TWI878981B - Magnetic component - Google Patents

Abstract

A magnetic component includes a core, at least one spacer and at least two coils. The core includes an inner leg and at least two outer legs. The at least two coils and the at least one spacer are stacked with each other and directly sleeved on the inner leg. Each of the at least two coils is formed by winding a wire covered by at least three misaligned layers of insulating tape.

Description

Magnetic components

The present invention relates to a magnetic element, in particular to a magnetic element capable of reducing the thermal stress of a magnetic core.

In response to the demand for fast charging of electric vehicles, the operating power is getting higher and higher, causing the heat generated by the electronic components themselves to increase. The magnetic components of the on-board charger (OBC), such as the transformer, will generate heat due to loss during operation, and the uneven heat will generate additional thermal stress on the transformer's magnetic core, which will increase the transformer's magnetic core loss. Under continuous circulation, the heat will not be able to converge, resulting in excessive temperature and loss, and in severe cases, it will cause irreversible damage and rupture of the magnetic core.

The present invention provides a magnetic element that can reduce the thermal stress of the magnetic core to solve the above problems.

According to one embodiment, the magnetic element of the present invention includes a magnetic core, at least one coil and a thermally conductive filler. The magnetic core includes an inner column, at least two outer columns and at least one non-joining area. At least one coil is wound around the inner column or at least two outer columns. The thermally conductive filler covers a portion of the magnetic core. At least a portion of at least one non-joining area is not covered by the thermally conductive filler.

According to another embodiment, the magnetic element of the present invention includes a magnetic core, at least one coil and a thermally conductive filler. The magnetic core includes an inner column, at least two outer columns and at least one non-bonding area. The at least one non-bonding area is located at at least two outer columns. At least one coil is wound around the inner column or at least two outer columns. The thermally conductive filler covers a portion of the magnetic core and at least one non-bonding area located at at least two outer columns.

According to another embodiment, the magnetic element of the present invention includes a magnetic core, a bracket, at least one coil and a thermal conductive filler. The magnetic core includes an inner column, at least two outer columns and a plurality of non-joining areas. The plurality of non-joining areas are located at the inner column and at least two outer columns. The bracket is sleeved on the inner column. An upper surface of the bracket is joined to an inner plate surface of the magnetic core. At least one coil is disposed on the bracket. The thermal conductive filler covers a portion of the magnetic core and does not cover the plurality of non-joining areas.

According to another embodiment, the magnetic element of the present invention comprises a magnetic core, at least one partition and at least two coils. The magnetic core comprises an inner column and at least two outer columns. The at least two coils and at least one partition are stacked on each other and directly sleeved on the inner column. Each coil is wound by a wire with at least three layers of insulation strip staggered coating.

In summary, in one embodiment, at least one non-bonding area may be located at the inner column or at least two outer columns, and at least a portion of at least one non-bonding area may not be covered by a thermally conductive filler. Thus, the inner column or at least two outer columns having a non-bonding area can be freely deformed when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding an increase in the loss of the magnetic core. In addition, in another embodiment, at least one non-bonding area may be located at at least two outer columns, and a thermally conductive filler may cover at least one non-bonding area. Similarly, at least two outer columns having a non-bonding area can be freely deformed when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding an increase in the loss of the magnetic core. In another embodiment, the coil and the partition can be stacked and directly sleeved on the inner column of the magnetic core, so that the coil does not need to be wrapped around the bracket, and the insulation and heat dissipation effect between the primary coil and the secondary coil, and between the coil and the magnetic core can be improved. In this way, the magnetic element will not be limited by the size and space of the bracket, and the partition can be in close contact with the coil, or the lead cover structure can be extended between the two coils to fix and minimize the distance and gap between the partition and the coil, so as to miniaturize the size of the magnetic element.

The advantages and spirit of the present invention can be further understood through the following detailed description of the invention and the attached drawings.

1,1',1",1''',1'''',3: Magnetic components

10,30: Magnetic core

10a: First core

10b: Second core

10c: The third core

12: Coil

12a: Primary coil

12b: Secondary coil

14: Thermal conductive filler

16: Shell

18: Partition

18a: Gap

18b,19a: Wire duct

19: Lead cover

20,20': Bracket

22: Heat sink

100: Inner column

102: Outer column

104,104a,104b: Non-joint area

106: Junction area

108a,108b: Side wall

110,112: Inner panel surface

120: Insulation zone

122: Conductor wire

200: Boss

202,202a,202b: Holes

202c:Border

204: Go up

206: Lower board

208: Upper surface

210: Lower surface

300: Board

302: V-groove

1000: Suspended part

H1,H2,H3:Height

L, X1, X2: length

R: radians

S1: Top surface

S2: Side

W1,W2: Width

Figure 1 is a cross-sectional view of a magnetic element according to an embodiment of the present invention.

Figure 2 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

Figure 3 is an exploded view of the partition, lead cover and second coil in Figure 2.

Figure 4 is a schematic diagram of four partitions with different shapes.

Figure 5 is a schematic diagram of a conductor with three layers of insulation tape wrapped in an offset manner.

Figure 6 is a three-dimensional diagram of a magnetic element according to another embodiment of the present invention.

Figure 7 is a cross-sectional view of the magnetic element in Figure 6.

Figure 8 is another cross-sectional view of the magnetic element in Figure 6.

Figure 9 is a three-dimensional image of the bracket in Figure 7.

Figure 10 is a top view of the bracket in Figure 9.

Figure 11 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

Figure 12 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

Figure 13 is a cross-sectional view of a magnetic element according to another embodiment of the present invention.

Figure 14 is a three-dimensional diagram of a magnetic element according to another embodiment of the present invention.

Figure 15 is a three-dimensional diagram of a magnetic element according to another embodiment of the present invention.

Please refer to Figure 1, which is a cross-sectional view of a magnetic element 1 according to an embodiment of the present invention.

The magnetic element 1 of the present invention can be a reactor, a transformer, an inductor or other magnetic elements. As shown in FIG. 1 , the magnetic element 1 includes a magnetic core 10, at least one coil 12 and a thermally conductive filler 14. The magnetic core 10 includes an inner column 100, at least two outer columns 102, at least one non-joining area 104 and at least one joining area 106. In this embodiment, the magnetic core 10 can include a first core 10a and a second core 10b, wherein the inner column 100 can be a middle column extending from the first core 10a, and the two outer columns 102 can be side columns extending from the periphery of the first core 10a. Therefore, in this embodiment, the first core 10a can be an E-type magnetic core, a PQ-type magnetic core, a T-type magnetic core or an F-type magnetic core, and the second core 10b can be an I-type magnetic core, a UU-type magnetic core, a U-type magnetic core, a U-I-type magnetic core, an E-I-type magnetic core or an F-type magnetic core. However, the types of the first core 10a and the second core 10b can be determined according to actual applications, and the present invention is not limited to the embodiments shown in the figure.

At least one coil 12 can be wound around the inner column 100 or at least two outer columns 102. In this embodiment, the coil 12 can be wound around the inner column 100, but is not limited thereto. In another embodiment, the coil 12 can also be wound around at least two outer columns 102. In this embodiment, the second core 10b is disposed on the first core 10a, and the inner column 100 and the second core 10b are joined to form a joint area 106. In addition, the second core 10b is not joined to the two outer columns 102, so that two non-joint areas 104 are located between the two outer columns 102 and the second core 10b. The type of the coil 12 can be round wire, rectangular wire or multi-strand wire.

In this embodiment, the magnetic core 10 can be disposed in the housing 16, and the thermal conductive filler 14 can be filled in the housing 16, so that the thermal conductive filler 14 covers a portion of the magnetic core 10. At this time, at least a portion of at least one non-bonding area 104 is not covered by the thermal conductive filler 14. As shown in FIG. 1, the two non-bonding areas 104 and the bonding area 106 are not covered by the thermal conductive filler 14. Thereby, the two outer columns 102 having the two non-bonding areas 104 can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding the increase of the loss of the magnetic core 10. Taking a 6.6KW inductor as an example, the maximum thermal stress can be reduced from 68Mpa to 27Mpa, and the maximum temperature of the magnetic core 10 can be reduced from 154°C to 96°C. It should be noted that one of the inner plate surfaces 110 of the magnetic core 10 may not be covered by the thermal conductive filler 14.

In this embodiment, the thermal conductivity of the thermal conductive filler 14 may be greater than 0.3W/mk, and the material of the thermal conductive filler 14 may include epoxy, silicone, polyurethane (PU), phenolic resins, thermoplastic polyethylene terephthalate (PET), polyamide (PA), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), etc.

Please refer to Figures 2 to 5. Figure 2 is a cross-sectional view of a magnetic element 1 according to another embodiment of the present invention. Figure 3 is an exploded view of the partition 18, the lead cover 19 and the second coil 12 in Figure 2. Figure 4 is a schematic diagram of four partitions 18 with different shapes. Figure 5 is a schematic diagram of a wire 122 covered with three layers of insulating tape 120 in a staggered manner. In some embodiments, the material of the partition 18 has magnetic permeability and electrical insulation, or thermal conductivity and electrical insulation. For example, the partition 18 can be formed by injection molding after mixing magnetic powder and plastic, or by using a magnetic body (such as Ferrite), or by using a high thermal conductivity and electrical insulation (such as a ceramic material). In this embodiment, at least one coil 12 may include a primary coil 12a and a secondary coil 12b, and the cross-section thereof may be circular, elliptical or rectangular, wherein the rectangular shape may effectively improve the volume utilization. As shown in FIG. 4 , the partition 18 may include an annular structure (e.g., circular, elliptical, semicircular or semi-elliptical) disposed between the primary coil 12a and the secondary coil 12b. In this way, the leakage inductance (Lk) and the power density may be increased. In addition, the magnetic element 1 may further include a lead cover 19, which is directly sleeved on the inner column 100 of the magnetic core 10 and stacked above the partition 18 and the two coils 12, so as to lead the end wire of the coil 12 out of the magnetic core 10 through the wire groove 19a of the lead cover 19. In this embodiment, the lead cover 19 is an electrically insulating material. In this embodiment, the partition 18 further includes a wire groove 18b corresponding to the wire groove 19a of the lead cover 19. When the partition 18, the lead cover 19 and the two coils 12 are stacked on each other and directly sleeved on the inner column 100 of the magnetic core 10, the end wire of the coil 12 will be led out of the magnetic core 10 through the wire groove 19a of the lead cover 19 and the wire groove 18b of the partition 18.

As shown in FIG. 2 and FIG. 3, the magnetic element 1 may include a magnetic core 10, at least one partition 18 and at least two coils 12, wherein the at least two coils 12 and the at least one partition 18 are stacked on each other and directly sleeved on the inner column 100. In this embodiment, the magnetic element 1 may include a partition 18, a lead cover 19 and two coils 12 stacked on each other. The coil 12 does not need to be wound around the bracket. After the coil 12 is wound into an air coil, the coil 12 and the partition 18 can be stacked on each other and directly sleeved on the inner column 100 of the magnetic core 10. In this embodiment, the winding structure of the coil 12 is composed of two layers of outer wires (outside-outside winding), which is different from the winding structure of the inner wires (inside-outside winding), and has better flatness. Thus, the magnetic element 1 will not be limited by the size and space of the bracket, and the partition 18 can be in close contact with the coil 12, or the lead cover 19 can be used to extend between the two coils 12 to fix and minimize the distance and gap between the partition 18 and the coil 12, so as to miniaturize the size of the magnetic element 1. Since the space and size of the magnetic element 1 can be miniaturized, the heat dissipation path can be shortened and there is no (winding) bracket and lead cover of the structure covering the inner column to obtain a good heat dissipation effect. In this embodiment, the partition 18 has a gap 18a. When the partition 18 and the second coil 12 are stacked, the thermally conductive filler 14 can fill the gap 18a between the relatively overlapping surfaces of the second coil 12 and the relatively opposite surfaces between the inner column and the second coil 12. The thermally conductive filler 14 can also cover the outward surfaces of the second coil 12 and the partition 18, so that the heat dissipation surface of the second coil 12 is increased, thereby obtaining a good heat dissipation effect. In some embodiments, the thermally conductive filler 14 is not included. In the case of a bracket without a partition and a coil, the airflow is easier to enter the partition 18, the lead cover 19 and the second coil 12, and a good heat dissipation effect can be obtained. In some embodiments, in order to maintain the same insulation between the two coils 12 and between the two coils 12 and the magnetic core 10 without a support, the two coils 12 are wound by at least three layers of insulating tape 120 staggeredly wrapped with a conductor 122 (as shown in FIG. 5 ). A single insulating tape 120 is staggeredly stacked from the first layer to at least the second and third layers, and the staggered overlap ratio (W2/W1) is greater than 67%, where W1 is the width of the single insulating tape 120, and W2 is the overlap width. The insulating tape 120 can be made of PI insulating film (Polyimide Film). The single wire 122 or the multiple wires 122 are preferably enameled wires covered with an insulating layer.

Please refer to Figures 6 to 10. Figure 6 is a three-dimensional view of a magnetic element 1' according to another embodiment of the present invention, Figure 7 is a cross-sectional view of the magnetic element 1' in Figure 6, Figure 8 is another cross-sectional view of the magnetic element 1' in Figure 6, Figure 9 is a three-dimensional view of the bracket 20 in Figure 7, and Figure 10 is a top view of the bracket 20 in Figure 9.

The main difference between the magnetic element 1' and the above-mentioned magnetic element 1 is that the magnetic element 1' further includes a bracket 20, and the inner column 100 further includes a suspension portion 1000, as shown in Figures 6 to 9. In this embodiment, the proportion T of the suspension portion 1000 to the inner column 100 can be 50% or 2%~95%. Furthermore, the inner column 100 has a length X1, and the suspension portion 1000 has a length X2, then the proportion T of the suspension portion 1000 to the inner column 100 is X2/X1. The bracket 20 is sleeved on the inner column 100, and at least one coil 12 is disposed on the bracket 20. Therefore, the coil 12 is still wrapped around the inner column 100. In this embodiment, the inner side of the bracket 20 has a boss 200, and the suspended portion 1000 of the inner column 100 is supported on the boss 200, so that the suspended portion 1000 is located between the first core 10a and the second core 10b. In this embodiment, the boss 200 can extend from the outer side of the inner column 100 toward the inner side to support the suspended portion 1000.

In this embodiment, the first core 10a and the second core 10b are bonded to each other at the two outer columns 102 to form two bonding areas 106. In addition, the second core 10b is not bonded to the suspension 1000, and the suspension 1000 is supported on the boss 200, so that the two non-bonding areas 104a, 104b are located on opposite sides of the suspension 1000. After the thermal conductive filler 14 is filled in the shell 16, one of the two non-bonding areas 104a, 104b is not (completely) covered by the thermal conductive filler 14. As shown in FIG. 7, the non-bonding area 104a and the two bonding areas 106 below the suspension 1000 are both covered by the thermal conductive filler 14, and the non-bonding area 104b above the suspension 1000 is not covered by the thermal conductive filler 14. Thus, the inner column 100 having the non-joining area 104b can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding the increase of the loss of the magnetic core 10.

In this embodiment, the height H1 of the thermally conductive filler 14 can be less than or equal to the height H2 of the bracket 20, so that the thermally conductive filler 14 does not contact the bottom surface of the second core 10b. Therefore, the thermal expansion stress of the thermally conductive filler 14 can be greatly reduced, and the second core 10b and the inner column 100 will not interact due to the higher thermal stress of the thermally conductive filler 14, thereby reducing the temperature difference (or maximum temperature) of the magnetic core 10. In this way, the thermal stress of the magnetic core 10 can be reduced, thereby avoiding the increase of the loss of the magnetic core 10.

As shown in FIG. 7 and FIG. 9, at least one hole 202 can be formed on the bracket 20 so that the thermal conductive filler 14 contacts the inner side of at least one coil 12, and increases the contact area between the thermal conductive filler 14 and the inner column 100, thereby increasing the heat dissipation path, effectively reducing the temperature difference (or maximum temperature), and reducing the additional loss caused by heat. In this embodiment, one of the at least one hole 202 can extend from an upper plate 204 of the bracket 20 toward a lower plate 206 of the bracket 20, and the boundary of one of the at least one hole 202 can overlap the upper plate 204 and the lower plate 206 of the bracket 20. As shown in FIG. 9, the at least one hole 202 includes two holes 202a and two holes 202b. The two holes 202b can extend from the upper plate 204 of the bracket 20 toward the lower plate 206 of the bracket 20, and the boundaries 202c of each hole 202b can overlap the upper plate 204 and the lower plate 206, as shown in Figures 9 and 10. In this way, the thermal conductive filler 14 can flow into the bracket 20 more easily to transfer more heat from the coil 12. In addition, the bracket 20 can be manufactured with fewer molds (injection molding) to reduce costs.

For example, when the magnetic element 1' is an inductor or transformer with a power of 5.5KW, and the proportion of the suspension part 1000 to the inner column 100 is 30%, the maximum thermal stress can be reduced from 52Mpa to 28.6Mpa, and the maximum temperature of the magnetic core 10 can be reduced from 110℃ to 87.106℃. Although the temperature of the suspension part 1000 is 128.45℃, the suspension part 1000 is a simple columnar shape and will not crack. If the winding position of the coil with a large cross-sectional area is further considered, the proportion of the suspension part 1000 to the inner column 100 and the winding position of the coil with a large wire diameter are as follows. It should be noted that at least one coil 12 may include a primary coil 12a and a secondary coil 12b, wherein the position of the secondary coil 12b corresponds to the suspension portion 1000, and the position of the primary coil 12a corresponds to the inner column 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. If the cross-sectional area D1 of the primary coil 12a is greater 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 suspension portion 1000 to the inner column 100 may satisfy 50%<T≦95%. If 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 suspension portion 1000 to the inner column 100 can satisfy 2% ≦ T < 50%.

As shown in FIG. 6 and FIG. 7 , the magnetic element 1 ′ may further include a heat sink 22 disposed on the magnetic core 10, wherein the heat sink 22 contacts a top surface S1 and a side surface S2 of the magnetic core 10. In the present embodiment, the magnetic element 1 ′ may include two heat sinks 22 disposed on opposite sides of the magnetic core 10, but is not limited thereto. In the present embodiment, the heat sink 22 may be L-shaped, and the length L of the portion of the heat sink 22 contacting the side surface S2 of the magnetic core 10 may be less than the height H3 of the magnetic core 10. Thus, even if there is a tolerance in the height of the magnetic core 10, the heat sink 22 can maintain contact with the top surface S1 of the magnetic core 10 without a gap, thereby enhancing the heat dissipation effect. In addition, since there are two heat sinks 22 attached to the top surface S1 and the side surface S2, the heat sink 22 can be manufactured by a process with lower cost and higher tolerance. The L-shaped heat sink 22 is not limited in application and can also be applied in other embodiments.

In this embodiment, the thermal conductive filler 14 can cover a portion of the heat sink 22 so that the heat sink 22 can conduct heat to the bottom. In addition, the heat sink 22 can be attached to the magnetic core 10 by a colloid with a Shore D or Shore A hardness less than 80 to reduce the temperature difference (or maximum temperature) of the magnetic core 10 and reduce thermal stress. For example, if the Shore D hardness is greater than 80, the corresponding maximum temperature of the magnetic core 10 can be 59.3°C; if the Shore D hardness is less than 80, the corresponding maximum temperature of the magnetic core 10 can be 50.6°C.

Please refer to Figure 11, which is a cross-sectional view of a magnetic element 1" according to another embodiment of the present invention.

The main difference between the magnetic element 1" and the above-mentioned magnetic element 1 is that, in addition to the first core 10a and the second core 10b, the magnetic element 1" further includes a third core 10c. As shown in Figure 11, the first core 10a and the second core 10b are arranged side by side and are joined to the third core 10c at two outer columns 102 to form a joining area 106. In addition, the two adjacent side walls 108a and 108b of the first core 10a and the second core 10b are not joined to each other, so that the non-joining area 104a is located between the two adjacent side walls 108a and 108b of the first core 10a and the second core 10b. In the present embodiment, the two adjacent side walls 108a and 108b form a part of the inner column 100. The inner column 100 of the third core 10c is arranged opposite to the inner columns 100 of the first core 10a and the second core 10b and is not joined, thereby forming another non-joined area 104b. The inner column 100 of the third core 10c is formed in one piece without a gap. The two adjacent side walls 108a and 108b of the first core 10a and the second core 10b are opposite to each other at the inner column 100.

After the thermally conductive filler 14 is filled in the shell 16, at least a portion of the non-joining area 104a is not covered by the thermally conductive filler 14. As shown in FIG. 11, the lower portion of the non-joining area 104a between the two adjacent side walls 108a and 108b and the two joining areas 106 are covered by the thermally conductive filler 14, and the upper portion of the non-joining area 104a is not covered by the thermally conductive filler 14. In addition, the non-joining area 104b above the inner column 100 of the third core 10c is also covered by the thermally conductive filler 14. Thus, the inner column 100 having the upper portion of the non-joining area 104a can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding an increase in the loss of the magnetic core 10. For example, when the magnetic component 1" is an inductor or transformer with a power of 3.7KW, the maximum thermal stress can be reduced from 48Mpa to 16Mpa, and the maximum temperature of the magnetic core 10 can be reduced from 150℃ to 120℃.

Please refer to Figure 12, which is a cross-sectional view of a magnetic element 1''' according to another embodiment of the present invention.

The main difference between the magnetic element 1''' and the magnetic element 1 mentioned above is that the thermal conductive filler 14 covers at least one non-joining area 104, wherein at least one non-joining area 104 is located at at least two outer columns 102, and at least one joining area 106 is located at the inner column 100, as shown in FIG. 12. In this embodiment, the first core 10a and the second core 10b are two of an E-type magnetic core, a PQ-type magnetic core, a T-type magnetic core, a UU-type magnetic core, a U-type magnetic core, a U-I-type magnetic core, an E-I-type magnetic core, an I-type magnetic core, or an F-type magnetic core, so that two non-joining areas 104 are located at two outer columns 102, and one joining area 106 is located at the inner column 100. In other words, the two outer columns 102 of the magnetic core 10 are not joined, and the inner column 100 of the magnetic core 10 is joined. After the heat conductive filler 14 is filled in the shell 16, the heat conductive filler 14 covers a portion of the magnetic core 10, two non-joining areas 104 located at the two outer columns 102, and the joining area 106 located at the inner column 100. Thus, the two outer columns 102 with the non-joining areas 104 can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding the increase of the loss of the magnetic core 10. For example, when the magnetic element 1''' is an inductor or transformer with a power of 6.6KW, the maximum thermal stress can be reduced from 68Mpa to 32.4Mpa, and the maximum temperature of the magnetic core 10 can be reduced from 154℃ to 115.2℃.

Please refer to Figure 13, which is a cross-sectional view of a magnetic element 1'''' according to another embodiment of the present invention.

The main difference between the magnetic element 1'''' and the above-mentioned magnetic element 1 is that, in addition to the magnetic core 10, at least one coil 12 and the thermally conductive filler 14, the magnetic element 1'''' further includes a bracket 20', as shown in Figure 13. The magnetic core 10 includes an inner column 100, at least two outer columns 102 and a plurality of non-bonding areas 104. The plurality of non-bonding areas 104 are located at the inner column 100 and the at least two outer columns 102. The bracket 20' is sleeved on the inner column 100. An upper surface 208 of the bracket 20' can be bonded to an inner plate surface 110 of the magnetic core 10 by means of a glue. At least one coil 12 is disposed on the bracket 20'. After the thermally conductive filler 14 is filled in the shell 16, the thermally conductive filler 14 covers a portion of the magnetic core 10 and does not cover the plurality of non-bonding areas 104. Thus, the inner column 100 having a plurality of non-bonding areas 104 and at least two outer columns 102 can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core 10 increases, so that the thermal stress of the magnetic core 10 is reduced, thereby avoiding the increase of the loss of the magnetic core 10. In another embodiment, a lower surface 210 of the bracket 20' can be further bonded to another inner plate surface 112 of the magnetic core 10 by means of glue, wherein the two inner plate surfaces 110, 112 are opposite to each other.

Please refer to Figure 14, which is a three-dimensional diagram of the magnetic element 3 according to another embodiment of the present invention.

As shown in FIG. 14 , the magnetic core 30 of the magnetic element 3 has a plate portion 300 and a V-shaped groove 302, wherein the V-shaped groove 302 is formed on one side of the plate portion 300. In this embodiment, the side of the plate portion 300 having the V-shaped groove 302 is a continuous side without a discontinuous geometric structure to avoid stress concentration. In this embodiment, the position of the joint between the two sides of the V-shaped groove 302 corresponds to the inner column of the magnetic core 30.

Please refer to Figure 15, which is a three-dimensional diagram of the magnetic element 3 according to another embodiment of the present invention.

As shown in FIG. 15 , the curvature R of the tip of the V-groove 302 can be greater than 5 to prevent the V-groove 302 from being too sharp and affecting the strength of the plate 300. For example, if the curvature R is 0.8, the maximum thermal stress of the corresponding V-groove 302 can be 85.6MPa; if the curvature R is 5, the maximum thermal stress of the corresponding V-groove 302 can be 64.3MPa. The magnetic core 30 with the V-groove 302 and curvature R is not limited in application and can also be applied in other embodiments.

In summary, in one embodiment, at least one non-bonding area may be located at the inner column or at least two outer columns, and at least a portion of at least one non-bonding area may not be covered by a thermally conductive filler. Thus, the inner column or at least two outer columns having a non-bonding area can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding an increase in the loss of the magnetic core. In addition, in another embodiment, at least one non-bonding area may be located at at least two outer columns, and the thermally conductive filler may cover at least one non-bonding area and/or a bonding area located at the inner column. Similarly, at least two outer columns having a non-bonding area can be deformed freely when the temperature difference (or maximum temperature) of the magnetic core increases, so that the thermal stress of the magnetic core is reduced, thereby avoiding an increase in the loss of the magnetic core. It should be noted that the temperature difference described in this article refers to the temperature difference between two different positions of the magnetic core at the same time. In another embodiment, the coil and the partition can be stacked and directly sleeved on the inner column of the magnetic core, so that the coil does not need to be wrapped around the bracket, and the insulation and heat dissipation effect between the primary coil and the secondary coil, and between the coil and the magnetic core can be improved. In this way, the magnetic element will not be limited by the size and space of the bracket, and the partition can be in close contact with the coil, or the lead cover structure can be extended between the two coils to fix and minimize the distance and gap between the partition and the coil, so as to miniaturize the size of the magnetic element.

The above is only the preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the patent application of the present invention shall fall within the scope of the present invention.

1: Magnetic components

10: Magnetic core

10a: First core

10b: Second core

12: Coil

12a: Primary coil

12b: Secondary coil

14: Thermal conductive filler

18: Partition

19: Lead cover

100: Inner column

Claims (17)

A magnetic element comprises: a magnetic core, comprising an inner column and at least two outer columns; at least one partition; and at least two coils, wherein the at least two coils and the at least one partition are stacked on each other and directly sleeved on the inner column; wherein each coil is wound in a stacked manner by at least three layers of insulating strip staggered coated wires. A magnetic element as described in claim 1, wherein the insulating tape is stacked misaligned from the first layer to at least the second and third layers, and the misaligned overlap ratio W2/W1 is greater than 67%, W1 is the width of the insulating tape, and W2 is the overlap width. The magnetic element as described in claim 1 further comprises a thermally conductive filler that covers a portion of the magnetic core and fills the gap between the relatively overlapping surfaces of the at least two coils. A magnetic element as described in claim 3, wherein the thermally conductive filler is filled into the surfaces facing each other between the inner column and the at least two coils. A magnetic element as described in claim 3, wherein the thermally conductive filler covers the outward surface of the at least two coils and the at least one partition. As described in claim 1, the winding structure of each coil is composed of two layers of wires extending from the outside. The magnetic element as described in claim 1 further comprises a lead cover, which is directly sleeved on the inner column and stacked above the at least one partition and the at least two coils, and the at least one partition further comprises a wire groove corresponding to a wire groove of the lead cover, and the end wire of the coil is led out of the magnetic core through the wire groove of the lead cover and the wire groove of the partition. A magnetic element as described in claim 7, wherein the structure of the lead cover extends between the at least two coils to fix and minimize the distance between the at least one partition and the at least two coils. A magnetic element as described in claim 1, wherein the material of at least one partition has magnetic permeability and electrical insulation. A magnetic element as described in claim 1, wherein the magnetic element does not cover the bracket of the inner column. A magnetic element as described in claim 1, wherein the magnetic core has a plate portion and a V-shaped groove, and the V-shaped groove is formed on one side of the plate portion. A magnetic element as described in claim 11, wherein the position of the junction between the two sides of the V-shaped groove corresponds to the inner column. A magnetic element as described in claim 11, wherein the curvature of the tip of the V-shaped groove is greater than 5. The magnetic element as described in claim 1 further comprises a heat sink disposed on the magnetic core, wherein the heat sink contacts a top surface and a side surface of the magnetic core. A magnetic element as described in claim 14, wherein the heat sink is L-shaped, and the length of the portion of the heat sink contacting the side of the magnetic core is less than the height of the magnetic core. A magnetic element as described in claim 14, wherein the heat sink is attached to the magnetic core by a colloid having a Shore D or Shore A hardness less than 80. The magnetic element as described in claim 1, wherein the at least two coils include a primary coil and a secondary coil, and the at least one partition includes an annular structure disposed between the primary coil and the secondary coil.

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