FR3069390A1 - ROTATING ELECTRIC MACHINE COMPRISING A DEVICE FOR MAINTAINING THE END OF AN ELECTRIC WIRE PARTICIPATING IN WINDING - Google Patents

Abstract

A rotating electrical machine comprises a rotor and a stator, the stator comprising an annular body of revolution about an axis and an electrical insulator carried by said body, the annular body defining a plurality of radial teeth around which is wound at least one electrical wire ( 34) forming a winding. The insulator comprises on the same face (17A): - a retaining device (84) blocking two portions (74C, 74D) of the electric wire (34) forming the coil; and a device (52) for holding a first end (72) of the electric wire (34) forming the winding, comprising two walls (54A, 54B) arranged facing each other and projecting from said face (17A). of the annular body and between which is held the first end (72) of the electric wire.

Description

ROTATING ELECTRIC MACHINE COMPRISING A DEVICE FOR HOLDING THE END OF AN ELECTRIC WIRE PARTICIPATING IN THE WINDING

The present invention relates to a rotary electric machine comprising a wound stator and more particularly relates to devices fitted to such a rotary electric machine to ensure good tension of the electric wire participating in the winding.

The invention finds a particularly advantageous, but not exclusive, application in the field of rotary electrical machines forming an actuator for ensuring the rotational drive of motor vehicle fans.

Such fans installed on the front of the vehicle are intended to generate an air flow passing through a stack of heat exchangers, for example an engine cooler and an air conditioning condenser positioned one behind the other.

For this purpose, these fans include a propeller rotated by a bell-shaped rotor, positioned around a stator. The stator includes radial teeth spaced angularly about a central axis, each radial tooth serving to support a coil formed by winding an electric wire around several of these teeth. The coils thus formed are connected to an electronic control module via an interconnector, in order to supply said coils with different phases of current to allow synchronous operation of the rotating electric machine.

The stator is wound using a needle device for guiding the winding of an electric wire around a tooth, so as to form successive turns along said tooth. Before the winding step, one end of the electric wire must be held against the stator to allow the needle device to apply sufficient mechanical tension to form compact and contiguous turns around each tooth.

For this, a first technique consists in soldering the end of the electric wire on the interconnector. However, this solution has the drawback of lengthening the time for producing the stator because the initial welding operation to block the wire requires a certain time of production and cooling. According to another drawback, this solution requires steps of intermediate welding of the wire on electrical traces of the interconnector as and when the stator is wound. These intermediate welding operations do not make it possible to stiffen the entire winding since a stress is applied to the welding points to finalize the winding.

The invention aims to propose a rotary electric machine comprising a means for holding the end of an electric wire participating in the winding of the machine, simple and quick to use, while preserving the quantity of electric wire necessary for winding and the mechanical structure of the coil support.

For this, the invention presents a rotary electrical machine comprising a rotor and a stator, the stator comprising an annular body of revolution about an axis and an electrical insulator carried by said body, the annular body defining several radial teeth around which is wound at least one electric wire forming a coil.

The invention is characterized in that the insulator comprises, on the same face, a retaining device blocking two portions of the electric wire forming the winding and a device for holding a first end of the electric wire forming the winding, comprising two walls arranged opposite and projecting from said face and between which the first end of the electric wire is held.

In other words, the walls facing the holding device and the retaining device extend from the same face of the insulation, in order to provide support points for constraining and bending the wire electric during a stator winding operation. More specifically, the end of the electric wire is held between the walls of the holding device in order to bend a portion of the electric wire in the direction of the retaining device, by resting on a wall of the holding device, and in order to be able to exert a tension on this wire allowing a reliable installation and without play around the elements of the stator. Another portion of the electric wire is also bent in an opposite direction, by resting on the retainer, so as to form two curvatures in opposite directions, in order to oppose a displacement of the end of the electric wire when we shoot it. Thus, the invention provides a simple and quick means of holding, formed by the particular arrangement of a holding device and a retaining device on the same face of an insulator, for holding a wire. electric on this face in order to produce a winding of one or more coils around the radial teeth of said body. According to another advantage, the fact of being able to carry out the various welds of the wire on traces of the interconnector after the installation of the entire winding makes it possible to stiffen the winding by applying an additional means of holding the wire.

Preferably, the retaining device and the holding device are arranged on the same axial end face of the insulation, arranged perpendicular or substantially perpendicular to the axis of revolution of the annular body.

According to a characteristic of the invention, the holding device is adjacent to the retaining device. This advantageously makes it possible to reduce the portion of electric wire between said devices and to be able to tension the wire as efficiently as possible to allow the most taut winding possible.

The retaining device may comprise a connection tab, arranged in contact with a wall of the holding device, and a tongue which can be folded down on this connection tab along a folding axis to block said two portions of the electric wire. In other words, the retaining device can designate a device for crimping two portions of the electric wire between a tab folded down on a connection tab. The invention thus makes it possible to maintain the end of the electric wire on the insulation, and in particular on an axial end face of said insulation, without a welding step, which makes it possible to preserve the structure of the insulation and to reduce the time required to fix the electrical wire on said insulator.

According to another characteristic of the invention, the folding axis is substantially normal to a wall of the holding device, preferably to the wall adjacent to the retaining device. This embodiment advantageously makes it possible to form an angle of curvature of the electric wire which is substantially straight at the level of the first end of a zone for receiving the electric wire formed by the shape of the holding device.

According to another characteristic of embodiment of the invention, the folding axis is substantially normal to the direction of elongation of a radial tooth. In other words, the folding axis is substantially collinear to a radial direction of the annular body. This embodiment advantageously makes it possible to form an angle of curvature of the electric wire which is substantially straight or acute at the level of the folding tab in order to optimize the maintenance of the electric wire at the level of the holding means formed by the holding device and the holding device. detention.

According to other characteristics of the invention, the two walls of the holding device are oriented so as to approach each other, so as to form a reception area for the first end of the electric wire. For example, said walls approach towards the center of the stator And this receiving zone formed between the two walls of the holding device can extend from a passage formed at a first end of the walls to a wall reinforcement arranged between said two walls at their second end. In other words, the walls delimit a reception area on the surface of the stator, the width of which decreases as one approaches the center of the stator. By the term "width" is meant here a distance separating the faces of the walls which are opposite. This embodiment advantageously makes it possible to maintain in the reception area electric wires whose ends are of different diameters.

The holding device may include a slot arranged in the reinforcing wall, said slot forming a section restriction allowing the first end of the electric wire to be blocked. This offers the advantage of better retention of the end of an electric wire inserted in said slot.

The folding axis of the folding tab can pass at the first end of the receiving area, which optimizes the path of the electric wire between the holding device and the retaining device in order to save the length electric wire.

According to another characteristic of the invention, at least one wall of the retaining device has a lug on an outer face, configured to hold the connection tab of the retaining device against the face of the insulation. The external face is opposite to an internal face of the wall delimiting the reception zone. The presence of a lug on the outside of the holding device allows it to hold both the end of an electrical wire and the retaining device on the insulation. According to another advantage, the presence of the lug provides a means of rapid retention of the retaining device by a clipping system. Preferably, the retaining device is clipped between two retaining devices each comprising a lug on an external face, in order to ensure better retention of the retaining device.

The face of the insulation from which the retaining and retaining devices protrude may include an additional thickness situated in the radial extension of the retaining device, between the folding tongue and a radial tooth. The presence of an extra thickness behind the folding tab offers the advantage of being able to cut the electric wire as close as possible to the retaining device in order to optimize the length of electric wire necessary for winding one or more radial teeth. Preferably, the additional thickness is aligned with the connection tab of the retaining device.

Other alternative embodiments of the invention are possible, by combining the characteristics, variants and different embodiments of the invention mentioned above, according to various combinations not explicitly described, insofar as they are not incompatible or mutually exclusive.

The rotary electrical machine described above can in particular drive a propeller of a motor vehicle fan in rotation.

The invention also relates to a motor vehicle comprising a rotating electric machine described above.

The invention also relates to a method of winding an annular body of a rotary electric machine described above, implementing successively:

a first step of inserting one end of an electric wire between the walls of the holding device;

a second step of passing the electric wire through the first end of the holding device;

a third step of passing a portion of the electric wire between the connection tab and the foldable tongue of the retaining device, the foldable tongue being in a first unfolded position;

a fourth step of winding the electric wire around one or more radial teeth of the annular body;

a fifth step of passing another portion of the electric wire between the connection tab and the foldable tongue of the holding device, the foldable tongue being always in the first folded position;

a sixth step of folding the folding tab against the connection tab so as to press the two portions of the electric wire against the connection tab.

According to an alternative to the method described above, after the sixth folding step, the electric wire can be positioned on an extra thickness of the insulation, then cut on said extra thickness by a sharp object.

According to another alternative of the method described above, after the first insertion step, a first wedge can be housed between the walls of the holding device, so as to hold a portion of the electric wire against the bottom of the receiving area and / or a second wedge is disposed on a wall of the holding device, so as to limit the sliding of the electric wire along said wall.

According to another alternative of the method described above, after the fourth winding step the first wedge and / or the second wedge is removed from the holding device.

The invention will be better understood on reading the description which follows and on examining the schematic figures which accompany it, given by way of illustration, but in no way limitative of the invention, and among which:

Figure 1 is a perspective view from above of a rotary electrical machine according to the present invention;

Figure 2 is a perspective view from above of the stator body with radial teeth belonging to the rotary electric machine of Figure 1;

Figure 3 is a view of an interconnector adapted to be mounted on the cylinder head of Figure 2;

Figure 4 is a perspective view of a coupling trace configured to be mounted on the interconnector of Figure 3, the coupling trace here comprising three foldable tabs each in the raised or unfolded position;

Figure 5 is a perspective view similar to that of Figure 3 in which there is shown three traces of coupling in position on the interconnector, the foldable tabs being here illustrated each in the folded position;

Figure 6 is a detail view of the stator equipped with the interconnector and the coupling traces of Figure 5, making visible the cooperation of a retaining device and a holding device according to one aspect of the invention with an electric wire forming the stator winding;

Figure 7 is a detail view of Figure 6 from a different perspective angle;

Figures 8 and 9 are perspective views of the steps of a winding process of a radial tooth stator belonging to a rotary electric machine according to the present invention; and FIG. 10 is a perspective view of a rotor and a stator of a rotary electric machine equipped with a holding device and with a device for retaining an electric wire forming a coil according to one aspect of the 'invention.

Identical, similar or analogous elements keep the same reference from one figure to another.

Figure 1 shows an example of a rotating electrical machine 2. In this example, it is a brushless direct current rotating electrical machine, also called "Brushless direct curent" (BLDC).

The rotary electrical machine 2 comprises a rotor 4 in the shape of a bell on which is intended to be fixed a propeller (not shown). The rotor 4 carries on its internal periphery a plurality of permanent magnets 6 forming the poles of the rotary electric machine 2 (see also Figure 10). The rotor 4 is rotatably mounted on a shaft 8 shown here partially and which can be connected at its free end, opposite the rotary electrical machine, to a fan wheel.

The rotary electrical machine also comprises an electronic control module associated with a heat sink 10.

The rotor 4 surrounds a polyphase wound stator 12 so as to form an air gap between the internal periphery of the rotor 4 and the external periphery of the stator 12. More specifically, the rotor 4 has an annular wall 13 of axial orientation positioned around the stator 12 This annular wall is coaxial with the stator 12, of revolution around the axis X.

The stator 12 is shown in more detail in FIG. 2. The stator comprises an annular body 16 of revolution around the axis X and two insulators each disposed on each side axially of said body 16. The annular body 16 is delimited by two axial end faces 16A (only one of the faces being visible in the figures), delimiting axially with respect to the X axis the height of the annular body 16, each axial end face carrying one of the insulators. In particular, each insulator has a first axial end face disposed in contact with the associated axial end face of the body 16 and a second axial end face axially opposite to said first face. FIG. 3 shows in more detail one of the insulators which is the insulator 14, in particular disposed opposite the electronic control module and / or the heat sink 10. Thus, the insulator 14 has a second end face axial 17A extending opposite the electronic control module and / or the heat sink 10.

The annular body 16 is composed of a cylinder head 20 and radial teeth 18 distributed evenly at the outer periphery of the cylinder head. The radial teeth 18 delimit notches 22, such that each notch 22 is delimited by two successive radial teeth 18. The yoke 20 thus corresponds to the full internal annular portion of the annular body 16, which extends between the bottom of the notches 22 and the internal periphery of the stator 12. The notches 22 extend axially from one to the other of the axial end faces of the body 16. The notches 22 are also open radially towards the outside of the annular body 16. In the example illustrated, the stator 12 is provided with tooth feet 24 on the side of the free ends of the radial teeth 18 Each tooth base 24 extends circumferentially on either side of a corresponding radial tooth 18.

The stator 12 also comprises studs 26 coming from the internal periphery of the cylinder head 20 extending in radial projection towards the inside of the cylinder head 20. Each stud 26 projecting has an axial bore 28 passing through it which is configured to receive a member fixing not shown in the figures, to allow the fixing of the stator 12 on the heat sink 10 shown in Figure 1.

The stator 12 also comprises an interconnector 40, illustrated in FIG. 3, formed on the insulator 14. The interconnector 40 makes it possible to facilitate the winding of the electric wire around the radial teeth and to ensure the electrical coupling between this electric wire shown in Figures 6 to 10 and a connection terminal of the electronic control module integrated in the heat sink 10. For this, the interconnector 40 comprises a body 42 of revolution around the axis X, housed against the internal wall of the cylinder head 20 delimiting a central ring. The body 42 is made of an electrically insulating material such as a plastic material. The interconnector 40 also comprises circular grooves 43 arranged in the body 42 around the axis of revolution X of this body and of the stator when they are assembled, these circular grooves 43 being open at an end face axial 17A of the insulator 14. Each circular groove 43 is configured to receive a coupling trace 44 shown in FIG. 4.

A coupling trace 44 comprises an open ring 45 centered on the X axis, supporting a plurality of connection lugs 46, in number equal to the number of phases of the rotary electric machine 2. Each connection lug 46 is extended at its end free, that is to say its end opposite to the open ring, by a folding tab 48. Each coupling trace 44 has a plane of symmetry Pi passing through a connection tab 46B.

In Figure 4, the folding tabs 48A, 48B and 48C are shown in a first unfolded position. Each folding tongue 48 is configured to fold back into a second folded position, along a folding axis Z, on its associated connection tab 46A, 46B, 46C. In the folded position, the folding tab 48 thus forms a retaining device 84 capable of blocking one or more portions of electric wire against its specific connection tab 46. In other words, according to the present example, the retaining device 84 can allow the crimping of an electric wire. The coupling trace 44 is also provided with a connection terminal 47 extending one of the connection legs 46 and intended to be connected with a corresponding connection terminal of the electronic control module, integrated in the heat sink 10 shown in the figure. 1.

As shown in FIG. 5, each coupling trace 44 is inserted into a circular groove 43 of the body 42 so that their connection terminal 47 can be electrically connected to the electronic module. In the present case, it is thus possible to connect the stator via the three-phase coupling traces. This module includes switches, such as MOS type transistors for example, controlled to inject current into the different phases of the electric machine operating in motor mode.

To maintain the traces of coupling in the interconnector 40, the connection tabs 46 are held against the axial end face 17A of the insulation 14, by means of a plurality of walls 54 extending in projection from face 17A. In other words, two neighboring walls 54 participate in defining a housing accommodating a connection tab 46. The walls 54 thus prevent the pivoting of the coupling tracks 44 in the grooves 43. In addition, each wall 54 comprises a lug 60 (in particular visible on Figure 6) on an inner face 58, that is to say a face facing the housing for connection lug which it participates in defining, this lug 60 being configured to allow snap-fastening of the connection lug 46 against insulation 14.

Among the plurality of walls forming housings for the connection lugs of the coupling tracks 44, a wall 54A is defined which contributes to delimiting a first housing for a connection lug 46A and an adjacent wall 54B, participating in delimiting a second housing for a connection tab 46B, which are connected by a reinforcing wall 55 The internal faces 62 of the walls 54A and 54B delimit, with the axial end face 17A, a receiving zone 64 for an electric wire as shown in FIGS. 6 and 7. The height, in an axial direction, of the walls 54A and 54B is between a few millimeters and several millimeters, preferably of the order of 2 to 3 times the diameter of wire with enamel. The width of the reception area 64 decreases between a first end 66 and a second end 68 of the walls participating in delimiting this reception area, the first end 66 being turned towards the periphery of the rotating electric machine and the second end 68 towards the inside of it.

The reception area 64 is open at the first end 66 of the walls, in the direction of the radial teeth 18. It also has an opening at the second end 68 of the walls, by the presence of a slot 70 made in the reinforcing wall 55- Advantageously, the slot 70 is dimensioned to allow the maintenance of a first end 72 of an electric wire. The slot 70 is produced in the reinforcement wall 55 parallel to the axis of revolution, and chamfers 71 are formed on the top of the reinforcement wall on either side of the axis of the slot, in order to guide the electric wire when it is inserted into this slot 70. The width of the slot 70, in a circumferential direction, is between a few millimeters and several tens of millimeters, preferably it is of the order of 0.8 to 0, 9 times the diameter of the wire with enamel. According to one example, the width of the slot can vary as a function of the height of the reinforcing wall, in particular by decreasing towards the base of the reinforcing wall. This makes it possible to block wires of different diameters and thus to have a generic part which may be suitable for several stators whose diameter of winding wire is different.

The walls 54A, 54B, 55 and the slot 70 thus form a holding device 52 making it possible to hold on the axial end face 17A a first end 72 of an electric wire in said slot.

The rotary electrical machine thus comprises a holding device 52 for one end of the electric wire, disposed in the vicinity of one of the retaining devices 84. The holding device has a wall which participates in forming the housing of the connection tab of this restraint.

it should be noted that the folding axis Z of the folding tongue 48A is normal or substantially normal to the wall 54A, common to the holding device and to the delimitation of the housing of the retaining device, and that this folding axis passes close from the first end 66 of the receiving area 64. For example, the folding tab 48A is disposed adjacent, in a substantially circumferential direction, to the first end 66 of the receiving area 64. In this case, the folding axis Z of said tongue 48A is disposed at the same radial distance from the axis X as said end 66.

The insulator 14 also includes an extra thickness of material 76 on the axial end face 17A, between the folding tongue 48 of the retaining device 84 and the corresponding radial tooth 18 present in the radial extension. The advantages associated with these characteristics will be better understood on reading the following, namely the description of a process for winding the stator 12 using the holding device 52.

FIGS. 8 and 9 show the steps enabling a winding to be carried out using a holding device 52 and a retaining device 84 described above.

According to a first step, a first end 72 of an electric wire 34 is inserted between the walls 54 of the holding device 52 using a needle device 78. More specifically, the first end 72 of the electric wire 34 is forcibly inserted into the slot 70. A first wedge 80 can then be fitted into the slot 70 so as to firmly hold the end 72 against the bottom of the reception area 64, in particular to ensure that the electric wire does not debate not in the slot due to a sizing gap in the slot.

According to a second step, the electric wire is deployed through the reception area 64 to its first end 66. The needle device 78 then curves a portion 74A of the electric wire 34, by resting on the end of a walls of the holding device, and more particularly the wall 54A adjacent to the retaining device, so as to substantially align said electrical wire 34 with the axis Z of folding of the folding tongue 48A. A second wedge 82 can be forcibly fitted or disposed against the wall 54A, at the level of the first end 66, in order to limit the axial displacement along the wall 54A of the portion 74A of the electric wire, as illustrated in FIGS. 8 and 9.

According to a third step, the needle device 78 runs the wire along the internal face of the folding tongue 48A, in its original unfolded position shown in FIG. 4, then guides the electric wire to an opposite edge of the folding tongue 48, so that it can be bent in another direction at a portion 74B, by resting on said tongue.

According to a fourth step, in a known manner the needle device winds the electric wire 34 around each radial tooth 18 so as to form coils 32. As illustrated in FIG. 10, the coil 21 is formed by a plurality of coils 32 respectively wound around each radial tooth 18. The stator 12 thus comprises eighteen coils 32, surrounded by the rotor 4 comprising twelve permanent magnets 6 alternately polarized. According to the present example, the winding 21 is a three-phase winding formed from three sets of coils 32 coupled in a triangle through the interconnectors. The coils are thus formed by the same continuous electric wire 34. The diameter of the electric wire is here less than 1.5mm, and by way of example, this electric wire 34 can have a diameter of the order of 1.2mm. The electric wire 34 is preferably covered with a layer of electrically insulating material such as enamel.

According to a fifth step, after the winding of the last radial tooth 18, the needle device 78 again guides the electric wire 34 against the internal face of the folding tongue 48A, at its bending axis Z.

According to a sixth step, the folding tongue 48A forming a first part of the retaining device 84 is then folded against the corresponding connection tab 46A and forming a second part of the retaining device, so as to enclose and crimp two portions 74C and 74D of electric wire as illustrated in FIG. 7. The needle device 78 then positions the electric wire 34 at the level of the extra thickness 76 situated behind the folding tongue 48A, in order to allow a cutting tool to cut the electric wire 34 while resting on said excess thickness. Finally, the first and second shims are removed from the holding device 52, it being understood that these shims could be removed after the stator has been wound and before the portions of wire are crimped into the retaining device.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention from which one would not depart by replacing the various elements with any other equivalent. Furthermore, the various features, variants, and / or embodiments of the present invention can be combined with one another in various combinations, insofar as they are not incompatible or mutually exclusive of one another.

Claims (15)

1. Rotating electric machine (2) comprising a rotor (4) and a stator (12), the stator comprising an annular body (16) of revolution about an axis (X) and an electrical insulator (14) carried by said body, the annular body (16) defining several radial teeth (18) around which is wound at least one electric wire (34) forming a coil, characterized in that the insulator (14) comprises on the same face (17A): a retainer (84) blocking two portions (74C, 74D) of the electric wire (34) forming the coil; and a device (52) for holding a first end (72) of the electric wire (34) forming the winding, comprising two walls (54, 54A, 54B) arranged in opposite relation to said face (17A ) and between which is maintained the first end (72) of the electric wire. 2. Rotating electric machine (2) according to the preceding claim, characterized in that the holding device (52) is adjacent to the retaining device (84). 3. Rotating electric machine (2) according to one of the preceding claims, characterized in that the retaining device (84) comprises a connection tab (46, 46A), arranged in contact with a wall (54, 54A) of the holding device (52) and a folding tab (48, 48A) on this connection tab along a folding axis (Z), to block said two portions (74C, 74D) of the electric wire (34). 4. Rotating electric machine (2) according to the preceding claim, characterized in that the folding axis (Z) is substantially normal to a wall (54, 54A) of the holding device (52). 5. Rotating electric machine (2) according to claim 3 or 4, characterized in that the folding axis (Z) is substantially normal to the direction of elongation of a radial tooth 08). 6. rotary electrical machine (2) according to one of the preceding claims, characterized in that the two walls (54, 54A, 54B) of the holding device (52) are oriented so as to approach one of the other so as to form a receiving zone (64) of the first end (72) of the electric wire. 7. Rotating electric machine (2) according to claim 6, characterized in that the two walls (54, 54A, 54B) come closer towards the center of the stator (12). 8. rotary electrical machine (2) according to claim 6 or 7, characterized in that the receiving zone (64) formed between the two walls (54> 54A, 54B) of the holding device (52) extends from a passage formed at a first end (66) of the walls to a reinforcing wall (55) arranged between said two walls (54) at their second end (68). 9- Rotating electric machine (2) according to the preceding claim, characterized in that the holding device (52) comprises a slot (70) arranged in the reinforcement wall (55), said slot forming a section restriction allowing blocking of the first end (72) of the electric wire. 10. Rotating electric machine (2) according to one of claims 3 to 9, characterized in that at least one wall (54, 54A) of the holding device (52) has a lug (60) on an outer face ( 58), configured to hold the connection tab (46, 46A) of the retaining device (84) against the face (17A) of the insulation (14). 11. Rotating electric machine (2) according to one of claims 3 to 10, characterized in that the face (17A) comprises an extra thickness (76) located in the radial extension of the retaining device (84), between the foldable tongue (48, 48A) and a radial tooth (18). 12. A method of winding an annular body (16) of a rotary electrical machine (2) according to one of claims 3 to 11, implementing successively: a first step of inserting an end (72) of an electric wire (34) between the walls (54A, 54B) of the holding device (52); a second step of passing the electric wire (34) through the first end (66) of the holding device (52); a third step of passing a portion (74C) of the electric wire (34) between the connection tab (46A) and the folding tongue (48A) of the retaining device (84), the folding tongue being in a first position unfolded; a fourth step of winding the electric wire (34) around one or more radial teeth (18) of the annular body (16); a fifth step of passing another portion (74D) of the electric wire (34) between the connection tab (46A) and the folding tongue (48A) of the holding device (52), the folding tongue still being in said first unfolded position; a sixth step of folding the folding tab (48A) against the connection tab (46A) so as to press the two portions (74C, 74D) of the electric wire (34) against the connection tab (46A). 13- A winding method according to the preceding claim, characterized in that after the sixth folding step, the electric wire (34) is positioned on an extra thickness (76) of the insulation, then sectioned on said extra thickness by a sharp object . 14. Winding method according to one of claims 12 or 13, characterized in that after the first insertion step, a first shim (80) is housed between the walls (54A, 54B) of the holding device (52 ), so as to hold a portion of the electric wire against the bottom of the reception area (64) and / or a second wedge (82) is arranged on a wall (54A) of the holding device (52), so as to limit the sliding of the electric wire (34) along said wall (54) · 15 · Winding method according to the preceding claim, characterized in that after the fourth winding step the first wedge (8θ) and / or the second wedge (82) is removed from the holding device (52).