FR3126567A1 - METHOD FOR WINDING A STATOR OF A ROTATING ELECTRIC MACHINE WITH MULTI-SLOTS PER POLE AND PER PHASE - Google Patents

Abstract

The invention relates to a method for winding a polyphase stator (10) with multiple slots per pole and per phase comprising in particular: - a step of winding at least a portion of at least a first turn (Sp1) of a continuous conductor (C1, C2, C3) following a pitch of basic notches (P_b), - a step of applying a special notch pitch (P_r) different from the basic notch pitch (P_b), - then a step of winding at least a portion of at least a second turn (Sp2) of said continuous conductor (C1, C2, C3) following the pitch of basic notches (P_b), - said at least one first turn (Sp1) and said at least one second turn (Sp2) of a given phase winding (PH1, PH2, PH3) being continuously connected to one another by said continuous conductor (C1, C2, C3). Figure 2

Description

METHOD FOR WINDING A STATOR OF A ROTATING ELECTRIC MACHINE WITH MULTI-SLOTS PER POLE AND PER PHASE

The present invention relates to a method for winding a stator of a rotating electrical machine with multiple slots per pole and per phase, as well as to the corresponding wound stator. The invention finds a particularly advantageous application for a stator of a rotating electrical machine such as for example an alternator, an alternator-starter, a reversible machine or an electric motor of a vehicle or a drone.

In a manner known per se, rotating electrical machines comprise a stator and a rotor secured to a shaft. The rotor may be integral with a driving and/or driven shaft. The electric machine comprises a casing carrying the stator. This casing is also configured to carry the shaft of the rotor in rotation, for example via bearings.

The stator comprises a body consisting of a stack of sheet metal sheets as well as a winding of the phases received in notches of the stator which are open radially. The phases are generally three in number for a three-phase machine or six for a six-phase machine.

In the stators of alternators of this type, the most commonly used types of windings are windings of the "wavy" type comprising a plurality of phase windings. Each phase winding comprises a spiral conductor, each turn of which forms undulations traversing the notches of the body. Thus, in each turn, the conductor has axial strands located inside the notches of the stator and connecting strands located alternately on each side of the stator interconnecting axial strands. The conductor may be formed from one or more electrically conductive wires. The set of connecting strands extending from one side of the stator forms a winding bun. The phase windings each have a phase input and a phase output corresponding respectively to a first and a second end of a phase winding. The phase inputs and outputs are intended to be interconnected to perform a coupling (delta, star, or hybrid of delta-star type or other) of the different phases of the electrical machine.

A winding method is known in which all of the phase windings are wound at the same time and in parallel in the corresponding notches of the body of the stator to obtain a six-phase winding. As illustrated by the , in order to transform a six-phase winding into a multi-slot three-phase winding per pole and per phase, it is necessary to make J1-J3 junctions between the phase windings to go from six phase windings PH1-PH6 to three phase windings. phase.

Such a transformation of a six-phase winding into a multi-slot three-phase winding per pole and per phase makes it possible to obtain a performance and cost compromise between a three-phase winding and a six-phase winding. Indeed, the winding obtained is more economical than a six-phase winding due to the reduction in the number of electronic components, while being more efficient than a three-phase winding.

In order to make the junctions between the windings, an interconnector INT is generally used providing the connections between the inputs and the outputs of the phases between them. However, such an interconnector induces an additional cost, additional assembly steps to connect the phase inputs and outputs to said interconnector, as well as an increase in the size at the level of a winding bun of the stator due to the presence of the interconnector.

The invention aims to effectively remedy the aforementioned drawbacks by proposing a method for winding a polyphase stator with multiple slots per pole and per phase, said stator comprising slots intended to receive conductors of a winding, said winding comprising a number N of phase windings, said method comprising at least the following steps to produce each phase winding:

- a first step of winding at least a portion of at least a first turn of a continuous conductor of a phase winding following a pitch of basic notches, so as to leave at least one free notch between two slots intended to be filled by two continuous conductors of two adjacent phase windings,

- a step of applying a special notch pitch different from the basic notch pitch, so that the continuous conductor of said phase winding is inserted inside a free notch adjacent to a notch in which is also inserted said continuous conductor of said phase winding,

- then a second step of winding at least a portion of at least a second turn of said continuous conductor following the pitch of basic notches,

- said at least one first turn and said at least one second turn of said phase winding being continuously connected together by said continuous conductor.

The invention thus makes it possible, by ensuring a continuous connection between the turns of a phase winding, to propose an economical solution compared to a similar winding where the connection between the turns is obtained by means of an interconnector. The invention also makes it possible to obtain a compact stator by avoiding the integration of an additional component close to a bun. The invention also has the advantage of reducing airflow and magnetic noise compared to a standard three-phase machine. The invention also makes it possible to attenuate certain harmonics of the rotating electrical machine.

The term “free notch” is understood to mean a notch which does not include a conductor during a given step of the winding process, it being understood that once the winding process is completed, all the notches include conductors.

“Continuously” means a connection made directly by the driver himself. No additional system such as an interconnector or a weld is necessary to make the electrical connection between the turns.

According to one implementation of the invention, the at least a portion of at least a first turn of a continuous conductor is wound in a first direction of winding and the at least a portion of at least a second turn of said conductor DC is wound in a second reverse winding direction to the first winding direction. This makes it possible to obtain buns that are less cumbersome, in particular in a radial direction by alternating the position of the connecting strands in the front bun or the back bun between the turns.

According to an implementation of the invention, to achieve each phase winding:

- the first winding step comprises the winding of an integer number M of turns of the continuous conductor to form a first coil, and

- the second winding step comprises the winding of an integer number M' of turns of said continuous conductor to form a second coil,

- the special notch pitch being applied between the first coil and the second coil of the phase winding,

- said first coil and said second coil of said phase winding being continuously connected together by said continuous conductor.

For example, M and M' are whole numbers strictly greater than 1.

Alternatively, each winding step includes the winding of a single turn.

According to one implementation of the invention, the phase windings are wound simultaneously or one after the other.

According to one implementation of the invention, the method comprises several steps of applying a special notch pitch and several winding steps following the basic notch pitch, each application step being preceded by a winding step and followed by another winding step, the turns of said phase winding obtained by the winding steps being continuously interconnected by said continuous conductor.

According to one implementation of the invention, the basic notch pitch equal to the number of notches per pole and per phase multiplied by the number of phases N.

According to one implementation of the invention, the special notch pitch is equal to the basic notch pitch minus k or to the basic notch pitch plus k, where k is an integer greater than or equal to 1.

According to one implementation of the invention, the special notch pitch is identical for all application steps.

For example, the winding is a three-phase winding with two notches per pole and per phase.

For example, the winding is a three-phase winding with 3 notches per pole and per phase.

According to one implementation of the invention, the special notch pitch is decreasing so that the first special notch pitch is equal to the basic notch pitch minus k and the following special notch pitches are respectively equal to the previous special notch pitch minus k, or the special notch pitch is progressive so that the first special notch pitch is equal to the basic notch pitch plus k and the notch pitches following special nocks are respectively equal to the previous special nock pitch plus k, where k is an integer greater than or equal to 1.

For example, for a 3-turn winding, a basic notch pitch is applied equal to the number of notches per pole and per phase multiplied by the number of phases, i.e. a basic notch pitch equal to 9 notches, no special notches used during the application steps being respectively equal to the number of notches per pole and per phase multiplied by the number of phases minus 1, i.e. 8 notches then the number of notches per pole and per phase multiplied by the number of phases minus 2 or 7 slots.

For example, the winding is a three-phase winding with 4 slots per pole and per phase.

For example, for a 4-turn winding, a basic notch pitch is applied equal to the number of notches per pole and per phase multiplied by the number of phases, i.e. a basic notch pitch equal to 12 notches, no special notches used during the application steps being respectively the number of notches per pole and per phase multiplied by the number of phases minus 1, i.e. 11 notches then the number of notches per pole and per phase multiplied by the number of phases minus 2 or 10 slots then the number of slots per pole and per phase multiplied by the number of phases minus 3 or 9 slots.

According to one implementation of the invention, at least one special notch pitch is equal to the basic notch pitch minus k and at least one other special notch pitch is equal to the basic notch pitch plus k , where k is an integer greater than or equal to 1.

For example, the winding is a three-phase winding with 1 slot plus 2 half-slots per pole and per phase.

For example, for a 4-turn winding, a basic notch pitch is applied equal to two notches per pole and per phase multiplied by the number of phases, i.e. a basic notch pitch equal to 6 notches, pitches of special slots used before a change in winding direction respectively equal to the number of slots per pole and per phase multiplied by the number of phases minus 1, i.e. 5 slots then the number of slots per pole and per phase multiplied by the number of phases plus 1 or 7 slots, then the number of slots per pole and per phase multiplied by the number of phases plus 1 or 7 slots.

For example, the winding is a three-phase winding with 4 half-slots per pole and per phase.

For example, for a 4-turn winding, a basic notch pitch is applied equal to two notches per pole and per phase multiplied by the number of phases, i.e. a basic notch pitch equal to 6 notches, pitches of special slots used before a change in winding direction respectively equal to the number of slots per pole and per phase multiplied by the number of phases plus 1, i.e. 7 slots then the number of slots per pole and per phase multiplied by the number of phases minus 1 or 5 slots then the number of slots per pole and per phase multiplied by the number of phases plus 1 or 7 slots.

According to one implementation of the invention, k is equal to 1.

According to one implementation of the invention, the number of winding steps is equal to the number of winding turns.

According to one implementation of the invention, a continuous conductor of a phase winding is formed by a single continuous wire or by a bundle of at least two continuous wires.

The invention also relates to a polyphase stator with multiple slots per pole and per phase, said stator comprising a winding comprising a number N of phase windings and being wound according to the winding method previously described and slots receiving conductors of the winding, said winding comprising for each phase winding:

- at least a portion of at least a first turn wound from a continuous conductor of a phase winding following a pitch of basic notches,

- a special notch pitch different from the basic notch pitch, so that the continuous conductor of said phase winding is housed inside a free notch adjacent to a notch in which said continuous conductor of said phase winding,

- at least a portion of at least a second turn of said continuous conductor wound according to the pitch of basic notches,

- said at least one first turn and said at least one second turn of said phase winding being continuously connected together by said continuous conductor.

According to one implementation of the invention, the winding has at least one notch receiving continuous conductors belonging to several phase windings or in that all the notches of the winding only house continuous conductors belonging to the same phase winding.

According to one embodiment of the invention, the at least a portion of at least a first turn of a continuous conductor is wound in a first direction of winding and the at least a portion of at least a second turn of said continuous conductor is wound in a second winding direction opposite to the first winding direction.

The invention further relates to a rotating electrical machine comprising a stator as defined above.

According to one embodiment of the invention, the rotating electrical machine forms an alternator or an alternator-starter or a reversible machine or an electric motor.

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

There illustrates, for a stator shown in flat projection, a three-phase winding configuration with two consecutive slots per pole and per phase without the present invention, therefore requiring an interconnector in order to connect the conductors present in two consecutive slots;

There is a perspective view of an example of a wound stator according to the present invention;

FIGS. 3a to 3h illustrate, for a stator represented in flat projection, the various stages of production of a three-phase winding with two consecutive slots per pole and per phase;

There illustrates, for a stator shown in flat projection, a three-phase winding configuration with three consecutive slots per pole and per phase;

There illustrates, for a stator shown in flat projection, a three-phase winding configuration with four consecutive notches per pole and per phase;

There illustrates, for a stator shown in flat projection, a three-phase winding configuration with one slot plus two half-slots per pole and per phase;

There illustrates, for a stator shown in flat projection, a three-phase winding configuration with four half-slots per pole and per phase;

There is a perspective view of two coils forming a phase winding made from a continuous conductor;

There is a top view of a coil of a phase winding made in a distributed wave configuration.

In Figures 2 and following, identical, similar or analogous elements retain the same reference from one figure to another.

There is a perspective view of a wound stator 10 of a rotating electric machine which mainly comprises a body 11 in which are mounted several phase windings PH1, PH2, PH3 forming an electric winding. The rotating machine is for example an alternator, alternator-starter, a reversible machine or an electric traction motor. This machine is preferably intended to be implemented in a vehicle such as a motor vehicle or a drone. It is recalled that an alternator-starter is a rotating electric machine capable of working in a reversible manner, on the one hand, as an electric generator in alternator function, and on the other hand as an electric motor, in particular for starting the heat engine of the motor vehicle. .

The machine (not shown) comprises a box on which a voltage converter such as an inverter or a rectifier bridge can be mounted. Inside this case, it further comprises a shaft, a rotor integral in rotation with the shaft and a stator 10. In this example, the stator is arranged to surround the rotor. The rotational movement of the rotor takes place around an X axis.

The rotor comprises, for example, a body formed by a stack of sheet metal sheets held in the form of a package by means of a suitable fixing system, such as rivets passing axially through the rotor right through. The rotor comprises poles formed for example by permanent magnets housed in cavities formed in the magnetic mass of the rotor. Alternatively, in a so-called "salient" pole architecture, the poles are formed by coils wound around the arms of the rotor. Still alternatively, the rotor may be a claw rotor comprising two pole wheels. Each pole wheel is made up of a plate oriented transversely, a plurality of claws forming magnetic poles and a cylindrical core. The rotor has a coil wound around the core.

The stator body 11 has an annular cylindrical shape with axis X and consists of an axial stack of flat sheets. The body 11 comprises teeth 12 distributed angularly in a regular manner on an internal circumference of a yoke 13. These teeth 12 delimit two by two notches 15. The yoke 13 corresponds to the solid annular portion of the body 11 which extends between the bottom of the notches 15 and the outer periphery of the body 11.

The notches 15 emerge axially on either side of the body 11. The notches 15 are also open radially here in the internal face of the body 11. In the embodiment examples indicated below, the stator 10 comprises 36 notches in order to facilitate understanding of the invention. Preferably, the stator 10 has no teeth to facilitate the insertion of the conductors during the winding step. Alternatively, the stator may include teeth feet to improve the electrotechnical performance of the machine. Insulators 16 are arranged in the slots 15 in order to provide electrical insulation between the conductors of the winding and the stator body 11.

To form the winding of the stator 10, a number N of phase windings corresponding to the number of phases of the electric machine are installed in the slots 15 of the body 11. In this case, the "three-phase" stator 10 comprises three windings of phases PH1, PH2, PH3. The invention is however applicable to stators comprising a different number of phase windings.

Each phase winding PH1, PH2, PH3 is constituted by a corresponding continuous conductor C1, C2, C3 bent in the form of a serpentine and wound inside the stator in the slots 15 to form a plurality of turns.

In each turn, a conductor C1, C2, C3 thus has axial strands 18 located in a series of notches 15 associated with a given phase winding PH1, PH2, PH3 as well as connecting strands 19a, 19b located alternately on each axial side of the stator body 11 and interconnecting the axial strands 18. All of the connecting strands 19a, 19b extending from one side of the body form a winding bun. The notches 15 of a series are separated from each other by a pitch of notches defined in more detail below. The winding of several concentric turns makes it possible to wind the complete phase. A turn corresponds to the winding of a conductor C1, C2, C3 on a stator turn 10.

It should be noted that each conductor C1, C2, C3 may comprise a single continuous wire or a bundle of F continuous conductor wires, F being greater than or equal to 2. In this case, the wires have a round section. Alternatively, in order to optimize the filling of the notches 15, the wires may have a rectangular, square section, or a flat shape. In certain embodiments, the wires may have axial strands 18 having a different shape from the connecting strands 19a, 19b. For example, the axial strands 18 may have a rectangular, square, or flat-shaped cross-section to optimize the filling of the notches 15, while the connecting strands 19a, 19b have a round-shaped cross-section to facilitate the conformation of the winding buns. In all cases, the conductors C1, C2, C3 are preferably made of a metallic material covered with enamel. The metallic material is preferably copper but could alternatively be aluminum or any other material suitable for the application.

The method of winding a polyphase stator 10 with multi-slots per pole and per phase comprises at least the following steps to produce each phase winding PH1, PH2, PH3:

- a step of winding at least a portion of at least a first turn Sp1 of a continuous conductor C1, C2, C3 following a pitch of basic notches P_b, while providing notches at the beginning of the first turn free between two slots 15 intended to be filled by two continuous conductors C1, C2, C3 of two adjacent phase windings PH1, PH2, PH3,

- a step of applying a different special notch pitch P_r, and in particular here less than the basic notch pitch P_b to finalize the at least one first turn, so that the continuous conductor C1, C2, C3 d a given phase winding PH1, PH2, PH3 is inserted inside a free notch 15 adjacent to a notch 15 in which said continuous conductor C1, C2, C3 of said phase winding PH1, PH2, PH3 is also inserted ,

- then a step of winding at least a portion of at least a second turn Sp2 of said continuous conductor C1, C2, C3 following the pitch of basic notches P_b,

- said at least one first turn Sp1 and said at least one second turn Sp2 of a given phase winding PH1, PH2, PH3 being continuously interconnected by said DC conductor C1, C2, C3.

Of course, as explained in more detail below, more than two turns Sp1, Sp2 can be made to obtain the desired number of layers of conductors C1, C2, C3 inside a notch 15.

In the example below, with reference to FIGS. 3a to 3h, the steps for producing a wound stator 10 of the three-phase type (N=3) with two notches per pole and per phase are described. The three-phase stator 10 has three phase windings PH1, PH2, PH3. Each phase winding PH1, PH2, PH3 is constituted by a corresponding conductor C1, C2, C3. In this case, the conductors C1, C2, C3 may each consist of a continuous wire or a bundle of at least two continuous wires. In the example shown, the stator body 11 has 36 notches and 3 pairs of poles.

More specifically, as illustrated in the , the conductors C1, C2, C3 are inserted into three separate slots 15. In this case, the conductors C1, C2, C3 are inserted simultaneously into the notches 15. Alternatively, the conductors C1, C2, C3 can be inserted one after the other. The portion of a conductor C1, C2, C3 located inside a notch corresponds to an axial strand 18. The ends of the conductors C1, C2, C3 which protrude from the body 11 and located at the level of the marks A, B , C correspond to the phase inputs E1, E2, E3 of the phase windings PH1, PH2, PH3.

Two notches 15 respectively containing an adjacent phase winding are spaced from each other by a notch left free in order to allow the subsequent insertion of the conductors C1, C2, C3 during the second turn Sp2. In other words, the conductors C1, C2, C3 are inserted inside every other notch. In the example shown, the conductors C1, C2, C3 are inserted into the slots numbered respectively 14, 16, and 18.

The conductors C1, C2, C3 are then bent to form connecting strands 19a here of substantially triangular shape, which protrude axially from the same side of the body 11. Axial strands 18 of the conductors C1, C2, C3 are then each inserted in a notch following a pitch of basic notches P_b separating two adjacent notches from a series of notches 15 associated with a turn of a phase winding PH1, PH2, PH3. The basic notch pitch P_b is equal to 2N, i.e. here P_b=6 (N being the number of phase windings and the number 2 corresponding to the number of notches per pole and per phase). The conductors C1, C2, C3 are then bent to form connecting strands 19b which protrude axially from a side opposite that of the connecting strands 19a. Thus, the connecting strands 19a, 19b are located outside the body 11 alternately on one side or the other of the body 11. All of the connecting strands 19a, 19b projecting from the same side of the body 11 forms a winding bun.

One thus continues to wind the windings of phases PH1, PH2, PH3 according to a first direction of winding K1, in particular in a first circumferential direction, and according to the pitch of basic notches P_b until the marks D, E, F located before the end of the first turn Sp1.

As illustrated by the , at the level of the connecting strands 19a, 19b of the marks D, E, F, that is to say just before the end of the first turn Sp1, a special notch pitch P_r equal to 2N-1= is applied 5 so as to insert the conductors C1, C2, C3 of the phase windings PH1, PH2, PH3 inside the slots 15 left free at the start of the first turn Sp1. In the example shown, the conductors C1, C2, C3 are inserted inside the odd notches numbered 13, 15, and 17. The winding direction is then changed in a direction K2 circumferentially opposite to the first direction K1 to achieve a second turn Sp2 using the basic notch pitch P_b. The first winding direction K1 may for example be clockwise and the second winding direction K2 may be counterclockwise or vice versa.

As illustrated by the , the second turn Sp2 is made following the pitch of basic notches P_b up to the marks G, H, I. To simplify the , the first turn is not shown.

As illustrated by the , at the level of the connecting strands 19a, 19b of the marks G, H, I, the special notch pitch P_r equal to 2N-1=5 is applied so as to insert the conductors C1, C2, C3 of the phase windings PH1 , PH2, PH3 inside even notches. We thus fall back inside the series of even numbered notches 14, 16, 18. We again change the winding direction along the direction K1 to form a third turn Sp3 by taking the basic notch pitch P_b equal at 2N=6.

As illustrated by the , the third turn Sp3 is wound up to the marks J, K, L following the pitch of basic notches P_b. To simplify the , the preceding turns are not shown.

As illustrated by the , at the level of the connecting strands 19a, 19b of the pins J, K, L, the special notch pitch P_r equal to 2N-1=5 is applied so as to insert the conductors C1, C2, C3 of the phase windings PH1 , PH2, PH3 inside the odd notches 13, 15, 17. The winding direction is again changed in the direction K2.

As illustrated by the , a fourth turn Sp4 is then formed as far as the marks M, N, O where the winding is stopped. The ends of the conductors C1, C2, C3 located at the level of the marks M, N, O correspond to the phase outputs S1, S2, S3 of the phase windings PH1, PH2, PH3.

There illustrates the winding obtained at the end of the process for which each conductor C1, C2, C3 has been represented with a different type of line. This winding is of the nested distributed wavy type. It is observed that each phase winding PH1, PH2, PH3 associated with a corresponding conductor C1, C2, C3 crosses two consecutive slots 15. A winding with two notches per pole and per phase is thus obtained without any junction between the turns insofar as one and the same continuous conductor C1, C2, C3 has been used to form each phase winding PH1, PH2, PH3.

It should be noted that in this type of winding, two consecutive turns Spi, Spi+1 are separated from each other by a change in winding direction K1, K2. The number of changes of direction is therefore equal to the total number of turns of the winding minus one. Thus, in the previous example, the production of 4 turns involved 3 changes of winding direction K1, K2.

The phase inputs E1-E3 and the phase outputs S1-S3 of the winding are in this example grouped together in the same zone. This makes it possible to simplify their connection with the voltage converter. At least one phase end of each phase winding is electrically connected to the voltage converter in order to circulate an electric current in the winding of the stator 10. It will thus be possible to easily achieve a coupling of the phase windings PH1, PH2, PH3 delta, star or according to a hybrid coupling of the triangle-star type or other.

Different embodiments of the multi-slot winding per pole and per phase are possible. Thus, the illustrates the production of a three-phase winding with 3 turns with 3 slots per pole and per phase. According to this embodiment, a basic notch pitch P_b equal to the number of notches per pole and per phase multiplied by the number of phases is applied, ie a basic notch pitch P_b equal to 9 notches. The special notch pitches P_r used before a change of winding direction K1, K2 are respectively equal to the number of notches per pole and per phase multiplied by the number of phases minus 1, i.e. 8 notches then the number of notches per pole and per phase multiplied by the number of phases minus 2, i.e. 7 slots.

There illustrates the production of a three-phase 4-turn winding with 4 slots per pole and per phase. According to this embodiment, a basic notch pitch P_b equal to the number of notches per pole and per phase multiplied by the number of phases is applied, ie a basic notch pitch P_b equal to 12 notches. The special slot pitches P_r used before a change of winding direction K1, K2 are respectively equal to the number of slots per pole and per phase multiplied by the number of phases minus 1, i.e. 11 slots then the number of slots per pole and per phase multiplied by the number of phases minus 2, i.e. 10 notches, then the number of notches per pole and per phase, multiplied by the number of phases minus 3, i.e. 9 notches.

There illustrates the production of a three-phase winding with 4 turns with 1 notch plus 2 half-notches per pole and per phase. By half-notch is meant the fact that a notch is occupied by two conductors C1, C2, C3 associated with two windings of different phases PH1, PH2, PH3. According to this embodiment, a basic notch pitch P_b equal to two notches per pole and per phase multiplied by the number of phases is applied, ie a basic notch pitch P_b equal to 6 notches. The special slot pitches P_r used before a change of winding direction K1, K2 are respectively equal to the number of slots per pole and per phase multiplied by the number of phases minus 1, i.e. 5 slots then the number of slots per pole and per phase multiplied by the number of phases plus 1 i.e. 7 notches then the number of notches per pole and per phase multiplied by the number of phases plus 1 i.e. 7 notches. Such a winding configuration makes it possible to smooth the electromotive force of the electric machine.

There illustrates the production of a three-phase 4-turn winding with 4 half-slots per pole and per phase. According to this embodiment, a basic notch pitch P_b equal to two notches per pole and per phase multiplied by the number of phases is applied, ie a basic notch pitch P_b equal to 6 notches. The special notch pitches P_r used before a change in winding direction K1, K2 are respectively equal to the number of notches per pole and per phase multiplied by the number of phases plus 1, i.e. 7 notches then the number of notches per pole and per phase multiplied by the number of phases minus 1 i.e. 5 notches then the number of notches per pole and per phase multiplied by the number of phases plus 1 i.e. 7 notches.

Alternatively, it is possible to make the winding with several notches per pole and per phase by making several winding turns before applying a special notch pitch. In the example of a winding with 2 notches per pole and per phase, said winding can be made by forming a first coil on a support, then shifting one notch pitch to apply the notch pitch special P_r and finally to wind a second reel. The two coils are connected by wire continuity and are inserted into the stator package. In this case, the method comprises a step of winding an integer M of turns Sp1-SpM of a continuous conductor C1, C2, C3 along the first direction of winding K1 to form a first coil 21.1. The method then includes a step of winding an integer M' of turns Sp1-SpM' along said second direction of winding K2 to form a second coil 21.2. The numbers of turns M, M' of each coil 21.1, 21.2 may be equal or different. Each coil 21.1, 21.2 may comprise a number of turns for example between 2 and 10. The coils 21.1, 21.2 may be obtained by winding a continuous conductor C1, C2 in the same winding direction K1, K2 or in different directions. The first coil 21.1 and the second coil 21.2 form the phase winding PH1. This process is repeated for the other phases of the winding.

The special notch pitch P_r is applied between the first coil 21.1 and the second coil 21.2 of the phase winding PH1, PH2, PH3. The first coil 21.1 and the second coil 21.2 of a given phase winding PH1, PH2, PH3 are continuously connected together by the DC conductor C1, C2, C3.

According to a particular embodiment, as illustrated by the , each coil 21.1, 21.2 may in a first assembly step be formed flat, that is to say that the turns Sp1-SpM; Sp1-SpM' each extend in a plane substantially perpendicular to axis A.

Each coil 21.1, 21.2 comprises a superposition of identical turns in the form of regular stars with axis A, axis A being coaxial with axis X of the machine. Sp1-SpM coils; Sp1-SpM' of each coil 21.1, 21.2 are made according to the pitch of basic notches P_b. The two coils 21.1, 21.2 are interconnected continuously given that the same continuous conductor C1, C2, C3 is used to produce these two coils. Portion 22 thus corresponds to the portion of DC conductor C1, C2, C3 providing the DC electrical connection between the two coils 21.1, 21.2.

In a second mounting step, the phase winding PH1, PH2, PH3 is mounted on the stator body 11 by deformation. More precisely, the winding is positioned in the notches 15 of the body 11 by progressive twisting of the axial strands 18 axially from front to rear and by simultaneous tilting of all the axial strands 18 from a direction perpendicular to the axis A towards a direction parallel to said axis A. This deformation is for example obtained by sliding an insertion block not shown here.

The insertion is carried out so that the two coils 21.1, 21.2 are inserted inside different slots 15. The connecting portion 22 makes it possible to obtain the offset between the slots of the two coils 21.1, 21.2, via the application of the special slot pitch P_r. It will thus be possible to easily obtain a wound stator 10 with two notches per pole and per phase by an offset obtained by applying a special notch pitch P_r between the two coils 21.1, 21.2.

These assembly steps are then repeated so as to insert the other phase windings to form the electrical winding.

The phase windings can thus be mounted successively one after the other in the stator body 11. However, the invention is also applicable for mounting methods in which at least two windings, or even all the windings, are mounted simultaneously in the stator body 11.

A coil 21.1, 21.2 can be made in simple corrugated as shown in the , that is to say that the connecting strands are arranged alternately on either side of the stator body 11. Alternatively, it is possible to produce a winding of the “distributed corrugated” type according to which the turns of the same coil 21.1, 21.2 are corrugated in opposition, as illustrated by the . Thus, the upper link strands 19a and the lower link strands 19b of the same coil 21.1, 21.2 are angularly offset around the axis A. The angular offset is performed in such a way that each link strand 19a, 19b comes place themselves in the free space between two successive connecting strands 19a, 19b of a previous corrugation of a conductor C1, C2, C3.

The winding steps previously described could be carried out in situ directly on the stator body 11. Alternatively, the winding steps could be carried out on a spindle then the winding obtained on the spindle is transferred inside the notches 15 of the body of the stator 11.

The present invention finds advantageous applications in the field of stators for alternators or reversible machines, but it could also be applied to any type of rotating machine.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the present invention, which would not be departed from by replacing the various elements with any other equivalents. For example, the invention is applied to an electric winding comprising more than three phases such as for example five, six, or seven phases. Thus, it will not be departing from the scope of the invention by increasing or decreasing the number of phases of the stator 10.

Claims (15)

Method of winding a polyphase stator (10) with multiple slots per pole and per phase, said stator (10) comprising slots (15) intended to receive conductors (C1, C2, C3) of a winding, said winding comprising a number N of phase windings (PH1, PH2, PH3), characterized in that said method comprises at least the following steps to produce each phase winding:
- a first step of winding at least a portion of at least a first turn (Sp1) of a continuous conductor (C1, C2, C3) of a phase winding (PH1, PH2, PH3) following a pitch base notches (P_b), so as to leave at least one free notch between two notches (15) intended to be filled by two continuous conductors (C1, C2, C3) of two phase windings (PH1, PH2, PH3 ) adjacent,
- a step of applying a special notch pitch (P_r) different from the basic notch pitch (P_b), so that the continuous conductor (C1, C2, C3) of said phase winding (PH1, PH2 , PH3) is inserted inside a free notch (15) adjacent to a notch (15) in which is also inserted said continuous conductor (C1, C2, C3) of said phase winding (PH1, PH2, PH3) ,
- then a second step of winding at least a portion of at least a second turn (Sp2) of said continuous conductor (C1, C2, C3) following the pitch of basic notches (P_b),
- said at least one first turn (Sp1) and said at least one second turn (Sp2) of said phase winding (PH1, PH2, PH3) being continuously interconnected by said DC conductor (C1, C2, C3). Method according to Claim 1, characterized in that the at least a portion of at least a first turn (Sp1) of a continuous conductor (C1, C2, C3) is wound in a first winding direction (K1) and the at least a portion of at least a second turn (Sp2) of said continuous conductor (C1, C2, C3) is wound in a second winding direction (K2) opposite to the first winding direction (K1). Method according to Claim 1 or 2, characterized in that to produce each phase winding (PH1, PH2, PH3):
- the first winding step comprises the winding of an integer number M of turns of the continuous conductor (C1, C2, C3) to form a first coil (21.1),
- the second winding step comprises the winding of an integer number M' of turns of said continuous conductor (C1, C2, C3) to form a second coil (21.2),
- the special notch pitch (P_r) being applied between the first coil (21.1) and the second coil (21.2) of the phase winding (PH1, PH2, PH3),
- said first coil (21.1) and said second coil (21.2) of said phase winding (PH1, PH2, PH3) being continuously connected together by said DC conductor (C1, C2, C3). Method according to any one of the preceding claims, characterized in that the phase windings (PH1, PH2, PH3) are wound simultaneously or one after the other. Method according to any one of the preceding claims, characterized in that it comprises several steps of applying a special notch pitch (P_r) and several winding steps following the basic notch pitch (P_b), each application step being preceded by a winding step and followed by another winding step, the turns of said phase winding (PH1, PH2, PH3) obtained by the winding steps being continuously connected together by said continuous conductor (C1, C2, C3). Method according to the preceding claim, characterized in that the special notch pitch (P_r) is equal to the basic notch pitch (P_b) minus k or to the basic notch pitch (P_b) plus k, k being a whole number greater than or equal to 1. Process according to claim 5 or 6, characterized in that the special notch pitch (P_r) is identical for all application steps. Process according to Claim 5, characterized in that:
- the special notch pitch (P_r) is decreasing so that the first special notch pitch is equal to the basic notch pitch (P_b) minus k and the following special notch pitches are respectively equal to the no previous special notch minus k, or
- the special notch pitch (P_r) is progressive so that the first special notch pitch is equal to the basic notch pitch (P_b) plus k and the following special notch pitches are respectively equal to the no previous special notch plus k,
- k being an integer greater than or equal to 1. Method according to Claim 5, characterized in that at least one special notch pitch (P_r) is equal to the basic notch pitch (P_b) minus k and in that at least one other special notch pitch (P_r) is equal to the basic notch pitch (P_b) plus k, where k is an integer greater than or equal to 1. Process according to any one of Claims 6 to 9, characterized in that k is equal to 1. Method according to any one of the preceding claims, characterized in that the number of winding steps is equal to the number of turns of the winding. Method according to any one of Claims 1 to 11, characterized in that a continuous conductor (C1, C2, C3) of a phase winding (PH1, PH2, PH3) is formed by a single continuous wire or by a bundle of at least two continuous threads. Polyphase stator (10) with multiple slots per pole and per phase, said stator (10) comprising a winding comprising a number N of phase windings (PH1, PH2, PH3) and being wound according to the winding method according to any one of the preceding claims and slots (15) receiving conductors (C1, C2, C3) of the winding, said winding comprising for each phase winding:
- at least a portion of at least a first turn (Sp1) wound from a continuous conductor (C1, C2, C3) of a phase winding (PH1, PH2, PH3) following a notch pitch of basis (P_b),
- a special notch pitch (P_r) different from the basic notch pitch (P_b), so that the continuous conductor (C1, C2, C3) of said phase winding (PH1, PH2, PH3) is housed at the inside a free notch (15) adjacent to a notch (15) in which said continuous conductor (C1, C2, C3) of said phase winding (PH1, PH2, PH3) is also housed,
- at least a portion of at least a second turn (Sp2) of said continuous conductor (C1, C2, C3) wound according to the pitch of basic notches (P_b),
- said at least one first turn (Sp1) and said at least one second turn (Sp2) of said phase winding (PH1, PH2, PH3) being continuously interconnected by said DC conductor (C1, C2, C3). Stator (10) according to the preceding claim, characterized in that the winding has at least one notch (15) receiving DC conductors (C1, C2, C3) belonging to several phase windings (PH1, PH2, PH3) or in that that all the notches (15) of the winding accommodate only DC conductors (C1, C2, C3) belonging to the same phase winding (PH1, PH2, PH3). Rotating electrical machine comprising a stator as defined in claim 13 or 14.