Circuit structure

Abstract

Disclosed is a circuit structure with a new structure that can quickly reduce the heat generation of the connection part of a heat-generating component. The circuit structure (10) includes: a heat-generating component (12) that generates heat due to energization; an energization member (16) connected to the connection part (14) of the heat-generating component (12); a connection member (18) that connects the energization member (16) to the connection part (14); and a heat capacity increasing component (20) that makes thermal contact with the connection part between the energization member (16) and the connection part (14) to increase the heat capacity of the connection part (14) of the heat-generating component (12).

Description

Technical Field

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

[0002] Conventionally, in a circuit structure having a heat generating component such as a relay or a fuse that generates heat when energized, a heat dissipation structure for dissipating the heat of the heat generating component is sometimes provided. For example, Patent Document 1 proposes a structure for dissipating heat of a relay by using an intermediate portion of a bus bar that connects a connection portion of a relay housed in a housing to a connection terminal of a storage battery disposed outside the housing. Specifically, a structure is disclosed in which the intermediate portion of the bus bar extending outside the housing that houses the relay is brought into contact with a chassis, a housing that houses the entire power supply device, etc. via an insulating heat sink, and thereby heat generated by the relay is conducted to the chassis and the housing for heat dissipation.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-79093 Summary of the Invention

[0006] Outline of the Invention

[0007] Problems to be Solved by the Invention

[0008] In the structure of Patent Document 1, a heat dissipation structure is provided in the intermediate portion of the bus bar that constitutes the energization portion connecting the relay and the storage battery. Therefore, there is a concern that although heat dissipation of the relay via the bus bar can be promoted, heat generation at the connection portion of the relay cannot be rapidly reduced when a large current flows.

[0009] Therefore, a circuit structure having a new structure that can rapidly reduce heat generation at the connection portion of a heat generating component is disclosed.

[0010] Means for Solving the Problems

[0011] The circuit structure of the present disclosure includes: a heat generating component that generates heat when energized; an energization member connected to a connection portion of the heat generating component; a connection member that connects the energization member to the connection portion; and a heat capacity increasing component that makes thermal contact with a connection portion between the energization member and the connection portion to increase the heat capacity of the connection portion of the heat generating component.

[0012] Advantages of the Invention

[0013] According to the present disclosure, heat generation at the connection portion of a heat generating component can be rapidly reduced. Brief Description of the Drawings

[0014] Figure 1 This is a perspective view showing the circuit structure of Embodiment 1.

[0015] Figure 2 This is Figure 1 an exploded perspective view showing the state where the lid member constituting the housing is removed from the circuit structure shown.

[0016] Figure 3 This is Figure 1 an exploded perspective view of the circuit structure shown.

[0017] Figure 4 This is a perspective view showing the energizing member constituting the Figure 1 circuit structure shown.

[0018] Figure 5 This is Figure 2 a sectional view taken along the line V-V of

[0019] Figure 6 This is a perspective view showing the circuit structure of Embodiment 2, which is an enlarged view of the main part in the state where the lid member constituting the housing is removed.

[0020] Figure 7 This is Figure 6 a sectional view taken along the line VII-VII of

[0021] Figure 8 This is a perspective view showing the circuit structure of Embodiment 3, which is an enlarged view of the main part in the state where the lid member constituting the housing is removed.

[0022] Figure 9 This is Figure 8 a sectional view taken along the line IX-IX of

[0023] Figure 10 This is a longitudinal sectional view showing the circuit structure of Embodiment 4, which is a view corresponding to Figure 9 Detailed Embodiments

[0024] <Description of Embodiments of the Present Disclosure>

[0025] First, embodiments of the present disclosure will be listed and described.

[0026] In the circuit structure of the present disclosure,

[0027] (1) It includes: a heating component that generates heat when energized; an energizing member connected to the connection portion of the heating component; a connecting member that connects the energizing member to the connection portion; and a heat capacity increasing component that makes thermal contact with the connection portion between the energizing member and the connection portion to increase the heat capacity of the connection portion of the heating component.

[0028] ​According to the circuit structure of the present disclosure, there is a heat capacity increasing component, which is in thermal contact with the connection part of the heat generating part that becomes the heat generating site and the connection part of the energizing member connected to the connection part, so as to increase the heat capacity of the connection part. Therefore, for the heat of the connection part that transfers heat to the connection part of the heat generating part and the connection part of the energizing member, the temperature rise is suppressed by the heat capacity increasing component in thermal contact with the connection part, and the heat of the connection part can be reduced. As a result, compared with the conventional structure in which the energizing member is in thermal contact with other members at a position separated from the connection part of the heat generating part for heat dissipation, the heat capacity increasing component can be used to quickly reduce the heat generation of the connection part of the heat generating part. It should be noted that the heat generating parts include components that generate heat due to energization, such as relays and fuses.

[0029] The heat capacity increasing component is in thermal contact with the connection part of the connection part and the energizing member. Thus, as long as the heat capacity of the connection part of the heat generating part can be increased, it can be any structure. For example, a structure made of metals such as iron, copper, aluminum, and their alloys with high thermal conductivity, or a structure made of synthetic resin can be adopted. Moreover, the shape of the heat capacity increasing component is not particularly limited as long as it can be in thermal contact with the connection part of the connection part and the energizing member, and any shape can also be adopted.

[0030] As a connecting member, as long as it can be used for connecting the energizing member, any well-known connecting member can be adopted, and bolts, rivets, etc. can be advantageously adopted.

[0031] (2) Preferably, the circuit structure further includes a heat conducting member and a housing, and the energizing member is in thermal contact with the housing via the heat conducting member. The heat transferred to the energizing member can be dissipated from the housing through the heat conducting member. Therefore, the heat of the heat generating part can be reduced. In this embodiment, a sheet-like heat conducting member can be preferably adopted, for example.

[0032] (3) Preferably, the heat capacity increasing component is made of metal, and the heat capacity increasing component is connected to the connection part together with the energizing member by the connecting member. This is because the heat capacity increasing component is made of metal and is connected to the connection part together with the energizing member, so that the heat capacity of the connection part can be easily and reliably increased. It should be noted that the heat capacity increasing component can be formed integrally with the energizing member or can be a component separated from the energizing member.

[0033] (4) Preferably, the heat capacity increasing member overlaps the surface on the opposite side of the contact surface of the energizing member that contacts the connecting portion. Since the heat capacity increasing member overlaps the surface on the opposite side of the contact surface of the energizing member that contacts the connecting portion, when the connecting portion is connected by the connecting member, it is possible to avoid the situation where the heat capacity increasing member is interposed between the energizing member and the connecting portion. Therefore, it is possible to increase the heat capacity of the connecting portion without increasing the conduction resistance.

[0034] (5) Preferably, the heat capacity increasing member is constituted by an end portion of the energizing member, which is folded back and overlaps the surface on the opposite side of the contact surface of the energizing member that contacts the connecting portion. Since the heat capacity increasing member is constituted by an end portion of the energizing member, it is possible to suppress an increase in the number of components. Moreover, since it is folded back and overlaps the surface on the opposite side of the contact surface of the energizing member that contacts the connecting portion, when the connecting portion is connected by the connecting member, it is possible to avoid the situation where the heat capacity increasing member is interposed between the energizing member and the connecting portion. Therefore, it is possible to increase the heat capacity of the connecting portion without increasing the conduction resistance.

[0035] (6) Preferably, a holding portion is provided on the energizing member, and the holding portion holds the overlapping state of the end portion of the energizing member constituting the heat capacity increasing member and the surface on the opposite side of the contact surface of the energizing member that contacts the connecting portion. By the holding portion, it is possible to suppress the gap between the energizing member and the heat capacity increasing member (the folded-back end portion of the energizing member) to be small, and it is possible to make the energizing member and the heat capacity increasing member have a large contact area and contact stably. Thus, it is possible to increase the heat capacity of the connecting portion more reliably.

[0036] (7) Preferably, the linear expansion coefficient of the heat capacity increasing member is 1 / 3 to 3 times the linear expansion coefficient of the connecting member. This is because, since the heat capacity increasing member has a linear expansion coefficient similar to that of the connecting member, it is difficult to cause loosening of the connecting member due to heat generation.

[0037] (8) Preferably, the heat capacity increasing member and the connecting member are made of the same material. Since the linear expansion coefficients of the heat capacity increasing member and the connecting member are equal, it is possible to more reliably suppress loosening of the connecting member due to heat generation.

[0038] (9) Preferably, the heat capacity increasing member is constituted by a cap fitted to the connecting member. This is because, even if it is a cap fitted to the connecting member, it is possible to increase the heat capacity of the connecting portion and quickly reduce the heat generation of the connecting portion of the heat generating component.

[0039] (10) Preferably, the cap is made of metal. By using a metal cap with a high thermal conductivity, it is possible to suppress the temperature rise of the connecting portion.

[0040] (11) Preferably, a heat conducting member is provided between the cap and the connecting member. Through the heat conducting member, heat can be stably transferred from the connecting member to the cap. In this embodiment, a heat conducting member in the form of, for example, grease is preferably used.

[0041] (12) Preferably, the cap is made of synthetic resin. As the material of the cap, by using, for example, synthetic resin that is softer than metal, the cap can be assembled to the connecting member with substantially no gap. Thus, heat can be stably transferred from the connecting member to the cap, and the heat capacity of the connecting portion can be increased more reliably.

[0042] <Details of the Embodiment of the Present Disclosure>

[0043] Hereinafter, with reference to the drawings, specific examples of the circuit structure of the present disclosure will be described. It should be noted that the present disclosure is not limited to these examples, is disclosed by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0044] <Embodiment 1>

[0045] Hereinafter, regarding Embodiment 1 of the present disclosure, reference will be made to Figures 1 - 5 for description. The circuit structure 10 of Embodiment 1 is mounted on a vehicle (not shown) such as an electric vehicle or a hybrid vehicle, and supplies and controls electric power from a power source (not shown) such as a storage battery to a load (not shown) such as an electric motor. The circuit structure 10 can be arranged in any orientation, but hereinafter, the X direction will be set as the front, the Y direction will be set as the right, and the Z direction will be set as the upper for description. Moreover, for a plurality of identical members, only some of the members are labeled, and for other members, the labels may be omitted.

[0046] <Circuit Structure 10>

[0047] The circuit structure 10 includes: a relay 12 as a heat generating component that generates heat when energized; a power supply bus bar 16 as an energized member connected to the connection portion 14 of the relay 12; a bolt 18 as a connecting member that connects the power supply bus bar 16 to the connection portion 14 of the relay 12. Moreover, the circuit structure 10 includes a heat capacity increasing component 20 that is in thermal contact with the connection portion A (in the figure, the region surrounded by the double-dot chain line) between the power supply bus bar 16 and the connection portion 14. In addition, the circuit structure 10 includes a housing 22. The relay 12, the power supply bus bar 16, the bolt 18, and the heat capacity increasing component 20 are all housed in the housing 22. In addition, a fuse 24 and a current sensor 26 that generate heat when energized are housed in the housing 22.

[0048] <Housing 22>

[0049] The housing 22 is generally box-shaped and is formed of, for example, synthetic resin. In Embodiment 1, the housing 22 has a substantially rectangular shape extending in the left-right direction when viewed from above. The housing 22 is vertically divisible and includes a base member 28 located below and a lid member 30 located above. The base member 28 has a box shape that opens upward. Further, the lid member 30 has a box shape that opens downward. Then, the upper opening of the base member 28 is covered with the lid member 30, and the base member 28 and the lid member 30 are fixed to each other, whereby the housing 22 is constituted. The fixing method of the base member 28 and the lid member 30 is not limited, and conventionally known fixing methods such as adhesion, welding, press-fitting, and concavo-convex fitting can be adopted. Note that the housing 22 may be made of metal, or insulation may be ensured by providing an insulating coating on the surface of the housing 22.

[0050] The base member 28 includes: a bottom wall 32 having a substantially rectangular shape extending in the left-right direction; and a peripheral wall 34 protruding upward from the outer peripheral edge of the bottom wall 32. In Embodiment 1, a rectangular first accommodation recess 36 that opens upward is formed on the upper surface of the bottom wall 32. That is, a step 38 is formed on the upper surface of the bottom wall 32, and the portion surrounded by the step 38 is the first accommodation recess 36. Particularly in Embodiment 1, among the upper surface of the bottom wall 32, four first accommodation recesses 36 are formed with a prescribed size and a prescribed separation distance in the left-right direction.

[0051] Also as Figure 5 shown, on the lower surface of the bottom wall 32, rectangular second accommodation recesses 40 that open downward are formed at positions corresponding to the first accommodation recesses 36. That is, a step 42 is formed on the lower surface of the bottom wall 32, and the portion surrounded by the step 42 is the second accommodation recess 40. Four of these second accommodation recesses 40 are provided with sizes and positions corresponding to the first accommodation recesses 36. Therefore, in Embodiment 1, at the formation positions of the first and second accommodation recesses 36 and 40, the bottom wall 32 is thinner than other portions.

[0052] The lid member 30 includes: an upper bottom wall 44 having a substantially rectangular shape extending in the left-right direction; and a peripheral wall 46 protruding downward from the outer peripheral edge of the upper bottom wall 44. In Embodiment 1, rectangular openings 48a and 48b that penetrate in the vertical direction are formed at both ends in the left-right direction of the upper bottom wall 44. Further, a plurality of bolt insertion holes 50 that penetrate in the vertical direction are formed in the outer peripheral portion of the lid member 30.

[0053] <Relays 12, fuses 24, current sensors 26>

[0054] The relay 12 has a relay body 52 having a hollow rectangular parallelepiped shape. On the front surface of the relay body 52, a pair of connection parts 14, 14 (a first connection part 14a and a second connection part 14b) are provided separately from each other in the left-right direction. An insulating plate 54 protruding forward is provided between the first connection part 14a and the second connection part 14b described above.

[0055] In addition, a plurality of legs 56 protruding outward in the left-right direction are provided on the relay body 52. Bolt insertion holes penetrating in the up-down direction are formed in these legs 56.

[0056] The fuse 24 has a fuse body 60 having a substantially rectangular parallelepiped shape. Metal connection parts 62, 62 protruding to both sides in the left-right direction are provided on the fuse body 60. Bolt insertion holes penetrating in the up-down direction are formed in the connection parts 62, 62 described above.

[0057] The current sensor 26 has a sensor body 66 having a substantially rectangular parallelepiped shape. Metal connection parts 68, 68 protruding to both sides in the left-right direction are provided on the sensor body 66. Bolt insertion holes penetrating in the up-down direction are formed in the connection parts 68, 68 described above.

[0058] <Power supply bus bar 16>

[0059] The power supply bus bar 16 is formed by bending a metal plate into a predetermined shape by stamping or the like. The material of the power supply bus bar 16 is not limited, but copper, copper alloy, aluminum, aluminum alloy, etc. are preferably used. It should be noted that the linear expansion coefficient of copper is about 16 - 17 (×10 -6 / K) or so. Moreover, the linear expansion coefficient of aluminum is about 23 - 24 (×10 -6 / K) or so. In Embodiment 1, as also Figure 4 shown, a pair of power supply bus bars 16, 16 (a first power supply bus bar 16a and a second power supply bus bar 16b) are provided separately from each other in the left-right direction.

[0060] The first power supply bus bar 16a extends in the left-right direction as a whole. The first power supply bus bar 16a has a rectangular bolt connection part 72 extending in the up-down direction (YZ plane) at its right end. A rectangular heat transfer part 74 extending in the horizontal direction (XY plane) extends rearward from the lower end of the bolt connection part 72. Moreover, the first power supply bus bar 16a has a rectangular external connection part 76 extending in the horizontal direction (XY plane) at its left end. And the heat transfer part 74 and the external connection part 76 are connected by a part bent in a crank shape in the middle part in the left-right direction.

[0061] In addition, the upper end part of the bolt connection part 72 of the first power supply bus bar 16a is folded back forward and overlaps with the lower end part of the bolt connection part 72. It should be noted that inFigure 4 In Figure 4 , the upper end portion of the bolt connection portion 72 before folding back is indicated by a double-dashed line. The folded and overlapping portion is the heat capacity increasing member 20. That is, in Embodiment 1, the heat capacity increasing member 20 is made of metal and is the same material as the energized bus bars 16 (the first and second energized bus bars 16a, 16b). Moreover, the first energized bus bar 16a is formed at the formation position of the heat capacity increasing member 20 with a thickness dimension of two times. Further, the rear surface of the bolt connection portion 72 is a contact surface 78 that contacts the first connection portion 14a of the relay 12. Therefore, the upper end portion (the heat capacity increasing member 20) of the bolt connection portion 72, which is the end portion of the first energized bus bar 16a, is on the front surface 79 of the bolt connection portion 72 that overlaps the surface on the side opposite to the contact surface 78.

[0062] In addition, a holding portion 80 for holding the overlapping state of the heat capacity increasing member 20 and the front surface 79 of the bolt connection portion 72 is provided in the first energized bus bar 16a. The shape of the holding portion 80 is not limited, but in Embodiment 1, the holding portion 80 is a metal member integrally formed with the first energized bus bar 16a. Specifically, a pair of strip-shaped holding portions 80, 80 are respectively provided on both sides in the left-right direction of the bolt connection portion 72. And, in a state where the heat capacity increasing member 20 (the upper end portion of the bolt connection portion 72) overlaps the front surface 79 of the bolt connection portion 72, the overlapping state of the heat capacity increasing member 20 (the upper end portion of the bolt connection portion 72) is held by bending and riveting the holding portions 80, 80.

[0063] Further, a bolt insertion hole 82 penetrating in the front-rear direction is formed in the bolt connection portion 72. In Embodiment 1, the bolt insertion hole 82 is formed in the portion where the heat capacity increasing member 20 is provided (the portion where the upper end portion of the bolt connection portion 72 is folded back and overlapped). Therefore, the bolt insertion hole 82 is formed by penetrating the portion with a thickness dimension of two times that of the first energized bus bar 16a in the front-rear direction. It should be noted that, before folding back the upper end portion of the bolt connection portion 72, through holes may be respectively formed in the upper end portion and the lower end portion of the bolt connection portion 72, and the upper end portion of the bolt connection portion 72 is folded back so that the two through holes communicate with each other, thereby forming the bolt insertion hole 82. Alternatively, after folding back and overlapping the upper end portion of the bolt connection portion 72, the bolt insertion hole 82 may be formed in the portion with a thickness dimension of two times. The bolt 18 is inserted into the bolt insertion hole 82 and connected to the first connection portion 14a, thereby fixing the first energized bus bar 16a having the heat capacity increasing member 20. In other words, through the connection of the bolt 18, not only the first energized bus bar with a thickness dimension of one time, but also the heat capacity increasing member 20 having another thickness dimension is fixed to the first connection portion 14a together.

[0064] In addition, in Embodiment 1, the bolt insertion through-hole 82 has an oblong shape elongated in the vertical direction. Thereby, when connecting the relay 12 and the first power-conducting bus bar 16a described later, the vertical position of the first power-conducting bus bar 16a relative to the relay 12 can be adjusted. As a result, as described later, the heat transfer portion 74 can be made to thermally contact the housing 22 (or the heat-conducting sheet 114 described later) more reliably. Further, a bolt insertion through-hole 84 penetrating in the thickness direction (vertical direction) is formed in the external connection portion 76.

[0065] The second power-conducting bus bar 16b has a shape substantially symmetric with the first power-conducting bus bar 16a in the left-right direction. That is, a bolt connection portion 72 is provided in front of the left end portion of the second power-conducting bus bar 16b. The heat transfer portion 74 extends rearward from the lower end portion of the bolt connection portion 72. Further, a rectangular fuse connection portion 86 extending in the horizontal direction (XY plane) is provided at the right end portion of the second power-conducting bus bar 16b. The heat transfer portion 74 and the fuse connection portion 86 are connected by a portion bent in a crank shape at the middle portion in the left-right direction. Further, a bolt insertion through-hole 88 penetrating in the thickness direction (vertical direction) is formed in the fuse connection portion 86.

[0066] Moreover, the upper end portion of the bolt connection portion 72 in the second power-conducting bus bar 16b is folded back forward to constitute the heat capacity increasing member 20. Further, by the holding portions 80, 80, it is held in a state where the heat capacity increasing member 20 (the upper end portion of the bolt connection portion 72) is folded back and overlaps the front surface 79. In addition, in a state where the heat capacity increasing member 20 is provided, a bolt insertion through-hole 82 penetrating in the thickness direction (front-rear direction) is formed in the bolt connection portion 72. A bolt 18 is inserted through the bolt insertion through-hole 82 and connected to the second connection portion 14b, whereby the second power-conducting bus bar 16b having the heat capacity increasing member 20 is fixed. That is, by the connection of the bolt 18, the heat capacity increasing member 20 and the second power-conducting bus bar 16b are fixed to the second connection portion 14b together.

[0067] <The third power-conducting bus bar 90 and the fourth power-conducting bus bar 92>

[0068] As also Figure 2 、 3 shown, the third power-conducting bus bar 90 is connected to the fuse 24 and the current sensor 26. Further, in the current sensor 26, the fourth power-conducting bus bar 92 is connected to the side opposite to the side where the third power-conducting bus bar 90 is connected. The third and fourth power-conducting bus bars 90, 92 are also formed by bending a metal plate into a predetermined shape by stamping or the like, similarly to the first and second power-conducting bus bars 16a, 16b.

[0069] The third energized bus bar 90 has rectangular fuse connection portions 94 and sensor connection portions 96 that extend horizontally at both end portions in the left-right direction. That is, in the third energized bus bar 90, the fuse connection portion 94 is provided on the left side, and the sensor connection portion 96 is provided on the right side. Bolt insertion holes that penetrate in the thickness direction (up-down direction) are formed in the fuse connection portion 94 and the sensor connection portion 96.

[0070] In Embodiment 1, the third energized bus bar 90 has a substantially barrel-shaped portion that extends in the front-rear direction and opens upward. The fuse connection portion 94 and the sensor connection portion 96 extend outward in the left-right direction from both left and right end portions of the upper opening portion of the substantially barrel-shaped portion. And, the bottom wall of the substantially barrel-shaped portion is a heat transfer portion 102 that is in thermal contact with the housing 22 (base member 28) during the assembly of the circuit structure 10.

[0071] The fourth energized bus bar 92 is configured in the same manner as the third energized bus bar 90. That is, the fourth energized bus bar 92 has a substantially barrel-shaped portion that extends in the front-rear direction and opens upward. The sensor connection portion 104 extends leftward from the left end portion of the upper opening portion of the substantially barrel-shaped portion, and the external connection portion 106 extends rightward from the right end portion. Bolt insertion holes that penetrate in the thickness direction (up-down direction) are formed in the sensor connection portion 104. Moreover, bolt insertion holes 110 that penetrate in the thickness direction (up-down direction) are formed in the external connection portion 106. And, the bottom wall of the substantially barrel-shaped portion is a heat transfer portion 112 that is in thermal contact with the housing 22 (base member 28) during the assembly of the circuit structure 10.

[0072] <bolt 18>

[0073] The relay 12 is fixed to the first and second energized bus bars 16a, 16b by bolts 18, 18. Specifically, the first and second connection portions 14a, 14b are aligned with the bolt insertion holes 82, 82 of the bolt connection portions 72, 72, and the bolts 18, 18 are inserted and connected. The bolts 18 can be made of well-known materials such as iron or stainless steel. In Embodiment 1, the bolts 18 are formed of iron. It should be noted that the linear expansion coefficient of iron is about 11 to 12 (×10 -6 / K) or so.

[0074] <heat dissipation sheets 114, 116>

[0075] When assembling the circuit structure 10, the heat transfer parts 74, 74, 102, 112 of the first to fourth power conducting bus bars 16a, 16b, 90, 92 are in thermal contact with the housing 22 (base member 28). In Embodiment 1, heat conducting sheets 114 as heat conducting members are received in the respective first receiving recesses 36 of the base member 28. And, the respective heat transfer parts 74, 74, 102, 112 are in thermal contact with the base member 28 via the heat conducting sheets 114.

[0076] In addition, in Embodiment 1, heat conducting sheets 116 are also received in the respective second receiving recesses 40 of the base member 28. And, when the circuit structure 10 is assembled to a vehicle, the base member 28 is in thermal contact with a heat sink 118 such as a body panel or a housing via the respective heat conducting sheets 116.

[0077] The heat conducting sheets 114, 116 are flat sheets extending in the vertical direction and are made of a synthetic resin having a higher thermal conductivity than air. Specifically, a silicone-based resin, a non-silicone-based acrylic resin, a ceramic-based resin, etc. can be used. More specifically, heat conductive silicone rubber etc. can be cited. The heat conducting sheets 114, 116 have flexibility and elasticity, and can elastically deform in a manner of changing the thickness dimension in response to a force applied in the vertical direction. Note that, in Embodiment 1, the heat conducting sheets 114, 116 are respectively used as heat conducting members provided on the upper and lower surfaces of the base member 28, but the two heat conducting members are not limited to this form, and heat conducting members of any shape can be adopted. For example, a heat dissipation gap filler or a heat conducting grease made of a silicone-based resin can also be used.

[0078] Particularly in Embodiment 1, the heat conducting sheet 114 is received in the first receiving recess 36 having a step 38, thereby positioning the heat conducting sheet 114 on the base member 28. And, the heat conducting sheet 116 is received in the second receiving recess 40 having a step 42, thereby positioning the heat conducting sheet 116 on the base member 28. In addition, each heat conducting sheet 114 is preferably clamped in a compressed state between the respective heat transfer parts 74, 74, 102, 112 and the base member 28 in the vertical direction. Each heat conducting sheet 114 can be in high-tight contact with the respective heat transfer parts 74, 74, 102, 112 and the base member 28 by being compressed. Thereby, each heat conducting sheet 114 can efficiently transfer heat from the heat transfer parts 74, 74, 102, 112 to the base member 28. Similarly, each heat conducting sheet 116 is preferably clamped in a compressed state between the base member 28 and the heat sink 118 in the vertical direction. The heat conducting sheet 116 can be in high-tight contact with the base member 28 and the heat sink 118 by being compressed. Thereby, the heat conducting sheet 116 can efficiently transfer heat from the base member 28 to the heat sink 118.

[0079] <Assembly process of the circuit structure 10>

[0080] Next, a specific example of the assembly process of the circuit structure 10 will be described. It should be noted that the assembly process of the circuit structure 10 is not limited to the following description.

[0081] First, prepare the cover member 30, the relay 12, the fuse 24, the current sensor 26, the first to fourth power-conducting busbars 16a, 16b, 90, 92, and the bolts 18. Then, place the relay 12 on the upper bottom wall 44 of the cover member 30 that is inverted up and down, insert the bolts through the legs 56, and connect them to a bolt fixing portion (not shown) provided on the cover member 30. Thereby, the cover member 30 and the relay 12 are fixed. Then, place the first and second power-conducting busbars 16a, 16b above the relay 12, and align the first and second connection portions 14a, 14b of the relay 12 with the bolt insertion holes 82, 82 of the first and second power-conducting busbars 16a, 16b. Next, insert the bolts 18, 18 through the first and second connection portions 14a, 14b and the bolt insertion holes 82, 82 to connect them. Thereby, the relay 12 and the first and second power-conducting busbars 16a, 16b are fixed.

[0082] Next, place the third power-conducting busbar 90 and the fourth power-conducting busbar 92 on the upper bottom wall 44 of the cover member 30, and then place the fuse 24 and the current sensor 26 above them. Thereby, the fuse connection portion 86 of the second power-conducting busbar 16b is overlapped with the connection portion 62 on the left side of the fuse 24. Also, the connection portion 62 on the right side of the fuse 24 is overlapped with the fuse connection portion 94 of the third power-conducting busbar 90. In addition, the sensor connection portion 96 of the third power-conducting busbar 90 is overlapped with the connection portion 68 on the left side of the current sensor 26. In addition, the connection portion 68 on the right side of the current sensor 26 is overlapped with the sensor connection portion 104 of the fourth power-conducting busbar 92. And insert bolts through the overlapped connection portions 62, 68, fuse connection portions 86, 94, sensor connection portions 96, 104, and connect them to a bolt fixing portion (not shown) provided on the cover member 30. Thereby, for the cover member 30, in addition to the relay 12 and the first and second power-conducting busbars 16a, 16b, the fuse 24, the current sensor 26, the third power-conducting busbar 90, and the fourth power-conducting busbar 92 are also fixed.

[0083] In addition, a base member 28, and heat conductive sheets 114 and 116 are prepared. Then, the heat conductive sheets 114 are received in the first receiving recesses 36 of the base member 28 and fixed by an adhesive or the like. Further, the heat conductive sheets 116 are received in the second receiving recesses 40 and fixed by an adhesive or the like. Then, the upper opening of the cover member 30 to which the relay 12, fuse 24, current sensor 26, and first to fourth power conducting bus bars 16a, 16b, 90, 92 are fixed is covered with the base member 28 to which the heat conductive sheets 114 and 116 are fixed, and the cover member 30 and the base member 28 are fixed to each other to form a housing 22. Then, the circuit structure 10 is completed by turning it upside down.

[0084] It should be noted that the order of fixing the relay 12, fuse 24, current sensor 26, and first to fourth power conducting bus bars 16a, 16b, 90, 92 to the cover member 30 is not limited to the above process. Further, the heat conductive sheets 114 provided between the first to fourth power conducting bus bars 16a, 16b, 90, 92 (heat transfer portions 74, 74, 102, 112) and the base member 28 may not be fixed to the base member 28 but to the lower surfaces of the heat transfer portions 74, 74, 102, 112. Similarly, the heat conductive sheets 116 provided on the lower surface of the base member 28 may not be fixed to the base member 28 but to the heat sink 118.

[0085] In the circuit structure 10 assembled in this way, the external connection portions 76 and 106 of the first power conducting bus bar 16a and the fourth power conducting bus bar 92 are exposed to the outside through the openings 48a and 48b of the cover member 30. Then, in a state where terminal portions at the ends of wires provided outside (not shown) are aligned with the bolt insertion holes 84 and 110 of the external connection portions 76 and 106, bolts (not shown) are inserted and connected, thereby electrically connecting the external wires to the first power conducting bus bar 16a and the fourth power conducting bus bar 92. Further, the circuit structure 10 is overlapped with the heat sink 118, and bolts (not shown) are inserted through bolt insertion holes 50 provided in the outer peripheral portion of the housing 22 (cover member 30) and connected, thereby fixing the circuit structure 10 to the heat sink 118. Thus, in the first embodiment, the heat conductive sheet 116 is compressed in the vertical direction between the circuit structure 10 and the heat sink 118.

[0086] In the circuit structure 10 of Embodiment 1, heat capacity increasing members 20, 20 are provided in the first and second power conducting busbars 16a, 16b, and the heat capacity increasing members 20, 20 are in thermal contact with a connection portion A connected to the first and second connection portions 14a, 14b of the relay 12. Specifically, the heat capacity increasing members 20 are formed by folding back and overlapping the upper end portions of the bolt connection portions 72, 72 in the first and second power conducting busbars 16a, 16b. Thus, at the connection portion A between the first and second power conducting busbars 16a, 16b and the first and second connection portions 14a, 14b of the relay 12, the first and second power conducting busbars 16a, 16b are each set to a thickness of two layers. Therefore, compared with the case where the first and second power conducting busbars are only set to a thickness of one layer, the heat capacity of the first and second power conducting busbars 16a, 16b can be increased. Thereby, the temperature rise of the first and second power conducting busbars 16a, 16b, and further the first and second connection portions 14a, 14b connected to the first and second power conducting busbars 16a, 16b can be suppressed, and the problem of heat generation during the flow of a large current or the like can be temporarily eliminated.

[0087] In addition, in Embodiment 1, the heat transfer portions 74, 74, 102, 112 of the first to fourth power conducting busbars 16a, 16b, 90, 92 are in thermal contact with the housing 22 (base member 28), respectively. Therefore, the heat of the relay 12, fuse 24, and current sensor 26 generated due to energization can be dissipated through the housing 22. Thereby, the problem of heat generation caused by the relay 12, fuse 24, and current sensor 26 can also be eliminated. Particularly in Embodiment 1, since the heat conductive sheets 114 are provided between the heat transfer portions 74, 74, 102, 112 and the base member 28, the heat transfer from the heat transfer portions 74, 74, 102, 112 to the base member 28 can be stably achieved. In addition, the heat conductive sheet 116 is provided on the lower surface of the base member 28, and the base member 28 is in thermal contact with the heat sink 118 via the heat conductive sheet 116. Thus, the heat generation of the relay 12, fuse 24, and current sensor 26 is also dissipated from the heat sink 118, and the improvement of the heat dissipation effect can be achieved.

[0088] In addition, in Embodiment 1, the upper end portions of the bolt connection portions 72, 72 of the first and second current-carrying busbars 16a, 16b constitute the heat capacity increasing members 20, 20, and bolt insertion holes 82, 82 are formed in the portions where the heat capacity increasing members 20, 20 are provided. Thus, by the connection of the bolts 18, 18, the heat capacity increasing members 20, 20 are also fixed together with the first and second current-carrying busbars 16a, 16b. That is, in Embodiment 1, since the first and second current-carrying busbars 16a, 16b and the heat capacity increasing members 20, 20 are formed integrally, an increase in the number of components can be avoided. Moreover, compared with the case where the heat capacity increasing members are separate from the first and second current-carrying busbars 16a, 16b, the assembly workability can be improved.

[0089] Particularly in Embodiment 1, the upper end portions of the bolt connection portions 72, 72 are folded back outward (forward) and overlap. Thus, compared with the case where the upper end portion of the bolt connection portion is folded back inward, the electrical path from the first and second connection portions 14a, 14b to the external connection portions 76 and the fuse connection portion 86 can be shortened. Thus, an increase in the conduction resistance associated with energization can be avoided. Moreover, the heat path from the first and second connection portions 14a, 14b to the heat transfer portions 74, 74 can also be shortened. Thus, the heat generated by the first and second connection portions 14a, 14b is dissipated more quickly through the heat transfer portions 74, 74.

[0090] In addition, holding portions 80, 80 for holding the overlapping state of the heat capacity increasing members 20, 20 (the upper end portions of the bolt connection portions 72, 72) are provided on the first and second current-carrying busbars 16a, 16b. Therefore, no gap is generated between the heat capacity increasing members 20, 20 and the bolt connection portions 72, 72, and in short, between the upper and lower end portions of the mutually overlapping bolt connection portions 72, 72, and the heat capacity at the position where the heat capacity increasing members 20, 20 are provided can be stably increased.

[0091] Note that the coefficient of linear expansion of the heat capacity increasing member 20 (the first and second current-carrying busbars 16a and 16b) is preferably set within a range of 1 / 3 to 3 times the coefficient of linear expansion of the bolts 18 and 18. Moreover, the coefficient of linear expansion of the heat capacity increasing member 20 (the first and second current-carrying busbars 16a and 16b) is more preferably set within a range of 1 / 2 to 2 times the coefficient of linear expansion of the bolts 18 and 18. In addition, the coefficient of linear expansion of the heat capacity increasing member 20 (the first and second current-carrying busbars 16a and 16b) is more preferably set within a range of 2 / 3 to 3 / 2 times the coefficient of linear expansion of the bolts 18 and 18. In addition, the coefficient of linear expansion of the heat capacity increasing member 20 (the first and second current-carrying busbars 16a and 16b) is most preferably equal to the coefficient of linear expansion of the bolts 18 and 18. By setting the coefficient of linear expansion of the heat capacity increasing member 20 (the first and second current-carrying busbars 16a and 16b) relatively close to 1 / 3 to 3 times the coefficient of linear expansion of the bolts 18 and 18, it is possible to suppress the loosening of the bolts 18 and 18 when the relay 12 generates heat. In addition, for example, when the first and second current-carrying busbars 16a and 16b are formed of copper and the bolts 18 and 18 are formed of iron, the coefficient of linear expansion of the heat capacity increasing members 20 and 20 is approximately 1.4 times the coefficient of linear expansion of the bolts 18 and 18.

[0092] In particular, by making the coefficient of linear expansion of the heat capacity increasing member 20 (the first and second current-carrying busbars 16a and 16b) equal to that of the bolts 18 and 18, that is, the heat capacity increasing member 20 (the first and second current-carrying busbars 16a and 16b) and the bolts 18 and 18 are made of the same material, it is possible to further suppress the loosening of the bolts 18 and 18 when the relay 12 generates heat.

[0093] <Embodiment 2>

[0094] Hereinafter, regarding Embodiment 2 of the present disclosure, reference is made to Figure 6 、 7 for description. The circuit structure 120 of Embodiment 2 has the same basic structure as the circuit structure 10 in the aforementioned Embodiment 1, but is different in that the heat capacity increasing members 122 and 122 are separated from the first and second current-carrying busbars 124a and 124b which are current-carrying members. In the following description, for components and parts that are substantially the same as those in the aforementioned embodiment, the same reference numerals as those in the aforementioned embodiment are marked in the drawings and detailed description is omitted. Note that in Figure 6 、 7 , the circuit structure 120 is shown in a state where the cover member 30 constituting the housing 22 is removed.

[0095] The heat capacity increasing component 122 in Embodiment 2 is in a rectangular block shape. A through hole 126 penetrating in the front-rear direction is formed in a substantially central portion of the heat capacity increasing component 122. The material of the heat capacity increasing component 122 is not limited as long as it can increase the heat capacity of the first and second power supply busbars 124a and 124b, and further the first and second connection portions 14a and 14b during assembly, but a metal with a high thermal conductivity is preferred. As the material of the heat capacity increasing component 122, it is more preferably made of iron, copper, aluminum, and their alloys, etc. In Embodiment 2, the heat capacity increasing component 122 is formed of a metal. It should be noted that the heat capacity increasing component 122 is preferably formed of a metal having a specific gravity lighter than that of copper and iron. This is because by using a metal with a light specific gravity, the influence of the vibration of the bolt 18 can be reduced.

[0096] The heat capacity increasing component 122 of Embodiment 2 is fixed to the relay 12 together with the first and second power supply busbars 124a and 124b by bolts 18. That is, the first and second connection portions 14a and 14b of the relay 12, the bolt insertion holes 82 of the first and second power supply busbars 124a and 124b, and the through hole 126 of the heat capacity increasing component 122 are aligned with each other in position. And, by inserting and connecting the bolts 18, the heat capacity increasing components 122, 122 are fixed to the relay 12 together with the first and second power supply busbars 124a and 124b. Thereby, the heat capacity increasing components 122, 122 are in thermal contact with the connection portion A between the first and second power supply busbars 124a and 124b and the first and second connection portions 14a and 14b. Particularly in Embodiment 2 as well, the heat capacity increasing component 122 overlaps the front surface 79, which is the surface on the opposite side of the contact surface 78 contacting the first and second connection portions 14a and 14b, at the bolt connection portion 72 of the first and second power supply busbars 124a and 124b. It should be noted that in the aforementioned Embodiment 1, the upper end portion of the bolt connection portion 72 is folded back, and the connection portion of the bolt 18 in the first and second power supply busbars 16a and 16b has a thickness dimension of two tensors, but the connection portion of the bolt 18 in the first and second power supply busbars 124a and 124b of Embodiment 2 has a thickness dimension of one tensor.

[0097] In the circuit structure 120 of Embodiment 2 as well, the heat capacity increasing component 122 is provided. Thereby, the heat capacity of the connection portion A between the first and second connection portions 14a and 14b of the relay 12 and the first and second power supply busbars 124a and 124b is increased, and thus the heat generation of the relay 12 can be suppressed. Therefore, the same effect as that of the aforementioned Embodiment 1 can be exerted.

[0098] Particularly in the circuit structure 120 of Embodiment 2, since the heat capacity increasing member 122 is separate from the first and second current-carrying bus bars 124a and 124b, a material that is more likely to increase the heat capacity compared to the first and second current-carrying bus bars 124a and 124b can also be used as the material of the heat capacity increasing member 122. Or by using the same material as the bolt 18 (for example, iron) as the material of the heat capacity increasing member 122, it is also possible to reduce the loosening of the bolt 18 when the relay 12 generates heat. As the shape of the heat capacity increasing member 122, it is not limited to a rectangular block shape, and it can be only a flat plate shape like a bus bar, or a shape that is likely to increase the heat capacity or a shape that can suppress the loosening of the bolt 18 when generating heat.

[0099] In addition, in Embodiment 2, the heat capacity increasing members 122 are also provided overlappingly on the front surface 79 of the bolt connection portions 72 of the first and second current-carrying bus bars 124a and 124b. Thus, the electrical path from the first and second connection portions 14a and 14b to the external connection portion 76 and the fuse connection portion 86, and the heat path to the heat transfer portions 74 and 74 are shortened, the increase in conduction resistance can be prevented, and rapid heat transfer can be achieved.

[0100] <Embodiment 3>

[0101] Hereinafter, regarding Embodiment 3 of the present disclosure, reference is made to Figure 8 、 9 for description. The circuit structure 130 of Embodiment 3 has the same basic structure as the circuit structure 120 in the aforementioned Embodiment 2, but is different in that metal caps 132 and 132 as heat capacity increasing members are assembled to the bolts 18 instead of the heat capacity increasing member 122. It should be noted that in Embodiment 3, the first and second current-carrying bus bars 124a and 124b having the same structure as in the aforementioned Embodiment 2 are used. Moreover, in Figure 8 、 9 , the circuit structure 130 is shown in a state where the cover member 30 constituting the housing 22 is removed.

[0102] That is, in Embodiment 3, the heat capacity increasing member is constituted by caps 132 assembled to the heads of the bolts 18. Therefore, a receiving recess 136 for receiving the head of the bolt 18 is formed in the cap 132. Thus, the cap 132 is in thermal contact with the connection portion A between the first and second current-carrying bus bars 124a and 124b and the first and second connection portions 14a and 14b via the bolt 18. In Embodiment 3, the cap 132 is formed of a metal having a high thermal conductivity. The cap 132 is preferably formed of, for example, iron, copper, aluminum, and their alloys. In short, the heat capacity increasing member is not limited to a form that is fixed to the heat generating member (relay 12) together with the current-carrying member (first and second current-carrying bus bars) through a connecting member (bolt 18).

[0103] After fixing the first and second energized busbars 124a and 124b to the first and second connection parts 14a and 14b of the relay 12 by bolts 18, the cap 132 is assembled to the head of the bolt 18. Alternatively, after assembling the cap 132 to the head of the bolt 18, the first and second energized busbars 124a and 124b can be fixed to the first and second connection parts 14a and 14b of the relay 12 by the bolts 18. A portion of the cap 132 on the outer peripheral side of the receiving recess 136 may or may not be in contact with the front surface 79 of the bolt connection part 72 in the first and second energized busbars 124a and 124b.

[0104] It should be noted that a heat-conducting grease 138 as a heat-conducting member is preferably provided between the inner surface of the receiving recess 136 of the cap 132 and the head of the bolt 18. Thereby, even if a gap is generated between the cap 132 and the bolt 18 due to, for example, manufacturing errors, heat transfer from the bolt 18 to the cap 132 can be stably achieved.

[0105] In the circuit structure 130 of Embodiment 3, a cap 132 that increases the heat capacity of the first and second connection parts 14a and 14b is provided on the bolts 18 that fix the relay 12 to the first and second energized busbars 124a and 124b. As a result, the temperature rise of the bolts 18 when the relay 12 generates heat, and further the first and second connection parts 14a and 14b, can be suppressed by the cap 132.

[0106] In particular, in Embodiment 3, since the cap 132 is made of metal, the heat capacity can be easily increased. Moreover, since the cap 132 is provided as a member different from the first and second energized busbars 124a and 124b and the bolts 18, a material that is easier to increase the heat capacity than the first and second energized busbars 124a and 124b and the bolts 18 can also be used as the material of the cap 132. It should be noted that by setting the linear expansion coefficients of the cap 132 and the bolt 18 to be close values, or by making the materials of the cap 132 and the bolt 18 the same, it is possible to make it difficult to generate a gap between the cap 132 and the bolt 18 when the relay 12 generates heat. It should be noted that the cap 132 is preferably formed of a metal having a specific gravity lighter than that of copper and iron. This is because by using a metal with a light specific gravity, the influence of the vibration of the bolt 18 can be reduced.

[0107] <Embodiment 4>

[0108] Hereinafter, regarding Embodiment 4 of the present disclosure, refer to Figure 10A description will be given. The circuit structure 140 of Embodiment 4 is the same as the circuit structure 10 of the foregoing Embodiment 1 in terms of the basic structure, but is different in that a synthetic resin cap 142 serving as a heat capacity increasing member is assembled to the bolt 18. That is, the cap 142 is in thermal contact with the connection portion A between the first and second energizing bus bars 16a and 16b and the first and second connection portions 14a and 14b via the bolt 18. It should be noted that in Figure 10 the circuit structure 140 is shown in a state where the lid member 30 constituting the housing 22 is removed.

[0109] In the circuit structure 140 of Embodiment 4, a cap 142 that increases the heat capacity of the first and second connection portions 14a and 14b is also assembled to the bolt 18 that fixes the relay 12 to the first and second energizing bus bars 16a and 16b. Therefore, in addition to the heat capacity increasing member 20 of the foregoing Embodiment 1, the suppression effect of the temperature rise based on the cap 142 is also added. In particular, in Embodiment 4, a synthetic resin cap 142 that is softer than metal is used, so that the head of the bolt 18 can be closely attached to the cap 142 with substantially no gap, and the contact area between the cap 142 and the head of the bolt 18 can be sufficiently ensured. Thereby, heat can be stably transferred from the bolt 18 to the cap 142. In addition, by using the synthetic resin cap 142, the electrical insulation of the head of the bolt 18 can also be ensured.

[0110] <Other Embodiments>

[0111] The technology described in this specification is not limited to the embodiments described in the above description and the drawings. For example, embodiments such as the following are also included in the technical scope of the technology described in this specification.

[0112] (1) In the foregoing embodiments, heat capacity increasing members 20, 122 and caps 132, 142 are provided at the connection portion A between the first and second connection portions 14a, 14b of the relay 12 as a heat generating component and the first and second energizing bus bars 16a, 124a, 16b, 124b, but it is not limited thereto. A heat capacity increasing member may also be provided at the connection portion between a fuse or a current sensor connection portion that generates heat due to energization and an energizing member (for example, the second to fourth energizing bus bars in the foregoing embodiment). That is, the heat generating component of the present disclosure may be a fuse or a current sensor instead of or in addition to the relay. It should be noted that it is not necessary to provide a plurality of heat generating components, and at least one may be provided.

[0113] (2) In the foregoing Embodiment 3, the cap 132 is used as the heat capacity increasing member instead of the heat capacity increasing member 20 of the foregoing Embodiment 1, but the cap 132 may also be used on the basis of the heat capacity increasing members 20, 122 in the foregoing Embodiments 1 and 2.

[0114] (3) The heat capacity increasing components 20, 122 and the caps 132, 142 of the foregoing embodiments may also have forms other than the foregoing embodiment 4, and at least two of them may be combined and used. That is, for example, the heat capacity increasing components as in the foregoing embodiments 1 and 2 may be combined and used at the connection portions between the first and second connection portions of the relay and the first and second energized bus bars. Alternatively, the heat capacity increasing components as in the foregoing embodiments 1 and 2 may be used at the connection portions between the first and second connection portions of the relay and the first and second energized bus bars, and the heat capacity increasing components as in the foregoing embodiments 3 and 4 may be provided at the connection portions between the connection portions of the fuse and the current sensor and the energized member.

[0115] (4) In the foregoing embodiments, the heat capacity increasing components 20, 122 and the caps 132, 142 as the heat capacity increasing components are respectively provided at the connection portions A between the first and second connection portions 14a, 14b of the relay 12 and the first and second energized bus bars 16a, 124a, 16b, 124b, but it is not limited thereto. The heat capacity increasing component may be provided at the connection portion between at least one of the connection portions and the energized member. It should be noted that the same applies to the case where the heat capacity increasing component is provided at the connection portion between the connection portion of the fuse and the current sensor and the energized member.

[0116] (5) A heat dissipation mechanism (for example, heat transfer portions 74, 102, 112, heat conducting sheets 114, 116, etc.) for dissipating heat from components that generate heat due to energization (for example, the relay 12, the fuse 24, and the current sensor 26 in the embodiments) is not essential. Even when a heat dissipation mechanism is provided, it is not limited to the configuration as in the foregoing embodiments, and a conventionally known heat dissipation mechanism may be adopted. For example, through holes may be provided in the housing (for example, the bottom wall of the base member), and the heat transfer portion may be in thermal contact with the heat sink directly or via a heat conducting member (for example, a heat conducting sheet).

[0117] (6) In the foregoing embodiments, the relay 12, the fuse 24, the current sensor 26, the first to fourth energized bus bars 16a, 124a, 16b, 124b, 90, 92 are all fixed to the cover member 30, but at least one of them may also be fixed to the base member.

[0118] (7) In the foregoing embodiments, the bolt 18 is exemplified as the connecting member, but it is not limited to the bolt, and a conventionally known connecting member such as a rivet that can connect the energized member and the connection portion may be adopted.

[0119] (8) The heat capacity increasing component of the present disclosure is not limited to the shape and material exemplified in the foregoing embodiments, and as long as the heat capacity is increased by the setting compared to the case of the energized member alone, the shape and material are not limited.

[0120] Description of Reference Numerals

[0121] 10 Circuit Structure (Embodiment 1)

[0122] 12 Relay (Heat-Generating Component)

[0123] 14 Connecting Portion

[0124] 14a First Connecting Portion

[0125] 14b Second Connecting Portion

[0126] 16 Energized Bus Bar (Energized Component)

[0127] 16a First Energized Bus Bar

[0128] 16b Second Energized Bus Bar

[0129] 18 Bolt (Connecting Component)

[0130] 20 Heat Capacity Increasing Component

[0131] 22 Housing

[0132] 24 Fuse

[0133] 26 Current Sensor

[0134] 28 Substrate Component

[0135] 30 Cover Component

[0136] 32 Bottom Wall

[0137] 34 Peripheral Wall

[0138] 36 First Receiving Recess

[0139] 38 Step

[0140] 40 Second Receiving Recess

[0141] 42 Step

[0142] 44 Upper Bottom Wall

[0143] 46 Peripheral Wall

[0144] 48a, 48b Opening

[0145] 50 Bolt Insertion Through-Hole

[0146] 52 Relay Body

[0147] 54 Insulating Plate

[0148] 56 Leg

[0149] 60 Fuse body

[0150] 62 Connection part

[0151] 66 Sensor body

[0152] 68 Connection part

[0153] 72 Bolt connection part

[0154] 74 Heat transfer part

[0155] 76 External connection part

[0156] 78 Contact surface

[0157] 79 Front surface (the side opposite to the contact surface)

[0158] 80 Holding part

[0159] 82, 84 Bolt insertion through-holes

[0160] 86 Fuse connection part

[0161] 88 Bolt insertion through-hole

[0162] 90 Third energized bus bar

[0163] 92 Fourth energized bus bar

[0164] 94 Fuse connection part

[0165] 96 Sensor connection part

[0166] 102 Heat transfer part

[0167] 104 Sensor connection part

[0168] 106 External connection part

[0169] 110 Bolt insertion through-hole

[0170] 112 Heat transfer part

[0171] 114 Heat conducting sheet (heat conducting member)

[0172] 116 Heat conducting sheet

[0173] 118 Heat sink

[0174] 120 Circuit structure body (Embodiment 2)

[0175] 122 Heat capacity increasing component

[0176] 124a First energized bus bar (energized member)

[0177] 124b Second energized bus bar (energized component)

[0178] 126 Through hole

[0179] 130 Circuit structure body (Embodiment 3)

[0180] 132 Cap (heat capacity increasing component)

[0181] 136 Receiving recess

[0182] 138 Thermal conductive grease (thermal conductive component)

[0183] 140 Circuit structure body (Embodiment 4)

[0184] 142 Cap (heat capacity increasing component)

[0185] A Connection part.

Claims

1. A circuit structure, comprising: a heating component that generates heat when energized; a power-on member connected to a connection portion of the heating component; a connecting member that connects the power-on member to the connection portion; and a heat capacity increasing component that makes thermal contact with a connection portion between the power-on member and the connection portion to increase the heat capacity of the connection portion of the heating component, wherein the heat capacity increasing component is made of metal, the heat capacity increasing component is connected to the connection portion together with the power-on member by the connecting member, the heat capacity increasing component is formed by an end portion of the power-on member, and is folded back and overlaps a surface on the opposite side of a contact surface of the power-on member that contacts the connection portion.

2. A circuit structure, comprising: a heating component that generates heat when energized; a power-on member connected to a connection portion of the heating component; a connecting member that connects the power-on member to the connection portion; and a heat capacity increasing component that makes thermal contact with a connection portion between the power-on member and the connection portion to increase the heat capacity of the connection portion of the heating component, wherein the power-on member has a connection portion connected to the connection portion and a heat transfer portion extending from the connection portion, the heat capacity increasing component overlaps a surface on the opposite side of a contact surface of the power-on member that contacts the connection portion, in a state where the heating component is disposed on the heat transfer portion, the connection portion of the heating component is located on a side surface, the connection portion protrudes upward from the heat transfer portion and has a bolt insertion hole that penetrates the contact surface and the heat capacity increasing component and is long in the vertical direction, the connection portion is connected to the connection portion by a bolt inserted through the bolt insertion hole.

3. The circuit structure according to claim 1 or 2, wherein, the circuit structure further includes a heat conducting member and a housing, and the power-on member makes thermal contact with the housing via the heat conducting member.

4. The circuit structure according to claim 1 or 2, wherein, a holding portion is provided on the power-on member, and the holding portion holds an overlapping state of an end portion of the power-on member and the surface on the opposite side.

5. The circuit structure according to claim 1 or 2, wherein, a linear expansion coefficient of the heat capacity increasing component is 1 / 3 times to 3 times that of the connecting member.

6. The circuit structure according to claim 1 or 2, wherein, the heat capacity increasing component and the connecting member are made of the same material.

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