Unitary magnet having an ovoid configuration, and magnet structure comprising multiple unitary magnets

Abstract

The invention relates to a unitary magnet (1) that has an elongate shape and an at least partially ovoid contour as the unitary magnet (1) comprises a first portion (1a) forming a body of the unitary magnet (1) that has a larger cross-section and extends over a greater portion of the length of the unitary magnet (1) than at least one second longitudinal end portion (1b) that points towards an associated longitudinal end of the magnet and has a decreasing cross-section towards the longitudinal end.

Claims

1. Magnet structure (2) in three dimensions comprising: a plurality of unitary magnets (1), characterized in that the unitary magnets (1) have an elongated shape in the form of an ellipsoid of revolution or polygon, each unitary magnet (1) comprising a first portion (1a) forming the body of the unitary magnet (1) having a larger cross-section and extending over a greater length of the unitary magnet (1) than at least one second longitudinal end portion (1b) pointing toward an associated longitudinal extremity of the magnets (1), with a decreasing cross-section approaching the longitudinal extremity, the unitary magnets (1) being directly adjacent to one another and being partly in contact, the magnets (1) being adhesively connected by the deposition of adhesive on the areas of unitary magnets (1) in contact, the plurality of unitary magnets (1) creating a mesh structure of magnets without the interposition of retention elements other than the adhesive between them.

2. The magnet structure (2) according to claim 1, in which the at least one second longitudinal extremity portion (1b) is rounded, having a convex shape, a crown of the convex shape forming the associated longitudinal extremity.

3. The magnet structure (2) according to claim 1, in which the at least one second longitudinal end portion (1b) has on its crown a median facet (5) forming the longitudinal extremity.

4. The magnet structure (2) according to claim 1, in which the at least one second longitudinal end portion (1b) comprises lateral facets (4) inclined toward a longitudinal axis of the magnet (1) approaching the associated longitudinal extremity of the magnet, the inclined lateral facets (4) extending between a large base (4a) connected to the first portion (1a) forming the body of the magnet and a small base forming a longitudinal extremity of the magnet.

5. The magnet structure (2) according to claim 1, in which the inclined lateral facets (4) are rounded to be convex.

6. The magnet structure (2) according to claim 1, in which each longitudinal end portion of the magnet comprises a second longitudinal end portion (1b).

7. The magnet structure (2) according to claim 1, in which the first portion (1a) forming the body of the unitary magnet (1) having a larger cross-section and extending over a greater length of the unitary magnet (1) is rounded, having its largest cross-section toward a longitudinal median portion of the magnet (1) and decreasing in cross-section toward the longitudinal extremities of the magnet (1).

8. The magnet structure (2) according to claim 1, in which the first portion (1a) forming the body of the unitary magnet (1) is in the shape of a polygon with longitudinal facets (3).

9. The magnet structure (2) according to claim 8 in which the first portion (1a) having the longitudinal facets (3), each of the inclined lateral facets (4) of the at least one second portion (1b) are longitudinally extended on the unitary magnet (1) by a longitudinal facet (3) of the first portion (1a).

10. The magnet structure (2) according to claim 1 in which the areas of the unitary magnets (1) in contact have beveled edges (6, 6a) rounded into an exterior contour of each unitary magnet (1) in contact with another unitary magnet (1), adhesive being deposited exclusively on the beveled edges (6, 6a) of the unitary magnets (1).

11. A linear or rotary electromagnetic actuator, characterized in that it comprises a magnet structure (2) or a plurality of magnet structures (2) according to claim 1, the magnet structure or structures (2) being part of a rotor (7) that rotates around its center, the magnet structure or structures (2) being arranged concentrically around the center of the rotor (7).

12. An electromagnetic actuator according to claim 11, in which, when unitary, the magnet structure (2) forms a single magnet extending over the actuator or, when multiple, the magnet structures (2) are successive blocks forming successive alternating magnetic poles.

13. A method for the fabrication of a magnet structure (2) according to claim 1, characterized in that it comprises the following steps: cutting out from a magnetized tile having a length, a width and a thickness forming three dimensions of the tile a plurality of unitary magnets (1) according to the three dimensions of the magnetized tile, the unitary magnets having at least partly an ovoid shape, determination of partial contact areas on each unitary magnet (1) with each magnet that is adjacent to it when the magnets are adjacent to one another, adhesive connection of each unitary magnet (1) by deposition of a resin for each unitary magnet (1) only in determined partial contact areas, and positioning of the unitary magnets (1) thus adhesively connected adjacent to one another, a partial contact between two adjacent unitary magnets (1) being established in the contact areas.

14. The method according to claim 13, in which a layer of composite is injected around the unitary magnets (1) thus placed in contact and adhesively connected for their coating.

15. The magnet structure (2) according to claim 1, in which the first portion (1a) forming the body of the unitary magnet (1) in the shape of a cylinder with a circular or ovalized cross-section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other characteristics, objectives and advantages of the present invention are described in greater detail below, and with reference to the accompanying drawings which illustrate nonrestrictive embodiments, and in which:

(2) FIGS. 1a, 1b and 1c are respectively schematic illustrations of a head-on view of a magnet structure containing a plurality of unitary magnets, an enlarged view of this magnet structure and a view in perspective of unitary magnets in the form of an elongated block according to a first embodiment of the present invention, the unitary magnets comprising at least a longitudinal end portion in an ovoid shape with inclined facets,

(3) FIGS. 2a, 2b and 2c are respectively schematic illustrations of a head-on view of a magnet structure containing a plurality of unitary magnets, an enlarged view of this magnet structure and a view in perspective of a unitary magnet in the form of an elongated block according to a second embodiment of the present invention, the unitary magnet comprising at least one longitudinal end portion in an ovoid shape with inclined facets, the inclined facets being rounded,

(4) FIGS. 3a, 3b and 3c are schematic representations respectively of a head-on view of a magnet structure containing a plurality of unitary magnets, an enlarged view of this magnet structure and a view in perspective of the unitary magnet in the form of an elongated block according to a third embodiment of the present invention, the unitary magnet having an essentially perfect ovoid shape with two rounded longitudinal and portions,

(5) FIG. 4 is a schematic illustration of a view in perspective of a magnet structure according to the present invention containing unitary magnets according to the second embodiment, unitary magnets being shown separately from the magnet structure to increase visibility,

(6) FIG. 5 is a schematic illustration of a view in perspective of a rotor comprising a plurality of magnet structures, the rotor being part of an electromagnetic actuator according to the present invention, the portion A inside the frame in this figure making reference to FIG. 4.

(7) The figures are given by way of examples and are not restrictive of the invention, they constitute schematic illustrations designed to facilitate an understanding of the invention and are not necessarily drawings to scale of practical applications. In particular, the dimensions of the different parts are not representative of reality.

(8) In the following, reference will be made to only a single unitary magnet, a single magnet structure, a single longitudinal facet, a single inclined facet and a single bevel for each type of bevel, however it must be understood that what is said with regard to one of these referenced elements is applicable to all similar elements.

(9) To be transverse to the unitary magnet means to be in a plane perpendicular to a longitudinal axis of the elongated unitary magnet having the form of a block.

DETAILED DESCRIPTION OF THE INVENTIONS

(10) With reference to all the figures and to FIGS. 1a to 1c, 2a to 2c and 3a to 3c in particular, the present invention relates to a unitary magnet 1 with an elongated shape that can be considered a block. “Elongated shape” means that its length is significantly greater than its width.

(11) The unitary magnet 1 has a contour that is at least partly ovoid. The unitary magnet 1 comprises a first portion 1a forming a body of the unitary magnet 1 having a larger cross-section and extending over a greater length of the unitary magnet 1 than at least a second longitudinal end portion 1b pointing toward an associated longitudinal extremity of the magnet, whereby its cross-section decreases as it approaches the longitudinal extremity.

(12) In FIG. 1c, the unitary magnet 1 comprises a single second end portion 1b. The first portion 1a and the second portion 1b of the unitary magnet 1 each comprise facets, longitudinal facets 3 for the first portion 1a and lateral facets 4 inclined toward the longitudinal extremity associated with the second portion 1b.

(13) In FIG. 2c, the unitary magnet comprises two second end portions 1b respectively for a longitudinal extremity of the unitary magnet 1. The first portion 1a and second portion 1b of the unitary magnet 1 each comprise facets, longitudinal facets 3 for the first portion 1a and facets 4 inclined toward the associated longitudinal extremity on the respective second portion 1b. In this embodiment, the inclined facets are rounded.

(14) In FIG. 3c, the unitary magnet 1 has an almost perfect ovoid shape with a first portion 1a and two second end portions 1b that are rounded and have a convex shape.

(15) With reference in particular to FIGS. 2c and 3c, at least one second longitudinal end portion 1b can be rounded and have a convex shape, with or without inclined facets 4. A crown of the convex shape can form the associated longitudinal extremity. It can be considered that the second end portion 1b in FIG. 1c has a convex shape with reference to the edges of the inclined facets 4.

(16) At least one second longitudinal end portion 1b has on its crown a median facet 5 forming the longitudinal extremity. This is the case in FIGS. 1c, 2c and 3c, although it is not mandatory.

(17) As shown in FIGS. 1c and 2c, at least a second longitudinal end portion 1b can comprise lateral facets 4 inclined toward a longitudinal axis of the magnet approaching the associated longitudinal extremity of the magnet. The inclined lateral facets 4 can extend between a large base 4a connected to the first portion 1a forming the body of the magnet and a small base forming one longitudinal extremity of the magnet, the median facet 5 then forming the small base.

(18) As shown in FIG. 2c, to somewhat more closely approximate an ovoid shape in spite of the presence of the inclined facets 4, the inclined lateral facets 4 can be rounded to give them a convex shape.

(19) FIGS. 2c and 3c show two second longitudinal end portions 1b on a respective longitudinal extremity of the unitary magnet 1.

(20) The first portion 1a forming the unitary magnet body 1 having a larger cross-section and extending over a greater length of the unitary magnet 1 can be rounded, having its largest cross-section toward a longitudinal median portion of the magnet and with a decreasing cross-section toward the longitudinal extremities of the magnet, to more closely approximate an ovoid shape. This is the case in FIG. 3c, although the case illustrated in FIG. 3c is not restrictive of this embodiment.

(21) As shown in FIGS. 1c and 2c for a polygonal shape with facets, the first portion 1a forming the body of the unitary magnet 1 can be in the shape of a polygon having longitudinal facets 3. As an alternative, the first portion 1a can have a cylindrical shape with a circular or ovalized cross-section.

(22) When the first portion 1a has longitudinal facets 3 and when one or both portions 1b have inclined facets 4, each of the inclined lateral facets 4 of the second portion or portions 1b is longitudinally extended on the unitary magnet 1 by a longitudinal facet 3 of the first portion 1a, one extremity of the inclined facet 4 of the second portion or portions 1b being placed end to end with one extremity of an associated longitudinal facet 3 of the first portion 1a.

(23) With reference in particular to FIGS. 1a, 1b, 2a, 2b, 3a, 3b, 4 and 5, the invention relates to a magnet structure 2 in three dimensions constituted by a plurality of unitary magnets 1. The patterns created by the unitary magnets 1 are different depending on the design of these unitary magnets 1.

(24) In this magnet structure 2, each unitary magnet 1 is of the type described above, the unitary magnets 1 being directly adjacent to one another and being partly in contact.

(25) The unitary magnets 1 are adhesively connected by the deposition of adhesive on the areas of the unitary magnets 1 in contact. It follows that the plurality of unitary magnets 1 forms a mesh structure of unitary magnets 1 without the interposition of retaining elements between them other than the adhesive, for example cells that each hold a unitary magnet 1.

(26) The unitary magnets 1 are in direct but partial contact between adjacent magnets. This is shown particularly clearly in FIG. 4 and in the enlarged FIGS. 1b, 2b and 3b.

(27) In one preferred embodiment of the present invention, the areas of the unitary magnets 1 in contact can have beveled edges 6, 6a hollowed out in an exterior contour of each unitary magnet 1 in contact with another unitary magnet 1, the adhesive being deposited exclusively on the beveled edges 6, 6a of the unitary magnets 1.

(28) The beveled edges 6 can be located on each of the ridges of the longitudinal facets 3 when present, located on the almost spot contact between two perfectly ovoid unitary magnets 1, or the beveled edges can be located on the large base 4a of the second portion 1b when the second portion 1b comprises inclined facets 4, which can be rounded or not.

(29) With particular reference to FIG. 5, the invention further relates to a linear or rotary electromagnetic actuator comprising a magnet structure 2 or a plurality of magnet structures 2 of the type described above where the magnet structure or structures 2 are part of a rotor 7 that rotates around its center as shown in FIG. 5 for an axial flux actuator. The magnet structure or structures 2 are arranged concentrically with respect to the center of the rotor 7, advantageously separated by branches 8 when there are a plurality of magnet structures 2 and framed on one hand by a hub 10 and a binding band 9. The branches 8 extend from the hub 10 and end at the binding band 9 that forms the external periphery of the rotor 7.

(30) The actuator illustrated in FIG. 5 is an axial flux actuator but can also be a radial flux actuator.

(31) When unitary, the magnet structure 2 can form a single magnet that extends over the actuator. When multiple, as illustrated in FIG. 5, the magnet structures 2 are successive blocks forming alternating successive magnetic poles.

(32) Finally, the invention relates to a method for the fabrication of a magnet structure 2 of the type described above. The method comprises a step of cutting out from a magnetized tile having a length, a width and a thickness forming the three dimensions of the tile a plurality of unitary magnets 1 according to the three dimensions of the magnetized tile, the unitary magnets 1 having at least partly an ovoid shape.

(33) The method then comprises a step of determining areas of partial contact on each unitary magnet 1 with each magnet that is adjacent to it when the magnets are adjacent to one another. The partial contact areas are a function of the external contour of the unitary magnets 1.

(34) The next step is the adhesive connection of each unitary magnet 1 by the application of a resin for each unitary magnet 1 only on the determined partial contact areas.

(35) The unitary magnets 1 are then positioned and adhesively connected in an adjacent matter to one another, partial contact between two adjacent unitary magnets 1 being established in the contact areas.

(36) A layer of composite can be injected around the unitary magnets 1 thus placed in contact and adhesively fastened to coat them and increase the density of the magnet structure 2 thus created.