JP3434710B2 - Heat dissipation structure of electrical junction box - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipating structure for an electric junction box, and more particularly, to a connection between terminals such as a wire harness and electronic / electrical functional parts mounted on an automobile or the like. The present invention relates to a heat dissipation structure of an electrical junction box that performs branching. 2. Description of the Related Art As shown in FIG. 4, a conventional electric connection box 1 mounted on an automobile or the like and connected or branched between terminals such as wire harnesses and electronic / electrical functional parts has a fuse as shown in FIG. An upper case 6 having a component mounting portion 4 on which the electronic / electrical functional component 2 such as a power supply and a relay is mounted, and a lower case 8 assembled to a lower portion of the upper case 6 define an accommodation space. A plurality of insulating substrates 10 are provided in the accommodation space. The component mounting unit 4 includes a connection terminal 2 a of the electronic / electrical functional component 2 mounted on the component mounting unit 4.
Has a structure facing the upper case 6. A bus bar 12 formed in a predetermined shape by punching and bending a metal plate is arranged on each of the insulating substrates 10 housed in the case.
By laminating these insulating substrates 10 to form a wiring board assembly, a desired circuit body is formed. The connection terminal 2a of the electronic / electric component 2 facing the inside of the upper case 6 from the component mounting portion 4 and the male tab terminal 1 of the bus bar 12
2a generally means these connection terminals 2a and male tab terminals 1
A terminal fitting portion 14a into which 2a fits is electrically connected via relay terminals 14 provided at both ends. Meanwhile, in recent automobiles and the like, the number of electronic / electric devices and electric control units mounted on the vehicle has increased, and the integration and density of electronic / electric components have been increased. Electronic and electrical components 2 that generate large amounts of heat and generate large amounts of heat, such as relays and power transistors
Is increasing. For this reason, in the recent electric junction box 1, it is desired to provide a heat radiating means for preventing the bus bar from being excessively high temperature due to heat conduction from the electronic / electric component 2 generating a large amount of heat or a rise in temperature due to energization of the bus bar itself. As disclosed in, for example, Japanese Patent Application Laid-Open No. 5-15036, a heat radiating unit equipped with a heat pipe for cooling between the insulating substrate 10 and the lower case 8 has also been proposed. [0005] However, the heat dissipating mechanism provided with the heat pipe disclosed in the above-mentioned Japanese Patent Application Laid-Open No. HEI 5-15036 has a complicated structure, which leads to an increase in cost, and at the same time, causes a problem in the electric connection box 1. There is a problem that a valuable component accommodating space is occupied by the heat pipe, which causes an increase in the size of the electric connection box 1. Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a heat-dissipating structure of an electric junction box which has an excellent heat-dissipating effect without increasing the cost and can be downsized. Means for Solving the Problems The above object of the present invention is as follows.
An insulating substrate on which a bus bar made of a metal plate is arranged is provided inside a case provided with a component mounting portion on which electronic / electric functional components and the like are mounted, and a connection vertically provided on the bus bar on the insulating substrate. In an electric connection box in which a terminal is electrically connected to a connection terminal of an electronic / electrical functional component facing the inside of the case from the component mounting portion, the terminal covers the bus bar exposed on the surface of the insulating substrate and connects the bus bar. An insulating sheet penetrated by the terminal, and a metal plate formed by outsert molding only the periphery of the insertion hole through which the connection terminal penetrating the insulating sheet is inserted in close contact with an insulating resin having excellent thermal conductivity. Is achieved by the heat dissipating structure of the electric junction box, which is characterized by being stacked and arranged. [0007] According to the above configuration, a metal plate having a high thermal conductivity and a large heat capacity is laminated and provided on the insulating substrate as a heat radiating plate. From the peripheral portion of the insertion hole that is in contact with the connection terminal, the metal portion around the insertion hole can be efficiently dispersed over a wide area, and the bus bar and the connection terminal of the bus bar (including the relay terminal) due to the heat transfer from the electronic and electric components ) Can be suppressed. Further, since an insulating resin portion formed around the insertion hole is formed integrally with the metal plate by outsert molding in order to prevent a short circuit between the connection terminal and the metal plate,
Since the adhesion between the insulating resin portion and the metal portion is high and the thermal conductivity from the insulating resin portion to the metal portion is good, the heat radiation effect is high. Furthermore, since it is only necessary to laminate a thin insulating sheet and a metal plate on the surface of the insulating substrate, the structure is extremely simple and the space occupied in the electric junction box is small, resulting in an increase in the size of the electric junction box. Nor. The outsert molding in the present invention is distinguished from "insert molding" in which a metal part is inserted into a metal mold to form a resin product with metal fittings, and a small resin is formed on a larger metal plate. Means the method of injection molding a part. Further, as the connection terminal of the bus bar according to the present invention, a male tab terminal connected to a connection terminal of an electronic / electrical functional component via a relay terminal or a female tab terminal directly connected can be used. Further, a plurality of insulating sheets and metal plates may be interposed between the insulating substrates to be laminated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a heat radiating structure for an electric junction box according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 are an exploded perspective view and an enlarged cross-sectional view of a main part showing a heat dissipation structure of an electric junction box according to a first embodiment of the present invention. The electric connection box 20 according to the first embodiment is
It is mounted on an automobile or the like and performs connection or branching between terminals such as a wire harness and electronic / electrical components. As shown in FIG. 1, a fuse, a relay, and other electronic / electrical components 2 are mounted. Upper case 22 having component mounting part 4
And a lower case 24 assembled to the lower part of the upper case 22 to define a housing space.
An appropriate number of insulating substrates 26 are arranged in a stacked state inside the substrate. As shown in FIG. 2, the component mounting section 4
The connection terminal 2a of the electronic / electric component 2 mounted on the component mounting portion 4 is connected to a terminal insertion hole 2 formed through the upper case 22.
2 a is inserted into the upper case 22. The insulating substrate 26 includes a bus bar 28 serving as an electric circuit for the electronic / electric component 2 mounted on the component mounting section 4.
But are routed on the surface. The bus bar 28 is formed by punching a metal plate.
A male tab terminal 28a, which is a connection terminal for connecting to the connection terminal 2a of the electric component 2, is integrally formed by bending. A connection terminal 2a of the electronic / electric component 2 facing the inside of the upper case 22 from the component mounting portion 4 and an insulating substrate 26
The male tab terminals 28a suspended from the upper bus bar 28 are electrically connected to the connection terminals 2a and the relay terminals 14 provided with terminal fitting portions 14a at both ends for fitting the male tab terminals 28a. Connected to. The heat dissipation structure of the present embodiment covers the bus bar 28 exposed on the surface of the insulating substrate 26 and the male tab terminal 2 of the bus bar 28.
An insulating sheet 30 penetrated by the insulating sheet 8a and a metal plate 34 in which only the peripheral portion 36 of the insertion hole 32 inserted into the male tab terminal 28a penetrating the insulating sheet 30 is outsert molded with an insulating resin are laminated. Has been deployed. The insertion hole 32 is dimensioned such that the male tab terminal 28a comes into close contact with the inner surface of the hole. The insulating sheet 30 is formed by molding a resin material having excellent insulating properties and thermal conductivity (for example, silicon rubber mixed with ceramic) into a sheet shape, and the through hole 31 through which the male tab terminal 28a penetrates is formed. It is formed corresponding to the arrangement of the male tab terminals 28 a of the bus bar 28 on the insulating substrate 26. The metal plate 34 serving as a heat radiating plate is formed of an insulating resin only at a peripheral portion 36 of the insertion hole 32 through which the male tab terminal 28a is inserted, and is formed of a metal such as aluminum except the peripheral portion of the insertion hole 32. In this structure, a resin portion serving as the peripheral portion 36 of the insertion hole 32 is integrally formed on a metal plate by outsert molding. Then, the insulating substrate 26
The peripheral portion 36 of the insertion hole 32 with which the male tab terminal 28a of the bus bar 28 contacts is formed of an insulating resin, and the metal plate 34 other than the peripheral portion 36 is formed of metal. Since the insulating sheet 30 is interposed between the insulating substrate 26 and the insulating substrate 26, the bus bar 28 on the insulating substrate 26 is not short-circuited. The resin material used for the peripheral portion 36 of the insertion hole 32 is preferably excellent in insulation and heat conductivity, like the insulating sheet 30. That is, according to the heat radiating structure of the electric junction box 20 according to the present embodiment, the metal plate 34 having a high heat conductivity and a large heat capacity is laminated and provided on the insulating substrate 26 as a heat radiating plate. The heat transmitted from the connection terminal 2a to the male tab terminal 28a of the bus bar 28 via the relay terminal 14 due to the heat generated by the component 2 contacts the relay terminal 14 and the male tab terminal 28a as shown by an arrow (a) in FIG. From the peripheral portion 36 of the insertion hole 32, the metal portion around the insertion hole 32 can be efficiently dispersed over a wide range, and the temperature rise of the bus bar 28 and the relay terminal 14 due to the heat transfer from the electronic / electric component 2 is suppressed. be able to. In order to prevent a short circuit between the relay terminal 14 and the male tab terminal 28a and the metal plate 34, an insulating resin portion formed in the peripheral portion 36 of the insertion hole 32 is integrated with the metal plate 34 by outsert molding. Since it is molded, the adhesion between the insulating resin portion and the metal portion is high, and the heat conductivity from the peripheral portion 36 to the metal plate 34 can be improved, so that the heat radiation effect can be enhanced. That is, the peripheral portion 36 of the metal plate 34 formed of an insulating resin may be formed as a resin part separate from the metal part instead of the outsert molding, and may be assembled later. However, a gap occurs during the assembly. As a result, it is difficult to ensure sufficient adhesion, and the performance of dispersing heat from the peripheral portion 36 to the surrounding metal portion is likely to decrease. Furthermore, since it is only necessary to laminate the thin insulating sheet 30 and the metal plate 34 on the surface of the insulating substrate 26, the structure is extremely simple and the electric power is very simple as compared with a conventional heat radiating mechanism using a heat pipe. The space occupied in the connection box 20 can be reduced, and the electric connection box 20 does not become large. Further, by configuring the insulating sheet according to the present invention with a resin material having excellent insulating properties and thermal conductivity like the insulating sheet 30 of the above-described embodiment, the temperature rise due to energization of the bus bar 28 itself is also performed via the insulating sheet 30. The insulating sheet 3
This can be suppressed by the heat transfer effect to the metal portion of the metal plate 34 that is stacked in close contact with the metal plate 34. Incidentally, the electric connection box 2 according to the first embodiment described above.
In the heat dissipating structure of No. 0, the insulating sheet 30 for preventing a short circuit is disposed only between the metal plate 34 and the insulating substrate 26. However, when the insulating sheet has good thermal conductivity, Like the electrical junction box 21 according to the second embodiment shown in FIG. 3, the peripheral terminal 36 of the metal plate 34, which is an insulating resin part, and the metal parts around the peripheral part 36, and the relay terminal The insulating sheet 33 may be partially provided on the surface side of the metal plate 34 so that the end of the metal sheet 14 is seated. In this case, as shown by the arrow (b) in FIG. 3, heat transfer occurs between the relay terminal 14 and the metal portion of the metal plate 34 via the insulating sheet 33, and is transmitted from the electronic / electric component 2 side. The heat dissipated is more efficiently dispersed, and the temperature rise of the bus bar 28 and the relay terminal 14 can be further suppressed. The heat dissipation structure of the electric junction box according to the present invention is not limited to the structure of each of the above embodiments.
It goes without saying that various forms can be adopted based on the spirit of the present invention. For example, in each of the above embodiments, the insulating sheet 30 is made of a material having excellent thermal conductivity so that heat can easily escape from the bus bar 28 on the surface of the insulating substrate 26 to the metal plate 34 via the insulating sheet 30. It was decided to. However, when the heat diffusing property from the peripheral portion 36 of the metal plate 34 to the surrounding metal portion is excellent, and excessive heat rising of the insulating substrate 26 can be prevented without heat conduction in the insulating sheet, It is not necessary to use a material having excellent thermal conductivity for the insulating sheet, and the material may be determined simply from the viewpoint of insulation performance, mechanical strength, and the like. In each of the above embodiments, a male tab terminal 28a is used as a connection terminal of
Although connected to the connection terminal 2a of the electric functional component 2 via the relay terminal 14, by using a female tab terminal as the connection terminal of the bus bar 28, it is directly connected to the connection terminal 2a of the electronic / electric functional component 2. It is good also as composition. Further, a plurality of insulating sheets 30 and metal plates 34 may be interposed between the insulating substrates 26 to be laminated. According to the heat radiating structure of the electric junction box of the present invention, a metal plate having a high thermal conductivity and a large heat capacity is laminated on the insulating substrate as a heat radiating plate. The heat transmitted to the connection terminal of the bus bar due to heat generation can be efficiently dispersed from the periphery of the insertion hole in contact with the connection terminal to a wide range of metal parts around the insertion hole, and the heat transfer from the electronic and electric parts can be performed. The temperature rise of the bus bar and the connection terminal (including the relay terminal) of the bus bar due to the above can be suppressed. Also, since an insulating resin portion formed around the insertion hole to prevent a short circuit between the connection terminal and the metal plate is integrally formed on the metal plate by outsert molding,
Since the adhesion between the insulating resin portion and the metal portion is high and the thermal conductivity from the insulating resin portion to the metal portion is good, the heat radiation effect is high. Furthermore, since it is only necessary to laminate a thin insulating sheet and a metal plate on the surface of the insulating substrate, the structure is extremely simple and the space occupied in the electric junction box is small, resulting in an increase in the size of the electric junction box. Nor. Therefore, it is possible to provide a heat radiating structure of the electric junction box which is excellent in the heat radiating effect without increasing the cost and can be downsized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially exploded perspective view showing a heat dissipation structure of an electric connection box according to a first embodiment of the present invention. FIG. 2 is an enlarged sectional view of a main part of the heat radiation structure shown in FIG. 1 in an assembled state. FIG. 3 is an enlarged cross-sectional view of a main part in an assembled state of a heat dissipation structure according to a second embodiment of the present invention. FIG. 4 is a schematic exploded perspective view showing the structure of a conventional electric junction box. [Description of Signs] 2 Electronic / Electrical Components 2a Connection Terminal 14 Relay Terminal 20 Electric Connection Box 22 Upper Case 26 Insulating Board 28 Bus Bar 28a Male Tab Terminal 30 Insulation Sheet 31 Through Hole 32 Insertion Hole 34 Metal Plate

Claims (1)

(57) [Claim 1] An insulating substrate on which a busbar made of a metal plate is arranged is provided inside a case provided with a component mounting portion on which electronic and electrical functional components and the like are mounted. And an electrical connection box in which connection terminals suspended from a bus bar on the insulating substrate are electrically connected to connection terminals of electronic / electrical functional components facing the inside of the case from the component mounting portion. An insulating sheet that covers the bus bar and that is penetrated by the connection terminal of the bus bar and the connection terminal that penetrates the insulation sheet are in close contact with each other.
Excellent thermal conductivity only around the insertion hole that is inserted by touch
A heat dissipating structure for an electric junction box, wherein a metal plate formed by outsert molding with an insulating resin is laminated.