Power supply device for a wound rotor

Abstract

Power supply device for a wound rotor. Power supply device for a wound rotor of an electric motor of a motor vehicle, comprising: - a rotor shaft (6B) including an axial opening (41B) and a radial opening (42B) communicating with the axial opening, - an axial electrical connection element (46B) including a slip ring (48B, 49B) and an axial conductor (51B), the axial conductor including a first end connected to the slip ring and a second end (52B), the axial element being positioned inside the axial opening (41B), and - a radial electrical connection element (47B) including a radial conductor (53B), the radial conductor including a first end (54B) connected to the second end (52B) of the axial conductor and an electrical connector (55B) intended to be connected to a first end of a coil of the wound rotor,The radial element is positioned inside the radial opening. See Figure 4 for the abbreviation.

Description

Title of the invention: Power supply device for a wound rotor Technical field of the invention

[0001] The invention relates to a power supply device for a wound rotor of an electric motor in a motor vehicle. The invention also relates to an electric motor for a motor vehicle comprising such a power supply device. The invention further relates to a method for manufacturing such a power supply device. Prior art

[0002] So-called "electric" or "hybrid" motor vehicles include an electric motor capable of driving the vehicle's drive wheels. Among the various types of electric motors available, wound-rotor electric motors are known. Such electric motors include a rotor equipped with at least one coil for which an electric current flows. To supply the at least one coil with electric current, a rotor shaft generally includes two slip rings cooperating with brushes. The two slip rings are connected by electrical wires to the two ends of the at least one coil.

[0003] The rotor shaft is guided in rotation by bearings, generally roller bearings. The bearings are arranged at the interface between an electric motor housing and the rotor shaft. The electrical wires connecting the slip rings to the coils pass through the central opening of an inner ring of the roller bearing.

[0004] Furthermore, since the rotor shaft is likely to rotate at very high speeds, for example, at over 10,000 revolutions per minute, the bearings are subjected to significant stress and must have an optimal geometry, free from any deformation. In addition, oil is present inside the housing to cool the electric motor and / or lubricate the bearings. Sealing devices must therefore be provided at the interface between the housing and the rotor shaft to prevent any oil leakage.

[0005] Thus, the architecture of a wound rotor shaft is complex since it must accommodate the power supply to at least one coil, while also cooperating with bearings and sealing means. Furthermore, the assembly process for a wound rotor must be as simple as possible. Finally, an electric motor comprising such a wound rotor must be compact, reliable, and quiet. Presentation of the invention

[0006] The object of the invention is to provide an electric motor for a motor vehicle comprising a wound rotor remedying the above disadvantages and improving upon known electric motors of the prior art.

[0007] More specifically, a first object of the invention is a power supply device for a wound rotor of an electric motor which is both simple and allows for reliable operation of the electric motor even when the wound rotor rotates at high speed. Summary of the invention

[0008] The invention relates to a power supply device for a wound rotor of an electric motor of a motor vehicle, the power supply device comprising: - a rotor shaft comprising an axial opening and at least one radial opening distinct from the axial opening and communicating with the axial opening, - an axial electrical connection element comprising at least one slip ring and at least one axial conductor, the at least one axial conductor comprising a first end connected to the at least one slip ring and a second end, the axial element being positioned inside said axial opening, and - at least one radial electrical connection element comprising a radial conductor, the radial conductor comprising a first end connected to the second end of the axial conductor and an electrical connector intended to be connected to a first end of a coil of the wound rotor, the at least one radial element being positioned inside said at least one radial opening.

[0009] The at least one radial opening of the rotor shaft may comprise a first radial opening and a second radial opening, the first radial opening being distinct from the second radial opening. The axial element may comprise a first slip ring, a second slip ring, a first axial conductor, and a second axial conductor, the first axial conductor comprising a first end connected to the first slip ring and a second end, the second axial conductor comprising a first end connected to the second slip ring and a second end.The at least one radial element may comprise a first radial element and a second radial element, the first radial element comprising a first radial conductor, the first radial conductor comprising a first end connected to the second end of the first axial conductor and an electrical connector intended to be connected to a first end of a coil of the wound rotor, the second radial element comprising a second radial conductor, the second radial conductor comprising a first end connected to the second end of the second. axial conductor and an electrical connector intended to be connected to a second end of the wound rotor coil, the first radial element being positioned inside the first radial opening, the second radial element being positioned inside the second radial opening.

[0010] The axial element may comprise an axial body made of insulating material, in particular plastic, with at least one slip ring arranged around a part of the axial body, at least one axial conductor being partially embedded inside the axial body, the second end of at least one axial conductor being free from the axial body.

[0011] The at least one radial element may comprise a radial body made of insulating material, in particular plastic, the radial conductor of the at least one radial element being partially embedded inside the radial body, the first end and the second end of the radial conductor being free from the radial body.

[0012] At least one axial conductor of the axial element may be in axial electrical contact with the radial conductor of at least one radial element. Alternatively, at least one axial conductor of the axial element may be in radial electrical contact with the radial conductor of at least one radial element.

[0013] The radial conductor may comprise a radially elastic and conductive means, the second end of the radial conductor being connected to the first end of the radial conductor via said elastic means, the elastic means being under tension to ensure electrical contact between the first end of the radial conductor and the second end of the axial conductor

[0014] The axial conductor may include an axially elastic and conductive means, the second end of the axial conductor being connected to the first end of the axial conductor by means of said axially elastic means, the axially elastic means being under tension to ensure electrical contact between the first end of the radial conductor and the second end of the axial conductor.

[0015] The second end of the axial conductor may include a hole, the first end of the radial conductor being inserted inside said hole and in contact with the edges of said hole. Alternatively, the first end of the radial conductor may include a hole, the second end of the axial conductor being inserted inside said hole and in contact with the edges of said hole.

[0016] The power supply device may include a bearing supporting the rotor shaft, in particular a bearing with rollers, the bearing being arranged on a first cylindrical bearing surface formed on the rotor shaft, said first bearing surface extending between an inlet of at least one radial opening and an inlet of the axial opening.

[0017] The power supply device may include a dynamic sealing means, the dynamic sealing means being in dynamic contact with a second cylindrical bearing surface formed on the rotor shaft, said second cylindrical bearing surface extending between an inlet of at least one radial opening and an inlet of the axial opening.

[0018] The power supply device may include a static sealing means arranged between an inner edge of the axial opening and an outer edge of the axial element.

[0019] The power supply device may include a retaining ring bearing against at least one radial element to hold at least one radial element in the radial opening.

[0020] The invention also relates to an electric motor for a motor vehicle comprising a wound rotor equipped with at least one coil and an electrical power supply device as defined above, the electrical power supply device being configured to electrically supply at least one coil of the wound rotor.

[0021] The invention also relates to a method for manufacturing a power supply device as defined above, the method comprising: - supplying a rotor shaft comprising an axial opening and at least one radial opening distinct from the axial opening and communicating with the axial opening, - the supply of an axial electrical connection element comprising at least one slip ring and at least one axial conductor, the at least one axial conductor comprising a first end connected to at least one slip ring and a second end, - the supply of at least one radial electrical connection element comprising a radial conductor, the radial conductor comprising a first end and a second end, the second end being intended to be connected to a first end of a coil of a wound rotor, then - the insertion of the axial element into the axial opening, and - the insertion of at least one radial element into at least one radial opening, then - the connection between the first end of the radial conductor of at least one radial element and the second end of the axial conductor. Presentation of the figures

[0022] These objects, features and advantages of the present invention will be described in detail in the following description of various particular embodiments presented by way of non-limiting agreement, in relation to the accompanying figures, among which:

[0023] Fig. 1 is a schematic radial cross-sectional view of part of an electric motor according to a first embodiment.

[0024] Fig. 2 is a perspective view of part of a rotor of the electric motor of Fig. 1.

[0025] Fig. 3 is a perspective view of an electrical connection element of the electric motor of Fig. 1.

[0026] Fig. 4 is a schematic radial cross-sectional view of part of an electric motor according to a second embodiment.

[0027] Fig. 5 is a schematic radial cross-sectional view of part of an electric motor according to a third embodiment.

[0028] Fig. 6 is a schematic radial cross-sectional view of part of an electric motor according to a fourth embodiment.

[0029] Fig. 7 is a schematic axial cross-sectional view of a part of the electric motor according to the fourth embodiment.

[0030] The [Fig.8] is a schematic front view of one end of an electrical conductor of a connection element of the electric motor according to the fourth embodiment. Detailed description

[0031] Figure 1 illustrates, by way of a cross-sectional view, a first embodiment of an electric motor IA. The electric motor IA is intended to drive the drive wheels of a motor vehicle. The electric motor IA can, for example, be powered by an electric battery, in particular a lithium-ion battery. The electric motor IA comprises a housing 2A, a stator 3A fixed rigidly to the housing 2A, and a rotor 4A free to rotate relative to the housing 2A and the stator 3A about an axis of rotation X.

[0032] An axial direction is defined as a direction parallel to the axis of rotation X. A radial direction is defined as a direction perpendicular to the axis of rotation X and passing through the axis of rotation X. A radial direction is notably illustrated by arrow Y in [Fig. 1]. A radial cut is a cut made parallel to the axis of rotation X. An axial cut is a cut made perpendicular to the axis of rotation X.

[0033] The rotor 4A is a wound rotor, that is, it comprises at least one coil 5A, or winding of an electric wire. The coil 5A is intended to carry an electric current. The flow of an electric current in the coil 5A produces a magnetic field capable of interacting with the stator 3A, leading to rotation of the rotor 4A about the axis of rotation X. The rotor 4A comprises a rotor shaft 6A and a ferromagnetic core 7A, both clearly visible in [Fig. 2]. The core The ferromagnetic core 7A comprises a set of radial protrusions 8A, notably with a "T"-shaped cross-section, around which the coils 5A are formed. According to the embodiment illustrated in [Fig. 2], the ferromagnetic core 7A comprises four radial protrusions 8A. Alternatively, this number could be different.

[0034] According to the embodiment presented, the electric motor IA is of the radial flux type, meaning that the magnetic flux between the stator 3A and the rotor 4A is oriented radially. Alternatively, the invention could be adapted to an axial flux type motor, that is, an electric motor in which the magnetic flux is oriented parallel to the axis of rotation X.

[0035] The rotor shaft 6A comprises two opposing ends. One end includes a rotational drive means, in particular splines 9A. The rotational drive means is intended to be mechanically coupled to a transmission system to drive the vehicle's drive wheels. A second end of the rotor shaft 6A, particularly visible in [Fig. 1], accommodates an electrical connection element 10A configured to supply electric current to the coils 5A.

[0036] The second end of the shaft 6A comprises a first portion 1 IA, a second portion 12A, and a third portion 13A. The three portions 11A, 12A, and 13A are generally cylindrical in shape. A diameter of the first portion is strictly greater than a diameter of the second portion. A diameter of the second portion is strictly greater than a diameter of the third portion. Furthermore, the second end of the rotor shaft 6A comprises two notches 14A, 15A, notably diametrically opposed, parallel to the axis of rotation X, and extending along the first portion 1 IA and the second portion 12A.

[0037] The electrical connection element 10A is shown in isolation in [Fig. 3]. The electrical connection element 10A comprises a first slip ring 16A and a second slip ring 17A. The two slip rings 16A and 17A cooperate with two brushes 18A and 19A (visible in [Fig. 1]) respectively to collect an electric current. The two slip rings may, for example, be made of copper. The two slip rings 16A and 17A are arranged on a body 20A of the electrical connection element 10A. The body 20A is made of an electrically insulating material, in particular plastic. The electrical connection element 10A also comprises a first electrical connector 21A and a second electrical connector 22A. The two electrical connectors 21A and 22A are electrically connected to two ends of at least one 5A coil.Electrical connectors 21A and 22A can be crimped around two ends of an electrical wire from coil 5A. In [Fig. 3], electrical connectors 21A and 22A are shown. are presented in a crimping-ready state. The two electrical connectors, 21A and 22A, extend radially. The 10A electrical connection element also includes a first 23A electrical conductor and a second 24A electrical conductor. The first 23A electrical conductor electrically connects the first 16A slip ring to the first 21A electrical connector. The second 24A electrical conductor electrically connects the second 17A slip ring to the second 22A electrical connector.

[0038] The body 20A comprises a tubular portion around which the two slip rings 16A and 17A are arranged. Static sealing means, in particular O-rings 25A, are also arranged around this tubular portion. The tubular portion is then extended by two radial arms 26A, 27A, in particular diametrically opposed, within which the first conductor 23A and the second conductor 24A extend respectively. The two radial arms are connected by an annular ring 28A.

[0039] The electrical connection element 10A is assembled to the rotor shaft 4A so that the two radial arms 26A, 27A are positioned respectively in the two notches 14A, 15A. The tubular part of the body 20A supporting the two slip rings 16A and 17A and the O-rings 25A thus extends to the height of the first portion 1 IA of the rotor shaft 6A.

[0040] The rotor shaft 6A is supported and guided in rotation by a bearing 29A. The bearing 29A is arranged at the interface between the rotor shaft 6A and the housing 2A. The bearing 29A includes an inner ring 30A mounted on the second portion 12A of the rotor shaft 6A. Since the second portion 12A is interrupted by notches 14A and 15A, the inner ring 30A does not have continuous support around its entire circumference. The radial arms 26A, 27A do not support, or only minimally support, the inner ring 30A. The radial arms 26, 27A may not be in contact with the inner ring 30A. The absence of support for the inner ring 30A at the notches 14A and 15A can lead to a lack of circularity of the inner ring 30A, and therefore to undesirable noises when the rotor shaft rotates at high speed.

[0041] Furthermore, the electric motor IA also includes a dynamic sealing means 31A arranged at an interface between the housing 2A and the inner ring 30A. The inner ring therefore comprises, on the one hand, a raceway cooperating with the bearings of the roller bearing housing 29A, and on the other hand, an external bearing surface in contact with the sealing means 31A. The inner ring 30A of the roller bearing housing 29A is wider than the outer ring of this bearing along the axis of rotation X.

[0042] Furthermore, the O-rings 25A are in contact with a bore of the inner ring 30A. Finally, secondary sealing means, in particular seals Secondary toroidal 32A are provided at the interface between the second end of the rotor shaft 4A and a bore of the electrical connection element 10A.

[0043] According to this first embodiment, a simple and compact power supply device is provided for the coils of a wound rotor. However, the lack of uniform support for the inner ring 30A of the bearing housing 29A can lead to undesirable operating noise and / or degradation of the sealing provided by the sealing means 31 A.

[0044] Figure 4 schematically illustrates a second embodiment of an electric motor IB. To describe this second embodiment, the same reference numerals are used as for the first embodiment described above, but replacing the suffix "A" with the suffix "B". To simplify the description, the differences between the first and second embodiments will be described primarily, without repeating the common features.

[0045] As in the first embodiment, the electric motor IB also comprises a housing 2B, a stator, a wound rotor equipped with at least one coil, and a rotor shaft 6B. Unlike the rotor shaft 6A, the rotor shaft 6B is not notched. Furthermore, the electric motor IB includes a bearing, in particular a roller bearing 29B, arranged at the interface between the rotor shaft 6B and the housing 2B. An inner ring 30B of the roller bearing is fitted onto a first cylindrical bearing surface 33B of the rotor shaft 6B. This first bearing surface 33B is not interrupted by a notch. The inner ring 30B is therefore not at risk of deformation.

[0046] The electric motor IB also includes a dynamic sealing means 31B, in particular a dynamic seal, arranged at an interface between the housing 2B and the rotor shaft 6B. The seal is in dynamic contact with a second cylindrical bearing surface 34B formed on the rotor shaft 6B. By "dynamic contact," it is understood that the second bearing surface 34B is intended to rotate relative to the sealing means. There is therefore a sliding contact between the seal and the second bearing surface 34B.

[0047] The rotor shaft 6B includes an axial opening 41B, a first radial opening 42B, and a second radial opening (not shown). The axial opening 41B extends parallel to the axis of rotation X. It includes an inlet 43B positioned on an end face 35B of the rotor shaft. The inlet 43B extends parallel to the axis of rotation X. The first radial opening 42B extends parallel to a radial direction Y. It includes an inlet 44B positioned on a cylindrical circumference of the rotor shaft. The second radial opening can be diametrically opposite the first radial opening 42B, and therefore also positioned on the cylindrical circumference of the rotor shaft. The axial opening 41B can be obtained by drilling the rotor shaft 6B parallel to the axis of rotation X. The radial openings can be obtained by drilling the rotor shaft 6B perpendicular to the axis of rotation X.

[0048] The radial openings are distinct from the axial opening; that is, these openings have separate inlets. In contrast, the radial openings communicate with the axial opening. The rotor shaft 6B therefore includes a junction zone 45B that belongs to both the radial openings and the axial opening. The rotor shaft 6B is a monolithic part; that is, it is formed from a single piece in which the openings are formed. The rotor shaft 6B is not the result of assembling several rotor shaft parts.

[0049] The bearing surfaces 33B and 34B extend between the radial openings and the end face 35B of the rotor shaft from which the axial opening extends. In other words, the inlets of the radial openings are separated from the inlet of the axial opening by the bearing surfaces 33B and 34B.

[0050] According to this second embodiment, a power supply device for at least one coil of the wound rotor is formed by assembling several separate connecting elements. In particular, a power supply device for the coils of the electric motor IB comprises an axial element 46B, a first radial element 47B, and a second radial element (not shown). The axial element 46B is positioned inside the axial opening 41B. The first radial element 47B is positioned inside the first radial opening 42B. The second radial element is positioned inside the second radial opening.

[0051] The axial element 46B comprises a first slip ring 48B, a second slip ring 49B, a first axial conductor 51B, and a second axial conductor (not shown). The first axial conductor 51B has a first end connected to the first slip ring 48B. Note that two elements are said to be "connected" when they are electrically connected to each other, that is, in contact allowing the passage of an electric current between them. The first axial conductor 51B also has a second end 52B opposite the first end. Similarly, the second axial conductor has a first end connected to the second slip ring and a second end opposite its first end.

[0052] The first radial element 47B comprises a first radial conductor 53B. The first radial conductor 53B comprises a first end 54B connected to the second end 52B of the first axial conductor 51B. The first radial conductor 53B also comprises a first electrical connector 55B connected to a first end of at least one coil of the wound rotor. Similarly, the second The radial element includes a second radial conductor. The second radial conductor has a first end connected to the second end of the second axial conductor. The second radial conductor also includes a second electrical connector connected to a second end of at least one coil of the wound rotor.

[0053] Generally, the second axial conductor cooperates with the second radial conductor in a manner analogous to the first axial conductor with the first radial conductor. To simplify the description, the design of the second radial connecting element will not be further described but can be deduced by those skilled in the art from the design of the first radial connecting element, particularly by axial symmetry.

[0054] The axial element 46B comprises an axial body 56B made of insulating material, in particular plastic. The axial body 56B may have a tubular shape whose axis of revolution coincides with the axis of rotation X. The slip rings 48B, 49B are arranged side by side around a portion of the axial body 56B. The first axial conductor 51B and the second axial conductor are partially embedded within the axial body 56B. The second end 52B of the first axial conductor is free from the axial body 56B. In particular, the second end 52B protrudes parallel to the axis of rotation X in the direction of the first end 54B of the first radial conductor 53B.

[0055] The axial body 56B advantageously carries at least one static sealing means 57B, for example two O-rings, cooperating with an inner edge of the axial opening. The at least one sealing means 57B is therefore arranged between an inner edge of the axial opening 41B and an outer edge of the axial body 56B.

[0056] Similarly, the first radial element 47B comprises a radial body 58B made of insulating material, in particular plastic. The first radial conductor 53B is partially embedded within the radial body 58B. The first and second ends of the first radial conductor are free from the radial body 58B. The second end of the first radial conductor 53B carries the first electrical connector 55B. As explained previously, the first end 54B of the first radial conductor 53B is in contact with the second end 52B of the first axial conductor 51B. More precisely, the axial conductor 51B is in axial contact with the first radial conductor 53B, that is, the contact between these two conductors is established in a plane perpendicular to the axis of rotation X.

[0057] The radial body 58B advantageously includes a stop means 59B cooperating with the rotor shaft 6B, in particular with an edge of the first radial opening 42B or a counterbore formed around the first radial opening, to define the position of the first radial element within the first radial opening.

[0058] To assemble the power supply device according to the second embodiment, the rotor shaft 6B, the axial element 46B, and the two radial elements 47B are first provided. Each radial element is then inserted into its corresponding radial opening until the stop means 59B makes contact with the rotor shaft 6B. Next, the axial element is inserted into the axial opening at least until the conductors of the axial element make contact with the conductors of the radial elements. Deformation of these conductors is possible during the assembly process to ensure proper electrical contact between the conductors.

[0059] Each radial element may have a shape complementary to the shape of the radial opening into which it is inserted. Alternatively, each radial opening could have a larger dimension than the corresponding radial element so as to allow some mobility of the radial element within the corresponding radial opening. This can facilitate crimping the connectors at the ends of the coil. Once the crimping operation has been completed, the radial element can be secured within the corresponding radial opening, for example, by means of a wedge or a locking ring.

[0060] According to an alternative embodiment not shown, the rotor shaft 6B could comprise only a single radial opening, and the two radial elements could be inserted side-by-side in this single radial opening. The two radial elements could even form a single part comprising a single body made of insulating material, through which two radial conductors pass.

[0061] Figure 5 schematically illustrates a third embodiment of an electric motor IC. To describe this third embodiment, the same reference numerals are used as for the first and second embodiments described above, but replacing the suffixes "A" or "B" with the suffix "C". To simplify the description, the differences between the third and second embodiments will be described primarily, without repeating the common features.

[0062] The third embodiment differs from the second embodiment primarily in that the axial conductor 51C is in radial contact with the first radial conductor 53C, and not in axial contact. That is to say, the contact between the two conductors 51C and 53C is established on a surface parallel to the axis of rotation X.

[0063] Advantageously, the axial body 56C then includes a stop means 60C cooperating with the rotor shaft 6B, in particular with an edge of the axial opening 41C, to define the position of the axial element within the axial opening.

[0064] Furthermore, according to the third embodiment, each radial conductor 53C comprises an elastic means 61C. The elastic means 61 is radially elastic, That is to say, it is configured to elastically change its length in the radial direction. Furthermore, the elastic means 61C is made of an electrically conductive material. The two ends of each radial conductor 53C are connected to each other via the elastic means 61C. The elastic means 61C is designed to be tensioned to ensure electrical contact between each radial conductor and its corresponding axial conductor. The elastic means 61C can be, for example, a helical spring made of an electrically conductive material, for example, copper. Such a helical spring can be held within a housing provided in the radial body 58C.

[0065] As a side note, such a conductive elastic means could also be provided in the axial conductors 51B of the second embodiment. In this case, the second end 52B of the axial conductor 51B would be connected to the first end of the axial conductor via an axially elastic means. The axially elastic means would also be under tension to ensure electrical contact between the first end of the radial conductor and the second end of the axial conductor.

[0066] To assemble the feeding device according to the third embodiment, the rotor shaft 6C, the axial element 46C, and the two radial elements 47C are first provided. Next, the axial element 46C is inserted into the axial opening. The axial element is inserted into the axial opening until the stop means 60C comes into contact with the rotor shaft 6C. Then, each radial element is inserted into its corresponding radial opening. Each radial element is inserted into its corresponding radial opening until the stop means 59C comes into contact with the rotor shaft 6C. During the insertion of the radial elements, their respective elastic means 61C are tensioned. The order of insertion of the radial and axial elements is therefore reversed compared to the second embodiment.

[0067] Figures 6 and 7 schematically illustrate a fourth embodiment of a 1D electric motor. To describe this fourth embodiment, the same reference numerals are used as for the first, second, and third embodiments described above, but replacing the suffixes "A", "B", or "C" with the suffix "D". To simplify the description, the differences between the fourth and third embodiments will be primarily described, without repeating the common features.

[0068] The fourth embodiment differs from the third embodiment primarily in that the axial conductor 51D comprises a hole 62D, and in that the radial conductor 58D passes through this hole and is in contact with its edges. The hole 62D is formed in the second end 52D of the axial conductor 51D. Advantageously, the hole 62D is a hole with deformable edges, that is to say that the edges of hole 62D are designed to deform when radial conductor 58D is pushed through hole 62D.

[0069] An embodiment of a hole 62D with deformable edges is illustrated in [Fig. 8]. The hole 62D comprises a central circular opening 63D extended by a plurality of notches 64D, in this case four notches 64D. The notches 64D define lobes 65D, in this case four lobes 65D. The diameter of the central opening 63D may be slightly smaller than a diameter of the radial conductor 58D. When the radial conductor is brought close to the hole 62D, it exerts pressure on the lobes 65D, which deform to enlarge the diameter of the central opening 63D. The lobes 65D can then grip the radial conductor 58D, thereby holding the radial conductor captive. This solution has the advantage of ensuring good electrical contact between the axial conductor 51D and the radial conductor 58D. Furthermore, the radial element 47D is effectively held in place in its radial opening by means of the axial conductor.The risk of ejection of the radial element under the effect of centrifugal force is therefore reduced. Advantageously, the axial element 46D can include a stiffening reinforcement to prevent its deformation when the radial conductor 58D is pushed into the hole 62D.

[0070] As illustrated in [Fig. 6], a retaining means, in particular a locking ring 66D, may be provided, exerting a reaction force on the radial elements 47D. The locking ring 66D may have an annular shape centered on the axis of rotation X. The locking ring 66D may include an axial bearing surface against the inner ring 30 of the bearing housing 29C. The locking ring 66D is intended to prevent the ejection of the radial elements under the effect of centrifugal force. The locking ring 66D may bear against the radial body of each radial element 47D. Such a retaining means can, of course, be adapted to retain the radial elements 47B, 47C according to the other embodiments described.

[0071] To assemble the power supply device according to the fourth embodiment, the procedure is substantially the same as for the third embodiment. The rotor shaft 6D, the axial element 46D, and the radial elements 47D are provided. The axial element 46D is inserted first into the axial opening, and then the radial elements into their respective radial openings. During the insertion of the radial elements, the radial conductors 58D enter the holes 62D.

[0072] According to a fifth embodiment, not shown, the radial conductor includes a hole, and the axial conductor passes through this hole. The hole is then formed in the first end of the radial conductor. Similarly, the hole formed in the radial conductor may advantageously be a hole with deformable edges. Such an embodiment also very effectively retains the radial elements against the centrifugal force. To assemble the feeding device according to the fifth embodiment, the radial elements are first inserted into their respective radial openings, and then the axial element is inserted into the axial opening. This fifth embodiment is essentially a combination of the second and fourth embodiments.

[0073] Finally, thanks to the invention, a power supply device for a wound rotor of an electric motor of a motor vehicle is available, which is simple to manufacture and assemble. The power supply device allows the coils of the wound rotor to be powered without disrupting the proper functioning of a bearing supporting the rotor shaft and / or a sealing means at the interface between the housing and the rotor shaft.

Claims

Demands

1. Power supply device for a wound rotor of an electric motor of a motor vehicle, characterized in that it comprises: - a rotor shaft (6B) including an axial opening (41B) and at least one radial opening (42B) separate from the axial opening and communicating with the axial opening, - an axial electrical connection element (46B) including at least one slip ring (48B, 49B) and at least one axial conductor (51B), the at least one axial conductor including a first end connected to the at least one slip ring and a second end (52B), the axial element being positioned inside said axial opening (41B), and - at least one radial electrical connection element (47B) including a radial conductor (53B),the radial conductor comprising a first end (54B) connected to the second end (52B) of the axial conductor and an electrical connector (55B) intended to be connected to a first end of a coil of the wound rotor, at least one radial element being positioned inside said at least one radial opening.

2. Power supply device according to the preceding claim, characterized in that: - at least one radial opening of the rotor shaft comprises a first radial opening (42B) and a second radial opening, the first radial opening being distinct from the second radial opening, - the axial element (46B) comprises a first slip ring (48B), a second slip ring (49B), a first axial conductor (51B), and a second axial conductor, the first axial conductor comprising a first end connected to the first slip ring and a second end (52B), the second axial conductor comprising a first end connected to the second slip ring and a second end, and - at least one radial element comprises a first radial element (47B) and a second radial element, the first radial element comprising a first radial conductor (53B),the first radial conductor comprising a first end (54B), connected to the second end of the first axial conductor and an electrical connector (55B) intended to be connected to a first end of a wound rotor coil, the second radial element comprising a second radial conductor, the second radial conductor comprising a first end connected to the second end of the second axial conductor and an electrical connector intended to be connected to a second end of the wound rotor coil, the first radial element being positioned inside the first radial opening (42B), the second radial element being positioned inside the second radial opening.

3. Power supply device according to any one of the preceding claims, characterized in that: - the axial element (43B) comprises an axial body (56B) made of insulating material, in particular plastic, at least one slip ring (48B, 49B) being arranged around a part of the axial body, at least one axial conductor (51B) being partially embedded inside the axial body, the second end (52B) of at least one axial conductor being free from the axial body, and / or in that - at least one radial element (47B) comprises a radial body (58B) made of insulating material, in particular plastic, the radial conductor (53B) of at least one radial element being partially embedded inside the radial body, the first end and the second end of the radial conductor being free from the radial body.

4. Power supply device according to any one of the preceding claims, characterized in that: - at least one axial conductor (51B) of the axial element (46B) is in axial electrical contact with the radial conductor (53B) of at least one radial element (47B), or in that - at least one axial conductor (51C) of the axial element (46C) is in radial electrical contact with the radial conductor (53C) of at least one radial element (47C).

5. A power supply device according to any one of the preceding claims, characterized in that: - the radial conductor (53C) comprises a radially conductive elastic means (61C), the second end of the radial conductor being connected to the first end of the radial conductor via said elastic means, the elastic means being under tension to ensure electrical contact between the first the radial conductor end and the second end of the axial conductor, and / or in that - the axial conductor comprises an axially elastic and conductive means, the second end of the axial conductor being connected to the first end of the axial conductor by means of said axially elastic means, the axially elastic means being under tension to ensure electrical contact between the first end of the radial conductor and the second end of the axial conductor.

6. Power supply device according to any one of the preceding claims, characterized in that: - the second end (52D) of the axial conductor (51D) comprises a hole (62D), the first end of the radial conductor (58D) being inserted inside said hole and in contact with edges of said hole, or in that - the first end of the radial conductor comprises a hole, the second end of the axial conductor being inserted inside said hole and in contact with edges of said hole.

7. Power supply device according to any one of the preceding claims, characterized in that it comprises a bearing (29B) supporting the rotor shaft (6B), in particular a bearing with rollers, the bearing being arranged on a first cylindrical bearing surface (33B) formed on the rotor shaft, said first bearing surface extending between an inlet (44B) of at least one radial opening (42B) and an inlet (43B) of the axial opening (41B).

8. Power supply device according to any one of the preceding claims, characterized in that it comprises: - a dynamic sealing means (31B), the dynamic sealing means being in dynamic contact with a second cylindrical bearing surface (34B) formed on the rotor shaft (6B), said second cylindrical bearing surface extending between an inlet (44B) of at least one radial opening (42B) and an inlet (43B) of the axial opening (41B), and / or - a static sealing means (57B) arranged between an inner edge of the axial opening (41B) and an outer edge of the axial element (46B).

9. A power supply device according to any one of the preceding claims, characterized in that it comprises a retaining ring (66D) supported against at least one radial element (47D) to hold at least one radial element in the radial opening.

10. Electric motor (IB, IC, 1D) for a motor vehicle comprising wound rotor equipped with at least one coil and an electric power supply device according to any one of the preceding claims, the electric power supply device being configured to electrically supply at least one coil of the wound rotor.

11. A method for manufacturing an electrical power supply device according to any one of claims 1 to 9, characterized in that it comprises: - providing a rotor shaft (6B) comprising an axial opening and at least one radial opening distinct from the axial opening and communicating with the axial opening, - providing an axial electrical connection element (46B) comprising at least one slip ring and at least one axial conductor, the at least one axial conductor comprising a first end connected to the at least one slip ring and a second end, - providing at least one radial electrical connection element (47B) comprising a radial conductor, the radial conductor comprising a first end and a second end, the second end being intended to be connected to a first end of a coil of a wound rotor, and then - inserting the axial element into the axial opening,and - the insertion of at least one radial element into at least one radial opening, then - the connection between the first end of the radial conductor of at least one radial element and the second end of the axial conductor.

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