Circuit structure

Abstract

To disclose a circuit structure which is excellent in heat radiation efficiency compared to a conventional structure while securing waterproofness.SOLUTION: A circuit structure 10 includes: a case 16 having an opening hole 14 at a bottom part; a heating component 12 which is housed within the case 16, exposed to the outside through the opening hole 14 and thermally contacts with a heat radiation object 18 at the outside; and an annular seal member 22 which is disposed at a peripheral edge part 72 of the opening hole 14 and sandwiched between the case 16 and an assembly member 20 assembled to the case 16.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to circuitry. [Background technology]

[0002] Conventionally, in a circuit configuration including heat-generating components such as relays and fuses that generate heat when energized, a heat dissipation structure for dissipating heat from the heat-generating components may be provided. For example, in Patent Document 1, a connection conductor that is thermally connected to the heat-generating components is in contact with a metal bracket via a sheet-like heat transfer member and a synthetic resin base member. This allows the heat of the heat-generating components to be dissipated from the bracket via the heat transfer member and the base member, and cooled.

[0003] Moreover, such a circuit assembly has a waterproof structure for the purpose of preventing an electrical short circuit, and prevents water from entering the inside of the circuit assembly. In Patent Document 1, as the waterproof structure, a protective wall extending upward is provided on the outer periphery of the base member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-184564 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, heat is dissipated from the heat-generating components via a base member made of synthetic resin. Therefore, when a large amount of heat is expected to be generated from a circuit board on which a semiconductor fuse or a semiconductor relay is mounted, a heat dissipation structure with higher heat dissipation efficiency may be required depending on the heat-generating components.

[0006] Therefore, a circuit assembly is disclosed that ensures waterproofing and has superior heat dissipation efficiency compared to conventional structures. [Means for solving the problem]

[0007] The circuit assembly of the present disclosure comprises a case having an opening at a bottom thereof, a heat generating component housed within the case and exposed to the outside through the opening so as to be in thermal contact with an external heat dissipation target, and an assembly member disposed on the periphery of the opening and sandwiched between the case and the case. The opening hole is surrounded by An annular seal member is provided. The assembly member is constituted by the heat generating component, and the seal member arranged on the peripheral portion of the opening hole of the case is sandwiched between a flange protruding from an outer peripheral portion of the heat generating component and the peripheral portion of the opening hole. It is something that... Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a circuit assembly that ensures waterproofing and has superior heat dissipation efficiency compared to conventional structures. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a circuit assembly according to the first embodiment. [Diagram 2] FIG. 2 is a plan view of the circuit configuration shown in FIG. [Diagram 3] FIG. 3 is an exploded perspective view of the circuit assembly shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is an exploded perspective view of the circuit assembly according to the second embodiment. [Figure 7] FIG. 7 is a vertical cross-sectional view of the circuit configuration shown in FIG. 6 and corresponds to FIG. [Figure 8] FIG. 8 is an exploded perspective view of the circuit assembly according to the third embodiment. [Figure 9] FIG. 9 is a vertical cross-sectional view of the circuit configuration shown in FIG. 8 and corresponds to FIG. [Figure 10] FIG. 10 is an exploded perspective view of the circuit assembly according to the fourth embodiment. [Figure 11]FIG. 11 is a vertical cross-sectional view of the circuit configuration shown in FIG. 10 and corresponds to FIG. [Figure 12] FIG. 12 is an exploded perspective view of the circuit assembly according to the fifth embodiment. [Figure 13] FIG. 13 is a vertical cross-sectional view of the circuit configuration shown in FIG. 12 and corresponds to FIG. [Figure 14] FIG. 14 is a vertical cross-sectional view of a circuit configuration according to another embodiment of the present disclosure, and corresponds to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Description of the embodiments of the present disclosure> First, embodiments of the present disclosure will be listed and described. The circuit configuration of the present disclosure comprises: (1) A device comprising: a case having an opening at the bottom; a heat-generating component housed within the case and exposed to the outside through the opening for thermal contact with an external heat dissipation target; and an annular sealing member disposed on the periphery of the opening and sandwiched between the case and an assembly member assembled to the case.

[0011] According to this structure, an opening is provided in the bottom of the case, the heat generating component is exposed to the outside through the opening, and the heat generating component is in thermal contact with the heat dissipation target. This makes it possible to eliminate synthetic resin members such as the case on the heat dissipation path from the heat generating component to the heat dissipation target, thereby improving heat dissipation efficiency.

[0012] In addition, a ring-shaped seal member is provided around the periphery of the opening hole, and the seal member is sandwiched between the case and an assembly member that is attached to the case. As a result, the opening hole is surrounded by the seal member sandwiched between the case and the assembly member, preventing water from entering the case from outside through the opening hole, and ensuring waterproofing of the circuit assembly. As will be described later, the assembly member that is attached to the case and sandwiches the seal member together with the case may be a heat-generating component, or may be another member, such as a heat sink, that is separate from the heat-generating component and made of a material with higher thermal conductivity than the case.

[0013] (2) It is preferable that the mounting member is composed of the heat-generating component, and at least a portion of the sealing member arranged on the peripheral portion of the opening hole of the case is clamped between a flange protruding from the outer periphery of the heat-generating component and the peripheral portion of the opening hole.

[0014] A flange is provided on the outer peripheral edge of the heat generating component, and at least a part of the seal member is sandwiched between the flange and the peripheral edge of the opening hole to form a surface seal. This allows the area for sandwiching the seal member to be stably secured by simply providing the flange, and the sandwiching of the seal member and the securing of waterproofness can be achieved more reliably. In particular, the shape of the flange can be set arbitrarily according to the shape of the peripheral edge of the opening hole in which the seal member is placed, so that the securing of waterproofness can be achieved reliably with a high degree of design freedom. For example, the flange may be shaped so that the entire area of ​​the seal member is sandwiched between the flange and the peripheral edge of the opening hole, or the flange and the outer peripheral edge of the heat generating component may be combined to sandwich the entire area of ​​the seal member between the peripheral edge of the opening hole.

[0015] (3) It is preferable that the heat generating component contacts an external heat dissipation target directly or via only a heat conductive member. Since the heat generating component contacts the heat dissipation target directly or via only a heat conductive member, the heat of the heat generating component is dissipated directly by the heat dissipation target, improving the heat dissipation efficiency. In order for the heat generating component to contact the heat dissipation target directly or via only a heat conductive member, the heat generating component may be provided with a contact protrusion that contacts the heat dissipation target by inserting through the opening, or the heat dissipation target may be provided with a contact protrusion that contacts the heat generating component in the case by inserting through the opening. In the case of using a heat conductive member, the heat conductive member may be formed of a conventionally known heat conductive sheet or gap filler.

[0016] (4) It is preferable that the heat sink further includes a heat sink covering the opening hole and made of a material having a higher thermal conductivity than the case, the heat generating component is placed in thermal contact with the inner surface of the heat sink, and the outer surface of the heat sink is in thermal contact with an external heat dissipation target. The heat sink made of a material having a higher thermal conductivity than the case is provided on the heat dissipation path from the heat generating component to the heat dissipation target. This improves the heat dissipation efficiency compared to the case where a case is provided on the heat dissipation path as in the conventional structure. The material of the heat sink is selected taking into consideration, for example, strength, weight, cost, etc., and a metal having excellent thermal conductivity is preferably used, and in particular, aluminum or an aluminum alloy is preferable.

[0017] (5) It is preferable that the mounting member is constituted by the heat sink, the inner surface of the heat sink has an accommodating groove in which the seal member is accommodated, and the seal member is sandwiched between the heat sink and the bottom surface of the case placed on the accommodating groove. The provision of the heat sink provides good heat dissipation, while the seal member is sandwiched between the heat sink and the case, ensuring waterproofing of the circuit assembly.

[0018] (6) It is preferable that the assembly member is constituted by the heat sink, the case and the heat sink are integrally formed, and the seal member sandwiched between the periphery of the opening hole of the case and the heat sink is made of a different type of joining material. Since the case and the heat sink are integrally formed, the work of assembling the case and the heat sink and the bolts for assembling can be omitted, and the number of parts when assembling the circuit assembly can be reduced. In addition, a different type of joining material is provided between the case and the heat sink, and for example, a synthetic resin case and a metal heat sink can be joined. This prevents gaps from occurring between the case and the heat sink even due to sink marks or differences in linear expansion coefficients during case molding, and more reliably ensures the waterproofing of the circuit assembly.

[0019] (7) It is preferable that the mounting member is constituted by the heat sink, the heat sink has a protrusion protruding toward the heat generating component, the case has a cylindrical wall portion disposed on the outer periphery side of the outer periphery of the protrusion, and the seal member is sandwiched between the inner periphery of the cylindrical wall portion and the outer periphery of the protrusion, which are disposed opposite each other in the radial direction of the cylindrical wall portion. The provision of the heat sink provides good heat dissipation, while the seal member is sandwiched between the protrusion of the heat sink and the cylindrical wall portion of the case to form an axial seal, thereby ensuring waterproofing of the circuit assembly.

[0020] (8) It is preferable that an annular flange is provided protruding from the outer peripheral edge of the heat generating component, and the annular flange is sandwiched between the peripheral edge of the opening hole and the convex portion of the heat sink. An annular flange is provided protruding from the outer peripheral edge of the heat generating component, and the annular flange is sandwiched between the peripheral edge of the opening hole and the convex portion of the heat sink. In other words, the heat generating component and the case can be assembled so that the annular flange and the peripheral edge of the opening hole engage with each other, and the heat generating component can be positioned relative to the case when assembling the heat generating component and the case. In addition, it is possible to omit the work of assembling the heat generating component and the case and the bolts for assembly.

[0021] (9) It is preferable that the case further includes an insulating member that covers the heat generating component from above, and that the insulating member prevents the heat generating component from being separated from the heat dissipation target by assembling the insulating member to the case. By preventing the heat generating component from being separated from the heat dissipation target by the insulating member, it is possible to suppress the occurrence of gaps between the heat generating component and the heat dissipation target or between the heat generating component and the heat sink, and to stably maintain heat dissipation efficiency.

[0022] <Details of the embodiment of the present disclosure> Specific examples of the circuit configuration of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0023] <Embodiment 1> A circuit assembly 10 according to a first embodiment of the present disclosure will be described below with reference to Figs. 1 to 5. The circuit assembly 10 according to the first embodiment is mounted on a vehicle (not shown), such as an electric vehicle or a hybrid vehicle, and supplies and controls electric power from a power source (not shown) such as a battery to a load (not shown) such as a motor. The circuit assembly 10 can be arranged in any orientation, but in the following description, the X direction in Fig. 1 is the forward direction, the Y direction is the leftward direction, and the Z direction is the upward direction. In addition, for multiple identical members, only some of the members may be labeled with reference numerals, and the reference numerals may be omitted for the other members.

[0024] <Circuit construct 10> As also shown in Fig. 3 to Fig. 5, the circuit assembly 10 includes a semiconductor module 12 as a heat generating component that generates heat when current is applied. The circuit assembly 10 also includes a case 16 having an opening 14 at its bottom, and the opening 14 is formed penetrating the bottom of the case 16 in the vertical direction. The semiconductor module 12 is housed in the case 16, and the semiconductor module 12 is exposed to the outside through the opening 14 and is in thermal contact with a housing 18 of a metal battery pack that is an external heat dissipation target. Furthermore, in the circuit assembly 10, an annular seal member 22 is provided around the opening 14, which is sandwiched between the case 16 and an assembly member (in the first embodiment, a heat sink 20, as described later) that is assembled to the case 16.

[0025] <Semiconductor module 12> Since the semiconductor module 12 is a conventionally known one, detailed description will be omitted. For example, a substrate made of metal or the like (not shown) is provided at the bottom of the semiconductor module 12. Semiconductor chips, switching elements, insulating plates, and the like (not shown) are arranged on this substrate in a predetermined order. Terminals are connected to these semiconductor chips, switching elements, and the like, and they form main circuit terminals 24 that protrude upward inside the semiconductor module 12 and are exposed to the outside at the upper end surface of the semiconductor module 12. The main circuit terminals 24 exposed to the outside of the semiconductor module 12 have bolt holes 26, and nuts 28 communicating with the bolt holes 26 of the main circuit terminals 24 are provided inside the semiconductor module 12. In the first embodiment, three main circuit terminals 24 and nuts 28 are provided at a predetermined distance from each other in the left-right direction. In addition, control terminals 30 that are connected to the semiconductor chips, switching elements, and the like arranged inside the semiconductor module 12 and protrude above the semiconductor module 12 are provided at both left-right ends of the semiconductor module 12.

[0026] The semiconductor module 12 of the first embodiment is generally in the shape of a rectangular block, and is a molded product of insulating synthetic resin. Therefore, in the semiconductor module 12, the parts other than the terminals, chips, nuts, etc. are filled with synthetic resin. As shown in the enlarged view of FIG. 5, in the first embodiment, the outer peripheral edge part of the upper end surface of the semiconductor module 12 is provided with an upper protrusion 32 that protrudes upward from other parts of the upper end surface. As shown in the enlarged view of FIG. 4, the outer peripheral edge part of the lower end of the semiconductor module 12 is formed with a positioning recess 33 that is continuous over the entire circumference in the circumferential direction in a stepped shape. The semiconductor module may be configured such that terminals, chips, nuts, etc. are accommodated and arranged inside a hollow case made of synthetic resin, for example.

[0027] In this semiconductor module 12, the front end of a bus bar 34 extending in the front-rear direction is overlapped with the main circuit terminal 24, and is fastened with a bolt 38 shown by a two-dot chain line in FIG. 4. Specifically, a bolt insertion hole 36 penetrating in the up-down direction is formed in the front end of the bus bar 34. Then, the bolt insertion hole 36 in the bus bar 34 and the bolt hole 26 in the main circuit terminal 24 are aligned with each other, and the bolt 38 is inserted and fastened to the nut 28. At this time, a crimp terminal 42 crimped to an end of an electric wire 40 extending from a wiring pattern (not shown) on a control board 46 described later is overlapped with the bus bar 34. Then, the bolt insertion hole 36, the bolt hole 26, and the bolt hole 44 in the crimp terminal 42 are aligned with each other, and the bolt 38 is inserted and fastened to the nut 28 below the main circuit terminal 24. As a result, the control board 46 connected to the electric wire 40, the bus bar 34, and the main circuit terminal 24 in the semiconductor module 12 are electrically connected.

[0028] A control board 46 to which the electric wire 40 is connected, which will be described later, is provided above the semiconductor module 12. The electric wire 40 extending from the crimp terminal 42 is inserted into a through hole 52 provided in the control board 46, and the end of the electric wire 40 opposite to the side where the crimp terminal 42 is provided is connected to a wiring pattern (not shown) on the control board 46. Furthermore, in the first embodiment, the bus bar 34 and the crimp terminal 42 are bolted to the middle and right main circuit terminals 24 among the three main circuit terminals 24 arranged in the left-right direction. One bus bar 34 is the input side, and the other bus bar 34 is the output side, and the rear end of each bus bar 34 extends rearward beyond the semiconductor module 12. That is, the rear end of the input side bus bar 34 is electrically connected to a power source (not shown), and the rear end of the output side bus bar 34 is electrically connected to a load such as a motor (not shown).

[0029] <Control board 46> The control board 46 has a substantially rectangular plate shape extending in the horizontal direction (a direction perpendicular to the vertical direction) and is made of, for example, synthetic resin having insulating properties. Both the upper and lower surfaces of the control board 46 are provided with a control circuit (not shown) including electronic components such as resistors, coils, capacitors, and diodes (not shown) and a wiring pattern (not shown) that electrically connects these electronic components. The control board 46 is also provided with a connector 48 that protrudes to the outside (upward in the first embodiment), and this connector 48 is connected to an ECU. When the connector 48 and the ECU are connected, the ECU is electrically connected to the control circuit in the control board 46 via a signal line inside the connector 48.

[0030] Furthermore, bolt insertion holes 50 that penetrate in the thickness direction (vertical direction) are provided at the four corners of the control board 46, and a plurality of through holes 52 that penetrate in the thickness direction are provided at predetermined positions on the outer periphery of the control board 46.

[0031] <Insulating member 54> Between each bus bar 34 provided on the semiconductor module 12 and the control board 46, an insulating member 54 made of insulating synthetic resin is provided, and an electrical short circuit caused by contact between the control circuit in the control board 46 and each bus bar 34 is prevented. In the first embodiment, the insulating member 54 is substantially box-shaped and opens downward, and is substantially rectangular in a plan view. That is, the insulating member 54 has a substantially rectangular upper bottom wall portion 56 and a peripheral wall portion 58 that protrudes downward from the outer periphery of the upper bottom wall portion 56. The insulating member 54 is formed to a size that can cover the semiconductor module 12 from above, and is smaller than the control board 46 in a plan view. In particular, in the first embodiment, when the insulating member 54 is assembled to the case 16 in a state where it covers the semiconductor module 12 from above, the peripheral wall portion 58 of the insulating member 54 covers an inner peripheral wall portion 76 of the case 16, which will be described later, from the outer periphery side.

[0032] In addition, the insulating member 54 is provided with a through hole 60 penetrating in the vertical direction at a position corresponding to the control terminal 30 of the semiconductor module 12. As shown in FIG. 5, a substantially cylindrical downward protrusion 62 protruding downward from the upper bottom wall portion 56 is provided on the periphery of the through hole 60, and in the first embodiment, the downward protrusion 62 is a substantially tapered cylindrical shape that gradually reduces in diameter downward. In addition, bolt insertion holes 64 penetrating in the vertical direction are formed at four corners of the insulating member 54. Furthermore, in the insulating member 54, at a portion where the main circuit terminal 24, the bus bar 34, and the crimp terminal 42 are overlapped and fastened by the bolt 38, an accommodating recess 66 for accommodating the bolt 38 is formed to open downward. And, an electric wire insertion hole 68 through which the electric wire 40 is inserted is formed penetrating in the thickness direction in the wall portion constituting the accommodating recess 66.

[0033] <Thermal Conduction Sheet 70> A heat conductive sheet 70 is fixed to the lower surface of the semiconductor module 12 as a heat conductive member. The heat conductive sheet 70 has a rectangular shape that is approximately the same as that of the semiconductor module 12 in a plan view, and covers the entire lower surface of the semiconductor module 12 by being fixed to the lower surface of the semiconductor module 12. The heat conductive sheet 70 has thermal conductivity and insulation properties and is elastically deformable, so that it can be held in close contact between the lower surface of the semiconductor module 12 and the heat sink 20 by being sandwiched between them in the vertical direction. The material of the heat conductive sheet 70 may be, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytetrafluoroethylene (PTFE), polycarbonate (PC), polyimide (PI), or the like. The heat conductive member may be a gap filler that fills the gap between the semiconductor module 12 and the heat sink 20. For ease of understanding, the thickness dimension of the heat conductive sheet 70 is exaggerated in the drawing.

[0034] <Case 16> The case 16 of the first embodiment is generally box-shaped and opens upward, and includes a bottom wall 72 and peripheral walls 74 that protrude upward from the outer periphery of the bottom wall 72 on both front-rear and left-right sides. The case 16 is capable of housing the semiconductor module 12 therein. The upper part of the case 16 may be covered with an upper case (not shown), or the case 16 and the upper case may form a hollow box-shaped body that houses the semiconductor module 12, the insulating member 54, and the control board 46. That is, the case 16 may be a lower case of an electrical connection box that houses the semiconductor module 12, the insulating member 54, and the control board 46.

[0035] The bottom wall 72 of the case 16 is provided with an opening 14 penetrating in the vertical direction in the central portion. In other words, in the case 16, the peripheral portion of the opening 14 is the bottom wall 72. The opening 14 is substantially rectangular in a plan view, and is substantially equal to or slightly larger than the lower surface of the semiconductor module 12 and the thermal conduction sheet 70. A peripheral wall 74 protruding upward is provided on the outer periphery of the opening 14 in the bottom wall 72. As shown in the enlarged view of FIG. 4, a ring-shaped positioning protrusion 75 protruding inward is provided in a stepped shape on the inner periphery of the opening 14 in the bottom wall 72.

[0036] In the first embodiment, the peripheral wall 74 has a triple wall structure that is radially separated from each other, and is composed of an inner peripheral wall portion 76 on the innermost side, an outer peripheral wall portion 78 on the outermost side, and an intermediate wall portion 80 located in the radial middle portion between the inner peripheral wall portion 76 and the outer peripheral wall portion 78. That is, the inner peripheral wall portion 76 is provided on the outer peripheral side of the opening hole 14, the outer peripheral wall portion 78 is provided on the outer peripheral edge portion of the bottom wall 72, and the intermediate wall portion 80 is provided in the radial middle portion of the bottom wall 72. This can advantageously prevent water from entering the inside of the case 16. In addition, bolt insertion holes 82 that penetrate in the vertical direction are formed at the four corners of the inner peripheral wall portion 76 at positions corresponding to the bolt insertion holes 64 of the insulating member 54. In addition, bolt holes 84 into which bolts 94 described later are fastened are formed at the four corners of the intermediate wall portion 80 at positions corresponding to the bolt insertion holes 50 of the control board 46.

[0037] <Heat sink 20> A heat sink 20 having a size large enough to cover the opening 14 of the case 16 is provided on the lower surface of the case 16. The heat sink 20 is made of a material having a higher thermal conductivity than the case 16, and the material is selected in consideration of strength, weight, cost, etc., and is preferably made of metal, for example. In the first embodiment, the heat sink 20 is made of aluminum (including aluminum alloy). In the first embodiment, the heat sink 20 has a substantially rectangular plate shape, and bolt insertion holes 86 are formed at positions corresponding to the bolt insertion holes 64, 82, penetrating in the vertical direction. Furthermore, a cap nut 88 is fixed to the lower surface of the heat sink 20 at positions corresponding to the bolt insertion holes 86.

[0038] On the upper surface, which becomes the inner surface when the heat sink 20 is assembled, an accommodating groove 90 for accommodating the seal member 22 is opened on the outer circumferential side of each bolt insertion hole 86. The accommodating groove 90 is a generally rectangular annular groove that continues around the entire circumference in the circumferential direction, and is provided on the outer circumferential side of the opening hole 14 when the heat sink 20 is fixed to the case 16.

[0039] <Sealing member 22> The seal member 22 has substantially the same shape as the accommodation groove 90 and is substantially rectangular and annular. The seal member 22 is formed of an elastic material such as rubber, and is an O-ring having a circular cross section when in a separate state before being assembled between the case 16 and the heat sink 20. The outer diameter dimension of the circular cross section of the seal member 22 is larger than the depth dimension (vertical dimension) of the accommodation groove 90 in the heat sink 20. As a result, when the seal member 22 is assembled between the case 16 and the heat sink 20, the seal member 22 is compressed between them, and the gap between the case 16 and the heat sink 20 is liquid-tightly sealed by a surface seal.

[0040] <Assembly process of the circuit structure 10> Next, a specific example of the process of assembling the circuit assembly 10 will be described. Note that the process of assembling the circuit assembly 10 is not limited to the following description.

[0041] First, a semiconductor module 12 having a thermally conductive sheet 70 fixed to its underside is prepared, and the crimp terminals 42 provided at the ends of the bus bars 34 and the electric wires 40 are overlapped with the main circuit terminals 24 of the semiconductor module 12. Then, the bolt holes 26, the bolt insertion holes 36, and the bolt holes 44 are aligned with one another, and the bolts 38 are inserted and fastened to the nuts 28. This electrically connects the main circuit terminals 24, the bus bars 34, and the electric wires 40 in the semiconductor module 12.

[0042] Thereafter, with the semiconductor module 12 with the busbars 34 and the electric wires 40 fixed thereto positioned on the inner periphery of the inner periphery wall portion 76 of the case 16, the heat sink 20 with the sealing member 22 accommodated in the accommodation groove 90 is brought close from below so as to cover the opening hole 14 of the case 16. Note that corresponding stepped positioning protrusions 75 and positioning recesses 33 are provided on the inner periphery of the opening hole 14 in the case 16 and the outer periphery of the underside of the semiconductor module 12, so that when the semiconductor module 12 is assembled to the case 16, the semiconductor module 12 and the case 16 are positioned relative to each other in the horizontal direction.

[0043] Furthermore, the insulating member 54 is brought close so as to cover the semiconductor module 12 from above, and the electric wires 40 are inserted into the electric wire insertion holes 68 of the insulating member 54 so as to protrude above the insulating member 54. Then, with the bolt insertion holes 64, 82, 86 aligned with each other, the bolt 92 is inserted and fastened to the cap nut 88 provided on the underside of the heat sink 20.

[0044] As a result, the insulating member 54, the semiconductor module 12, the case 16, and the heat sink 20 are fixed in the vertical direction. That is, the semiconductor module 12 is sandwiched between the insulating member 54 and the heat sink 20, which are connected and fixed by the bolts 92. In this manner, the semiconductor module 12 is placed on the inner surface (upper surface) of the heat sink 20 in a state of thermal contact. In the first embodiment, the lower protrusion 62 of the insulating member 54 and the upper protrusion 32 of the semiconductor module 12 abut against each other or are spaced apart from each other with a slight opposing distance. Therefore, by assembling the insulating member 54 to the case 16, the vertical displacement of the semiconductor module 12 between the case 16 and the insulating member 54 is suppressed. As a result, the insulating member 54 prevents the semiconductor module 12 from being separated from the heat sink 20 and the housing 18, and the contact state between the lower surface (thermal conductive sheet 70) of the semiconductor module 12 and the heat sink 20 can be stably maintained. Therefore, by abutting the lower protrusion 62 and the upper protrusion 32 against each other, the fixing force of the bolt 38 can be applied to the semiconductor module 12 via the lower protrusion 62 and the upper protrusion 32, and the lower surface of the semiconductor module 12 can be pressed against the heat sink 20 via the thermally conductive sheet 70. In short, by assembling the insulating member 54 to the case 16, the heat-generating component (semiconductor module 12) can be pressed against the heat sink 20 by the insulating member 54.

[0045] Furthermore, with the seal member 22 placed in the accommodation groove 90, the bolts 92 are tightened to fix the case 16 and the heat sink 20 together, thereby covering the opening of the accommodation groove 90 with the bottom wall 72 of the case 16. As a result, the seal member 22 is sandwiched in a compressed state between the bottom surface of the case 16, i.e., the lower surface of the bottom wall 72, and the heat sink 20. Therefore, in the first embodiment, the assembly member attached to the case 16 is constituted by the heat sink 20, and the seal member 22 is sandwiched between the case 16 and the assembly member (heat sink 20) ​​on the outer periphery side of the opening hole 14, thereby liquid-tightly sealing the space between the case 16 and the heat sink 20.

[0046] Next, the control board 46 is brought close from above the insulating member 54, and the electric wires 40 are inserted into the through holes 52 of the control board 46, electrically connecting the electric wires 40 to a control circuit (not shown) in the control board 46. Furthermore, the bolt insertion holes 50 in the control board 46 and the bolt holes 84 in the case 16 are aligned with each other, and the bolts 94 are inserted and fastened. This completes the circuit assembly 10 of the first embodiment.

[0047] This circuit assembly 10 is fixed to the metal housing 18 so that the outer surface (lower surface) of the heat sink 20 provided at the bottom is overlapped with and thermally contacts the metal housing 18. Note that recesses may be provided in the housing 18 at positions corresponding to the cap nuts 88, and by accommodating the cap nuts 88 in the recesses, it is also possible to avoid interference between the cap nuts 88 and the housing 18.

[0048] In the circuit assembly 10 of the first embodiment, the semiconductor module 12 is exposed to the outside through the opening hole 14 of the case 16, and a heat sink 20 having a higher thermal conductivity than the case 16 is in contact with the portion of the semiconductor module 12 exposed to the outside. The semiconductor module 12 is in thermal contact with a housing 18, which is an external heat dissipation target, via the heat sink 20. As a result, heat generated in the semiconductor module 12 by the passage of current is dissipated from the housing 18 via the thermally conductive sheet 70 and the heat sink 20.

[0049] Therefore, in the heat dissipation path from the semiconductor module 12 to the housing 18, instead of the synthetic resin case 16, the heat sink 20 having higher thermal conductivity than the case 16 is arranged, thereby improving the heat dissipation efficiency. Also, on the outer peripheral side, which is the periphery of the opening hole 14, the seal member 22 is sandwiched between the case 16 and the heat sink 20, which is an assembly member, so that liquid-tightness is ensured by the surface seal between the case 16 and the heat sink 20, and water is prevented from entering the inside of the circuit assembly 10 through the opening hole 14.

[0050] An accommodating groove 90 for accommodating the seal member 22 is provided on the upper surface of the case 16, and the case 16 and the heat sink 20 are assembled with the seal member 22 placed in the accommodating groove 90. This prevents the seal member 22 from shifting position when the case 16 and the heat sink 20 are assembled, and the gap between the case 16 and the heat sink 20 on the outer periphery side of the opening hole 14 can be sealed liquid-tightly and more stably.

[0051] The semiconductor module 12 has an upper protrusion 32 that protrudes upward, and the insulating member 54 has a lower protrusion 62 that protrudes downward. When assembling the circuit assembly 10, these upper protrusions 32 and lower protrusions 62 can suppress vertical displacement of the semiconductor module 12 between the insulating member 54 and the case 16. Furthermore, by assembling the insulating member 54 to the case 16, it is also possible for the insulating member 54 to press the semiconductor module 12 toward the heat sink 20, and the semiconductor module 12 can be brought into more stable thermal contact with the heat sink 20, thereby further improving the heat dissipation efficiency.

[0052] <Embodiment 2> A circuit configuration 100 according to a second embodiment of the present disclosure will be described below with reference to Figures 6 and 7. The overall configuration of the circuit configuration 100 according to the second embodiment is similar to that of the circuit configuration 10 according to the first embodiment, and in the following description, only the parts that differ from the circuit configuration 10 according to the first embodiment will be described. In addition, the same reference numerals as those in the circuit configuration 10 according to the first embodiment will be used in the drawings to denote members and parts that are substantially the same as those in the circuit configuration 10 according to the first embodiment, and detailed description thereof will be omitted.

[0053] The semiconductor module 102 as the heat generating component in the second embodiment has a flange 104 that protrudes in a substantially annular shape on the outer periphery. Specifically, the flange 104 protrudes on both sides in the front-rear direction and on both sides in the left-right direction at the lower end of the semiconductor module 102. This flange 104 is formed integrally with the resin material that constitutes the semiconductor module 102 (or the hollow case of the semiconductor module) and has insulating properties. The flange 104 has bolt holes 106 formed at multiple locations on the circumference. Also, as shown in FIG. 7, a housing groove 108 that houses the annular seal member 22 is formed on the lower surface of the flange 104. This housing groove 108 is provided on the lower surface of the flange 104 on both sides in the front-rear direction and on both sides in the left-right direction, and is provided at the four corners of the lower surface of the semiconductor module 102 so as to connect them, and is formed in a continuous annular shape around the entire circumference in the circumferential direction as a whole. In addition, when the semiconductor module 102 is assembled to the case 110, the bolt holes 106 in the flange 104 are positioned on the inner side of the opening hole 112, and the accommodating grooves 108 in the flange 104 are positioned on the outer side of the opening hole 112.

[0054] In the second embodiment, the opening hole 112 of the case 110 has substantially the same shape as the semiconductor module 102 including the flange 104 in a plan view, but the size of the opening hole 112 is smaller than that of the semiconductor module 102 including the flange 104. Therefore, as described later, when the semiconductor module 102 is placed in the case 110, the flange 104 of the semiconductor module 102 abuts against the bottom wall 72 which is the periphery of the opening hole 112 of the case 110. Furthermore, the bottom wall 72 of the case 110 has inner periphery bolt holes 114 protruding upward at the four corners on the outer periphery side of the opening hole 112, and has outer periphery bolt holes 116 protruding upward on the outer periphery side of the inner periphery bolt holes 114.

[0055] The heat sink 118 in the second embodiment has a contact protrusion 120 on the upper surface thereof, which protrudes upward and contacts the semiconductor module 102. The contact protrusion 120 has substantially the same shape as the opening hole 112 of the case 110 in a plan view, but the size of the contact protrusion 120 is substantially the same as or slightly smaller than the opening hole 112. Therefore, as described later, when the heat sink 118 is assembled to the case 110, the contact protrusion 120 of the heat sink 118 is adapted to enter the opening hole 112 of the case 110. In addition, the contact protrusion 120 has a plurality of bolt holes 122 in which nuts (not shown) are embedded, at positions corresponding to the respective bolt holes 106 of the flange 104. Furthermore, the thermal conduction sheet 70 in the second embodiment has substantially the same shape as the contact protrusion 120 in a plan view, and has bolt holes 124 penetrating in the thickness direction (vertical direction) at positions corresponding to the respective bolt holes 122 of the contact protrusion 120.

[0056] <Assembly process of the circuit structure 100> First, the sealing member 22 is accommodated in the accommodation groove 108 of the semiconductor module 102 having the thermal conductive sheet 70 fixed to the underside thereof, and the semiconductor module 102 is placed on the bottom wall 72 of the case 110. Alternatively, the sealing member 22 is placed on the bottom wall 72 of the case 110, which is the peripheral portion of the opening hole 112, and the semiconductor module 102 is placed on top of the sealing member 22. The flange 104 of the semiconductor module 102 protrudes in both the front-rear and left-right directions, in other words, has a shape in which the four corners of the periphery are cut out. Meanwhile, the bottom wall 72 of the case 110 has inner periphery bolt holes 114 and outer periphery bolt holes 116 that protrude upward at the four corners of the periphery. As a result, the inner periphery bolt holes 114 and outer periphery bolt holes 116 and the flange 104 exert a positioning effect of positioning the semiconductor module 102 in the horizontal direction relative to the case 110.

[0057] Then, the heat sink 118 is brought close from below the case 110 to align the bolt holes 106, 124, and 122. After that, the bolts 126 are inserted from above into the bolt holes and the bolt holes 106, 124, and 122, and fastened to nuts (not shown) provided on the heat sink 118. As a result, the semiconductor module 102 and the heat sink 118 are fastened to each other by bolts on the inner periphery side of the opening hole 112 in the case 110, and the semiconductor module 102 is brought into thermal contact with the heat sink 118 via the thermal conductive sheet 70. In other words, as shown in the enlarged view of FIG. 7, the flange 104 and the heat sink 118 are bolted to each other on the inner periphery side of the opening hole 112, so that the inner periphery end of the bottom wall 72 of the case 110 is sandwiched between the flange 104 and the heat sink 118 on the outer periphery side of the opening hole 112.

[0058] Also, the seal member 22 is sandwiched in a compressed state on the outer periphery side of the opening hole 112 in the case 110 between the flange 104 and the bottom wall 72 of the case 110, which is the periphery of the opening hole 112, and the gap between the flange 104 (semiconductor module 102) and the case 110 is liquid-tightly sealed by a surface seal by the seal member 22. That is, in the second embodiment, an assembly member that is assembled to the case 110 and sandwiches the seal member 22 together with the case 110 is configured by the semiconductor module 102. More specifically, a part of the seal member 22 is sandwiched between the flange 104 and the bottom wall 72 of the case 110 on both sides in the front-rear direction and both sides in the left-right direction at the periphery of the opening hole 112, and the other part of the seal member 22 is sandwiched between the four corners of the semiconductor module 102 and the bottom wall 72 of the case 110.

[0059] Thereafter, the crimp terminals 42 provided at the ends of the bus bars 34 and the electric wires 40 are overlapped on the main circuit terminals 24 of the semiconductor module 102 and fastened by the bolts 38. Next, the insulating member 54 is brought close from above the semiconductor module 102, and the bolt insertion holes 64 provided at the four corners of the insulating member 54 are aligned with the inner periphery bolt holes 114 provided at the four corners of the case 110. Then, the bolts 128 are inserted into the bolt insertion holes 64 and the inner periphery bolt holes 114 to fasten them. Finally, the control board 46 is brought close from above the insulating member 54, and the bolt insertion holes 50 provided at the four corners of the control board 46 are aligned with the outer periphery bolt holes 116 provided at the four corners of the case 110. Then, the bolts 130 are inserted into the bolt insertion holes 50 and the outer periphery bolt holes 116 to fasten them. This completes the circuit assembly 100 of the second embodiment.

[0060] According to the circuit assembly 100 of the second embodiment, as in the circuit assembly 10 of the first embodiment, a heat sink 118 having higher thermal conductivity is provided on the heat dissipation path instead of the synthetic resin case 110, so that the heat dissipation efficiency is improved. In addition, at the periphery of the opening hole 112, the seal member 22 is compressed between the flange 104 and the bottom wall 72 of the case 110, and the flange 104 (semiconductor module 102) and the case 110 are liquid-tightly sealed by a surface seal. This prevents water from entering from the outside to the inside through the opening hole 112. Note that the seal member 22 prevents water from entering between the flange 104 and the bottom wall 72 of the case 110 from entering from the opening hole 112, but the heat conductive sheet 70 can prevent water from entering from the opening hole 112 to the underside of the semiconductor module 102. This prevents electrical short circuit caused by water that has entered, even if the substrate of the semiconductor module 102 is made of metal.

[0061] In particular, in the second embodiment, the seal member 22 is sandwiched between the wide flange 104 and the periphery of the opening 112, providing a planar sealing effect and more stable waterproofing. Also, the shape of the flange 104 can be set in accordance with the shape of the opening 112, allowing a high degree of freedom in designing the structure for assembling the insulating member 54, the control board 46, etc. while ensuring waterproofing.

[0062] <Embodiment 3> Hereinafter, a circuit assembly 140 according to the third embodiment of the present disclosure will be described with reference to FIGS. 8 and 9. The circuit assembly 140 according to the third embodiment is configured such that the heat sink is not provided in the circuit assembly 100 according to the second embodiment. Therefore, in the third embodiment, a contact protrusion 142 is provided in the housing 18, which protrudes upward and thermally contacts the semiconductor module 102 through the opening hole 112 when assembled to the circuit assembly 140. The contact protrusion 142 has substantially the same shape as the contact protrusion 120 in the circuit assembly 100 according to the second embodiment, and is formed to be substantially the same size as or slightly smaller than the opening hole 112. In the contact protrusion 142, a plurality of bolt holes 122 in which nuts (not shown) are embedded are formed at positions corresponding to the bolt holes 106 of the flange 104.

[0063] <Assembly process of the circuit structure 140> In the second embodiment, the semiconductor module 102 and the heat sink 118 are fastened by the bolts 126, but in the circuit assembly 140 of the third embodiment, the semiconductor module 102 and the housing 18 are fastened by the bolts 126. That is, after the case 110 is placed on the housing 18, the semiconductor module 102 is placed in the case 110. Then, the bolt holes 106, the bolt holes 124, and the bolt holes 122 are aligned, and the bolts 126 are inserted and fastened. As a result, the semiconductor module 102, the case 110, and the housing 18 are fixed by the bolts 126. Thereafter, the bus bar 34 and the electric wires 40 with the crimp terminals 42 are assembled to the main circuit terminals 24 of the semiconductor module 102, and further, the insulating member 54 and the control board 46 are assembled from above, thereby completing the circuit assembly 140 of the third embodiment.

[0064] In the circuit assembly 140 of the third embodiment, the seal member 22 is compressed between the flange 104 of the semiconductor module 102 and the bottom wall 72 of the case 110 at the periphery of the opening 112, thereby preventing water from entering from the outside to the inside through the opening 112. Furthermore, in the circuit assembly 140, the heat sinks 20 and 118 as in the first and second embodiments can be omitted. Therefore, the semiconductor module 102 is in thermal contact with the housing 18 only via the thermally conductive sheet 70, so that the number of components on the heat dissipation path can be reduced, and the heat dissipation efficiency can be further improved.

[0065] <Embodiment 4> Hereinafter, a circuit assembly 150 according to a fourth embodiment of the present disclosure will be described with reference to Figs. 10 and 11. The circuit assembly 150 according to the fourth embodiment has a similar configuration to the circuit assembly 10 according to the first embodiment, but the case 152 and the heat sink 154 are integrally formed. The case 152 and the heat sink 154 according to the fourth embodiment have the same shapes as the case 16 and the heat sink 20 according to the first embodiment. That is, although it is not clear from the drawings, the heat sink 154 according to the fourth embodiment also has bolt insertion holes 86 through which the bolts 92 are inserted at the four corners of the periphery, similar to the heat sink 20 according to the first embodiment, and in the fourth embodiment, nuts are embedded inside.

[0066] In the circuit assembly 150 of the fourth embodiment, a dissimilar joining material 156 for joining dissimilar materials is provided as a sealing member between a synthetic resin case 152 and a metal heat sink 154. As the dissimilar joining material 156, for example, a conventionally known adhesive capable of bonding a synthetic resin member and a metal member can be used, but it is preferable that the dissimilar joining material has elasticity like rubber or elastomer. In the fourth embodiment, "Hytrel (registered trademark)" manufactured by DuPont-Toray Co., Ltd., which is a thermoplastic polyester elastomer, is used.

[0067] <Assembly process of the circuit structure 150> First, heat sink 154 is prepared, and uncured dissimilar bonding material 156 (Hytrel (registered trademark)) is applied in a ring shape to the outer periphery of heat sink 154 (the portion in which housing groove 90 is formed and seal member 22 is housed in embodiment 1). Thereafter, dissimilar bonding material 156 is cured. Then, with heat sink 154 to which dissimilar bonding material 156 is fixed set in the molding cavity of case 152, the molding cavity is filled with the resin material of case 152 to mold case 152. In this way, case 152 is fixed to dissimilar bonding material 156, and case 152 integrally provided with heat sink 154 is obtained. In this integrally formed product of case 152 and heat sink 154, annular dissimilar bonding material 156 is sandwiched between bottom wall 72 of case 152, which is the peripheral portion of opening hole 14, and an upper surface of heat sink 154, which is the surface that comes into contact with case 152. That is, in the fourth embodiment, heat sink 154 constitutes an assembly member that is assembled to case 152 and that, together with case 152, sandwiches dissimilar bonding material 156, which is a sealing member.

[0068] Thereafter, a semiconductor module 12 having a thermally conductive sheet 70 fixed to its underside is prepared and placed on the integrally formed product of the case 152 and the heat sink 154. Next, the bus bar 34 and the crimp terminal 42 are overlapped with the main circuit terminal 24 of the semiconductor module 12 and fixed by fastening the bolts 38. Then, the insulating member 54 is brought close from above the semiconductor module 12, and the bolts 92 are inserted and fastened into the bolt insertion holes 64, 82, and 86. Furthermore, the control board 46 is brought close from above the insulating member 54, and the bolts 94 are inserted and fastened into the bolt insertion holes 50 and the bolt holes 84. This completes the circuit assembly 150 of the fourth embodiment.

[0069] The circuit assembly 150 of the fourth embodiment is attached to the housing 18 so that the lower surface of the heat sink 154 is overlapped with the housing 18. As a result, heat generated in the semiconductor module 12 is dissipated from the housing 18 via the heat sink 154. In addition, at the periphery of the opening 14, the gap between the bottom wall 72 of the case 152 and the heat sink 154 is liquid-tightly sealed by the dissimilar joining material 156, which is a sealing member, thereby preventing water from entering from the outside to the inside through the opening 14.

[0070] In the circuit assembly 150 of the fourth embodiment, the case 152 and the heat sink 154 are integrally formed, so that the number of parts required for assembling the circuit assembly 150 can be reduced, and assembly efficiency can be improved. In addition, the dissimilar joining material 156 is provided between the case 152 and the heat sink 154, so that the synthetic resin member and the metal member, which are difficult to adhere to each other, can be more reliably adhered to each other, and the adhered state can be stably maintained. In particular, a gap is likely to occur between the case and the heat sink due to sink marks during molding of the case, a difference in the linear expansion coefficient between the case and the heat sink, and the like. However, since the dissimilar joining material 156 has elasticity, the occurrence of a gap between the case 152 and the heat sink 154 is prevented by the elastic deformation of the dissimilar joining material 156.

[0071] <Embodiment 5> Hereinafter, a circuit assembly 160 according to a fifth embodiment of the present disclosure will be described with reference to Figs. 12 and 13. For example, in the circuit assembly 10 according to the first embodiment, the semiconductor module 12 is assembled to the case 16 from above, but as in the circuit assembly 160 according to the fifth embodiment, a semiconductor module 162 as a heat generating component may be assembled to the case 164 from below. The semiconductor module 162 according to the fifth embodiment includes an annular flange 166 that protrudes toward the outer periphery over substantially the entire circumference in the circumferential direction at the lower end of the outer periphery of the main body portion 165. The annular flange 166 is provided with four first bolt holes 168 at the four corners, and a plurality of second bolt holes 170 are provided between the first bolt holes 168 in the front-rear direction or between the left-right direction.

[0072] Similarly to the first embodiment, the peripheral wall 74 of the case 164 of the fifth embodiment has a triple-wall structure that is radially spaced apart from one another, and includes an inner peripheral wall portion 76, an outer peripheral wall portion 78, and an intermediate wall portion 80. First bolt insertion holes 172 are provided at four corners of the inner peripheral wall portion 76, and bolt holes 84 are provided at four corners of the intermediate wall portion 80. As shown in the enlarged view of FIG. 13, second bolt insertion holes 174 that penetrate in the up-down direction are provided between the inner peripheral wall portion 76 and the intermediate wall portion 80 in the radial direction in the bottom wall 72 of the case 164, at positions corresponding to the second bolt holes 170 in the annular flange 166.

[0073] Further, a generally cylindrical tube wall portion 176 that protrudes downward is integrally formed on the bottom wall 72 of the case 164. The tube wall portion 176 is formed to be larger than the annular flange 166 in a plan view, and is provided in a radially intermediate portion between the intermediate wall portion 80 and the outer circumferential wall portion 78 in the fifth embodiment.

[0074] The heat sink 178 of the fifth embodiment has a protruding portion 180 protruding toward the semiconductor module 162 side (upper side). The protruding portion 180 has substantially the same shape as the cylindrical wall portion 176 in a plan view, but is formed smaller than the cylindrical wall portion 176. As a result, when the heat sink 178 is assembled to the case 164, the protruding portion 180 enters the cylindrical wall portion 176, and the inner peripheral surface 182 of the cylindrical wall portion 176 and the outer peripheral surface 184 of the protruding portion 180 are arranged to face each other in the radial direction of the cylindrical wall portion 176. In short, when the circuit configuration 160 is assembled, the cylindrical wall portion 176 is arranged on the outer peripheral side of the outer peripheral surface 184 of the protruding portion 180. And, a ring-shaped accommodation groove 90 opening to the outer peripheral side is formed in the outer peripheral surface 184 of the protruding portion 180, and an O-ring-shaped seal member 22 is accommodated in the ring-shaped accommodation groove 90. Furthermore, in the protruding portion 180, at positions corresponding to the first and second bolt holes 168, 170 of the annular flange 166, a plurality of bolt holes 186 in which nuts (not shown) are embedded are formed.

[0075] The thermally conductive sheet 70 fixed to the lower surface of the semiconductor module 162 has substantially the same shape as the lower surface of the semiconductor module 162 including the annular flange 166. In the thermally conductive sheet 70, bolt holes 188 are formed at positions corresponding to the first and second bolt holes 168, 170 of the annular flange 166.

[0076] <Assembly process of the circuit structure 160> First, the semiconductor module 162 having the thermally conductive sheet 70 fixed to its underside is prepared and inserted into the case 164 from below. As a result, the main body portion 165 of the semiconductor module 162 is disposed on the inner periphery side of the inner periphery wall portion 76 of the case 164 through the opening hole 14, and the annular flange 166 is abutted against the bottom wall 72 of the case 164 from below. Next, the heat sink 178 is brought close from below the case 164, and the convex portion 180 of the heat sink 178 is inserted into the cylindrical wall portion 176 of the case 164. Then, with the second bolt insertion holes 174, the second bolt holes 170, the bolt holes 188, and the bolt holes 186 aligned with each other, the second bolts 190 are inserted and fastened.

[0077] As a result, the annular flange 166 is sandwiched between the bottom wall 72, which is the periphery of the opening hole 14, and the convex portion 180 of the heat sink 178 in the vertical direction. In addition, the inner peripheral surface 182 of the tube wall portion 176 and the outer peripheral surface 184 of the convex portion 180 face each other in the radial direction of the tube wall portion 176, and the seal member 22 is sandwiched in a compressed state between the inner peripheral surface 182 of the tube wall portion 176 and the outer peripheral surface 184 of the convex portion 180, which face each other in the radial direction. As a result, the gap extending in the axial direction (vertical direction) of the tube wall portion 176 between the tube wall portion 176 and the convex portion 180 is liquid-tightly sealed by the axial seal of the seal member 22. That is, in the fifth embodiment, the assembly member that is assembled to the case 164 and sandwiches the seal member 22 together with the case 164 is configured by the heat sink 178.

[0078] Next, the bus bar 34 and the crimp terminal 42 are overlapped with the main circuit terminal 24 of the semiconductor module 12 and fixed by fastening the bolt 38. Then, the insulating member 54 is brought close from above the semiconductor module 162, and the first bolts 192 are inserted and fastened through the bolt insertion holes 64, the first bolt insertion holes 172, the first bolt holes 168, the bolt holes 188, and the bolt holes 186. Furthermore, the control board 46 is brought close from above the insulating member 54, and the bolts 94 are inserted and fastened through the bolt insertion holes 50 and the bolt holes 84. This completes the circuit assembly 160 of the fifth embodiment.

[0079] The circuit assembly 160 of the fifth embodiment is attached to the housing 18 so that the lower surface of the heat sink 178 is overlapped with the housing 18. As a result, heat generated in the semiconductor module 162 is dissipated from the housing 18 via the heat sink 178. Also, at the periphery of the opening 14, the middle part in the axial direction (vertical direction) of the insertion part of the protrusion 180 into the cylindrical wall part 176 is liquid-tightly sealed by the seal member 22. As a result, the intrusion of water from the outside to the inside through the opening 14 is prevented.

[0080] In the circuit assembly 160 of the fifth embodiment, the annular flange 166 is inserted into the cylindrical wall portion 176 of the case 164, and the annular flange 166 is superimposed on the bottom wall 72 of the case 164 from below. Also, the convex portion 180 of the heat sink 178 is inserted into the cylindrical wall portion 176 from below the semiconductor module 162, and is superimposed on the lower surface (thermal conduction sheet 70) of the semiconductor module 162. As a result, the semiconductor module 162 is positioned in the horizontal and up-down directions relative to the case 164, and the heat sink 178 is positioned in the horizontal direction relative to the case 164. As a result, the efficiency of assembling the circuit assembly 160 is improved.

[0081] <Other embodiments> The technology described in this specification is not limited to the embodiments described in the above description and drawings, and for example, the following embodiments are also included in the technical scope of the technology described in this specification.

[0082] (1) In the third embodiment, the contact protrusion 142 is provided on the housing 18, and the contact protrusion 142 enters the opening hole 112 and is in thermal contact with the semiconductor module 102. However, as in the circuit configuration 200 shown in FIG. 14, the contact protrusion 202 that comes in contact with the housing 18 may be provided on a semiconductor module 204 as a heat-generating component. Specifically, the semiconductor module 204 has a flange 104 that protrudes on both sides in the front-rear direction and the left-right direction, and a substantially annular contact protrusion 202 is provided on the lower surface of the flange 104. The outer diameter of the contact protrusion 202 is smaller than the inner diameter of the opening hole 112. A substrate of the semiconductor module 204, which is made of metal, for example, is disposed on the inner periphery of the annular contact protrusion 202. As a result, when the circuit configuration 200 is assembled, the contact protrusion 202 and the metal substrate of the semiconductor module 204 can enter the opening hole 112 and be in thermal contact with the flat housing 18. In short, by providing the flange 104 in the semiconductor module 204 a predetermined amount above the lower end of the semiconductor module 204, the main body portion 165 of the semiconductor module 204 can be inserted into the opening 112 in a state in which the flange 104 is abutted from above against the bottom wall 72 of the case 110, which is the periphery of the opening 112. Therefore, the semiconductor module 204 can be brought into contact with the flat housing 18 that does not have a special shape, for example, via the thermally conductive sheet 70.

[0083] (2) In the above-described embodiment, the heat-generating component is the semiconductor module 12, 102, or 162, but the heat-generating component may be a relay or a fuse. When the heat-generating component is a relay or a fuse, the housing of the relay or fuse may be exposed to the outside through an opening in the case and be in thermal contact with a heat dissipation target, or a bus bar fixed to a connection portion of the relay or fuse may be exposed to the outside through an opening in the case and be in contact with a heat dissipation target.

[0084] (3) In the second embodiment, a portion of the sealing member 22 was clamped between the flange 104 and the peripheral edge (bottom wall 72) of the opening hole 112, but the entire area of ​​the sealing member may be clamped between the annular flange and the peripheral edge of the opening hole.

[0085] (4) In the above embodiment, the insulating member 54 is fixed to the case or the heat sink with bolts, but the method of fixing the insulating member to the case is not limited to bolts. For example, the insulating member may be fixed to the case by providing claws protruding inward on the peripheral wall of the case, and the insulating member may ride over the claws to engage with the insulating member and the claws.

[0086] (5) In the above embodiment, the thermally conductive sheet 70 is attached to the bottom surface of the heat generating component (semiconductor module 12, 102, 162), but it may be attached to a heat sink or the top surface of the housing instead of the bottom surface of the heat generating component. Note that when the housing of a heat generating component such as a relay or fuse is made of synthetic resin, or when the bottom surface of a semiconductor module is covered with a synthetic resin material, the thermally conductive sheet is not essential.

[0087] (6) For example, in the first embodiment, the seal member 22 is an O-ring made of rubber or the like and having a circular (O-shaped) cross section, but it may be an annular elastic body having a cross section other than a circular shape (for example, a D-ring, an X-ring, a T-ring, etc.), or may be a liquid packing or the like. In the first embodiment, the accommodating groove 90 for accommodating the seal member 22 is provided in the heat sink 20, but it may be provided in the bottom wall of the case facing the heat sink in addition to or instead of the heat sink. Similarly, in the second and third embodiments, the accommodating groove may also be provided in the bottom wall of the case facing the flange in the up-down direction, and in the fifth embodiment, the accommodating groove may also be provided in the cylindrical wall of the case facing the convex portion of the heat sink in the horizontal direction. [Explanation of symbols]

[0088] 10 Circuit structure (embodiment 1) 12 Semiconductor modules (heat generating components) 14 Opening hole 16 cases 18 Chassis (heat dissipation target) 20 Heat sink (assembly part) 22 Sealing material 24 Main circuit terminal 26 Bolt holes 28 Nut 30 Control terminal 32 Upper protrusion 33 Positioning recess 34 Busbar 36 Bolt insertion hole 38 Volts 40 Electric wire 42 Crimp terminal 44 Bolt holes 46 Control Board 48 Connectors 50 Bolt hole 52 through hole 54 Insulating materials 56 Upper bottom wall 58 Peripheral wall section 60 Through Hole 62 Lower protrusion 64 Bolt insertion hole 66 Storage recess 68 Wire insertion hole 70 Thermally conductive sheet (thermal conductive material) 72 Bottom wall (periphery) 74 Peripheral wall 75 Positioning protrusion 76 Inner peripheral wall 78 Outer wall 80 Intermediate wall 82 Bolt insertion hole 84 Bolt Holes 86 Bolt insertion hole 88 Cap nut 90 Storage groove 92,94 Volts 100 Circuit structure (embodiment 2) 102 Semiconductor modules (heat generating parts, assembly materials) 104 Flange 106 Bolt hole 108 Storage groove 110 cases 112 Opening hole 114 Inner Bolt Hole 116 Outer bolt hole 118 Heat sink 120 Contact protrusion 122 Bolt Hole 124 Bolt holes 126,128,130 volts 140 Circuit structure (embodiment 3) 142 Contact protrusion 150 Circuit structure (embodiment 4) 152 cases 154 Heat sink (assembly part) 156 Dissimilar bonding materials (sealing materials) 160 Circuit structure (embodiment 5) 162 Semiconductor modules (heat generating components) 164 cases 165 Main body part 166 Annular flange 168 First bolt hole 170 Second bolt hole 172 First bolt hole 174 Second bolt hole 176 Cylinder wall 178 Heat sink (assembly part) 180 Convex 182 (Cylinder wall) inner surface 184 (Convex) Outer Surface 186 Bolt Hole 188 Bolt holes 190 Second Bolt 192 First Bolt 200 Circuit structure (Fig. 14) 202 Contact protrusion 204 Semiconductor module (heat generating component)

Claims

1. A case having an opening at a bottom thereof; a heat generating component housed in the case and exposed to the outside through the opening and in thermal contact with an external heat dissipation target; an annular seal member disposed on a periphery of the opening and sandwiched between the case and an assembly member assembled to the case to surround the opening; Equipped with the assembly member is formed of the heat generating component, A circuit structure, wherein the sealing member arranged on the peripheral portion of the opening hole of the case is sandwiched between a flange protruding from an outer periphery of the heat-generating component and the peripheral portion of the opening hole.

2. 2. The circuit assembly according to claim 1, wherein the heat generating component is in direct contact with an external heat dissipation target or is in contact with only a heat conductive member.

3. A heat sink is further provided, the heat sink covering the opening and made of a material having a higher thermal conductivity than the case. The heat generating component is placed in thermal contact with the inner surface of the heat sink, 2. The circuit assembly according to claim 1, wherein an outer surface of the heat sink is in thermal contact with an external heat dissipation target.

4. A case having an opening hole at the bottom, a heat generating component housed in the case and exposed to the outside through the opening and in thermal contact with an external heat dissipation target; an annular seal member disposed on a periphery of the opening and sandwiched between the case and an assembly member assembled to the case to surround the opening; Equipped with A heat sink is further provided, the heat sink covering the opening and made of a material having a higher thermal conductivity than the case. The heat generating component is placed in thermal contact with the inner surface of the heat sink, The outer surface of the heat sink is in thermal contact with an external heat dissipation target; The assembly member is constituted by the heat sink, The case and the heat sink are integrally formed, a sealing member sandwiched between the peripheral portion of the opening of the case and the heat sink, the sealing member being made of a different bonding material.

5. A case having an opening hole at the bottom, a heat generating component housed in the case and exposed to the outside through the opening and in thermal contact with an external heat dissipation target; an annular seal member disposed on a periphery of the opening and sandwiched between the case and an assembly member assembled to the case to surround the opening; Equipped with A heat sink is further provided, the heat sink covering the opening and made of a material having a higher thermal conductivity than the case. The heat generating component is placed in thermal contact with the inner surface of the heat sink, The outer surface of the heat sink is in thermal contact with an external heat dissipation target; The assembly member is constituted by the heat sink, the heat sink has a protrusion protruding toward the heat generating component, the case has a cylindrical wall portion provided on the peripheral edge portion of the opening hole and disposed on the outer circumferential side of an outer circumferential surface of the protrusion, a circuit assembly, the seal member being sandwiched between an inner peripheral surface of the cylindrical wall portion and an outer peripheral surface of the protrusion, the inner peripheral surface and the protrusion being disposed opposite each other in a radial direction of the cylindrical wall portion.

6. An annular flange is provided on the outer circumferential edge of the heat generating component, 6. The circuit assembly according to claim 5, wherein the annular flange is sandwiched between the peripheral edge of the opening and the protruding portion of the heat sink.

7. Further, an insulating member is provided to cover the heat generating component from above.

7. The circuit assembly according to claim 1, wherein the insulating member prevents the heat generating component from being separated from a heat dissipation target by assembling the insulating member to the case.

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