Claw rotor provided with an excitation winding insulator, and rotary electrical machine equipped with the claw rotor

Abstract

A claw rotor (2) provided with an insulator (11) for a field coil (10) and a rotary electric machine equipped with such a rotor, the insulator comprising a plurality of projecting petals (121, 131) intended to engage with the inner inclined periphery of a claw (9). Each of the petals (121, 131) includes: a base (122, 132) solidly connected to an associated cheek (120, 130), side edges (123, 133), and an end (124, 134). The claw-pole rotor (2) is wherein each petal (121, 131) has a thickness (e) at the side edges (123, 133) which increases from the base (122, 132) to the end (124, 134).

Claims

1. A claw rotor (202) for an electrical rotary machine having an axis of axial symmetry (X-X), comprising: two magnet wheels (7, 8) each comprising claws (9) and a flange supporting projections (19) extended by the claws (9) with axial orientation facing towards the flange of the other magnet wheel (8, 7); a core interposed between the flanges of the magnet wheels (7, 8); and an insulator (211) of an excitation winding (10) fitted on the core; the insulator (211) comprising a hub (110) fitted on the core, and a cheek (130, 120) at each of the ends of the hub (110), each cheek (120, 130) supporting a plurality of projecting petals (221, 231) which cooperate with the inclined inner periphery of the claw (9), each of the petals (221, 231) having a base (122, 132) which is integral with the cheek (120, 130), lateral edges (223, 233) and a free end (224, 234), each petal (221, 231) of the claw rotor (202) having a thickness (e) at the lateral edges (223, 233) which increases continuously from the base (122, 132) to the free end (224, 234).

2. The claw rotor according to claim 1, wherein the increase in the thickness (e) is progressive.

3. The claw rotor according to claim 1, wherein the increase in the thickness (e) between the base (122, 132) and the free end (224, 234) of each of the petals (221, 231) is between 10% and 50% of the thickness (e) of the cheek.

4. The claw rotor according to claim 1, wherein the thickness (e) at the base (122, 132) of each of the petals (221, 231) is equal to the thickness (e) of the cheek (120, 130).

5. The claw rotor according to claim 1, wherein the thickness (e) at the base (122, 132) of each of the petals (221, 231) is equal to the thickness (e) of the cheek (120, 130) plus 10%.

6. The claw rotor according to claim 1, further comprising at least one permanent magnet (38) which is fitted between two adjacent claws (9) belonging to one of the magnet wheels (7, 8).

7. A rotary electrical machine, wherein the machine is equipped with a claw rotor (2) according to claim 1.

8. The claw rotor according to claim 1, wherein the increase in the thickness (e) between the base (122, 132) and the free end (224, 234) of each of the petals (221, 231) is between 10% and 50% of the thickness (e) of the cheek (120, 130).

9. The claw rotor according to claim 2, wherein the increase in the thickness (e) between the base (122, 132) and the free end (224, 234) of each of the petals (221, 231) is between 10% and 50% of the thickness (e) of the cheek (120, 130).

10. The claw rotor according to claim 1, wherein the thickness (e) of the base (122, 132) of each of the petals (121, 131) is equal to the thickness (e) of the cheek (120, 130).

11. The claw rotor according to claim 2, wherein the thickness (e) of the base (122, 132) of each of the petals (221, 231) is equal to the thickness (e) of the cheek (120, 130).

12. The claw rotor according to claim 3, wherein the thickness (e) at the base (122, 132) of each of the petals (221, 231) is equal to the thickness (e) of the cheek (120, 130).

13. A claw rotor (202) for an electrical rotary machine, comprising: an axis of axial symmetry (X-X); two magnet wheels (7, 8) each comprising claws (9) and a flange supporting projections (19) extended by the claws (9) with axial orientation facing towards the flange of the other magnet wheel (8, 7); a core interposed between the flanges of the magnet wheels (7, 8); and an insulator (211) of an excitation winding (10) fitted on the core; the insulator (211) comprising a hub (110) fitted on the core, and a cheek (130, 120) at each of the ends of the hub (110), each cheek (120, 130) supporting a plurality of projecting petals (221, 231) which cooperate with the inclined inner periphery of the claw (9), each of the petals (221, 231) having a base (122, 132) which is integral with the cheek (120, 130), lateral edges (223, 233) and a free end (224, 234), each petal (221, 231) of the claw rotor (202) having a thickness (e) at the lateral edges (223, 233) which increases from the base (122, 132) to the free end (224, 234), the thickness (e) of each of the petals (221, 231) increases from the base (122, 132) to the free end (224, 234) at any radial cross-section of the petal (221, 231).

14. The claw rotor according to claim 13, wherein the increase in the thickness (e) is continuous.

15. The claw rotor according to claim 13, wherein the increase in the thickness (e) is progressive.

16. The claw rotor according to claim 2, wherein the thickness (e) of the base (122, 132) of each of the petals (221, 231) is equal to the thickness (e) of the cheek (120, 130).

17. A claw rotor (202) for an electrical rotary machine, comprising: an axis of axial symmetry (X-X); two magnet wheels (7, 8) each comprising claws (9) and a flange supporting projections (19) extended by the claws (9) with axial orientation facing towards the flange of the other magnet wheel (8, 7); a core interposed between the flanges of the magnet wheels (7, 8); and an insulator (211) of an excitation winding (10) fitted on the core; the insulator (211) comprising a hub (110) fitted on the core, and a cheek (130, 120) at each of the ends of the hub (110), each cheek (120, 130) supporting a plurality of projecting petals (221, 231) which cooperate with the inclined inner periphery of the claw (9), each of the petals (221, 231) having a base (122, 132) which is integral with the cheek (120, 130), lateral edges (223, 233) and a free end (224, 234), each petal (221, 231) of the claw rotor (202) having a thickness (e) at the lateral edges (223, 233) which increases from the base (122, 132) to the free end (224, 234), the thickness (e) of each of the petals (221, 231) increases from the base (122, 132) to the free end (224, 234) at any radial cross-section of the petal (221, 231); the increase in the thickness (e) between the base (122, 132) and the free end (224, 234) of each of the petals (221, 231) is between 10% and 50% of the thickness (e) of the cheek (120, 130).

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Other characteristics and advantages of the invention will become apparent from reading the following description, with reference to the accompanying figures, which illustrate:

(2) FIG. 1 is a view in axial cross-section of a rotary electrical machine according to the prior art;

(3) FIG. 2 is a view in perspective of the claw rotor in FIG. 1 equipped with permanent magnets in order to increase the power of the machine;

(4) FIG. 3 is a view in perspective of the insulator according to the prior art designed to support the winding;

(5) FIG. 4 is a view in perspective of a petal projecting from a cheek of the insulator in FIG. 3;

(6) FIG. 5 is a view in axial cross-section of a rotary electrical machine according to an invention;

(7) FIG. 6 is a view in perspective of an insulator according to the invention, which is designed to support the winding;

(8) FIG. 7 is a view in perspective of a petal according to an embodiment of the invention;

(9) FIG. 8 is a view in perspective of a petal according to a second embodiment of the invention.

(10) FIG. 9 is a view in axial cross-section of a rotary electrical machine according to another embodiment of the invention;

(11) For the sake of greater clarity, elements which are identical or similar are indicated by identical reference signs in all of the figures. In the aforementioned manner, the orientations radial, transverse and axial are to be considered relative to the axis X-X in FIG. 1.

DETAILED DESCRIPTION OF AN EMBODIMENT

(12) The electrical rotary machine of FIG. 1 according to the prior art corresponds substantially to the electrical rotary machine of the present invention of FIG. 5, and an insulator 211, which differs, will therefore be explained in detail below. In FIGS. 5 to 8, the insulator 211 has the same structure as the insulator 11 according to the prior art, i.e. it is made of electrically insulating material, in this case plastic material, and is in the form of a coil with a cylindrical sleeve 110 with axial orientation, which is provided at each of its axial ends with a cheek 120, 130 with transverse orientation, as in FIG. 1. The alternator or the alternator-starter of the invention is, as noted above, of the type indicated in the prior art.

(13) The sleeve 110 of the insulator 211 is thus fitted centered on the cylindrical core of a claw rotor 202, whereas the cheeks 120, 130 are each designed to be adjacent to, or even to come into contact with, one of the flanges of a magnet wheel.

(14) Preferably slight fitting play exists between the cheeks and the flanges of the wheels.

(15) The winding 10 is wound in this insulator 211 which acts as a support for this winding. In particular, it is supported by the tubular hub 110 with axial orientation, at the ends of which there are provided two annular cheeks 120, 130 which are perpendicular to the hub, with the annular cheeks bordering the winding laterally.

(16) In FIG. 6, the cheeks 120 and 130 each have a plurality of holes 140, whereas the sleeve 110 has a plurality of blind slots 151 which are offset circumferentially for securing, for example by means of resin or another adhesive, respectively of the cheeks 120, 130 on the flange and on the half-core of the planet wheels 8, 7 concerned.

(17) Projections 160 with axial orientation belong to the cheek 130, these projections being designed to cooperate with the base of two adjacent projections 19 of the front magnet wheel 7, for blocking in rotation of the insulator 211.

(18) It will be appreciated that this blocking in rotation is carried out as a variant as in document FR 2 612 349, with the inner periphery of the hub 110 and the outer periphery of the half-cores of the rotor 2 having a polygonal form.

(19) In addition, two lugs 112 with axial orientation are provided on the cheek 130, these lugs being designed to ensure the insulation and retention of the wire of the winding so that the latter is not in contact with the poles.

(20) In the present embodiment, the inner periphery of the hub 110 and the outer periphery of the half-cores of the rotor 202 have a circular form.

(21) Each cheek 120, 130 has projecting petals 221, 231 which, in the initial state, i.e. in the free state, are deployed and have globally radial orientation. These petals are inclined slightly axially, initially in the direction of the magnet wheel concerned.

(22) The petals 221, 231 are designed to be turned back and folded in order each to come into contact with the inner periphery of a tooth 9 of the rotor 202. The circumferential width at the base of a petal is greater than the circumferential width of the adjacent projection 19.

(23) According to the invention, the petals with a globally trapezoidal form are modified in the manner described hereinafter, in FIGS. 5 to 8.

(24) Each of the petals 221, 231 has: a base 122, 132 which is integral with the associated cheek 120, 130; lateral edges 223, 233; and a free end 224, 234.

(25) In addition, each petal 221, 231 has a thickness e at the lateral edges 223, 233 which increases from the base 122, 132 to the end 224, 234 (FIGS. 6-8).

(26) According to one embodiment (FIGS. 6 and 7), the thickness of the petals increases continuously from the base to the end at any point of its surface.

(27) The petals 221, 231 each have a thickness e at the lateral edges which is delimited by two surfaces, i.e. an inner surface Si and an outer surface Se.

(28) The inner surface Si is the one which, once the petal 221, 231 has been folded back, will face the winding 10. The surface Se is the one which, once the petal 221, 231 has been folded back, will face the claws 9.

(29) In this embodiment, the inner Si and outer Se surfaces are flat, and form between one another an angle which is contained between 0 and 10. A constant angle in this case characterizes the continuous increase of the thickness e at the lateral edges 233, which increases from the base 132 to the end 234.

(30) According to another embodiment shown in FIG. 9, the angle can vary in an increasing manner according to its distance from the base 122, 132 towards the end 124, 134 of the petal 221, 231. In this case, the increase of the thickness e at the lateral edges 233 increases progressively from the base 122, 132 towards the end 224, 234. Specially, as shown in FIG. 9, the angle .sub.2 is larger than the angle .sub.1.

(31) In this case, the angle formed between the inner Si and outer Se surfaces of a petal is the same irrespective of the radial cross-section of the petal. In other words, the thickness of a petal is constant at any point of an arc of a circle C which is concentric relative to the circular periphery of the cheek with which it is associated (see FIG. 7).

(32) The thickness e of a petal 221, 231 at the base 122, 132 is contained between the thickness e of the cheek 120, 130 and the thickness e plus 10% of the associated cheek 120, 130, and the thickness e of its lateral edges taken at its end 224, 234 is increased, this increase being contained, according to the applications and the form in the shape of a barrel of the winding 10, between 10% and 50% of the thickness e.

(33) It will be remembered that alternators for a motor vehicle have a stator outer diameter contained between 110 and 150 mm and a claw rotor outer diameter contained between 78 and 112 mm. The length of the stator body is contained between 26 and 42 mm. For good power of the alternator, this stator body has a length greater than that of the core of the claw rotor. For alternators with lower power, the length of the core of the rotor is greater than that of the stator body. The ratio of the outer diameter of the core relative to the outer diameter of the rotor is contained between 0.5 and 0.6. The thickness of the flanges of the wheels 7, 8 is less than half the length of the core of the rotor. The thickness of the claws 9 at their end for connection to the projections 19 is globally equal to the thickness of the flanges of the wheels 7, 8. For further details, reference will be made for example to document EP 0 881 756. It is apparent from the foregoing information that the thickness of the cheeks 120, 130 is as small as possible, in order to obtain a winding 10 with the longest length possible. The thickness of the cheeks 120, 130 is thus preferably less than 1 mm, for example a maximum equal to 0.8 mm. Thus, according to one embodiment, the thickness of a petal 221, 231 at its end 224, 234 can be 1 to 1.2 mm, in the knowledge that a minimum thickness is required in order to be able to bend the petals 221, 231.

(34) According to a second embodiment (FIG. 8), the thickness of the petals at the lateral edges increases continuously from the base to the end. Nevertheless, this embodiment differs from the previous embodiment in particular in that the outer surface Se of the petals comprises a recess 235. In this case, the thickness of the petals does not increase from the base to the end at all radial cross-sections of the said petal. In fact, for a radial cross-section which is localized at the recess 235, in this case the thickness increases and then decreases from the base to the end.

(35) Preferably, and as illustrated in this figure, the recess is situated in the middle of the petal, i.e. it is centered relative to the two lateral edges 223, 233.

(36) A recess of this type involves a decrease in the thickness of the petal which permits a decrease in the quantity of material used for its production, whilst providing improved insulation. In this case in particular, a thickness e1 of the petal taken at its end 234 and at the center of the petal, in this case at the recess 235, is strictly less than the thickness e of the lateral edge of the petal on its end side.

(37) In general, an area 235 of the recess 235 which is closest to the base 132 of the petal 231 has a thickness e2 greater than, or equal to, the thickness of the base of the petal. This makes it possible for the recess not to weaken the petal.

(38) A characteristic of this type, associated with the increase in the thickness of the petals at the lateral edges, makes it possible both to improve the insulation of the excitation winding, and reduce the production cost and the weight.

(39) Preferably, and as illustrated here, this recess is localized towards the end 224, 234. This also makes it possible not to weaken the petal, and in particular not to risk damaging the insulator 11 during the folding of the petals.

(40) In addition, each of these embodiments also makes it possible to insulate the winding securely when the rotor is equipped with interpolar magnets 38. There is no longer any risk of short-circuits when the magnet wheels are secured on the insulator which supports the excitation winding, in particular when the second magnet wheel is brought axially towards the first magnet wheel.

(41) It is apparent from the foregoing information that the petals 221, 231 are advantageously wider at least at their base than the axial claws 9.

(42) The invention is described in the foregoing information by way of example. It will be appreciated that persons skilled in the art will be able to produce different variant embodiments of the invention, without departing from the context of the invention.

(43) Thus, as a variant, the outer periphery of the hub is not cylindrical, for example it has a polygonal form. The same applies to the complementary inner periphery of the sleeve of the insulator.