Transformer, transformer unit, and method for manufacturing transformer

Abstract

A transformer, a transformer unit and a method for manufacturing a transformer, the transformer comprising a core (3, 4), a primary coil component (30) formed of a flat plate-shaped component and wound around the core (3, 4), and a secondary coil component (40) formed of a flat plate-shaped component and wound around the core (3, 4). A plurality of primary coil components (30) are electrically connected in series, a plurality of secondary coil components (40) are electrically connected in series, and at least a portion of the plurality of primary coil components (30) and at least a portion of the plurality of secondary coil components (40) are alternately overlapped and arranged with an insulating portion (17) therebetween.

Description

Technical Field

[0001] The present application relates to a transformer, a transformer unit and a method for manufacturing the transformer. Background Art

[0002] The transformer used in the insulation type power conversion device is driven at a high frequency of several tens of kHz to several hundreds of kHz. If the transformer is driven at a high frequency, the conduction loss caused by the AC resistance of the coil increases. Therefore, by using a flat conductor as the coil, the increase in conduction loss is suppressed and the heat dissipation of the coil is improved (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-207919 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] In conventional transformers, flat plate-shaped conductors formed in a spiral shape are used as coils and stacked together. This requires space for forming the conductor in a spiral shape, which increases the size of the transformer.

[0008] The present application is formed to solve the above-mentioned problems, and its purpose is to provide a small transformer with high heat dissipation.

[0009] Technical solutions adopted to solve technical problems

[0010] The transformer disclosed in the present application includes: an annular core; a plurality of primary coil components, each of which is composed of a flat plate-shaped component and is respectively wound around the core; a plurality of secondary coil components, each of which is composed of a flat plate-shaped component and is respectively wound around the core; a connecting portion, the connecting portion is used to electrically connect the plurality of primary coil components in series, the connecting portion connects primary coil terminals at both ends of the plurality of primary coil components connected in series, the connecting portion is used to electrically connect the plurality of secondary coil components in series, the connecting portion connects secondary coil terminals at both ends of the plurality of secondary coil components connected in series; and a resin portion, the resin portion covers the primary coil components and the secondary coil components, and at least a portion of the primary coil components and at least a portion of the secondary coil components are alternately overlapped and arranged with the resin portion interposed therebetween.

[0011] Effects of the Invention

[0012] In the transformer disclosed in the present application, a plurality of primary coil components composed of flat-plate-shaped components and respectively wound around a core body are electrically connected in series, a plurality of secondary coil components composed of flat-plate-shaped components and respectively wound around a core body are electrically connected in series, and at least a portion of the plurality of primary coil components and at least a portion of the plurality of secondary coil components are arranged alternately and overlappingly, thereby obtaining a small transformer with high heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view of the transformer according to the first embodiment.

[0014] Figure 2 This is a circuit diagram of a power conversion device equipped with the transformer of the first embodiment.

[0015] Figure 3 This is a perspective view of the coil component according to the first embodiment.

[0016] Figure 4 This is a process diagram of the method for manufacturing the transformer according to the first embodiment.

[0017] Figure 5 This is a perspective view of a coil structure formed by the coil structure forming step of the transformer manufacturing method according to the first embodiment.

[0018] Figure 6 This is a side view of the coil structure formed by the coil structure forming step of the transformer manufacturing method according to the first embodiment.

[0019] Figure 7 It is a perspective view of the primary coil member and the secondary coil member of the transformer according to the first embodiment.

[0020] Figure 8 It is a perspective view of the primary coil member and the secondary coil member of the transformer according to the first embodiment.

[0021] Fig. 9 This is a perspective view of a coil structure covered with a resin portion formed in the resin portion forming step of the transformer manufacturing method according to the first embodiment.

[0022] Fig.10 This is a cross-sectional view of the coil component according to the first embodiment.

[0023] Fig.11 This is a cross-sectional view of the coil component according to the first embodiment.

[0024] Fig.12 It is a cross-sectional view of the transformer according to the first embodiment.

[0025] Fig.13 It is a perspective view of a transformer according to the second embodiment.

[0026] Fig.14 It is a perspective view of a transformer according to the second embodiment.

[0027] Fig.15 It is a cross-sectional view of a transformer according to the second embodiment.

[0028] Fig.16 This is a process diagram of a method for manufacturing a transformer according to the second embodiment.

[0029] Fig.17 It is a perspective view of a transformer unit according to the third embodiment.

[0030] Fig.18 It is a cross-sectional view of a transformer unit according to the third embodiment.

[0031] Explanation of symbols

[0032] 1, 1a transformer; 2 coil component; 3, 4 core; 5 tape; 6 primary coil; 7 secondary coil; 8, 9 primary coil terminal; 10, 11 secondary coil terminal; 12 through hole; 13 connecting portion; 14 terminal member; 15 hole; 16 connecting portion; 17, 17a resin portion; 18 protrusion; 19 core bottom surface; 20 heat dissipation shell; 21 heat dissipation sealing resin; 22 recessed portion; 23 resin portion bottom surface; 30 primary coil member; 31, 32 primary coil member terminal; 40 secondary coil member; 41, 42 secondary coil member terminal; 100 coil axis; 161, 162 primary coil member connecting portion; 163, 164 secondary coil member connecting portion; 165, 166, 167 hole; 168 notch; 200 power conversion device; 201 primary circuit; 202 secondary circuit; 300 coil structure; 400 transformer unit. DETAILED DESCRIPTION

[0033] Hereinafter, the transformer for implementing the embodiment of the present application will be described in detail with reference to the accompanying drawings. In addition, in each figure, the same symbol represents the same or similar part.

[0034] Implementation Method 1

[0035] Figure 1 : is a three-dimensional diagram of a transformer 1 according to the first embodiment. The transformer 1 according to the first embodiment is composed of a coil component 2, a core 3, a core 4, and a tape 5. In the description of this application, the direction of the coil axis 100 of the transformer 1 is set as the y direction, and the two directions orthogonal to the y direction and to each other are set as the x direction and the z direction. The core 3 and the core 4 are made of a magnetic material such as ferrite. In addition, Figure 1In the figure, the core 4 is hidden by the coil component 2 and is not shown. The core 3 and the core 4 are mounted on the coil component 2, and the coil component 2, the core 3 and the core 4 are fixed by the tape 5. In addition, the coil 2, the core 3 and the core 4 may not be fixed by the tape, for example, they may be fixed by an adhesive or a leaf spring.

[0036] Figure 2 1 is a circuit diagram of a power conversion device equipped with the transformer 1 according to the first embodiment. Figure 2 The power conversion device 200 transmits power from the primary coil 6 of the primary circuit 201 on the low voltage side to the secondary coil 7 of the secondary circuit 202 on the high voltage side. The transformer 1 includes the primary coil 6 and the secondary coil 7. Figure 1 The primary coil terminals 8 and 9 of the transformer 1 are connected to the primary coil 6 , and the secondary coil terminals 10 and 11 are connected to the secondary coil 7 .

[0037] Figure 3 1 is a three-dimensional view of the coil component 2 of the first embodiment. The coil component 2 is composed of a coil structure 300 and a resin portion 17 covering the coil structure 300. The details of the coil structure 300 and the resin portion 17 will be described later. The coil component 2 is provided with a through hole 12 for inserting the core 3 and the core 4. The core 3 and the core 4 are U-shaped. Figure 3 Insert the core 4 into the through hole 12 in the positive direction of the y-axis. Figure 3 The U-shaped core 3 and the U-shaped core 4 are connected to each other in the through hole 12, and the integrated core 3 and core 4 are formed into a ring shape as a whole. The coil component 2, the core 3 and the core 4 are fixed by the tape 5, so as to form Figure 1 The transformer 1 is shown. In the first embodiment, the core 3 and the core 4 are respectively configured in a U shape, but one of the core 3 and the core 4 may be configured in a U shape and the other in an I shape. In addition, as long as the core that is finally integrated is configured in a ring shape as a whole, more than three cores may be integrated.

[0038] Next, a method for manufacturing the transformer according to the first embodiment will be described. Figure 4 1 is a process diagram of a method for manufacturing a transformer according to Embodiment 1. Next, the details of each process will be described, and the details of the internal structure of the transformer according to Embodiment 1 will be described.

[0039] Figure 5 It is a perspective view of the coil structure 300 formed in the coil structure forming step of step ST1 . Figure 6 is a side view of the coil structure 300, viewed from the positive direction of the x-axis Figure 5The coil structure 300 is composed of a terminal member 14, a primary coil member 30, a secondary coil member 40 and a connecting portion 16. The connecting portion 16 is, for example, a printed wiring board formed by pasting copper foil to glass epoxy resin. In the coil structure forming process of step ST1, the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 are connected by the connecting portion 13 to form the terminal member 14. The connecting portion 13 is removed in the connecting portion removal process of step ST3 described later, and the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 constitute independent terminals. Holes 15 are provided at both ends of the terminal member 14. The holes 15 are used in the resin portion forming process of step ST2 described later.

[0040] Figure 7 as well as Figure 8 1 is a perspective view of the primary coil member 30 and the secondary coil member 40 . The secondary coil member 40 has the same shape as the primary coil member 30 . Figure 8 The primary coil member 30 and the secondary coil member 40 are connected by Figure 7 The primary coil member 30 and the secondary coil member 40 are shown flipped in the xz plane which is perpendicular to the y direction, i.e., the direction of the coil axis 100 of the transformer 1. The primary coil member 30 and the secondary coil member 40 are arranged in Figure 1 The structure of the transformer 1 shown in the figure is wound around the core 3 or the core 4 for one cycle. Figure 7 as well as Figure 8 The primary coil component 30 and the secondary coil component 40 are structured as a relatively thin flat plate in the direction of the coil axis 100 of the transformer 1, i.e., the y direction. The primary coil component 30 and the secondary coil component 40 can be made of, for example, a conductor such as copper or aluminum, and a portion or the entire surface thereof is plated with tin or nickel. The primary coil component 30 has primary coil component terminals 31 and 32 at both ends of the conductor, and the primary coil components 31 and 32 are formed at a position biased to one side in an xz plane perpendicular to the direction of the coil axis 100, i.e., the y direction. The secondary coil component 40 includes secondary coil component terminals 41 and 42, and the secondary coil component terminals 41 and 42 are formed at the same position as the primary coil component terminals 31 and 32. By forming the primary coil component terminals 31 and 32 and the secondary coil component terminals 41 and 42 at the above-mentioned positions, when the primary coil component terminals 31 and 32 are formed ... Figure 7 The coil member shown is used as the primary coil member 30 and Figure 8 When the coil member shown is used as the secondary coil member 40 and is respectively arranged to overlap, the positions of the primary coil member terminals 31 and 32 are separated from the positions of the secondary coil member terminals 41 and 42. The primary coil member 30 and the secondary coil member 40 can be easily and inexpensively manufactured by punching a flat conductor with a punching machine.

[0041] The connection portion 16 includes a metal wiring pattern and a through hole. In the coil structure forming process of step ST1, the primary coil component terminals 31 and 32 of the primary coil component 30, the secondary coil component terminals 41 and 42 of the secondary coil component 40, the primary coil terminals 8 and 9, and the secondary coil terminals 10 and 11 are connected to the metal wiring pattern of the through hole of the connection portion 16, for example, by welding.

[0042] Next, the structure of the coil will be described. The primary coil 6 is composed of the primary coil member 30 and the metal wiring pattern of the connecting portion 16, and the secondary coil 7 is composed of the secondary coil member 40 and the metal wiring pattern of the connecting portion 16. The primary coil member 30 and the secondary coil member 40 are arranged to overlap alternately and spaced apart in the direction of the coil axis 100 of the transformer 1, that is, the y direction. Figure 5 as well as Figure 6 In the coil structure 300 shown, the primary coil member 30 and a part of the secondary coil member 40 are arranged at equal intervals.

[0043] In the primary coil 6, a plurality of primary coil members 30 are electrically connected in series via a metal wiring pattern of the connection portion 16. Figure 5 In the circuit, the primary coil terminal 8 and Figure 7 The primary coil member terminals 31 of the first primary coil member 30 are shown connected, and the primary coil member terminals 32 of the first primary coil member 30 are connected to the primary coil member terminals 31 of the second primary coil member 30 . Figure 7 The first to fourth primary coil members 30 are shown in FIG. Figure 5 The primary coil member terminal 32 of the fourth primary coil member 30 passes through the metal wiring pattern of the connecting portion 16 and is electrically connected in series at the primary coil member connecting portion 161 of the connecting portion 16. Figure 8 The primary coil member terminals 31 of the fifth primary coil member 30 are shown connected. Figure 8 The fifth primary coil member 30 to the eighth primary coil member 30 shown are Figure 5 The primary coil member connecting portion 162 of the connecting portion 16 is electrically connected in series. Finally, the primary coil member terminal 32 of the eighth primary coil member 30 is connected to the primary coil terminal 9. Thus, the primary coil 6 composed of the plurality of primary coil members 30 and the metal wiring pattern of the connecting portion 16 is configured to be connected in series. Figure 1 In the transformer 1 shown, the coil is wound around the core 3 and the core 4. The number of primary coil members 30 arranged constitutes the number of turns of the primary coil 6.

[0044] In the secondary coil 7, a plurality of secondary coil members 40 are electrically connected in series via a metal wiring pattern of the connection portion 16. Figure 5 In the secondary coil terminal 10 and Figure 8 The first secondary coil member 40 shown is connected, at the secondary coil member connection portion 163, Figure 8 The first to sixth secondary coil members 40 are connected in series, and at the secondary coil member connection portion 164, Figure 7 The seventh to twelfth secondary coil members 40 are electrically connected in series, and the twelfth secondary coil member 40 is connected to the secondary coil terminal 11. Thus, the secondary coil 7 composed of the plurality of secondary coil members 40 and the metal wiring pattern of the connecting portion 16 is configured to be connected in series. Figure 1 In the transformer 1 shown, the coil is wound around the core 3 and the core 4. The number of the arranged secondary coil members 40 defines the number of turns of the secondary coil 7.

[0045] In this way, by using the coil member having the coil member terminal formed at a position biased to one side in the planar direction in a reversed manner in the primary coil member 30 and the secondary coil member 40, the distance between the primary coil terminal 80 connected to the primary coil member 30 and the secondary coil terminal 10 connected to the secondary coil member 40 can be increased, and the distance between the primary coil terminal 9 connected to the primary coil member 30 and the secondary coil terminal 11 connected to the secondary coil member 40 can be increased, thereby ensuring the insulation distance even in a smaller coil structure 300. In addition, the secondary coil member 40 adopts the same shape as the primary coil member 30, but it does not matter if it is a different shape as long as it can ensure the insulation distance.

[0046] When the primary coil components 30 and the secondary coil components 40 are arranged to overlap, the primary coil components 30 and the secondary coil components 40, whichever is larger in number, in other words, the coil component with a larger number of turns of the coil, are arranged so that the coil component terminals thereof become the outside of the connection portion 16. That is, the primary coil components 30 and the secondary coil components 40, compared with the primary coil components 30 and the secondary coil components 40, are connected to the connection portion 16 on the outside of the connection portion 16. In the coil structure 300 of the first embodiment, since the number of the secondary coil components 40 is larger than the number of the primary coil components 30, the secondary coil component terminals 41 and the secondary coil component terminals 42 of the secondary coil components 40 are arranged to be closer to the outside of the connection portion 16 than the primary coil component terminals 31 and the primary coil component terminals 32 of the primary coil components 30. By the above arrangement, the insulation distance between the secondary coil terminals 10 and the secondary coil terminals 11 connected to the secondary coil 7 on the high voltage side can be increased. In other words, the insulation distance between the terminals on the high voltage side can be ensured, and the transformer 1 can be miniaturized.

[0047] In addition, regarding the flat plate-shaped primary coil member 30 and the secondary coil member 40, at least a portion of the primary coil member 30 and at least a portion of the secondary coil member 40 are arranged to overlap alternately, thereby causing the magnetic flux generated by the primary coil member 30 and the magnetic flux generated by the secondary coil member 40 to cancel each other out, resulting in reduced leakage magnetic flux. In addition, since the flat plate-shaped primary coil member 30 and the secondary coil member 40 wound around the core bodies 3 and 4 are arranged to overlap, compared to the case where the flat plate-shaped coil member formed into a spiral shape is arranged to overlap, it is possible to overlap the primary coil member 30 and the secondary coil member 40 in a plane perpendicular to the coil axis 100. Figure 5 The size of transformer 1 is reduced in the xz plane.

[0048] If the transformer is driven at a high frequency, the current moves to a position closer to the surface of the coil due to the skin effect, the effective cross-sectional area of ​​the coil is reduced, and the power loss increases. However, in the transformer 1 of the first embodiment, since the planes of the primary coil member 30 and the secondary coil member 40 with larger effective cross-sectional areas are arranged to overlap each other, the increase in power loss can be suppressed. As a result, since the heat generation of the transformer 1 can be suppressed, the structure required for cooling can be made smaller, and the transformer 1 can be miniaturized.

[0049] When the primary coil member 30 and the secondary coil member 40 are arranged to overlap, the primary coil member 30 and the secondary coil member 40, whichever has a larger number of coil turns, are arranged at both ends of the overlapping arrangement. Figure 6 In the coil structure 300 shown, when the primary coil member 30 and the secondary coil member 40 are arranged overlapping, the secondary coil members 40 are arranged at both ends. By arranging as described above, the effect of suppressing power loss of the coil member can be obtained with a smaller volume, and the transformer 1 can be miniaturized.

[0050] In addition, Figure 5In the coil structure 300 shown, the primary coil 6 is set to the low voltage side, the secondary coil 7 is set to the high voltage side, and the number of secondary coil components 40 is greater than the number of secondary coil components 30. However, in the case of stepping down the voltage by the transformer 1, the number of secondary coil components 40 is less than the number of primary coil components 30. As for the primary coil components 30 and the secondary coil components 40, it is sufficient to determine their respective numbers as needed. In addition, the number of primary coil components 30 connected at the primary coil component connection portion 161 and the number of primary coil components 30 connected at the primary coil component connection portion 162 are set to be the same, and the number of secondary coil components 40 connected at the secondary coil component connection portion 163 and the number of secondary coil components 40 connected at the secondary coil component connection portion 164 are set to be the same. However, as long as the respective coil components are connected in series, different numbers of coil components can also be arranged in an overlapping manner.

[0051] The primary coil members 30 and the secondary coil members 40 are alternately arranged to overlap each other. However, when the number of primary coil members 30 is different from the number of secondary coil members 40, a larger number of coil members may be continuously arranged at the ends of the overlapping arrangement.

[0052] The connection portion 16 is provided with holes 165, 166, 167 and a notch 168. The hole 165 and the notch 168 are used for positioning when performing welding connection. Thus, the welding connection can be performed with high precision. As a result, the deviation of the heat generation of the coil caused by the deviation of the welding connection can be suppressed, and the structure required for cooling can be set to the required minimum. The two holes 166 are used to adjust the flow of the resin in the resin portion forming process of step ST2 described later, thereby, the resin portion 17 can be stably formed. In addition, by using the two holes 167, the insulation distance between the primary coil component connection portion 161 and the secondary coil component connection portion 163 can be ensured, and the insulation distance between the primary coil component connection portion 162 and the secondary coil component connection portion 164 can be ensured. Therefore, by providing the hole 167, the connection portion 16 can be set smaller than in the case where there is no hole 167.

[0053] In the first embodiment, a printed wiring board is used for the connection portion 16, but a metal member may be used to connect the terminals. In addition, the terminals may be directly welded or bonded together.

[0054] In the resin portion forming step of step ST2 , a part of the coil structure 300 formed in the coil structure forming step of step ST1 is covered with resin, thereby forming the resin portion 17 . Fig. 91 is a perspective view showing a coil structure 300 covered by a resin portion 17 formed in the resin portion forming process of step ST2. The resin portion 17 is, for example, made of a thermosetting resin, i.e., epoxy resin, and is formed by covering the coil structure 300 by transfer molding or insert molding. By forming the resin portion 17 as described above, the required minimum insulation distance can be ensured between the primary coil component 30 and the secondary coil component 40. In addition, when the resin portion 17 is formed by transfer molding using a thermosetting resin, i.e., epoxy resin, the resin fluidity of the thermosetting resin is better than that of the thermoplastic resin, and therefore, the thickness of the resin can be set thinner than when it is formed by a thermoplastic resin. As a result, the transformer 1 can be miniaturized. In addition, the resin portion 17 can also be formed by insert molding using a thermoplastic resin having high thermal conductivity.

[0055] The resin portion 17 is formed in a manner that the coil structure 300 is used as an insert and covers the surrounding thereof, a portion of the terminal member 14, namely, a portion of the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 is exposed, and a protrusion 18 is provided on the outer periphery. The protrusion 18 is used for positioning when setting a cooler, etc. Thus, since the cooler, etc. can be set with high precision, heat can be efficiently dissipated through the cooler. In addition, a through hole 12 is provided at a position where the core body 3 and the core body 4 are inserted, namely, a position where the primary coil member 30 and the secondary coil member 40 are rolled in. The resin portion 17 is formed to cover the primary coil member terminals 31, 32 and the secondary coil member terminals 41, 42 on the upper surface portion of the connecting portion 16, and is formed to expose a portion of the connecting portion 16 on other portions of the connecting portion 16. The resin portion 17 is formed to expose a portion of the connecting portion 16 on the lower surface portion of the connecting portion 16 in the same manner as the upper surface portion. By the above configuration, the insulation of the part requiring insulation can be ensured, and the part not requiring insulation does not use resin, which can reduce the amount of resin used. In addition, by using the area of ​​a part of the exposed connection portion 16 as the contact surface of the mold during transfer molding, transfer molding can be stably performed.

[0056] Fig.10 Yes means Fig. 9 Cross-sectional view of section AA in FIG. Fig.11 Yes means Fig. 9 The sectional view of the BB section in. Fig.11 In the embodiment, the coil axis 100 passes through the through hole 12 along the depth direction, i.e., the y direction. Fig.10 As shown, regarding the bottom surface of the primary coil member 30 and the secondary coil member 40, that is, the end portion in the negative direction of the z-axis, the thickness T of the resin portion 17 covering this portion is thinner than the thickness of other portions. Fig.11As shown, the thickness T of the resin portion 17 covering the side surfaces of the primary coil member 30 and the secondary coil member 40, i.e., the two ends of the x-axis, is thinner than the thickness of other portions. By forming the resin portion 17 as described above, the resin flow during transfer molding or insert molding can be ensured, and the thermal resistance can be reduced by reducing the thickness of only the portion that has the greatest influence on heat dissipation, so that heat can be efficiently dissipated and the transformer 1 can be made smaller.

[0057] The holes 15 provided at both ends of the terminal member 14 are used for positioning with the molding die when the resin portion 17 is formed by transfer molding. Thus, the resin portion 17 can be formed with high precision. In addition, by providing the connecting portion 13, it is possible to suppress the resin from flowing toward the front end direction of the primary coil terminals 8, 9 and the secondary coil terminals 10, 11, thereby suppressing the burrs generated by the resin.

[0058] In the connecting portion removal process of step ST3, Fig. 9 The coil structure 300 covered with the resin portion 17 shown in the figure is cut off from the connecting portion 13, and the front ends of the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 are bent. Figure 3 The coil component 2 is shown.

[0059] In the core inserting process of step ST4, the core 3 and the core 4 are inserted into the through hole 12 of the coil component 2, and the coil component 2, the core 3 and the core 4 are fixed by the tape 5, thereby obtaining Figure 1 The transformer 1 is shown.

[0060] Fig.12 is a cross-sectional view of the transformer 1 obtained through the core insertion process of step ST4, showing Figure 1 The CC section in Fig. 9 Compared with the coil structure 300 covered with the resin portion 17 formed in the resin portion forming step of step ST2, Fig.12 In the process, the front end of the secondary coil terminal 11 is bent, the core 3 and the core 4 are inserted into the through hole 12 of the coil component 2, and the coil component 2, the core 3 and the core 4 are fixed by the tape 5.

[0061] In addition, in the coil structure forming process of the first embodiment, the terminal member 14 in which the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 are connected by the connecting portion 13 is used, but the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 without the connecting portion 13 may also be used. In this case, it is not necessary to remove the connecting portion 13 in the connecting portion removing process of step ST3. In addition, the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 are set to a structure with the front end bent, but they can also be set to a straight structure without bending, or they can also be set to a structure bent multiple times. In addition, threaded holes can also be set at the front ends of the primary coil terminals 8, 9 and the secondary coil terminals 10, 11.

[0062] As described above, in the transformer 1 of the first embodiment, the flat primary coil components 30 and the secondary coil components 40 wound around the core 3 or the core 4 are alternately overlapped, the primary coil components 30 are connected in series to form the primary coil 6, and the secondary coil components are connected in series to form the secondary coil 7. Therefore, the transformer 1 can have high heat dissipation and the size of the transformer 1 can be set smaller.

[0063] Implementation Method 2

[0064] Fig.13 as well as Fig.14 is a perspective view of a transformer 1a according to a second embodiment. Fig.14 Observed from the negative direction of the z-axis Fig.13 The transformer 1a is shown. Fig.15 Yes means Fig.13 Cross-sectional view of the DD section in. Fig.13 , Fig.14 as well as Fig.15 The transformer 1 a in the embodiment is different from the transformer 1 in the embodiment 1 in that the resin portion 17 a covers the core 3 and the core 4 .

[0065] Next, a method for manufacturing the transformer 1 a according to the second embodiment will be described. Fig.16 1 is a process diagram of a method for manufacturing a transformer 1a according to Embodiment 2. The coil structure forming process of the first step ST1 is the same as step ST1 in the manufacturing method according to Embodiment 1. In the next step ST4a, the core inserting process, the core 3 and the core 4 are inserted into the portion corresponding to the through hole 12 of the core structure 300 formed in step ST1.

[0066] In the resin portion forming process of step ST2a, the coil structure 300 equipped with the core 3 and the core 4 formed in the core inserting process of step ST4a is covered with resin, thereby forming the resin portion 17a. At this time, the upper part and the side surface of the core 3 and the core 4 are covered with resin, but at least a part of the bottom surface of the core 3 and the core 4, that is, the core bottom surface 19 is not covered with resin and is exposed.

[0067] In the connecting portion removing step of step ST3, the connecting portion 13 is cut off from the primary coil terminals 8, 9 and the secondary coil terminals 10, 11, and the front ends of the primary coil terminals 8, 9 and the secondary coil terminals 10, 11 are bent with respect to the coil structure 300 into which the cores 3 and 4 obtained in the resin portion forming step of step ST2a and covered with the resin portion 17a are inserted. Fig.13 , Fig.14 as well as Fig.15 The transformer 1a is shown.

[0068] In this way, the coil structure 300 with the core 3 and the core 4 inserted therein is covered with resin to form the resin portion 17a. In addition to being able to obtain the effect obtained by the transformer 1 of the first embodiment, it is also unnecessary to have components such as the tape 5, which can reduce the assembly cost, thereby reducing the manufacturing cost of the transformer 1a. In addition, since there is no gap between the core 3 and the core 4 and the coil structure 300, the heat dissipation will be improved.

[0069] Implementation Method 3

[0070] Fig.17 is a perspective view of a transformer unit 400 according to a third embodiment. Fig.18 Yes means Fig.17 The transformer unit 400 is composed of Figure 1 The transformer 1 shown is composed of a heat dissipation housing 20 and a heat dissipation sealing resin 21. The heat dissipation housing 20 is integrated with a cooler (not shown) or releases the heat of the transformer 1 to the cooler, and the heat dissipation housing 20 is made of aluminum, for example. The bottom surfaces of the core 3 and the core 4, i.e., the core bottom surface 19, are in contact with the heat dissipation housing 20. A recessed portion 22 is provided at the bottom of the interior of the heat dissipation housing 20, and the bottom surface of the coil component 2, i.e., the bottom surface of the resin portion 17, i.e., the resin portion bottom surface 23, is separated from the heat dissipation housing 20 at the recessed portion 22. By setting the above structure, the heat generated by the primary coil component 30 and the secondary coil component 40 can be released to the heat dissipation housing 20 via the cores 3 and 4, so that the transformer 1 can be efficiently cooled.

[0071] In addition, the space between the transformer 1 and the heat dissipation housing 20 is filled with a heat dissipation sealing resin 21, and the transformer 1 is fixed to the heat dissipation housing 20 by the heat dissipation sealing resin 21. In addition, the heat from the transformer 1 can be released to the heat dissipation housing 20 via the heat dissipation sealing resin 21, so that the transformer 1 can be efficiently cooled. In addition, since the primary coil component 30 and the secondary coil component 40 are covered by the resin portion 17 as a whole, the insulation between them and the housing can be ensured, and the coil component 2 does not need to be covered as a whole by the heat dissipation sealing resin 21. Therefore, the upper part of the coil component 21 is not covered by the heat dissipation sealing resin 21, the use amount of the heat dissipation sealing resin 21 can be reduced, and the upper space of the coil component 2 can be used for other purposes.

[0072] The present application describes various exemplary embodiments, but various features, methods, and functions described in one or more embodiments are not limited to application to specific embodiments and can be applied to the embodiments alone or in various combinations.

[0073] Therefore, numerous modifications not shown are contemplated within the technical scope disclosed in this application, including, for example, modifications, additions, or omissions of at least one component, and also including extraction of at least one component and combination with components of other embodiments.

Claims

1. A transformer, characterized in that: include: Ring-shaped core; a plurality of primary coil members, each of which is formed of a flat plate-shaped member and is wound around the core body once; A plurality of secondary coil members, each of which is formed of a flat plate-shaped member and is wound around the core body once; A connecting portion, wherein the plurality of primary coil components are electrically connected in series, and the connecting portion connects primary coil terminals at both ends of the plurality of primary coil components connected in series; and the connecting portion, wherein the plurality of secondary coil components are electrically connected in series, and the connecting portion connects secondary coil terminals at both ends of the plurality of secondary coil components connected in series; as well as a resin portion covering the primary coil member and the secondary coil member, At least a portion of the primary coil members and at least a portion of the secondary coil members are alternately arranged to overlap with each other via a resin portion. If the direction of the coil axis is set to the y direction, the connection direction of the primary coil terminal and the secondary coil terminal orthogonal to the y direction is set to the z direction, and the direction orthogonal to the y direction and the z direction is set to the x direction, then the thickness of the resin part covering the bottom and side surfaces of the primary coil component and the secondary coil component is thinner than the thickness of other parts, wherein the bottom surfaces of the primary coil component and the secondary coil component are the ends on the opposite side of the primary coil terminal and the secondary coil terminal in the z direction, and the side surfaces are the two ends in the x direction.

2. The transformer according to claim 1, characterized in that A portion of the primary coil terminal and a portion of the secondary coil terminal are exposed from the resin portion.

3. The transformer according to claim 1 or 2, characterized in that: The primary coil member and at least a portion of the secondary coil member are arranged at equal intervals. If the direction of the coil axis is set to the y direction, the connection direction of the primary coil terminal and the secondary coil terminal orthogonal to the y direction is set to the z direction, and the direction orthogonal to the y direction and the z direction is set to the x direction, then compared with the smaller one of the primary coil component and the secondary coil component, the larger one of the primary coil component and the secondary coil component is connected to the connecting portion on the outer side of the x direction of the connecting portion.

4. The transformer according to claim 1 or 2, characterized in that: The primary coil member includes primary coil member terminals formed at both ends of the conductor at positions deviated to one side in a plane direction perpendicular to the coil axis. The secondary coil member includes secondary coil member terminals formed at both ends of the conductor at positions deviated to one side in a plane direction perpendicular to the coil axis. When the primary coil member and the secondary coil member are arranged to overlap, the primary coil member terminal and the secondary coil member terminal are arranged at separate positions.

5. The transformer according to claim 1 or 2, characterized in that: The primary coil members or the secondary coil members, whichever has a larger number, are arranged at both ends of the overlapping arrangement body.

6. The transformer according to claim 1 or 2, characterized in that: A portion of the connection portion is exposed from the resin portion.

7. The transformer according to claim 1 or 2, characterized in that: The connection portion has a hole between a primary coil member connection portion that electrically connects the primary coil members in series and a secondary coil member connection portion that electrically connects the secondary coil members in series.

8. The transformer according to claim 1 or 2, characterized in that: The connection portion is a printed wiring board to which copper foil is attached.

9. The transformer according to claim 1 or 2, characterized in that: The resin portion has a protrusion on an outer periphery.

10. The transformer according to claim 1 or 2, characterized in that: The resin portion is a thermosetting resin.

11. The transformer according to claim 1 or 2, characterized in that: A portion of the core is covered with the resin portion.

12. A transformer unit, characterized in that: include: The transformer according to any one of claims 1 to 11; as well as a heat dissipation housing, wherein the heat dissipation housing releases heat from the transformer, A portion of the bottom surface of the core body that is not covered by the resin portion is in contact with the heat dissipation housing. A recessed portion is provided at the bottom of the interior of the heat dissipation housing, and a bottom surface of the resin portion is separated from the heat dissipation housing at the recessed portion.

13. The transformer unit according to claim 12, characterized in that A heat dissipation sealing resin is filled between the transformer and the heat dissipation housing.

14. A method for manufacturing a transformer, characterized in that: The manufacturing method includes a coil structure forming step, a resin portion forming step, and a core inserting step. In the coil structure forming step, A plurality of primary coil members each consisting of a flat plate-shaped member and wound around a core body are electrically connected in series. A plurality of secondary coil members, each of which is formed of a flat plate-shaped member and is wound around the core body once, are electrically connected in series. At least a part of the primary coil members among the plurality of primary coil members and at least a part of the secondary coil members among the plurality of secondary coil members are spaced apart and alternately overlapped with each other, connecting both ends of the plurality of primary coil members electrically connected in series to primary coil terminals, The two ends of the plurality of secondary coil members electrically connected in series are connected together with the secondary coil terminals, thereby forming a coil structure. In the resin portion forming process, a through hole is provided at a position where the primary coil component and the secondary coil component are wound, and the primary coil component and the secondary coil component are covered with resin to form a resin portion. If the direction of the coil axis is set to the y direction, the connection direction of the primary coil terminal and the secondary coil terminal orthogonal to the y direction is set to the z direction, and the direction orthogonal to the y direction and the z direction is set to the x direction, then the thickness of the resin portion covering the bottom surface and the side surface of the primary coil component and the secondary coil component is thinner than the thickness of other parts, wherein the bottom surface of the primary coil component and the secondary coil component is the end on the opposite side of the primary coil terminal and the secondary coil terminal in the z direction, and the side surface is the two end portions in the x direction. In the core body inserting step, the core body is inserted into the through hole.

15. A method for manufacturing a transformer, characterized in that: The manufacturing method includes a coil structure forming step, a resin portion forming step, a connecting portion removing step, and a core inserting step. In the coil structure forming step, A plurality of primary coil members each consisting of a flat plate-shaped member and wound around a core body are electrically connected in series. A plurality of secondary coil members, each of which is formed of a flat plate-shaped member and is wound around the core body once, are electrically connected in series. At least a part of the primary coil members among the plurality of primary coil members and at least a part of the secondary coil members among the plurality of secondary coil members are spaced apart and alternately overlapped with each other, connecting both ends of the plurality of primary coil members electrically connected in series to the primary coil terminals of a terminal member formed by connecting a primary coil terminal and a secondary coil terminal via a connecting portion, The coil structure is formed by connecting both ends of the plurality of secondary coil members electrically connected in series to the secondary coil terminals of the terminal member. In the resin portion forming process, a through hole is provided at a position where the primary coil component and the secondary coil component are wound, and the primary coil component and the secondary coil component are covered with resin to form a resin portion. If the direction of the coil axis is set to the y direction, the connection direction of the primary coil terminal and the secondary coil terminal orthogonal to the y direction is set to the z direction, and the direction orthogonal to the y direction and the z direction is set to the x direction, then the thickness of the resin portion covering the bottom surface and the side surface of the primary coil component and the secondary coil component is thinner than the thickness of other parts, wherein the bottom surface of the primary coil component and the secondary coil component is the end on the opposite side of the primary coil terminal and the secondary coil terminal in the z direction, and the side surface is the two end portions in the x direction. In the connecting portion removing step, the connecting portion is removed. In the core body inserting step, the core body is inserted into the through hole.

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