Coil arrangement

Abstract

Provided is a coil device capable of effectively preventing breakage of a core. A coil device (10) has: upper cores (40a, 40a) and lower cores (40b, 40b) arranged along a Z-axis direction and joined to each other via a joining resin (200); and a bottom plate (62) of a housing (60) that contacts the lower cores (40b, 40b) on the opposite side of the joining portions of the upper cores (40a, 40a) and the lower cores (40b, 40b) along a plane perpendicular to the Z-axis direction. The Young's modulus of the joining resin (200) is 90 MPa or less.

Description

Technical Field

[0001] This invention relates to coil devices. Background Technology

[0002] As a technique for improving the heat dissipation of a coil device, the technique disclosed in Patent Document 1 is known, for example. The coil device disclosed in Patent Document 1 has: an upper core and a lower core arranged vertically; and a housing for housing the upper core and the lower core. The bottom plate of the housing is fixed to a pedestal having a cooling mechanism, and the heat of the upper core and the lower core can be dissipated by transferring the heat of the upper core and the lower core to the pedestal through the bottom plate of the housing.

[0003] In such coil devices, the upper and lower cores are securely joined and housed inside the casing. However, in a coil device like the one disclosed in Patent Document 1, where only the lower core abuts against the bottom plate of the casing, a difference in heat dissipation occurs between the upper and lower cores, resulting in a temperature difference. Consequently, due to this temperature difference, the upper core shifts, and the lower core shifts in a manner that follows the shift of the upper core. This applies excessive stress to the lower core, potentially causing cracks to form in a portion of it.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-36194 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] The present invention was made in view of the above circumstances, and its object is to provide a coil device that can effectively prevent core breakage.

[0009] Means for solving technical problems

[0010] To achieve the above objectives, the coil device of the present invention comprises: a first core and a second core arranged along a first axial direction and joined to each other by a bonding resin; and a plate-shaped member that contacts the second core along a surface perpendicular to the first axial direction on the opposite side of the joint between the first core and the second core, wherein the bonding resin has a Young's modulus of 90 MPa or less.

[0011] The coil device of the present invention comprises: a first core and a second core arranged along a first axial direction and joined to each other by a bonding resin; and a plate-shaped member that contacts the second core along a plane perpendicular to the first axial direction on the opposite side of the joint between the first core and the second core. Therefore, when the plate-shaped member is directly or indirectly fixed to, for example, a cooling mechanism, the second core, which is in contact with the plate-shaped member, is cooled more efficiently than the first core, resulting in a temperature difference between the first and second cores. As a result, the temperature of the first core becomes higher than that of the second core, and the displacement of the first core becomes greater than that of the second core. Even in this state, in the coil device of the present invention, the bonding resin used to join the first and second cores has a Young's modulus of 90 MPa or less, and the bonding resin is flexible; therefore, the first core and the second core are mechanically joined weakly, and the displacement of the first core does not easily affect the second core. Therefore, it is possible to prevent the second core from displacing in a manner that follows the displacement of the first core, to prevent excessive stress from being applied to the second core, and to effectively prevent cracks from forming in a portion of the second core. Therefore, by employing the coil device of the present invention, a coil device that can effectively prevent core breakage can be realized.

[0012] Furthermore, the first core and the second core are thermally connected by a bonding resin, and the heat from the first core can be effectively transferred to the plate-shaped component through the second core. Therefore, the heat dissipation of the first core and the second core can be maintained in a good state.

[0013] Preferably, the glass transition temperature of the bonding resin is below 0°C. With this approach, the bonding resin remains in a soft rubber state even at lower temperatures (e.g., 0°C to room temperature). Therefore, by using such a bonding resin to bond the first core and the second core, the first core and the second core are mechanically bonded relatively weakly, and core breakage can be effectively prevented even if a temperature difference exists between the first core and the second core.

[0014] Alternatively, the plate-like component may form part of a housing for receiving the first and second cores. By employing this design, heat from the first and second cores can be dissipated through various parts of the housing, thus further improving the heat dissipation performance of the coil assembly.

[0015] Preferably, the interior of the housing is filled with potting resin. By adopting this approach, the heat from the first core, the second core, etc., can be transferred to the housing via the potting resin, allowing this heat to be dissipated effectively.

[0016] Preferably, the upper surface of the potting resin filling the interior of the housing is located above the junction of the first core and the second core within the housing. By employing this arrangement, not only is the second core covered by the potting resin inside the housing, but at least a portion of the first core is also covered by the potting resin, thus enabling efficient heat dissipation from both the first and second cores via the potting resin.

[0017] Alternatively, the Young's modulus of the potting resin may be below 10 MPa.

[0018] Preferably, the Young's modulus of the bonding resin is greater than that of the potting resin. By adopting this approach, core breakage can be effectively prevented as described above, and the first and second cores can be bonded together with good bonding strength via the bonding resin.

[0019] Alternatively, at least one of the first core and the second core may have an outer pair of legs and a middle leg formed between the pair of outer legs. At the position of the pair of outer legs, the first core and the second core are joined via the bonding resin; at the position of the middle leg, the first core and the second core are not joined via the bonding resin, and a gap is formed between the first core and the second core. By employing such a scheme, for example, the inductive characteristics of the coil device can be adjusted accordingly to the width of the gap.

[0020] The first core and the second core may be combined to form an EE core, an EI core, a UU core, or a UI core. The E core or the U core has at least an outer leg portion, so that by forming at least one of the first core and the second core with the E core or the U core, the first core and the second core can be joined at the position of the outer leg portion via a bonding resin. Attached Figure Description

[0021] Figure 1A This is a perspective view of the coil device according to the first embodiment of the present invention.

[0022] Figure 1B It means from Figure 1A A three-dimensional view of the coil assembly in its state when the housing is removed.

[0023] Figure 2 yes Figure 1A An exploded perspective view of the coil device shown.

[0024] Figure 3 yes Figure 2 A three-dimensional view of the spool shown.

[0025] Figure 4 yes Figure 2 A perspective view of the spool, spool cover, and cap components shown.

[0026] Figure 5 It means in Figure 2 A three-dimensional view showing the state of the spool with the spool cover installed.

[0027] Figure 6 It means in Figure 5 A three-dimensional view showing the state of the spool cover with a second wire wound around it.

[0028] Figure 7A It is along Figure 1A The cross-sectional view of the coil assembly of line VIIA-VIIA is shown.

[0029] Figure 7B It is along Figure 1A The cross-sectional view of the coil assembly of line VIIB-VIIB is shown.

[0030] Figure 8 This is a perspective view of the coil device according to the second embodiment of the present invention.

[0031] Figure 9 It means Figure 7A Cross-sectional view of a deformed example of the shell shown.

[0032] Figure 10 It means Figure 7A A cross-sectional view of a deformed example of the core shown.

[0033] Figure 11 It means Figure 7A A cross-sectional view of another modified example of the shell shown.

[0034] Figure 12A This is a graph showing the simulation results of the stress distribution applied to the core assembly when the Young's modulus of the bonding resin is 90 MPa.

[0035] Figure 12B This is a graph showing the simulation results of the stress distribution applied to the core assembly when the Young's modulus of the bonding resin is 2 MPa.

[0036] Figure 13A This is a graph showing the simulation results of the displacement of the core assembly when the Young's modulus of the bonding resin is 90 MPa.

[0037] Figure 13B This is a graph showing the simulation results of the displacement of the core assembly when the Young's modulus of the bonding resin is 2 MPa.

[0038] Explanation of reference numerals in the attached figures

[0039] 10, 110 Coil assembly, 20 Bollard, 31 First coil section, 32 Second coil section, 40 Core assembly, 40a Upper core, 40b Lower core, 42a, 42b Divided cores, 44a, 44b Base, 440a, 440b Base surface, 441 Abutting part, 46a, 46b Middle leg, 48a, 48b Outer leg, 50 Partition cover, 60 Housing, 62 Base plate, 620 Upper surface, 622 Support part, 624 Gap, 64, 264 Side plates, 66 Protrusion, 68 Boss part, 69 Step part, 200 Bonding resin, 300 Encapsulating resin. Detailed Implementation

[0040] The present invention will now be described with reference to the embodiments shown in the accompanying drawings.

[0041] First Implementation Method

[0042] Figure 1A and Figure 1B The coil device 10 of the first embodiment of the present invention shown can be used, for example, as a transformer, and can be used in vehicle power circuits, etc. The coil device 10 has: a core assembly 40; and a housing 60 for housing at least a portion of the core assembly 40. Details regarding the core assembly 40 and the housing 60 will be described later.

[0043] like Figure 2 As shown, the coil assembly 10, in addition to the core assembly 40 and the housing 60, also includes a bobbin 20, a separator 50, a heat sink (top plate) 70, cover components 80a and 80b, and bobbin covers 90a and 90b. Figure 4 The structure of these components will now be described. In the accompanying drawings, the X-axis is aligned with the direction in which the first cores 40a, 40a are arranged. Furthermore, the Y-axis is aligned with the direction in which the first base 25a and the second base 25b of the bobbin 20 are arranged. Additionally, the Z-axis corresponds to the height (thickness) of the transformer 10 and is parallel to the spools of the coil sections 31, 32, which will be described later.

[0044] like Figure 3 As shown, the spool 20 has a spool base plate 21. The spool base plate 21 is a generally elliptical flat plate, forming the bottom of the spool 20. Legs 22, 22 are formed at each end of the spool base plate 21 in the Y-axis direction. The legs 22 protrude downwards from the spool base plate 21, serving to support the spool 20. A concave portion 22a is formed on the bottom surface of the leg 22, which can accommodate... Figure 2 Block 102 shown is as follows Figure 5 The block 102 is arranged inside the recessed portion 22a in the manner shown. The block 102 is composed of a block-shaped component with thermal conductivity, for example, made of metal.

[0045] A first hollow cylindrical portion 23 is integrally formed at approximately the center of the linear substrate 21, extending upwards. The first hollow cylindrical portion 23 has a cylindrical shape, and a first wire 37 can be wound around its outer surface. Figure 4 A separation plate fixing part 28 is formed on the inner surface of the first hollow cylindrical part 23. A pair of separation plate fixing parts 28 are formed on the inner surface of the first hollow cylindrical part 23; only one of them is shown in the accompanying drawings. Figure 2 As shown, a generally flat plate portion 106 can be fixed to the separating plate fixing portion 28 in a manner that is approximately perpendicular to the bobbin base plate 21. Furthermore, the separating plate portion 106 is made of a metal material such as aluminum.

[0046] The separation plate fixing part 28 extends in the Z-axis direction and is disposed between the middle legs 46a, 46a of the two first cores 40a, 40a that are opposite to each other in the X-axis direction, and between the middle legs 46b, 46b of the second cores 40b, 40b. The separation plate fixing part 28 is used to ensure that the middle legs 46a, 46a (middle legs 46b, 46b) that are opposite to each other in the X-axis direction are opposite to each other inside the first hollow cylinder part 23 with a predetermined gap and do not contact each other. The separation plate part 106, which is fixed to the separation plate fixing part 28, also has the same function.

[0047] A spool upper flange 24 is formed on the upper part of the first hollow cylindrical portion 23. The spool upper flange 24 is integrally formed on the upper end of the first hollow cylindrical portion 23 and protrudes radially in a direction parallel to the XY plane. A pedestal 25a is integrally formed on one end of the spool upper flange 24 in the Y-axis direction, and a pedestal 25b is integrally formed on the other end of the spool upper flange 24 in the Y-axis direction. The pedestals 25a and 25b have the same structure, therefore, the description of the structure of the pedestal 25b is omitted below.

[0048] The pedestal 25a has a bottom surface 250. The bottom surface 250 forms the bottom surface of the pedestal 25a and has an elongated shape in the X-axis direction. Around the bottom surface 250, an insulating wall 251 and outer walls 252a to 252c are formed to surround the bottom surface 250. The insulating wall 251 and outer walls 252a to 252c are formed to protrude upward.

[0049] An insulating wall 251 is formed in the bottom portion 250 at the boundary with the flange 24 on the spool. A [missing information - likely a device or component] is mounted on the spool 20. Figure 2 When the first cores 40a and 40a are shown, the insulating wall 251 can prevent the base bottoms 44a and 44b of the first cores 40a and 40a from contacting the second lead portion 38a of the second wire 38 inserted into the inner side of the base 25a.

[0050] The outer walls 252a to 252c are formed opposite to the insulating wall 251 in the Y-axis direction. The outer wall 252a is integrally formed with the insulating wall 251, and a portion of the outer wall 252a extends along one end of the bottom portion 250 in the X-axis direction. The other end of the bottom portion 250 in the X-axis direction is open to allow for the outlet... Figure 2 The second lead portions 38a and 38b of the second wire 38 are shown. Furthermore, in the base 25b, the end on the other side of the bottom surface 250 in the X-axis direction is open so that the first lead portions 37a and 37b of the first wire 37 can be led out.

[0051] Outer walls 252a and 252b are formed adjacent to each other in the X-axis direction, separated by an outer wall notch 253a, and outer walls 252b and 252c are formed adjacent to each other in the X-axis direction, separated by an outer wall notch 253b. On the bottom surface 250, a bottom surface notch 254a is formed continuously in the Y-axis direction from the outer wall notch 253a, and a bottom surface notch 254b is formed continuously in the Y-axis direction from the outer wall notch 253b.

[0052] A partition wall 255 is formed between the insulating wall 251 and the outer wall 252c. The partition wall 255 is arranged substantially parallel to the insulating wall 251 and the outer wall 252c and extends along the X-axis direction.

[0053] 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 used for insertion. Figure 2 The second lead portion 38b of the second wire 38 is shown. The first insertion passage 256a extends from the position where the bottom notch 254a is formed, across the bottom notch 254b along the outer walls 252b and 252c, and in the X-axis direction. Furthermore, in the base 25b, the first insertion passage 256a is used for insertion. Figure 2 The first lead portion 37a of the first wire 37 shown.

[0054] A second insertion passage 256b is formed on the other side of the partition wall 255 in the Y-axis direction. The second insertion passage 256b is used for insertion. Figure 2 The second lead portion 38a of the second wire 38 is shown. The second insertion passage 256b extends along the partition wall 255 in the X-axis direction from the position where the bottom notch 254b is formed. The extension directions of the second insertion passage 256b and the first insertion passage 256a are approximately parallel. Furthermore, the second insertion passage 256b is used for insertion on the base 25b. Figure 2 The first lead portion 37b of the first wire 37 shown.

[0055] A engaging protrusion 257a is formed on the outer surface of the insulating wall 251 on one side in the X-axis direction, and a engaging protrusion 257b is formed on the outer surface of the insulating wall 251 on the other side in the X-axis direction. The engaging protrusions 257a and 257b are used to engage with engaging recesses 82a and 82b formed on the cover member 80a (described later). Furthermore, in the base 25b, the engaging protrusions 257a and 257b are used to engage with engaging recesses 82a and 82b of the cover member 80b.

[0056] On the outer peripheral surface of the first hollow cylindrical portion 23, a plurality of positioning protrusions 26 are formed at predetermined intervals along the circumferential direction of the first hollow cylindrical portion 23. Each positioning protrusion 26 is formed at the lower end of the outer peripheral surface of the first hollow cylindrical portion 23 and protrudes radially outward from the outer peripheral surface. The positioning protrusions 26 are for mounting the spool covers 90a, 90b (which are mounted on their outer periphery) Figure 4 The positioning is set for the spool. When the spool covers 90a and 90b are installed on the spool 20, the inner circumferential surface of the second hollow cylindrical portion 91 of the spool covers 90a and 90b can be positioned at a position that is separated from the outer circumferential surface of the first hollow cylindrical portion 23 by the radial protrusion length of the positioning protrusion 26.

[0057] A first wire fixing portion 27 is formed on the outer peripheral surface of the first hollow cylindrical portion 23. The first wire fixing portion 27 is formed above the positioning protrusion 26 at a position approximately the width of one wire of the first wire 37, spaced apart from the positioning protrusion 26. The first wire fixing portion 27 protrudes radially outward from the outer peripheral surface of the first hollow cylindrical portion 23. The shape of the first wire fixing portion 27 is a thin plate shape, but its shape is not particularly limited and various shapes with protrusions can be adopted. The first lead portion 37b of the first wire 37 can be hooked and fixed in place by the first wire fixing portion 27. In addition, the first wire 37 can be inserted into the gap in the Z-axis direction between the first wire fixing portion 27 and the positioning protrusion 26, and the first wire 37 can be wound around the lower end of the first hollow cylindrical portion 23 circumferentially.

[0058] like Figure 5 As shown, a fitting groove 29 is formed on the bottom surface of the base 25a. The fitting groove 29 is formed approximately at the center of the base 25a in the X-axis direction and extends along the Y-axis direction. The fitting groove 29 is composed of a groove of a predetermined depth, which allows the cover partition 94a of the spool cover 90a to ( Figure 4 The upper end of the spool cover 90b is fitted into the fitting groove 29. In addition, in the base 25b, the upper end of the cover partition 94b of the spool cover 90b can be fitted into the fitting groove 29.

[0059] like Figure 4As shown, a first wire 37 can be wound around the outer peripheral surface of the first hollow cylindrical portion 23. More specifically, the first wire 37 is wound multiple turns above the first wire fixing portion 27 on the outer peripheral surface of the first hollow cylindrical portion 23, and one turn is wound below the first wire fixing portion 27 (the lower end of the first hollow cylindrical portion 23). Thus, a first coil portion 31, obtained by winding the first wire 37, is formed on the outer peripheral surface of the first hollow cylindrical portion 23. Furthermore, as a method for winding the first wire 37, aligned winding or α-winding, etc., can be used.

[0060] The first lead portion 37b of the first wire 37 rises from below the first wire fixing portion 27 toward the base 25b. More specifically, the first lead portion 37b is hooked onto the first wire fixing portion 27 and rises upward, being guided from the outside to the inside of the base 25b in the Y-axis direction via the outer wall notch 253b. The first lead portion 37b is guided further inside the base 25b in the Y-axis direction via the bottom notch 254b, and in a state of being bent approximately perpendicularly toward the positive X-axis direction, it is inserted into the second insertion passage 256b and led out to the outside in the X-axis direction.

[0061] On the other hand, the first lead wire portion 37a rises from the upper end of the outer peripheral surface of the first hollow cylinder portion 23 toward the pedestal 25b. More specifically, the first lead wire portion 37a is guided from the outer side to the inner side of the pedestal 25b in the Y-axis direction via the outer notch portion 253a. The first lead wire portion 37a is guided further inward in the Y-axis direction of the pedestal 25b via the bottom notch portion 254a, and in a state of being bent approximately perpendicular to the positive X-axis direction, it is inserted into the first insertion passage 256a and led out to the outer side in the X-axis direction.

[0062] The spool covers 90a and 90b are mounted on the spool 20 with the first wire 37 wound around the outer periphery of the first hollow cylindrical portion 23. Each of the spool covers 90a and 90b is a freely split body, and they are configured to be combined. Hereinafter, the repeated structures in the spool covers 90a and 90b will only be described for the spool cover 90a; the description of the spool cover 90b will be omitted.

[0063] The spool cover 90a has a second hollow cylindrical portion 91. The second hollow cylindrical portion 91 is composed of two separate parts, and when the second hollow cylindrical portion 91 of the spool cover 90a and the second hollow cylindrical portion 91 of the spool cover 90b are combined, a cylindrical body can be formed. A second wire 38 can be wound around the outer peripheral surface of the second hollow cylindrical portion 91.

[0064] A cover partition 94a is formed on the outer peripheral surface of the second hollow cylindrical portion 91. The cover partition 94a is formed at the upper end of the second hollow cylindrical portion 91 and protrudes radially outward from the outer peripheral surface of the second hollow cylindrical portion 91. The cover partition 94a has a predetermined length in the Z-axis direction, and its upper end can be... Figure 5 It is fitted into the fitting groove 29 of the base 25a in the manner shown.

[0065] A pair of cover flanges 92a, 92a are formed on the upper part of the second hollow cylindrical portion 91. One cover flange 92a is formed on one side of the cover partition 94a, and the other cover flange 92a is formed on the other side of the cover partition 94a. The cover flanges 92a, 92a are integrally formed on the upper end of the second hollow cylindrical portion 91 and protrude radially in a direction parallel to the XY plane.

[0066] A lead wire insertion passage 95 is formed between the cover partition 94a and the cover flange 92a formed on one side thereon, and a lead wire insertion passage 96 is formed between the cover partition 94a and the cover flange 92a formed on the other side thereon. The second lead portion 38a of the second wire 38 can be inserted into the lead wire insertion passage 95, and the second lead portion 38b of the second wire 38 can be inserted into the lead wire insertion passage 96.

[0067] A plurality of upper protrusions 97 are formed on the upper surface of the flange portion 92a. The upper protrusions 97 are used for, for example... Figure 5 When the spool covers 90a and 90b are fixed to the spool 20 as shown, a gap is formed between the flange portion 92a on the cover and the bottom surface of the base 25a of the spool 20 (or the bottom surface of the flange portion 24 on the spool).

[0068] like Figure 4 As shown, at each end of a pair of flange portions 92a, 92a, one of a pair of engaging portions 98, 98 is formed. Each engaging portion 98, 98 is formed by a protrusion or a recess, and can engage with the engaging portions 98, 98 formed at both ends of the flange portion 92b of the spindle cover 90b.

[0069] A lower flange portion 93 is formed at the lower part of the second hollow cylindrical portion 91. The lower flange portion 93 is integrally formed at the lower end of the second hollow cylindrical portion 91 and protrudes radially in a direction parallel to the XY plane.

[0070] like Figure 5 As shown, a second wire fixing portion 99 is formed on the outer peripheral surface of the second hollow cylindrical portion 91. The second wire fixing portion 99 is formed above the lower flange portion 93 at a position approximately the width of one wire of the second wire 38, spaced apart from the lower flange portion 93. The second wire fixing portion 99 protrudes outward from the outer peripheral surface of the second hollow cylindrical portion 91. The shape of the second wire fixing portion 99 is a thin plate shape, but its shape is not particularly limited, and various shapes with protrusions can be adopted.

[0071] The second wire fixing part 99 has a first wire fixing part 27 formed on the outer peripheral surface of the first hollow cylindrical part 23. Figure 4It has the same function. That is, it can hold and fix the second lead portion 38b of the second wire 38 in the second wire fixing portion 99. It can insert the second wire 38 into the gap between the second wire fixing portion 99 and the lower flange portion 93, and can wind the second wire 38 around the lower end of the second hollow cylinder portion 91 in its circumferential direction.

[0072] like Figure 4 As shown, the structures of the upper flange portion 92b and the cover partition portion 94b in the spool cover 90b are different from the structures of the upper flange portions 92a, 92a and the cover partition portion 94a in the spool cover 90a. More specifically, the upper flange portion 92b is continuously formed along the outer periphery of the upper part of the second hollow cylindrical portion 91.

[0073] The cover partition 94b is formed to protrude upward from the upper surface of the cover flange 92b. The cover partition 94b has a predetermined length in the Y-axis direction, and its upper end can be fitted into the fitting groove 29 of the base 25b.

[0074] like Figure 6 As shown, a second wire 38 can be wound around the outer peripheral surface of the second hollow cylindrical portion 91 of the wire shaft covers 90a and 90b. More specifically, the second wire 38 is wound multiple turns above the second wire fixing portion 99 on the outer peripheral surface of the second hollow cylindrical portion 91, and one turn is wound below the second wire fixing portion 99 (the lower end of the second hollow cylindrical portion 91). Thus, a second coil portion 32 obtained by winding the second wire 38 is formed on the outer peripheral surface of the second hollow cylindrical portion 91.

[0075] The second lead portion 38b of the second wire 38 rises from below the second wire fixing portion 99 toward the base 25a. More specifically, the second lead portion 38b is hooked onto the second wire fixing portion 99 and rises upward, guided from the outside to the inside of the base 25a in the Y-axis direction via the outer wall notch 253a. The second lead portion 38b is guided further inside the base 25a in the Y-axis direction via the bottom notch 254a, and in a state of being bent approximately perpendicular to the positive X-axis direction, it is inserted into the first insertion passage 256a and led out to the outside in the X-axis direction.

[0076] On the other hand, the second lead portion 38a rises from the upper end of the outer peripheral surface of the second hollow cylinder portion 91 toward the pedestal 25a. More specifically, the second lead portion 38a is guided from the outer side to the inner side of the pedestal 25a in the Y-axis direction via the outer notch 253b. The second lead portion 38a is guided further inward in the Y-axis direction of the pedestal 25a via the bottom notch 254b, and in a state of being bent approximately perpendicular to the positive X-axis direction, it is inserted into the second insertion passage 256b and led out to the outer side in the X-axis direction.

[0077] Through such Figure 4As shown, the first wire 37 is wound around the outer peripheral surface of the first hollow cylindrical portion 23, and as... Figure 6 As shown, the second wire 38 is wound around the outer peripheral surface of the second hollow cylindrical portion 91, which can form a shape as shown. Figure 7A As shown, the coil section has a double-layer structure with a first coil section 31 arranged on the inner side and a second coil section 32 arranged on the outer side. Either the first coil section 31 or the second coil section 32 constitutes a primary coil, and the other constitutes a secondary coil.

[0078] like Figure 4 As shown, cover component 80a can be mounted on base 25a, and cover component 80b can be mounted on base 25b. Cover component 80a and cover component 80b have the same structure, therefore, the description of the structure of cover component 80b is omitted below.

[0079] The cover member 80a has a top plate portion 81. A pair of inner side walls 82, 82 and a pair of outer side walls 83, 83 are formed on the sides of the top plate portion 81. The outer side walls 83, 83 are 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.

[0080] The outer side walls 83, 83 of the cover member 80a are arranged to overlap with the outer walls 252a to 252c of the pedestal 25a, and the outer side walls 83, 83 of the cover member 80b are arranged to overlap with the outer walls 252a to 252c of the pedestal 25b.

[0081] A pair of inner sidewalls 82, 82 are each spaced apart by a predetermined interval in the X-axis direction. An engaging recess 82a is formed on one inner sidewall 82, and an engaging recess 82b is formed on the other inner sidewall 82. By making... Figure 3 The engaging protrusion 257a shown engages with the engaging recess 82a, and makes... Figure 3 The engaging protrusion 257b shown engages with the engaging recess 82b, enabling the cover component 80a to be mounted on the base 25a.

[0082] like Figure 2 As shown, partition covers 50 and 50 can be arranged on the outside of the online shaft covers 90a and 90b. One partition cover 50 is formed on one side of the online shaft covers 90a and 90b in the X-axis direction, and the other partition cover 50 is formed on the other side of the online shaft covers 90a and 90b in the X-axis direction.

[0083] The separator cover 50 includes: a cover body 52; and a pair of locking tabs 54, 54 formed at both ends of the cover body 52 in the Z-axis direction. The cover body 52 is bent in such a way that it can cover the area around the second coil portion 32 formed on the outer peripheral surface of the second hollow cylindrical portion 91, 91 of the spool covers 90a, 90b. The locking tabs 54 are bent inward from the cover body 52 in a direction substantially perpendicular to the cover body 52. ​​The pair of locking tabs 54, 54 can be mounted in such a way that they clamp the upper flange portions 92a, 92b formed at the upper end of the second hollow cylindrical portion 91, 91 of the spool covers 90a, 90b and the lower flange portions 93, 93 formed at the lower end of the second hollow cylindrical portion 91, 91 of the spool covers 90a, 90b.

[0084] like Figure 7B As shown, it can be configured on the outside of the online shaft covers 90a and 90b. Figure 2 The insulating covers 103, 103 are shown. The insulating cover 103 has a cover body 104 and a fold-back portion 105. The cover body 104 is disposed along the inner surface of the side plate 64 of the housing 60 (described later), and the fold-back portion 105 is configured to engage with the upper end of the side plate 64. The insulating cover 103 is used to prevent the second coil portion 32 formed on the outer peripheral surface of the second hollow cylindrical portion 91 of the wire shaft covers 90a, 90b from contacting the side plate 64.

[0085] like Figure 2 As shown, terminals 100 and 100 are respectively installed at the ends of the first lead portions 37a and 37b of the first wire 37. Furthermore, the first lead portions 37a and 37b are enclosed by an insulating wire cover 101. Similarly, terminals 100 and 100 are respectively installed at the ends of the second lead portions 38a and 38b of the second wire 38. Furthermore, the second lead portions 38a and 38b are enclosed by an insulating wire cover 101.

[0086] like Figure 7A As shown, at least a portion of the core assembly 40 is housed within the housing 60. In the illustrated example, the upper cores 40a, 40a, and a portion thereof, and the lower cores 40b, 40b, are housed inside the housing 60. The base surfaces 440b, 440b of the bases 44b, 44b are mounted on the bottom plate (bottom) 62 of the housing 60, forming the mounting sides of the lower cores 40b, 40b. The housing 60 is constructed of plate-shaped components and is made of a highly thermally conductive metal material, such as aluminum, and functions as a heat dissipation housing.

[0087] like Figure 2 and Figure 7AAs shown, the housing 60 has a base plate 62 and side plates 64. The side plates 64 extend upwards and are formed on the periphery of the base plate 62. More specifically, the side plates 64 are formed on each side of the base plate 62, which is generally quadrilateral in shape when viewed from above, and have two opposing surfaces parallel to the YZ plane and two opposing surfaces generally parallel to the XZ plane. A bulge 66 is formed on each of the two surfaces of the side plates 64 that are generally parallel to the XZ plane. The bulge 66 is composed of a portion bulging outwards in the Y-axis direction, and a recess is formed inside the housing 60 at the location where the bulge 66 is formed. A [device / structure] can be disposed within this recess. Figure 6 A portion of the second coil section 32 shown. The housing 60 (e.g., base plate 62) is directly or indirectly fixed to a cooling mechanism (not shown).

[0088] Two bosses 68, 68 are formed at the corners of the base plate 62. An opening (e.g., a bolt hole) is formed in the boss 68, and the housing 60 can be fixed to a cooling mechanism, etc., by fixing fasteners or the like in the opening.

[0089] The interior of the housing 60 is filled with potting resin 300. The potting resin 300 is a heat-dissipating resin with high thermal conductivity, and is filled between the side of the core assembly 40 and the side plate 64 of the housing 60, the periphery of the first coil portion 31, or the periphery of the second coil portion 32, etc.

[0090] The Young's modulus of the potting resin 300 is preferably 10 MPa or less, and more preferably 0.1 to 10 MPa. Materials constituting the potting resin 300 may include silicone resin, polyurethane resin, epoxy resin, etc., which are flexible after injection.

[0091] The core assembly 40 has upper cores 40a and 40b and lower cores 40b. The core assembly 40 constitutes a so-called longitudinal core, and the upper cores 40a and 40b and the lower cores 40b and 40b are configured to be assembled in the Z-axis direction. The material of each core 40a and 40b can be a soft magnetic material such as metal or ferrite, but there is no particular limitation.

[0092] The upper cores 40a and 40a are each composed of two segmented cores 42a and 42a, each having the same shape, and are divided by a surface parallel to the YZ plane. When combined along the X-axis, the upper cores 40a and 40a have an E-shaped cross-section (a cross-section parallel to the XZ plane), forming a so-called E-type core. Furthermore, the upper cores 40a and 40a are not limited to E-type cores; they can also be composed of, for example, U-shaped cores (preferably cores with outer legs).

[0093] The lower cores 40b and 40b are each composed of two segmented cores 42b and 42b, each having the same shape, and are divided by a surface parallel to the YZ plane. When combined along the X-axis, the lower cores 40b and 40b have an E-shaped cross-section (a cross-section parallel to the XZ plane), forming a so-called E-type core. Furthermore, the lower cores 40b and 40b are not limited to E-type cores; they can also be composed of, for example, U-shaped cores (preferably cores with outer legs).

[0094] Each of the upper cores 40a and 40a has: a base 44a extending in the X-axis direction; a middle leg 46a protruding in the Z-axis direction from one end of the base 44a in the X-axis direction; and an outer leg 48a protruding in the Z-axis direction from the other end of the base 44a in the X-axis direction. The upper cores 40a and 40a can be combined along the X-axis direction at the position of the middle legs 46a and 46a. That is, in this embodiment, the upper cores 40a and 40a are divided at the position of the middle legs 46a and 46a, but are not divided at the position of the outer legs 48a and 48a.

[0095] With the upper cores 40a and 40a assembled along the X-axis, the middle legs 46a and 46a are positioned between the outer legs 48a and 48a of the upper cores 40a and 40a. The pair of middle legs 46a and 46a can be inserted from above in the Z-axis direction into the through hole of the first hollow cylindrical portion 23 of the spool 20. Hereinafter, the surfaces of the bases 44a and 44a will be referred to as base surfaces 440a and 440a.

[0096] Each of the lower cores 40b and 40b has: a base 44b extending in the X-axis direction; a middle leg 46b protruding in the Z-axis direction from one end of the base 44b in the X-axis direction; and an outer leg 48b protruding in the Z-axis direction from the other end of the base 44b in the X-axis direction. The lower cores 40b and 40b can be combined along the X-axis direction at the position of the middle legs 46b and 46b. That is, in this embodiment, the lower cores 40b and 40b are separated at the position of the middle legs 46b and 46b, but are not separated at the position of the outer legs 48b and 48b.

[0097] With the lower cores 40b and 40b assembled along the X-axis, the middle legs 46b and 46b are positioned between the outer legs 48b and 48b of the lower cores 40b and 40b. A pair of middle legs 46b and 46b can be inserted from below along the Z-axis into the through hole of the first hollow cylindrical portion 23 of the spool 20. Hereinafter, the surfaces of the bases 44b and 44b will be referred to as base surfaces 440b and 440b.

[0098] The outer legs 48a, 48a of the upper cores 40a, 40a and the outer legs 48b, 48b of the lower cores 40b, 40b, are joined together in the Z-axis direction on the outer side of the spool 20. The middle legs 46a, 46a of the upper cores 40a, 40a and the middle legs 46b, 46b of the lower cores 40b, 40b, are joined together in the Z-axis direction on the inner side of the spool 20. The base surfaces 440b, 440b of the lower cores 40b, 40b, on the opposite side of the joint (butting surface) between the upper cores 40a, 40a and the lower cores 40b, 40b, are in contact with the base plate 62 along a plane perpendicular to the Z-axis direction (XY plane).

[0099] like Figure 7A As shown in the enlarged view, the outer legs 48a, 48a of the upper cores 40a, 40a and the outer legs 48b, 48b of the lower cores 40b, 40b are bonded to each other in the Z-axis direction via a bonding resin (e.g., adhesive) 200. Furthermore, the middle legs 46a, 46a of the upper cores 40a, 40a and the middle legs 46b, 46b of the lower cores 40b, 40b are also bonded to each other in the Z-axis direction via a bonding resin 200. Therefore, a thin layer (buffer layer) of bonding resin 200 is formed at the joint between the upper cores 40a, 40a and the lower cores 40b, 40b. The upper cores 40a, 40a and the lower cores 40b, 40b are mechanically weakly bonded, as described later, and are not completely integrated via the bonding resin 200.

[0100] With the upper cores 40a and 40b joined together, the core assembly 40 has a dimension of 25mm or more in the X-axis direction, a dimension of 25mm or more in the Y-axis direction, and a dimension of 20mm or more in the Z-axis direction. This invention achieves good results in such a relatively large core assembly 40.

[0101] The bonding resin 200 is composed of a soft resin, and its Young's modulus is preferably 90 MPa or less, more preferably 2 to 20 MPa, at a temperature between 20 and 150°C. Furthermore, the glass transition temperature Tg of the bonding resin 200 is 0°C or less.

[0102] By ensuring that the Young's modulus or glass transition temperature Tg of the bonding resin 200 is within the aforementioned range, the mechanical bond between the upper cores 40a, 40a and the lower cores 40b, 40b can be maintained at a relatively weak level, thus preventing breakage of the lower cores 40b, 40b as described later. As a material constituting the bonding resin 200, silicone resin, polyurethane resin, epoxy resin, etc., can be used; such resins maintain a soft state after injection. Furthermore, the bonding resin 200 can also be a resin obtained by mixing multiple resins.

[0103] The Young's modulus of the bonding resin 200 used to join the front ends of the outer legs 48a, 48a and the outer legs 48b, 48b in the Z-axis direction to each other may be different from the Young's modulus of the bonding resin 200 used to join the front ends of the middle legs 46a, 46a and the middle legs 46b, 46b in the Z-axis direction to each other; either one may have a Young's modulus greater than the other.

[0104] The thickness of the resin layer (adhesive layer) formed by the bonding resin 200 is preferably 8 to 100 μm, more preferably 8 to 20 μm. By keeping the thickness of the bonding resin 200 within the above range, the mechanical bonding between the upper cores 40a, 40a and the lower cores 40b, 40b can be maintained at a relatively weak level, and as will be described later, damage to the lower cores 40b, 40b can be prevented.

[0105] In the illustrated example, the upper cores 40a, 40a and the lower cores 40b, 40b are joined by the joining resin 200 at the positions of the outer legs 48a, 48a and the middle legs 46a, 46a, but it is also possible that they are joined by the joining resin 200 only at the positions of the outer legs 48a, 48a.

[0106] The Young's modulus of bonding resin 200 is different from that of potting resin 300; the Young's modulus of bonding resin 200 is greater than that of potting resin 300.

[0107] The upper surface of the potting resin 300 filling the interior of the housing 60 is located above the junction of the upper cores 40a, 40a and the lower cores 40b, 40b. Since the junction of the upper cores 40a, 40a and the lower cores 40b, 40b is filled with bonding resin 200, the potting resin 300 does not enter the junction but is only connected to the bonding resin 200 filling the junction. Furthermore, from the viewpoint of improving the heat dissipation of the coil device 10, it is preferable that the thermal conductivity of the potting resin 300 is greater than that of the bonding resin 200.

[0108] The outer legs 48a, 48a or the middle legs 46a, 46a are surrounded by potting resin 300. Therefore, at the joint between the upper cores 40a, 40a and the lower cores 40b, 40b, the resin layer formed by the bonding resin 200 is surrounded by potting resin 300.

[0109] like Figure 2 As shown, a pair of heat sinks 70, 70 can be mounted on the core assembly 40. The heat sink 70 has an upper surface cover 72 and a side cover 74. (As shown...) Figure 1BAs shown, the upper surface cover 72 is fixed to the base surface 440a of the base 44a, and the side cover 74 is fixed to the outer surfaces of the outer legs 48a and 48b respectively in a manner that spans the outer legs 48a and 48b.

[0110] In the manufacture of the coil device 10, firstly, preparation Figure 2 The components are shown. Next, as... Figure 4 As shown, a first wire 37 is wound around the outer periphery of the first hollow cylindrical portion 23 of the spool 20 to form a first coil portion 31. Furthermore, from the lower end of the first hollow cylindrical portion 23, the first lead portion 37b of the first wire 37 is hooked onto the first wire fixing portion 27 and led out towards the pedestal 25b. At this time, the first lead portion 37b, which is erected on the pedestal 25b, is led out along the Y-axis direction from the outside of the pedestal 25b through the outer wall notch 253b and the bottom notch 254b to the position of the second insertion passage 256b, and then led outward in the X-axis direction through the second insertion passage 256b.

[0111] Additionally, from the upper end of the first hollow cylindrical portion 23, the first lead portion 37a of the first wire 37 is led out to the base 25b. At this time, the first lead portion 37a is led out along the Y-axis direction from the outside of the base 25b through the outer wall notch 253a and the bottom notch 254a to the position of the first insertion passage 256a, and then led outward along the X-axis direction through the first insertion passage 256a.

[0112] Next, as Figure 5 As shown, spool covers 90a and 90b are mounted on the spool 20 in a manner that covers the area around the first coil portion 31, as... Figure 6 As shown, a second wire 38 is wound around the outer peripheral surface of the second hollow cylindrical portion 91 to form a second coil portion 32. Next, from the lower end of the second hollow cylindrical portion 91, the second lead portion 38b of the second wire 38 is hooked onto the second wire fixing portion 99 and led out to the base 25a. At this time, the second lead portion 38b is led out along the Y-axis direction from the outside of the base 25a through the outer wall notch 253a and the bottom notch 254a to the position of the first insertion passage 256a, and then led outward in the X-axis direction through the first insertion passage 256a.

[0113] Furthermore, from the upper end of the second hollow cylindrical portion 91, the second lead portion 38a of the second wire 38 is led out to the base 25a. At this time, the second lead portion 38a is led out along the Y-axis direction from the outside of the base 25a through the outer wall notch 253b and the bottom notch 254b to the position of the second insertion passage 256b, and then led outward in the X-axis direction through the second insertion passage 256b.

[0114] Next, in a manner that covers the area around the second coil portion 32, Figure 2The partitions 50 and 50 shown are as follows Figure 7A The shaft covers 90a and 90b are installed as shown, and the separation plate part 106 is installed on the separation plate fixing part 28.

[0115] Next, the middle legs 46a and 46a are inserted from above into the through hole of the first hollow cylinder 23 and the upper cores 40a and 40a are mounted on the spool 20. The middle legs 46b and 46b are inserted from below into the through hole of the first hollow cylinder 23 and the lower cores 40b and 40b are mounted on the spool 20, thus forming the core assembly 40.

[0116] At this time, bonding resin 200 is applied to the front ends of the middle legs 46a, 46a and / or the middle legs 46b, 46b, and bonding resin 200 is also applied to the front ends of the outer legs 48a, 48a and / or the outer legs 48b, 48b. Therefore, when the upper cores 40a, 40a and the lower cores 40b, 40b are assembled, the front ends of the middle legs 46a, 46a and the middle legs 46b, 46b can be joined to each other via bonding resin 200, and the front ends of the outer legs 48a, 48a and the outer legs 48b, 48b can be joined to each other via bonding resin 200. Furthermore, the timing of performing the process of joining the upper cores 40a, 40a and the lower cores 40b, 40b using bonding resin 200 can be appropriately changed.

[0117] Installed on the bases 25a and 25b before and after it. Figure 4 The cover components 80a and 80b are shown, and on the core assembly 40 are, as shown in the figure Figure 1B Install as shown Figure 2 The heat sinks 70 and 70 are shown. Additionally, Figure 2 The blocks 102 shown are fixed to the legs 22, 22 and the concave portions 22a, 22a of the shaft 20. Figure 5 (the interior of)

[0118] Next, the spool 20, on which the core assembly 40 is mounted, is housed inside the housing 60, and the insulating covers 103, 103 are positioned as follows: Figure 7B The core assembly 40 is engaged with the upper end of the side plate 64 of the housing 60 as shown. Next, potting resin 300 is injected into the interior of the housing 60, filling the gap between the side portion of the core assembly 40 and the side plate 64, and around the coil portions 31 and 32 with a predetermined amount of potting resin 300. Through the above process, a core assembly 40 is obtained. Figure 1A The coil device 10 is shown. In addition, terminals 100 and wire covers 101 can be installed on the first lead portions 37a, 37b and the second lead portions 38a, 38b as needed.

[0119] like Figure 7AAs shown, the coil device 10 of this embodiment includes: upper cores 40a, 40a and lower cores 40b, 40b bonded to each other via bonding resin 200; and a bottom 62 of a housing 60 in contact with the base surfaces 440b, 440b of the lower cores 40b, 40b. Therefore, when the bottom 62 is directly or indirectly fixed to, for example, a cooling mechanism (e.g., a water-cooling unit), the lower cores 40b, 40b in contact with the bottom 62 are cooled more efficiently than the upper cores 40a, 40a, resulting in a temperature difference between the upper cores 40a, 40a and the lower cores 40b, 40b. As a result, the temperature of the upper cores 40a, 40a becomes higher than the temperature of the lower cores 40b, 40b, and the displacement of the upper cores 40a, 40a becomes greater than the displacement of the lower cores 40b, 40b.

[0120] Even under these conditions, in the coil device 10 of this embodiment, the Young's modulus of the bonding resin 200 used to bond the upper cores 40a, 40a and the lower cores 40b, 40b is 90 MPa or less, and the bonding resin 200 is flexible. Therefore, the upper cores 40a, 40a and the lower cores 40b, 40b are mechanically bonded relatively weakly, and the displacement of the upper cores 40a, 40a does not easily affect the lower cores 40b, 40b. Therefore, it is possible to prevent the lower cores 40b, 40b from displacing in a manner that follows the displacement of the upper cores 40a, 40a, and it is possible to prevent the lower cores 40b, 40b from being subjected to excessive stress, effectively preventing cracks from forming in a portion of the lower cores 40b, 40b. Therefore, by employing the coil device 10 of this embodiment, a coil device that can effectively prevent core breakage can be realized.

[0121] Furthermore, simulation results conducted by the inventors of this invention confirmed that, as Figure 7A As shown, when the front ends of the upper cores 40a, 40a and the lower cores 40b, 40b are bonded together using a bonding resin 200 (specifically, a silicone resin) with a Young's modulus of 2 MPa, the stress applied to the lower cores 40b, 40b is reduced to less than half. This effectively prevents cracking near the roots of the outer legs 48b, 48b of the bases 44b, 44b. Furthermore, it was also confirmed that for the upper cores 40a, 40a, the reduced stress applied near the roots of the outer legs 48a, 48a of the bases 44a, 44a resulted in smaller displacement of the upper cores 40a, 40a themselves.

[0122] Figure 12A This is a graph showing the simulation results of the stress distribution applied to the core assembly 40 when the Young's modulus of the bonding resin 200 is 90 MPa. Additionally, Figure 12BThis is a graph showing the simulation results of the stress distribution applied to the core assembly 40 when the Young's modulus of the bonding resin 200 is 2 MPa. Figure 12A , 12B In the diagram, diagonal lines indicate the degree (relative magnitude) of stress applied to the upper cores 40a, 40a and the lower cores 40b, 40b. Specifically, the lower the density of the diagonal lines, the greater the stress applied, and the greater the density of the diagonal lines, the smaller the stress applied.

[0123] Will Figure 12A and Figure 12B A comparison shows that when the Young's modulus of the bonding resin 200 is reduced from 90 MPa to 2 MPa, the stress applied to the lower cores 40b, 40b (especially near the roots of the outer legs 48b, 48b of the base 44b, 44b) can be effectively reduced. Furthermore, when the Young's modulus of the bonding resin 200 is reduced from 90 MPa to 2 MPa, the stress applied to the upper cores 40a, 40a can also be effectively reduced. Additionally, as... Figure 12A As shown, when the Young's modulus of the bonding resin 200 is 90 MPa, the stress applied to the lower cores 40b, 40b (especially near the root of the outer legs 48b, 48b of the base 44b, 44b) is reduced.

[0124] Figure 13A This is a graph showing the simulation results of the displacement distribution of the core assembly 40 when the Young's modulus of the bonding resin 200 is 90 MPa. Additionally, Figure 13B This is a graph showing the simulation results of the displacement distribution of the core assembly 40 when the Young's modulus of the bonding resin 200 is 2 MPa. Figure 13A , 13B In the diagram, diagonal lines represent the degree (relative magnitude) of displacement of the upper cores 40a and 40b and the lower cores 40b. Specifically, the lower the density of the diagonal lines, the greater the displacement, and the higher the density of the diagonal lines, the smaller the displacement.

[0125] Will Figure 13A and Figure 13B A comparison shows that when the Young's modulus of the bonding resin 200 is 90 MPa and when the Young's modulus of the bonding resin 200 is 2 MPa, the displacement of the upper cores 40a, 40a and the lower cores 40b, 40b is almost unchanged. That is, when the Young's modulus of the bonding resin 200 is 90 MPa, it is possible to achieve the same level of suppression of the displacement of the upper cores 40a, 40a and the lower cores 40b, 40b as when the Young's modulus of the bonding resin 200 is 2 MPa.

[0126] In addition, the upper cores 40a and 40a and the lower cores 40b and 40b are thermally connected by bonding resin 200. The heat of the upper cores 40a and 40a can be well transferred to the base plate 62 through the lower cores 40b and 40b. Therefore, the heat dissipation of the upper cores 40a and 40a and the lower cores 40b and 40b can be maintained in a good state.

[0127] Furthermore, the glass transition temperature of the bonding resin 200 is below 0°C. Therefore, the bonding resin 200 remains in a soft rubber state even at lower temperatures (e.g., 0°C to room temperature). Thus, by using such a bonding resin 200 to bond the upper cores 40a, 40a and the lower cores 40b, 40b, the upper cores 40a, 40a and the lower cores 40b, 40b are mechanically bonded weakly. Even if a temperature difference arises between the upper cores 40a, 40a and the lower cores 40b, 40b, breakage of these cores can be effectively prevented.

[0128] In addition, the bottom 62 forms part of the housing 60 for housing the upper cores 40a, 40a and the lower cores 40b, 40b. Therefore, the heat from the upper cores 40a, 40a and the lower cores 40b, 40b can be dissipated through the various parts of the housing 60, which can further improve the heat dissipation performance of the coil device 10.

[0129] In addition, the interior of the housing 60 is filled with potting resin 300, so that the heat of the upper cores 40a, 40a and the lower cores 40b, 40b, etc. can be transferred to the housing 60 through the potting resin 300, and the heat can be effectively dissipated.

[0130] Furthermore, the upper surface of the potting resin 300 is located above the housing 60 at the junction of the upper cores 40a, 40a and the lower cores 40b, 40b. Therefore, inside the housing 60, not only are the lower cores 40b, 40b covered by the potting resin 300, but at least a portion of the upper cores 40a, 40a are also covered by the potting resin 300. Thus, the heat from the upper cores 40a, 40a and the lower cores 40b, 40b can be effectively dissipated through the potting resin 300.

[0131] In addition, the Young's modulus of the potting resin 300 is less than 10 MPa, and the Young's modulus of the bonding resin 200 is greater than that of the potting resin 300. Therefore, as described above, core breakage can be effectively prevented, and the upper cores 40a, 40a and the lower cores 40b, 40b can be bonded with good bonding strength via the bonding resin 200.

[0132] Second Implementation Method

[0133] Figure 8The coil device 110 of the second embodiment of the present invention shown differs only in the following aspects; the other structures are the same as those of the first embodiment described above, and the same effects can be obtained. In the drawings, the same reference numerals are used for components that are the same as those in the first embodiment, and repeated descriptions are omitted.

[0134] like Figure 8 As shown, in the coil device 110 of this embodiment, a gap G is formed between the middle legs 46a, 46a and the middle legs 46b, 46b, and the gap G is filled with potting resin 300. The width of the gap G in the Z-axis direction is preferably 10 to 100 μm. In this embodiment, the middle legs 46a, 46a and the middle legs 46b, 46b are not joined by bonding resin 200, and at the positions of the middle legs 46a, 46a and the middle legs 46b, 46b, the front ends of the upper cores 40a, 40a and the lower cores 40b, 40b are not filled with bonding resin 200.

[0135] The middle legs 46a, 46a and the middle legs 46b, 46b are joined by potting resin 300. In addition, the interior of the gap G may not be filled with potting resin 300 and may be a cavity.

[0136] In this embodiment, the same effects as in the first embodiment can be achieved. In addition, in this embodiment, the inductance characteristics of the coil device 110 can be adjusted in accordance with the Z-axis width of the gap G.

[0137] Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention.

[0138] (1) can be as follows Figure 9 As shown, a plurality of (eight) support portions 622 are integrally formed on the base plate 62, and the lower cores 40b, 40b are mounted on these support portions 622. Each support portion 622 consists of a protrusion (projection) extending from the upper surface 620 of the base plate 62. The plurality of support portions 622 are each discretely (partially) formed on the upper surface 620 of the base plate 62, making surface contact or point contact with the base surfaces 440b, 440b of the lower cores 40b, 40b. The support portions 622 support the base surfaces 440b, 440b at a distance spaced from the upper surface 620 above the upper surface 620 of the base plate 62. The upward protrusion length of the support portion 622 is preferably 0.05 to 1.5 mm, more preferably 0.1 to 1.0 mm. In the illustrated example, the protrusion length of the support portion 622 is less than the thickness of the base plate 62.

[0139] A gap 624 is formed between the upper surface 620 of the base plate 62 and the base surfaces 440b, 440b, and the gap is filled with potting resin 300. The base surfaces 440b, 440b are in partial contact with the base plate 62 and are partially connected to the base plate 62 via the potting resin 300.

[0140] The base surfaces 440b, 440b are raised above the upper surface 620 of the base plate 62 in positions other than where the support portion 622 is provided, and the entire base surfaces 440b, 440b are not in contact with the upper surface 620 of the base plate 62. Therefore, the contact area between the base surfaces 440b, 440b and the base plate 62 can be reduced, and the stress on the lower core 40b, 40b caused by the difference in their coefficients of thermal expansion can be reduced, preventing cracks from forming in the lower core 40b, 40b (especially near the root of the outer legs 48b, 48b of the base 44b, 44b).

[0141] Furthermore, at the location where the support portion 622 is provided, heat generated by the core assembly 40, etc., can be transferred to the base plate 62 via the support portion 622, and the heat can be dissipated via the base plate 62. Additionally, at locations other than the location where the support portion 622 is provided, heat generated by the core assembly 40, etc., can be dissipated via the potting resin 300 filled in the gap 624 and the base plate 62.

[0142] (2) can be as follows Figure 10 As shown, a plurality of (eight) abutment portions 441 are integrally formed on the base surfaces 440b, 440b of the lower cores 40b, 40b. Each abutment portion 441 is formed by a protrusion (raised portion) protruding from the base surfaces 440b, 440b of the base bottoms 44b, 44b. The shape and size of the abutment portions 441 are the same as those of the support portion 622 in the modified example (1) described above. The abutment portions 441 are discretely (partially) formed on the base surfaces 440b, 440b, and abut against the upper surface 620 of the bottom plate 62 of the housing 60 at a position spaced apart from the base surfaces 440b, 440b below the base surfaces 440b, 440b.

[0143] When the lower cores 40b, 40b are placed on the upper surface 620 of the base plate 62, the bases 44b, 44b partially abut (join) with the base plate 62. The gap 624 between the upper surface 620 of the base plate 62 and the base surfaces 440b, 440b is filled with potting resin 300, the lower cores 40b, 40b are in partial contact with the base plate 62, and the base surfaces 440b, 440b are partially connected to the base plate 62 via the potting resin 300.

[0144] exist Figure 10In the example shown, the contact area between the lower cores 40b, 40b and the bottom 62 can be reduced, thereby reducing the stress on the lower cores 40b, 40b caused by the difference in their coefficients of thermal expansion, and preventing cracks from forming in the lower cores 40b, 40b (especially near the root of the outer legs 48b, 48b of the base 44b, 44b). Furthermore, at locations other than where the abutment portion 441 is formed, heat generated by the core assembly 40, etc., can be effectively dissipated through the potting resin 300 and the base plate 62. At locations where the abutment portion 441 is formed, the aforementioned heat can be transferred to the base plate 62 via the abutment portion 441 and dissipated. Additionally, as shown in the figure, multiple (eight) abutment portions 441 can also be integrally formed on the base surfaces 440a, 440a of the upper cores 40a, 40a.

[0145] (3) can be as follows Figure 11 As shown, a stepped portion 69 is formed on the base plate 62 of the housing 60, and the lower cores 40b, 40b are placed on the upper surface of the stepped portion 69. The stepped portion 69 is formed separately from the base plate 62, constituting part of the side plate 64. In this case, a gap 624 is also formed between the base surfaces 440b, 440b and the base plate 62, so the contact area between the lower cores 40b, 40b and the bottom 62 is reduced, and the same effect as the above-described modifications (1) and (2) can be obtained.

[0146] (4) In the above embodiments, such as Figure 7A As shown, the upper cores 40a, 40a and the lower cores 40b, 40b are housed inside the housing 60, but the housing 60 is not necessary. For example, the upper cores 40a, 40a and the lower cores 40b, 40b may simply be mounted on a plate (heat sink) of metal or the like, in a flat plate shape. Furthermore, in this case, it is preferable that the plate is directly or indirectly fixed to the cooling mechanism.

[0147] (5) In the above embodiments, the base plate 62 and the side plate 64 are both made of metal, but the side plate 64 may also be made of, for example, a resin molded body.

[0148] (6) In the above embodiments, such as Figure 2 As shown, the core assembly 40 is composed of E-type cores combined with each other, but it can also be composed of U-type cores combined with each other, E-type cores and I-type cores, E-type cores and I-type cores, or cores of other shapes. The E-type core or U-type core, etc., has at least an outer leg portion. Therefore, by forming at least one of the upper cores 40a, 40a and the lower cores 40b, 40b from E-type cores or U-type cores, the upper cores 40a, 40a and the lower cores 40b, 40b can be joined at the outer leg portion via a bonding resin.

[0149] (7) In the above embodiments, such as Figure 2 As shown, the upper cores 40a and 40b are composed of segmented cores that are each divided in the X-axis direction, but they can also be formed integrally. The lower cores 40b and 40b are the same.

[0150] (8) In the above embodiments, examples of applying the present invention to transformers have been described, but the present invention can also be applied to other coil devices.

[0151] (9) In the second embodiment described above, the gap G may be filled with bonding resin 200 instead of potting resin 300.

Claims

1. A coil device, characterized in that, have: A first core and a second core, arranged along a first axial direction and joined together by a bonding resin; and A cooling plate-shaped component contacts the second core on the opposite side of the joint between the first core and the second core along a surface perpendicular to the first axial direction. A portion of the first core and the second core are housed within the housing. The interior of the housing is filled with potting resin. The upper surface of the potting resin filling the interior of the housing is located above the housing, above the junction of the first core and the second core. The Young's modulus of the bonding resin is below 90 MPa. The Young's modulus of the potting resin is less than 10 MPa, and the Young's modulus of the bonding resin is greater than that of the potting resin. The glass transition temperature of the bonding resin is below 0°C. The cooling plate-like component forms part of a housing for receiving the first core and the second core. The bonding resin is a resin that can maintain a soft state even after injection. The potting resin is connected to the bonding resin of the joint. The thermal conductivity of the potting resin is greater than that of the bonding resin.

2. The coil device according to claim 1, characterized in that: At least one of the first core and the second core has an outer leg portion and a middle leg portion formed between the pair of said outer legs. At the locations of the pair of outer legs, the first core and the second core are joined via the bonding resin. At the location of the middle leg, the first core and the second core are not joined by the bonding resin, and a gap is formed between the first core and the second core.

3. The coil device according to claim 1 or 2, characterized in that: The first core and the second core are combined to form an EE core, an EI core, a UU core, or a UI core.

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