FR3083651A1 - STATOR COIL FOR A ROTATING ELECTRIC MACHINE - Google Patents

Abstract

The invention relates mainly to a stator for a rotary electric machine comprising: - a stator body (29) comprising several stator segments (20) having fixing means for forming said body and - an electric winding comprising several windings forming phases , each phase being formed of a single conductor (11) having axial portions (15) housed inside notches (12 ') of the stator body (29) and connection portions (16) ensuring a connection between the axial portions (15).

Description

COILED STATOR FOR A ROTATING ELECTRIC MACHINE

The present invention relates to a wound stator for a rotary electrical machine and its production method. The invention finds a particularly advantageous application for a stator of a rotary electric machine such as for example an alternator, an alternator-starter, a reversible machine or an electric motor.

In a manner known per se, rotary electrical machines comprise a stator and a rotor secured to a shaft. The electric machine has a housing carrying the stator. This housing is configured to carry the rotor shaft in rotation, for example by means of bearings.

The rotor is for example a claw rotor which has two pole wheels. In another example, the rotor comprises a body formed by a stack of sheets of metal sheets held in the form of a package by means of a suitable fixing system, such as rivets axially passing through the rotor. The rotor has poles formed for example by permanent magnets housed in cavities formed in the magnetic mass of the rotor, as described for example in document EP0803962. Alternatively, in a so-called salient pole architecture, the poles are formed by coils wound around the rotor arms.

The stator comprises a body constituted by a stack of thin sheets forming notches as well as a winding received in notches of the stator open inwards. In stators of this kind, the most commonly used types of windings are, on the one hand, the so-called concentric windings constituted by coils wound around the teeth of the stator, and on the other hand, the coils of the so-called wavy type, which are described for example in document FR2483702.

The corrugated winding comprises a plurality of phase windings, of the type in which each winding comprises at least one spiral conductor of which each turn forms undulations traversing the notches of the body. These conductors have connecting portions located alternately on each side of the stator body connecting together axial portions located inside the notches of the stator.

The document EP2124317 teaches the production of a winding requiring the implementation of specific operations of electrical connections between different parts of the winding in order to reconstruct the electrical circuit of the machine. These operations generate additional costs and also present problems of reliability of the connections.

The invention aims to effectively remedy these drawbacks by proposing a stator for a rotary electric machine comprising a stator body comprising several stator segments having fixing means for forming said body and an electric winding comprising several windings forming phases, each phase being formed of a single conductor having axial portions housed inside notches of the stator body and connecting portions ensuring a connection between the axial portions.

The invention thus makes it possible, thanks to the use of a single wire to form a phase, to eliminate the operations of connecting the turns when carrying out the winding. In addition, the fact of reconstituting the stator body makes it possible to adapt to all the desired stator dimensions and to simplify the manufacturing process by facilitating the step of inserting the winding into the stator body.

According to one implementation, each stator segment comprises at least one tooth and a yoke portion, said yoke portion having at its ends zones of connection with a yoke portion of an adjacent stator segment.

According to one implementation, the stator comprises an axial holding member housed in openings made in adjacent cylinder head portions.

According to one implementation, the stator body comprises a cylinder head having a plurality of housings and each stator segment comprises at least one tooth, the segments being fixed to the cylinder head by latching means, such as dovetails , cooperating with the accommodation.

According to one implementation, that the teeth are each provided with a tooth foot.

According to one implementation, the stator has 2, 4, 6 or 8 conductors per notch.

According to one implementation, the conductor has a round section. Alternatively, the conductor can have a rectangular section.

According to one implementation, the axial portions of the winding have a rectangular section and the connecting portions have a round section. This shape is for example obtained by stamping one of the portions.

According to one implementation, for two adjacent notches of a series of notches associated with a phase winding, the winding has two connecting portions connecting axial portions located in said adjacent notches.

The invention also relates to a method for producing a wound stator of a rotating electrical machine. The method comprises: a step of producing a winding ply comprising several windings forming phases, each phase being formed of a single conductor having axial portions intended to be inserted inside notches of the stator and portions connecting ensuring a connection between the axial portions; a step of producing a preformed winding by winding the winding ply; and a step of reconstituting a stator body by radial insertion of stator segments inside spaces of the winding extending between successive axial portions and by assembly of the means for fixing the corresponding stator segments.

According to one implementation, the stator segments are inserted radially from the outside towards the inside of the winding with respect to an axis of the stator.

According to one implementation, said method comprises a step of inserting the holding members in openings made in the cylinder head portion.

According to one implementation, the stator segments constituted by teeth are inserted radially from the inside towards the outside of the winding with respect to an axis of the stator.

According to one implementation, the insertion of the stator segments is carried out in two stages by first inserting a first group of segments and then a second group of segments so as to avoid any interference between said segments.

According to one implementation, said method comprises firstly a step of inserting the stator teeth inside the spaces of the winding and then a step of fixing the teeth to a cylinder head of the stator.

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 shows a perspective view of a comb provided with notches on which is made a winding ply used in the method according to the invention.

Figure 2 is a view of the winding ply.

Figure 3 is a perspective view of a preformed winding obtained from the winding ply.

FIG. 4a is a perspective view of a first embodiment of a wound stator according to the invention in which stator segments are inserted from the outside towards the inside of the winding.

Figure 4b is a perspective view of a stator segment used with the wound stator of Figure 4a.

Figure 4c is a perspective view of a second type of stator segment that can be used with the wound stator of Figure 4a.

FIG. 5a is a perspective view of a second embodiment of a wound stator according to the invention in which segments are inserted from the inside towards the outside of the winding.

Figure 5b is a perspective view of a tooth used with the wound stator of Figure 5a.

Figure 6a is a perspective view of an alternative embodiment of the wound stator of the second embodiment of the invention.

Figure 6b is a perspective view of a tooth used with the wound stator of Figure 6a.

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

FIGS. 1 and 2 show an example of a winding ply 10 intended to be used to manufacture a wound stator 14. This winding ply 10 comprises two layers of continuous conductors 11 superimposed on each other. There is thus a lower layer of conductor located on the bottom side of the notches 12 of a comb 13 and an upper layer located on the side of the opening of the notches 12 of the comb 13.

Each conductor 11 of the sheet 10 obtained forms longitudinal corrugations successively comprising an axial portion 15 which is received in an associated notch 12, a connecting portion 16 which extends opposite the lower lateral face of the comb 13 , an axial portion 15 consecutive which is received in a consecutive associated notch 12, a connecting portion 16 which extends opposite the upper lateral face of the comb 13.

The notches 12 are associated in series with the conductors 11 of a phase winding E1-En. Thus, the notches 12 of a series of notches receive the axial portions 15 of the conductors 11 constituting a phase winding E1-En. Each series of notches 12 is associated with one of the n phase windings E1-En. Thus, two consecutive notches 12 of the same series of notches are separated by notches 12, each of which belongs to one of the other series of notches 12. The notches 12 of each set of notches 12 associated with a winding of phase E1-En are thus distributed over the transfer comb 13 at a constant pitch equal to the number of phases. If the number n of phases is equal to 6, the notch pitch is therefore worth 6.

Furthermore, the sheet 10 is preferably of the corrugated distributed type, that is to say that for two adjacent notches 12 of a series of notches associated with a phase winding E1-In given, the winding sheet 10 has two connecting portions located on either side of the ply 10 connecting axial portions 15 located in said adjacent notches 12.

The sheet 10 also includes first ends of conductors 11 forming phase inputs 11-In and second ends of conductors 11 forming phase outputs 01-On. For a three-phase double winding, there are six phase inputs 11-16 and six phase outputs 01-06. Each phase is therefore well formed of a single conductor 11. For example, there are six conductors 11 to form the six phases of the winding.

As can be seen in Figure 3, the winding ply 10 is wound to obtain a preformed winding 18 having a generally cylindrical shape. By carrying out N turns, 2N conductors per notch 12 ′ are obtained due to the configuration with two layers of ply 10. In the example shown, two turns are made to have four conductors per notch, ie four axial portions 15 to the inside each notch 12. However, the number of turns can be adapted to obtain in particular 2, 4, 6, or 8 conductors per notch.

The conductors 11 comprise axial portions 15 intended to be inserted inside the notches 12 ′ of the stator body. The axial portions 15 are angularly spaced apart from one another by a regular pitch. The conductors 11 also include the connecting portions 16 ensuring a connection between the ends of the axial portions, as described above.

As illustrated by FIG. 4a, a set of segments 20 angularly spaced apart from each other in a regular manner are arranged around the winding 18 at a distance greater than that of the external diameter of the winding 18.

The segments 20 are then brought radially from the outside towards the inside of the coil 18 in the direction D1, so that the teeth 21 of the segments 20 penetrate inside the spaces 22 extending between successive axial portions 15 of the winding 18. In order to facilitate the insertion of the segments 20 inside the spaces 22, the teeth 21 are advantageously devoid of tooth foot.

As can be seen in FIG. 4b, each segment 20 comprises a tooth 21 and a cylinder head portion 25, said cylinder head portion 25 comprising at its ends connecting zones 26.1, 26.2 complementary. A male zone 26.1 and a female zone 26.2 are thus distinguished, so that during the positioning of the segments 20, a male zone 26.1 of a segment 20 cooperates with a female zone 26.2 of an adjacent segment 20. Alternatively, a segment may have two male parts and an adjacent segment two female parts.

As a variant, as shown in FIG. 4c, the connection zones are mixed and each have a male zone 26.1 and a female zone 26.2. At each junction between two adjacent segments 20, two male zones 26.1 are superposed axially on each other and each cooperate with a corresponding female zone 26.2. Axial retaining members 27 can be inserted into openings 28 formed in the cylinder head portion 25 and more precisely in the male zones 26.1 in order to hold the adjacent segments 20 between them. A holding member 27 could for example be made up of two half-rivets or a bulking.

Once the stator segments 20 are assembled together, the stator body 29 comprising the annular yoke 32 and the teeth 21 is reconstituted. The teeth 21 delimit two by two the notches 12 ′ of the stator 14 inside which the axial portions 15 are inserted.

According to another implementation of the invention shown in FIGS. 5a and 6a, the stator segments 20 are inserted radially from the inside towards the outside of the winding 18 in the direction D2.

In this case, the segments 20 of the stator are constituted by teeth 21 inserted inside the spaces 22 of the winding 18 and then fixed to a cylinder head 32 of annular shape arranged around the winding 18. The stator body 29 is thus reconstituted comprising the cylinder head 32 and the teeth 21.

In order to avoid any interference between the teeth 21 during their initial positioning on an internal diameter smaller than the final diameter of the stator 14, the insertion of the teeth 21 is carried out in two stages by first inserting a first part of the teeth 21 and then a second part of the teeth 21 of the stator 14 from the internal diameter to the external diameter.

As can be seen in FIGS. 5a and 5b, the teeth 21 can be fixed to the cylinder head 32 by means of dovetails 33. A dovetail 33 is formed in a radial end of each tooth 21 and is intended to cooperate with a housing 34 of corresponding shape produced in an internal face of the cylinder head 32.

According to another embodiment shown in FIGS. 6a and 6b, the teeth 21 may be fixed to the cylinder head 32 by latching means 35. These latching means 35 are for example formed by two elastically deformable lugs 36 inclined by relative to an axis of the tooth 21 and intended to be inserted inside a housing 37 of corresponding shape formed in the internal face of the cylinder head 32.

The advantage of the radial insertion from the inside to the outside of the winding is that the teeth 21 can each be provided with a tooth foot 39 in order to improve the electromagnetic performance of the electric machine.

According to a particular embodiment, the axial portions 15 of the ply 10 are stamped so as to have a rectangular section and the connecting portions 16 have a round section. Alternatively, the conductors have a round section or a rectangular section along their entire length.

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, variations, 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.

Claims (10)

1. Stator for a rotary electric machine comprising: - a stator body (29) comprising several stator segments (20) having fixing means for forming said body, and an electrical winding comprising several windings forming phases, each phase being formed of a single conductor (11) having axial portions (15) housed inside notches (12 ') of the stator body (29) and connecting portions (16) providing a connection between the axial portions (15). 2. Stator according to the preceding claim, characterized in that each stator segment (20) comprises at least one tooth (21) and a cylinder head portion (25), said cylinder head portion (25) comprising at its ends zones of connection (26.1,26.2) with a cylinder head portion of an adjacent stator segment (20). 3. Stator according to the preceding claim, characterized in that it comprises an axial holding member (27) housed in openings (28) formed in adjacent cylinder head portions (25). 4. Stator according to claim 1, characterized in that the stator body comprises a cylinder head (32) having a plurality of housings (34, 37) and in that each stator segment (20) comprises at least one tooth (21 ), the segments being fixed to the cylinder head by latching means (33, 35), such as dovetails (33), cooperating with the housings (34, 37). 5. Stator according to the preceding claim, characterized in that the teeth (21) are each provided with a tooth foot (39). 6. Stator according to claim 4 or 5, characterized in that the axial portions (15) of the winding have a rectangular section and the connecting portions (16) have a round section. 7. Method for producing a wound stator (14) of a rotary electric machine, characterized in that it comprises: a step of producing a winding ply (10) comprising several windings forming phases, each phase being formed of a single conductor (11) having axial portions (15) intended to be inserted inside notches (12 ') of the stator (14) and of the connecting portions (16) ensuring a connection between the axial portions (15), a step of producing a preformed winding (18) by winding the winding ply (10), and - A step of reconstituting a stator body (29) by radial insertion of stator segments (20) inside spaces (22) of the winding (18) extending between successive axial portions (15) and by assembling the means for fixing the corresponding stator segments. 8. Method according to the preceding claim, characterized in that the stator segments (20) are inserted radially from the outside towards the inside of the winding (18) relative to an axis of the stator. 9. Method according to claim 7, characterized in that the stator segments (20) are inserted radially from the inside to the outside of the winding (18) relative to an axis of the stator. 10. Method according to claim 9, characterized in that the insertion of the stator segments (20) is carried out in two stages by first inserting a first group of segments and then a second group of segments so as to avoid any interference between said segments.