FR3085808A1 - ROTATING ELECTRICAL MACHINE PROVIDED WITH AN INTERCONNECTOR WITH PARALLELS - Google Patents

Abstract

The invention relates mainly to an interconnector (30) for the interconnection between two conductors of a stator winding (24) of an electric machine, extending over an angular sector (α) around an axis X, the interconnector (30) comprising at least two electrically conductive tabs (31, 32) angularly offset, each electrically conductive tab having a radial end surface (300) defining a connection surface for a portion of conductor of the winding (240) of an electric machine , from one tab to the other, these radial end surfaces (300) being parallel.

Description

ROTATING ELECTRIC MACHINE PROVIDED WITH AN INTERCONNECTOR WITH PARALLELS.

The invention relates to an interconnector with connection tabs for the portion of the winding conductor which are parallel to each other.

In a manner known per se, rotary electrical machines comprise a stator and a rotor secured to a shaft. The rotor can be integral with a driving and / or driven shaft and can belong to a rotating electrical machine in the form of an alternator, an electric motor, or a reversible machine capable of operating in both modes.

Furthermore, the stator is mounted in a casing configured to carry the shaft in rotation, for example by means of bearings. The stator comprises a body constituted by a stack of thin sheets forming a crown-shaped cylinder head, the inner face of which is provided with notches open towards the inside to receive a winding.

In a wavy type winding, the phase windings are each formed from at least one winding conductor, such as a continuous wire, covered with an insulating layer, in particular an enamel layer. Alternatively, the winding is obtained from winding conductors in the form of pins electrically connected to each other, for example by welding.

Parts of the winding conductor must be electrically connected via an interconnector to obtain a desired electrical coupling of the machine, for example in a triangle or a star. For this purpose, electrical connections between these portions of winding conductors and the legs of the interconnector will be necessary.

The use of such interconnectors known from document US 2014/0183993 notably requires bending certain portions of the winding conductors to bring them close to the lug to be connected, a different curvature being able to be given to the portion of the winding conductor in function the position of the tab relative to said end. Furthermore, the connection of each portion of conductor to each tab can be quite complex, requiring numerous readjustment steps depending on the orientation of the tab to be fixed.

The present invention aims to effectively remedy these drawbacks by proposing an interconnector for the interconnection between two conductors of a stator winding of an electrical machine, extending over an angular sector around an axis, the interconnector comprising at least two electrically conductive tabs angularly offset, each electrically conductive tab having a radial end surface defining a connection surface for a conductor portion of the winding of an electric machine, from one tab to the other, these radial end surfaces being parallel .

All the connection surfaces being parallel in such an interconnector according to the invention, this makes it easier to approach the portions of conductors for connection in a common direction. Furthermore, this simplifies the process of fixing the legs by minimizing, for example, the displacement of a possible laser head in the case of welding of the successive legs on the corresponding conductor portions by such a head.

According to one embodiment, each radial end surface extends substantially along the axis. This simplifies the connection between the coil and the interconnector by adapting the orientation of the legs of the interconnector to the coil portions to be connected.

In one embodiment, the interconnector also includes clips for holding other winding conductors adapted to direct a portion of other winding conductor towards control electronics. This makes it easier to hold conductors going to electronics while reducing the impact of vibrations on these conductors and therefore reducing the risk of breakage.

According to one embodiment, the interconnector also comprises at least one conductive body, the tabs being connected together by the conductive body. This interconnector structure is simple to make and compact.

According to one embodiment, the interconnector comprises two conductive bodies positioned one above the other along the axis, the two conductive bodies being non-electrically connected to each other, each conductive body connecting between they have several legs. This allows two separate phase systems to be connected, for example two three phase systems. The conductive elements of the interconnector may be the same or different.

Alternatively, the interconnector comprises two conductive bodies positioned one next to the other around the axis, the two conductive elements being non-electrically connected to each other, each conductive body connecting together several tabs. This allows two separate phase systems to be connected, for example two three phase systems. The conductive elements of the interconnector may be the same or different.

According to one embodiment, the free surfaces of the legs are substantially contained in the same plane. This simplifies the welding step without having to change the height of the welding device, for example the laser.

The invention also relates to a machine comprising a stator winding extending in a circumferential direction around the axis, an interconnector as previously described. According to the invention, the legs of the interconnector are arranged along the circumferential direction of the stator winding. This minimizes the movements of the welding device and therefore simplifies the winding connection process.

According to one embodiment, the portion of the winding conductor is fixed to the connection surface of the tab by laser welding.

According to one embodiment, each tab of the interconnector is connected to a portion of the winding conductor belonging to a separate phase of the winding. This makes it possible to achieve the neutral point or the triangle coupling of said stator winding.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

Figure 1 is a partial sectional view of a rotating electrical machine for carrying an interconnector according to the present invention;

Figure 2 is a perspective view of the stator carrying the interconnector according to the invention ensuring the coupling of the winding conductor portions;

Figure 3a shows a perspective view of the interconnector according to the present invention;

Figure 3b is a top view of the interconnector according to the present invention;

Figure 4 is a perspective view of the conductive elements of the interconnector according to the present invention excluding overmolding;

FIG. 5 illustrates the fixing of the tabs to the conductor portions by laser welding.

Identical, similar, or analogous items retain the same reference from one figure to another.

FIG. 1 represents a compact and polyphase rotary electrical machine 10, in particular for a motor vehicle. This rotating electrical machine converts mechanical energy into electrical energy, in alternator mode, and can operate in motor mode to transform electrical energy into mechanical energy. This rotary electric machine is, for example, an alternator or a reversible machine.

The rotary electrical machine comprises a casing 11. Inside this casing, it further comprises the shaft 12, the rotor 13 integral in rotation with the shaft and the stator 14 surrounding the rotor. The rotational movement of the rotor 12 takes place around an axis X, which is the axis of the machine. In the following description, the radial, ortho-radial and axial orientations are to be considered with respect to this axis X. In the following description, the rear part is the part of the machine comprising the electronics and the front part is the part of the machine on the pulley side.

In this example, the casing 11 comprises a front bearing 15 and a rear bearing 16 which are assembled together. These bearings are hollow in shape and each carry a respective ball bearing centrally for the rotational mounting of the shaft 12.

A pulley 17 is attached to a front end of the shaft 12, at the front bearing. This pulley 17 transmits the rotational movement to the shaft.

The rear end of the shaft 12 carries a collector 18. A brush holder 21 supplies the rotor via the collector and is connected to a voltage regulator (not shown) included in a rectifier bridge.

The front bearing 15 and the rear bearing 16 may further include openings 27 substantially lateral for the passage of air in order to allow the cooling of the rotary electric machine by air circulation generated by the rotation of a front fan 28 on the front face of the rotor, that is to say at the level of the front bearing and a rear fan 19 on the rear face of the rotor, that is to say at the level of the rear bearing.

In this exemplary embodiment, the stator 14 comprises a body in the form of a packet of sheets 23 provided with notches, for example of the semi-closed or open type, equipped with insulating notches for mounting a stator winding. 24. The stator body has an annular cylindrical shape with an axis X. The winding 24 passes through the notches of the body and forms a front bun 25 and a rear bun 26 on either side of the stator body 14.

The winding extends in a circumferential direction around the X axis along the body of the stator.

The winding 24 also extends radially between an internal winding periphery closer to the axis X and an external winding periphery closer to the bearing.

In this example, the rotor 13 is a claw rotor comprising two pole wheels. When the rotor 13 is magnetized and becomes an inductor rotor with the formation of North-South magnetic poles, an alternating induced current is created in the coil 24 of the stator 14 induced by the rotation of the shaft 12.

A rectifier bridge formed by electronic power modules (not shown) then transforms this alternating induced current generated by the machine into a direct current, in particular to supply the loads and consumers of the on-board network of the motor vehicle as well as to recharge its battery. . These modules or other power modules can also be ordered to inject current into the different phases of the electric machine when the latter is operating in motor mode.

The stator winding 24 is composed of a plurality of conductors forming the phases. More precisely, each phase comprises a first end of electrical conductor 240 forming an electrical neutral point, a second end of electrical conductor 242 forming a connection point of a phase output, the phase connection terminals therefore being formed by two ends driver.

The second ends of conductor 242 are electrically connected to the electronic power modules.

In what follows, stator circumference will be understood to mean a curve among the curves matching the average position of the stator winding. A stator circumference will for example be given by a circle centered on the X axis and passing through the ends of the conductors.

In what follows, the term angular sector will be understood to mean the angle defined along the stator winding, from the center of the machine, around the axis X, in a plane orthogonal to the axis of the machine.

Advantageously, as illustrated in FIG. 2, the ends of the conductor 240, 242 are therefore on the same stator circumference and extend along an angular sector of the stator 14. The angular difference between the first ends of the phases 240 is constant along the angular sector in which the ends are situated, as shown in FIG. 2. In the same way the angular difference between the second ends of the phases 242 is constant along the angular sector in which they lie . The conductor ends each advantageously extend along the X axis of the machine.

In a first embodiment, the winding is a three-phase winding. The portions of winding conductors 240 to be interconnected are then the first ends of electrical conductor, to be connected to the neutral point electrically.

The first ends 240 connected to the neutral point are connected by means of an interconnector 30 visible in FIG. 2.

This interconnector 30 extends in the shape of an arc of a circle over an angular sector of angle a around the axis X above the front (or rear) chignon, that is to say in a plane orthogonal to the axis of the machine X. The interconnector 30 extends along a limited angular sector between 30 ° and 90 °. The interconnector 30 advantageously follows the curvature around the axis X of the front bun, in the form of an arc.

The interconnector 30 positioned substantially between the inner and outer peripheries of the winding, can notably protrude radially from the stator winding.

The interconnector 30 advantageously comprises three legs 31, 32, 33, electrically conductive, angularly offset. The legs 31, 32, 33 are distributed along the arc of the interconnector, advantageously following the curvature of the interconnector, as illustrated in FIG. 3a. The legs are advantageously angularly close, that is to say separated by a small circumferential distance which advantageously corresponds to the distance separating the first ends of the conductor.

Each tab of the interconnector positioned radially between the axis of the machine and the bearing advantageously extends along the axis X. The tabs of the interconnector advantageously extend on the same side of the stator winding 24 as the ends of the conductors 240, 242.

A conductive body 34 advantageously electrically connects the tabs together. The body 34 extends for example in an extension plane of the interconnector 30 and the lugs 31, 32, 33 extend from the body of the interconnector 34. The lugs extend for example in a first portion 341 contained in the plane of the body and then an adjacent portion 342 transverse to the previous portion and extending along the axis X, as illustrated in FIG. 4. The legs thus have a bent shape. A conductive element is thus formed by said body 34 and the tabs 31, 32, 33.

Each lug has a radial end surface 300 illustrated in FIG. 3a, advantageously carried by the lug portion extending along the axis X of the machine, that is to say the portion of the lug adjacent to the free end of the tab. The radial end surface 300 defines a connection surface for a first end of the conductor 240.

From one leg to the other, these radial end surfaces 300 are parallel, as illustrated in FIG. 3b.

Given the small angular sector of extension of the interconnector 30 less than 90 °, the radial end surfaces 300 will therefore be oriented substantially orthoradially.

The legs are for example of rectangular section in the plane transverse to their direction of extension, so that the radial end surface 300 is opposite to an opposite surface, the two surfaces being separated by the conductor, one of the surfaces being opposite the bearing and the opposite surface being opposite the axis X of the machine, the two surfaces being separated by a small thickness.

In a variant of the first embodiment, the stator 14 has a three-phase double winding. The interconnector 30 then comprises two conductive elements 35 and 35 ’. Each conductive element is formed of the conductive body 34, 34 ’electrically connecting three tabs 31, 32, 33 and 3T, 32’, 33 ’between them. The two conductive bodies 34, 34 ’are not electrically connected, each of the conductive elements making it possible to connect one of the two three-phase systems. All the radial end surfaces 300 of the legs are parallel for this interconnector, as illustrated in FIG. 4.

The legs of the two conductive elements 35 and 35 ’will advantageously be interposed, that is to say that two adjacent legs of the interconnector 30 in the circumferential direction will belong to two different conductive elements.

In order to establish the connections, the first three ends 240 of the first three-phase system are electrically connected to the first conductive element 35, and the other three first ends of the second three-phase system are electrically connected to the second conductive element 35 ’. As can be seen in Figure 4, the conductive bodies extend substantially parallel to each other thus forming a constant gap between the conductive bodies 34, 34 'substantially over the entire length over which extend the conductive elements, a layer of electrically insulating material being for example interposed between the two conductive elements.

As a variant, the conductive elements 35, 35 ’are partially overmolded by an insulating material, thus forming the interconnector. The insulating material may be a plastic material reinforced with fibers or even a resin.

As a variant, the two conducting bodies 34, 34 ′ extend one next to the other along the circumference of the winding.

Without necessary deviation of the wire, the first ends of the conductor 240 each exit parallel and opposite a connection surface 300 of a tab to be fixed and each is directly connected to the connection surface 300 of the opposite tab.

In a second embodiment not shown, the portions of winding conductors 240 to be interconnected are interconnection ends of the same phase of a winding to be brought back to the same potential, for example.

Whatever the embodiment, the interconnector 30 may include retaining clips 36 in particular for the second ends of the conductor 242 intended to be connected to the electronics, as explained above. Such clips 36 make it possible in particular to maintain these second ends of conductor 242 and to direct them towards the electronics. Such retaining clips 36 extend for example in the plane of the interconnector and are in the form of jaws. The clips 36 are advantageously made in one piece with the interconnector 30.

Each first end of the conductor 240 is advantageously fixed to the facing tab to which it must be connected, by laser welding, illustrated in FIG. 5. The welding is carried out at the free end surface of the tab 301, and an end surface to be welded 241 to the end of the conductor. These end surfaces 241 and 301 are advantageously substantially the same size, with a difference of the order of 20 percent.

In practice, the end of the conductor 240 will be cut beforehand, then a tool bends and maintains this end of the conductor to be welded resting on the support surface 300 of the tab.

The surfaces of the free ends 301 of the legs 31, 32, 33, 31 ', 32', 33 'will advantageously be substantially all contained in the same plane, for example perpendicular to the axis X, in order to simplify the welding process. .

The end surfaces to be welded 241 are then also advantageously contained in this same plane, which will be the welding plane.

The welding plane therefore comprising both the surfaces to be welded of the ends of conductors 241 and free ends 301 of the corresponding tabs, this makes it possible to simplify the sequence of welds by in particular not having to modify the height of the laser 38 for shooting.

The choice of two identical materials for the tab and the conductor portion 240 makes it possible to further improve the soldering, such as almost pure copper in particular.

The end of the conductor 240 to be welded will be stripped for example over a height along X of 4mm, advantageously 3mm, from the surface to be welded 241, and a length of lug of 4 mm along the axis X will advantageously exceed the plastic overmolding of the '' interconnector 30.

The conductor end 240 will thus advantageously be sufficiently stripped and the free end surface 301 of the tab sufficiently distant from the plastic of the interconnector 30 so that the heat generated by the laser shot near the welding point does not risk burn the conductor's enamel or the interconnector's plastic, which can generate gases and splashes of material. Such gases which can contaminate the weld and generate the appearance of bubbles inside and the projections of materials which can contaminate the weld in progress, the neighboring tabs, the stator and the tools are thus avoided as much as possible.

The axis of the laser 38 performing the weld is used perpendicular to the weld plane, therefore along the X axis here typically.

We will use a bi-spot laser (firing in two points and not in only one), allowing to fire simultaneously on the two surfaces to be welded 241 and 301. This will allow in particular to weld despite a slight axial offset between the tab and the end conductor 240.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention from which one would not depart by replacing the various elements with any other equivalent.

Furthermore, the various features, variants, and / or embodiments of the present invention can be combined with one another in various combinations, insofar as they are not incompatible or mutually exclusive of one another.

Claims (10)

1. Interconnector (30) for the interconnection between two conductors of a stator winding (24) of an electrical machine, extending over an angular sector (oc) around an axis X, the interconnector (30) comprising at at least two electrically conductive tabs (31, 32) angularly offset, each electrically conductive tab having a radial end surface (300) defining a connection surface for a portion of conductor of the winding (240) of an electric machine, of a tab to the other, these radial end surfaces (300) being parallel. 2. Interconnector according to the preceding claim in which each radial end surface (300) extends substantially along the axis X. 3. Interconnector according to any one of the preceding claims also comprising clips for holding other winding conductors (36) adapted to direct a portion of other winding conductor towards control electronics. 4. Interconnector according to one of the preceding claims also comprising at least one conductive body (34), the tabs (31, 32, 33) being connected to each other by the conductive body (34). 5. Interconnector according to claim 4 comprising two conductive bodies (34, 34 ') positioned one above the other along the X axis, the two conductive bodies (34, 34') being non-electrically connected to each other, each conductive body connecting several legs together. 6. Interconnector according to claim 4 comprising two conductive bodies (34, 34 ') positioned one next to the other around the axis X, the two conductive elements being not electrically connected to each other, each conductive body connecting several legs together. 7. Interconnector according to any one of the preceding claims, in which the free surfaces (301) of the legs are substantially contained in the same plane. 8. Machine including: a stator winding (24) extending in a circumferential direction around the axis X, an interconnector (30) according to any one of claims 1 to 7, in which the tabs (31, 32) of the interconnector ( 30) are arranged along the circumferential direction of the stator winding (24). 9. Machine according to claim 8, in which the portion of the winding conductor (240) is fixed to the connection surface (300) of the tab by laser welding. 10. Machine according to one of claims 8 to 9 wherein each tab (31,32) of the interconnector (30) is connected to a portion of the winding conductor (240) belonging to a separate phase of the winding.