Rotating electrical machine comprising at least one stator and at least two rotors

Abstract

The present invention relates to a rotating electrical machine including at least one stator and at least two rotors, which are arranged on either side of the stator along an axis of rotation of the machine, said at least one stator including teeth and windings arranged on the teeth, and each of said at least two rotors including two mutually coaxial rotor armatures, each bearing claw-poles arranged to interact magnetically with the teeth of the stator, the claw-poles of an armature being arranged circumferentially in alternation with the claw-poles of the other armature.

Claims

1. Rotating electrical machine comprising at least one stator and at least two rotors, which are arranged on either side of the stator along an axis of rotation of the machine, said at least one stator comprising teeth and windings arranged on the teeth, and each of said at least two rotors comprising two mutually coaxial rotor armatures, each bearing claw-poles arranged to interact magnetically with the teeth of the stator, the claw-poles of an armature being arranged circumferentially in alternation with the claw-poles of the other armature, and the magnetic flux being oriented in the air gap formed between the rotor and the stator in a direction substantially parallel to the axis of rotation of the machine, the teeth of the stator each being of generally substantially prismatic form, wherein the teeth of the stator are attached to an annular stator armature, and wherein the teeth of the stator each bear two windings arranged on the corresponding tooth on either side of the annular stator armature, each of the two windings facing one of the two rotors.

2. Rotating electrical machine according to claim 1, in which the teeth of the stator include, in cross section taken at right angles to the axis of rotation of the machine, two portions of concentric circles linked by two radii.

3. Machine according to claim 1, in which each of the rotors further comprises a toroidal excitation coil arranged between the two cylindrical and coaxial rotor armatures.

4. Machine according to claim 1, in which the excitation coil is fixed relative to the stator.

5. Machine according claim 1, in which each of the rotors further comprises a fixed ferromagnetic ring arranged so as to be passed through radially by the field winding magnetic flux.

6. Machine according to claim 1, in which each of the rotors comprises two auxiliary rotor air gaps, each of the auxiliary rotor air gaps being formed respectively between the ferromagnetic ring of said rotor and one of the cylindrical rotor armatures.

7. Machine according to claim 1, in which each of the cylindrical armatures of a rotor comprises a number of claw-poles equal to half the number of poles of the machine.

8. Machine according to claim 1, in which the two rotors surrounding the stator are angularly offset relative to one another.

9. Machine according to claim 1, comprising a shaft secured to the rotors, which rests by at least one bearing.

10. Rotating electrical machine, comprising a plurality of machines according to claim 1, each consisting of a stator and two rotors, arranged on a common axis of rotation.

11. Machine according to claim 1, comprising three machines each consisting of a stator and two rotors arranged on a common axis of rotation, in which the windings of the stators are three-phase, with one phase per stator.

12. Machine according to claim 1, forming a motor.

13. Machine according to claim 1, forming a generator.

Description

(1) The invention will be better understood on reading the following detailed description of nonlimiting exemplary embodiments thereof, and on studying the attached drawing, in which:

(2) FIG. 1 is a perspective view of a machine produced in accordance with the invention,

(3) FIGS. 2 and 3 are exploded perspective views of the machine of FIG. 1,

(4) FIG. 4 is a more detailed view,

(5) FIGS. 5 and 6 are longitudinal cross-sectional views, respectively in the compact assembled and exploded states, of the machine of FIGS. 1 to 4,

(6) FIGS. 7 and 8 are views respectively in the assembled and exploded states, of the rotating parts of the machine of FIGS. 1 to 6,

(7) FIG. 9 is an exploded view thereof in longitudinal cross section,

(8) FIGS. 10 and 11 are longitudinal cross-sectional views, respectively in the assembled and exploded states, of the fixed parts of the machine of FIGS. 1 to 9,

(9) FIG. 12 is a perspective view of the stator of the machine of FIGS. 1 to 11,

(10) FIG. 13 is an exploded view thereof,

(11) FIG. 14 illustrates a method for manufacturing teeth of the stator,

(12) FIG. 15 is a perspective view of a variant embodiment with two bearings,

(13) FIG. 16 is a view in the assembled state in longitudinal cross section,

(14) FIG. 17 is an exploded perspective view of the machine of FIGS. 15 and 16,

(15) FIG. 18 is a more detailed view thereof,

(16) FIG. 19 is a perspective view of a variant embodiment with two bearings and with central suction,

(17) FIG. 20 is a longitudinal cross section thereof,

(18) FIG. 21 is an exploded perspective view of the machine of FIGS. 19 and 20,

(19) FIG. 22 is a perspective view of a variant embodiment with two bearings, with central suction and with reinforced cohesion,

(20) FIG. 23 is a longitudinal cross section thereof, and

(21) FIG. 24 is a detail view thereof.

(22) FIGS. 1 to 13 illustrate a rotating electrical machine 10 according to the invention, comprising a stator 20 and two rotors 40, arranged respectively on either side of the stator 20 along the axis of rotation X of the machine.

(23) FIGS. 7 to 9 illustrate the rotating parts of the machine, and FIGS. 10 to 13 the fixed parts.

(24) The stator comprises teeth 21 and windings 22 arranged on the teeth 21. As may be seen notably in FIG. 11, the windings 22 are each wound around a winding axis Y parallel to the axis of rotation X of the machine.

(25) The teeth 21 of the stator 20 each comprise two half-teeth. Each half-tooth bears a winding 22. The two half-teeth are arranged on either side of an annular stator armature 24, each of the two windings facing one of the two rotors 40. The half-teeth are, for example, attached by their middle to the armature 24, for example by screwing. FIG. 13 shows the holes for the passage of the screws, oriented radially. The two half-teeth are of the same size, as are the windings that they bear. The stator is thus symmetrical relative to a median plane for the stator, at right angles to the axis of rotation X of the machine. Each winding is wound on a support 25 arranged on the corresponding half-tooth. This support 25 is preferably made of an electrically insulating material, for example plastic material. In the example described, the annular stator armature 24 is amagnetic.

(26) The teeth 21 are configured in such a way that they extend on one side of the annular stator armature 24 by a distance d, which, in the example illustrated in FIG. 13, is equal to 100% of the height h of the tooth measured along a radius of the machine. This distance d may be between 10 and 200% of the height h of the tooth. As a variant, the teeth could extend radially on either side of the annular stator armature without departing from the scope of the invention.

(27) The teeth 21 are delimited, when observed along the axis X, by two portions of concentric circles 21a and 21b linked by two radii 21c. The windings 22 are of corresponding form. The teeth 21 have two main faces 21d each facing a rotor 40. The faces 21d are planar and extend at right angles to the axis of rotation X of the machine. In the example described, the stator comprises six teeth, but could comprise 8 or 12 thereof, or even more.

(28) The teeth 21 may be formed as a stacking of plates, kept secured together by any means. The plates may be stacked along a stacking axis Z at right angles to the axis of rotation X of the machine. The cutting of the teeth 21 in the stacking of plates may be performed so as to avoid, or at least minimize, the losses. It may be performed with the teeth obtained head-to-tail, so as not to create any, or create very little, scrap, as illustrated in FIG. 14,

(29) Each of the two rotors 40 comprises two cylindrical and mutually coaxial rotor armatures 42a and 42b, each bearing claw-poles 44 arranged axially facing the teeth 21 of the stator 20, as may be seen notably in FIG. 5. The claw-poles 44 of a rotor face the teeth 21. The claw-poles 44 of a first armature 42a are arranged circumferentially in alternation with the claw-poles 44 of the second armature 42b. In other words, when moving circumferentially about the axis of rotation X of the machine, a claw-pole 44 attached to the first cylindrical rotor armature 42a of a rotor, then a claw-pole 44 attached to the second cylindrical rotor armature 42 of the same rotor, are encountered in succession.

(30) Each of the rotors 40 further comprises, as may be seen notably in FIGS. 6 and 10, a toroidal excitation coil 50 arranged between the two cylindrical and coaxial rotor armatures 42a and 42b. This excitation coil 50 makes it possible to generate a magnetic flux in the cylindrical and coaxial rotor armatures 42a and 42b and in the claw-poles 44 which face the stator 20. This excitation coil 50 is coaxial to the axis of rotation X of the machine.

(31) In the example described, the excitation coil 50 is fixed relative to the stator 20. The excitation coil is not driven in rotation, when the cylindrical rotor armatures 42a and 42b and the claw-poles 44 are so driven.

(32) Each of the rotors 40 further comprises a ferromagnetic ring 52, also fixed, arranged so as to be passed through radially by the field winding magnetic flux. The excitation coil 50 is secured to this ferromagnetic ring 52.

(33) Two auxiliary rotor air gaps 48 are formed respectively between the ferromagnetic ring 52 of the rotor and one of the cylindrical rotor armatures 42a or 42b. The magnetic flux circulating in the rotor passes through the two auxiliary rotor air gaps 48 radially. The two auxiliary rotor air gaps 48 are coaxial.

(34) In the example described, each of the cylindrical armatures of a rotor 40 comprises two claw-poles, the rotors having four poles. The number of claw-poles is equal to half the number of poles of the machine. The number of poles can, as a variant, be greater than 4. It may notably be 6 or 8, or even more.

(35) The rotors also advantageously each comprise, as may be seen notably in FIG. 8, in order to reinforce the structure of the machine, two coaxial frameworks 49a and 49b making it possible to improve the mechanical transmission and the centering on the shaft 15. One, 49a, is arranged between the two cylindrical rotor armatures 42a and 42b, being adjacent to the excitation coil 50 and takes the form of two coaxial wheels linked by portions of radii. The other, 49b, is arranged inside the inner cylindrical rotor armature 42b, that is to say between the inner cylindrical rotor armature 42b and the shaft 15 of the machine, and takes the form of two disks arranged side-by-side, each comprising two coaxial wheels linked by radii, the two adjacent disks being linked by a central ferrule 49c held on the shaft 15 between the two adjacent disks.

(36) These frameworks 49a and 49b may be non-magnetic, for example of aluminum, in order not to disturb the circulation of the magnetic flux. The outermost framework 49a, namely that arranged between the two cylindrical rotor armatures, may enable a better cohesion of the machine.

(37) The two rotors surrounding the stator are, in the example described, arranged face-to-face, being not angularly offset relative to one another. The rotors could also be angularly offset relative to one another.

(38) The machine 10 comprises a shaft 15 secured to the rotors 40, which rests by a bearing 16 on a casing 17 of the machine, notably an end flange 18 of the machine 10, that may be seen in FIG. 6.

(39) The machine also comprises, arranged on the shaft 15 opposite the end flange 18, a fan 19 housed in a ferrule 12, driven by the shaft 15. The ferrule 12 includes openings 13 allowing air, which may enter into the machine through grilles 14 formed in the end flange 18, to leave.

(40) In a variant embodiment illustrated in FIGS. 15 to 18, and as may be seen more particularly in FIG. 16, the shaft 15 rests by rolling bearings 16 on the casing 17 of the machine, and more particularly on the two end flanges 18 of the machine 10.

(41) In this particular case, the ferrule 12 housing the fan 19 is closed on the side opposite the rotors and the stator by the second end flange 18. Because of this, the machine is slightly asymmetrical, this asymmetry being due to the presence of the fan 19 on one side of the machine.

(42) In another variant embodiment illustrated in FIGS. 19 to 21, the casing 17 comprises two fans 19 arranged at each of the ends of the machine, in ferrules 12 each closed by an end flange 18. Furthermore, the casing 17 comprises openings 17a, allowing air to enter into the machine through its center, then the air to circulate inside the machine to cool it, and to leave through the openings 13 of the ferrules 12 on either side of the machine, symmetrically.

(43) In another variant embodiment, illustrated in FIGS. 22 to 24, each rotor 40 comprises drill-holes 43 passing through both the two cylindrical rotor armatures 42a and 42b and the two coaxial frameworks 49a and 49b, in order to receive amagnetic securing screws making it possible to reinforce the cohesion of the rotors 40.

(44) The operation of the machine will now be described. The current circulating in the excitation coils 50 of the rotors 40 and the rotation of the claw-poles 44 of these rotors create a magnetic flux circulating in one of the rotors then in the stator, namely in the teeth 21 thereof along an axis substantially parallel to the axis of rotation of the machine, before circulating in the second rotor situated on the other side of the stator. In a rotor, the flux circulates from the claw-poles of a given polarity, which are attached to one of the coaxial rotor armatures 42a, into this coaxial rotor armature 42a, into the ferromagnetic ring 52, before returning to the other coaxial rotor armature 42b then into the claw-poles of the other polarity, which are attached to this other coaxial rotor armature 42b.

(45) Obviously, the invention is not limited to the exemplary embodiments which have just been described.

(46) It is notably possible to multiply the number of stators.

(47) The expression comprising a should be understood to be synonymous with comprising at least one.