Rotor of electromagnetic motor having two-part magnet structure

Abstract

The invention relates to a rotor (1) of an electromagnetic motor having a body (25a, 25b) comprising a hub (2) concentric to a central axis (7). The branches (3) extend radially from the hub (2) towards a collar (8) forming the outer circumference of the rotor (1). The magnet structure (10) accommodated between two adjacent branches (3) is in the form of two sub-structures (11, 12), respectively an inner sub-structure and an outer sub-structure and extending radially between the two branches. When the rotor does not rotate, the innermost side of the inner sub-structure (11) at least partially contacts the hub (2) and its lateral face facing one of the two adjacent branches is mechanically engaged (13, 14) with the portions of the branches facing them, such that the inner sub-structure (11) is axially stopped and radially free to move relative to the rotor. The outer substructure (12) presents its outermost side with respect to the rotor to support against the collar (8).

Description

Technical Field

[0001] The invention relates to a rotor for an axial flux electromagnetic motor (electric machine) or generator, the rotor having an advantageously enlarged hub from which branches extend with a two-part magnet structure between two adjacent branches.

[0002] The invention also relates to an electromagnetic motor or generator equipped with a rotor of this type.

[0003] The invention has advantageous but non-limiting application to electromagnetic motors that deliver high power using high speed rotation of the rotor, which is achieved by the specific characteristics of the rotor according to the invention. This type of motor can be used as an electromagnetic motor in, for example, all-electric or hybrid motor vehicles.

[0004] Advantageously but not limitingly, the electromagnetic motor or generator may comprise at least one rotor framed by two stators, whereby these elements may be superimposed on one another and separated by at least one air gap on the same shaft.

[0005] In high-speed applications, it is necessary for the rotating component (ie, the rotor) to have very high mechanical strength to improve the reliability of the system.

[0006] For an axial flux electromagnetic machine, the rotor comprises a body in the form of a disc-shaped support for the magnets, having two circular faces connected by a thickness, the disc being defined between an outer rim formed by a hoop and an inner periphery defining a recess for the rotating shaft.

[0007] The magnets are each held in a disc-shaped support by a holding device, leaving spaces between the magnets.

[0008] In an axial flux motor, the peripheral (peripheral) speed of the rotor generates centrifugal forces at the level of the magnets which can become significant and limit the maximum permissible speed.

[0009] For the magnet or pole structure, a greater part of the force is absorbed by the peripheral hoop and also via the adhesive on the profile of the magnetic structure connecting it to the branch.

[0010] Axial flux motors are often used as motors with higher torque density than radial flux motors. Therefore, they can be used in low speed applications.

[0011] For high speed applications, the design of the rotor in an axial flux motor is more complex because the mechanical stresses in the rotor are very high due to the forces caused by the centrifugal effect. In addition, when the rotor components are made of conductive material, the losses from the Foucault currents dominate in the magnets as well as in the rotor components.

[0012] For rotors that must rotate at high speeds, the main disadvantage of high-speed rotating motors is the high probability of one or more magnets being separated from the rotor and at least partial breakage of the rotor. Therefore, the rotor of this type of motor must be able to withstand high-speed rotation.

[0013] Prior art teaches the skilled person to strengthen the disk-shaped support of one or more magnets to resist centrifugal forces. This requires specific materials for the disk-shaped support and increasing its size by making it thicker to make the disk-shaped support more rigid.

[0014] This solution is not yet completely satisfactory, since the motor or generator thus equipped with the disc-shaped support is heavier and more expensive to manufacture.

[0015] One solution could be to construct a web of elongated monolithic (monolithic) magnets in a fiber and resin structure to reduce Foucault currents, and use a non-conductive composite material for the rotor, ideally a fiberglass rotor, with hoops placed on the periphery of the rotor to receive the forces due to the centrifugal effect.

[0016] However, for applications where speeds become very high, mechanical stresses become such that it is necessary to reduce the weight of the magnets to achieve these rotational speeds. However, the torque that the motor must deliver is proportional to the surface area of ​​the magnets interacting with the magnetic field generated by the stator. Therefore, a reduction in the surface area of ​​the magnets results in a reduction in torque and, therefore, a reduction in motor power. Background Art

[0017] EP-A-0353042, representing the most recent prior art, describes a rotor for an electromagnetic motor or generator having a body comprising an inner hub concentric with the central axis of rotation of the rotor, branches extending radially from the inner hub with respect to the central axis of rotation towards a hoop forming a circular outer periphery of the rotor, at least one magnet housed in each space defined between two adjacent branches, the width of each branch decreasing with distance from the inner hub, terminating in a conical point abutting against the hoop, the width of each magnet increasing with distance from the inner hub, terminating in a hoop surrounding the rotor.

[0018] This prior art document does not allow for a support for a plurality of permanent magnets which, on the one hand, can effectively hold the permanent magnets supported by the rotor by preventing the magnets from detaching from the rotor while effectively compensating for centrifugal forces, and on the other hand, whose mechanical strength allows the rotor to rotate at very high speeds.

[0019] FR-A-1475501 does not describe a rotor, but only describes a magnet structure comprising a plurality of single magnets without specifying the application of the magnet structure, and does not indicate that the disadvantages of the above two prior art documents can be overcome by using this type of magnet structure having a plurality of single magnets, because there is no mention of using this type of magnet structure for a rotor in this document. Summary of the invention

[0020] The problem solved by the present invention is the design of a rotor for supporting a plurality of permanent magnets, the rotor being equipped with a hoop for an electromagnetic axial flux motor, which on the one hand allows to effectively retain the permanent magnets supported by the rotor by preventing the magnets from detaching from the rotor while effectively compensating for centrifugal forces, and on the other hand its mechanical strength allows the rotor to rotate at very high speeds.

[0021] To this end, the invention relates to a rotor of an electromagnetic motor (electric machine) or generator, the rotor having a body and a magnet structure, the body comprising an inner hub concentric with the central rotation axis of the rotor and branches extending radially from the inner hub relative to the central rotation axis to a hoop forming the circular outer periphery of the rotor, the magnet structure forming a magnetic pole housed in each space defined between two adjacent branches associated with the magnet structure, characterized in that each magnet structure is in the form of two different substructures, the two different substructures being, according to their position in the rotor, an inner substructure and an outer substructure extending radially between the two associated adjacent branches, the innermost side of the inner substructure on the rotor at least partially contacting the inner hub when the rotor is not rotating, and the lateral (transverse) faces thereof are each facing one of the two associated adjacent branches by mechanical engagement with the facing parts of the associated adjacent branches and are abutted in the axial direction of the rotor but free to move in the radial direction of the rotor, and the outer substructure is in contact with the hoop relative to the outermost side of the rotor.

[0022] The mechanical joint according to the invention makes it possible to hold the inner substructure in the axial direction relative to the rotor while allowing slight radial displacements thereof, which is not possible with lateral adhesive connections of the one-piece magnet structure against the branches.

[0023] The inventive step of the invention is to modify the shape of each magnet structure housed between two adjacent branches by creating two different parts or substructures. The forces exerted on the outer substructure are absorbed by the hoop and the forces exerted on the inner substructure are absorbed by the part of the branch adjacent to the rotor hub through mechanical absorption.

[0024] The invention thus makes it possible to absorb centrifugal forces which are particularly adapted to the position of the substructure in the rotor and which are different for the inner substructure than for the outer substructure.

[0025] For a rotor diameter of approximately 300 mm, this allows the rotor to reach rotational speeds of greater than 15,000 rpm.

[0026] As mentioned above, for the rotor of an axial flux machine, the magnets are adhesively connected to the branches, which makes it possible to transmit a portion of the centrifugal force in the branches that varies according to the modulus of the adhesive and therefore its temperature.

[0027] In the case of the invention, adhesive becomes unnecessary primarily for the inner substructure in order to distribute the load on the branches, and the portion of the force transmitted into the branches is no longer a function of the temperature, but only of the mass distribution of the two substructures of the magnet structure.

[0028] In addition to the ability to increase the rotational speed of the rotor, an additional advantage is that more magnet mass can be placed on the outer radius of the rotor. Given the same magnet mass, this improves torque production at the same speed relative to the rotor of an axial flux machine with a magnet structure in a single-piece magnet block.

[0029] Advantageously, the mechanical engagement of each lateral face of the internal substructure of each magnet structure against the facing parts of the associated adjacent branches can be achieved by means of a convex part carried laterally by each internal substructure engaging in a concave part carried by a part of the facing branches of the internal substructure, or by the positioning of the convex and concave parts being reversed.

[0030] These optional measures make it possible to ensure that the centrifugal forces exerted on the inner substructure are transmitted into the branches while at the same time ensuring the axial retention of the inner substructure in the rotor.

[0031] Each internal substructure is advantageously embedded in a first composite material layer completely enveloping said internal substructure, said first composite material layer being configured to form said convex portions, each convex portion being carried on a lateral side by each internal substructure.

[0032] The two inner substructures and the outer substructure of each magnet structure between two adjacent branches are embedded in a second composite material layer completely enclosing the magnet structure, the rotor also being enclosed in a third composite material layer.

[0033] Thus, there can be a triple coating in the rotor, whereby the composition (ingredients) of the coatings can be different, depending on their role. The first coating relates to the coating of the substructure. This coating can be more flexible to allow deformation of the substructure. The second coating is the coating of the magnet structure or poles and can contain more fibers to make it more rigid. Finally, the third coating relates to the rotor itself and is also advantageously reinforced.

[0034] Providing three coatings that complement each other ensures that the desired high mechanical strength of the rotor rotating at high speeds is achieved, particularly since the composition of each coating is specifically selected depending on the positioning of the coating in the rotor and the elements that the coating surrounds.

[0035] Advantageously, the legs are rhombus-shaped in cross-section and are connected to the inner hub by a foot which widens as it approaches the hub, the two innermost sides of the rhombus of two associated adjacent legs on the rotor framing the inner substructure of each magnet structure, and the two outermost sides of the rhombus of two associated adjacent legs on the rotor framing the outer substructure of each magnet structure, the inner substructure of each magnet structure completely filling a first shell defined between the two innermost sides of the rhombus of two associated branches in the space between two associated adjacent branches, and the outer substructure of each magnet structure completely filling a second shell defined between the two outermost sides of the rhombus of two associated branches in the space between two associated adjacent branches.

[0036] This type of configuration of the diamond shape makes it possible to limit the radial displacement of the inner substructure, while a more massive magnet can be placed towards the outside of the rotor close to the hoop to act as an outer substructure.

[0037] Advantageously, the bases of two associated adjacent branches in contact with the inner hub are separated by a middle portion of the inner hub which is at least partially in contact with the innermost side of the inner substructure on the rotor.

[0038] Advantageously, the inner substructure and the outer substructure of each magnet structure are separated by a gap.

[0039] An operating gap is desirable to prevent the inner substructures from contacting the associated outer substructure. Thus, each inner substructure is not in contact with the walls of the facing branches and therefore all centrifugal forces are absorbed by the hoops rather than by the facing parts of the branches of the rotor body.

[0040] The operating gap may be filled with a flexible resin or adhesive that is more flexible than the branches of the body so as not to transmit the centrifugal loads of each internal substructure to the hoop.

[0041] Advantageously, at least one substructure of each magnet structure is constructed from a plurality of monolithic (integral) magnets held together by fibre-reinforced insulating material.

[0042] An additional synergy achieved by the present invention is that the rotor can have individual magnets grouped into inner or outer substructures between each branch.

[0043] This makes it possible to have a substructure with multiple individual magnets. It has been determined that the substructure with multiple individual magnets is highly insensitive to space harmonics or currents generated by the stator windings. Therefore, the losses generated in the substructure are very low and the output (especially at high speeds) is very high.

[0044] One of the optional measures of the invention is to decompose the inner or outer substructure, which may be a whole magnet or a magnetic pole, into a plurality of small magnets or micromagnets according to the prior art.

[0045] Large magnets experience greater losses from Foucault currents than their equivalents consisting of small or micro magnets. The use of small or micro magnets makes it possible to reduce these losses, which are detrimental to the operation of the electromagnetic actuator.

[0046] Applicants have discovered that multiple individual magnets in a magnet structure result in a magnet structure with much higher mechanical strength while maintaining almost similar magnetic properties to a single magnet, with a surface area equal to n times the basic surface area of ​​n individual magnets when there are n individual magnets.

[0047] Advantageously, each single magnet has an elongated shape extending in the axial direction of the rotor, each single magnet has a polygonal shape, or each single magnet has an at least partially oval outline, which shape or oval outline includes a first portion forming the body of the single magnet, which first portion has a larger cross-section and extends over a greater length of the single magnet than at least a second longitudinal end portion pointing to the associated longitudinal end of the single magnet, the cross-section of the second longitudinal end portion decreasing as it approaches the longitudinal end.

[0048] It is known that in order to obtain a magnetic field of optimum strength, the ideal volume of the magnet must be close to a cube or cylinder with a length equal to the diameter. It is also known that increasing the length of the magnet beyond the diameter will not achieve any increase in the magnetic field.

[0049] However, in an alternative embodiment, the present invention overcomes this bias towards using elongated monolithic magnets.

[0050] The length of the individual magnets is significantly greater than the diameter or diagonal of their planar longitudinal surfaces, contrary to widespread practice.

[0051] The ovoid magnets may be faceted. This creates individual magnets in the form of "crystals" associated with each other, which do not meet over the entire surface of the facets or longitudinal faces, although the layers of resin and glue form a mesh network at the ends of the faceted blocks with limited contact areas between the magnets.

[0052] Alternatively, for a single magnet with a perfect oval shape having a rounded first portion, the contact between two adjacent single magnets is smaller and may be only a point contact, and substantially corresponds to a small arc between the two single magnets.

[0053] The grooves may be cut to the size of the contact arc between two adjacent individual magnets to receive glue, preferably in the form of resin.

[0054] Advantageously, each individual magnet is in the form of a slice having a thickness at least less than one tenth of its length, the slices forming individual magnets divided into at least one of the substructures of each magnet structure described above by cuts in radially orthogonal planes in the rotor.

[0055] Advantageously, at least one of the substructures of each magnet structure composed of a plurality of single magnets comprises at least one grid structure having cells (single chambers), each cell defining a shell for a corresponding single magnet, the internal dimensions of each shell making it possible to introduce a single magnet into the interior thereof while leaving a space between the shell and the single magnet filled with fiber-reinforced insulating material, the grid structure being made of fiber-reinforced insulating material.

[0056] The lattice structure remains in place as it can be applied in layers of composite material. This type of lattice structure makes it possible to hold the individual magnets during the manufacture of the substructure and has the advantage of representing an additional solidifying element of the substructure, whereby the lattice structure can also contain reinforcing fibers.

[0057] For example, it is known that honeycomb grid structures can enhance the strength of an element (in this case a substructure). Inserting individual magnets into hexagonal shells can ensure that they are held in place. The walls of the shells act as electrical insulators, and the density of the shells in the substructure can be significantly increased. The honeycomb structure can be made of fiber-reinforced insulating composite materials.

[0058] Advantageously, the hub and branches may be made of fiberglass cast in resin.

[0059] These glass or reinforcement fibers help increase the strength of the rotor, particularly bending strength and resistance to buckling.

[0060] Advantageously, the rotor has circular surfaces which delimit it axially, wherein the cover disk is located on at least one of the circular surfaces of the rotor.

[0061] This is mainly, but not exclusively, applicable to the substructure of the magnet structure comprising a plurality of unit magnets. The large magnets used in the prior art for the rotor dissipate a large amount of heat. This dissipation prevents the use of axial retaining means in the form of composite cover discs, and the heat dissipation may affect the properties of the coating, while accelerating the aging of the coating and the magnets.

[0062] Therefore, composite cover plates are not often used in the prior art because they cannot withstand the dissipation of heat generated by the magnets.

[0063] Because the present invention preferably uses multiple single magnets instead of the compact magnets of the prior art, heat dissipation is reduced and the composite cover disks can be used as axial retaining means, these disks advantageously replace the axial retaining means between the magnets and the rotor body, if necessary, it is necessary to modify the magnets or their coatings to provide additional attachment means to the rotor-borne attachment means.

[0064] Advantageously, the distal end of each branch is supported against a hoop and the rotor body is formed from two equivalent body parts axially aligned in the rotor.

[0065] This makes it possible to achieve part of the mechanical engagement between the associated branch and the internal substructure by forming a concave portion, for example in the form of a groove, between the two body portions, which concave portion receives a convex portion carried by each internal substructure.

[0066] The invention also relates to a method for producing a rotor of this type, the method comprising the following steps:

[0067] introducing an internal substructure between each pair of two associated adjacent branches of one of the two main parts,

[0068] Combine the two main parts.

[0069] An external substructure is introduced between each pair of two associated adjacent branches of the body, each external substructure being in the radial extension direction of the internal substructure,

[0070] A hoop is positioned against the distal end of each branch and the outer substructure is adhesively attached against the hoop.

[0071] Thus, easy manufacturing can be achieved by using a rotor in the form of two parts bonded to each other, leaving a gap between them, and a part of the mechanical engagement between each internal substructure and its associated branch in the form of a concave portion that can accommodate one or more convex portions of each internal substructure. When the magnet structure is coated as a whole, the method can be modified by replacing the first step with the introduction of the magnet structure and its internal and external substructures between each pair of two associated adjacent branches of one of the two body parts and by eliminating the third stage.

[0072] The present invention relates to an axial flux electromagnetic motor or generator, characterized in that it comprises at least one rotor as described above, said electromagnetic motor or generator comprising at least one stator carrying at least one winding, said electromagnetic motor or generator comprising one or more air gaps between said at least one rotor and said at least one stator.

[0073] Advantageously, the electromagnetic motor or generator comprises at least one rotor associated with two stators. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The invention is illustrated in the accompanying drawings, in which:

[0075] Figure 1 shows an exploded view of an embodiment of a rotor according to the present invention,

[0076] Figure 2 A highly schematic axial cross-sectional view of an embodiment of a magnet structure forming part of a rotor according to the invention is shown, wherein the elements are shown separated from one another for greater visibility,

[0077] Figure 3 showing a perspective front view of an embodiment of an inner substructure of a magnet structure forming part of a rotor according to the invention,

[0078] Figure 4 shows a radial cross-sectional view of an embodiment of a magnet structure forming part of a rotor according to the invention,

[0079] Figure 5 shows a perspective view of an embodiment of a body consisting of a hub and branches forming part of a rotor according to the invention,

[0080] Figure 6 Shows Figure 5 An enlarged perspective view of a branch of the main body shown,

[0081] Figure 7 shows a first alternative embodiment of a single magnet comprised in a substructure of a magnet structure forming part of a rotor according to the invention,

[0082] Figure 8 shows a second alternative embodiment of a single magnet comprised in a substructure of a magnet structure forming part of a rotor according to the invention,

[0083] Fig. 9 A third alternative embodiment of a single magnet included in a substructure of a magnet structure forming part of a rotor according to the invention is shown,

[0084] Fig.10A fourth alternative embodiment of a single magnet shown alone and included in a substructure of a magnet structure forming part of a rotor according to the invention is shown.

[0085] The embodiments shown in the accompanying drawings are shown by way of example and do not limit the present invention in any way. They are schematic diagrams intended to facilitate understanding of the present invention and are not necessarily drawn to scale for practical applications. In particular, the dimensions of the various parts do not represent reality. DETAILED DESCRIPTION

[0086] For the sake of brevity, the term "magnet" is not repeated after the word "substructure", assuming that the structure containing two substructures is a magnet structure, and this is the case for all inner and outer substructures.

[0087] In the following, only one adjacent branch 3, one single magnet structure 10, one single inner substructure 11 and one single outer substructure 12 are referenced, where applicable. The same applies to Figure 2 and Figures 7 to 10 A single individual magnet in the, and a single layer of adhesive between the individual magnets, and a single mesh where applicable.

[0088] However, everything stated for one of these labeled elements applies to all similar unlabeled elements.

[0089] Reference is made to all of the accompanying drawings and more particularly to Figures 1 to 6 And specifically refer to Figure 1 , Figure 2 and Figure 5 , these figures show a rotor 1 with two branches 3 , wherein a magnet structure is located between the two branches 3 , which magnet structure is shown separated and consists of an inner substructure 11 and an outer substructure 12 .

[0090] This type of rotor 1 is used for an electromagnetic motor (electric machine) or generator, advantageously an axial flux motor or generator. The rotor 1, advantageously substantially circular, has a body 25a, 25b comprising an inner hub 2 concentric with the central rotation axis 7 of the rotor 1 or the longitudinal median axis of the rotor 1.

[0091] The branches 3 extend radially in the rotor 1 , relative to the central axis of rotation 7 , starting from the inner hub 2 towards a hoop 8 which forms the circular outer periphery of the rotor 1 .

[0092] exist Fig.10 An inner substructure 11 and an outer substructure 12 of at least one magnet structure marked in FIG. 1 are housed in each space defined between two adjacent branches 3 .

[0093] Thus, according to the invention, each magnet structure 10 is in the form of two distinct substructures 11, 12, respectively an inner substructure and an outer substructure, according to their position in the rotor 1. Each pair of two distinct substructures 11, 12 (inner substructure and outer substructure, respectively) has its outer substructure 12 extending radially its inner substructure 11 between two associated adjacent branches 3.

[0094] Each internal substructure 11 on the rotor 1 is characterized by its innermost side being opposite to the inner hub 2 without being connected to the inner hub 2 and being in at least partial contact with the inner hub 2 at least when the rotor 1 is not rotating and the centrifugal force does not push each internal substructure 11 toward the periphery of the rotor 1 .

[0095] The lateral (transverse) faces of each internal substructure 11 on the rotor 1 are each opposite one of the two associated adjacent branches 3 and are in mechanical engagement 13, 14 against facing portions on the associated adjacent branch.

[0096] This mechanical engagement 13 , 14 ensures a stop in the axial direction of the rotor 1 and a limited free movement in the radial direction of the rotor 1 away from the inner hub 2 towards the hoop 8 .

[0097] In order to avoid undesired radial movements (e.g. vibrations) during rotation of the rotor 1, it is advantageous to provide limited friction in the mechanical joints 13, 14 in the radial direction between the branches 3 associated with each inner substructure 11. The friction coefficient may be selected taking into account the expected rotational speed of the rotor 1 and the magnitude of the centrifugal forces acting on the inner substructure 11 as a result.

[0098] Each outer substructure 12 on the rotor 1 contacts the hoop 8 with its outermost side relative to the rotor 1 .

[0099] If especially in Figure 3 , Figure 5 and Figure 6 As can be seen in the figure, the mechanical connection 13, 14 of each lateral face of the internal substructure 11 of each magnet structure against the facing parts of the associated adjacent branches can be achieved by a convex part 13 accommodated in a concave part 14, which is supported by a part of the branch 3 facing the internal substructure 11, and the convex part 13 is supported laterally by each internal substructure 11.

[0100] The above configuration can be reversed by providing the inner substructure 11 with a concave portion and the branches with a convex portion.

[0101] For example, a guide rail as a male part 13 carried laterally by each internal substructure 11 can be inserted into a groove as a female part 14 carried by a portion of the branch 3 opposite the internal substructure 11. It is also possible to use a tenon as a male part 13 fitting into a mortise or recess carried by the branch 3. The reverse is also possible.

[0102] It is also possible to use any mechanical connection as long as the connection used ensures axial immobilization of the rotor 1 and limited free movement of the rotor 1 in radial direction.

[0103] Special References Figure 2 and Figure 3 Each inner substructure 11 or outer substructure 12 may be embedded in a first composite material layer 15 that completely surrounds the inner substructure 11 or outer substructure 12 .

[0104] In the case of an internal substructure 11 , the first composite material layer 15 may be configured to form convex portions 13 , each convex portion 13 being carried on one side in a lateral direction by each internal substructure 11 .

[0105] Special References Figure 2 , the two substructures (inner substructure 11 and outer substructure 12 ) of each magnet structure 10 between two adjacent branches 3 may be embedded in a second composite material layer 16 that completely surrounds the magnet structure 10 .

[0106] In this case, the second composite material layer 16 (when present) may be shaped to carry a convex portion 14 on each of its lateral sides.

[0107] Furthermore, the rotor 1 can also be embedded in the third composite material layer 17 , whereby this third layer 17 can also cover the at least one cover disk 27 .

[0108] In this Figure 2 A portion of the third layer 17 is shown in FIG. 1 , separated from the second layer 16 and the cover disk 27 so that it is visible in the illustration, whereas in reality the third layer is adjacent to the second layer, with or without the cover disk 27 in between.

[0109] The composite material layers may contain reinforcing fibers. The fiber content may vary from one layer to another. Thus, without limitation, the first layer 15 of the inner substructure 11 may have a lower fiber content and be slightly more deformable than the second layer 16 or the third layer 17 so that when the rotor rotates, the inner substructure 11 may move slightly closer to the outer substructure 12.

[0110] The magnet volume of each outer substructure 12 may be greater than the magnet volume of each inner substructure 11. Figure 4 , where the outer substructure may be in the shape of a frustum of a cone open towards the hoop 8 .

[0111] Each outer magnet substructure 12 is placed with its largest opening facing the outer periphery of the rotor 1 (ie, hoop 8) so that the number of magnet components placed on the periphery of the rotor 1 can be increased, thereby increasing the total magnetic surface area.

[0112] As in Figure 5 As can be best seen for a single branch, the bases of two adjacent branches 3 may be separated by a middle portion 9 of the inner hub 2 .

[0113] The hub 2 and the branches 3 may be made of glass fibres cast in resin. Strong plastic fibres may also be used to increase the strength of the rotor 1, in particular its bending strength and resistance to buckling.

[0114] In order to strengthen the rotor 1, the body of the rotor 25a, 25b and the branches 3 may be integral. The branches 3 may or may not be attached to the hoop 8 by their tapered ends 3b.

[0115] As especially considered in the combination Figure 1 , Figure 2 , Figure 5 and Figure 6 As can be seen in Figure 6 yes Figure 5 , which is an enlarged view of a portion of the branch surrounded and marked A, the branch 3 may have in cross section a diamond shape 19 connected to the inner hub 2 by legs 18 that widen towards the outside of the diamond 19 closer to the hub 2 .

[0116] The diamond shape 19 of two associated adjacent branches 3 in the cross section can frame the inner substructure 11 of each magnet structure 10 relative to the two innermost faces of the rotor 1. The diamond shape 19 of two associated adjacent branches 3 in the cross section can frame the outer substructure 12 of each magnet structure 10 relative to the two outermost faces of the rotor 1.

[0117] The internal substructure 11 of each magnet structure 10 may completely fill the first housing 20 defined between the two innermost cross sections 19 of the rhombus of the two associated branches 3 , in the space between the two associated adjacent branches 3 .

[0118] The inner substructure 11 of each magnet structure 10 may leave a lateral cavity opposite the legs 18. This lateral cavity may be less than five percent of the surface area filled by the inner substructure 11.

[0119] The outer substructure 12 of each magnet structure 10 may completely fill the second housing 21 defined between the two outermost cross sections of the rhombus 19 of the two associated branches 3 in the space between the two associated adjacent branches 3 .

[0120] The bases of two adjacent associated branches 3 in contact with the inner hub 2 may be separated by a middle portion 9 of the inner hub 2. The middle portion 9 of the inner hub 2 may be in contact at least partially with the innermost side of the rotor 1 of the inner substructure 11.

[0121] The inner substructure 11 and the outer substructure 12 of each magnet structure 10 may be separated by a gap 22 .

[0122] The gaps 22 may be circular, and a series of gaps 22 in the magnet structure of the rotor 1 may form a circle centered at the center of the rotor 1 , through which the central rotation axis 7 passes.

[0123] The operating gap 22 may be filled with a flexible resin or adhesive that is more flexible than the branches 3 of the rotor 1 , so as not to transmit the centrifugal loads of the internal substructure 11 to the hoop 8 .

[0124] Alternatively, the gap 22 can also remain empty.

[0125] Although at least one of the inner substructure 11 or the outer substructure 12 may contain only one magnet, reference Figures 7 to 10 Referring to other drawings without reference numerals, at least one of the substructures 11 , 12 of each magnet structure 10 may also be composed of a plurality of single magnets 4 , 4 c , 4 d bonded together by a fiber-reinforced insulating material 23 .

[0126] like Figure 7 As shown, each single magnet 4, 4c, 4d may be elongated and extend in the axial direction of the rotor 1. Figure 7 Only one of them is marked in the figure) and should not be confused with the magnet structure 10 or the large magnet not shown in the figure.

[0127] Therefore, each magnet structure 10 may be three-dimensional and may be composed of a plurality of individual magnets 4, 4c, 4d.

[0128] exist Figure 7 In the embodiment, each single magnet 4 of the plurality of single magnets is therefore in the shape of a polygon, preferably a parallelepiped.

[0129] exist Fig. 9 There are four parallelepipedal monomer magnets 4, which are larger than Figure 7 The single magnet 4 in the Fig. 9 There are four in particular.

[0130] exist Fig.10 In the embodiment, each individual magnet 4c may have an at least partially oval profile.

[0131] The oval single magnet 4c may include a first portion 4a forming the body of the single magnet 4c, the first portion 4a having a larger cross-section and extending over a greater length of the single magnet 4c than at least a second longitudinal end portion 4b pointing toward the associated longitudinal end of the single magnet 4c, the cross-section of the second longitudinal end portion 4b decreasing as it approaches the longitudinal end.

[0132] For any type of single magnet, the single magnets can be directly adjacent to each other and partially contact each other. The individual magnets 4 can be connected together with an adhesive. A plurality of single magnets 4, 4c, 4d form a magnet grid, and there is no holding element between them except for the adhesive, and each magnet 4, 4c, 4d is in direct contact with the adjacent magnets.

[0133] It is possible to have a magnet structure 10 with an inner substructure 11 and an outer substructure 12 each comprising different individual magnets.

[0134] exist Figure 2 In the embodiment, in the substructure 11 of the magnet structure 10 , the individual magnets 4 are adhesively connected together without a grid between them, while in the other substructure 12 , the individual magnets are adhesively connected together and inserted into the grid structure 24 .

[0135] Thus, at least one of the substructures 11 , 12 of each magnet structure 10 consisting of a plurality of individual magnets may comprise at least one grid 24 having cells (cells), each cell defining a housing for a respective individual magnet 4 .

[0136] The internal dimensions of each housing may be just sufficient to allow the introduction of the individual magnets 4 therein, while leaving a space between the housing and the individual magnets 4 that is filled with the fiber-reinforced insulating material of which the grid structure is made.

[0137] exist Figure 2 , reference numeral 23 indicates an insulating material filling a space between two single magnets 4 .

[0138] It is also possible to design a magnet structure 10 without a grid in its inner substructure 11 and outer substructure 12 .

[0139] Thus, the individual magnets may be square, rectangular or any other shaped pixelated magnets.A resin or adhesive 23 may be injected between the magnets to form a rough blank of both the inner and outer substructures.

[0140] The pixels may be implemented in an orientation tilted at any angle relative to the axis of symmetry of the inner substructure 11 or the outer substructure 12 comprising them.

[0141] Different individual magnets may be provided in the same magnet structure 10 from one substructure 11 or 12 to the associated substructure 12 or 11 .

[0142] In another embodiment, Figure 8 As shown, each single magnet may be in the form of a slice 4d, the thickness of which is at least less than one tenth of its length. Figure 8 Six individual magnets 4d are shown, each of which is in the form of a slice.

[0143] The slices 4d forming the single magnet may be separated in the at least one of the substructures 11, 12 of each magnet structure 10 by cuts in a radially orthogonal plane relative to the rotor 1. The empty space between two slices 4d may be filled with a resin or adhesive as the insulating material 23.

[0144] The hub 2 and the branches 3 may be made of fiberglass cast in resin and may be in one piece or in multiple pieces.

[0145] The hoop 8 of the rotor 1 may be made of glass fiber or carbon fiber. The hoop 8 may circumferentially surround the magnet structure 10 on the outer periphery of the rotor 1 .

[0146] If necessary, the hoop 8 helps to radially retain the magnet structure 10 and mechanically engage the inner substructure 11 with the branch 3. The distal end of the branch 3 can be attached to the hoop 8 or not attached to the hoop 8 but in contact with the hoop 8. The hoop 8 is particularly Figure 1 and Figure 4 Visible in.

[0147] The rotor 1 may have a circular surface axially delimiting it, Figure 2 The cover disk 27 visible in FIG. 2 is located on at least one circular face of the rotor 1 . Advantageously, each circular face of the rotor 1 has a cover disk 27 .

[0148] This prevents the magnet structure 10 from axially moving between the two branches 3. The cover disk 27 is Figure 2 1 and 2. It is shown in a highly schematic manner in FIG. 1, separated from the magnet structure 10, in order to make it more clearly visible.

[0149] If especially in Figure 1 As can be seen in FIG. 2 , the body of the rotor 1 may be in the form of two equivalent body parts 25a, 25b (preferably two concentric disks adhesively connected to each other) aligned axially with respect to the rotor 1 .

[0150] The spacing left between the two disks makes it possible to locally realize in the branch 3 a concave portion 14 for the facing parts of the internal substructure 11, 12, which concave portion 14 is particularly Figure 5 and Figure 6and is necessary for the mechanical engagement 13 , 14 of each lateral face of the internal substructure 11 of each magnet 10 with the facing portion of the associated adjacent branch, by cooperating with corresponding convex portions 13 laterally carried on both sides of each internal substructure 11 .

[0151] If especially in Figure 5 and Figure 6 As can be seen in the figure, for the single main body portion 25a shown, although this also applies to the other portion 25b, in a preferred embodiment, each main body portion 25a, 25b includes an internal contour 26a which is smaller in size and has a diamond shape similar to the external contour of each main body portion 25a.

[0152] Reference combination considered Figure 1 , Figure 5 and Figure 6 When the two body parts 25a, 25b are pressed against each other and their inner profiles 26a face each other, a groove 13 is formed, which forms a concave portion defined inside the two body parts 25a, 25b pressed against each other.

[0153] As an alternative to a two-part body, it is also possible to imagine a one-piece body having a recess on the lateral side of the branch as a concave portion.

[0154] The invention also relates to a method for manufacturing a rotor 1 in two parts as described above. The first step of the method is to introduce previously shaped internal substructures 11, each forming a closed solid, each internal substructure 11 housed between a pair of two adjacent associated branches 3 of one of the two main parts 25a, 25b of the rotor 1.

[0155] The second step consists in bonding the two body parts 25a, 25b together, for example by means of an adhesive.

[0156] The third step is to introduce an external substructure 12 between each pair of two associated adjacent branches 3 of the body 25a, 25b.

[0157] Each outer substructure 12 is located in the radial extension direction of the inner substructure 11 .

[0158] The fourth step consists in positioning the hoop 8 against the distal end of each branch and subsequently in engaging the external substructure 12 against the hoop 8 .

[0159] It should be noted that the internal substructure 11 is not adhesively connected to the branches 3 or the hub 2 .

[0160] Alternatively, complete magnet structures can be manufactured, each magnet structure being formed as a whole individually, each magnet structure comprising an inner substructure 11 and an outer substructure 12 joined together, the first step of the alternative method being to introduce a previously formed magnet structure 10 between each pair of two adjacent branches 3 associated with one of the two main parts 25a, 25b of the rotor 1, each magnet structure 10 forming a closed entity.

[0161] In this alternative variant, the third step of the above-described process is then omitted.

[0162] Finally, the invention relates to an axial flux electromagnetic motor or generator comprising at least one such rotor 1, comprising at least one stator carrying at least one winding, comprising one or more air gaps between at least one rotor 1 and at least one stator.

[0163] The electromagnetic motor or generator may preferably comprise at least one rotor 1 associated with two stators.

Claims

1. A rotor (1) of an electromagnetic motor or generator, the rotor (1) comprising: a body (25a, 25b) comprising an inner hub (2) concentric with a central axis of rotation (7) of the rotor (1) and branches (3) extending radially from the inner hub (2) towards a hoop (8) relative to the central axis of rotation (7), the hoop (8) forming a circular outer periphery of the rotor (1); a magnet structure (10) forming a magnetic pole housed in each space defined between two adjacent branches (3) associated with the magnet structure (10), It is characterized in that Each magnet structure (10) is in the form of two separate substructures (11, 12), which, according to their position in the rotor (1), are respectively an inner substructure and an outer substructure extending radially between two associated adjacent branches (3), and when the rotor (1) is not rotating, the innermost side of the inner substructure (11) of the rotor (1) at least partially contacts the inner hub (2) and its lateral faces, each facing one of the two associated adjacent branches (3), are mechanically engaged (13, 14) with the facing parts of the associated adjacent branches, so that the inner substructure (11) is axially stopped in the direction of the rotor (1) and is free to move in the radial direction of the rotor (1), and relative to the outer substructure (12) of the rotor (1) presents its outermost side relative to the rotor (1) against the hoop (8).

2. The rotor (1) according to claim 1, in, The mechanical engagement (13, 14) of each lateral face of the internal substructure (11) of each magnet structure (10) with the facing parts of the associated adjacent branches is achieved by a convex part (13) laterally supported on both sides of each internal substructure (11) being accommodated in a concave part (14) supported by the part of the branch (3) facing the internal substructure (11), or the positioning of the convex part (13) and the concave part (14) is reversed.

3. A rotor (1) according to the preceding claim, in, Each internal substructure (11) is embedded in a first composite material layer (15) that completely covers the internal substructure (11), and the first composite material layer (15) is configured to form the convex parts (13), and each convex part (13) is laterally supported on one side by each internal substructure (11).

4. Rotor (1) according to the preceding claim, in, The two inner and outer substructures (11, 12) of each magnet structure (10) between two adjacent branches (3) are embedded in a second composite material layer (16) completely surrounding the magnet structure (10), and the rotor (1) is also surrounded by a third composite material layer (17).

5. A rotor (1) according to any one of the three preceding claims, in, The branches (3) have a cross section in the shape of a rhombus (19), the rhombus (19) being connected to the inner hub (2) by means of legs (18), the legs (18) becoming wider as they approach the hub (2), the two faces of the rhombus (19) of two associated adjacent branches (3) in the cross section closest to the rotor (1) framing the inner substructure (11) of each magnet structure (10), and the two faces of the rhombus (19) of two associated adjacent branches (3) in the cross section farthest from the rotor (1) framing each magnet structure (10) ), the internal substructure (11) of each magnet structure (10) completely fills the first shell (20) defined between the two innermost cross-sectional diamond faces (19) of the two associated branches (3) in the space between the two associated adjacent branches (3), and the external substructure (12) of each magnet (10) completely fills the second shell (21) defined between the two outermost diamond cross-sections (19) of the two associated branches (3) in the space between the two associated adjacent branches (3).

6. A rotor (1) according to any one of the preceding claims, in, The inner and outer substructures (11, 12) of each magnet structure (10) are separated by a gap (22).

7. A rotor (1) according to any one of the preceding claims, in, At least one of the substructures (11, 12) of each magnet structure (10) is composed of a plurality of individual magnets (4, 4c, 4d) bonded together by fiber-reinforced insulating material (23).

8. The rotor (1) according to claim 7, in, Each single magnet (4, 4c) is elongated and extends in the axial direction of the rotor (1), each single magnet (4) is polygonal in shape or each single magnet (4c) has an at least partially oval outline, the oval shape or outline includes a first portion (4a), the first portion (4a) forms the main body of the single magnet (4c), the first portion (4a) has a larger cross-section and extends over a greater length of the single magnet (4c) than at least a second longitudinal end portion (4b), the second longitudinal end portion (4b) points to the associated longitudinal end of the single magnet (4c) and its cross-section decreases as it approaches the longitudinal end.

9. The rotor (1) according to claim 7, in, Each single magnet (4, 4c, 4d) is in the form of a slice (4d), the thickness of the slice (4d) being at least less than one tenth of its length, and the slice (4d) forming the single magnet is separated in at least one of the substructures (11, 12) of each magnet structure (10) by a cut in a radially orthogonal plane in the rotor (1).

10. A rotor (1) according to any one of the three preceding claims, in, At least one of the substructures (11, 12) of each magnet structure (10) composed of a plurality of single magnets (4, 4c, 4d) is combined with at least one grid structure (24) having cells, each cell defining a shell for a corresponding single magnet (4, 4c, 4d), the internal dimensions of each shell enabling the introduction of a single magnet (4, 4c, 4d) therein while leaving a space filled with fiber-reinforced insulating material (23) between the shell and the single magnet (4, 4c, 4d), the grid being made of fiber-reinforced insulating material.

11. A rotor (1) according to any one of the preceding claims, in, The inner hub (2) and the branches (3) are made of glass fibre cast in resin.

12. A rotor (1) according to any one of the preceding claims, in, The rotor (1) has a circular surface which delimits it axially, and the cover disk (27) is arranged on at least one circular surface of the rotor (1).

13. A rotor (1) according to any one of the preceding claims, in, The distal end of each branch (3) contacts the hoop (8), and the body (25a, 25b) of the rotor (1) is formed by two equivalent body parts (25a, 25b) axially aligned in the rotor (1).

14. A method for producing a rotor (1) according to the preceding claim, said method The following steps are involved: introducing an internal substructure (11) between each pair of two associated adjacent branches (3) of one of the two body parts (25a, 25b), The two main parts (25a, 25b) are combined, An external substructure (12) is introduced between each pair of two associated adjacent branches (3) of the body (25a, 25b), each external substructure (12) extending radially of the internal substructure (11), A hoop (8) is positioned against the distal end of each arm (3) and the outer substructure (12) is adhesively connected against the hoop (8).

15. An axial flux electromagnetic motor or generator, It is characterized in that It comprises at least one rotor (1) according to any one of claims 1-13, the electromagnetic motor or generator comprising at least one stator carrying at least one winding, the electromagnetic motor or generator comprising one or more air gaps between the at least one rotor (1) and the at least one stator.

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