Axial flux rotary electric machine

Abstract

An axial flux rotary electric machine including at least one stator and at least one rotor that are arranged along an axis of rotation of the machine, the rotor including a rotor mass and housings created in the rotor mass, the housings defining magnetic poles of the rotor, each of the housings being able to contain or not contain at least one permanent magnet.

Claims

1. An axial flux rotary electric machine, comprising at least one stator and at least one rotor that are arranged along an axis of rotation of the machine, the rotor comprising a rotor mass and receptacles created in the rotor mass, the receptacles defining magnetic poles of the rotor, each of said receptacles being able to contain or not contain at least one permanent magnet, wherein the receptacles are open toward an air gap between the rotor and the stator, and wherein the receptacles are U-shaped when viewed perpendicular to the axis of rotation of the machine.

2. The machine as claimed in claim 1, having no permanent magnets.

3. The machine as claimed in claim 1, the rotor comprising receptacles having no permanent magnets and others comprising one or more permanent magnets.

4. The machine as claimed in claim 3, in which the rotor comprises a first magnetic pole and a second magnetic pole adjacent to the first magnetic pole, the first and second magnetic poles being of different polarity, receptacles belonging to the first magnetic pole having no permanent magnets and receptacles belonging to the second magnetic pole comprising one or more permanent magnets.

5. The machine as claimed in claim 1, a magnetic pole of the rotor being defined by a receptacle or a plurality of receptacles that are cylindrical and concentric with one another.

6. The machine as claimed in claim 1, the stator comprising teeth and windings arranged on the teeth.

7. The rotary electric machine as claimed in claim 6, in which the teeth of the stator each have an essentially prismatic general shape.

8. The rotary electric machine as claimed in claim 7, comprising, in cross section considered perpendicularly to the axis of rotation of the machine, two concentric circle portions that are connected by two radii, or two linear portions connected by two radii.

9. The machine as claimed in claim 7, the teeth of the stator each bearing two windings arranged on the corresponding tooth on either side of the annular stator armature, each one of these two windings facing one of the two rotors.

10. The machine as claimed in claim 1, comprising at least two rotors arranged on either side of the stator along the axis of rotation of the machine.

11. The machine as claimed in claim 1, constituting a motor.

12. The machine as claimed in claim 1, constituting a generator.

13. The machine as claimed in claim 1, in which a magnetic pole of the rotor is defined by at least one receptacle whose general shape is a cylinder, a cylinder of revolution, conical or frustoconical.

14. The machine as claimed in claim 13, in which the general shape of the cylindrical receptacle, when observed in a plane perpendicular to the axis of rotation of the machine, is annular, circular, square, triangular, rectangular or also comprising two slots that converge toward the axis of rotation of the machine.

15. The machine as claimed in claim 13, in which a receptacle having the general shape of a cylinder of revolution comprises a bottom part.

16. An axial flux rotary electric machine, comprising: at least one stator and at least one rotor that are arranged along an axis of rotation of the machine, the rotor comprising a rotor mass and receptacles created in the rotor mass, the receptacles defining magnetic poles of the rotor, each of said receptacles being able to contain or not contain at least one permanent magnet, and one or more permanent magnets contained in one or more of the receptacles, wherein the permanent magnets are oriented radially, along a radius of the machine, or are oriented radially, along a radius of the machine and axially, perpendicular to the longitudinal axis of the machine, and wherein the receptacles are U-shaped when viewed perpendicular to the axis of rotation of the machine.

17. An axial flux rotary electric machine, comprising at least one stator and at least one rotor that are arranged along an axis of rotation of the machine, the rotor comprising a rotor mass and receptacles created in the rotor mass, the receptacles defining magnetic poles of the rotor, each of said receptacles being able to contain or not contain at least one permanent magnet, wherein a magnetic pole of the rotor is defined by at least one receptacle whose general shape is a cylinder, a cylinder of revolution, conical or frustoconical, wherein the rotor comprises receptacles having no permanent magnets and receptacles comprising one or more permanent magnets, and wherein the receptacles are U-shaped when viewed perpendicular to the axis of rotation of the machine.

Description

DETAILED DESCRIPTION

(1) The invention will be better understood from reading the following detailed description of non-limiting exemplary embodiments thereof and from studying the appended drawing, in which:

(2) FIG. 1 is a schematic and partial perspective view of a machine created in accordance with the invention,

(3) FIG. 2 is a view thereof along the arrow II,

(4) FIG. 3 is a schematic and partial detail view, along the axis of rotation X, of the stator of FIG. 1,

(5) FIG. 4 is a view similar to FIG. 2 of a variant embodiment, with a distributed-winding stator,

(6) FIG. 5 is a schematic and partial perspective view of the rotor of FIG. 1,

(7) FIG. 6 is a view thereof in section parallel to the axis of rotation X,

(8) FIG. 7 is an exploded perspective view of the magnets of a pole of the rotor,

(9) FIGS. 8a to 8c are views similar to FIG. 5, of variant embodiments,

(10) FIG. 9 is a view similar to FIG. 6 of a variant embodiment,

(11) FIGS. 10a, 10b, 11 to 13 are views similar to FIG. 5, of variant embodiments, and

(12) FIG. 14 is a view similar to FIG. 6 of another variant embodiment.

(13) FIGS. 1 to 3 and 5 to 7 show a rotary electric machine 10 according to the invention, comprising a stator 20 and two rotors 40 that are respectively arranged on either side of the stator 20 along the axis of rotation X of the machine.

(14) The stator comprises teeth 21 and windings 22 arranged on the teeth 21. As shown in particular in FIG. 2, the windings 22 are each wound around a winding axis Y parallel to the axis of rotation X of the machine.

(15) The teeth 21 of the stator 20 each comprise a face 23 facing one of the two rotors 40. The faces 23 are planar and extend perpendicular to the axis of rotation X of the machine. In the example described, the stator comprises 12 teeth, but could comprise 6 or 8, or more. The stator is symmetric with respect to a stator median plane perpendicular to the axis of rotation X of the machine. The stator 20 has no yoke.

(16) The teeth 21 are configured such that they extend beyond the windings by a distance d.

(17) The teeth 21 are bounded, when seen along the axis X, by two portions 21a and 21b which are connected by two radii 21c, as shown in FIG. 3. The windings 22 are of corresponding shape.

(18) In the example just described, the stator has concentrated winding. If this is not the case, this does not represent a departure from the scope of the present invention. The stator may for example have distributed winding, as illustrated in FIG. 4. In this exemplary embodiment, the number of teeth and notches per pole and per phase is 3.

(19) In the example described, the two rotors surrounding the stator are arranged face-to-face, not being angularly offset with respect to one another. The rotors might also be angularly offset with respect to one another, in particular in order to minimize torque fluctuations.

(20) Each one of the two rotors 40 comprises a magnetic rotor mass 41 comprising housings 42, which can receive permanent magnets 43 if these are present, and a shaft 50 extending along the axis of rotation X, on which is arranged the rotor mass 41, as illustrated in FIG. 1.

(21) Housings 42 of a rotor define a magnetic pole of the rotor. As illustrated in FIGS. 5 to 7, a magnetic pole of the rotor is defined by housings having the general shape of a cylinder of revolution, in particular three mutually concentric cylindrical housings. Each housing comprises a cylindrical part 42a and a discoidal bottom part 42b. In other words, the housing therefore has the general shape of a pot. In this case, the magnetic mass 41 of the rotor may comprise magnetic parts 41′ which are not secured to the rest of the magnetic mass, and which are arranged between the various housings of a given pole.

(22) Thus, a housing extends over a length L measured along the axis of rotation of the machine, and may have a thickness e.

(23) In the example described, all of the housings 42 are filled with permanent magnets 43, as illustrated. The permanent magnets of a magnetic pole of the rotor comprise a tubular portion 43a accommodated in the cylindrical part 42a of a housing 42, and a discoidal part 43b accommodated in the discoidal bottom part 42b of the housing 42.

(24) Each one of the rotors 40 further comprises a yoke 45 on the opposite side from the air gap.

(25) In the example which has just been described, the housings have a generally circular shape when viewed in a plane perpendicular to the axis of rotation of the machine. If this is not the case, this does not represent a departure from the scope of the present invention.

(26) The housings may for example have a different general shape when viewed in a plane perpendicular to the axis of rotation of the machine, for example square as illustrated in FIG. 8a, triangular as illustrated in FIG. 8b, or also comprising two slots that converge toward the axis of rotation of the machine as illustrated in FIG. 8c. FIG. 8c shows that the housings are U-shaped when viewed perpendicular to the axis of rotation of the machine. The Us are oriented toward the air gap.

(27) In another variant, the housings may be V shaped when viewed in a plane of section that contains the axis of rotation X, as illustrated in FIG. 9. The Vs are also oriented toward the air gap.

(28) In all of the described examples, the housings 42 are filled with permanent magnets 43. If the housings have no permanent magnets, this does not represent a departure from the scope of the present invention. By way of example, FIG. 10a shows such an exemplary embodiment in which none of the housings 42 has a magnet, and FIG. 10b shows an exemplary embodiment in which the rotor comprises a first magnetic pole and a second magnetic pole adjacent to the first magnetic pole, the first and second magnetic poles being of different polarity, housings belonging to the first magnetic pole having no permanent magnets and housings belonging to the second magnetic pole comprising one or more permanent magnets.

(29) In all of the described examples, the housings 42 are open toward the air gap. If this is not the case, and if the housings are closed on the side of the air gap by a magnetic covering portion 46 which may be formed in one piece with the rest of the magnetic rotor mass, as illustrated in FIG. 11, or attached thereto, as illustrated in FIG. 12, and held for example by adhesive bonding, this does not represent a departure from the scope of the present invention. The magnetic covering portion 46 may be made of the same material as the magnetic rotor mass, or of a different material. This magnetic covering portion then constitutes a tangential bridge, at the air gap, for the circulation of the magnetic flux.

(30) The embodiment of FIG. 13 illustrates the possibility of creating the yoke 45 of the rotor not in one piece with the magnetic mass 41, but affixed thereto, for example by adhesive bonding. A configuration of this kind permits access to the housings 42 from the outside, so as to easily insert the magnets 43 therein from the external face of the rotor.

(31) Finally, FIG. 14 illustrates the possibility of inserting, into the housings 42, wedges 48 which may for example serve to hold or separate the permanent magnets. These wedges can themselves be non-magnetic.

(32) Of course, the invention is not limited to the exemplary embodiments which have just been described.

(33) It is in particular possible to increase the number of stators or rotors.

(34) The expression “comprising a” should be understood as a synonym for “comprising at least one”.