poles or more.
• the magnetized structure may comprise a number of permanent magnets strictly greater than the number of poles of the machine, in particular greater than or equal to twice the number of poles.
• the machine can be of the six-pole type and the magnetized structure comprise 24 permanent magnets.
• the magnetized structure comprises a number of permanent magnets less than or equal to the number of poles of the machine, being in particular equal to half the number of poles.
• the machine may be six-pole type and the magnetized structure have three permanent magnets each extending at an angle of about 120 °.
• the magnetized structure comprises at least one permanent magnet made of NdFeB, especially sintered.
• the magnetized structure comprises at least one magnet made of ferrite.
• the subject of the invention is also a rotating electric machine with direct current, in particular for a starter of a motor vehicle, the machine comprising:
• stator comprising a magnetized structure with permanent magnetization, extending along a circumference of the stator
• the machine being characterized in that the magnetic structure of the stator comprises at least one sector, between two consecutive magnetic poles of this structure, having a magnetization vector varying substantially sinusoidally when moving on the circumference of the stator.
• the sinusoidal shape of the magnetization makes it possible to obtain a lower sensitivity to the armature reaction and to increase, if necessary, the torque developed by the machine.
• the angular offset of the neutral line is chosen so as to improve the switching during operation of the machine, by actively accelerating the current in the rotor during inversion.
• the realization of the angular offset can be better controlled, particularly with respect to the case of a radial direction magnetization, because this angular offset is performed along a substantially linear or locally linear induction law
• the angular offset of the neutral line may in particular be greater than 15 ° electrical or 20 ° electrical.
• the magnetization vector within the magnetized structure may, if desired, vary substantially sinusoidally over the entire circumference of this structure.
• the magnetized structure comprises at least one sector having a magnetization vector that varies in a non-sinusoidal manner, for example with a radial direction in the sector, this sector extending in particular at an electrical angle greater than 10 °, in particular 20 °.
• the machine forms a starter motor vehicle with a strong armature reaction.
• the electric machine may comprise a gearbox.
• the invention makes it possible, thanks to a gain in torque, to reduce the rotational speed of the commutator of the machine, for the same operating point of the torque, which ensures a longer time for switching and consequently a reduction in losses and electrical arcing (sparking) of brushes and collector.
• the invention also relates, independently or in combination with the foregoing, to a rotating electrical machine, particularly for a motor vehicle starter, of the N magnetic pole type (N being an integer), comprising a stator, or inductor, comprising:
• a plurality of permanent magnets the number of magnets being in particular strictly greater than the number N of poles of the machine, at least one support integrally carrying the permanent magnets.
• the invention may make it possible to dispose permanent magnets on the support substantially adjacent two by two. Permanent magnets can be in contact two by two, with no space between them. Alternatively, a small gap, or gap, is formed between two consecutive magnets.
• the support is arranged to maintain the permanent magnets at at least one of their axial ends, for example at their two opposite axial ends.
• the support comprises a plurality of tabs arranged to hold the magnets at at least one of their axial ends.
• At least one of the legs of the support can in particular be folded, for example by folding, on the permanent magnet to ensure the maintenance thereof.
• the support is made in one piece.
• the support comprises at least two separate parts, at least one of which is arranged at one of the axial ends of the permanent magnets.
• the support can, if desired, be deformable, in particular to be wound, and arranged to allow the establishment of magnets on the support flat, before winding thereof.
• the support comprises, for example, a plurality of parallel branches extending in particular perpendicularly to a circumference of the support, each branch having at its two opposite ends lugs for holding the permanent magnets. These legs do not have to be folded on the magnets to ensure their maintenance.
• the support may comprise hinge portions having a reduced width. These hinge portions facilitate the winding of the support once the magnets placed on the support.
• This support may have cutouts leaving the outer surface of the magnets partially uncovered.
• the support is preformed so as to have an annular or cylindrical shape before the establishment of permanent magnets.
• the support may comprise a plurality of tongues, each interposed between two consecutive permanent magnets, to hold them correctly both radially and angularly. A small air gap is then formed between two consecutive magnets.
• the support is made for example at least partially of sheet metal, for example by folding the sheet.
• the support may for example be formed by a metal strip folded flat to give it an annular shape. This way of making it possible to avoid losses of material for example following a cutting.
• the support can be made by cutting and stamping a sheet.
• this cylindrical wall can serve as a shell for the passage of the magnetic flux and allow to reduce, if necessary, the thickness of the cylinder head.
• At least one of the permanent magnets has an orthoradial direction magnetization. At least one of the magnets may have a direction magnetization different from the radial and orthoradial directions of the stator.
• the support carries a plurality of radial magnetization direction main magnets and a plurality of auxiliary magnets each disposed between two consecutive main magnets, and having an orthoradial magnetization direction.
• Auxiliary magnets may for example have a thickness measured in a radial direction of the stator which is lower than that of the main magnets.
• These auxiliary magnets are for example separated from the cylinder head by a space corresponding substantially to the difference in thickness between main magnets and auxiliary magnets.
• the invention also relates to a method for manufacturing a rotating electrical machine as defined above, comprising the steps of setting up a plurality of permanent magnets on a common support and then bringing the assembly thus formed against a cylinder head of the stator.
• the method may optionally comprise the steps of first winding the support and then put in place the permanent magnets on the wound support.
• the method may include the steps of placing the permanent magnets on the support flat and then winding the support.
• the support comprises magnets holding tabs
• these tabs can be folded on the magnets after placing them on the support.
• the legs of the support are folded before introduction of permanent magnets on the support, these magnets being for example fixed by snapping on the support elastically deforming the tabs.
• the fixing of the support in the stator yoke is carried out for example by buttoning. Any other way of attaching the bracket to the cylinder head can be used.
• the invention also relates, independently or in combination with the foregoing, to a rotating electrical machine comprising a stator comprising at least one permanent magnet and at least one support of the permanent magnet, the machine being characterized in that the support of the magnet comprises at least one lug and the magnet comprises at least one recessed or raised fixing portion arranged to cooperate with the bracket lug when the magnet is placed on the support.
• the legs of the support make it possible in particular to maintain the magnets radially on this support and, where appropriate, in a circumferential direction as well.
• the embodiment on the magnet of a recessed mounting portion allows in particular to receive the support leg, which can avoid the undesired presence of radial protuberances that prevent the correct mounting of the rotor in the stator.
• the electric machine comprises a rotor, and said at least one permanent magnet has inner and outer faces, the inner face facing the rotor, the fixing portion of the magnet being in particular carried out, in particular entirely, on one of the inner and outer faces of the magnet.
• the permanent magnet comprises recessed or raised fixing portions on both the inner and outer faces.
• the attachment portion is formed, if desired, by a notch on one side of the magnet.
• the notch opens for example on an axial edge of the magnet.
• This notch may have a substantially rectangular shape.
• the notch may have any other shape, for example substantially trapezoidal or arcuate.
• the bracket of the bracket has a shape substantially matching that of the notch, the tab being in particular substantially rectangular.
• the fixing portion comprises a bead protruding from one side of the magnet and the bracket lug may be arranged to cooperate with this bead to maintain the magnet on the support.
• recessed or raised fixing portions are formed on one side only of the magnet, in particular an inner face. At least one of the magnets may comprise, if desired, a notch made on an axial portion of the magnet.
• the magnet is made by sintering, the fixing portion of the magnet being derived from the sintering.
• the tab of the support is for example folded against the recessed portion or in relief of the magnet, this support being in particular made by folding a metal sheet.
• the electric machine according to the invention can be arranged to operate at a maximum power of between 500 W and 2000 W, for example.
• FIG. 1 shows, schematically and partially, a motor vehicle starter according to an exemplary implementation of the invention
• FIGS. 4a and 4b are two graphs representing the variation of the vector potential as a function of the angle in the gap, respectively according to the invention and the state of the art,
• FIG. 5 illustrates, schematically and partially, another example of a magnetized structure according to the invention
• FIG. 6 represents, schematically and partially, a permanent magnet according to an exemplary implementation of the invention
• FIG. 7 schematically and partially shows a support for magnets according to FIG. 6;
• FIGS. 8 and 9 illustrate, schematically and partially, the placement of the support of FIG. 7 with the permanent magnets in a cylinder head; stator, two stages of assembly,
• FIG. 10 represents, schematically and partially, a stator according to another example of implementation of the invention
• FIG. 11 is a schematic partial view, in perspective, of a permanent magnet according to another exemplary embodiment. implementation of the invention
• FIG. 12 represents, schematically and partially, a support for magnets according to FIG. 11,
• FIG. 13 illustrates, schematically and partially, the support of FIG. 12 with the permanent magnets fixed on it
• FIG. 14 represents, schematically and partially, a stator according to another example of implementation of the invention.
• FIG. 15 is a diagrammatic and partial view, in perspective, of a support according to an exemplary implementation of the invention, flat before winding,
• FIG. 16 represents, schematically and partially, a permanent magnet according to an exemplary implementation of the invention, to be arranged on the support of FIG.
• FIG. 17 illustrates, schematically and partially, the support of FIG. 15, after winding
• FIG. 18 represents, schematically and partially, a support with permanent magnets placed on it, in accordance with another example of implementation of the invention.
• FIG. 19 illustrates, schematically and partially, a stator according to another example of implementation of the invention
• FIG. 20 represents, schematically and partially, a permanent magnet to be disposed in the stator of FIG. 19,
• FIG. 21 illustrates, schematically and partially, the forces exerted on a permanent magnet of the stator of FIG. 19;
• FIGS. 22 and 23 show, schematically and partially, two other examples of magnets with notches,
• FIG. 24 illustrates the sinusoidal magnetization within a magnetized structure according to another example of implementation of the invention
• FIG. 25 schematically represents the variation of the induction as a function of the angle, generated by a known magnetized structure
• FIG. 26 diagrammatically represents the variation of the induction as a function of the angle, generated by the magnetic magnetization structure illustrated in FIG. 24, and
• FIGS. 27 and 28 illustrate two types of angular offset of the neutral line, for the magnetic magnetization structure illustrated in FIG. 24.
• FIG. 1 shows very schematically a starter 1 for a motor vehicle combustion engine.
• This DC starter 1 comprises, on the one hand, a rotor 2, also called an armature, rotatable about an axis X, and on the other hand, a stator 3, also called an inductor, around the rotor 2.
• This stator 3 comprises a yoke 4 carrying a magnetized structure 5 with permanent magnetization.
• the rotor 2 comprises a rotor body 7 and a coil 8 wound in notches of the rotor body 7.
• the rotating electric machine formed by the starter 1 is of the six-pole type.
• the winding 8 forms, on either side of the rotor body 7, a front bun 9 and a rear bun 10.
• the rotor 2 is provided, at the rear, with a collector 12 comprising a plurality of contact pieces electrically connected to the conductive elements, formed in the example in question by wires, of the winding 8.
• a group of brushes 13 and 14 is provided for the electrical supply of the winding 8, one of the brushes 13 being connected to the ground of the starter 1 and another of the brushes 14 being connected to an electrical terminal 15 of a contactor 17 via a wire 16.
• the brushes are for example four in number. The brushes 13 and 14 rub against the collector 12 when the rotor 2 is rotating, allowing the rotor 2 to be powered by switching the electric current in sections of the rotor 2.
• the starter 1 further comprises a launcher assembly 19 slidably mounted on a drive shaft 18 and drivable in rotation about the X axis by the rotor 2.
• a gear reduction unit 20 is interposed between the rotor 2 and the drive shaft 18, in a manner known per se.
• the starter 1 may be of the 'Direct Drive' type, without a gearbox.
• the launcher assembly 19 comprises a drive element formed by a pulley 21 and intended to engage on a drive member of the combustion engine, not shown. This drive member is for example a belt.
• the pulley 21 may be replaced by a gear element, in particular a gear wheel, for driving the combustion engine.
• the launcher assembly 19 further comprises a freewheel 22 and a pulley washer 23 defining between them a groove 24 for receiving the end 25 of a fork 27.
• This fork 27 is made for example by molding a plastic material.
• the fork 27 is actuated by the switch 17 to move the launcher assembly 19 relative to the drive shaft 18, along the X axis, between a first position in which the launcher assembly 19 drives the combustion engine by through the pulley 21, and a second position in which the launcher assembly 19 is disengaged from the combustion engine.
• the switch 17 comprises, in addition to the terminal 15 connected to the brush 14, a terminal 29 connected via an electrical connection element, in particular a wire 30, to a power supply of the vehicle, in particular a battery.
• FIG. 2 shows an example of a magnetized structure 5 according to a first embodiment of the invention.
• the magnetized structure 5 comprises a number of permanent magnets, this number being equal to 24, strictly greater than the number of poles of the machine, which is equal to six.
• Six of the 24 magnets have a radial direction magnetization, parallel to the arrow F1 illustrated in FIG.
• These magnets 40a define the six poles of the machine, including three North N poles and three South poles S opposite the interior of the stator.
• the direction of magnetization is substantially uniform within each magnet 40c and forms with the radial direction F1 an angle A1 of about 45 °.
• the magnets 40c thus each define a sector of the magnetized structure 5 having a direction of magnetization different from radial and orthoradial directions and having an angular aperture A2 of 15 °, which corresponds to an electric angle of 45 °.
• the magnets 40c have at all points, in particular in a central region along the circumference F3 of the stator 3, a direction of magnetization different from F1 radial and orthoradial directions F2.
• the permanent magnets 40a-40c may have, as illustrated in FIG. 2, identical dimensions, so that the magnetized structure 5 has a thickness, measured in the radial direction F1, substantially constant when moving on the circumference F3.
• the magnetization direction of the magnetized structure 5 has four angular breaks, each of 45 °.
• the magnetization then has a number of angular transitions, between two poles N and S, equal to three.
• the angle between the direction of magnetization of the structure and the radial direction F1 varies in a monotonous and discontinuous manner, without angular recoil. This can make it possible to concentrate the magnetic energy towards the air gap, between the rotor 2 and the stator 3, corresponding to a significant reduction in the induction outside the magnetized structure 5 and a significant increase in the induction to inside.
• the magnetic field generated by the magnetized structure outside thereof, and measured in the absence of the yoke 4 is smaller than the field generated inside the magnetized structure 5, the magnetic energy outside the magnetic structure being in particular less than 30% or 20% of the magnetic energy inside the structure, the magnetic energy outside the structure, measured in the absence of the breech, being especially negligible.
• FIG. 4a shows the variations of the potential-vector (units: Wb / m) as a function of the angle in the gap, for several values of the current I and a number of angular transitions equal to two. These variations were obtained by finite element analysis.
• the graph of FIG. 4a is in the form of a conventional two-dimensional representation making it easy to show any shift in the magnetic neutral line.
• Note in Figure 4a a virtual absence of displacement of the magnetic neutral line, which corresponds to the place where the induction is canceled between two consecutive poles, when the current I varies.
• the permanent magnets 40a-40c are anisotropic sintered ferrite magnets.
• the magnetization of the magnets 40a-40c is carried out for example outside the cylinder head 4.
• the permanent magnets 40a-40c may contain rare earth elements, being for example made of NdFeB.
• the magnetized structure 5 comprises a number of permanent magnets 40a-40c greater than the number of poles N and S of the machine.
• the structure 5 may include a number of permanent magnets less than the number of poles of the machine.
• the structure 5 comprises three permanent magnets 41 each substantially having a cylindrical shape of a cylinder of revolution of angle A3 equal to 120 °.
• magnets 41 are for example made of NdFeB, with isotropic properties and having a sinusoidally varying directional magnetization when moving on the circumference F2 of the stator 3, along a magnet 41. If desired, it is possible to magnetize the magnets 41 inside the cylinder head 4.
• the number of angular transitions between two consecutive poles of the machine remains equal to three.
• the number of angular transitions is different from three.
• This number may, depending on the type of machine, be equal to two or greater than or equal to four.
• Figure 5 a magnetized structure 5 having six angular transitions between two consecutive magnetic poles.
• the number of poles may be different from six, especially being greater than six.
• the machine may comprise for example 8 poles.
• the machine may have a number of poles less than six, for example 2 or 4 poles.
• a number of poles less than six, for example 2 or 4 poles.
• FIGS. 6 to 9 illustrate different elements of a stator 50 according to an exemplary implementation of the invention, for example to equip the starter 1.
• a support 51 and a plurality of permanent magnets 52 intended to be mounted on the support 51.
• the support 51 comprises a cylindrical wall 53 of axis X of circular cross section.
• This wall 53 has two opposite end edges 54, on each of which are connected a plurality of tabs 55 projecting towards the inside of the wall 53.
• Each tab 55 arranged regularly on the corresponding edge 54 are 24 on each end of the wall 51 so as to allow the establishment of 24 permanent magnets 52.
• Each tab 55 comprises a first leg 57 perpendicular to the X axis extended by a second end branch 58 perpendicular to the first.
• the support 51 is further provided with fasteners 59 arranged to allow fixing the support 51 on an inner surface 60 of a cylinder head 61 by buttoning.
• Any other suitable means for fixing the support 51 on the cylinder head 61 may be used.
• the support 51 can be made for example by rolling a metal sheet.
• This sheet may be made of magnetic material, for example steel.
• Each permanent magnet 52 has inner 63 and outer 64 faces, as can be seen in Figure 6.
• These faces 63 and 64 are defined by cylinder portions of revolution so that when all the magnets 52 are placed on the support 51 the faces 62 and 64 of the set of magnets form two substantially cylindrical concentric surfaces.
• Each magnet 52 further comprises two lateral faces 65 converging towards the center of the support 51.
• Recessed fixing portions 67 are formed on each face 63 of the permanent magnets 52 in order to allow these magnets to be held on the support 51 by means of the tabs 55.
• each fixing portion 67 is formed by a notch opening on an axial edge 69 of the magnet 52.
• the notch 67 has a substantially rectangular shape. Alternatively, the notch may have any other suitable shape.
• the dimensions and shape of the notches 67 are selected so as to fit the leg 58 of the tabs 55 when the magnets 52 are placed on the support 51.
• each leg 58 engages in a notch 67 of a magnet 52 and each leg 57 is applied against an axial end of the magnet 52.
• the magnets 52 are then held in the radial and circumferential directions, as illustrated in FIG. 8.
• magnets 52 are placed on the support 51 by snapping, namely by elastic deformation of the tabs 55.
• the tabs 55 can be folded by folding on the magnets
• the depth of the notches 67 is substantially equal to the thickness of the legs 58 of the tabs 55 so that these branches 58 do not project into the gap of the electric machine.
• the magnets 52 are made in particular by sintering, and the notches 67 are derived from this sintering. Alternatively, these notches 67 can be made by removal of material.
• the solid cylindrical wall 53 can serve as a shell inside the cylinder head 61 to reduce the magnetic saturation and to reduce, if necessary, the thickness of the cylinder head 61.
• the magnets 52 are placed on the support 51 in contact two by two. Thus, it avoids the presence of gap between lateral faces 65 of the magnets 52.
• the number of permanent magnets 52 may be different from 24, depending on the needs.
• the stator may comprise 8 permanent magnets 52 fixed on a support 51 provided with 8 pairs of legs 55.
• each magnet then having larger dimensions it may be advantageous to maintain each magnet using more legs 55.
• each magnet 55 can be held by four legs.
• the permanent magnets have notches. It is not beyond the scope of the present invention when one places on the support one or more permanent magnets devoid of a portion of recessed or raised fixing, in particular without notches 67 as described above.
• FIG. 11 to 13 illustrates such an example of implementation of the invention, in which a plurality of identical permanent magnets 70, with no hollow or raised fixing portion, of which there are 24 in each case. described example, are placed on a support 71.
• Each magnet 70 has radially inner 74 and outer 75 faces substantially in concentric cylinder portions, as well as lateral faces 76 converging radially inwardly.
• the support 71 is initially flat to allow the establishment of permanent magnets 70, as shown in Figure 12.
• This support 71 comprises a plurality of branches 78 parallel to the axis X each having at opposite ends tabs 79 for holding the magnets 70.
• the tabs 79 extend perpendicular to the corresponding branch 78 and each have a substantially rectangular shape.
• the support 71 is further provided with a plurality of tongues 80, perpendicular to the branches 78, each tab being interposed between two consecutive magnets 70, so as to maintain these magnets angularly and radially.
• the magnetized structure formed by the magnets 70 is advantageously devoid of interrupted zone, corresponding to the gap, having an electric angle opening greater than 1 °, in particular 2 ° or 5 °.
• the number, the dimensions and the shape of the tabs 80 are chosen in particular according to the magnets 70 to be maintained.
• the support 71 has portions 82 forming a hinge of reduced width and to facilitate the winding of the support 71 once the magnets 70 placed on it.
• the portions 82 are alternated with the branches 78.
• the support 71 is for example made by cutting and folding a strip of metal sheet. This support 71 has cutouts 83 leaving the outer face 75 of the magnets 70 partially uncovered.
• Arms 85 are provided at one end of the support 71 to maintain the latter in the wound state.
• These arms 85 are for example engaged in notches 86 made on tabs 79 at an opposite end of the support 71.
• the support 71 can be arranged to be maintained in the wound state only by its implementation in the cylinder head.
• the example which has just been described may, without departing from the scope of the invention, be adapted to a number of magnets less than 24, for example 12, 8, 6, 4, 3 or 2.
• FIGS. 14 to 16 show different elements of a stator 90 according to an exemplary implementation of the invention, comprising a support 91 formed by two separate pieces 92.
• Each piece 92 is made from a sheet metal strip folded flat to give this piece 92 an annular shape, as shown in FIG. 17.
• parts 92 may be made of other materials.
• the outside diameter of the parts 91 is equal to the inside diameter of the cylinder head 94 in which the support 91 with permanent magnets 95 is put in place.
• Each piece 92 comprises a plurality of tabs 97 for holding magnets 95. These tabs 97 have, for example, a substantially rectangular shape.
• tabs 97 extend radially and each interpose between two adjacent magnets 95 disposed on a circumference of the corresponding part 92. Other tabs 97 extend substantially along the circumference of the piece 92, facing two by two, to hold the magnets 95 in a radial direction.
• the magnets 95 each comprise two pairs of notches 99 of substantially rectangular shape, arranged to receive the tabs 97 of the parts 92 when the magnets 95 are mounted on the parts 92, these being then disposed at the opposite ends of the magnets 95.
• Two of the notches 99 are located on an outer face 100 of the magnet and the two other notches 99 on an inner face 101. These notches 99 open on end edges 102 of the magnet 95.
• the magnets 95 are of two types.
• a first group 95a of magnets are called main magnets, which have a radial direction magnetization so as to define alternating north and south poles.
• a second group 95b of magnets 95 define auxiliary magnets, each being disposed between two main magnets, these auxiliary magnets having a substantially orthoradial directional magnetization.
• the auxiliary magnets may have the same thickness, measured in the radial direction, as that of the main magnets.
• the auxiliary magnets may have a thickness different from that of the main lovers. It is possible to position the auxiliary magnets so as to provide a space between these magnets and the cylinder head 94. In other words the auxiliary magnets are not pressed against this cylinder head 94.
• the spacing between the auxiliary magnets and the cylinder head is advantageously determined by the positioning of the tabs 97 which hold these magnets.
• the magnets 95 may be arranged to have two or more angular transitions, as described above.
• the parts 92 further include tabs 103 for securing these parts 92 to the cylinder head 94 by buttoning. Other suitable means of securing the support 91 may be used.
• the parts 92 of the support 91 and the magnets 95 can form an independent assembly before fitting into the cylinder head 94, which can simplify assembly operations.
• the electric machine has six poles. Possibly the tabs 97 which extend radially can be removed, and the rotation of the magnets 95 is maintained by the cooperation of the tabs 97 circumferential with the notches 99 of the magnets 95.
• the parts 92 are made by cutting and folding.
• the parts 92 of the support 91 can be made by cutting and stamping, as illustrated in FIG. 18.
• the support 92 carries an alternation of main magnets and auxiliary magnets 95.
• the main magnets 95 may be devoid of notches 99, as illustrated in FIGS. 19 to 21. In this case, the maintenance of each main magnet 95 against the yoke 94 is obtained not thanks to circumferential lugs 97 but to the shape of the lateral faces 105 of the magnet 95.
• the faces 105 each have a flat portion 106 on which a tab 97 oriented substantially radially.
• the portions 106 and the tabs 97 are arranged so that these tabs 97 exert on the sides of the magnet 95 two stresses T1 giving a resultant stress T2 radial tend to apply the magnet 97 against the cylinder head.
• the support 92 includes tabs 97 for holding the auxiliary magnets 95.
• At least one of the permanent magnet attachment portions may be formed, if desired, by one or more beads projecting from an inner or outer face of the magnet, the support holding tab being arranged to cooperate with this or these beads to ensure its radial and angular maintenance.
• the support 51 mentioned above may be arranged to receive an alternation of main magnets and auxiliary magnets, respectively of radial and orthoradial magnetization directions.
• the magnets holding tabs on the support may have a shape other than rectangular, for example trapezoidal.
• the permanent magnets 95 have notches 110 each extending on an axial portion 111 of the magnet.
• each notch 110 has a substantially rectangular shape, with an inclined slope selected so as to that a holding tab engaged in this notch allows a maintenance both radial and angular.
• each notch 110 has a trapezoidal shape with the large base 112 located on an inner circumference, so as to provide both radial and angular support.
• FIG. 24 shows a magnetized structure 5 according to another exemplary embodiment of the invention, having a magnetization vector within the magnetized structure 5 which varies substantially sinusoidally over the entire circumference of this structure 5.
• the magnetization may have a sinusoidal profile only on certain sectors of the structure 5, and not on its entire circumference.
• the magnetized structure 5 comprises six magnetic poles N and S.
• Figure 26 illustrates the variation, as a function of the angle, of the fields Bn.no- load (vacuum induction), Bn.arm.reac (induction related to the armature reaction) and Bn. resuit (resulting induction of Bn.no-load and Bn.arm.reac), for the magnetized structure 5 illustrated in FIG. 24.
• the induction Bn. resuit is substantially sinusoidal, and the angular offset of the neutral line (where the induction vanishes) is about 5 °, as best seen in Figure 27.
• FIG. 25 illustrates these same fields for a magnetized structure with an exclusively radial magnetization.
• Bn induction. resuit substantially has a trapezoidal profile, and the angular offset of the neutral line is about 30 °, that is to say, much larger than in the invention.
• a more localized induction level is used to generate an electromotive force accelerating the inversion of the current, along a linear law associated with the local profile of a sinus, which allows to facilitate a robust definition of the electric machine, without the disadvantage of a significant loss of torque since a smaller angular offset is sufficient to switch centrally around the zero induction region.
• the magnetized structure 5 according to the invention provides a 'torque reservoir' usable according to the needs of the machine, the invention allowing an increase in torque with the same quality and quantity of magnets.
• This angular offset can be chosen greater than 10 ° electrical, or 20 ° electric as in the example described (see Figure 28).
• the invention further reduces iron losses in the armature because in sinusoidal induction the harmonic disadvantages are mitigated. Magnetic noise can be reduced as well.

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• Permanent Field Magnets Of Synchronous Machinery (AREA)

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• 2007
  • 2007-11-30 US US12/515,470 patent/US9130418B2/en not_active Expired - Fee Related
  • 2007-11-30 WO PCT/FR2007/052424 patent/WO2008074954A1/fr not_active Ceased
  • 2007-11-30 EP EP07858757A patent/EP2102965A1/de not_active Ceased
• 2015
  • 2015-09-08 US US14/847,958 patent/US20160065008A1/en not_active Abandoned

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