Magnetic member

Abstract

To provide a magnetic member that can reduce the thermal stress of a core.SOLUTION: A magnetic member includes: a core that includes an inner leg part and at least two outer leg parts; at least one spacer; and at least two coils, wherein the at least two coils and the at least one spacer are stacked with each other and directly sleeved on the inner leg part. Each of the at least two coils is formed by winding a wire covered by at least three misaligned layers of insulating tape.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic member, and more particularly to a magnetic member capable of reducing thermal stress in a core. [Background technology]

[0002] In response to the demand for fast charging of electric vehicles, the operating power is increasingly rising, and the heat generated by electronic components is gradually increasing. The magnetic components of the on-board charger (OBC), such as the transformer, will generate heat due to losses during operation, and the uneven heat will cause additional thermal stress on the transformer core. The thermal stress will increase the losses in the transformer core, and the heat will not converge under continuous cycles, resulting in excessively high temperatures and losses. As a result, in extreme cases, irreversible damage will occur 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 [Problem to be solved by the invention]

[0004] The present invention has been made to solve the above-mentioned problems, and has an object to provide a magnetic member capable of reducing thermal stress in a core. [Means for solving the problem]

[0005] In one embodiment of the present invention, the magnetic member includes a core, at least one coil, and a thermally conductive filler. The core has an inner leg, at least two outer legs, and at least one non-bonded region. The at least one coil is wound around the inner leg or the 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-bonded region is not covered by the thermally conductive filler.

[0006] In another embodiment of the present invention, the magnetic member has a core, at least one coil, and a thermally conductive filler. The core has an inner leg, at least two outer legs, and at least one non-bonded region. The at least one non-bonded region is disposed on the at least two outer legs. The at least one coil is wound around the inner leg or the at least two outer legs. The thermally conductive filler covers a portion of the core and the at least one non-bonded region disposed on the at least two outer legs.

[0007] In another embodiment of the invention, the magnetic member has a core, a bobbin, at least one coil, and a thermally conductive filler. The core has an inner leg, at least two outer legs, and a plurality of non-bonded regions. The plurality of non-bonded regions are disposed on the inner leg and the at least two outer legs. The bobbin is sleeved on the inner leg. A top surface of the bobbin is bonded to an inner plate surface of the core. The at least one coil is disposed on the bobbin. The thermally conductive filler covers a portion of the core and does not cover the plurality of non-bonded regions.

[0008] In another embodiment of the invention, the magnetic member includes 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 the at least one spacer are stacked on top of each other and sleeved directly onto 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 mentioned above, in one embodiment, at least one non-bonded region may be disposed on the inner leg or at least two outer legs, and at least a portion of the at least one non-bonded region may not be covered with the thermally conductive filler. This allows the inner leg or at least two outer legs having the non-bonded 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 the increase in the loss of the core. Furthermore, in another embodiment, at least one non-bonded region may be disposed on the at least two outer legs, and the thermally conductive filler may cover the at least one non-bonded region. Similarly, the at least two outer legs having the non-bonded region may deform freely even if the temperature difference (or maximum temperature) of the core increases, thereby reducing the thermal stress of the core and suppressing the increase in the loss of the core. In another embodiment, the coil and the spacer may be stacked on each other and sleeved directly on the inner leg of the core, in which case there is no need to wind the coil on a bobbin to improve the insulation and heat dissipation effect between the primary coil and the secondary coil and between the coil and the core. Thus, the magnetic member no longer needs to be limited to the size and spacing of the bobbin, the spacer may be tightly attached to the coil, and the coil cover structure may extend between the two coils, with the distance and spacing between the spacer and the coil fixed to a minimum, minimizing the size of the magnetic member.

[0010] These and other objectives of the present invention will no doubt become apparent to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment which is illustrated in the various drawing figures. [Brief description of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a magnetic member according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Diagram 3]FIG. 3 is an exploded view showing the spacer, coil cover, and two coils shown in FIG. 2. [Figure 4] FIG. 1 is a schematic diagram showing four spacers of different shapes. [Diagram 5] FIG. 1 is a schematic diagram showing a wire covered with three staggered layers of insulating tape. [Figure 6] FIG. 4 is a perspective view showing a magnetic member according to another embodiment of the present invention. [Figure 7] FIG. 7 is a cross-sectional view showing the magnetic member shown in FIG. [Figure 8] 7 is another cross-sectional view showing the magnetic member shown in FIG. 6. [Figure 9] FIG. 8 is a perspective view showing the bobbin shown in FIG. [Figure 10] FIG. 10 is a top view showing the bobbin shown in FIG. [Figure 11] FIG. 4 is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Figure 12] FIG. 4 is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Figure 13] FIG. 4 is a cross-sectional view showing a magnetic member according to another embodiment of the present invention. [Figure 14] FIG. 4 is a perspective view showing a magnetic member according to another embodiment of the present invention. [Figure 15] FIG. 4 is a perspective view showing a magnetic member according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 member. As shown in FIG. 1, the magnetic member 1 has a core 10, at least one coil 12, and a thermally conductive filler 14. The core 10 has an inner leg 100, at least two outer legs 102, at least one non-bonded region 104, and at least one bonded region 106. In this embodiment, the core 10 may have a first core member 10a and a second core member 10b, and the inner leg 100 may be 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 UI core, an EI 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 the actual application, and therefore the present invention is not limited to the illustrated embodiment.

[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 with the second core member 10b to form a joining region 106. Furthermore, the second core member 10b is not joined with the two outer legs 102, and two non-joining 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 round wire, a rectangular wire, or a multi-stranded wire.

[0015] In this embodiment, the core 10 is disposed in the casing 16, and the thermally conductive filler 14 is filled in the casing 16, so that the thermally conductive filler 14 may cover a part of the core 10. At this time, at least a part of at least one non-bonded region 104 is not covered by the thermally conductive filler 14. As shown in FIG. 1, the two non-bonded regions 104 and the bonded region 106 are not covered by the thermally conductive filler 14. This allows the two outer legs 102 having the two non-bonded regions 104 to deform freely even if the temperature difference (or maximum temperature) of the core 10 increases, reducing the thermal stress of the core 10 and suppressing an increase in loss of the core 10. For example, in the case of an inductor or transformer having 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 may not be covered by the thermally 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] 2 to 5, FIG. 2 is a cross-sectional view of a magnetic member 1 according to another embodiment of the present invention, FIG. 3 is an exploded view of a spacer 18, a coil cover 19, and two coils 12 shown in FIG. 2, FIG. 4 is a schematic diagram of four spacers 18 with different shapes, and FIG. 5 is a schematic diagram of a wire 122 covered by three staggered layers of insulating tape 120. In some implementations, 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 with plastic, or may be formed of a magnetic material (e.g., ferrite), or may be formed of a material (e.g., ceramic) having high thermal conductivity and electrical insulation. In this embodiment, the at least one coil 12 may have a primary coil 12a and a secondary coil 12b, and the cross section may be circular, elliptical, or rectangular. A rectangular shape may effectively improve the volume utilization rate. As shown in FIG. 4, the spacer 18 may have a ring-shaped (e.g., circular, elliptical, semicircular, or semi-elliptical) structure disposed 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 further have a coil cover 19 that is sleeve-fixed directly to the inner leg 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 end of the coil 12 out of the core 10 via a guide groove 19a. In this embodiment, the coil cover 19 is electrically insulated. In this embodiment, the spacer 18 further has a guide groove 18b that corresponds 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 sleeve-fixed directly to the inner leg 100 of the core 10, the end of the coil 12 is 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 FIG. 2 and FIG. 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 the at least one spacer 18 are stacked together and sleeved directly onto the inner leg 100. In this embodiment, the magnetic member 1 is configured by stacking the spacer 18, the coil cover 19, and the two coils 12 together. The coils 12 do not need to be wound on a bobbin. After the coils 12 are wound on the air coil, the coils 12 and the spacer 18 are stacked together and sleeved directly onto the inner leg 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 (outer-outer winding), which has better flatness, unlike another winding structure derived from the inside (inner-outer winding). Therefore, the magnetic member 1 does not need to be limited to the size and spacing of the bobbin, and 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, and the distance and gap between the spacer 18 and the coil 12 may be fixed to a minimum, minimizing the size of the magnetic member 1. Also, 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 (e.g., a coil cover and bobbin with a covering wall) that covers the inner leg 100, and good heat dissipation is obtained. 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 stacking surfaces of the two coils 12 is filled with the thermally conductive filler 14, the thermally conductive filler 14 is filled on the opposing surfaces between the inner leg 100 and the two coils 12, and the thermally conductive filler 14 may further cover the outer surfaces of the two coils 12 and the spacer 18, so that the heat dissipation surface of the two coils 12 is increased and a good heat dissipation effect can be obtained. In an embodiment in which the thermally conductive filler 14 is not present, the spacer and the coils are not sleeved onto the bobbin, so that the air flow can easily flow into the spacer 18, the coil cover 19, and the two coils 12, and a good heat dissipation effect can be obtained.In some embodiments, to maintain the same insulation between the two coils 12 and between the two coils 12 and the bobbin-less 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 FIG. 5). A single insulating tape 120 may be staggered and laminated from the first layer to at least the second or third layer, with the staggered overlap ratio W2 / W1 being 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 a polyimide film. Preferably, the single wire 122 or the multiple wires 122 are enameled wires covered with an insulating layer.

[0019] Referring to Figures 6 to 10, Figure 6 is an oblique 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 an oblique 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 the magnetic member 1' and the above-mentioned magnetic member 1 is that the magnetic member 1' further comprises a bobbin 20 and the inner leg 100 further comprises a floating portion 1000, as shown in Figs. 6 to 9. In this embodiment, the ratio T of the floating portion 1000 to the inner leg 100 may be 50%, or 2% to 95%. To further explain, the inner leg 100 has a length X1, and the floating portion 1000 has a length X2, so that the ratio T of the floating portion 1000 to the inner leg 100 is X2 / X1. The bobbin 20 is sleeve-fixed to the inner leg 100, and at least one coil 12 is disposed on the bobbin 20. Thus, the coil 12 is still wound on the inner leg 100. In this embodiment, the interior of the bobbin 20 has a protruding platform 200 on which the floating portion 1000 of the inner leg 100 is supported, and the floating portion 1000 is disposed between the first core member 10a and the second core member 10b. In this embodiment, the protruding platform 200 extends from the outside to the inside of the inner leg 100, and the floating portion 1000 may be supported.

[0021] In this embodiment, the first core member 10a and the second core member 10b are joined together at the two outer legs 102 to form two joining regions 106. Also, the second core member 10b is not joined to the floating part 1000, which is supported by the protruding platform 200, and the two non-joining regions 104a, 104b are disposed on opposite sides of the floating part 1000. After the thermally conductive filler 14 is filled into the casing 16, one of the two non-joining regions 104a, 104b is not (completely) covered by the thermally conductive filler 14. As shown in FIG. 7, the non-joining region 104a below the floating part 1000 and the two joining regions 106 are covered by the thermally conductive filler 14, and the non-joining region 104b above the floating part 1000 is not covered by the thermally conductive filler 14. This allows the inner leg 100 having the non-bonded region 104b to deform freely even while the temperature difference (or maximum temperature) of the core 10 increases, reducing thermal stress in the core 10 and suppressing an increase in loss in the core 10.

[0022] In this embodiment, the height H1 of the thermally conductive filler 14 is equal to or smaller than the height H2 of the bobbin 20, and the thermally conductive filler 14 does not contact the bottom surface of the second core member 10b. Therefore, the thermal expansion stress of the thermally conductive filler 14 is greatly suppressed, and the second core member 10b and the inner leg 100 do not interact with each other due to the high thermal stress caused by the thermally conductive filler 14, thereby reducing the temperature difference (or maximum temperature) of the core 10. Therefore, the thermal stress of the core 10 can be reduced, and an increase in loss of the core 10 is suppressed.

[0023] As shown in Fig. 7 and Fig. 9, at least one hole 202 is formed in the bobbin 20, so that the thermally conductive filler 14 can contact the inside of the at least one coil 12, and the contact area between the thermally conductive filler 14 and the inner leg 100 is increased, so that the heat dissipation path is increased, and the temperature difference (or the maximum temperature) is effectively reduced, and the additional loss due to heat is reduced. In this embodiment, one of the at least one hole 202 extends from the upper plate 204 of the bobbin 20 to the lower plate 206 of the bobbin 20, and one boundary of the at least one hole 202 may overlap the upper plate 204 and the lower plate 206 of the bobbin 20. As shown in Fig. 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 boundaries 202c of each hole 202b may overlap at 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 easily into the bobbin 20, and more heat may be conducted from the coil 12. Also, the number of molds for manufacturing (injection molding) the bobbin 20 may be reduced, thereby reducing costs.

[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 less likely 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 FIG. 6 and FIG. 7, the magnetic member 1' may further include 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 include, but is not limited to, two heat dissipation members 22 disposed on opposite sides of the core 10. In this embodiment, the heat dissipation member 22 may be L-shaped, and the length L of the part of the heat dissipation member 22 that contacts the side surface S2 of the core 10 may be smaller than the height H3 of the core 10. This allows the heat dissipation member 22 to continue to be in contact with the upper surface S1 of the core 10 without any gap even if there is a tolerance variation in the height of the core 10, thereby improving heat dissipation. In addition, since 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 process with a large tolerance at low cost. 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 may cover a part of the heat dissipation member 22, and the heat dissipation member 22 may be able to transfer heat to the bottom. Furthermore, the heat dissipation member 22 may be bonded to the core 10 by an adhesive with a small Shore D or Shore A hardness less than 80, so as to reduce the temperature difference (or maximum temperature) of the core 10 and reduce the thermal stress. For example, if Shore D>80, the corresponding maximum temperature of the core 10 may be 59.3°C, and if Shore D<80, the corresponding maximum temperature of the core 10 may be reduced to 50.6°C.

[0027] Please refer to FIG. 11, which is a cross-sectional view of a magnetic member 1'' according to another embodiment of the present invention.

[0028] The main difference between the magnetic member 1'' and the magnetic member 1 described above is that in addition to the first core member 10a and the second core member 10b, the magnetic member 1'' further includes a third core member 10c. As shown in FIG. 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. In addition, the two adjacent side walls 108a, 108b of the first core member 10a and the second core member 10b are not joined to each other, and the non-joining region 104a is disposed between the two adjacent side walls 108a, 108b of the first core member 10a and the second core member 10b. In this embodiment, the two adjacent side walls 108a, 108b form a part of the inner leg 100. The inner leg 100 of the third core member 10c and the inner leg 100 of the first core member 10a and the second core member 10b are disposed relative to each other but are not joined to form another non-joined region 104b. The inner leg 100 of the third core member 10c is integrally formed without a gap. Two adjacent side walls 108a, 108b of the first core member 10a and the second core member 10b face each other at the inner leg 100.

[0029] After the thermally conductive filler 14 is filled in the casing 16, at least a part of the non-bonded region 104a is not covered by the thermally conductive filler 14. As shown in FIG. 11, the lower part of the non-bonded region 108a between the two adjacent side walls 104a, 108b and the two bonded regions 106 are covered by the thermally conductive filler 14, and the upper part of the non-bonded region 104a is not covered by the thermally conductive filler 14. In addition, the non-bonded region 104b above the inner leg 100 of the third core member 10c is covered by the thermally conductive filler 14. This allows the inner leg 100 having the upper part of the non-bonded region 104a to freely deform even if the temperature difference (or the maximum temperature) of the core 10 increases, and the thermal stress of the core 10 may be reduced, and an increase in loss of the core 10 may be suppressed. 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] Reference is now made to FIG. 12, which is a cross-sectional view showing a magnetic member 1''' according to another embodiment of the present invention.

[0031] The main difference between the magnetic member 1''' and the aforementioned magnetic member 1 is that, as shown in FIG. 12, the thermally conductive filler 14 covers at least one non-bonded region 104, and at least one non-bonded region 104 is disposed on at least two outer legs 102, and at least one bonded region 106 is disposed on the inner leg 100. In this embodiment, the first core member 10a and the second core member 10b are two of E core, PQ core, T core, UU core, U core, UI core, EI core, I core or F core, and two non-bonded regions 104 are disposed on the two outer legs 102, and one bonded region 106 is disposed on the inner leg 100. In other words, the two outer legs 102 of the core 10 are not bonded, and the inner leg 100 of the core 10 is bonded. After the thermally conductive filler 14 is filled in the casing 16, the thermally conductive filler 14 covers a part of the core 10, two non-bonded regions 104 disposed in the two outer legs 102, and a bonded region 106 disposed in the inner leg 100. This allows the two outer legs 102 having the non-bonded regions 104 to deform freely even if the temperature difference (or maximum temperature) of the core 10 increases, reducing the thermal stress of the core 10 and suppressing an increase in loss of the core 10. For example, when the magnetic member 1''' is an inductor or transformer having a power of 6.6KW, the maximum thermal stress can be reduced from 68MPa to 32.4MPa, and the maximum temperature of the core 10 can be reduced from 154℃ to 115.2℃.

[0032] Reference is now made to FIG. 13, which is a cross-sectional view showing a magnetic member 1'''' according to another embodiment of the present invention.

[0033] The main difference between the magnetic member 1'''' and the above-mentioned magnetic member 1 is that, in addition to the core 10, at least one coil 12, and the thermally conductive filler 14, the magnetic member 1'''' further includes a bobbin 20'', as shown in FIG. 13. The core 10 has an inner leg 100, at least two outer legs 102, and a plurality of non-bonded regions 104. The plurality of non-bonded regions 104 are disposed on the inner leg 100 and the at least two outer legs 102. The bobbin 20' is sleeve-fixed to the inner leg 100. The upper surface 208 of the bobbin 20' may be bonded to the inner plate surface 110 of the core 10 by an adhesive. At least one coil 12 is disposed on the bobbin 20'. After the thermally conductive filler 14 is filled in the casing 16, the thermally conductive filler 14 covers a portion of the core 10 but does not cover the plurality of non-bonded regions 104. As a result, even if the temperature difference (or maximum temperature) of the core 10 increases, the inner leg 100 and the at least two outer legs 102 having the multiple non-bonded regions 104 can freely deform, reducing thermal stress in the core 10 and suppressing an increase in loss in the core 10. 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 an adhesive, and the two inner plate surfaces 110, 112 are opposed to each other.

[0034] Reference is now made to FIG. 14, which is a perspective view showing a magnetic member 3 according to another embodiment of the present invention.

[0035] 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 without a discontinuous geometric structure, and stress concentration is avoided. In this embodiment, the position of the junction between the two ends of the V-shaped recess 302 may correspond to the inner leg of the core 30.

[0036] Reference is now made to FIG. 15, which is a perspective view showing a magnetic member 3 according to another embodiment of the present invention.

[0037] 15, the tip of the V-shaped recess 302 may have a radius R greater than 5, in which case the V-shaped recess 302 is prevented from being too sharp and affecting 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 the radius R is not limited to a specific application and may be applied to another embodiment.

[0038] As mentioned above, in one embodiment, at least one non-bonded region may be disposed on the inner leg or at least two outer legs, and at least a part of the at least one non-bonded region may not be covered by the thermally conductive filler. In this way, even if the temperature difference (or the maximum temperature) of the core increases, the inner leg or at least two outer legs having the non-bonded region can freely deform, and the thermal stress of the core can be reduced and the increase in loss of the core can be suppressed. In yet another embodiment, at least one non-bonded region may be disposed on at least two outer legs, and the thermally conductive filler may cover the at least one non-bonded region and / or the bonded region disposed on the inner leg. Similarly, the at least two outer legs having the non-bonded region can freely deform even if the temperature difference (or the maximum temperature) of the core increases, and as a result, the thermal stress of the core can be reduced and the increase in loss of the core can be suppressed. It should be noted here that the temperature difference refers to the temperature difference between two different positions of the core at the same time. In another embodiment, the coil and spacer may be stacked on each other and sleeved directly on the inner leg of the core, and the coil does not need to be wound on the bobbin, in which case the effect of insulation and heat dissipation between the primary coil and the secondary coil and between the coil and the core is improved. Therefore, the magnetic member does not need to be limited to the size and spacing of the bobbin, and the spacer may be tightly attached to the coil, or the structure of the coil cover may extend between the two coils, and the distance and spacing between the spacer and the coil may be fixed to a minimum, minimizing the size of the magnetic member.

[0039] Those skilled in the art will readily appreciate that numerous modifications and variations of the apparatus and method may be made while retaining the teachings of this invention, and therefore the above disclosure should be construed as limited only by the metes and bounds of the appended claims. [Explanation of symbols]

[0040] 1 Magnetic material 10 cores 12 Coils 14 Thermally conductive filler 100 Medial leg 102 Outer leg 104 Non-bonded area 106 Joint area

Claims

1. A magnetic member, a core having an inner leg and at least two outer legs; At least one spacer; at least two coils, the at least two coils and the at least one spacer being stacked on top of one another and sleeved directly onto the inner leg; having A magnetic member, wherein each of the at least two coils is formed by winding a wire covered with at least three staggered layers of insulating tape.

2. 2. The magnetic component of claim 1, wherein the insulating tape is stacked with a stagger from the first layer to at least the second layer or the third layer, and the stagger overlap ratio W2 / W1 is greater than 67%, where W1 represents the width of the insulating tape and W2 represents the overlap width.

3. Further, the thermally conductive filler is contained, 10. The magnetic component of claim 1, wherein the thermally conductive filler covers a portion of the core and fills a gap between two opposing lamination surfaces of the at least two coils.

4. The magnetic component of claim 3 , wherein the thermally conductive filler is filled on opposing surfaces between the inner leg and the at least two coils.

5. The magnetic member of claim 3 , wherein the thermally conductive filler coats an outer surface of the at least two coils and the at least one spacer.

6. The magnetic member of claim 1 , wherein the winding structure of each of the at least two coils is routed from an outside of an upper layer and an outside of a lower layer.

7. a coil cover sleeved directly onto the inner leg and layered over the at least one spacer and the at least two coils; The at least one spacer further has a guide groove corresponding to the guide groove of the coil cover, 2. The magnetic member according to claim 1, wherein an end of the coil is led out from the core via a guide groove of the coil cover and a guide groove of the spacer.

8. 8. The magnetic member of claim 7, wherein the coil cover structure extends between the at least two coils and fixes a minimum distance between the at least one spacer and the at least two coils.

9. 10. The magnetic member of claim 1, wherein a material of the at least one spacer is electrically insulating and magnetically permeable.

10. 10. The magnetic member of claim 1, wherein the magnetic member does not have a bobbin covering the inner leg.

11. 2. The magnetic member according to claim 1, wherein the core has a plate portion, and a V-shaped recess is formed at an end of the plate portion.

12. The magnetic member of claim 11, wherein a location of a joint between two ends of the V-shaped recess corresponds to the inner leg.

13. The magnetic member according to claim 11 , wherein the tip of the V-shaped recess has a radius greater than 5.

14. Further, a heat dissipation member is disposed on the core, 2. The magnetic member according to claim 1, wherein the heat dissipation member is in contact with a top surface and a side surface of the core.

15. 15. The magnetic member according to claim 14, wherein the heat dissipation member is L-shaped, and a length of a portion of the heat dissipation member that contacts the side surface of the core is smaller than a height of the core.

16. 15. The magnetic member according to claim 14, wherein the heat dissipation member is adhered to the core with an adhesive having a Shore D or Shore A hardness of less than 80.

17. the at least two coils include a primary coil and a secondary coil; 10. The magnetic member of claim 1, wherein the at least one spacer comprises a ring-shaped structure disposed between the primary coil and the secondary coil.

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