Magnetic core, electrical equipment and preparation method of magnetic core

Abstract

The invention relates to the technical field of magnetic core preparation, and provides a magnetic core, electrical equipment and a preparation method of the magnetic core, and the magnetic core comprises at least two layers of magnetic sheets and a bonding layer. And the at least two layers of magnetic sheets are laminated. A bonding layer is arranged between any two adjacent magnetic sheets; the magnetic core has a cut surface, the flatness Fl of the cut surface is less than or equal to 2 [mu] m, and the roughness Rz of the cut surface is less than or equal to 1 [mu] m; all the magnetic sheets and all the adhesive layers intersect with the cut surface. Therefore, the magnetic core shows the characteristic of magnetic anisotropy, and then the magnetic conductivity has different values in different directions. And the magnetic conductivity is higher in the easy magnetization direction, so that the magnetic conductivity of the magnetic core can be improved by utilizing the easy magnetization direction of the magnetic core. In addition, hysteresis loss and eddy-current loss of the magnetic core can be reduced. After the cut-off surfaces of the two magnetic cores abut against each other, the width of the gap between the two cut-off surfaces can meet the installation requirement of the magnetic cores, and therefore the standard of the appearance of the cut-off surfaces of the magnetic cores can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic core preparation, in particular to a magnetic core, an electrical device and a preparation method of the magnetic core. BACKGROUND

[0002] The magnetic core formed by winding amorphous or nanocrystalline strip is widely used in the fields of precision current transformers, high-end common-mode inductors and high-frequency power transformers.

[0003] In the prior art, the magnetic core used for being mounted on the electric drive filtering product with a bent copper bar or a complex plastic shell structure and the power transformer is usually obtained by cutting an initial magnetic core with different shapes.

[0004] However, the magnetic core obtained by cutting has low permeability and high hysteresis loss and eddy current loss. In addition, the cutting surface of the magnetic core obtained by cutting has burrs and laminated traces, that is, the appearance of the cutting surface is poor. SUMMARY

[0005] The present application provides a magnetic core, an electrical device and a preparation method of the magnetic core, which improves the permeability, reduces the hysteresis loss and eddy current loss by setting a laminated structure. The flatness and roughness of the cutting surface of the magnetic core are limited to meet the standard of the appearance of the cutting surface of the magnetic core.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a magnetic core, comprising: at least two layers of magnetic sheets and an adhesive layer. The at least two layers of magnetic sheets are laminated. The adhesive layer is arranged between any two adjacent magnetic sheets; the magnetic core has a cutting surface, the flatness Fl of the cutting surface is ≤20μm, the roughness Rz of the cutting surface is ≤10μm; all the magnetic sheets and all the layers intersect with the cutting surface.

[0008] As an optional implementation, the flatness Fl of the cutting surface is ≤2μm, and the roughness Rz of the cutting surface is ≤1μm.

[0009] As an optional implementation, the flatness Fl of the cutting surface is ≤0.5μm, and the roughness Rz of the cutting surface is ≤0.1μm.

[0010] As an optional implementation, the magnetic sheet is an amorphous or nanocrystalline strip, and the thickness H1 of the amorphous or nanocrystalline strip is in the range of 5μm≤H1≤30μm.

[0011] As an optional implementation, the filling coefficient K of the magnetic core formed by the magnetic sheets is in the range of K≥0.6; the ratio of the actual mass of the magnetic core to the theoretical mass of the magnetic core is the filling coefficient K.

[0012] As an optional implementation, K≥0.7.

[0013] As an optional implementation, K≥0.8.

[0014] As an optional implementation, the magnetic sheet is made of amorphous alloy strips, the thickness H1 is in the range of 20μm≤H1≤30μm, preferably 23μm≤H1≤28μm; the filling coefficient K is in the range of 0.8≤K≤0.9; the ratio of the actual mass of the magnetic core to the theoretical mass of the magnetic core is the filling coefficient K.

[0015] As an optional implementation, the magnetic sheet is made of nanocrystalline alloy strips, the thickness H1 of the magnetic sheet is in the range of 10μm≤H1≤18μm, preferably 12μm≤H1≤16μm; the filling coefficient K is in the range of 0.8≤K≤0.9; the ratio of the actual mass of the magnetic core to the theoretical mass of the magnetic core is the filling coefficient K.

[0016] As an optional implementation, on the cut surface, the cross sections of part of the magnetic sheets are connected to each other to form a bonding surface.

[0017] On the cut surface, the ratio of the sum of the areas of all the bonding surfaces to the area of the cut surface is a bonding area ratio α; the bonding area ratio α is in the range of α≤0.95.

[0018] As an optional implementation, the bonding area ratio α is in the range of α≤0.5, and further preferably α≤0.1.

[0019] The number of the cut surfaces is at least two; the cut surfaces intersect with the tangent plane in which the magnetic sheet is located.

[0020] As an optional implementation, the magnetic core comprises a first straight line segment, a circular arc segment and a second straight line segment; along the extension direction of the magnetic sheet, the first straight line segment, the circular arc segment and the second straight line segment are connected in sequence; the concave surface of the circular arc segment faces the first straight line segment.

[0021] The axis of the first straight line segment and the axis of the second straight line segment are parallel.

[0022] As an optional implementation, the magnetic core is a special-shaped magnetic core.

[0023] As an optional implementation, the magnetic core is a C-shaped, square, prism-shaped, E-shaped, U-shaped or I-shaped magnetic core.

[0024] In a second aspect, the present application provides an electrical device, which comprises the magnetic core of any one of the first aspect.

[0025] In a third aspect, the present application provides a method for manufacturing a magnetic core, which is used for manufacturing the magnetic core of any one of the first aspect, and the method comprises:

[0026] Step 1, a magnetic sheet is used to form a magnet, the magnet has at least two layers of the magnetic sheet, and the at least two layers of the magnetic sheet are stacked;

[0027] Step 2, the magnet is bonded and cured by an adhesive to form a whole;

[0028] Step 3, the cured magnet is cut to obtain the magnetic core, and the cutting surface intersects with a tangent plane of the magnetic sheet.

[0029] As an optional implementation, the method for manufacturing the magnetic core further comprises Step 4, polishing the cutting surface of the magnetic core.

[0030] As an optional implementation, the method for forming the magnet by the magnetic sheet further comprises: the magnetic sheet is stacked layer by layer to form the magnet.

[0031] As an optional implementation, the method for manufacturing the magnetic core further comprises: between Step 1 and Step 2, a magnetic field is applied to the magnet; or,

[0032] Between Step 1 and Step 2, the magnet is subjected to heat treatment in a non-magnetic field environment.

[0033] In a fourth aspect, the present application provides a method for manufacturing a magnetic core, which is used for manufacturing the magnetic core of any one of the first aspect, and the method comprises:

[0034] A liquid adhesive is coated on the surface of the magnetic sheet;

[0035] The magnetic sheet is wound to form a magnet, wherein the magnet has at least two layers of the magnetic sheet, and the at least two layers of the magnetic sheet are stacked, and the adjacent magnetic sheets are filled with the liquid adhesive, and the adhesive is cured;

[0036] The magnet with the cured adhesive in the filling gap is cut to obtain the magnetic core, wherein the cutting surface of the magnetic core intersects with a plane where the magnetic sheet is located;

[0037] polishing the cut surface of the magnetic core.

[0038] As an optional implementation, the method of forming the magnetic body from the magnetic sheets further comprises: stacking the magnetic sheets layer by layer to form the magnetic body.

[0039] As an optional implementation, a magnetic field is applied to the magnetic body before the magnetic body is cut; or, the magnetic body is heat treated in a magnetic-free environment.

[0040] In a fifth aspect, the present application provides a method for preparing a magnetic core, the method being used to prepare the magnetic core of any one of the first aspect, the method comprising:

[0041] stacking the magnetic sheets to form a magnetic body, the magnetic body having at least two layers of the magnetic sheets, the at least two layers of the magnetic sheets being stacked; and the adjacent magnetic sheets having a filling gap therebetween;

[0042] applying a magnetic field to the magnetic body; or, heat treating the magnetic body in a magnetic-free environment;

[0043] spraying a liquid adhesive to the surface of the magnetic body to fill the filling gap with the liquid adhesive and solidify the liquid adhesive into a whole;

[0044] cutting the magnetic body having the adhesive sprayed to and solidified on the surface to obtain the magnetic core, the cut surface of the magnetic core intersecting with the tangent plane of the magnetic sheet;

[0045] polishing the cut surface of the magnetic core.

[0046] As an optional implementation, the method of forming the magnetic body from the magnetic sheets further comprises: winding the magnetic sheets to form the magnetic body.

[0047] As an optional implementation, the step of spraying the liquid adhesive to the surface of the magnetic body and solidifying the liquid adhesive into a whole comprises: heat treating the magnetic body to solidify the liquid adhesive.

[0048] In a sixth aspect, the present application provides a method for preparing a magnetic core, the method being used to prepare the magnetic core of any one of the first aspect, the method comprising:

[0049] stacking the magnetic sheets to form a magnetic body, the magnetic body having at least two layers of the magnetic sheets, the at least two layers of the magnetic sheets being stacked; and the adjacent magnetic sheets having a filling gap therebetween;

[0050] applying a magnetic field to the magnetic body; or, heat treating the magnetic body in a magnetic-free environment;

[0051] injecting high polymer plastics into the filling gap by using injection equipment and solidifying and bonding into a whole;

[0052] cutting the magnet after injection to obtain the magnetic core; wherein the cutting surface of the magnetic core intersects with the tangent plane of the magnetic sheet;

[0053] polishing the cutting surface of the magnetic core.

[0054] As an optional implementation, the way of forming the magnetic sheet into a magnet further comprises: making the magnetic sheet into a magnet in a winding manner.

[0055] Compared with the prior art, the application has at least the following beneficial effects:

[0056] Since the magnetic core comprises at least two layers of magnetic sheets and a bonding layer, the at least two layers of magnetic sheets are stacked, so that in the magnetic core, the direction parallel to the plane of the magnetic sheet is the easy magnetization direction, and the direction perpendicular to the plane of the magnetic sheet is the hard magnetization direction, that is, the magnetic core exhibits the characteristic of magnetic anisotropy. Further, it will result in different values of magnetic permeability in different directions. The magnetic permeability is higher in the easy magnetization direction, and the magnetic permeability is lower in the hard magnetization direction. Thus, in specific applications, the easy magnetization direction of the magnetic core can be used to improve the magnetic permeability of the magnetic core.

[0057] The magnetic anisotropy characteristic exhibited by the above-mentioned magnetic core will also affect the motion of the magnetic domain wall and the flipping process of the magnetic moment. Specifically, in the easy magnetization direction, the motion of the magnetic domain wall and the flipping of the magnetic moment do not need to overcome a large energy barrier, so as to reduce the magnetic hysteresis loss and eddy current loss of the magnetic core.

[0058] Since the magnetic core has a cutting surface, the flatness Fl of the cutting surface is ≤20 μm, the roughness Rz of the cutting surface is ≤10 μm; all the magnetic sheets and all the bonding layers intersect with the cutting surface. Thus, after the cutting surfaces of two magnetic cores are abutted, the gap width between the two cutting surfaces can meet the requirements of the installation of the magnetic core. Further, the standard of the appearance of the cutting surface morphology of the magnetic core can be reached. BRIEF DESCRIPTION OF DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0060] Figure 1 A structural schematic diagram of a magnetic core provided by the embodiments of the present application;

[0061] Figure 2 for Figure 1 Top view of the middle magnetic core;

[0062] Figure 3 This is a schematic diagram of the structure of a magnet formed by winding.

[0063] Figure 4 A flowchart illustrating a method for fabricating a magnetic core, as provided in an embodiment of this application;

[0064] Figure 5 A flowchart illustrating another method for preparing a magnetic core, as provided in an embodiment of this application;

[0065] Figure 6 A flowchart illustrating another method for preparing a magnetic core, as provided in this application embodiment;

[0066] Figure 7 A flowchart illustrating another method for preparing a magnetic core, provided as an embodiment of this application.

[0067] Explanation of reference numerals in the attached figures:

[0068] 100 - Magnetic core, 110 - Magnetic sheet, 120 - Adhesive layer, 130 - Cut surface

[0069] 200-Magnet. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0071] The magnetic cores obtained through cutting have low permeability and high hysteresis and eddy current losses. In addition, the cut surfaces of the magnetic cores obtained through cutting have burrs and stacking marks, that is, the appearance of the cut surfaces is poor.

[0072] When two magnetic cores meet at their cut surfaces, uneven cut surfaces can easily lead to larger gaps, causing a decrease in the overall inductance of the magnetic core. If the roughness is too large, it can cause stray fields or poor contact at the cut surfaces, resulting in a decrease in resistivity and an increase in eddy current losses.

[0073] To address the aforementioned technical problems, the magnetic core provided by this invention solves the issues of low permeability and high hysteresis and eddy current losses by configuring the core as a stacked structure. Furthermore, it addresses the problem of poor surface appearance of the core's cut surface by limiting its flatness and roughness.

[0074] Specifically, the magnetic core comprises at least two magnetic sheets and an adhesive layer, with the at least two magnetic sheets stacked together. In this core, the direction parallel to the plane of the magnetic sheets is the easy magnetization direction, and the direction perpendicular to the plane of the magnetic sheets is the difficult magnetization direction. This means the magnetic core exhibits magnetic anisotropy, resulting in different permeability values ​​in different directions. The permeability is higher in the easy magnetization direction and lower in the difficult magnetization direction. Therefore, in practical applications, utilizing the easy magnetization direction of the core can increase its permeability.

[0075] The magnetic anisotropy exhibited by the aforementioned magnetic core also affects the movement of domain walls and the reversal of magnetic moments. Specifically, in the easy magnetization direction, the movement of domain walls and the reversal of magnetic moments do not require overcoming a large energy barrier, thus reducing the hysteresis loss and eddy current loss of the magnetic core.

[0076] Because the magnetic core has a cut surface with a flatness Fl ≤ 20 μm and a roughness Rz ≤ 10 μm, and all magnetic sheets and layers intersect with the cut surface, the gap width between the two cut surfaces after they are brought together meets the requirements for magnetic core installation. This achieves the standard for the appearance of the magnetic core's cut surface.

[0077] The contents of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can have a clearer and more detailed understanding of the contents of this application.

[0078] The following provides a detailed description of the specific structure of the magnetic core and various possible implementation methods.

[0079] Figure 1 This is a schematic diagram of the structure of a magnetic core 100 provided in an embodiment of this application. Figure 2 for Figure 1 Top view of the middle magnetic core 100 Figure 3 This is a schematic diagram of the structure of the wound magnet 200.

[0080] See Figure 1 , Figure 2 and Figure 3 The magnetic core 100 includes at least two magnetic sheets 110 and an adhesive layer 120. The at least two magnetic sheets 110 are stacked. The two magnetic sheets 110 are bonded together by the adhesive layer 120. An adhesive layer 120 is provided between any two adjacent magnetic sheets 110.

[0081] The magnetic core 100 has a cut surface 130, the flatness of the cut surface 130 is Fl≤20μm, and the roughness of the cut surface 130 is Rz≤10μm; all magnetic sheets 110 and all adhesive layers 120 intersect with the cut surface 130.

[0082] In this embodiment, the magnetic core 100 includes at least two magnetic sheets 110 and an adhesive layer 120. The at least two magnetic sheets 110 are stacked, and an adhesive layer 120 is provided between any two adjacent magnetic sheets 110. Thus, in the magnetic core 100, the direction parallel to the plane containing the magnetic sheets 110 is the easy magnetization direction, and the direction perpendicular to the plane containing the magnetic sheets 110 is the difficult magnetization direction. That is, the magnetic core 100 exhibits magnetic anisotropy. This results in different values ​​of permeability in different directions. The permeability is higher in the easy magnetization direction and lower in the difficult magnetization direction. Therefore, in practical applications, the permeability of the magnetic core 100 can be increased by utilizing the easy magnetization direction of the magnetic core 100.

[0083] The magnetic anisotropy exhibited by the magnetic core 100 also affects the movement of domain walls and the reversal of magnetic moments. Specifically, in the easy magnetization direction, the movement of domain walls and the reversal of magnetic moments do not require overcoming a large energy barrier, thus reducing the hysteresis loss and eddy current loss of the magnetic core 100.

[0084] Because the magnetic core 100 has a cut surface 130, the flatness Fl of the cut surface 130 is ≤20μm, and the roughness Rz of the cut surface 130 is ≤1μm; all magnetic sheets 110 and all adhesive layers 120 intersect with the cut surface 130. Thus, after the cut surfaces 130 of two magnetic cores 100 are brought together, the gap width between the two cut surfaces 130 can meet the installation requirements of the magnetic core 100. This achieves the standard for the morphological appearance of the cut surface 130 of the magnetic core 100.

[0085] It should be noted that the shape of the magnetic core 100 can be plate-shaped, straight strip-shaped, or curved strip-shaped, or a strip-shaped combination of straight and curved lines. This application embodiment does not limit this. The magnetic core 100 is obtained by cutting other magnets, and a cut surface 130 of the magnetic core 100 is formed at the cut surface.

[0086] As an optional implementation, the flatness Fl of the cut surface 130 is ≤2μm, and the roughness Rz of the cut surface 130 is ≤1μm.

[0087] As an alternative implementation, see Figure 1 and Figure 2 The flatness of the cut surface 130 is Fl≤0.5μm, and the roughness of the cut surface 130 is Rz≤0.1μm.

[0088] When the cut surface 130 of the magnetic core 100 meets the above-mentioned requirements for flatness and roughness, the gap width between the two cut surfaces 130 after they are brought together is less than 0.1 μm. This further facilitates the installation of the magnetic core 100 and thus further meets the morphological appearance standards of the cut surface 130. At this time, the cut surface 130 achieves a mirror effect.

[0089] When the magnetic core 100 meets all the above technical characteristics, after testing, the gap width between the two cut surfaces 130 of the magnetic core 100 is less than 0.1 μm after being brought together by pressing and splicing with a force of 125 kg, the magnetic permeability of the magnetic core 100 is greater than 1000 (100 kHz, 0.3 T), and the hysteresis loss and eddy current loss are both less than 100 W / kg (20 kHz, 0.5 T).

[0090] It should be noted that the flatness mentioned above refers to the maximum permissible deviation between the actual surface of the object and the ideal plane, indicating the magnitude of the surface ripples. The roughness mentioned above refers to the distance between the peak line and the valley line of the profile within the sampling length of the object, indicating the density of the surface ripples.

[0091] As an alternative implementation, see Figure 1 , Figure 2 and Figure 7 The thickness H1 of the magnetic sheet 110 has a range of 5μm≤H1≤30μm.

[0092] As an optional implementation, the fill factor K of the magnetic core composed of magnetic sheet 110 is in the range of K ≥ 0.6. The fill factor K is the ratio of the actual mass of the magnetic core 100 to the theoretical mass of the magnetic core 100.

[0093] In some possible implementations, K ≥ 0.7.

[0094] In some possible implementations, K ≥ 0.8.

[0095] In this embodiment, the actual mass of the magnetic core 100 is the mass obtained by weighing a magnetic core 100 of a certain length. The theoretical mass of the magnetic core 100 is the mass obtained by theoretical calculation of a magnetic core 100 of the same length.

[0096] The magnetic sheet 110 can be an amorphous or nanocrystalline ribbon. Because amorphous or nanocrystalline materials possess the characteristics of high saturation magnetization, high permeability, and low loss, they exhibit excellent overall soft magnetic properties, especially good high-frequency performance. Therefore, using amorphous or nanocrystalline materials as the material for the magnetic sheet 110 can further improve the permeability of the magnetic core 100 and further reduce the hysteresis loss and eddy current loss of the magnetic core 100. For example, setting the magnetic sheet 110 in a ribbon shape facilitates winding the magnetic sheet 110 to form the magnet 200.

[0097] Experiments have shown that when the thickness H1 of the amorphous or nanocrystalline ribbon is in the range of 5μm≤H1≤30μm, and the filling coefficient K of the amorphous or nanocrystalline ribbon is in the range of K≥0.7, the permeability of the magnetic core 100 can be further improved, and the hysteresis loss and eddy current loss of the magnetic core 100 can be further reduced.

[0098] As an alternative implementation, see Figure 1 and Figure 2 When the magnetic sheet 110 is made of amorphous alloy strip, the thickness H1 of the magnetic sheet 110 is in the range of 20μm≤H1≤30μm; preferably, 23μm≤H1≤28μm.

[0099] The filling factor K of magnetic sheet 110 has a range of values: 0.8≤K≤0.9.

[0100] Experiments have shown that, based on the conditions of 5μm≤H1≤30μm and K≥0.7, when the magnetic sheet 110 is made of amorphous alloy strip, the thickness H1 of the magnetic sheet 110 is in the range of 20μm≤H1≤30μm, and the filling coefficient K of the magnetic sheet 110 is in the range of 0.8≤K≤0.9, this is the first preferred solution. Adopting this first preferred solution can further improve the permeability of the magnetic core 100 and further reduce the hysteresis loss and eddy current loss of the magnetic core 100.

[0101] As an optional implementation, the magnetic sheet 110 is made of nanocrystalline alloy strip, and the thickness H1 of the magnetic sheet 110 ranges from 10μm to 18μm. Preferably, it is 12μm to 16μm.

[0102] For example, the value of thickness H1 can be 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, etc.

[0103] The filling factor K of magnetic sheet 110 has a range of values: 0.8≤K≤0.9.

[0104] Experiments have shown that, based on the conditions of 5μm≤H1≤30μm and K≥0.7, the second preferred solution is achieved when the magnetic sheet 110 is made of nanocrystalline alloy strip, the thickness H1 of the magnetic sheet 110 is in the range of 12μm≤H1≤16μm, and the filling coefficient K of the magnetic sheet 110 is in the range of 0.8≤K≤0.9. Adopting the second preferred solution can further improve the permeability of the magnetic core 100 and further reduce the hysteresis loss and eddy current loss of the magnetic core 100.

[0105] As an alternative implementation, in some embodiments, see [link to documentation]. Figure 1 and Figure 2 On the cut surface 130, the cross sections of some magnetic sheets 110 are interconnected to form an adhesive surface. On the cut surface 130, the ratio of the sum of the areas of all adhesive surfaces to the area of ​​the cut surface 130 is the adhesive area ratio α; the value of the adhesive area ratio α is in the range of α≤0.95.

[0106] Since the magnetic core 100 is obtained by cutting other magnets, a cut surface 130 of the magnetic core 100 is formed at the cut surface. During the cutting operation, metal melts at a portion of the cross-section of the magnetic sheet 110, so that the cross-sections of adjacent magnetic sheets 110 are connected to each other to form an adhesive surface.

[0107] Experiments have shown that when the adhesion area ratio α is within the range of α≤0.95 on the cut surface 130, the permeability of the magnetic core 100 can be further improved, and the hysteresis loss and eddy current loss of the magnetic core 100 can be further reduced.

[0108] As an optional implementation, in some embodiments, the value range of the adhesion area ratio α is: α≤0.5, and more preferably α≤0.1.

[0109] Experiments have shown that, based on α≤0.95, when the bonding area ratio α is in the range of α≤0.5, the permeability of the magnetic core 100 can be further improved, and the hysteresis loss and eddy current loss of the magnetic core 100 can also be further reduced.

[0110] Among them, the smaller the adhesion area ratio α, the more beneficial it is to improve the permeability of the magnetic core 100 and reduce the hysteresis loss and eddy current loss of the magnetic core 100.

[0111] As an optional implementation, the magnetic sheet 110 is an amorphous or nanocrystalline ribbon, all of which extend in the same direction; the extension direction of the amorphous or nanocrystalline ribbon is perpendicular to the stacking direction of the amorphous or nanocrystalline ribbon. There are two cut surfaces 130; along the extension direction of the amorphous or nanocrystalline ribbon, the two cut surfaces 130 are located at both ends of the amorphous or nanocrystalline ribbon, and the two cut surfaces 130 are perpendicular to the plane containing the amorphous or nanocrystalline ribbon.

[0112] In this embodiment, amorphous or nanocrystalline materials possess the characteristics of high saturation magnetic induction, high permeability, and low loss, exhibiting excellent comprehensive soft magnetic properties, especially good high-frequency performance. Therefore, using amorphous or nanocrystalline materials as the material of the magnetic sheet 110 can further improve the permeability of the magnetic core 100 and further reduce the hysteresis loss and eddy current loss of the magnetic core 100.

[0113] The magnetic sheets 110 are arranged in a strip shape, with all magnetic sheets 110 extending in the same direction, and the extension direction of the magnetic sheets 110 is perpendicular to the stacking direction of the magnetic sheets 110. This further facilitates the winding of the magnetic sheets 110 to form a magnet 200.

[0114] Both cut surfaces 130 are obtained by cutting with a magnet. Along the extension direction of the magnetic sheet 110, the two cut surfaces 130 are located at both ends of the magnetic sheet 110, and the two cut surfaces 130 are perpendicular to the plane on which the magnetic sheet 110 is located. When cutting, two magnetic cores 100 can be obtained simultaneously by cutting one magnet 200.

[0115] As an optional implementation, the number of cut surfaces 130 is at least two. The cut surfaces 130 intersect with the tangent plane of the magnetic sheet 110. When the magnetic sheet 110 is a curved surface, the tangent plane of the magnetic sheet 110 is the plane that cuts into the magnetic sheet 110.

[0116] This can be understood as the cut surface 130 being two, three, four, etc.

[0117] The cut surface 130 is a plane formed during magnet cutting. During magnet cutting, the cut surface is chamfered to form at least two cut surfaces. The chamfering increases the uniformity of the magnetic field distribution in the air gap and reduces magnetic leakage.

[0118] When the cut surface 130 is circular, wrapping copper wire around the outside of the magnetic core can save more copper wire.

[0119] As an alternative implementation, in some embodiments, see [link to documentation]. Figure 1 , Figure 2 and Figure 7 The magnetic core 100 includes a first straight segment, an arc segment, and a second straight segment; the first straight segment, the arc segment, and the second straight segment are connected sequentially along the extension direction of the amorphous or nanocrystalline ribbon; the concave surface of the arc segment faces the first straight segment. The axis of the first straight segment and the axis of the second straight segment are parallel.

[0120] Thus, the magnetic core 100 is U-shaped overall. This allows the magnetic core 100 to be compatible with a wider range of electrical devices. It also facilitates the installation of the magnetic core 100 into electrical devices.

[0121] In addition to the U-shaped magnetic core mentioned above, magnetic core 100 can also be other irregularly shaped magnetic cores, such as E-shaped magnetic cores, I-shaped magnetic cores, square, prism-shaped or C-shaped magnetic cores, etc.

[0122] This application provides an electrical device that includes any of the above-described magnetic cores 100.

[0123] In this embodiment, the magnetic core 100 includes at least two magnetic sheets 110 and an adhesive layer 120. The at least two magnetic sheets 110 are stacked, and an adhesive layer 120 is provided between any two adjacent magnetic sheets 110. Thus, in the magnetic core 100, the direction parallel to the plane of the magnetic sheets 110 is the easy magnetization direction, and the direction perpendicular to the plane of the magnetic sheets 110 is the difficult magnetization direction. That is, the magnetic core 100 exhibits magnetic anisotropy. This results in different values ​​of permeability in different directions. The permeability is higher in the easy magnetization direction and lower in the difficult magnetization direction. Therefore, in practical applications, the permeability of the magnetic core 100 can be increased by utilizing the easy magnetization direction. When the magnetic core 100 is installed in the electrical equipment, the relevant electromagnetic performance of the electrical equipment can be improved.

[0124] The magnetic anisotropy exhibited by the aforementioned magnetic core 100 also affects the movement of domain walls and the reversal of magnetic moments. Specifically, in the easy magnetization direction, the movement of domain walls and the reversal of magnetic moments do not require overcoming a large energy barrier, thus reducing the hysteresis loss and eddy current loss of the magnetic core 100. When the magnetic core 100 is installed in the electrical equipment, it can further improve the relevant electromagnetic performance of the electrical equipment.

[0125] Because the magnetic core 100 has a cut surface 130, the flatness Fl of the cut surface 130 is ≤20μm and the roughness Rz of the cut surface 130 is ≤10μm; all magnetic sheets 110 and all adhesive layers 120 intersect with the cut surface 130. Thus, after the cut surfaces 130 of the two magnetic cores 100 are brought together, the gap width between the two cut surfaces 130 can meet the installation requirements of the magnetic core 100, thereby facilitating the installation of the magnetic core onto the electrical equipment, and thus facilitating the production of the electrical equipment.

[0126] It should be noted that the aforementioned electrical equipment may be a precision current transformer, a high-end common-mode inductor, a high-frequency power transformer or a filter, or other types of electrical equipment. This application does not limit the specific types of electrical equipment.

[0127] This application also provides a method for preparing a magnetic core, which is used to prepare any of the above-described magnetic cores 100. This method is a first method for preparing a magnetic core.

[0128] Figure 4This is a flowchart of a method for preparing a magnetic core according to an embodiment of this application. See also... Figure 3 and Figure 4 The method for manufacturing this magnetic core includes:

[0129] Step S1: Magnetic sheets are used to form a magnet; wherein the magnet has at least two layers of magnetic sheets, which are stacked; and there are filling gaps between adjacent magnetic sheets.

[0130] In this step, the magnet can be prepared by winding. Specifically, a constant tension is first applied to the magnetic sheet 110 to make it taut along the direction of the tension, thereby generating a large tension inside the magnetic sheet 110. Then, a winding device is used to wind the magnetic sheet 110 to form a magnet 200. Finally, a clamping device is used to hold the magnet 200 and fabricate it into the magnet to be processed.

[0131] In this step, the magnet can also be manufactured by stacking. Specifically, at least two layers of magnetic sheets are stacked under applied pressure, with gaps between adjacent magnetic sheets. By adjusting the shape of the magnetic sheets, magnets of various shapes can be stacked, such as U-shaped, C-shaped, E-shaped, or various irregularly shaped magnets.

[0132] Step S2: Bond the magnets together with adhesive and cure them to form a whole.

[0133] In some alternative embodiments, the magnet is first immersed in the liquid adhesive and then removed from the liquid adhesive, allowing the liquid adhesive filling the gaps to solidify.

[0134] In this step, the magnet 200 is first immersed in liquid adhesive under vacuum for a period of time, during which time the liquid adhesive will fill the gaps between adjacent magnetic sheets 110. Then, the immersed magnet 200 is removed from the liquid adhesive. Finally, the liquid adhesive is cured at a set temperature.

[0135] This process increases the mechanical strength of the magnetic core 100, which not only meets the requirements of the cutting process but also effectively reduces the attenuation of the magnetic properties of the magnetic core 100.

[0136] It should be noted that the above-mentioned adhesive can be organic resins such as epoxy resin, polyurethane, polyester, and polyimide, or inorganic adhesives such as silicate-based and phosphate-based adhesives. This application does not limit the specific adhesives used.

[0137] It should also be noted that the duration for which the magnet 200 is immersed in the liquid adhesive is related to the viscosity of the adhesive. Specifically, the higher the viscosity of the adhesive, the longer the immersion time is required; the lower the viscosity of the adhesive, the shorter the immersion time is required.

[0138] It should also be noted that the temperature required for the curing of the above-mentioned liquid adhesive must be greater than 50°C and less than 200°C.

[0139] Step S3: Cut the solidified magnet to obtain the magnetic core. The cut surface of the magnetic core intersects with the plane where the magnetic sheet is located.

[0140] In this step, the magnet 200 can be cut using laser cutting. During cutting, the cutting surface should intersect with the plane where the magnetic sheet 110 is located, thus obtaining the magnetic core 100.

[0141] It should be noted that, in addition to laser cutting, the above-mentioned cutting methods can also be wire cutting or abrasive wheel cutting, and this application does not limit the specific methods used.

[0142] It should also be noted that the magnet 200 can be cut in half along the axis of symmetry or at other locations when it is cut. This application embodiment does not limit this.

[0143] In some alternative implementations, the method for fabricating the magnetic core also includes:

[0144] Step S4: Grind the cut surface of the magnetic core.

[0145] It should be noted that the above-mentioned polishing process can be carried out using a surface grinder, or using sandpaper or a grinding wheel; this application does not limit the specific method used.

[0146] As an optional implementation, immersing the magnet in the liquid adhesive and then removing it from the liquid adhesive, and allowing the liquid adhesive filling the gaps to solidify, includes:

[0147] The magnets removed from the liquid adhesive are heated and cured to solidify the liquid adhesive filling the gaps.

[0148] During the heating and curing process, the liquid adhesive located in the filling gap can gradually solidify to form an adhesive layer 120, which in turn can form a magnet 200 with magnetic sheets 110 and adhesive layer 120 alternately arranged.

[0149] Of course, in addition to the above-mentioned impregnation method to bond two adjacent magnetic sheets 110 together to form a magnet 200, the magnetic sheets 110 can also be bonded and cured by coating, spraying or injection molding.

[0150] As an optional implementation method, the method for preparing the magnetic core further includes:

[0151] Between steps S1 and S2, a magnetic field is applied to the magnet, the direction of which is parallel to the plane on which the magnetic sheet is located; or, the magnet is heated in an environment without a magnetic field.

[0152] In this embodiment, by applying a magnetic field to the magnet 200, the magnetic anisotropy of the magnet 200 can be modulated and its magnetic properties optimized. Specifically, the magnetic field can increase the permeability of the magnet 200, making it easier for the magnetic field to conduct within the magnet 200. In the easy magnetization direction, the permeability of the magnet 200 is higher, and the magnetic field response is more sensitive, thereby increasing the permeability of the magnet 200 and consequently increasing the permeability of the magnetic core 100. Furthermore, by applying a magnetic field to the magnet 200, the hysteresis loop of the material can be smoothed, reducing coercivity and losses. Under the influence of the magnetic field, the magnetic domain structure of the material changes, forming a simpler domain structure and higher induced uniaxial anisotropy, making the domain walls easier to move, thereby reducing energy losses during the magnetization and demagnetization processes of the magnet 200.

[0153] In this embodiment, the magnet 200 is heated in a magnetic field-free environment. This improves the microstructure of the magnetic sheet 110, optimizes the magnetic properties of the magnet 200, increases the permeability of the magnet 200, reduces the coercivity of the magnet 200, and improves the high-frequency characteristics of the magnet 200. Furthermore, it allows for the full release of internal stress in the magnet 200, improving its dimensional stability and the consistency of its magnetic properties. It also enhances the toughness and weldability of the magnet 200, making it easier to process.

[0154] Based on the above analysis, the influencing factors of the magnetic permeability, hysteresis loss and eddy current loss of the magnetic core 100 are: the thickness H1 of the magnetic sheet 110, the filling coefficient K of the magnetic sheet 110, the bonding area ratio α of the magnetic core 100, whether a magnetic field is applied to the magnet 200, and whether the magnet 200 is heat-treated.

[0155] In the experiment, by changing the above-mentioned influencing factors, relevant experimental data on the permeability and loss of magnetic core 100 were obtained. The specific experimental data are shown in the table below:

[0156]

[0157] This application also provides a method for preparing a magnetic core, which is used to prepare any of the above-described magnetic cores 100. This method is a second method for preparing a magnetic core.

[0158] Figure 5 This is a flowchart illustrating another method for fabricating a magnetic core according to an embodiment of this application. See also...Figure 5 The method for manufacturing this magnetic core includes:

[0159] Step S51: Apply liquid adhesive to the surface of the magnetic sheet.

[0160] In this step, the adhesive can be the same as the adhesive used in the first method for preparing the magnetic core. The above coating method can be applied mechanically or manually, and the coating thickness should meet the thickness requirements of the adhesive layer 120.

[0161] Step S52: Winding magnetic sheets to form a magnet, or stacking multiple magnetic sheets layer by layer to form a magnet; wherein the magnet has at least two layers of magnetic sheets, the at least two layers of magnetic sheets are stacked radially along the magnet, liquid adhesive is filled between adjacent magnetic sheets, and the liquid adhesive in the filling gap is cured.

[0162] In this step, the magnet can be prepared by winding. Specifically, a constant tension is first applied to the magnetic sheet 110 to make it taut along the direction of tension, thereby generating a large internal tension in the magnetic sheet 110. Then, a winding device is used to wind the magnetic sheet 110 to form a magnet 200, at which point the magnet 200 can form a laminated structure with alternating layers of adhesive layer 120 and magnetic sheet 110. Finally, the liquid adhesive is cured under a set temperature environment.

[0163] Magnets can be manufactured by layering. Specifically, at least two magnetic sheets are stacked under applied pressure, with gaps between adjacent sheets. By adjusting the shape of the magnetic sheets, various shapes of magnets can be formed, such as U-shaped, C-shaped, E-shaped, or various irregularly shaped magnets.

[0164] Step S53: Cut the magnet with adhesive solidified in the filling gap to obtain the magnetic core; the cut surface of the magnetic core intersects with the plane where the magnetic sheet is located.

[0165] In this step, the magnet 200 can be cut using laser cutting. During cutting, the cutting surface should intersect with the plane where the magnetic sheet 110 is located, thus obtaining the magnetic core 100.

[0166] It should be noted that, in addition to laser cutting, the above-mentioned cutting methods can also be wire cutting or abrasive wheel cutting, and this application does not limit the specific methods used.

[0167] It should also be noted that the magnet 200 can be cut in half along the axis of symmetry or at other locations when it is cut. This application does not limit this.

[0168] Step S54: Grind the cut surface of the magnetic core.

[0169] It should be noted that the above-mentioned polishing process can be carried out using a surface grinder, or using sandpaper or a grinding wheel; this application does not limit the specific method used.

[0170] As an optional implementation, magnetic sheets are wound to form a magnet having at least two layers of magnetic sheets stacked radially along the magnet, with liquid adhesive filling the gaps between adjacent magnetic sheets, and curing the liquid adhesive in the gaps includes:

[0171] The wound magnet is heated and cured to solidify the liquid adhesive in the gaps.

[0172] During the heating and curing process, the liquid adhesive located in the filling gap can gradually solidify to form an adhesive layer 120, which in turn can form a magnet 200 with magnetic sheets 110 and adhesive layer 120 alternately arranged.

[0173] As an optional implementation method, the method for preparing the magnetic core further includes:

[0174] Before cutting the magnet, apply a magnetic field to the magnet, with the direction of the magnetic field parallel to the plane where the magnetic sheet is located; or heat the magnet in an environment without a magnetic field.

[0175] In this embodiment, the effect of applying a magnetic field to the magnet 200 is the same as the effect of applying a magnetic field to the magnet 200 in the preparation method of the first magnetic core, so it will not be described again here.

[0176] Furthermore, in this embodiment, the effect of heating the magnet 200 in a magnetic field-free environment is the same as the effect of heating the magnet 200 in a magnetic field-free environment in the first method of preparing the magnetic core, so it will not be described again here.

[0177] The magnetic core 100, manufactured by the two methods described above, comprises at least two magnetic sheets 110 and an adhesive layer 120. The at least two magnetic sheets 110 are stacked. An adhesive layer 120 is disposed between any two adjacent magnetic sheets 110. The magnetic core 100 has a cut surface 130, the flatness Fl of the cut surface 130 being ≤20μm and the roughness Rz of the cut surface 130 being ≤10μm. All magnetic sheets 110 and all adhesive layers 120 intersect with the cut surface 130.

[0178] Since the magnetic core 100 includes at least two magnetic sheets 110 and an adhesive layer 120, with the at least two magnetic sheets 110 stacked together and an adhesive layer 120 between any two adjacent magnetic sheets 110, the direction parallel to the plane of the magnetic sheets 110 is the easy magnetization direction, and the direction perpendicular to the plane of the magnetic sheets 110 is the difficult magnetization direction. This means the magnetic core 100 exhibits magnetic anisotropy. Consequently, the permeability will have different values ​​in different directions. The permeability is higher in the easy magnetization direction and lower in the difficult magnetization direction. Therefore, in practical applications, the permeability of the magnetic core 100 can be increased by utilizing the easy magnetization direction.

[0179] The magnetic anisotropy exhibited by the magnetic core 100 also affects the movement of domain walls and the reversal of magnetic moments. Specifically, in the easy magnetization direction, the movement of domain walls and the reversal of magnetic moments do not require overcoming a large energy barrier, thus reducing the hysteresis loss and eddy current loss of the magnetic core 100.

[0180] Because the magnetic core 100 has a cut surface 130, the flatness Fl of the cut surface 130 is ≤20μm, and the roughness Rz of the cut surface 130 is ≤10μm; all magnetic sheets 110 and all adhesive layers 120 intersect with the cut surface 130. Thus, after the cut surfaces 130 of two magnetic cores 100 are brought together, the gap width between the two cut surfaces 130 can meet the installation requirements of the magnetic core 100. This achieves the standard for the morphological appearance of the cut surface 130 of the magnetic core 100.

[0181] As an alternative implementation, the process of immersing the adhesive in step 32 can be replaced by spraying or injection molding.

[0182] Figure 6 This is a flowchart of another method for preparing a magnetic core provided in the embodiments of this application, referred to... Figure 6 The method for manufacturing this magnetic core includes:

[0183] Step S61: Stacking magnetic sheets to form a magnet, or winding magnetic sheets to form a magnet; wherein the magnet has at least two layers of magnetic sheets, the at least two layers of magnetic sheets being stacked; and there are filling gaps between adjacent magnetic sheets.

[0184] The method of forming the magnet in this step can refer to the above embodiment, and will not be repeated here.

[0185] Step S62: Apply a magnetic field to the magnet; or, heat-treat the magnet in a non-magnetic environment.

[0186] The application of the magnetic field and the heat treatment methods can be referred to in the above embodiments, and will not be repeated here.

[0187] Step S63: Spray liquid adhesive onto the magnet to fill the gaps with liquid adhesive and cure it to bond it into a whole.

[0188] The magnet is manufactured using a winding or lamination process, with at least two layers of magnetic sheets stacked together, and gaps between adjacent magnetic sheets. An adhesive is sprayed onto the magnet surface and cured into a film. The adhesive includes, but is not limited to, organic adhesives such as epoxy resin and polyurethane, or inorganic adhesives such as aluminum dihydrogen phosphate.

[0189] Step S64: Cut the magnet with adhesive sprayed and cured on the surface to obtain the magnetic core. The cut surface intersects with the cutting plane of the magnetic sheet.

[0190] Step S65: Grind the cut surface of the magnetic core.

[0191] The magnetic core prepared in this way also has the same advantages as the magnetic core in the above embodiments, which will not be repeated here.

[0192] Figure 7 This is a flowchart illustrating another method for preparing a magnetic core provided in this application embodiment, with reference to... Figure 7 The method for manufacturing this magnetic core includes:

[0193] Step S71: Stacking magnetic sheets to form a magnet, or winding magnetic sheets to form a magnet; wherein the magnet has at least two layers of magnetic sheets, the at least two layers of magnetic sheets being stacked; and there are filling gaps between adjacent magnetic sheets.

[0194] The method of forming the magnet in this step can refer to the above embodiment, and will not be repeated here.

[0195] Step S72: Apply a magnetic field to the magnet; or, heat-treat the magnet in a non-magnetic environment.

[0196] The application of the magnetic field and the heat treatment methods can be referred to in the above embodiments, and will not be repeated here.

[0197] Step S73: Use injection molding equipment to inject polymer plastic into the gaps and cure and bond it into a whole.

[0198] The magnet is manufactured using a winding or lamination process, with at least two layers of magnetic sheets stacked together, and gaps between adjacent magnetic sheets. An injection molding process is used to encapsulate the magnet with a plastic material. This plastic material includes, but is not limited to, thermoplastic resins such as PET and PP, as well as various filler components such as glass fiber and carbon fiber added to the plastic material.

[0199] Step S74: Cut the injection-molded magnet to obtain a magnetic core; wherein the cut surface of the magnetic core intersects with the cutting plane of the magnetic sheet.

[0200] Step S74: Grind the cut surface of the magnetic core.

[0201] The magnetic core prepared in this way also has the same advantages as the magnetic core in the above embodiments, which will not be repeated here.

[0202] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0203] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0204] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something,” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “above something” or “on top of something,” but also “on something” or “on top of something” without an intermediate feature or layer therebetween, i.e., directly on something.

[0205] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations rotated 90° or be in other orientations, and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0206] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A magnetic core, characterized in that, include: At least two magnetic sheets are stacked together. An adhesive layer is provided between any two adjacent magnetic sheets; the magnetic core has a cut surface, the flatness of the cut surface Fl≤20μm, and the roughness of the cut surface Rz≤10μm; all the magnetic sheets and all the adhesive layers intersect with the cut surface.

2. The magnetic core according to claim 1, characterized in that, The flatness of the cut surface Fl ≤ 2 μm, and the roughness of the cut surface Rz ≤ 1 μm; further, the flatness of the cut surface Fl ≤ 0.5 μm, and the roughness of the cut surface Rz ≤ 0.1 μm.

3. The magnetic core according to claim 1, characterized in that, The thickness H1 of the magnetic sheet is in the range of 5μm≤H1≤30μm.

4. The magnetic core according to claim 1, characterized in that, The filling factor K of the magnetic core composed of the magnetic sheet has the following values: K≥0.6; further, K≥0.7; further still, K≥0.8; the ratio of the actual mass of the magnetic core to the theoretical mass of the magnetic core is the filling factor K.

5. The magnetic core according to claim 1, characterized in that, The magnetic sheet is made of amorphous alloy strip, and the thickness H1 of the magnetic sheet is in the range of 20μm≤H1≤30μm, preferably 23μm≤H1≤28μm; the fill factor K is in the range of 0.8≤K≤0.9; the fill factor K is the ratio of the actual mass of the magnetic core to the theoretical mass of the magnetic core.

6. The magnetic core according to claim 1, characterized in that, The magnetic sheet is made of nanocrystalline alloy strip, and the thickness H1 of the magnetic sheet is in the range of 10μm≤H1≤18μm, preferably 12μm≤H1≤16μm; the filling coefficient K is in the range of 0.8≤K≤0.9; the ratio of the actual mass of the magnetic core to the theoretical mass of the magnetic core is the filling coefficient K.

7. The magnetic core according to any one of claims 1-6, characterized in that, On the cut surface, the cross sections of some of the magnetic sheets are interconnected to form an adhesive surface; On the cut surface, the ratio of the sum of the areas of all the adhesive surfaces to the area of ​​the cut surface is the adhesive area ratio α; the range of the adhesive area ratio α is: α≤0.

95.

8. The magnetic core according to claim 7, characterized in that, The value range of the adhesion area ratio α is: α≤0.5, and more preferably α≤0.

1.

9. The magnetic core according to any one of claims 1-6, characterized in that, The number of cut surfaces is at least two; the cut surfaces intersect with the cutting plane where the magnetic sheet is located.

10. The magnetic core according to any one of claims 1-6, characterized in that, The magnetic core includes a first straight segment, an arc segment, and a second straight segment; along the extending direction of the magnetic sheet, the first straight segment, the arc segment, and the second straight segment are connected in sequence; the concave surface of the arc segment faces the first straight segment; The axis of the first straight line segment is parallel to the axis of the second straight line segment.

11. The magnetic core according to any one of claims 1-6, characterized in that, The magnetic core is an irregularly shaped magnetic core; or, the magnetic core is a C-shaped, square, prism-shaped, E-shaped, U-shaped, or I-shaped magnetic core.

12. An electrical device, characterized in that, Includes the magnetic core as described in any one of claims 1-11.

13. A method for preparing a magnetic core, characterized in that, A method for preparing a magnetic core according to any one of claims 1-11, comprising: Step S1: Magnetic sheets are used to form a magnet, the magnet having at least two layers of the magnetic sheets, the at least two layers of the magnetic sheets being stacked; there are filling gaps between adjacent magnetic sheets; Step S2: The magnets are bonded and cured with adhesive to form a whole; Step S3: Cut the solidified magnet to obtain the magnetic core; the cut surface of the magnetic sheet intersects with the cutting plane on which the magnetic sheet is located.

14. The preparation method according to claim 13, characterized in that, It also includes step S4, which involves polishing the cut surface of the magnetic core.

15. The preparation method according to claim 13, characterized in that, In step S2, the magnet is bonded and cured by impregnation, coating, spraying or injection molding.

16. The preparation method according to claim 13, characterized in that, The magnet is manufactured by winding or stacking.

17. The preparation method according to claim 13, characterized in that, The method for preparing the magnetic core further includes: applying a magnetic field to the magnet between step S1 and step S2; Alternatively, between steps S1 and S2, the magnet may be heat-treated in a non-magnetic environment.

18. A method for preparing a magnetic core, characterized in that, A method for preparing a magnetic core according to any one of claims 1-11, comprising: A liquid adhesive is applied to the surface of the magnetic sheet; The magnetic sheet is wound to form a magnet, or multiple magnetic sheets are stacked layer by layer to form a magnet; wherein the magnet has at least two layers of magnetic sheets, the at least two layers of magnetic sheets are stacked, and the space between adjacent magnetic sheets is filled with liquid adhesive, and the adhesive is cured. The magnet, in which the adhesive is cured in the gap, is cut to obtain the magnetic core; wherein the cut surface of the magnetic core intersects with the plane on which the magnetic sheet is located; The cut surface of the magnetic core is polished.

19. The preparation method according to claim 18, characterized in that, Before cutting the magnet, a magnetic field is applied to the magnet; or, the magnet is heat-treated in a non-magnetic environment.

20. A method for preparing a magnetic core, characterized in that, A method for preparing a magnetic core according to any one of claims 1-11, comprising: Magnetic sheets are stacked to form a magnet, or the magnetic sheets are wound to form a magnet; wherein the magnet has at least two layers of the magnetic sheets, and the at least two layers of the magnetic sheets are stacked; there are filling gaps between adjacent magnetic sheets; Apply a magnetic field to the magnet; or, heat-treat the magnet in a non-magnetic environment. A liquid adhesive is sprayed onto the magnet to fill the gaps with the liquid adhesive, and then cured and bonded into a whole. The magnet, on which the adhesive has been sprayed and cured, is cut to obtain the magnetic core, with the cut surface intersecting the cutting plane where the magnetic sheet is located; The cut surface of the magnetic core is polished.

21. The preparation method according to claim 20, characterized in that, The step of spraying the liquid adhesive onto the surface of the magnet and curing it to bond it into a whole includes: subjecting the magnet to a heat curing treatment to cure the liquid adhesive.

22. A method for preparing a magnetic core, characterized in that, A method for preparing a magnetic core according to any one of claims 1-11, comprising: Magnetic sheets are stacked to form a magnet, or the magnetic sheets are wound to form a magnet; wherein the magnet has at least two layers of the magnetic sheets, and the at least two layers of the magnetic sheets are stacked; there are filling gaps between adjacent magnetic sheets; Apply a magnetic field to the magnet; or, heat-treat the magnet in a non-magnetic environment. High molecular weight plastic is injected into the filling gap using injection molding equipment and then cured and bonded into a whole; The injection-molded magnet is cut to obtain the magnetic core; wherein the cut surface of the magnetic core intersects with the cutting plane of the magnetic sheet; The cut surface of the magnetic core is polished.

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