EP3785349A1

EP3785349A1 - Rotor for a rotating electrical machine

Info

Publication number: EP3785349A1
Application number: EP19718178.7A
Authority: EP
Inventors: Jacques Saint-Michel
Original assignee: Moteurs Leroy Somer SAS
Current assignee: Moteurs Leroy Somer SAS
Priority date: 2018-04-23
Filing date: 2019-04-19
Publication date: 2021-03-03
Also published as: JP2021522767A; FR3080500A1; WO2019206830A1; FR3080500B1; KR20210003758A; US20210234417A1; CN112020811A

Abstract

The invention relates to a rotor for an electrical machine, rotating about an axis of rotation (X), the rotor including: - salient poles (13) forming notches (11) therebetween, the salient poles each having a generally asymmetric shape in relation to a radial median plane containing the axis of rotation (X) of the machine; and - coils (12), each coil (12) being provided on a corresponding salient pole (13), in the notches adjacent to this salient pole.

Description

ROTOR OF ROTATING ELECTRIC MACHINE

The present invention relates to the field of rotating electrical machines, in particular synchronous machines, and more particularly the rotors of such machines. The invention is more particularly concerned with the projecting pole rotors between them notches in which are received coils.

It is known to produce a rotor with salient poles, in which the salient poles are symmetrical with respect to a radial axis of the pole. The poles may each comprise two symmetrical pole openings, arranged on either side of the pole towards its free end. The presence of such polar expansions makes it more difficult to wind on the pole and almost impossible the insertion of coils already manufactured.

There is therefore a need to benefit from a rotor of rotating electrical machine for easy placement of the coils in the notches, while ensuring good electromagnetic performance.

The invention aims to meet this need and it succeeds, according to one of its aspects, thanks to an electric machine rotor, rotating about an axis of rotation X, the rotor comprising:

- projecting poles forming between them notches, the salient poles each being of generally asymmetrical shape with respect to a median radial plane containing the axis of rotation X of the machine,

- Coils, each coil being disposed on a corresponding salient pole, in the notches adjacent to this salient pole.

By "asymmetrical" is meant that the projecting pole is symmetrical with respect to any radial plane containing the axis of rotation of the machine. Preferably, all the salient poles are of asymmetrical general shape.

The radial plane considered may be a median plane for the corresponding pole. The median plane can pass through the middle of the pole surface at the gap and / or through the center of the pole at its attachment to the rotor mass.

The convex envelope of each of the poles may have a plane of symmetry when observed in cross section, perpendicular to the axis of rotation.

"Convex envelope" means the smallest convex form in which the pole is inscribed. The convex envelope is the tight closed line which follows the outline of the pole, connecting the convex contours of the pole between them. The convex envelope is the closed line of minimal length, which is superimposed on the convex or rectilinear portions of the perimeter of the pole and follows ropes joining each time two convex or rectilinear portions separated by a concave portion (seen from the outside). A convex hull corresponds to the region that would be delimited by a stretched elastic that would rely exclusively on the perimeter of the pole.

The projecting pole may extend along a radial axis of the pole, which may be contained in the radial plane mentioned above. By "radial axis of the pole" means a Y axis of the pole oriented radially, that is to say, according to a radius of the rotor. In the invention, it is not an axis of symmetry for the pole. This radial axis can intersect the summit of the pole. It can be a median axis.

Thanks to the invention, the nucleus of the salient pole may be wider than a symmetrical pole core, so that the saturation is less rapidly reached. By "nucleus" is meant the part of the pole other than the polar ones.

The rotor according to the invention makes it possible to obtain a machine having electromagnetic performances, a compactness and an improved cost.

Each projecting pole may comprise a lateral polar development, in particular on a first lateral face of the salient pole, when the rotor is observed along the axis of rotation X. The lateral pole blooming on the salient pole makes it possible to increase the width of the pole. protruding towards its free end, so that one has more flux in the poles, and one thus obtains a higher power. The risk of saturation in the salient poles can also be minimized. The lateral polar development may be located towards the free end of the salient pole and the first lateral face. The lateral polar development can be located at the front of the pole or at the rear of the pole. The front and the back of a pole are defined with respect to the direction of rotation of the rotor. Each projecting pole has a front side face and a rear side face.

Each projecting pole may comprise at least one lateral face devoid of polar expansion.

The lateral polar expansion is preferably located on the rear face, the first lateral face being the rear face of the pole, when the rotor is intended to be included in a rotating electrical machine used as a motor. For a motor, the rotor preferably rotates in the counterclockwise direction. Thus, the circulation of the flow is shifted towards the front of the pole. In this case, the first lateral face is the rear lateral face of the salient pole.

The lateral polar expansion is preferably located on the front face, the first side face being the front face of the pole, when the rotor is intended to be included in a rotating electrical machine used as a generator. For a generator, the rotor preferably rotates clockwise. Thus, the circulation of the flow is shifted towards the rear of the pole. In this case, the first lateral face is the front lateral face of the salient pole. Such a configuration has the advantage of reducing the braking torque when operating in generator mode, which can be particularly advantageous in automotive traction.

In the case where the rotor has a plurality of projecting poles, the lateral pole shoeings of the salient poles may all be located on the same side face. For example, the lateral pole openings of the salient poles of the rotor are all located on the front lateral face of the corresponding salient pole. In a variant, the lateral pole openings of the salient poles of the rotor are all located on the rear lateral face of the corresponding salient pole.

Each projecting pole may comprise a second lateral face opposite to the first lateral face, this second lateral face being devoid of polar expansion. The winding is facilitated, and the insertion of the coils on the poles is easier, thanks to the lack of polar expansion on one side of the salient pole.

As a variant, each projecting pole may comprise a second polar expansion, of a shape other than that of the lateral polar expansion situated on the first lateral face of the salient pole. The second polar bloom may be smaller than the first polar bloom. Thus, the salient poles may be wider than if they had two polar openings of the same size, especially at their nucleus.

The second lateral face may extend in a radial plane Z or at an angle g with a radial plane passing through its base, in particular by the point of intersection of the bottom of the notch adjacent to said projecting pole with the second lateral face.

Such a configuration makes it possible to maximize the width of the projecting pole at its base, while allowing the housing of the coils. The notches are open radially outwards and towards the gap. The rotor is an inner rotor, intended to be received in an outer stator.

The second side face can make an angle b with the first side face. This angle b may be non-zero. The first and second side faces are not parallel to each other.

The coils may have been inserted on the corresponding salient poles after winding. The reels can be prepared separately. In the invention, the rotor is not wound directly on the tooth. The rotor according to the invention is preferably a concentrated winding rotor, that is to say that each coil of the rotor extends in two consecutive notches around a single pole projecting from the rotor.

A coil, better all the coils, may comprise first and second portions received in two adjacent notches, said first and second portions being respectively at distances d1 and d2 of the axis of rotation X. The distances d1 and d2 may be equal or different.

The first portion of a coil is one that is placed in a first notch and the second portion is the one that is placed in a second notch, adjacent to the first.

When the distances d1 and d2 are different, the coil is called "deformed", its first and second portions being connected by a coil portion which may have an inflection.

Alternatively, a coil may comprise first and second portions received in two adjacent notches, said first and second portions being located at the same distance dl of the axis of rotation X. Another coil may comprise first and second portions received in two adjacent notches, said first and second portions being situated at the same distance d2 from the axis of rotation X. Thus, two different coils, in particular two adjacent coils, may comprise first and second portions located respectively at distances d1 and d2 of the axis of rotation X, which are different. In one embodiment, the rotor comprises an alternation of coils whose first and second portions are located at the same distance dl of the axis of rotation X, and coils whose first and second portions are located at the same distance d2 of the axis of rotation X. A coil, better all the coils, can be maintained on the corresponding salient pole by an adjacent coil and / or by a polar expansion.

In a first embodiment, a coil can be held on the corresponding salient pole by the two adjacent coils.

In a second embodiment, a coil may be held on the corresponding salient pole by two polar openings of the two adjacent salient poles.

In a third embodiment, a coil may be held on the corresponding salient pole on one side by an adjacent coil and on the other by a pole shoe corresponding to the corresponding salient pole.

In a fourth embodiment, a coil may be held on the corresponding salient pole on one side by an adjacent coil and on the other by a polar expansion of the adjacent salient pole.

By "adjacent coil" means the coil disposed on the salient pole adjacent to the salient pole corresponding to the coil in question. The two adjacent coils extend partly in the same notch. Said notch is formed between the two salient poles carrying the two adjacent coils considered.

The invention also relates, independently or in combination with the foregoing, to an electric machine rotor, rotating about an axis of rotation X, the rotor comprising:

- projecting poles forming between them notches, the salient poles each being for example generally asymmetrical with respect to a radial plane containing the axis of rotation X of the machine, better all the salient poles can be of asymmetrical general shape ,

- Coils, each coil being disposed on a corresponding projecting pole, in the notches adjacent to said projecting pole, rotor in which at least one coil comprises first and second portions received in two adjacent notches, said first and second portions being located respectively at distances d1 and d2 of the axis of rotation X, the distances d1 and d2 being different.

In an exemplary embodiment, all the coils of the rotor comprise first and second portions received in two adjacent notches, said first and second second portions being respectively at distances dl and d2 of the axis of rotation X, the distances dl and d2 being different.

Rotor mass and shaft

The rotor may comprise a shaft extending along the axis of rotation, on which is disposed a rotor magnetic mass comprising the salient poles.

The shaft may be made of a magnetic material, which advantageously makes it possible to reduce the risk of saturation in the rotor mass and to improve the electromagnetic performances of the rotor.

In a variant, the rotor comprises a non-magnetic shaft on which the rotor mass is arranged. The shaft can be made at least partly from a material of the following list, which is not limiting: steel, stainless steel, titanium or any other non-magnetic material

In one embodiment, the rotor mass may be arranged directly on the non-magnetic shaft, for example without an intermediate rim. Alternatively, especially in the case where the shaft is not non-magnetic, the rotor may comprise a rim surrounding the rotor shaft and coming to bear on the latter.

The rotor mass extends along the axis of rotation and is arranged around the shaft. The shaft may comprise means for transmitting torque to the rotor mass.

The rotor mass may be formed of a stack of magnetic sheets. Each magnetic sheet can be in one piece. A sheet may comprise a succession of sectors connected by tangential material bridges.

The poles can be in one piece with the rest of the rotor mass, or reported thereon.

For example, each rotor plate is cut from a sheet of magnetic steel, for example 0.1 to 1.5 mm thick steel. 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.

Alternatively, the rotor mass may comprise a plurality of pole pieces assembled on the rotor shaft, which is in this case preferably non-magnetic. The assembly can be made by dovetails on a shaft of the machine, or alternatively by means of tie rods. Each pole piece may comprise a stack of magnetic sheets. 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 sheets can be cut in a tool after each other. They can be stacked and clipped or pasted into the tool, in complete packages or subpackages. The sheets can be snapped onto each other. Alternatively, the sheet package can be stacked and welded outside the tool.

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 be mounted cantilevered or not, relative to the bearings used to guide the shaft.

The rotor may be made of several sections aligned in the axial direction, for example at least two sections. Each of the sections may be angularly shifted relative to the adjacent pieces ("step skew" in English).

The notches can be straight or helical.

Rotor coils

The rotor coils are arranged in the notches in a concentrated manner. By "concentrate", understands that each coil is wrapped around a single pole protruding from the rotor.

The coils comprise electrical conductors. The electrical conductors may be in cross section of circular shape, or flattened, or substantially polygonal, in particular rectangular.

When the conductors are of circular cross section, they can be arranged in the notch according to a hexagonal stack. When the conductors are of flattened cross section, they may be arranged in the notch in one or more rows, especially in a single row, being adjacent to each other by their long sides, otherwise called the flat. The optimization of the stack can allow to have in the notches a larger amount of electrical conductors, and parallel to reduce the useful surface of the notch, so to obtain a rotor of greater power at constant volume. A coil may contain one or more rows of electrical conductors, for example one, two, three or four rows. The electrical conductors in the notches may be substantially rectangular in cross section. Preferably, the electrical conductors may be of flattened cross section, with a large axis parallel to the face of the tooth. The electrical conductors can thus be wound on flat.

The electrical conductors of a coil can be wound on edge or flat. By "singing" is meant the narrow face of the electrical conductor of the coil, as opposed to "flat". A coil wound on edge is a coil whose electrical conductor, of rectangular cross section, having a direction of elongation, is wound perpendicular to this direction of elongation. The electrical conductor is thus wound around a winding axis preferably parallel to the direction of elongation of its cross section.

The coils can be arranged in a cluster of several coils. In other words, the same electrical conductor forms several coils interconnected. [

The coils can be wound alone or in a cluster, then deformed.

The electrical conductors may be randomly arranged in the notches or in a row. Preferably, the electrical conductors are stored in the notches. By "rows" is meant that the conductors are not arranged in the notches in bulk but in an orderly manner. They are stacked in the slots in a non-random manner, being for example arranged in rows of aligned electrical conductors. The stack of electrical conductors is for example a stack in a hexagonal network in the case of electrical conductors of circular cross section or a stack in one or more rows in the case of electrical conductors of rectangular cross section.

The electrical conductors are preferably made of metal, in particular copper or aluminum.

The electrical conductors are insulated by a surface coating. They can be glazed. The enamel can be thermosetting. Electrical conductors can be enamelled and gimped. The wrapping consists of surrounding the electrical conductor with an insulating tape of glass fibers, in order to give it mechanical protection, which may especially be advantageous for large machines.

The coils may have a shape to promote heat exchange with a cooling fluid. For example, a coil may have a asymmetrical bun. A coil bun is said to be asymmetrical if it is asymmetrical by at least one of its length, angle with respect to the axis of rotation, form, this list not being limiting.

In order to promote the cooling of the coil, it may comprise one or more axial openings.

The input and output of each coil can be located on either side of the coil or on the same side. The connections are preferably located in the lower part of the coils, closer to the shaft, which improves the mechanical strength in rotation. In this case, an even number of layers of conductors in the coil is required.

Input and output variant at the top and bottom respectively

Preferably, the coils are separated from the walls of the notch by an insulator, in particular by at least one insulating sheet.

The coils are covered with insulation before they are installed on the rotor mass.

The insulation may be of Nomex ™ type, based on aramid fibers, or triplex, comprising a stack of layers such as for example a layer of Nomex ™, a layer of Mylar ™, then a layer of Nomex ™. The insulation can be glued or not.

The coils covered with insulation can then be impregnated with a resin or a varnish, in particular before their insertion on the salient poles.

The coils can be impregnated each individually, or the complete rotor can be impregnated.

The impregnation can be done by soaking or VPI ("Vacuum Pressure Impregnation" in English).

In a variant embodiment, the bunches can undergo mechanical tying, for example with a Dacron ™ (polyamide) ribbon.

The coils can be wedged in the notches, to lock them in position in the pole. It is possible for this purpose to use wedges, for example wedges screwed or clipped in the notches. The wedges can be made of aluminum or plastic and have different shapes. The shims can act as a dissipator to improve heat exchange with the cooling fluid. The shims can be arranged to let through the cooling fluid circulation channels. The cooling fluid can be air, water, oil. Machine and stator

The invention also relates to a rotating electrical machine, comprising a rotor as defined above. The machine can be used as a motor or as a generator. The machine can be reluctant. It can constitute a synchronous motor or alternatively a synchronous generator. In another variant, it constitutes an asynchronous machine.

The machine has a stator. The latter has teeth defining between them notches. These notches can be closed to the gap.

In one embodiment, the stator may include a one-piece breech bearing the teeth. The notches can be closed, both towards the cylinder head and towards the gap.

In an alternative embodiment, the stator comprises a toothed crown comprising teeth defining between them notches open radially outwardly, and a yoke attached to the toothed crown.

The stator may comprise windings arranged in a distributed manner in the notches, including electrical conductors arranged in a row in the notches.

By "distributed" is meant that at least one of the windings passes successively in two non-adjacent notches.

By "bolt reported", it should be understood that the cylinder head is not made in one piece with the ring gear but attached to the latter during the manufacture of the stator.

Electrical conductors may not be arranged in the notches in bulk but in an orderly manner. They are stacked in the slots in a non-random manner, being for example arranged in rows of aligned electrical conductors. The stack of electrical conductors is for example a stack in a hexagonal network in the case of electrical conductors of circular cross section.

The installation of the windings can be facilitated on the one hand in that the access to the interior of the notches is easier, being notches open wider and towards the outside rather than the air gap , and secondly in that the space available around the serrated crown, for the necessary tools or even for a winding machine, is much larger than the space available in the bore of the stator. Moreover, the winding operation is relatively inexpensive, insofar as it can be carried out in a similar manner to the winding of a rotor of a DC or asynchronous machine with wound rotor.

The serrated crown is formed of all the stator teeth joined at their base on the side of the gap. The teeth are joined by tangential bridges.

At least one notch may be closed on the gap side by a tangential bridge connecting two consecutive teeth of the toothed crown, better all the notches may be closed on the gap side each by a tangential bridge connecting the two consecutive teeth of the serrated crown. The tangential bridge or bridges are of constant width. In a variant, the tangential bridge or bridges are of decreasing and then increasing width.

At least one notch may have radial edges parallel to each other, better all the notches.

At least one notch may be in cross section, perpendicular to the axis of rotation, of a shape chosen from the following list: rectangular, hexagonal, this list not being limiting. Preferably, at least one notch is in cross section with a narrowing bottom towards the air gap, in particular of hexagonal shape. Preferably, the shape of the notch corresponds to the shape of the stack of electrical conductors disposed in the latter, which may be the case in particular when the notch is of hexagonal cross section. In addition, the tangential bridges are in this case of non-constant width, decreasing and then increasing linearly. Such a configuration of the tangential bridges makes it possible to minimize the harmonics, to obtain more torque by desaturation of the teeth and the cylinder head, and to improve the heat transfers.

At least one tooth, better all the teeth, may be generally trapezoidal in cross section.

The electrical conductors in the notches may be in cross section of circular shape, or polygonal, including rectangular, this list is not limiting. When the conductors are of circular cross section, they can be arranged in the notch according to a hexagonal stack. When the conductors are of rectangular cross section, they can be arranged in the notch in a single row, being adjacent to each other by their long sides. The optimization of the stacking can make it possible to place in the notches one more large amount of electrical conductors, and parallel to reduce the useful area of G notch, so to obtain a stator of greater power at constant volume.

The serrated crown can be made by helically winding a straight strip of teeth connected by tangential bridges, the teeth of the rectilinear strip leaving between them notches which have convergent edges, the edges of the notches becoming substantially parallel to each other when the band is wound on itself to form the serrated crown. The band may alternatively be formed of sectors each having several teeth, the sectors being connected by bridges of material, these sectors being cut in a straight sheet metal strip.

The cylinder head can also be made in a similar manner, either by directly winding a sheet metal strip if its width allows it, or by forming in said sheet metal strip adapted slots during cutting, so as to facilitate this winding.

The cylinder head can be attached to the serrated crown after the windings have been installed in the notches.

In an alternative embodiment, the stator is concentrated winding. The stator may include teeth and coils disposed on the teeth. The stator can thus be wound on teeth, in other words with non-distributed winding.

The stator teeth may have polar expansions. Alternatively, the stator teeth are devoid of polar expansions.

The stator may include an outer carcass surrounding the breech.

The stator teeth can be made with a stack of magnetic sheets, each covered with an insulating varnish, in order to limit the losses by induced currents.

The machine can operate at a nominal peripheral speed (tangential velocity taken at the outer diameter of the rotor) which may be greater than or equal to 100 meters per second. Thus, the machine according to the invention allows operation at high speeds if desired.

The rotary electric machine according to the invention may have an outside diameter, for example between 100 and 500 mm, better still between 120 and 400 mm, being for example of the order of 200 mm. The inside diameter is for example less than or equal to 300 mm, being in particular between 60 mm and 180 mm. The power of the machine can be between 1 and 300 kW, being for example of the order of 100 kW, this value being in no way limiting.

The machine may comprise a single inner rotor or, alternatively, a single outer rotor, or alternatively an inner rotor and an outer rotor, arranged radially on either side of the stator and coupled in rotation.

The number of notches per pole and per phase can be integer or fractional.

The number of poles P on the rotor is for example between 4 and 48, being for example 4, 6, 8, 10 or 12, and the number of teeth S to the stator is for example between 6 and 48.

Manufacturing process

The invention further relates, independently or in combination with the foregoing, to a method of manufacturing a rotor as defined above, comprising the following steps:

a) preparing a coil on a core, said coil having first and second portions to be received in notches of the rotor,

b) inserting a first portion of the coil into a first notch adjacent to the first side face of a projecting pole, said first side face having a lateral pole expansion,

c) inserting a second portion of the coil into a second slot adjacent to the second side face of said projecting pole.

A coil may thus comprise first and second portions received in two adjacent notches. The first and second portions are inserted so as to be respectively at distances d1 and d2 of the axis of rotation X, the distances d1 and d2 being equal or different.

Each coil may be formed of at least one wire of rectangular cross section wound on itself, especially on edge or flat. The yarn is preferably wound in a contiguous manner.

In one embodiment, a coil is held on the corresponding salient pole by an adjacent coil and / or by a pole shoe. The first portion of the coil can be held under the polar expansion of the corresponding salient pole carrying the coil or under a second coil inserted later. Alternatively, one can maintain the second portion of the coil under the polar expansion a projecting pole adjacent to the projecting pole carrying the coil or under a second reel inserted later.

It can deform the coil during its insertion. It is possible to deform the coil so as to obtain a coil comprising first and second portions, intended to be received in two adjacent notches, which are situated respectively at distances d1 and d2 of the axis of rotation X, the distances d1 and d2 being different. The first and second portions are then connected by a coil portion which may have an inflection.

It is possible to shift the coil during its insertion, in particular circumferentially, so as to keep it under a polar expansion. In one embodiment, the coil is shifted to maintain its first portion under the polar expansion of the corresponding salient pole carrying the coil. In another embodiment, the coil is shifted to maintain its second portion under the polar expansion of a salient pole adjacent to the salient pole carrying the coil.

In one embodiment, the coils are inserted on the salient poles of the rotor individually.

Alternatively, they are inserted all at once. The invention thus object, independently or in combination with the foregoing, a method of manufacturing a rotor, particularly as defined above, comprising the following steps:

i) inserting the first portions of all the reels at a time in the corresponding notches, then

ii) inserting the second portions of all the reels at a time in the corresponding notches,

iii) the reels are shifted circumferentially, in particular so as to maintain a coil on the corresponding projecting pole by an adjacent coil and / or by a polar expansion.

detailed description

The invention will be better understood on reading the detailed description which follows, examples of non-limiting implementation thereof, and on examining the appended drawing, in which:

FIG. 1 is a diagrammatic and partial view, in cross section, of a rotary electric machine according to the invention, FIGS. 2a and 2b are cross-sectional views of the machine of FIG. 1, respectively showing the induction and the flow lines in the machine,

FIGS. 3a to 3c are views similar to FIG. 1 of alternative positioning of the coils on the salient poles,

FIG. 4 is a view similar to FIG. 1 of a variant embodiment of a stator,

FIG. 5 is a schematic and partial perspective view of a machine variant, and

- Figure 6 is a view similar to Figure 1 of an alternative embodiment.

FIG. 1 illustrates a rotating electrical machine 10 comprising an inner rotor 1 and an outer stator 2. The stator makes it possible to generate a rotating magnetic field driving the rotor 1 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 stator 2 comprises windings 22, as illustrated, which are arranged in notches 21 formed between teeth 23 of a toothed crown 25. In addition, the stator comprises a yoke 29 attached to the toothed crown 25. The stator further comprises an outer carcass surrounding the breech, not shown.

The coils 22 are distributed in the notches 21 and have electrical conductors arranged in a row in the notches 21.

The notches 21 are in the example described with radial edges parallel to each other, and are in cross section of generally rectangular shape.

The notches 21 are closed towards the gap by tangential bridges 27 interconnecting two consecutive teeth of the toothed crown 25. The tangential bridges 27 are of non-constant width, decreasing and increasing.

The toothed crown 25 is made by helically winding a band of teeth connected by tangential bridges 27. The teeth 23 of the band form between them the notches 21 which have convergent edges, the edges of the notches being parallel to each other when the band is wound on itself to form the serrated crown.

Each notch 21 comprises two stacked windings, thus two winding stages. The thickness e of the cylinder head can be relatively large, compared to known machines. It is the same with the width / teeth.-One can thus obtain a significant reduction in the electric field consumption (or ampere-turns) to the stator, or a significant increase in the flow through the stator.

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 stacked along the X axis, the plates being for example identical and superimposed exactly. They can be held together by clipping, rivets, tie rods, welds or any other technique. The magnetic sheets are preferably magnetic steel. All grades of magnetic steel can be used.

The rotor mass 3 comprises a central opening for mounting on a shaft 5. The shaft may, in the example considered, be made of a non-magnetic material, for example non-magnetic stainless steel or aluminum, or on the contrary be magnetic.

According to the invention, the rotor 1 comprises projecting poles 13 forming notches 11 between them. The rotor 1 further comprises coils 12, each coil being disposed on a corresponding projecting pole 13, in the notches 11 adjacent to said salient pole. .

The salient poles 13 are generally asymmetrical in relation to a median radial plane containing the axis of rotation X of the machine. The salient poles 13 each comprise a lateral pole shoe 14, located on a first lateral face 14a of the projecting pole, when the rotor is observed along the axis of rotation X, towards the free end of the salient pole. In the example described, the lateral pole shoe is located on the rear lateral face of the salient pole. The salient poles have a second side face 14b opposite the first side face 14a, which is devoid of polar expansion, and may have at its end a chamfer 14c facilitating the insertion of the coils.

In this example, the circulation of the flow is offset towards the front of the direction of rotation of the rotor, as illustrated in FIGS. 2a and 2b. Saturation in the salient pole is less quickly attained.

The second lateral face 14b extends in a plane forming an angle g with a radial plane Z. The second side face 14b makes an angle b with the first side face 14a. This angle b is non-zero. The first and second lateral faces are not parallel to each other.

The positioning of the coils in the notches 11 will now be described with reference to FIGS. 3a to 3c.

Each coil 12 has first 12a and second 12b portions respectively received in two adjacent slots 11.

These first and second portions 12a and 12b may be located respectively at distances d1 and d2 of the axis of rotation X which are different, as illustrated in FIGS. 3a and 3b. When the distances d1 and d2 are different, the coil is deformed, its first and second portions being connected by a curved coil portion. In the example of Figure 3a, the coil is held on the corresponding projecting pole on one side by an adjacent coil and the other by a pole shoe 14 of the adjacent salient pole. In the example of FIG. 3b, the coil is held on the corresponding salient pole on one side by an adjacent coil and on the other by a pole shoe 14 of the corresponding salient pole.

As a variant, the coil comprises first and second portions received in two adjacent notches, said first and second portions being situated at the same distance d1 from the axis of rotation X. This coil is held on the corresponding salient pole by the two coils adjacent.

Another coil has first and second portions received in two adjacent notches, said first and second portions being located at the same distance d2 from the axis of rotation X. This coil is held on the corresponding projecting pole by two polar openings of the two adjacent salient poles.

Thus, the rotor comprises an alternation of coils whose first and second portions are located at the same distance dl of the axis of rotation X, and coils whose first and second portions are located at the same distance d2 from the axis of rotation X.

All the coils are in this way maintained on the corresponding salient pole by an adjacent coil and / or by a polar expansion.

In the embodiment shown in Figure 4, the stator differs from that of Figure 1 by the shape of the notches 21 formed between the teeth 23 of the stator. These are of hexagonal general shape, being in diamond point. The electrical conductors in these notches are circular in cross section. The arrangement of the latter is a hexagonal arrangement. In addition, in this example, the yoke 29 is equipped with semicircular longitudinal ribs 31 intended to house conduits 30 for circulation of a cooling liquid.

The rotor coils may comprise a plurality of turns. The turns of a coil can be shifted, as shown in Figure 5, which can help promote their cooling. The cooling can also be favored by the space provided in the coils and between the coils, in the notches.

Furthermore, the machine may comprise a fan 40 disposed on the shaft at the reel heads, so as to further promote their cooling.

In the example of Figure 1, the number of poles in the rotor is 8. It is not beyond the scope of the present invention if this number is different. The machine may for example have 6 poles protruding from the rotor, as shown in Figure 6.

The rotor is obtained by means of the manufacturing process which will now be described in detail.

In a preparatory step, the coils are prepared on cores. Each coil has first and second portions to be received in rotor notches.

Then the first portion of the coil is inserted into a first notch adjacent to the first lateral face of a projecting pole, this first lateral face having the lateral pole expansion.

Finally, the second portion of the coil is inserted into a second notch adjacent to the second lateral face of the salient pole.

In particular, the first portions of all the coils are inserted into the corresponding notches at the same time, then the second portions of all the coils are inserted into the corresponding notches at a time.

Finally, the coils are shifted circumferentially, in particular so as to maintain a coil on the corresponding projecting pole by an adjacent coil and / or by a polar expansion.

The assembly obtained can be impregnated before being inserted into the stator prepared elsewhere. Of course, the invention is not limited to the embodiments which have just been described.

The phrase "with one" should be understood as synonymous with "comprising at least one".

Claims

An electric machine (10) comprising a rotor (1), rotating about an axis of rotation (X), the rotor comprising:

- projecting poles (13) between them notches (11), the salient poles each being of generally asymmetrical shape with respect to a median radial plane containing the axis of rotation (X) of the machine,

- Coils (12), each coil (12) being arranged on a corresponding projecting pole (13), in the notches adjacent to this salient pole,

and a stator (2) having teeth defining between them notches.

2. Electrical machine according to the preceding claim, wherein each projecting pole comprises a lateral pole shoe (14), in particular on a first lateral face (14a) of the projecting pole, when the rotor is observed along the axis of rotation (X). .

3. Electrical machine according to the preceding claim, said projecting pole having a second side face (14b) opposite the first side face (14a), which is devoid of polar expansion.

4. Electrical machine according to the preceding claim, the second side face (14b) extending in a plane (Z) radial or at an angle (g) with a radial plane (Z) passing through its base.

5. Electrical machine according to one of the two preceding claims, the second side face (14b) forming a non-zero angle (b) with the first side face.

6. Electrical machine according to any one of the preceding claims, the coils (12) having been inserted on the corresponding salient poles (13) after their winding.

An electrical machine according to any one of the preceding claims, wherein a coil (12) has first and second portions (12a, 12b) received in two adjacent notches, said first and second portions being respectively at distances (dl , d2) of the axis of rotation (X), the distances (d1, d2) being equal or different.

Electric machine according to any one of the preceding claims, wherein a coil (12) is held on the corresponding projecting pole by an adjacent coil and / or by a pole shoe (14).

9. Rotor (1) of electric machine, the rotor comprising:

- projecting poles (13) between them notches (11), the salient poles each preferably of generally asymmetrical shape with respect to a radial plane containing an axis of rotation (X) of the machine, better all the salient poles being in particular of asymmetrical general shape,

- Coils (12), each coil (12) being arranged on a corresponding projecting pole (13), in the notches adjacent to said projecting pole, rotor in which at least one coil comprises first and second portions (12a, 12b) received in two adjacent notches, said first and second portions (12a, 12b) being located respectively at distances (d1, d2) from the axis of rotation (X), the distances (d1, d2) being different.

An electric machine rotor (1) rotating about an axis of rotation (X), the rotor comprising:

- projecting poles (13) between them notches (11), the salient poles each being generally asymmetrical with respect to a median radial plane containing the axis of rotation (X) of the machine, each salient pole comprising a lateral polar expansion (14), when the rotor is observed along the axis of rotation (X), said projecting pole having a second lateral face (14b) opposite to the first lateral face (14a), which is devoid of polar expansion ,

- Coils (12), each coil (12) being disposed on a corresponding projecting pole (13), in the notches adjacent to this salient pole.

11. A rotary electric machine (10) comprising a rotor (1) according to claim 9 or 10 and a stator (2).

Electric machine according to any one of claims 1 to 8 and 11, the stator (2) comprising

- a toothed crown (25) having teeth (23) defining between them notches (21) open radially outwards, and

- a yoke (29) attached to the toothed crown.

13. Machine according to the preceding claim, the stator (2) having coils (22) distributed in the slots (21), including electrical conductors (28) arranged in a row in the notches (21).

A method of manufacturing a rotor (1) of an electric machine (10) according to any one of claims 2 to 8 or a rotor (1) according to claim 10, comprising the steps of:

a) preparing a coil (12) on a core, said coil having first and second portions (12a, 12b) for receiving in notches of the rotor,

b) inserting a first portion (12a) of the coil into a first notch adjacent to the first side face (14a) of a projecting pole, said first side face having a lateral pole expansion,

c) inserting a second portion (12b) of the coil into a second notch adjacent to the second side face (14b) of said projecting pole.

15. Method according to the preceding claim, wherein the first portion (12a) of the coil is held under the pole shoe (14) of the corresponding projecting pole (13) carrying the coil or in a second coil inserted later.

16. Method according to one of the two preceding claims, wherein the second portion (l2b) of the coil is maintained under the polar expansion of a projecting pole adjacent to the projecting pole carrying the coil or a second reel inserted later.

17. Method according to one of the three preceding claims, wherein the coil (12) is deformed during its insertion.

18. Method according to one of the four preceding claims, wherein the coil is displaced during its insertion, in particular circumferentially, so as to maintain it under a polar expansion.

The method of any one of claims 14 to 18, comprising the steps of:

i) inserting the first portions (12a) of all the reels at a time in the corresponding notches, then

ii) inserting the second portions (12b) of all the reels at a time into the corresponding notches,

iii) the coils (12) are shifted circumferentially, in particular so as to maintain a coil on the corresponding projecting pole (13) by an adjacent coil and / or by a polar expansion.