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
  • H02K1/2706—Inner rotors
  • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
  • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
  • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
  • H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
  • H02K1/2766—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] having a flux concentration effect

Definitions

• the present invention relates to rotating electrical machines, including synchronous machines, including motors, and more particularly the rotors of such machines.
• the invention is concerned with permanent magnet and flux concentration rotors.
• the flux concentration rotors comprise a rotor mass in which permanent magnets are housed, the latter being engaged in housings oriented most often radially.
• Permanent magnets are in a known manner magnetized so that their faces which extend both radially and longitudinally have opposite polarities, so as to allow two consecutive magnets placed in the rotor mass to have the same polarities on their faces opposite.
• the international application WO 2008/139307 relates to a rotating electrical machine comprising permanent magnets each consisting of three parallelepipeds inserted successively into the rotor, so that they are not configured to provide a keying during their implementation.
• the present invention aims to meet this need and to overcome all or part of the disadvantages mentioned above.
• the object of the invention is, according to one of its aspects, a rotating electric machine rotor with flux concentration, comprising:
• a rotor mass disposed on the shaft, having a central opening for mounting it on the shaft, and defining housings, and permanent magnets arranged in the housings, the rotor mass and the magnets being configured so as to provide a foolproof the placement of magnets in the rotor mass.
• Keying can be achieved by the special shape of the permanent magnets and allow to ensure when mounting the rotor that the magnets are inserted in the right direction in the rotor mass.
• At least one permanent magnet may be asymmetrical with respect to a median plane and better still all the permanent magnets are asymmetrical with respect to a median plane.
• At least one permanent magnet is asymmetrical with respect to a median plane (S) intersecting it in the middle, the median plane (S) extending both longitudinally and radially. All permanent magnets may be asymmetrical with respect to a median plane intersecting each corresponding magnet in its middle.
• An asymmetric permanent magnet with respect to a median plane can be asymmetrical with respect to a rotor radius cutting it in the middle.
• a housing for receiving a permanent magnet may be asymmetrical with respect to a median plane. Such a plane can extend both longitudinally and radially.
• Two consecutive magnets can thus be placed symmetrically with each other with respect to a median plane of the rotor passing between them, this plane extending both radially and longitudinally, that is to say according to the axis of rotation of the rotor, for example with respect to a radius of the rotor passing between them.
• two consecutive magnets are placed inverted in the stack.
• two consecutive housings may also be symmetrical to one another with respect to a plane containing a radius of the rotor and passing between them.
• At least one permanent magnet may have in cross section two radial edges which converge towards each other in the direction of the axis of rotation of the rotor on at least a portion of the cross section of the magnet, these radial edges respectively forming with a radius of the rotor cutting the corresponding magnet in the middle a first angle ⁇ and a second angle ⁇ , the first and second angles being different.
• All the magnets may comprise in cross section two radial edges which converge towards each other in the direction of the axis of rotation of the rotor over at least a portion of the cross section of the magnet, these radial edges forming respectively with a rotor radius intersecting the corresponding magnet in the middle a first angle a and a second angle ⁇ , the first and second angles being different.
• the permanent magnets may each have, in cross section, a shape not entirely rectangular and not completely trapezoidal.
• the magnets may for example have a shape that is both partially rectangular and partially trapezoidal.
• a magnet may comprise in cross section two edges which are parallel to one another on a first portion of the cross section of the magnet, and two edges converging towards each other towards the axis of rotation on a second portion of the cross section of the magnet.
• This second portion may be closer to the axis of rotation than the first portion.
• the permanent magnets thus have a tapered shape at their end closest to the axis of rotation, which makes it easier to keep close to the shaft a width of the rotor mass between the magnets sufficient, especially for the strength of the rotor, while benefiting from magnets having a large radial dimension and therefore a rotor mass having a large radial extent, with a shaft having a relatively small diameter.
• At least one housing, or all housing may have a shape complementary to that of the corresponding permanent magnet. At least one housing, or all housing, may receive only one magnet, at least when moving circumferentially and radially. At least one housing, or all housing, may possibly receive several magnets stacked longitudinally.
• At least one housing may have a first portion which is delimited laterally by opposite edges parallel to each other. At least one housing may have a second portion which is delimited laterally by opposite edges converging towards each other in the direction of the axis of rotation.
• a convergent edge of a housing and a consecutive convergent edge of the consecutive housing can form with a radius of the rotor passing in their middle two equal angles.
• the portion of magnetic mass defined by the two consecutive housings then comprises edges forming with respective radii of the rotor cutting the sheet portion in the middle two equal angles.
• the two consecutive edges may in one embodiment be parallel. Given the asymmetrical shape of the permanent magnets and the housings, the two edges of one portion of rotor mass out of two can be parallel to each other as one moves around the axis of rotation of the rotor, while the edges of the other magnetic mass portions converge toward the axis of rotation.
• At least one housing may have a third portion delimited by convergent opposing edges that can cooperate with the shaft to allow the drive of the rotor mass.
• the opposite edges of the third portion may or may not be rectilinear. They may for example be curved, of shape corresponding at least partially to the form of splines of the tree.
• the rotor mass may comprise a stack of layers of magnetic sheet.
• the rotor may be devoid of reported pole pieces, and the construction of the rotor can be simplified.
• the stack of magnetic sheet layers may comprise a stack of magnetic sheets, each in one piece, each sheet forming a layer of the stack.
• the stack of magnetic sheet layers may comprise one or more magnetic sheet (s) wound on it (s) itself, each sheet being able to form several layers of the stack, according to the number of holes on which it is rolled up on itself.
• a sheet may comprise a succession of sectors connected by material bridges.
• Material bridges can form the bottom of a permanent magnet housing.
• a sheet may comprise a number of sectors equal to the number of poles of the rotor.
• a sheet may comprise a number of sectors greater than the number of rotor poles, for example a multiple of the number of rotor poles, two sectors of one and the same plate that can be superimposed on one another when the sheet is wound to form the rotor mass.
• the sheet (s) may be open towards the rotor shaft.
• Each of the sheets can define at least two housings for permanent magnets, in particular at least three, better a housing number equal to the number of rotor poles, or more.
• each rotor plate is cut from a sheet of magnetic steel, for example steel 0.1 to 1.5 mm thick.
• the sheets can be coated with an electrical insulating varnish on their opposite faces before assembly within the stack. The insulation can still be obtained by a heat treatment of the sheets.
• a magnet comprises a groove, in particular a longitudinal groove, that is to say a groove extending parallel to the axis of rotation of the rotor, when the permanent magnet is in place in the rotor mass.
• the groove may be located on one of the faces of the permanent magnet which extend both radially and longitudinally. This groove thus allows keying during assembly.
• the groove can be replaced by a rib.
• the keying can also be obtained through the use of a polarizer reported on the magnet or on the rotor mass.
• the rotor mass may for example comprise a reported polarizer fixed to the sheet stack before the establishment of magnets.
• the reported polarizer can be placed on a longitudinal side of the magnet, or on a radial face of the latter.
• the polarizer reported is for example formed by a bead of glue.
• the polarizer may for example be integrated in a magnetic envelope of the permanent magnets, present on the latter before their introduction in the stack.
• the keying can also be obtained with sheets that can be slightly offset relative to each other in the stack, a magnet having a corresponding asymmetry, so as not to allow the Inserting a magnet into the stack only in one direction.
• a permanent magnet, or all permanent magnets may be in cross section of symmetrical shape with respect to a plane of symmetry, for example of rectangular or trapezoidal shape, or other, and be asymmetrical in longitudinal section, relative to at a median plane (Q) extending transversely to the axis of the rotor.
• At least one of the housings is of oblong shape, preferably elongated in a radial direction.
• all the housings are oblong, elongate in a radial direction.
• the housings may have an axis of greater size which coincides with a radius of the rotor, or not. The larger axis may be parallel to a radius.
• Such dwellings include those for which the greatest radial dimension of the housing is greater than the largest circumferential dimension of the housing, measured between two points at the same distance from the center, along a segment passing through these points and perpendicular to a bisecting beam.
• the distribution of the housings is advantageously regular and symmetrical, facilitating the cutting of the rotor sheet and the mechanical stability after cutting when the rotor mass consists of a superposition of rotor plates.
• the number of housings and magnets depends on the polarity of the rotor.
• the rotor mass may comprise any number of housing pairs, for example 6 or 8 slots.
• the dwellings may have a longitudinal dimension, in particular radial, greater than or equal to that of the permanent magnets received inside these dwellings. This may allow wider manufacturing tolerances of the rotor mass and magnets and may allow, if necessary, jamming of the magnets in the housings by centrifugation.
• Magnets can be buried in the rotor mass. In other words, the magnets are covered by the layers of magnetic sheets at the gap. The surface of the rotor at the air gap can be entirely defined by the edge of the magnetic sheet layers and not by the magnets. The housing does not open then radially outward.
• the shaft may be made of a non-magnetic material, for example non-magnetic stainless steel, which advantageously makes it possible to reduce magnetic leakage at the foot of the magnets and to improve the electromagnetic performance of the rotor.
• the shaft may comprise a nonmagnetic sleeve in contact with the rotor mass, the sleeve being mounted on a magnetic axis or not, preferably non-magnetic.
• the shaft may comprise torque transmission means for driving in rotation of the rotor mass, for example grooves at its periphery.
• the embodiment of the grooves may advantageously require only a little precision, while providing a satisfactory result in the mounting and driving of the rotor mass.
• the profile of a groove may be in cross-sectionally developing section, which may facilitate the centering of the shaft relative to the rotor mass, and excellent torque transmission.
• the profile of the grooves can be different, and the centering to be different.
• the flutes can for example be made by rolling by means of wheels, or by cutting, or broaching, or by another method.
• the grooves may extend over a portion only of the length of the shaft, and in particular over all or part of the length of the rotor.
• the flutes may extend over several portions of the length of the shaft, separated by one or more portions without flutes, for example two fluted portions each located at one end of the rotor mass.
• the length of the grooved zone (s) may be chosen so as to be sufficient to allow the transmission of torque, while at the same time making it possible to limit the manufacturing difficulties of these splines.
• the number of splines may be equal to the number of poles of the rotor, or be a multiple of the number of poles of the rotor, for example double.
• the grooves extend radially beyond permanent magnets.
• the permanent magnets are farther from the axis of rotation than the top of the flutes.
• the grooves thus cooperate with a sheet portion that is not radially at the same level as one or more magnets.
• the grooves protrude in the stack between two consecutive permanent magnets.
• the flutes extend radially at least partially between the permanent magnets.
• At least one permanent magnet may comprise a mark making it possible to differentiate one from the other its two longitudinal end faces. It may be for example a colored sign. This mark can help the operator to correctly orient the magnet when inserted into the corresponding slot.
• All permanent magnets may include a mark for differentiating the two longitudinal end faces of a magnet from one another. These marks can allow easy and quick visual inspection of the correct placement of the magnets in their housing after assembly. For example, when we observe the rotor along its axis of rotation by one of its ends, we can see the presence of the mark on all magnets on one side, and no mark on the other side. As a variant, especially in the case where two consecutive housings are different and symmetrical with respect to each other, it is possible to note the presence of a mark on one magnet out of two, and the same is true when observe the rotor on the other side.
• the rotor can be cantilevered or not.
• the rotor mass may comprise one or more holes to lighten the rotor, to allow its balancing or for the assembly of the rotor plates constituting it. Holes may allow the passage of tie rods now integral with the sheets.
• the sheet layers can be snapped onto each other.
• the housings can be filled at least partially with a non-magnetic synthetic material. This material can lock in place the magnets in the housing and / or increase the cohesion of the sheet package.
• the rotor mass may comprise, where appropriate, one or more reliefs contributing to the proper positioning of the magnets, especially in the radial direction.
• the rotor mass may have an outer contour which is circular or multilobed, a multi-lobed shape may be useful for example to reduce torque ripples or harmonics of current or voltage.
• the rotor can receive an outer ring, which surrounds the package of sheets. This can reduce the length of the material bridge connecting two consecutive sectors.
• the invention also relates to a rotating electrical machine, such as a synchronous motor or a synchronous generator, comprising one of the rotors as defined above.
• This machine may comprise a stator with concentrated or distributed winding.
• FIG. 1 is a diagrammatic and partial perspective view of an exemplary rotor made in accordance with the invention
• FIG. 2 is a schematic and partial perspective view of the rotor shaft of FIG. 1,
• FIG. 3 is a cross-section, diagrammatically and partially, of the rotor of FIG. 1;
• FIG. 4 represents, in isolation and from the front, a magnetic sheet
• FIG. 5 represents a detail of FIG. 4,
• FIG. 6 represents a detail of embodiment of FIG. 3,
• FIG. 7 is a view similar to FIG. 6 illustrating an alternative embodiment
• FIGS. 8 to 11 are cross sections of embodiments of permanent magnets according to the invention, and FIG. 12 is a longitudinal section of the permanent magnet of FIG.
• the rotor 1 shown in FIG. 1 comprises a rotor magnetic mass 3 extending axially along the axis of rotation X of the rotor, this rotor mass being for example formed by a stack of magnetic sheets 4 stacked along the X axis, the sheets being for example identical and superimposed exactly. They can be held in each other by clipping, rivets, welds or any other technique.
• the rotor mass may comprise at least one magnetic sheet wound on itself.
• a sheet comprises a succession of sectors 4a connected by material bridges 4b, the material bridges can form the bottom of a housing of a permanent magnet.
• the magnetic sheets are preferably magnetic steel. All grades of magnetic steel can be used.
• the rotor mass 3 is mounted on a shaft 2 which, in the example considered, is made of a non-magnetic material, for example non-magnetic stainless steel or aluminum.
• the material may for example be type 304 nonmagnetic stainless steel.
• the rotor mass 3 comprises a central opening 5 for mounting on the shaft 2.
• the fixing of the rotor mass 3 on the shaft 2 can be done by means of an axial locking system, for example with one side a stop 2b material and on the other side a serrated stop washer 6.
• the assembly can be performed cold or hot.
• the transmission of the torque is obtained by grooves 2a disposed at the periphery of the shaft 2.
• the profile of a groove may be in cross-section in involute of a circle, which may allow a satisfactory centering of the shaft relative to the rotor mass, and excellent torque transmission.
• the flutes may extend over one or more portions only of the length of the shaft, as illustrated in Figure 2, where the flutes extend over two portions of the length of the shaft separated by a portion without flutes, each located at one end of the rotor mass.
• the clearances 2c obtained on either side of the fluted portions may allow to receive any chips that would be formed during the establishment of the rotor mass 3 on the shaft 2, and not to disturb the correct axial positioning from the whole.
• the stiffness of the rotor mass is preferably chosen so that the latter can be deformed during assembly on the spline shaft.
• the rotor 1 comprises a plurality of permanent magnets 7 arranged in corresponding housings 8 of the rotor magnetic mass 3, so that two consecutive magnets 7 have the same polarities on their facing faces.
• the magnets may for example be made of ferrite or alternatively rare earths, for example neodymium or other type.
• the rotor mass is configured to allow the placing of the magnets in the stack of magnetic sheet layers in one direction, so as to play the role of polarizer during assembly.
• the permanent magnets are asymmetrical for this purpose.
• the rotor 1 is disposed inside a not shown stator, which comprises for example a concentrated or distributed winding.
• This stator makes it possible to generate a rotating magnetic field driving the rotor in rotation, in the context of a synchronous motor, and in the case of an alternator, the rotation of the rotor induces an electromotive force in the stator windings.
• the housings 8 do not open on the outside of the rotor sheet.
• the housings 8 may in particular be separated from the periphery of the rotor sheet by the material bridge 4b formed in the sheet, of a thickness e preferably between 0.1 and 3 mm.
• the sectors 4a and the housings 8 have a shape corresponding to that of the magnets, and the shape of the sectors 4a toward their free end closest to the shaft corresponds to the shape of the grooves 2a, as illustrated in FIG. 5.
• Each housing 8 may have a radial dimension / greater than that of the corresponding magnets. More particularly, each housing 8 may comprise a main portion 8a whose radial dimension corresponds to that of the associated magnet 7, and an end portion 8b radially internal to the magnet 7, as shown in FIG. 6.
• the main portion 8a of a housing has for example a shape that corresponds substantially to that of the magnet 7, in cross section.
• a magnet 7 has in cross section two radial edges 34 which are parallel to one another on a first portion 7a of the cross section of the magnet, and two radial edges 35 converging on one side. towards the other towards the axis of rotation on a second portion 7b of the cross section of the magnet, and the housing 8 has on the main portion 8a opposite edges 30 of corresponding shape, parallel to each other along the first portion 7a and opposite edges 31 converging along the second portion 7b of the magnet.
• the magnets are thus asymmetrical in cross section each relative to a respective median plane S.
• Two consecutive magnets are placed symmetrically one of the other relative to a plane P passing between them, as illustrated in FIG. 4.
• the planes P and S are planes extending both radially and longitudinally. Thus, two consecutive magnets are placed inverted in the housing of the sheets.
• two consecutive housings 8 are symmetrical to each other with respect to the plane P passing between them.
• the two consecutive edges 31 of two consecutive housings on the second portion 7b of the magnets are in the exemplary embodiment illustrated parallel to each other when one moves around the axis of rotation of the rotor and defines an end sheet portion 4c 'of the sector 4a having parallel edges.
• a convergent edge 31 of a housing and a consecutive convergent edge 31 of the subsequent housing can form with a radial plane of the rotor passing in their middle two equal angles.
• the sheet portion 4c "defined by the two consecutive housings and comprises edges 31 forming with a radius of the rotor intersecting in the middle each an angle ⁇ , the two angles ⁇ being equal, the two edges being convergent towards the
• ends of sectors 4c 'with parallel edges 31 alternate with ends of sectors 4c' 'with convergent edges 31 as one moves around the axis of rotation of the rotor, as can be seen from FIG. in Figure 6.
• the housing 8 further has an end portion 8b which is delimited laterally by convergent opposite edges 32 towards each other in the direction of the axis of rotation.
• the opposite edges 32 may be rectilinear or not. They can for example be curved. In the example described, the edges 32 have the shape of a involute of circle, so that the profile of the sheet corresponds to the profile of the corresponding groove 2a.
• the edges 32 open into the central opening of the rotor. These edges convergent opposites 32 of the second portion cooperate with the shaft to allow the drive of the rotor mass.
• the grooves 2a extend radially beyond the permanent magnets.
• the permanent magnets extend radially beyond the flutes.
• the grooves 2a thus cooperate with a sheet portion which is not radially adjacent to one or more magnets.
• the grooves 2a can project into the stack between two consecutive permanent magnets.
• the flutes extend radially at least partially between the permanent magnets. If necessary, the grooves can come directly into contact with the magnets.
• All permanent magnets may have an M mark to differentiate the two longitudinal end faces of a magnet from one another. For example, as illustrated in FIG. 3, when the rotor is observed along its axis of rotation by one of its ends, the presence of the mark on one magnet out of two is observed, and it is the same when the rotor is observed on the other side. This result is due to the fact that in the example described two consecutive housings are different and symmetrical with respect to each other.
• a synthetic material can be injected into the housings 8, so as to block the magnets in the housing 8 and / or ensure the cohesion of the sheet package.
• the material used is for example an epoxy resin or a thermoplastic material.
• the locking of the magnets 7 can also be effected by clamping under the action of the centrifugal force.
• a magnet may comprise a groove.
• FIG. 8 illustrates an embodiment of a permanent magnet 7 comprising a longitudinal groove 60, that is to say a groove extending along the axis of rotation of the rotor, when the permanent magnet is in position. place in the rotor mass.
• the groove may be located on one of the faces that extend both radially and longitudinally of the permanent magnet. This groove thus allows keying during assembly.
• the rotor mass has a corresponding shape, the sheets comprising, for example, tongues intended to cooperate with the grooves of the magnets.
• the keying can also be obtained through the use of a polarizer reported on the magnet or on the rotor mass.
• a polarizer reported on the magnet or on the rotor mass.
• the polarizer 61 can be placed on a longitudinal face of the magnet, as shown in FIG. 9, or alternatively on a radial face thereof, as illustrated in Figure 10. It can be fixed by gluing for example or by other means on the magnet, or on the rotor mass. It can be formed by a bead of glue, if necessary.
• the keying can also be obtained with sheets that can be slightly offset relative to each other in the stack, a magnet having a corresponding asymmetry, so as not to allow the Inserting a magnet into the stack only in one direction.
• the permanent magnet is in cross section of symmetrical shape with respect to a plane of symmetry S, as illustrated in FIG. 11, being for example of rectangular shape as illustrated, or trapezoidal, or other, and being asymmetric in nature. longitudinal section, with respect to a median plane Q extending transversely to the axis X of the rotor, as illustrated in FIG. 12.
• the sheets can be made with holes to allow the passage of connecting rods of the laminations of the rotor mass.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=47520191

Family Applications (1)

Country Status (3)

Family Cites Families (8)

• 2011
  • 2011-11-18 FR FR1160529A patent/FR2983008B1/fr active Active
• 2012
  • 2012-11-16 EP EP12812373.4A patent/EP2781006A2/de not_active Withdrawn
  • 2012-11-16 WO PCT/IB2012/056500 patent/WO2013072890A2/fr active Application Filing

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events