Wound rotor of an electric machine equipped with electrical connection devices

Abstract

Wound rotor of an electric machine equipped with electrical connection devices. The present invention relates to a rotor (1) for an electric machine, comprising a rotating shaft (100), a rotor body comprising at least one winding (200), and electrical connection devices for electrically connecting the ends of the rotor winding (1) to a rotor excitation system (1). The rotor (1) is characterized in that at least one of the electrical connection devices comprises a radial connector (500) disposed in a radial recess of the rotating shaft (100) and an axial connector (700) disposed in an axial recess of the rotating shaft (100), and in that the rotor (1) further comprises means for attaching the radial connector (500) to the axial connector (700). (Figure 10)

Description

Title of the invention: Wound rotor of an electric machine equipped with electrical connection devices

[0001] The present invention relates to the fields of electrotechnics and automotive engineering, and more specifically concerns a wound rotor of an electric machine, finding a particular application in the automotive field.

[0002] Electric or hybrid vehicles are equipped with electric machines that provide torque to the wheels of these vehicles. Some of these electric machines use wound rotors rather than permanent magnet rotors, wound rotors having the advantage of not using rare earth elements and not having magnetic poles that demagnetize during the operation of the electric machines comprising them, when their temperature rises.

[0003] A wound rotor nevertheless requires coupling to an electrical excitation system for this wound rotor, and therefore requires an electrical connection between the ends of the rotor windings and the excitation system. This system uses, for example, carbon brushes rubbing against copper rings fixed to one end of a rotating rotor shaft. In order to electrically connect the end of the rotating rotor shaft to the ends of the rotor windings, while protecting the electrical conductors providing this connection, an overmolding of these electrical conductors is generally used.

[0004] The electrical conductors thus overmolded are, for example, arranged in grooves machined axially in a bearing of the rotating shaft, and pass under the inner ring of a bearing in which the rotating shaft is mounted for rotation, the outer ring of the bearing being integral with a fixed part of the electrical machine comprising the wound rotor. However, such an arrangement deforms the bearing and generates acoustic excitation of the electrical machine.

[0005] Another solution consists of threading the electrical conductors through holes in the rotating shaft, so as not to alter the cylindrical surface of the rotating shaft supporting the bearing in which it is mounted for rotation, and then injecting resin into these holes to electrically insulate the electrical conductors from the rotating shaft, which is generally made of steel. However, such electrical insulation is difficult and expensive to achieve.

[0006] The present invention aims to remedy at least partially the aforementioned drawbacks by providing a wound rotor for an electric machine and a method for connecting the ends of the windings of such a rotor to a rotor excitation system, which allow a cylindrical surface of a rotating rotor shaft, intended to receive a bearing, to remain undeformed, while being simple and inexpensive to manufacture.

[0007] To this end, the invention proposes a rotor for an electric machine, comprising a rotating shaft, a rotor body comprising at least one winding, and electrical connection devices intended to electrically connect the ends of the rotor winding to a rotor excitation system, the rotor being characterized in that at least one of the electrical connection devices comprises a radial connector disposed in a radial recess of the rotating shaft and an axial connector disposed in an axial recess of the rotating shaft, and in that the rotor further comprises means for fixing the radial connector to the axial connector.

[0008] It should be noted that in this patent application, the term "axial" refers, unless otherwise stated, to a direction parallel to the axis of rotation of the electric machine's rotor. Similarly, the term "radial" refers, unless otherwise stated, to a direction orthogonal to and intersecting the axis of rotation of the electric machine's rotor, while the terms "angular" or "ortho-radial" refer, unless otherwise stated, to a direction orthogonal to the axial direction and to a radial direction, this orthogonal direction being in fact rotating about the rotor's axis of rotation.

[0009] The electrical connection devices for the wound rotor according to the invention electrically connect, once the rotor is mounted in the electric machine, the ends of the rotor winding(s) to an electrical connection system for the rotor excitation system. This electrical connection system is mounted on one end of the rotating shaft of the rotor and consists, for example, of copper rings adapted to cooperate with carbon brushes of the excitation system. The electrical connection system is located axially opposite the ends of the windings with respect to a cylindrical surface of the rotating shaft that receives a bearing in which the rotating shaft is mounted. The ends of the windings are the ends of one or more wires forming the windings or of electrical conductors connecting several winding wire ends together.

[0010] Of course other electrical connection systems can be used at the end of the rotating shaft, for example metal discs capacitively coupled to the rotor excitation system.

[0011] Thanks to the invention, it is not necessary to pass electrical wires forming bends through a rotating shaft, since two connectors are used for one end of the winding to be connected to the excitation system, each connector being able to be inserted without deformation by a simple translation into a radial or axial recess in the rotating shaft of the rotor. The radial recess naturally intersects the axial recess. This design makes it much easier to isolate the electrical conductors of the two connectors from the rotating shaft.

[0012] Finally, the invention makes it possible to mount the rotating rotor in a bearing located around an axial recess of the rotating shaft, without modifying the cylindrical surface of the rotating shaft on which the inner ring of the bearing is arranged.

[0013] Preferably, all electrical connection devices for the rotor, intended to electrically connect the ends of the rotor windings to a rotor excitation system, are designed identically, but are angularly offset on the rotating rotor shaft. In particular, for a rotor according to the invention supplied with direct current and having only two winding ends to be connected to the excitation system, the rotor has only two identical electrical connection devices arranged 180° apart on the rotating rotor shaft.

[0014] According to an optional and advantageous feature of the invention, the radial connector comprises an electrical conductor and a body that electrically insulates the electrical conductor from the rotating shaft. This insulating body is, for example, a cylindrical overmolding around a portion of the electrical conductor of the radial connector, providing a non-zero insulation distance from the rotating shaft along the entire length of the radial recess. The diameter of this cylindrical overmolding is, for example, identical to that of the radial recess, except for an insertion clearance, which allows the radial connector's position within the radial recess to be controlled during assembly.

[0015] According to another optional and advantageous feature of the invention, the radial connector includes a sealing device arranged around the insulating body. This sealing device is, for example, an O-ring seal housed in a groove in the insulating body. It prevents the introduction of cooling oil into the radial recess of the rotating shaft when the rotor windings are oil-cooled.

[0016] According to another optional and advantageous feature of the invention, the electrical conductor of the radial connector has a tapped hole adapted to receive a thread of an electrical conductor of the axial connector. In order to allow such a screw connection between the electrical conductor of the radial connector and the electrical conductor of the axial connector, the insulating body of the radial connector has, for example, where it extends radially along this screw connection, a recess at the tapped hole to allow the thread of the axial connector to access this tapped hole.

[0017] According to another optional and advantageous feature of the invention, the axial connector comprises a body that electrically insulates the electrical conductor of the axial connector from the rotating shaft. This insulating body has, for example, the The shape of a cylindrical sleeve allows for a non-zero isolation distance from the rotating shaft along the entire length of the axial recess. The diameter of this cylindrical sleeve is, for example, identical to that of the radial recess, except for an insertion clearance, which allows for precise control of the axial connector's position within the axial recess during its mounting on the rotating shaft.

[0018] According to another optional and advantageous feature of the invention, the electrical conductor of the axial connector comprises a threaded end adapted to be screwed into the tapped hole of the electrical conductor of the radial connector. The threaded end is, for example, a cylindrical portion of the electrical conductor of the axial connector, the surface of which includes the thread adapted to allow it to be screwed into the tapped hole.

[0019] Preferably, to facilitate the attachment of the axial connector to the radial connector, the axial connector has a recess adapted to receive a tool for attaching the axial connector to the radial connector. The electrical conductor of the axial connector is, for example, formed of several cylindrical portions, one of which, with a larger diameter, has the recess on its free axial end surface, the thread being formed on a cylindrical portion with a smaller diameter. Furthermore, when the insulating body of the axial connector is a cylindrical sleeve, the electrical conductor of the axial connector is, for example, free to rotate within this cylindrical sleeve, which encloses the cylindrical portion with the larger diameter of the electrical conductor of the axial connector.

[0020] In one embodiment of the invention, the rotor according to the invention comprises a locking device equipped with an angular positioning device for an electrical lug projecting from the radial connector, the angular positioning device being capable of moving the electrical lug from an intermediate position to a final position. In this embodiment, the electrical lug into which the winding end is crimped or welded comprises a slide whose sliding axis can assume several angular positions relative to a longitudinal axis of the radial recess in which the radial connector is inserted, this longitudinal axis being radial with respect to the axis of rotation of the rotating shaft. This slide is itself arranged at the end of a portion of the electrical conductor of the radial connector, this portion projecting from the insulating body of the radial connector and possibly having a bent shape.Here, the intermediate or final position of the electrical lug, formed by the slide and this portion of electrical conductor, therefore refers to angular positions of the sliding axis and / or the bend formed by the portion of electrical conductor, relative to the longitudinal axis of the radial recess in which the radial connector is located. The sliding axis and / or the bend can indeed move angularly around this longitudinal axis, in a plane orthogonal to this longitudinal axis.

[0021] The locking device preferably acts on all the electrical terminals of the rotor. In particular, in the intermediate position, it keeps the sliding edges of the electrical terminals axially away from the rotor windings, thus facilitating the crimping and / or soldering of the winding ends to the electrical terminals, a process that would otherwise require a bulky tool. The locking device also holds the electrical terminals in their final position once the wires forming the winding ends have been crimped and / or soldered, these wires being under tension relative to their state in the intermediate position of the electrical terminals. The locking device therefore allows, through this wire tension, control of the insulation distances between the different rotor components.

[0022] The locking device is for example a collar clamping a cylindrical portion of the rotating shaft and being able to take several positions on the rotating shaft in the axial direction, depending on the intermediate or final position in which the electrical terminals are located.

[0023] The radial recess is for example made in a cylindrical portion of the rotating shaft, the locking device being able to be shrink-fitted onto the cylindrical portion of the rotating shaft.

[0024] The insulating body of the radial connector includes, for example, a collar from which the electrical lug protrudes, the collar having a locking stop and a rotation cam for the radial connector, suitable for cooperating with the locking device.

[0025] The angular positioning device includes, for example, a notch suitable for receiving the collar, the notch having a stop suitable for maintaining the rotation cam in the intermediate position, and a base provided with a shape complementary to the locking stop.

[0026] The locking device preferably comprises as many notches as there are radial connectors on the rotating shaft, each notch having a flange as mentioned above and positioned in radial recesses on the cylindrical portion of the rotating shaft. Preferably, each radial recess comprising a radial connector according to the invention is shaped in a similar manner.

[0027] Thus, during the shrink-fitting of the locking device onto the cylindrical portion of the rotating shaft, with the slot openings aligned with the flanges, the notch stops initially lock the flange rotation cams in the intermediate position, allowing the crimping and / or soldering of the winding end wires into the electrical terminals. Then, as the bottoms of the slots are brought towards the flanges by the shrink-fitting of the locking device, the rotation cams rotate the radial connectors until the flange locking stops are locked against the bottoms of the slots, the electrical terminals then being in their final position.

[0028] In order to radially lock the radial connector in the radial recess in the final position, the radial recess includes, for example, a counterbore suitable for receiving the collar, and the collar includes a ring positioned radially between a bottom of the counterbore and the locking device in the final position.

[0029] The ring is for example formed in the collar by flats in the upper part of the collar, the flats partly delimiting the rotation cam and the locking stop.

[0030] Furthermore, when the cylindrical portion of the rotating shaft onto which the locking device is shrink-fitted corresponds to a bearing of the rotating shaft, extending a flat surface of another cylindrical portion of larger diameter of the rotating shaft, the locking device preferably comes to rest against this flat surface in its final position. Thus, the position of the locking device is controlled relative to the radial connectors.

[0031] The invention also relates to a method for electrically connecting the winding ends of a rotor according to the invention to a rotor excitation system, comprising the following steps: - Insertion of the radial connector into the radial recess, - insertion of the locking device onto one end of the cylindrical portion of the rotating shaft, - intermediate positioning of the electrical lug by locking the rotation cam of the radial connector collar in the stop provided in the notch of the locking device,

[0032] - crimping one end of the winding into the electrical terminal,

[0033] - locking of the locking device relative to the rotating shaft, resulting rotating the electrical lug to its final position in which the locking stop of the radial connector collar is fitted into the complementary shape of the bottom of the locking device notch, and in which the tapped hole is positioned angularly opposite the axial recess, and - fixing the axial connector to the radial connector.

[0034] The connection method according to the invention also includes, of course, a step of connecting the axial connector to an electrical connection system present on one end of the rotating shaft, to the rotor excitation system, this electrical connection system being able to take various forms depending on the excitation system chosen.

[0035] The invention also relates to an electrical machine comprising a rotor according to the invention.

[0036] The connection method according to the invention and the electrical machine according to the invention have advantages similar to those of the rotor according to the invention.

[0037] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given by reference to the accompanying schematic drawings on the other hand, in which:

[0038] [Fig-1] represents in perspective a face of a wound rotor according to the invention, in an embodiment of the invention, the electrical lugs in which the winding wires of the rotor are crimped being in a locked position called final,

[0039] [Fig.2] represents in perspective a bare end of a rotating shaft of the wound rotor of the [Fig.1],

[0040] [Fig.3] is a front view of the stripped end of [Fig.2],

[0041] [Fig.4] is an axial cross-sectional view of the stripped end of [Fig.2],

[0042] [Fig. 5] is a perspective view of a radial connector of a device electrical connection of the wound rotor of the [Fig.l],

[0043] [Fig.6] is another perspective view of the radial connector of [Fig.5],

[0044] [Fig.7] is a cross-sectional view of an axial connector of a connection device electrical winding of the rotor of [Fig.1], fixed to the radial connector of [Fig.5],

[0045] [Fig.8] is a perspective view of several axial connectors identical to those of [Fig.7], connected by an insulating stop,

[0046] [Fig.9] is another perspective view of the axial connectors of [Fig.8],

[0047] [Fig. 10] is an axial cross-sectional view of an end portion of the wound rotor of [Fig. 1],

[0048] [Fig. 11] is a cross-sectional view of the axial connector assembly of [Fig. 7] and radial connector of [Fig. 5], fixed to each other,

[0049] [Fig. 12] is a perspective view of a locking device for the electrical terminals of the wound rotor of the [Fig. 1],

[0050] [Fig. 13] is a top view of the locking device in which the electrical lugs are in the locked position and connected via radial connectors to which they belong, to the axial connectors of [Fig. 8], the rotating shaft not being shown,

[0051] [Fig. 14] is a partial perspective view of the locking device assembly, radial connectors and axial connectors in the locked position of [Fig. 13],

[0052] [Fig. 15] is another partial perspective view of the whole of [Fig. 13],

[0053] [Fig.16] is a partial front view of the entire [Fig.13],

[0054] [Fig. 17] is an axial cross-sectional view of an end portion of the wound rotor of the [Fig. 1], in an intermediate position of the rotor's electrical terminals, these being unlocked in this intermediate position, the winding ends not yet being crimped and / or soldered into the electrical terminals,

[0055] [Fig.18] is a perspective view of one face of the rotor of [Fig.1] in this intermediate position of the electrical terminals,

[0056] [Fig. 19] is a top view of the locking device of [Fig. 12], in which the electrical lugs are in an intermediate position and not yet connected via radial connectors to the axial connectors of [Fig. 8], the rotating shaft not being shown,

[0057] [Fig.20] is a perspective view of the entire locking device, radial connectors and axial connectors in intermediate position of [Fig. 19],

[0058] [Fig.21] is a cross-sectional view of the whole of [Fig.20],

[0059] [Fig.22] is a partial perspective view of the whole of [Fig.20],

[0060] [Fig.23] is a partial front view of the entire [Fig.20], and

[0061] [Fig. 24] represents steps in a method of electrically connecting the ends of rotor winding of the [Fig.1], to a rotor excitation system.

[0062] According to an embodiment of the invention shown [Fig. 1], a rotor 1 for an electric machine according to the invention comprises a rotating shaft 100, onto which is shrink-fitted a stack of laminations 300 (visible [Fig. 10]) forming rotor teeth. On the axial ends of these teeth, winding supports 400 (visible [Fig. 10]) made of insulating material are positioned so as to each receive a winding for one of the rotor teeth. The rotor body thus comprises a set of windings 200, the ends 201 of which must be connected to a rotor excitation system.

[0063] A metal ring 800 also allows the coil heads of the rotor 1 to be held in place and the rotor 1 to be balanced. The latter must in fact have a uniformly distributed mass when it rotates around an axis of rotation X, parallel to the axial direction.

[0064] In order to connect the winding ends 201 to the excitation system of the rotor 1, electrical terminals 501 are used in this embodiment of the invention, in which the winding ends 201, here two copper wire ends, are crimped or soldered using a large crimping tool. Electrical connection devices are also used, each comprising a radial connector 500 (shown in [Fig. 5]) and an axial connector 700. The rotor 1 is thus equipped with two electrical connection devices, each connecting an electrical terminal 501 to an end surface of the rotating shaft 100 on which an electrical connection system to the excitation system of the rotor 1 is arranged, for example, slip rings.

[0065] We now describe, in relation to figures 2 to 4, the structure of the end of the rotating shaft 100 in which each of the radial connectors 500 and axial connectors 700 are arranged.

[0066] The end of the rotating shaft 100 has a first bearing 108 forming a shoulder of a cylindrical structure of the rotating shaft 100 carrying the body of the rotor 1, this first bearing 108 having two radial recesses 104 arranged at 180° to each other on this first bearing 108, and each intended to receive a radial connector 500. Each radial recess 104 has a counterbore 103 used to receive a collar 510 (referenced [Fig.5]) of a radial connector 500.

[0067] The cylindrical structure of the rotating shaft 100 carrying the rotor body 1 is connected to the first bearing 108 by a flat surface 107, and the first bearing 108 is connected to a second bearing 102 of smaller diameter by another flat surface 109. Finally, a last, unreferenced bearing forms a shoulder in the second bearing 102 and adjoins an axial end surface 106 of the rotating shaft 100, shaped like a ring, in which two axial recesses 105 are machined, arranged at 180° to each other on this ring shape. Each axial recess 105 is designed to receive an axial connector 700. A central recess 101 in the middle of the axial end surface 106 allows the insertion of a centering tool used during the assembly of the rotor 1.

[0068] When the rotating shaft 100 is cut along the plane AA shown in [Fig.3], this plane passing through the axis of rotation X and through a central axis of each axial recess 105, we obtain the cross-sectional view of [Fig.4], on which we can see that each axial recess 105 intersects a radial recess 104. These recesses are, for example, made by cylindrical holes in the rotating shaft 100. Each radial recess 104 therefore has a radially arranged axis of symmetry and each axial recess 105 has an axially arranged axis of symmetry.

[0069] This arrangement allows each radial connector 500, inserted into a radial recess 104, to be electrically connected to an axial connector 700, inserted into an axial recess 105, at the intersection of these recesses. This avoids altering the surface of a bearing on the rotating shaft, for example, the second bearing 102, on which a bearing fixed by its outer ring to a stationary part of the electrical machine will be positioned.

[0070] Alternatively, the end of the rotating shaft has more or fewer bearings compared to this embodiment, the radial recesses being arranged in any of these bearings provided that a cylindrical surface remains intact for the positioning of a bearing between the radial recesses and the axial end surface of the rotating shaft.

[0071] We now describe, in relation to figures 5 and 6, one of the radial connectors 500, the two radial connectors 500 being identical.

[0072] The radial connector 500 comprises an insulating body 506, for example made of glass fiber reinforced polyamide, this insulating body 506 being traversed lengthwise by an electrical conductor 5017 (referenced [Fig. 10]), for example made of copper, a portion of which protrudes from the insulating body, forming the electrical lug 501. The conductor The electrical conductor 5017 has a threaded hole 507 allowing a screw connection with an axial connector 700. For this purpose, the insulating body 506 has a lateral recess 508 leaving a portion of the electrical conductor 5017 exposed, which includes the threaded hole 507, and forms a receiving opening for a thread of the axial connector 700. The lateral recess 508 has a diameter corresponding, within an insertion clearance, to that of an insulating body 701 (referenced [Fig.7]) of an axial connector 700 so that the electrical connection between the radial connector 500 and the axial connector 700 is protected by their respective insulating bodies 506 and 701, the insulating body 701 of the axial connector 700 being partially inserted into the lateral recess 508.

[0073] The insulating body 506 is overmolded on a portion of the electrical conductor 5017 intended to be inserted into a radial recess 104, in order to electrically insulate this portion of the electrical conductor 5017 from the rotating shaft 100, made of steel.

[0074] The insulating body 506 has a collar 510 intended to bear against the counterbore 103 of the radial recess 104. Between the collar 510 and the lateral recess 508, a circular groove is arranged on the insulating body 506. This circular groove receives an O-ring seal 504 which prevents cooling oil spraying the windings 200 from going towards the bottom of the radial recess 104.

[0075] The collar 510 has several flats forming a ring 505 in the lower part of the collar 510, this ring 505 having a lower surface 509 bearing on the counterbore 103. One of the flats forms a locking stop 502 of the radial connector 500, and the other partially delimits a rotation cam 503 projecting radially, with respect to a longitudinal axis of the radial connector 500, from the collar 510. The longitudinal axis of the radial connector 500 coincides with the axis of symmetry of the radial recess 104 in which it is inserted.

[0076] The locking stop 502 forms a flat surface orthogonal to the central axis of the tapped hole 507. The rotation cam 503 of the radial connector 500 is arranged laterally to the locking stop 502 so as to protrude from the collar 510 on the side opposite the locking stop 502. The respective functions of the locking stop 502 and the rotation cam 503 will be explained later.

[0077] The insulating body 506 also includes a half-cylinder 511 mounted above the collar 510 so as to overmold one face of a bend formed by the electrical terminal 501. The terminal has a slide at its free end allowing a wire to be inserted into the slide for crimping and / or soldering. Since the electrical terminal 501 forms a bend relative to the rest of the electrical conductor 5017 of the radial connector 500, it can assume several angular positions relative to the longitudinal axis of the radial connector 500.

[0078] In particular, when the slide of the electrical terminal 501 is away from the rotor body 1, it is in an intermediate position allowing a large crimping tool to be brought into the slide for crimping and / or soldering a winding end 201, the slide being axially positioned at the second bearing 102. Conversely, when the slide is close to the rotor body 1, the electrical terminal 501 is generally parallel to the flat surfaces 107, 109 of the rotating shaft, in a so-called final position, which is not suitable for soldering or crimping the winding end 201 into the slide. The slide of the electrical terminal 501 is then axially positioned at the first bearing 108.

[0079] For example, in the intermediate position, the electrical lug 501 forms an angle of approximately 68° with the flat surfaces 107, 109 of the rotating shaft 100, in a plane orthogonal to the axis of symmetry of the radial recess 104 in which the radial connector 500 is inserted.

[0080] We now describe, in relation to figures 7 to 9, one of the two axial connectors 700, the two axial connectors 700 being identical.

[0081] The axial connector 700 comprises an electrical conductor 704, for example made of copper, formed of several cylindrical portions. The cylindrical portion with the largest diameter of the electrical conductor 704 is contained within a sheath-shaped insulating body 701, this insulating body being, for example, made of glass fiber-reinforced polyamide.

[0082] The electrical conductor 704 can rotate within the insulating body 701, which is integral with a ring 702 also made of insulating material, for example, formed from the same material as the insulating bodies of the axial connectors 700. The ring 702 comes to rest against the axial end surface 106 of the rotating shaft 100 when the axial connectors 700 are fixed to the radial connectors 500. The ring 702 leaves in its center a passage 703 for a centering tool that comes into the central recess 101 of the rotating shaft 100.

[0083] The sleeves forming the insulating bodies 701 are open at the surface of the ring 702, so as to allow the insertion of a tool into each sleeve, the tool having an end with a shape complementary to an indentation 708 formed on a surface of the electrical conductor 704 opposite the opening of the sleeve. This indentation allows the electrical conductor 704 to be moved relative to the insulating body 701, in particular to be rotated within the insulating body 701 and thus within the axial recess 105.

[0084] Alternatively, the insulating bodies 701 are integral with the electrical conductors 704, for example molded onto the electrical conductors 704, and are not connected by an insulating ring.

[0085] The electrical conductor 704 has, opposite the recess 708, a diameter reduction forming a bearing whose surface has a thread 707, the bearing corresponding to a threaded end part 706 of the electrical conductor 704, extended by a smaller diameter end piece 705, facilitating the positioning of the threaded end part 706 against the tapped hole 507 of a radial connector 500 to which it is screwed.

[0086] In [Fig.7] the axial connector 700 is shown screwed into the tapped hole 507 of a radial connector 500, in a final position of the electrical terminals 501 of the rotor 1.

[0087] Indeed, in this final position represented in figures 10 and 11, the lateral recesses 508 of the radial connectors 500 are turned to face the openings of the axial recesses 105 in the rotating shaft 100, which allows the axial connectors 700 to be screwed into the threaded holes 507 positioned in these lateral recesses 508.

[0088] A locking device 600 secures the electrical terminals 501 in this final position, allowing them to be tightened. Figure 11 more clearly shows the locking device 600 bearing against the locking stop 502 of a radial connector 500, thus preventing it from rotating about the longitudinal axis of the radial connector 500.

[0089] As seen in [Fig. 12], the locking device 600 has the form of a ring whose internal cylindrical surface is a shrink-fit surface 601 of the locking device 600 on the first bearing 108 of the rotating shaft 100, and whose external cylindrical surface is a winding surface 604 of the winding ends before reaching the slides of the electrical terminals 501. The locking device 600 is made of insulating material, for example of glass fiber-reinforced polyamide.

[0090] The locking device 600 is therefore a fret having two diametrically opposed notches 610 intended to receive each a collar 510 of a radial connector 500 inserted in a radial recess 104. The bottom 603 of each notch 610 is of complementary shape to the locking stop 502 of a collar 510 of radial connector 500.

[0091] Each notch 610 has a lateral surface forming a flap side 605 of the collar 510 and a stop 602 in the form of a lateral notch in the flared opening of the notch 610. The notches 610 form an angular positioning device for the radial connectors 500 relative to their longitudinal axis in their respective radial recesses 104.

[0092] As seen in Figures 13 to 16, when the radial connectors 500 are in their final position locked by the locking device 600, their locking stops 502 are in contact with the bottoms of the notches 603, locking their electrical lugs 501 in a position orthogonal to the axis of rotation X of the rotating shaft and parallel to the flat surfaces 107, 109 of the rotating shaft 100, and positioning their lateral recesses 508 opposite the openings of the axial recesses 105.

[0093] Furthermore, in this final position, the rotation cams 503 of the radial connectors are arranged against the flap sides 605 of the notches 610. In addition, in this final position, the two electrical terminals 501 point in opposite directions parallel to the flat surfaces 107, 109 of the rotating shaft 100, in order to ensure dynamic balancing of the rotating rotor 1. Finally, in this final position, the locking device 600 is fully shrink-fitted onto the first bearing 108, that is, it abuts against the flat surface 107 of the rotating shaft 100, except, of course, at the radial connectors 500, which are placed in the notches 610 of the locking device 600.

[0094] Figures 17 to 23 show the radial connectors 500 in an intermediate position, i.e. an unlocked position in which the ends 201 of the windings can be easily crimped and / or soldered into the electrical lugs 501. In this intermediate position, the locking device 600 is not fully shrink-fitted onto the first bearing 108, being axially separated by one centimeter from the flat surface 107 formed by the first bearing 108 on the rotating shaft 100.

[0095] In this intermediate position, the radial connectors 500 can therefore rotate in their radial recesses 104, their flanges 510 being able to rotate until the rotation cam 503 of each flange 510 comes to a stop against the stop 602 of the corresponding notch 610. In this intermediate position, the rotation cams 503 of the flanges 510 are held against the stops 602 of the notches, the electrical terminals 510 thus forming an angle of 68° with the flat surface 107 of the rotating shaft 100, which makes it possible to bring a crimping or soldering tool close to the electrical terminals 501, and to crimp and / or solder the ends 201 of the windings in the slots of the electrical terminals 501, without damaging the other parts of the rotor windings.

[0096] Moreover, in this intermediate position, as seen [Fig.21], the lateral recesses 508 of the radial connectors are not located opposite the openings of the axial recesses 105 and therefore do not allow the axial connectors 700 to be screwed onto the radial connectors 500.

[0097] We now describe in relation to [Fig.24], an electrical connection method 900 according to the invention, of the ends 201 of the windings of the rotor 1, to an excitation system of the rotor 1.

[0098] A first step 910 of the process is the insertion of the radial connectors 500 into the radial recesses 104, until the rings 505 of the flanges 510 of the radial connectors 500 come into contact with the counterbores 103 provided in the radial recesses 104. The flanges 510 are further positioned angularly, with respect to the longitudinal axes of their respective radial connectors 500, so that their rotation cams 503 are turned towards the body of the rotor 1.

[0099] A second step 920 of the process is shrink-fitting the locking device 600 onto a portion of the first bearing 108 until the ring formed by the locking device 600 is about one centimeter from the flat surface 107 of the rotating shaft 100.

[0100] A third step 930 of the process is the intermediate positioning of the electrical lugs 501 by bringing the rotation cams 503 of the flanges 510 of the radial connectors 500 against the stops 602 of the notches 610 of the locking device 600. The electrical lugs 501 then form an angle of approximately 68° with the flat surface 107 of the rotating shaft, thus moving the slides of the electrical lugs 501 away from the body of the rotor 1.

[0101] A fourth step 940 of the process is the winding of the wire portions having the winding ends 201 of the rotor 1, around the insulating ring formed by the locking device 600, until the winding ends 201 reach the slides of the electrical terminals 501. The winding ends 201 are then inserted into the slides and then crimped and / or welded into the slides of the electrical terminals 501.

[0102] In a fifth step 950 of the process, the shrink-fitting of the locking device 600 onto the first bearing 108 of the rotating shaft 100 is continued, causing the rotating cams 503 to rotate until the locking stops 502 come into contact with the bottoms 603 of the notches 610 of the locking device 600. The electrical terminals 501 are then in their final position, the locking device 600 comes into contact with the flat surface 107 of the rotating shaft, the lateral recesses 508 of the radial connectors 500 are oriented towards the openings of the axial recesses 105, and the rings 505 of the flanges 510 are positioned radially between the counterbores 103 and the locking device 600, which prevents the radial connectors 500 from being removed. This fifth step 950 also allows to tighten the wires forming the ends 201 of the rotor winding.This tension on the wires helps to keep them in position despite the centrifugal force to which they are subjected during the rotation of rotor 1, and thus to prolong their lifespan, as flexible wires can move and be damaged during this rotation of rotor 1.

[0103] A sixth step 960 of the process is screwing the threads of the axial connectors 700 into the tapped holes 507 of the radial connectors 500, through their lateral recesses 508, which have a diameter suitable for receiving the insulating bodies 701 of the axial connectors 700. To do this, the axial connectors 700 are inserted into the axial recesses 105, then a tool is inserted into the recesses 708 of the axial connectors 700, and the axial connectors 700 are pushed with this tool until the threaded end portions 706 of the electrical conductors 704 reach the tapped holes 507. Then, the threads 707 are screwed in using this tool. electrical conductors 704 in the tapped holes 507. At the end of screwing, the insulating ring 702 connecting the axial connectors 700 comes to rest against the axial end surface 106 of the rotating shaft 100.

[0104] A seventh step 970 of the method is the electrical connection of the axial connectors to an electrical connection system at the end of the rotating shaft 100, for example copper bushings, enabling connection to a carbon brush-based rotor excitation system. Alternatively, another electrical connection system is used at the end of the rotating shaft 100, for example using capacitive coupling with a corresponding rotor excitation system 1.

[0105] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of the different embodiments of the invention envisaged in this application can be combined to carry out the invention, provided that these embodiments are not incompatible with each other.

Claims

Demands

1. Rotor (1) for an electric machine, comprising a rotating shaft (100), a rotor body comprising at least one winding (200), and electrical connection devices for electrically connecting the ends (201) of the rotor winding (1) to a rotor excitation system (1), at least one of the electrical connection devices comprising a radial connector (500) disposed in a radial recess (104) of the rotating shaft (100) and an axial connector (700) disposed in an axial recess (105) of the rotating shaft (100), the rotor (1) further comprising means for fixing the radial connector (500) to the axial connector (700), the rotor being characterized in that it comprises a locking device (600) provided with a device for angularly positioning an electrical lug (501) projecting from the radial connector (500),the angular positioning device being capable of moving the electrical terminal (501) from an intermediate position to a final position.

2. Rotor (1) for electric machine according to claim 1, wherein the radial connector (500) comprises an electrical conductor (5017) and an insulating body (506) electrically insulating the electrical conductor (5017) with respect to the rotating shaft (100).

3. Rotor (1) for electric machine according to claim 2, wherein the radial connector (500) has a sealing device (504) arranged around the insulating body (506).

4. Rotor (1) for an electric machine according to claim 2 or 3, wherein the electrical conductor (5017) of the radial connector (500) has a tapped hole (507) suitable for receiving a thread (707) of an electrical conductor (704) of the axial connector (700).

5. Rotor (1) for an electric machine according to any one of claims 1 to 4, wherein the axial connector (700) comprises a body (701) electrically insulating the electrical conductor (704) of the axial connector (700) with respect to the rotating shaft (100).

6. Rotor (1) for electric machine according to claims 4 and 5, wherein the electrical conductor (704) of the axial connector (700) has a threaded end (706), suitable for being screwed into the tapped hole (507) of the electrical conductor (5017) of the radial connector (500).

7. Rotor (1) for electric machine according to claim 6, wherein the axial connector (700) has a recess (708) suitable for receiving a tool for fixing the axial connector (700) to the radial connector (500).

8. Rotor (1) for electric machine according to any one of claims 1 to 7, wherein the radial recess (104) is made in a cylindrical portion (108) of the rotating shaft (100), the locking device (600) being able to be shrink-fitted onto the cylindrical portion (108) of the rotating shaft (100).

9. Rotor (1) for an electric machine according to claim 8 taken in combination with claim 2, wherein the insulating body (506) of the radial connector (500) has a flange (510) from which the electrical lug (501) protrudes, the flange (510) having a locking stop (502) and a rotation cam (503) of the radial connector (500), adapted to cooperate with the locking device (600).

10. Rotor (1) for electric machine according to claim 9, in which the angular positioning device has a notch (610) adapted to receive the collar (510), the notch (610) having a stop (602) adapted to maintain the rotation cam (503) in the intermediate position, and a base (603) provided with a form complementary to the locking stop (502).

11. Rotor (1) for electric machine according to claim 10, wherein the radial recess (104) has a counterbore (103) adapted to receive the flange (510), and wherein the flange (510) has a ring (505) positioned radially between a bottom of the counterbore (103) and the locking device (600) in the final position.

12. A method for electrically connecting (900) the winding ends (201) of a rotor (1) according to any one of claims 10 or 11 combined with claim 4 to a rotor excitation system (1), comprising the steps of: - inserting (910) the radial connector (500) into the radial recess (104), - introducing (920) the locking device (600) onto one end of the cylindrical portion (108) of the rotating shaft (100), - intermediately positioning (930) the electrical terminal (501) by locking the rotation cam (503) of the flange (510) of the radial connector (500) in the stop (602) formed in the notch (610) of the locking device (600), - crimping and / or soldering (940) of one end (201) of the winding into the electrical lug (501), - locking (950) of the locking device (600) relative to the rotating shaft (100), rotating the electrical terminal (501) to its final position in which the locking stop (502) of the flange (510) of the radial connector (500) is fitted into the complementary shape of the bottom (603) of the notch (610) of the locking device (600), and in which the tapped hole (507) is positioned angularly opposite the axial recess (105), and - fixing (960) of the axial connector (700) to the radial connector (500).

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