Multipolar magnetization device for high-coercivity materials

Abstract

The magnetizing device (10) comprises a conductive portion (12) preferably made of copper, wherein the conductive portion (12) is prepared such that it forms a meandering pattern.

Description

Technical Field

[0001] The present invention relates to a magnetizing device that can be used to magnetize thin sheets or laminates in a multipolar pattern. The resulting magnetic pattern is a close implementation of a continuous Halbach array, with the magnetic field concentrated on the active side of the sheet or laminate and negligible stray fields on the other side. This multipolar stripe pattern also has the advantage of producing a strong magnetic retentive force perpendicular to the sheet or laminate and in the intra-sheet direction perpendicular to the stripes. Background Art

[0002] Producing this multipolar stripe pattern in high-energy-product permanent magnets with high coercivity, such as Nd-Fe-B, requires very high currents, which are discharged through a wire. The high current pulses make the design of such devices challenging for a number of reasons. The current generates high mechanical forces between the wire sections, which can cause the wire to bend. Therefore, the wire needs to be securely fixed in the device. Furthermore, to generate high currents in the device, high voltages must be applied. Therefore, the current needs to be well insulated from other components of the device to avoid voltage breakdown. In addition, high currents release a large amount of energy into the wire in the form of heat. Heating increases the resistance of the wire, thereby reducing the peak current. If not controlled, this can cause the wire to melt. Therefore, the heat must be extracted efficiently, which makes the fixing and insulation of the wire more challenging, thereby limiting the distance between the wire sections.

[0003] Current technology primarily uses conductors embedded in laminated iron blocks. Machining the blocks requires high precision, and care must be taken to ensure insulation when placing the conductors into the blocks. This places considerable technical limitations on how closely the conductor sections can be arranged together, as well as the minimum spacing of the multipolar stripe pattern. Summary of the Invention

[0004] It is therefore an object of the present invention to address these challenges and to provide a device that is easy to manufacture, easily adaptable to short inter-electrode distances, and capable of providing adequate electrical insulation while withstanding high thermal and mechanical stresses.

[0005] According to a first aspect of the present invention, this object is achieved by a magnetizing device comprising conductive portions, preferably made of copper, wherein the conductive portions are fabricated so as to form a zigzag pattern. In other words, each pair of adjacent conductive portions is connected at one end, thereby forming a zigzag pattern across the entire conductive portion. The connections between the conductive portions can be accomplished using conductive bridges. The zigzag pattern formed by the connected conductive portions represents the implementation of a zigzag current-carrying path. A zigzag path is herein defined as a path consisting of one or more substantially U-shaped curves formed by the conductive portions and, if present, conductive bridges. Thus, each conductive portion is connected to its two adjacent conductive portions. When current flows through the conductive portions in the zigzag path, a magnetic field is generated that can magnetize a thin sheet or laminate in a multipolar pattern very similar to a Halbach array. The magnetic field generated by the Halbach array-like stripe pattern is concentrated on one side of the thin sheet or laminate, while the stray field on the other side is negligible, resulting in a strong magnetic holding force perpendicular to the thin sheet or laminate and within the thin sheet perpendicular to the stripes.

[0006] The conductive parts of the magnetizing device are preferably separate pieces that are electrically connected to one another. This makes the magnetizing device easily scalable, allowing the number of conductive parts to be increased or decreased depending on the specific application. Furthermore, the device can be easily disassembled and reassembled, making it easy to transport.

[0007] In a preferred embodiment, the conductive segments are electrically connected via a conductive bridge, preferably a copper member with good electrical conductivity. Using a conductive bridge to connect two adjacent conductive segments further enhances the device's scalability. However, the conductive bridge is optional, as it can also be designed as part of the conductive segment. In fact, the magnetization device can also be manufactured as a single piece with a meandering pattern, where the conductive segments are integrally connected.

[0008] Preferably, the conductive portion is substantially plate-shaped or wedge-shaped. Plate-shaped conductive portions are primarily used in planar magnetization devices and are easier to stack and secure together, while wedge-shaped conductive portions are primarily used in arc-shaped or cylindrical magnetization devices to produce arc-shaped or cylindrical multipolar magnetic patterns. It should be noted that the term "plate" is not limited to flat plates or plates with flat surfaces. The same applies to the term "wedge," where the surface of the wedge does not have to be flat, convex, or concave. Any other geometric shape may also be employed, if appropriate. For example, a corrugated plate or a zigzag plate, instead of a flat plate, which produces a corrugated or zigzag stripe pattern rather than a straight stripe pattern, should also be considered "plate-shaped" within the scope of the present invention. The "plate-shaped" conductive portion preferably has a generally rectangular cross-section, wherein the two sides of the rectangle generally orthogonal to the stacking direction are longer than the other two sides of the rectangle generally parallel to the stacking direction. Furthermore, to achieve secure and stable stacking, the surfaces of the conductive portion orthogonal to the stacking direction are preferably prepared so that each two adjacent conductive portions provide sufficient surface contact area (taking into account electrical insulation between them, excluding the connection point).

[0009] Preferably, the conductive parts of the magnetization device are stacked and mechanically fixed together. Stacking the plate-shaped conductive parts creates a very modular and adaptable solution that can be easily scaled up. The high mechanical strength of the stacking and fixing, for example by glue, enables the device to withstand the high forces experienced during the magnetization process.

[0010] In a preferred embodiment, each conductive portion includes at least one through-hole. In another preferred embodiment, each conductive portion includes an open slot extending to one side of the conductive portion. In one embodiment, each conductive portion is provided with at least one through-hole and at least one open slot, with the at least one open slot extending from the at least one through-hole to one side of the conductive portion. The conductive portion including the through-hole is cut and prepared in such a manner that, as described above, current flowing through the conductive portion is confined to a layer as close as possible to the device surface, preferably opposite the side to which the at least one open slot extends. Furthermore, the at least one open slot extending to one side of the conductive portion helps prevent or reduce eddy currents. In particular, the at least one open slot extending from the through-hole to one side of the conductive portion prevents any eddy currents from flowing around the through-hole. Furthermore, the metal between the through-holes improves mechanical properties by securing the current-carrying layers in place. This metal also aids in heat dissipation by providing a path for heat to flow from the current-carrying layers, generated by Joule heating, to the opposite side of the conductive portion, where a larger amount of metal material is present to diffuse the heat, allowing for better and more efficient heat dissipation.

[0011] In a preferred embodiment, at least one insulating layer is provided between two adjacent conductive parts of the magnetizing device. This provides electrical insulation between the conductive parts and a means of mechanically securing the conductive parts together. The insulating layer is preferably a glue layer, wherein the glue layer is more preferably lined with fiberglass. The insulating layer is important for preventing electrical contact between the two conductive parts except at the connection points at the conductive bridge. The insulating layer preferably comprises an adhesive material (e.g., glue) to securely connect and secure the stacked conductive parts together, wherein the layer is preferably lined with fiberglass so that the specified thickness is maintained even under high pressure. The insulating layer is also preferably plate-shaped or wedge-shaped. However, it may also have any other shape that makes it suitable for stacking between the conductive parts.

[0012] More preferably, at least one field guide is provided between two adjacent conductive sections, preferably comprising iron. This field guide amplifies the magnetic field generated by the current and helps magnetize the sheet or laminate layer placed in a meandering pattern above the device. Like the conductive sections and insulating layer, the field guide is preferably plate-shaped or wedge-shaped. However, it may also take any other geometric shape suitable for stacking between the conductive sections and insulating layer.

[0013] At least one of the field guide portions preferably comprises at least one open slot extending to one side of the field guide portion.The field guide portions are cut in such a way as to reduce eddy currents but still have sufficient mechanical strength to be stacked together.

[0014] In a preferred embodiment, the magnetizing device further comprises a cooling device for further dissipating heat from the magnetizing device, wherein the cooling device can be based on liquid cooling, air cooling or any other cooling mechanism.

[0015] In a second aspect, the present invention also provides a method for magnetizing a layer, comprising: applying the layer to a meandering pattern of a magnetizing device according to the above-described method; and applying a current source to the magnetizing device so that the current flows through the meandering pattern. Using the magnetizing device and the method, the layer can be rapidly magnetized into a multipolar pattern, similar to the implementation of a Halbach array, but in a continuous manner rather than the more common use of discrete magnets, which significantly improves, for example, magnet assembly.

[0016] In a third aspect, the invention relates to a ski skin comprising a layer magnetized by the above method. With the integrated magnetized layer, the ski skin can be magnetically fixed to a ski base, which preferably also has a magnetic layer, thereby eliminating the need for glue for bonding.

[0017] In a fourth aspect, the invention discloses a snowboard base comprising a layer magnetized by the above method. In this way, a snowboard skin, which preferably also has a magnetic layer, can be magnetically fixed to the snowboard base.

[0018] In a fifth aspect, the present invention relates to a snowboard comprising a ski skin and a ski base, wherein the ski skin comprises a layer magnetized by the method according to the invention and / or the ski base comprises a layer magnetized by the method according to the invention, wherein the ski skin and the ski base are magnetically connected. It is up to the manufacturer to decide whether both the ski skin and the ski base are magnetized using the device and method according to the invention, or whether only one of them is magnetized in this manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The specific embodiments of the present invention are described below with reference to the accompanying drawings, wherein

[0020] Figure 1 shows a perspective exploded view of a planar magnetization device according to an embodiment of the present invention;

[0021] Figure 2 Shown according to Figure 1 A schematic side view of a conductive portion of a magnetizing device;

[0022] Figure 3 Shown Figure 1 A perspective view of a magnetizing device with an indication of the direction of current flow;

[0023] Figure 4 Shown Figure 1 A schematic cross-sectional view of a magnetizing device with an indicated current direction;

[0024] Figure 5 Shown according to Figure 4 Schematic diagram of the simulated magnetic field generated by the magnetization device;

[0025] Figure 6 Shown according to Figure 1 Schematic diagram of a planar magnetized device with stacked and fixed conductive parts;

[0026] Figure 7 shows a schematic diagram of a planar magnetization device with stacked and fixed conductive parts according to another embodiment of the present invention;

[0027] Figure 8 shows a schematic cross-sectional view of a cylindrical magnetization device according to an embodiment of the present invention;

[0028] Figure 9 A schematic diagram of a planar magnetization device having a wave-shaped conductive portion according to an embodiment of the present invention is shown;

[0029] Figure 10 A schematic diagram showing a ski base and ski skin secured by glue;

[0030] Figure 11A schematic diagram of a ski base and a ski skin is shown, both comprising a magnetic layer which is preferably magnetized by a magnetizing device according to the invention. DETAILED DESCRIPTION

[0031] Figure 1 FIG2 shows an exploded perspective view of a planar magnetization device 10 according to an embodiment of the present invention. The magnetization device 10 includes a plurality of conductive portions 12. The conductive portions 12 are fabricated such that each pair of adjacent conductive portions 12 are connected at one end, resulting in the entire conductive portion or device forming a zigzag pattern. The conductive portions 12 are preferably made of copper, which has good electrical conductivity.

[0032] In the following description, we will use Figure 1 The coordinate system shown is used to describe the planar magnetizer 10. The Z direction is referred to as the upper direction or the top direction, and the direction opposite to the Z direction is referred to as the lower direction or the bottom direction. Those skilled in the art will understand that such relative terms are used to clarify the description and do not limit the scope of the present invention to any particular direction.

[0033] according to Figure 1 In an embodiment, the conductive part 12 is a plate-shaped part extending along the X direction, wherein the conductive part 12 is preferably a separate electrically connected piece, preferably electrically connected through a plate-shaped conductive bridge 14, which is particularly a copper piece, wherein the conductive parts 12 are stacked one by one in the Y direction.

[0034] More specifically, Figure 2 As shown, each conductive portion 12 preferably includes one or more through-holes 16 and one or more open slots 18, wherein each open slot 18 preferably extends from one through-hole 16 to one side of the conductive portion 12. In particular, the open slots can extend in the Z direction to the underside of the conductive portion 12. The open slots 18 are used to prevent any eddy currents from flowing around the through-holes 16, while the through-holes 16 are cut to force the current to flow in the layers above the conductive portion 12. In addition, the metal between the through-holes 16 helps to hold the current-carrying layer in place, preventing it from bending due to the high current-induced forces. The metal between the through-holes 16 also helps dissipate heat because it provides a flow path for heat to flow from the current-carrying layer, which generates heat due to Joule heating, to the opposite underside of the conductive portion, where there is a large amount of metal material to spread the heat. This allows for better and more efficient heat dissipation.

[0035] Each conductive portion 12 preferably also includes at least one fastening hole 20 for fastening the stacked conductive portions. For example, two circular through-holes 20 are provided at each end of the conductive portion 12. The fastening holes 20 can accommodate rods, such as fiberglass rods, to secure the stacked conductive portions together. An open slot preferably extends from each fastening hole to one side of each conductive portion 12 to prevent or reduce eddy currents.

[0036] Each pair of adjacent conductive portions 12 is preferably separated by at least one insulating layer 22, so that no electrical connection is established other than the connection point formed by the conductive bridge 14. The insulating layer 22 is made of, for example, glue and is preferably lined with glass fiber so that it can maintain a set thickness even under high pressure. Each insulating layer 22 also includes at least one through-hole aligned with the fastening hole 20 for stacking and fixing purposes.

[0037] One or more field guides 24, preferably iron plates, may be positioned between two adjacent conductive portions 12 and insulated by an insulating layer 22. The field guides 24 amplify the magnetic field generated by the current and help magnetize the sheet or layer placed in a meandering pattern above the device. The metal layer 24 preferably also includes through-holes aligned with the fastening holes 20 for securing purposes. A plurality of open slots may be provided, preferably at locations distributed along the X direction and each extending along the Z direction to prevent eddy currents.

[0038] Figure 3 3 is an example diagram of the path of current generated by the device. The direction of current 32 is indicated by an arrow. As described above, the conductive portion is cut so that the current is confined to the layer on the upper surface of the device 10.

[0039] Figure 4 A schematic cross-sectional view of a magnetized device 10 with the current direction indicated is shown. Also shown is an upper layer 36 at the surface of the device 10 that carries the majority of the current 32. The magnetic field within the dashed box 34 generated by the current 32 was simulated by COMSOL software, as shown in FIG. Figure 5 shown.

[0040] like Figure 5 As shown, the circular field lines correspond to the magnetic field 40 generated by the current 32, reflecting the right-hand rule. A sheet or laminate 38 placed above the upper surface of the device 10 is magnetized by the magnetic field 40. Short arrows 42 represent the magnetic field at a specific height within the sheet or layer and show a cycloidal pattern, magnetizing the sheet or laminate 38 above the device 10 into a continuous Halbach array-like pattern. Figure 5 The pattern shown in is repeated throughout the device.

[0041] Figure 6 and Figure 7 Two embodiments of assembled planar magnetization devices are shown. Figure 6 The device 100 is shown, comprising a stacked conductive portion 112 made of copper, a conductive bridge 114 made of copper, an insulating layer 122, and a field guide 124 made of iron. The high mechanical strength of the stack and the glue enables the device 100 to withstand the large forces experienced during the magnetization process. At least one rod, preferably two fiberglass rods 140, are inserted through aligned fastening holes and other aligned holes at the ends of the conductive portion 112, the conductive bridge 114, the insulating layer 122, and the field guide 124 to create a rigid structure and prevent the stack from bending when compressed.

[0042] To construct the device 100, the conductive part 112 and the other parts are preferably cut from a sheet of corresponding thickness and material by electro-etching or other methods such as laser cutting. The parts 112 are then stacked together and aligned along the rod 140. Once the stacking is complete, the stack can be squeezed and fixed together, for example, by screws 142, and the glue can be cured in an oven at about 120°C for 3-4 hours. After the glue is cured, the stack is able to withstand the high pressure applied to it. A sufficiently high pressure is then applied to prevent the device from delamination, which also helps to form good contact between the conductive part 112 and the conductive bridge 114 forming the current path. The device is realized with, for example, a copper part with a thickness of 1.5 mm and an iron layer with a thickness of 1.5 mm, resulting in a pole pitch of about 3.4 mm.

[0043] To increase the pole density, the present invention can be adapted by removing the iron layer completely. Figure 7 As shown, such a device 200 comprises only a conductive portion 212, a conductive bridge 214, and an insulating layer 222, which also serves as a spacer to set the pole width. Thus, the pole density can be significantly increased without sacrificing structural properties. However, due to the close distance between the poles, a higher current must be introduced to fully magnetize a thin sheet of a certain thickness. An implementation of such a device 200 without field guides has, for example, a conductive portion with a thickness of 1.5 mm and a pole pitch of 1.8 mm.

[0044] By using wedge-shaped conductive parts instead of plate-shaped parts, the device can also be easily adapted to arc-shaped or cylindrical designs. Figure 8 A cross-sectional view of such a device 300 is shown, comprising a wedge-shaped conductive portion 312, preferably made of copper, an insulating layer 322 (e.g., made of glue), and a field guide, preferably made of iron. The wedge-shaped conductive portion 312 is preferably cut so that the current 332 is confined to a layer 336 as close as possible to the inner surface of the device 300. An arc-shaped layer or columnar layer 338 is placed along the inner surface of the device 300 and can be magnetized into a multi-pole pattern, which is an approximate realization of a continuous circular Halbach array.

[0045] It should be noted that the plate-shaped conductive portion of the magnetizing device is not limited to Figure 6and Figure 7 The flat plate or rectangular plate shape shown in FIG. Instead, other more complex geometric shapes can also be obtained and used. Similarly, the wedge-shaped conductive portion of the magnetizing device is not limited to the following. Figure 8 The wedges shown may have flat, convex or concave surfaces. They may also have any geometric shape.

[0046] For example, Figure 9 Another embodiment of the device 100' is shown, which can be used to produce a wavy or zigzag stripe pattern, wherein each conductive portion 112' is shaped as a wavy plate or a zigzag plate. In addition, each field guide portion 124' and each insulating layer 122' are also correspondingly shaped as a wavy plate or a zigzag plate. The forming process can be achieved by pressing each conductive plate 112' with a corresponding mold before stacking, so that the conductive plate 112' takes the shape of the mold. Depending on the application, the conductive plate 112' can also be formed into other plate shapes using other suitable molds. The same forming process is also applicable to the field guide portion 124' and the insulating layer 122', so that they can be stacked together with the conductive portion 122' and the conductive bridge 114' (if present) to construct the device 100', preferably using a fiberglass rod 140'. After stacking, they are preferably further squeezed and firmly fixed together by screws 142'.

[0047] The magnetizing device according to the invention can be used to magnetize thin sheets or layers of any magnetizable material, preferably 0.1 to 1 mm. An example is a ski skin or ski base comprising a layer magnetized by the device according to the invention.

[0048] Figure 10 Shown is a conventionally connected ski skin 450 and ski base 460. The ski skin 450 is typically constructed of layers of different materials, namely a layer 451 in contact with the snow (e.g. made of velvet), a layer 453 in contact with the ski, preferably made of rubber, and some other structural layers 452 in between, such as Figure 10 The adhesive layer 470 above the rubber layer 453 is generally used to secure the snowboard skin 450 to the snowboard base 460 .

[0049] According to this application, if Figure 11 As shown, glue is no longer needed to secure the ski skin 550. Instead of glue, magnetizable particles are mixed directly into the rubber layer 553. Depending on the model, other materials such as silicone can be used instead of rubber. In models with silicone, the magnetizable particles are then mixed directly into the silicone. Since there is no glue, magnetic force is used to secure the ski skin 550 to the ski base 560.

[0050] During production, the magnetizable particles are randomly oriented and have randomly oriented grains. Therefore, they do not generate any significant magnetic field. The magnetizing device according to the present invention is capable of generating a magnetic field of approximately 2 Tesla, which is capable of saturating the magnetic particles, which will permanently retain a portion of this magnetization within the rubber layer 553 of the snowboard skin 550. The rubber layer 553 can thus be magnetized by the device into a nearly continuous Halbach array, which provides significant magnetic force within the layer in a direction perpendicular to the surface of the rubber layer 553 and in a direction perpendicular to the stripes.

[0051] To secure the ski skin 550 to the ski base 560, a similar magnetic layer 562 can also be incorporated into the ski base 560. The ski base 560 is typically made of a 1.2 mm thick HDPE layer. A thin HDPE layer can be mixed with magnetizable particles and integrated into the HDPE layer of the ski base 560, creating a three-layer sandwich within the ski base 560. The first layer 561 is a pure HDPE layer for gliding, the second layer 562 is a magnetic HDPE layer for securing, and the third layer 563 is made of pure HDPE to achieve a thickness of 1.2 mm without adding too much extra weight. The ski base's magnetic layer 562 can be magnetized using the same device used for the ski base. However, whether to use the device to magnetize both the ski skin and the ski base, or just one of them, is up to the manufacturer or a skilled artisan.

[0052] However, the magnetizing device according to the invention is not limited to the magnetization of ski skins and ski bases, but can be applied to anything that uses sheets or layers of magnetizable materials such as Nd-Fe-B. For example, it can be used to magnetize sheets for fastening purposes, such as fastening a mobile phone to a docking station, or flat refrigerator magnets are also conceivable. Along this line, another application is to apply magnetizable particles to textiles and magnetize them by means of the device according to the invention, so that the magnetic force can be used to close or tighten clothing instead of using buttons or zippers. With regard to e.g. Figure 8 The cylindrical embodiment shown, the device according to the invention can also be used to produce an approximate Halbach array in the stator of an electric motor (eg a stepper motor), wherein magnetizing the circular stator into a continuous multipole pattern would significantly simplify the assembly of the stator.

Claims

1. A magnetizing device (10, 100, 200, 300, 100'), comprising a conductive portion (12, 112, 212, 312, 112'), wherein: The conductive portion (12, 112, 212, 312, 112') is prepared so that it forms a meandering pattern, Each conductive portion (12, 112, 212, 312, 112') includes at least one through hole (20). Each conductive portion (12, 112, 212, 312, 112') includes at least one open slot (18) extending to one side of the conductive portion. wherein at least one of the opening slots (18) extends from at least one of the through holes (20) to one side of the conductive portion, and Wherein, the conductive portion (12, 112, 212, 312, 112') is plate-shaped or wedge-shaped, At least one insulating layer (22, 122, 222, 322, 122') is provided between two adjacent conductive parts (12, 112, 212, 312, 112'), wherein the insulating layer (22, 122, 222, 322, 122') is a glue layer, so that the conductive parts (12, 112, 212, 312, 112') are stacked and mechanically fixed together by glue, wherein the glue layer is lined with glass fiber.

2. The magnetization device (10, 100, 200, 300, 100') according to claim 1, characterized in that The conductive parts (12, 112, 212, 312, 112') are separate pieces electrically connected to each other.

3. The magnetization device (10, 100, 200, 300, 100') according to claim 2, characterized in that The conductive parts (12, 112, 212, 312, 112') are electrically connected via a conductive bridge (14, 114, 214, 114').

4. The magnetization device (10, 100, 200, 300, 100') according to claim 3, wherein: The conductive bridge is a copper piece.

5. The magnetization device according to claim 1, characterized in that At least one field guide portion (24, 124, 324, 124') is arranged between two adjacent conductive portions (12, 112, 312, 112').

6. The magnetization device according to claim 5, wherein The field guide portion includes iron.

7. The magnetization device according to claim 5, wherein: At least one of the field guide portions (24, 124, 324, 124') includes at least one open slot extending to one side of the field guide portion.

8. The magnetization device according to any one of claims 1 to 7, characterized in that The magnetizing device further comprises a cooling device.

9. A method of magnetizing a layer, comprising: applying said layer at said meandering pattern of a magnetizing device (10, 100, 200, 300, 100') according to any one of claims 1 to 8; A current source is applied to the magnetizing device (10, 100, 200, 300, 100') to cause current to flow through the meandering pattern.

10. A snowboard skin comprising a layer magnetized by the method according to claim 9.

11. A snowboard base (560) comprising a layer magnetized by the method according to claim 9.

12. A snowboard comprising a snowboard skin and a snowboard base (560), wherein: The ski skin comprises a layer magnetized by the method according to claim 9 and / or the ski base (560) comprises a layer magnetized by the method according to claim 9, wherein the ski skin and the ski base (560) are magnetically connected.

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