JP5203416B2 - Mounting structure for in-vehicle circuit unit and electrical junction box - Google Patents

Description

The present invention relates to power vehicle circuit unit used in the distributor or the like and the mounting structure of the electric connection box in-vehicle circuit unit is incorporated for performing power distribution to vehicle equipment such as a power source mounted on a vehicle is there.

  Conventionally, as a means for distributing electric power from a common in-vehicle power source to each in-vehicle device, a circuit unit in which a power distribution circuit is configured by laminating a plurality of bus bar boards and a fuse or a relay switch is incorporated in the circuit unit is generally known. ing. Furthermore, in recent years, in order to realize the miniaturization of such a circuit unit, it has been studied to bond a bus bar and a control circuit body or introduce a semiconductor switching element such as an FET instead of the relay.

  By the way, in such a circuit unit, heat is likely to be generated due to a relatively large current flowing through the bus bar, and in particular, since the amount of heat generated by the switching elements such as the FET and the relay switch is large, how to efficiently dissipate the heat. Is a big issue.

  As a solution to this problem, Patent Document 1 discloses a control box in which a circuit pattern including electrical and electronic components is provided on a heat dissipation board. In this control box, the heat dissipation board is formed in a flat plate shape, and a bolt is passed through a mounting hole provided on an edge of one side of the control box to fasten it to the vehicle body. The control box is mounted in a state where the entire area is in contact with the body.

JP-A-5-343871 (FIGS. 1 and 2)

  The control box described in Patent Document 1 is designed so that the entire heat dissipation board is flat and basically the entire outer surface of the heat dissipation board contacts the body of the vehicle. Since the outer surface of the heat dissipation board has irregularities, warpage, deflection, etc., this causes a minute gap to be easily scattered between the outer surface of the heat dissipation board and the surface of the body, and water is present in the minute gap. There is a risk of inconvenience such as accumulation and rusting. In particular, at the part away from the part directly fixed to the body by the bolt, the outer surface of the heat radiating board is likely to float slightly from the body. May adversely affect the normal operation of the camera or cause abnormal noise.

  As a means for eliminating such inconvenience due to vibration, it is conceivable to provide bolt insertion holes uniformly around the entire periphery of the heat radiating substrate, and directly tighten the entire periphery with bolts. Even if the structure is adopted, an effective reduction of the minute gap cannot be expected. In addition, the space for mounting the control box in the vehicle body is limited. For example, when the control box is installed in a narrow engine room, it is practically difficult to fasten the peripheral edge of the heat dissipation board to the body side wall over the entire circumference. It is.

In view of such circumstances, the present invention effectively reduces the minute gap generated between the heat radiating member and the body, and avoids the occurrence of shocks and abnormal noise accompanying the vibration of the vehicle. and to provide a vehicle circuit unit and the mounting structure of the electric connection box can be ensured Do cooling performance.

As a means for solving the problem, the present invention is a circuit constituting the power circuit, the case body surrounds the circuit body, and said circuit element is an inner surface which is fixed by heat conduction ready the a vehicle circuit unit provided with a heat dissipation member having an outer surface that is heat radiating surface by exposing to the outside on the opposite side, the electrical connection box and the vehicle in which the vehicle circuit unit is incorporated with other circuit body a structure attached to the vehicle circuit unit, the outer surface of the heat radiating member is incorporated before Symbol electrical junction box in a state exposed to the outside of the electrical connection box, said electrical connection box, the integrated the outside surface opposite the direction ku state inner surface and the circuit member and the case body is arranged with countercurrent ku body and the body of the vehicle of the heat radiating member of the in-vehicle circuit unit, said electrical connection the box's As a posture facing with a gap between the exposed outer surface and the body in part, in which is attached taken to the body together with the vehicle circuit unit.

According to this configuration, although the in- vehicle circuit unit is incorporated in a common electrical junction box together with other circuit bodies, the outer surface of the heat dissipation member exposed to the outside of the electrical junction box and the body The in-vehicle circuit unit and the electrical connection box are attached to the body in a posture facing each other with a gap therebetween. Thereby, in the in-vehicle circuit unit in spite of being incorporated in the electric junction box, there is no possibility that minute gaps are scattered between the outer surface of the heat dissipation member and the body, and the outer surface of the heat dissipation member Even if the body is separated, effective heat transfer by radiation from the heat radiating member to the body can be realized and a good cooling effect can be obtained.

From such a viewpoint of heat transfer, the in-vehicle circuit unit and the electrical junction box are attached to the body so that the body and the outer surface of the heat dissipation member of the in-vehicle circuit unit face each other in a substantially parallel posture. It is more preferable.

  The heat dissipating member may have its entire outer surface separated from the body, but the heat dissipating member has a mounting portion fixed to the body in contact with the vehicle body, and the mounting portion. If the outer surface of the heat dissipating member excluding the mounting portion is opposed to the body with a gap in a state where it is fixed to the body, the cooling performance can be further enhanced by heat conduction from the mounting portion to the body. it can. In addition, since the contact between the mounting portion and the body is local, unlike the conventional case where the entire outer surface of the heat radiating member is in contact with the body, there is a minute gap between the outer surface of the heat radiating member and the body. There is almost no risk of being scattered. Further, even if the mounting portion is provided not on the entire circumference of the heat radiating member but on a part thereof, it is possible to avoid the occurrence of noise and impact due to the heat radiating member repeatedly hitting the body during vehicle vibration.

The specific mounting positions of the on-vehicle circuit unit and the electrical junction box are not limited, but when the mounting is performed particularly in a narrow space, for example, the mounting portion of the on-vehicle circuit unit contacts the inner surface of the engine room. This is particularly effective when fixed in a state.

In this case, if the vehicle circuit unit and electric connection box in a posture in which the attachment portion is oriented upward for attachment to the body, the circuit unit and the electrical connection box of mounting operation in the engine room of vehicle equipment are concentrated Can be easily performed from above.

  In general, the body of a vehicle has a hollow structure (double structure) on the side wall, and heat dissipation to the outside is relatively low, whereas the bottom wall has high heat dissipation. If the mounting portion is fixed to the bottom surface in contact with the bottom surface of the room, higher cooling performance can be obtained.

  As a specific connection structure between the attachment portion and the vehicle body, for example, a bolt insertion hole is provided in the attachment portion, and the attachment portion is attached to the vehicle body by a metal bolt inserted into the bolt insertion hole. What is fastened is preferred. According to this structure, heat transfer from the heat radiating member to the body can be made more effective through the metal bolts.

  In the present invention, it is also effective to make the outer surface of the heat radiating member face the battery in the engine room instead of facing the vehicle body. Since the temperature of the battery is considerably lower than the temperature in the engine room, if the outer surface of the heat radiating member faces the battery, the heat radiating member can exhibit good cooling performance.

State also, the electric connection box, have a mounting piece which is fixed to the body of the vehicle, said heat radiating member, the mounting piece of the electrical connection box is in contact with the body when secured to the body of the vehicle The outer surface exposed from the electrical junction box faces the body, and the inner surface on which the circuit body and the case body are disposed is opposite to the body. The mounting portion so that the outer surface exposed to the outside of the electrical junction box of the heat radiating member excluding the mounting portion faces the body with a gap in a state where the mounting portion is fixed to the body. Is provided with a step between the surface in contact with the body and the outer surface of the heat radiating member.

If fixing the attachment piece of the electrical connection box to the body mounting portion of the vehicle circuit unit is fixed to the body of the vehicle, despite the state of being incorporated in the electrical connection box together with other circuit member, In the in-vehicle circuit unit incorporated in the electrical junction box, a structure can be obtained in which the body and the outer surface of the heat radiating member other than the attachment portion are opposed to each other with a gap.

  Here, if the surface of the mounting portion that contacts the body and the outer surface of the heat radiating member are substantially parallel, the outer surface of the heat radiating member and the body can be opposed in a substantially parallel posture. .

  Although the specific shape of the heat radiating member is not limited, the heat radiating member is formed of a metal plate, and the attachment portion is extended from the edge of the metal plate with the stepped portion. A good gap can be secured between the outer surface of the member and the body.

As described above, according to the present invention , in a vehicle-mounted circuit unit, a minute gap generated between the heat dissipation member and the body is effectively used in spite of being incorporated in an electrical junction box together with other circuit bodies. And effective heat transfer by radiation from the heat radiating member to the body can be obtained and a good cooling effect can be obtained while avoiding the occurrence of shocks and abnormal noise caused by vehicle vibration. .

It is a perspective view which shows the circuit unit to which this invention was applied. It is sectional drawing of the said circuit unit. It is a perspective view of the electrical junction box in which the circuit unit was incorporated. It is a top view which shows the state in which the said electrical-connection box was installed in the engine room. It is a cross-sectional front view which shows the structure in the said engine room. It is a cross-sectional front view which shows the example which gave the level | step difference to the inner wall in the said engine room. It is a sectional front view showing the example in which the lower part of the inner wall inclines in the engine room. It is a cross-sectional front view which shows the example which the whole inner wall inclines in the said engine room. It is a cross-sectional front view which shows the example which abbreviate | omitted the attachment part of the heat sink of the circuit unit installed in the said engine room. (A) is a side view which shows the example of the circuit unit attached to the upper surface of a wheel house, (b) is a cross-sectional front view which shows the attachment state. It is a cross-sectional front view which shows the example which made the heat sink outer surface of the circuit unit face the battery in the engine room.

  A preferred embodiment of the present invention will be described with reference to the drawings. In addition, although embodiment shown here applies this invention to the circuit unit U which comprises the power distribution circuit which distributes electric power from the common power supply to several vehicle equipment, this invention is not restricted to this, The present invention can be widely applied to circuit units constituting various circuits.

  The circuit unit U shown in FIGS. 1 and 2 includes a heat radiating plate (heat radiating member) 10, a case body 20, and a sheet-like circuit body 30, and the circuit body 30 includes a substrate mounting element 40 and a connector 50. , 60 are implemented. A cover 70 that covers the circuit body 30 is mounted on the connectors 50 and 60.

  The heat radiating plate 10 is made of a metal plate having excellent heat conductivity such as an aluminum alloy, and its outer side surface (lower surface in FIGS. 1 and 2) 11B serves as a heat radiating surface, while the inner side surface (FIGS. 1 and 2). 2, the case main body 20 and the circuit body 30 are bonded to each other in an insulating state via a common adhesive sheet 18.

  The case body 20 is formed of an insulating material such as synthetic resin, and has a frame shape surrounding the circuit body 30 in the illustrated example.

  The circuit body 30 has both a power distribution circuit for distributing power from a vehicle-mounted power source to a plurality of loads, and a control circuit for controlling on / off of the power circuit. The power circuit is constituted by a bus bar layer 32 in which a plurality of bus bars are arranged on the same plane, and a control circuit is incorporated in a thin printed circuit board 34, and each bus bar is formed on the lower surface of the printed circuit board 34. 32 is adhered in an insulating state via an adhesive layer 36.

  In the present invention, regardless of the specific configuration of the circuit body, for example, a bus bar and an insulating plate may be alternately stacked over a plurality of layers like a conventional bus bar substrate.

  In addition to the relay switch element shown in the figure, the board mounted element 40 includes a semiconductor element such as an FET, a resistance element and other electric circuit elements, and the like on the bus bar layer 32 and the printed circuit board 34 of the circuit body 30. To be implemented as appropriate.

  The connector 50 is for inputting power to the circuit body 30, and the connector 60 outputs power from the circuit body 30 to each in-vehicle device, and the circuit body 30 and various sensors and other control units For transmitting and receiving signals between the two. Each of the connectors 50 and 60 includes a connector terminal including board connection terminals 52 and 62 and housings 54 and 64 for holding these terminals. The board connection terminals 52 and 62 penetrate the circuit body 30. In this state, the circuit body 30 is connected by soldering or the like.

  In the illustrated example, through holes 18a, 18b, and 18c are provided in the adhesive sheet 18 in order to avoid contact between the board connection terminals 52 and 62 protruding from the lower surface of the circuit body 30 and the adhesive sheet 18 and the heat sink 10. While being provided, the heat sink 10 is formed with recesses 16A, 16B, and 16C. These recesses 16A, 16B, and 16C are formed by pressing a midway portion of the heat sink 10 downward by pressing, and the outer surface 11B of the heat sink 10 is locally located at the position where the recesses 16A, 16B, and 16C are formed. It is in a state protruding.

  Next, the structure for attaching this circuit unit U to the vehicle body will be described.

  The attachment portion 12 is extended from a specific position of the edge of the heat radiating plate 10, and the outer surface (the lower surface in FIGS. 1 and 2) of the attachment portion 12 is a contact surface 13 that contacts the body surface S. The mounting portion 12 is provided with a bolt insertion hole 14 that passes through the mounting portion 12 in the thickness direction.

  Further, a mounting portion cover 22 is formed on the side of the case body 20 so as to be superimposed on the vehicle body mounting portion 12 of the heat radiating plate, and the bolt insertion hole 24 that matches the bolt insertion hole 14 is formed in the mounting portion cover 22. Is provided. Then, when the bolts are inserted into the bolt insertion holes 14 and 24 in a state where the contact surface 13 is in contact with the body surface S, the mounting portion 12 is fastened to the body using the bolts. Yes.

  Further, as a feature of the circuit unit U, the base portion of the mounting portion 12 extends obliquely, and thereby, the contact surface 13 of the mounting portion 12 and the outer surface 11B of the heat sink 10 are substantially parallel. However, a step is provided between both surfaces 13 and 11B.

  The contact surface 13 of the mounting portion 12 of the circuit unit U is brought into contact with an appropriate part of the body surface S, and is fastened to the body by bolts inserted through the bolt insertion holes 14 and 24 of the mounting portion 12 and the mounting portion cover 22. Thus, for example, when the body surface S is a flat surface, the entire area of the heat sink outer surface 11B excluding the mounting portion 12 in the circuit unit U has a gap having a dimension corresponding to the dimension of the step with respect to the body surface S. In this case, they face each other in a substantially parallel posture. Thus, by reliably separating the heat sink outer surface 11B from the body surface S, it is possible to prevent rusting due to retention of water droplets.

  Here, the dimension of the gap may be set as appropriate, but its minimum value (in the example shown in the figure, the dimension of the gap formed between the outer surface 11B and the body surface S at the formation site of the recesses 16A to 16C) d1. Is preferably set to 3 mm or more. If this clearance is secured, it is ensured that the heat sink outer surface 11B (especially the outer surface 11B at the end opposite to the mounting portion 12) repeatedly contacts the body due to vehicle vibration or the like. Therefore, it is possible to prevent the occurrence of abnormal noise and impact due to such contact.

  Even if the outer surface 11B and the body surface S are separated from each other, it is possible to effectively transfer heat to the body by radiation from the outer surface 11B to ensure a high cooling effect. Here, the emissivity of the aluminum plate or the iron plate that is the base material of the body or the heat radiating plate 10 is about 0.2, but it is possible to easily obtain the emissivity of about 0.7 by coating this. Is possible. Therefore, it is more preferable that the heat radiating plate outer surface 11B and the body surface S opposed thereto have a radiation rate of 0.7 or more and 1.0 or less.

  On the other hand, the maximum value of the gap size (in the example shown in the figure, the size of the gap formed between the outer surface 11B and the body surface S in the portion other than the recesses 16A to 16C) d2 is preferably set to 20 mm or less. . Thereby, the circuit unit U and a body can be made to adjoin and the attachment space can be restrained small.

  When the body surface S is not a flat surface, for example, when it is a curved surface or an uneven surface, the undulation is expected, and finally the gap dimension between the body surface S and the heat sink outer surface 11B is determined. What is necessary is just to design the level | step difference dimension of the said outer surface 11B and the contact surface 13 so that it may be settled in the said range.

  The circuit unit U may be attached to the body of the vehicle alone, or may be attached in a state of being incorporated in a common electric junction box together with other circuit bodies. An example is shown in FIG.

  The illustrated electrical connection box 90 includes a lower case 92 and an upper case (not shown), and the circuit unit U and another circuit body 94 are incorporated in the lower case 92. The circuit unit U is incorporated in the lower case 92 so that the outer surface 11B of the heat sink 10 is exposed to the outside from the side wall of the lower case 92, and the mounting portion 12 and the mounting portion cover 22 are connected to the lower case 92 from the side wall. It is in a state protruding to the side. In addition, the lower case 92 is provided with mounting pieces 95 and 96 separately from the mounting portion 12, and the mounting pieces 95 and 96 are also provided with bolt insertion holes 95a and 96a.

  4 and 5 show an example in which the electric junction box 90 is mounted in the engine room 100 below the bonnet 104. FIG. A radiator fan 105 is installed at the front of the illustrated engine room 100, an engine 106 is installed at the center, and an air cleaner 107 and a battery 108 are installed on the sides of the engine 106. The electrical junction box 90 is installed vertically in a narrow space between the battery 108 and the inner wall of the engine room.

  Specifically, the reinforcement 102 extends forward and backward on both the left and right sides of the engine room 100, and the attachment piece 96 of the lower case 90 is bolted on the engine room bottom wall 102 a formed by the reinforcement 102. The metal bolt 104 inserted into the insertion hole 96a is fastened, and the mounting portion 12 of the circuit unit U and the mounting piece 95 of the lower case 90 are attached to the engine room inner wall (side wall) 102b formed by the reinforcement 102. It is fastened by a metal bolt 104 inserted through the bolt insertion holes 14, 95a. Specifically, bolt insertion holes are provided at appropriate positions on the engine room bottom wall 102a and the inner wall 102b, and a nut 103 is fixed to the back side thereof by welding or the like. The nut 103 is connected to the bolt insertion holes 14, 95a. When the inserted metal bolt 104 is screwed, the attachment pieces 95 and 96 are fastened to the engine room bottom wall 102a and the inner wall 102b.

  In this structure, the heat radiating plate outer surface 11B faces the engine room inner wall 102b with a substantially constant gap, and the heat of the heat radiating plate 10 is not only radiated, but also through the contact surface 13 and the metal bolt 104. It is effectively transmitted to the reinforcement 102 side by conduction. Further, since the attachment portion 12 is attached to the inner wall 12 in a posture facing upward, the attachment operation can be easily performed from above the engine room 100.

  Instead of providing a step between the contact surface 13 of the mounting portion 12 and the outer surface 11B of the heat radiating plate 10, a step portion 102c is formed on the inner wall 102b of the engine room as shown in FIG. Even if a step is provided between the portion to which 12 is fixed and the lower portion, the heat sink outer surface 11B and the engine room inner wall 102b can be opposed to each other with a gap corresponding to the step. It is.

  Further, the entire area of the heat sink outer surface 11B excluding the mounting portion 12 is not limited to being substantially parallel to the engine room inner wall 102b. For example, as shown in FIGS. A portion facing the lower portion of the side surface 11B or a portion facing the entire surface of the heat sink outer surface 11B may be an inclined surface 102d inclined with respect to the outer surface 11B.

  Further, as shown in FIG. 9, the mounting portion 12 may be omitted so that the entire surface of the heat sink outer surface 11B faces the engine room inner wall 102b. In this case, heat conduction from the heat radiating plate 10 to the engine room inner wall 102b does not occur, but the heat radiating member 10 can be cooled by heat transfer by radiation.

  In the present invention, the portion where the heat radiating plate outer surface 11B is opposed and the portion where the mounting portion 12 is fixed are not limited to the engine room inner wall 102b as described above, but the bottom surface of the engine room 100, for example, a wheel house 120 as shown in FIG. You may make it make the heat sink outer surface 11B oppose the upper surface of the said wheel house 120 by making the attachment part 12 contact and fix to the upper surface of this.

  In general, the side wall of the vehicle body (for example, the fender portion that surrounds the engine room 100 from the left and right sides) has a hollow double structure, and the heat dissipation to the outside is often relatively low. Since the body bottom wall including the wheel house 120 is composed of a single metal plate and has a relatively high heat dissipation structure, the heat sink outer surface 11B should be opposed to the bottom of the body. Is effective in obtaining good cooling performance.

  Also in this case, for example, an attachment portion may be extended from the case of the electrical connection box 90 in which the circuit unit U is incorporated, and the attachment portion may be fixed to the wheel house 120, the engine room side wall, or the like.

  Further, instead of the engine room inner wall 102b and the wheel house 120, it is also effective to arrange the circuit unit U so that the heat sink outer surface 11B faces the battery 108 in the engine room 100 as shown in FIG. It is. In general, since the battery 108 contains the decomposition solution and the surface thereof can be maintained at a low temperature regardless of the temperature rise in the engine room, the battery 108 can be improved by making the outer surface 11B of the heat sink 10 face the surface of the battery 108. Cooling performance can be exhibited.

  The heat radiating member according to the present invention is not limited to a plate-like member such as the heat radiating plate 10, and may be, for example, a block-like member. However, if the heat dissipating member is composed of a metal plate like the illustrated heat dissipating plate 10 and the attachment portion 12 is extended from the edge of the metal plate with a step, the heat dissipating member having a simple structure and high heat dissipating performance. It is possible to build

10 Heat dissipation plate (heat dissipation member)
11A Heat sink inner surface 11B Heat sink outer surface 12 Mounting portion 13 Contact surface 14 Bolt insertion hole 30 Circuit body 90 Electrical junction box 100 Engine room 102b Engine room inner wall 104 Metal bolt 108 Battery U Circuit unit S Body surface d1, d2 Gap Size

Claims (12)

A circuit body constituting the power circuit, a case body surrounding the circuit body , and an inner surface to which the circuit body is fixed in a thermally conductive state and the outside thereof are exposed to the outside to be a heat radiating surface. a vehicle circuit unit provided with a heat dissipation member having an outer surface, an electrical connection box in which the vehicle circuit unit is incorporated together with other circuit member is a structure attached to the vehicle,
The vehicle circuit unit is incorporated before Symbol electrical junction box in a state where the outer surface of the heat dissipation member is exposed to the outside of the electrical junction box,
The electrical connection box, opposite the inner surface which the outer surface and the circuit member and the case body together toward Ward the body of the vehicle is disposed of the heat radiating member is said body of said integrated vehicle circuit unit countercurrently ku state, so that the posture in which opposed with a gap between the outer surface and the body exposed to the outside of the electrical junction box, it together with the vehicle circuit unit is attached taken to the body A mounting structure for an on-vehicle circuit unit and an electrical junction box . 2. The mounting structure for an in-vehicle circuit unit and an electrical junction box according to claim 1, wherein the in-vehicle circuit unit is arranged so that the body and the outer surface of the heat radiating member of the in-vehicle circuit unit face each other in a substantially parallel posture. A mounting structure for an on-vehicle circuit unit and an electrical junction box , characterized by being mounted on a body. 3. The mounting structure for an on-vehicle circuit unit and an electrical junction box according to claim 1 or 2, wherein the heat dissipating member has a mounting portion fixed to the body in contact with the body of the vehicle, and the mounting. A mounting structure for an on-vehicle circuit unit and an electrical junction box , wherein an outer surface of the heat radiating member excluding the mounting portion is opposed to the body with a gap in a state where the portion is fixed to the body. 4. A mounting structure for an in-vehicle circuit unit and an electrical junction box according to claim 3, wherein the mounting portion of the in-vehicle circuit unit is fixed to the inner side surface in contact with the inner side surface of the engine room. Mounting structure for in-vehicle circuit unit and electrical junction box . 5. The on-vehicle circuit unit and the electrical junction box mounting structure according to claim 3, wherein the mounting portion is fixed to the bottom surface in contact with the bottom surface of the engine room, and Electric junction box mounting structure. The mounting structure of the on-vehicle circuit unit and the electrical junction box according to any one of claims 3 to 5, wherein the mounting portion is provided with a bolt insertion hole, and the mounting portion is formed by a metal bolt inserted into the bolt insertion hole. A structure for mounting an on-vehicle circuit unit and an electrical junction box , wherein the mounting structure is fastened to a vehicle body. The mounting structure of the on-vehicle circuit unit and the electrical junction box according to any one of claims 3 to 6, wherein an outer surface of the heat radiating member excluding the mounting portion in a state where the mounting portion is fixed to the body is spaced from the body. Mounting the vehicle-mounted circuit unit and the electrical junction box , wherein a step is provided between a surface of the mounting portion that contacts the body and an outer surface of the heat dissipation member so as to face each other Construction. 8. The mounting structure for an in-vehicle circuit unit and an electrical junction box according to claim 3, wherein the in-vehicle circuit unit is attached to the body in a posture in which the mounting portion faces upward. Mounting structure for in-vehicle circuit unit and electrical junction box . In-vehicle circuit unit and the mounting structure for an electric junction box according to claim 1 or 2, wherein the electrical connection box, have a mounting piece which is fixed to the body of the vehicle, the heat dissipation member, the electrical connection box And a mounting portion fixed to the body in contact with the body when the mounting piece is fixed to the body of the vehicle, and an outer surface exposed from the electrical junction box faces the body and Exposed to the outside of the electrical junction box of the heat dissipation member excluding the mounting portion in a state where the mounting portion is fixed to the body so that the inner surface on which the circuit body and the case main body are disposed faces the opposite side of the body. The mounting portion is provided with a step between the surface contacting the body and the outer surface of the heat radiating member so that the outer surface faces the body with a gap. Circuit unit And the mounting structure of the electrical junction box. The mounting structure of the on-vehicle circuit unit and the electrical junction box according to claim 9, wherein a surface of the mounting portion of the heat dissipation member that contacts the body and an outer surface of the heat dissipation member are substantially parallel. Mounting structure for in-vehicle circuit unit and electrical junction box . The mounting structure of the on-vehicle circuit unit and the electrical junction box according to claim 9 or 10 , wherein the heat radiating member is formed of a metal plate, and the mounting portion is extended from the edge of the metal plate with the step. A mounting structure for an on-vehicle circuit unit and an electrical junction box . A circuit body constituting the power circuit, a case body surrounding the circuit body , and an inner surface to which the circuit body is fixed in a thermally conductive state and the outside thereof are exposed to the outside to be a heat radiating surface. a vehicle circuit unit provided with a heat dissipation member having an outer surface, an electrical connection box in which the vehicle circuit unit is incorporated together with other circuit member is a structure attached to the vehicle,
The vehicle circuit unit is incorporated before Symbol electrical junction box in a state where the outer surface of the heat dissipation member is exposed to the outside of the electrical junction box,
The electrical connection box, the inner surface of the outer surface and the circuit member and the case body together toward ku surface of the battery in the engine compartment of the vehicle is disposed of the heat radiating member of the built-in-vehicle circuit unit the opposite side of the battery in a direction Ku state, so that the posture facing with a gap between the electrical connection box external to the exposed outer surface and the battery surface, the together with the vehicle circuit units automotive circuit unit and mounting structure for an electric connection box, characterized in that attached taken into the engine room.

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