STATOR FOR A ROTATING ELECTRICAL MACHINE

Abstract

A stator including a ring having teeth and slots between said teeth that open radially outwards and material bridges, each linking two adjacent teeth to the respective base on the side of the air-gap, a yoke attached to the ring, and windings placed in the slots of the ring, at least some of the material bridges having at least on deformable zone that can be deformed during assembly of the yoke on the ring.

Claims

1. A stator comprising: a ring comprising: teeth and slots that open radially outwards between said teeth, and material bridges, each linking two adjacent teeth to the respective base on the side of the air-gap, a yoke attached to the ring, and windings placed in the slots of the ring, at least some of the material bridges having at least one deformable zone that can be deformed during assembly of the yoke on the ring.

2. The stator as claimed in claim 1, in which each material bridge has at least one deformable zone.

3. The stator as claimed in claim 1, wherein each deformable zone is a corrugation forming at least one groove on one of the sides of the material bridge and a projecting relief on the opposite side.

4. The stator as claimed in claim 3, wherein the projecting relief or reliefs extend into a recess in the bottom of the corresponding slot.

5. The stator as claimed in claim 3, wherein the grooves open towards the air-gap and the projecting relief or reliefs extend into the bottom of the corresponding slot.

6. The stator as claimed in claim 1, wherein each material bridge has a deformable zone with a center line having a curved profile or in the form of a broken line when the stator is viewed along the rotation axis.

7. The stator as claimed in claim 1, wherein the deformable zone is a zone of the material bridge that can be stretched and deformed by stretching to form a constriction during assembly of the yoke on the ring and/or during insertion of the windings in the slots.

8. The stator as claimed in claim 1, wherein the deformable zones are zones of the material bridge that are saturated magnetically during operation of the machine.

9. The stator as claimed in claim 1, wherein each of the slots has at least one flat portion against which bears a winding.

10. The stator as claimed in claim 1, wherein the ring has reliefs on the radially external surface thereof that cooperate with the cooperating reliefs of the yoke.

11. The stator as claimed in claim 1, wherein each of the windings has at least one electrical conductor with a rectangular cross section.

12. The stator as claimed in claim 1, wherein each slot receives two windings of different phases.

13. A rotating electrical machine including a stator as claimed in claim 1 and a rotor.

14. A manufacturing method for a stator as claimed in claim 1 comprising a step of deforming the deformable zone or zones during assembly of the yoke on the ring and/or insertion of the windings in the slots.

15. The method as claimed in claim 14, wherein a step of inserting the windings in the slots is performed to widen the slots by extending the material bridges.

16. The method as claimed in claim 14, wherein a step of assembling the yoke on the ring reduces a diameter of the ring by compressing the material bridges.

17. The method as claimed in claim 16, further comprising a step of cutting the ring and the yoke simultaneously from the same sheet by means of one or more common cuts.

18. The stator as claimed in claim 4, wherein the projecting relief or reliefs are of height h equal to or less than the depth p of the recess.

Description

DETAILED DESCRIPTION

[0077] The invention is further explained in the detailed description given below of non-limiting example embodiments of the invention and the attached drawings, in which:

[0078] FIG. 1 is a schematic partial cross section of a machine including a stator according to the invention,

[0079] FIG. 2 is a schematic view of a portion of the ring of the stator of the machine in FIG. 1,

[0080] FIG. 3 shows a portion of the ring of the stator in FIG. 2, in which the deformable zones are enlarged,

[0081] FIG. 4 shows the portion of the ring of the stator in FIG. 2, in which the deformable zones are compressed,

[0082] FIGS. 5 to 7 show variants in the form of the material bridges and slots,

[0083] FIG. 8 shows a variant portion of the ring of the stator, in which the deformable zones are enlarged,

[0084] FIG. 9 shows the portion of the ring of the stator in FIG. 8, in which the deformable zones are compressed, and

[0085] FIGS. 10 to 13 show variant portions of the ring of the stator.

[0086] FIG. 1 shows a rotating electrical machine 10 with a rotor 1 and a stator 2. The stator is used to generate a rotary magnetic field to drive the rotor 1 as part of a synchronous motor and, in the case of an alternator, the rotation of the rotor induces an electromotive force in the windings of the stator.

[0087] The examples illustrated below are schematic and the relative dimensions are not necessarily respected.

Stator

[0088] The stator 2 has windings 22 that are arranged in the slots 21 formed between the teeth 23 of an indented ring 25. The slots are closed on the side of the air-gap by material bridges 27, each linking two consecutive teeth of the ring 25.

[0089] The stator 2 has a yoke 29 attached to the ring 25.

[0090] In the example described, the slots 21 have parallel radial edges 33 and have a substantially rectangular section in a plane perpendicular to the rotation axis X of the machine.

[0091] The bottom of the slots 35 fits the shape of the windings 22, with the exception of a recess 40. In the example in FIGS. 1 to 4, the bottom of the slots 35 has two flat portions 30 on either side of the recess 40 against which the rectangular windings 22 bear. The bottom of the slots 35 is joined to the radial edges 33 by rounded edges 36.

[0092] The recess 40 is a longitudinal groove extending along the rotation axis X of the machine, centered on the bottom of the slot 21.

[0093] The recess 40 preferably has a depth p of between 0.4 mm and 1 mm, for example 0.6 mm.

[0094] Each of the material bridges 27 preferably has a deformable zone 32 that enables the circumference e thereof, which is the width of the slots 21, to be varied, thereby varying the mean internal diameter 2R of the ring 25.

[0095] In the example shown, the deformable zones 32 are corrugations.

[0096] The material bridges 27 are of variable width, and the deformable zones 32 are the narrowest zones. The narrowest point of the material bridges 27 is preferably between 0.3 mm and 0.6 mm, for example 0.4 mm.

[0097] As shown in FIG. 2, each corrugation forms a projecting relief 42 that extends into the recess 40 on the side of the bottom of the slots 35, and a groove 48 on the side of the air-gap 46.

[0098] Each projecting relief 42 forms a rib with a rounded apex. The height h of the relief is less than the depth p of the recess 40 so as not to exceed the latter.

[0099] The grooves 48 are channels of rounded section in a plane perpendicular to the axis X.

[0100] As shown in FIG. 3, when the deformable zones 32 are stretched, the grooves 48 and projecting reliefs 42 are flattened, thereby elongating the material bridge and enlarging the slot.

[0101] As shown in FIG. 4, when the ring 25 is compressed, the grooves 48 and the projecting reliefs 42 fold up. The height h.sub.max of the projecting reliefs 42 is greater than the height h with no deformation and the depth p.sub.max of the deformations 40 is greater than the depth p with no deformation, the height h.sub.max being less than the depth p.sub.max of the corresponding recess 40.

[0102] The ring 25 and/or the yoke 29 are each formed by a packet of magnetic sheets stacked along the axis X, the sheets being for example identical and exactly superposed. The sheets can be held together by snap-fitting, rivets, ties, welding and/or any other technique. The magnetic sheets are preferably made of magnetic steel.

[0103] In the example illustrated, the teeth 23 of the ring 25 have matching surface reliefs 56 enabling the different sheets making up the ring 25 to be snap fitted together. The matching reliefs 56 can be on all of the teeth 23 or only on some of the teeth 23, for example on every other tooth 23.

[0104] In a variant, the sheets are bonded together or assembled in another manner.

[0105] Similarly, the yoke 29 can have matching surface reliefs to snap fit the different sheets making up the yoke 29 together. The ring and/or the yoke can also be formed from a strip of cut sheet wound about itself.

[0106] The yoke 29 is mounted on the ring 25 in a form-fitting manner. The ring 25 and the yoke 29 have matching reliefs 49 on the outer surface of the ring and the inner surface of the yoke, enabling these elements to be held in position in relation to one another.

Windings

[0107] The windings 22 can be arranged in the slots 21 in a concentrated or distributed manner, preferably distributed.

[0108] In the example shown in FIG. 2, the electrical conductors 34 of the windings 22 are arranged in rows in the slots.

[0109] As illustrated in FIG. 2, the electrical conductors 34 preferably have a flat rectangular cross section and are superposed radially for example in a single row. The electrical conductors 34 are enameled or coated with any other suitable insulating coating.

[0110] Each slot 21 can receive two stacked windings 22 of different phases. Each winding 22 can have a substantially rectangular cross section.

[0111] Each winding 22 is wrapped in an insulating sheet 37 to insulate the windings from the walls 33 and 36 of the slot and the windings 22 of different phases.

[0112] The electrical conductors 22 are assembled in windings 22 outside the slots 21 and wrapped in an insulating sheet 27 and the windings 22 with the insulating sheets 37 are inserted into the slots 21. This operation is facilitated by the fact that the slots are open fully and radially outwards, and by the fact that the material bridges are deformable.

Rotor

[0113] The rotor 1 shown in FIG. 1 has a central opening 5 for assembly on the shaft and has a magnetic rotor mass 3 extending axially along the rotation axis X of the rotor, this rotor mass being for example formed by a packet of magnetic sheets stacked along the axis X, the sheets being for example identical and exactly superposed.

[0114] The rotor 1 for example has a plurality of permanent magnets 7 arranged in the seats 8 of the magnetic rotor mass 3. In a variant, the rotor is wound.

Manufacturing Method for the Stator and Machine

[0115] The stator can be obtained using the manufacturing method described below.

[0116] The windings 22 are inserted into the slots 21 of the ring 25 by means of a radial movement of the windings 21 towards the inside of the slots 21. During insertion of the windings 22, the slots 21 can be enlarged by deformation of the deformable zones of the material bridges 27. The external diameter of the ring 25 can therefore be greater than before winding.

[0117] In the following step, the yoke 29 is securely attached to the ring 27. This assembly can result in a reduction of the enlarged external diameter of the ring 25 by deformation of the deformable zones 32. The clearance between the ring and the yoke is then minimal.

[0118] The embodiment in FIG. 5 differs from the embodiment in FIGS. 1 and 2 in that the bottom of the slot 21 has no recess. The projecting reliefs have a rounded section in a plane perpendicular to the axis X.

[0119] The embodiment in FIG. 6 differs from the embodiment in FIGS. 1 and 2 in that the bottom of the slot 21 has no recess and in that each of the corrugations is formed by a groove 50 oriented towards this bottom of the slot 21 and a projecting relief 52 extending into the air-gap 46.

[0120] The embodiment in FIG. 7 differs from the embodiment in FIG. 5 in that the profile of the grooves 48 and of the projecting reliefs 42 is a V-shaped broken line, and in that the bottom of the slot 21 decreases in width towards the projecting relief from the radial edges 33 of the slot 21.

[0121] The embodiment in FIGS. 8 and 9 differs from the embodiment in FIGS. 1 and 2 in that the deformable zone is a zone that can be stretched and deformed by stretching to form a constriction 60. When stretched, as shown in FIG. 8, the deformable zone 32 can narrow locally. Before assembly of the yoke, the thickness of the material bridge 27 can be constant, as shown in FIG. 9.

[0122] The embodiment in FIG. 10 differs from the embodiment in FIGS. 1 and 2 in that the bottom of the slot has two deformable zones 32 as described above.

[0123] The embodiments in FIGS. 11 to 13 differ from the embodiment in FIGS. 1 and 2 in that at least some of the material bridges 27 have matching reliefs 62 and 64. These matching reliefs 62 and 64 can be in a zone of the material bridge 27 other than the deformable zone 32. In these embodiments, the ring 25 is made by assembly of the sheet metal sectors that are assembled together circumferentially by means of the matching reliefs 62 and 64. The matching reliefs 62 and 64 can be matching reliefs that are fastened together, such as dovetails and mortises, as shown in FIG. 11. This enables two sectors to be fastened together with the ring extended or compressed. In a variant, as shown in FIGS. 12 and 13, the matching reliefs 62 and 64 are respectively projecting and recessed reliefs with matching shapes that bear against one another without the reliefs 62 and 64 being fastened to one another, by compression of the ring 25, notably by the yoke 29. This enables two sectors to be held adjacent by engagement of the reliefs 62 and 64 and by pressing the reliefs 62 and 64 against one another while compressing the ring.

[0124] Naturally, the invention is not limited to the example embodiments described above, and the deformable zones need not be centered.

[0125] The invention is not limited to the example material bridges illustrated, and these latter can be made in other forms, for example with multiple corrugations.

[0126] The expression including one should be understood to mean the same as including at least one.