Circuit structure

Abstract

Disclosed is a circuit structure capable of reducing stress generated at an interface between a heat conduction member and a housing. A circuit structure (10) is provided with: heat-generating components (12, 14); a bus bar (18) connected to the connection portion (16) of the heat generating components (12, 14); a housing (20) that accommodates the heat generating components (12, 14) and the bus bar (18); and a heat conduction member (24) which is placed on the surface (22) on which the housing (20) is placed, is in thermal contact with the housing (20) and the bus bar (18), and is sandwiched between the housing (20) and the bus bar (18), the housing (20) having a displacement restricting part (118) which engages with the heat conduction member (24) and restricts the displacement of the heat conduction member (24).

Description

Technical Field

[0001] The present disclosure relates to a circuit structure including a heat generating component. Background Art

[0002] In the past, a circuit structure including a heat generating component such as a relay was installed in a vehicle. For example, Patent Document 1 discloses a circuit structure in which a first bus bar connected to an output terminal of a battery, a second bus bar connected to an input terminal of a load, and a relay connected between the first bus bar and the second bus bar are accommodated in a housing. In such a circuit structure, in order to dissipate the heat generated by the relay as a heat generating component to the outside, the following structure is adopted: the bus bar connected to the relay is pressed to the housing via a sheet-like heat conducting member, and the heat of the relay is transferred to the housing.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-93711 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in the structure of Patent Document 1, the heat conduction member disposed in the predetermined arrangement area of ​​the housing via an adhesive or the like is merely held in the predetermined arrangement area by being sandwiched between one housing (device cover) and the other housing (battery housing). Therefore, when an excessive impact or the like is applied, or when relative displacement between the housings occurs due to a difference in linear expansion coefficients between one housing and the other housing, strain is generated at the interface between the heat conduction member and the housing, and a gap may be generated therebetween, thereby reducing heat transfer efficiency.

[0008] Therefore, a circuit structure is disclosed that can reduce the stress generated at the interface between a heat conducting member and a housing.

[0009] Means for solving problems

[0010] The circuit structure disclosed in the present invention comprises: a heat-generating component; a bus bar connected to a connection portion of the heat-generating component; a housing accommodating the heat-generating component and the bus bar; and a heat-conducting member placed on a placement surface of the housing, in thermal contact with the housing and the bus bar and clamped therebetween, the housing having a displacement limiting portion that engages with the heat-conducting member to limit displacement of the heat-conducting member.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to provide a circuit structure capable of reducing stress generated at the interface between a heat conduction member and a housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a perspective view showing the circuit structure according to the first embodiment.

[0014] Figure 2 yes Figure 1 A top view of the circuit structure shown.

[0015] Figure 3 Yes Figure 2 The longitudinal sectional view is an enlarged view of the III-III section.

[0016] Figure 4 yes Figure 1 An exploded perspective view of the circuit structure shown.

[0017] Figure 5 It is composed Figure 1 The diagram is a perspective view of an upper case of a circuit structure as viewed from the bottom side.

[0018] Figure 6 It is composed Figure 1 A perspective view of the lower housing of the circuit structure shown.

[0019] Figure 7 is a longitudinal sectional view showing a circuit structure according to Embodiment 2, Figure 3 The corresponding figure.

[0020] Figure 8 It is composed Figure 7 The diagram is a perspective view of an upper case of a circuit structure as viewed from the bottom side.

[0021] Fig. 9 It is composed Figure 7 A perspective view of the lower housing of the circuit structure shown.

[0022] Fig.10 is a longitudinal sectional view showing a circuit structure involved in Embodiment 3, which is equivalent to Figure 2 The cross section along the XX section line in the figure is shown.

[0023] Fig.11 It is composed Fig.10 The diagram is a perspective view of an upper case of a circuit structure as viewed from the bottom side.

[0024] Fig.12 It is composed Fig.10 A perspective view of the lower housing of the circuit structure shown. DETAILED DESCRIPTION

[0025] <Description of Embodiments of the Present Disclosure>

[0026] First, embodiments of the present disclosure are listed and described.

[0027] The circuit structure disclosed in the present invention comprises: a heat-generating component; a bus bar connected to a connection portion of the heat-generating component; a housing accommodating the heat-generating component and the bus bar; and a heat-conducting member placed on a placement surface of the housing, in thermal contact with the housing and the bus bar and clamped therebetween, the housing having a displacement limiting portion that engages with the heat-conducting member to limit displacement of the heat-conducting member.

[0028] According to the circuit structure disclosed in the present invention, the housing that accommodates the heat-generating component and the bus bar connected to the connection portion of the heat-generating component has a displacement limiting portion that engages with the heat-conducting member that is in thermal contact with the housing and the bus bar and is clamped therebetween. The displacement limiting portion can engage with the heat-conducting member to limit the displacement of the heat-conducting member. Therefore, the displacement of the heat-conducting member relative to the housing is advantageously suppressed or prevented, and the stress generated at the interface between the housing and the heat-conducting member can be advantageously reduced or eliminated. As a result, the possibility of a gap being generated at the interface between the housing and the heat-conducting member can be reduced, and the desired heat conduction performance of the circuit structure that is transmitted from the connection portion of the heat-generating component to the housing via the bus bar and the heat-conducting member can be stably maintained. It should be noted that the displacement of the heat-conducting member relative to the housing only needs to be suppressed or prevented in at least one of the front-to-back direction, the left-to-right direction, and the up-down direction in the embodiments described later.

[0029] In addition, the bus bar connected to the connection portion of the heat generating component may constitute a through-circuit, or may be used as a simple heat dissipation metal without being electrically connected to other members.

[0030] Preferably, the displacement limiting portion has a protrusion protruding from the mounted surface of the housing, the heat conduction member has a through hole through which the protrusion is inserted, and the bus bar has a through hole through which the protrusion overlaps with the through hole. Since the protrusion protruding from the mounted surface of the housing is inserted into the through hole of the heat conduction member, the stress generated at the interface between the housing and the heat conduction member can be advantageously reduced. Moreover, since the same protrusion is also inserted into the through hole provided in the bus bar overlapping with the heat conduction member, even in the case where the heat conduction member and the bus bar are respectively held in one housing and the other housing having different linear expansion coefficients, the transmission of the displacement force applied to the heat conduction member via the bus bar can be suppressed, and the stress generated at the interface between the housing and the heat conduction member can be advantageously reduced.

[0031] Preferably, the housing includes a lower housing having the placement surface and an upper housing assembled with the lower housing by sandwiching the heat conduction member and the bus bar, the upper housing includes a locked portion, and the protrusion includes a locking portion provided on the lower housing and locked and fitted to the locked portion. Since the housing includes a lower housing having the placement surface and an upper housing assembled with the lower housing by sandwiching the heat conduction member and the bus bar, the protrusion is formed by the locking portion that realizes the locking and fitting of the lower housing and the upper housing, so that the protrusion can be efficiently provided. Moreover, since the locking portion constituting the protrusion is provided on the placement surface on which the heat conduction member is placed, the fitting force of the lower housing and the upper housing can be directly applied to the overlapping portion of the heat conduction member and the bus bar, and the displacement of the heat conduction member relative to the housing can be further advantageously suppressed. As a result, even in the case where the linear expansion coefficients of the lower housing and the upper housing are different, the relative displacement of the two housings near the heat conduction member can be further advantageously suppressed, and the stress generated at the interface between the housing and the heat conduction member can be advantageously reduced.

[0032] It should be noted that by adjusting the locking margin between the locking portion and the locked portion, the pressing force of the heat conduction member against the housing caused by the locking engagement of the upper housing and the lower housing can be adjusted. Therefore, by appropriately adjusting the locking margin, the pressing force can be adjusted according to the material, elastic properties, etc. of the heat conduction member.

[0033] Preferably, the upper housing has a positioning rib for positioning the bus bar, the bus bar is positioned by engaging with the positioning rib, and the locked portion of the upper housing is positioned at the through hole of the bus bar, the through hole of the heat conduction member, and the locking portion inserted and arranged at the through hole and the through hole. By providing the positioning rib for the bus bar on the upper housing, the locked portion of the upper housing can be positioned at the through hole of the bus bar, the through hole of the heat conduction member, and the locking portion of the lower housing inserted and arranged therein, and the assembly workability can be improved.

[0034] Preferably, the lower shell and the upper shell respectively have a guide portion and a guided portion arranged on the outer peripheral side of the locking portion and the locked portion, and when the upper shell is assembled to the lower shell, the locked portion of the upper shell is positioned at the locking portion of the lower shell by being pre-guided by the guided portion. With respect to the lower shell and the upper shell, since the locking portion and the locked portion are pre-guided by the guide portion and the guided portion on the outer peripheral side of the locking portion and the locked portion, the locking portion and the locked portion are positioned, so that the assembly workability of the lower shell and the upper shell can be further improved.

[0035] Preferably, the housing includes a lower housing having the placement surface and an upper housing assembled with the lower housing by sandwiching the heat conduction member and the bus bar, the upper housing includes a press-fit hole, and the protrusion includes a press-fit protrusion provided on the lower housing and pressed into the press-fit hole. Since the housing includes a lower housing having the placement surface and an upper housing assembled with the lower housing by sandwiching the heat conduction member and the bus bar, the protrusion is formed by the press-fit protrusion that realizes the assembly of the lower housing and the upper housing by press-fitting, so the protrusion can be efficiently provided. Moreover, since the press-fit protrusion that constitutes the protrusion is provided on the placement surface on which the heat conduction member is placed, the assembly force of the lower housing and the upper housing can be directly applied to the overlapping portion of the heat conduction member and the bus bar, and the displacement of the heat conduction member relative to the housing can be further advantageously suppressed.

[0036] Preferably, the displacement limiting portion has an elastic locking piece protruding from the periphery of the mounted surface of the housing, the elastic locking piece having a flexing piece that can be elastically deformed toward the outer peripheral side of the heat conduction member and a locking claw portion provided at the protruding end of the flexing piece, the locking claw portion being engaged with the edge of the busbar overlapping the heat conduction member. By providing an elastic locking piece protruding from the periphery of the mounted surface and engaging the locking claw of the elastic locking piece with the edge of the busbar overlapping the heat conduction member, the displacement of the heat conduction member relative to the housing can be suppressed. As a result, the displacement of the heat conduction member relative to the mounted surface can be further advantageously suppressed and the stress generated at the interface between the heat conduction member and the housing can be further advantageously sought to be reduced. In addition, since there is no need to provide a hole in the busbar, the conduction resistance of the busbar can be advantageously maintained when the busbar is used as a conducting member.

[0037] Preferably, the upper housing has a pressing portion for bringing the bus bar into contact with the heat conduction member, and the locked portion is provided on the pressing portion. The upper housing is provided with a pressing portion for bringing the bus bar into contact with the heat conduction member, and the locked portion is provided on the pressing portion. Thus, the bus bar can be pressed against the heat conduction member by utilizing the fastening force based on the locking structure of the upper housing and the lower housing, which can help maintain the heat conduction efficiency and prevent the heat conduction member from displacement relative to the housing at the same time.

[0038] <Details of Embodiments of the Present Disclosure>

[0039] Below, while referring to the attached Figure 1 It should be noted that the present disclosure is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0040] <Implementation Method 1>

[0041] Below, while referring to Figure 1 to Figure 6 Embodiment 1 of the present disclosure will be described. The circuit structure 10 of Embodiment 1 is mounted on a vehicle (not shown) such as an electric vehicle or a hybrid vehicle, and supplies and controls power from a power source (not shown) such as a battery to a load (not shown) such as an electric motor. The circuit structure 10 can be arranged in any orientation, but in the following, the upper side is set as Figure 3 In the upper part, set the lower part to Figure 3 , set the front Figure 2 , set the back to Figure 2 In the top, set the left Figure 2 The left side of the Figure 2 In addition, regarding a plurality of identical components, sometimes only a part of the components are denoted by reference numerals, and reference numerals are omitted for the other components.

[0042] <Circuit Structure 10>

[0043] The circuit structure 10 includes a relay 12 and a fuse 14 as heat-generating components that generate heat when energized, a bus bar 18 connected to a connection portion 16 of the heat-generating components (the relay 12 and the fuse 14), a housing 20 that accommodates the heat-generating components (the relay 12 and the fuse 14) and the bus bar 18, and a heat-conducting sheet 24 (a first to a third heat-conducting sheet 24c described below) as a heat-conducting member that is placed on a placement surface 22 (a first to a third placement surface 22a to 22c described below) of the housing 20 and is in thermal contact with the housing 20 and the bus bar 18 and is sandwiched therebetween.

[0044] <Heat generating components (relay 12 and fuse 14)>

[0045] The relay 12 includes a relay body 26 formed in a hollow rectangular parallelepiped shape. On the front surface of the relay body 26, a pair of connection parts 16, 16 (a first connection part 16a and a second connection part 16b) are provided in a mutually separated manner in the left-right direction. An insulating plate 28 protruding forward is provided between these first connection parts 16a and the second connection parts 16b. In addition, a plurality of legs 30 protruding outward in the left-right direction are provided on the relay body 26. In the first embodiment, bolt insertion holes penetrating in the up-down direction are formed in these legs 30, and the relay 12 is fixed to the upper housing 58 described later constituting the housing 20 by bolts inserted into these bolt insertion holes.

[0046] The fuse 14 includes a fuse body 32 formed in a substantially rectangular parallelepiped shape. The fuse body 32 is provided with metal connection parts 16, 16 (third connection part 16c and fourth connection part 16d) protruding to both sides in the left and right directions. Bolt insertion holes 34 penetrating in the up-down direction are formed in these third and fourth connection parts 16c, 16d, and the fuse 14 is fixed to the upper housing 58 described later constituting the housing 20 by bolts 36 inserted into these bolt insertion holes 34.

[0047] <Bus bar 18>

[0048] The bus bar 18 is formed by bending a metal plate into a predetermined shape by press working or the like. The material of the bus bar 18 is not limited, but copper, copper alloy, aluminum, aluminum alloy, etc. are preferably used. Figure 4 As shown, in the first embodiment, three bus bars 18 are provided in a mutually separated manner in the left-right direction, and are the first bus bar 18a, the second bus bar 18b, and the third bus bar 18c in order from the left. Figure 5 , 6 In the figure, the first to third bus bars 18a, 18b, and 18c in a state of being fixed to an upper case 58 and a lower case 60 described later are respectively indicated by two-dot chain lines.

[0049] The first bus bar 18a extends in the left-right direction as a whole. The first bus bar 18a has a roughly rectangular relay connection portion 38 (first relay connection portion 38a) extending in the up-down direction at the right end. A roughly rectangular heat transfer portion 40 (first heat transfer portion 40a) extending in the horizontal direction (a direction orthogonal to the up-down direction) extends rearward from the lower end of the first relay connection portion 38a. In addition, the first bus bar 18a has a roughly rectangular left external connection portion 42 extending in the horizontal direction at the left end. The left external connection portion 42 is located above the first heat transfer portion 40a, and the left external connection portion 42 and the first heat transfer portion 40a are connected by a portion bent into a crank shape at the middle portion in the left-right direction.

[0050] A bolt insertion hole 44 is formed in the first relay connection portion 38a and penetrates in the thickness direction (front-back direction). In Embodiment 1, the bolt insertion hole 44 is formed in an oblong shape that is long in the up-down direction. Thus, when the relay 12 and the first bus bar 18a described later are fastened by bolts, the up-down position of the first bus bar 18a relative to the relay 12 can be adjusted. As a result, when the circuit structure 10 is assembled, the first heat transfer portion 40a can be made to be in more reliable thermal contact with the lower housing 60 described later via the heat conduction sheet 24 (first heat conduction sheet 24a). In addition, a bolt insertion hole 46 is formed in the left external connection portion 42 and penetrates in the thickness direction (up-down direction).

[0051] The second bus bar 18b extends in the left-right direction as a whole. A substantially rectangular relay connection portion 38 (second relay connection portion 38b) extending in the up-down direction is provided at the left end of the second bus bar 18b, and a bolt insertion hole 44 formed in an oblong shape long in the up-down direction is formed in the second relay connection portion 38b. A substantially rectangular heat transfer portion 40 (second heat transfer portion 40b) extending in the horizontal direction is connected to the lower end of the second relay connection portion 38b. The second heat transfer portion 40b extends rearward from the lower end of the second relay connection portion 38b, and extends in the left-right direction from the second relay connection portion 38b at the left end of the second bus bar 18b to the right portion of the second bus bar 18b. In addition, the second bus bar 18b has a substantially rectangular fuse connection portion 48 extending in the horizontal direction at the right end. The fuse connection portion 48 is located above the second heat transfer portion 40 b , and the fuse connection portion 48 and the second heat transfer portion 40 b are connected by a portion extending in the up-down direction.

[0052] In Embodiment 1, a circular through hole 50 penetrating in the thickness direction (vertical direction) is provided substantially at the center of the second heat transfer portion 40b extending in the horizontal direction. In particular, in Embodiment 1, a pair of through holes 50, 50 are provided, and the pair of through holes 50, 50 are separated from each other in the horizontal direction. Figure 3 As shown, the inner diameter of each through hole 50 is approximately equal to or slightly smaller than the maximum outer diameter of the forming portion of each engaging claw 106 arranged at the upper end portion of each protrusion 100 of the lower shell 60 described later, and is approximately equal to or slightly larger than the outer diameter of the portion of each protrusion 100 where the engaging claw 106 is not formed.

[0053] Thus, as described later, when each protrusion 100 is inserted into each through hole 50, each engaging claw 106 (each elastic piece 104) is elastically deformed radially inward, and each protrusion 100 can be inserted into each through hole 50. In addition, after each protrusion 100 is inserted into each through hole 50, each engaging claw 106 (each elastic piece 104) elastically restores the deformation, and thus each protrusion 100 can be prevented from coming out of each through hole 50. In addition, a bolt insertion hole 52 that penetrates in the thickness direction (up and down direction) is formed in the fuse connection portion 48. That is, in the second bus bar 18b, each through hole 50 is provided close to each bolt insertion hole 44, 52.

[0054] The third bus bar 18c extends in the left-right direction as a whole. A substantially rectangular fuse connection portion 48 extending in the horizontal direction is provided at the left end of the third bus bar 18c, and a bolt insertion hole 52 penetrating in the thickness direction (vertical direction) is formed in the fuse connection portion 48. In addition, a substantially rectangular right external connection portion 54 extending in the horizontal direction is provided at the right end of the third bus bar 18c, and a bolt insertion hole 56 penetrating in the thickness direction (vertical direction) is formed in the right external connection portion 54.

[0055] In the third bus bar 18c, a substantially rectangular heat transfer portion 40 (third heat transfer portion 40c) is provided in the middle portion in the left-right direction. That is, the fuse connection portion 48 located at the left end of the third bus bar 18c and the right external connection portion 54 located at the right end are connected via the third heat transfer portion 40c. The third heat transfer portion 40c is located below the fuse connection portion 48 and the right external connection portion 54, and the third heat transfer portion 40c, the fuse connection portion 48, and the right external connection portion 54 are connected by portions extending in the up-down direction, respectively.

[0056] <Casing 20>

[0057] The housing 20 is box-shaped as a whole and is formed of, for example, synthetic resin. Figure 2 As shown, in the first embodiment, the housing 20 is formed into a substantially rectangular shape extending in the left-right direction in a plan view. The housing 20 is composed of an upper housing 58 located at the top and a lower housing 60 located at the bottom, and these upper housing 58 and lower housing 60 can be assembled and divided in the vertical direction. It should be noted that the material of the synthetic resin constituting the upper housing 58 and the lower housing 60 is not limited, but may contain fillers such as glass fiber. The material of the upper housing 58 and the material of the lower housing 60 may also be different. In particular, the material of the lower housing 60 preferably exhibits good thermal conductivity, and a nylon-based synthetic resin, such as polyimide 6 (PA6), may be used.

[0058] <Upper housing 58>

[0059] The upper housing 58 is generally box-shaped and open downward, and includes an upper bottom wall 62 that is generally rectangular and extends in the left-right direction, and an upper peripheral wall 64 that protrudes downward from the outer peripheral edge of the upper bottom wall 62. In addition, generally rectangular openings 66a and 66b that penetrate in the upper-lower direction are formed at both ends of the upper bottom wall 62 in the left-right direction. Moreover, in the front part of the upper peripheral wall 64, a notch 68 that penetrates in the thickness direction (front-back direction) is provided at a position corresponding to each connection portion 16 (first and second connection portions 16a and 16b) of the relay 12 fixed to the upper housing 58, and a pair of notches 68 and 68 are separated from each other in the left-right direction. By providing these notches 68, the bolts 120 described later can be tightened from the front to each connection portion 16 (first and second connection portions 16a and 16b) of the relay 12 fixed to the upper housing 58 through the notches 68.

[0060] And, also Figure 3 , Figure 5 As shown in the figure, a pressing portion 70 for bringing the bus bar 18 into contact with the heat conducting sheet 24 is provided on the upper housing 58. The pressing portion 70 is generally in a rectangular parallelepiped shape, and is provided to protrude downward from the upper bottom wall 62 in the internal space of the upper housing 58. In the first embodiment, the pressing portion 70 is formed integrally with the upper bottom wall 62 at a predetermined front-to-back dimension and a left-to-right dimension in the middle portion in the left-right direction of the upper bottom wall 62. In particular, in the first embodiment, the pressing portion 70 is formed with a front-to-back dimension slightly larger than the front-to-back dimension of the portion where each through hole 50 is formed in the second heat transfer portion 40b of the second bus bar 18b.

[0061] In addition, the pressing portion 70 has a predetermined vertical dimension, and as described later, the pressing portion 70 overlaps with a bottom wall 90 (described later) of the lower case 60 via the bus bar 18 (second bus bar 18b) and the heat conducting sheet 24 (second heat conducting sheet 24b) in a state where the bus bar 18 (second bus bar 18b) and the heat conducting sheet 24 (second heat conducting sheet 24b) are overlapped with the lower end of the pressing portion 70. In other words, the upper case 58 and the lower case 60 are assembled to each other in a state where the heat conducting sheet 24 (second heat conducting sheet 24b) and the bus bar 18 (second bus bar 18b) are sandwiched between the pressing portion 70 and the bottom wall 90 in the vertical direction.

[0062] The pressing portion 70 has a plurality of substantially rectangular weight-reducing holes 72 opening downward, and these plurality of weight-reducing holes 72 are arranged in the front-to-back direction and the left-to-right direction. Thus, when viewed from above from the upper shell 58, the pressing portion 70 is formed in a substantially lattice shape. In addition, a locked portion 74 is formed in the pressing portion 70 for locking and engaging with a locking portion 102 to be described later provided on the lower shell 60. Specifically, the locked portion 74 is provided at the lower end portion of a cylindrical portion 76 protruding downward from the upper bottom wall 62. In embodiment 1, the cylindrical portion 76 is provided in the weight-reducing hole 72 in the central portion of the pressing portion 70 in the front-to-back direction, and a pair of cylindrical portions 76, 76 are provided separately from each other in the left-to-right direction. That is, in the upper shell 58, a pair of locked portions 74, 74 are provided separately from each other in the left-to-right direction.

[0063] In more detail, at the lower end portion of each cylindrical portion 76, engaged claws 78 protruding toward the inner circumference are provided on both sides in the front-rear direction, thereby constituting the locked portion 74 of the lower end portion of each cylindrical portion 76. In addition, the lower end surfaces of each engaged claw 78 facing each other in the front-rear direction are respectively formed as inclined surfaces 80, and each of these inclined surfaces 80 is inclined in a direction in which the distance between the facing surfaces in the front-rear direction gradually increases as it goes downward.

[0064] In addition, positioning ribs 82 for positioning the bus bar 18 (second bus bar 18b) are provided at both ends of the pressing portion 70 in the front-to-back direction. These positioning ribs 82 are provided to protrude downward from both ends of the pressing portion 70 in the front-to-back direction. In Embodiment 1, positioning ribs 82, 82 having a predetermined left-to-right dimension are provided to be separated from each other in the left-to-right direction at both ends of the pressing portion 70 in the front-to-back direction and both ends in the left-to-right direction. The front-to-back separation dimension of the positioning ribs 82, 82 facing each other in the front-to-back direction is substantially equal to or slightly larger than the front-to-back dimension of the portion of the second heat transfer portion 40b of the second bus bar 18b where each through hole 50 is formed. Thus, when the second bus bar 18b is overlapped with respect to the pressing portion 70, the second bus bar 18b is positioned between the positioning ribs 82, 82 separated in the front-to-back direction.

[0065] Furthermore, a guided portion 84 is provided on the inner peripheral surface of the upper peripheral wall 64 of the upper housing 58 to guide a guide portion 110, which is described later, provided on the lower housing 60 when the upper housing 58 and the lower housing 60 are assembled. In Embodiment 1, a plurality of guided portions 84 are provided to be separated from each other in the left-right direction at portions on both sides of the inner peripheral surface of the upper peripheral wall 64 in the front-back direction. That is, in the upper housing 58, each guided portion 84 is provided on the outer peripheral side of each locked portion 74.

[0066] Specifically, each guided portion 84 includes a guided portion body 86 formed in a substantially rectangular parallelepiped shape, and is formed with a predetermined left-right dimension and a predetermined front-back dimension. Each guided portion body 86 extends in the up-down direction, which is the assembly direction of the upper housing 58 and the lower housing 60, and each guided portion body 86 protrudes downward from the upper bottom wall 62. The up-down dimension of each guided portion body 86 is substantially equal to the up-down dimension of the upper peripheral wall 64, and the lower end of the guided portion body 86 and the lower end of the upper peripheral wall 64 are at substantially equal positions in the up-down direction.

[0067] Each of the guided portion main bodies 86 is located at a predetermined distance inwardly (inwardly in the front-rear direction in the first embodiment) relative to the upper peripheral wall 64, and the upper peripheral wall 64 and each of the guided portion main bodies 86 are connected by a connecting portion 88. Each connecting portion 88 extends in the upper-lower direction with a smaller dimension in the upper-lower direction than each of the guided portion main bodies 86. In addition, each connecting portion 88 has a smaller dimension in the left-right direction than each of the guided portion main bodies 86, and each connecting portion 88 connects the upper peripheral wall 64 and each of the guided portion main bodies 86 at the central portion in the left-right direction of each of the guided portion main bodies 86.

[0068] <Lower housing 60>

[0069] Also like Figure 6 As shown, the lower housing 60 as a whole is in a generally box-shaped shape that is open upward, and includes a generally rectangular bottom wall 90 extending in the left-right direction and a lower peripheral wall 92 that protrudes upward from the outer peripheral edge of the bottom wall 90. In addition, generally rectangular block-shaped support portions 94a and 94b are provided at both ends in the left-right direction of the lower housing 60 to respectively support the left external connection portion 42 of the first bus bar 18a and the right external connection portion 54 of the third bus bar 18c when the circuit structure 10 is assembled. Thus, when the circuit structure 10 is assembled, the left and right external connection portions 42 and 54 supported by the two support portions 94a and 94b are exposed upward through the two openings 66a and 66b of the upper housing 58.

[0070] It should be noted that nuts not shown in the figure are provided in a roughly buried state on these support portions 94a, 94b, and by overlapping the left and right external connection portions 42, 54 and terminals not shown in the figure provided at the ends of the external wires on the two support portions 94a, 94b and inserting bolts into the two bolt insertion holes 46, 56 and tightening the nuts, the first and third bus bars 18a, 18c and the external wires become conductive.

[0071] In addition, a substantially rectangular upper receiving recess 96 opening upward is provided at a position corresponding to the heat transfer portion 40 of the bus bar 18 on the upper surface of the bottom wall 90. In the first embodiment, since three bus bars (first to third bus bars 18a to 18c) are provided, first to third upper receiving recesses 96a to 96c are provided in the upper surface of the bottom wall 90 at positions corresponding to the first to third heat transfer portions 40a to 40c of the first to third bus bars 18a to 18c, separated from each other in the left-right direction. In addition, as described later, since the heat conduction sheet 24 (first to third heat conduction sheets 24a to 24c) is placed on these first to third upper receiving recesses 96a to 96c, the bottom surfaces of the first to third upper receiving recesses 96a to 96c serve as the placed surfaces 22 (first to third placed surfaces 22a to 22c). It should be noted that the first to third upper receiving recesses 96a to 96c are not essential, and the heat conducting member (for example, the first to third heat conducting sheets 24a to 24c) may also be placed on the upper surface of the bottom wall. In this case, the placement surface may be formed by the upper surface of the bottom wall.

[0072] In addition, if Figure 3 As shown in the figure, a substantially rectangular lower receiving recess 98 opening downward is provided at a position corresponding to the first to third upper receiving recesses 96a to 96c in the lower surface of the bottom wall 90. It should be noted that in the first embodiment, three lower receiving recesses 98 are provided in the lower surface of the bottom wall 90 in correspondence with the first to third upper receiving recesses 96a to 96c and separated from each other in the left-right direction, but in the embodiment 1, the lower receiving recesses 98 are provided in the lower surface of the bottom wall 90 and are separated from each other in the left-right direction. Figure 3 Only the lower receiving recess 98 corresponding to the second upper receiving recess 96b is shown in the figure. By providing the first to third upper receiving recesses 96a to 96c and each lower receiving recess 98 in the bottom wall 90, the bottom wall 90 is thinner than other parts at the positions where the first to third upper receiving recesses 96a to 96c and each lower receiving recess 98 are formed.

[0073] In each of these lower receiving recesses 98, a heat conducting member (heat conducting sheet) not shown, which is the same as the first to third heat conducting sheets 24a to 24c placed on the first to third upper receiving recesses 96a to 96c, is received and fixed. Furthermore, the bottom wall 90 is in thermal contact with a heat sink not shown, such as a vehicle body panel or a battery pack housing, through the heat conducting member (heat conducting sheet) received in each of the lower receiving recesses 98, and the heat generated in the relay 12 and the fuse 14 is dissipated through the heat sink.

[0074] Here, a protrusion 100 protruding upward is provided on the placement surface 22 of the lower housing 60. In the first embodiment, a pair of protrusions 100, 100 protruding upward from the second placement surface 22b is provided in the middle portion in the left-right direction of the middle portion in the front-rear direction of the lower housing 60, and the pair of protrusions 100, 100 are provided to be separated from each other in the left-right direction. In particular, in the first embodiment, each protrusion 100 includes a locking portion 102 that is locked and fitted with each locked portion 74 of the upper housing 58.

[0075] Specifically, each protrusion 100 is substantially cylindrical and can be inserted into each cylindrical portion 76 of the upper housing 58. In the circumferential wall of the cylinder, cutouts separated from each other are provided at multiple locations in the circumferential direction. Therefore, elastic pieces 104 that can be elastically deformed in the radial direction of each protrusion 100 are provided on both sides of each protrusion 100 in the front-back direction. Fitting claws 106 that protrude outward in the front-back direction are provided at the upper ends of each of these elastic pieces 104, and each locking portion 102 of each protrusion 100 is formed by including the elastic piece 104 having each fitting claw 106.

[0076] That is, in the first embodiment, in each protruding portion 100, the elastic pieces 104 having the respective engaging claws 106 are disposed opposite to each other in the front-rear direction. In addition, the upper end surface of each engaging claw 106 is formed as an inclined surface 108, and each inclined surface 108 is inclined in a direction in which the protruding dimension of each engaging claw 106 toward the front-rear direction outward gradually increases as it moves downward.

[0077] In addition, guide portions 110 are provided at positions corresponding to the guided portions 84 of the upper housing 58 in the lower peripheral wall 92 of the lower housing 60. In Embodiment 1, a plurality of guide portions 110 are provided in a manner separated from each other in the left-right direction in portions on both sides in the front-rear direction of the lower peripheral wall 92. That is, in the lower housing 60, each guide portion 110 is provided at the outer peripheral side of each locking portion 102.

[0078] Specifically, if Figure 4 , Figure 6As shown, each guide portion 110 includes a pair of guide wall portions 112, 112 protruding inwardly (inwardly in the front-back direction in the first embodiment) from the inner circumference of the lower peripheral wall 92. These guide wall portions 112 extend in the up-down direction, and in each guide portion 110, the pair of guide wall portions 112, 112 are separated from each other by a left-right dimension that is substantially equal to or slightly larger than the left-right dimension of each guided portion main body 86 of the upper housing 58. In addition, in each guide portion 110, a cutout window 114 is provided in the left-right central portion between the pair of guide wall portions 112, 112, which opens upward in the lower peripheral wall 92 and penetrates in the front-back direction. Each cutout window 114 is formed with a vertical dimension that does not reach the entire length of the lower peripheral wall 92 in the up-down direction. The width dimension of each cutout window 114 (left-right dimension in the first embodiment) is substantially equal to or slightly larger than the left-right dimension of each connecting portion 88 of the upper housing 58.

[0079] Since each guided portion 84 of the upper housing 58 and each guide portion 110 of the lower housing 60 are formed into the above-described shapes, when the upper housing 58 and the lower housing 60 are assembled, each guided portion body 86 is inserted between the pair of guide wall portions 112, 112 in the left-right direction, and each connecting portion 88 is inserted into the cutout window 114. Thus, when the upper housing 58 and the lower housing 60 are assembled, the guide portion 110 is guided in the up-down direction relative to the guided portion 84.

[0080] In particular, by inserting each guided portion body 86 in a substantially pressed state relative to a pair of guide wall portions 112, 112, and inserting each connecting portion 88 in a substantially pressed state relative to each cutout window 114, it is also possible to assemble the upper housing 58 and the lower housing 60 in a mutually fixed state. That is, the fixing mechanism of the upper housing 58 and the lower housing 60 may also be constituted by these each guiding portion 110 and each guided portion 84. It should be noted that the fixing mechanism of the upper housing 58 and the lower housing 60 may also be provided independently of the fixing mechanism implemented by each guiding portion 110 and each guided portion 84, or may be provided in a superimposed manner with the fixing mechanism implemented by each guiding portion 110 and each guided portion 84. For example, as the fixing mechanism of the upper housing 58 and the lower housing 60, a locking fit implemented by each locking portion 102 and each locked portion 74 may also be adopted.

[0081] <Heat conduction member (heat conduction sheet 24)>

[0082] When the circuit structure 10 is assembled, the heat conducting sheet 24 as a sheet-shaped heat conducting member is provided between the heat conducting portion 40 of the bus bar 18 and the bottom wall 90 of the lower housing 60. In the first embodiment, the first to third heat conducting sheets 24a to 24c are accommodated in the first to third upper accommodation recesses 96a to 96c of the bottom wall 90 of the lower housing 60 at positions corresponding to the first to third heat conducting portions 40a to 40c of the first to third bus bars 18a to 18c. Thus, when the circuit structure 10 is assembled, the first to third heat conducting portions 40a to 40c and the bottom wall 90 are in thermal contact via the first to third heat conducting sheets 24a to 24c. It should be noted that the first to third heat conducting sheets 24a to 24c may be fixed to the respective lower surfaces of the first to third heat transfer parts 40a to 40c, may be fixed to the first to third mounting surfaces 22a to 22c of the first to third upper receiving recesses 96a to 96c, or may not be fixed to any one side. In addition, as described above, each lower receiving recess 98 of the bottom wall 90 of the lower housing 60 receives a heat conducting member not shown in the figure, and the heat conducting member is clamped between the bottom wall 90 and the heat sink in the vertical direction.

[0083] The first to third heat conduction sheets 24a to 24c are in the form of sheets flat in the vertical direction and are made of a synthetic resin having a higher thermal conductivity than air. Specifically, silicone resins, non-silicone acrylic resins, ceramic resins, etc. can be used. More specifically, thermally conductive silicone rubber, etc. can be cited. The first to third heat conduction sheets 24a to 24c have flexibility and elasticity and can be elastically deformed in a manner that changes in thickness according to the force applied in the vertical direction. It should be noted that in embodiment 1, as heat conduction components provided on the upper and lower surfaces of the bottom wall 90 of the lower housing 60, sheet-shaped heat conduction components (for example, the first to third heat conduction sheets 24a to 24c) are respectively used, but each heat conduction component is not limited to this scheme, and heat conduction components of any shape can be used. As each heat conduction component, for example, a heat dissipation gap filler or thermal grease made of a silicone resin can also be used.

[0084] It should be noted that there is no limitation on the material of the synthetic resin constituting the housing 20 (upper housing 58 and lower housing 60) and the synthetic resin constituting the heat conduction member (first to third heat conduction sheets 24a to 24c). However, for example, when the lower housing 60 is formed of a nylon-based synthetic resin (e.g., PA6) and the first to third heat conduction sheets 24a to 24c are formed of a silicone-based synthetic resin, peeling is likely to occur between the lower housing 60 and the first to third heat conduction sheets 24a to 24c. Therefore, by adopting these materials, the effect of the present disclosure can be more effectively exerted.

[0085] In particular, the first to third heat conduction sheets 24a to 24c are preferably sandwiched in a compressed state between the first to third heat transfer parts 40a to 40c and the bottom wall 90 of the lower housing 60 in the vertical direction. The first to third heat conduction sheets 24a to 24c can be in close contact with the first to third heat transfer parts 40a to 40c and the bottom wall 90 of the lower housing 60 by being compressed. Thus, the first to third heat conduction sheets 24a to 24c can efficiently transfer heat from the first to third heat transfer parts 40a to 40c to the lower housing 60. Similarly, each heat conduction member provided on the lower surface of the bottom wall 90 of the lower housing 60 is preferably sandwiched in a compressed state between the bottom wall 90 and the heat sink in the vertical direction. Thus, each heat conduction member can be in close contact with the bottom wall 90 and the heat sink, and can efficiently transfer heat from the lower housing 60 to the heat sink.

[0086] Here, the thermally conductive sheet 24 is provided with through holes 116 through which the protrusions 100 provided on the lower case 60 are inserted. In the first embodiment, since the pair of protrusions 100, 100 are provided on the second mounted surface 22b of the lower case 60, the second thermally conductive sheet 24b mounted on the second mounted surface 22b is provided with a pair of through holes 116, 116. These through holes 116 are provided at a substantially central portion of the second thermally conductive sheet 24b in the front-rear direction and are separated from each other in the left-right direction.

[0087] like Figure 3 As shown, the inner diameter of each through hole 116 is substantially equal to the inner diameter of each through hole 50 provided in the second bus bar 18b. That is, the inner diameter of each through hole 116 is substantially equal to or slightly smaller than the maximum outer diameter of the portion where each engaging claw 106 provided at the upper end of each protrusion 100 of the lower housing 60 is formed, and is substantially equal to or slightly larger than the outer diameter of the portion where each engaging claw 106 is not formed in each protrusion 100.

[0088] Thus, when the circuit structure 10 is assembled, the protrusions 100 of the lower case 60 are inserted through and engaged with the through holes 116 of the second heat conducting sheet 24b, and the displacement of the second heat conducting sheet 24b relative to the lower case 60 is restricted. Therefore, in the first embodiment, the displacement restricting portion 118 provided on the case 20 and engaging with the heat conducting sheet 24 to restrict the displacement of the heat conducting sheet 24 is configured to include the protrusions 100.

[0089] <Assembly Step of Circuit Structure 10>

[0090] Next, a specific example of the assembly process of the circuit structure 10 will be described. It should be noted that the assembly process of the circuit structure 10 is not limited to the following description.

[0091] First, prepare the upper housing 58, the lower housing 60, the relay 12, the fuse 14, the first to third bus bars 18a to 18c, the bolts 36, the first to third heat conducting sheets 24a to 24c, etc. Then, the relay 12 is placed on the upper bottom wall 62 of the upper housing 58 that has been turned upside down, and the relay 12 is bolted to the upper housing 58 using bolts inserted through the legs 30.

[0092] After that, the first and second bus bars 18a and 18b are placed from above the relay 12, and the first and second connection portions 16a and 16b of the relay 12 and the bolt insertion holes 44 of the first and second bus bars 18a and 18b are aligned in the front-to-back direction. It should be noted that when the second bus bar 18b is placed on the relay 12, the second heat transfer portion 40b of the second bus bar 18b overlaps with the pressing portion 70 of the upper housing 58 from above, and the second bus bar 18b is positioned in the front-to-back direction relative to the upper housing 58 by the positioning ribs 82 provided on the pressing portion 70.

[0093] Next, the bolts 120 are inserted from the front into the first and second connection portions 16a, 16b and the bolt insertion holes 44 and tightened. Thus, the relay 12 and the first and second bus bars 18a, 18b are fixed. In the state where the second bus bar 18b is fixed to the relay 12 (upper housing 58) in this way, the inner holes of the cylindrical portions 76 of the pressing portion 70 and the through holes 50 of the second bus bar 18b are aligned with each other and communicated in the vertical direction.

[0094] Next, the third bus bar 18c is placed on the upper bottom wall 62 of the upper housing 58, the third and fourth connecting portions 16c, 16d of the fuse 14 are overlapped with the respective fuse connecting portions 48 of the second and third bus bars 18b, 18c, and the fuse 14 is placed on the second and third bus bars 18b, 18c. Thus, the bolt insertion holes 52 of each fuse connecting portion 48 and the bolt insertion holes 34 of the third and fourth connecting portions 16c, 16d are aligned. Then, the bolts 36 are inserted into the respective bolt insertion holes 34, 52 and tightened. Thus, in addition to the relay 12 and the first and second bus bars 18a, 18b, the fuse 14 and the third bus bar 18c are fixed to the upper housing 58.

[0095] The upper housing 58 is turned upside down and arranged to face the lower housing 60 from above. It should be noted that the heat conducting sheets 24 (first to third heat conducting sheets 24a to 24c) are fixed and placed on the bottom surfaces of the first to third upper side receiving recesses 96a to 96c of the lower housing 60 (first to third load surfaces 22a to 22c) in advance by adhesive or the like. Thus, the protrusions 100 of the lower housing 60 are inserted through and engaged with the through holes 116 of the second heat conducting sheet 24b. Then, the guided portions 84 of the upper housing 58 are inserted into the guide portions 110 of the lower housing 60. Thus, the inner holes and through holes 50 of the cylindrical portions 76 that are connected to each other on the upper housing 58 side and the protrusions 100 that penetrate the through holes 116 of the second heat conducting sheet 24b on the lower housing 60 side are positioned in a state of facing each other in the vertical direction. That is, each locked portion 74 provided in each cylindrical portion 76 and each locking portion 102 provided in each protruding portion 100 are positioned in a state of facing each other in the up-down direction.

[0096] Then, each guide portion 110 is guided along each guided portion 84, so that the upper housing 58 and the lower housing 60 approach each other in the vertical direction. As a result, each inclined surface 80 provided on each locked portion 74 and each inclined surface 108 provided on each locking portion 102 abut against each other in the vertical direction, and each elastic piece 104 of each locking portion 102 is elastically deformed radially inward. As a result, each protrusion 100 is allowed to be inserted into each cylindrical portion 76, each through hole 50, and each through hole 116. Then, each engaging claw 106 of each locking portion 102 passes over each engaged claw 78 of each locked portion 74, and each elastic piece 104 is elastically restored and deformed, and each engaging claw 106 is locked to each engaged claw 78. As a result, each guided portion 84 is inserted relative to each guide portion 110 in a substantially pressed state, and each locking portion 102 and each locked portion 74 are locked and engaged, so that the upper housing 58 and the lower housing 60 are fixed to each other. As a result, the circuit structure 10 is completed. In the completed state of the circuit structure 10, the second bus bar 18b and the second thermally conductive sheet 24b overlap in the vertical direction, and the protrusions 100 are inserted into the overlapping through holes 50 and through holes 116.

[0097] The circuit structure 10 assembled in this way is overlapped with a heat sink such as a vehicle body panel or a battery pack case (not shown) and fixed by bolts or the like. As a result, for example, a heat conduction member (not shown) provided on the lower surface of the bottom wall 90 of the lower housing 60 can be compressed between the lower housing 60 and the heat sink in the vertical direction. In addition, the heat generated in the relay 12 and the fuse 14 accompanying power-on is dissipated from the heat sink (not shown) via the first to third heat transfer portions 40a to 40c of the first to third bus bars 18a to 18c overlapped in the vertical direction, the first to third heat conduction sheets 24a to 24c, the bottom wall 90 of the lower housing 60, and the heat conduction member (not shown) provided on the lower surface of the bottom wall 90.

[0098] In the circuit structure 10 of the first embodiment, the displacement limiting portion 118 that engages with the second heat conducting sheet 24b and limits the displacement of the second heat conducting sheet 24b is provided in the lower housing 60 constituting the housing 20. Thus, even when the housing 20 is exposed to a high temperature environment and expands or contracts, or when a large impact is applied from the outside, it is possible to suppress the generation of a gap between the lower housing 60 and the second heat conducting sheet 24b, and to stably exert a desired heat dissipation effect. In particular, when the lower housing 60 is formed of a material having a higher thermal conductivity than the upper housing 58, the lower housing 60 and the upper housing 58 are likely to be relatively displaced due to the difference in linear expansion coefficient in a high temperature environment. Even in this case, the stress generated at the interface between the second heat conducting sheet 24b and the lower housing 60 is advantageously reduced by the displacement limiting portion 118, and the desired heat dissipation effect of the circuit structure 10 can be maintained.

[0099] More specifically, in the first embodiment, the displacement limiting portion 118 is configured to include the protrusions 100 of the lower housing 60, and the protrusions 100 (the locking portions 102) and the cylindrical portions 76 (the locked portions 74) of the upper housing 58 are locked and fitted with each other. As a result, the upper housing 58 and the lower housing 60 are restrained from relative displacement in any of the front-to-back direction, the left-to-right direction, and the up-to-down direction. Therefore, the second heat conducting sheet 24b sandwiched between the upper housing 58 and the lower housing 60 is restrained from displacement in any of the front-to-back direction, the left-to-right direction (i.e., the shear direction), and the up-to-down direction (tensile direction) relative to the housing 20 (the upper housing 58 and the lower housing 60), and the desired heat dissipation effect can be exerted.

[0100] The displacement restricting portion 118 includes protrusions 100 protruding upward from the second mounting surface 22b of the lower housing 60, and the protrusions 100 are inserted through the through holes 50 provided in the second bus bar 18b and the through holes 116 provided in the second heat conducting sheet 24b. By adopting the structure in which the protrusions 100 are inserted through the through holes 116 of the second heat conducting sheet 24b, the displacement restricting effect of the second heat conducting sheet 24b relative to the lower housing 60 can be stably obtained. In addition, in the first embodiment, the through holes 50 (i.e., the locked portions 74 and the locking portions 102) are provided near the bolt fastening points (bolt insertion holes 44 and 52) in the second bus bar 18b where external force is easily applied. Thus, the second bus bar 18b can be prevented from being deformed in a rotating manner at the bolt fastening points due to impact, difference in linear expansion coefficient, etc. As a result, the second heat conducting sheet 24b sandwiched between the second bus bar 18b and the lower housing 60 can also be prevented from being displaced relative to the housing 20. It should be noted that the through holes of the bus bar (i.e., the locking structure realized by the locked portion and the locking portion) can also be provided at two locations of the bus bar away from the rotation axis of the bolt fastening point (bolt insertion hole) in a manner facing each other with the rotation axis sandwiched therebetween. In this way, displacement of the bus bar in the rotation direction relative to the housing can be more effectively prevented.

[0101] In particular, the housing 20 is composed of an upper housing 58 and a lower housing 60, and the upper housing 58 and the lower housing 60 have respective locked portions 74 and respective locking portions 102 that are locked and fitted with each other. Thus, even when an external force in a vertical separation direction opposite to the assembly direction is applied to the upper housing 58 and the lower housing 60, relative displacement between the second bus bar 18b on the upper housing 58 side and the lower housing 60 can be suppressed, and the second heat conducting sheet 24b sandwiched therebetween can be prevented from being peeled off from the second bus bar 18b and the lower housing 60.

[0102] The upper housing 58 is provided with positioning ribs 82 for positioning the second bus bar 18b at the pressing portion 70. Thus, when the second bus bar 18b to which the second heat conducting sheet 24b is fixed is assembled to the upper housing 58, the second bus bar 18b can be quickly aligned with respect to the upper housing 58. In addition, after the second heat conducting sheet 24b and the second bus bar 18b are assembled to the upper housing 58, the positional displacement of the inner holes of the cylindrical portions 76, the through holes 50, and the through holes 116 can be effectively prevented, so that the insertion of the protrusions 100 into the cylindrical portions 76, the through holes 50, and the through holes 116 can be stably achieved.

[0103] In particular, the upper housing 58 is provided with each guided portion 84, and the lower housing 60 is provided with each guide portion 110. When the upper housing 58 and the lower housing 60 are assembled, the locking portions 102 and the locked portions 74 are positioned relative to each other in the vertical direction in a state where the guide portions 110 are inserted into the guided portions 84. Thus, while the insertion state of each guide portion 110 into each guided portion 84 is maintained, each locking portion 102 is locked to each locked portion 74 by bringing the upper housing 58 and the lower housing 60 closer to each other, so that the locking portions 102 and the locked portions 74 can be stably engaged.

[0104] The upper housing 58 has a pressing portion 70, and the second bus bar 18b and the second heat conducting sheet 24b are sandwiched between the pressing portion 70 and the lower housing 60. In addition, each locked portion 74 is provided on the pressing portion 70, and each locked portion 74 is engaged with each locking portion 102 of the lower housing 60. That is, the second bus bar 18b and the second heat conducting sheet 24b are sandwiched between the upper housing 58 and the lower housing 60 in the vertical direction near each locking portion 102 and each locked portion 74 that realize the locking of the upper housing 58 and the lower housing 60. Therefore, it is possible to effectively prevent the generation of a gap between the second heat conducting sheet 24b and the lower housing 60 accompanying the separation displacement of the upper housing 58 and the lower housing 60 in the vertical direction.

[0105] <Implementation Method 2>

[0106] Below, while referring to Figure 7~Figure 9 While explaining Embodiment 2 of the present disclosure. The circuit structure 130 of Embodiment 2 has the same basic structure as the circuit structure 10 of Embodiment 1, but the structures of the cylindrical portion 134 of the upper shell 132 and the protruding portion 138 of the lower shell 136 are different. Therefore, in the following description, the difference from the circuit structure 10 in Embodiment 1 is explained, and the same reference numerals as those in Embodiment 1 are marked in the figure for the components and parts that are substantially the same as those in Embodiment 1, and the detailed description is omitted.

[0107] <Upper housing 132>

[0108] In the upper housing 132 of the second embodiment, as in the upper housing 58 of the first embodiment, a pressing portion 70 is provided that protrudes downward from the middle portion in the left-right direction of the upper bottom wall 62. In the pressing portion 70, as in the first embodiment, a plurality of lightening holes 72 are provided, and a cylindrical portion 134 is provided in the lightening holes 72 in the middle portion in the front-rear direction of the pressing portion 70. In the second embodiment, a pair of cylindrical portions 134, 134 are provided, and the pair of cylindrical portions 134, 134 are separated from each other in the left-right direction.

[0109] Here, in each cylindrical portion 76 of the first embodiment, each engaged claw 78 protruding toward the inner circumference is provided to constitute each locked portion 74, but the inner diameter dimension of each cylindrical portion 134 of the second embodiment is substantially constant over the entire length range in the vertical direction. As described later, each protrusion 138 of the lower housing 136 is pressed into the inner hole of each cylindrical portion 134, so in the second embodiment, the inner hole of each cylindrical portion 134 constitutes a pressed hole 140.

[0110] <Lower housing 136>

[0111] In the lower housing 136 of the second embodiment, a protrusion 138 protruding upward is provided at the front-rear center of the second placement surface 22b, similarly to the lower housing 60 of the first embodiment. In the second embodiment, a pair of protrusions 138, 138 are provided, and the pair of protrusions 138, 138 are separated from each other in the left-right direction.

[0112] Here, in each protrusion 100 of the first embodiment, each elastic piece 104 and each engaging claw 106 are provided to constitute each locking portion 102, but the outer diameter dimension of each protrusion 138 of the second embodiment is substantially constant over the entire length range in the vertical direction. The outer diameter dimension of each protrusion 138 is substantially equal to or slightly larger than the inner diameter dimension of each cylindrical portion 134 (each pressed-in hole 140) of the upper housing 132, and each protrusion 138 is pressed into each pressed-in hole 140 when the upper housing 132 and the lower housing 136 are assembled. That is, in the second embodiment, each protrusion 138 is configured to include a press-in protrusion 142.

[0113] Therefore, in the second embodiment, the upper housing 132 and the lower housing 136 are fixed by the press-fit structure of each press-fit protrusion 142 into each press-fit hole 140 (and the press-fit structure of each guided portion 84 into each guide portion 110 as required). At this time, each protrusion 138 is inserted through and engaged with each through hole 116 of the second heat conducting sheet 24b in advance, thereby limiting the relative displacement of the lower housing 136 and the second heat conducting sheet 24b. As a result, in the second embodiment, the displacement limiting portion 144 that limits the displacement of the second heat conducting sheet 24b is formed including each protrusion 138.

[0114] Thus, in the circuit structure 130 of the second embodiment, only the fixing structure of the upper case 132 and the lower case 136 is different from that of the circuit structure 10 of the first embodiment, and thus the same effect as that of the circuit structure 10 of the first embodiment can be achieved. In addition, in the second embodiment, the pressing portion 70 is provided with the press-in holes 140 into which the press-in protrusions 142 of the lower case 136 are press-in. Thus, in the second embodiment as well, the second bus bar 18b and the second heat conducting sheet 24b are sandwiched between the upper case 132 and the lower case 136 in the vertical direction near the press-in holes 140 and the press-in protrusions 142 that realize the fixing of the upper case 132 and the lower case 136. Therefore, the generation of a gap between the second heat conducting sheet 24b and the lower case 136 accompanying the vertical separation displacement of the upper case 132 and the lower case 136 can be effectively prevented.

[0115] <Implementation Method 3>

[0116] Below, while referring to Figure 10~Figure 12 While explaining the third embodiment of the present disclosure. The circuit structure 150 of the third embodiment has the same basic structure as the circuit structure 10 of the first embodiment and the circuit structure 130 of the second embodiment, but the structure of the displacement limiting portion 152 is different from that of the first and second embodiments. Therefore, in the following description, the differences from the first and second embodiments are described, and the detailed description is omitted by marking the components and parts that are substantially the same as those of the first and second embodiments with the same figure marks as those of the first and second embodiments. It should be noted that in the third embodiment, three bus bars 18 (first to third bus bars 18a to 18c) are provided in the same manner as in the first and second embodiments, and the second heat conduction sheet 24b overlapping the second bus bar 18b is divided into two in the left-right direction, and a left second heat conduction sheet 154a and a right second heat conduction sheet 154b are provided. Fig.11 , 12 In FIG. 1 , in addition to the first to third bus bars 18 a to 18 c , each heat conducting sheet 24 (the first and third heat conducting sheets 24 a and 24 c , and the left and right second heat conducting sheets 154 a and 154 b ) is indicated by a two-dot chain line.

[0117] <Upper housing 156>

[0118] In the upper housing 156 of the third embodiment, as in the upper housing 58 of the first embodiment, a pressing portion 70 is provided that protrudes downward from the middle portion of the upper bottom wall 62 in the left-right direction. In addition, in the third embodiment, insertion grooves 158 that open outward in the front-rear direction and extend in the up-down direction are provided on both sides of the outer peripheral surface of the pressing portion 70 in the front-rear direction. In particular, in the third embodiment, the insertion grooves 158 are provided at two locations separated in the left-right direction on both sides of the pressing portion 70 in the front-rear direction, and a total of four insertion grooves 158 are provided in the pressing portion 70.

[0119] Each insertion groove 158 is a roughly rectangular cross-section having a predetermined width dimension (left-right dimension) and depth dimension (front-back dimension). The depth dimension of each insertion groove 158 is larger than the width dimension (front-back dimension) of each positioning rib 82 provided at both ends of the pressing portion 70 in the front-back direction, and thus, the bottom surface of each insertion groove 158 is located inward of each positioning rib 82 in the front-back direction. As a result, when the second bus bar 18b is overlapped with the pressing portion 70, the lower opening of each insertion groove 158 is partially covered by both ends of the second bus bar 18b in the front-back direction. In other words, when the second bus bar 18b is overlapped with the pressing portion 70, both ends of the second bus bar 18b in the front-back direction protrude outward from the bottom surface of each insertion groove 158 in the front-back direction.

[0120] It should be noted that, as described above, in the third embodiment, the second heat-conducting sheet 24b is divided in the left-right direction, and the left second heat-conducting sheet 154a and the right second heat-conducting sheet 154b are provided, which are separated from each other in the left-right direction. Here, the left second heat-conducting sheet 154a overlaps with the left portion of the second bus bar 18b (a portion located to the left of the pressing portion 70 and located below the relay 12). In addition, the right second heat-conducting sheet 154b overlaps with the portion of the second bus bar 18b corresponding to the left-right direction between the insertion grooves 158, 158 separated in the left-right direction. That is, when the circuit structure 150 is assembled, the left and right second heat-conducting sheets 154a, 154b are provided at positions offset from the insertion grooves 158 in the left-right direction.

[0121] <Lower housing 160>

[0122] In the third embodiment, since the second heat conducting sheet 24b is divided in the left-right direction to provide the left and right second heat conducting sheets 154a and 154b, the second upper side receiving recess 96b for receiving the second heat conducting sheet 24b is also divided in the left-right direction to provide the left second receiving recess 162a and the right second receiving recess 162b in the bottom wall 90 of the lower housing 160. That is, the left second heat conducting sheet 154a is received in the left second receiving recess 162a, and the right second heat conducting sheet 154b is received in the right second receiving recess 162b. In short, the bottom surfaces of the left second receiving recess 162a and the right second receiving recess 162b are respectively used as the left second placed surface 164a and the right second placed surface 164b.

[0123] In addition, elastic locking pieces 166 protruding upward are provided at positions corresponding to the insertion grooves 158 of the upper housing 156 in the periphery of the right second mounted surface 164b. That is, the elastic locking pieces 166 are provided at two locations separated in the left-right direction on both sides of the right second mounted surface 164b in the front-rear direction, and a total of four elastic locking pieces 166 are provided in the lower housing 160. It should be noted that, as described above, since the right second heat conducting piece 154b is provided between the insertion grooves 158 separated in the left-right direction in the left-right direction, the right second heat conducting piece 154b is accommodated between the elastic locking pieces 166 separated in the left-right direction in the right second accommodation recess 162b (right second mounted surface 164b).

[0124] Each elastic locking piece 166 includes a flexure piece 168 that protrudes upward from the bottom wall 90 of the lower housing 160 and can be elastically deformed toward both sides in the front-rear direction, which is the outer peripheral side of the right second heat conducting piece 154b, and a locking claw portion 170 that is provided at the protruding end (upper end) of the flexure piece 168 and protrudes inward in the front-rear direction. The upper end surface of each locking claw portion 170 is formed as an inclined surface 172 that gradually inclines inward in the left-right direction as it moves downward.

[0125] When the upper housing 156 and the lower housing 160 having the above-described structure are assembled, the upper housing 156 to which the components are fixed is arranged to face the lower housing 160 from above. Then, the upper housing 156 and the lower housing 160 are brought close to each other in the vertical direction according to the guiding action of the guide portions 110 and the guided portions 84. Thus, the insertion grooves 158 of the upper housing 156 and the elastic locking pieces 166 of the lower housing 160 face each other in the vertical direction, and the inclined surfaces 172 of the elastic locking pieces 166 abut against both ends in the front-rear direction of the second bus bar 18b protruding in a manner covering the lower opening of the insertion grooves 158. Then, by further bringing the upper housing 156 and the lower housing 160 close to each other in the vertical direction, the flexure pieces 168 of the elastic locking pieces 166 are elastically deformed outward in the front-rear direction. Each of these elastic locking pieces 166 elastically restores its deformation when each locking claw portion 170 passes over the second bus bar 18b, and each locking claw portion 170 is locked to both ends of the second bus bar 18b in the front-rear direction. Thus, the upper housing 156 and the lower housing 160 are fixed by the locking mechanism realized by each elastic locking piece 166 (each locking claw portion 170) (and the pressing structure of each guided portion 84 into each guide portion 110 as required), and the circuit structure 150 is completed.

[0126] In the third embodiment, each locking claw 170 is engaged with the edge of the second bus bar 18b overlapping the right second heat conducting sheet 154b. That is, each elastic locking piece 166 provided on the lower housing 160 is engaged with the second bus bar 18b fixed to the upper housing 156 side, and the right second heat conducting sheet 154b is sandwiched between these second bus bars 18b and the bottom wall 90 of the lower housing 160 in the vertical direction. By the locking of each elastic locking piece 166 to the second bus bar 18b in this way, the displacement of the right second heat conducting sheet 154b sandwiched between the second bus bar 18b and the bottom wall 90 is restricted, and in the third embodiment, the displacement restricting portion 152 is constituted by including each elastic locking piece 166.

[0127] In the circuit structure 150 of the third embodiment, since the displacement of the right second heat conducting sheet 154b relative to the lower housing 160 is limited by providing the displacement limiting portion 152, the same effect as the circuit structure 150 of the first embodiment can be achieved. In particular, in the third embodiment, the elastic locking pieces 166 constituting the displacement limiting portion 152 are not inserted into the second bus bar 18b as in the first and second embodiments, but are locked to both ends of the second bus bar 18b in the front-rear direction. Therefore, it is not necessary to provide a through hole in the second bus bar 18b for inserting the displacement limiting portion 152 (the elastic locking pieces 166), and deterioration of the conduction performance can be avoided.

[0128] <Other Embodiments>

[0129] 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.

[0130] (1) In the above embodiment, the busbar 18 for power supply (first to third busbars 18a to 18c) has a heat transfer portion 40 (first to third heat transfer portions 40a to 40c), and a busbar for power supply and heat transfer is used as the busbar 18, but a busbar for power supply and a busbar for heat transfer may be used separately. In this case, the busbar for power supply and the busbar for heat transfer may be fastened together with bolts relative to the connection portion of the heat generating component (for example, a relay, a fuse). In addition, when the busbar for power supply and the busbar for heat transfer are provided separately, a through hole as in the above embodiments 1 and 2 may be provided in the heat transfer busbar that clamps the heat conducting member (for example, a heat conducting sheet) between the lower housing, or a structure for elastic locking sheet locking as in the above embodiment 3 may be adopted, and no special structure is required in the busbar for power supply.

[0131] (2) In the above embodiment, each guided portion 84 of the upper housing 58, 132, 156 is inserted into each guide portion 110 of the lower housing 60, 136, 160 in a substantially pressed-in state, which helps to fix the upper housing 58, 132, 156 and the lower housing 60, 136, 160, but the present invention is not limited to such a scheme. The upper housing and the lower housing may also be fixed by at least one of the following structures: the locking engagement between the locking portion and the locked portion as in the above embodiment 1, the pressing structure of the pressing protrusion into the pressed-in hole as in the above embodiment 2, and the structure of locking the elastic locking piece provided on the lower housing to the bus bar fixed to the upper housing as in the above embodiment 3.

[0132] That is, the guiding part and the guided part may not have the function of fixing the upper shell and the lower shell, and may only have the function of guiding the upper shell and the lower shell in a direction close to each other when the upper shell and the lower shell are assembled. In addition, a locking mechanism for fixing the upper shell and the lower shell may be provided independently of the guiding part and the guided part in the upper peripheral wall of the upper shell and the lower peripheral wall of the lower shell. It should be noted that the guiding part and the guided part are not necessary in the circuit structure disclosed in the present invention.

[0133] (3) In the above embodiment, a plurality of heat-conducting sheets 24 are provided as heat-conducting members, and in the first and second embodiments, the displacement of the second heat-conducting sheet 24b relative to the lower housing 60, 136 is limited by the displacement limiting portion 118, 144, and in the third embodiment, the displacement of the right second heat-conducting sheet 154b relative to the lower housing 160 is limited by the displacement limiting portion 152, but the present invention is not limited to this embodiment. For example, the displacement of two or more of the plurality of heat-conducting members (e.g., heat-conducting sheets) provided relative to the housing may be limited by the displacement limiting portion.

[0134] In addition, the heat-conducting member whose displacement relative to the housing is not restricted by the displacement restricting portion among the plurality of heat-conducting members is not limited to the scheme in which the heat-conducting portion of the busbar and the lower housing are clamped in the vertical direction as in the above-described embodiment. That is, for example, a through window penetrating in the thickness direction may be provided in the bottom wall of the lower housing, and the heat-conducting portion may be in direct thermal contact with the heat sink through the through window or in thermal contact with the heat sink via the heat-conducting member.

[0135] (4) In the third embodiment, the locking claws 170 of each elastic locking piece 166 are locked to both ends of the second bus bar 18b in the front-rear direction, but the present invention is not limited to this scheme. That is, for example, the locking claws of the elastic locking piece may be locked to the pressing portion of the upper housing that presses the bus bar (for example, the second bus bar) from above.

[0136] (5) In the first embodiment, a pair of protrusions 100, 100 are provided in the lower housing 60 and a locking portion 102 is provided in each protrusion 100, and in the second embodiment, a pair of protrusions 138, 138 are provided in the lower housing 136 and a press-fit protrusion 142 is provided in each protrusion 138, but the present invention is not limited to this scheme. For example, when a plurality of protrusions are provided, the scheme of the first embodiment and the scheme of the second embodiment may be combined and adopted, and the scheme of the third embodiment may also be combined and adopted. That is, with respect to the schemes described in the first to third embodiments, at least two of them may be combined and adopted.

[0137] (6) In the above embodiment, the displacement limiting parts 118, 144, 152 are all provided on the lower shell 60, 136, 160 constituting the shell 20, but they may be provided on the upper shell, for example. That is, for example, the protrusion constituting the displacement limiting part may be provided on the upper shell, and the locked part that is locked and engaged with the locking part of the protrusion may be provided on the lower shell, or the pressed hole into which the press-in protrusion of the protrusion is pressed may be provided on the lower shell. Alternatively, the elastic locking piece constituting the displacement limiting part may be provided on the upper shell, and the elastic locking piece may be engaged with the edge of the bus bar fixed to the lower shell. In addition, in the above embodiment, when the upper housing 58, 132, 156 and the lower housing 60, 136, 160 are assembled, the relay 12, the fuse 14, and the bus bar 18 (the first to third bus bars 18a to 18c) are assembled to the upper housing 58, 132, 156 side and the upper housing 58, 132, 156 is assembled to the lower housing 60, 136, 160, and the relay 12, the fuse 14, and the bus bar 18 (the first to third bus bars 18a to 18c) are also fixed relative to the lower housing 60, 136, 160, but the present invention is not limited to this scheme. That is, the heat generating components (for example, relays, fuses) and the bus bar can also be assembled on the lower housing side, and the heat generating components and the bus bar can also be fixed relative to the upper housing by assembling the upper housing to the lower housing.

[0138] (7) In the third embodiment, the second heat conducting sheet 24b is divided in the left-right direction to form the left and right second heat conducting sheets 154a and 154b, and the left and right second heat conducting sheets 154a and 154b are arranged so that the positions of the elastic locking pieces 166 are staggered, but the present invention is not limited to this scheme. That is, in the third embodiment, the second heat conducting sheet 24b formed in the same shape as in the first and second embodiments may be adopted. In this case, the displacement of the second heat conducting sheet 24b in the front-rear direction may be restricted by the flexure pieces of the elastic locking pieces.

[0139] (8) In the above embodiment, it is assumed that each heat conducting sheet 24 (first to third heat conducting sheets 24a to 24c, left and right second heat conducting sheets 154a, 154b) is fixed in advance to the mounting surface 22 (first to third mounting surfaces 22a to 22c, left and right second mounting surfaces 164a, 164b) of the bottom wall 90 of the lower case 60, 136, 160, but the present invention is not limited to this embodiment. That is, for example, each heat conducting member may be fixed in advance to the lower surface of each heat transfer portion of each bus bar.

[0140] (9) In the above-described embodiment, the displacement limiting portions 118, 144, 152 are provided to suppress the displacement of the second heat conducting sheet 24b relative to the housing 20 in each of the front-to-back direction, the left-to-right direction (shear direction), and the up-to-down direction (tensile direction), but the present invention is not limited to this embodiment. In the circuit structure according to the present disclosure, the displacement limiting portions may be used to limit the displacement of the heat conducting member relative to the housing in at least one of the front-to-back direction, the left-to-right direction, and the up-to-down direction.

[0141] Description of Reference Numerals

[0142] 10 Circuit Structure (Embodiment 1)

[0143] 12 Relay (heat generating component)

[0144] 14 Fuse (heat generating component)

[0145] 16 Connection

[0146] 16a First connecting portion

[0147] 16b Second connection portion

[0148] 16c Third connection part

[0149] 16d Fourth connecting portion

[0150] 18 Busbar

[0151] 18a First busbar

[0152] 18b Second bus bar

[0153] 18c Third bus

[0154] 20 Housing

[0155] 22 Loading surface

[0156] 22a First mounting surface

[0157] 22b Second mounting surface

[0158] 22c Third mounting surface

[0159] 24 Heat conduction sheet (heat conduction member)

[0160] 24a First heat conduction sheet

[0161] 24b Second heat conduction sheet

[0162] 24c Third heat transfer sheet

[0163] 26 Relay body

[0164] 28 Insulation board

[0165] 30 Legs

[0166] 32 Fuse body

[0167] 34 Bolt insertion hole

[0168] 36 Bolts

[0169] 38 Relay connection

[0170] 38a First relay connection part

[0171] 38b Second relay connection

[0172] 40 Heat transfer unit

[0173] 40a First heat transfer section

[0174] 40b Second heat transfer section

[0175] 40c Third heat transfer section

[0176] 42 Left external connection

[0177] 44, 46 Bolt insertion holes

[0178] 48 Fuse connection

[0179] 50 Through hole

[0180] 52 Bolt insertion hole

[0181] 54 Right external connection

[0182] 56 Bolt insertion hole

[0183] 58 Upper shell

[0184] 60 Lower housing

[0185] 62 Upper bottom wall

[0186] 64 Zhou Bi

[0187] 66a, 66b opening

[0188] 68 incision

[0189] 70 Pressing part

[0190] 72 weight reduction holes

[0191] 74 Locked part

[0192] 76 cylindrical part

[0193] 78 Engaged claw

[0194] 80 Inclined surface

[0195] 82 Positioning ribs

[0196] 84 Guided Department

[0197] 86 Guided part body

[0198] 88 Connection

[0199] 90 bottom wall

[0200] 92 Lower wall

[0201] 94a, 94b Supporting part

[0202] 96 Upper side storage recess

[0203] 96a First upper side storage recess

[0204] 96b Second upper receiving recess

[0205] 96c Third upper receiving recess

[0206] 98 Lower side receiving recess

[0207] 100 Protrusion

[0208] 102 Locking part

[0209] 104 elastic sheet

[0210] 106 Fitting claw

[0211] 108 Inclined surface

[0212] 110 Guidance Department

[0213] 112 guide wall

[0214] 114 Cutout Window

[0215] 116 Through hole

[0216] 118 Displacement limiting part

[0217] 120 Bolt

[0218] 130 Circuit Structure (Implementation 2)

[0219] 132 Upper shell

[0220] 134 cylindrical part

[0221] 136 Lower housing

[0222] 138 Protrusion

[0223] 140 pressed into hole

[0224] 142 Press-in protrusion

[0225] 144 Displacement limiting part

[0226] 150 Circuit Structure (Implementation Method 3)

[0227] 152 Displacement limiting unit

[0228] 154a Second heat conduction sheet on the left

[0229] 154b Second heat conduction sheet on the right

[0230] 156 Upper housing

[0231] 158 Insert slot

[0232] 160 Lower housing

[0233] 162a Second receiving recess on the left side

[0234] 162b Right side second receiving recess

[0235] 164a Left second placement surface

[0236] 164b Right side second placement surface

[0237] 166 elastic locking piece

[0238] 168 Flexure

[0239] 170 Locking claw

[0240] 172 Inclined surface.

Claims

1. A circuit structure comprising: Heat generating components; A bus bar connected to a connecting portion of the heat generating component; a housing for accommodating the heat generating component and the bus bar; and a heat conducting member mounted on the mounting surface of the housing, in thermal contact with the housing and the bus bar and sandwiched therebetween, The housing includes a displacement restricting portion that engages with the heat conduction member to restrict displacement of the heat conduction member.

2. The circuit structure according to claim 1, The displacement restricting portion includes a protruding portion protruding from the placement surface of the housing, The heat conducting member has a through hole through which the protrusion is inserted. The bus bar has a through hole that overlaps with the through hole and through which the protrusion is inserted.

3. The circuit structure according to claim 2, The housing includes a lower housing having the placement surface and an upper housing assembled with the lower housing with the heat conduction member and the bus bar sandwiched therebetween. The upper housing has a locked portion, The protrusion includes a locking portion which is provided on the lower housing and is locked and engaged with the locked portion.

4. The circuit structure according to claim 3, The upper housing has a positioning rib for positioning the bus bar. The bus bar is positioned by being engaged with the positioning rib, and the locked portion of the upper case is positioned at the through hole of the bus bar, the through hole of the heat conduction member, and the locking portion inserted through the through hole and the through hole.

5. The circuit structure according to claim 3 or 4, The lower housing and the upper housing respectively include a guide portion and a guided portion arranged on the outer peripheral sides of the locking portion and the locked portion. When the upper housing is assembled to the lower housing, the guided portion is guided in advance by the guiding portion, so that the locked portion of the upper housing is positioned at the locking portion of the lower housing.

6. The circuit structure according to claim 2, The housing includes a lower housing having the placement surface and an upper housing assembled with the lower housing with the heat conduction member and the bus bar sandwiched therebetween. The upper housing has a pressed-in hole, The protrusion includes a press-in protrusion provided on the lower housing and pressed into the press-in hole.

7. The circuit structure according to claim 1 or 2, The displacement limiting portion has an elastic locking piece protruding from the peripheral edge of the placement surface of the housing. The elastic locking piece includes a flexible piece that can be elastically deformed toward the outer peripheral side of the heat conducting member and a locking claw portion provided at a protruding end of the flexible piece. The locking claw portion is engaged with an edge portion of the bus bar overlapping the heat conduction member.

8. The circuit structure according to claim 3 or 4, The upper case has a pressing portion for bringing the bus bar into contact with the heat conduction member. The locked portion is provided on the pressing portion.

Images