STATOR FOR A ROTATING ELECTRICAL MACHINE

Abstract

A method for manufacturing a stator of an electrical machine. The method including: a toothed ring having teeth joined together by bridges of material and defining between them slots open radially toward the outside, windings produced outside of the slots, and a yoke configured to be attached to the toothed ring. The method also including attaching at least one piece of sheet-form insulation to at least a portion of each of the windings, inserting said winding portions with the insulation into the slots via a radial movement directed toward the inside of the slots, and assembling the yoke onto the radially exterior surface of the ring to close the slots radially.

Claims

1. A method for manufacturing a stator of an electrical machine, the method employing: a toothed ring comprising teeth joined together by bridges of material and defining between them slots open radially toward the outside, the slots having mutually parallel opposing edges, windings produced outside of the slots, and a yoke configured to be attached to the toothed ring, the method comprising: attaching at least one piece of sheet-form insulation to at least a portion of each of the windings, the pieces of sheet-form insulation extending over rectilinear winding portions, inserting said winding portions with the insulation into the slots via a radial movement directed toward the inside of the slots, and assembling the yoke onto the radially exterior surface of the ring to close the slots radially.

2. A method for manufacturing a stator of an electrical machine, the method employing: a toothed ring comprising teeth joined together by bridges of material and defining between them slots open radially toward the outside, windings produced outside of the slots, the windings each comprising at least one electrical conductor which, in transverse section, is rectangular, wound on edge, and a yoke configured to be attached to the toothed ring, the method comprising: attaching at least one piece of sheet-form insulation to at least a portion of each of the windings, inserting said winding portions with the insulation into the slots via a radial movement directed toward the inside of the slots, and assembling the yoke onto the radially exterior surface of the ring to close the slots radially.

3. A method for manufacturing a stator of an electrical machine, the method employing: a toothed ring comprising teeth joined together by bridges of material and defining between them slots open radially toward the outside, windings produced outside of the slots, and a yoke configured to be attached to the toothed ring, the method comprising: attaching at least one piece of sheet-form insulation to at least a portion of each of the windings over the entire height of the slots, the sheet-form insulation being of a height substantially equal to the height of the slots, inserting said winding portions with the insulation into the slots via a radial movement directed toward the inside of the slots, and assembling the yoke onto the radially exterior surface of the ring to close the slots radially.

4. A method for manufacturing a stator of an electrical machine, the method employing: a toothed ring comprising teeth joined together by bridges of material and defining between them slots open radially toward the outside, windings produced outside of the slots, and a yoke configured to be attached to the toothed ring, the method comprising: attaching at least one piece of sheet-form insulation to at least a portion of each of the windings, the pieces of sheet-form insulation each comprising two opposing longitudinal edges extending substantially along the longitudinal axis of the associated winding portion, the winding portions being rectangular in transverse section and the two opposing longitudinal edges of each piece of sheet-form insulation extending over the one same face of the corresponding winding portion, inserting said winding portions with the insulation into the slots via a radial movement directed toward the inside of the slots in such a way that the longitudinal edges of the corresponding sheet-form insulation extend over a face of the winding portion that is oriented toward the opening of the slot, or toward a portion of a winding inserted in that same slot, and assembling the yoke onto the radially exterior surface of the ring to close the slots radially.

5. The method as claimed in claim 1, wherein once the windings with the insulation have been inserted into the slots, the insulation extends in each slot over the entire height of the slot.

6. The method as claimed in claim 5, the pieces of sheet-form insulation protruding axially out of the slots on each side of the latter after insertion.

7. The method as claimed in claim 1, the pieces of sheet-form insulation each comprising two opposing longitudinal edges extending substantially along the longitudinal axis of the associated winding portion, the winding portions being rectangular in transverse section and the two opposing longitudinal edges of each piece of sheet-form insulation extending over the one same face of the corresponding winding portion.

8. The method as claimed in claim 7, the longitudinal edges of each piece of sheet-form insulation being in contact with one another on said face.

9. The method as claimed in claim 7, each piece of sheet-form insulation becoming at least partially superposed on itself.

10. The method as claimed in claim 7, each winding portion being placed in the corresponding slot in such a way that the longitudinal edges of the corresponding piece of sheet-form insulation extend over a face of the winding portion that is oriented toward the opening of the slot or toward a portion of a winding.

11. The method as claimed in claim 1, the sheet-form insulation taking the form of a tape wound around the winding portion.

12. The method as claimed in claim 1, wherein the pieces of sheet-form insulation are secured to the windings over at least part of their surface.

13. The method as claimed in claim 1, wherein each piece of sheet-form insulation is secured to the winding portion at least at one of its longitudinal ends, using adhesive bonding on all or part of the piece of sheet-form insulation and/or on all or part of the corresponding winding portion, or using at least one adhesive tape, for example straddling the sheet-form insulation and the winding portion.

14. The method as claimed in claim 1, each winding portion being covered with a single piece of sheet-form insulation.

15. The method as claimed in claim 1, each winding portion being covered with at least two pieces of sheet-form insulation superposed with one another at least in part or with touching edges.

16. The method as claimed in claim 1, wherein the winding portions that are inserted into the slots are separated from the interior walls of the slot by at least one thickness of the insulation.

17. The method as claimed in claim 1, the winding being of substantially rectangular cross section, the step of securing the sheet-form insulation to each of the winding portions comprising the following substeps: laying the piece of sheet-form insulation out flat, positioning a first face of the winding on the sheet-form insulation by applying a pressure to the winding portion in contact with the piece of sheet-form insulation opposite to the first face, in order to maintain contact between the sheet-form insulation and the first face of the winding, applying the two free sides of the piece of sheet-form insulation to two opposite lateral faces of the winding, folding one of the free flaps of the piece of sheet-form insulation onto the second face then folding the remaining free flap of the piece of sheet-form insulation onto the second face, the piece of sheet-form insulation having a width, with respect to the corresponding winding, that is such that its ends become superposed with the second face, and applying a pressure to the second face of the winding wrapped in sheet-form insulation, the substeps being performed using a suitable folding device comprising flap-folding wings able to fold the piece of sheet-form insulation against the third faces, slides able to fold the two flaps of the piece of sheet-form insulation onto the second face and a retaining tool able to hold the winding in position and apply pressure to the second face of the winding.

18. The method as claimed in claim 1, wherein, during the step of inserting the winding portions, each slot accepts at least two winding portions.

19. The method as claimed in claim 18, wherein the two winding portions in the same slot are separated from one another by at least one thickness of the sheet-form insulation.

20. The method as claimed in claim 1, each winding portion being placed in the corresponding slot in such a way that the longitudinal edges of the corresponding piece of sheet-form insulation extend over a face of the winding portion that is oriented toward the other winding portion.

21. The method as claimed in claim 1, the sheet-form insulation being made of a flexible electrically insulating material.

22. The method as claimed in claim 1, the pieces of sheet-form insulation extending only over rectilinear winding portions.

23. A stator comprising: a radially interior ring, comprising: teeth creating between them slots open radially toward the outside, the slots having mutually parallel opposing edges, and bridges of material each connecting two adjacent teeth at their base on the side of the airgap and defining the bottom of the slot between these teeth, and a radially exterior yoke attached to the ring, windings placed in a distributed manner in the slots, with, per slot, at least a winding of a first phase and a winding of a second phase different than the first phase, these winding portions being separated within the slot by at least two thicknesses of sheet-form insulation, one piece of sheet-form insulation at least partially surrounding each of the windings.

24. A stator comprising: a radially interior ring, comprising: teeth creating between them slots open radially toward the outside, and bridges of material each connecting two adjacent teeth at their base on the side of the airgap and defining the bottom of the slot between these teeth, and a radially exterior yoke attached to the ring, windings placed in a distributed manner in the slots, with, per slot, at least a winding of a first phase and a winding of a second phase different than the first phase, these winding portions being separated within the slot by at least two thicknesses of sheet-form insulation, one piece of sheet-form insulation at least partially surrounding each of the windings, the windings each comprising at least one electrical conductor of rectangular transverse section wound on edge.

25. A stator comprising: a radially interior ring, comprising: teeth creating between them slots open radially toward the outside, and bridges of material each connecting two adjacent teeth at their base on the side of the airgap and defining the bottom of the slot between these teeth, and a radially exterior yoke attached to the ring, windings placed in a distributed manner in the slots, with, per slot, at least a winding of a first phase and a winding of a second phase different than the first phase, these winding portions being separated within the slot by at least two thicknesses of sheet-form insulation, one piece of sheet-form insulation at least partially surrounding each of the windings over the entire height of the slots, the sheet-form insulation being of a height substantially equal to the height of the slots.

26. A stator comprising: a radially interior ring, comprising: teeth creating between them slots open radially toward the outside, and bridges of material each connecting two adjacent teeth at their base on the side of the airgap and defining the bottom of the slot between these teeth, and a radially exterior yoke attached to the ring, windings placed in a distributed manner in the slots, with, per slot, at least a winding of a first phase and a winding of a second phase different than the first phase, these winding portions being separated within the slot by at least two thicknesses of sheet-form insulation, one piece of sheet-form insulation at least partially surrounding each of the windings, the pieces of sheet-form insulation each comprising two opposing longitudinal edges extending substantially along the longitudinal axis of the associated winding portion, the winding portions being rectangular in transverse section and the two opposing longitudinal edges of each piece of sheet-form insulation extending over the one same face of the corresponding winding portion, the longitudinal edges of the corresponding piece of sheet-form insulation extending over a face of the winding portion that is oriented toward the opening of the slot or toward a portion of the winding with a different phase, associated with that same slot.

27. The method as claimed in claim 1, each winding portion being covered with two pieces of sheet-form insulation formed into a U and fixed top to tail over the corresponding winding portion.

Description

DETAILED DESCRIPTION

[0104] The invention may be better understood from reading the following detailed description of nonlimiting exemplary embodiments thereof, and from studying the attached drawing in which:

[0105] FIG. 1 is a schematic and partial perspective view of a stator according to the invention, the yoke being partially attached to the ring,

[0106] FIG. 2 is a schematic view in transverse section of the stator of FIG. 1,

[0107] FIG. 3 is a schematic perspective view of the ring of the stator with the windings,

[0108] FIG. 4 is a detail of a view in transverse section of FIG. 3,

[0109] FIG. 5 depicts a detail of FIG. 4,

[0110] FIGS. 6A to 6C depict variants of FIG. 4,

[0111] FIGS. 7 and 8 depict variants of the securing of the sheet of insulation to a winding portion, and

[0112] FIG. 9 illustrates a method for securing the insulation to the winding portion.

[0113] FIGS. 1 to 5 depict a stator 2 of a rotating electrical machine. The stator makes it possible to generate a rotary magnetic field driving the rotation of a rotor, in the context of a motor, and, in the case of an alternator, the rotation of the rotor induces an electromotive force in the stator windings.

[0114] The examples illustrated hereinbelow are schematic and are not necessarily depicted to scale.

[0115] Stator

[0116] The stator 2 comprises windings 22 which are placed in slots 21 formed between teeth 23 of a toothed ring 25. The slots 21 are closed on the side of the airgap by bridges of material 27 each joining together two consecutive teeth of the ring 25 and having a radial opening 28 toward the outside of the ring 25.

[0117] The stator 2 comprises a yoke 29 attached to the ring 25. The yoke 29 has recessed reliefs 50 of the mortise type collaborating with projecting reliefs of the dovetail type 52 belonging to the toothed ring 25, for mounting the yoke 29 on the ring 25.

[0118] The slots 21, in the example described, have mutually parallel radial edges 33 and, in section in a plane perpendicular to the axis of rotation X of the machine, are substantially rectangular in shape.

[0119] The bottoms of the slots 35 are of a shape substantially complementing that of the windings 22. In the example of FIGS. 1 to 4, the bottoms of the slots 35 have two planar portions 30 one on each side of the recess 40 and against which the rectangular windings 22 bear. The bottoms of the slots 35 are connected to the radial edges 33 by fillets 36.

[0120] The bridges of material 27 may be of constant thickness, as illustrated, and may be substantially nondeformable. In a variant which has not been illustrated, the bridges of material 27 each have a zone of reduced magnetic permeability, notably a localized restriction, a crushing of material, a localized treatment or one or more openings, allowing the lamination to become magnetically saturated, thereby limiting the passage of magnetic flux, and/or each have a deformable zone making it possible to vary the circumferential diameter of the ring 25.

[0121] The ring 25 and/or the yoke 29 are each formed of a pack of magnetic laminations which are stacked along the axis X, the laminations being, for example, identical and exactly superposed. They may be held together by clipping, by rivets, by tie rods, by welding and/or by any other technique. The magnetic laminations are preferably made of magnetic steel.

[0122] The ring 25 and/or the yoke 29 may alternatively be formed of one or more strip(s) of sheet metal cut out and wound on itself (themselves).

[0123] Windings and Insulation

[0124] The windings 22 may be placed in the slots 21 in a concentrated or distributed manner, preferably a distributed manner.

[0125] In the example illustrated in FIG. 2, the electrical conductors 34 of the windings 22 are placed in the slots in an arranged orderly manner.

[0126] As visible in FIG. 4, the electrical conductors 34 preferably have a rectangular flattened transverse section and are radially superposed, for example in a single row. They are superposed on one another via the flat. The windings 22 are said to be wound edge-on. The windings 22 may, in transverse section, be substantially rectangular in shape.

[0127] In the examples illustrated, the windings 22 have a single radial row of electrical conductors 34. However, the windings 22 may have a plurality of radial rows of electrical conductors, for example two rows of electrical conductors.

[0128] Each slot 21 is able to accept two stacked winding portions 22a and 22b, with different phases. Each winding 22 may, in transverse section, be substantially rectangular in shape.

[0129] In the example illustrated in FIG. 4, each slot 21 accepts two winding portions 22a and 22b with different phases.

[0130] Each winding portion 22a and 22b intended to be engaged in a slot 21 is surrounded with a sheet of insulation 37a and 37b able to insulate the windings from the walls 33 and 36 of the slot and to insulate from one another the winding portions 22a and 22b with different phases.

[0131] The windings 22 are formed outside of the slots 21 and their portions 22a and 22b that are intended to be engaged in the slots are each surrounded with a sheet of insulation 37a or 37b. The sheet of insulation 37a or 37b is coated with adhesive over at least part of its surface and the winding portions 22a and 22b with the sheets of insulation 37a and 37b on them are inserted into the slots 21. This operation is made easier by the fact that the slots 21 are fully open radially toward the outside.

[0132] Each sheet of insulation 37a or 37b extends over the entire height of the winding portion 24a or 24b inserted in the corresponding slot 21. As a preference, and as illustrated in FIG. 3, the sheets of insulation 37a or 37b may extend axially out of the slots 21 on each side of the ring 25.

[0133] The sheets of insulation 37a and 37b may have a layer of adhesive over their entire surface, so that they can be secured by adhesive bonding to the corresponding winding portion 24a and 24b. As an alternative, the sheets of insulation 37a and 37b are secured to the winding portions 22a and 22b by any other means.

[0134] The sheets of insulation 37a and 37b may be made of aramid, for example of Nomex®, or may be made of a laminate of aramid and of polyester or of polyimide, for example made of a Nomex® laminate of NMN (Nomex®-Mylar®-Nomex®) type or of NKN (Nomex®-Kapton®-Nomex®) type.

[0135] As has been illustrated in FIGS. 4 and 5, each sheet of insulation 37a or 37b may be wrapped twice around the corresponding winding portion 22a or 22b. The winding portion 22a or 22b is therefore insulated from the slot 21 by two thicknesses of the corresponding sheet of insulation 37a or 37b.

[0136] The longitudinal edges 54a or 54b of the sheets of insulation 37a or 37b extend over the same face 60a or 60b of the winding portion 24, particularly over a face 60a or 60b of the winding 22 corresponding to the flat of the electrical conductors 34. The winding portions 22a and 22b are oriented in the slots 21 in such a way that the faces 60a face the faces 60b. Thus, the winding portions 22a and 22b with different phases that are in the one same slot are separated from one another by two thicknesses of insulation 37a and by two thicknesses of insulation 37b, namely by four thicknesses of insulation.

[0137] As illustrated in FIG. 3, the windings 22 form winding overhangs 56 on the outside of the slots.

[0138] The winding overhangs 56 of adjacent windings 22 with different phases have connection portions 58 that are without any insulation.

[0139] Rotor

[0140] The rotor 1 depicted in FIG. 1 comprises a central opening 5 for mounting on a shaft and comprises a magnetic rotor mass 3 extending axially along the axis of rotation X of the rotor, this rotor mass being formed for example by a pack of magnetic laminations stacked along the axis X, the laminations being, for example, identical and exactly superposed.

[0141] The rotor 1 for example comprises a plurality of permanent magnets 7 placed in housings 8 of the magnetic rotor mass 3. As an alternative, the rotor is a wound rotor.

[0142] Method for Manufacturing the Stator and Machine

[0143] The stator may be obtained using the method of manufacture which will now be described.

[0144] The windings 22 are wound, notably on edge, by winding the electrical conductors 34. The windings 22 have rectilinear portions 22a and 22b which are intended to be inserted into the slots 21. These rectilinear portions 24 are surrounded with sheet-form insulation 37a or 37b, each sheet of insulation 37a or 37b being as described hereinabove. The sheets of insulation 37a or 37b are secured to the corresponding winding portion 22a or 22b by adhesive bonding or by some other means. The sheets of insulation 37a or 37b provide the windings with insulation from the pack of laminations and from each other.

[0145] The pieces of sheet-form insulation 37a and 37b may be secured to the winding portions 22a and 22b using the method illustrated in FIG. 9:

[0146] A. The sheet-form insulation 37a is first of all placed flat on a platform of a folding device, not depicted.

[0147] B. A first face 80a of the winding portion 22a that is to be insulated is set down on the insulation, applying a pressure P using a retaining tool on a second face 81 opposite to the first face 80,

[0148] C. The two free sides of the piece of sheet-form insulation 37a, which extend on either side of the winding portion 22a, are folded over and smoothed out simultaneously or otherwise onto the lateral faces 82 and 83 using flap-folding wings of the platform of the folding device,

[0149] D. The free flap of the piece of sheet-form insulation 37a extending from the face 82 is folded over onto the second face 81 using a slide sliding along the second face 81 starting from the face 82 or from a flap-folding wing of the platform of the folding device,

[0150] E. The free flap of the piece of sheet-form insulation 37a extending from the face 83 is folded over onto the portion of sheet-form insulation folded over in step D onto the second face 81. This step is performed using a slide sliding along the second face 81 starting from the face 83.

[0151] F. A pressure P is applied to the second face 81, using the retaining tool of the folding device.

[0152] In the method described hereinabove, the piece of sheet-form insulation 37a is coated with adhesive. In a variant, the winding portion 22a is coated with adhesive and a layer of adhesive is applied to the piece of sheet-form insulation superposed with the second face 81 between steps D and E in order to allow the securing of the portion of sheet-form insulation that is folded over in step E.

[0153] The invention is not restricted to this method of adhesive application or to the use of an adhesive-coating device, it being possible for the application of adhesive to be performed by hand.

[0154] Next, the rectilinear portions 22a and 22b of the windings 22 surrounded with the sheets of insulation 37a or 37b are inserted into the slots 21 of the ring 25 by a radial movement toward the inside of the slots 21. Two rectilinear winding portions 22 with different phases are inserted successively into the one same slot 21. The two rectilinear portions 22a and 22b of windings 22 belonging to a slot 21 are superposed radially and oriented in such a way that the faces 60 of the two windings are oriented toward one another.

[0155] In an additional step, the yoke 29 is attached to the ring 27 by sliding the dovetails 52 in the mortises 50. The yoke 29 may be heated beforehand in order to expand it and make it easier to insert over the ring 25. After it has been inserted over the ring 25, it may shrink as it cools, making it possible to achieve minimal clearance between the ring 25 and the yoke 29.

[0156] As a variant or in addition, the ring 25 may be cooled beforehand in order to shrink it and make the insertion of the yoke 29 easier.

[0157] The embodiments illustrated in FIGS. 6A and 6B differ from those of FIGS. 1 to 5 in terms of the way in which the sheets of insulation 37a and 37b are wrapped around the winding portions 22a and 22b.

[0158] In the embodiment illustrated in FIG. 6A, the sheets of insulation 37a and 37b are wrapped around the corresponding winding portion 22a or 22b over a little more than one turn. Each longitudinal edge 54a or 54b of the sheet of insulation 37a or 37b becomes superposed with a layer of the same sheet of insulation 37a or 37b and with a same face 60a or 60b of the windings. Thus, the winding portions 22a and 22b are insulated from the slot by a single thickness of insulation 37a or 37b and are insulated from one another by two thicknesses of insulation 37a and by two thicknesses of insulation 37b, namely by four thicknesses of insulation.

[0159] In the embodiment illustrated in FIG. 6B, the sheets of insulation 37a and 37b are wrapped in such a way that their longitudinal edges 54a and 54b face one another on the faces 60a and 60b without becoming superposed. The winding portions 22a and 22b of a slot 21 are placed in the slots 21 in such a way that the faces 60a and 60b with which the longitudinal edges 54a and 54b of the pieces of sheet-form insulation 37a and 37b become superposed are both oriented toward the opening 28. The winding portions 22a and 22b are insulated from the slot 21 by one thickness of the sheet of insulation 37a or 37b, and are insulated from one another by a discontinuous thickness of insulation 37b and a continuous thickness of insulation 37a. In this embodiment, the surface of the winding portion 22a or 22b may be coated with adhesive in place of or in addition to the adhesive-coating of the sheet-form insulation.

[0160] In the embodiment illustrated in FIG. 6C, each winding portion 22a and 22b is insulated from the outside by two pieces of sheet-form insulation 37a or 37b shaped into a U. The two pieces of sheet-form insulation 37a or 37b are placed around the corresponding winding portion 22a or 22b head to tail and overlap at least partially, notably overlapping on the faces 60a and 61a or 60b and 61b oriented toward the airgap and the opening of the slot 21. The winding portions 22a and 22b are insulated from the slot 21 by one thickness of the sheets of insulation 37a or 37b, and are insulated from one another by two thicknesses of insulation 37a and 37b, each of the thicknesses being formed by one of the pieces of sheet-form insulation 37a or 37b.

[0161] In the variant illustrated in FIG. 7, the sheet-form insulation 37a or 37b is not stuck to the surface of the corresponding winding portion 22a, but is attached using adhesive tape 62 at its two ends.

[0162] In the variant illustrated in FIG. 8, the sheet-form insulation 37a or 37b is an adhesive tape which is wrapped around the winding portion 22a. The consecutive turns of the tape partially overlap in order to provide good insulation. In this embodiment, the adhesive tape is preferably made of mica/polyester.

[0163] Of course, the invention is not limited to the exemplary embodiments that have just been described, and the rotor can be a wound rotor rather than a permanent-magnet rotor.

[0164] The expression “having a” should be understood to be synonymous with “comprising at least one”.