Coil device

Abstract

To provide a coil device that has excellent heat dissipation and can effectively prevent damage to a core.SOLUTION: A coil device 10 includes a core assembly 40, and a case 60 that houses at least a part of the core assembly 40. Lower cores 40b and 40b are mounted on the case 60, and a support portion 622 for supporting base surfaces 440b and 440b of the lower cores 40b and 40b is provided at a position separated from the upper surface 620 of a bottom plate 62 of the case 60.SELECTED DRAWING: Figure 7A

Description

[Technical field]

[0001] The present invention relates to a coil device. [Background technology]

[0002] Known technology for improving the heat dissipation of a coil device is, for example, the technology shown in Patent Document 1. The coil device described in Patent Document 1 has a core and a case in which the core is housed, and is capable of dissipating heat generated by the core etc. through the bottom plate of the case.

[0003] However, since there is a difference in the thermal expansion coefficient between the core and the case, when the core is placed directly on the bottom plate of the case, stress acts on the core due to the difference in the thermal expansion coefficient between the two. In particular, when the entire mounting side of the core is brought into intimate contact with the top surface of the bottom plate, as in the coil device described in Patent Document 1, the stress acting on the core becomes large, increasing the possibility of cracks occurring in the core. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-36194 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coil device which has excellent heat dissipation properties and can effectively prevent damage to the core. [Means for solving the problem]

[0006] In order to achieve the above object, a coil device according to a first aspect of the present invention comprises: A core, A case in which at least a portion of the core is housed, The case has a support portion on which the core is placed and which supports the mounting side of the core at a position spaced apart from the upper surface of the bottom of the case.

[0007] In the coil device according to the first aspect of the present invention, the case has a support portion on which the core is placed and which supports the mounting side surface of the core at a position spaced apart from the upper surface of the bottom of the case. Therefore, the mounting side surface of the core is raised above the upper surface of the bottom at positions other than the positions where the support portion is provided, and the entire mounting side surface of the core does not contact the upper surface of the bottom. Therefore, compared to the conventional technology, it is possible to reduce the contact area between the mounting side surface of the core and the bottom, reducing the stress acting on the core due to the difference in thermal expansion coefficient between the two, and preventing the occurrence of cracks in the core.

[0008] In addition, at the position where the support is provided, heat generated in the core, etc. can be propagated to the bottom via the support, and the heat can be dissipated via the bottom. Furthermore, at positions other than the positions where the support is provided, the mounting side of the core is disposed at a position spaced apart from the upper surface of the bottom by the height of the support, and a gap is formed between the mounting side of the core and the upper surface of the bottom. For example, by filling this gap with resin, heat generated in the core, etc. can be dissipated via the resin and the bottom. As described above, according to the present invention, a coil device having excellent heat dissipation properties and capable of preventing damage to the core can be realized.

[0009] Preferably, the case is provided with a plurality of the support parts. With this configuration, the mounting side of the core can be stably supported by the plurality of support parts. Also, the heat generated by the core, etc. can be efficiently transferred to the bottom via the plurality of support parts, and the heat can be effectively dissipated via the bottom.

[0010] Preferably, the support is formed on the bottom and is a first protrusion protruding from the upper surface of the bottom. With this configuration, it is possible to sufficiently reduce the contact area between the mounting side surface of the core and the bottom, and it is possible to effectively reduce the stress on the core caused by the difference in thermal expansion coefficient between the two. Furthermore, by integrally forming the support with the bottom, it is possible to efficiently propagate heat generated in the core, etc. to the bottom via the support, and the heat can be effectively dissipated via the bottom.

[0011] Preferably, the lower surface of the bottom of the case is a flat surface. With this configuration, the surface area of ​​the contact surface between the lower surface of the bottom and the cooling mechanism provided therebelow is increased, so that heat generated in the core, etc. can be effectively dissipated through the bottom.

[0012] The case may be configured to be separable into a side plate and the bottom of the case. Although details will be described later, by configuring in this manner, a support portion can be easily formed at the position where the side plate and the bottom are combined.

[0013] Preferably, the support portion may be formed separately from the bottom portion. In this case, since there is no need to form a support portion on the bottom portion, it is possible to configure the upper surface of the bottom portion in a flat shape, which makes it easier to manufacture the case.

[0014] In order to achieve the above object, a coil device according to a first aspect of the present invention comprises: A core, A case in which the core is placed and in which at least a portion of the core is housed, The mounting side surface of the core is formed with an abutment portion that abuts against the bottom of the case at a position spaced from the mounting side surface of the core.

[0015] In the coil device according to the second aspect of the present invention, a contact portion is formed on the mounting side surface of the core, which contacts the bottom of the case at a position spaced from the mounting side surface of the core. The contact portion performs the same function as the support portion described above, and mainly forms a gap between the mounting side surface of the core and the upper surface of the bottom at a position other than the position where the contact portion is formed, so that the entire mounting side surface of the core does not contact the upper surface of the bottom. In other words, the coil device according to the second aspect of the present invention differs from the coil device according to the first aspect of the present invention in that the mechanism for performing the above-mentioned function is provided on the core side, not on the case side.

[0016] Therefore, in the coil device according to the second aspect of the present invention, the contact area between the core and the bottom of the case is reduced, and the stress acting on the core due to the difference in thermal expansion coefficient between the core and the bottom of the case is reduced, thereby preventing the core from cracking. In addition, in positions other than the positions where the abutment portions are formed, the heat generated in the core, etc. can be effectively dissipated through the resin and the bottom by, for example, filling the gap with resin. In addition, in the positions where the abutment portions are formed, the heat can be propagated to the bottom via the abutment portions and dissipated.

[0017] Preferably, a plurality of the abutment parts are formed on the mounting side surface of the core. In this case, the abutment parts function as legs for mounting the core on the upper surface of the bottom, and the core can be stably mounted on the upper surface of the bottom via the plurality of abutment parts. In addition, heat generated in the core, etc. can be efficiently transferred to the bottom via the plurality of abutment parts, and the heat can be effectively dissipated via the bottom.

[0018] Preferably, the contact portion is a second protrusion protruding from the mounting side of the core. With this configuration, it is possible to sufficiently reduce the contact area between the core and the bottom, and effectively reduce the stress acting on the core due to the difference in thermal expansion coefficient between the two.

[0019] Preferably, the space between the mounting side surface and the bottom portion of the core is filled with resin. With this configuration, as described above, heat generated in the core and the like can be effectively dissipated through the resin and the bottom portion. [Brief description of the drawings]

[0020] [Figure 1A] FIG. 1A is a perspective view of a coil device according to a first embodiment of the present invention. [Figure 1B] FIG. 1B is a perspective view showing a state in which the case is removed from the coil device shown in FIG. 1A. [Diagram 2] FIG. 2 is an exploded perspective view of the coil device shown in FIG. 1A. [Diagram 3] FIG. 3 is a perspective view of the bobbin shown in FIG. [Figure 4] FIG. 4 is a perspective view of the bobbin, the bobbin cover, and the cap member shown in FIG. [Diagram 5] FIG. 5 is a perspective view showing a state in which a bobbin cover is attached to the bobbin shown in FIG. [Figure 6] FIG. 6 is a perspective view showing a state in which the second wire is wound around the bobbin cover shown in FIG. [Figure 7A] FIG. 7A is a cross-sectional view of the coil device taken along line VIIA-VIIA shown in FIG. 1A. [Figure 7B] FIG. 7B is a cross-sectional view of the coil device taken along line VIIB-VIIB shown in FIG. 1A. [Figure 8] FIG. 8 is a perspective view of the case shown in FIG. [Figure 9] FIG. 9 is a perspective view of a coil device according to the second embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view of the coil device taken along line XX shown in FIG. [Figure 11] FIG. 11 is a perspective view of a coil device according to the third embodiment of the present invention. [Figure 12] FIG. 12 is an exploded plan view of the case shown in FIG. [Figure 13]FIG. 13 is a cross-sectional view of the coil device taken along line XIII-XIII shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0022] First embodiment 1A and 1B according to this embodiment is used, for example, as a transformer, and is used in an in-vehicle power supply circuit, etc. The coil device 10 has a core assembly 40 and a case 60 in which at least a portion of the core assembly 40 is housed. Details of the core assembly 40 and the case 60 will be described later.

[0023] As shown in FIG. 2, the coil device 10 includes the core assembly 40 and the case 60, as well as the bobbin 20, the partition cover 50, the heat dissipation cover 70, the cap members 80a, 80b, and the bobbin covers 90a, 90b (FIG. 4). The configuration of each of these members will be described below. In the drawings, the X-axis, the Y-axis, and the Z-axis are perpendicular to each other, and the X-axis coincides with the direction in which the first cores 40a, 40a are arranged. The Y-axis coincides with the direction in which the first seat 25a and the second seat 25b of the bobbin 20 are arranged. The Z-axis corresponds to the height (thickness) of the transformer 10 and is parallel to the winding axes of the coil sections 31, 32 described later.

[0024] As shown in FIG. 3, the bobbin 20 has a bobbin substrate 21. The bobbin substrate 21 is in the shape of a substantially elliptical flat plate and constitutes the bottom of the bobbin 20. Legs 22, 22 are formed at each end of the bobbin substrate 21 in the Y-axis direction. The legs 22 protrude downward from the bobbin substrate 21 and serve to support the bobbin 20. A recess 22a is formed on the bottom surface of the leg 22, and the block 102 shown in FIG. 2 can be disposed inside the recess 22a in the manner shown in FIG. 5. The block 102 is made of a thermally conductive member, for example, a metal.

[0025] A first hollow cylinder 23 is integrally formed so as to extend upward from approximately the center of the bobbin substrate 21. The first hollow cylinder 23 has a cylindrical shape, and a first wire 37 (FIG. 4) is wound around the outer surface of the first hollow cylinder 23. A separation plate fixing portion 28 is formed on the inner surface of the first hollow cylinder 23, and a separation plate 106 can be fixed in the manner shown in FIG.

[0026] The separation plate fixing portion 28 extends in the Z-axis direction and is disposed between the middle legs 46a, 46a of the two first cores 40a, 40a facing each other in the X-axis direction and between the middle legs 46b, 46b of the second cores 40b, 40b. The separation plate fixing portion 28 is intended to prevent the middle legs 46a, 46a (middle legs 46b, 46b) facing each other in the X-axis direction from coming into contact with each other with a predetermined gap inside the first hollow cylinder portion 23. The separation plate portion 106 fixed to the separation plate fixing portion 28 also has a similar function.

[0027] A bobbin upper flange 24 is formed at the top of the first hollow cylinder 23. The bobbin upper flange 24 is integrally formed at the upper end of the first hollow cylinder 23 and protrudes in the radial direction in a direction parallel to the XY plane. A pedestal 25a is integrally formed at one end of the bobbin upper flange 24 in the Y-axis direction, and a pedestal 25b is integrally formed at the other end. Since the pedestal 25a and the pedestal 25b have the same configuration, a description of the configuration of the pedestal 25b will be omitted below.

[0028] The base 25a has a bottom surface portion 250. The bottom surface portion 250 constitutes the bottom surface of the base 25a, and has a shape that is elongated in the X-axis direction. An insulating wall 251 and outer walls 252a to 252c are formed around the bottom surface portion 250 so as to surround it. The insulating wall 251 and the outer walls 252a to 252c are formed so as to protrude upward.

[0029] The insulating wall 251 is formed on the bottom surface portion 250 at the boundary with the bobbin upper flange portion 24. The insulating wall 251 serves to prevent the base portions 46a, 46a of the first cores 40a, 40a shown in FIG. 2 from contacting the second lead portion 38a of the second wire 38 passing through the inside of the pedestal 25a when the first cores 40a, 40a shown in FIG.

[0030] The outer walls 252a to 252c are formed to face the insulating wall 251 in the Y-axis direction. The outer wall 252a is formed integrally with the insulating wall 251, and a part of the outer wall 252a extends along one end of the bottom surface portion 250 in the X-axis direction. The other end of the bottom surface portion 250 in the X-axis direction is open so that the second lead portions 38a, 38b of the second wire 38 shown in FIG. 2 can be drawn out. In the base 25b, the other end of the bottom surface portion 250 in the X-axis direction is open so that the first lead portions 37a, 37b of the first wire 37 can be drawn out.

[0031] Outer walls 252a and 252b are adjacent to each other in the X-axis direction with outer wall cutout 253a in between, and outer walls 252b and 252c are adjacent to each other in the X-axis direction with outer wall cutout 253b in between. Bottom portion 250 is formed with bottom cutout 254a so as to be continuous with outer wall cutout 253a in the Y-axis direction, and bottom cutout 254b so as to be continuous with outer wall cutout 253b in the Y-axis direction.

[0032] A partition wall 255 is formed between the insulating wall 251 and the outer wall 252c. The partition wall 255 is disposed approximately parallel to the insulating wall 251 and the outer wall 252c, and extends along the X-axis direction.

[0033] A first insertion passage 256a is formed on one side of the partition wall 255 in the Y-axis direction. The first insertion passage 256a is for inserting the second lead portion 38b of the second wire 38 shown in FIG. 2. The first insertion passage 256a extends from the position where the bottom cutout 254a is formed along the outer walls 252b and 252c toward the X-axis direction while straddling the bottom cutout 254b. In the base 25b, the first insertion passage 256a is for inserting the first lead portion 37a of the first wire 37 shown in FIG. 2.

[0034] A second insertion passage 256b is formed on the other side of the partition wall 255 in the Y-axis direction. The first insertion passage 256b is for inserting the second lead portion 38a of the second wire 38 shown in FIG. 2. The second insertion passage 256b extends from the position where the bottom cutout portion 254b is formed along the partition wall 255 toward the X-axis direction. The extension directions of the second insertion passage 256b and the first insertion passage 256a are approximately parallel to each other. In the base 25b, the first lead portion 37b of the first wire 37 shown in FIG. 2 is inserted into the second insertion passage 256b.

[0035] An engaging protrusion 257a is formed on an outer surface located on one side in the X-axis direction of the insulating wall 251, and an engaging protrusion 257b is formed on an outer surface located on the other side. The engaging protrusions 257a and 257b are for engaging with engaging recesses 82a and 82b formed in a cap member 80a, which will be described later. In the base 25b, the engaging protrusions 257a and 257b are engaged with the engaging recesses 82a and 82b of the cap member 80b.

[0036] A plurality of positioning protrusions 26 are formed on the outer peripheral surface of the first hollow cylinder 23 at a predetermined interval along the circumferential direction of the first hollow cylinder 23. Each positioning protrusion 26 is formed at the lower end of the outer peripheral surface of the first hollow cylinder 23 and protrudes radially outward from the outer peripheral surface. The positioning protrusions 26 are provided to position the bobbin covers 90a, 90b (FIG. 4) attached to the outer periphery. When the bobbin covers 90a, 90b are attached to the bobbin 20, the inner peripheral surface of the second hollow cylinder 91 of the bobbin covers 90a, 90b can be positioned at a position spaced apart from the outer peripheral surface of the first hollow cylinder 23 by the radial protrusion length of the positioning protrusions 26.

[0037] A first wire fixing portion 27 is formed on the outer peripheral surface of the first hollow cylinder portion 23. The first wire fixing portion 27 is formed at a position spaced upward from the positioning protrusion 26 by approximately the width of one wire of the first wire 37. The first wire fixing portion 27 protrudes radially outward from the outer peripheral surface of the first hollow cylinder portion 23. The first wire fixing portion 27 has a thin plate shape, but the shape is not particularly limited. The first lead portion 37b of the first wire 37 can be hooked and fixed to the first wire fixing portion 27. The first wire 37 can be inserted into the gap between the first wire fixing portion 27 and the positioning protrusion 26.

[0038] As shown in Fig. 5, a fitting groove 29 is formed on the bottom surface of the base 25a. The fitting groove 29 is formed in approximately the center of the base 25a in the X-axis direction and extends along the Y-axis direction. The fitting groove 29 is a groove of a predetermined depth, into which the upper end of the cover partition portion 94a of the bobbin cover 90a can be fitted. In the base 25b, the upper end of the cover partition portion 94b of the bobbin cover 90b is fitted into the fitting groove 29.

[0039] 4, a first wire 37 is wound around the outer circumferential surface of the first hollow cylinder 23. More specifically, the first wire 37 is wound in a plurality of turns above the first wire fixing portion 27 on the outer circumferential surface of the first hollow cylinder 23, and is wound in one turn below the first wire fixing portion 27 (at the lower end of the first hollow cylinder 23). As a result, a first coil portion 31 formed by winding the first wire 37 is formed on the outer circumferential surface of the first hollow cylinder 23.

[0040] The first lead portion 37b of the first wire 37 rises from a position below the first wire fixing portion 27 toward the pedestal 25b. More specifically, the first lead portion 37b rises upward while being hooked on the first wire fixing portion 27, and is guided from the outside to the inside of the pedestal 25b via the outer wall cutout portion 253b. The first lead portion 37b is guided further toward the inside of the pedestal 25b via the bottom surface cutout portion 254b, and is pulled out to the outside in the X-axis direction while passing through the inside of the second insertion passage 256b in a state in which it is bent substantially vertically toward the positive direction of the X-axis.

[0041] On the other hand, the first lead portion 37a rises from the upper end of the outer circumferential surface of the first hollow cylinder portion 23 toward the pedestal 25b. More specifically, the first lead portion 37a is guided from the outside to the inside of the pedestal 25b via the outer cutout portion 253a. The first lead portion 37a is guided further toward the inside of the pedestal 25b via the bottom cutout portion 254a, and is pulled out to the outside in the X-axis direction while passing through the inside of the first insertion passage 256a in a state in which it is bent substantially vertically toward the positive direction of the X-axis.

[0042] The bobbin covers 90a, 90b are attached to the bobbin 20 with the first wire 37 wound around the outer peripheral surface of the first hollow cylinder portion 23. Each of the bobbin covers 90a, 90b is composed of a split half that can be combined with each other. In the following, with regard to the overlapping configurations of the bobbin covers 90a, 90b, only the bobbin cover 90a will be described, and a description of the bobbin cover 90b will be omitted.

[0043] The bobbin cover 90a has a second hollow cylinder portion 91. The second hollow cylinder portion 91 is composed of a half-split body, and when the second hollow cylinder portion 91 of the bobbin cover 90a and the second hollow cylinder portion 91 of the bobbin cover 90b are combined, a cylindrical body is formed. The second wire 38 can be wound around the outer circumferential surface of the second hollow cylinder portion 91.

[0044] A cover partition 94a is formed on the outer circumferential surface of the second hollow cylinder 91. The cover partition 94a is formed on the upper end of the second hollow cylinder 91 and protrudes outward from the outer circumferential surface of the second hollow cylinder 91. The cover partition 94a has a predetermined length in the Z-axis direction, and its upper end is fitted into the fitting groove 29 of the base 25a in a manner as shown in FIG.

[0045] A pair of upper cover flanges 92a, 92a are formed on the upper part of the second hollow cylinder 91. One upper cover flange 92a is formed on one side of the cover partition 94a, and the other upper cover flange 92a is formed on the other side of the cover partition 94a. The upper cover flanges 92a, 92a are integrally formed on the upper end of the second hollow cylinder 91, and protrude radially in a direction parallel to the XY plane.

[0046] A lead insertion passage 95 is formed between the cover partition portion 94a and the cover upper flange portion 92a formed on one side thereof, and a lead insertion passage 96 is formed between the cover partition portion 94a and the cover upper flange portion 92a formed on the other side thereof. The second lead portion 38a of the second wire 38 can be inserted into the lead insertion passage 95, and the second lead portion 38b of the second wire 38 can be inserted into the lead insertion passage 96.

[0047] The upper surface of the cover upper flange 92a is formed with a plurality of upward protrusions 97. The upward protrusions 97 are intended to form a gap between the cover upper flange 92a and the bottom surface of the seat 25a of the bobbin 20 (or the bottom surface of the bobbin upper flange 24) when the bobbin covers 90a, 90b are fixed to the bobbin 20 as shown in FIG.

[0048] 4, a pair of engagement portions 98, 98 are formed at the ends of each of the pair of upper cover flanges 92a, 92a. Each of the engagement portions 98, 98 is formed as a protrusion or a recess, and is configured to be able to engage with engagement portions 98, 98 formed at both ends of the upper cover flange 92b of the bobbin cover 90b.

[0049] A cover lower flange 93 is formed at the lower part of the second hollow cylinder 91. The cover lower flange 93 is integrally formed at the lower end part of the second hollow cylinder 91, and protrudes in the radial direction in a direction parallel to the XY plane.

[0050] 5, a second wire-fixing portion 99 is formed on the outer circumferential surface of the second hollow cylinder portion 91. The second wire-fixing portion 99 is formed at a position spaced upward from the cover lower flange portion 93 by approximately the width of one wire of the second wire 38. The second wire-fixing portion 99 protrudes outward from the outer circumferential surface of the second hollow cylinder portion 91. The second wire-fixing portion 99 has a thin plate shape, but the shape is not particularly limited.

[0051] The second wire-fixing portion 99 has a function similar to that of the first wire-fixing portion 27 (FIG. 4) formed on the outer circumferential surface of the first hollow cylinder portion 23. That is, the second lead portion 38b of the second wire 38 can be hooked and fixed to the second wire-fixing portion 99. The second wire 38 can be inserted into the gap between the second wire-fixing portion 99 and the cover lower flange portion 93.

[0052] 4, the configurations of the cover upper flange 92b and the cover partition 94b in the bobbin cover 90b are different from the configurations of the cover upper flanges 92a, 92a and the cover partition 94a in the bobbin cover 90a. More specifically, the cover upper flange 92b is formed continuously along the outer periphery of the upper part of the second hollow cylinder 91.

[0053] The cover partition portion 94b is formed so as to protrude upward from the upper surface of the cover upper flange portion 92b. The cover partition portion 94b has a predetermined length in the Y-axis direction, and its upper end portion is fitted into the fitting groove 29 of the base 25b.

[0054] 6, the second wire 38 is wound around the outer circumferential surface of the second hollow cylinder 91 of the bobbin covers 90a, 90b. More specifically, the second wire 38 is wound in a plurality of turns around the outer circumferential surface of the second hollow cylinder 91 above the second wire fixing portion 99, and is wound in one turn around the outer circumferential surface of the second hollow cylinder 91 below the second wire fixing portion 99 (at the lower end of the second hollow cylinder 91). As a result, the second coil portion 32 formed by winding the second wire 38 around the outer circumferential surface of the second hollow cylinder 91 is formed.

[0055] The second lead portion 38b of the second wire 38 rises from a position below the second wire fixing portion 99 toward the pedestal 25a. More specifically, the second lead portion 38b rises upward while being hooked on the second wire fixing portion 99, and is guided from the outside to the inside of the pedestal 25a via the outer wall cutout portion 253a. The second lead portion 38b is guided further inward of the pedestal 25a via the bottom surface cutout portion 254a, and is pulled out to the outside in the X-axis direction while passing through the inside of the first insertion passage 256a in a state in which it is bent substantially vertically toward the positive direction of the X-axis.

[0056] Meanwhile, the second lead portion 38a rises from the upper end of the outer circumferential surface of the second hollow cylinder portion 91 toward the pedestal 25a. More specifically, the second lead portion 38a is guided from the outside to the inside of the pedestal 25a via the outer cutout portion 253b. The second lead portion 38a is guided further toward the inside of the pedestal 25a via the bottom cutout portion 254b, and is pulled out to the outside in the X-axis direction while passing through the inside of the second insertion passage 256b in a state in which it is bent substantially vertically toward the positive direction of the X-axis.

[0057] As shown in Fig. 4, a first wire 37 is wound around the outer circumferential surface of the first hollow cylinder 23, and as shown in Fig. 6, a second wire 38 is wound around the outer circumferential surface of the second hollow cylinder 91, thereby forming a double-structure coil section in which the first coil section 31 is disposed on the inside and the second coil section 32 is disposed on the outside, as shown in Fig. 7A. One of the first coil section 31 and the second coil section 32 constitutes a primary coil, and the other constitutes a secondary coil.

[0058] 4, a cap member 80a is attached to the base 25a, and a cap member 80b is attached to the base 25b. The cap members 80a and 80b have the same configuration, and therefore, the configuration of the cap member 80b will not be described below.

[0059] The cap member 80a has a top plate portion 81. A pair of inner side walls 82, 82 and an outer side wall 83 are formed on the sides of the top plate portion 81. The outer side wall 83 is formed at one end of the top plate portion 81 in the Y-axis direction, and the inner side walls 82, 82 are formed at the other end of the top plate portion 81 in the Y-axis direction.

[0060] The outer side walls 83 of the cap member 80a are disposed so as to overlap with the outer walls 252a to 252c of the pedestal 25a, and the outer side walls 83 of the cap member 80b are disposed so as to overlap with the outer walls 252a to 252c of the pedestal 25b.

[0061] The pair of inner side walls 82, 82 are disposed at a predetermined interval in the X-axis direction. An engagement recess 82a is formed in one inner side wall 82, and an engagement recess 82b is formed in the other inner side wall 82. The cap member 80a can be attached to the base 25a by engaging the engagement recess 82a with the engagement protrusion 257a shown in FIG. 3 and engaging the engagement recess 82b with the engagement protrusion 257b.

[0062] 2, partition covers 50, 50 are arranged on the outer sides of the bobbin covers 90a, 90b. One partition cover 50 is formed on one side of the bobbin covers 90a, 90b in the X-axis direction, and the other partition cover 50 is formed on the other side of the bobbin covers 90a, 90b in the X-axis direction.

[0063] The partition cover 50 has a cover body 52 and a pair of locking pieces 54, 54 formed on both ends of the cover body 52 in the Z-axis direction. The cover body 52 is curved so as to cover the periphery of the second coil portion 32 formed on the outer circumferential surface of the second hollow cylinder portion 91, 91 of the bobbin cover 90a, 90b. The locking piece 54 is bent inwardly in a substantially vertical direction from the cover body 52. ​​The pair of locking pieces 54, 54 are attached so as to sandwich the cover upper flange portions 92a, 92b formed on the upper end portions of the second hollow cylinder portions 91, 91 of the bobbin covers 90a, 90b and the cover lower flange portions 93, 93 formed on the lower end portions.

[0064] As shown in Fig. 7B, the insulating covers 103, 103 shown in Fig. 2 are arranged on the outside of the bobbin covers 90a, 90b. The insulating cover 103 has a cover body 104 and a folded-back portion 105. The cover body 104 is arranged along the inner surface of a side plate 64 of the case 60, which will be described later, and the folded-back portion 105 is configured to be able to engage with the upper end portion of the side plate 64. The insulating cover 103 is intended to prevent the second coil portion 32 formed on the outer circumferential surface of the second hollow cylinder portion 91 of the bobbin covers 90a, 90b from contacting the side plate 64.

[0065] 2, terminals 100, 100 are attached to the respective ends of the first lead portions 37a, 37b of the first wire 37. The first lead portions 37a, 37b are wrapped in an insulating wire cover 101. Similarly, terminals 100, 100 are attached to the respective ends of the second lead portions 38a, 38b of the second wire 38. The second lead portions 38a, 38b are wrapped in an insulating wire cover 101.

[0066] The core assembly 40 has an upper core 40a, 40a and a lower core 40b, 40b. The core assembly 40 constitutes a so-called vertical core, and the upper core 40a, 40a and the lower core 40b, 40b are configured to be able to be combined in the Z-axis direction. The material of each of the cores 40a, 40b can be a soft magnetic material such as metal or ferrite, but is not particularly limited.

[0067] The upper cores 40a, 40a are each composed of two split cores 42a, 42a having the same shape, and are split by a plane parallel to the YZ plane. When the upper cores 40a, 40a are combined in the X-axis direction, they have an E-shaped cross section (however, the cross section is parallel to the XZ plane), forming a so-called E-shaped core. Note that the upper cores 40a, 40a are not limited to E-shaped cores, and may be composed of, for example, a U-shaped core (preferably a core having an outer leg).

[0068] The lower cores 40b, 40b are each composed of two split cores 42b, 42b having the same shape, and are split by a plane parallel to the YZ plane. When the lower cores 40b, 40b are combined in the X-axis direction, they have an E-shaped cross section (however, the cross section is parallel to the XZ plane), constituting a so-called E-shaped core. Note that the lower cores 40b, 40b are not limited to E-shaped cores, and may be composed of, for example, a U-shaped core (preferably a core having an outer leg).

[0069] Each of the upper cores 40a has a base portion 44a extending in the X-axis direction, a middle leg portion 46a protruding in the Z-axis direction from one end of the base portion 44a in the X-axis direction, and an outer leg portion 48a protruding in the Z-axis direction from the other end. The upper cores 40a are assembled in the X-axis direction at the positions of the middle legs 46a. That is, the upper cores 40a in this embodiment are divided at the positions of the middle legs 46a, and are not divided at the positions of the outer legs 48a.

[0070] When the upper cores 40a, 40a are combined in the X-axis direction, the center legs 46a, 46a are disposed between the outer legs 48a, 48a of the upper cores 40a, 40a. The pair of center legs 46a, 46a are adapted to be inserted from above in the Z-axis direction into the through-hole of the first hollow cylinder portion 23 of the bobbin 20. In the following, the surfaces of the base portions 44a, 44a are referred to as base surfaces 440a, 440a.

[0071] Each of the lower cores 40b has a base portion 44b extending in the X-axis direction, a middle leg portion 46b protruding in the Z-axis direction from one end of the base portion 44b in the X-axis direction, and an outer leg portion 48b protruding in the Z-axis direction from the other end. The lower cores 40b are combined in the X-axis direction at the positions of the middle legs 46b. That is, the lower cores 40b in this embodiment are divided at the positions of the middle legs 46b, and are not divided at the positions of the outer legs 48b.

[0072] When the lower cores 40b, 40b are combined in the X-axis direction, the center legs 46b, 46b are disposed between the outer legs 48b, 48b of the lower cores 40b, 40b. The pair of center legs 46b, 46b are adapted to be inserted into the through hole of the first hollow cylinder portion 23 of the bobbin 20 from below in the Z-axis direction. Note that, hereinafter, the surfaces of the base portions 44b, 44b are referred to as base surfaces 440b, 440b.

[0073] The Z-axis direction ends of the outer legs 48a, 48a of the upper cores 40a, 40a and the outer legs 48b, 48b of the lower cores 40b, 40b are abutted against each other on the outside of the bobbin 20. The tips of the center legs 46a, 46a of the upper cores 40a, 40a and the center legs 46b, 46b of the lower cores 40b, 40b in the Z-axis direction are butted against each other inside the bobbin 20 in the Z-axis direction.

[0074] A pair of heat dissipation covers 70, 70 are attached to the core assembly 40. The heat dissipation cover 70 has a top cover 72 and a side cover 74. As shown in Fig. 1B, the top cover 72 is fixed to the base surface 440a of the base portion 44a, and the side cover 74 is fixed to the outer surfaces of the outer legs 48a, 48b so as to straddle the outer legs 48a, 48b.

[0075] As shown in Fig. 7A, at least a portion of the core assembly 40 is housed in the case 60. In the illustrated example, a portion of the upper cores 40a, 40a and all of the lower cores 40b, 40b are housed inside the case 60. Base surfaces 440b, 440b of the base portions 44b, 44b are placed on a bottom plate (bottom portion) 62 of the case 60 and become the mounting side surfaces for the lower cores 40b, 40b. The case 60 is made of a metal material with high thermal conductivity, such as aluminum, and functions as a heat dissipation case.

[0076] As shown in FIG. 8, the case 60 has a bottom plate 62 and a side plate 64. The side plate 64 extends upward and is formed on the periphery of the bottom plate 62. More specifically, the side plate 64 is formed on each side of the bottom plate 62, which is substantially rectangular when viewed from above, and has two faces parallel to the YZ plane and two faces substantially parallel to the XZ plane. A bulge 66 is formed on each of the two faces of the side plate 64 substantially parallel to the XZ plane. The bulge 66 is formed of a portion that bulges outward in the Y-axis direction, and a recess is formed inside the case 60 at the position where the bulge 66 is formed. A part of the second coil portion 32 shown in FIG. 6 is disposed inside this recess.

[0077] 7A and 8, in this embodiment, a plurality of (eight in the illustrated example) support portions 622 are integrally formed on the bottom plate 62. The lower cores 44b, 44b are placed on the support portions 622. In this embodiment, the support portions 622 are made of convex portions (projections) protruding from an upper surface 620 of the bottom plate 62.

[0078] When viewed from above, the shape of the support part 622 is circular. However, the shape of the support part 622 is not limited to this, and may be, for example, elliptical, polygonal, or other shapes. The diameter of the support part 622 is preferably 2 to 5 mm.

[0079] In the illustrated example, a tapered surface 622a is formed on the support portion 622. The shape of the tip portion (tip surface) of the support portion 622 may be flat or pointed. Also, the support portion 622 may be in surface contact or point contact with the base surfaces 440b, 440b.

[0080] Each of the multiple support parts 622 is formed discretely (locally) on the upper surface 620 of the bottom plate 62. The number of support parts 622 is not particularly limited, but is preferably two or more, and more preferably three or more. In this case, the lower cores 40b, 40b can be placed on the multiple support parts 622 in a stably state.

[0081] The positions where the support parts 622 are formed (the arrangement pattern or the pitch between the support parts 622, etc.) are not particularly limited and may be changed as appropriate. For example, by forming each of the multiple support parts 622 at least at the four corners of the bottom plate 62, the stability when the lower cores 40b, 40b are placed on the multiple support parts 622 can be improved.

[0082] In the illustrated example, three support parts 622 are arranged linearly along the Y-axis direction on one side of the bottom plate 62 in the X-axis direction. Also, three support parts 622 are arranged linearly along the Y-axis direction on the other side of the bottom plate 62 in the X-axis direction. Furthermore, two support parts 622 are arranged along the X-axis direction at approximately the center of the bottom plate 62 in the Y-axis direction. Focusing on approximately the center of the bottom plate 62 in the Y-axis direction, four support parts 622 are arranged linearly along the X-axis direction.

[0083] The support portion 622 supports the base surfaces 440b, 440b (the mounting side surfaces of the lower cores 40b, 40b) of the lower cores 40b, 40b at a position spaced upward from the upper surface 620 of the bottom plate 62. In this embodiment, the base surfaces 440b, 440b of the lower cores 40b, 40b are placed at a position different from the upper surface 620 of the bottom plate 62, and are placed above the upper surface 620 by the protruding length of the support portion 622.

[0084] The upward protruding length of the support portion 622 is preferably 0.05 to 1.5 mm, and more preferably 0.1 to 1.0 mm. In the illustrated example, the protruding length of the support portion 622 is smaller than the plate thickness of the bottom plate 62, but it may be equal to or larger than the plate thickness of the bottom plate 62. The ratio L1 / T1 of the protruding length L1 of the support portion 622 to the plate thickness T1 of the bottom plate 62 is preferably 1 / 4 to 2, and more preferably 1 / 2 to 1. The plate thickness of the bottom plate 62 is preferably 0.5 to 2.0 mm, and more preferably 1.0 to 1.5 mm.

[0085] In this embodiment, since a plurality of support portions 622 are formed on the upper surface 620 of the bottom plate 62, when the lower cores 40b, 40b (base portions 44b, 44b) are placed on the upper surface 620, the base surfaces 440b, 440b locally (partially) abut (join) against the bottom plate 62. Therefore, in this embodiment, the contact area between the bottom plate 62 and the base surfaces 440b, 440b is extremely small, and the area of ​​the portions of the base surfaces 440b, 440b that are in contact with the bottom plate 62 (i.e., the sum of the contact areas between each of the plurality of support portions 622 and the bottom plate 62) is smaller than the area of ​​the portions that are not in contact with the bottom plate 62.

[0086] The ratio S1 / S2 of the contact area S1 between the base surfaces 440b, 440b and the bottom plate 62 (the sum of the contact areas S1 between the base surfaces 440b, 440b and each of the multiple support portions 622) and the surface area S2 of the base surfaces 440b, 440b is preferably 50% or less, more preferably 30% or less, and particularly preferably 10% or less. In other words, the ratio S1 / S2 is the proportion of the surface area of ​​the portions of the base surfaces 440b, 440b that are in contact with the bottom plate 62 among the surface areas of the base surfaces 440b, 440b.

[0087] A gap 624 is formed between the upper surface 620 of the bottom plate 62 and the base surfaces 440b, 440b. The width of the gap 624 in the Z-axis direction is approximately equal to the protruding length of the support portion 622 in the Z-axis direction. The gap 624 is filled with resin 107. The resin 107 is a heat dissipating resin having high thermal conductivity, and is made of a potting resin.

[0088] In this embodiment, the resin 107 is filled between the upper surface 620 of the bottom plate 62 and the base surfaces 440b, 440b, in addition to between the side of the core assembly 40 and the side plate 64 of the case 60. The resin 107 is filled inside the gap 624, and is disposed inside the gap 624 in a hardened state. The thickness of the resin 107 in the Z-axis direction is equal to the width of the gap 624 in the Z-axis direction. In this way, the coil device 10 in this embodiment is provided with a configuration in which the base surfaces 440b, 440b are in partial contact with the bottom plate 62, and the base surfaces 440b, 440b are partially connected to the bottom plate 62 via the resin 107.

[0089] A recess 623 is formed in the lower surface 621 of the bottom plate 62 in a position corresponding to the position of the support portion 622. The recess 623 is formed for processing reasons when forming a protrusion (support portion 622) on the upper surface 620 of the bottom plate 62. Note that the recess 623 may be omitted, and the lower surface 621 of the bottom plate 62 may be configured as a flat surface. Also, the heat dissipation property of the bottom plate 62 may be improved by filling (accommodating) a highly thermally conductive material or the like inside the recess 623.

[0090] Two bosses 68, 68 are formed at the corners of the bottom plate 62. An opening (e.g., a bolt hole) is formed in the boss 68, and by fixing a fastener or the like to this opening, it is possible to fix the case 60 to, for example, a cooling mechanism.

[0091] In manufacturing the coil device 10, first, the components shown in Fig. 2 are prepared. Next, as shown in Fig. 4, the first wire 37 is wound around the outer circumferential surface of the first hollow cylinder 23 of the bobbin 20 to form the first coil portion 31. In addition, the first lead portion 37b of the first wire 37 is pulled out from the lower end of the first hollow cylinder 23 toward the base 25b while being hooked on the first wire fixing portion 27. At this time, the first lead portion 37b is pulled out to the position of the second insertion passage 256b through the outer wall cutout portion 253b and the bottom surface cutout portion 254b, and is pulled out to the outside in the X-axis direction through the second insertion passage 256b.

[0092] Additionally, the first lead portion 37a of the first wire 37 is drawn out toward the base 25b from the upper end portion of the first hollow cylinder portion 23. At this time, the first lead portion 37a is drawn out to the position of the first insertion passage 256a through the outer wall cutout portion 253a and the bottom surface cutout portion 254a, and is drawn outward in the X-axis direction through the first insertion passage 256a.

[0093] Next, as shown in Fig. 5, bobbin covers 90a, 90b are attached to the bobbin 20 so as to cover the periphery of the first coil portion 31, and as shown in Fig. 6, the second wire 38 is wound around the outer circumferential surface of the second hollow cylinder portion 91 to form the second coil portion 32. Next, the second lead portion 38b of the second wire 38 is pulled out from the lower end portion of the second hollow cylinder portion 91 toward the base 25a while being hooked on the second wire fixing portion 99. At this time, the second lead portion 38b is pulled out to the position of the first insertion passage 256a through the outer wall notch portion 253a and the bottom surface notch portion 254a, and is pulled out to the outside in the X-axis direction through the first insertion passage 256a.

[0094] Additionally, the second lead portion 38a of the second wire 38 is drawn out toward the pedestal 25a from the upper end portion of the second hollow cylinder portion 91. At this time, the second lead portion 38a is drawn out to the position of the second insertion passage 256b through the outer wall cutout portion 253b and the bottom surface cutout portion 254b, and then drawn outward in the X-axis direction through the second insertion passage 256b.

[0095] 2 are attached to the bobbin covers 90a, 90b in the manner shown in FIG. 7A so as to cover the periphery of the second coil portion 32, and the separating plate portion 106 is attached to the separating plate fixing portion 28.

[0096] Next, the upper core 40a, 40a is attached to the bobbin 20 while the middle leg portions 46a, 46a are inserted from above into the through hole of the first hollow cylinder portion 23, and the lower core 40b, 40b is attached to the bobbin 20 while the middle leg portions 46b, 46b are inserted from below into the through hole of the first hollow cylinder portion 23, thereby forming the core assembly 40.

[0097] Before and after that, cap members 80a, 80b shown in Fig. 4 are attached to the pedestals 25a, 25b, and heat dissipation covers 70, 70 shown in Fig. 2 are attached to the core assembly 40 in the manner shown in Fig. 1B. In addition, blocks 102, 102 shown in Fig. 2 are fixed inside the recessed portions 22a, 22a of the legs 22, 22 of the bobbin 20 (Fig. 5).

[0098] Next, the bobbin 20 to which the core assembly 40 and the like are attached is housed inside the case 60, and the insulating covers 103, 103 are engaged with the upper end of the side plate 64 of the case 60 in a manner as shown in FIG. 7B. When the bobbin 20 is housed inside the case 60, the base parts 44b, 44b are placed on the support parts 622 formed on the upper surface 620 of the bottom plate 62. As a result, a gap 624 is formed between the upper surface 620 of the bottom plate 62 and the base surfaces 440b, 440b. Next, the resin 107 is injected inside the case 60, and the resin 107 is filled in the gap 624, and the resin 107 is also filled in the gap between the side part of the core assembly 40 and the side plate 64. In this manner, the coil device 10 shown in FIG. 1A is obtained. If necessary, the terminals 100 and the wire covers 101 are attached to the first lead parts 37a, 37b and the second lead parts 38a, 38b.

[0099] As described above, in the coil device 10 according to this embodiment, the lower cores 40b are placed on the case 60, and the support parts 622 are provided to support the base surfaces 440b (placement side surfaces) of the lower cores 40b at positions spaced apart from the upper surface 620 of the bottom plate 62 of the case 60. Therefore, the base surfaces 440b are floating above the upper surface 620 of the bottom plate 62 at positions other than the positions where the support parts 622 are provided, and the entire base surfaces 440b are not in contact with the upper surface 620 of the bottom plate 62. Therefore, compared to the conventional technology, it is possible to reduce the contact area between the base surfaces 440b, 440b and the bottom plate 62, thereby reducing the stress on the lower cores 40b, 40b caused by the difference in thermal expansion coefficient between the two, and preventing cracks from occurring in the lower cores 40b, 40b (especially near the bases of the outer leg portions 48b, 48b at the base portions 44b, 44b).

[0100] Furthermore, at the position where the support portion 622 is provided, heat generated in the core assembly 40 and the like can be propagated to the bottom plate 62 via the support portion 622, and the heat can be dissipated via the bottom plate 62. Furthermore, at positions other than the position where the support portion 622 is provided, the base surfaces 440b, 440b are disposed at a position spaced apart from the upper surface 620 of the bottom plate 62 by the height of the support portion 622, and a gap 624 is formed between the base surfaces 440b, 440b and the upper surface 620 of the bottom plate 62. By filling the gap 624 with the resin 107 as in this embodiment, the heat generated in the core assembly 40 and the like can be dissipated via the resin 107 and the bottom plate 62. As described above, according to this embodiment, it is possible to realize a coil device 10 that has excellent heat dissipation properties and is capable of preventing damage to the lower cores 40b, 40b.

[0101] 8 on the upper surface 620 of the bottom plate 62, the stress applied to the lower cores 40b, 40b (particularly near the roots of the outer legs 48b, 48b on the bases 44b, 44b) was reduced to half or less than that in the case where the plurality of support parts 622 was not formed. Also, even if the plurality of support parts 622 was formed on the upper surface 620 of the bottom plate 62 and the contact area between the base surfaces 440b, 440b (mounting side surfaces) of the lower cores 40b, 40b and the bottom plate 62 was reduced, the heat dissipation of the coil device 10 via the case 60 changed by only less than 1% compared to the case where the plurality of support parts 622 was not formed, and it was confirmed that good heat dissipation was obtained.

[0102] In this embodiment, the case 60 (upper surface 620 of the bottom plate 62) is provided with a plurality of support parts 622. Therefore, the base surfaces 440b, 440b can be supported in a stable state by the plurality of support parts 622. In addition, heat generated in the core assembly 40 and the like can be efficiently transmitted to the bottom plate 62 (parts of the bottom plate 62 where the support parts 622 are not formed (the bottom plate main body part)) via the plurality of support parts 622, and the heat can be effectively dissipated via the bottom plate 62.

[0103] In this embodiment, the support portion 622 is a protrusion protruding from the upper surface 620 of the bottom plate 62. This allows the contact area between the base surfaces 440b, 440b and the bottom plate 62 to be sufficiently small, effectively reducing the stress on the lower cores 40b, 40b caused by the difference in thermal expansion coefficient between the base surfaces 440b, 440b and the bottom plate 62. Furthermore, by integrally forming the support portion 622 with the bottom plate 62, it is possible to efficiently transmit heat generated in the core assembly 40, etc. to the bottom plate 62 via the support portion 622, and the heat can be effectively dissipated via the bottom plate 62.

[0104] Furthermore, by making the lower surface 621 of the bottom plate 62 of the case 60 a flat surface, it is possible to increase the surface area of ​​the contact surface between the lower surface 621 of the bottom plate 62 and the cooling mechanism provided below it, and heat generated in the core assembly 40, etc. can be effectively dissipated via the bottom plate 62.

[0105] Second embodiment The coil device 110 according to the second embodiment of the present invention differs only in the following respects, and the other configurations are the same as those of the first embodiment described above, and the coil device 110 provides the same effects and advantages. In the drawings, the same reference numerals are used to designate the same components as those of the first embodiment, and descriptions of the overlapping parts are omitted.

[0106] As shown in Fig. 9, the coil device 110 has a core assembly 140 and a case 160. As shown in Fig. 10, the case 160 has a bottom plate 162, which differs from the bottom plate 62 in the first embodiment in that an upper surface 620 of the bottom plate 162 is a flat surface.

[0107] The core assembly 140 has an upper core 140a, 140a and a lower core 140b, 140b. The upper core 140a, 140a has a base portion 144a, 144a, and the base portion 144a, 144a is different from the base portion 44a, 44a in the first embodiment in that a plurality of (eight in the example shown in FIG. 9) abutment portions 441 are integrally formed on the base surface 440a, 440a. Similarly, the lower core 140b, 140b has a base portion 144b, 144b, and the base portion 144b, 144b is different from the base portion 44b, 44b in the first embodiment in that a plurality of (eight) abutment portions 441 are integrally formed on the base surface 440b, 440b. The configuration of the abutment portions 441 formed on the base surfaces 440a, 440a is similar to the configuration of the abutment portions 441 formed on the base surfaces 440b, 440b, and the following description will focus on the configuration of the latter abutment portion 441.

[0108] The contact portion 441 in this embodiment is a convex portion (projection portion) projecting from the base surfaces 440b, 440b of the base portions 144b, 144b. The shape and size of the contact portion 441 are similar to the shape and size of the support portion 622 in the first embodiment. Therefore, the above-mentioned numerical range regarding the size of the support portion 622 also applies to the contact portion 441.

[0109] Each of the multiple contact portions 441 is formed discretely (locally) on the base surfaces 440b. The number of contact portions 441 is not particularly limited, but is preferably two or more, and more preferably three or more. In this case, the lower cores 140b can be stably placed on the upper surface 620 of the case 160. The number of contact portions 441 formed on each of the base surfaces 440b may be different.

[0110] The formation positions of the abutment parts 441 (arrangement pattern or pitch between the abutment parts 441, etc.) are not particularly limited and may be changed as appropriate. In the example shown in FIG. 9, on one side in the X-axis direction of the base surface 440a of one upper core 140a, three abutment parts 441 are arranged linearly along the Y-axis direction. Also, on the other side in the X-axis direction of the base surface 440a, one abutment part 441 is arranged approximately at the center in the Y-axis direction. Also, on one side in the X-axis direction of the base surface 440a of the other upper core 140a, one abutment part 441 is arranged approximately at the center in the Y-axis direction. Also, on the other side in the X-axis direction of the base surface 440a, three abutment parts 441 are arranged linearly along the Y-axis direction. Focusing on the approximately center in the Y-axis direction of the base surfaces 440a, 440a, four abutment parts 441 are arranged linearly along the X-axis direction.

[0111] The contact portion 441 contacts the upper surface 620 of the bottom plate 162 of the case 160 at a position spaced downward from the base surfaces 440b (the mounting sides of the lower cores 40b). In this embodiment, the base surfaces 440b of the lower cores 140b are disposed at positions different from the upper surface 620 of the bottom plate 162, and are disposed above the upper surface 620 by the protruding length of the contact portion 441.

[0112] In this embodiment, since a plurality of contact portions 441 are formed on the base surfaces 440b, when the lower cores 140b are placed on the upper surface 620 of the bottom plate 162, the lower cores 140b (base portions 144b) locally (partially) contact (join) the bottom plate 162. Therefore, in this embodiment, the contact area between the bottom plate 162 and the lower cores 140b is extremely small, and the area of ​​the portions of the lower cores 140b that are in contact with the bottom plate 162 (i.e., the sum of the contact areas between each of the plurality of contact portions 441 and the bottom plate 162) is smaller than the area of ​​the portions that are not in contact with the bottom plate 162.

[0113] The ratio S1 / S2 of the contact area S1 between the lower core 140b, 140b (base portion 144b, 144b) and the bottom plate 162 (the sum of the contact areas between each of the multiple abutment portions 441 and the upper surface 620 of the bottom plate 162) to the surface area S2 of the base surfaces 440b, 440b (assuming that the abutment portions 441 are not formed on the base surfaces 440b, 440b) is preferably 50% or less, more preferably 30% or less, and particularly preferably 10% or less.

[0114] A gap 624 is formed between the upper surface 620 of the bottom plate 162 and the base surfaces 440b, 440b. The width of the gap 624 in the Z-axis direction is approximately equal to the protruding length of the contact portion 441 in the Z-axis direction. The gap 624 is filled with resin 107. The coil device 110 in this embodiment is provided with a configuration in which the lower cores 140b, 140b are in partial contact with the bottom plate 162, and the base surfaces 440b, 440b are partially connected to the bottom plate 162 via the resin 107.

[0115] In the coil device 110 of this embodiment, the base surfaces 440b, 440b (mounting side surfaces) of the lower cores 140b, 140b are formed with abutment parts 441 that abut against the bottom part 162 of the case 160 at a position separated from the base surfaces 440b, 440b. The abutment parts 441 perform the same function as the above-mentioned support parts 622, and mainly form a gap 624 between the base surfaces 440b, 440b and the upper surface 620 of the bottom plate 162 at positions other than the positions where the abutment parts 441 are formed, so that the entirety of the base surfaces 440b, 440b does not contact the upper surface 620 of the bottom plate 162. That is, the coil device 110 of this embodiment is different from the coil device 10 of the first embodiment in that the mechanism for performing the above-mentioned function is provided not on the case 160 side but on the lower cores 140b, 140b side.

[0116] Therefore, in the coil device 110 of this embodiment, the contact area between the lower cores 140b, 140b and the bottom 162 is reduced, and the stress acting on the lower cores 140b, 140b due to the difference in thermal expansion coefficient between the two is reduced, so that it is possible to prevent cracks from occurring in the lower cores 140b, 140b (particularly near the roots of the outer legs 48b, 48b in the base parts 144b, 144b). In addition, in a position other than the position where the abutment part 441 is formed, for example, by filling the gap 624 with resin 107, heat generated in the core assembly 140, etc. can be effectively dissipated through the resin 107 and the bottom 162. In addition, in the position where the abutment part 441 is formed, the heat can be propagated to the bottom through the abutment part 441 and dissipated.

[0117] In this embodiment, the base surfaces 440b, 440b are each formed with a plurality of abutment portions 441. In this case, the abutment portions 441 function as legs for placing the lower cores 140b, 140b on the upper surface 620 of the bottom portion 162, and the lower cores 140b, 140b can be placed in a stable state on the upper surface 620 of the bottom portion 162 via the plurality of abutment portions 441. In addition, heat generated in the core assembly 140, etc. can be efficiently propagated to the bottom portion 162 via the plurality of abutment portions 441, and the heat can be effectively dissipated via the bottom portion 162.

[0118] In this embodiment, the contact portion 441 is a protrusion protruding from the base surface 440b. This allows the contact area between the lower core 140b and the bottom portion 162 to be sufficiently small, effectively reducing stress acting on the lower core 140b (particularly near the root of the outer leg portion 48b on the base portion 144b) due to the difference in thermal expansion coefficient between the two.

[0119] Third embodiment The coil device 210 according to the third embodiment of the present invention differs only in the following points, and the other configurations are the same as those of the first embodiment described above, and the coil device 210 provides the same effects and advantages. In the drawings, the same reference numerals are used to designate the same components as those of the first embodiment, and descriptions of the overlapping parts are omitted.

[0120] As shown in Fig. 11, the coil device 210 has a case 260. As shown in Fig. 12, the case 260 is configured to be separable into a bottom plate 262 and a side plate 264, which are combined to form one case.

[0121] The side plate 264 differs from the side plate 64 in the first embodiment in that it has an edge portion 640. The edge portion 640 is formed on one side and the other side of the side plate 264 in the X-axis direction, and is integrally formed at the lower end of the side plate 264. The edge portion 640 has a surface parallel to the XY plane and is substantially C-shaped. The edge portion 640 has a predetermined width (width in a direction perpendicular to the extending direction) along its extending direction. In the following, the side portion on one side of the side plate 264 in the Y-axis direction is referred to as a first side portion 64a, the side portion on one side of the X-axis direction is referred to as a second side portion 64b, the side portion on the other side of the Y-axis direction is referred to as a third side portion 64c, and the side portion on the other side of the X-axis direction is referred to as a fourth side portion 64d.

[0122] The edge 640 located on one side in the X-axis direction has a portion extending parallel to the first side 64a, a portion extending parallel to the second side 64b, and a portion extending parallel to the third side 64c. The edge 640 located on the other side in the X-axis direction has a portion extending parallel to the third side 64c, a portion extending parallel to the fourth side 64d, and a portion extending parallel to the first side 64a.

[0123] The bottom plate 262 has a bulging bottom portion 625. The bulging bottom portion 625 is formed on one side and the other side in the Y-axis direction of the bottom plate 262. The bulging bottom portion 625 is formed at a position corresponding to the bulging portion 66 formed on the side plate 264.

[0124] The bottom plate 262 is assembled to the side plate 264 while being aligned so that one end of the bottom plate 262 in the X-axis direction overlaps with an edge portion 640 on one side of the side plate 264 in the X-axis direction. The bottom plate 262 is assembled to the side plate 264 so that the other end of the bottom plate 262 in the X-axis direction overlaps with an edge portion 640 on the other side of the side plate 264 in the X-axis direction. At this time, each edge portion 640 is disposed on the upper surface 620 of the bottom plate 62. Therefore, as shown in FIG. 13, overlapping portions 69, 69 are formed at each overlapping portion between the bottom plate 262 and each edge portion 640.

[0125] The lower cores 40b (base portions 44b) are placed on the overlapping portions 69, and a gap 624 is formed between the base surfaces 440b of the lower cores 40b and the bottom plate 262. That is, the overlapping portions 69 function as supporting portions that support the base surfaces 440b of the base portions 44b at positions spaced apart from the upper surface 620 of the bottom plate 262. The gap 624 is filled with resin 107.

[0126] The overlapping portions 69, 69 (support portions) in this embodiment are formed as separate bodies from the bottom plate 262, and constitute part of the side plate 264. In this manner, the function of the support portion does not necessarily have to be provided in the bottom plate 262, but may be provided in any part of the case 260. The upper surfaces of the overlapping portions 69, 69 in this embodiment are flat, allowing the overlapping portions 69, 69 to come into surface contact with the base surfaces 440b, 440b.

[0127] In this embodiment, the case 260 is configured to be separable into a side plate 264 and a bottom plate 262. Therefore, by simply combining the side plate 264 and the bottom plate 262, overlapping portions 69, 69 (support portions) can be easily formed at the combined position of the side plate 264 and the bottom plate 262.

[0128] In this embodiment, the overlapping portions 69, 69 are formed as separate bodies from the bottom plate 262. In this case, since there is no need to form a support portion on the bottom plate 262, it becomes possible to configure the upper surface 620 of the bottom plate 262 in a flat shape, and the manufacture of the case 260 becomes easier.

[0129] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, in the first embodiment, the bottom plate 62 is formed with a plurality of support portions 622, but the number of support portions 622 may be one. In the second embodiment, the base surfaces 440b, 440b are formed with a plurality of abutment portions 441, but the number of abutment portions 441 may be one. In this case, the abutment portion 441 may be formed on only one of the base surfaces 440b, 440b.

[0130] In the first embodiment, the support portion 622 is configured as a protrusion, but the shape is not particularly limited, and may be formed in a stripe shape, for example. Alternatively, the support portion 622 may have a bent or curved shape, or may be configured in any shape. The same applies to the contact portion 441 in the second embodiment.

[0131] In the first embodiment, the bottom plate 62 and the side plate 64 are both made of metal, but the side plate 64 may be made of, for example, a resin molded body. The same applies to the second and third embodiments.

[0132] In the second embodiment, the contact portions 441 are formed on the base surfaces 440a, 440a of the upper cores 140a, 140a, but they may be omitted.

[0133] The first embodiment may be combined with the third embodiment, and the case 60 may be configured to be separable into a bottom plate 62 and a side plate 64. The second embodiment may be combined with the third embodiment, and the case 160 may be configured to be separable into a bottom plate 162 and a side plate 64.

[0134] In each of the above embodiments, the core assembly 40 is formed by combining E-shaped cores, but it may also be formed by combining U-shaped cores, or a combination of an E-shaped core and an I-shaped core.

[0135] In each of the above embodiments, the application of the present invention to a transformer has been shown, but the present invention may also be applied to other coil devices. [Explanation of symbols]

[0136] 10, 110, 120... Coil device 20…Bobbin 31…First coil section 32…Second coil section 40,140...Core assembly 40a, 140a...Upper core 40b, 140b…Lower core 42a, 42b...Split core 44a, 44b, 144a, 144b...Base part 440a, 440b...Base surface 441...Abutting part 46a,46b...middle leg 48a, 48b…Outer leg 50…Partition cover 60, 160, 260…case 62,162,262…bottom plate 620…Top surface 621…Bottom surface 622...Support part 622a...Tapered surface 623…Recess 624…Gap 625...Bulging bottom 64,264…Side plate 64a to 64d: First side to fourth side 640…Edge 66…bulge 68…Boss section 69…Duplicate section

Claims

1. A core, A case in which at least a portion of the core is housed, The case is provided with a support portion on which the core is placed and which supports a side surface of the core at a position spaced apart from an upper surface of a bottom portion of the case, The case includes a plurality of support portions disposed therein, The diameter of the support portion is 2 to 5 mm, The mounting side surface of the core and the support portion are in contact with each other without being bonded to each other, A gap corresponding to the protruding length of each of the support parts is formed between the upper surface of the bottom of the case and the side surface on which the core is mounted, and the gap is filled with a heat dissipating resin.

2. the core is split along a plane perpendicular to the bottom of the case, The coil device according to claim 1 , wherein each of the plurality of support portions is disposed on a lower surface of the divided core.

3. The coil device according to claim 1 or 2, wherein the support portion is formed on the bottom portion and comprises a first protrusion protruding from an upper surface of the bottom portion.

4. 4. The coil device according to claim 1, wherein the lower surface of the bottom of the case is a flat surface.

5. 3. The coil device according to claim 1, wherein the case is configured so as to be separable into a side plate and the bottom portion of the case.

6. The coil device according to claim 5 , wherein the support portion is formed as a separate body from the bottom portion.

7. A core, A case in which the core is placed and in which at least a portion of the core is housed, A coil device in which an abutment portion is formed on the mounting side of the core, the abutting against the bottom of the case at a position spaced from the mounting side of the core without being bonded to the bottom of the case.

8. The coil device according to claim 7 , wherein a plurality of the contact portions are formed on the mounting side surface of the core.

9. The coil device according to claim 7 or 8, wherein the abutting portion is formed of a second protrusion protruding from the mounting side surface of the core.

10. 10. The coil device according to claim 1, wherein the heat dissipating resin is filled between the mounting side surface of the core and the bottom portion.

Images