Coil device

Abstract

To provide a coil device which can be reduced in size while ensuring leakage.SOLUTION: Provided is a coil device 1 including: a bobbin 10; a first wire 70 having a first coil 74 that is wound on the bobbin 10; a second wire 80 having a second coil 84 that is wound on the bobbin 10; and cores 60a, 60b attached to the bobbin 10. Main middle legs 64a, 64b of the respective cores 60a,60b are arranged inside the first coil 74 and the second coil 84, respectively. First sub middle legs 66a1, 66b1 of the respective cores 60a, 60b are arranged outside the second coil 84 and inside the first coil 74. Second sub middle legs 66a2, 66b2 of the respective cores 60a, 60b are arranged inside the second coil 84 and outside the first coil 74.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a coil device preferably used as a leakage transformer, for example.

Background Art

[0002] A leakage transformer is used as a composite transformer having the function of a choke coil in addition to the function of a transformer. In a leakage transformer, since the leakage serves as the function of a choke coil, the structure of the choke coil can be omitted, which contributes to downsizing of the transformer.

[0003] Patent Document 1 discloses a horizontal leakage transformer in which a secondary coil is arranged inside a primary coil, and a vertical leakage transformer in which the primary coil and the secondary coil are wound coaxially and arranged vertically.

[0004] However, in any transformer, a certain distance must be provided between the primary coil and the secondary coil in order to ensure leakage, and it is difficult to reduce the size of the transformer.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In view of such a situation, the present invention has been made, and an object thereof is to provide a coil device capable of ensuring leakage and reducing the size.

Means for Solving the Problems

[0007] To achieve the above object, the coil device according to the present invention is a bobbin, and A first wire having a first coil portion wound around the bobbin, A second wire having a second coil portion wound around the bobbin, A coil device having a core attached to the bobbin, The aforementioned core is A base portion extending in the first axial direction, The main central leg portion is positioned approximately in the center of the base portion in the first axial direction, In the base portion, a first sub-center leg portion is positioned on one side in the first axial direction relative to the main center leg portion, The base portion has a second sub-center leg portion located on the other side in the first axial direction, and the main center leg portion is located inside the first coil portion and the second coil portion. The first sub-center leg portion is positioned inside the first coil portion and outside the second coil portion. The second sub-center leg portion is positioned inside the second coil portion and outside the first coil portion.

[0008] This configuration allows leakage flux to be generated through the secondary central leg even when the coils are in close proximity, ensuring leakage and enabling miniaturization of the coil device. Furthermore, this configuration suppresses AC resistance and reduces the increase in copper loss.

[0009] Furthermore, this configuration makes it easy to adjust the turns ratio of the primary and secondary coils. For example, in conventional horizontal leakage transformers, it was difficult to ensure sufficient leakage while maintaining a compact size when the turns ratio of each coil was set to 1:1 and the inductances were matched. However, with the above configuration, even when the turns ratio of each coil is set to 1:1 and the inductances of each coil are matched, leakage can be easily ensured.

[0010] Preferably, the core has a first outer leg and a second outer leg positioned on the base portion, the first sub-intermediate leg positioned between the first outer leg and the main intermediate leg, the second sub-intermediate leg positioned between the second outer leg and the main intermediate leg, the first outer leg positioned outside the first coil portion, and the second outer leg positioned outside the second coil portion. With this configuration, each coil portion fits between the outer legs, enabling miniaturization of the coil device.

[0011] Preferably, the core has a first core portion which includes at least a first base portion which is part of the base portion, and a second core portion which includes at least a second base portion which is another part of the base portion and is substantially parallel to the first base portion, with the first core portion and the second core portion sandwiching the first coil portion and the second coil portion along the winding axis of the first coil portion. With this configuration, each coil fits between the base portions, making it possible to miniaturize the coil device.

[0012] Preferably, the bobbin has a first winding section around which the first coil section is wound, a second winding section around which the second coil section is wound, and a winding partition flange separating the first winding section and the second winding section. The first winding section has a first main through hole where the main middle leg is located and a first sub through hole where the first sub middle leg is located. The second winding section has a second main through hole where the main middle leg is located and a second sub through hole where the second sub middle leg is located, and the first main through hole and the second main through hole are in communication. With this configuration, the first wire and the second wire can be insulated, and each wire can be reliably insulated from the core.

[0013] Preferably, the cross-sectional area of ​​the main central leg is approximately the same as the sum of the cross-sectional areas of the first outer leg and the second outer leg. More preferably, the cross-sectional area of ​​the main central leg is larger than the cross-sectional area of ​​the first secondary central leg.

[0014] Preferably, the core is symmetric with respect to a symmetry axis orthogonal to the first axial direction. By configuring it in this way, it is easy to set the turn ratio between the first coil part and the second coil part to 1:1 and to make the inductances of the respective coils uniform.

[0015] Note that a first gap may be formed in the first sub-middle leg portion. The leakage can be adjusted by the first gap. Also, a second gap may be formed in the main middle leg portion, and preferably, the distance of the first gap is longer than the distance of the second gap. These gaps can prevent cracking of the leg portions.

[0016] Preferably, the first core portion and the second core portion are symmetric along the winding axis of the first coil part. Note that the core may be divided along the first axis and a second axis perpendicular to the winding axis of the first coil part.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a schematic perspective view showing the configuration of a coil device according to an embodiment of the present invention. [Figure 2A] FIG. 2A is a schematic view of a part of the coil device according to FIG. 1 as viewed from a different angle. [Figure 2B] FIG. 2B is a schematic view of a part of the coil device according to FIG. 1 as viewed from yet another different angle. [Figure 2C] FIG. 2C is a cross-sectional view taken along the IIC-IIC line shown in FIG. 2A. [Figure 3] FIG. 3 is a plan view showing the configuration of a part of the coil device according to FIG. 1. [Figure 4A] FIG. 4A is a schematic perspective view showing the configuration of the bobbin of the coil device according to FIG. 1. [Figure 4B] FIG. 4B is a plan view showing the configuration of the bobbin according to FIG. 4A. [Figure 4C] FIG. 4C is a rear view showing the configuration of the bobbin according to FIG. 4A. [Figure 4D]FIG. 4D is a cross-sectional view of the bobbin according to FIG. 4A taken along the IVD-IVD line. [Figure 4E] FIG. 4E is a cross-sectional view of the bobbin according to FIG. 4A taken along the IVE-IVE line. [Figure 5A] FIG. 5A is an exploded perspective view showing the configuration of the core of the coil device according to FIG. 1. [Figure 5B] FIG. 5B is a front view showing the configuration of the core of the coil device according to FIG. 1. [Figure 6] FIG. 6 is a schematic perspective view showing the configuration of the wire of the coil device according to FIG. 1. [Figure 7] FIG. 7 is a schematic perspective view showing the configuration of the case of the coil device according to FIG. 1.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0019] As shown in FIG. 1, the transformer 1 as the coil device according to the present embodiment is used, for example, as a leakage transformer, and is used in an in-vehicle charger for an electric vehicle, a general-purpose power supply, and the like.

[0020] As shown in FIG. 1, the transformer 1 has a first wire 70 and a second wire 80, a bobbin 10 around which the wire is wound, cores 60a and 60b that sandwich the bobbin 10 along the Z axis, and a case 90 that houses these inside. In the drawings, the X axis, the Y axis, and the Z axis are perpendicular to each other, and the Z axis corresponds to the height (thickness) of the transformer 1. In the present embodiment, the lower side in the Z-axis direction of the transformer 1 is the installation surface of the transformer 1. Further, the X axis coincides with the direction in which the base portion 62b of the core 60b extends. Furthermore, the Y axis is made to coincide with the direction in which the divided cores 61b and 61b of the core 60b are arranged.

[0021] Furthermore, in the specification, the direction in which core 60b is positioned may be described as "upward," and the direction in which core 60a is positioned may be described as "downward." Also, in the specification, the side closer to the center of transformer 1 may be described as "inside," and the side further from the center may be described as "outside."

[0022] In this embodiment, as shown in Figure 7, the case 90 is formed from a plate-shaped member, with the upper part in the Z-axis direction open and a bottom plate 92 formed on the lower part in the Z-axis direction. Fixing parts 91 are formed at the four corners of the bottom plate 92. The case 90 is preferably made of a metal such as aluminum copper or iron that has excellent heat dissipation properties, but it may also be made of PPS, PET, PBT, etc. Since the lower end surface in the Z-axis direction of the core 60a, which will be described later, comes into contact with the bottom plate 92, it is preferable that the bottom plate 92 be made of a material with excellent heat dissipation properties. Cooling devices such as cooling pipes and cooling fins may be attached to the bottom of the case 90 via the bottom plate 92 or directly.

[0023] The inside of case 90 may be filled with a heat-dissipating resin. The heat-dissipating resin is not particularly limited, but a resin with excellent heat dissipation properties, such as a thermal conductivity of 0.5 to 5, preferably 1 to 3 W / m·K, is preferred. Examples of resins with excellent heat dissipation properties include silicone resins, urethane resins, and epoxy resins.

[0024] Furthermore, it is preferable that the heat dissipation resin in this embodiment absorbs deformation even if the cores 60a, 60b or the bobbin 10 deform due to heat, and does not generate excessive stress on the cores 60a, 60b. Potting resin is an example of such a resin.

[0025] As shown in Figure 1, in this embodiment, core 60a has a base portion 62a which is the first core portion shown in Figure 5A. The base portion 62a is positioned below the bobbin 10 in the Z-axis direction. Core 60b has a base portion 62b which is the second core portion. The base portion 62b is positioned above the bobbin 10 in the Z-axis direction. In this embodiment, the material of each core 60a, 60b can be a metal, a soft magnetic material such as ferrite, etc., but is not particularly limited.

[0026] Cores 60a and 60b are symmetrical along the Z-axis. As shown in Figure 5A, core 60a can be separated into two identical divided cores 61a, 61a at a dividing surface 611a. Core 60b can be separated into two identical divided cores 61b, 61b at a dividing surface 611b. In this embodiment, each divided core 61a, 61a and 61b, 61b are all identical in shape.

[0027] The following describes the divided core 61a, and unless otherwise specified, the description of the divided core 61b will be omitted. The divided core 61a is symmetric with respect to the axis of symmetry (Z axis) perpendicular to the X axis.

[0028] As shown in Figure 5A, the base portion 62a of the divided core 61a extends along the X-axis. Outward from the center of the base portion 62a in the Y-axis direction, inclined surfaces 63a1, 63a1 are formed toward the center of the X-axis.

[0029] The base portion 62a has a main central leg portion 64a that protrudes upward in the Z-axis direction. The main central leg portion 64a is positioned approximately in the center of the base portion 62a in the X-axis direction.

[0030] Furthermore, the base portion 62a has a first outer leg portion 68a1 and a second outer leg portion 68a2 that project upward in the Z-axis direction. The first outer leg portion 68a1 is located at one end of the base portion 62a in the X-axis direction, and the second outer leg portion 68a2 is located at the other end of the base portion 62a in the X-axis direction.

[0031] Furthermore, the base portion 62a has a first sub-intermediate leg portion 66a1 and a second sub-intermediate leg portion 66a2 that project upward in the Z-axis direction. The first sub-intermediate leg portion 66a1 is positioned between the first outer leg portion 68a1 and the main intermediate leg portion 64a. The second sub-intermediate leg portion 66a2 is positioned between the second outer leg portion 68a2 and the main intermediate leg portion 64a.

[0032] As shown in Figure 1, the split core 61a is positioned below the bobbin 10 in the Z-axis direction, and the split core 61b is positioned below the bobbin 10 in the Z-axis direction. As shown in Figure 5B, the end faces 69a1 and 69b1 of the first outer legs 68a1 and 68b1 are abutted along the Z-axis, and the end faces 69a2 and 69b2 of the second outer legs 68a2 and 68b2 are abutted along the Z-axis.

[0033] As shown in Figure 5B, a gap 100a (first gap) of distance T1 is formed between the end face 67a1 of the first sub-mid leg portion 66a1 along the Z axis and the end face 67b1 of the first sub-mid leg portion 66b1 along the Z axis. A gap 100b (first gap) of distance T1 is formed between the end face 67a2 of the second sub-mid leg portion 66a2 along the Z axis and the end face 67b2 of the second sub-mid leg portion 66b2 along the Z axis.

[0034] A gap 101 (second gap) of distance T2 is formed between the end face 65a of the main central leg portion 64a along the Z axis and the end face 65b of the main central leg portion 64b along the Z axis. As shown in Figure 5B, T1 is configured to be longer than T2.

[0035] In this embodiment, the cross-sectional area S1 of the main central leg portion 64a shown in Figure 3 along the Z-axis is configured to be larger than the cross-sectional area S2 of the first sub-central leg portion 66a1 and the second sub-central leg portion 66a2 along the Z-axis. Furthermore, the cross-sectional area S1 of the main central leg portion 64a along the Z-axis is approximately the same as the sum of the cross-sectional areas S3 of the first outer leg portion 68a1 and the second outer leg portion 68a2 along the Z-axis.

[0036] As shown in Figure 4C, the bobbin 10 has a first end partition flange 30, a second end partition flange 32, and a winding partition flange 34. A first winding section 40, which forms the body of the bobbin, is formed between the first end partition flange 30 and the winding partition flange 34. A second winding section 50, which also forms the body of the bobbin, is formed between the second end partition flange 32 and the winding partition flange 34. The bobbin 10 is made of a plastic such as PPS, PET, PBT, LCP, or nylon, but may be made of other insulating materials.

[0037] As shown in Figure 4A, the first end partition flange 30 is positioned above the first winding portion 40 in the Z-axis direction. A first lead drawer base 12 is formed on the outer side of the first end partition flange 30 along the Y-axis. Tapered surfaces 12a, 12a are formed on the inner side of the first lead drawer base 12 along the Y-axis, inclined toward the center of the X-axis. The tapered surfaces 12a, 12a are formed to contact the inclined surfaces 63b1, 63b1 on the outer side of the base portion 62b of one of the divided cores 60b shown in Figure 5A, along the Y-axis.

[0038] As shown in Figure 4A, the first lead extraction base 12 has first passage portions 16a and 16b extending along the Z-axis, and a separation projection 13 is formed between the first passage portions 16a and 16b. The first lead mounting portions 14a and 14b are formed on the outer side of the center in the Y-axis direction of the first lead extraction base 12. The first lead mounting portions 14a and 14b have first groove portions 14a1 and 14b1 extending outward from the center in the Y-axis direction. The inner side of the first groove portions 14a1 and 14b1 in the Y-axis direction is connected to the upper side of the first passage portions 16a and 16b in the Z-axis direction.

[0039] As shown in Figure 4A, a second lead drawer base 22 is formed on the first end partition flange 30. The second lead drawer base 22 is positioned outward from the center in the Y-axis direction, opposite to that of the first lead drawer base 12.

[0040] On the inner side of the second lead drawer base 22 along the Y-axis, tapered surfaces 22a, 22a are formed, inclined toward the center of the X-axis. The tapered surfaces 22a, 22a are formed to contact the inclined surfaces 63b2, 63b2 of the base portion 62b of the other divided core 60b shown in Figure 5A, which are located outside the center along the Y-axis.

[0041] As shown in Figure 4A, the second lead extraction table 22 has a second passage portion 26 that extends along the Z-axis. Second lead mounting portions 24a and 24b are formed on the outer side of the center of the second lead extraction table 22 in the Y-axis direction.

[0042] As shown in Figure 4B, the second lead mounting portions 24a and 24b have second grooves 24a1 and 24b1 formed therein. The second groove 24a1 is L-shaped, having a first portion along the X-axis and a second portion along the Y-axis. The first portion of the second groove 24a1 is connected to the second passage portion 26, and the second portion of the second groove 24a1 extends outward from the center in the Y-axis direction. The first portion of the second groove 24b1 is connected to the upper part of the second passage portion 26 in the Z-axis direction.

[0043] A first insertion hole 31 is formed in the first end partition flange 30. The first insertion hole 31 corresponds to the shape of the second sub-intermediate leg portions 66b2, 66b2 shown in Figure 5A. The first insertion hole 31 is positioned to overlap with the second sub-through hole 54. The second sub-intermediate leg portion 66b2 is inserted into the first insertion hole 31.

[0044] As shown in Figure 4C, the first winding section 40 extends along the Z-axis. The central axis O1 of the first winding section 40 (the winding axis of the first coil section 74 shown in Figure 2B) is positioned outward along the X-axis with respect to the central axis O of the first main through hole 42. The first coil section 74 shown in Figure 2B is formed along the circumferential surface 41 of the first winding section 40. Note that the central axis O1 and central axis O are parallel to the Z-axis.

[0045] As shown in Figure 4D, the first winding portion 40 has a first main through hole 42. As shown in Figure 2C, the first main through hole 42 communicates with the second main through hole 52. The first main through hole 42 corresponds to the shape of the main central leg portions 64b, 64b shown in Figure 5A. As shown in Figure 4D, dividing pieces 47, 47 are formed in the first main through hole 42. The dividing pieces 47, 47 abut against the dividing surfaces 611b of the main central leg portions 64b, 64b shown in Figure 5A, dividing the divided cores 61b, 61b along the Y axis.

[0046] As shown in Figure 4D, the first winding portion 40 has a first sub-through hole 44. As shown in Figure 2C, the first sub-through hole 44 is connected to the winding partition flange 34. The first sub-through hole 44 corresponds to the shape of the first sub-intermediate leg portions 66b1, 66b1 shown in Figure 5A. As shown in Figure 4D, a dividing piece 48 is formed in the first sub-through hole 44. The dividing piece 48 abuts against the dividing surface 611b of the first sub-intermediate leg portions 66b1, 66b1 shown in Figure 5A, dividing the divided cores 61b, 61b along the Y axis.

[0047] As shown in Figure 4D, a first insulating wall 46 is formed between the first main through hole 42 and the first sub-through hole 44. The first insulating wall 46 is positioned between the main intermediate legs 64b, 64b and the first sub-intermediate legs 66b1, 66b1 shown in Figure 5A, and insulates the main intermediate legs from the first sub-intermediate legs.

[0048] As shown in Figure 4C, a winding partition flange 34 is formed below the first winding section 40 in the Z-axis direction. A notch 35 is formed in the winding partition flange 34 at a position corresponding to the lower part of the second passage section 26 in the Z-axis direction. That is, the notch 35 is positioned offset outward from the center in the X-axis direction. As shown in Figure 2B, the second lead sections 82a and 82b are drawn out from the second coil section 84 in the Z-axis direction upward through the notch 35 and the second passage section 26.

[0049] As shown in Figure 4C, the second winding section 50 extends along the Z-axis. The central axis O2 of the second winding section 50 (the winding axis of the second coil section 84 shown in Figure 2B) is positioned outward along the X-axis with respect to the center line O of the second main through hole 52 (the central axis O of the main through hole 42 shown in Figure 4A). The central axis O2 is parallel to the Z-axis.

[0050] In this embodiment, the second winding portion 50 has a shape corresponding to the first winding portion 40. The first winding portion 40 and the second winding portion 50 are symmetrical with respect to the central axis Lx, which passes through the central axis O shown in Figures 4D and 4E and is parallel to the X-axis.

[0051] As shown in Figure 4E, the second winding portion 50 has a second main through hole 52. As shown in Figure 2C, the second main through hole 52 corresponds to the shape of the main central leg portions 64a, 64a shown in Figure 5A. As shown in Figure 4E, dividing pieces 57, 57 are formed in the second main through hole 52. The dividing pieces 57, 57 abut against the dividing surface 611a of the main central leg portions 64a, 64a shown in Figure 5A, dividing the divided cores 61a, 61a along the Y axis.

[0052] As shown in Figure 4E, the second winding section 50 has a second sub-through hole 54. As shown in Figure 2C, the second sub-through hole 54 is connected to the winding partition flange 34. The second sub-through hole 54 corresponds to the shape of the second sub-intermediate leg sections 66a2, 66a2 shown in Figure 5A. As shown in Figure 4E, a dividing piece 58 is formed in the second sub-through hole 54. The dividing piece 58 abuts against the dividing surface 611a of the second sub-intermediate leg sections 66a2, 66a2 shown in Figure 5A, dividing the divided cores 61a, 61a along the Y axis.

[0053] As shown in Figure 4E, a second insulating wall 56 is formed between the second main through hole 52 and the second sub-through hole 54. The second insulating wall 56 is positioned between the main central legs 64a, 64a and the second sub-central legs 66a1, 66a1 shown in Figure 5A, and insulates the main central legs from the second sub-central legs.

[0054] As shown in Figure 4A, the second end partition flange 32 is positioned below the second winding portion 50 in the Z-axis direction. Convex portions 32a and 32b are formed on both outer sides of the second end partition flange 32 relative to its center along the Y-axis.

[0055] On the inner side of the convex portions 32a and 32b along the Y-axis, tapered surfaces 32a1 and 32b1 are formed, similar to the tapered surfaces 12a and 12a, and are inclined toward the center along the X-axis. Tapered surface 32a1 is formed to contact the inclined surface 63a1 of the base portion 62a of the divided core 61a shown in Figure 5A, which is located outside the center along the Y-axis. Tapered surface 32a2 is formed to contact the inclined surface 63a2.

[0056] A second insertion hole 33 is formed in the second end bulkhead flange 32. The second insertion hole 33 corresponds to the shape of the first sub-intermediate leg portions 66a1, 66a1 shown in Figure 5A. The second insertion hole 33 is positioned to overlap with the first sub-through hole 44. The first sub-intermediate leg portion 66a1 is inserted into the second insertion hole 33.

[0057] As shown in Figures 2A and 2B, the bobbin 10 is wound with a first wire 70 and a second wire 80. The wires 70 and 80 may be made of the same material or different materials. The outer diameter of each wire 70 and 80 is not particularly limited, but is preferably in the range of 1.0 to 4.0 mm. It is also preferable that each wire 70 and 80 has an insulating coating formed on it.

[0058] The first wire 70 has a first coil portion 74 wound around the first winding portion 40 of the bobbin 10, and the second wire 80 has a second coil portion 84 wound around the second winding portion 50 of the bobbin 10. As shown in Figure 2C, the first coil portion 74 is positioned between the first end partition flange 30 and the winding partition flange 34. The second coil portion 84 is positioned between the second end partition flange 32 and the winding partition flange 34.

[0059] As shown in Figures 2A and 2B, the winding axis O1 of the first coil section 74 is offset to one side along the X-axis from the center line O of the transformer (the center axis O of the first main through-hole 42 and the second main through-hole 52 shown in Figure 4A). Also, the winding axis O2 of the second coil section 84 is offset to the opposite side of the X-axis from the center line O, from the winding axis O1 of the first coil section 74. The winding axis O1 of the first coil section 74 and the winding axis O2 of the second coil section 84 coincide in the Z-axis direction.

[0060] As shown in Figure 3, the first coil portion 74 has a first coil outer portion 76 which is located outside the center along the X-axis relative to the center line L1 which passes through the winding axis O1 and is along the Y-axis, and a first coil inner portion 78 which is located inside the center line L1 along the X-axis.

[0061] As shown in Figure 2C, the outer portion 76 of the first coil passes between the first outer leg portion 68b1 and the first secondary middle leg portion 66b1. The inner portion 78 of the first coil passes between the main middle leg portion 64b and the second secondary middle leg portion 66b2.

[0062] As shown in Figure 6, the first wire 70 has first lead portions 72a and 72b drawn out from the first coil portion 74. Each end of the first lead portions 72a and 72b is electrically connected by a connecting terminal 73, for example, made of a metal terminal, by soldering or the like.

[0063] As shown in Figure 2A, the first lead portion 72a is drawn out upward in the Z-axis direction toward the first passage portion 16a. The first lead portion 72a passes through the first groove portion 14a1 and is drawn outward from the center in the Y-axis direction.

[0064] As shown in Figure 2A, the first lead portion 72b is drawn out upward in the Z-axis direction toward the first passage portion 16b. The first lead portion 72b passes through the first groove portion 14b1 and is drawn outward from the center in the Y-axis direction.

[0065] As shown in Figure 3, the second coil portion 84 has a second coil outer portion 86 which is positioned outward along the X-axis from the center line L2 which passes through the winding axis O2 and is aligned with the Y-axis, and a second coil inner portion 88 which is positioned inward along the X-axis from the center line L2.

[0066] As shown in Figure 2C, the outer portion 86 of the second coil passes between the second outer leg portion 68a2 and the second secondary middle leg portion 66a2. The inner portion 88 of the second coil passes between the main middle leg portion 64a and the first secondary middle leg portion 66a1.

[0067] As shown in Figure 6, the second wire 80 has second lead portions 82a and 82b that are drawn out from the second coil portion 84. Each end of the second lead portions 82a and 82b is electrically connected by a connection terminal 83, for example, made of a metal terminal, by soldering or the like.

[0068] As shown in Figure 2B, the second lead portions 82a and 82b are drawn out upward in the Z-axis direction toward the second passage portion 26 through the notch 35. The second lead portion 82a is drawn out from the second passage portion 26 toward the outside of the center in the Y-axis direction, passing through the first and second portions of the second groove portion 24a1 shown in Figure 4B. With this configuration, the second lead portion 82a is drawn out while maintaining insulation from the first coil portion 74.

[0069] As shown in Figure 2B, the second lead portion 82b is drawn out upward in the Z-axis direction toward the second passage portion 26b. The second lead portion 82b passes through the second groove portion 24b1 and is drawn outward from the center in the Y-axis direction.

[0070] In this embodiment, as shown in Figure 2C, the first coil section 74 is wound around the first winding section 40, and the second coil section 84 is wound around the second winding section 50. The first winding section 40 and the second winding section 50 are separated by a winding partition flange 34, ensuring insulation between the first coil section 74 and the second coil section 84.

[0071] The first winding section 40 has a first main through hole 42 in which the main middle leg portion 64b is positioned, and a first sub-through hole 44 in which the first sub-middle leg portion 66b1 is positioned. Therefore, the main middle leg portion 64b and the first sub-middle leg portion 66b1 are positioned inside the first coil section 74, and insulation between the first coil section 74 and the core 60b is ensured.

[0072] The second winding section 50 has a second main through-hole 52 in which the main central leg portion 64a is positioned, and a second secondary through-hole 54 in which the second secondary central leg portion 66a2 is positioned. Therefore, the main central leg portion 64a and the second secondary central leg portion 66a2 are positioned inside the second coil section 84, and insulation between the second coil section 84 and the core 60a is ensured.

[0073] The second sub-center leg portion 66b2 of core 60b is positioned between the second outer leg portion 68b2 of core 60b and the inner portion 78 of the first coil of the first coil portion 74. In other words, the second sub-center leg portion 66b2 is positioned outside the first coil portion 74. Also, the first sub-center leg portion 66a1 of core 60a is positioned between the first outer leg portion 68a1 of core 60a and the inner portion 88 of the second coil of the second coil portion 84. In other words, the first sub-center leg portion 66a1 is positioned outside the second coil portion 84.

[0074] With the coils and sub-center legs arranged in this manner, leakage flux is generated in the sub-center legs even without large gaps between the coils, ensuring leakage. This eliminates the need for a choke coil structure and allows for miniaturization of transformer 1. Furthermore, transformer 1 has reduced AC resistance, resulting in low copper losses.

[0075] In this embodiment, as shown in Figure 5A, core 60a is divisible into two divided cores 61a, 61a, and the divided cores 61a, 61a are symmetrical. Core 60b is divisible into two divided cores 61b, 61b, and the divided cores 61b, 61b are symmetrical. This configuration makes it easy to attach the cores to the bobbin.

[0076] Furthermore, the split core 61a and the split core 61b are symmetrical, and each split core has a symmetrical structure with respect to the Z-axis. Therefore, the split cores can be swapped and still function similarly, thereby reducing manufacturing costs.

[0077] In this embodiment, as shown in Figure 3, the winding axis O1 of the first coil section 74 and the winding axis O2 of the second coil section 84 are offset along the X-axis in this horizontal leakage transformer. However, as shown in Figures 4D and 4E, the first winding section 40 and the second winding section 50 have corresponding shapes of the same size. Therefore, as shown in Figure 2C, it is easy to match the inductances of the first coil section 74 and the second coil section by setting the turns ratio to 1:1. With such a transformer 1, switching losses can be prevented.

[0078] In this embodiment, as shown in Figure 2C, a base portion 62a positioned below the Z-axis direction and extending in the X-axis direction, and a base portion 62b positioned above the Z-axis direction and extending in the X-axis direction, sandwich the first coil portion 74 and the second coil portion 84. In addition, a first outer leg portion and a second outer leg portion extending along the Z-axis sandwich the first coil portion 74 and the second coil portion 84 from both sides in the X-axis direction. With this configuration, the first coil portion 74 and the second coil portion 84 can be housed between the cores 60a and 60b, making it possible to manufacture a small transformer with a roughly rectangular parallelepiped shape.

[0079] In this embodiment, as shown in Figure 5B, a gap 100a of distance T1 is formed between the first sub-center legs 66a1 and 66b1, and a gap 100b of distance T1 is formed between the second sub-center legs 66a2 and 66b2. In addition, a gap 101 of distance T2 is formed between the main center leg 64a and the main center leg 64b. Distance T1 is configured to be longer than distance T2. The transformer 1 can adjust leakage using these gaps and can also prevent cracking and chipping of the legs. Note that the distances of these gaps can be changed as needed, and the transformer can function as a leakage transformer even without gaps.

[0080] It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways within the scope of the present invention.

[0081] In the above-described embodiment, as shown in Figure 5A, both cores 60a and 60b are E-type cores having five legs, but either core may be an I-type core without legs. In this case, the legs of the E-type core are abutted against the I-type core. [Explanation of Symbols]

[0082] 1… Trans 10… Bobbin 12…First lead drawer unit 13... Separation protrusion 14a, 14b... First lead mounting section 14a1,14b1...first groove part 16a, 16b...1st passage section 22...Second lead drawer unit 24a, 24b... Second lead mounting section 24a1, 24b1…Second groove part 26…Second passage section 30...First end bulkhead flange 31…First insertion hole 32... Second end bulkhead flange 32a, 32b...Convex part 33…Second insertion hole 34... Wrapped partition guard 35... Notch 40...Volume 1 41...peripheral surface 42…First main through hole 44…First secondary through hole 46…First insulation wall 47,48...divided piece 50...Volume 2 51...peripheral surface 52...Second main through hole 54...Second secondary through-hole 56…Second insulation wall 57,58…divided piece 60a, 60b... core 61a, 61b… Split core 611a,611b…Divided plane 62a...Base section (core part 1) 62b...Base section (second core part) 63a1, 63a2, 63b1, 63b2...slanted surface 64a, 64b…Main middle leg 65a,65b...end face 66a1,66b1...1st secondary middle leg 66a2,66b2…Second secondary middle leg 67a1,67b1...end face 67a2,67b2…end face 68a1,68b1...First outer leg 68a2,68b2…Second outer leg 69a1,69b1...end face 69a2,69b2...end face 70…First wire 72a, 72b... First lead section 73…Connection terminals 74...First coil section 76...Outer part of the first coil 78...Inner part of the first coil 80...Second wire 82a, 82b... Second lead section 83…Connection terminals 84...Second coil section 86...Outer part of the second coil 88...Inner part of the second coil 90...cases 91...Fixed part 92…Bottom plate 100a, 100b... gap (first gap) 101... Gap (Second Gap)

Claims

1. Bobbin and, A first wire having a first coil portion wound around the bobbin, A second wire having a second coil portion wound around the bobbin, A coil device having a core attached to the bobbin, The aforementioned core is A base portion extending in the first axial direction, The main central leg portion is positioned approximately in the center of the base portion in the first axial direction, In the base portion, a first sub-center leg portion is positioned on one side in the first axial direction relative to the main center leg portion, The base portion has a second sub-intermediate leg portion located on the other side in the first axial direction, The main central leg portion is positioned inside the first coil portion and the second coil portion. The first sub-center leg is positioned inside the first coil section and outside the second coil section. The second sub-center leg portion is positioned inside the second coil portion and outside the first coil portion. The core comprises a first core portion including at least a first base portion which is part of the base portion, and a second core portion including at least a second base portion which is another part of the base portion and is substantially parallel to the first base portion. The first core portion and the second core portion sandwich the first coil portion and the second coil portion along the winding axis of the first coil portion. A first gap is formed in the first sub-mid leg portion. A coil device in which the main central leg portion does not have a second gap.

2. Bobbin and, A first wire having a first coil portion wound around the bobbin, A second wire having a second coil portion wound around the bobbin, A coil device having a core attached to the bobbin, The aforementioned core is A base portion extending in the first axial direction, The main central leg portion is positioned approximately in the center of the base portion in the first axial direction, In the base portion, a first sub-center leg portion is positioned on one side in the first axial direction relative to the main center leg portion, The base portion has a second sub-intermediate leg portion located on the other side in the first axial direction, The main central leg portion is positioned inside the first coil portion and the second coil portion. The first sub-center leg is positioned inside the first coil section and outside the second coil section. The second sub-center leg portion is positioned inside the second coil portion and outside the first coil portion. The core comprises a first core portion including at least a first base portion which is part of the base portion, and a second core portion including at least a second base portion which is another part of the base portion and is substantially parallel to the first base portion. The first core portion and the second core portion sandwich the first coil portion and the second coil portion along the winding axis of the first coil portion. The first secondary leg portion does not have a first gap. A coil device having a second gap formed in the main central leg portion.

3. Bobbin and, A first wire having a first coil portion wound around the bobbin, A second wire having a second coil portion wound around the bobbin, A coil device having a core attached to the bobbin, The aforementioned core is A base portion extending in the first axial direction, The main central leg portion is positioned approximately in the center of the base portion in the first axial direction, In the base portion, a first sub-center leg portion is positioned on one side in the first axial direction relative to the main center leg portion, The base portion has a second sub-intermediate leg portion located on the other side in the first axial direction, The main central leg portion is positioned inside the first coil portion and the second coil portion. The first sub-center leg is positioned inside the first coil section and outside the second coil section. The second sub-center leg portion is positioned inside the second coil portion and outside the first coil portion. The core comprises a first core portion including at least a first base portion which is part of the base portion, and a second core portion including at least a second base portion which is another part of the base portion and is substantially parallel to the first base portion. The first core portion and the second core portion sandwich the first coil portion and the second coil portion along the winding axis of the first coil portion. A first gap is formed in the first sub-mid leg portion. A second gap is formed in the main central leg portion. The distances between the first and second gaps are determined to adjust the leakage. The distance of the second gap is the same as or longer than the distance of the first gap in the coil device.

4. The core has a first outer leg portion and a second outer leg portion arranged on the base portion, The first secondary middle leg is positioned between the first outer leg and the main middle leg. The second sub-center leg is positioned between the second outer leg and the main center leg. The first outer leg portion is positioned outside the first coil portion, The coil device according to any one of claims 1 to 3, wherein the second outer leg portion is arranged outside the second coil portion.

5. The coil device according to claim 4, wherein the cross-sectional area of ​​the main central leg portion is approximately the same as the sum of the cross-sectional areas of the first outer leg portion and the second outer leg portion.

6. The coil device according to any one of claims 1 to 5, wherein the cross-sectional area of ​​the main central leg portion is greater than the cross-sectional area of ​​the first secondary central leg portion.

7. The coil device according to any one of claims 1 to 6, wherein the core is symmetric with respect to an axis of symmetry perpendicular to the first axial direction.

8. The coil device according to any one of claims 1 to 7, wherein the first core portion and the second core portion are symmetrical along the winding axis of the first coil portion.

9. The coil device according to any one of claims 1 to 8, wherein the core is divided along a second axis perpendicular to the first axis and the winding axis of the first coil portion.

10. The bobbin has a first winding section around which the first coil portion is wound, a second winding section around which the second coil portion is wound, and a winding partition flange separating the first winding section and the second winding section. The first winding portion has a first main through hole in which the main middle leg portion is arranged, and a first secondary through hole in which the first secondary middle leg portion is arranged. The second winding portion has a second main through hole in which the main middle leg portion is positioned and a second secondary through hole in which the second secondary middle leg portion is positioned. The coil device according to any one of claims 1 to 9, wherein the first main through hole and the second main through hole are in communication.

Images