JP2007129784A - Electric connection box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric connection box in which a substrate cover exhibits good corrosion resistance, prevention of inundation can be carried out simply, and good heat dissipation characteristics can be attained. <P>SOLUTION: The electric connection box comprises a resin box base 2 having an opening 2y, a resin substrate case 3 arranged fixedly in the resin box base 2 while being exposed partially from the opening 2y, a metal core substrate 4 contained in the substrate case 2, and a thermally conductive sheet 5 interposed between the metal core substrate 4 and the bottom face 3a of the substrate case 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric junction box used in a vehicle such as an automobile.

Electrical junction boxes have been used in vehicles such as automobiles.
This electrical junction box is used to simplify the configuration of the wire harness in the vehicle by connecting a wire harness composed of a power line and a signal line.
In recent years, many electrical junction boxes having circuit boards have been used.
In this type of electrical junction box, heat radiation from the electrical junction box is an important issue, and various proposals have been made.
For example, Patent Document 1 proposes a structure in which a substrate cover that protects a circuit board is made of metal and the metal surface is partially exposed from a box base portion that houses the board cover.

JP 2005-269847 A

However, the technique of Patent Document 1 requires a structure that improves the corrosion resistance of the exposed metal surface.
In addition, since the metal surface of the board cover and the resin surface of the box base form a single surface, there is a difference in the coefficient of linear expansion between these metals and the resin. When the temperature rises, there is a possibility that the members may be pressed against each other, and as a countermeasure, an elastic seal member is used. Therefore, there is a concern that it is necessary to use in combination with the labyrinth structure.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electrical junction box that has good corrosion resistance of a substrate cover, can easily perform water immersion prevention treatment on the exposed surface of the substrate cover, and can obtain good heat dissipation characteristics. .

  The electrical junction box according to the first aspect of the present invention is a resin-made box base having an opening, and is arranged and fixed in the box base in a state where a part is exposed from the opening. A resin substrate case; a metal core substrate portion housed in the substrate case; and a heat conductive sheet interposed between the metal core substrate portion and the inner surface of the bottom surface portion of the substrate case. It is characterized by.

  An electrical junction box according to a second aspect of the present invention is the electrical junction box according to the first aspect, wherein a box mounting component is further arranged and fixed in the box base, and the box mounting component is connected to the box. The substrate case is disposed on a relatively narrow side surface of the base, and the substrate case is disposed on a relatively wide side of the box base.

  An electrical junction box according to a third aspect of the present invention is the electrical junction box according to the first or second aspect, wherein the gap between the opening of the box base and the substrate case is either a labyrinth structure or a seal member. One of the features is that it is treated to prevent inundation.

  According to the present invention, it is possible to provide an electrical junction box in which the substrate cover has good corrosion resistance, the exposed surface of the substrate cover can be easily subjected to water infiltration prevention, and good heat dissipation characteristics can be obtained.

Hereinafter, the electrical junction box 1 of the embodiment of the present invention will be described.
1-7 is a figure which shows the electrical-connection box 1 of this embodiment. FIG. 8 is a diagram showing a circuit board 20 of the metal core board portion 4 used in the electrical junction box 1.
As shown in FIGS. 1 to 7, the electrical junction box 1 includes a box base 2 (lower case), a substrate case 3, a relay box 8, connectors 9 a and 9 b, an upper cover 6, and a lower cover 10. ing.

The box base 2 is made of, for example, an inexpensive resin such as polypropylene, and includes a top surface 2a, side surfaces 2b, 2c, 2d, 2e, and a bottom surface 2f.
However, the upper surface portion 2a is opened on the entire surface, forming the first opening portion 2x. The side surface 2b is provided with a second opening 2y surrounded by a peripheral wall surface, and the side surface 2b in which the second opening 2y is formed has a larger area than the opposing side surface 2c. The upper surface portion 2a is inclined with respect to the bottom surface portion 2f.
The substrate case 3 is made of, for example, a nylon heat resistant resin in consideration of heat resistance, and houses the metal core substrate portion 4 therein. The substrate case 3 is accommodated in the box base 2, and as shown in FIG. 4, the outer surface of the bottom surface 3a is exposed from the second opening 2y of the side surface 2b.
As shown in FIG. 7, the connection surface between the second opening 2 y of the box base 2 and the bottom surface portion 3 a of the substrate case 3 is formed between the peripheral wall portion 2 g of the side surface portion 2 b of the box base portion 2 and the bottom surface portion 3 a of the substrate case 3. A so-called labyrinth structure (an intricately shaped structure) is provided on the peripheral edge portion 3b, and a water infiltration prevention treatment is performed by combining the peripheral edge portions 3b.

As shown in FIG. 8, the metal core substrate 4 includes a relay 11, a fuse connector 12, a wire harness connector (hereinafter referred to as a WH connector) 13, etc. on a circuit substrate 20 having a metal core 21. The mounting component 7 is mounted on the surface.
For example, as shown in FIG. 8, the circuit board 20 is obtained by sandwiching a plate-like core material 21 made of a metal having good thermal conductivity such as copper between two insulating coatings 22 and 22. A through hole 23 penetrating the front surface and the back surface is formed, a copper foil portion 24 is formed on the front surface, and a circuit pattern 25 is appropriately formed on the insulating coatings 22, 22. Further, a terminal 26 such as the relay 11, the fuse connector 12, and the WH connector 13 is inserted into the through hole 23 and fixed with solder 27.
The metal core substrate portion 4 is housed in the substrate case 3 as described above, and is disposed and fixed on the inner surface of the bottom surface portion 3 a of the substrate case 3 via the heat conductive sheet 5.
The heat conductive sheet 5 is interposed between the metal core substrate portion 4 and the inner surface of the bottom surface portion 3 a of the substrate case 3.
More specifically, a large number of mounting components 7 are arranged on the front surface of the metal core substrate portion 4, but no mounting components 7 are arranged on the back surface (the circuit itself is formed), and this entire surface is arranged. The heat conductive sheet 5 is stuck and fixed. Furthermore, the opposite side of the heat conductive sheet 5 is stuck and fixed to the inner surface of the bottom surface portion 3 a of the substrate case 3.
Note that a fuse (not shown) is appropriately connected to the fuse connector 12 of the metal core substrate portion 4, and a WH connector (not shown) formed at the end of the wire harness in the vehicle is connected to the WH connector 13.

As described above, the board case 3 is arranged on the side surface 2b side of the box base 2, but on the side surface 2c side, the relay box 8 and the WH connectors 9a and 9b, which are examples of the box mounting components of the present invention, are arranged. Are arranged adjacent to each other.
The relay box 8 is a cassette type, and is housed and assembled in the box base 2 as required, and a WH connector (see FIG. (Not shown).
The WH connectors 9a and 9b are female connectors that connect directly from the wire harness to the wire harness, and are connected to a male connector (not shown) of the wire harness in the vehicle.
The upper cover 6 is engaged with the first opening 2x of the box base 2 by a lock mechanism (not shown).
The lower cover 10 is engaged with the bottom surface 2f of the box base 2 by a lock mechanism (not shown).
The lower cover 10 is formed with a notch 10a through which a wire harness (not shown) connected to the WH connectors 13 and 14 passes.

In the electrical junction box 1 having such a configuration, the electrical junction box 1 can be stored in a given space in the vehicle because the space of the upper surface portion 2a is inclined.
Moreover, in the electrical junction box 1 of this embodiment, since the metal core board | substrate part 4 is used as a circuit board, the heat which generate | occur | produced locally on the metal core board | substrate part 4 is soaked to the whole metal core board | substrate part 4, and a metal core board | substrate. Heat is radiated from the entire surface of the portion 4.
Further, the heat conductive sheet 5 radiates heat from the back surface of the circuit board 20 to the board case 3 side, and the bottom surface part 3a of the board case 3 is exposed from the second opening 2y of the box base part 2, so that the vehicle Heat is dissipated inside.
Here, the substrate case 3 is made of resin as described above, but the circuit board 20 of the metal core substrate part 4 is soaked in temperature, and the electric connection box 1 is efficiently passed from the circuit board 20 via the heat conductive sheet 5. Since heat is radiated to the outside, the heat dissipation characteristics are sufficiently good.
In addition, by utilizing the fact that the box mounting components (relay box 8 and WH connectors 9a and 9b) are smaller than the board case 3, these box mounting components are one-stage when viewed from the upper surface 2a side of the box base 2. It is arranged below, that is, at a low position, and the upper surface portion 2a side is inclined in the box base portion 2 as a whole so as to accommodate the components. That is, the box mounting component is disposed on the relatively narrow side surface portion 2 c side of the box base portion 2, and the board case 3 is disposed on the relatively wide side surface portion 2 b side of the box base portion 2. Therefore, it can be said that the electrical connection box 1 is laid out so that components can be accommodated by making good use of the inclined upper space as described above, and the metal core substrate portion 4 can be configured with a large area.
This further enhances the heat dissipation from the surface of the circuit board 20 of the metal core substrate portion 4 and the bottom surface portion 3 a of the substrate case 3 exposed from the electrical connection box 1.
Further, since the metal core substrate portion 4 is arranged on the side surface portion 2b side that is formed wider than the side surface portion 2c as described above, the layout of the circuit pattern 25 is facilitated, and a large current is applied to the metal core substrate portion 4. It will be able to flow.

Moreover, in the electrical junction box 1 of this embodiment, since the bottom face part 3a of the resin substrate case 3 is exposed from the resin box base 2, the electrical junction box has better corrosion resistance than the metal material. For the portion where the substrate case 3 is exposed from 1, the difference in linear expansion coefficient between the resins is not so large even if different materials are used. Pressure is prevented. Therefore, it is sufficient to adopt a general labyrinth structure between the two members for preventing the infiltration (no need to intervene another seal member between the box base 2 and the substrate case 3).
In order to exert such an effect, it is preferable to use a resin material having a linear expansion coefficient as close as possible to the resin material of the box base 2 and the substrate case 3, and when the same resin material is used, between the two members The difference in linear expansion coefficient is zero, and the above effect is exhibited to the maximum.
In the above-described embodiment, an example in which a labyrinth structure is used as the inundation preventing structure is shown. However, it is of course possible to use a seal member similar to that of Patent Document 1 instead of the labyrinth structure. By using any one of these flood prevention structure, the flood prevention process can be easily performed on the electrical junction box 1. Of course, in the present invention, in order to further improve the water leakage prevention property, both of the water leakage prevention structures may be used in combination, or the use of other water leakage prevention structures is not prevented.
In any case, the use of resin for the box base 2 and the substrate case 3 can improve the water leakage prevention performance as compared with the conventional water immersion prevention structure.

  As described above, according to the present invention, it is possible to provide an electrical junction box in which the substrate cover has good corrosion resistance, can be easily subjected to flooding prevention treatment, and can obtain good heat dissipation characteristics.

It is a disassembled perspective view of the electrical junction box of this embodiment. It is a perspective view which shows the accommodation state of the components in a box base part by removing an upper cover in the electrical junction box of FIG. FIG. 2 is a top plan view illustrating a storage state of components in a box base portion by removing an upper cover in the electrical junction box of FIG. 1. It is the perspective view which looked at the electrical junction box of FIG. 1 from the side part 2b side. FIG. 2 is a side view showing a state in which components in the box base are stored from the side surface portion 2c side by removing the upper cover in the electrical junction box of FIG. 1. FIG. 3 is a side view showing a state in which components in the box base are stored from the side surface portion 2d side with the upper cover removed in the electrical junction box of FIG. 1. It is side surface sectional drawing which shows the state which cut | disconnected the upper cover and box base inside the electrical junction box of FIG. 1 by the AA line of FIG. It is side surface sectional drawing which shows an example of the circuit board of the metal core board | substrate part used with the electrical junction box of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrical junction box 2 Box base 2a Upper surface part 2b, 2c, 2d, 2e Side surface part 2f Bottom surface part 2g Peripheral wall part 2x 1st opening part 2y 2nd opening part 3 Board | substrate case 4 Metal core board | substrate part 5 Thermal conductive sheet 6 Upper Cover 7 Mounting parts 8 Relay box 9a, 9b Connector 10 Lower cover 10a Notch 11 Relay 12 Fuse connector 13, 14 Connector

Claims (3)

A resin-made box base with an opening;
A resin-made substrate case that is disposed and fixed in the box base part in a state where a part is exposed from the opening;
A metal core substrate housed in the substrate case;
A heat conductive sheet interposed between the metal core substrate and the inner surface of the bottom surface of the substrate case;
An electrical junction box characterized by comprising: A box mounting component is further arranged and fixed in the box base,
The box mounting component is disposed on a relatively narrow side surface of the box base,
The electrical connection box according to claim 1, wherein the board case is disposed on a relatively wide side surface of the box base. The electrical junction box according to claim 1, wherein a water-proofing process is performed between the opening of the box base and the substrate case by either a labyrinth structure or a seal member.

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