Electric rotating machine rotor

Abstract

The invention relates to an electric rotating machine rotor comprising a shaft and a plurality of teeth (24) extending radially from said shaft, each of said teeth (24) having two opposite axial faces (40, 42) substantially parallel to each other and two opposite ends; two plurality of support members (32) adapted to be referred respectively to the opposite ends of the teeth of said plurality of teeth (24), each of the support members (32) having two cylindrical surface portions (48, 50), with generating lines substantially perpendicular to said shaft and extending respectively in the continuation of said two axial faces (40, 42) of tooth converging towards each other in order to be able to form a support for a conducting wire wound around the tooth (24).Each of the two cylindrical surface portions (48, 50) has a radius of curvature that decreases as the cylindrical surface portions (48, 50) converge towards each other. Figure to be published with the abbreviation: Fig. 6.

Description

Title of the invention: Rotor of an electric rotating machine

[0001] The present invention relates to a rotor of an electric rotating machine.

[0002] One area of ​​application envisaged is in particular that of electric rotating machines for motor vehicles and more particularly, that of traction motors.

[0003] Known electric rotating machine rotors comprise a shaft and a plurality of teeth extending from the shaft, on the one hand along a radial component and on the other hand, along an axial component. The teeth are then regularly distributed around the shaft and they are separated from each other by notches. The teeth are usually made by a stack of “electrical” steel sheets.

[0004] Each of the rotor teeth has two parallel opposite faces, which define two planes which extend opposite each other relative to the axis of rotation of the rotor.

[0005] Also, each of the teeth has two opposite ends on which support members are added to receive the windings of electric wire around the teeth. Thus, the parts of the winding of electric wires which are applied at the ends to the support members are also called: "coil heads", while the support members are otherwise called: "coil head guide".

[0006] The support members have two cylindrical surface portions whose generating lines are perpendicular to the rotor shaft. The two cylindrical surface portions extend respectively in the extension of the two axial faces of the tooth and they converge towards each other. A support member is thus installed at each of the two ends of each of the teeth so as to form a support for the electrically conductive wire when it is wound around the teeth.

[0007] A challenge in this type of rotor is to be able to wind a maximum length of wire around the teeth, taking into account the space available.

[0008] Furthermore, the conductive wires are made of copper and are covered with an insulating coating so that they can be wound tightly against each other without electrical contact. And, during winding and finishing of the rotor, it is advisable not to damage the coating of the copper wires.

[0009] It turns out that during the winding of each of the teeth, bumps appear on the surface of the windings and in the vicinity of the support members.

[0010] In addition to these bosses hindering the ability to wind a maximum length of wire, they also compromise the ability to engage the shims between the windings without damaging the coating of the wires.

[0011] These shims inserted axially between the windings, aim in particular to maintain the wires in a fixed position to avoid their centrifugation during operation of the rotor inside a stator.

[0012] Also, a problem which arises and which the present invention aims to solve is to provide a rotor for an electric rotating machine in which not only the density of wound wires is maximum, but also in which the wires have not been altered during winding and assembly.

[0013] In order to solve this problem, an electric rotating machine rotor is proposed comprising: a shaft and a plurality of teeth extending radially from said shaft, each of said teeth having two opposite axial faces substantially parallel to each other and two opposite ends; two pluralities of support members adapted to be attached respectively to the opposite ends of the teeth of said plurality of teeth, each of the support members having two cylindrical surface portions with generating lines substantially perpendicular to said shaft and extending respectively in the extension of said two axial tooth faces, converging towards each other to be able to form support for a conductive wire wound around the tooth.

[0014] Also, each of said two cylindrical surface portions has a decreasing radius of curvature as said cylindrical surface portions converge towards each other.

[0015] Thus, a characteristic of the invention lies in the implementation of support members whose two cylindrical surface portions have a particular geometry with a variable radius of curvature.

[0016] Indeed, usually, the cylindrical surfaces of the support members were defined by a substantially circular directrix curve without any particular attention being paid to this geometry. In other words, the cylindrical surfaces had the profile of a portion of a cylinder with a circular base.

[0017] Also, depending on the section of the copper wires and their stiffness, bosses appeared in a more or less marked manner in the vicinity of the support members. And it was highlighted that the shape of the cylindrical surfaces conditioned the appearance of these bosses.

[0018] Thus, it appeared that by providing cylindrical surfaces whose radius of curvature decreased as they converged towards each other, the bosses disappeared.

[0019] Consequently, said density of wire wound around each tooth is optimal. And in addition, the coating of the wires is not damaged when inserting the shims.

[0020] According to a particularly advantageous embodiment of the invention, said radius of curvature decreases progressively as said cylindrical surface portions converge towards each other. Preferably, said radius of curvature varies inversely proportionally to the distance measured along said cylindrical surface portions. In other words, the directrix curve of cylindrical surfaces is related to a clothoid.

[0021] According to a preferred embodiment, said two cylindrical surface portions are symmetrical to each other with respect to a median plane intersecting said support member. In this way, the copper wires describe two parts symmetrical to each other before joining the two opposite faces of each of the teeth. It is thus easier to obtain a constant tension in the wire during winding.

[0022] Furthermore, each of the support members has two lateral edges and two substantially coplanar frontal zones, said two cylindrical surface portions extending respectively from said two lateral edges to said two frontal zones. Thus, the wire bears on the cylindrical surfaces and then in the substantially flat frontal zones without causing any bosses or winding irregularities to appear. Also, the quantity of functional wire is increased relative to the total quantity of wire wound on each of the teeth.

[0023] According to a particularly advantageous embodiment of the invention, the support members of each of said two pluralities of support members are integral with a crown, and said support members extend radially from said crown. The support members extend radially from the star-shaped crown opposite the center thereof. In this way, all the support members of the plurality of support members are integral with each other.

[0024] Preferably, the support members and said crown are molded together in a single piece of polymer material. Thus, the support members and the crown form a single piece adapted to be attached to the ends of the rotor to come into contact with the ends of the teeth.

[0025] Advantageously, said support members have a free T-shaped end. For each of the teeth, the wire is wound in a spiral in superimposed layers without loss of space. The free T-shaped end thus makes it possible to retain the wire windings of the different layers.

[0026] Thus, the teeth of said plurality of teeth equipped respectively with said two pluralities of support members, each have a winding of conductive wire, and it additionally comprises a plurality of shims inserted between the windings. These shims are inserted axially without difficulty because the teeth are devoid of bosses.

[0027] Other features and advantages of the invention will emerge from reading the description given below of a particular embodiment of the invention, given for informational purposes but not as a limitation, with reference to the appended drawings in which:

[0028] [Fig-1] is a schematic perspective view of a rotor according to the invention;

[0029] [Fig.2] is a schematic cutaway view of the object of [Fig.l] without certain elements;

[0030] [Fig.3] is a schematic detail view of an element of the object of [Fig.2];

[0031] [Fig.4] is a schematic cross-sectional view of an element of the object of the [Fig.2] ;

[0032] [Fig.5] is a schematic perspective view of a detail of the object of [Fig.3]; and,

[0033] [Fig.6] is a schematic detail view of the object of [Fig.5].

[0034] [Fig.l] shows a rotor 10 of an electric motor. It has a shaft 12 comprising two opposite ends 14, 16 intended to be mounted in rotation in the bearings of a stator not shown. The shaft 12 defines an axis of symmetry S.

[0035] The rotor 10 here comprises eight identical poles 18 extending radially from the shaft 12. Each of the poles 18 has two opposite winding heads 20, 22.

[0036] In [Fig.2] we find the rotor 10 in a cutaway view and thus a tooth 24 of one of the poles 18 appears. The tooth 24, like all those of the other poles 18, is made of a stack of “electrical” steel sheets extending transversely relative to the rotor 10.

[0037] The tooth 24 has two opposite ends 26, 28 on which are respectively attached two support members 30, 32 which will be detailed below. These support members 30, 32 are otherwise called “coil head guides”.

[0038] In addition, an electrically conductive wire 34 appears wound in a spiral around the tooth 34 and the two support members 30, 32 on four superimposed layers.

[0039] Also, [Fig.4] shows in cross-section the rotor 10 freed from its wire windings and having the single shaft 12 and eight teeth 24 extending radially from the shaft 12. The eight teeth 24 are respectively separated from each other by eight notches 36

[0040] The teeth 24 are regularly spaced from each other at an angle of 45° and they each have a free end profiled in T 38.

[0041] Also, the teeth 24 each have two opposite faces 40, 42 substantially parallel to each other. The two opposite faces 40, 42 parallel, are symmetrical to each other with respect to an axial plane containing the axis of symmetry S of the shaft 12.

[0042] Reference will now be made to [Fig. 3] showing eight support members 32 of the ends 28 of the eight teeth 24 connected together by a crown 44 from which they extend radially in a star shape. The eight support members 32 extend freely from the crown 44 opposite its center C. And they are adapted to come and bear respectively against the eight ends 28 of the eight teeth 24, while the axis of symmetry S of the rotor 12 intersects the center C of the crown 44.

[0043] Therefore, the eight support members 32 secured to the crown 44 together have a geometry identical to the cross section of the rotor illustrated in [Fig.4].

[0044] In addition, they are each surmounted by a free wing 46 forming a T. The free wing 46 then comes to bear opposite the free T-shaped end 38 of the teeth 24.

[0045] In addition, the eight other opposite support members 30 are joined together in the same way by a crown. Also, an identical part of the star-shaped part illustrated in [Fig.4] is attached to the eight other ends 26 of the eight teeth 24.

[0046] Advantageously, the star-shaped part illustrated in [Fig.4] is molded in one piece from a polymer material.

[0047] In detail in [Fig.5] we find a single support member 32 extending from the crown 44 and surmounted by the free wing 46.

[0048] Also, the support member 32 has two cylindrical surface portions 48, 50 defined by parallel generatrices G and by directing curves which will now be described with reference to [Fig.6].

[0049] Thus, we partially find on [Fig.6], the support member 32 and in detail, the two cylindrical surface portions 48, 50 defined by the generatrices G.

[0050] The support member has two lateral edges opposite each other 52, 54 and two frontal zones 56, 58 extending substantially in the same plane separated from each other by a U-shaped groove 60.

[0051] The two cylindrical surface portions 48, 50 extend respectively from their two opposite edges 52, 54 and to their two frontal zones 56, 58 converging towards each other. Also, they are symmetrical to each other with respect to the median plane Pm.

[0052] The two cylindrical surface portions 48, 50 defined by the generatrices G and also by the direction curves 62, 64 on which they rest. The direction curves 62, 64 correspond in [Fig.6] to the intersection of the two cylindrical surface portions 48, 50 with the section plane VLVI perpendicular to the generatrices G.

[0053] And a characteristic of the invention lies in the particular shape of the cylindrical surface portions 48, 50 where their directing curves 62, 64 have a radius of curvature decreasing from the two opposite edges 52, 54 respectively, to the two corresponding frontal zones 56, 58. In other words, the curvature, i.e. the inverse of the radius of curvature, increases from the two opposite edges 52, 54 respectively, to the two corresponding frontal zones 56, 58.

[0054] According to an equivalent description, it will be observed that a first osculating circle 66 in the area of ​​the cylindrical surface portions 48, 50 corresponding to the two opposite edges 52, 54 has a diameter greater than a second osculating circle 68 in the area of ​​the cylindrical surface portions located respectively in the vicinity of the two frontal areas 56, 58.

[0055] Also, it will be observed that the distance which extends between the two opposite edges 52, 54 of the support member 32, which corresponds to the diameter of the first osculating circle 66, is substantially equal to the width of the teeth 24. The width of the teeth 24 corresponds to the distance which extends between the two opposite faces 40, 42 as they appear for example, in [Fig.4], and partially represented in [Fig.6].

[0056] Therefore, the radius of curvature of the cylindrical surface portions 48, 50 in the vicinity of the two opposite edges 52, 54, is substantially equal to half the width L of tooth 24.

[0057] On the other hand, the radius of curvature of the cylindrical surface portions 48, 50 in the vicinity of the two frontal zones 56, 58 is less than half the width L of the tooth 24, and it corresponds to the radius of the second osculating circle 68.

[0058] For example, the radius of the second osculating circle 68 is between half and a quarter of the first osculating circle 66. Advantageously, the radius of the second osculating circle 68 is close to a third of that of the first osculating circle 66.

[0059] Advantageously, the radius of curvature decreases from the cylindrical surface portions 48, 50 located in the vicinity of the two opposite edges 52, 54, in a manner inversely proportional to the distance measured along said cylindrical surface portions, following the directing curves 62, 64, to the two frontal zones 56, 58.

[0060] Thus, the two cylindrical surface portions 48, 50 extend respectively in the extension of the two axial faces 40, 42 of tooth 24. And, they converge towards each other.

[0061] In this way, at each turn of the conductive wire, for the first layer of wire, the conductive wire applied taut against one 40 of the two axial faces, and parallel to the axis of symmetry S of the shaft 12, comes to bear against one 52 of the two opposite edges, then on one of the cylindrical surface portions 48, following its shape up to one 56 of the two front zones. Then the wire then joins the other 58 of the front zones to come to bear against the other cylindrical surface portion 50, following its shape up to the other 54 of the two opposite edges. Then, the wire joins the other 42 of the two axial faces to come back to bear against the other support member 30 at the other opposite end 26 of the tooth 24.

[0062] The other support member 30 is identical and therefore the wire is shaped according to the same geometry.

[0063] The other turns of wire of the first layer are made in the same way up to the free wing 46. And with regard to the turns of the other layers, the wire runs astride two contiguous turns of the lower layer to reduce the free spaces as much as possible by taking the same curvature defined by the support members 32.

[0064] Thanks to the particular geometry given to the conductive wire at the two opposite ends 26, 28 of the tooth 24, by means of the two support members 30, 32, the phenomenon of the wire being bossed around its ends 26, 28 does not appear.

[0065] The winding of the wire is thus carried out for each of the teeth 24.

[0066] Thus, the compactness of the windings is optimal and wedges of triangular section 70, 72 as illustrated in [Fig.2] can be engaged between the wire windings without damaging their coating.

Claims

Claims

1. Rotor of an electric rotating machine comprising: - a shaft (12) and a plurality of teeth (24) extending radially from said shaft, each of said teeth (24) having two opposite axial faces (40, 42) substantially parallel to each other and two opposite ends (26, 28); - two pluralities of support members (30, 32) adapted to be attached respectively to the opposite ends (26, 28) of the teeth of said plurality of teeth (24), each of the support members (30, 32) having two cylindrical surface portions (48, 50), with generating lines substantially perpendicular to said shaft (12) and extending respectively in the extension of said two axial faces (40, 42) of the tooth, converging towards each other to be able to form support for a conductive wire (34) wound around the tooth (24);characterized in that each of said two cylindrical surface portions (48, 50) has a decreasing radius of curvature as said cylindrical surface portions (48, 50) converge toward each other.;

2. Rotor according to claim 1, characterized in that said radius of curvature decreases progressively as said cylindrical surface portions (48, 50) converge towards each other.

3. Rotor according to claim 1 or 2, characterized in that said radius of curvature varies inversely proportional to the distance measured along said cylindrical surface portions (48, 50).

4. Rotor according to any one of claims 1 to 3, characterized in that said two cylindrical surface portions (48, 50) are symmetrical to each other with respect to a median plane Pm intersecting said support member (30, 32).

5. Rotor according to any one of claims 1 to 4, characterized in that each of the support members (30, 32) has two lateral edges (52, 54) and two front zones (56, 58) which are substantially coplanar, said two cylindrical surface portions (48, 50) extending respectively from said two lateral edges to said two front zones.

6. Rotor according to any one of claims 1 to 5, characterized in that the support members (30, 32) of each of said two pluralities of support members are integral with a crown (44), and in that said support members extend radially from said crown.

7. Rotor according to claim 6, characterized in that the support members (30, 32) and said crown (44) are molded together in a single piece of polymer material.

8. Rotor according to any one of claims 1 to 7, characterized in that said support members (30, 32) have a free T-shaped end (46).

9. Rotor according to any one of claims 1 to 8, characterized in that the teeth (24) of said plurality of teeth equipped respectively with said two pluralities of support members (30, 32), each have a winding of conductive wire (34), and in that it comprises a plurality of shims (70, 72) inserted between the windings.

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