JP2007116808A - Board module and electric connection box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a board module suitable for vehicle mounting, improved in heat radiation and easy in size reduction, and an electric connection box. <P>SOLUTION: The board module comprises: a circuit board 2; a terminal 4 fixed to the circuit board in a state that its tip 4a is protruded from one face 2a of the circuit board 2; and a case 5 for accommodating the circuit board. An insulative heat conduction sheet 6 is tightly fixed to one face of the circuit board, the case is tightly fixed to a face opposite to the circuit board fixing face of the heat conduction sheet, and a recess 5a is formed at the case in such a manner that the recess is away from the tip of the terminal to an appropriate position of the tip. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

   The present invention relates to a board module in which a circuit board is accommodated and an electrical junction box in which the board module is accommodated, which is used in an electrical junction box of an automobile.

Conventionally, in an electrical junction box, a circuit board has been arranged at the center inside the case (see Patent Document 1).
In recent years, there has also been a mode in which a circuit board is temporarily housed in a small case to form a board module, and the board module is further housed in an electrical junction box.
In any case, the circuit board was arranged at the center inside the case.

Japanese Patent Laid-Open No. 10-032914

However, in recent years, heat generating parts such as relays and fuses have been mounted on circuit boards used in, for example, electric junction boxes of automobiles. It was difficult to release heat out of the case.
In addition, there is a high demand for miniaturization of such a board module, but the space around the circuit board is wasted.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a board module and an electrical junction box that are suitable for in-vehicle use, have good heat dissipation and can be easily downsized.

  The board module of the present invention is a board module having a circuit board, a terminal fixed to the circuit board in a state in which a tip protrudes from one surface of the circuit board, and a case for housing the circuit board. An insulating heat conductive sheet is tightly fixed to one surface of the substrate, the case is firmly fixed to the surface of the heat conductive sheet opposite to the circuit substrate fixing surface, and the case has a tip of the terminal. A concave portion is formed at a corresponding position so as to escape from the tip.

  An object of the present invention is to provide a board module and an electrical junction box that are suitable for in-vehicle use, have good heat dissipation and are easy to downsize.

A substrate module 1 according to an embodiment of the present invention is shown in FIG.
As shown in FIG. 1, the board module 1 shows an example applied to an electric junction box of an automobile. The circuit board 2 is connected to the circuit board 2 with solder through a through hole 3, and the tip 4a is connected to the circuit board 2 as shown in FIG. Terminal 4 projecting from one surface 2a, and a case 5 for housing the circuit board 2.

FIG. 2 shows details of the circuit board 2.
The circuit board 2 is a so-called metal core board. For example, as shown in FIG. 2, a plate-like core material 41 made of a metal having good thermal conductivity such as copper is sandwiched between two insulating coatings 42 and 42. The through-hole 3 penetrating the one surface 2a and the other surface 2b is formed, the copper foil portion 44 is formed on the surface, and the circuit pattern 45 is appropriately formed on the insulating coatings 42 and 42. In this structure, they are further covered with an insulating solder resist 48, and the terminals 4 such as connectors 8 are inserted into the through holes 3 and fixed with solder 47.
Such a circuit board 2 has excellent temperature-uniforming characteristics, and can be used very suitably as the circuit board 2 of an electric junction box for automobiles.
It is also possible to increase the functionality by forming an inner layer pattern made of copper foil at the insulating coating 42 and forming a more complicated circuit pattern as a whole.

As shown in FIG. 1, various mounting components 7 such as resistors and capacitors are mounted on one surface 2 a of the circuit board 2. A relay 9 and a connector 8 are mounted on the other surface 2b of the circuit board.
The terminal 4 is fixed to the connector 8 and the circuit board 2, for example, and electrically connects a circuit pattern and a fuse or wire harness (not shown).
The connector 8 is fixed on the other surface 2b of the circuit board 2 and is connected to the connector or fuse of the wire harness.
An insulating heat conductive sheet 6 is tightly fixed to one surface 2 a of the circuit board 2, and a case 5 is firmly fixed to the surface of the heat conductive sheet 6 opposite to the circuit board fixing surface.
The heat conductive sheet is a sheet-like material having an insulating property and a very high heat conductivity, for example, a resin sheet such as an EFCO TM sheet manufactured by FP Corporation.
By making the heat conductive sheet 6 insulative, the terminals 4 are prevented from being short-circuited.
As shown in FIG. 1, since the heat conductive sheet 6 can be easily deformed, it is pushed and deformed by the tip 4 a of the terminal 4. Note that the tip 4 a of the terminal 4 may pierce the heat conductive sheet 6.

According to the board module 1 having such a configuration, electricity can be transmitted via the circuit board 2 via the connector 8 and the wire harnesses can be electrically connected to each other and the circuit can be switched by the relay 9. it can.
Further, according to the board module 1 of the present embodiment, heat generated by, for example, the relay 9 on the circuit board 2 can be conducted to the case 5 via the heat conductive sheet 6 and released to the outside of the case 5.

Assuming that this board module 1 is used in an electrical junction box for automobiles, in the case where the case 5 and the tip 4a of the terminal 4 are in direct contact with each other, the vibration of the case 5 propagates to the terminal 4 and the through hole Problems such as cracks in the solder in 3 are assumed.
Further, in order to avoid this, it is conceivable that the influence of the vibration of the case 5 is made difficult to propagate to the terminals 4 by configuring the heat conductive sheet 6 to be thick. However, the cost of supplying the heat conductive sheet 6 that is often circulated at high cost is further increased.
Therefore, in the present embodiment, the case 5 is formed with a recessed portion 5a at a corresponding position of the tip 4a of the terminal 4 so as to escape from the tip 4a. Therefore, the risk of the influence of the vibration of the case 5 being propagated to the terminal 4 is prevented, and the heat conductive sheet 6 can be formed thin.
In addition, if a large number of the recessed portions 5a are formed in the case 5, the surface area of the case 5 can be increased, so that heat dissipation can be enhanced.
As the material of the case 5, a resin may be used for reducing the component cost, or a metal may be used for improving the heat dissipation. However, in the case of using the resin, it is considered that the resin directly contacts the heat conductive sheet 6. However, it is preferable to use a heat-resistant material.

In the present embodiment, since the mounting component 7 is also mounted on the one surface 2a side of the circuit board 2, the case 5 is also formed with a recessed portion 5a that escapes the mounting component 7a.
As a result, the board module 1 can be further reduced in size, and heat from the mounted component 7 can be directly transmitted to the heat conductive sheet 6 without passing through the circuit board 2.

FIG. 3 shows an electrical junction box 100 according to an embodiment of the present invention.
The electrical connection box 100 is configured such that the board module 1, the relay box 104, the connectors 105, 105, etc. are housed in the lower case 102, and the lower side is covered with the lower cover 103 and the upper side is covered with the upper cover 101.
The portion of the case 5 of the substrate module 1 where the recess 5 a is formed is disposed in a state exposed from the opening 102 a of the lower case 102.
Thus, by storing the board module 1 in the housing with the recessed portion 5a exposed, a very high heat dissipation performance is achieved, and the miniaturization is facilitated.
As described above, according to the present invention, it is possible to provide a board module and an electrical junction box that are suitable for in-vehicle use, have good heat dissipation and can be easily downsized.

It is a partial sectional side view which shows the board | substrate module used as embodiment of this invention. It is a partial sectional side view which shows the part of the circuit board of the board | substrate module of FIG. It is a component block diagram at the time of using the board | substrate module of FIG. 1 within an electrical junction box.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate module 2 Circuit board 3 Through hole 4 Terminal 5 Case 5a Recessed part 6 Thermal conductive sheet 7 Mounted part 8 Connector 9 Relay 41 Core material 42 Insulation coating 44 Copper foil part 45 Circuit pattern 47 Solder 48 Solder resist 100 Electrical connection box 101 Upper cover 102 Lower case 102a Opening 103 Lower cover 104 Relay box 105 Connector

Claims (2)

A board module having a circuit board, a terminal fixed to the circuit board with a tip protruding from one surface of the circuit board, and a case for housing the circuit board,
An insulating heat conductive sheet is tightly fixed to one surface of the circuit board, and the case is firmly fixed to the surface of the heat conductive sheet opposite to the circuit board fixed surface,
The board module according to claim 1, wherein a concave portion is formed at a corresponding position of the tip of the terminal so as to escape from the tip.   An electrical junction box, wherein the board module according to claim 1 is housed in a housing in a state where the recess is exposed.

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