Circuit construct

Abstract

To provide a circuit construct that can reduce stress generated at the interface between a heat conductive member and a case.SOLUTION: A circuit construct 10 includes heat generating portions 12 and 14, a bus bar 18 connected to the connection portion 16 of the heat generating parts 12 and 14, a case 20 that accommodates the heat generating parts 12 and 14 and the bus bar 18, and a heat conductive member 24 placed on the placement surface 22 of the case 20, thermally contacted with the case 20 and the bus bar 18, and held between them, and the case 20 has a displacement regulating portion 118 that engages with the heat conductive member 24 to regulate displacement of the heat conductive member 24.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a circuit component including a heat-generating component.

Background Art

[0002] Conventionally, vehicles have been equipped with circuit components including heat-generating components such as relays. For example, Patent Document 1 discloses a circuit component 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 / second bus bars are housed in a case. In such a circuit component, in order to dissipate the heat generated by the relay, which is a heat-generating component, to the outside, a structure is adopted in which the bus bar connected to the relay is press-fitted to the case via a sheet-like heat-conductive member to transfer the heat of the relay to the case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the structure of Patent Document 1, the heat-conductive member disposed via an adhesive or the like in a predetermined arrangement region of the case is merely held in the predetermined arrangement region by being sandwiched between one case (equipment cover) and the other case (battery case). Therefore, when an excessive impact or the like is applied, or when relative displacement occurs between the cases due to the difference in the linear expansion coefficients of one case and the other case, distortion occurs at the interface between the heat-conductive member and the case, and there is a risk that a gap is generated between them and the heat transfer efficiency is reduced.

[0005] Therefore, a circuit component is disclosed that can reduce the stress generated at the interface between the heat-conductive member and the case.

Means for Solving the Problems

[0006] The circuit configuration of the present disclosure comprises a heat-generating component, a busbar connected to a connection portion of the heat-generating component, a case housing the heat-generating component and the busbar, and a heat-conducting member placed on the mounting surface of the case and thermally contacting and sandwiching the case and the busbar, wherein the case has a displacement restricting portion that engages with the heat-conducting member to restrict the displacement of the heat-conducting member. [Effects of the Invention]

[0007] According to this disclosure, a circuit configuration can be provided that can reduce the stress generated at the interface between the heat conductive member and the case. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing a circuit configuration according to Embodiment 1. [Figure 2] Figure 2 is a plan view of the circuit configuration shown in Figure 1. [Figure 3] Figure 3 is a longitudinal cross-sectional view showing an enlarged view of the III-III section in Figure 2. [Figure 4] Figure 4 is an exploded perspective view of the circuit configuration shown in Figure 1. [Figure 5] Figure 5 is a perspective view from the bottom side of the upper case that constitutes the circuit configuration shown in Figure 1. [Figure 6] Figure 6 is a perspective view of the lower case that constitutes the circuit configuration shown in Figure 1. [Figure 7] Figure 7 is a vertical cross-sectional view showing a circuit configuration according to Embodiment 2, and corresponds to Figure 3. [Figure 8] Figure 8 is a perspective view from the bottom side of the upper case that constitutes the circuit configuration shown in Figure 7. [Figure 9] Figure 9 is a perspective view of the lower case that constitutes the circuit configuration shown in Figure 7. [Figure 10]Figure 10 is a vertical cross-sectional view showing the circuit configuration according to Embodiment 3, and is a diagram showing the cross-section corresponding to the XX cross-sectional line in Figure 2. [Figure 11] Figure 11 is a perspective view from the bottom side of the upper case that constitutes the circuit configuration shown in Figure 10. [Figure 12] Figure 12 is a perspective view of the lower case that constitutes the circuit configuration shown in Figure 10. [Modes for carrying out the invention]

[0009] <Description of Embodiments in this Disclosure> First, embodiments of this disclosure will be listed and described. The circuit configuration of the present disclosure comprises a heat-generating component, a busbar connected to a connection portion of the heat-generating component, a case housing the heat-generating component and the busbar, and a heat-conducting member placed on the mounting surface of the case and thermally contacting and sandwiching the case and the busbar, wherein the case has a displacement restricting portion that engages with the heat-conducting member to restrict the displacement of the heat-conducting member.

[0010] According to the circuit configuration of this disclosure, the case housing a heat-generating component and a busbar connected to the connection portion of the heat-generating component has a displacement restricting portion that engages with a heat-conducting member that is thermally in contact with the case and the busbar and sandwiched between them. The displacement restricting portion can engage with the heat-conducting member and restrict the displacement of the heat-conducting member. Therefore, the displacement of the heat-conducting member relative to the case can be advantageously suppressed or prevented, and the stress generated at the interface between the case and the heat-conducting member can be advantageously reduced or eliminated. As a result, the risk of gaps occurring at the interface between the case and the heat-conducting member can be reduced, and the desired heat conduction performance of the circuit configuration transmitted from the connection portion of the heat-generating component to the case via the busbar and the heat-conducting member can be stably maintained. Note that the displacement of the heat-conducting member relative to the case only needs to be suppressed or prevented in at least one direction in the front-to-back, left-to-right, and up-and-down directions as described in the embodiments below.

[0011] Furthermore, the busbar connected to the connection point of the heat-generating component may constitute an electrical circuit, or it may not be electrically connected to any other component and may simply be used as a heat-dissipating metal.

[0012] Preferably, the displacement restricting portion has a protrusion that protrudes from the mounting surface of the case, the heat conducting member has a through hole through which the protrusion is inserted, and the bus bar has a through hole that overlaps the through hole and through which the protrusion is inserted. Since the protrusion that protrudes from the mounting surface of the case is inserted into the through hole of the heat conducting member, the stress generated at the interface between the case and the heat conducting member can be advantageously reduced. Moreover, since the same protrusion is also inserted into the through hole provided in the bus bar that overlaps the heat conducting member, even if, for example, the heat conducting member and the bus bar are held in one case and the other case, respectively, with different coefficients of linear expansion, the transmission of displacement force applied to the heat conducting member via the bus bar can also be suppressed, and the stress generated at the interface between the case and the heat conducting member can be advantageously reduced.

[0013] The case includes a lower case having the placement surface, and an upper case that is assembled by sandwiching the heat conduction member and the bus bar between the lower case. The upper case has a locked portion, and the protruding portion preferably includes a locking portion provided on the lower case and locked and fitted to the locked portion. Since the case has a lower case having a placement surface and an upper case that is assembled by sandwiching a heat conduction member and a bus bar between the lower case, and the protruding portion is configured by using a locking portion that realizes the locking fit between the lower case and the upper case, the protruding portion can be provided efficiently. Moreover, since the locking portion that constitutes the protruding portion is provided on the placement surface on which the heat conduction member is placed, the fitting force between the lower case and the upper case can be directly exerted on the overlapping portion of the heat conduction member and the bus bar, and the displacement of the heat conduction member with respect to the case can be more advantageously suppressed. As a result, even when the linear expansion coefficients of the lower case and the upper case are different, the relative displacement between the two cases in the vicinity of the heat conduction member can be more advantageously suppressed, and the stress generated at the interface between the case and the heat conduction member can be advantageously reduced.

[0014] Note that by adjusting the locking allowance between the locking portion and the locked portion, the pressing force of the heat conduction member against the case due to the locking fit between the upper case and the lower case can be adjusted. Therefore, by appropriately adjusting the locking allowance, the pressing force can be adjusted according to the material and elastic characteristics of the heat conduction member.

[0015] The upper case 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 case is positioned by the through hole of the bus bar, the through hole of the heat conduction member, and the locking portion inserted and arranged in the through hole and the through hole. This is preferable. By providing a positioning rib for the bus bar on the upper case, the locked portion of the upper case can be positioned by the through hole of the bus bar, the through hole of the heat conduction member, and the locking portion of the lower case inserted and arranged therein, and the assembly workability can be improved.

[0016] The lower case and the upper case each have a locking portion and a guide portion and a guided portion arranged on the outer peripheral side of the locked portion. When the upper case is assembled to the lower case, the guided portion is guided in advance by the guide portion, so that the locked portion of the upper case is positioned at the locking portion of the lower case, which is preferable. Since the lower case and the upper case are guided by the guide portion and the guided portion in advance on the outer peripheral side of the locking portion and the locked portion, and the locking portion and the locked portion are positioned, it is possible to further improve the workability of assembling the lower case and the upper case.

[0017] The case has a lower case having the placement surface, and an upper case assembled by sandwiching the heat conduction member and the bus bar between the lower case. The upper case has a press-fitting hole, and the protruding portion preferably includes a press-fitting protrusion provided on the lower case and press-fitted into the press-fitting hole. Since the case has a lower case having a placement surface and an upper case assembled by sandwiching a heat conduction member and a bus bar between the lower case, and the protruding portion is configured by using a press-fitting protrusion for realizing the assembly by press-fitting the lower case and the upper case, the protruding portion can be provided efficiently. Moreover, since the press-fitting protrusion constituting the protruding portion is provided on the placement surface on which the heat conduction member is placed, the assembling force of the lower case and the upper case 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 with respect to the case can be more advantageously suppressed.

[0018] Preferably, the displacement restricting portion has an elastic locking piece protruding from the periphery of the mounting surface of the case, the elastic locking piece has an elastically deformable flexible piece on the outer circumference side of the heat conductive member and a locking claw portion provided at the protruding end of the flexible piece, the locking claw portion engages with the edge of the busbar superimposed on the heat conductive member. By providing an elastic locking piece protruding from the periphery of the mounting surface and engaging the locking claw of the elastic locking piece with the edge of the busbar superimposed on the heat conductive member, the displacement of the heat conductive member relative to the case can be suppressed. As a result, the displacement of the heat conductive member relative to the mounting surface can be suppressed more advantageously, and the stress generated at the interface between the heat conductive member and the case can be reduced even more advantageously. Moreover, since there is no need to provide holes in the busbar, the conductivity resistance of the busbar can be advantageously maintained when the busbar is used as a conductive member.

[0019] Preferably, the upper case has a pressing portion that brings the busbar into contact with the heat conduction member, and the locking portion is provided on the pressing portion. The upper case is provided with a pressing portion that brings the busbar into contact with the heat conduction member, and the locking portion is provided on the pressing portion. This allows the busbar to be pressed against the heat conduction member by utilizing the fastening force of the locking structure between the upper case and the lower case, which can contribute to both the maintenance of heat conduction efficiency and the displacement prevention performance of the heat conduction member relative to the case.

[0020] <Details of the embodiments of this disclosure> Specific examples of the circuit configurations of this disclosure will be described below with reference to the drawings. However, this disclosure is not limited to these examples, and all modifications are intended to be included in the meaning and scope equivalent to the claims as indicated by the claims.

[0021] <Embodiment 1> Hereinafter, Embodiment 1 of this disclosure will be described with reference to Figures 1 to 6. The circuit configuration 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 a motor. The circuit configuration 10 can be positioned in any orientation, but in the following description, "up" refers to the top in Figure 3, "down" refers to the bottom in Figure 3, "front" refers to the bottom in Figure 2, "rear" refers to the top in Figure 2, "left" refers to the left in Figure 2, and "right" refers to the right in Figure 2. In addition, for multiple identical components, reference numerals may be assigned to only some of the components, while the reference numerals for other components may be omitted.

[0022] <Circuit construct 10> The circuit configuration 10 includes a relay 12 and a fuse 14 as heat-generating components that generate heat when energized, a busbar 18 connected to a connection portion 16 of the heat-generating components (relay 12 and fuse 14), a case 20 that houses the heat-generating components (relay 12 and fuse 14) and the busbar 18, and a heat-conducting sheet 24 (first to third heat-conducting sheets 24a to 24c, described later) which is placed on the mounting surface 22 of the case 20 (first to third mounting surfaces 22a to 22c, described later) and is thermally in contact with the case 20 and the busbar 18, sandwiched between them.

[0023] <Heat-generating components (relay 12 and fuse 14)> The relay 12 comprises a relay body 26 which is a hollow rectangular parallelepiped. 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, spaced apart from each other in the left-right direction. An insulating plate 28 protruding forward is provided between the first connection part 16a and the second connection part 16b. The relay body 26 is also provided with a plurality of legs 30 that protrude outward in the left-right direction. In Embodiment 1, bolt insertion holes are formed in these legs 30 that penetrate in the vertical direction, and the relay 12 is fixed to the upper case 58, which will be described later, that constitutes the case 20 by bolts inserted through these bolt insertion holes.

[0024] The fuse 14 comprises a fuse body 32 which is roughly rectangular in shape. The fuse body 32 is provided with metal connecting parts 16, 16 (third connecting part 16c and fourth connecting part 16d) that protrude on both the left and right sides. Bolt insertion holes 34 that penetrate vertically are formed in these third and fourth connecting parts 16c and 16d, and the fuse 14 is fixed to the upper case 58, which will be described later, that constitutes the case 20 by bolts 36 inserted through each of these bolt insertion holes 34.

[0025] <Bus Bar 18> The busbars 18 are formed by bending a metal sheet into a predetermined shape by press working or the like. The material of the busbars 18 is not limited, but copper, copper alloys, aluminum, aluminum alloys, etc., are preferably used. As shown in Figure 4, in Embodiment 1, three busbars 18 are provided spaced apart from each other in the left-right direction, and from left to right they are the first busbar 18a, the second busbar 18b, and the third busbar 18c. In Figures 5 and 6, the first to third busbars 18a, 18b, and 18c, fixed to the upper case 58 and lower case 60 described later, are shown by dashed lines, respectively.

[0026] The first busbar 18a extends horizontally as a whole. At its right end, the first busbar 18a has a roughly rectangular relay connection section 38 (first relay connection section 38a) that extends vertically. From the lower end of the first relay connection section 38a, a roughly rectangular heat transfer section 40 (first heat transfer section 40a) extends rearward in a horizontal direction (perpendicular to the vertical direction). The first busbar 18a also has a roughly rectangular left external connection section 42 that extends horizontally at its left end. The left external connection section 42 is located above the first heat transfer section 40a, and the left external connection section 42 and the first heat transfer section 40a are connected by a crank-shaped bend in the middle of the left-right direction.

[0027] The first relay connection portion 38a has a bolt insertion hole 44 that penetrates in the thickness direction (front-to-back direction). In Embodiment 1, the bolt insertion hole 44 is an elongated oval shape that is longer in the vertical direction. This allows the vertical position of the first busbar 18a relative to the relay 12 to be adjusted when bolting the relay 12 and the first busbar 18a, which will be described later. As a result, when assembling the circuit component 10, the first heat transfer portion 40a can be made to contact the lower case 60, which will be described later, more reliably via the heat conductive sheet 24 (first heat conductive sheet 24a). In addition, the left external connection portion 42 has a bolt insertion hole 46 that penetrates in the thickness direction (vertical direction).

[0028] The second busbar 18b extends horizontally as a whole. A roughly rectangular relay connection section 38 (second relay connection section 38b) that extends vertically is provided at the left end of the second busbar 18b, and a bolt insertion hole 44 that is elongated vertically is formed in the second relay connection section 38b. A roughly rectangular heat transfer section 40 (second heat transfer section 40b) that extends horizontally is connected to the lower end of the second relay connection section 38b. The second heat transfer section 40b extends rearward from the lower end of the second relay connection section 38b and also extends horizontally from the second relay connection section 38b at the left end of the second busbar 18b to the right portion of the second busbar 18b. In addition, the second busbar 18b has a roughly rectangular fuse connection section 48 that extends horizontally at its right end. The fuse connection portion 48 is located above the second heat transfer portion 40b, and the fuse connection portion 48 and the second heat transfer portion 40b are connected by a portion that extends vertically.

[0029] In Embodiment 1, a circular through-hole 50 is provided in the thickness direction (vertical direction) of the second heat transfer section 40b, which extends in the left-right direction, approximately in the center in the front-rear direction. In particular, in Embodiment 1, a pair of through-holes 50, 50 are provided, and these two pairs of through-holes 50, 50 are spaced apart from each other in the left-right direction. As shown in Figure 3, the inner diameter of each of these through-holes 50 is approximately equal to or slightly smaller than the maximum outer diameter of the portion where each fitting claw 106 is formed at the upper end of each protrusion 100 of the lower case 60, which will be described later, and is approximately equal to or slightly larger than the outer diameter of the portion where each fitting claw 106 is not formed on each protrusion 100.

[0030] As a result, as will be described later, when inserting each projection 100 into each through hole 50, each fitting claw 106 (each elastic piece 104) elastically deforms radially inward, allowing each projection 100 to be inserted into each through hole 50. Furthermore, after inserting each projection 100 into each through hole 50, each fitting claw 106 (each elastic piece 104) elastically returns to its original shape, preventing each projection 100 from coming out of each through hole 50. In addition, the fuse connection portion 48 has a bolt insertion hole 52 that penetrates in the thickness direction (vertical direction). That is, in the second bus bar 18b, each through hole 50 is provided in relatively close proximity to each bolt insertion hole 44, 52.

[0031] The third busbar 18c extends horizontally as a whole. A roughly rectangular fuse connector 48 is provided at the left end of the third busbar 18c, and a bolt insertion hole 52 is formed in the fuse connector 48 that penetrates in the thickness direction (vertical direction). A roughly rectangular right external connector 54 is provided at the right end of the third busbar 18c, and a bolt insertion hole 56 is formed in the right external connector 54 that penetrates in the thickness direction (vertical direction).

[0032] In the third busbar 18c, a roughly rectangular heat transfer section 40 (third heat transfer section 40c) is provided in the middle portion in the left-right direction. That is, the fuse connection section 48 located at the left end of the third busbar 18c and the right external connection section 54 located at the right end are connected via the third heat transfer section 40c. This third heat transfer section 40c is located below the fuse connection section 48 and the right external connection section 54, and the third heat transfer section 40c is connected to the fuse connection section 48 and the right external connection section 54 by portions that extend in the vertical direction.

[0033] <Case 20> The case 20 is box-shaped overall and is formed of, for example, synthetic resin. As shown in Figure 2, in Embodiment 1, the case 20 is substantially rectangular in shape, extending in the left-right direction in a plan view. The case 20 is composed of an upper case 58 located above and a lower case 60 located below, and these upper case 58 and lower case 60 can be assembled and separated in the vertical direction. The material of the synthetic resin constituting the upper case 58 and lower case 60 is not limited, but may include fillers such as glass fiber. The material of the upper case 58 and the material of the lower case 60 may be different, and it is particularly preferable that the material of the lower case 60 exhibits good thermal conductivity, and a nylon-based synthetic resin, such as polyamide 6 (PA6), may be used.

[0034] <Upper Case 58> The upper case 58 is generally box-shaped with an opening downwards, and comprises a roughly rectangular upper bottom wall 62 extending in the left-right direction, and an upper circumferential wall 64 projecting downwards from the outer peripheral edge of the upper bottom wall 62. Furthermore, roughly rectangular openings 66a and 66b that penetrate vertically are formed at both left-right ends of the upper bottom wall 62. In addition, in the front portion of the upper circumferential wall 64, notches 68 that penetrate in the thickness direction (front-to-back direction) are provided at positions corresponding to each connection part 16 (first and second connection parts 16a and 16b) of the relay 12 fixed to the upper case 58, and a pair of notches 68, 68 are spaced apart from each other in the left-right direction. As a result of providing these notches 68, bolts 120, which will be described later, can be fastened from the front through each notch 68 to each connection part 16 (first and second connection parts 16a and 16b) of the relay 12 fixed to the upper case 58.

[0035] As shown in Figures 3 and 5, the upper case 58 is provided with a pressing portion 70 that brings the busbar 18 into contact with the heat conductive sheet 24. The pressing portion 70 is generally rectangular in shape and is provided protruding downward from the upper bottom wall 62 within the internal space of the upper case 58. In Embodiment 1, the pressing portion 70 is integrally formed with the upper bottom wall 62 in the middle portion of the upper bottom wall 62 in the left-right direction, with predetermined front-rear and left-right dimensions. In particular, in Embodiment 1, the pressing portion 70 is formed with a front-rear dimension that is slightly larger than the front-rear dimension of the portion in the second heat transfer portion 40b of the second busbar 18b where each through hole 50 is formed.

[0036] Furthermore, the pressing portion 70 has a predetermined vertical dimension, and as will be described later, with the busbar 18 (second busbar 18b) and the heat conductive sheet 24 (second heat conductive sheet 24b) superimposed on the lower end of the pressing portion 70, the pressing portion 70 is superimposed on the bottom wall 90 of the lower case 60, which will be described later, via the busbar 18 (second busbar 18b) and the heat conductive sheet 24 (second heat conductive sheet 24b). In other words, the upper case 58 and the lower case 60 are assembled together with the heat conductive sheet 24 (second heat conductive sheet 24b) and the busbar 18 (second busbar 18b) sandwiched between the pressing portion 70 and the bottom wall 90 in the vertical direction.

[0037] The pressing portion 70 has a plurality of substantially rectangular weight-reducing holes 72 that open downward, and these plurality of weight-reducing holes 72 are arranged in alignment in the front-to-back and left-to-right directions. As a result, when viewed from the bottom of the upper case 58, the pressing portion 70 is formed in a substantially grid pattern. The pressing portion 70 also has a locking portion 74 into which a locking portion 102, described later, provided on the lower case 60, is locked. Specifically, the locking portion 74 is provided at the lower end of a cylindrical portion 76 that protrudes 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 part of the pressing portion 70 in the front-to-back direction, and a pair of cylindrical portions 76, 76 are provided separated from each other in the left-to-right direction. That is, in the upper case 58, a pair of locking portions 74, 74 are provided separated from each other in the left-to-right direction.

[0038] More specifically, at the lower end of each cylindrical portion 76, fitting claws 78 protruding inward are provided on both sides in the front-rear direction, thereby forming a locking portion 74 at the lower end of each cylindrical portion 76. Furthermore, the lower end surfaces of each fitting claw 78 facing each other in the front-rear direction are inclined surfaces 80, and these inclined surfaces 80 are inclined in such a way that the distance between the opposing surfaces in the front-rear direction gradually increases as they are lower.

[0039] Furthermore, positioning ribs 82 for positioning the busbar 18 (second busbar 18b) are provided at both front-rear and rear-facing ends of the pressing portion 70. Each of these positioning ribs 82 is provided projecting downward from both front-rear and rear-facing ends of the pressing portion 70. In Embodiment 1, positioning ribs 82, 82 having predetermined left-right dimensions are provided at both front-rear and rear-facing ends of the pressing portion 70, and at both left-right ends, spaced apart from each other in the left-right direction. The front-rear spacing dimension of the positioning ribs 82, 82 facing each other in the front-rear direction is approximately equal to or slightly larger than the front-rear dimension of the portion in the second heat transfer portion 40b of the second busbar 18b where each through-hole 50 is formed. As a result, when the second busbar 18b is superimposed on the pressing portion 70, the second busbar 18b is positioned between the positioning ribs 82, 82 that are spaced apart in the front-rear direction.

[0040] Furthermore, the inner surface of the upper circumferential wall 64 of the upper case 58 is provided with guided portions 84 that guide the guide portion 110, which will be described later and is provided on the lower case 60, when assembling the upper case 58 and the lower case 60. In Embodiment 1, a plurality of guided portions 84 are provided on both the front-rear and rear-facing sides of the inner surface of the upper circumferential wall 64, spaced apart from each other in the left-right direction. That is, in the upper case 58, each guided portion 84 is provided on the outer circumference side of each locked portion 74.

[0041] Specifically, each guided portion 84 is equipped with a guided portion body 86 which is shaped like a roughly rectangular parallelepiped and is formed with predetermined left-right and front-back dimensions. Each of these guided portion bodies 86 extends in the vertical direction, which is the assembly direction between the upper case 58 and the lower case 60, and each guided portion body 86 protrudes downward from the upper bottom wall 62. The vertical dimension of each guided portion body 86 is approximately equal to the vertical 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 approximately the same position in the vertical direction.

[0042] Each of these guided body parts 86 is located a predetermined distance inward from the upper circumferential wall 64 (inward in the front-rear direction in Embodiment 1), and the upper circumferential wall 64 and each guided body part 86 are connected by connecting parts 88. Each connecting part 88 extends vertically with a vertical dimension smaller than that of each guided body part 86. In addition, each connecting part 88 has a horizontal dimension smaller than that of each guided body part 86, and each connecting part 88 connects the upper circumferential wall 64 and each guided body part 86 at the horizontal central portion of each guided body part 86.

[0043] <Lower Case 60> As shown in Figure 6, the lower case 60 is a roughly box-shaped structure that opens upwards overall, and includes a roughly rectangular bottom wall 90 extending in the left-right direction, and a lower peripheral wall 92 projecting upwards from the outer peripheral edge of the bottom wall 90. Furthermore, roughly rectangular block-shaped support parts 94a and 94b are provided at both left and right ends of the lower case 60 to support the left external connection part 42 of the first busbar 18a and the right external connection part 54 of the third busbar 18c, respectively, when assembling the circuit configuration 10. As a result, when assembling the circuit configuration 10, the left and right external connection parts 42 and 54 supported on both support parts 94a and 94b are exposed upwards through the two openings 66a and 66b of the upper case 58.

[0044] Nuts (not shown) are provided in a nearly embedded state in these support parts 94a and 94b. The left and right external connection parts 42 and 54 and terminals (not shown) provided at the ends of the external wires are superimposed on the two support parts 94a and 94b, and bolts are inserted through the two bolt insertion holes 46 and 56 and fastened to the nuts, thereby creating electrical contact between the first and third busbars 18a and 18c and the external wires.

[0045] Furthermore, on the upper surface of the bottom wall 90, a substantially rectangular upper receiving recess 96 that opens upward is provided at a position corresponding to the heat transfer section 40 of the bus bar 18. In Embodiment 1, since there are three bus bars (first to third bus bars 18a to 18c), the first to third upper receiving recesses 96a to 96c are provided on the upper surface of the bottom wall 90 at positions corresponding to the first to third heat transfer sections 40a to 40c of the first to third bus bars 18a to 18c, spaced apart from each other in the left-right direction. As will be described later, since the heat conductive sheets 24 (first to third heat conductive sheets 24a to 24c) are 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 are designated as mounting surfaces 22 (first to third mounting surfaces 22a to 22c). Note that these first to third upper receiving recesses 96a to 96c are not essential, and the heat conductive members (for example, the first to third heat conductive sheets 24a to 24c) may be placed on the upper surface of the bottom wall. In this case, the surface on which they are placed may be the upper surface of the bottom wall.

[0046] Furthermore, as shown in Figure 3, on the lower surface of the bottom wall 90, a substantially rectangular lower accommodating recess 98 that opens downward is provided at positions corresponding to the first to third upper accommodating recesses 96a to 96c. In Embodiment 1, three lower accommodating recesses 98 are provided on the lower surface of the bottom wall 90, corresponding to the first to third upper accommodating recesses 96a to 96c, spaced apart from each other in the left-right direction. However, in Figure 3, only the lower accommodating recess 98 corresponding to the second upper accommodating recess 96b is shown. As these first to third upper accommodating recesses 96a to 96c and each lower accommodating recess 98 are provided on the bottom wall 90, the bottom wall 90 is thinner at the formation positions of the first to third upper accommodating recesses 96a to 96c and each lower accommodating recess 98 compared to other parts.

[0047] Each of these lower housing recesses 98 accommodates and fixes a heat conductive member (heat conductive sheet), not shown, similar to the first to third heat conductive sheets 24a to 24c placed in the first to third upper housing recesses 96a to 96c. The bottom wall 90 then thermally contacts a heat sink, not shown, such as a vehicle panel or battery pack housing, via the heat conductive member (heat conductive sheet) housed in each lower housing recess 98, so that the heat generated in the relay 12 and fuse 14 is dissipated through the heat sink.

[0048] In this configuration, the mounting surface 22 of the lower case 60 is provided with a projection 100 that protrudes upward. In Embodiment 1, a pair of projections 100, 100 are provided in the left-right intermediate portion of the front-rear central portion of the lower case 60, projecting upward from the second mounting surface 22b, and these two projections 100, 100 are spaced apart from each other in the left-right direction. In particular, in Embodiment 1, each projection 100 includes a locking portion 102 that locks into each locking portion 74 of the upper case 58.

[0049] Specifically, each protrusion 100 is substantially cylindrical in shape and can be fitted into each cylindrical portion 76 of the upper case 58. Multiple spaced notches are provided in the circumferential wall of the cylinder. As a result, elastic pieces 104 that can be elastically deformed in the radial direction of each substantially cylindrical protrusion 100 are provided on both the front-rear and rear-facing sides of each protrusion 100. A fitting claw 106 that protrudes outward in the front-rear direction is provided at the upper end 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.

[0050] In other words, in Embodiment 1, elastic pieces 104 having each fitting claw 106 are provided on each protruding portion 100, facing each other in the front-rear direction. Furthermore, the upper end surface of each fitting claw 106 is an inclined surface 108, and each inclined surface 108 is inclined in a direction such that the outward protrusion dimension of each fitting claw 106 in the front-rear direction gradually increases as it goes downwards.

[0051] Furthermore, guide portions 110 are provided on the lower peripheral wall 92 of the lower case 60 at positions corresponding to the guided portion 84 of the upper case 58. In other words, in Embodiment 1, multiple guide portions 110 are provided on both the front-rear and rear-facing sides of the lower peripheral wall 92, spaced apart from each other in the left-right direction. That is, in the lower case 60, each guide portion 110 is provided on the outer periphery side of each lock portion 102.

[0052] Specifically, as shown in Figures 4 and 6, each guide section 110 is provided with a pair of guide wall sections 112, 112 that project inward (inward in the front-rear direction in Embodiment 1) from the inner surface of the lower circumferential wall 92. Each of these guide wall sections 112 extends in the vertical direction, and in each guide section 110, the pair of guide wall sections 112, 112 are separated from each other by a left-right dimension that is approximately equal to or slightly larger than the left-right dimension of each guided section body 86 in the upper case 58. In addition, in each guide section 110, a notched window 114 is provided in the left-right central portion between the pair of guide wall sections 112, 112, which opens upward in the lower circumferential wall 92 and penetrates in the front-rear direction. Each notched window 114 is formed with a vertical dimension that does not reach the entire vertical length of the lower circumferential wall 92. The widthwise dimension (left-right dimension in Embodiment 1) of each notched window 114 is approximately equal to or slightly larger than the left-right dimension of each connecting portion 88 in the upper case 58.

[0053] Because each guided portion 84 in the upper case 58 and each guide portion 110 in the lower case 60 are shaped as described above, when the upper case 58 and the lower case 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 each notched window 114. As a result, when the upper case 58 and the lower case 60 are assembled, the guide portion 110 is guided vertically relative to the guided portion 84.

[0054] In particular, by inserting each guided part body 86 into a pair of guide wall parts 112, 112 in a substantially press-fit state, or by inserting each connecting part 88 into each notched window 114 in a substantially press-fit state, it becomes possible to assemble the upper case 58 and the lower case 60 in a state of being fixed to each other. That is, the fixing mechanism between the upper case 58 and the lower case 60 may be formed by these guide parts 110 and each guided part 84. Note that the fixing mechanism between the upper case 58 and the lower case 60 may be provided separately from the fixing mechanism by each guide part 110 and each guided part 84, or in addition to the fixing mechanism by each guide part 110 and each guided part 84. For example, a locking fitting by each lock part 102 and each locked part 74 may be used as the fixing mechanism between the upper case 58 and the lower case 60.

[0055] <Thermal conductive material (thermal conductive sheet 24)> During the assembly of the circuit assembly 10, a heat conductive sheet 24, which is a sheet-like heat conductive member, is provided between the heat transfer section 40 of the bus bar 18 and the bottom wall 90 of the lower case 60. In Embodiment 1, the first to third heat conductive sheets 24a to 24c are housed in the first to third upper receiving recesses 96a to 96c of the bottom wall 90 of the lower case 60 at positions corresponding to the first to third heat transfer sections 40a to 40c of the first to third bus bars 18a to 18c. As a result, during the assembly of the circuit assembly 10, the first to third heat transfer sections 40a to 40c and the bottom wall 90 are in thermal contact via the first to third heat conductive sheets 24a to 24c. The first to third heat conductive sheets 24a to 24c may be fixed to the lower surfaces of the first to third heat transfer sections 40a to 40c, or to the first to third mounting surfaces 22a to 22c of the first to third upper housing recesses 96a to 96c, or they may not be fixed to any of these. Furthermore, as described above, heat conductive members (not shown) are housed in each lower housing recess 98 of the bottom wall 90 of the lower case 60 and are sandwiched between the bottom wall 90 and the heat sink in the vertical direction.

[0056] The first to third thermal conductive sheets 24a to 24c are flattened sheets in the vertical direction and are made of a synthetic resin with a higher thermal conductivity than air. Specifically, silicone-based resins, non-silicone acrylic resins, ceramic resins, etc., can be used. More specifically, thermally conductive silicone rubber can be used. The first to third thermal conductive sheets 24a to 24c are flexible and elastic, and can be elastically deformed so that their thickness changes in response to a force applied in the vertical direction. In Embodiment 1, sheet-shaped thermal conductive members (for example, the first to third thermal conductive sheets 24a to 24c) are used as thermal conductive members provided on both the upper and lower surfaces of the bottom wall 90 of the lower case 60, but each thermal conductive member is not limited to this embodiment and any thermal conductive member of any shape can be used. As each thermal conductive member, for example, a heat dissipation gap filler or thermal conductive grease made of a silicone-based resin may be used.

[0057] The materials used for the synthetic resins constituting the case 20 (upper case 58 and lower case 60) and the synthetic resins constituting the heat conductive members (first to third heat conductive sheets 24a to 24c) are not limited. However, for example, if the lower case 60 is made of a nylon-based synthetic resin (e.g., PA6) and the first to third heat conductive sheets 24a to 24c are made of a silicone-based synthetic resin, delamination is likely to occur between the lower case 60 and the first to third heat conductive sheets 24a to 24c. Therefore, by using these materials, the effects of this disclosure can be more effectively realized.

[0058] In particular, it is preferable that the first to third heat conductive sheets 24a to 24c are compressed and sandwiched between the first to third heat transfer sections 40a to 40c and the bottom wall 90 of the lower case 60 in the vertical direction. By being compressed, the first to third heat conductive sheets 24a to 24c can make contact with the first to third heat transfer sections 40a to 40c and the bottom wall 90 of the lower case 60 with a high degree of adhesion. As a result, the first to third heat conductive sheets 24a to 24c can efficiently transfer heat from the first to third heat transfer sections 40a to 40c to the lower case 60. Similarly, it is preferable that each heat conductive member provided on the lower surface of the bottom wall 90 of the lower case 60 is compressed and sandwiched between the bottom wall 90 and the heat sink in the vertical direction. As a result, each heat conductive member can make contact with the bottom wall 90 and the heat sink with a high degree of adhesion, and can efficiently transfer heat from the lower case 60 to the heat sink.

[0059] In this configuration, the thermal conductive sheet 24 is provided with through holes 116 through which each of the protrusions 100 provided on the lower case 60 is inserted. In Embodiment 1, since a pair of protrusions 100, 100 are provided on the second mounting surface 22b of the lower case 60, a pair of through holes 116, 116 are provided in the second thermal conductive sheet 24b placed on the second mounting surface 22b. These through holes 116 are provided in the second thermal conductive sheet 24b, approximately in the center in the front-to-back direction, and spaced apart from each other in the left-to-right direction.

[0060] The inner diameter of each through-hole 116 is approximately equal to the inner diameter of each through-hole 50 provided in the second busbar 18b, as shown in Figure 3. That is, the inner diameter of each through-hole 116 is approximately equal to or slightly smaller than the maximum outer diameter of the portion where each fitting claw 106 is formed at the upper end of each protrusion 100 of the lower case 60, and approximately equal to or slightly larger than the outer diameter of the portion where each fitting claw 106 is not formed on each protrusion 100.

[0061] As a result, when assembling the circuit assembly 10, each protrusion 100 in the lower case 60 is inserted into and engaged with each through-hole 116 in the second heat conductive sheet 24b, thereby restricting the displacement of the second heat conductive sheet 24b relative to the lower case 60. Therefore, in Embodiment 1, the displacement restricting part 118, which is provided on the case 20 and engages with the heat conductive sheet 24 to restrict the displacement of the heat conductive sheet 24, is configured to include each protrusion 100.

[0062] <Assembly process of circuit component 10> Next, a specific example of the assembly process for the circuit component 10 will be described. Note that the assembly process for the circuit component 10 is not limited to the following description.

[0063] First, prepare the upper case 58, lower case 60, relay 12, fuse 14, first to third busbars 18a to 18c, bolts 36, first to third thermal conductive sheets 24a to 24c, etc. Then, place the relay 12 on the upper bottom wall 62 of the inverted upper case 58, and bolt the relay 12 to the upper case 58 using bolts inserted through each leg portion 30.

[0064] Subsequently, the first and second busbars 18a and 18b are placed on top of the relay 12, aligning the first and second connection portions 16a and 16b of the relay 12 with the bolt insertion holes 44 of the first and second busbars 18a and 18b in the front-rear direction. When the second busbar 18b is placed on the relay 12, the second heat transfer portion 40b of the second busbar 18b is superimposed on the pressing portion 70 of the upper case 58 from above, and the positioning ribs 82 provided on the pressing portion 70 position the second busbar 18b in the front-rear direction relative to the upper case 58.

[0065] Next, bolts 120 are inserted from the front into the first and second connecting parts 16a and 16b and the bolt insertion holes 44 to fasten them. This fixes the relay 12 to the first and second busbars 18a and 18b. With the second busbar 18b fixed to the relay 12 (upper case 58) in this way, the inner holes of each cylindrical part 76 in the pressing part 70 and the through holes 50 in the second busbar 18b are aligned with each other and communicate in the vertical direction.

[0066] Next, the third bus bar 18c is placed on the upper bottom wall 62 of the upper case 58, and the fuse 14 is placed on the second and third bus bars 18b and 18c so that the third and fourth connection parts 16c and 16d of the fuse 14 overlap with the fuse connection parts 48 of the second and third bus bars 18b and 18c. This aligns the bolt insertion holes 52 of each fuse connection part 48 with the bolt insertion holes 34 of the third and fourth connection parts 16c and 16d. Then, bolts 36 are inserted through the bolt insertion holes 34 and 52 to fasten them. In this way, the fuse 14 and the third bus bar 18c are fixed to the upper case 58 in addition to the relay 12 and the first and second bus bars 18a and 18b.

[0067] The upper case 58 is inverted upside down and positioned opposite the lower case 60 from above. The mounting surfaces 22 (first to third mounting surfaces 22a to 22c), which are the bottom surfaces of the first to third upper receiving recesses 96a to 96c of the lower case 60, are pre-attached with heat conductive sheets 24 (first to third heat conductive sheets 24a to 24c) via adhesive or the like. As a result, each protrusion 100 on the lower case 60 is inserted into and engaged with each through-hole 116 in the second heat conductive sheet 24b. Then, each guided portion 84 on the upper case 58 is inserted into each guide portion 110 on the lower case 60. As a result, the inner holes and through holes 50 of each cylindrical portion 76 that are in communication with each other on the upper case 58 side, and the protruding portions 100 that penetrate each through hole 116 of the second heat conductive sheet 24b on the lower case 60 side, are positioned to face each other in the vertical direction. That is, the locking portions 74 provided on each cylindrical portion 76 and the locking portions 102 provided on each protruding portion 100 are positioned to face each other in the vertical direction.

[0068] Then, each guide portion 110 is guided along each guided portion 84, bringing the upper case 58 and the lower case 60 closer together 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 come into contact in the vertical direction, and each elastic piece 104 on each locking portion 102 elastically deforms radially inward. This allows each protruding portion 100 to be inserted into each cylindrical portion 76, each through hole 50, and each through hole 116. Then, each fitting claw 106 on each locking portion 102 overcomes each fitting claw 78 on each locked portion 74, causing each elastic piece 104 to elastically return to its original shape and lock each fitting claw 106 into each fitting claw 78. As a result, each guided portion 84 is inserted into each guide portion 110 in a substantially press-fit state, and each locking portion 102 and each locked portion 74 are locked together, thereby fixing the upper case 58 and the lower case 60 to each other. As a result, the circuit assembly 10 is completed. In the completed state of the circuit assembly 10, the second bus bar 18b and the second thermal conductive sheet 24b are stacked in the vertical direction, and each protrusion 100 is inserted through each through hole 50 and each through hole 116 that are stacked on top of each other.

[0069] The circuit configuration 10 assembled in this manner is superimposed on a heat sink such as a vehicle body panel or battery pack housing (not shown) and fixed with bolts or the like. As a result, for example, a heat conductive member (not shown) provided on the underside of the bottom wall 90 of the lower case 60 can be compressed vertically between the lower case 60 and the heat sink. Then, the heat generated when current flows through the relay 12 and fuse 14 is dissipated from the heat sink (not shown) via the first to third heat transfer sections 40a to 40c of the first to third busbars 18a to 18c which are superimposed vertically, the first to third heat conductive sheets 24a to 24c, the bottom wall 90 of the lower case 60, and a heat conductive member (not shown) provided on the underside of the bottom wall 90.

[0070] In the circuit configuration 10 of Embodiment 1, the lower case 60 constituting the case 20 is provided with a displacement restricting portion 118 that engages with the second heat conductive sheet 24b and restricts the displacement of the second heat conductive sheet 24b. This prevents gaps from forming between the lower case 60 and the second heat conductive sheet 24b, even when the case 20 is exposed to a high-temperature environment and expands or contracts, or when a large impact is applied from the outside, thereby ensuring that the desired heat dissipation effect is stably achieved. In particular, when the lower case 60 is made of a material with good thermal conductivity relative to the upper case 58, the lower case 60 and the upper case 58 are prone to relative displacement due to the difference in their coefficients of linear expansion in high-temperature environments. Even in this case, the displacement restricting portion 118 advantageously reduces the stress generated at the interface between the lower case 60 and the second heat conductive sheet 24b, thus maintaining the desired heat dissipation effect of the circuit configuration 10.

[0071] More specifically, in Embodiment 1, the displacement restricting portion 118 is configured to include each protrusion 100 in the lower case 60, and each protrusion 100 (each locking portion 102) and each cylindrical portion 76 (each locked portion 74) in the upper case 58 are locked and fitted together. As a result, relative displacement between the upper case 58 and the lower case 60 is suppressed in any of the front-rear, left-right, and up-down directions. Therefore, the second heat conductive sheet 24b sandwiched between the upper case 58 and the lower case 60 is subjected to suppressed displacement relative to the case 20 (upper case 58 and lower case 60) in any of the front-rear, left-right (i.e., shear direction) and up-down (tensile direction) directions, thereby enabling the desired heat dissipation effect to be achieved.

[0072] The displacement restricting portion 118 has protrusions 100 that project upward from the second mounting surface 22b of the lower case 60, and each protrusion 100 is inserted through each through hole 50 provided in the second busbar 18b and each through hole 116 provided in the second heat conductive sheet 24b. By adopting this structure in which each protrusion 100 is inserted through each through hole 116 in the second heat conductive sheet 24b, the displacement restricting effect of the second heat conductive sheet 24b relative to the lower case 60 can be stably obtained. Furthermore, in Embodiment 1, each through hole 50 (i.e., each locked portion 74 and each locked portion 102) is provided relatively close to the bolt fastening points (bolt insertion holes 44, 52) where external forces are likely to be applied in the second busbar 18b. This prevents the second busbar 18b from deforming to rotate at the bolt fastening points due to impact, differences in the coefficient of linear expansion, etc. As a result, displacement of the second heat conductive sheet 24b, which is sandwiched between the second busbar 18b and the lower case 60, relative to the case 20 is also prevented. The through holes in the busbar (i.e., the locking structure formed by the locked portion and the locking portion) may be provided at two locations away from the axis of rotation of the bolt fastening point (bolt insertion hole) in the busbar, so as to face each other across the axis of rotation. This can more effectively prevent displacement of the busbar in the rotational direction relative to the case.

[0073] In particular, the case 20 is composed of an upper case 58 and a lower case 60, and the upper case 58 and the lower case 60 have locking parts 74 and locking parts 102 that lock into each other. As a result, even when an external force is applied to the upper case 58 and the lower case 60 in a direction that separates them in the vertical direction opposite to the assembly direction, the relative displacement between the second bus bar 18b on the upper case 58 side and the lower case 60 is suppressed, and peeling of the second heat conductive sheet 24b sandwiched between them from the second bus bar 18b and the lower case 60 is prevented.

[0074] The upper case 58 is provided with positioning ribs 82 in the pressing portion 70 for positioning the second busbar 18b. This allows the second busbar 18b, to which the second heat conductive sheet 24b is fixed, to be quickly aligned with the upper case 58 when assembling it to the upper case 58. Furthermore, after assembling the second heat conductive sheet 24b and the second busbar 18b to the upper case 58, misalignment between the inner holes in each cylindrical portion 76, each through hole 50, and each through hole 116 is effectively prevented, thus enabling stable insertion of each protrusion 100 into each cylindrical portion 76, each through hole 50, and each through hole 116.

[0075] In particular, the upper case 58 is provided with guided portions 84, and the lower case 60 is provided with guide portions 110. When assembling the upper case 58 and the lower case 60, the guide portions 110 are inserted into the guided portions 84, and the locking portions 102 and the locked portions 74 are positioned relative to each other in the vertical direction. As a result, while maintaining the inserted state of each guide portion 110 into each guided portion 84, the upper case 58 and the lower case 60 are brought closer to each other, thereby locking each locking portion 102 into each locked portion 74, and thus stable engagement between each locking portion 102 and each locked portion 74 can be achieved.

[0076] The upper case 58 has a pressing portion 70, and the second busbar 18b and the second heat conductive sheet 24b are sandwiched between the pressing portion 70 and the lower case 60. In addition, each locking portion 74 is provided on the pressing portion 70, and engages with each locking portion 102 on the lower case 60. That is, the second busbar 18b and the second heat conductive sheet 24b are sandwiched between the upper case 58 and the lower case 60 in the vertical direction near each locking portion 102 and each locking portion 74 that realize the lock between the upper case 58 and the lower case 60. Therefore, the occurrence of a gap between the second heat conductive sheet 24b and the lower case 60 due to vertical separation displacement between the upper case 58 and the lower case 60 can be effectively prevented.

[0077] <Embodiment 2> Hereinafter, Embodiment 2 of this disclosure will be described with reference to Figures 7 to 9. The circuit component 130 of Embodiment 2 has the same basic structure as the circuit component 10 of Embodiment 1, but the structure of the cylindrical portion 134 in the upper case 132 and the protruding portion 138 in the lower case 136 are different. Therefore, in the following description, the differences from the circuit component 10 in Embodiment 1 will be explained, and detailed explanations of substantially identical members and parts to those in Embodiment 1 will be omitted by denoting them with the same reference numerals as in Embodiment 1 in the figures.

[0078] <Upper Case 132> In the upper case 132 of Embodiment 2, as with the upper case 58 of Embodiment 1, a pressing portion 70 is provided that protrudes downward from the middle portion in the left-right direction of the upper bottom wall 62. Similar to Embodiment 1, a plurality of weight-reducing holes 72 are provided in this pressing portion 70, and a cylindrical portion 134 is provided within the weight-reducing holes 72 in the central portion of the pressing portion 70 in the front-rear direction. In Embodiment 2, a pair of cylindrical portions 134, 134 are provided, and these pair of cylindrical portions 134, 134 are separated from each other in the left-right direction.

[0079] In Embodiment 1, each cylindrical portion 76 was provided with a fitting claw 78 protruding inward to form each locking portion 74. However, in Embodiment 2, each cylindrical portion 134 has a substantially constant inner diameter along its entire length in the vertical direction. As will be described later, each protruding portion 138 of the lower case 136 is press-fitted into the inner hole of each cylindrical portion 134. Therefore, in Embodiment 2, the inner hole of each cylindrical portion 134 constitutes a press-fit hole 140.

[0080] <Lower Case 136> In the lower case 136 of Embodiment 2, similar to the lower case 60 of Embodiment 1, a projection 138 is provided that protrudes upward from the central part of the second mounting surface 22b in the front-rear direction. In Embodiment 2 as well, a pair of projections 138, 138 are provided, and these two projections 138, 138 are separated from each other in the left-right direction.

[0081] In Embodiment 1, each protrusion 100 was provided with an elastic piece 104 and a fitting claw 106 to form a locking portion 102. However, in Embodiment 2, each protrusion 138 has an outer diameter that is substantially constant along its entire length in the vertical direction. The outer diameter of each protrusion 138 is substantially equal to or slightly larger than the inner diameter of each cylindrical portion 134 (each press-fit hole 140) in the upper case 132, so that each protrusion 138 is press-fitted into each press-fit hole 140 when assembling the upper case 132 and the lower case 136. In other words, in Embodiment 2, each protrusion 138 is configured to include a press-fit projection 142.

[0082] Therefore, in Embodiment 2, the upper case 132 and the lower case 136 are fixed together by a press-fit structure of each press-fit projection 142 into each press-fit hole 140 (and, if necessary, a press-fit structure of each guided portion 84 into each guide portion 110). At this time, each protrusion 138 is inserted into and engaged with each through hole 116 in the second heat conductive sheet 24b in advance, thereby restricting the relative displacement between the lower case 136 and the second heat conductive sheet 24b. As a result, in Embodiment 2, a displacement restricting portion 144 is configured that restricts the displacement of the second heat conductive sheet 24b, including each protrusion 138.

[0083] Thus, in the circuit assembly 130 of Embodiment 2, the only difference from the circuit assembly 10 of Embodiment 1 is the fixing structure of the upper case 132 and the lower case 136, and therefore the same effects as the circuit assembly 10 of Embodiment 1 can be achieved. In addition, in Embodiment 2, each press-fit hole 140 is provided in the pressing portion 70, and each press-fit projection 142 in the lower case 136 is press-fitted. As a result, in Embodiment 2 as well, the second busbar 18b and the second heat conductive sheet 24b are sandwiched between the upper case 132 and the lower case 136 in the vertical direction near each press-fit hole 140 and each press-fit projection 142 that fix the upper case 132 and the lower case 136. Therefore, the occurrence of a gap between the second heat conductive sheet 24b and the lower case 136 due to vertical separation displacement between the upper case 132 and the lower case 136 can be effectively prevented.

[0084] <Embodiment 3> Hereinafter, Embodiment 3 of this disclosure will be described with reference to Figures 10 to 12. The circuit component 150 of Embodiment 3 has the same basic structure as the circuit component 10 of Embodiment 1 and the circuit component 130 of Embodiment 2, but the structure of the displacement restricting section 152 is different from that of Embodiments 1 and 2. Therefore, in the following description, the differences from Embodiments 1 and 2 will be explained, and detailed explanations will be omitted for components and parts that are substantially the same as those in Embodiments 1 and 2, by denoting them with the same reference numerals in the figures as in Embodiments 1 and 2. In Embodiment 3, as in Embodiments 1 and 2, three busbars 18 (first to third busbars 18a to 18c) are provided, and the second heat conductive sheet 24b superimposed on the second busbar 18b is divided into two in the left-right direction, with a left second heat conductive sheet 154a and a right second heat conductive sheet 154b provided. In Figures 11 and 12, the first to third busbars 18a to 18c, as well as each thermal conductive sheet 24 (first and third thermal conductive sheets 24a and 24c, and the left and right second thermal conductive sheets 154a and 154b) are shown by dashed lines.

[0085] <Upper Case 156> In the upper case 156 of Embodiment 3, similar to the upper case 58 of Embodiment 1, a pressing portion 70 is provided that protrudes downward from the middle portion of the upper bottom wall 62 in the left-right direction. Furthermore, in Embodiment 3, insertion grooves 158 are provided on both sides of the outer circumferential surface of the pressing portion 70 in the front-rear direction, opening outward in the front-rear direction and extending in the vertical direction. In particular, in Embodiment 3, 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, so a total of four insertion grooves 158 are provided on the pressing portion 70.

[0086] Each insertion groove 158 has a roughly rectangular cross-section and has a predetermined width dimension (left-right dimension) and depth dimension (front-rear dimension). The depth dimension of each insertion groove 158 is larger than the width dimension (front-rear dimension) of each positioning rib 82 provided at both front-rear ends of the pressing section 70, so that the bottom surface of each insertion groove 158 is located inward in the front-rear direction than the positioning rib 82. As a result, when the second bus bar 18b is superimposed on the pressing section 70, the lower opening of each insertion groove 158 is partially covered by both front-rear ends of the second bus bar 18b. In other words, when the second bus bar 18b is superimposed on the pressing section 70, both front-rear ends of the second bus bar 18b protrude outward in the front-rear direction from the bottom surface of each insertion groove 158.

[0087] As described above, in Embodiment 3, the second heat conductive sheet 24b is divided in the left-right direction, and a left second heat conductive sheet 154a and a right second heat conductive sheet 154b are provided that are separated from each other in the left-right direction. Here, the left second heat conductive sheet 154a is superimposed on the left portion of the second bus bar 18b (the portion located to the left of the pressing portion 70 and below the relay 12). The right second heat conductive sheet 154b is superimposed on the portion of the second bus bar 18b corresponding to the space between the left-right insertion grooves 158, 158 that are separated in the left-right direction. In other words, when assembling the circuit component 150, the left and right second heat conductive sheets 154a and 154b are provided at positions that are away from the respective insertion grooves 158 in the left-right direction.

[0088] <Lower Case 160> In Embodiment 3, since the second heat conductive sheet 24b is divided in the left-right direction and left and right second heat conductive sheets 154a and 154b are provided, the second upper housing recess 96b that accommodates the second heat conductive sheet 24b is also divided in the left-right direction in the bottom wall 90 of the lower case 160, and a left second housing recess 162a and a right second housing recess 162b are provided. That is, the left second heat conductive sheet 154a is housed in the left second housing recess 162a, and the right second heat conductive sheet 154b is housed in the right second housing recess 162b. In short, the bottom surfaces of the left second housing recess 162a and the right second housing recess 162b are the left second mounting surface 164a and the right second mounting surface 164b, respectively.

[0089] Furthermore, at the periphery of the right second mounting surface 164b, elastic locking pieces 166 that protrude upward are provided at positions corresponding to each insertion groove 158 of the upper case 156. That is, on both the front-rear and rear-facing sides of the right second mounting surface 164b, there are two elastic locking pieces 166 separated in the left-right direction, and a total of four elastic locking pieces 166 are provided in the lower case 160. As described above, since the right second heat conductive sheet 154b is provided between the left-right insertion grooves 158 that are separated in the left-right direction, the right second heat conductive sheet 154b is accommodated in the right second housing recess 162b (right second mounting surface 164b) between the left-right elastic locking pieces 166 that are separated in the left-right direction.

[0090] Each elastic locking piece 166 has a flexible piece 168 that is elastically deformable on both sides in the front-rear direction, protruding upward from the bottom wall 90 of the lower case 160 and becoming the outer circumference side of the right second heat conductive sheet 154b, and a locking claw portion 170 provided at the protruding end (upper end) of the flexible piece 168 and protruding inward in the front-rear direction. The upper end surface of each locking claw portion 170 is an inclined surface 172 that gradually slopes inward in the left-right direction as it goes downward.

[0091] When assembling the upper case 156 and lower case 160, which have the structure described above, the upper case 156, to which each component is fixed, is positioned opposite the lower case 160 from above. Then, following the guiding action of each guide portion 110 and each guided portion 84, the upper case 156 and lower case 160 are brought closer to each other in the vertical direction. As a result, each insertion groove 158 of the upper case 156 and each elastic lock piece 166 of the lower case 160 face each other in the vertical direction, and each inclined surface 172 of each elastic lock piece 166 abuts against both ends in the front-rear direction of the second bus bar 18b that protrudes to cover the lower opening of each insertion groove 158. Furthermore, by bringing the upper case 156 and lower case 160 closer to each other in the vertical direction, the flexure piece 168 of each elastic lock piece 166 elastically deforms outward in the front-rear direction. Each of these elastic locking pieces 166 elastically returns to its original shape when each locking claw portion 170 overcomes the second bus bar 18b, and each locking claw portion 170 engages with both ends of the second bus bar 18b in the front-rear direction. As a result, the upper case 156 and the lower case 160 are fixed together by the locking mechanism of each elastic locking piece 166 (each locking claw portion 170) (and, if necessary, the press-fit structure of each guided portion 84 into each guide portion 110), and the circuit assembly 150 is completed.

[0092] In Embodiment 3, each locking claw portion 170 engages with the edge of the second busbar 18b which is superimposed on the right-side second heat conductive sheet 154b. That is, each elastic locking piece 166 provided on the lower case 160 is locked to the second busbar 18b fixed to the upper case 156, and the right-side second heat conductive sheet 154b is sandwiched between these second busbars 18b and the bottom wall 90 of the lower case 160 in the vertical direction. By locking each elastic locking piece 166 to the second busbar 18b in this way, the displacement of the right-side second heat conductive sheet 154b sandwiched between the second busbar 18b and the bottom wall 90 is restricted, and in Embodiment 3, the displacement restricting portion 152 is configured including each elastic locking piece 166.

[0093] In the circuit configuration 150 of Embodiment 3, a displacement restricting portion 152 is provided to restrict the displacement of the right-side second heat conductive sheet 154b relative to the lower case 160, thus achieving the same effects as the circuit configuration 150 of Embodiment 1. In particular, in Embodiment 3, each elastic locking piece 166 constituting the displacement restricting portion 152 is not inserted through the second busbar 18b as in Embodiments 1 and 2, but is locked to both ends of the second busbar 18b in the front-rear direction. Therefore, there is no need to provide through holes in the second busbar 18b for inserting the displacement restricting portion 152 (each elastic locking piece 166), and deterioration of conductivity is avoided.

[0094] <Other Embodiments> The technologies described herein are not limited to the embodiments described above in the description and drawings, and the technical scope of the technologies described herein also includes, for example, the following embodiments.

[0095] (1) In the above embodiment, the energizing busbars 18 (first to third busbars 18a to 18c) are equipped with heat transfer sections 40 (first to third heat transfer sections 40a to 40c), and the busbars 18 are used as both energizing and heat transfer busbars. However, the energizing busbars and heat transfer busbars may be used separately. In that case, the energizing busbars and heat transfer busbars may be bolted together and fixed to the connection parts of heat-generating components (e.g., relays and fuses). Also, when the energizing busbars and heat transfer busbars are provided separately, the heat transfer busbars that sandwich a heat-conducting member (e.g., a heat-conducting sheet) between themselves and the lower case may be provided with through holes as in Embodiments 1 and 2, or with a structure in which an elastic locking piece is engaged as in Embodiment 3. There is no need to provide a special structure for the energizing busbars.

[0096] (2) In the above embodiment, each guided portion 84 of the upper cases 58, 132, 156 is inserted in a substantially press-fit state into each guide portion 110 of the lower cases 60, 136, 160, thereby contributing to the fixing of the upper cases 58, 132, 156 and the lower cases 60, 136, 160. However, the embodiment is not limited to this configuration. The upper cases and lower cases may be fixed together by at least one of the following structures: a locking fitting between a locking portion and a locked portion as in Embodiment 1; a press-fitting structure of a press-fitting projection into a press-fitting hole as in Embodiment 2; or a structure in which an elastic locking piece provided on the lower case is engaged with a busbar fixed to the upper case as in Embodiment 3.

[0097] In other words, the guide portion and the guided portion do not necessarily have the function of fixing the upper case and the lower case together; they may simply have the function of guiding the upper case and the lower case toward each other when they are assembled. Furthermore, a locking mechanism or the like for fixing the upper case and the lower case together may be provided separately from the guide portion and the guided portion on the upper circumferential wall of the upper case and the lower circumferential wall of the lower case. Note that the guide portion and the guided portion are not essential in the circuit configuration according to this disclosure.

[0098] (3) In the above embodiments, a plurality of heat conductive sheets 24 are provided as heat conductive members. In embodiments 1 and 2, the displacement of the second heat conductive sheet 24b relative to the lower case 60 and 136 is restricted by displacement restricting parts 118 and 144, and in embodiment 3, the displacement of the right second heat conductive sheet 154b relative to the lower case 160 is restricted by displacement restricting part 152. However, the embodiment is not limited to these embodiments. For example, the displacement of two or more of the plurality of heat conductive members (e.g., heat conductive sheets) provided may be restricted by displacement restricting parts relative to the case.

[0099] Furthermore, among the multiple heat conduction members, those whose displacement relative to the case is not restricted by the displacement restricting portion are not limited to being sandwiched vertically between the heat transfer portion of the busbar and the lower case, as in the above embodiment. That is, for example, a through-window that penetrates the bottom wall of the lower case in the thickness direction may be provided, so that the heat transfer portion makes thermal contact with the heat sink directly or via the heat conduction member through the through-window.

[0100] (4) In the above embodiment 3, the locking claw portion 170 of each elastic locking piece 166 was configured to engage with both ends of the second bus bar 18b in the front-rear direction, but the embodiment is not limited to this configuration. That is, for example, the locking claw portion of the elastic locking piece may be configured to engage with a pressing portion in the upper case that presses the bus bar (for example, the second bus bar) from above.

[0101] (5) In Embodiment 1, a pair of protrusions 100, 100 are provided on the lower case 60 and a locking portion 102 is provided on each protrusion 100, and in Embodiment 2, a pair of protrusions 138, 138 are provided on the lower case 136 and a press-fit projection 142 is provided on each protrusion 138, but the embodiment is not limited to these forms. For example, when multiple protrusions are provided, the embodiment of Embodiment 1 and the embodiment of Embodiment 2 may be adopted in combination, and the embodiment of Embodiment 3 may also be adopted in combination. That is, at least two of the embodiments described in Embodiments 1 to 3 can be adopted in combination.

[0102] (6) In the above embodiment, the displacement restricting parts 118, 144, and 152 were all provided on the lower cases 60, 136, and 160 that constitute the case 20, but they may also be provided on the upper case, for example. That is, for example, the protruding parts constituting the displacement restricting parts may be provided on the upper case, and the locked parts that lock-fit with the locking parts on the protruding parts may be provided on the lower case, or the press-fit holes into which the press-fitting projections on the protruding parts are press-fitted may be provided on the lower case. Alternatively, the elastic locking pieces constituting the displacement restricting parts may be provided on the upper case, and the elastic locking pieces may engage with the edges of the busbars fixed to the lower case. Furthermore, in the above embodiment, when assembling the upper cases 58, 132, 156 and the lower cases 60, 136, 160, the relay 12, fuse 14, and busbars 18 (first to third busbars 18a to 18c) were assembled to the upper cases 58, 132, 156, and the upper cases 58, 132, 156 were assembled to the lower cases 60, 136, 160, thereby fixing the relay 12, fuse 14, and busbars 18 (first to third busbars 18a to 18c) to the lower cases 60, 136, 160 as well. However, the embodiment is not limited to this configuration. That is, heat-generating components (e.g., relays and fuses) and busbars may be assembled to the lower case, and the heat-generating components and busbars may be fixed to the upper case as well when the upper case is assembled to the lower case.

[0103] (7) In Embodiment 3, the second heat conductive sheet 24b was divided in the left-right direction to form left and right second heat conductive sheets 154a, 154b, and these left and right second heat conductive sheets 154a, 154b were positioned away from the positions of each elastic lock piece 166, but the embodiment is not limited to this. That is, in Embodiment 3 as well, a second heat conductive sheet 24b having the same shape as in Embodiments 1 and 2 may be used. In this case, the displacement of the second heat conductive sheet 24b in the front-rear direction may be restricted by the bending piece of each elastic lock piece.

[0104] (8) In the above embodiment, it was described that each heat conductive sheet 24 (first to third heat conductive sheets 24a to 24c, left and right second heat conductive 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) on the bottom wall 90 of the lower cases 60, 136, 160, but the embodiment is not limited to this. That is, for example, each heat conductive member may be fixed in advance to the lower surface of each heat transfer part in each busbar.

[0105] (9) In the above embodiment, the displacement restricting parts 118, 144, and 152 were provided to suppress the displacement of the second heat conductive sheet 24b relative to the case 20 in the front-rear direction, left-right direction (shear direction), and up-down direction (tensile direction), but the invention is not limited to this embodiment. In the circuit configuration according to the present disclosure, it is sufficient that the displacement restricting parts restrict the displacement of the heat conductive member relative to the case in at least one of the front-rear direction, left-right direction, and up-down direction. [Explanation of Symbols]

[0106] 10 Circuit configuration (Embodiment 1) 12 Relays (heat-generating components) 14. Fuses (heat-generating components) 16 Connection part 16a First connection section 16b Second connection section 16c Third connection 16d Fourth connection 18 Bus Bar 18a First bus bar 18b Second bus bar 18c Third bus bar 20 cases 22 Placement surface 22a 1st mounting surface 22b 2nd mounting surface 22c 3rd mounting surface 24. Thermal conductive sheet (thermal conductive material) 24a First thermal conductive sheet 24b Second thermal conductive sheet 24°C Third Thermal Conductive Sheet 26 Relay unit 28 Insulating board 30 Legs 32 Fuse body 34 Bolt insertion holes 36 volts 38 Relay connection section 38a First relay connection 38b Second relay connection 40 Heat transfer section 40a First heat transfer section 40b Second heat transfer section 40c Third heat transfer section 42 Left external connection section 44, 46 Bolt insertion holes 48 Fuse connection 50 Through holes 52 Bolt insertion holes 54 Right external connection 56 Bolt insertion holes 58 Upper Case 60 Lower Cases 62 Upper bottom wall 64 Upper peripheral wall 66a,66b opening 68 Notches 70 Pressing part 72 Weight reduction holes 74 Locked part 76 Cylindrical part 78. Attached claw 80 Slope 82 Positioning Rib 84 Guided part 86 Guided part body 88 Connecting part 90 Bottom wall 92 Lower peripheral wall 94a,94b Support part 96 Upper receiving recess 96a First upper receiving recess 96b Second upper accommodating recess 96c Third upper accommodating recess 98 Lower receiving recess 100 Protrusion 102 Lock section 104 Elastic piece 106 Attaching claws 108 Slope 110 Guide section 112 Guide wall section 114 Notched window 116 Through hole 118 Displacement Control Section 120 volts 130 Circuit configuration (Embodiment 2) 132 Upper Case 134 Cylindrical part 136 Lower Case 138 Protrusion 140 Press-fit hole 142 Press-fitting projection 144 Displacement Control Section 150 Circuit configuration (Embodiment 3) 152 Displacement Control Section 154a Left side second thermal conductive sheet 154b Right side second thermal conductive sheet 156 Upper Case 158 Insertion groove 160 Lower Case 162a Left side second housing recess 162b Right side second storage recess 164a Second mounting surface on the left side 164b Right side second mounting surface 166 Elastic lock pieces 168 Flexible piece 170 Locking claw section 172 Slope

Claims

1. A heat-generating component; a bus bar connected to a connection portion of the heat-generating component; a case that accommodates the heat-generating component and the bus bar; a heat conduction member that is placed on a mounting surface of the case and is in thermal contact with the case and the bus bar and is sandwiched therebetween, The case has a displacement restriction portion that engages with the heat conduction member to restrict displacement of the heat conduction member. circuit construct.

2. the displacement regulating portion has a protruding portion that protrudes from the mounting surface of the case, the heat conduction member has a through hole through which the protrusion is inserted, The circuit assembly according to claim 1 , wherein the bus bar has a through hole that is superimposed on the through hole and through which the protrusion is inserted.

3. the case includes a lower case having the mounting surface, and an upper case assembled to the lower case with the heat conduction member and the bus bar sandwiched between the lower case and the upper case, the upper case has a lockable portion, 3. The circuit assembly according to claim 2, wherein the protrusion includes a locking portion provided on the lower case and lockingly fitted into the locked portion.

4. the upper case has a positioning rib that positions the bus bar, 4. The circuit assembly according to claim 3, wherein the bus bar is positioned by engaging with the positioning rib, and the locked portion of the upper case is positioned with 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 lower case and the upper case have a guide portion and a guided portion that are arranged on the outer circumferential sides of the locking portion and the locked portion, respectively; 5. The circuit structure according to claim 3, wherein, when the upper case is assembled to the lower case, the guided portion is pre-guided by the guide portion, thereby positioning the locked portion of the upper case relative to the lock portion of the lower case.

6. the case includes a lower case having the mounting surface, and an upper case assembled to the lower case with the heat conduction member and the bus bar sandwiched between the lower case and the upper case, the upper case has a press-fit hole, 3. The circuit assembly according to claim 2, wherein the protrusion includes a press-fit protrusion provided on the lower case and press-fitted into the press-fit hole.

7. the displacement restriction portion has an elastic lock piece protruding from a peripheral edge of the mounting surface of the case, The elastic locking piece has a flexible piece that is elastically deformable on the outer circumferential side of the heat conducting member, and a locking claw portion provided on a protruding end of the flexible piece, 3. The circuit assembly according to claim 1, wherein the locking claws engage with edges of the bus bars that are superimposed on the thermally conductive member.

8. the upper case has a pressing portion that brings the bus bar into contact with the heat conduction member, The circuit assembly according to claim 3 , wherein the lockable portion is provided on the pressing portion.

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