JP2006019711A - Electrical junction box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrical junction box which is capable of enhancing the heat dissipation efficiency. <P>SOLUTION: An electrical junction box comprises a heater element 104; a board 105 on which the heater element is mounted; a metal heat collection portion 106A secured to the board; an enclosure 101 which houses the heater element, the board, and the heat collecting portion; a leg portion secured to the heat collecting portion; and metal heat dissipating portion 107C and 108C secured to the leg portion. The metal heat dissipating portion comprises a cylindrical portion 117 which is exposed to the outside of the enclosure and has a cylindrical shape; a heat dissipation window 109 which is formed on one end of the cylindrical portion; and an air-intake window 116 which is formed on the other end of the cylindrical portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrical junction box, and more particularly, to an electrical junction box that can improve heat dissipation efficiency.

  2. Description of the Related Art Conventionally, an electrical connection box including a printed circuit board on which a heating element is mounted and a heat radiating plate is known, and is used in, for example, automobiles. FIG. 6 is a side sectional view showing a configuration of a conventional electrical junction box 10. In the figure, an electrical junction box 10 includes a box-shaped upper cover 11 having an opening on the lower surface side and having a lock portion 11a, and a lower cover 12 fitted to the upper cover 11 and having a lock portion 12a.

  A heat radiating plate 13 for external heat radiation is fixed to a central portion of the bottom portion 12b of the lower cover 12 in the shape of a metal rectangular plate. Insertion holes 13a through which the shaft portions 14a of the respective screws 14 are inserted are formed in the corner portions of the four corners of the heat radiating plate 13, respectively. On both sides of the heat radiating plate 13, heat radiating plates 15, 15 for radiating the heat generating elements are fastened and fixed via the screws 14.

  On both sides of the lower end of the heat radiating plate 15, a pair of leg portions 16, 16 are bent outward by 90 °. A pair of midway portions 17 and 17 are bent inward by 90 ° at the center below the heat sink 15. Each leg portion 16 of the heat radiating plate 15 for radiating the heat generating element extends downward from each midway portion 17. A screw hole 16 a is formed at the center of each leg 16. The shaft portion 14a of the screw 14 inserted through the insertion hole 13a of the heat radiating plate 13 for external heat radiation is screwed into the screw hole 16a, so that the heat radiating plate 15 for heat radiating the heat generating element becomes the heat radiating plate 13 for external heat radiation. It is designed to be fastened and fixed on the top.

  Further, through holes 17a through which the shaft portions 18a of the respective screws 18 are inserted are formed in the respective intermediate portions 17 of the heat radiating plate 15 for radiating the heat generating elements. The shaft portion 18 a of the screw 18 inserted through the insertion hole 17 a is screwed into the screw hole 19 a of the printed circuit board (substrate) 19, whereby a pair of intermediate portions 17, 17 of the heat radiating plate 15 for radiating each heat generating element. The printed circuit board 19 is fastened and fixed.

  A plurality of heating elements 20 are mounted on the printed circuit board 19 so as to be in contact with the heat dissipation plate 15 for radiating each heating element, and various chip components (electronic components) 21 are mounted. Further, on both sides of the printed board 19, U-shaped notches 19b into which the legs 16 of the heat radiating plates 15 for radiating the heat generating elements are inserted are formed.

JP-A-10-262317

  Recently, as more functions are added to automobiles, heating elements for controlling and protecting power supply and information communication circuits are installed on the printed circuit board of the electrical junction box. It is in a situation that must be installed in large numbers. In such a situation, the amount of heat generated on the printed circuit board increases, and a means for efficiently radiating heat from the electrical junction box to the outside is required. That is, conventionally, an electrical junction box with high heat dissipation efficiency has become necessary.

  However, in the conventional electric junction box 10, as shown in FIG. 6, the effective area of the heat radiating plate 13 for external heat radiation is limited by the bottom surface area of the electric junction box 10, and Only one side is exposed to the outside. For this reason, there is a problem that the heat radiation efficiency is low because the heat radiation mechanism is left to simple natural convection and various types of heat transfer on one side of the heat radiation plate 13.

In order to increase the heat dissipation efficiency, measures such as increasing the interval between the heating elements or increasing the heat dissipation surface may be taken. However, the space of the electric junction box 10 in the automobile is limited, so it is no longer necessary. Increasing the size of the electric junction box 10 has become impossible to cope with.
In order to increase the heat dissipation efficiency, it is conceivable to newly provide cooling parts such as fans. However, problems such as an increase in the cost of automobiles and the need for electric power will arise. Even if there is no separate component that consumes power, the heat inside the housing can be released to the outside with low cost and high heat dissipation efficiency so that it can cope to some extent with the increase in the amount of heat generated by the electrical junction box 10 due to the increase in heat generating components A possible electrical junction box 10 was sought.

  The present invention has been made in view of the above problems, and provides an electrical junction box that can discharge heat inside the housing to the outside with low cost and high heat dissipation efficiency and can be downsized. For the purpose.

  In order to solve the above-described problems and achieve the object, the present invention provides a heating element, a substrate on which the heating element is mounted, a metal heat collecting portion fixed to the substrate, the heating element, A housing for housing the substrate and the heat collecting portion; a leg portion fixed to the heat collecting portion; a tubular portion fixed to the leg portion and exposed to the outside of the housing; And a metal heat dissipating part including a heat dissipating window formed on one end side of the cylindrical part and an air intake window formed on the other end side.

According to such a configuration, the heat generated from the heating element is conducted from the substrate to the heat radiating part via the heat collecting part. In the heat dissipating part, the heat is conducted from the leg part to the cylindrical part and released to the surface and the inner surface of the cylindrical part. Here, since the heat collecting part and the heat radiating part are all made of metal, the heat generated by the heating element is quickly transferred to the outside of the housing.
Moreover, since the inside of the cylindrical portion is a closed space where heat is likely to be locally trapped, an upward air flow is generated when the air is heated. Here, the electric junction box of the present invention is used so that the heat radiation window is positioned on the upper side when in use. Therefore, the heated air in the cylindrical portion is released to the outside from the heat radiating window by the upward air flow. At the same time, new heat is taken into the cylindrical portion from the intake window.
In this way, the cylindrical part is not only a simple heat transfer or natural convection to the air on the surface and the inner surface, but also has a structure that promotes convection with the outside air by the chimney effect, so that heat is dissipated. Efficiency can be increased.
Here, since the structure of such a heat collection part and a heat radiation part is comprised with the metal, since workability is good and a shape does not become so complicated, it can be comprised at low cost instead of a function. .
In the present invention, if the heat generating elements are arranged as close as possible, the temperature gradient between the substrate and the heat collecting part can be ensured accordingly, so that heat conduction from the substrate to the heat collecting part is performed quickly. . Therefore, since the substrate can be easily miniaturized, the electrical junction box can be miniaturized.
Therefore, according to the present invention, it is possible to provide an electrical junction box that can release heat inside the housing to the outside with low cost and high heat dissipation efficiency and can be downsized.

  In the above invention, the heat radiating portion may be configured by overlapping a plurality of substantially U-shaped heat radiating plates so that the respective externally exposed portions are located at a predetermined interval.

  In this case, the heat radiating portion can be configured only by combining a very simple substantially U-shaped heat radiating plate.

  In the above invention, the substrate may be a metal core substrate in which a metal core is sandwiched between insulating layers.

  In this case, since the metal core substrate can quickly transfer the heat generated by the heat generating element to the metal core, the heat destruction of the heat generating element is prevented.

  In the above invention, the metal core of the metal core substrate may be connected to the heat collecting part directly or via a buffer layer having higher thermal conductivity than that of the insulating layer.

  In this case, since the heat of the substrate is conducted to the heat collecting part without passing through the insulating layer, the heat radiation efficiency is improved, which is preferable.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical junction box which can discharge | release the heat | fever inside a housing | casing outside with low cost and high heat dissipation efficiency, and can be reduced in size can be provided.

  Below, the Example of the electrical-connection box concerning this invention is described in detail based on drawing. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a perspective view showing a configuration of an electrical junction box 100 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line XX ′ shown in FIGS. 1 and 4. 3 is a cross-sectional view showing a state in which the substrate 105, the heat collecting plate 106A, the heat collecting plate 106B, the heat radiating plate 107, and the heat radiating plate 108 shown in FIG. 2 are disassembled. 4 is a cross-sectional view taken along line YY ′ shown in FIG.

  The electrical connection box 100 is a connector having a fuse module portion having an electric distribution bus bar and fuses, a mounting component module portion having a relay, power MOSFET, electric resistance, etc. mounted on a substrate, and a connector connected to a wire harness. And a module part.

  Specifically, in the electrical junction box 100, the upper case 101 shown in FIGS. 1 and 4 has a substantially box shape with an open bottom surface and accommodates the above-described mounting component module section. The lower case 102 has an upper surface opened and is provided below the upper case 101. The lower case 102 accommodates the connector module portion described above. The lower cover 103 is provided at the lower part of the upper case 101 through a lock portion (not shown) so as to cover the lower case 102. The upper case 101, the lower case 102, and the lower cover 103 constitute a casing.

  The heating element 104 is mounted on the substrate 105 and is a power MOSFET or the like. The substrate 105 is a metal core substrate that is provided in the upper case 101 and has high thermal conductivity. As shown in FIG. 2, the heat collecting plate 106 </ b> A has a substantially L-shaped cross section, and is attached along one side of the substrate 105 with a screw (not shown) through a heat conductive sheet. Yes.

  The heat collecting plate 106B has a substantially L-shaped cross section in the same manner as the heat collecting plate 106A, and extends along the other side of the substrate 105 with a screw (not shown) through a heat conductive sheet (not shown). Attached. That is, the heat collecting plate 106A and the heat collecting plate 106B are disposed to face each other. Further, the heat collecting plate 106A and the heat collecting plate 106B have a function of collecting heat generated by the heating element 104.

FIGS. 5A to 5C are diagrams showing an example of a connection structure between the substrate 105 and the heat collecting plates 106A and 106B.
As shown in FIG. 5A, the substrate 105 is a metal core substrate made of a metal core 105a made of a metal having good thermal conductivity such as copper or aluminum, and insulating layers 105b and 105c sandwiching the front and back surfaces of the metal core 105a. It is. The metal core substrate is excellent in temperature-uniforming action and can dissipate the heat of the heat generating element 104 to each part of the substrate, so that the heat generating element 104 is prevented from being thermally destroyed due to a local high temperature.
Although a circuit pattern is formed on the substrate 105, the illustration is omitted here. At the connection between the substrate 105 and the heat collecting plates 106A and 106B, the heat collecting plates 106A and 106B are fixed on the insulating layer 105b via the buffer layer 114 such as a heat conductive sheet.

  The buffer layer 114 is made of a material having good thermal conductivity and good adhesion to the substrate 105 and the heat collecting plates 106A and 106B, such as an EFCO TM sheet manufactured by EFCO. Therefore, heat conduction from the substrate 105 to the heat collecting plates 106 </ b> A and 106 </ b> B is efficiently performed through the buffer layer 114.

Further, as shown in FIG. 5 (b), the insulating layer 105b is not provided at the connection portion between the substrate 105 and the heat collecting plates 106A and 106B, and the substrate 105 with the exposed metal core 105a is used, and directly on the exposed metal core 105a. The heat collecting plates 106A and 106B can be fixed by screwing or the like.
In this case, heat conduction from the substrate 105 to the heat collecting plates 106A and 106B is performed without using the insulating layer 105b, which often uses a material that does not take heat conductivity into consideration. Compared to the case, the thermal conductivity between the metal core 105a and the heat collecting plates 106A and 106B is improved, which is preferable.

Further, as shown in FIG. 5C, the substrate 105 in which the metal core 105a is exposed without the insulating layer 105b at the connection portion between the substrate 105 and the heat collecting plates 106A and 106B is used. A buffer layer 114 selected from a heat conductive sheet or the like may be formed, and the heat collecting plates 106A and 106B may be fixed thereon by screwing or the like.
In this case, it is preferable because the adhesion between the metal core 105a and the heat collecting plates 106A and 106B is increased and the thermal conductivity is further improved as compared with the case of FIG.

The heat collected by the heat collecting plates 106 </ b> A and 106 </ b> B is transmitted to the heat radiating unit 115 including the heat radiating plate 107 and the heat radiating plate 108.
The heat radiating plate 107 has a substantially U-shaped cross section (see FIG. 3) formed of two side plates (leg portions 107a and 107b) and a back plate (externally exposed portion 107c) fixed between the side plates by bending or the like. And has a function of dissipating heat generated by the heat generating element 104 from the external exposed portion 107c to the outside. The leg portions 107a and 107b of the heat radiating plate 107 are aligned with the respective surfaces of the heat collecting plate 106A and the heat collecting plate 106B, and the heat collecting plate is screwed (not shown) through a heat conductive sheet (not shown). It is attached to 106A and the heat collecting plate 106B. The externally exposed portion 107 c of the heat radiating plate 107 is exposed to the outside from the upper case 101.

The heat sink 108 has a substantially U-shaped cross section (see FIG. 3) that is slightly larger than the heat sink 107 and has a similar shape. That is, the heat radiating plate 108 has a substantially U-shaped cross section (see FIG. 3) formed of two side plates (leg portions 108a and 108b) and a back plate (externally exposed portion 108c) fixed between the side plates. It is formed and has a function of dissipating heat generated by the heating element 104 from the external exposed portion 108c to the outside. The leg portions 108a and 108b of the heat radiating plate 108 are fitted to the respective surfaces of the leg portion 107a and the leg portion 107b of the heat radiating plate 107 by means of screws (not shown) via heat conductive sheets (not shown). It is attached to the part 107a and the leg part 107b.
The externally exposed portion 108c of the heat sink 108 is exposed to the outside from the upper case 101.
As shown in FIG. 2, the heat dissipating part 115 overlaps the plurality of substantially U-shaped heat dissipating plates 107 and 108 so that the externally exposed parts 107c and 108c are positioned with a predetermined interval W therebetween. It is configured to be fixed with screws.

As shown in FIG. 4, the heat radiating plate 107 and the heat radiating plate 108 are provided in a multistage configuration such that a gap 109 is formed between the external exposed portion 107 c and the external exposed portion 108 c. The heat radiating window 110 is formed between the flange 113 provided on the upper part of the upper case 101 and the externally exposed portion 107c, and the heat (air) raised by the chimney effect is externally transmitted through the heat radiating path 111 in the gap 109. It is a window for radiating heat. The intake window 116 is for taking in air of a new low temperature into the gap 109. The housing 112 is provided on the upper part of the upper case 101.
As described above, the heat dissipating part 115 has the cylindrical part 117 outside the upper case 101 and the lower cases 102 and 103, and the cylindrical part 117 has the heat dissipating window 109 at the upper end and the intake window 116 at the lower end. And has both ends opened.

According to the electrical junction box 100 of the present embodiment, the heat generated from the heating element 104 is conducted from the substrate 105 to the heat radiating portion 115 via the heat collecting plates 106A and 10B. In the heat dissipating part 115, the heat is conducted from the leg parts 107 a, 107 b, 108 a, 108 b to the cylindrical part 117 and released to the surface and the inner surface of the cylindrical part 117. Here, since heat collecting plates 106A and 106B and heat radiating portion 115 are all made of metal, heat generated by heating element 104 is quickly transferred to the outside of the housing.
Moreover, since the inside of the cylindrical part 117 becomes a closed space in which heat is likely to be trapped locally, ascending airflow is generated when the air is heated (chimney effect). Here, as shown in FIG. 4, the electrical junction box 100 of the present embodiment is used so that the heat radiation window 110 is positioned on the upper side during use. Therefore, the heated air in the cylindrical portion 117 is released from the heat radiation window 110 to the outside by the upward airflow. At the same time, new heat is taken into the cylindrical portion 117 from the intake window 116. By repeating these operations, air convection is promoted inside and outside the cylindrical portion 117.
As described above, the cylindrical portion 117 has not only simple heat transfer and natural convection to the air on the surface and the inner surface, but also a structure that promotes convection of the air inside the cylindrical portion 117 with external air by the chimney effect. The heat dissipation efficiency can be increased.

Here, the structure of the heat collecting plates 106A and 106B and the heat radiating portion 115 is made of metal, so that the workability is good and the shape is not so complicated as shown in FIG. , 108 are overlapped at a predetermined interval W, so that they can be configured at low cost instead of function.
In the present embodiment, the heat collecting plates 106A and 106B and the heat radiating portion 115 are described as separate components. However, for example, the heat collecting plates 106A and 106B and the heat radiating plate 107 may be integrated.

Further, in the electrical junction box 100 of the present embodiment, as shown in FIG. 3, if the heating element 104 is arranged as close as possible, the temperature of the substrate 105 is increased accordingly, and the substrate 105 and the heat collecting plates 106A and 106B. Therefore, the heat conduction from the substrate 105 to the heat collecting plates 106A and 106B is performed promptly. Accordingly, the substrate 105 can be easily downsized, and the electrical junction box 100 can also be downsized.
Therefore, according to the electrical junction box 100 of the present embodiment, it is possible to provide an electrical junction box that can release heat inside the housing to the outside with low cost and high heat dissipation efficiency, and can be downsized. .

  As described above, the electrical junction box according to the present invention is useful for a case where a heating element that generates a large amount of heat is mounted.

It is a perspective view which shows the structure of the electrical junction box 100 by one Example concerning this invention. FIG. 5 is a sectional view taken along line XX ′ shown in FIGS. 1 and 4. It is sectional drawing which shows the state which decomposed | disassembled the board | substrate 105, the heat collecting plate 106A, the heat collecting plate 106B, the heat sink 107, and the heat sink 108 which were shown in FIG. FIG. 2 is a cross-sectional view taken along line YY ′ shown in FIG. 1. (A)-(c) is sectional drawing which shows the example of a structure about the board | substrate 105, the heat collecting plate 106A, and the heat collecting plate 106B which were respectively shown in FIG. It is a sectional side view which shows the structure of the conventional electrical junction box.

Explanation of symbols

100 Electrical Junction Box 101 Upper Case 104 Heating Element 105 Substrate 106A Heat Collection Plate (Heat Collection Unit)
106B Heat collector (heat collector)
107 Heat sink 108 Heat sink

Claims (4)

  A heating element, a substrate on which the heating element is mounted, a metal heat collecting part fixed to the substrate, a housing for housing the heating element, the substrate, and the heat collecting part, and the heat collecting part A fixed leg portion, a cylindrical portion fixed to the leg portion and exposed to the outside of the casing and having a cylindrical shape, a heat radiating window formed on one end side of the cylindrical portion, and the other end An electrical junction box comprising a metal heat dissipating part and an air intake window formed on the side.   2. The electricity according to claim 1, wherein the heat dissipating part is configured by superposing a plurality of substantially U-shaped heat dissipating plates so that the respective externally exposed parts are located at a predetermined interval. Connection box.   The electrical connection box according to claim 1, wherein the substrate is a metal core substrate in which a metal core is sandwiched between insulating layers.   4. The electrical connection according to claim 3, wherein the metal core of the metal core substrate is connected to the heat collecting part directly or through a buffer layer having higher thermal conductivity than that of the insulating layer. box.

Images