Compact axial flux electric machine

Abstract

One aspect of the invention relates to a compact axial flux electric machine comprising a main rotary body that comprises a frame and teeth that each extend from an inner radial face of the frame, the frame further comprising a second outer radial face opposite the first inner radial face, a main stator winding located in the main stator body, comprising a first axial end facing the rotary axial end of a main rotary winding and a second axial end opposite the first axial end, a rotary power supply device comprising a rotor body and a stator body, wherein at least 50% of the axial length of the rotor body or of the stator body is positioned axially between the outer radial face of the frame of the main rotary body and the second axial end of the stator winding.

Description

DESCRIPTION TITLE: Compact axial flux electric machine TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of axial flux electric machines.

[0002] The present invention relates to an axial flux electric machine. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] The synchronous machine comprises, like any electric motor, a rotor and a stator; mainly the rotor forms the inductor and the stator forms the armature. In the state of the art, synchronous electric machine inductors are known, wound and / or with magnets. The inductor may have an advantage in being wound. Indeed, a machine with a wound iron core can produce a higher induction than those with magnets, which are also more expensive and thermally limited by their characteristics than a coil. Thus, at the same volume, a synchronous electric machine comprising a magnet inductor will be more expensive, more thermally limited and less efficient (torque), particularly at high rotation speeds, than a machine compared to an electric machine comprising a wound inductor.

[0004] There are also two main types of air gaps known in electrical machines.

[0005] A first family of synchronous electrical machine is with radial air gap, whose flux is mainly radial also called field, whose air gap volume between a stator comprising coils forming the armature and the rotor forming an inductor (magnet or wound) is cylindrical in shape surrounding the axis of rotation of the rotor.

[0006] A second family of synchronous electrical machine has an axial air gap, the flux of which is mainly axial, also called an axial field, and the air gap volume between a stator comprising coils forming the armature and the rotor forming the inductor (magnet or wound) is in the form of a disc perpendicular to the axis of rotation of the rotor.

[0007] A transverse flux family is also known, having an axial air gap part and a radial air gap part.

[0008] The advantage of the axial air gap machine is to use the maximum diameter of the machine for the air gap surface, but the larger the useful air gap diameter, the greater the torque. In addition, these machines are often chosen for reasons of axial size, which is much smaller than those of radial air gap machines, which have the advantage of radial size.

[0009] The induced stator of an axial machine comprises a stator body and a winding housed in the stator body, which can be a concentric winding, a corrugated winding, etc.

[0010] The rotor is wound and can be a salient pole or claw inductor. It consists of a rotor body tightly mounted on the rotor shaft.

[0011] Claw rotors comprise a single coil wound around the rotation axis passing through the claws formed in the rotor body. This allows for ampere turns produced by this coil passing through each pole, having the advantage of improving the conductor rate per pole and therefore increasing the torque as well as reducing joule losses. However, the disadvantage is that the claws are subjected to a concentration of deformation stress at the foot of the claws by centrifugal force, requiring a sufficiently large air gap depending on the manufacturing tolerances of the internal diameter of the armature and the external diameter of the claws. However, the larger the air gap, the lower the performance of the synchronous electrical machine. In addition, these claws have the disadvantage of having leakage fluxes not crossing the air gap, which do not contribute to the supply of torque.Finally, unlike the case of radial flux machines, a claw rotor of an axial machine will be unbalanced at the poles because the claws of a first polarity, for example North, extend from a frame of the rotor body along a radius relative to the rotor axis larger than the other claws of the second polarity, in this example South, which extend from the same frame but closer to the axis of rotation.

[0012] The salient pole rotor comprises a rotor body comprising a ferromagnetic frame and a plurality of ferromagnetic teeth angularly distributed and extending axially from the frame. The salient pole rotor further comprises one coil per tooth. Each coil is wound around one of the ferromagnetic teeth.

[0013] The rotor coil, whether in a rotor body with salient poles or claws, must be supplied with current, the machine therefore requires a power supply device. This power supply device comprises a stator part, generally comprising brushes and is fixed to a yoke of the machine surrounding and secured to the stator and the stator part faces the rotor part, for example the brushes rub on a rotating part comprising copper traces, typically called a slip ring, mounted on one end of the rotor shaft surrounded by the stator part. This device increases the axial length of the machine while it is often chosen to reduce axial size. One of the known solutions was then to manufacture power supply devices whose rotor part faces axially to the stator part to reduce the axial size.However, these power devices always increase the axial length of the electric machine.

[0014] There is therefore a need to have a synchronous electric machine architecture of a single axial flux wound inductor while allowing its axial length to be reduced without reducing the torque performance of the electric machine. SUMMARY OF THE INVENTION

[0015] The invention provides a solution to the problems mentioned above, by making it possible to incorporate at least part of the power supply device surrounded by the active part of the electrical machine (the rotor body and the stator body).

[0016] One aspect of the invention relates to a compact axial flux electric machine comprising: a rotor comprising: a rotation shaft having an axis of rotation, a main rotating body integral in rotation with the rotation shaft, made of ferromagnetic material, comprising a frame and teeth each extending from an inner radial face of the frame, the frame further comprising a second outer radial face opposite the first inner radial face, a main rotating winding located in the main rotating body, the main rotating winding comprising a first rotating axial end and a second rotating axial end opposite the first axial end, a stator comprising: a main stator body comprising an opening crossed by the rotation shaft, a main stator winding located in the main stator body and integral with the latter,comprising a first axial end facing towards the rotating axial end of the main rotating winding and a second axial end opposite the first axial end, a rotary power supply device comprising: a power rotor body secured to the rotating shaft and electrically connected to the main rotating winding to power it, a power stator body secured in rotation to the main stator body to transmit energy to the power rotor body, characterized in that the power rotor body and the power stator body each comprise an axial length and in that at least 50% of the axial length of the power rotor body or the power stator body is located axially between the outer radial face of the frame of the main rotating body and the second axial end of the stator winding.

[0017] By virtue of the invention, the incorporation of the power supply device in an area located at least largely between the axial end of the rotor frame and that of the stator winding significantly reduces the size of the axial flux electric machine. The invention makes it possible to use an area of ​​an axial flux machine that is not useful for increasing the torque of the electric machine.

[0018] Indeed, as can be seen in Figure 2, using an axial flux machine with an internal radius noted r1 in Figure 2, from the rotor body to the coil equal to 60% of the external radius noted r2, from the rotor body to the coil allows to have the maximum torque of the electric machine. Thus there is a free zone between the internal radius and the radius of the rotation shaft of the machine. Using this zone to house at least a large part of the power supply device by mainly surrounding its rotor or stator body with the main stator body and / or the stator, allows to reduce its axial size and therefore to reduce or even not increase the total axial length of the electric machine.Of course, some machines with radii of several meters can have a ratio lower than 40% and have enough space for the insertion of the power supply device in this free zone between these two axial ends (frame and stator winding).

[0019] In addition to the characteristics which have just been mentioned in the preceding paragraph, the electrical machine according to one aspect of the invention may have one or more additional characteristics among those in the following paragraphs, considered individually or according to all technically possible combinations.

[0020] According to one embodiment, the power rotor body and the power stator body each comprise an axial length and in that at least 50% of the axial length of the power rotor body or the power stator body is located axially between the second axial end of the rotor winding and the second axial end of the stator winding.

[0021] According to one embodiment, the power rotor body has 100% of its axial length located axially between the second outer radial face and the second axial end of the stator winding. According to one example, the power rotor body has 100% of its axial length located axially between the second outer radial face and the first axial end of the stator winding and in that at least 50% of the supply stator body is located axially between the first end of the rotor winding and the second axial end of the stator winding.

[0022] According to one embodiment, the rotating body further comprises: a first radial rotor axial air gap face, a second radial rotor axial end face, opposite the first radial rotor axial air gap face, the stator body further comprises: a first radial stator axial air gap face facing the first radial rotor axial end face, a second radial stator axial end face opposite the first radial stator axial air gap face, teeth each comprising a fixed air gap surface forming a portion of the first radial stator axial air gap face axially opposite the first rotor air gap face, an opening surrounding the rotation shaft, centered on the axis of rotation, axially opposite the first rotor air gap face,and the axis of rotation extending from the first radial face of the stator axial end to the second radial face of the stator axial end, the power supply device being 100% located axially between the second radial face of the stator axial end and the second radial face of the rotor axial end. This embodiment makes it possible to house the power supply device without it influencing the axial length of the electrical machine.,

[0023] According to one embodiment, the rotor comprising an internal radius measured between the axis of rotation and an internal radial end of the main rotor body located axially closest to the axial air gap and radially closest to the axis of rotation and an external radius measured between the axis of rotation and an external radial end of the main rotating body located axially closest to the axial air gap and radially furthest from the axis of rotation, and in that the internal radius is between 40% and 80% of the external radius: the fact of being in excess of 40% makes it possible to have sufficient space radially between the coil bodies at the level of the coils and the rotor shaft to house the power supply device. That this either a claw rotor, or a salient pole rotor or a smooth pole rotor, each tooth comprises a base extending from the frame axially to a tip of the tooth, the tip comprises a radial axial air gap surface and in that the internal radius is measured at the edge of the tip closest to the axis of rotation and the external radius at an edge of the tip furthest from the axis of rotation.

[0024] According to one embodiment, the power supply rotor body is axially opposite the power supply stator body. This makes it possible to use the cylindrical space available between the rotor and the stator having a diameter greater than the axial length.

[0025] According to an example of a combination of these last two embodiments: the power rotor body comprises a rotary power outer radius less than or equal to the inner radius and comprises a first and a second rotary power axial end face axially opposite each other, the power stator body comprises a rotary power outer radius less than or equal to the inner radius and comprises a first and a second rotary power stator axial end face axially opposite each other, the first rotary power axial end face and the first rotary power stator axial end face face each other and are each located between the second axial end of the rotary winding and the second axial end of the stator winding.

[0026] According to a variant of the previous embodiment, the power supply rotor body is surrounded by at least one air gap formed between a first rotary air gap face of the rotor and a first stator air gap face of the stator.

[0027] According to one embodiment, the main rotating body is integral with the rotating shaft via the feed rotor body. This allows the feed rotor body as a connecting means and thus to reduce the weight, furthermore this can allow to use all the available space formed inside the main rotating body.

[0028] According to one embodiment, the axial flux electric machine comprises a bearing between the power stator body and the rotation shaft. This makes it possible to better support the rotation shaft.

[0029] According to one embodiment, the rotary power supply device is brush-type, the power supply rotor body comprises a first track and the rotary power supply device comprises a second track secured to the rotor, the first and second tracks each being connected to the main rotary winding to supply it electrically and the power supply stator body comprising at least a first and second group of brushes in contact with the first and second track respectively. The tracks can be, for example, rings or washers, for example made of copper, each connected to a winding of the rotor.

[0030] According to an example of this embodiment, the rotor is supported by the stator by the first track and the brushes of the first group of brushes at least on one side of the rotor shaft. This makes it possible to use the brushes as bearings and therefore to reduce the manufacturing cost and the weight of the electrical machine. The rotor can in particular on this side or entirely be supported by the stator only by tracks and brushes of the brush device.

[0031] According to one option of this example: the first track has a ring shape comprising a revolution connection surface, the first group of brushes of the power supply stator body comprises at least a first brush in contact with the revolution connection surface and a second brush aligned with the second brush radially opposite the first brush, the second being in contact with the same revolution connection surface, the power supply stator body comprising at least a first and second spring each exerting a radial force on the first brush and the second brush respectively against the first track,wherein the rotating support between the rotor and the stator in the opening is formed solely by the power supply device including at least the first track in contact with the first and second brushes on the side of the first axial end and at least two other brushes of the first or second group of the power supply device, the other brushes being aligned at 90° relative to the alignment of the first and second brushes.,

[0032] According to an example of this embodiment, the only bearing or bearings between the rotor and the stator is formed by the brushes and tracks of the power supply device.

[0033] According to an option of one of the previous examples, the rotor is axially supported by the second track and the brushes of the second brush group on the other side. This makes it possible to use the brushes and the track as bearings and therefore reduce the manufacturing cost and the weight of the electric machine. In this example, the electric machine can be without an additional bearing between the rotor and the stator.

[0034] According to a variation of this option of this example of this first embodiment, the second track comprises a radial surface and the rotary feeder comprises springs exerting an axial force on the brushes of the second brush group against the radial surface. This makes it possible to eliminate (counter) the axial force of the magnetic field between the rotor and the stator.

[0035] According to an option of this example, the first and second brushes of the second group are oriented at 90° relative to those of the first group. For example, the first and second brushes are aligned and oriented at 90° as in the option preceding the variant or are oriented axially against the second track (i.e. 90° relative to the radial orientation of the brushes against the first track as in the previous variant).

[0036] According to an option of this example the first and second brush groups each comprise a third brush and a fourth brush aligned together at 90° relative to the alignment of the first and second brushes. Each brush is urged towards the corresponding track radially by a spring. The device may comprise one spring per brush or one spring for two brushes.

[0037] According to a variant of this embodiment, the rotary power supply device is inductive, the power supply stator body comprising an induction circuit and the power supply rotor body comprising an induced coil opposite the induction circuit to transform the energy of the induction circuit into electric current, and electronic components to rectify the electric current transformed by the induced coil, connected to the main rotary winding to power it. This makes it possible to reduce friction compared to the previous embodiment.

[0038] According to one example, the power rotor body comprises an electronic printed board comprising the electronic components.

[0039] According to an example of this embodiment: the rotary power supply device is inductive, comprising: a second power supply rotor body, a second main rotary body secured to the second power supply rotor body, a second main coil wound in the second main rotary body, and in which the main stator body and the main stator winding are located between the two main rotating bodies and the power stator body secured to the main stator body is located between the two power rotor bodies. This makes it possible to balance the axial forces and therefore increase the efficiency of the machine and reduce wear on the bearings.

[0040] According to one example, the machine comprises a printed board comprising: the main stator body, the stator winding formed by traces etched on the printed board and the power stator body located between the two power rotor bodies, the power stator winding formed by traces etched on the printed board. This makes it possible to have an axial flux machine that is easy to manufacture and also takes up little space axially.

[0041] According to a variant of these last two embodiments, the rotary feed device is capacitive.

[0042] According to one embodiment, the power supply device further comprises a second power rotor body, the power stator body being located between the first and second power rotor bodies to power them. This allows axial forces between the rotor bodies and the stator body of the power supply device to be balanced.

[0043] According to one embodiment, the power supply device further comprises a second power rotor body, the power stator body being located between the first and second power rotor bodies to power them. This allows axial forces between the stator bodies and the rotor body to be balanced.

[0044] According to one embodiment, the power supply device further comprises a second power stator body, the power rotor body being located between the first and second power stator bodies to power them. This makes it possible to balance the axial forces between the stator bodies and the rotor body.

[0045] According to one embodiment, the main rotating body comprises an opening housing the rotating shaft, the opening having a diameter equal to + or - 5% of the diameter of the opening of the main stator body. This makes it possible to reduce the weight of the main rotor.

[0046] According to one embodiment, the main rotor body comprises teeth comprising at least one radial air gap surface forming a portion of a first radial face of the rotor axial air gap, the rotor further comprises a hoop surrounding and in contact with the teeth of the rotor body.

[0047] According to an example of this embodiment, the hoop comprises walls forming a housing receiving a portion of the winding, the housing having a diameter external to the diameter of the teeth of the rotating body. This makes it possible to make the hoop in one piece with the winding and thus reduce the number of parts.

[0048] According to one example, the rotating body of the power supply device comprises a base fitted onto the rotor shaft and a shell extending from the base, the shell being integral with the rotating ferromagnetic body and forming a housing complementary to the housing of the hoop to receive a portion of the winding.

[0049] According to one embodiment, the main rotating body has a salient pole comprising a plurality of teeth each forming a north or south pole, the main rotating winding comprising a plurality of coils powered and electrically connected to the power supply rotor body, this makes it possible to have the advantages of a salient pole machine stated previously.

[0050] According to a variant of this embodiment, the main rotating body is claw-shaped, in which the teeth each form a north or south pole and each comprise a base extending axially from the base of the ferromagnetic frame and a beak extending radially from the base, the teeth forming either internal claws whose base extends from an internal periphery of the frame on the side of the orifice or external claws whose base extends from the side of an external periphery of the frame opposite the orifice. This makes it possible to increase or improve the conductor rate per pole and therefore increase the torque as well as to reduce joule losses while having an anti-deformation means for maintaining the claws.

[0051] According to one example, the rotor comprises a second main rotating body integral in rotation with the rotation shaft, identical to that of the first main rotating body and a second main rotating winding wound in the second main rotating body, the first and second main rotating bodies each comprising a plurality of teeth each forming a north or south pole, the power rotating body being connected to the first and second rotating windings such that each tooth forming a pole of the second rotating body is axially aligned with a tooth of the first rotating body having a pole of a different polarity from the first body, the main stator body being located axially between the two main rotating bodies and in that each tooth comprises a second air gap surface opposite the first air gap surface and in that the second air gap surface is located opposite the second main rotating body.

[0052] According to one embodiment, the machine comprises: a second main rotating body identical to the first main rotating body comprising a second rotating winding, a main stator body located axially between the two main rotating bodies, in which: the frame of the main stator body comprises a static shaft comprising the opening housing the rotation shaft connecting the two rotary power supply bodies, the static shaft comprising the brush groups of the power supply device and The power supply device comprises a ring per brush group comprising a surface of revolution housed in the rotation shaft surrounded by the corresponding brush group, each ring forming a track connected to the two windings or to one of the two windings of the first and second main rotating bodies, in which: at least one ring and one group of brushes are located axially between the rotating frame of the first main rotor body and a radial central plane passing through the stator body, at least one ring and one group of brushes are located axially between the rotating frame of the second main rotor body and the radial central plane passing through the stator body.

[0053] In one example, the rotor is supported by the stator solely through the contact between the brushes of a brush group and the surface of revolution of the ring. Thus, the electric machine is without a bearing between the rotor and the stator, thus saving weight and making it more compact.

[0054] Optionally, the first rotor winding is powered by a first and second group of brushes and a first and second ring located axially between the rotating frame of the first main rotor body and the radial central plane passing through the stator body and the second rotor winding is powered by a third and fourth group of brushes and a third and fourth ring located axially between the rotating frame of the second main rotor body and the radial central plane passing through the stator body.

[0055] The different options of the number of brushes and springs of the embodiment whose device is a brush described previously can be applied to this embodiment.

[0056] According to one embodiment, the stator comprises a second main stator body identical and integral in rotation with the first main stator body and the power supply stator body, and a second main stator winding wound in the second main stator body, the first and second main stator bodies each comprising a plurality of teeth each forming a north or south pole, the main rotating body being located axially between the two main stator bodies and in that the frame comprises several angular sections and the second external radial face of the frame forms on each section a second air gap surface opposite the first air gap surface and in that the second air gap surface is located opposite the second main stator body.

[0057] According to an example of this embodiment and of the embodiment whose power supply device is brushed, the rotary brushed power supply device comprises: a second power stator body housed in the frame of the second main stator body, comprising the second group of brushes and a second power rotor body comprising a ring comprising a surface of revolution housed in the rotation shaft axially opposite the first rotor body housed in the rotation shaft.

[0058] Optionally, the first and second stator power supply bodies respectively comprise a third and fourth brush group and the first and second rotor bodies respectively comprise a third ring forming a third track and a fourth ring forming a third track, the rings of the first and second bodies respectively supplying the first and second windings of the main body wound around the teeth respectively forming the first and second air gap surfaces.

[0059] These last two embodiments each allow axial forces to be balanced.

[0060] In particular in these last two embodiments, the use of a feeding device respectively with a double rotary feeding body or with a double body stator power supply each described previously in an embodiment, is particularly interesting, both in terms of size and in terms of distribution of forces and electrical energy.

[0061] According to one embodiment, the rotor further comprises inter-tooth-base magnets between each tooth.

[0062] According to one embodiment, the rotor further comprises inter-pole magnets between each tooth.

[0063] These two previous embodiments each allow to increase the magnetic saturation level of the claw and therefore to have a higher inductive current before saturation and therefore the possibility of having more torque. That is to say that a claw without a magnet will be magnetically saturated more quickly than the same claw with a magnet.

[0064] According to another unclaimed innovation, an axial flux electric machine with claws comprises: a stator comprising a winding and teeth comprising a radial axial air gap surface and a claw rotor comprising an axis of rotation and a ferromagnetic body comprising a frame and teeth each extending from the frame in a claw shape, each tooth comprising: a base extending axially from an inner face of the frame and a nose extending radially from an end of the base opposite the frame to a free end of the nose, forming a radial axial air gap surface between its free end and its end extending from the base, located axially opposite the radial axial air gap surface,in which every other tooth has its beak extending from its base towards the axis of rotation to its free end, each forming an external claw and the other teeth have its beak extending radially from its base towards the outside opposite the axis of rotation, each forming an internal claw, characterized in that the rotor comprises inter-pole magnets each mounted between two beaks of an internal claw and an external claw and / or inter-frame-beak magnets each mounted between a free end of a beak and the frame., In one example the machine includes a hoop surrounding the beaks of the internal and external claws. According to one example, the machine comprises a power supply device according to the invention described above or a power supply device comprising its rotary part mounted on the rotation shaft outside the rotor and the stator and its stator part mounted against the stator or a yoke for example, axially opposite the stator.

[0065] Another unclaimed invention relates to a compact axial flux electric machine comprising: a rotor comprising: a main rotating body made of ferromagnetic material, comprising a frame and teeth each extending from an inner radial face of the frame, the frame further comprising a second outer radial face opposite the first inner radial face, a main rotating winding located in the main rotating body, the main rotating winding comprising a first rotating axial end and a second rotating axial end opposite the first axial end, a stator comprising: a main stator body comprising a frame and ferromagnetic teeth each extending from an inner radial face of the frame, a main stator winding located in the main stator body and integral with the latter,comprising a first axial end facing towards the rotary axial end of the main rotary winding and a second axial end opposite the first axial end facing the frame, a rotary power supply device comprising: a rotor power supply body integral with comprising at least a first and second track, each electrically connected to the main rotary winding to power it, at least the first track is in the form of a ring comprising a connection surface of revolution, a power supply stator body integral in rotation with the main stator body comprising: -at least a first and second group of brushes in contact with the first and second track respectively, in which the first group of brushes of the power supply stator body comprises at least a first brush in contact with the connection surface of revolution and a second brush radially opposite the first brush in contact with the same connection surface of revolution to transmit the electrical energy to the power supply rotor body, -at least one first and second spring each exerting a radial force on the first brush and the second brush respectively against the first track to transmit the energy to the supply rotor body, characterized in that the rotating support between the rotor and the stator is formed at least on one axial side by the first track and the first and second brush together forming a bearing between the rotor and the stator guiding the rotor in rotation relative to the stator.

[0066] According to one embodiment, wherein the stator is a central stator comprising further teeth extending axially from another radial surface of the stator frame opposite the inner radial face of the frame, and another stator winding around the teeth, the machine comprising a second rotor axially facing the other teeth of the stator, the stator comprising a shaft comprising a portion passing through a first opening of the first rotor and a second portion passing through a second opening of the second rotor, the device for supplying the first rotor being located in the first opening of the first rotor, the machine comprising another device for supplying the second rotor located in the second opening of the second rotor.

[0067] According to different embodiments, the electric machine is according to one of the examples of the embodiment of the claimed invention in which the rotary power supply device is brush-type.

[0068] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0069] The figures are presented for information purposes only and in no way limit the invention.

[0070] [Fig. 1] represents a schematic diagram of an electrical machine with salient poles according to a first embodiment.

[0071] [Fig. 2] represents a curve representing the torque ratio versus ratios of internal and external diameters of the active parts of a main rotor or stator of an axial flux electric machine

[0072] [Fig. 3a] represents a schematic diagram of an electric claw machine according to a second embodiment.

[0073] [Fig. 3b] represents a schematic diagram according to another view of the electric claw machine according to the second embodiment.

[0074] [Fig. 4a] schematically represents a third embodiment according to an axial section of an axial flux electric machine.

[0075] [Fig. 4b] schematically represents a section AA of figure 4a.

[0076] [Fig. 5a] schematically represents a fourth embodiment according to an axial section of an axial flux electric machine.

[0077] [Fig. 5b] schematically represents a section AA of figure 5a.

[0078] [Fig. 6a] schematically represents a fifth embodiment according to an axial section of an axial flux electric machine.

[0079] [Fig. 6b] schematically represents a section AA of figure 6a.

[0080] [Fig. 7a] schematically represents a sixth embodiment according to an axial section of an axial flux electric machine.

[0081] [Fig. 7b] schematically represents a section AA of figure 7a.

[0082] [Fig. 8a] schematically represents a seventh embodiment according to an axial section of an axial flux electric machine.

[0083] [Fig. 8b] schematically represents a section AA of figure 8a.

[0084] [Fig. 9a] schematically represents a ninth embodiment according to an axial section of an axial flux electric machine.

[0085] [Fig. 9b] schematically represents a section AA of figure 9a.

[0086] [Fig. 10] schematically represents an axial section of an induction power supply device of an axial flux electric machine according to an example of one of the embodiments.

[0087] [Fig. 11] schematically represents an axial section of an induction power supply device of an axial flux electric machine according to an example of a second embodiment.

[0088] [Fig. 12] schematically represents an axial section of an induction power supply device of an axial flux electric machine according to an example of a third embodiment.

[0089] [Fig. 13] schematically represents an axial flux electric machine according to a ninth embodiment.

[0090] [Fig. 14] schematically represents a rotor of an axial flux electric machine according to the ninth embodiment.

[0091] [Fig. 15] schematically represents an axial section of an axial flux electric machine according to a tenth embodiment.

[0092] [Fig.16] schematically represents an axial section of an axial flux electric machine according to an eleventh embodiment.

[0093] [Fig.17] schematically represents an axial section of an axial flux electric machine according to a twelfth embodiment.

[0094] [Fig.18] schematically represents an axial section of an axial flux electric machine according to a thirteenth embodiment.

[0095] [Fig.19] schematically represents an axial section of an axial flux electric machine according to an unclaimed invention. DETAILED DESCRIPTION

[0096] The figures are presented for information purposes only and in no way limit the invention.

[0097] [Fig. 1] shows a schematic representation of principle according to a three-dimensional view of an example of an axial flux electric machine according to a first embodiment.

[0098] The axial flux electric machine comprises a rotor 1 comprising a rotation shaft 11 with an axis of rotation X, a main rotating body 12 rotationally fixed to the rotation shaft 11 and a main rotating winding 13 located in the main rotating body 12. The main rotating body 12 is ferromagnetic and comprises a rotating frame 121 in the form of a ferromagnetic crown and ferromagnetic teeth 120 each extending axially of an inner radial surface of the rotary frame 121 and each comprise an axial air gap radial surface axially opposite the rotary frame 121.

[0099] In this embodiment, the teeth 120 are each a salient pole each comprising a central portion extending axially from the internal radial surface of the rotary frame 121 and a beak extending axially from the central portion and projecting circumferentially on either side. The beak therefore comprises the radial surface of the axial air gap. The main rotary winding 12 may be concentric or distributed, in this case it is concentric and comprises a coil 130 per salient pole (of which only two are referenced) but could also have a concentric winding having a coil on 2 salient poles.

[0100] The axial flux electric machine further comprises a stator 2 comprising a main stator body 21 comprising a central opening 21 o crossed by the rotation shaft 1 1 .

[0101] The stator further comprises a main stator winding 23 located in the main stator body 21 and secured to the latter.

[0102] The main stator body 21 is in this embodiment also ferromagnetic and comprises a ferromagnetic stator frame 21 1 and teeth 210 also forming salient poles extending from an inner radial surface of the stator frame 211 . The teeth 210 have the same shape as that of the main rotating body 1 1 (central part and beak) but do not have the same dimension. In this case, in this example the main stator body 21 comprises fewer teeth 21 than the number of teeth 120 of the main rotating body 12. The radial axial air gap surfaces of the teeth 210 of the main stator body 21 face the teeth 120 of the main rotating body 12 delimiting between them an axial air gap, in other words the axial air gap is delimited axially between the radial axial air gap surfaces of the tips of the teeth of the main stator body 21 and of the main rotating body 12.

[0103] The main stator winding 23 may be concentric or distributed, in this case it is concentric and comprises a coil 230 per salient pole but could also have a concentric winding having a coil on 2 salient poles. The main stator body 21 may also be, according to another example, made of a non-magnetic or paramagnetic material, for example resin and fiberglass or even a PCB type electronic card comprising conductive active parts (for example etched copper layer) each forming the concentric type coil.

[0104] The main rotary winding 13 and the main stator winding 23 each comprise a first and second axial end opposite each other, called the first rotary axial end 13a and a second rotary axial end 13b for the main rotary winding 13 and are called a first axial end 23a and a second axial end 23b for the main stator winding 23. The first rotary axial ends 13a and stator 23a are the ends closest to the axial air gap. In this embodiment, both the main rotary and stator windings 13, 23 being concentric windings, at least one coil comprises the first axial end 13a, 23a and at least one other coil (or the same) comprises the second axial end 13b, 23b.

[0105] The frames 121 and 211 of the main rotating and stator bodies each have in this example a washer shape and extend axially between an external radial face and the internal radial face.

[0106] The electrical machine further comprises a rotary power supply device C comprising a power supply rotor body C1 secured to the rotation shaft 11 and electrically connected to the main rotary winding 13 to power it. The electrical machine thus further comprises conductors (not shown) connecting the power supply rotor body C1 to the main rotary winding 13 (which may be a continuity of a conductor forming the main rotary winding 13 or a coil of the power supply rotor body C1.

[0107] The rotary power supply device C further comprises a power supply stator body C2 rotationally secured to the main stator body 21 to transmit energy to the power supply rotor body C1. The mechanical connection between the power supply stator body C2 and the main stator body 21 is not shown but may for example be arms extending radially between them in the central opening 21 o or a plate 43 closing the central opening 21 o.

[0108] In this example, the power stator body C2 surrounds the power rotor body C1. In this example, the stator body C2 comprises brushes and the power rotor body C1 comprises a commutator with blades for powering the power coils of the main rotating winding 13.

[0109] The power rotor body C1 comprises an axial length 11 and the power stator body C2 has an axial length I2 which are not referenced in this figure 1. By the axial length 11 of the power rotor body C1 or the axial length I2 of the power stator body C2, is meant respectively the maximum length of the rotary and stator parts of the power device C necessary for the transmission of electrical energy from one to the other. At least 50% of the axial length 11 or I2 of the power rotor body C1 or the power stator body C2 is located axially between the second external radial face 12b of the frame 121 of the main rotary body 12 and the second axial end 23b of the stator winding 23.

[0110] Here in this example the two axial lengths 11 and 12 are equal. In this example, the power supply rotor body C1 and the power supply stator body C2 are each surrounded by the rotor 1 and the stator 2 such that they are each located axially between the two outer radial faces of the stator 211 and rotor 121 frames. In other words the length between the outer radial face of the rotor 121 frame and the outer radial face of the stator 211 frame is longer than each of the two axial lengths 11 and 12. In other words, the power supply device C is entirely located axially between these outer radial faces of the stator 211 and rotor 121 frames. In this case the power supply device is surrounded by the two stator 211 and rotor 121 frames and by the axial air gap between the rotor 1 and the stator 2.In this example, the largest radius R4 of the power supply stator body C2 (the largest radius therefore of the power supply device) is less than the internal radius R2 of the main rotating body 12 measured at the level of the tip of the tooth 120 closest to the x axis (i.e. the smallest radius of the rotating body 12 measured at the level of the tips of the teeth 120).

[0111] Thus in this example the power supply device C does not take up any axial space. In addition, the internal radius R2 is between 40 and 80% (here 60%) of an external radius R1 of the main rotating body 12 measured at the level of the tip of a tooth furthest from the X axis (i.e. the largest radius of the rotating body 12 measured at the level of the tips of the teeth 120). As can be seen in Figure 2, this ratio allows for the best torque efficiency.

[0112] More precisely, in this example at least 50% (in this case 80%) along the axial length 11, 12 of the power supply rotor body C1 or of the power supply stator body C2 (in this case both bodies) is located axially between the second axial end 13b of the rotary winding 13 and the second axial end 23b of the stator winding 23. Thus the volume of the power supply device is located in a free location without affecting the axial length of the machine and without reducing the efficiency of the axial flux electric machine.

[0113] Figures 3a and 3b each schematically represent a three-dimensional view of an example of an axial flux electric machine according to a second embodiment identical to the example of the first embodiment except that the rotor 1 is different and the power supply device C is different.

[0114] In this example, the rotor 1 is claw-shaped and not salient-pole as in the first example of the first embodiment, in other words the main rotating body 12 is different in that the teeth 120 have a claw shape and in that the winding 13 is a single coil wound between the claws. Every other tooth 120 is an external claw 120e comprising a base extending axially from the inner face of the frame 121 to the radial level of the outer radius R1 and the other teeth are internal claws 120i extending of the inner face of the frame 121 at the radial level of the inner radius R2. As can be seen, the inner and outer claws are angularly alternated. The outer claws 120e each comprise a beak extending radially from the base towards the axis of rotation and the inner claws 120i each comprise a beak extending radially from the base outwards opposite the axis of rotation X.

[0115] In this second embodiment, the power supply device C is different in that the power supply rotor body C1 is located axially opposite the power supply stator body C2. The power supply device C can always be brushed or can be capacitive or even inductive, in the latter case, the power supply device C can be like that shown in section figure 1 1 explained below.

[0116] In Figure 3a, the power rotor body C1 can be seen surrounded by the main rotating body 12 and the rotating winding 13 of the rotor 1 and in Figure 3b, the power stator body C2 can be seen surrounded by the main stator body 21 and the rotating winding 23 of the stator 2.

[0117] In this example, the main rotating body 12 is coupled to the rotation shaft 11 via the power rotor body C1. The mechanical connection between the power rotor body C1 and the main rotating body 12 is not shown. For example, arms forming spokes connecting the two bodies can be produced. According to another example, the power rotor body C1 can be mounted tightly in the main rotating body 12 (in the latter case an external radius R3 of the power rotor body C1 would be equal to the internal radius R2 of the main rotating body 12).

[0118] As in Figure 1 of the previous embodiment, the mechanical connection between the power supply stator body C2 and the main stator body 21 is not shown, but may for example be arms extending radially between them in the central opening 21 o or a plate 43 closing the central opening.

[0119] The electrical machine further comprises here a bearing P1 (a ring) mounted in the power supply stator body C2 surrounding the rotor shaft 11 to support it and allow its rotation along the X axis.

[0120] In this embodiment, the power supply device C is located between the two surfaces between at least 50% along the axial length 11, 12 of the power supply rotor body C1 or of the power supply stator body C2 is located axially between the second axial end 13b of the rotary winding 13 and the second axial end 23b of the stator winding 23.

[0121] This feed device C can also be mounted in place of that of the machine of the first embodiment and vice versa.

[0122] Other embodiments will now be described, the rotor 1 can be represented with claws or with salient poles as in the first or second embodiment and can also be replaced by one or the other.

[0123] Figure 4a represents a schematic diagram according to an axial section (comprising the axis of rotation) of an electric machine according to a third embodiment and Figure 4b a section AA of the machine at the level of the beaks of the teeth 120 of the main rotating body 12.

[0124] This electrical machine is identical to that of the second embodiment except that the rotor has salient poles as in the first embodiment and that the frame 121 is coupled to the rotor shaft 11. Thus in this example, the power rotor body C1 is mounted axially between the frame 121 and the power stator body C2 while being surrounded by the teeth 120, the axial air gap and the teeth 211. Furthermore, the axial length dimension 11 of the power rotor body C1 is shown between a first end C1a and a second end C1b. As can be seen, here the power supply rotor body C1 is located axially (according to its length 11 to 100%) between the second axial end 13b of the rotary winding 13 and the second axial end 23b of the stator winding 23. An empty space is located axially between the internal radial face of the frame 121 and the second axial end of the power supply rotor body C1.Thus, the feed device C could also, according to another example, be moved axially towards this internal radial face of the frame 121.

[0125] The axial length I2 of the power stator body C2 is also shown between a first end C2a and a second end C2b. Here in this example only 50% of the axial length I2 of the power stator body C2 is located axially between the second axial end 13b of the rotating winding (13) and the second axial end 23b of the stator winding 23.

[0126] Finally, the electrical machine comprises in this example a closing plate 43 partially closing the central opening and making it possible to fix the power supply stator body C2 to the main stator body 21 by being pressed against its second axial end radial face 21b and against the second end C2b of the power supply stator body C. The fixing of the plate 43 can be done by gluing or by screwing or by welding, or by crimping or any other fixing means. The electrical machine further comprises a bearing P1 between the rotor shaft 11 and the power supply stator body C2 allowing the rotational connection between them.

[0127] Figure 5a represents a schematic diagram according to an axial section (including the axis of rotation) of an electric machine according to a fourth mode of embodiment and figure 5b a section AA of the machine at the level of the beaks of the teeth 120 of the main rotating body 12.

[0128] This electrical machine is identical to that of the second embodiment except that the power supply device C comprises a second power supply rotor body C1', the power supply stator body C2 being located axially between the first and second power supply rotor bodies C1, C1'. In the case of a brush power supply device C, the power supply stator body C2 comprises brushes extending on either side of a brush support plate. In the case of an inductive power supply device C, the power supply device C may be like that shown in section in Figure 11 explained below.

[0129] The machine may comprise an electrical conductor in a groove or on the shaft 11 connecting the second power rotor body C1' to the coil 13 to supply it in parallel with the power rotor body C1.

[0130] Figure 6a represents a schematic diagram according to an axial section (comprising the axis of rotation) of an electric machine according to a fifth embodiment and Figure 6b a section AA of the machine at the level of the beaks of the teeth 120 of the main rotating body 12.

[0131] This electrical machine is identical to that of the third embodiment except for the following elements: the main rotating body 12 is claw-type (as in the second embodiment) and is secured to the rotation shaft 11 by means of the power supply rotor body C1; the main stator body 21 comprises a frame 211 in place of the plate 43, mounted on the bearing P1 and in that the power supply stator body C2 is fixed to the frame 211.

[0132] Figure 7a represents a schematic diagram according to an axial section (comprising the axis of rotation) of an electric machine according to a fifth embodiment and Figure 7b a section AA of the machine at the level of the beaks of the teeth 120 of the main rotating body 12.

[0133] This electrical machine is similar to that of the first mode except that the power stator body C2 is mounted on a bearing P1 and is tightly mounted in the opening of the main stator body 21 making them integral with each other.

[0134] Furthermore, in this example the power supply stator body C2 comprises, in addition to a part surrounding the main rotating body 12, a part mounted axially opposite the main rotating body 12.

[0135] Finally, the frame 121 of the rotor body 12 is directly mounted on the rotor shaft in this example. Such a power supply device may be brushed or inductive.

[0136] Figure 8a represents a schematic diagram according to an axial section (comprising the axis of rotation) of an electric machine according to a fifth embodiment and Figure 8b a section AA of the machine at the level of the beaks of the teeth 120 of the main rotating body 12.

[0137] This electrical machine is similar to that of the second embodiment except that the power supply device C comprises a second power supply stator body C2', the power supply rotor body C1 being located axially between the first and second power supply stator bodies C1, C1'. Each power supply stator body C1, C1' is mounted on a bearing P1, P1'. In the case of a brush power supply device C, each power supply stator body C2, C2' comprises brushes rubbing against either the same tracks of the power supply rotor body C1 or on different tracks. In the case of an inductive power supply device C, the power supply device C can be like that shown in section in Figure 12 explained below.

[0138] Furthermore, as in the previous embodiment, the rotor body 12 comprises a frame 121 secured directly to the rotor shaft (fitted for example) and the power supply stator body C2 is mounted on a bearing P1 and is mounted tightly in the opening of the main stator body 21 making them secured to each other.

[0139] The machine may include an electrical conductor in a groove or on the shaft 11 connecting the power rotor body C1 to the coil 13 to power it.

[0140] In these different embodiments described previously, the power supply device C comprises at least one part surrounded by at least one axial air gap formed between a first rotary air gap face 12a of the rotor 1 and a first stator air gap face 21a of the stator 2.

[0141] Figure 9a represents a schematic diagram according to an axial section (comprising the axis of rotation) of an electric machine according to a fifth embodiment and Figure 9b a section AA of the machine at the level of the beaks of the teeth 120 of the main rotating body 12.

[0142] This electric machine is similar to that of the third embodiment, except that the power supply stator body C2 is mounted in place of the plate of closure 43, that is to say against the external radial face 21 b of the frame 211 of the main stator body 21 and is mounted on the bearing P1.

[0143] In the various examples, the rotor shaft may comprise at one of its ends a toothed wheel or directly a rotating device such as a fan.

[0144] Figure 10 schematically represents an inductive power supply device C which may be that mounted in the second, third, fifth and eighth embodiment, and a rotation shaft 11. The power supply stator body C2 comprises an induction circuit, here in this case a ferromagnetic body C21 and an induction coil C20 mounted in this ferromagnetic body C21. The power supply rotor body C1 comprises a ferromagnetic body C11 secured to the rotation shaft 11. The power supply rotor body C1 further comprises an induced coil C10 mounted in the ferromagnetic body C11 opposite the induction circuit to transform the energy of the induction circuit when it is powered by an external source into electric current. The power supply rotor body C1 comprises a printed board C12 comprising the electronics necessary for rectifying the electric current to power the main rotary winding 13.The printed board C12 in this case covers a surface of the ferromagnetic body C11. The axial length 11 is also represented between the first end C1 a located on an external face of the printed board and the second end C1 b located in this case on one end of the ferromagnetic body C1 1 .

[0145] The axial length I2 is also represented between the first end C2a located on an external face of the ferromagnetic body C21 and the second end C2b located in this case on one end of the ferromagnetic body C21 opposite the second end C1b.

[0146] The power supply device further comprises connection terminals not shown for connecting the coil C20 to an electrical power source.

[0147] Figure 11 schematically represents an inductive power supply device C which may be an example of that mounted in the fourth embodiment and a rotation shaft 1. The power supply stator body C2 comprises an induction circuit, here in this case an induction coil C20 mounted in a ferromagnetic body C21.

[0148] According to another example, the ferromagnetic body C21 is a printed board comprising one or more traces forming the winding, the trace may be in the form of a spiral or several traces may be open concentric circles, one of the ends of which is connected to a following or preceding trace connecting them to each other in series.

[0149] The first and second power rotor bodies C1, C1' each comprise an identical ferromagnetic body C11, C11' each mounted tightly on the shaft of rotation C1, in which the induced coil C10, C10' is wound. Each power rotor body C1, C1' comprises an induced coil C10, C10' opposite the induction circuit to transform the energy of the induction circuit when it is powered by an external source, into electric current. Each power rotor body C1, C1' comprises a printed board C12, C12' comprising the electronics necessary for rectifying the electric current to power the main rotary winding 13.

[0150] In this example (as in that of Figure 10), the power supply device further comprises connection terminals not shown for connecting the coil C20 to an electrical power source.

[0151] Figure 12 schematically represents an inductive power supply device C which may be an example of that mounted in the seventh embodiment, and a rotation shaft 11. Each power supply stator body C2, C2' comprises an induction circuit, here in this case an induction coil C20, C20' mounted in a ferromagnetic body C21, C21'. The power supply rotor body C1 is integral with the rotation shaft 11. The power supply rotor body C1 comprises a first and second induced coil C10, C10' each facing the corresponding induction circuit respectively of the first and second power supply stator bodies C2, C2' to transform the energy of the induction circuit when it is powered by an external source, into electric current.The power supply rotor body C1 comprises a first and a second printed card C12, C12' comprising the electronics necessary for rectifying the electric current transformed by the first and second induced coil C10, C10' respectively to supply the main rotary winding 13.

[0152] In this example, the power rotor body C1, C1' comprises a first and a second identical ferromagnetic body C11, C11' each mounted tightly on the rotation shaft 11, in which the first and second induced coil C10, C10' are wound respectively. The first and a second printed board C12, C12' are located between the two ferromagnetic bodies C11, C11', one next to the other and could be a single printed board.

[0153] Figure 13 represents an axial flux electric machine according to a ninth embodiment, in which the stator 2 comprises a second main stator body 21' identical and integral in rotation with the first main stator body 21 and the power supply stator body C2.

[0154] The stator 2 further comprises a second main stator winding, not shown, wound in the second main stator body 21', the first and second main rotating bodies 21, 21' each comprising a plurality of teeth each forming a Tl north or south pole. The first main stator winding 13 is also not shown to simplify reading of the diagram.

[0155] The main rotating body 12 is located axially between the two main stator bodies 21, 21', also called hereinafter the central main rotating body. The central main rotating body 12 is also shown schematically in a three-dimensional view in Figure 14. In this embodiment, the frame 121 comprises a plurality of ferromagnetic sections each having a portion of the second radial face forming on each section a second air gap surface opposite the first air gap surface and in that the second air gap surface is located opposite the second main stator body 21'. In this example, the rotor comprises a plurality of magnets M1, called inter-pole magnets, mounted between each of the sections.

[0156] The rotor 1 further comprises a 121f hoop mounted around the sections of the frame 121 and a 120f hoop mounted around the tips of the teeth 120. Of course, the two hoops could be in one piece.

[0157] Furthermore, in this example, the main rotating winding comprises a coil 13a wound around a portion of a tooth 120 out of two on the side of the beak of the tooth 120 and a second coil 13b wound around another portion of a tooth 120 out of two on the side of the frame 121. Thus, each tooth 120 comprises a bare portion 120n around which none of the two coils 13a, 13b is wound (by going around). Thus, the notches 124 formed between each tooth 120 have a first axial zone filled by portions of conductors of the first coil 13a and a second axial zone filled by portions of conductors of the second coil 13b. Such a winding makes it possible to increase the copper filling rate in a notch in a simple manner. Indeed, the first coil 13a may have its last conductor turn closer to a bare part of the neighboring tooth than to the tooth around which the conductor turn is wound.

[0158] Finally, such an axial flux electric machine with these two main stator bodies 21, 21' and a central main rotary body 12 preferably comprises an inductive power supply device C according to the example of FIG. 12 by having its power supply rotor body C1 in the central main rotary body 12, in particular by making it integral with the rotation shaft 11 and the two power supply stator bodies C2, C2' are each located in the corresponding main rotary body 12, 12'.

[0159] Figure 15 represents an axial flux electric machine according to a tenth embodiment, in which the rotor 1 comprises a second main rotating body 12' integral in rotation with the rotation shaft 11, identical to that of the first main rotating body 12 and a second main rotating winding 13' wound in the second rotating body main 12'. The first and second main rotating bodies 12, 12' each comprise a plurality of teeth each forming a north or south pole.

[0160] The main stator body 21 of the stator 2 is located axially between the two main rotating bodies 12, 12' and in that each tooth 210 comprises a second air gap surface opposite the first air gap surface and in that the second air gap surface is located opposite the second main rotating body 12.

[0161] In this example, the power supply device C is inductive and is of the type shown in FIG. 11 such that the rotary power supply body C1 is connected to the first main rotary winding 13, and the second rotary power supply body C1' is connected to the second main rotary winding 13'. The power supply by the two rotary power supply bodies C1, C1 of the two main rotary windings 13, 13' is such that each tooth forming a pole of the second main rotary body 12, 12' is axially aligned with a tooth of the first rotary body having a pole of a different polarity from the first body. In particular, in this example, the main rotary windings 13, 13' have salient poles, one tooth 120 out of two.The main rotating bodies 12, 12' are offset from each other angularly so that a bare tooth 120 (i.e. the winding does not include a turn wound around the tooth) of the first main rotating body 12 is axially aligned with a tooth 120 wound by the second main winding 13', of the second main rotating body 12. Thus, in this example, the first power rotating body C1 powers the first main winding 13 in a first direction and the second power rotating body C1' powers the second main winding 13' in the other direction.

[0162] The power supply stator body C2 is integral with the main stator body 21 of the stator 2, for example by arms or by being tightly mounted. Of course, the machine could have a power supply device C comprising only one rotary power supply body C1 supplying the two main rotary windings 13, 13'. In this example, the power supply stator body C2 and the main stator body 21 could be made of resin or fiberglass, in particular formed by a printed card whose etched traces would form the power supply winding 13 and the induction coil C20.

[0163] Figure 16 schematically represents an axial section of an axial flux electric machine according to an eleventh embodiment. In this example the rotor shaft 11 comprises a pinion 110 meshed with satellites 90 of an epicyclic gear train 9. The epicyclic gear train 9 further comprises a crown 91 which can be fixed or movable as required. Of course the rotor shaft 11 can have a drive means other than the pinion 11 or the pinion 11 can be connected to another device.

[0164] In this eleventh embodiment, the electrical machine is different from the first embodiment, in that the rotor 1 is supported, on one side of the shaft 11 of the rotor 1, at the opening of the stator 2, by the stator 2 by a first track C19 and brushes of a first group of brushes C29 of the power supply device C. In particular, in this example, the only bearing between the rotor 1 and the stator 2 is formed by the brushes of the first group of brushes C29 and the track C19. The rotary power supply device C is therefore brushed, the power supply rotor body C1 comprises the first track C19 and a second track C17 electrically connected (the connection is represented by dotted lines) each to the main rotary winding 13 to electrically power it. The power supply stator body C2 further comprises, in addition to the first group of brushes C29, a second group of brushes C27 in contact with a second track C17 of the power supply rotor body C1.

[0165] The power rotor body C1 therefore comprises a first track C19 having a ring shape comprising a revolution connection surface and the power stator body C1 comprises the first group of brushes C29 and springs C28, here in this case one spring per brush, to apply a radial force on the brush of the first group of brushes C29 against the revolution connection surface of the track C19. In particular optionally, the rotor shaft 11 comprises in this example a groove in which the first track C19 is housed and here a part of each brush of the first group of brushes C29 according to its wear. The springs C28 bear against a bearing surface 218 secured to the main stator body 21. In this case, this bearing surface is surrounded by the stator winding 23. Of course, the groove of the shaft is optional, the ring can be mounted on the external cylindrical surface of the rotor shaft.

[0166] The first group of brushes C19 of the power supply stator body C2 comprises at least a first brush in contact with the revolution connection surface and a second brush aligned with the first brush radially opposite the first brush in contact with the same revolution connection surface. Preferably the first group of brushes comprises two other brushes (not shown) aligned and are angularly distributed at 90° relative to the first and second brushes of the first group of brushes. Springs exert a force on these two other brushes radially against the revolution surface of the first track C19.

[0167] The second track C17 is represented in this example as a washer-shaped track comprising a radial surface and the brushes of the second group of brushes C17 are axially supported against this radial surface by the springs C26 supported against the frame of the stator body 21.

[0168] According to another example not shown, the second track C17 is also ring-shaped and the bearing surface 218 is extended axially towards the rotating main body 11 and the springs C26 exert pressure on the brushes of the second brush group C27 radially on the second track C17 (located either in the same groove or a second groove). The brushes of the second group can be angularly offset in such a way that all of the brushes (of the first and second groups) are regularly angularly distributed around the axis of rotation. In this example preferably, the number of brushes is identical in the first and second brush groups C29, C27.

[0169] Figure 17 represents a schematic diagram according to an axial section of an electrical machine according to a twelfth embodiment. This embodiment is identical to the ninth embodiment except that the rotor 1 is supported by the stator 2 only by the power supply device C which is brushed. The stator 2 further comprises in this example a tank 28 joining the two main stator bodies. Furthermore in this example, the rotating winding 13 comprises two coils.

[0170] The power supply device C comprises a first and a second stator power supply body C2, C2'. The first stator power supply body C2 comprises a first group of brushes C29, springs C28 and a first track C19 similar to that of the eleventh embodiment except in that the spring C28 bears against a washer surrounded by the first stator winding 23.

[0171] In this example, the second stator power supply body C2' comprising the second brush group C27 and the springs C26 exerting a radial force on the second track C17 of the rotor power supply body C1, here in the form of a ring. In this case, the second stator power supply body C2' and the second track are surrounded by the frame of the second main stator body 21' of the stator 2, but could be surrounded by the second stator coil 13'.

[0172] In this example, the first and second stator power supply bodies C2, C2' each comprise only one first group of brushes C19 and each of the two tracks C19, C17' are electrically connected (represented by dotted lines) to the coils of the first and second rotor windings 13, 13' to electrically power them.

[0173] Of course, according to a variant not shown, each stator power supply body C2, C2' may comprise a second group of brushes and the rotor power supply body comprises two other tracks, and each stator power supply body C2, C2' electrically supplies a corresponding rotor coil 13, 13'. For example, the second group of brushes of the first stator power supply body C2 may comprise a second brush group as in one of the examples, shown or not shown, of the eleventh embodiment.

[0174] Figure 18 represents a schematic diagram according to an axial section of an electrical machine according to a thirteenth embodiment. This embodiment is identical to the tenth embodiment except that the rotor 1 is supported by the stator 2 only by the power supply device C which is brushed. The stator 2 further comprises in this example a static shaft 27 comprising an opening receiving the rotation shaft 11 of the rotor 1 connecting the two main rotor bodies 12, 12'. The power supply device comprises two stator power supply bodies C2, C2' and two rotor power supply bodies C1, C1'.A first pair of feed bodies includes the first stator feed body C2, with the first rotor feed body C1 feeding the first rotor winding 13 and a second pair of feed bodies includes the second stator feed body C2', with the second rotor feed body C1' feeding the second rotor winding 13'.

[0175] Each pair of power bodies is identical, the first pair C1, C2 is surrounded by the first stator winding 23 and the second pair C1', C2' is surrounded by the second stator winding 23'.

[0176] Each rotor feed body C1, C1' comprises two tracks C17', C19' (of which only those of the second rotor feed body C1' are referenced) each comprising a surface of revolution, mounted in axially aligned manner on the rotation shaft 11.

[0177] Each stator power supply body C2, C2' comprises two groups of brushes 27, 28 (of which only the groups of the first power supply body C2 are referenced) and springs 26, 28 (of which only the springs of the first power supply body C2 are referenced) each pressing radially on a brush pressing against the corresponding track.

[0178] In these embodiments in which the power supply device comprises brushes, each group of brushes is intended to receive an electrical polarity of a direct current, for example the first group of brushes a positive polarity and the second group of brushes a negative polarity.

[0179] In these embodiments in which the power supply device comprises brushes, each group may comprise more than two radially aligned brushes, for example two other radially aligned brushes. For example, the brushes are distributed regularly angularly around the X axis, i.e. at 90° for 4 brushes.

[0180] In these embodiments, the power supply device of which comprises brushes, the machine is less expensive and more axially compact. The tracks may have a U-shaped with the bottom of the U being the surface of revolution. Such a track allows the brush to be guided axially and therefore improves the support of the shaft on the rotor.

[0181] Figure 19 schematically represents an axial section of an axial flux electrical machine according to an unclaimed invention. This machine is identical to that of the thirteenth embodiment except that each pair of power supply bodies is surrounded by the ferromagnetic rotor frame 121 of the main rotor body 12, 12' of the rotor 1. Thus in this example each main rotor body 12, 12' are shown independent but can be linked for example by a device meshed with each main rotor body 12, 12' (which can comprise on either side a pinion for example).

[0182] Unless otherwise specified, the same element appearing in different figures has a single reference.

Claims

CLAIMS

1. Compact axial flux electric machine comprising: - a rotor (1) comprising: o a rotation shaft (11) with an axis of rotation (x), o a main rotating body (12) integral in rotation with the rotation shaft, made of ferromagnetic material, comprising a frame (121) and teeth (120) each extending from an internal radial face of the frame (121), the frame (121) further comprising a second external radial face (12b) opposite the first internal radial face, o a main rotating winding (13) located in the main rotating body (12), the main rotating winding (13) comprising a first rotating axial end (13a) and a second rotating axial end (13b) opposite the first axial end (13a), - a stator (2) comprising: o a main stator body (21) comprising an opening crossed by the rotation shaft (11), o a main stator winding (23) located in the main stator body (21) and secured to the latter, comprising a first axial end (23a) facing the rotary axial end (13a) of the main rotary winding (13) and a second axial end (23b) opposite the first axial end (23a) - a rotary power supply device (C) comprising: o a power supply rotor body (C1) secured to the rotation shaft (11) and electrically connected to the main rotary winding (13) to power it, o a power supply stator body (C2) rotationally secured to the main stator body (21) to transmit energy to the power supply rotor body (C1), o the power supply rotor body (C1) and the power supply stator body (C2) each comprise an axial length (11, I2) and in that at least 50% along the axial length (11, I2) of the power supply rotor body (C1) or of the power supply stator body (C2) is located axially between the external radial face (12b) of the frame (121) of the main rotating body (12) and the second axial end (23b) of the stator winding (23), characterized in that the main rotating body (12) is integral with the rotation shaft (11) via the power supply rotor body (C1).

2. Compact axial flux electric machine according to the preceding claim, wherein the feed rotor body (C1) comprises a feed rotary outer radius (r3) less than or equal to the inner radius (r1) and comprises a first and a second feed rotary axial end face (C1a, C1b) opposite each other axially, - the power stator body (C2) comprises a rotary power external radius (r4) less than or equal to the internal radius (r1) and comprises a first and a second axial power stator end face (C2a, C2b) opposite each other axially, - the first rotary power supply axial end face (C1 a) and the first stator power supply axial end face (C2a) face each other and are each located between the second axial end (13b) of the rotary winding (13) and the second axial end (23b) of the stator winding (23).

3. Compact axial flux electric machine according to one of the preceding claims, in which the rotary power supply device (C) is brushed, the power supply rotor body (C1) comprises a first track (C19) and the rotary power supply device (C) comprises a second track (C17) integral with the rotor (1), the first and second tracks (C17, C19) each being connected to the main rotary winding to electrically power it, and the power supply stator body (C2) comprising at least a first group of brushes in contact with the first track and the rotary power supply device (C) comprises a second group of brushes in contact with the second track.

4. A compact axial flux electric machine according to the preceding claim, wherein the rotor is supported by the first track and the brushes of the first brush group at least on one side of the rotor shaft.

5. Compact axial flux electric machine according to the preceding claim, in which: - the first track (C19) has a ring shape comprising a connection surface of revolution, - the first group of brushes (C29) of the power supply stator body (C2) comprises at least a first brush in contact with the revolution connection surface and a second brush aligned with the first brush radially opposite the first brush, the second brush being in contact with the same revolution connection surface, - the power supply stator body (C2) comprising at least a first and second spring (C28) each exerting a radial force on the first brush and the second brush respectively against the first track (C17), - in which the rotating support between the rotor (1) and the stator (2) in the opening is formed solely by the power supply device (C) including at least the first track (C17) in contact with the first and second brushes on the side of the first axial end and by at least two other brushes of the first or another group of the power supply device (C17, C19'), the other brushes being aligned at 90° relative to the alignment of the first and second brushes.

6. A compact axial flux electric machine according to claim 1 or 2, wherein the rotary power supply device (C) is inductive, - the power supply stator body (C2) comprising an induction circuit and - the power supply rotor body (C1) comprising: o an induced coil (C10) opposite the induction circuit to transform the energy of the induction circuit into electric current, and o electronic components to rectify the electric current transformed by the induced coil (C10), connected to the main rotary winding (13) to power it.

7. Compact axial flux electric machine according to claim 1 or 2 or 6, comprising: a second power rotor body (C1 '), a second main rotating body (12') integral with the second power rotor body (C1 ), a second main coil (13') wound in the second main rotating body (12'), a printed board comprising: o the main stator body (21), o the main stator winding (23) formed by traces etched on the printed board and o the power stator body (C2) located between the two power rotor bodies (C1, C1'), o the power stator winding formed by traces etched on the printed board. - and in which the main stator body (21) and the main stator winding are located between the two main rotating bodies (12') and the power stator body (C2) secured to the main stator body (21) is located between the two power rotor bodies (C1, C1').

8. A compact axial flux electric machine according to one of the preceding claims, wherein the power supply device (C) further comprises a second power supply rotor body (C1'), the power supply stator body (C2) being located between the first and second power supply rotor bodies (C1, C1') to power them.

9. A compact axial flux electric machine according to one of the preceding claims 1 to 8, wherein the power supply device (C) further comprises a second power supply stator body (C2'), the power supply rotor body (C1) being located between the first and second power supply stator bodies (C2, C2') to power them.

10. Compact axial flux electric machine according to one of the preceding claims, in which the main rotating body (12) has a salient pole comprising a plurality of teeth each forming a north or south pole, the main rotating winding (13) comprising a plurality of coils powered and electrically connected to the power rotor body (C1).

11. A compact axial flux electric machine according to one of claims 1 to 9, wherein the main rotating body (12) is claw-type, wherein the teeth (120) each form a north or south pole and each comprise a base each extending axially from the ferromagnetic frame (121) and a beak extending radially from the base, the teeth forming either internal claws (120i) whose base extends from an internal periphery of the frame on the side of the orifice or external claws (120e) whose base extends on the side of an external periphery of the frame opposite the orifice.

12. A compact axial flux electric machine according to the preceding claim wherein the rotor further comprises inter-tooth-base magnets between each tooth.

13. A compact axial flux electric machine according to any preceding claim, wherein the rotor further comprises inter-pole magnets between each tooth.

14. Compact axial flux electric machine according to one of the preceding claims, wherein: the rotor (1) comprises a second main rotating body (12') integral in rotation with the rotation shaft (11), identical to that of the first main rotating body (12) and a second main rotating winding (13') wound in the second main rotating body (12'), the first and second main rotating bodies (12, 12') each comprising a plurality of teeth each forming a north or south pole, - the rotary power supply body (C1) being connected to the first and second rotary windings (13, 13') such that each tooth forming a pole of the second rotary body is axially aligned with a tooth of the first rotary body having a pole of a different polarity from the first body, - the main stator body (21) being located axially between the two main rotating bodies (12, 12') and in that each tooth (210) comprises a second air gap surface opposite the first air gap surface and in that the second air gap surface is located opposite the second main rotating body (12').

15. Compact axial flux electric machine according to one of the preceding claims, in which: the stator (2) comprises a second main stator body (21 ') identical to and integral in rotation with the first main stator body (21 ) and the power stator body (C2), and a second main stator winding wound in the second main stator body (21'), the first and second main stator bodies (21, 21') each comprising a plurality of teeth each forming a north or south pole, - the main rotating body (12) being located axially between the two main stator bodies (21, 21') and in that the frame (121) comprises several angular sections and the second external radial face (12b) of the frame (121) forms on each section a second air gap surface opposite the first air gap surface and in that the second air gap surface is located opposite the second main stator body (21').

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