STATOR FOR A ROTARY ELECTRIC MACHINE

Abstract

A stator (2) for a rotary electric machine (1), comprising:—a radially interior ring (25) comprising teeth (23) and slots (21) opening radially towards the outside and extending between the teeth, bridges of material (27) connecting two adjacent teeth to their base and defining the bottoms of the slots between these teeth,—coils (22) arranged in the slots, having electrical conductors arranged in an ordered fashion in the slots (21), and—a radially outer yoke (29) attached in contact with the ring, the yoke being formed of assembled sectors (30).

Claims

1. A stator for a rotary electric machine, comprising: a radially interior ring comprising teeth and slots opening radially towards the outside and extending between the teeth, bridges of material connecting two adjacent teeth at their base and defining the bottom of the slot between these teeth, coils arranged in the slots, having electrical conductors arranged in an ordered fashion in the slots, and a radially outer yoke attached in contact with the ring, the yoke being formed of assembled sectors, the stator comprising an axial stack of axially assembled sectors, a first interface defined between two adjacent sectors located at a first abscissa along the axis of rotation of the machine being angularly offset with respect to a second interface defined between two adjacent sectors located at a second abscissa along the axis of rotation, which abscissa is different from the first abscissa.

2. The stator according to claim 1, the sectors of the yoke each having an angular extent of between 18 and 180°, preferably between 24 and 120°, indeed between 30 and 90°.

3. The stator according to claim 1, the yoke comprising, in cross section, between 2 and 20 sectors, preferably between 3 and 15 sectors.

4. The stator according to claim 1, two adjacent sectors of the yoke defining, therebetween, an interface extending in a substantially radial plane.

5. The stator according to the claim 1, the radial plane of the interface passing through a slot, preferably all the radial planes of all the interfaces of the yoke passing through the slots.

6. The stator according to claim 1, the angular offset being between one and ten teeth, preferably between two and eight teeth.

7. The stator according to claim 1, the sectors of the yoke comprising surface reliefs which make it possible to clip them together.

8. The stator according to claim 1, the ring and the yoke comprising, respectively, first and second reliefs which cooperate with one another and/or with one or more inserts.

9. The stator according to claim 8, the bridges of material comprising zones which are magnetically saturated during the operation of the machine, in particular zones of smaller width.

10. The stator according to claim 1, the coils each comprising at least one electrical conductor which is rectangular in cross section, the coils in particular being arranged in a distributed manner in the slots.

11. A rotary electric machine comprising the stator according to claim 1, and a rotor.

12. A method for producing a stator according to claim 1, wherein sectors are attached radially on the ring to form the yoke in contact with the ring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0160] The claimed invention will be better understood upon reading the following detailed description of non-limiting embodiments thereof, and upon studying the accompanying drawing, in which:

[0161] FIG. 1 is a partial schematic perspective view of a stator,

[0162] FIG. 2 is a partial schematic perspective view of the ring of the stator of FIG. 1,

[0163] FIG. 3 is a detailed view thereof,

[0164] FIG. 4 is a partial schematic cross-sectional view of a machine comprising the stator of FIG. 1,

[0165] FIG. 5 is a schematic view of a portion of the ring of said stator,

[0166] FIG. 6 is a schematic perspective view of a variant of the machine,

[0167] FIG. 6a is a detailed view thereof,

[0168] FIG. 7a is a view analogous to FIGS. 6 and 6a, of a variant,

[0169] FIG. 7b is a view analogous to FIGS. 6 and 6a, of a variant,

[0170] FIG. 7c is a view analogous to FIGS. 6 and 6a, of a variant,

[0171] FIG. 7d is a view analogous to FIGS. 6 and 6a, of a variant,

[0172] FIG. 8 is a schematic view of a variant of the machine,

[0173] FIG. 9 is a detailed view thereof,

[0174] FIG. 9a is a view analogous to FIG. 9, of a variant,

[0175] FIG. 10 is a partial schematic cross-sectional view of a sector of the yoke of FIG. 8,

[0176] FIG. 11 is a view analogous to FIG. 10, of a variant,

[0177] FIG. 12 is a view analogous to FIG. 10, of a variant,

[0178] FIG. 13 is a view analogous to FIG. 9, of a variant,

[0179] FIG. 14 is a view analogous to FIG. 8, of a variant,

[0180] FIG. 15 is a view analogous to FIG. 9, of the variant of FIG. 14,

[0181] FIG. 16a is a view analogous to FIG. 10, of a variant,

[0182] FIG. 16b is a partial schematic perspective view of the ring associated with the yoke sector of FIG. 16a,

[0183] FIG. 17a is a view analogous to FIG. 9, of another variant,

[0184] FIG. 17b is a view analogous to FIG. 9, of another variant,

[0185] FIG. 17c is a view analogous to FIG. 9, of another variant,

[0186] FIG. 17d is a view analogous to FIG. 9, of another variant,

[0187] FIG. 17e is a view analogous to FIG. 9, of another variant.

DETAILED DESCRIPTION

[0188] FIGS. 1 to 5 show a rotary electric machine 10 comprising a rotor 1 and a stator 2. The stator 2 makes it possible to generate a rotating magnetic field for causing the rotor 1 to rotate, in the context of a synchronous motor, and in the case of an alternator the rotation of said rotor induces an electromotive force in the coils of the stator.

[0189] The examples illustrated below are schematic, and the relative dimensions are not necessarily respected.

[0190] The stator 2 comprises coils 22, which are arranged in slots 21 provided between teeth 23 of a radially interior toothed ring 25. The slots are open radially towards the outside and closed on the side of the air gap by bridges 27 of material, each connecting two adjacent teeth of the ring 25 and defining the bottom of the slot between these teeth.

[0191] In the example described, the slots 21 have mutually parallel radial edges 33 and are substantially rectangular in shape in a cross section in a plane perpendicular to the axis of rotation X of the machine.

[0192] The stator 2 comprises a radially outer yoke 29 and is attached in contact with the ring 25. The ring 25 and the yoke 29 are each formed of a pack of magnetic sheets stacked along the X axis, the sheets being for example identical and exactly superposed. They can be held together by clipping, by rivets, by tie rods, by welds, and/or any other technique. The magnetic sheets are preferably made of magnetic steel.

[0193] The yoke 29 is formed of assembled sectors 30, of which there are six in the example described. Each sector 30 is attached in contact with the ring 25. They are assembled together and on the ring during the production of the stator.

[0194] In the example described, each sector has an angular extent of 60°, measured in a transverse plane of the stator, perpendicular to an axis of rotation of the machine, around said axis of rotation. Each sector 30 has the same angular extent.

[0195] The sectors 30 of the yoke are also identical to one another in shape.

[0196] Each sector cooperates with six teeth of the ring 25.

[0197] Finally, in the example described, two adjacent sectors 30 of the yoke define, therebetween, an interface 30a extending entirely in a radial plane. Said interface 30a is planar.

[0198] The radial planes of the interfaces 30a pass through the corresponding slots, in particular in the center thereof.

[0199] Furthermore, in the example shown, the teeth 23 of the ring 25 comprise complementary surface reliefs 56 which make it possible to clip together the different sheets which make up the ring 25, as can be seen in FIG. 5.

[0200] The ring may furthermore be formed of a strip of sheet metal that is coiled up on itself.

[0201] The yoke 29 is mounted interlockingly on the ring 25, more particularly the sectors 30 of the yoke 29 are mounted interlockingly on the ring 25. For this purpose, the ring 25 and the yoke 29 comprise, respectively, first 40 and second 50 reliefs which cooperate so as to immobilize the yoke 29 with respect to the ring 25. Said first 40 and second 50 reliefs allow for angular and radial immobilization.

[0202] The first reliefs 40 are located on the outer surface of the ring 25, being arranged on the teeth, at the end thereof facing the yoke.

[0203] The second reliefs 50 are located on the inner surface of the yoke 29, opposite the teeth of the ring and more particularly opposite the first reliefs. They are angularly offset with respect to the slots of the ring.

[0204] The first 40 and second 50 reliefs are complementary and cooperate interlockingly and so as to keep the ring and the yoke in position relative to one another.

[0205] The coils 22 may be arranged in a concentrated or distributed manner in the slots 21, preferably in a distributed manner. As shown in FIG. 5, the electrical conductors 34 of the coil 22 are arranged in the slots in an ordered fashion. The electrical conductors 34 preferably have a flattened, rectangular cross section, and are radially superposed for example in a single row. The electrical conductors 34 are enameled or coated with any other suitable insulating coating.

[0206] Each slot 21 can receive two stacked coils 22 of different phases. Each coil 22 may be substantially rectangular in shape, in cross section.

[0207] Each coil 22 is surrounded by an insulating sheet 37 which makes it possible to insulate the coils from the walls 33 and 36 of the slot and the coils 22 of different phases.

[0208] The electrical conductors 34 are assembled in coils 22 outside the slots 21 and surrounded by an insulating sheet 37 and the coils 22 comprising the insulating sheets 37 are inserted into the slots 21. This operation is facilitated by the fact that the slots are entirely open radially towards the outside.

[0209] The rotor 1 shown in FIG. 4 comprises a central opening 5 for mounting on a shaft, and comprises a magnetic rotor mass 3 extending axially in the axis of rotation X of the rotor, said rotor mass being formed for example by a pack of magnetic sheets stacked according to the X axis, the sheets being for example identical and exactly superposed. The rotor 1 comprises, for example, a plurality of permanent magnets 7 arranged in the recesses 8 of the magnetic rotor mass 3. In a variant, the rotor is coiled.

[0210] The stator may be obtained by means of the production method which will now be described. The coils 22 are first inserted into the slots 21 of the ring 25 by a radial displacement of the coils 21 towards the inside of the slots 21. In a following step, the yoke 29 is attached by force to the ring 27, all the sectors 30 being radially attached simultaneously, in a radial direction extending in the mid-plane of the corresponding sector. Each sector may be inserted onto the ring by axial displacement of one relative to the other, as shown in FIG. 1.

[0211] In a variant shown in FIGS. 6 and 6a, the interface between the yoke and the ring forms undulations 99. For this purpose, the first reliefs 40 are in the shape of a boss, and the second reliefs 50 are in the shape of a corresponding recess. In the example described, the second reliefs 50 have an angular opening α of the order of 80°.

[0212] In the example described, each sector has the same angular extent, measured in a transverse plane of the stator, perpendicular to an axis of rotation of the machine, around said axis of rotation, allowing it to cooperate with five teeth of the ring. In this example, the yoke 29 comprises nine sectors 30 which are also identical to one another in shape. Each sector cooperates with five teeth of the ring 25.

[0213] Two adjacent sectors of the yoke define, therebetween, an interface extending in part in a substantially radial plane, but not entirely, the sectors comprising reliefs 110 intended to cooperate with corresponding reliefs of the other adjacent sector.

[0214] In this example of FIG. 6, the stator comprises an axial stack of sectors 30 which are assembled axially. A plurality of consecutive sectors are encountered when moving in parallel with the axis of rotation X of the machine.

[0215] A first interface 30a defined between two adjacent sectors 30 located at a first abscissa X1 along the axis of rotation of the machine may be angularly offset with respect to a second interface 30a defined between two adjacent sectors 30 located at a second abscissa X2 along the axis of rotation, which abscissa is different from the first abscissa X1. Furthermore, said second interface 30a is located circumferentially between the first interface 30a and a third interface 30a located at the same first abscissa X1.

[0216] In the embodiment shown in FIG. 6, the outer surface of the sectors 30 is smooth.

[0217] In a variant shown in FIGS. 7 and 7a, the outer surface of the sectors 30 comprises grooves 30b which form a continuation of one another when the sectors are stacked to form the yoke of the stator, thus forming grooves on the outer surface of the yoke. In this embodiment, each sector comprises two grooves. In said embodiment, the sectors are “reversed,” every other sheet.

[0218] In a variant shown in FIG. 7b, each sector comprises a single groove 30b. When the sectors are assembled together, it is necessary to drill in order to pass a hard spot, which makes it possible to ensure the coherency of the assembly. The embodiment of FIGS. 7c and 7d differs from the preceding embodiments by the fact that it does not comprise stacked sectors when moving in parallel with the axis of rotation X of the machine. In this example, the yoke is formed of sectors 30 assembled circumferentially and not axially.

[0219] In the variant shown in FIGS. 8 to 10, the interface between the yoke and the ring also forms undulations 99. For this purpose, the first reliefs 40 are in the shape of a boss, and the second reliefs 50 are in the shape of a corresponding recess. In the example described, the second reliefs 50 have an angular opening α of 80°.

[0220] In the example described, each sector has an angular extent β of 72°, measured in a transverse plane of the stator, perpendicular to an axis of rotation of the machine, around said axis of rotation. Each sector 30 has the same angular extent.

[0221] In this example, the yoke 29 comprises five sectors 30 which are also identical to one another in shape. Each sector cooperates with nine teeth of the ring 25.

[0222] Furthermore, in the example shown, the teeth 23 of the ring 25 comprise complementary surface reliefs 56 which make it possible to clip together the different sheets which make up the ring 25, as can be seen in FIG. 9. In this example of FIG. 9, a complementary relief 56 is present on each tooth. Of course, it would not be a departure for every other tooth to comprise such complementary reliefs, or one tooth in three, or in four, for example. The yoke can also comprise these, as shown in FIG. 8.

[0223] Said reliefs 56 can be generally oblong in shape, for example rectangular, and they may have a major axis oriented radially, or, in a variant, oriented circumferentially, as shown in FIG. 11.

[0224] The stator may be obtained by means of the production method which will now be described. Following insertion of the coils 22 into the slots 21 of the ring 25 by a radial displacement of the coils 21 towards the inside of the slots 21, all the sectors 30 of the yoke 29 are radially attached simultaneously, according to a radial direction extending in the median plane of the corresponding sector. Each sector may be inserted onto the ring by radial, and not axial, displacement of one relative to the other, by virtue of the planar shape of the interfaces 30a between the sectors 30 and the rippled shape of the interface between the yoke and the ring.

[0225] The angular extent of each sector, the shape of the interfaces 30a, and the shape of the interface between the yoke and the ring are selected so as to allow the sectors 30 of the yoke to move closer, radially, on the ring. In one embodiment they are attached simultaneously.

[0226] In the example described with reference to FIGS. 1 to 5, the bottom 35 of the slots 21 is of a shape substantially complementary to that of the coils 22, being planar.

[0227] In a variant, the bottom of the slots 35 may comprise a localized narrowing formed by at least one groove, as shown in FIG. 9, and in the embodiments of FIGS. 7 to 7d. In this example, the bottom 35 of the slots 21 comprises two planar portions 31 on either side of a recess 39, against which the rectangular coils 22 come to bear. The bottom 35 of the slots 21 is connected to the radial edges 33 by rounded edges 36. The recess 39 is provided in the form of a longitudinal groove extending along the axis of rotation X of the machine, centered on the bottom of the slot 21.

[0228] The recess 39 preferably has a depth p of between 0.4 mm and 1 mm, for example 0.6 mm.

[0229] In another variant shown in FIG. 9a, the bottom of the slot 21 may not comprise a recess, the bottom 35 of the slots being flat.

[0230] In another variant, the bottom of the slot 21 may not comprise a recess, and the pleats may each be formed of a groove turned towards said bottom of the slot 21, and a projecting relief may extend into the air gap 46.

[0231] The grooves 48 and projecting reliefs 42 may have a profile in the form of a V-shaped broken line, and the bottom of the slot 21 has a width which reduces towards the projecting relief from the radial edges 33 of the slot 21.

[0232] The deformable zone is a zone which may stretch and deform by stretching to form a constriction. When it is stretched, the deformable zone 32 may become thinner locally. Prior to the mounting of the yoke, the bridge of material 27 may have a constant thickness.

[0233] The bottom of the slot may comprise two deformable zones 32 as described above.

[0234] In this example of FIGS. 8 to 10, the interface between two adjacent sectors 30 is planar, extending in a radial plane.

[0235] Two adjacent sectors of the yoke may define, therebetween, an interface extending almost entirely in a substantially radial plane, but not entirely, as shown in FIG. 12. In this example, the sectors comprise reliefs 110 intended to cooperate with corresponding reliefs of the other adjacent sector. The reliefs 110 comprise a triangular part 110a which cooperates in an interlocking manner with the adjacent sector, and a circular part 110b forming an orifice between the two adjacent sectors.

[0236] The embodiment of FIG. 13 differs from that of FIGS. 8 to 10 in that the slots of the ring comprise rounded corners 92 close to the yoke.

[0237] Holes 100 may be arranged at the interface between the ring and the yoke, as shown in FIGS. 14 and 15. These holes 100 make it possible to avoid the presence of sharp edges in the region of the interface. There is a maximum contact between the straight edges on either side of the holes 100.

[0238] These holes 100 may serve for passage of a flow of cooling fluid, for example a flow of air, for the cooling of the stator. In a variant, they may serve for passage of tie rods for holding the stator.

[0239] In this embodiment, each sector has an angular extent of 60°, measured in a transverse plane of the stator, perpendicular to an axis of rotation of the machine, around said axis of rotation. Each sector 30 has the same angular extent. The sectors 30 of the yoke are also identical to one another in shape. Each sector cooperates with eight teeth of the ring 25.

[0240] In the variant shown in FIGS. 16a and 16b, the sector of the yoke comprises second reliefs 50, the bottom of which is in the shape of a circular arc. In the example described, the bottom of every other second relief 50 is deeper than the others. Furthermore, every other tooth of the toothed ring shown in FIG. 16b is also longer. There is thus an alternation of two depths at the interface between the yoke and the ring.

[0241] Furthermore, at least two sets of sheets, one of which is reversed with respect to the other, are put in place in the pack of sheets. There is thus a resulting offset in the region of the interface I between the assemblies, as can be seen in FIG. 16b.

[0242] In a variant, it is also possible to offset the interior ring by one tooth pitch, without forming the reversal.

[0243] Thus, when the sectors of the yoke are in place on the toothed ring, an axial blocking due to the presence of said offset is achieved.

[0244] Furthermore, said interface I makes it possible to firmly immobilize the toothed ring with respect to the yoke.

[0245] The interface I between the assemblies may be located in the center of the pack of sheets, or, in a variant, offset on one side.

[0246] Other variants will now be set out.

[0247] In the embodiment of FIG. 9, the second relief is oriented towards the yoke.

[0248] In another embodiment shown in FIG. 17a, the second relief is, in contrast, oriented towards the air gap.

[0249] In another embodiment shown in FIG. 17b, the second relief is flat. The angular opening α is α=180°.

[0250] In a variant shown in FIG. 17c, the second reliefs have a contour formed of two straight portions forming an angle α therebetween, comprising, on either side, two flat portions at 180°. A point is thus formed for stopping the rotation of the yoke relative to the ring. The point may be oriented towards the yoke, or, in a variant, towards the air gap.

[0251] In another variant, as shown in FIGS. 17d and 17a, the second reliefs may have a contour in the shape of a circular arc. The circular arc has a chord separated by a distance h from its center of curvature. The following relationship exists:

|N|≥r.Math.sin(β/2−π/Nenc),

where r is the radius of curvature of the circular arc portion, h is the distance separating the chord of the circular arc from the center of curvature, β is the angular extent of a sector of the yoke, and Nenc is the total number of slots of the stator.

[0252] The circular arc may be oriented towards the yoke, as shown in FIG. 17d, or, in a variant, towards the air gap, as shown in FIG. 17e.

[0253] The claimed invention is not limited to the described examples of the interface between the sectors of the yoke, and this can be implemented with different shapes again.