Magnetic material

Abstract

To provide a magnetic material that can reduce thermal stress in the core. [Solution] A magnetic member comprising: a core having an inner leg portion and at least two outer legs; at least one spacer; and at least two coils, wherein the at least two coils and the at least one spacer are stacked on top of each other and sleeve-fixed directly to the inner leg portion, and each of the at least two coils is formed by winding a wire covered with at least three staggered layers of insulating tape.

Description

【Technical Field】 【0001】 The present invention relates to a magnetic member, and more particularly to a magnetic member capable of reducing the thermal stress of a core. 【Background Art】 【0002】 In response to the demand for rapid charging of electric vehicles, the operating power is increasing, and the heat generated from electronic components is also gradually increasing. The magnetic members of in-vehicle chargers (OBCs) such as transformers generate heat due to losses during operation, and the non-uniform heat causes additional thermal stress on the transformer core. Thermal stress increases the loss of the transformer core, and the heat does not converge under continuous cycles, resulting in excessively high temperatures and losses. As a result, in extreme cases, irreversible damage occurs to the core. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Taiwan Patent Application Publication No. 201917745A 【Patent Document 2】 Taiwan Patent Application Publication No. 202303640A 【Patent Document 3】 Taiwan Patent Application Publication No. 200509154A 【Patent Document 4】 U.S. Patent Application Publication No. 2021 / 0407728A1 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 The present invention has been made to solve the above problems, and an object thereof is to provide a magnetic member capable of reducing the thermal stress of a core. 【Means for Solving the Problems】 【0005】 In one embodiment of the present invention, the magnetic member comprises a core, at least one coil, and a thermally conductive filler. The core has an inner leg portion, at least two outer legs, and at least one non-jointed region. At least one coil is wound around the inner leg portion or at least two outer legs. The thermally conductive filler covers a portion of the core. At least a portion of the at least one non-jointed region is not covered by the thermally conductive filler. 【0006】 In another embodiment of the present invention, the magnetic member comprises a core, at least one coil, and a thermally conductive filler. The core has an inner leg portion, at least two outer legs, and at least one non-jointed region. The at least one non-jointed region is located on at least two outer legs. The at least one coil is wound around the inner leg portion or at least two outer legs. The thermally conductive filler covers a portion of the core and at least one non-jointed region located on at least two outer legs. 【0007】 In another embodiment of the invention, the magnetic member comprises a core, a bobbin, at least one coil, and a thermally conductive filler. The core has an inner leg portion, at least two outer legs, and a plurality of non-jointed regions. The plurality of non-jointed regions are located on the inner leg portion and at least two outer legs. The bobbin is sleeved to the inner leg portion. The upper surface of the bobbin is joined to the inner plate surface of the core. At least one coil is located on the bobbin. The thermally conductive filler covers a portion of the core but does not cover the plurality of non-jointed regions. 【0008】 In another embodiment of the present invention, the magnetic member comprises a core, at least one spacer, and at least two coils. The core has an inner leg and at least two outer legs. The at least two coils and at least one spacer are stacked on top of each other and sleeve-fixed directly to the inner leg. Each of the at least two coils is formed by winding a wire covered with at least three misaligned layers of insulating paper tape. 【0009】 As described above, in one embodiment, at least one non-jointed region may be located on the inner leg or at least two outer legs, and at least a portion of the at least one non-jointed region may not be covered with a thermally conductive filler. This allows the inner leg or at least two outer legs having the non-jointed region to deform freely even if the temperature difference (or maximum temperature) of the core increases, thereby reducing the thermal stress of the core and suppressing an increase in core loss. Furthermore, in another embodiment, at least one non-jointed region may be located on at least two outer legs, and the thermally conductive filler may cover at least one non-jointed region. Similarly, the at least two outer legs having the non-jointed region can deform freely even if the temperature difference (or maximum temperature) of the core increases, thereby reducing the thermal stress of the core and suppressing an increase in core loss. In another embodiment, the coils and spacers may be stacked on top of each other and sleeve-fixed directly to the inner leg of the core, in which case it is not necessary to wind the coils on a bobbin in order to improve the insulation and heat dissipation effects between the primary and secondary coils and between the coils and the core. Therefore, the magnetic members are no longer limited by the size and spacing of the bobbins, the spacers may be in close contact with the coils, the structure of the coil cover may extend between the two coils, the distance and spacing between the spacers and coils may be fixed to a minimum, and the size of the magnetic members may be minimized. 【0010】 Those skilled in the art will see that these and other objects of the present invention become apparent upon reading the following detailed description of preferred embodiments shown in the various drawings. [Brief explanation of the drawing] 【0011】 [Figure 1] This is a cross-sectional view showing a magnetic member according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Figure 3]It is an exploded view showing the spacer, coil cover, and two coils shown in FIG. 2. [Figure 4] It is a schematic diagram showing four spacers of different shapes. [Figure 5] It is a schematic diagram showing a wire covered by three offset layers of insulating tape. [Figure 6] It is a perspective view showing a magnetic member according to another embodiment of the present invention. [Figure 7] It is a cross-sectional view showing the magnetic member shown in FIG. 6. [Figure 8] It is another cross-sectional view showing the magnetic member shown in FIG. 6. [Figure 9] It is a perspective view showing the bobbin shown in FIG. 7. [Figure 10] It is a top view showing the bobbin shown in FIG. 9. [Figure 11] It is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Figure 12] It is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Figure 13] It is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Figure 14] It is a perspective view showing a magnetic member according to another embodiment of the present invention. [Figure 15] It is a perspective view showing a magnetic member according to another embodiment of the present invention. 【Mode for Carrying Out the Invention】 【0012】 Referring to FIG. 1, FIG. 1 is a cross-sectional view showing a magnetic member 1 according to an embodiment of the present invention. 【0013】 The magnetic member 1 of the present invention may be a reactor, a transformer, an inductor, or other magnetic members. As shown in FIG. 1, the magnetic member 1 includes a core 10, at least one coil 12, and a thermal conductive filler 14. The core 10 has an inner leg 100, at least two outer legs 102, at least one non-junction region 104, and at least one junction region 106. In this embodiment, the core 10 may include a first core member 10a and a second core member 10b. The inner leg 100 is a central pillar extending from the center of the first core member 10a, and the two outer legs 102 may be side pillars extending from the periphery of the first core member 10a. Therefore, in this embodiment, the first core member 10a may be an E-core, a PQ-core, a T-core, or an F-core, and the second core member 10b may be an I-core, a UU-core, a U-core, a U-I-core, an E-I-core, or an F-core. However, the types of the first core member 10a and the second core member 10b may be determined according to actual applications. Therefore, the present invention is not limited to the shown embodiments. 【0014】 At least one coil 12 may be wound around the inner leg 100 or at least two outer legs 102. In this embodiment, the coil 12 is wound around the inner leg 100, but the present invention is not limited thereto. In another embodiment, the coil 12 may be wound around at least two outer legs 102. In this embodiment, the second core member 10b is disposed on the first core member 10a, and the inner leg 100 is joined to the second core member 10b to form a junction region 106. Further, the second core member 10b is not joined to the two outer legs 102, and two non-junction regions 104 are disposed between the two outer legs 102 and the second core member 10b. The type of the coil 12 may be a circular wire, a rectangular wire, or a multi-stranded wire. 【0015】 In this embodiment, the core 10 is placed inside the casing 16, and the thermal conductive filler 14 is filled into the casing 16, so that the thermal conductive filler 14 covers a portion of the core 10. In this case, at least a portion of at least one non-jointed region 104 is not covered by the thermal conductive filler 14. As shown in Figure 1, the two non-jointed regions 104 and the jointed region 106 are not covered by the thermal conductive filler 14. As a result, even if the temperature difference (or maximum temperature) of the core 10 rises, the two outer legs 102 having the two non-jointed regions 104 can deform freely, reducing the thermal stress of the core 10 and suppressing the increase in core 10 losses. For example, in the case of an inductor or transformer with a power of 6.6 kW, the maximum thermal stress may be reduced from 68 MPa to 27 MPa, and the maximum temperature of the core 10 may be reduced from 154°C to 96°C. It should be noted that the inner plate surface 110 of the core 10 does not need to be covered by the thermal conductive filler 14. 【0016】 In this embodiment, the thermal conductivity of the thermally conductive filler 14 is greater than 0.3 W / mk, and the material of the thermally conductive filler 14 may include epoxy, silicone, polyurethane (PU), phenolic resins, thermoplastic polyethylene terephthalate (PET), polyamide (PA), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), and the like. 【0017】 Referring to Figures 2 to 5, Figure 2 is a cross-sectional view showing a magnetic member 1 according to another embodiment of the present invention; Figure 3 is an exploded view showing the spacer 18, coil cover 19 and two coils 12 shown in Figure 2; Figure 4 is a schematic diagram showing four spacers 18 of different shapes; and Figure 5 is a schematic diagram showing a wire 122 covered by three staggered layers of insulating tape 120. In some embodiments, the material of the spacer 18 is electrically insulating and magnetically permeable, or electrically insulating and thermally conductive. For example, the spacer 18 may be formed by injection molding after mixing magnetic powder and plastic, or it may be formed from a magnetic material (e.g., ferrite), or it may be formed from a material (e.g., ceramic) that has high thermal conductivity and electrical insulation properties. In this embodiment, at least one coil 12 may have a primary coil 12a and a secondary coil 12b, and its cross-section may be circular, elliptical or rectangular. A rectangular shape may effectively improve volume utilization. As shown in Figure 4, the spacer 18 may have a ring-shaped (e.g., circular, elliptical, semicircular, or semi-elliptical) structure positioned between the primary coil 12a and the secondary coil 12b. This may increase the leakage inductance (Lk) and power density. The magnetic member 1 may also have a coil cover 19, which is sleeve-fixed directly to the inner legs 100 of the coil 10 and stacked above the spacer 18 and the two coils 12. The coil cover 19 is configured to lead the ends of the coils 12 out of the core 10 via guide grooves 19a. In this embodiment, the coil cover 19 is electrically insulated. In this embodiment, the spacer 18 further has a guide groove 18b corresponding to the guide groove 19a of the coil cover 19. When the spacer 18, coil cover 19, and two coils 12 are stacked on top of each other and directly sleeve-fixed to the inner leg portion 100 of the core 10, the ends of the coils 12 are led out from the core 10 through the guide groove 19a of the coil cover 19 and the guide groove 18b of the spacer 18. 【0018】 As shown in Figures 2 and 3, the magnetic member 1 may have a core 10, at least one spacer 18, and at least two coils 12, where the at least two coils 12 and at least one spacer 18 are stacked on top of each other and directly sleeve-fixed onto the inner leg portion 100. In this embodiment, the magnetic member 1 is constructed by stacking the spacer 18, the coil cover 19, and the two coils 12 on top of each other. The coils 12 do not need to be wound on a bobbin. After the coils 12 are wound onto an air coil, the coils 12 and the spacer 18 are stacked on top of each other and directly sleeve-fixed onto the inner leg portion 100 of the core 10. In this embodiment, the winding structure of the coils 12 is derived from the outside of the upper and lower layers (outside-outside winding), which has better flatness than another winding structure derived from the inside (inside-outside winding). Therefore, the magnetic member 1 does not need to be limited by the size and spacing of the bobbins, the spacer 18 may be in close contact with the coil 12, or the structure of the coil cover 19 may extend between the two coils 12, fixing the distance and gap between the spacer 18 and the coil 12 to the minimum possible extent, thereby minimizing the size of the magnetic member 1. Furthermore, since the space and size of the magnetic member 1 can be minimized, the heat dissipation path is shortened, and the magnetic member 1 does not need to have a structure covering the inner leg portion 100 (e.g., a coil cover and bobbin with covering walls), resulting in good heat dissipation. In this embodiment, the spacer 18 has an air gap 18a. When the spacer 18 and the two coils 12 are stacked, the gap 18a between the two opposing stacked surfaces of the two coils 12 is filled with a thermally conductive filler 14, which fills the opposing surfaces between the inner leg portion 100 and the two coils 12. The thermally conductive filler 14 also covers the outer surfaces of the two coils 12 and the spacer 18, increasing the heat dissipation surface of the two coils 12 and potentially providing a good heat dissipation effect. In embodiments where the thermally conductive filler 14 is absent, the spacer and coils are not sleeve-fixed on the bobbin, allowing airflow to easily enter the spacer 18, coil cover 19, and the two coils 12, potentially providing a good heat dissipation effect.In some embodiments, to maintain the same insulation between the two coils 12 and between the two coils 12 and the bobbinless core 10, each of the two coils 12 may be formed by winding a wire 122 covered with at least three staggered layers of insulating tape 120 (as shown in Figure 5). A single insulating tape 120 may be staggered and laminated from a first layer to at least a second or third layer, with a staggered overlap ratio W2 / W1 greater than 67%, where W1 represents the width of the single insulating tape 120 and W2 represents the overlap width. The insulating tape 120 may be made of polyimide film. Preferably, a single wire 122 or multiple wires 122 are enameled wires covered with an insulating layer. 【0019】 Referring to Figures 6 to 10, Figure 6 is a perspective view showing a magnetic member 1' according to another embodiment of the present invention, Figure 7 is a cross-sectional view showing the magnetic member 1' shown in Figure 6, Figure 8 is another cross-sectional view showing the magnetic member 1' shown in Figure 6, Figure 9 is a perspective view showing the bobbin 20 shown in Figure 7, and Figure 10 is a top view showing the bobbin 20 shown in Figure 9. 【0020】 The main difference between magnetic member 1' and the aforementioned magnetic member 1 is that, as shown in Figures 6 to 9, magnetic member 1' further has a bobbin 20 and the inner leg portion 100 further has a floating portion 1000. In this embodiment, the ratio T of the floating portion 1000 to the inner leg portion 100 may be 50%, or 2% to 95%. To further explain, the inner leg portion 100 has a length X1, and the floating portion 1000 has a length X2, so the ratio T of the floating portion 1000 to the inner leg portion 100 is X2 / X1. The bobbin 20 is sleeve-fixed to the inner leg portion 100, and at least one coil 12 is placed on the bobbin 20. Thus, the coil 12 is still wound around the inner leg portion 100. In this embodiment, the inside of the bobbin 20 has a protruding platform 200, and the floating portion 1000 of the inner leg portion 100 is supported by this protruding platform 200, and the floating portion 1000 is positioned between the first core member 10a and the second core member 10b. In this embodiment, the protruding platform 200 may extend from the outside to the inside of the inner leg portion 100 and support the floating portion 1000. 【0021】 In this embodiment, the first core member 10a and the second core member 10b are joined to each other by two outer legs 102, forming two joint regions 106. The second core member 10b is not joined to the floating portion 1000, which is supported by a protruding platform 200, and two non-joint regions 104a and 104b are located on opposite sides of the floating portion 1000. After the thermal conductive filler 14 is filled into the casing 16, one of the two non-joint regions 104a and 104b is not (completely) covered by the thermal conductive filler 14. As shown in Figure 7, the non-joint region 104a below the floating portion 1000 and the two joint regions 106 are covered by the thermal conductive filler 14, while the non-joint region 104b above the floating portion 1000 is not covered by the thermal conductive filler 14. As a result, the inner leg portion 100 having the non-jointed region 104b can deform freely even as the temperature difference (or maximum temperature) of the core 10 increases, reducing the thermal stress on the core 10 and suppressing the increase in core 10 losses. 【0022】 In this embodiment, the height H1 of the thermal conductive filler 14 is equal to or less than the height H2 of the bobbin 20, and the thermal conductive filler 14 does not come into contact with the bottom surface of the second core member 10b. Therefore, the thermal expansion stress of the thermal conductive filler 14 is greatly suppressed, and the second core member 10b and the inner leg portion 100 do not interact due to the high thermal stress caused by the thermal conductive filler 14, thereby reducing the temperature difference (or maximum temperature) of the core 10. Consequently, the thermal stress of the core 10 can be reduced, and the increase in core 10 losses is suppressed. 【0023】 As shown in Figures 7 and 9, at least one hole 202 is formed in the bobbin 20, allowing the thermal conductive filler 14 to come into contact with the inside of at least one coil 12, increasing the contact area between the thermal conductive filler 14 and the inner leg portion 100, thereby increasing the heat dissipation path, effectively reducing the temperature difference (or maximum temperature), and reducing additional heat loss. In this embodiment, one of the at least one hole 202 extends from the upper plate 204 to the lower plate 206 of the bobbin 20, and one boundary of the at least one hole 202 may overlap with the upper plate 204 and the lower plate 206 of the bobbin 20. As shown in Figure 9, the at least one hole 202 has two holes 202a and two holes 202b. The two holes 202b may extend from the upper plate 204 to the lower plate 206 of the bobbin 20, and the boundary 202c of each hole 202b may overlap on the upper plate 204 and the lower plate 206, as shown in Figures 9 and 10. This allows the thermally conductive filler 14 to flow more easily into the bobbin 20, and more heat may be conducted from the coil 12. In addition, the cost may be reduced because the number of molds used to manufacture (injection mold) the bobbin 20 is reduced. 【0024】 For example, when the magnetic member 1' is an inductor or transformer having a power of 5.5 KW and the ratio T of the floating portion 1000 to the inner leg portion 100 is 30%, the maximum thermal stress may be reduced from 52 MPa to 28.6 MPa, and the maximum temperature of the core 10 may be reduced from 110 °C to 87.106 °C. Even when the temperature of the floating portion 1000 is 128.45 °C, the floating portion 1000 is a simple columnar body and cracks are unlikely to occur. Considering further the winding arrangement of the coil having a large cross-sectional area, the ratio of the floating portion 1000 to the inner leg portion 100 and the winding arrangement of the coil having a large diameter are as follows. At least one coil 12 may have a primary coil 12a and a secondary coil 12b, and it should be noted that the arrangement of the secondary coil 12b corresponds to the floating portion 1000 and the arrangement of the primary coil 12a corresponds to the inner leg portion 100 of the first core 10a. The primary coil 12a has a cross-sectional area D1, and the secondary coil 12b has a cross-sectional area D2. When the cross-sectional area D1 of the primary coil 12a is larger than the cross-sectional area D2 of the secondary coil 12b, the operating temperature of the primary coil 12a is higher than the operating temperature of the secondary coil 12b, and the ratio T of the floating portion 1000 to the inner leg portion 100 is 50% < T ≦ 95%. When the cross-sectional area D1 of the primary coil 12a is smaller than the cross-sectional area D2 of the secondary coil 12b, the operating temperature of the secondary coil 12b is higher than the operating temperature of the primary coil 12a, and the ratio T of the floating portion 1000 to the inner leg portion 100 may be 2% ≦ T < 50%. 【0025】 As shown in Figures 6 and 7, the magnetic member 1' may further have a heat dissipation member 22 disposed on the core 10. The heat dissipation member 22 contacts the upper surface S1 and the side surface S2 of the core 10. In this embodiment, the magnetic member 1' may have two heat dissipation members 22 disposed on opposing sides of the core 10, although this is not limited to the magnetic member 1'. In this embodiment, the heat dissipation member 22 may be L-shaped, and the length L of the portion of the heat dissipation member 22 that contacts the side surface S2 of the core 10 may be less than the height H3 of the core 10. This allows the heat dissipation member 22 to remain in gapless contact with the upper surface S1 of the core 10 even if there are tolerance variations in the height of the core 10, thereby improving heat dissipation. Also, because there are two heat dissipation members 22 attached to the upper surface S1 and the side surface S2, the heat dissipation member 22 can be manufactured by a low-cost process with a large tolerance. The L-shaped heat dissipation member 22 is not limited to a specific application and can be applied to other embodiments. 【0026】 In this embodiment, the thermally conductive filler 14 covers a portion of the heat dissipation member 22, and the heat dissipation member 22 may transfer heat to the bottom. Furthermore, the heat dissipation member 22 may be bonded to the core 10 with an adhesive having a small Shore D or Shore A hardness of less than 80, thereby reducing the temperature difference (or maximum temperature) of the core 10 and reducing thermal stress. For example, if Shore D > 80, the corresponding maximum temperature of the core 10 can be 59.3°C, and if Shore D < 80, the corresponding maximum temperature of the core 10 can be reduced to 50.6°C. 【0027】 Referring to Figure 11, Figure 11 is a cross-sectional view of a magnetic member 1'' according to another embodiment of the present invention. 【0028】 The main difference between magnetic member 1'' and the aforementioned magnetic member 1 is that, in addition to the first core member 10a and the second core member 10b, magnetic member 1'' further has a third core member 10c. As shown in Figure 11, the first core member 10a and the second core member 10b are arranged side by side and joined to the third core member 10c by two outer legs 102, forming two joining regions 106. Furthermore, the two adjacent side walls 108a and 108b of the first core member 10a and the second core member 10b are not joined to each other, and a non-joining region 104a is located between the two adjacent side walls 108a and 108b of the first core member 10a and the second core member 10b. In this embodiment, the two adjacent side walls 108a and 108b form part of the inner leg 100. The inner leg portion 100 of the third core member 10c and the inner leg portions 100 of the first core member 10a and the second core member 10b are positioned relative to each other but are not joined, forming another non-joined region 104b. The inner leg portion 100 of the third core member 10c is formed integrally without gaps. The two adjacent side walls 108a and 108b of the first core member 10a and the second core member 10b face each other at the inner leg portion 100. 【0029】 After filling the casing 16 with thermally conductive filler 14, at least a portion of the non-jointed region 104a is not covered by the thermally conductive filler 14. As shown in Figure 11, the lower part of the non-jointed region 108a between the two adjacent side walls 104a and 108b, and the two jointed regions 106 are covered by the thermally conductive filler 14, while the upper part of the non-jointed region 104a is not covered by the thermally conductive filler 14. In addition, the non-jointed region 104b above the inner leg portion 100 of the third core member 10c is covered by the thermally conductive filler 14. As a result, the inner leg portion 100 having the upper part of the non-jointed region 104a can deform freely even if the temperature difference (or maximum temperature) of the core 10 increases, which may reduce the thermal stress of the core 10 and suppress the increase in core 10 loss. For example, if the magnetic member 1'' is an inductor or transformer with a power of 3.7 kW, the maximum thermal stress may be reduced from 48 MPa to 16 MPa, and the maximum temperature of the core 10 may be reduced from 150°C to 120°C. 【0030】 Referring to Figure 12, Figure 12 is a cross-sectional view showing a magnetic member 1''' according to another embodiment of the present invention. 【0031】 The main difference between magnetic member 1''' and the aforementioned magnetic member 1 is that, as shown in Figure 12, the thermal conductive filler 14 covers at least one non-jointed region 104, the at least one non-jointed region 104 is located on at least two outer legs 102, and the at least one jointed region 106 is located on the inner leg 100. In this embodiment, the first core member 10a and the second core member 10b are two E cores, PQ cores, T cores, UU cores, U cores, UI cores, EI cores, I cores, or F cores, the two non-jointed regions 104 are located on two outer legs 102, and the one jointed region 106 is located on the inner leg 100. In other words, the two outer legs 102 of the core 10 are not joined, and the inner leg 100 of the core 10 is joined. After the thermal conductive filler 14 is filled into the casing 16, the thermal conductive filler 14 covers a portion of the core 10, two non-jointed regions 104 located on the two outer legs 102, and a jointed region 106 located on the inner leg 100. This allows the two outer legs 102 with the non-jointed regions 104 to deform freely even if the temperature difference (or maximum temperature) of the core 10 increases, thereby reducing the thermal stress of the core 10 and suppressing the increase in losses of the core 10. For example, if the magnetic member 1''' is an inductor or transformer with a power of 6.6 kW, the maximum thermal stress can be reduced from 68 MPa to 32.4 MPa, and the maximum temperature of the core 10 can be reduced from 154°C to 115.2°C. 【0032】 Referring to Figure 13, Figure 13 is a cross-sectional view showing a magnetic member 1'''' according to another embodiment of the present invention. 【0033】 The main difference between magnetic member 1'''' and the aforementioned magnetic member 1 is that, as shown in Figure 13, in addition to the core 10, at least one coil 12, and thermal conductive filler 14, magnetic member 1'''' further has a bobbin 20''. The core 10 has an inner leg portion 100, at least two outer leg portions 102, and a plurality of non-jointed regions 104. The plurality of non-jointed regions 104 are located on the inner leg portion 100 and at least two outer leg portions 102. The bobbin 20' is sleeve-fixed to the inner leg portion 100. The upper surface 208 of the bobbin 20' may be bonded to the inner plate surface 110 of the core 10 by adhesive. At least one coil 12 is placed on the bobbin 20'. After the thermal conductive filler 14 is filled into the casing 16, the thermal conductive filler 14 covers part of the core 10 but not the plurality of non-jointed regions 104. As a result, even if the temperature difference (or maximum temperature) of the core 10 increases, the inner leg portion 100 and at least two outer leg portions 102, which have multiple non-bonded regions 104, can be freely deformed, reducing thermal stress on the core 10 and suppressing an increase in core loss. In another embodiment, the lower surface 210 of the bobbin 20' is further bonded to another inner plate surface 112 of the core 10 by adhesive, so that the two inner plate surfaces 110, 112 face each other. 【0034】 Referring to Figure 14, Figure 14 is a perspective view showing a magnetic member 3 according to another embodiment of the present invention. 【0035】 As shown in Figure 14, the core 30 of the magnetic member 3 has a plate portion 300, and a V-shaped recess 302 is formed at the end of the plate portion 300. In this embodiment, the end of the plate portion 300 having the V-shaped recess 302 is a continuous end that does not contain discontinuous geometric structures, and stress concentration is avoided. In this embodiment, the position of the joint between the two ends of the V-shaped recess 302 may correspond to the inner leg portion of the core 30. 【0036】 Referring to Figure 15, Figure 15 is a perspective view showing a magnetic member 3 according to another embodiment of the present invention. 【0037】 As shown in Figure 15, the tip of the V-shaped recess 302 may have a radius R greater than 5, in which case it is avoided that the V-shaped recess 302 is too sharp and affects the strength of the plate portion 300. For example, when the radius R is 0.8, the maximum thermal stress corresponding to the V-shaped recess 302 is 85.6 MPa, but when the radius R is 5, the maximum thermal stress corresponding to the V-shaped recess 302 is reduced to 64.3 MPa. The core 30 having the V-shaped recess 302 and radius R is not limited to a particular application and may be applied to other embodiments. 【0038】 As described above, in one embodiment, at least one non-jointed region may be located on the inner leg or at least two outer legs, and at least a portion of the at least one non-jointed region may not be covered with a thermally conductive filler. This allows the inner leg or at least two outer legs having the non-jointed region to deform freely even as the temperature difference (or maximum temperature) of the core increases, thereby reducing the thermal stress of the core and suppressing the increase in core loss. In yet another embodiment, at least one non-jointed region may be located on at least two outer legs, and the thermally conductive filler may cover at least one non-jointed region and / or the jointed region located on the inner leg. Similarly, the at least two outer legs having the non-jointed region can deform freely even as the temperature difference (or maximum temperature) of the core increases, thereby reducing the thermal stress of the core and suppressing the increase in core loss. It should be noted here that the temperature difference refers to the temperature difference at the same time between two different locations on the core. In another embodiment, the coils and spacers may be stacked on top of each other and sleeve-fixed directly to the inner legs of the core, eliminating the need to wind the coils on a bobbin. In this case, the insulation and heat dissipation effects between the primary and secondary coils, and between the coils and the core, are improved. Thus, the magnetic members do not need to be limited by the size and spacing of the bobbins, the spacers may be in close contact with the coils, or the structure of the coil cover may extend between the two coils, fixing the distance and spacing between the spacers and coils to a minimum, thereby minimizing the size of the magnetic members. 【0039】 It will be readily apparent to those skilled in the art that many modifications and changes to the apparatus and method are possible while maintaining the teachings of the present invention. Therefore, the above disclosure should be understood to be limited only to the boundaries of the appended claims. [Explanation of Symbols] 【0040】 1 Magnetic member 10 cores 12 coils 14 Thermally conductive fillers 100 Medial leg 102 Outer leg 104 Non-bonded area 106 Joint area

Claims

[Claim 1] A magnetic material, A core having an inner leg and at least two outer legs, At least one spacer, At least two coils, wherein the at least two coils and the at least one spacer are stacked on top of each other and sleeved directly to the inner leg portion, A coil cover, wherein the inner leg portion is directly sleeve-fixed and the coil cover is stacked on the spacer and the at least two coils, It has, The coil cover has guide grooves corresponding to the outlet ends of the at least two coils, The coil cover is a magnetic member configured to lead out the lead ends of at least two coils from the core through the guide grooves of the coil cover. [Claim 2] Each of the at least two coils is formed by winding a wire covered with at least three staggered layers of insulating tape, The insulating tape is laminated in a staggered manner from the first layer to at least the second or third layer. The magnetic member according to claim 1, wherein the overlap ratio W2 / W1 of the displacement is greater than 67%, where W1 represents the width of the insulating tape and W2 represents the overlapping width. [Claim 3] Furthermore, it has a thermally conductive filler, The magnetic member according to claim 1, wherein the thermally conductive filler covers a portion of the core and fills the gap between two opposing laminated surfaces of the at least two coils. [Claim 4] The magnetic member according to claim 3, wherein the thermally conductive filler is filled into the opposing surfaces between the inner leg portion and the at least two coils. [Claim 5] The magnetic member according to claim 3, wherein the thermally conductive filler covers the outer surfaces of the at least two coils and the at least one spacer. [Claim 6] The magnetic member according to claim 1, wherein the winding structure of each of the at least two coils is derived from the outside of the upper layer and the outside of the lower layer. [Claim 7] The at least one spacer further has a guide groove corresponding to the guide groove of the coil cover, The magnetic member according to claim 1, wherein the lead end of the coil is led out from the core via the guide groove of the coil cover and the guide groove of the spacer. [Claim 8] The magnetic member according to claim 7, wherein the structure of the coil cover extends between the at least two coils and fixes the distance between the at least one spacer and the at least two coils to a minimum. [Claim 9] The magnetic member according to claim 1, wherein the material of the at least one spacer is electrically insulating and magnetically permeable. [Claim 10] The magnetic member according to claim 1, wherein the magnetic member does not have a bobbin covering the inner leg portion. [Claim 11] The magnetic member according to claim 1, wherein the core has a plate portion, and a V-shaped recess is formed at the end of the plate portion. [Claim 12] The magnetic member according to claim 11, wherein the arrangement of the joint between the two ends of the V-shaped recess corresponds to the inner leg portion. [Claim 13] The magnetic member according to claim 11, wherein the tip of the V-shaped recess has a radius greater than 5 mm. [Claim 14] Furthermore, it has a heat dissipation member arranged on the core, The magnetic member according to claim 1, wherein the heat dissipation member is in contact with the upper surface and the side surface of the core. [Claim 15] The magnetic member according to claim 14, wherein the heat dissipation member is L-shaped, and the length of the portion of the heat dissipation member that contacts the side surface of the core is less than the height of the core. [Claim 16] The magnetic member according to claim 14, wherein the heat dissipation member is bonded to the core with an adhesive having a Shore D or Shore A hardness of less than 80. [Claim 17] The aforementioned at least two coils include a primary coil and a secondary coil, The magnetic member according to claim 1, wherein the at least one spacer has a ring-shaped structure disposed between the primary coil and the secondary coil.

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