Magnet structure with unit magnets having a rhombic cross section

Abstract

The present invention relates to a unit magnet (4) in the form of an elongated polyhedral block having magnetization lines extending along its length, wherein the elongated block forming each unit magnet (4) has a rhomboid cross-section without right angles at the vertices, wherein the cross-section of each unit magnet (4) is less than 25 mm. 2 Furthermore, the ratio of the longest diagonal of the rhomboid cross-section of each unit magnet (4) to the length of the unit magnet (4) is less than 0.5. The present invention also relates to a magnet structure (10) comprising a plurality of such unit magnets (4).

Description

Technical Field

[0001] The present invention relates to a unit magnet in the form of an elongated pin having a polyhedral shape and a non-square rhomboid cross section, and also to a magnet structure including such a unit magnet, and a rotor for an axial flux electromagnetic motor or generator including at least one such magnet structure. Background Technology

[0002] This invention has advantageous, but not limiting, applications in electromagnetic actuators that utilize the high rotational speed of a rotor to transmit high power, achieved by using one or more magnet structures according to the invention. Such electromagnetic actuators can be used, for example, in all-electric or hybrid motor vehicles.

[0003] The closest prior art, in particular the prior art described in WO 2019 / 243996 A1, has proposed breaking down a magnet structure (which may be a complete magnet or magnetic pole according to the prior art) into multiple small magnets or micro magnets.

[0004] Therefore, document WO 2019 / 243996 A1 discloses a three-dimensional magnet structure consisting of multiple unit magnets in the form of elongated pins. The magnet structure has a thick, flat or rounded leading and trailing edges joined by lateral surfaces, and the unit magnets are arranged such that they have a first longitudinal end adjacent to the leading edge of the magnet structure and a second longitudinal end adjacent to the trailing edge of the magnet structure.

[0005] Unit magnets are grouped together against each other in the magnet structure to form a bundle, while each unit magnet is individually encapsulated in a non-conductive resin layer.

[0006] In fact, large magnets suffer greater eddy current losses than their equivalents composed of small or micro magnets (as proposed in WO 2019 / 243996 A1). Therefore, using small or micro magnets as unit magnets can reduce magnetic losses that are detrimental to the operation of electromagnetic actuators.

[0007] Document EP 0 353 042 A1 describes a rotor for an electromagnetic motor or generator having a body including an inner hub coaxial with a central axis of rotation of the rotor; branches extending radially from the inner hub toward a ring forming an outer circular periphery of the rotor relative to the central axis of rotation; and at least one magnet housed in a space defined between two adjacent branches, each magnet having a width that increases with distance from the inner hub to abut against the ring surrounding the rotor.

[0008] This document does not allow for the provision of a support for multiple permanent magnets that can, on the one hand, effectively hold the permanent magnets carried by the rotor, prevent the magnets from detaching from the rotor, and simultaneously effectively compensate for centrifugal force, while on the other hand, exhibit mechanical strength that allows the rotor to rotate at very high speeds.

[0009] Reference FR 1 475 501 A1 does not describe a rotor, but only a magnet structure comprising several unit magnets. It does not specify the application of this magnet structure, nor does it imply that using such a magnet structure with several unit magnets can overcome the shortcomings of the last cited reference. In fact, this reference does not mention using such a magnet structure with several unit magnets for a rotor. Summary of the Invention

[0010] The first problem solved by the present invention is to further reduce magnetic loss in a magnet structure having multiple unit magnets bundled together and individually coated with resin by adopting a specific geometry that is as advantageous as possible for each unit magnet.

[0011] This is particularly important because in high-speed rotating rotor applications, losses need to be reduced to achieve optimal efficiency. Furthermore, miniaturization is increasingly sought after, especially in motor vehicle applications.

[0012] Therefore, it is important to have a compact system, which is achieved by reducing the mass and space occupied by the actuator, while also having very good mechanical behavior of the moving parts to improve the reliability of the system.

[0013] In particular, in the construction of a magnet structure having multiple unit magnets that are electrically insulated from each other by being individually wrapped in a resin layer that fills the grooves between the unit magnets, stress concentrations in the resin layer located in the grooves between the unit magnets should be reduced. These concentrations are caused by centrifugal forces generated during the rotation of a rotor comprising one or more magnet structures at high speeds, approximately equal to or greater than 10,000 rpm.

[0014] The second problem addressed by the present invention is to reduce the stress borne by a magnetic structure comprising multiple unit magnets bundled together and individually coated with resin under centrifugal stress conditions (e.g., when an assembly carrying one or more magnetic structures, such as a rotor, is set to rotate).

[0015] Therefore, the present invention relates to a unit magnet, which is in the form of an elongated pin with a polyhedral shape and magnetization lines extending along its length, characterized in that the elongated pin forming each unit magnet has a rhomboid cross-section without right angles at the apex, and the cross-section of each unit magnet is less than 25 mm. 2 Furthermore, the ratio of the longest diagonal of the rhomboid cross-section of each unit magnet to the length of that unit magnet is less than 0.5.

[0016] In the case of a rhomboid cross-section, the two diagonals connect opposite vertices of the cross-section, with one diagonal being larger than the other. A ratio less than 0.5 corresponds to the maximum length of the longest diagonal of 5mm for a minimum unit magnet length of 10mm.

[0017] The non-square rhomboid cross-section of each unit magnet reduces the passage of eddy currents within it, making the passage more restricted than that provided by unit magnets with rectangular or square cross-sections.

[0018] Furthermore, the non-square rhomboid cross-section of each unit magnet enables the provision of unit magnets that, when inserted into a magnet structure and individually coated with resin in a specific orientation of the face of the structure susceptible to centrifugal force during rotation of the magnet structure along the axis of symmetry, reduce stress concentrations on the magnet structure caused by centrifugal forces applied to the magnet structure.

[0019] The cross-section of each unit magnet is less than 25 mm. 2 Each unit magnet is specified to be in the form of a slender pin or dowel with a small cross-section, rather than a rod or rod-shaped element. The ratio of the longest diagonal of the rhomboid cross-section of each unit magnet to the length of that unit magnet is also less than 0.5. These values ​​have proven to be optimal for designing unit magnets that reduce eddy currents.

[0020] The present invention also relates to a three-dimensional magnet structure comprising a plurality of unit magnets, each unit magnet as described above, wherein the magnet structure has a thick, flat or rounded leading and trailing edges joined by lateral surfaces, the unit magnets being arranged to have a first longitudinal end adjacent to the leading edge of the magnet structure and a second longitudinal end adjacent to the trailing edge of the magnet structure, the unit magnets being grouped together abutting against each other in the magnet structure to form a bundle, and being individually encapsulated in a non-conductive resin layer, characterized in that the unit magnets are arranged in the magnet structure such that their sides form an angle of less than 90 degrees relative to a tangential force extending parallel to the tangent of the leading edge, the tangential force being applied to the magnet structure during rotational movement.

[0021] The distinguishing feature of the magnet structure described in this invention is the non-square rhomboid geometry of the cross-section of each unit magnet constituting the magnet structure.

[0022] In contrast to conventional magnet structures that typically have multiple unit magnets in the form of pins with rectangular, square, or even circular cross-sections, the magnet structure with multiple unit magnets according to the present invention is designed to reduce the mechanical stress it experiences when subjected to centrifugal force.

[0023] The benefits of reducing eddy currents associated with unit magnets with non-square rhomboid cross sections mentioned above can also be applied to magnet structures that contain such unit magnets.

[0024] Furthermore, structures with such multiple unit magnets have been found to possess a strong ability to be insensitive to space harmonics or currents generated by the stator windings. Therefore, the losses generated in the magnet structure are very low, and the efficiency is particularly high at high speeds. This magnet structure can form magnetic poles or complete magnets.

[0025] Advantageously, the rhomboid cross-section is constant along the entire length of each unit magnet forming the pin. "Pin" should be understood in a broad sense as a slender body rather than specifically as a conical shape.

[0026] Advantageously, the angle between the two opposite vertices of the rhomboid cross section is between 100 degrees and 200 degrees between the two sides on which the tangential force is applied.

[0027] Advantageously, the non-conductive resin layer is reinforced with fibers.

[0028] Advantageously, the non-conductive resin layer includes reinforcing fibers, such as glass fibers or plastic material fibers.

[0029] Advantageously, the resin of the non-conductive layer is selected to have a higher stress strength under compressive stress than under tensile stress. The compressive strength can, for example, be twice the tensile strength, and this difference between compression and tension varies depending on the speed, temperature, and desired performance.

[0030] The present invention also relates to a rotor that rotates about its center, characterized in that it comprises a single magnet structure or a plurality of magnet structures as described above, the one or more magnet structures being concentrically arranged at the center of the rotor.

[0031] For high-power motors, the rotor rotates at high speeds. A major drawback of high-speed motors is the high likelihood of the pin-shaped unit magnet detaching from the magnet structure, leading to a risk of structural and rotor damage. This can be avoided by using pin-shaped unit magnets with a non-square rhomboid cross-section to reduce the stress on the magnet structure under centrifugal stress.

[0032] Advantageously, when there is a single magnet, the magnet structure forms a single magnet extending around the center of the rotor; or when there are multiple magnets, the magnet structure is a continuous paving that forms continuous magnetic poles.

[0033] Advantageously, the rotor has a body comprising an inner hub concentric with the central axis of rotation of the rotor; branches extending radially from the inner hub toward a ring (ring) forming the outer circular periphery of the rotor relative to the central axis of rotation; and a magnetic structure forming magnetic poles, which are accommodated in each space defined between two adjacent branches associated with the magnetic structure.

[0034] Advantageously, the rotor has a circular surface that defines it in the axial direction, and a cover disk is disposed on at least one circular surface of the rotor.

[0035] Finally, the present invention relates to an axial flux electromagnetic motor or generator, characterized in that it comprises at least one rotor as described above.

[0036] The present invention also relates to a method for manufacturing such a magnet structure, characterized by comprising the following steps: - Multiple unit magnets are cut from a magnetized sheet having length, width, and thickness in three dimensions that form the sheet, according to the three dimensions of the magnetized sheet, wherein at least two types of cuts have non-right-angle angles between them. - Position and maintain the unit magnets at a certain distance from each other. - A resin layer is injected around the unit magnet to encapsulate it.

[0037] By cutting in three dimensions, particularly along the width and length of the sheet, it has been found that the unit magnet has improved magnetic properties compared to a considerable portion of the magnetized sheet.

[0038] The positioning of a unit magnet can be achieved by receiving the magnet in a grid, in which case the grid becomes part of the magnet structure when it is encapsulated in a resin layer.

[0039] Alternatively, positioning can be done outside or inside the blank of the magnet structure, for example by connecting all the unit magnets of the same magnet structure together at the base, which may or may not belong to the final encapsulated magnet structure. Attached Figure Description

[0040] Other features, objects, and advantages of the invention will become apparent from the following detailed description and with reference to the accompanying drawings, which are given by way of non-limiting example, in which: [ Figure 1 [This is an enlarged schematic diagram of a lateral cross-section of a unit magnet in the form of an elongated pin with a square cross-section, according to the prior art. During the rotation of a rotor including the magnet structure, a tangential force is applied perpendicularly to the longitudinal side of each unit magnet forming part of the magnet structure.] [ Figure 2[Image 1] is an enlarged schematic diagram of the lateral cross-section of a unit magnet in the form of an elongated pin according to an embodiment of the present invention. The cross-section of the unit magnet is in the form of a non-square rhombus. The tangential force is applied during the rotation of the rotor including the magnet structure to form a non-right angle with the longitudinal side of each unit magnet forming part of the magnet structure. [ Figure 3 [This is a schematic front perspective view of a magnet structure based on the prior art, showing a single magnet in the form of an elongated pin with a square cross-section.] [ Figure 4 [This is a schematic front view of a magnet structure having a unit magnet in the form of an elongated pin with a non-square rhomboid cross-section, according to a first embodiment of the present invention.] [ Figure 5 [This is a schematic front view of a magnet structure according to a second embodiment of the present invention, having a unit magnet in the form of an elongated pin with a non-square rhomboid cross-section, the vertex angle of which differs from that of the first embodiment.] [ Figure 6 [Illustrated front view of a rotor according to an embodiment of the present invention, comprising a unit magnet having an elongated pin-shaped magnet having a non-square rhomboid cross-section, the rotor including branches that separate the magnet structure.] Detailed Implementation

[0041] The accompanying drawings are given by way of example and do not limit the invention. They constitute schematic diagrams intended to facilitate understanding of the principles of the invention and are not necessarily drawn to scale for actual application. In particular, the dimensions of different parts do not represent actual conditions.

[0042] In the following text, Figure 6 All branches are labeled as a single branch 3. The same applies to the single magnet structure labeled 10 in the attached figure.

[0043] exist Figures 4 to 6 In the diagram, all unit magnets are identified as single pin-shaped unit magnets 4, as shown in... Figure 4 and Figure 5 The single resin layer 23 located between the unit magnets 4 is as indicated in the diagram.

[0044] Everything described with respect to one of these identified elements applies to all similar unidentified elements.

[0045] Figure 2 and Figures 4 to 6 Embodiments of the unit magnet 4, magnet structure 10, or rotor 1 having magnet structure 10 according to the present invention are shown respectively.

[0046] Figure 1 and Figure 3A unit magnet 4' with a square cross-section according to the prior art and a magnet structure 10' including this type of unit magnet are shown respectively. The reference numerals for common elements in all these figures are kept the same, except that the unit magnet with a square cross-section in the prior art is 4' instead of 4, and the magnet structure with a unit magnet having a square cross-section is 10' instead of 10.

[0047] For more specific reference Figure 1 and Figure 2 These figures show cross-sections of unit magnets 4', 4 in the form of elongated bodies, such as pins or dowels, intended to be housed within magnet structures 10', 10, which... Figure 1 and Figure 2 Not shown in the patent application, but in the present patent application Figures 3 to 6 As shown in the image.

[0048] exist Figure 1 In the present invention, the unit magnet 4' is in the form of a slender pin, which is advantageously a parallelepiped, and the cross section is square.

[0049] exist Figure 2 In the present invention, the cross section of unit magnet 4 is a non-square rhomboid cross section SL. The square cross section is a special form of the rhomboid cross section SL, which is not within the scope of the present invention.

[0050] Related to the first problem at the foundation of this invention, Figure 1 and Figure 2 The arrows inside the cross section SL symbolically represent the paths P' and P' of the eddy currents through the pin-shaped unit magnets 4' and 4', which appear when the unit magnets 4' and 4' are subjected to a changing magnetic field.

[0051] exist Figure 1 As shown by the arrows in the cross-section of unit magnet 4', these currents tend to flow along path P' until they reach the boundary formed by the sides of the parallelepiped created by unit magnet 4'.

[0052] exist Figure 2 As shown by the arrow in the non-square rhomboid section SL of unit magnet 4, although this section SL occupies the area of... Figure 1 The cross-section SL has the same area as a square cross-section, but it is flatter along the first axis and more elongated along another axis perpendicular to the first axis. This causes the vortex (whose path P is symbolized by the arrow inside the cross-section SL) to flow over a smaller area.

[0053] Given that resistance is inversely proportional to flow area, the eddy currents are smaller in the case of unit magnet 4 with a non-square rhomboid cross section SL, resulting in reduced losses.

[0054] Also of interest is that the non-square rhomboid shape is closer to the shape of the sheets used in magnetic circuits, which is optimal for minimizing eddy current losses.

[0055] Related to the second problem at the foundation of the invention, arrow Ft indicates that when the magnet structure including the pin-shaped unit magnets 4', 4 is set to rotate (e.g., forming as...), Figure 6 The tangential force applied to each pin-shaped unit magnet 4', 4 (part of the rotor 1 of the electric motor shown) is a component of the motor.

[0056] and Figure 1 Relatedly, the tensile stress in the resin covering the unit magnet 4', which is in the form of a square cross-section pin, is characterized by the parameter σ' and can be expressed by the following equation: dividing the tangential force Ft by the transverse area S' of the unit magnet 4' facing the tangential force Ft: σ' = Ft / S' and Figure 2 Relatedly, the tensile stress in the resin of the unit magnet 4, which is in the form of a pin with a non-square rhomboid cross section SL, is characterized by the parameter σ, and the angle α is the inclination angle of the lateral area S of the side on which the tangential force Ft is applied in the non-square rhomboid relative to the tangential force Ft.

[0057] Tensile stress can be expressed by the following equation: dividing the tangential force Ft by the transverse area S of the unit magnet 4 with a non-square rhomboid cross section SL: σ = Ft·cosα / S The area S of the lateral side of a rhombus is related to the area S' of the lateral side of a square by the following equation: S = S' / cosα σ = Ft·cos 2 α / S' Main Reference Figure 2 The present invention relates to a unit magnet 4, which is in the form of an elongated pin with a polyhedral shape and magnetization lines extending along its length.

[0058] The slender pins forming each unit magnet 4 have a rhomboid cross-section SL without right angles at the apex, and are therefore non-square. The rhomboid cross-section SL of each unit magnet 4 is less than 25 mm. 2 Furthermore, the ratio of the longest diagonal of the rhomboid cross section SL of each unit magnet 4 to the length of that unit magnet is less than 0.5.

[0059] These size characteristics allow the unit magnet 4 to be classified as a micromagnet and clearly distinguished from magnets in the form of rods or rod-shaped elements. Furthermore, these characteristics enable a significant reduction in eddy currents flowing within each unit magnet 4.

[0060] Main Reference Figure 2 and Figures 4 to 6 The present invention relates to a three-dimensional magnet structure 10, which is composed of a plurality of unit magnets 4, each of which is described above.

[0061] The magnet structure 10 has a thick, flat or rounded leading edge 5 and a trailing edge 6 joined by lateral surfaces 9. The unit magnet 4 is configured to have a first longitudinal end adjacent to the leading edge 5 of the magnet structure 10 and a second longitudinal end adjacent to the trailing edge 6 of the magnet structure 10. Therefore, the unit magnet 4 extends in the thickness direction of the magnet structure rather than extending tangentially to the leading edge 5 or trailing edge 6 as a rod of a magnet.

[0062] exist Figures 3 to 5 In the middle, magnet structures 10' and 10 include those for insertion Figure 6 Lateral lug 11 in the rotor shown.

[0063] exist Figure 6 Therefore, it can be observed that the pin-shaped unit magnet 4 according to the invention extends in the thickness direction of the magnet structure 10, and thus also extends in the thickness direction of the rotor 1, rather than extending on the circumference of the rotor 1.

[0064] The unit magnets 4 are grouped together against each other in the magnet structure 10 to form a bundle, and are individually encapsulated in the non-conductive resin layer 23.

[0065] "Bundle", "bundle" or "cluster" refers to the unit magnets 4 being grouped together, roughly parallel to each other, and separated only by grooves of just the required size for receiving the non-conductive resin layer 23 covering them.

[0066] This grouped magnet cannot be compared to a bar, which is a set of bar-shaped elements that are spaced apart from each other and, where applicable, each does not extend along the thickness of rotor 1, as shown in document FR 3 014 255 A1.

[0067] refer to Figure 2 and Figures 4 to 6 In one or each magnet structure 10, the unit magnet 4 is configured such that its side forms an angle of less than 90 degrees with respect to a tangential force Ft parallel to the tangent of the leading edge 5, which is applied to the magnet structure 10 as a centrifugal force during the rotational motion of the magnet structure 10.

[0068] The magnet structure 10 described in this invention consists of unit magnets 4 in the form of basic pins with a non-square rhomboid cross section SL.

[0069] The unit magnets 4 in the blank of the magnet structure 10 can be held together in advance by a heel portion present on the rear of the magnet structure 10, which is not shown in the figures.

[0070] The blank of the magnet structure 10 is then covered with a thermosetting resin layer 23, except for the front, which is trimmed to expose the unit magnet 4.

[0071] Therefore, the resin permeates into the grooves provided between each pin-shaped unit magnet 4. This arrangement allows the hollow spaces between the unit magnets 4 to be filled, while simultaneously enhancing the mechanical strength of the magnet structure 10.

[0072] The resin used is specially selected based on its mechanical strength properties under tension and compression to prevent damage that may occur under the operating conditions of the magnet structure 10, especially when it rotates at high speeds, such as greater than 10,000 rpm and thus is subjected to significant centrifugal forces.

[0073] For more specific reference Figure 6 This magnet structure 10 is intended to be integrated into the rotor 1. The rotor 1 can be the rotor of an electromagnetic motor or a generator.

[0074] This is not a limitation; such rotor 1 may have a body including an inner hub 2 concentric with the central axis of rotation 7 of rotor 1.

[0075] Branch 3 can extend radially from the inner hub 2 toward the ring (ring) 8 forming the outer circular periphery of the rotor 1 relative to the central axis of rotation 7. Figure 6 In the diagram, branch 3 is shown as a polygonal shape with a basic rectangle, but branch 3 can also be conical with a tip pointing toward ring 8.

[0076] At least one magnet structure 10 is housed in each space defined between two adjacent branches 3, the magnet structure 10 comprising a pin-shaped unit magnet 4 with a non-square rhomboid cross section SL.

[0077] The magnet structure 10 having multiple unit magnets 4 can be bonded to the inner hub 2 by an adhesive present on the contact surface between the magnet structure 10 and the inner hub 2 of the rotor 1.

[0078] When this rotor 1 is subjected to significant rotational speeds, each gridded magnet structure 10 generates a centrifugal force perpendicular to the longitudinal edge of the structure 10, i.e., a centrifugal force in the radial direction. The adhesive and the ring 8 of the rotor 1 bear a portion of these forces; however, due to the greater rigidity of the ring 8 relative to the adhesive, a significant percentage of the force is transmitted to the ring.

[0079] The sliding between each magnet structure 10 and the ring 8 (which are not directly bonded to each other) is caused by centrifugal force and also produces a tangential component parallel to the longitudinal edge of the magnet structure 10. This component then stretches the grooves between the unit magnets 4 housed in the magnet structure 10 in this region, and these grooves are filled with resin layer 23.

[0080] The tangential component is particularly significant at the outer radius of the magnet structure 10. On the other hand, due to the bonding between the magnet structure 10 and the adhesive, the tangential component does not exert a large effect at the inner radius of the magnet structure 10. Therefore, this region at the outer radius of the magnet structure 10 mainly bears the tensile force caused by centrifugal force in the radial direction.

[0081] Therefore, the more significant the centrifugal force, the more significant the tensile force in the groove between the unit magnets 4.

[0082] In the case of the magnet structure 10 with a unit magnet 4 having a square or rectangular shape as suggested by the prior art, the resin layer 23 located in the groove is completely stretched.

[0083] In the case of the magnet structure 10 according to the present invention, the component of stress in the direction of the groove is multiplied by a factor k = cos 2 α, where α represents the tilt angle of the groove relative to the axis of symmetry of the unit magnet.

[0084] Therefore, the inclination angle of the groove affects the influence of the tangential component of the centrifugal force at the outer radius and the influence of the centrifugal force at the inner radius. This inclination angle is advantageously the angle between the tensile stress and the tangential force. The larger the inclination angle of the groove, the greater the reduction in the tensile stress component, because it will be multiplied by cos..., which is always less than 1. 2 α.

[0085] Furthermore, by favoring the compressive stress of the resin and reducing the tensile stress, the average fracture limit of the resin under compression is four times greater than that under tension.

[0086] In summary, based on existing technology and such Figure 3 In the magnet structure 10' shown, the tensile stress in the resin in the groove between the unit magnets 4' of the magnet structure 10' is high when subjected to centrifugal force. However, the magnet structure 10 according to the present invention is designed to facilitate the compressive stress of the resin 23, and thus reduces the tensile stress in the groove between the unit magnets 4 when subjected to centrifugal force.

[0087] This method is feasible because the grooves are non-parallel and non-perpendicular to the longitudinal edges of the magnet structure 10 with multiple unit magnets 4, and because the resin has an average compressive strength that is four times its tensile strength. The absence of right angles between the two consecutive sides of the basic pin forming the unit magnet 4 also avoids stress concentration localized at such angles in the resin.

[0088] Therefore, the present invention provides an innovative means to reduce the stress borne by a magnet structure 10 having multiple unit magnets 4 under centrifugal stress, thereby improving its durability and performance.

[0089] The performance contribution is particularly evident at the upper and lower ends (i.e., at the outer and inner radii of the magnet structure 10), where, in the case of the magnet structure 10 according to the prior art, the resin layer 23 is stretched, particularly in the radial and orthogonal radial directions.

[0090] Advantageously, but not limitingly, the resin layer may be a thermosetting epoxy resin.

[0091] The rhomboid cross section SL of each unit magnet 4 can be constant over the entire length of each unit magnet 4 forming a pin.

[0092] like Figure 4 and Figure 5 As shown, the angle between the two opposite vertices of the rhomboid section SL between the two sides on which the tangential force is applied can be between 100 degrees and 200 degrees.

[0093] The non-conductive resin layer 23 of the pin-shaped unit magnet 4, which is individually covered with a non-square rhomboid cross section SL, can be reinforced with fibers, such as reinforcing fibers, like glass fibers or plastic material fibers.

[0094] A resin with a non-conductive layer can be selected so that its stress strength under compression is higher than its stress strength under tension.

[0095] The rotor 1, which rotates about its center according to the present invention, may include a single magnet structure 10 or multiple magnet structures 10 as described above. One or more magnet structures 10 are concentrically arranged at the center of the rotor 1.

[0096] When there is only one magnet, the magnet structure 10 forms a single magnet extending around the center of the rotor 1. When there are multiple magnets, the magnet structure 10 is a continuous paving that forms continuous magnetic poles.

[0097] Simulations show that 17,500 rpm is the limiting speed for a parallelepiped pin with a rectangular cross-section (i.e., oriented at 0° and 45° relative to the axis of symmetry of the unit magnet), which is attributed to the strength of the resin (approximately 107 MPa).

[0098] On the other hand, non-square rhomboid magnets exhibit better performance and can rotate at speeds greater than 17,500 rpm, with a stress of 14 MPa at the outer radius of the resin and approximately 20 MPa at the inner radius.

Claims

1. A unit magnet (4), which is in the form of an elongated pin with a polyhedral shape and has magnetization lines extending along its length, characterized in that, The slender pins forming each unit magnet (4) have a rhomboid cross-section (SL) without right angles at the apex, and the cross-section of each unit magnet (4) is less than 25 mm. 2 Furthermore, the ratio of the longest diagonal of the rhomboid section (SL) of each unit magnet (4) to the length of the unit magnet (4) is less than 0.

5.

2. A three-dimensional magnet structure (10) comprising a plurality of unit magnets (4), each unit magnet (4) being a unit magnet according to claim 1, the magnet structure (10) having a thick, flat or rounded leading edge (5) and trailing edge (6) joined by lateral surfaces (9), the unit magnets (4) being configured to have a first longitudinal end adjacent to the leading edge (5) of the magnet structure (10), and a second longitudinal end adjacent to the trailing edge (6) of the magnet structure (10), the unit magnets (4) being grouped together abutting each other in the magnet structure (10) to form a bundle, and individually encapsulated in a non-conductive resin layer (23), characterized in that, The unit magnet (4) is configured in the magnet structure (10) such that its side forms an angle of less than 90 degrees with respect to a tangential force (Ft) extending parallel to the tangent of the leading edge (5), the tangential force (Ft) being applied to the magnet structure (10) during rotational motion.

3. The magnet structure (10) according to the preceding claim, wherein, The rhomboid cross section (SL) is constant over the entire length of each unit magnet (4) forming the pin.

4. The magnet structure (10) according to any one of the preceding two claims, wherein, Between the two sides on which the tangential force (Ft) is applied, the angles of the two opposite vertices of the rhomboid section (SL) are between 100 degrees and 200 degrees.

5. The magnet structure (10) according to any one of the preceding three claims, wherein, The resin (23) of the non-conductive layer is selected to have a higher stress resistance under compression than under tension.

6. A rotor (1) that rotates about its center, characterized in that, It includes one or more magnet structures (10) according to any one of claims 2 to 5, wherein the one or more magnet structures (10) are concentrically arranged at the center of the rotor (1).

7. The rotor (1) according to the preceding claim, wherein, When it is a single magnet, the magnet structure (10) forms a single magnet extending around the center of the rotor (1); or when it is a plurality of magnets, the magnet structure (10) is a continuous paving forming continuous magnetic poles.

8. The rotor (1) according to any one of the preceding two claims, having a body comprising an inner hub (2) concentric with a central axis of rotation (7) of the rotor (1); branches (3) extending radially from the inner hub (2) relative to the central axis of rotation (7) toward a ring (ring) (8) forming an outer circular periphery of the rotor (1); and a magnet structure (10) forming magnetic poles, the magnet structure being accommodated in each space defined between two adjacent branches (3) associated with the magnet structure (10).

9. The rotor (1) according to any one of the preceding three claims, wherein, The rotor (1) has a circular surface that defines it in the axial direction, and a cover disk is disposed on at least one circular surface of the rotor (1).

10. An axial flux electromagnetic motor or generator, characterized in that, It includes at least one rotor (1) according to any one of the preceding four claims.

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