JP6520149B2 - Coil device - Google Patents

Description

  The present invention relates to a coil device that can be suitably used as, for example, a relatively large transformer or the like used for applications such as in-vehicle use, and is excellent in heat dissipation.

  For example, Patent Document 1 below is known as a transformer used for charging a battery for an EV, for example. As described above, a high current is applied to a transformer used in a car and the like, and measures for heat dissipation are required.

  Conventionally, a heat sink is provided on the outside of the core, and the lower part of the coil device constituting the transformer is covered with potting resin inside the case to dissipate the heat of the transformer.

  However, in the case of using a potting resin, it is necessary to prepare a case for injecting the resin, and an operation for filling the resin is necessary, which makes various processes complicated. Therefore, there is an increasing demand for a coil device such as a transformer having excellent heat dissipation characteristics without using a case containing potting resin.

  Moreover, in a general transformer, heat generation of the coil is transmitted to the bobbin and a heat transfer path transmitted from the bobbin to the magnetic core is secured. However, for heat transfer from the bobbin to the magnetic core and heat radiation from the magnetic core to the outside There is a problem that it is difficult to efficiently dissipate the heat stored inside the coil portion (inside the bobbin). If the heat dissipation of the coil device is insufficient, the magnetic characteristics may deteriorate due to the overheating of the coil portion.

JP, 2014-36194, A

  The present invention has been made in view of such a situation, and an object thereof is to provide a coil device capable of improving heat dissipation and suppressing deterioration of magnetic characteristics due to overheating of a coil portion.

In order to achieve the above object, a coil device according to the present invention is:
A coil device comprising a magnetic core, a bobbin, and a coil mounted on the outer periphery of the bobbin,
The magnetic core and the heat dissipation member are connected in a heat transferable manner at the core installation portion, and
The bobbin and the heat dissipation member are connected in a heat transferable manner at a bobbin installation portion.

  Although a heat sink is illustrated as a heat radiating member, heat sinks, such as a radiation fin, may be used.

  In the coil device according to the present invention, since the bobbin and the heat dissipation member are connected in a heat transferable manner at the bobbin installation portion, the heat stored in the inside of the bobbin around which the heat generating coil is wound is installed At the portion, the heat is transmitted from the bobbin to the heat dissipation member and the heat is dissipated from the heat dissipation member.

  Further, since the magnetic core and the heat dissipation member are connected in a heat transferable manner at the core installation portion, the heat stored inside the bobbin around which the heat generating coil is wound is transferred from the bobbin to the magnetic core The magnetic core is well transmitted to the heat dissipation member, and the heat is dissipated from the heat dissipation member.

  The heat stored in the inside of the bobbin around which the heat generating coil is wound is transmitted to the heat dissipation member through two paths, and a large amount of heat is dissipated by the heat dissipation member. Therefore, it is possible to cope with the increase in current of the coil device, to improve the heat dissipation, and to suppress the deterioration of the magnetic characteristics due to the overheating of the coil portion. Moreover, in order to improve the heat dissipation of a coil apparatus, the potting resin for improving heat dissipation can also be made unnecessary.

  Preferably, in the bobbin installation portion, a heat conductive resin layer is interposed in a gap between the bobbin and the heat dissipation member. The magnetic core and the heat dissipating member are designed to be in direct contact with each other, and in the bobbin installation portion, the magnetic core and the heat dissipating member are designed by creating a gap between the bobbin and the heat dissipating member. It can be made to contact reliably.

  Then, a heat transfer path from the bobbin to the heat dissipation member is secured by interposing the heat transfer resin layer in the gap. As a result, the heat stored inside the bobbin around which the heat generating coil is wound is properly transferred to the heat dissipation member through two paths, and a large amount of heat is dissipated by the heat dissipation member.

  As a thermally conductive resin layer, a heat conductive grease or a heat conductive resin etc. are illustrated, for example. By interposing the thermally conductive resin layer between the heat radiating member and the bobbin, the air gap is eliminated, the heat conductivity is improved, and the heat radiation is improved.

  Preferably, in the bobbin installation portion, a block having a heat transfer characteristic superior to that of the bobbin is installed between the bobbin and the heat dissipation member. The block can be made of, for example, a metal such as aluminum, and the heat conductivity between the bobbin and the heat dissipation member is further improved, and the heat dissipation characteristics as a whole are also improved.

  The bobbin installation portion may be provided with a recess for receiving the block, and the block may be integrally formed with the heat dissipation member.

  Preferably, the magnetic core is divided into an upper core and a lower core. This configuration makes it easy to assemble the coil device. Preferably, the upper core and the lower core are also configured by divided cores which are respectively divided. In that case, heat dissipation can be further improved by forming a gap between the split cores.

FIG. 1 is a partial perspective view of a transformer as a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the transformer shown in FIG. FIG. 3 is a cross-sectional view of the transformer taken along the line III-III shown in FIG. FIG. 4A is a cross-sectional view of the transformer taken along the line IV-IV shown in FIG. FIG. 4B is a cross-sectional perspective view of the transformer taken along the line IV-IV shown in FIG. FIG. 4C is a cross-sectional view of a transformer according to another embodiment of the present invention, and is a cross-sectional view corresponding to FIG. 4A. FIG. 4D is a cross-sectional view of a transformer according to still another embodiment of the present invention, and is a cross-sectional view corresponding to FIG. 4A. FIG. 4E is a cross-sectional view of a transformer according to still another embodiment of the present invention, and is a cross-sectional view corresponding to FIG. 4A. FIG. 5A is a cross-sectional perspective view of the transformer taken along the line VA-VA shown in FIG. 4A. FIG. 5B is a cross-sectional perspective view of the transformer along the line VB-VB shown in FIG. 4A. FIG. 6 is a perspective view of a transformer according to another embodiment of the present invention. FIG. 7 is an exploded perspective view of the transformer shown in FIG. FIG. 8 is a cross-sectional view of the transformer taken along line VIII-VIII shown in FIG.

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

First Embodiment As shown in FIGS. 1 and 2, the transformer 10 as a coil device according to this embodiment is used, for example, as a transformer such as a reactor, particularly for battery charging of an EV. The transformer 10 includes a bobbin 20, a magnetic core 40, and heat radiation covers 70a and 70b, and is attached to the upper surface of the housing 60. The housing 60 is, for example, a plate-like member to which the transformer 10 is attached, and may be one of automobile parts, and the cooling water is flowing on the back surface (the side opposite to the mounting surface of the transformer 10). good.

  As shown in FIG. 2, the bobbin 20 has a bobbin body 24 and terminal block portions 22 and 23 integrally formed on upper ends of both ends of the bobbin body 24 in the X-axis direction. Lead mounting portions 22a, 22b and 23a, 23b are formed on both ends of the terminal block portions 22 and 23 in the Y-axis direction, respectively, and lead portions (not shown) of first wires to be described later The lead portion (not shown) of the second wire is connected.

  As shown in FIG. 2, in the present embodiment, the magnetic core 40 has an upper core 40 a and a lower core 40 b. These cores 40a and 40b can be separated into two divided cores 42a and 42a and 42b and 42b having the same shape, respectively. In the present embodiment, the divided cores 42a, 42a and 42b, 42b all have the same shape, have a U-shaped cross section in the Z-Y cross section, and are a type of U-shaped core.

  The combination of the pair of split cores 42a and 42a disposed in the upper part in the Z-axis direction forms a so-called E-shaped core having an E-shaped cross section in the Z-Y cross section. The other pair of split cores 42b and 42b arranged at the lower part in the Z-axis direction are also combined to form a so-called E-shaped core having a cross-sectional E shape in the Z-Y cross section.

  Each divided core 42a disposed on the upper side in the Z-axis direction includes a base portion 44a extending in the Y-axis direction, a pair of middle leg portions 46a projecting in the Z-axis direction from both ends in the Y-axis direction of the base portion 44a And a leg portion 48a. Each divided core 42b disposed on the lower side in the Z-axis direction includes a base portion 44b extending in the Y-axis direction, a pair of middle leg portions 46b projecting in the Z-axis direction from both ends in the Y-axis direction of the base portion 44b and And side legs 48b.

  As shown in FIG. 2, the pair of middle legs 46 a are inserted into the core leg through holes 26 of the bobbin 20 from above in the Z-axis direction. Similarly, the pair of middle legs 46b are inserted into the core leg through hole 26 of the bobbin 20 from the lower side in the Z-axis direction, and in the through hole 26, their tips are the tips of the middle leg 46a. Contact or face each other at a predetermined gap.

  In the inside of the through hole 26, the separation plate 27 (see FIG. 2) or the convex portion is along the Z axis direction along the X axis direction so as to divide the through hole 26 in the Y axis direction at the central portion. It may be formed. The separation plate 27 (also the projection) is interposed between the pair of middle legs 42a, 42a and between the middle legs 42b, 42b, and these middle legs 42a, 42a or The middle legs 42 b and 42 b are configured to face each other at a predetermined gap and not to contact with each other in the through hole 26. The predetermined gap can be adjusted by the thickness of the separation plate 27 in the Y-axis direction.

  The middle legs 42a, 42a or the middle legs 42b, 42b have an elliptic cylindrical shape elongated in the X-axis direction so as to match the inner peripheral surface shape of the through hole 26 in the combined state. The shape is not particularly limited, and may be changed in accordance with the shape of the through hole 26. The side legs 48a and 48b have an inner concave curved shape that matches the outer peripheral surface shape of the bobbin main body 24, and the outer surface has a flat surface parallel to the XZ plane. In the present embodiment, the material of each of the divided cores 42a and 42b may be a soft magnetic material such as metal or ferrite, but is not particularly limited.

  In the drawing, the X-axis, the Y-axis and the Z-axis are perpendicular to each other, and the Z-axis coincides with the winding axes of the first wire 37 and the second wire 38 described later, and the height (thickness Corresponding to). In the present embodiment, the lower side in the Z-axis direction of the transformer 10 is the installation surface of the transformer (the surface of the housing 60). The Y axis coincides with the direction in which the pair of split cores 42a, 42a or the pair of split cores 42b, 42b are split. Furthermore, the X-axis coincides with the longitudinal direction of the middle legs 46a, 46b.

  As shown in FIG. 3, at both ends in the Z-axis direction of the winding cylindrical portion 28 of the bobbin 20 in the transformer 10 of the present embodiment, end partition ridges 31 and 32 are extended outward in the radial direction. It is integrally molded substantially parallel to the -Y plane. The outer peripheral surface of the winding cylindrical portion 28 located between the end partition wall ridges 31 and 32 in the Z-axis direction is predetermined in the Z-axis direction so that the wound partition wall ridges 33 to 36 project radially outward. It is formed at intervals.

  By the wound partition walls 33 to 36 formed between the end partition walls 31 and 32, winding sections S1 to S5 are formed between the partition walls in this order from the bottom of the Z-axis direction. Ru. In addition, the number of winding partition rib 33-36 and winding division S1-S5 is not specifically limited.

  In the present embodiment, the first wire 37 is wound continuously in the winding sections S1 and S2, and the second wire 38 is wound continuously in the sections S3 to S5. In the present embodiment, the first wire 37 constitutes a primary coil and the second wire 38 constitutes a secondary coil, but may be reversed.

  Further, in the present embodiment, as shown in FIGS. 5A and 5B, at least one communication groove 33a connecting the adjacent sections S1 and S2 is formed in the wound partition rib 33. As shown in FIG. 5B, the first wire 37 wound in the section S1 is passed through the section S2 through the communication groove 33a, and can be wound around the outer circumference of the winding cylindrical portion 28 of the bobbin 20 in this section S2. ing.

  Further, as shown in FIG. 5A, the wound partition weir 36 is formed with at least one communication groove 36a for connecting the adjacent sections S4 and S5 to each other. The second wire 38 wound in the section S4 is passed through the section S5 through the communication groove 36a, and can be wound around the outer circumference of the winding cylindrical portion 28 of the bobbin 20 in the section S5.

  Although not shown, in the wound partition weir 35, a connecting groove similar to the connecting groove 36a is formed. In addition, with regard to the winding ridge 34, in order to insulate the first wire 37 and the second wire 38, it is not necessary to form a connection groove similar to these. In the present embodiment, it is preferable that the communication groove 32a for the first wire 37 and the communication groove 36a for the second wire 38 are formed on mutually opposite sides in the X-axis direction.

  As shown in FIG. 3, the section width T1 along the Z axis in each of the sections S1 and S2 in which the first wire 37 is wound is set to a width in which only one first wire 37 can enter in the Z axis direction. Yes. However, the section width T1 may be set to a width in which two or more first wires 37 can enter. Further, in the present embodiment, the division widths T1 are preferably all the same, but may be slightly different.

  Further, the section width T2 along the Z axis in each of the sections S3 to S5 in which the second wire 38 is wound is set to a width that allows only one second wire 38 to enter in the Z axis direction. The wire winding parts can be separated from one another in each section. In the present embodiment, the section width T2 along the Z axis in each of the sections S3 to S5 may be the same as or different from the section width T1 in accordance with the wire diameter of the second wire 38.

  In addition, the height (length in the radial direction with respect to the winding axis) H1 of the partition wall 31 to 36 is set to a height at which one or more (one or more layers) wires 37 or 38 can enter. In the form, it is preferably set at a height at which 2 to 8 layers of wire can be wound. The heights H1 of the partition walls 31 to 36 are preferably all the same, but may be different. In the present embodiment, the winding method of the wire 37 or 38 wound in each section S1 to S5 is not particularly limited, and may be normal winding or α winding.

  The wires 37 and 38 may be constituted by a single wire or may be constituted by a stranded wire, and are preferably constituted by an insulation coated conductor. The outer diameters of the wires 37 and 38 are not particularly limited, but in the case of passing a large current, for example, φ1.0 to φ3.0 mm is preferable. The second wire 38 may be the same as the first wire 37 but may be different.

  As shown in FIGS. 4A and 4B, bobbin legs 31a are integrally formed on both ends in the X-axis direction of the end partition weir 31 located at the lowermost part in the Z-axis direction. Each bobbin leg 31a is formed to project downward from both ends in the X-axis direction of the end partition rib 31 in the Z-axis direction, and between the bottom surface of the leg 31a and the heat sink 80, a thermally conductive resin Preferably, a gap for forming the layer 90 is formed.

  That is, as shown in FIG. 4A, the height T3 in the Z-axis direction of the leg 31a is preferably designed to be shorter than the thickness T4 in the Z-axis direction of the base 44b of the lower core 40b. (T4-T3) corresponds to the thickness T5 of the thermally conductive resin layer 90. The thickness T5 of the heat conductive resin layer 90 is preferably as small as possible, but a certain thickness is required to absorb the manufacturing error.

  By securing the thickness T5 of the thermally conductive resin layer 90, the adhesion between the magnetic core 40 and the bobbin 20 is improved even if there is a manufacturing error of each of the divided cores 40a and 40b of the magnetic core 40 or a manufacturing error of the bobbin. The heat transfer characteristics are improved. Further, the bottom surface 41 of the magnetic core 40 can be in direct contact with the surface 2 of the heat dissipation plate 80 at the core installation portion 82 of the heat dissipation plate 80.

  In addition, as the heat conductive resin layer 90, for example, a heat conductive grease or a heat conductive resin is exemplified. By interposing the heat conductive resin layer 90 between the heat sink 80 and the bobbin 40, the air gap is eliminated, the heat conductivity is improved, and the heat radiation is improved. The heat conductive resin layer 90 can also function as an adhesive between the bobbin 20 and the heat sink 80. A resin layer similar to the heat conductive resin layer 90 is interposed between the inner peripheral surface of the core leg through hole 26 of the bobbin 20 shown in FIG. 3 and the outer peripheral surface of the middle legs 46 a and 46 b of the magnetic core 40. Also good.

  The bobbin 20 is made of, for example, a plastic such as PPS, PET, PBT, LCP, or nylon, but may be made of other insulating members. However, in the present embodiment, the bobbin 20 is preferably made of, for example, a plastic having a high thermal conductivity of 1 W / m · K or more, and is made of, for example, PPS, nylon or the like.

  As shown in FIGS. 1 and 2, a pair of heat dissipating covers 70a and 70b are disposed to cover the upper surface in the Z-axis direction and the side surface in the Y-axis direction of the magnetic core 40 after assembly. The heat radiation covers 70a and 70b are each L-shaped in the Z-Y cross section, and have upper surface cover portions 72a and 72b and side surface cover portions 74a and 74b.

  As shown in FIG. 3, the upper surface cover portions 72a and 72b cover the upper surfaces of the split cores 42a and 42a, respectively. The Y-axis direction front end portions 72a1 and 72b1 of the upper surface cover portions 72a and 72b are preferably designed to face each other but not to contact with each other.

  If they are designed to be in contact with each other, the side cover portions 74a and 74b and the side surface (the side surface perpendicular to the Y axis) of the magnetic core 40 face each other due to a manufacturing error of the dimensions of the magnetic core 40. This is because there is a possibility that a gap may be left between them. If a gap is created, the heat transfer characteristics from the magnetic core 40 to the heat dissipation covers 70a and 70b may be degraded. Therefore, it is preferable that the side covers 74a and 74b be in close contact with the side surfaces of the magnetic core 40 facing in the Y-axis direction.

  Of course, it is preferable that the upper surface covers 72 a and 72 b also be in close contact with the upper surface of the magnetic core 40. An adhesive may be used to bring the heat radiation covers 70a and 70b into close contact with the magnetic core.

  The height H2 in the Z-axis direction of the side covers 74a and 74b is preferably designed to be shorter than the height H3 in the Z-axis direction of the combined magnetic core 40. If this height H2 is designed to be equal to or greater than the height H3, the lower ends of the side covers 74a and 74b collide with the upper surface of the housing 60 or the upper surface of the heat sink 80 depending on the manufacturing error of the magnetic core 40 There is a risk of As a result, the adhesion between the upper surface covers 72a and 72b and the upper surface of the magnetic core 40 may be impaired.

  The heat radiation covers 70a and 70b can be formed integrally by bending or pressing a single plate material, for example. Alternatively, a plurality of plate members may be joined by laser welding or the like. The heat radiation covers 70a and 70b are made of a material having a heat transfer characteristic better than that of the magnetic core 40 and the bobbin 20, and are made of, for example, a metal plate of aluminum, copper, stainless steel, brass, iron or the like. The thickness of the metal plate is not particularly limited, but is, for example, 0.2 to 1.5 mm, preferably 0.3 mm to 0.7 mm.

  In the present embodiment, as shown in FIG. 4A, the bobbin 20 and the heat dissipation plate 80 are connected so as to be able to transfer heat through the heat conductive resin layer 90 at the bobbin installation portions 83 located at both ends of the heat dissipation plate 80 in the X axis direction. doing. For this reason, the heat stored in the inside of the bobbin 20 on which the coil-shaped first wire 37 or the second wire 38 is wound is favorably transmitted from the bobbin 20 to the heat dissipation plate 80 at the bobbin installation portion 83. Heat is dissipated from the heat sink 80 through the housing 60.

  The heat sink 80 may be equipped with a heat sink such as a heat radiation fin. In the present embodiment, the heat dissipation plate 80 is made of, for example, the same metal as the heat dissipation covers 70 a and 70 b, and is fixed to the surface of the housing 60. When the case 60 is made of a member having high thermal conductivity such as metal, the heat retained in the center of the bobbin 20 is transferred to the case 60 through the thermally conductive resin layer 90 and the heat dissipation plate 80. Can be missed.

  Further, the magnetic core 40 and the heat sink 80 are connected by the core installation portion 82 so as to be able to transfer heat. For this reason, the heat stored in the inside of the bobbin 20 around which the coil-shaped first wire 37 or the second wire 38 is wound is transmitted from the bobbin 20 to the magnetic core 40, and from the magnetic core 40 to the heat dissipation plate 80. And the heat is dissipated from the heat sink 80 through the housing 60.

  The heat stored inside the bobbin 20 wound with the coiled first wire 37 or the second wire 38 that generates heat in this way is transmitted to the heat sink 80 and the casing 60 through two paths, A large amount of heat is dissipated. Therefore, the large current of the transformer 10 can be coped with, the heat dissipation can be improved, and the deterioration of the magnetic characteristics due to the overheating of the coil portion can be suppressed. Moreover, in order to improve the heat dissipation of the transformer 10, the potting resin for improving the heat dissipation can be eliminated.

  Furthermore, in the transformer 10 according to the present embodiment, winding partition walls 33 to 36 are provided to separate the wire winding portions adjacent to each other along the winding axis (Z axis) of the wire 37 (38). Since the wire 37 (38) has a large outer diameter, it is easy to insulate and easily cope with a large current (high output). Also, in the related art, there is also an adverse effect that adjacent wires mutually affect each other as the voltage becomes higher frequency, making it difficult for current to flow, but in the transformer 10 of this embodiment, the wound partition walls 33 to 36 are used. Such adverse effects can be reduced to improve the high frequency characteristics. Furthermore, since the end partition ribs 31 and 32 and the wound partition ribs 33 to 36 also function as a radiation fin, the heat dissipation of the transformer 10 is also excellent.

  Furthermore, in the present embodiment, in each of the sections S1 to S5, the wire 37 (38) per layer is wound to wind the wire 37 (38) so that only a single wire exists along the winding axis direction. It becomes easy to prevent the variation in the number of turns of the coil and contributes to the stabilization of the coil characteristics. That is, the coupling coefficient K between the primary coil and the secondary coil can be strictly controlled.

  Furthermore, in the present embodiment, the split leg portions 46a and 46b of the split cores 42a and 42b which are split into a U-shaped cross section are inserted into the core leg through holes 26 of the bobbin 20. According to the experiments of the present inventors, even if the core becomes large by such a configuration, compared with the case of using the conventional E-shaped core, at the intersection between the middle leg and the base Local stress that occurs can be dispersed. Therefore, in the transformer 10 according to the present embodiment, the occurrence of a crack or the like can be effectively suppressed even if the thermal stress occurs in the core.

  The middle legs 46a and 46b and the base in the E-shaped core configured by combining the split cores 42a and 42b are separated by the split surface of the split cores 42a and 42b, and a predetermined distance between the split surfaces is determined. It is possible to form a gap, and the heat dissipation is also improved. Furthermore, the E-shaped core is configured by combining a pair of split cores 42a and 42b each having a simple shape, which facilitates the manufacture of the core and can also reduce the manufacturing cost. Moreover, since the split type E-shaped core has the same magnetic flux as that of the E-shaped core as a whole, the magnetic characteristics of the core are equivalent to those of a general E-shaped core.

Second Embodiment As shown in FIG. 4C, the transformer 10a of this embodiment has the same configuration as that of the first embodiment except for the configuration described below, and exhibits the same function and effect. Hereinafter, the description of the overlapping parts is omitted.

  In the transformer 10a of the present embodiment, a recess 31b is formed on the bottom surface of the bobbin leg 31a, and the heat conductive block 100 is attached to the recess 31b. The thermal rolling block is made of, for example, the same metal as the heat sink 80 or a different metal. The heat conductive block 100 may be fixed to the inside of the recess 31 b with an adhesive 90 a or the like. The adhesive 90 a is preferably, for example, the same as the resin constituting the heat conductive resin layer 90, but it is not necessary to be necessarily the same. The bottom surface of the block 100 is preferably flush with the bottom surface of the leg 31a.

  In the bobbin installation portion 83, since the block 100 having a heat transfer characteristic superior to that of the bobbin 20 is installed between the bobbin 20 and the heat dissipation plate 80, the heat conductivity between the bobbin 20 and the heat dissipation plate 80 is This further improves the heat dissipation characteristics as a whole.

  The shape of the recess 31b formed in the bottom of the bobbin leg 31a is not particularly limited. For example, as shown in FIG. 4D, the recess 31b opens toward the end in the X-axis direction and the bottom in the Z-axis direction. It may be. The shape of the block 100 may be changed according to the shape of the recess 31 b.

  Furthermore, as shown in FIG. 4E, in the bobbin mounting portion 83 of the heat sink 80, the heat conductive block 100a may be joined to the heat sink 80 by a means such as welding or may be integrally formed. It is good.

Third Embodiment As shown in FIGS. 6 to 8, the transformer 10b of this embodiment has the same configuration as that of the first embodiment and the second embodiment except for the configuration shown below, and the same function and effect Play. Hereinafter, the description of the overlapping parts is omitted.

  In the transformer 10b of the present embodiment, a recess 31b is formed on the bottom surface of the bobbin leg 31a, and the heat conductive block 100 is attached to the recess 31b. The thermal rolling block is made of, for example, the same metal as the heat sink 80 or a different metal. The heat conductive block 100 may be fixed to the inside of the recess 31 b with an adhesive 90 a or the like. The adhesive 90 a is preferably, for example, the same as the resin constituting the heat conductive resin layer 90, but it is not necessary to be necessarily the same. The bottom surface of the block 100 is preferably flush with the bottom surface of the leg 31a.

  Further, in the present embodiment, the rising pieces 80c are integrally formed with the heat sink 80b at both ends of the heat sink 80b in the X-axis direction. The rising piece 80c covers the lower side surface of the bobbin leg 31a, and has a fitting hole fitted to the fitting protrusion 31c formed on the outer peripheral surface of the bobbin leg 31a.

  In the present embodiment, as shown in FIG. 7, the transformer 10 b of the present embodiment does not have the heat radiation covers 70 a and 70 b shown in FIG. 2, but has a pair of covers 50. The cover main body 52 of the cover 50 is shaped to cover the outer periphery of the bobbin main body 24 located between the terminal blocks 22 and 23 of the bobbin 20b. At both ends in the Z-axis direction of the cover main body 52, locking pieces 54 which are bent in a substantially vertical direction from the cover main body 52 toward the bobbin main body 24 are integrally formed. A pair of locking pieces 54 formed on both sides of the cover main body 52 in the Z-axis direction are attached so as to sandwich the upper and lower surfaces of the bobbin main body 24 in the Z-axis direction.

  Further, side leg guide pieces 56 extending in the Z-axis direction are integrally formed on the outer surfaces of both ends of the cover main body 52 in the X-axis direction. The inner surfaces of the side legs 48a and 48b contact the outer surface of the cover main body 52 located between the pair of side leg guide pieces 56, and movement of the side legs 48a and 48b in the X-axis direction is the pair of side legs It is limited by the guide piece 56. The covers 50 are made of an insulating member such as plastic similar to the bobbin 20b.

  Furthermore, the transformer 10 b of the present embodiment has a lead insulating cover 110. The insulating cover 110 is a second wire 38 wound around the lead portions 37a, 37a and the bobbin 20b while the lead portions 37a, 37a of the first wire go from the lower side in the Z-axis direction toward the upper side in the terminal block 22 direction. It may be used to ensure sufficient insulation from it.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, in the transformers 10, 10a and 10b of the present embodiment, the aspect of division of the magnetic core may be changed. For example, in the embodiment described above, the magnetic core is configured by the combination of the U core and the U core which is a split core, but the magnetic core may be assembled by the combination of the U core and the I core. Further, the shape and structure of the bobbins 20 and 20b, the number of turns and the winding method of the wires 37 and 38, and the like are not limited to the illustrated embodiment, and may be variously modified.

10, 10a, 10b ... Transformers 20, 20b ... Bobbins 22, 23 ... Terminal blocks 22a, 22b, 23a, 23b ... Lead attachment parts 24 ... Bobbin main body 26 ... Core leg through holes 28 ... Winding cylinder parts 31, 32 End partition wall 33 to 36 Winding partition wall 37 First wire 38 Second wire 40 Magnetic core 40a Upper core 40b Lower core 42a, 42b Separated core 44a, 44b Base portion 46a, 46b ... Middle legs 48a, 48b ... Side legs 50 ... Cover 60 ... Housings 70a, 70b ... Heat dissipation cover 80 ... Heat dissipation plate 90 ... Heat conductive resin layer

Claims (4)

A coil device comprising a magnetic core, a bobbin, and a coil mounted on the outer periphery of the bobbin,
In the bobbin, a bobbin leg portion is formed at an end partition rib of the bobbin,
A gap is formed between the bobbin leg and the heat dissipation member,
A thermally conductive resin layer intervenes in the gap,
Said magnetic core and said heat radiating member, with are connected in a heat transfer core installation section,
The bobbin and the heat dissipation member are connected in a heat transferable manner at a bobbin installation portion,
In the bobbin installation portion, the height of the bobbin leg portion is shorter than the thickness of the base portion of the magnetic core,
A coil device characterized in that the thickness of the thermally conductive resin layer corresponds to the difference between the height of the bobbin leg portion and the thickness of the base portion of the magnetic core . The coil device according to claim 1 , wherein in the bobbin installation portion, a block having a heat transfer characteristic superior to that of the bobbin is installed between the bobbin leg and the heat dissipation member. The coil device according to claim 2 , wherein the bobbin leg portion is formed with a recess for receiving the block. The coil device according to claim 2 , wherein the block is integrally formed with the heat dissipation member.

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