Circuit structure

Abstract

To provide a circuit structure having a novel structure capable of reducing the thermal resistance of a heat dissipation path and improving the heat dissipation while ensuring the insulation between a heat radiating unit and a heat radiating target.SOLUTION: A circuit structure 10 includes heat-generating units 12 and 14 that generate heat when energized, a case 24 that accommodates the heat-generating units 12 and 14, a metal plate 18 having a heat radiating unit 26 that is exposed to the outside of the case 24 and thermally contacts an external heat radiating target 29, which is connected to connecting portions 38 and 44 of the heat-generating units 12 and 14, an insulating film 30 that covers the contact surface 34 of the heat radiating unit 26 to the heat radiating target 29, and a heat-conducting filling member 32 arranged between the insulating film 30 and the heat radiating target 29 by thermally contacting the heat radiating unit 26 via the insulating film 30.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a circuit assembly having a heat generating component. [Background technology]

[0002] Conventionally, in a circuit configuration including heat-generating components such as relays and fuses that generate heat when current is applied, a heat dissipation structure for dissipating heat from the heat-generating components may be provided. For example, Patent Document 1 discloses a structure in which a bus bar connected to a relay housed in a case is integrated with a heat sink via an insulating heat conductive sheet, and the end of the heat sink is connected to the housing case. As a result, heat generated by the relay is transferred in the order of the bus bar, the heat conductive sheet, the heat sink, and the housing case, and is dissipated from the housing case to the outside. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-176279 A Summary of the Invention [Problem to be solved by the invention]

[0004] In such a conventional structure, the number of components in the heat dissipation path increases, which increases the thermal resistance. This has led to problems with insufficient heat dissipation, particularly in recent years with high-current devices.

[0005] Therefore, a circuit assembly of a novel structure is disclosed that can reduce the thermal resistance of the heat dissipation path and improve heat dissipation while ensuring insulation between the heat dissipation portion and the heat dissipation target. [Means for solving the problem]

[0006] The circuit assembly according to the present disclosure includes a heat generating component that generates heat when current is applied thereto, a case that accommodates the heat generating component, and The case is formed separately from the case and is housed within the case,a metal plate connected to a connection portion of the heat-generating component and having a heat dissipation portion exposed to the outside of the case and in thermal contact with an external heat dissipation target; an insulating film covering a contact surface of the heat dissipation portion with the heat dissipation target; and a thermally conductive filler member in thermal contact with the heat dissipation portion via the insulating film and disposed between the insulating film and the heat dissipation target, Open It has a mouth part, The heat dissipation portion is exposed to the outside of the case through the opening, The insulating film is fixed to the case around the entire periphery of the opening, thereby sealing the opening, and the case is provided with a plurality of protrusions arranged around the peripheral portion of the insulating film with gaps between them. Effect of the Invention

[0007] According to the circuit assembly of the present disclosure, it is possible to reduce the thermal resistance of the heat dissipation path and improve heat dissipation performance while ensuring insulation between the heat dissipation portion and the heat dissipation target. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a circuit assembly according to a first embodiment. [Diagram 2] FIG. 2 is a plan view of the circuit assembly shown in FIG. 1 with an upper case removed. [Diagram 3] FIG. 3 is an exploded perspective view of the circuit assembly shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a perspective view, seen from the planar side, of a lower case constituting the circuit assembly shown in FIG. [Figure 7] 7 is a perspective view of the lower case shown in FIG. 6, seen from the bottom side. [Figure 8] 8 is an enlarged view of the bottom surface of the lower case shown in FIG. 7, and is a cross-sectional perspective view of a portion corresponding to the VIII-VIII cross section in FIG. [Figure 9] FIG. 9 is a vertical cross-sectional view of a circuit configuration according to another embodiment, and corresponds to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Description of the embodiments of the present disclosure> First, embodiments of the present disclosure will be listed and described. The circuit configuration of the present disclosure comprises: (1) A heat-generating component that generates heat when electricity is passed through it, a case that houses the heat-generating component, a metal plate that is connected to a connection portion of the heat-generating component and has a heat dissipation portion that is exposed to the outside of the case and in thermal contact with an external heat dissipation target, an insulating film that covers the contact surface of the heat dissipation portion with the heat dissipation target, and a heat-conductive filler member that is in thermal contact with the heat dissipation portion via the insulating film and is positioned between the insulating film and the heat dissipation target.

[0010] According to the circuit configuration of the present disclosure, the heat dissipation part of the metal plate connected to the connection part of the heat generating component is exposed to the outside of the case and contacts the external heat dissipation target via the insulating film and the heat conductive filling member. This makes it possible to reduce the number of parts interposed in the heat dissipation path compared to the conventional structure, and to reduce the thermal resistance of the heat dissipation path and improve the heat dissipation. Moreover, the insulation between the heat dissipation part and the heat dissipation target is ensured by using the insulating film. Therefore, compared to the conventional structure in which insulation from the external parts is ensured by a synthetic resin case, the thickness of the member required for insulation can be sufficiently thin, and the reduction of the thermal resistance can be more advantageously achieved. In addition, since the heat conductive filling member is disposed between the insulating film and the heat dissipation target, even if a gap occurs between the contact surfaces of the heat dissipation part and the heat dissipation target due to tolerance or the like, the heat conductive filling member can be interposed between the two to prevent the deterioration of heat transfer due to the gap and to more advantageously improve the heat dissipation. For example, the heat dissipation part may be provided on the metal plate for current flow, or on a metal plate for heat dissipation that is separate from the metal plate for current flow. Note that the heat dissipation part being exposed to the outside of the case means that the heat dissipation part can be in thermal contact with an external heat dissipation target without going through the case.

[0011] The insulating film is not particularly limited as long as it has insulating properties and covers the contact surface of the heat dissipation part with the heat dissipation target, but a film made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytetrafluoroethylene (PTFE), polycarbonate (PC), polyimide (PI), etc. can be advantageously used. The thickness of the insulating film is not particularly limited, but in order to advantageously achieve thermal conductivity from the heat dissipation part to the heat dissipation target, a relatively thin film is preferable, and for example, a film having a thickness of 500 μm or less, more preferably 250 μm or less can be suitably used.

[0012] The thermally conductive filling member may be any member that absorbs wobble caused by the tolerance between the contact surfaces of the heat dissipation portion and the heat dissipation object while conducting heat from the heat dissipation portion to the heat dissipation object, and may be, for example, a composite material in which a thermally conductive filler is filled in a resin such as an epoxy resin or a silicone resin. Examples of the filler that is filled in the resin include alumina (aluminum oxide), boron nitride, aluminum nitride, and silicon nitride. The thermally conductive filling member may be in various forms such as a sheet, gel, or grease.

[0013] (2) It is preferable that the insulating film and the thermally conductive filler member are disposed in different regions.

[0014] An insulating film for ensuring insulation of the heat dissipation part against the heat dissipation target and a heat conductive filler for absorbing wobble between the contact surfaces of the heat dissipation part and the heat dissipation target are provided as separate members. This allows the insulating film and the heat conductive filler to be provided within a necessary range to achieve the functions required for each, and compared to a case where a single member is used for insulation and wobble absorption, it is possible to achieve effects such as improved design freedom and reduced material costs. Note that the arrangement area refers to an area where the insulating film and the heat conductive filler overlap the heat dissipation target when the insulating film and the heat conductive filler are viewed from the overlapping direction on the heat dissipation target, and different arrangement areas include cases where the size or shape of the area where the insulating film overlaps the heat dissipation target and the area where the heat conductive filler overlaps the heat dissipation target are different, or where the positions of the areas are shifted from each other.

[0015] (3) It is preferable that the case has an opening for exposing the heat dissipation portion to the outside, and the opening is sealed with the insulating film.

[0016] In order to expose the heat dissipation portion of the metal plate to the outside, an opening is provided in the case and sealed with an insulating film, which improves the waterproofing of the case having the opening and prevents short-circuiting between the heat dissipation portion and the heat dissipation target due to water entering the case, thereby more effectively ensuring insulation between the heat dissipation portion and the heat dissipation target.

[0017] (4) It is preferable that the insulating film is fixed to the case, and the case is provided with a plurality of protrusions arranged around a peripheral edge of the insulating film with gaps between them.

[0018] By fixing the insulating film to the case, the insulating film covering the mounting surface of the heat dissipation part can be stably held, and the handling can be improved. Furthermore, since a plurality of protrusions are provided around the periphery of the insulating film, the plurality of protrusions make it difficult to access the periphery of the insulating film from the outer periphery of the insulating film. This makes it possible to prevent the peripheral part of the insulating film from being lifted up to peel off the insulating film, and when the opening of the case is sealed with the insulating film, waterproofing inside the case is advantageously ensured. Furthermore, since a plurality of protrusions are provided with gaps between them, air and the like are advantageously discharged from the gaps between the protrusions when the heat conductive filling member is provided, and the problem of air accumulating between the insulating film and the heat conductive filling member, which reduces heat dissipation, is also eliminated.

[0019] The gap between the peripheral edge of the insulating film and the protrusion is set to a size that prevents fingers from entering the gap. The insulating film can be attached to the case by any known method such as adhesion or welding.

[0020] (5) In the above item (4), it is preferable that the case includes an upper case and a lower case, and that the multiple protrusions are each triangular when projected in the assembly direction of the upper case and the lower case, and are arranged so that their width gradually narrows toward the insulating film located on the inside.

[0021] The multiple triangular protrusions are arranged so that the width gradually narrows toward the inside, and the gaps between the protrusions gradually increase toward the inside. This makes it easier to capture air between the insulating film and the filling member, and allows the air to be discharged more efficiently. In addition, the gaps between the protrusions are smallest on the outside, which makes it more effective at preventing fingers from entering the gaps.

[0022] (6) It is preferable that the case includes an upper case and a lower case, the heat-generating component is fixed to at least one of the upper case and the lower case, the lower case has a mounting surface for the heat dissipation target, an opening is provided on the mounting surface, the lower case has a positioning portion for positioning the heat dissipation portion of the metal plate placed in the opening so that it is flush with the mounting surface, the metal plate is provided with a connection portion to the connection portion of the heat-generating component, and a tolerance absorption structure is provided for absorbing tolerances in the connection positions of the connection portions and the connection portions when the heat dissipation portion is positioned by the positioning portion.

[0023] The lower case assembled to the upper case has a mounting surface for a heat dissipation target. The mounting surface is provided with an opening for exposing the heat dissipation portion of the metal plate. The lower case has a positioning portion for positioning the heat dissipation portion so that it is flush with the mounting surface, thereby suppressing or preventing the occurrence of a defect in which a step occurs between the heat dissipation portion and the mounting surface and adversely affects the adhesion of the insulating film. In addition, the connection portion of the metal plate where the heat dissipation portion is positioned on the lower case side needs to be connected to the connection portion of the heat generating component. However, since the circuit assembly has a tolerance absorption structure that absorbs the tolerance of the connection position between the connection portion and the connection portion, the connection portion of the metal plate where the heat dissipation portion is positioned on the lower case can be connected to the connection portion of the heat generating component without any problem. Note that the heat generating component may be fixed to either the upper case or the lower case, but the tolerance absorption effect is more effectively enjoyed when the heat generating component is fixed to the upper case, because the deviation due to the tolerance of each member is likely to be large at the connection position between the connection portion of the heat generating component and the connection portion of the metal plate when the upper case and the lower case are assembled.

[0024] The shape of the positioning portion may be set arbitrarily as long as it can position the lower surface of the heat dissipation portion so as to be flush with the mounting surface of the lower case. For example, a shape in which the lower surface of the heat dissipation portion and the mounting surface are in contact with each other in part or in whole may be preferably used.

[0025] (7) In the above (6), it is preferable that the heat-generating component includes a first heat-generating component, the metal plate includes a metal plate for a first heat-generating component connected to the connection portion of the first heat-generating component, the connection portion of the first heat-generating component and the connection portion of the metal plate for the first heat-generating component are fastened using a first bolt extending in a direction perpendicular to the assembly direction of the upper case and the lower case, a bolt insertion hole having an elongated hole shape extending in the assembly direction of the upper case and the lower case is provided in the fastening portion of the metal plate for the first heat-generating component, a first tolerance absorption structure is formed by the bolt insertion hole, and the tolerance absorption structure includes the first tolerance absorption structure.

[0026] The connection portion of the first heat-generating component and the connection portion of the metal plate for the first heat-generating component are fastened by a bolt extending in a direction perpendicular to the assembly direction of the upper case and the lower case, and the bolt insertion hole provided in the metal plate for the first heat-generating component is made an elongated hole extending in the assembly direction, thereby providing a first tolerance absorption structure with a simple structure.

[0027] (8) In (7) above, it is preferable that the upper case has a top wall and a side wall protruding from the top wall toward the lower case, the lower case has a bottom wall and a peripheral wall protruding from the bottom wall toward the upper case, and at least one of the side wall and the peripheral wall is provided with a working hole through which the first bolt and a tool for fastening the first bolt can be inserted.

[0028] After the upper case is assembled to the lower case, the connection portion of the metal plate for the first heat-generating component, which positions the heat dissipation portion relative to the positioning portion of the lower case, can be bolted to the connection portion of the first heat-generating component from outside the upper case, thereby enabling the positioning of the heat dissipation portion and the lower case and the absorption of tolerances between the connection portions to be achieved with good workability.

[0029] (9) In the above (7) or (8), it is preferable that the first heat-generating component metal plate is bent into an L shape, one end of the first heat-generating component metal plate is the heat dissipation portion extending parallel to the mounting surface of the lower case, and the other end of the first heat-generating component metal plate is the connection portion rising toward the upper case, the mounting surface of the lower case is provided with a slit-shaped insertion hole that allows the connection portion to pass through, and a recess that is connected to the insertion hole and recessed toward the upper case to accommodate the heat dissipation portion, the opening is formed including the insertion hole and the recess, a top plate of the recess forms a positioning portion for the first metal plate that positions the first heat-generating component metal plate, and the positioning portion includes the positioning portion for the first metal plate.

[0030] By making the first metal plate for heat-generating components L-shaped, the opening area of ​​the insertion hole provided on the mounting surface of the lower case can be reduced while the connection portion of the first metal plate for heat-generating components can be inserted into the case. Moreover, by providing a recess connected to the insertion hole and recessed into the upper case, the heat dissipation portion can be accommodated in the recess and the heat dissipation portion and the mounting surface can be made flush with each other. In this case, since the top plate of the recess can form a positioning portion for the first metal plate that makes the heat dissipation portion and the mounting surface flush with each other, the heat dissipation portion can be stably held by the lower case, and further, insulation between the heat dissipation portion and the circuit in the case can be advantageously ensured.

[0031] (10) In any one of (6) to (9) above, the heat-generating component includes a second heat-generating component, and the metal plate includes a metal plate for a second heat-generating component connected to the connection portion of the second heat-generating component, the metal plate for the second heat-generating component having the heat dissipation portion provided on one end side and extending parallel to the mounting surface of the lower case, the connection portion provided on the other end side and positioned closer to the upper case than the heat dissipation portion and extending parallel to the heat dissipation portion, and a linking portion rising from the heat dissipation portion toward the connection portion, and the mounting surface of the lower case has an insertion hole that allows the connection portion and the linking portion to pass through, and a heat dissipation portion that is connected to the insertion hole and recessed toward the upper case and extends parallel to the heat dissipation portion. a recess for accommodating a second metal plate, the opening being formed including the insertion hole and the recess, a positioning portion for a second metal plate that positions the metal plate for the second heat-generating component formed by a top plate of the recess, the positioning portion including the positioning portion for the second metal plate, the connection portion being fastened to the connection portion of the second heat-generating component by a second bolt, a nut to which the second bolt accommodated in the upper case is fastened is held so as to be displaceable in a direction away from the mounting surface of the lower case, thereby forming a second tolerance absorption structure, and it is preferable that the tolerance absorption structure includes the second tolerance absorption structure.

[0032] The lower case assembled to the upper case has a mounting surface for a heat dissipation target. The mounting surface is provided with an opening for exposing the heat dissipation portion of the metal plate for the second heat-generating component. The lower case has a positioning portion for the second metal plate for positioning the heat dissipation portion so that it is flush with the mounting surface, thereby suppressing or preventing the occurrence of a defect in which a step occurs between the heat dissipation portion and the mounting surface and adversely affects the adhesion of the insulating film. In addition, although it is necessary to connect the connection portion of the metal plate for the second heat-generating component, where the heat dissipation portion is positioned on the lower case side, to the connection portion of the second heat-generating component, the circuit assembly has a second tolerance absorbing structure that absorbs the tolerance of the connection position between the connection portion and the connection portion, the connection portion of the metal plate for the second heat-generating component, where the heat dissipation portion is positioned on the lower case, can be connected to the connection portion of the second heat-generating component without any problem.

[0033] (11) In the above (10), it is preferable that the insertion hole has a first region through which the connection portion is permitted to pass and a second region through which the connecting portion is permitted to pass, and a lid portion covering the first region of the insertion hole is removably fixed to the placement surface.

[0034] After fastening the connection portion of the second heat-generating component metal plate to the connection portion of the heat-generating component, the wide insertion hole exposing the connection portion of the second heat-generating component metal plate, which is the live portion, can be covered with the lid, which advantageously achieves measures to prevent electric shock and further improves the waterproofing of the case.

[0035] <Details of the embodiment of the present disclosure> Specific examples of the circuit configuration of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0036] <Embodiment 1> A circuit assembly 10 according to a first embodiment of the present disclosure will be described below with reference to Figs. 1 to 8. The circuit assembly 10 according to the first embodiment is mounted on a vehicle (not shown), such as an electric vehicle or a hybrid vehicle, and supplies and controls electric power from a power source (not shown) such as a battery to a load (not shown) such as a motor. The circuit assembly 10 can be arranged in any orientation, but in the following description, the X direction in the drawings is the forward direction, the Y direction is the leftward direction, and the Z direction is the upward direction. In addition, for multiple identical members, only some of the members may be labeled with reference numerals, and the reference numerals may be omitted for the other members.

[0037] <Circuit construct 10> As shown in Figs. 1 to 3, the circuit assembly 10 includes a fuse 12 as a second heat generating component and a relay 14 as a first heat generating component, which are heat generating components that generate heat when current is applied. The circuit assembly 10 also includes a current carrying bus bar 16 connected to connection parts 38, 44 of the fuse 12 and the relay 14, which will be described later, and a heat dissipation bus bar 18 as a metal plate connected to the connection parts 38, 44 of the fuse 12 and the relay 14. The circuit assembly 10 includes a case 24 consisting of an upper case 20 and a lower case 22, and the fuse 12, the relay 14, the current carrying bus bar 16, and the heat dissipation bus bar 18 are housed in the case 24. The heat dissipation bus bar 18 includes a heat dissipation section 26, which is exposed to the outside of the case 24 through an opening 28 provided in the case 24 and is in thermal contact with a metal case 29, such as the case of a battery pack, which is an external heat dissipation target. That is, the heat dissipation portion 26 being exposed to the outside through the opening 28 of the case 24 means that the heat dissipation portion 26 can thermally contact a heat dissipation target outside the case 24 without going through the case 24 .

[0038] The circuit assembly 10 includes an insulating film 30 that seals the opening 28, and a filler 32 as a thermally conductive filling member. The insulating film 30 covers a contact surface 34 of the heat dissipation section 26 that contacts the housing 29, and is fixed to the case 24. The filler 32 is in thermal contact with the heat dissipation section 26 via the insulating film 30, and is disposed between the insulating film 30 and the housing 29. The heat dissipation section 26 is in thermal contact with the housing 29 via the insulating film 30 and the filler 32. In addition, the housing 29 is indicated by a two-dot chain line in FIGS. 1 to 3.

[0039] In the first embodiment, two relays 14 are provided side by side in the left-right direction, the left relay 14 being the first relay 14a and the right relay 14 being the second relay 14b. The fuse 12 is disposed to the left of the left first relay 14a. Four current-carrying bus bars 16 are provided, which are the first to fourth current-carrying bus bars 16a to 16d in order from the left. Five heat-dissipating bus bars 18 are provided, which are the first to fifth heat-dissipating bus bars 18a to 18e in order from the left. Furthermore, two insulating films 30 are provided side by side in the left-right direction, the left insulating film 30 being the first insulating film 30a and the right insulating film 30 being the second insulating film 30b.

[0040] <Fuse 12, first and second relays 14a, 14b> The fuse 12 includes a fuse body 36 having a substantially rectangular parallelepiped shape. The fuse body 36 is provided with metal connection parts 38, 38 that protrude on both the left and right sides. These connection parts 38, 38 have bolt insertion holes 40, 40 that penetrate in the up and down direction. In the first embodiment, the right bolt insertion hole 40 is an elongated hole whose left-right dimension is larger than its front-rear dimension. This makes it possible to absorb assembly errors and tolerances that occur when assembling the current-carrying bus bar 16 and the like to the fuse 12.

[0041] The first and second relays 14a, 14b each include a relay body 42, 42 having a rectangular parallelepiped shape. A pair of connection parts 44, 44 is provided on the front surface of each relay body 42, spaced apart from each other in the left-right direction. That is, the first relay 14a and the second relay 14b are provided with a total of four connection parts 44, which are the first to fourth connection parts 44a to 44d in order from the left. In other words, the first relay 14a is provided with the first and second connection parts 44a, 44b. The second relay 14b is provided with the third and fourth connection parts 44c, 44d. A partition plate 46 is provided between the first connection part 44a and the second connection part 44b of the first relay 14a, and between the third connection part 44c and the fourth connection part 44d of the second relay 14b, protruding forward to separate the first and second connection parts 44a, 44b, and the second relay 14b.

[0042] Further, each relay body 42 is provided with mounting portions 48 that protrude outward on both the left and right sides. These mounting portions 48 are formed with bolt insertion holes 50 that pass through in the up and down direction.

[0043] <First to fourth current-carrying bus bars 16a to 16d> The first to fourth current-carrying bus bars 16a to 16d are formed by bending a metal plate into a predetermined shape by press working, etc. The material of each of the current-carrying bus bars 16a to 16d is not limited, but copper, copper alloy, aluminum, aluminum alloy, etc. are preferably used.

[0044] The first current-carrying bus bar 16a is a member that is connected to the left connection portion 38 of the fuse 12, and extends in the left-right direction as a whole. The left end of the first current-carrying bus bar 16a is an external connection portion 52, and the right end is a fuse connection portion 54. The external connection portion 52 and the fuse connection portion 54 are formed with bolt insertion holes 56, 58 that penetrate in the up-down direction, which is the plate thickness direction.

[0045] The second energizing busbar 16b is a member that connects the right-side connection portion 38 of the fuse 12 and the first connection portion 44a of the first relay 14a, and extends in the left-right direction as a whole. The left end of the second energizing busbar 16b is a fuse connection portion 60, and a bolt insertion hole 62 is formed therein, penetrating in the up-down direction, which is the plate thickness direction. The right end of the second energizing busbar 16b is a relay connection portion 64, and a bolt insertion hole 66 is formed therein, penetrating in the front-rear direction, which is the plate thickness direction.

[0046] The third energizing busbar 16c is a member that connects the second connection portion 44b of the first relay 14a and the third connection portion 44c of the second relay 14b, and extends in the left-right direction as a whole. Both left and right ends of the third energizing busbar 16c are relay connection portions 68, 68, and bolt insertion holes 70, 70 are formed to pass through in the front-rear direction, which is the plate thickness direction. In addition, a rectangular external connection portion 72 that protrudes forward is provided at the upper end of the central portion in the left-right direction of the third energizing busbar 16c, and a bolt insertion hole 74 is formed to pass through in the up-down direction, which is the plate thickness direction.

[0047] The fourth energizing busbar 16d is a member connected to the fourth connection portion 44d of the second relay 14b, and extends in the left-right direction as a whole. The left end of the fourth energizing busbar 16d is a relay connection portion 76, and a bolt insertion hole 78 is formed therethrough in the front-rear direction, which is the plate thickness direction. The right end of the fourth energizing busbar 16d is provided with a rectangular external connection portion 80 that protrudes forward, and a bolt insertion hole 82 is formed therethrough in the up-down direction, which is the plate thickness direction.

[0048] <First to fifth heat dissipation bus bars 18a to 18e> The first to fifth heat dissipation bus bars 18a to 18e are formed by bending a metal plate into a predetermined shape by pressing, etc. The material of each of the heat dissipation bus bars 18a to 18e is not limited, but the same material as the current-carrying bus bars 16 (the first to fourth current-carrying bus bars 16a to 16d) can be used.

[0049] The first heat dissipation busbar 18a is a member connected to the left connection portion 38 of the fuse 12 (second heat generating component) and extends in the left-right direction as a whole. That is, among the metal plates (the first to fifth heat dissipation busbars 18a to 18e), the first heat dissipation busbar 18a is a metal plate for the second heat generating component connected to the second heat generating component (fuse 12). The left end portion, which is one end side of the first heat dissipation busbar 18a, is the heat dissipation portion 26 (the first heat dissipation portion 26a) and spreads in the horizontal direction (XY plane) with a predetermined left-right dimension. In addition, the right end portion, which is the other end side of the first heat dissipation busbar 18a, is the fuse connection portion 84, which is a connection portion to the connection portion 38, and is located above the first heat dissipation portion 26a (on the upper case 20 side) and spreads in the horizontal direction parallel to the first heat dissipation portion 26a. The fuse connection portion 84 is formed with a bolt insertion hole 86 penetrating in the up-down direction, which is the plate thickness direction. The first heat dissipation portion 26a and the fuse connection portion 84 are connected by a connection portion 87 that extends in the vertical direction, and the connection portion 87 rises from the right end of the first heat dissipation portion 26a toward the left end of the fuse connection portion 84.

[0050] The second to fifth heat dissipation busbars 18b to 18e are members connected to the first to fourth connection parts 44a to 44d of the first and second relays 14a and 14b (first heat generating components). That is, among the metal plates (the first to fifth heat dissipation busbars 18a to 18e), the second to fifth heat dissipation busbars 18b to 18e are metal plates for the first heat generating components connected to the first and second relays 14a and 14b. The second to fifth heat dissipation busbars 18b to 18e are bent into an L-shape as a whole, and each has a heat dissipation section 26 (second to fifth heat dissipation sections 26b to 26e) that expands in the horizontal direction (XY plane) at one end. The other ends of the second to fifth heat dissipation busbars 18b to 18e are relay connection parts 88 that are connection parts to the first to fourth connection parts 44a to 44d. Then, each relay connection portion 88 rises upward (toward the upper case 20) from the front end of the second to fifth heat dissipation portions 26b to 26e. As described below, each relay connection portion 88 is fastened with a bolt to the first to fourth connection portions 44a to 44d together with the relay connection portions 64, 68, and 76 of the second to fourth current-carrying bus bars 16b to 16d. That is, each relay connection portion 88 is a fastening portion of the second to fifth heat dissipation bus bars 18b to 18e for a first bolt 132, described below.

[0051] Each relay connection portion 88 is formed with a bolt insertion hole 90 penetrating in the front-rear direction, which is the plate thickness direction. In the first embodiment, the bolt insertion hole 90 extends in the up-down direction (the assembly direction of the upper case 20 and the lower case 22) and has an elongated hole shape with the up-down dimension being larger than the left-right dimension. As described later, the second to fifth heat dissipation portions 26b to 26e of the second to fifth heat dissipation busbars 18b to 18e are received in the second to fifth recesses 108b to 108e and positioned by the second to fifth positioning portions 110b to 110e. In this state, the bolt insertion hole 90 can absorb the tolerance of the connection portions (relay connection portions 88) of the first to fourth connection portions 44a to 44d of the first and second relays 14a, 14b and the second to fifth heat dissipation busbars 18b to 18e. Therefore, in embodiment 1, as one of the tolerance absorption structures provided in the circuit structure 10, a first tolerance absorption structure that absorbs the tolerance of the connection positions of the connection sites (relay connection portion 88) in the second to fifth heat dissipation busbars 18b to 18e and the first to fourth connection portions 44a to 44d is formed by the bolt insertion hole 90.

[0052] <Upper Case 20> The upper case 20 is made of synthetic resin, and as shown in FIG. 3, has a box shape that is open downward and long in the left-right direction as a whole. That is, the upper case 20 has a generally rectangular top wall 92 that extends in the left-right direction as a whole. A side wall 94 that protrudes downward (toward the lower case 22) is provided on the outer peripheral edge of the top wall 92. A plurality of opening windows 96 that penetrate the top wall 92 in the plate thickness direction (up-down direction) are formed at the left end and right side portion. These opening windows 96 are formed at positions corresponding to the external connection parts 52, 72, 80 of the first, third, and fourth current-carrying bus bars 16a, 16c, 16d. As a result, in the assembled circuit assembly 10, the external connection parts 52, 72, 80 are exposed to the outside through the opening windows 96. In addition, a plurality of opening windows 98 that open downward and penetrate the side wall 94 in the plate thickness direction (front-rear direction) are formed in the front wall portion of the side wall 94. These opening windows 98 are formed at positions corresponding to the first to fourth connection portions 44a to 44d of the first and second relays 14a and 14b.

[0053] A nut 99 (see FIG. 5) is attached to the lower surface of the top wall 92 at a position corresponding to the bolt insertion hole 40 provided in the connection portion 38 of the fuse 12 and the bolt insertion hole 50 provided in the mounting portion 48 of the first and second relays 14a, 14b. In the first embodiment, an upper portion of the nut 99 protrudes toward the outer periphery, and an elastically deformable claw portion is provided on the lower surface of the top wall 92. The claw portion is engaged with the protruding portion of the nut 99, so that the nut 99 is attached to the top wall 92. A gap S (see FIG. 5) is provided between the top wall 92 and the nut 99 in the vertical direction, and the nut 99 is attached to the top wall 92 with a certain degree of wobble. In an initial state before a second bolt 130 described later is fastened to the nut 99, the gap S is maximized and the nut 99 is at the end of its downward displacement.

[0054] 5, the connection portion 38 of the fuse 12, the fuse connection portion 54 of the first current-carrying busbar 16a, and the fuse connection portion 84 of the first heat-dissipation busbar 18a are overlapped with the nut 99. At this time, the nut 99 is displaced upward (in a direction away from the mounting surface 107 described later), so that the tolerance of each member is absorbed. That is, as described later, the first heat-dissipating portion 26a of the first heat-dissipation busbar 18a is accommodated in the first recess 108a and positioned in the first positioning portion 110a. In this state, the nut 99 is displaceable in a direction away from the mounting surface 107, so that the tolerance of the connection position of the connection portion 38 of the fuse 12 and the connection portion (fuse connection portion 84) of the first heat-dissipation busbar 18a can be absorbed. Therefore, in embodiment 1, as another tolerance absorption structure provided in the circuit structure 10, a second tolerance absorption structure is configured in which the nut 99 is displaceable in a direction away from the mounting surface 107, absorbing the tolerance of the connection position of the connection site (fuse connection portion 84) in the first heat dissipation busbar 18a and the connection portion 38.

[0055] The method of fixing the nut 99 to the underside of the top wall 92 is not limited to the above-mentioned concave-convex fitting, and may be welding, adhesion, press fitting, insert molding, etc. In this case, the gap S between the top wall 92 and the nut 99 is not essential, and the nut 99 may be fixed to the top wall 92 so as not to be displaceable.

[0056] <Lower Case 22> The lower case 22 is made of synthetic resin, and as shown in FIG. 6, is generally open upward and has a box shape that is long in the left-right direction. That is, the lower case 22 has a bottom wall 100 that is generally rectangular and extends in the left-right direction. A peripheral wall 102 that protrudes upward is provided on the outer peripheral edge of the bottom wall 100. A plurality of support parts 104 that protrude upward are provided on the left end and right side of the bottom wall 100. These support parts 104 are formed at positions corresponding to the external connection parts 52, 72, 80 of the first, third, and fourth current-carrying bus bars 16a, 16c, 16d. As a result, in the assembled circuit assembly 10, the external connection parts 52, 72, 80 are supported from below by the support parts 104. In addition, a nut 106 is fixed to the upper end of each support part 104. The method of fixing the nut 106 to the support portion 104 can be the same as the method of fixing the nut 99 to the lower surface of the top wall 92 described above.

[0057] 4, 5, etc., lower case 22 is placed on housing 29 via insulating film 30 (first and second insulating films 30a, 30b) and filler 32. Therefore, the lower surface of bottom wall 100 of lower case 22 is mounting surface 107 for mounting a heat dissipation target (housing 29) that extends in the horizontal direction (XY plane). Then, as shown in FIGS. 7, 8, etc., recesses 108 (first to fifth recesses 108a to 108e) that accommodate heat dissipation portions 26a to 26e of heat dissipation busbars 18a to 18e, as described below, are formed on mounting surface 107.

[0058] That is, the first to fifth recesses 108a to 108e are substantially equal to or slightly larger than the first to fifth heat dissipation sections 26a to 26e in a plan view. The first to fifth recesses 108a to 108e are bottomed recesses that open downward, and the top plates of the recesses 108a to 108e are formed by the bottom wall 100 of the lower case 22. The depth dimensions of the first to fifth recesses 108a to 108e are substantially equal to the plate thickness dimensions of the first to fifth heat dissipation sections 26a to 26e. This allows the placement surface 107 to be flush with the lower surfaces of the first to fifth heat dissipation sections 26a to 26e when the first to fifth recesses 108a to 108e are accommodated in the first to fifth recesses 108a to 108e as described below.

[0059] In the first embodiment, the plate thickness of the bottom wall 100 of the lower case 22 is generally constant throughout. In the portions where the recesses 108a-108e are provided, the top surface of the bottom wall 100 protrudes upward from the other portions and is recessed toward the upper case 20 by the depth of each of the recesses 108a-108e. The portions that form the top plates of the recesses 108a-108e and are located higher than the other portions on the top surface of the bottom wall 100 are positioning portions 110 (first positioning portions 110a-fifth positioning portions 110e) that position the heat dissipation portions 26a-26e of the heat dissipation busbars 18a-18e as described below. In particular, the first positioning portion 110a is a second metal plate positioning portion that positions the second heat-generating component metal plate (first heat dissipation busbar 18a). The second to fifth positioning portions 110b to 110e are first metal plate positioning portions that position the first heat generating component metal plate (the second to fifth heat dissipation bus bars 18b to 18e).

[0060] 4 and 5, the bottom wall 100 is provided with an insertion hole 111 penetrating in the up-down direction. The insertion hole 111 opens to the upper and lower surfaces (mounting surface 107) of the bottom wall 100. In the mounting surface 107, the insertion hole 111 is connected to the recesses 108. That is, the bottom wall 100 is provided with first to fifth insertion holes 111a to 111e connected to the first to fifth recesses 108a to 108e, respectively. The first to fifth recesses 108a to 108e and the first to fifth insertion holes 111a to 111e form openings 28 (first to fifth openings 28a to 28e) in the mounting surface 107, which expose the first to fifth heat dissipation portions 26a to 26e of the first to fifth heat dissipation bus bars 18a to 18e to the outside. In other words, the first to fifth openings 28a to 28e are partially bottomed openings (first to fifth recesses 108a to 108e) having a bottom (top plate). The remaining portions are bottomless openings (first to fifth insertion holes 111a to 111e) that penetrate the bottom wall 100. In the first embodiment, the second to fifth insertion holes 111b to 111e are slit-shaped with a left-right dimension larger than a front-rear dimension.

[0061] Specifically, a first insertion hole 111a is formed adjacent to the right side of the first recess 108a. In addition, second to fifth insertion holes 111b to 111e are formed adjacent to the front of the second to fifth recesses 108b to 108e. This first insertion hole 111a is larger than the fuse connection portion 84 and the coupling portion 87 of the first heat dissipation busbar 18a in a plan view (up-down projection). As shown in FIG. 5, the first insertion hole 111a includes a first region 84a through which the fuse connection portion 84 of the first heat dissipation busbar 18a is allowed to pass, and a second region 87a through which the coupling portion 87 is allowed to pass. The second to fifth insertion holes 111b to 111e are larger than the relay connection portions 88 of the second to fifth heat dissipation busbars 18b to 18e in a plan view.

[0062] In the first embodiment, the opening dimension of the lower opening of the first insertion hole 111a is made larger, and a lid accommodating portion 112 for accommodating a lid 128 (described later) is formed on the mounting surface 107. Specifically, the opening of the lid accommodating portion 112 is made larger on the right side and on both the front and rear sides compared to the first insertion hole 111a, and the left side of the lid accommodating portion 112 communicates with the first recess 108a. That is, the lid accommodating portion 112 opens downward, and has a bottom portion 114 formed of the bottom wall 100 of the lower case 22 on the right side and on both the front and rear sides.

[0063] Furthermore, in the first embodiment, as shown in FIG. 8, a protrusion 116 that protrudes downward is formed on the lower surface (mounting surface 107) of the bottom wall 100 around the entire circumference of the first opening 28a. Also, the protrusion 116 is formed around the entire circumference of the second to fifth openings 28b to 28e. In the first embodiment, the multiple protrusions 116 are provided spaced apart from each other in the circumferential direction. A gap 118 is formed between the protrusions 116, 116 adjacent to each other in the circumferential direction. In particular, in the first embodiment, the protrusions 116 are triangular in plan view (projected in the up-down direction), and the protrusions 116 are arranged so that the width gradually narrows toward the first opening 28a and the second to fifth openings 28b to 28e located on the inside. As a result, the gap 118 between the protrusions 116, 116 gradually widens from the outside toward the inside. The size of the gap 118 between the protrusions 116, 116 is not limited, but it is preferably large enough that, for example, the user's fingers cannot be inserted therein.

[0064] <Case 24> The upper case 20 and the lower case 22 are assembled together to form the case 24. In the first embodiment, the opening of the upper case 20 is larger than the opening of the lower case 22, and the upper case 20 is assembled from above so as to cover the opening of the lower case 22 from the outside. That is, in the first embodiment, the assembly direction of the upper case 20 and the lower case 22 is the up-down direction. The method of fixing the upper case 20 and the lower case 22 is not limited. For example, the upper case 20 and the lower case 22 may be provided with recesses and protrusions that fit together, and the upper case 20 and the lower case 22 may be fixed together by the recess-protrusion fit between the recesses and protrusions.

[0065] In the first embodiment, four opening windows 98 are formed in the front wall portion of the side wall 94 of the upper case 20, and when the upper case 20 and the lower case 22 are assembled, the lower openings of these opening windows 98 are closed by the peripheral wall 102 of the lower case 22. As a result, the case 24 is formed with rectangular working holes 120 (see FIG. 4) penetrating in the thickness direction at the positions where the opening windows 98 are formed. In the first embodiment, caps 122 that close these working holes 120 are attached to the case 24. In particular, in the first embodiment, four working holes 120 are provided, and the caps 122 are adapted to close two adjacent working holes 120, and two caps 122 are attached to the case 24.

[0066] The cap 122 includes a rectangular flat base plate 124. The base plate 124 is provided with a plurality of claws 126 protruding from one side in the plate thickness direction. The cap 122 is attached to the case 24 by overlapping the base plate 124 with the side wall 94 of the upper case 20 and engaging the claws 126 with the opening edge of the working hole 120. Specifically, the claws 126 are engaged with both the upper and lower opening edges of the working hole 120 and with either the left or right opening edge. That is, the upper claws 126 are engaged with the upper edge of the opening window 98, and the lower claws 126 are engaged with the opening edge of the peripheral wall 102 of the lower case 22.

[0067] In the first embodiment, the first insertion hole 111a opening in the lower surface (mounting surface 107) of the case 24 (lower case 22) is closed by a rectangular flat lid 128. The lid 128 is formed to be larger than the first insertion hole 111a and smaller than the lid accommodating portion 112 in a plan view (projected in the up-down direction). As a result, the lower opening of the first insertion hole 111a is closed by abutting the outer periphery of the lid 128 against the bottom portion 114 of the lid accommodating portion 112 to accommodate the lid 128 in the lid accommodating portion 112. Specifically, as described below, the fuse connection portion 84 and the connecting portion 87 of the first heat dissipation busbar 18a are inserted into the inside of the case 24 (lower case 22) through a first region 84a and a second region 87a of the first insertion hole 111a, and the first heat dissipation portion 26a of the first heat dissipation busbar 18a extends from the inside to the outside of the case 24 (lower case 22) through the connecting portion 87. That is, the lid portion 128 is fixed so as to cover the first region 84a of the first insertion hole 111a.

[0068] The plate thickness dimension of the lid portion 128 is set to be approximately equal to the depth dimension of the lid portion accommodating portion 112 (i.e., the vertical dimension from the mounting surface 107 to the bottom portion 114 of the lid portion accommodating portion 112). As a result, when the lid portion 128 is accommodated in the lid portion accommodating portion 112 as described below, the lower surfaces of the mounting surface 107 and the first heat dissipation portion 26a are flush with the lower surface of the lid portion 128.

[0069] The method of fixing the lid 128 to the lid accommodating section 112 may be to simply place the lid 128 on the bottom portion 114 of the lid accommodating section 112 and attach the first insulating film 30a from the outside, as described below. Alternatively, for example, a protrusion protruding toward the inner periphery may be provided at the lower opening of the lid accommodating section 112, and the lid 128 may ride over this protrusion to be accommodated in the lid accommodating section 112, so that the lid 128 is held in a state of being accommodated in the lid accommodating section 112. When removing the lid 128 from the lid accommodating section 112, the first insulating film 30a may be peeled off, or the first insulating film 30a may be peeled off and then the lid 128 may ride over the protrusion at the lower opening of the lid accommodating section 112. In short, the lid 128 may be detachably fixed to the lid accommodating section 112 provided on the placement surface 107.

[0070] <First and second insulating films 30a, 30b> As shown in Figs. 4 and 5, the first and second insulating films 30a and 30b are fixed to the lower surface of the case 24 (lower case 22). The first and second insulating films 30a and 30b are made of synthetic resin having waterproof and electrical insulating properties, and are rectangular. Specifically, as shown by the two-dot chain line in Figs. 7 and 8, the first insulating film 30a is formed to a size that can cover the first opening 28a. The second insulating film 30b is formed to a size that can cover the second to fifth openings 28b to 28e. The thickness of the first and second insulating films 30a and 30b is not limited. The first and second insulating films 30a and 30b are preferably set to 500 µm or less, for example, and more preferably set to 250 µm or less. By setting the thickness of the first and second insulating films 30a and 30b within the above range, good heat transfer properties are exhibited. In addition, in FIGS. 4 and 5, the thickness dimensions of the first and second insulating films 30a, 30b are exaggerated for ease of viewing.

[0071] The material of the first and second insulating films 30a and 30b may be, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytetrafluoroethylene (PTFE), polycarbonate (PC), polyimide (PI), etc. Specifically, for example, "Kapton (registered trademark)" manufactured by DuPont-Toray Co., Ltd. may be used.

[0072] In the first embodiment, the first and second insulating films 30a, 30b are larger than the first opening 28a and the second to fifth openings 28b to 28e over the entire periphery, that is, in both the front-rear direction and the left-right direction, in a plan view (projection in the up-down direction). The first insulating film 30a is formed to a size that fits within the inside of a plurality of protrusions 116 provided around the first opening 28a on the lower surface (mounting surface 107) of the lower case 22. The second insulating film 30b is formed to a size that fits within the inside of a plurality of protrusions 116 provided around the second to fifth openings 28b to 28e. In other words, the plurality of protrusions 116 are arranged around the periphery of each of the first insulating film 30a and the second insulating film 30b. The size of the opposing gap between the first insulating film 30a and the protrusion 116, and the opposing gap between the second insulating film 30b and the protrusion 116 are not limited, but it is preferable that they be large enough that, for example, the user's fingers cannot be inserted therethrough.

[0073] The first and second insulating films 30a, 30b may be fixed to the lower surface (mounting surface 107) of the lower case 22 by, for example, having an adhesive surface on the first and second insulating films 30a, 30b themselves and attaching them to the mounting surface 107. Alternatively, an adhesive may be applied to at least one of the mounting surface 107 (including the lower surfaces of the first to fifth heat dissipation parts 26a to 26e and the lower surface of the lid part 128) and the first and second insulating films 30a, 30b, and then attached to the mounting surface 107. The above-mentioned adhesive surface or adhesive is preferably provided over the entire surface of the first and second insulating films 30a, 30b. In addition, when waterproofing is obtained by such an adhesive, the first and second insulating films 30a, 30b themselves do not need to have waterproofing. The method for fastening the first and second insulating films 30a, 30b to the mounting surface 107 of the lower case 22 is not limited, and any well-known method such as adhesion or welding may be used.

[0074] In the first embodiment, the size of the first and second insulating films 30a, 30b is set to be relatively large compared to the first heat dissipation section 26a and the second to fifth heat dissipation sections 26b to 26e. Specifically, for example, the left-right length dimension L (see FIGS. 2 and 8) of the second insulating film 30b, which is superimposed on and attached to the lower surface (mounting surface 107) of the lower case 22 outside the left-right direction of the second to fifth heat dissipation sections 26b to 26e, is set to be relatively large. The specific length of this length dimension L is not limited, but can be, for example, 11 mm to 12 mm. This allows the creepage distance between the second heat dissipation bus bar 18b and the housing 29 to be set large, and unintended electrical short circuits can be prevented.

[0075] <Filler 32> The filler 32 may be any member that has heat conductivity (heat dissipation properties) and is filled in the space between the case 24 (lower case 22) and the first and second insulating films 30a, 30b and the housing 29. That is, the first to fifth heat dissipation sections 26a to 26e are in thermal contact with the housing 29 via the first and second insulating films 30a, 30b and the filler 32 arranged on the first and second insulating films 30a, 30b side. Therefore, the lower surfaces of the first to fifth heat dissipation sections 26a to 26e are contact surfaces 34 with the housing 29, and these contact surfaces 34 are covered by the first and second insulating films 30a, 30b.

[0076] The filler 32 is formed of, for example, synthetic resin having electrical insulation. In the first embodiment, the filler 32 is separate from the first and second insulating films 30a, 30b, and preferably has, for example, elasticity. This allows the filler 32 to absorb the unevenness caused by the protrusion 116 provided on the lower surface (mounting surface 107) of the lower case 22 and the first and second insulating films 30a, 30b. The filler 32 can be understood as, for example, a material generally called an elastic material or a filler, and can be, for example, a conventionally known thermal interface material or a gap filler having heat dissipation properties. For example, a composite material in which a thermally conductive filler is filled in a resin such as an epoxy resin or a silicone resin is used as the filler for the thermally conductive filler filled in the resin. For example, alumina (aluminum oxide), boron nitride, aluminum nitride, silicon nitride, etc. are used as the thermally conductive filler to be filled in the resin. Note that the thermally conductive filler can be in various forms such as a sheet, a gel, or a grease.

[0077] In the first embodiment, a gap filler is used as the filler 32, which is in a grease-like form when applied to the lower case 22 and the lower surfaces of the first and second insulating films 30a, 30b, and hardens into a sheet-like form when heated (for example, at room temperature). By using such a filler 32, air is advantageously prevented from entering between the lower case 22 or the first and second insulating films 30a, 30b and the filler 32, and between the filler 32 and the housing 29, thereby improving heat dissipation. For example, the "SDP series" manufactured by Shin-Etsu Chemical Co., Ltd. can be used as such a filler 32. The filler 32 may be designed to exhibit a certain degree of elasticity before and after assembly.

[0078] When the filler 32 is, for example, grease-like as in the first embodiment, it is indefinitely shaped without a specific shape before assembly, and FIG. 3 shows the rectangular plate-shaped filler 32 after hardening. In FIG. 3, the filler 32 is shown with lines corresponding to the first and second insulating films 30a, 30b, the protrusion 116, and the outer peripheral edge of the lower case 22, but when the filler 32 before assembly is grease-like, the lines are merely shown as the lower surface of the lower case 22 and the first and second insulating films 30a, 30b transferred to the hardened filler 32. The hardening of the filler 32 may be by heat (for example, room temperature or higher or lower than room temperature) or by ultraviolet light (UV), for example. However, the filler 32 is not limited to the above-mentioned form, and may be formed into a rectangular plate shape having a certain degree of strength in the initial state before assembly, for example, by being formed of rubber, elastomer, or the like. In this case, in the initial state, recesses corresponding to the outer peripheral edge portion and protrusion 116 of lower case 22 and first and second insulating films 30a, 30b may be formed in advance. Note that the shape of filler 32 (or the shape of filler 32 after hardening) is not limited to a rectangular plate shape.

[0079] In the first embodiment, the filler 32 is provided between the lower case 22 and the housing 29 over an area larger than that of the lower case 22 in a plan view. That is, in the first embodiment, the arrangement areas of the first and second insulating films 30a, 30b are different from that of the filler 32. Specifically, in a plan view (a vertical projection, viewed in the direction of overlapping with the housing 29), the filler 32 is arranged over an area larger than that of the first and second insulating films 30a, 30b.

[0080] <Assembly process of the circuit structure 10> Next, a specific example of the process of assembling the circuit assembly 10 will be described. Note that the process of assembling the circuit assembly 10 is not limited to the following description.

[0081] First, the upper case 20, the fuse 12, the first and second relays 14a, 14b, the first to fourth current-carrying bus bars 16a-16d, and the first to fifth heat-dissipating bus bars 18a-18e are prepared. After that, the first and second relays 14a, 14b are placed on the top wall 92 of the upper case 20 that has been turned upside down, and the second bolts 130 are inserted into the bolt insertion holes 50 of the mounting portions 48 and fastened to the nuts 99. This fixes the first and second relays 14a, 14b to the upper case 20. In addition, the fuse 12 and the first to fourth current-carrying bus bars 16a-16d are placed on the top wall 92. Then, the right bolt insertion hole 40 in the fuse 12 and the bolt insertion hole 62 of the fuse connection portion 60 in the second current-carrying bus bar 16b are aligned with each other, and the second bolt 130 is inserted through these bolt insertion holes 40, 62 and fastened to the nut 99.

[0082] Next, the lower case 22 is attached through the upper opening of the inverted upper case 20. The upper case 20 and the lower case 22 are fixed together by a recess-projection fitting or the like (not shown). This forms the case 24. The first to fifth heat dissipation bus bars 18a to 18e are then attached to the bottom wall 100 of the lower case 22 located on the upper side. Specifically, the fuse connection portion 84 of the first heat dissipation bus bar 18a and the relay connection portion 88 of the second to fifth heat dissipation bus bars 18b to 18e are inserted into the case 24 through the first to fifth insertion holes 111a to 111e provided in the bottom wall 100 of the lower case 22. At this time, the first to fifth heat dissipation portions 26a to 26e of the first to fifth heat dissipation busbars 18a to 18e are accommodated in the first to fifth recesses 108a to 108e provided in the bottom wall 100 of the lower case 22. That is, the first to fifth heat dissipation portions 26a to 26e are brought into contact with the first to fifth positioning portions 110a to 110e to position the first to fifth heat dissipation busbars 18a to 18e with respect to the lower case 22. As a result, the mounting surface 107 and the lower surfaces (upper surfaces because they are turned upside down when assembled) of the first to fifth heat dissipation portions 26a to 26e are flush with each other. Here, among the positioning portions 110 (the first to fifth positioning portions 110a to 110e), the first positioning portion 110a that positions the first heat dissipation busbar 18a (metal plate for second heat-generating component) is a positioning portion for the second metal plate. Among the positioning portions 110 (first to fifth positioning portions 110a to 110e), the second to fifth positioning portions 110b to 110e which position the second to fifth heat dissipation busbars 18b to 18e (first heat-generating component metal plate) are the first metal plate positioning portions.

[0083] Furthermore, by inserting the fuse connection portion 84 and the relay connection portion 88 into the case 24, the fuse connection portion 54 of the first current-carrying busbar 16a and the fuse connection portion 84 of the first heat-dissipation busbar 18a are overlapped in the up-down direction. This aligns the left bolt insertion hole 40 of the fuse 12 with the bolt insertion holes 58, 86 provided in both fuse connection portions 54, 84. Furthermore, the relay connection portions 64, 68, 76 of the second to fourth current-carrying busbars 16b to 16d and the relay connection portion 88 of the second to fifth heat-dissipation busbars 18b to 18e are overlapped in the front-rear direction. As a result, the first to fourth connection portions 44a to 44d of the first and second relays 14a and 14b, the bolt insertion holes 66, 70, and 78 of the respective relay connection portions 64, 68, and 76, and the bolt insertion hole 90 of the respective relay connection portion 88 are aligned with one another.

[0084] Thereafter, the second bolt 130 extending in the up-down direction (the assembly direction of the upper case 20 and the lower case 22) and a fastening tool (not shown) are inserted into the first insertion hole 111a. Then, the second bolt 130 is inserted into each of the aligned bolt insertion holes 40, 58, 86 and fastened to the nut 99. This fixes the fuse 12 to the upper case 20, and fastens the first current-carrying bus bar 16a and the first heat-dissipating bus bar 18a together with the connection portion 38 of the fuse 12 by the bolt fastening. Also, the first bolt 132 extending in the front-rear direction (the direction perpendicular to the assembly direction of the upper case 20 and the lower case 22) and a fastening tool (not shown) are inserted through the working hole 120 provided in the front of the case 24. Then, the first bolts 132 are inserted through the first to fourth connection parts 44a to 44d and the bolt insertion holes 66, 70, 78, and 90 that are aligned with each other, and fastened to the first to fourth connection parts 44a to 44d. As a result, the second to fourth current-carrying busbars 16b to 16d and the second to fifth heat-dissipating busbars 18b to 18e are fastened together to the first to fourth connection parts 44a to 44d of the first and second relays 14a and 14b by bolt fastening. In this manner, the first to fourth current-carrying busbars 16a to 16d and the first to fifth heat-dissipating busbars 18a to 18e are connected to the connection parts 38, 44a to 44d of the fuse 12 and the first and second relays 14a and 14b.

[0085] After the first bolt 132 is fastened, the cap 122 is attached to the working hole 120 to close the working hole 120, which is an opening in the case 24. After the second bolt 130 is fastened through the first insertion hole 111a, the lid 128 is attached to the lid accommodating portion 112 to close the first insertion hole 111a. Since the case 24 is turned upside down, the lid 128 will not fall off the lid accommodating portion 112 simply by placing the lid 128 on the bottom portion 114 of the lid accommodating portion 112. However, for example, a protrusion for preventing the lid 128 from falling off may be provided on the edge of the opening of the lid accommodating portion 112. The lid 128 can be attached to the edge of the opening of the lid accommodating portion 112 so as to ride over this protrusion.

[0086] Next, a first insulating film 30a is attached to the bottom wall 100 of the lower case 22 so as to cover the first heat dissipation portion 26a and the lid portion 128, thereby sealing the first opening 28a. Also, a second insulating film 30b is attached to cover the second to fifth heat dissipation portions 26b to 26e, thereby sealing the second to fifth openings 28b to 28e. Next, a filler 32 is provided on the bottom wall 100 of the lower case 22 and the first and second insulating films 30a, 30b. Thereafter, the entire structure is turned upside down to complete the circuit assembly 10 of the first embodiment.

[0087] In the first embodiment, the filler 32 is in a grease-like form before assembly, and is applied to the bottom wall 100 of the lower case 22 and the lower surfaces of the first and second insulating films 30a, 30b, and then hardened while pressed against the upper surface of the metal housing 29. As a result, the first to fifth heat dissipation sections 26a to 26e are in thermal contact with the housing 29 via the first and second insulating films 30a, 30b and the filler 32. In addition, by applying the grease-like filler 32 to the case 24 and hardening it while pressed against the housing 29, it is possible to prevent air from entering between the lower case 22 and the first and second insulating films 30a, 30b and the filler 32, and between the filler 32 and the housing 29. Therefore, in the first embodiment, when the circuit assembly 10 is fixed to the housing 29, the lower surface of the lower case 22 is located slightly lower than the upper surface of the filler 32 (see FIG. 4, etc.).

[0088] In the circuit assembly 10 assembled by the above-mentioned process, the external connection parts 52, 72, 80 of the first, third, and fourth current-carrying bus bars 16a, 16c, 16d are exposed to the outside through the opening window 96 of the case 24 (upper case 20). Then, terminals provided at the ends of the external electric wires are overlapped with the external connection parts 52, 72, 80, and bolts (not shown) are inserted into the bolt insertion holes 56, 74, 82 of each of the external connection parts 52, 72, 80 and fastened to the nuts 106. This electrically connects the external electric wires to the circuit assembly 10.

[0089] When electricity is applied to the fuse 12 and the first and second relays 14a, 14b, the fuse 12 and the first and second relays 14a, 14b generate heat. The heat generated in the fuse 12 and the first and second relays 14a, 14b is transferred to the first to fifth heat dissipation sections 26a-26e in the first to fifth heat dissipation bus bars 18a-18e. The heat is dissipated to the outside through the housing 29 that is in thermal contact with the first to fifth heat dissipation sections 26a-26e via the first and second insulating films 30a, 30b and the filler 32.

[0090] Therefore, in the circuit assembly 10 of the first embodiment, the first to fifth heat dissipation sections 26a to 26e can be thermally in contact with the housing 29 via the first and second insulating films 30a, 30b and the filler 32, without the need for a synthetic resin case as in the conventional structure. As a result, the first and second insulating films 30a, 30b provide electrical insulation between the first to fifth heat dissipation sections 26a to 26e and the housing 29. In addition, the number of components on the heat dissipation path from the first to fifth heat dissipation sections 26a to 26e to the housing 29 can be reduced, and the length of the heat dissipation path can be kept short, improving the heat dissipation efficiency. Furthermore, the filler 32 absorbs irregularities caused by the lower surface of the lower case 22 and the first and second insulating films 30a, 30b. As a result, air is prevented from entering between the lower case 22, the first and second insulating films 30a, 30b, and the housing 29. As a result, the heat dissipation efficiency can be further improved.

[0091] In particular, in the first embodiment, the first and second insulating films 30a, 30b and the filler 32 are separate from each other, so that the first and second insulating films 30a, 30b with good insulation efficiency and the filler 32 with good heat transfer efficiency can be used. Therefore, both the insulation efficiency and the heat transfer efficiency can be improved. Furthermore, the first and second insulating films 30a, 30b are provided to be larger than the first heat dissipation section 26a and the second to fifth heat dissipation sections 26b to 26e, respectively, in a plan view. Therefore, good electrical insulation is exhibited between the first to fifth heat dissipation sections 26a to 26e and the housing 29.

[0092] Since the first and second insulating films 30a, 30b and the filler 32 are arranged in different regions, the sizes and shapes of the first and second insulating films 30a, 30b and the filler 32 can be set according to the required electrical insulation and thermal conductivity. This provides the effects of improving design freedom and reducing material costs.

[0093] Since the case 24 has the first to fifth openings 28a to 28e that expose the first to fifth heat dissipation parts 26a to 26e to the outside, the amount of resin required for the case 24 can be reduced. In addition, the first and second insulating films 30a, 30b are provided over an area wider than the first to fifth openings 28a to 28e in a plan view to seal the first to fifth openings 28a to 28e. This prevents water from entering the case 24 through the first to fifth openings 28a to 28e, improving waterproofing. In particular, by providing the filler 32 over an area wider than the lower surface (mounting surface 107) of the lower case 22, for example, or over an area wider than at least the first to fifth openings 28a to 28e, water is further prevented from entering the case 24 through the first to fifth openings 28a to 28e. This further improves waterproofing.

[0094] A plurality of protrusions 116 are provided around the first and second insulating films 30a, 30b attached to the lower surface of the lower case 22. This reduces the risk that the first and second insulating films 30a, 30b will be peeled off due to the user unintentionally touching the first and second insulating films 30a, 30b. In addition, since the first and second insulating films 30a, 30b are attached to the inside of the plurality of protrusions 116, the protrusions 116 can serve as a guide when attaching the first and second insulating films 30a, 30b. Furthermore, gaps 118 are provided between the plurality of protrusions 116. Therefore, even when a filler 32 is provided on the lower surfaces of the lower case 22 and the first and second insulating films 30a, 30b, air between the lower case 22, the first and second insulating films 30a, 30b, and the filler 32 is discharged to the outside through the gaps 118. This prevents air from entering between the lower case 22, the first and second insulating films 30a, 30b, and the filler 32. As a result, heat generated in the heat-generating components (the fuse 12, and the first and second relays 14a, 14b) can be stably dissipated.

[0095] In particular, by arranging the multiple triangular protrusions 116 in a direction that gradually narrows toward the inside, it is possible to ensure a large inner opening dimension in the gap 118 between the protrusions 116, 116. This makes it possible to more efficiently capture and discharge the air pushed out by the first and second insulating films 30a, 30b and the filler 32. In addition, it is possible to keep the outer opening dimension in the gap 118 between the protrusions 116, 116 small. This can further reduce the risk of a user unintentionally touching the first and second insulating films 30a, 30b.

[0096] The lower case 22 has first to fifth positioning portions 110a to 110e for positioning the first to fifth heat dissipation bus bars 18a to 18e, and when the first to fifth heat dissipation bus bars 18a to 18e are positioned by the first to fifth positioning portions 110a to 110e, the lower surface (mounting surface 107) of the lower case 22 and the lower surfaces of the first to fifth heat dissipation portions 26a to 26e are flush with each other. This makes it possible to suppress or prevent a step from occurring between the mounting surface 107 and the lower surfaces of the first to fifth heat dissipation portions 26a to 26e, which would otherwise deteriorate the workability of attaching the first and second insulating films 30a, 30b, even when the first and second insulating films 30a, 30b are attached to seal the first to fifth openings 28a to 28e. Furthermore, the step makes it impossible to fix the first and second insulating films 30a, 30b to the lower case 22 in a flat manner, which advantageously suppresses or prevents air from being trapped between the first and second insulating films 30a, 30b and the filler 32, thereby reducing heat dissipation performance.

[0097] Particularly, in the first embodiment, the fuse connection portion 84 and the relay connection portion 88 of the first to fifth heat dissipation busbars 18a to 18e are inserted through the first to fifth insertion holes 111a to 111e provided in the lower case 22. Then, the fuse connection portion 84 and the relay connection portion 88 are aligned with the connection portion 38 and the first to fourth connection portions 44a to 44d of the fuse 12 and the first and second relays 14a and 14b. Here, first and second tolerance absorbing structures are provided to absorb the tolerances in these connection positions. Therefore, the connection portion 38 and the first to fourth connection portions 44a to 44d of the fuse 12 and the first and second relays 14a and 14b can be stably connected to the fuse connection portion 84 and the relay connection portion 88 of the first to fifth heat dissipation busbars 18a to 18e by bolt fastening.

[0098] In embodiment 1, the above-mentioned first and second tolerance absorption structures are configured by a structure that allows the bolt insertion holes 90 and nuts 99, which are elongated holes in the vertical direction, to be displaced in the vertical direction, so that a tolerance absorption structure can be realized with a simple structure.

[0099] In the first embodiment, a working hole 120 is provided penetrating the case 24 in the thickness direction. The first to fourth connection parts 44a to 44d of the first and second relays 14a, 14b, the relay connection parts 64, 68, 76 of the second to fourth current-carrying busbars 16b to 16d, and the relay connection part 88 of the second to fifth heat-dissipating busbars 18b to 18e can be bolted through the working hole 120. This improves workability without fixing the second to fourth current-carrying busbars 16b to 16d and the second to fifth heat-dissipating busbars 18b to 18e separately to the first and second relays 14a, 14b. In particular, the relay connection parts 88 of the second to fifth heat-dissipating busbars 18b to 18e have bolt insertion holes 90 constituting the first tolerance absorbing structure, thereby further improving workability.

[0100] The first to fifth positioning portions 110a-110e that position the first to fifth heat dissipation busbars 18a-18e in the case 24 (lower case 22) are formed by the top plates of the first to fifth recesses 108a-108e that accommodate the first to fifth heat dissipation portions 26a-26e of the first to fifth heat dissipation busbars 18a-18e. That is, with a simple configuration in which the first to fifth recesses 108a-108e are provided in the lower surface of the lower case 22 to accommodate the first to fifth heat dissipation portions 26a-26e, it is possible to simultaneously achieve the effect of making the mounting surface 107 in the lower case 22 flush with the lower surfaces of the first to fifth heat dissipation portions 26a-26e and the effect of positioning the first to fifth heat dissipation busbars 18a-18e.

[0101] The first insertion hole 111a, into which the second bolt 130 and a fastening tool are inserted when the connection portion (fuse connection portion 84) of the first heat dissipation busbar 18a and the connection portion 38 of the fuse 12 are bolted together, is closed by the lid portion 128. This prevents water from entering through the first insertion hole 111a and prevents the user from unintentionally touching the first heat dissipation busbar 18a. In addition, after the first insulating film 30a is attached, for example, the user's fingers or the like from entering the case 24 through the first insertion hole 111a and breaking through the first insulating film 30a is prevented. In particular, in the first embodiment, the lower surfaces of the lower case 22, the first to fifth heat dissipation portions 26a to 26e, and the lid portion 128 are flush with each other, advantageously suppressing or preventing the occurrence of steps. Therefore, the work of attaching the first and second insulating films 30a, 30b can be performed smoothly, and by flattening the contact surfaces of the first and second insulating films 30a, 30b toward the filler 32, air getting in between the first and second insulating films 30a, 30b and the filler 32, which would otherwise result in a decrease in heat dissipation, is advantageously suppressed or prevented.

[0102] <Other embodiments> The technology described in this specification is not limited to the embodiments described in the above description and drawings, and for example, the following embodiments are also included in the technical scope of the technology described in this specification.

[0103] (1) In the above embodiment, three heat-generating components (the fuse 12, and the first and second relays 14a, 14b) are provided, but it is sufficient to provide at least one heat-generating component.

[0104] (2) In the above embodiment, the current-carrying bus bars 16 (first to fourth current-carrying bus bars 16a to 16d) and the heat-dissipating bus bars (first to fifth heat-dissipating bus bars 18a to 18e) are provided separately, but the current-carrying bus bars and the heat-dissipating bus bars may be provided integrally. In other words, a heat-dissipating portion may be provided on a metal plate for current-carrying and heat-dissipating, and the heat-dissipating portion may be in thermal contact with a heat-dissipating target via an insulating film and a thermally conductive filler member.

[0105] (3) The structure of the case that houses the heat-generating component and the metal plate is not limited to the aspect described in the above embodiment. For example, the opening of the lower case may be larger than the opening of the upper case, and the side wall of the upper case may be located inside the peripheral wall of the lower case. If there is a risk of water entering between the upper case and the lower case, a conventionally known waterproof structure may be provided between the upper case and the lower case.

[0106] (4) In the above embodiment, the opening window 98 constituting the working hole 120 in the front of the case 24 was provided in the upper case 20. However, as in the circuit assembly 140 shown in FIG. 9, an opening window 142 opening upward may be provided in the peripheral wall 102 of the lower case 144. The upper opening of the opening window 142 may be blocked by the side wall 94 of the upper case 146 to form the working hole 120. Note that in the above embodiment and the aspect shown in FIG. 9, the lower opening and the upper opening of the opening window 98, 142 opening downward and upward are blocked by the peripheral wall 102 of the lower case 22 and the side wall 94 of the upper case 146 to form the working hole 120, but the present invention is not limited to these aspects. A working hole penetrating in the thickness direction may be directly formed in the side wall of the upper case or the peripheral wall of the lower case, or an opening window may be provided in both the side wall of the upper case and the peripheral wall of the lower case, and these opening windows may be overlapped in the front-rear direction to form the working hole. In the embodiment shown in Fig. 9, a mounting portion 48 is provided at the lower part of the relay body 42 of the first relay 14a, and the first relay 14a is fixed to the lower case 144 by a second bolt 130 inserted into a bolt insertion hole 50 of the mounting portion 48. In this manner, the heat-generating components and metal plates housed inside the case may be assembled to the lower case.

[0107] (5) In the above embodiment, the lower case 22 has the mounting surface 107, and the openings 28 (the first to fifth openings 28a to 28e) are formed on the mounting surface 107. However, the present disclosure is not limited to this. For example, the circuit configuration may have a case structured such that the side wall of the upper case is provided with a fixing portion for a heat dissipation target and the case is fixed to the heat dissipation target by the fixing portion, without providing a lower case. In this case, an insulating film that is larger than the heat dissipation portion over the entire circumference is fixed to the lower surface of the heat dissipation portion, and a heat-conductive filling member is disposed between the insulating film and the housing. This not only ensures electrical insulation between the heat dissipation portion and the housing, but also exhibits good heat conductivity, and the effects of the present disclosure can be enjoyed in the same way. In particular, by fixing the insulating film to the end face of the side wall of the upper case to seal the opening of the case, water is prevented from entering the case.

[0108] (6) In the above embodiment, the working holes 120 were closed by the caps 122, but if the working holes are provided at a position equal to or higher than the height of water expected to form on the housing due to condensation or the like, a cap for closing the working holes may not be provided. Also, in the above embodiment, four working holes 120 are provided, and two caps 122 are provided to close two adjacent working holes 120, but four caps may be provided to separately close each working hole, or one cap may be provided to close the four working holes.

[0109] (7) In the above embodiment, a plurality of triangular protrusions 116 are provided around the first and second insulating films 30a, 30b on the lower surface (mounting surface 107) of the lower case 22, but the present invention is not limited to this. The protrusions may be polygonal, such as a square, or may be circular (including a perfect circle, an ellipse, an oval, a semicircle, etc.). Even if the protrusions are triangular, they do not need to be narrowed from the outside to the inside as in the above embodiment, and may be narrowed from the inside to the outside. Alternatively, the protrusions may be provided in an area covering, for example, 1 / 3 or 1 / 2 of the circumference of the insulating film, or protrusions may be provided around approximately the entire circumference, with a notched gap provided in a part of the circumference. This allows air to escape between the lower case and the insulating film and the filler through the gap when the insulating film is attached. However, the gap between the protrusions is not essential, and the protrusions may be provided continuously around the entire circumference of the insulating film. In such a case, the effect of preventing the insulating film from peeling off can be more stably obtained. Note that in the present disclosure, the protrusion provided on the lower surface of the lower case is not essential.

[0110] (8) In the above embodiment, the filler 32 is grease-like when applied and becomes sheet-like after curing, but this is not limited thereto, and for example, a conventionally known heat conductive sheet or the like may be used. Also, in the above embodiment, the filler 32 is provided over an area wider than the lower surface of the lower case 22, but the arrangement area is not limited thereto. The filler may be provided over an area narrower than the lower surface of the lower case, or may be provided in an arrangement area smaller than the insulating film in a plan view.

[0111] (9) In the above embodiment, the first and second insulating films 30a, 30b are larger than the first to fifth openings 28a-28e in a plan view, and the first to fifth openings 28a-28e are sealed by the first and second insulating films 30a, 30b. However, the insulating films may be smaller than the openings of the case in a plan view. In this case, a waterproofing mechanism may be separately adopted to prevent water from entering the case.

[0112] (10) In the above embodiment, the second insulating film 30b is a single film large enough to cover the second to fifth openings 28b to 28e, but the second to fifth openings may be sealed by separate insulating films. In the above embodiment, two insulating films are provided, the first insulating film 30a sealing the first opening 28a and the second insulating film 30b sealing the second to fifth openings 28b to 28e, but a single insulating film covering the first to fifth openings may be provided. In the above embodiment, the first and second insulating films 30a and 30b are each rectangular, but the shape is not limited thereto. [Explanation of symbols]

[0113] 10 Circuit structure 12 Fuse (heat generating component, second heat generating component) 14 Relay (heat generating component, first heat generating component) 14a 1st Relay 14b 2nd Relay 16 Current carrying busbar 16a First current busbar 16b Second current bus bar 16c 3rd current busbar 16d 4th current busbar 18 Heat dissipation busbar (metal plate) 18a First heat dissipation busbar (metal plate for second heat generating component) 18b Second heat dissipation bus bar (metal plate for first heat generating component) 18c 3rd heat dissipation busbar (metal plate for 1st heat generating component) 18d 4th heat dissipation busbar (metal plate for 1st heat generating component) 18e 5th heat dissipation busbar (metal plate for 1st heat generating component) 20 Upper Case 22 Lower case 24 cases 26 Heat radiation part 26a 1st heat dissipation section 26b 2nd heat dissipation section 26c 3rd heat dissipation section 26d 4th heat dissipation section 26e 5th heat dissipation section 28 Opening 28a 1st opening 28b 2nd opening 28c 3rd opening 28d 4th opening 28e 5th opening 29 Chassis (heat dissipation target) 30 Insulating film 30a First insulating film 30b Second insulating film 32 Filler (thermally conductive filling material) 34 Contact surface 36 Fuse body 38 Connection 40 Bolt insertion hole 42 Relay body 44 Connection 44a First connection part 44b Second connection part 44c Third connection part 44d 4th connection part 46 Partition 48 Mounting part 50 Bolt hole 52 External connection part 54 Fuse connection 56,58 Bolt holes 60 Fuse connection 62 Bolt insertion hole 64 Relay connection 66 Bolt insertion hole 68 Relay connection 70 Bolt insertion hole 72 External connection part 74 Bolt insertion hole 76 Relay connection 78 Bolt insertion hole 80 External connection part 82 Bolt insertion hole 84 Fuse connection part (connection part) 84a 1st area 86 Bolt insertion hole 87 Connecting part 87a 2nd area 88 Relay connection part (connection part) 90 Bolt insertion hole (first tolerance absorption structure) 92 Ceiling wall 94 Side wall 96,98 Opening window 99 Nut 100 Bottom wall 102 Peripheral wall 104 Support part 106 Nut 107 Placement surface 108 Recess 108a First recess 108b Second recess 108c Third recess 108d 4th recess 108e 5th recess 110 Positioning part 110a: First positioning portion (second metal plate positioning portion) 110b Second positioning portion (first metal plate positioning portion) 110c: third positioning portion (first metal plate positioning portion) 110d Fourth positioning portion (first metal plate positioning portion) 110e Fifth positioning portion (first metal plate positioning portion) 111 Insertion hole 111a First insertion hole 111b Second insertion hole 111c 3rd insertion hole 111d 4th insertion hole 111e 5th insertion hole 112 Lid housing 114 Bottom part 116 Protrusion 118 Gap 120 Working hole 122 Cap 124 Base plate part 126 Claw 128 Lid 130 Second Bolt 132 First Bolt 140 Circuit constructs 142 Opening window 144 Lower Case 146 Upper Case S Gap

Claims

1. A heat generating component that generates heat when electricity is applied; a case for accommodating the heat generating component; and a metal plate formed separately from the case and housed within the case, the metal plate being connected to a connection portion of the heat-generating component and having a heat dissipation portion exposed to the outside of the case and in thermal contact with an external heat dissipation target; an insulating film for covering a contact surface of the heat dissipation portion with the heat dissipation target; a thermally conductive filler member that is in thermal contact with the heat dissipation portion via the insulating film and is disposed between the insulating film and the heat dissipation target; Including, the case has an opening, the heat dissipation portion is inserted through the opening and exposed to the outside of the case, and the insulating film is fixed to the case around the entire periphery of the opening, thereby sealing the opening with the insulating film; The case has a plurality of protrusions arranged around a peripheral edge of the insulating film with gaps between them. circuit construct.

2. The circuit assembly according to claim 1 , wherein the insulating film and the thermally conductive filler are disposed in different areas.

3. The case includes an upper case and a lower case, 3. The circuit structure according to claim 1, wherein the plurality of protrusions are each triangular when projected in the assembly direction of the upper case and the lower case, and are arranged so that their width gradually narrows toward the insulating film located on the inside.

4. The case includes an upper case and a lower case, the heat generating component is fixed to at least one of the upper case and the lower case, the lower case has a mounting surface for mounting the heat dissipation target, and the opening is provided on the mounting surface, the lower case has a positioning portion that positions the heat dissipation portion of the metal plate arranged in the opening so as to be flush with the mounting surface, the metal plate is provided with a connection portion to the connection portion of the heat generating component, 4. The circuit assembly according to claim 1, further comprising a tolerance absorbing structure that absorbs a tolerance between the connection site and the connection portion when the heat dissipation portion is positioned by the positioning portion.

5. The heat generating component includes a first heat generating component, the metal plate includes a first heat generating component metal plate connected to the connection portion of the first heat generating component, 5. The circuit assembly according to claim 4, wherein the connection portion of the first heat-generating component and the connection portion of the metal plate for the first heat-generating component are fastened using a first bolt extending in a direction perpendicular to an assembly direction of the upper case and the lower case, a bolt insertion hole having an elongated hole shape extending in the assembly direction of the upper case and the lower case is provided in the fastening portion of the metal plate for the first heat-generating component, the bolt insertion hole forms a first tolerance absorption structure, and the tolerance absorption structure includes the first tolerance absorption structure.

6. 6. The circuit structure according to claim 5, wherein the upper case has a top wall and a side wall protruding from the top wall toward the lower case, the lower case has a bottom wall and a peripheral wall protruding from the bottom wall toward the upper case, and at least one of the side wall and the peripheral wall is provided with a working hole through which the first bolt and a tool for fastening the first bolt can be inserted.

7. A heat generating component that generates heat when current is applied; a case for accommodating the heat generating component; and a metal plate having a heat dissipation portion connected to a connection portion of the heat generating component and exposed to the outside of the case to be in thermal contact with an external heat dissipation target; an insulating film for covering a contact surface of the heat dissipation portion with the heat dissipation target; a thermally conductive filler member that is in thermal contact with the heat dissipation portion via the insulating film and is disposed between the insulating film and the heat dissipation target; Including, The case includes an upper case and a lower case, the heat generating component is fixed to at least one of the upper case and the lower case, the lower case has a mounting surface for mounting the heat dissipation target, and an opening is provided in the mounting surface, the lower case has a positioning portion that positions the heat dissipation portion of the metal plate arranged in the opening so as to be flush with the mounting surface, the metal plate is provided with a connection portion to the connection portion of the heat generating component, a tolerance absorbing structure is provided that absorbs a tolerance between the connection site and the connection portion when the heat dissipation portion is positioned by the positioning portion, The heat generating component includes a first heat generating component, the metal plate includes a first heat generating component metal plate connected to the connection portion of the first heat generating component, the connection portion of the first heat-generating component and the connection portion of the metal plate for the first heat-generating component are fastened using a first bolt extending in a direction perpendicular to an assembly direction of the upper case and the lower case, a bolt insertion hole having an elongated hole shape extending in the assembly direction of the upper case and the lower case is provided in the fastening portion of the metal plate for the first heat-generating component, the bolt insertion hole constitutes a first tolerance absorbing structure, and the tolerance absorbing structure includes the first tolerance absorbing structure, the first metal plate for heat generating components is bent into an L-shape, one end of the first metal plate for heat generating components is the heat dissipation portion extending parallel to the mounting surface of the lower case, and the other end of the first metal plate for heat generating components is the connection portion rising toward the upper case, a circuit structure in which the mounting surface of the lower case is provided with a slit-shaped insertion hole that allows the connection portion to be inserted, and a recess that is connected to the insertion hole and recessed toward the upper case to accommodate the heat dissipation portion, the opening is formed including the insertion hole and the recess, and a first metal plate positioning portion that positions the metal plate for the first heat-generating component is formed by a top plate of the recess, and the positioning portion includes the first metal plate positioning portion.

8. A heat generating component that generates heat when current is applied; a case for accommodating the heat generating component; and a metal plate having a heat dissipation portion connected to a connection portion of the heat generating component and exposed to the outside of the case to be in thermal contact with an external heat dissipation target; an insulating film for covering a contact surface of the heat dissipation portion with the heat dissipation target; a thermally conductive filler member that is in thermal contact with the heat dissipation portion via the insulating film and is disposed between the insulating film and the heat dissipation target; Including, The case includes an upper case and a lower case, the heat generating component is fixed to at least one of the upper case and the lower case, the lower case has a mounting surface for mounting the heat dissipation target, and an opening is provided in the mounting surface, the lower case has a positioning portion that positions the heat dissipation portion of the metal plate arranged in the opening so as to be flush with the mounting surface, the metal plate is provided with a connection portion to the connection portion of the heat generating component, a tolerance absorbing structure is provided that absorbs a tolerance between the connection site and the connection portion when the heat dissipation portion is positioned by the positioning portion, The heat generating component includes a second heat generating component, the metal plate includes a second heat generating component metal plate connected to the connection portion of the second heat generating component, the second heat-generating component metal plate has the heat dissipation portion provided on one end side and extending parallel to the mounting surface of the lower case, the connection portion provided on the other end side and positioned closer to the upper case than the heat dissipation portion and extending parallel to the heat dissipation portion, and a coupling portion rising from the heat dissipation portion toward the connection portion, the mounting surface of the lower case is provided with an insertion hole that allows the connection portion and the coupling portion to pass through, and a recess that is connected to the insertion hole and recessed toward the upper case to accommodate the heat dissipation portion, the opening is formed by including the insertion hole and the recess, a second metal plate positioning portion that positions the second heat generating component metal plate is formed by a top plate of the recess, and the positioning portion includes the second metal plate positioning portion, a circuit structure, wherein the connection portion is fastened to the connection portion of the second heat-generating component by a second bolt, and a nut to which the second bolt housed in the upper case is fastened is held so as to be displaceable in a direction away from the mounting surface of the lower case, thereby forming a second tolerance absorbing structure, and the tolerance absorbing structure includes the second tolerance absorbing structure.

9. 9. The circuit structure described in claim 8, wherein the insertion hole has a first region through which the connection portion is permitted to pass and a second region through which the connecting portion is permitted to pass, and a lid portion covering the first region of the insertion hole is removably fixed to the mounting surface.

Images