Wire retaining wedge in an inter-pole slot of a wound rotor, associated wound rotor, and method for winding an associated wound rotor

Abstract

The invention relates to a retaining wedge (30) for an electrical wire in an inter-pole slot. According to the invention, the retaining wedge comprises a body (32) which has a bearing apex (34) for said wire, said apex defining a receiving groove (36) for said wire. Figure for the abbreviation: Fig. 4.

Description

Title of the invention: Wire retaining wedge in an inter-pole slot of a wound rotor, associated wound rotor, and method for winding an associated wound rotor Technical field of the invention

[0001] The present invention relates generally to a winding method for a wound rotor, in which the electric wire passes at the bottom of the inter-pole slot.

[0002] It relates more particularly to a retaining wedge for an electrical wire in an inter-pole notch of a wound rotor.

[0003] The invention finds a particularly advantageous application in the winding of wound rotors of electric motors, more particularly of electric vehicle motors.

[0004] It also relates to a wound rotor including such a wedge and having an electrical wire wound around the teeth to form windings and part of which passes through one of the inter-pole notches. State of the art

[0005] Hybrid or electric motor vehicles include at least one electric motor, powered by a current source, and enabling the propulsion of the vehicle.

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

[0007] Known rotors comprise a longitudinal body and a plurality of teeth regularly distributed around this body and defining interpole notches between them. The teeth extend radially from the longitudinal body, along its entire length.

[0008] More specifically, some electric motors use a rotor with coils, called a wound rotor. These coils are formed by winding 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 field generates a torque, causing the wound rotor to rotate under the influence of an external magnetic field created by the stator.

[0009] Each tooth has two opposite ends on which support members are positioned to facilitate the winding of the electrical wire around the teeth. The ends of the teeth receiving the windings of electrical wire are also called: "coil heads" and the support members are also called: "coil head guides".

[0010] In order to wind the electrical wire around each tooth in one continuous piece, To allow each winding to be electrically powered by the same current source, known rotors feature inter-pole windings characterized by the passage of the electrical wire from one tooth to the next, in front of the rotor's coil head guide. The winding's current supply is provided by a rotating commutator located on the longitudinal body and connected to the first and last coils.

[0011] This type of winding presents several challenges. A significant difficulty lies in the space constraint for the passage of the winding needle between the rotating commutator and the coil head guide. This step necessitates moving the rotating commutator away from the coil head guide during the winding phase and bringing it closer at the end of the winding manufacturing process. Besides the inherent complexity of implementing such a method, this movement closer creates a slack in the coil wire, resulting in a decrease in the reliability of the assembly subjected to centrifugal force during rotor operation. Furthermore, the impregnation of the electrical wire at the face of the coil head guide cannot be achieved using this method.

[0012] A known winding method involves inter-pole winding by passing the electrical wire through the bottom of the inter-pole slot, rather than in front of the rotor's coil head guides. The wire passes diagonally through the inter-pole space (from one end of a tooth to the opposite end of the adjacent tooth). However, the portion of the electrical wire passing through the bottom of the slot is quite long and therefore slacker than within the coils. Consequently, the electrical wire is at risk of damage, particularly at the inter-pole passage, when the rotor is rotated under centrifugal force.

[0013] A known solution to this problem consists of encapsulation—also called resin encapsulation or "potting" according to the commonly used Anglo-Saxon term—of the coils and the portions of the wire passing through the inter-pole spaces. However, this solution has the disadvantage of considerably increasing the weight of the device, consequently reducing its reliability. Indeed, in the event of failure or damage to the resin used to encapsulate the device, the risk of detachment or fracture increases with the added mass, as the centrifugal force applied to the resin is proportional to its mass. Presentation of the invention

[0014] The invention aims to provide a solution to this problem and to allow winding at the bottom of the inter-pole slot without resorting to an encapsulation process. The proposed solution consists of the axial insertion of shims at the bottom of the slot to, in particular, hold the winding wires in a fixed position, this in order to to limit their movements during the operation of the rotor inside a stator but also to tighten the wire present at the bottom of the inter-pole slot.

[0015] The invention thus relates more specifically to a retaining wedge comprising a body which has a support apex for said wire, this apex delimiting a receiving groove for said wire.

[0016] The insertion of shims represents a comparatively smaller increase in mass than that resulting from encapsulation and limits the need for resin to hold the device in place. Thanks to the use of shims, the resin requirement is limited to simply impregnating the electrical wire. These shims thus make it possible to obtain a wound rotor in which the wire is well held, and which therefore withstands the stresses exerted on it when it rotates at high speed.

[0017] Other advantageous and non-limiting features of the wedge according to the invention, taken individually or in all technically possible combinations, are as follows: - the support apex comprises two substantially flat surfaces offset and joined by an inclined surface presenting a non-zero angle with the substantially flat surfaces in order to delimit with one of them said receiving groove, - the support apex has a plane of symmetry such that the receiving groove is separated into two symmetrical parts, - the support vertex has a plane of sagittal symmetry, the inclined surface and the receiving groove are separated respectively into two inclined surfaces and two receiving grooves by an edge belonging to the plane of sagittal symmetry, - the inclined surface extends in width between the two substantially flat surfaces and in length along an orthogonal direction, the surface being curved along its length so that it presents a convex portion adapted to come into contact with the electric wire, - the angle between the inclined surface and the flat surface has a value greater than or equal to 60° and less than or equal to 90°, - the body comprises a profiled base (32a) with a trapezoidal cross-section and a head which has two parallel lateral faces and which carries the apex, - the wedge comprises at least two distinct parts, each supporting a portion of the apex, - the wedge has a length between 10% and 150% of the length of a pole of the wound rotor, - a chamfer is present at the junction between one or the other of the substantially flat surfaces and the inclined surface.

[0018] The invention also proposes a wound rotor comprising: - a longitudinal body, - teeth distributed around the longitudinal body and defining inter-pole notches between them, - an electrical wire wound around the teeth to form coils, part of which passes through one of the inter-pole notches, - at least one wedge according to one of the embodiments of the invention, said part of the electric wire resting on the receiving groove of the wedge.

[0019] The invention also proposes a method for winding a wound rotor according to one of the embodiments of the invention, comprising, for at least two teeth: - a winding step comprising: • a step of winding the electrical wire around a first tooth, • a step of passing the electrical wire through the bottom of the inter-pole notch towards a adjacent tooth to be wound, and • a step of winding the electrical wire around the tooth adjacent to the one to be wound, - a step of setting up at least one retaining wedge in the inter-pole notch, in contact with said first tooth and the adjacent tooth.

[0020] Of course, the various features, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Detailed description of the invention

[0021] The following description with regard to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be carried out.

[0022] On the attached drawings:

[0023] [Fig-1] is a schematic ¾ view of a rotor of a wound-rotor electric motor according to the invention;

[0024] [Fig.2] is a schematic planar developed view of two adjacent coils seen along the axis of rotation Al of the rotor of the [Fig.l];

[0025] [Fig.3] is a schematic top view of a passage of the electric wire at the bottom of the inter-pole slot of the rotor of the [Fig.1];

[0026] [Fig.4] is a schematic ¾ view of a rotor wedge of the [Fig.1];

[0027] [Fig.5] is a schematic top view of a wedge according to another method of shearing rotor modification according to the invention;

[0028] [Fig.6] is a schematic ¾ view of a wedge according to another embodiment of the rotor according to the invention;

[0029] [Fig.7] is a summary diagram of a method for winding the rotor of the [Fig. 1] according to an embodiment of the invention.

[0030] A wound-rotor motor rotor is shown in [Fig. 1]. This motor is preferably intended for installation in a motor vehicle to rotate its wheels. It includes a stator, not shown here. Unlike this stator, which is fixed to the vehicle chassis, the rotor 10 is designed to rotate inside the rotor, around an axis of rotation A1.

[0031] The rotor 10 here comprises a longitudinal body 20 elongated along the axis of rotation Al and having two ends 22, 23. The rotor 10 also has several teeth 14, here eight in number, which rise radially from the longitudinal body 20 and each extend along its entire length. These teeth are regularly distributed around the axis of rotation Al and delimit between them spaces called inter-pole notches 16. It also comprises a set of eight coils 12 of electrical wire 24 wound respectively around the teeth 14. A star-shaped coil head guide 18, 19 is positioned against each end of the longitudinal body 20. This guide has arms located in line with each tooth, which have curved shapes to prevent the electrical wire 24 from being damaged.

[0032] As shown in [Fig. 2], each coil 12 is formed from the trapezoidal and helical winding of the electrical wire 24, forming a set of adjacent turns around an axis which will be defined as the axis of the coil. This electrical wire 24 has a core made of a conductive material, such as copper.

[0033] A trapezoidal winding is an ordered winding of the electrical wire 24 around the tooth 14, with the number of turns per layer decreasing from the top of the coil to the bottom of the coil 12. The bottom of the coil 12 corresponds to the side of the coil with the layer closest to the axis of rotation Al of the rotor and the bottom of the inter-pole slot 16. In an ordered winding, the wire runs across two adjacent turns of the lower layer to minimize gaps. In the embodiment considered, the lowest layer within the coil has one or two turns, as shown in [Fig. 2].

[0034] The inter-pole notch 16 is then delimited on each side by two coils 12 and at the bottom by the elongated body 20 (which forms the bottom of the notch). This inter-pole notch 16 is therefore profiled parallel to the axis of rotation AL. Its orthogonal section (with respect to this axis of rotation Al) has a base curved around the axis of rotation Al, and two sides delimited by the winding of the turns of the coils adjacent to the inter-pole notch 16.

[0035] The electrical wire 24 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's core.

[0036] Indeed, the electrical wire 24 is partially covered with a layer of enamel varnish, allowing, for example, the electrical insulation between the turns of a coil, but also protecting the electrical wire 24 from moisture or oxidation, while reinforcing its mechanical strength.

[0037] The thickness of the varnish layer indicates the grade of the electrical wire 24.

[0038] In the embodiment considered, the electrical wire 24 is grade 2. Thus, The thickness of the enamel varnish layer is between 0.07 mm and 0.10 mm. Here, it is assumed that the thickness of the enamel varnish layer is fixed at 0.075 mm.

[0039] It is also assumed here that the electrical wire 24 has an outside diameter (including the enamel coating) of 1.245 mm. Thus, the nominal diameter of the electrical wire 24 is 1.17 mm in the example.

[0040] The flow of an electric current through the electric wire 24 generates a magnetic field in each of the coils 12 along their axes.

[0041] Thus, it is the circulation of an electric current which generates magnetic poles within the coils 12, allowing the rotation of the rotor around its axis of rotation Al under the influence of the rotating magnetic field generated by the stator.

[0042] In the embodiment considered, all the coils 12 of the rotor 10 are wound with the same electrical wire 24, by means of a machine comprising a winding needle provided for winding the electrical wire 24 around the teeth.

[0043] As shown in [Fig.3], the passage of the electric wire 24 between at least two adjacent teeth 14 is made at the bottom of the notch 16 and connects the lowest layers of each coil 12.

[0044] Advantageously, the passage of the electrical wire 24 at the bottom of the notch facilitates the passage of the winding needle towards an adjacent tooth to be wound, since it does not require the winding needle to pass between the rotating collector of the elongated body 20 and the coil head guide.

[0045] It will be noted that the electric wire 24 can possibly pass from one to the other of two non-adjacent poles, this time in front of the coil head guide of the rotor 10, in which case it will once again connect the lowest layers of each coil 12.

[0046] The retention of the electrical wire 24 in the bottom of the inter-pole notch 16 is ensured by a retaining wedge 30 of the electrical wire 24. This wedge is intended to be inserted axially in the bottom of the inter-pole notch 16, that is to say according to a translational movement parallel to the axis of rotation AL Such a retaining wedge 30 of the electrical wire 24 is represented on [Fig.4] before its insertion in the bottom of the inter-pole notch.

[0047] It has been observed that bosses, i.e., irregularities in the winding around the tooth 14, form bulges at which the electrical wire 24 moves away from The surface of tooth 14 could appear at the coil head guides (i.e., where the electrical wire 24 is most curved). Advantageously, inserting the retaining wedge 30 into the bottom of the inter-pole notch 16 allows the coil 12 to be held more effectively against the tooth 14 of the rotor 10 at the coil head guides and reduces the bulging phenomenon.

[0048] The retaining wedge 30 is for example made of polymer-based plastic material.

[0049] The retaining wedge 30 has, for example, a length between 50% and 100% of the length of a tooth of the wound rotor.

[0050] The retaining wedge 30 has, for example, a width (measured ortho-radially with respect to the axis of rotation Al) varying radially such that the retaining wedge 30 has an identical shape, in negative, to that of the inter-pole notch 16.

[0051] In the embodiment considered, the retaining wedge 30 comprises a body 32 including a profiled base 32a of trapezoidal cross-section and, on the side of the top of this base, a head 32b of rectangular cross-section and of width equal to that of the head of the profiled base 32a.

[0052] The head 32b is designed to be oriented towards the elongated body 20, supported against the latter by its apex (hereinafter referred to as the support apex 34), while the profiled base 32a is oriented towards the outside of the rotor.

[0053] The shape of the base 32a is configured to facilitate the insertion of the body 32 into the bottom of the notch 16 and to ensure its retention there.

[0054] Once inserted into the bottom of the notch 16, the retaining wedge 30 is fixed to the rotor 10. The fixing is ensured for example by screwing and / or gluing, or simply by a press fit.

[0055] The support apex 34 delimits a receiving groove 36 for the electric wire 24, as shown in [Fig.4].

[0056] In the embodiment considered, the support apex 34 more precisely comprises two substantially flat surfaces PI, P2 and here substantially parallel, radially offset and joined by an inclined surface P3 extending in width between the two flat surfaces and presenting a non-zero angle with the substantially flat surfaces PI, P2 in order to delimit with one of them this receiving groove 36. By substantially flat and parallel, it is understood that these surfaces are perfectly flat and parallel, or that they have reliefs of less than 1 mm and / or relative inclinations of less than 10°.

[0057] The angle between the inclined surface P3 and the surface 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 flat surface PI and the inclined surface P3, both configured to be in contact with the electrical wire 24, creates an undercut preventing the electrical wire 24 from rising up the inclined surface P3, particularly during the operation of the rotor, thus reinforcing the retention of the electrical wire 24 at the bottom of the receiving groove 36.

[0058] In the embodiment considered, the inclined surface P3 is flat along its width and not flat along its length, so that it has a convex portion in contact with the electrical wire 24. This inclined surface P3 is therefore said here to be convex along its length and flat along its width. Alternatively, it could be concave along its width.

[0059] Thus, when the retaining wedge 30 is inserted into the bottom of the slot 16, the distance that the electrical wire 24 must travel in the bottom of the slot 16 to connect two adjacent poles is increased compared to the distance it would have to travel if the inclined surface P3 were flat. Advantageously, this allows the electrical wire 24 to be tightened in the bottom of the slot 16 and ensures better retention of the electrical wire 24 in the bottom of the slot 16 during the operation of the rotor 10.

[0060] Viewed along the normal to the axis of rotation Al, the edges formed by the junction of surfaces PI and P3, and the junction of surfaces P2 and P3 have a general V shape.

[0061] In a first possible embodiment (not shown), the retaining wedge 30 comprises at least two distinct parts, each carrying a portion of the apex 34. Each distinct part can be configured to be inserted into the bottom of the notch 16 from the same side 22 or 23 of the rotor 10. In the embodiment considered, the first part 30a of the retaining wedge 30 has an inclined surface, a portion of which is convex along its length on the side configured to be in contact with the wire, and the second part 30b has a flat inclined surface. In other words, in this first embodiment, the two parts could be formed by cutting the retaining wedge halfway along its length, as shown in [Fig. 4].

[0062] In a second possible embodiment illustrated in [Fig. 5], at least one of the two separate parts of the retaining wedge 30 is configured to be inserted axially through the side 22 of the rotor 10, and at least one other of the at least two separate parts of the retaining wedge 30 is configured to be inserted axially through the opposite side 23 of the rotor 10. In this second embodiment, the two separate parts 30a and 30b of the retaining wedge 30 are configured to grip the electrical wire 24 and prevent its centrifugation during the operation of the rotor 10. The separate parts 30a and 30b each have a receiving groove complementary to that of the other separate part, the electrical wire 24 bearing against the two receiving grooves. In other words, in this second embodiment, the two parts could be formed from the diagonal cut of the retaining wedge shown in [Fig. 5].4], except that the vertices of these two parts included . each two substantially flat surfaces PI, P2 joined together by an inclined surface P3 to delimit these two receiving grooves.

[0063] In the embodiment of [Fig. 4], the retaining wedge 30 does not have a plane of symmetry. In particular, if we consider a sagittal plane parallel to the longitudinal axis of this wedge and orthogonal to the substantially flat surfaces PI, P2, we observe that this wedge does not exhibit symmetry on either side of this plane. Consequently, the electrical wire can only pass on one side of this wedge. However, the winding of the electrical wire around the teeth occurs alternately in a clockwise direction and counterclockwise, so that the wire passes through the bottom of the inter-pole notch 16 alternately along one diagonal and the other diagonal. In other words, it is necessary to provide two separate references for the retaining wedges.

[0064] A third possible embodiment of the retaining wedge 30 is illustrated in [Fig. 6]. In this embodiment, only one wedge reference is required for the entire engine. The support vertex 34 therefore has a plane of sagittal symmetry. In this embodiment, the flat surface PI is surmounted by a promontory whose vertex forms the flat surface P2 and whose sides define two inclined surfaces P3a and P3b separated by a vertex 38, for example an edge, belonging to the plane of sagittal symmetry. The two inclined surfaces are convex since they have parallel first portions and inclined second portions that meet at vertex 38.

[0065] In this variant, two receiving grooves 36a and 36b are provided, located on either side of the apex 38. When the retaining wedge 30 is inserted into the bottom of the inter-pole notch 16, the electrical wire rests on one or the other of the two receiving grooves 36a, 36b, depending on the diagonal along which the electrical wire 24 extends into the bottom of the inter-pole notch 16. Advantageously, this variant allows only one set of wedges 30 to be used to lock and tighten the electrical wire 24 in all the bottoms of the inter-pole notch 16. To prevent wear on the electrical wire 24, the apex 38 can be chamfered or rounded.

[0066] In order to avoid wear on the electrical wire 24, the junction between the flat surface PI and the inclined surface P3 and / or the junction between the flat surface P2 and the inclined surface P3 can be machined, for example to present a chamfer or a rounded edge.

[0067] The invention also relates to a winding method for a wound rotor shown in [Fig. 7] and comprising, for at least two teeth 14: - a winding step S1 comprising: • a winding step S11 during which the already introduced wire The electrical wire 24 is wound around one of the teeth 14 to form a first coil of the wound rotor, and • a step of passing the electrical wire 24 from the first coil to an adjacent tooth 14, on which a coil of the wound rotor has not yet been formed, through the bottom of the inter-pole slot S12, and • a winding step S13 during which the electrical wire 24 is wound around the adjacent tooth 14 in order to form a second coil of the wound rotor, - a step S2 of positioning at least one retaining wedge 30 at the bottom of the inter-pole slot 16, such that the retaining wedge 30 is in lateral contact with the first tooth 14 by one side of the wedge and in lateral contact with the second tooth 14 by the side opposite the first side of the wedge.

[0068] During the winding step S1, the electrical wire 24 is wound around the first tooth in a trapezoidal manner so as to form a coil around this tooth and the end of the electrical wire 24 is at the exit of the coil at the level of the lowest layer of the coil in order to achieve the passage at the bottom of the inter-pole slot during step S12.

[0069] During this same winding step SI 1, at each turn of the conductor wire, for the first thickness of wire around the first tooth 14, the electrical wire 24 is applied taut along the entire length of one of the two axial faces of the tooth and parallel to the axis of rotation Al of the shaft. The electrical wire then rests against one of the two coil head guides, conforming to its shape until it reaches the other of the two axial faces of the tooth. Then the wire is applied taut along the entire length of the other of the two axial faces of the tooth and parallel to the axis of rotation Al of the shaft. The electrical wire then rests against the other of the two coil head guides, conforming to its shape until it reaches the first of the two axial faces of the tooth.

[0070] For each layer of turns, the first thickness of wire is made in the same way. For subsequent thicknesses of wire, the wire runs across two adjacent turns of the lower layer to minimize gaps.

[0071] During the step of passing through the bottom of the inter-pole slot S12, the electrical wire is passed from the coil formed during the previous step SI 1 to an adjacent tooth to be wound by connecting the opposite coil head guides of the two adjacent teeth. The passage of the electrical wire therefore occurs along one of the diagonals of the bottom of the inter-pole slot located between the two adjacent teeth.

[0072] During the winding step S13, the electric wire is wound around the tooth adjacent to the first tooth in a trapezoidal manner so as to form a coil around the second tooth and the end of the electric wire 24 is at the coil exit at the level of the lowest layer of the coil adjacent to the first coil.

[0073] During the S2 setup step, the retaining wedge 30 is inserted axially into the inter-pole notch 16 in contact with said tooth 14 and the adjacent tooth 14, the electrical wire 24 present in the inter-pole notch 16 bearing against the receiving groove 36 of the wedge 30.

[0074] In the embodiment considered, the rotor has an even number of teeth 14. Each retaining wedge 30 is inserted into the bottom of the inter-pole slot 16 by the end of the wound rotor shaft 10 opposite to the end of the wound rotor shaft 10 through which the wedges of the adjacent slot bottoms were inserted. In other words, the retaining wedges are inserted alternately in one direction and alternately in the opposite direction.

[0075] In the first variant, the first part (the one bearing the convex inclined surface) is inserted axially first and the second part is inserted axially second.

[0076] In the second variant, one of the at least two separate parts of the retaining wedge is inserted axially through a first side of the rotor and the other of the two separate parts of the retaining wedge is inserted axially through the opposite side of the rotor.

[0077] Preferably, steps S12 and S13 can be repeated on one or more other winding teeth of the rotor 10 before proceeding to step S2.

[0078] Once each tooth of the rotor has been wound, the electrical wire 24 is connected to the rotary commutator of the wound rotor by passing through the front of the coil head guide of the last wound tooth.

[0079] Preferably, the SI step is preceded by an S0 step during which a protective and electrical insulation paper is placed at the bottom of the inter-pole notch.

[0080] Finally, step S2 is followed by an impregnation step S4 during which a resin is applied to each shim inserted at the bottom of the inter-pole notch during step S2 as well as to the coils.

[0081] Advantageously, step S2 is preceded by a step during which a protective paper is placed on the windings made previously.

[0082] The present invention is in no way limited to the embodiment described and represented, but a person skilled in the art will be able to make any variation in accordance with the invention.

[0083] In a variant of the invention, the angle between the inclined surface P3 and the flat surface PI has a value greater than or equal to 90° and less than or equal to 120°.

[0084] In another embodiment of the invention, the surface P3 is curved along its length so that it has at least two convex portions adapted to come into contact with the electric wire 24.

[0085] In another embodiment of the invention, the substantially flat surfaces PI, P2 are joined to the surface P3 by an intermediate surface of rounded shape, so that no edge is formed between surfaces PI and P3 as well as between surfaces P2 and P3. As an example, the intermediate surface between PI and P3 is a fillet and the intermediate surface between P2 and P3 is a rounded edge.

[0086] In another variant of the invention, the inclined surface P3 consists of at least two distinct surfaces forming a non-zero angle between them.

[0087] In another embodiment of the invention, the coil 12 is formed from the rectangular and helical winding of the electric wire 24, forming a set of adjacent turns, around an axis which shall be defined as the axis of the coil. A rectangular winding is an ordered winding of the electric wire 24 around the tooth 14 and which has the same number of turns per layer from the top of the coil to the bottom of the coil 12.

[0088] In another embodiment of the invention, the coil 12 is formed from the rectangular and helical winding of the electric wire 24, forming a set of adjacent turns, around an axis which shall be defined as the axis of the coil. A rectangular winding is an ordered winding of the electric wire 24 around the tooth 14 and which has the same number of turns per layer from the top of the coil to the bottom of the coil 12.

[0089] In another embodiment of the invention, the coil 12 is formed from the disordered winding of the electric wire 24.

[0090] In another variant of the invention, the retaining wedge 30 comprises a profiled base 32a with a rectangular cross-section.

[0091] In another variant of the invention, the retaining wedge 30 comprises a profiled base 32a of cylindrical shape.

Claims

Claims

1. Holding wedge (30) for electric wire (24) in an inter-pole notch (16) of a wound rotor (10), comprising a body (32) which has a support top (34) for said electric wire (24), characterized in that said top delimits a receiving groove (36) for said electric wire (24).

2. Holding wedge (30) according to claim 1, in which the support top (34) comprises two substantially planar surfaces (PI, P2) offset and joined by an inclined surface (P3) having a non-zero angle with the substantially planar surfaces (PI, P2) in order to delimit with one of them said receiving groove (36).

3. Holding wedge (30) according to claim 2, in which the support top (34) has a plane of symmetry such that the receiving groove (36) is separated into two symmetrical parts.

4. Holding wedge (30) according to claim 2 or 3, in which the inclined surface (P3) extends in width between the two substantially planar surfaces (PI, P2) and in length in an orthogonal direction, the surface (P3) being curved along its length so that it has a convex portion adapted to come into contact with the electric wire (24).

5. Holding wedge (30) according to one of claims 2 to 4, in which the angle between the inclined surface (P3) and the flat surface (PI) has a value greater than or equal to 60° and less than or equal to 90°.

6. Holding wedge (30) according to one of claims 1 to 5, in which the body (32) comprises a profiled base (32a) of trapezoidal section and a head (32b) which has two parallel lateral faces and which carries the support top (34).

7. Holding wedge (30) according to one of claims 1 to 6, comprising at least two separate parts each carrying a part of the support top (34).

8. Holding wedge (30) according to one of claims 1 to 7, having a length between 10% and 150% of the length of a pole of the wound rotor (10).

9. Holding wedge (30) according to one of claims 1 to 8, having a chamfer at the junction between one or other of the substantially flat surfaces (P1, P2) and the inclined surface (P3).

10. Wound rotor comprising: - a longitudinal body (20), - teeth (14) distributed around the longitudinal body and defining between them inter-pole notches (16), and - an electric wire (24) wound around the teeth (14) to form windings (12) and part of which passes through one of the inter-pole notches (16), characterized in that it comprises at least one holding wedge (30) according to one of claims 1 to 9, said part of the electric wire (24) resting on the receiving groove (36) of the wedge.

11. Method of winding a wound rotor according to claim 10, comprising for at least two teeth (14): - a winding step (SI) comprising: H a step of winding (SI 1) the electric wire (24) around a first tooth (14), H a step of passing the electric wire (24) through the bottom of an inter-pole notch (S 12) towards an adjacent tooth to be wound, and H a step of winding (S 13) the electric wire (24) around the adjacent tooth (14) to be wound, - a step of placing (S2) at least one holding wedge (30) in the inter-pole notch (16) in contact with said first tooth and the adjacent tooth.

Images