Coil head guide, associated wound rotor and method for winding an associated wound rotor

Abstract

The invention relates to a coil head guide (12). According to the invention, the coil head guide comprises at least one branch (30) having a front face (13) on which an electric wire for winding an electric machine can be wound, and at least one bearing boss (20) for the electric wire that is located at a distance from said branch and protrudes with respect to a mean plane of said front face, characterized in that said at least one bearing boss has recessed in it a groove for receiving said electric wire.

Description

Description Title of the invention: COIL HEAD GUIDE, ROTOR ASSOCIATED COIL AND METHOD FOR WINDING A ROTOR ASSOCIATED COIL Technical field

[0001] The present invention relates generally to electrical machines

[0002] It particularly concerns a reel head guide.

[0003] It also relates to a wound rotor including such a coil head guide and having an electric wire wound around the teeth to form windings. It also relates to a method of winding a wound rotor.

[0004] The invention finds a particularly advantageous application in the winding of wound rotors of electric motors, more particularly still of electric vehicle motors. Technological background

[0005] Hybrid or electric motor vehicles include at least one electric motor, powered by a current source such as a storage battery, and enabling the vehicle to be propelled.

[0006] These electric motors comprise a part that remains fixed relative to the chassis of the motor vehicle in question, called the stator, and a rotating part, called the rotor.

[0007] There are two main types of rotors: permanent magnet rotors and wound rotors. The latter may be preferred, particularly because they do not contain rare earth elements.

[0008] These wound rotors comprise a shaft and a plurality of teeth regularly distributed around this shaft and defining inter-pole notches between them. The teeth extend radially from the shaft, along its entire length.

[0009] Windings are formed by wrapping an electrically conductive wire around the teeth. The flow of an electric current within the wire leads to the generation of a magnetic field. This generates a torque, causing the wound rotor to rotate under the influence of an external magnetic field created by the stator.

[0010] Each of the teeth has two opposite ends on which are positioned support members to facilitate the winding of the electric wire around the teeth. The ends of the teeth receiving the windings of electric wire are otherwise called: "coil heads" and the support members are also called: "coil head guide". A coil guide generally has a shape in sun, with a central ring and branches extending radially from this central ring. These branches are designed to be positioned in line with the teeth (against the coil heads), in order to facilitate winding and protect the electric wire.

[0011] In practice, the winding of the electric wire is ensured by a winding needle which winds the electric wire successively around all the teeth.

[0012] The current supply to the winding is ensured by an excitation ring which is mounted on the shaft, on the outside of the coil head guide, and to which the two ends of the electric winding wire are connected.

[0013] This type of winding has several drawbacks. A notable difficulty with this type of winding lies in the space constraint for the passage of the winding needle between the excitation ring and the coil head guide. This step requires, during the winding phase, the positioning of the excitation ring at a distance from the coil head guide, and bringing it closer to this guide at the end of the winding manufacturing process. In addition to the complexity inherent in setting up such a process, this bringing closer creates a slackening of the winding wire due to the reduction in the distance between the coil head guide and the crimping points of the ends of the electric wire on the excitation ring.

[0014] Furthermore, during the winding of the electric wire, the forces exerted on the electric wire to tighten it are transmitted to the tooth and the coil head guide around which the electric wire is wound. This deformation causes a slackening of the electric wire, particularly of the part of the wire going from the excitation ring to the first of the coils.

[0015] In other words, once the winding is finished, the ends of the winding wire are not properly tensioned. This slackness results in a decrease in the reliability of the assembly when the winding wire is subjected to centrifugal force during rotor operation. A loose wire will in fact vibrate, which will cause it to gradually fatigue and, eventually, break. If the slackness of the wire is significant enough, it can also become inserted between the shaft and the excitation ring, which has the effect of very quickly damaging the wire during rotor operation. Summary of the invention

[0016] The invention aims to propose a solution to this problem. The proposed solution consists of placing a relief on the coil head guide such that, when the excitation ring is brought closer to the coil head guide, the electric wire engages on this relief and becomes taut.

[0017] The invention thus relates more specifically to a coil head guide comprising at least one branch having a front face on which a wire can be wound. electrical machine winding electric, and at least one support boss for the electric wire located at a distance from said branch and projecting relative to a mean plane of said front face, in which said at least one support boss has a hollow groove for receiving said electric wire.

[0018] This boss thus makes it possible to obtain a wound rotor whose wire connecting the excitation ring to the coil head guide is well tensioned, and which therefore resists well the forces exerted on it when it rotates at high speed. This boss also makes it possible to prevent the electric wire from being inserted between the shaft and the excitation ring.

[0019] Other advantageous and non-limiting characteristics of the coil head guide according to the invention, taken individually or in all technically possible combinations, are the following:

[0020] the receiving groove extends hollowly into a top of said support boss,

[0021] the support boss has a top and a lateral face, the top extending along a substantially flat surface except at the level of said receiving groove,

[0022] the coil head guide comprises a second support boss which has a hollow groove for receiving said electric wire,

[0023] the coil head guide has several branches distributed around an axis of rotation, and includes masses distributed around the axis of rotation of the coil head guide, so that the center of gravity of the coil head guide is located on the axis of rotation of the coil head guide,

[0024] the coil head guide comprises at least one stop which is located at a distance from the branch and protruding from the mean plane of said front face, and which has a lateral face configured to be in contact with the electric wire,

[0025] The spool head guide includes:

[0026] a central ring having an axis of rotation, and

[0027] several branches distributed regularly around the central ring and extending radially relative to said axis of rotation.

[0028] The invention also provides a wound rotor comprising:

[0029] an excitement ring,

[0030] a shaft one end of which is inserted into the excitation ring,

[0031] teeth distributed around the shaft and presenting two opposite faces,

[0032] a coil head guide according to one of the embodiments of the invention, each branch of which rests against one of the faces of one of the teeth,

[0033] at least one electric wire wound around at least one of said teeth and said branch to form a winding, and a part of which rests on the receiving groove of said at least one support boss of the coil head guide.

[0034] The invention also provides a method of winding a wound rotor comprising:

[0035] a step of positioning the excitation ring on the end of the shaft, at a distance from the coil head guide,

[0036] a winding step comprising:

[0037] a step of winding the electric wire around said tooth and said branch,

[0038] a step of passing the electric wire to an adjacent tooth to be wound, the winding and passing steps being repeated until all the teeth of the rotor are wound,

[0039] a rapprochement step during which the excitation ring is brought back into contact with the coil head guide by translation along the axis of rotation of the wound rotor,

[0040] in which, during the approaching step, the electric wire engages in a receiving groove of a support boss provided on the coil head guide projecting from a mean plane of said branch, thanks to the translation of the excitation ring.

[0041] Preferably, during the approach step, the electric wire comes to bear on the lateral face of a stop provided projecting from a mean plane of said branch, thanks to the translation of the excitation ring.

[0042] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations provided that they are not incompatible or mutually exclusive. Brief description of the figures

[0043] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0044] On the attached drawings:

[0045] [Fig.1] is a three-quarter schematic view of a wound rotor of an electric motor according to the invention.

[0046] [Fig.2] is a schematic longitudinal sectional view of the wound rotor of [Fig.1].

[0047] [Fig.3] is a three-quarter schematic view of the wound rotor coil head guide of [Fig.1].

[0048] [Fig.4] is a detail view of zone IV of [Fig.3], illustrating a support boss.

[0049] [Fig.5] is a schematic cross-sectional view of the support boss of [Fig.4],

[0050] [Fig.6] is a three-quarter schematic view of a coil head guide according to another embodiment of the invention. Device

[0051] A wound rotor 10 of a wound rotor motor is shown in [Fig.1 ]. This wound rotor motor is preferably intended to be installed in a motor vehicle. This can be any type of vehicle (car, truck, bus, boat, airplane, etc.). This is of a car, and the wound rotor motor is then designed to turn its wheels.

[0052] This wound rotor motor is of the radial flux type. It comprises a stator, not shown here, in the form of a ring. Unlike this stator which is fixed to the chassis of the vehicle, the wound rotor 10 is designed to rotate inside the stator, around an axis of rotation A2.

[0053] The wound rotor 10 here comprises an elongated shaft 42, which extends longitudinally along the axis of rotation A2 and which has a central portion - of constant radius - as well as two ends - of radii smaller than that of the central portion. One of the ends of the elongated shaft 42, called the front end, is inserted into an excitation ring 40. The reduction in section between the central portion and the front end of the elongated shaft 42 forms a shoulder 48 which extends in a plane orthogonal to the axis of rotation A2. The wound rotor 10 also comprises several teeth 44, here eight in number, which rise radially from the shaft 42 and which each extend over a portion of the length of the latter. These teeth are regularly distributed around the axis of rotation A2 and delimit between them spaces called inter-pole notches. It also comprises a set of eight coils 46 of electric wire 14 wound respectively around the teeth 44.

[0054] Preferably, each coil 46 is formed from the winding of the electric wire 14, forming a set of adjacent turns, around an axis which will be defined as the axis of the coil. This electric wire 14 comprises a core made of a conductive material, such as copper for example.

[0055] The 14 electric wire has a nominal diameter that can be between a few tens of micrometers and a few millimeters. This nominal diameter corresponds to the diameter of the wire core.

[0056] Indeed, the electric wire 14 is partially covered with a layer of enamel varnish, allowing for example to guarantee the electrical insulation between the turns of a coil, but also to protect the electric wire 14 from humidity, or from oxidation, while reinforcing its mechanical solidity.

[0057] The circulation of an electric current through the electric wire 14 generates a magnetic field in each of the windings 46 along their axes.

[0058] Thus, it is the circulation of an electric current which generates magnetic poles within the windings 46, allowing the rotation of the rotor around its axis of rotation A2 under the influence of the rotating magnetic field generated by the stator.

[0059] In the embodiment considered, all the windings 46 of the rotor 10 are wound with the same electric wire 14, by means of a machine comprising a winding needle provided for winding the electric wire 14 around the teeth.

[0060] As shown in [Fig.2], each tooth 44 has first and second opposite end faces 44a, 44b, which extend orthogonally to the axis of rotation A2, and which are each located on the side of one of the two ends of the shaft 42. Guide

[0061] A sun-shaped coil head guide 12 is placed in abutment against the first end faces 44b of the teeth 44. A second coil head guide, not described here, may be installed in abutment against the second end faces 44a of the teeth 44.

[0062] As shown in [Fig. 3], the coil head guide 12 comprises a central ring 34 centered on an axis of rotation A1 and branches 30, here eight in number, which extend radially from this central ring 34 and which are located in the extension of each tooth 44.

[0063] The central ring 34 is here engaged on the central part of the elongated shaft 42, close to the shoulder 48.

[0064] When the coil head guide is integrated into the wound rotor 10, the axis of rotation A1 of the coil head guide 12 merges with the axis of rotation A2 of the wound rotor 10.

[0065] Its branches 30 each have a rear flat face intended to be applied against the first face 44b of the corresponding tooth 44 and a front face facing away.

[0066] Each branch 30 is attached by one end to the central ring 34, and has an opposite free end which is bordered by a rim making it possible to retain the winding wound around the tooth and this branch 30.

[0067] Each branch further has two edges which are curved towards the rear flat face. This curvature makes it possible to wind the electric wire 14 around the tooth 44 and this branch 30 while preventing it from bending (in which case it would be brittle at this bend). Excitation ring

[0068] The main function of the excitation ring 40 is to provide electrical power to the wound rotor when the latter rotates.

[0069] As shown in [Fig.2], the excitation ring 40 comprises an elongated part which forms a sleeve adapted to slide along the shaft 42 and which is bordered, at its end facing the coil head guide 10, by a collar.

[0070] The elongated part carries two electrically conductive rings allowing its connection to a power supply.

[0071] As suggested in [Fig. 2], the excitation ring 40 is configured to be able to be moved away from the shaft 42 by a translational movement carried out along the axis of rotation A2 of the rotor. This characteristic is important because it allows sufficient space to be cleared between the coil head guide 12 and the excitation ring 40 to allow the passage of the winding needle when winding the electric wire 14 around the teeth 44 and the branches 30. Once the winding of all the windings 46 of the rotor 10 has been produced, the excitation ring is also configured to be able to be brought back into contact with the shoulder 48.

[0072] The excitation ring 40 comprises, here at its collar, two connection parts to which the two ends of the electric wire are connected. In practice, it comprises a first crimping point 60 on which the electric wire 14 is crimped before winding it around the teeth 44. Such a crimping point 60 is also called an input crimp. The part of the electric wire 14 connecting the input crimp 60 to the first winding 46 is called an input section. The excitation ring 40 also comprises a second crimping point, not shown here, on which the electric wire 14 is crimped at the output of the last winding 46 to have been wound. Such a crimping point is also called an output crimp. The part of the electric wire 14 connecting the output crimp to the last winding 46 is called an output section.

[0073] The excitation ring 40 also includes a pin 62 whose role is to prevent the input section from slipping between the excitation ring 40 and the shaft 42. Invention

[0074] According to a particularly advantageous characteristic of the invention, the coil head guide 12 comprises a support boss 20 for the electric wire 14, located at a distance from the nearest branch 30. In the embodiment considered, the nearest branch 30 is the branch 30 closest to the first winding 46.

[0075] According to the embodiment of the invention, the support boss 20 is located projecting from the front face of the central ring 34, on the passage of the input section. The support boss 20 is here shaped to increase for the electric wire 14 the length of the path to be traveled to connect the first winding 46 to the first crimping point 60 when the excitation ring 40 is bearing against the shoulder 48.

[0076] It is further designed so that when the excitation ring 40 is at a distance from the shoulder 48 (to allow the winding of the teeth), it is not in the path of the input section of the electric wire 14.

[0077] This support boss 20 is thus more precisely shaped so that the distance connecting the first winding 46 to the first crimping point 60 when the excitation ring 40 is at a distance from the shoulder (during winding) is strictly less than the distance that the electric wire must travel from the first winding 46 to the first crimping point 60 when the excitation ring 40 is bearing against the shoulder 48.

[0078] The presence of the support boss 20 therefore makes it possible to increase the tension applied to the electric wire 14 and consequently to re-tension the electric wire 14 between the first winding 46 and the first crimping point 60.

[0079] Furthermore, increasing the voltage applied to the electrical wire 14 makes it possible to limit the vibration movements of the electric wire 14, consequently limiting the forces exerted on it when the wound rotor 10 rotates at high speed. The boss 20 also makes it possible to prevent the electric wire 14 from passing under the pin 62 and becoming inserted between the excitation ring 40 and the shaft 42.

[0080] As shown in [Fig.4], the support boss 20 projects from a mean plane PI of the front face 13.

[0081] The mean plane is understood to be the plane which is orthogonal to the axis of rotation Al and which passes closest to the points on the front face of the branches, for example in the sense of the least squares method.

[0082] We could also define this average plane as the plane which is orthogonal to the axis of rotation Al and which corresponds to the plane along which the first turns of the electric wire rest against the branches.

[0083] As shown in [Fig.5], the support boss 20 has a top 20a and a lateral face 20b. The top 20a extends over a substantially flat surface 29 parallel to the mean plane PI, except at the level of the receiving groove 26. By substantially flat, it is meant that the latter is perfectly flat, or that it has reliefs of less than 1 mm and / or that the different parts of the surface 29 have relative inclinations of less than 10°. The lateral face 20b is here substantially cylindrical. By substantially cylindrical, it is meant that it is capable of performing functions which have their origin in a cylindrical shape.

[0084] Preferably, the dimensions of the receiving groove 26 are adapted to the dimensions of the electric wire 14 to ensure that the electric wire 14 is held within the receiving groove 26. Thus, the nominal diameter of the receiving groove 26 is equal to or slightly greater than that of the electric wire. It is 1.17 mm in the example considered here.

[0085] In order to avoid wear of the electric wire 14, the junction between the substantially flat surface 29 and the receiving groove 26 can be machined, for example to have a chamfer or a rounding.

[0086] In the embodiment considered, the receiving groove 26 extends longitudinally in a hollow in the top 20a of the support boss 20. The receiving groove 26 is profiled in a semi-cylindrical shape and is oriented so as to accommodate the electric wire 14.

[0087] As shown in [Fig. 3], the coil head guide 12 comprises a single support boss 20, for the entry section of the electric wire. But according to another embodiment of the invention not shown, the coil head guide could comprise a second support boss for the exit section of the electric wire. Preferably, this second support boss would have the same characteristics as the first support boss 20.

[0088] In order to avoid the creation of imbalances (lack of balance due to the weight of the support boss 20), additional masses can be distributed on the coil head guide so that the center of gravity of the coil head guide 12 belongs to the axis of rotation A1. These masses can for example be in the form of additional bosses projecting on the front face 13 in front of several other branches 30 (preferably in front of each branch).

[0089] These bosses 32 are not support bosses 20 within the meaning of the present invention and are not configured to be brought into contact with the electric wire 14. The number, shape, size, mass and distribution of the bosses 32 around the distribution axis A1 of the coil head guide 12 are configured so that the center of gravity of the coil head guide 12 belongs to the axis of rotation of the coil head guide 12. The shapes and number of these bosses will preferably be designed to avoid hindering the passage of the electric wire 14 in front of the coil head guide 12, such as for example for the input section or the output section.

[0090] In [Fig. 6], a first variant embodiment of the coil head guide is shown, which differs from that illustrated in [Fig. 1] in that it further comprises a stop 36 which is located on the central ring 34, at a distance from the branches 30, and which projects upwards relative to the mean plane PI of the front face 13. This stop 36 has a lateral face 36a configured to be in contact with the electric wire 14. In [Fig. 6], the stop 36 is shown on the side of the output section.

[0091] In this variant, the position of the stop 36 is chosen to be on the passage of the inlet section so that the latter is held against the lateral face 36a of the stop 36.

[0092] In addition, the coil head guide 12 could possibly comprise a second stop 36 positioned on the passage of the output section so that the latter is held against the lateral face 36a of the stop 36.

[0093] Advantageously, holding the electric wire 14 against the lateral face 36a makes it possible to limit the vibration movements of the electric wire 14, consequently limiting the forces exerted on it and the fatigue which results when the wound rotor 10 rotates at high speed.

[0094] In the embodiment considered, the angle between the lateral surface 36a and the mean plane PI has for example a value greater than or equal to 60° and less than or equal to 90°. Advantageously, the acute angle thus described between the mean plane PI and the lateral surface 36a creates an undercut preventing the electric wire 14 from rising along the lateral surface 36a, particularly during operation of the rotor, thus reinforcing the holding of the electric wire 14 against the lateral face 36a. Advantageously, the presence of the undercut also reinforces the holding of the electric wire within the receiving groove 26 of the support boss 20.

[0095] In the embodiment considered, the lateral surface 36a is planar along its height and non-planar along its length, so that it has a convex portion in contact with the electric wire 14. Alternatively, it could be concave along its height to have a receiving groove, not shown here, in which the electric wire 14 is inserted. Preferably, the dimensions of the receiving groove are adapted to the dimensions of the electric wire 14 to ensure that the electric wire 14 is held within the receiving groove. Thus, the nominal diameter of the receiving groove is 1.17 mm in the example.

[0096] Thus, the lateral surface 36a is adapted to the shape of the electric wire 14 at the outlet of the coil head guide 12. Advantageously, this reinforces the holding of the latter against the lateral surface 36a. Advantageously, the convexity of the lateral surface 36a also allows the electric wire 21 to avoid deterioration. Process

[0097] The invention also relates to a method of winding a wound rotor, for example the wound rotor 10 described above.

[0098] This process includes in summary:

[0099] a positioning step SI during which the excitation ring 40 is positioned on the end of the shaft 42, at a distance from the coil head guide 12,

[0100] a winding step S3 comprising:

[0101] a winding step S31 during which the electric wire 14 is wound around the tooth 44 and the branch 30,

[0102] a passing step S32 during which the electric wire 14 is passed towards the tooth to be wound 44. The winding steps S31 and passing steps S32 are repeated until all the teeth of the rotor 10 are wound,

[0103] a rapprochement step S6 during which the excitation ring 40 is brought back towards or into contact with the coil head guide 12 by translation along the axis of rotation A2 of the wound rotor 10.

[0104] According to a particularly advantageous characteristic of the invention, during the bringing together step S6, the electric wire 14 engages in the receiving groove 26 of the support boss 20 as a result of the translation of the excitation ring 40.

[0105] We can now describe these different stages in more detail.

[0106] During the positioning step SI, the excitation ring 40 is positioned on the end of the shaft 42, at a distance from the coil head guide 12 and the shoulder. This positioning can be obtained before mounting the excitation ring 40 on the shaft 42 or by moving the excitation ring 40 away from the shaft 42 by a translational movement carried out along the axis of rotation A2 of the rotor. At the end of this step, the first crimping point 60 is at a distance from the support boss 20. The electric wire 14 is therefore not engaged in the receiving groove 26 of the boss support 20.

[0107] During the winding step S31, the electric wire 14, crimped by one of its ends to the excitation ring 40 at the crimping point 60, is wound around the first tooth 44 and the branch 30 in contact with said tooth, turn after turn, over several thicknesses of turns.

[0108] The wire being applied taut, each turn tends to compress the tooth axially, which progressively relaxes the entry section of the electric wire 14.

[0109] During the passing step S32, the electric wire 14 is passed to another winding tooth 44. The winding tooth 44 may be a tooth adjacent to the one wound during the previous step or a tooth further away. During the passing step S32, the winding needle passes between the shaft 42 and the coil head guide 12 to bring the electric wire 14 to the winding tooth 44.

[0110] The winding steps S31 and passing steps S32 are repeated until all the teeth of the rotor 10 are wound.

[0111] The electric wire 14 at the output of the last tooth 44 having been wound is then crimped onto the excitation ring 40 on a second crimping point.

[0112] During the approach step S6, the excitation ring 40 is brought into contact with the coil head guide 12 by translation along the axis of rotation A2 of the wound rotor 10, which would again risk relaxing the input section of the electric wire 14.

[0113] But thanks to the invention, when the excitation ring 40 is brought into contact with the coil head guide 12 by translation along the axis of rotation A2 of the wound rotor 10, the electric wire 14 engages naturally and automatically in the receiving groove 26 of the support boss 20 (the groove being well positioned for this purpose). When the excitation ring 40 is in contact with the shoulder 48 of the elongated shaft 42 and the coil head guide 12, the crimping point 60 is located at the rear of the top of the support boss 20. Consequently, the distance traveled by the electric wire 14 to connect the first winding 46 and the first crimping point 60 is greater than the distance between the first winding 46 and the first crimping point 60.

[0114] Advantageously, the presence of the support boss 20 therefore makes it possible to increase the tension applied to the electric wire 14 and consequently to re-tension the electric wire 14 between the first winding 46 and the first crimping point 60.

[0115] In the variant where the coil head guide 12 comprises two support bosses 20, in the same way as for the input section, the output section of the electric wire 14 will come to rest in the receiving groove 26 of the second support boss 20 thanks to the movement carried out by the excitation ring 40, brought into contact with the coil head guide 12 by translation, which will make it possible to re-tension this output section.

[0116] In the variant illustrated in [Fig.6], during the approximation step S6, the input section comes to bear on the lateral face 36a of the first stop 36 due to the translation of the excitation ring 40. Holding the input section against the lateral face 36a then makes it possible to limit the vibration movements of the input section when the wound rotor 10 rotates at high speed, limiting the forces exerted on it and the resulting fatigue.

[0117] Of course, if the spool head guide has two stops, the two sections will come to bear against these two stops, which will limit the vibrations of these two sections. Variants

[0118] The present invention is in no way limited to the embodiment described and shown, but those skilled in the art will be able to provide any variation in accordance with the invention.

[0119] In the embodiment illustrated in [Fig.l], the coil head guide 12 is molded in one piece. But in a variant of the invention, the support boss could be attached to the coil head guide by gluing, molding or additive manufacturing.

[0120] In another variant of the invention, the bosses could be attached to the coil head guide by gluing, molding or additive manufacturing on the coil head guide.

[0121] In another variant of the invention, the receiving groove could extend across the top and the lateral face of the support boss and open in an inclined direction (for example at 45° relative to the mean plane of the branches of the coil head guide).

[0122] In another variant of the invention, the support boss could have a hemispherical shape.

[0123] In another variant of the invention, the top could be hemispherical in shape and the side face is cylindrical in shape.

[0124] In another variant of the invention, the masses of the branches could be designed to take into account the variation in the position of the center of gravity of the coil head guide due to the presence of at least one support boss, so that the center of gravity of the coil head guide is located on the axis of rotation of the coil head guide without having to resort to adding masses to the coil head guide.

[0125] In another variant of the invention, the coil head guide could comprise at least two stops, each projecting relative to the mean plane of the front face and part of the lateral faces of which are located opposite each other and separated by a distance equal to the diameter of the electric wire, so that the electric wire engages between the two lateral faces.

Claims

Claims

1. Coil head guide (12) comprising at least one branch (30) having a front face (13) on which an electric wire (14) for winding (46) an electric machine can be wound, and at least one support boss (20) for the electric wire (14) located at a distance from said branch (30) and projecting relative to a mean plane (PI) of said front face (13), characterized in that said at least one support boss (20) has a hollow groove (26) for receiving said electric wire (14).

2. A coil head guide (12) according to claim 1, wherein the receiving groove (26) extends hollowly into a top (20a) of said support boss (20).

3. A reel head guide (12) according to claim 1 or 2, wherein the support boss (20) has a top (20a) and a side face (20b), the top (20a) extends along a substantially flat surface (29) except at the level of said receiving groove (26).

4. Coil guide (12) according to one of claims 1 to 3, further comprising a second support boss (20) which has a recessed receiving groove (26) for said electric wire (14).

5. Coil head guide (12) according to one of claims 1 to 4, having several branches (30) distributed around an axis of rotation (Al), and further comprising masses (32) distributed around the axis of rotation (Al) so that the center of gravity of the coil head guide (12) is located on the axis of rotation (Al).

6. Coil head guide (12) according to one of claims 1 to 5, further comprising at least one stop (36) which is located at a distance from the branch (30) and protruding relative to the mean plane (PI) of said front face (13), and which has a lateral face (36a) configured to be in contact with the electric wire (14).

7. Coil head guide (12) according to one of claims 1 to 6, comprising: a central ring (34) having an axis of rotation (Al), and several branches (30) distributed regularly around the central ring (34) and extending radially relative to said axis of rotation (Al).

8. Wound rotor (10) of an electric machine, comprising: an excitation ring (40), a shaft (42) one of the ends of which is inserted into the excitation ring (40), teeth (44) distributed around the shaft (42) and having two opposite faces (44a, 44b), a coil head guide (12) according to one of claims 1 to 7, each branch (30) of which bears against one of the faces (44a, 44b) of one of the teeth (44), at least one electric wire (14) wound around at least one of said teeth (44) and the branch (30) which bears on said tooth (44) to form a winding (46), and a part of which bears on the receiving groove (26) of said at least one bearing boss (20) of the coil head guide (12).

9. Method for winding a wound rotor (10) comprising an excitation ring (40), a shaft (42) one of whose ends is inserted into the excitation ring (40), teeth (44) distributed around the shaft (42) and having two opposite faces (44a, 44b), a coil head guide (12) comprising at least one branch (30) in contact with one of the faces (44a, 44b) of one of the teeth (44), the method comprising: a step of positioning (S1) the excitation ring (40) on the end of the shaft (42), at a distance from the coil head guide (12), a winding step (S3) comprising: a step of winding (S31) the electric wire (14) around said tooth (44) and said branch (30), a step of passing (S32) the electric wire (14) towards an adjacent tooth to be wound (44), the winding (S31) and passing (S32) steps being repeated until all the teeth of the rotor (10) are wound,a bringing together step (S6) during which the excitation ring (40) is brought back into contact with the coil head guide (12) by translation along the axis of rotation of the wound rotor (10), characterized in that, during the bringing together step (S6), the electric wire (14) engages in a receiving groove (26) of a support boss (20) provided on the coil head guide (12) projecting from a mean plane of said branch (30), as a result of the translation of the excitation ring (40).,

10. Method for winding a wound rotor (10) according to claim 9, in which, during the bringing together step (S6), the electric wire (14) comes to bear on the lateral face (36a) of a stop (36) provided projecting from a mean plane of said branch (30), by means of the translation of the excitation ring (40).

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