FR3023080A1 - INDUCED ROTATING ELECTRIC MACHINE WITH OPTIMIZED NOTCH FILLING - Google Patents

Abstract

The invention relates mainly to an armature (11) of rotating electrical machine comprising: - a body (10) comprising at least one notch (17) formed in said body (10), said notch (17) opening axially from said body (10); ), - at least one conductor (24) comprising: - at least one internal portion (241 ', 242') located in said notch (17), and - at least one external portion (25) extending beyond said notch (17), said outer portion (25) of said conductor (24) having, over its entire length, a section different from said inner portion (241 ', 242').

Description

The invention relates to an optimized rotating electric machine armature with optimized slot filling. The invention finds a particularly advantageous, but not exclusive, application with motor vehicle starter rotors. The armature of an electric machine consists either of a rotor in the case of a machine belonging to a starter, or a stator in the case of an alternator. The armature comprises a body generally made of a stack of thin-walled sheets so as to form a bundle of sheets. This body is provided with notches opening axially on both sides of the body. These notches also open radially towards the inside of the armature in the case of the stator or outwardly in the case of the rotor. These notches regularly spaced angularly on the periphery of the armature are each delimited by two successive teeth. The armature further comprises conductors forming the winding. These conductors each comprise at least one internal portion located in a given notch; and at least one outer portion extending beyond the notch. It is known from US7808148 to deform the inner portions of the conductors. However, such a deformation performed locally and only on an extreme layer of conductors aims to keep the conductors inside the notches and has no influence on the magnetic performance of the machine. The aim of the invention is to improve the magnetic performance of the machine by proposing an armature of a rotating electrical machine comprising: a body comprising at least one notch formed in said body, said notch emerging axially from said body, at least one conductor comprising: at least one internal portion located in said notch, and at least one external portion extending beyond said notch, said external portion of said conductor having, over its entire length, a section different from a section of said internal portion, in particular a section different from any section of said inner portion (241 ', 242'). The invention thus makes it possible, because of the configuration of the conductors, to maximize the volume of conductors inside the notches of the body of the armature, and thus to increase the power of the machine. "Outer portion of said conductor having, over its entire length, a different section of said inner portion", a section difference visible to the naked eye. Thus, each section of the inner portion of the conductor is different from any section of the outer portion of said conductor. The notch can open axially on both sides of the body. This particular embodiment makes it possible to simplify the production of such a rotating electrical machine. In one embodiment, said inner portion of the at least one conductor is clamped along a length of said notch. In other words, the inner portion has, throughout its length, a shape allowing it to occupy the maximum internal space of the notch. Such clamping optimizes the volume of conductors inside the notches.

According to one embodiment, said inner portion comprises a surface conforming to a face of said notch along an entire length of said notch. This makes it possible to improve the thermal resistance of the armature by allowing a better heat exchange between the armature and the conductors. According to one embodiment, at least one notch comprises at least two radially aligned conductors, each of the internal portions of said conductors being in contact with at least one same face delimiting said notch.

For example, at least one notch comprises four radially aligned conductors. The inner portions of the at least two conductors may be in contact with each other.

Said contact between the internal portions of the at least two conductors may be formed by a face of an inner portion of a conductor matching a face of an inner portion of another conductor, saidites being notably substantially planar. According to one embodiment, the sum of the largest lengths measured radially of each of said outer portions of said conductors in contact with at least one and the same face of said notch is greater than a depth of said notch. According to one embodiment, the measurement of each length of said external portions is carried out in a plane orthogonal to an axis of said body, said plane intersecting the outer portion of said conductors and being located at a distance of less than 2 mm from an axial end face. said body, in particular said plane being in contact with an axial end face of said body. In one embodiment, the one or more inner portions have cross sections having a maximum dimension measured in an ortho-radial direction greater than a maximum dimension measured in a radial direction. According to one embodiment, said armature further comprises a radial retaining device of the internal portion or portions located in said notch. Such a radial retainer allows the conductor to be held within the notch. In one embodiment, said radial retainer comprises lugs extending on either side of teeth delimiting said notch so as to at least partially close said notch.

In one embodiment, said retaining device comprises a part overmolded around an outer periphery of said body. In one embodiment, said notch has non-parallel edges. According to one embodiment, said notch is flat-bottomed or with a rounded bottom.

In one embodiment, said notch is covered with a notch insulation. In one embodiment, the conductor or conductors each consist of a pin. According to one embodiment, said armature consists of a starter rotor of a motor vehicle.

According to another embodiment, said armature consists of a motor vehicle alternator stator. The invention furthermore relates to a method of producing an armature of an electric machine comprising a body comprising at least one notch formed in said body, said notch emerging axially from said body, said method comprising - an insertion step, at least one inside said notch, at least a portion of a conductor, such that the at least one conductor portion radially exceeds at least part of said notch, and - a step of deformation of said conductor portion of so that said protruding portion is found within said notch, over the entire length of the notch. According to one embodiment, the deformation step consists in clamping the conductor portion by means of a blade along at least a whole axial length of said notch.

According to one embodiment, the tightening of the conductor portion can be achieved by crushing said portion of conductor in the notch. In other words, said portion of conductor may be in the notch prior to the deformation step.

According to one embodiment, said method further comprises a step of at least partial closure of said notch, for holding the at least one conductor radially inside the notch. According to one embodiment, the step of at least partially closing said notch consists in producing tabs in teeth delimiting said notch. According to one embodiment, the tabs are made by crushing the armature, in particular by crushing the laminations of the armature. According to one embodiment, the step of at least partial closure of said notch consists in overmolding a piece around an outer periphery of said body. The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative but not limiting of the invention. FIG. 1 is a perspective view of a body of a vehicle starter rotor with which the winding method according to the present invention is carried out; Figure 2 is a perspective view of a pin used to make the armature according to the present invention; Figure 3a is a cross-sectional view of conductors located in notches of the rotor prior to performing the clamping step; Figure 3b is a cross-sectional view of the conductors located in notches of the rotor after completion of the clamping step; Figure 3c is a partial longitudinal sectional view of the rotor showing conductors located in the notches following the completion of the clamping step; Figure 3d shows a partial sectional view of the notches of the rotor following the implementation of a step of partially closing said notches; Figure 4 shows an alternative embodiment of the method with notches rounded bottom; FIG. 5 shows an alternative embodiment of the method in which four conductors are notched in two different rows; Figure 6 is a perspective view of the mounted rotor of the motor vehicle starter according to the present invention; Figure 7 is a top view of an alternator stator with which is implemented the method of producing a winding according to the present invention. Identical, similar or similar elements retain the same reference from one figure to another. FIG. 1 shows a body 10 of a motor vehicle starter rotor 11 having an axis X. This body 10 in the form of a bundle of sheets has an external periphery 12 of cylindrical shape delimited axially by two axial end faces 13, 14. This body 10 is provided with notches 17 opening axially on either side of the body 10 and radially outwardly of the rotor 11. These notches 17 are spaced regularly angularly on the periphery of the body 10. These notches 17 are delimited each by two successive teeth 18 from a central hub 19 in which is formed an opening 20 for a fitting of a shaft 22 of the electric machine (see Figure 6). More precisely, as can be seen in FIGS. 3a and 3b in particular, each notch 17 is delimited by two lateral faces 181, 182 opposite two consecutive teeth 18, as well as by a bottom 21 corresponding to a portion the central hub 19 extending between the two faces 181, 182. The notches 17 have in this case a bottom 21 of flat shape, but could alternatively have a bottom 21 of rounded shape, as shown in Figure 4.

The notches 17 are said non-parallel edges, that is to say that the faces 181, 182 vis-à-vis delimiting a notch 17 are not parallel to each other. Alternatively, the notches 17 may be parallel edges. In this case, the lateral faces of each tooth 18 are inclined with respect to each other. To form the winding, a set of conductors 24 is inserted inside the notches 17. It should be noted in this respect that the teeth 18 are devoid of a tooth root to facilitate the insertion of the conductors 24 inside the notches 17 .

The conductors 24 coated with a thin electrically insulating layer, such as enamel, may for example be made of copper or aluminum. Preferably, as can be seen in FIG. 2, each conductor 24 has a pin shape. Each conductor 24 thus comprises two branches 241, 242 connected by a connecting section 243 so as to have a U shape. Hereinafter described with reference to FIGS. 3a to 3d, the various steps of the method according to the invention to maximize the filling of the notches 17. In a first step, a notch insulation 27 is positioned so as to cover the inner faces 181, 182, 21 of the notches 17. This insulator 27 makes it possible not to injure the conductors 24 during their mounting in the sheet package, and also electrically insulates the conductors 24 from the plate package connected to ground via the starter housing. The conductors 24 are then threaded axially inside the notches 17 on two distinct layers: the upper layer (furthest from the bottom 21) and the lower layer (closest to the bottom 21). If one of the branches 241 of a given conductor is positioned in the lower layer then the other branch 242 is in the upper layer and vice versa.

Thus, as is clearly visible in FIG. 3a, two branches 241, 242 of two distinct conductors 24 are located in the same notch 17.

The section of the conductors 24 is in this case round. Due to the reduction of the width of the notch 17 when moving towards the bottom 21 of the notch 17, the branch 241 located in the lower layer has a diameter preferably slightly smaller than the diameter of the branch 242. located in the upper layer. Preferably, before deformation, the conductors 24 all have the same diameter, this having the effect of obtaining the same electrical resistance. Once deformed, the conductors follow the shape of the notch 17 even if the width of the notch 17 decreases towards the X axis, the width being measured in a plane orthogonal to the axis X. It should be noted that the The sum of the longest radially measured lengths of each of the branch sections 241, 242, here constituted by the sum of the diameters L1, L2 of the branch sections, is greater than the depth L7 of the notch 17 measured in a radial direction.

In other words, the branch 242 located in the upper layer radially exceeds at least part of the notch 17. In this case, the length of the portion of the branch 242 located outside the notch 17 is approximately equal to the The diameter of a conductor 24 being, for example, of the order of 2 millimeters, the branch 242 protrudes approximately 1 mm from the notch 17. A deformation step shown on FIG. Figure 3b. This step consists in crushing the branches 241, 242 by means of a blade 29 over the entire axial length of the notch 17, by applying a crushing force F1 going from the outside towards the inside of the body 10 of the rotor 11.

The part of the branch 242 that was located outside the notch 17 then penetrates inside the notch 17. The branches 241, 242 deform to take the form of the notch 17 and fill the spaces between the branches 241, 242 and the internal faces 181, 182. This maximizes the volume of conductors 24 inside the notches 17.

In the remainder of the description, internal portions 241 ', 242' are defined as being the parts of the conductor 24 positioned inside the notches 17 and the outer portions 25 as being the parts of the conductor 24 extending to the beyond the notches 17, namely the connecting portion 243 and the free ends of the branches 241, 242 positioned outside the notches 17. The outer portions 25 of the conductors 24 projecting from the end faces 13, 14 of the body 10 form the buns 26 of the winding positioned on either side of the rotor 11 (see Figure 6). Due to the deformation, the internal portions 241 ', 242' are in contact with the lateral faces 181, 182 vis-à-vis delimiting the notch 17, via the notch insulation 27. The internal portions 241 ' , 242 'are then tightened along the entire axial length of the notch 17. "Tightened" means that the internal portions 241', 242 'are closely held by the side faces 181, 182 of the notches 17 taking into account the absence of clearance between the side faces 181, 182, the notch insulation 27, and the inner portions 241 ', 242'. As can be seen in FIG. 3b, the internal portions 241 ', 242' present, in this case, transverse sections having a maximum dimension L3 measured in an ortho-radial direction greater than a maximum dimension L4 measured in a radial direction. The faces in contact of the two inner portions 241 'and 242' are substantially planar. In addition, the inner portion 241 'located in the lower layer comprises a surface conforming to the bottom 21 of the notch 17 over the entire axial length of the notch 17. This contact surface thus has a substantially flat shape in the case of a notch 17 with a flat bottom as can be seen in FIG. 3b, or a rounded shape in the case of a notch 17 with a rounded bottom as can be seen in FIG. 4.

As illustrated in FIG. 3c, since the outer portions 25 of the conductors 24 have not been deformed during the deformation step, there is then a difference in section between an inner portion 241 ', 242' and an outer portion 25. corresponding to a conductor 24. This section difference is characterized by a difference in size and / or shape between the sections of the inner portions 241 ', 242' and outer 25 of a conductor 24 which is visible to the naked eye . This difference is observable in any section of the inner portion 241 ', 242'.

In one embodiment, the outer portions 25 of the conductors 24 may be pushed by the deformation step. Thus, the outer portions 25 can be folded toward the X axis without exceeding the sheet package. This makes it possible to prevent said external portions of the bun from coming into contact with the inductor. According to another embodiment, the deformation step bends the outer portions 25 towards the X axis. According to an example of this embodiment, the deformation step bending the outer portions deforms, at least a portion of the portions. external 25, in particular by contact one on the other. The outer portions 25 being less deformed than the inner portions 241 ', 242'. In addition, the sum of the longer lengths L5, L6 measured radially of each of the outer portions 25 of conductors located in the same notch 17 is greater than the depth L7 of the notch 17. In this case, the sum of the two diameters L5, L6 of the two outer portions of the conductors 24 inserted in the notch 17 is greater than the depth L7 of the notch 17. It should be noted in this regard that the measurement of each length L5, L6 of the outer portions 25 is performed in an orthogonal plane P to the X axis of the rotor 11. This plane P, intersecting the outer portions 25 of the conductors 24, is located at a distance of less than 2 mm from an axial end face 13, 14 of the body 10. The measurement may in particular be made in a plane P in contact with an axial end face 13, 14 of the body 10. The rotor 11 rotating at high speed, of the order of 15000 to 20000 revolutions / min, is carried out. preferably tabs 28 ensuring a radial retention of the p internal orifices 241 ', 242' located in the notches 17. For this purpose, as can be seen in FIG. 3d, punches 31 each having a central portion intended to come into contact with a face of the internal portion 242 'and two side portions forming a shoulder intended to deform a border of the tooth 18 for the creation of the tabs 28. The tabs 28 extending on either side of each tooth 18 thus provide a partial closure of the notches 17.

In an exemplary implementation, for a rotor 11 having a length of the order of 55 mm, four punches 31 each having a diameter of the order of 5 mm are used, two successive punches 31 being separated from one another by distance of the order of 1 mm.

Alternatively or in addition to the tabs 28, the retaining device comprises an overmolded piece 34 around the outer periphery 12 of the body 10. The overmolded piece 34 of annular shape will preferably be made of an electrically insulating material, for example plastic. According to another embodiment not shown, the armature is identical to one of the preceding embodiments except that each notch 17 comprises a row of four radially aligned conductors. In the embodiment of Figure 5, is inserted in a notch 17 given, two sets of two conductors 24 in two different radial rows R1, R2. In each set, the internal portions 241 ', 242' lie in the same radial plane and have a face in contact with the same face 181, 182 delimiting the notch 17. In this case, the deformation step in a Notch is performed simultaneously on all conductors 24 located in this slot 17. In another alternative embodiment (not shown), all 20 conductors 24 are positioned on a single layer. A single conductor portion 24 is then inserted by notch 17. Before deformation, the portion of the conductor 24 inserted in the notch 17 may comprise a maximum radial dimension greater than the depth L7 of the notch 17. In the rotor 11 ended shown in FIG. 6, the free ends of the branches 241, 242 of the conductors 24 are welded to the electrically conducting strips 37 of a collector 38. The strips 37, for example made of copper, are carried by a plastic support 39 solidary of the tree. The support 39 of the collector 38 is, for a good temperature resistance, thermosetting plastic material, such as a thermosetting phenolic plastic material for example Bakelite. In this case, the manifold 38 which has lamellae 37 extending longitudinally side by side on the outer periphery of the support 39 is of the "drum" type. However, alternatively, the manifold 38 used may be a flat type collector. To ensure radial retention of the conductors 24 in the buns 26 and thus avoid the effects of centrifugal force, the hoop 41 are positioned around the buns 26. These hoop 41 are preferably made of electrically insulating material. The rotor 11 may comprise at one end of its shaft 22 a gear wheel 44 located on the opposite side of the collector 38 and intended to form a sun gear in a planetary gear reduction system 10 of a starter, as described by FIG. example in the document FR2787833. Alternatively, the invention may be implemented with a stator belonging to an alternator. As can be seen in FIG. 7, such a stator 47 comprises a Y-axis body 48 having an annular cylindrical shape consisting of an axial stack of plane sheets. The body 48 has notches 49 which open axially on either side of the body 48. However, unlike the rotor 11, the notches 49 are radially open in the internal cylindrical face of the body 48. These notches 49 are each delimited by two successive teeth 50. More precisely, each notch 49 is delimited by two faces facing the teeth 50 as well as by the part of the yoke 51 extending between the two faces. This yoke 51 corresponds to the solid portion of the body 48 extending between the bottom of the notches 49 and the outer periphery of the stator. Preferably, the teeth 50 are toothless to facilitate the insertion of the conductors 24 inside the notches 49. The method may be implemented by inserting portions 241, 242 of conductors 24 into the notches 49. then performing a deformation step by applying a force F2 by means of the crushing blade 29 from the inside to the outside of the body 48 of the stator 47. The at least partial closure of the notches 49 may also be carried out from analogous way by the formation of tabs and / or the realization of overmolding.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention of which one would not go out by replacing the details of execution by any other equivalents.

Claims (15)

REVENDICATIONS1. Induction (11, 47) of rotating electrical machine comprising: - a body (10) comprising at least one notch (17) formed in said body (10), said notch (17) opening axially from said body (10), - at least a conductor (24) comprising: - at least one inner portion (241 ', 242') located in said notch (17), and - at least one outer portion (25) extending beyond said notch (17) said outer portion (25) of said conductor (24) having, over its entire length, a section different from a section of said inner portion (241 ', 242'), in particular a section different from any section of said inner portion ( 241 ', 242'). 2. An armature according to claim 1, wherein said inner portion (241 ', 242') of the at least one conductor (24) is clamped along an entire length of said notch (17). An armature according to any one of claims 1 to 2, wherein said inner portion (241 ', 242') comprises a surface conforming to a face of said notch (17) along an entire length of said notch (17). 4. An armature according to any one of claims 1 to 3, wherein at least one notch (17) comprises at least two conductors (24) aligned radially, each of the inner portions (241 ', 242') of said conductors (24) being in contact with at least one same face (181, 182) delimiting said notch (17). 5. An armature according to claim 4, wherein the sum of the largest lengths (L5, L6) measured radially of each of said outer portions (25) of said conductors (24) in contact with at least one face (181, 182) of said notch (17) is greater than a depth (L7) of said notch (17). 6. An armature according to claim 5, wherein the measurement of each length (L3, L4) of said outer portions (25) is performed in a plane (P) orthogonal to an axis (X) of said body (10), said plane ( P) intersecting the outer portion of said conductors (24) and being at a distance of less than 2 mm from an axial end face (13, 14) of said body (10), in particular said plane being in contact with a face of axial end of said body. An armature according to any one of claims 1 to 6, wherein the at least one inner portion (241 ', 242') has cross-sections having a maximum dimension measured in an ortho-radial direction (L3) greater than one dimension. measured in a radial direction (L4). 8. An armature according to any one of claims 1 to 7, said armature further comprising a retaining device (28, 34) radial of the internal portion or portions (241 ', 242') located in said notch (17). 9. An armature according to any one of claims 1 to 8, said armature consisting of a rotor (11) starter of a motor vehicle. 10. An armature according to any one of claims 1 to 8, said armature consisting of a motor vehicle alternator stator. 11. A method of producing an electric machine armature comprising a body (10) comprising at least one notch (17) formed in said body (10), said notch (17) opening axially from said body (10), said method comprising an insertion step, inside said notch (17), of at least one portion (241, 242) of a conductor (24), such that the at least one conductor portion (24) ) protrudes radially at least in part from said notch (17), and - a step of deforming said conductor portion (241, 242) so that said protruding portion is located within said notch (17) along the entire length of the notch (17). 12. The method of claim 11, wherein the deformation step comprises clamping the portion (241, 242) of conductor (24) by means of a blade (29) along at least a whole axial length of said notch ( 17). 13. The method of claim 11 or 12, said method further comprises a step of at least partial closure of said notch (17), for holding the at least one conductor (24) radially inside the notch (17). . 14. The method of claim 13, wherein said step of at least partial closure of said notch (17) comprises making tabs (28) in teeth (18) delimiting said notch (17). 15. The method of claim 14, the tabs being made by crushing the armature, in particular by crushing the sheets of the armature.