JP2006271132A - Fixed structure of electric connection box for car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fix an electric connection box which holds a PD and is mounted for a car, in such a state as heat dissipation is made higher. <P>SOLUTION: The power distributor (PD) 20, having a heat sink 26 of a metal radiating plate integrally attached, is housed in a casing 11. The heat sink 26 is positioned at an opening of the casing 11 and is exposed, at least one end side of the heat sink 26 is extended outwardly from the casing 11, and then a car body fixing portion 28 with a bolthole 29 perforated is provided at its extended end portion. A lower cover 13 is fitted to the casing 11, a car body fixing hole 14 is provided at a side of the lower cover 13, and the car body fixing portion 28 of the heat sink 26 is overlapped on a peripheral edge of the car body fixing hole 14, and is fastened and fixed to a car body B with a bolt 30. The lower cover 13 is also fixed to the car body B, at the same time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle body fixing structure for an electric junction box for an automobile that houses a power distributor (PD).

  In recent years, electrical junction boxes for automobiles may be equipped with a power distributor (PD) in which electronic components such as a board relay are mounted on a printed circuit board and a bus bar is fixed on the back side. Since the amount of heat generated is large, the temperature of the inside of the electrical junction box is increased, and a heat sink is essential.

  For example, in Japanese Patent Application Laid-Open No. 2002-315148 (Patent Document 1), as shown in FIG. 3, a conductor plate 2 constituting a power distribution circuit is arranged on substantially the same plane inside the case 1. A semiconductor switching element 3 is mounted thereon, and a heat dissipating member (heat sink) 4 having a plurality of fins 4a arranged in parallel is fixed to the outer surface of the case 1, and the heat dissipating member 4 and the conductor plate 2 are thermally connected. In this way, the heat can be radiated out of the case 1.

  The power distributor having the above-described configuration can release the heat in the case 1 to the outside. However, when the power distributor is housed in the junction box alone or together with the branch connection circuit, etc. The heat released from the case 1 containing the power distributor may cause the inside of the electric junction box to be heated to cause trouble in other electronic components.

In some cases, the heat dissipation plate is connected to a vehicle body made of a metal panel protruding outward from the case, and the vehicle body is used as a heat dissipation material, thereby suppressing temperature rise in the electrical junction box.
However, when the heat radiating plate protrudes from the case, there is a possibility that water may be generated inside the case from the gap between the heat radiating plate and the case. In particular, when an electric junction box is mounted in an engine room in a flooded area, it is necessary to take a waterproof measure.

JP 2002-315148 A

  The present invention has been made in view of the above problems, and relates to an electric junction box for an automobile that houses a power distributor, and to provide a vehicle body fixing structure for an electric junction box with a built-in PD that can achieve both heat dissipation and waterproofing. Is an issue.

In order to solve the above-described problems, the present invention provides an electronic component mounted on a printed conductor surface side of a printed circuit board and a bus bar fixed to the other surface side, and a metal heat dissipation via an insulating layer on the bus bar fixed surface. A power distributor (PD) in which a heat sink made of a plate is integrally assembled is housed inside the case,
The heat sink is exposed by being positioned at an opening provided in the case, and at least one end of the heat sink extends outward from the case, and a bolt hole is formed in the extended tip. While the fixed part is provided,
A lower cover is attached to the case, a vehicle body fixing hole is provided on the lower cover side, a vehicle body fixing portion of the heat sink is overlapped on a periphery of the vehicle body fixing hole, and is bolted to the vehicle body, and the lower cover is also fixed to the vehicle body at the same time. A vehicle body fixing structure for an electric junction box for automobiles is provided.

With this configuration, the heat sink can be fixed to the vehicle body to promote heat dissipation, and the electric junction box itself can be fixed to the vehicle body at the same time. And cost reduction.
In addition, since the heat sink is fixed to the vehicle body in the cover, it is not necessary to protrude the heat sink from the cover, so that waterproof specifications such as a seal necessary for protruding the heat sink from the cover can be eliminated.

A hole is provided on the lower cover side on which the vehicle body fixing portion of the heat sink is overlapped, and a heat conductive member having good heat conductivity and having low hardness and easy adhesion is fitted in the hole. It is preferable. The heat conductive member is preferably formed from a heat conductive metal such as an alumite anodized material, a conductive rubber or the like.
Thereby, the heat from the heat sink can be efficiently conducted to the vehicle body via the heat conductive member, and the heat generated from the power distributor can be radiated more efficiently. The heat conductive member may be insert molded at the time of molding the lower cover.

  An upper cover is provided to cover the case, the front ends of the peripheral walls of the upper cover and the lower cover are connected to each other, and a vehicle body fixing portion of the heat sink that is bolted to the vehicle body is disposed in a hollow portion surrounded by the upper cover and the lower cover Is done.

Thereby, the heat sink is superimposed on the inner peripheral edge of the vehicle body fixing hole of the lower cover, and does not protrude outside the cover, and the case accommodating the power distributor can also prevent direct application of water from the outside. It is possible to prevent water from entering the case through the heat sink from the gap of the projecting portion of the heat sink from the case.
In addition, it is preferable that the washer is made of a low-hardness material, and thereby, it is possible to increase the degree of close contact between the heat sink, the lower cover, and the vehicle body integrally tightened with bolts. The sealing performance against water immersion can be improved.

  As described above, according to the present invention, the heat generated in the power distributor is conducted to both the lower cover and the vehicle body through the heat sink, so that heat can be efficiently radiated. In addition, since the heat sink and the lower cover can be fixed to the vehicle body at the same time by a single tightening operation with one bolt, the workability is improved and the structure is simple and low cost.

  Furthermore, because the thermal conductivity is improved by configuring the periphery of the vehicle body fixing hole of the lower cover with a material having good thermal conductivity, the heat generated by the power distributor is transferred to the lower cover via the heat sink and further to the vehicle body fixing portion. Can efficiently dissipate heat.

  Furthermore, the case and the heat sink containing the power distributor are covered with the lower cover and the upper cover, and the vehicle body fixing part of the heat sink is overlapped on the inner side of the lower cover, so that the case from the gap between the heat sink and the case at the protruding portion of the heat sink. Water can be prevented from entering inside, and in addition to the heat dissipation property, waterproofness can be used.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a vehicle body fixing structure for an automobile electrical junction box according to a first embodiment of the present invention.

  In the present embodiment, the electrical junction box 10 for an automobile includes a case 11 that houses a power distributor 20 alone, an upper cover 12 that covers the upper surface side of the case 11, and a lower cover 13 that covers the lower surface side of the case 11. ing. The peripheral wall 12a of the upper cover 12 is provided with a rib 12b on the inner side along the entire peripheral wall 12a to form a double wall structure, and a packing material P is inserted between the peripheral wall 12a and the rib 12b to form the peripheral wall 13a of the lower cover 13. The upper cover 12 and the lower cover 13 are joined together by fitting the upper end portion.

  As shown in FIG. 1, the power distributor 20 has a plurality of printed conductors 22 forming a power distribution circuit on the upper surface side of a printed circuit board 21, and electronic components such as a printed circuit board relay 23 are mounted on the printed conductor 22. In addition, a plurality of bus bars 24 are fixed to the lower surface side of the printed circuit board 21, and a heat sink 26 made of a metal heat sink is integrally assembled to the lower surface side of the bus bar 24 through an insulating layer 25. Become.

  The power distributor 20 is covered and accommodated by the case 11 from the upper surface side, and the bottom of the case 11 is open, the heat sink 26 is exposed from the bottom opening, and the heat sink 26 One end side is extended to the outside of the case 11. More specifically, the heat sink 26 protrudes from the lower end of the peripheral wall 11a of the case 11 toward the peripheral wall 13a of the lower cover 13, and the front end is bent downward to form a vertical portion 27. The lower end of the vertical portion 27 is the lower cover. The vehicle body fixing portion 28 is formed by being bent in the horizontal direction along the bottom wall 13b of 13. Bolt holes 29 are formed in the vehicle body fixing portion 28.

  A hole 18 for fitting the heat conductive member 15 is provided in the bottom wall 13b of the lower cover 13, and the heat conductive member 15 provided with the vehicle body fixing hole 14 is fitted into the hole 18. The heat conductive member 15 is made of a low-hardness heat conductive metal material such as aluminum alumite material or conductive rubber, and is exposed on both the inner and outer surfaces of the bottom wall 13 b of the lower cover 13.

When the electrical junction box 10 having the above-described configuration is fixed to the vehicle body B, first, the heat conductive member 15 is fitted into the hole 18 of the lower cover 13 and the bolt hole of the vehicle body fixing portion 28 of the heat sink 26 is inserted into the center hole of the vehicle body fixing hole 14. The heat sink 26 and the lower cover 13 are integrally fastened and fixed to the vehicle body B with bolts 30 in a state where the vehicle body fixing portion 28 of the heat sink 26 is in surface contact with the heat conductive member 15.
Thereafter, the upper cover 12 is put on the lower cover 13 and joined. At this time, the packing material P is inserted between the peripheral wall 12a of the upper cover 12 and the rib 12b, and the upper end portion of the peripheral wall 13a of the lower cover 13 is fitted between the peripheral wall 12a of the upper cover 12 and the rib 12b. And tightly coupled through the packing material P.

  With the vehicle body fixing structure, heat generated in the power distributor 20 can be radiated from the heat sink 26 to the lower cover 13 and further to the vehicle body B. In particular, since the heat conductive member 15 made of a heat conductive metal is interposed between the heat sink 26 and the lower cover 13 and the contact portion between the lower cover 13 and the vehicle body B, the heat conductivity is improved and heat can be efficiently radiated.

  Further, since the heat sink 26 assembled to the power distributor 20 is disposed in a hollow portion surrounded by the lower cover 13 and the upper cover 12, external water is not directly applied to the case 11. Further, even if water enters from the hole 18 of the lower cover 13, the case main body 11 and the power distributor 20 are spaced apart from the bottom wall 13 b of the lower cover 13 by the vertical portion 27 of the heat sink 26. It is possible to prevent water from entering the case 11 along the heat sink 26 from the boundary between the heat sink 11 and the heat sink 26. In particular, by tightening and fixing with bolts 30, the gaps between the vehicle body B, the lower cover 13 and the heat sink 26 can be eliminated, and the heat conductive member 15 is formed of a material having low hardness. By utilizing the deformability of the member 15, the vehicle body B, the lower cover 13, and the heat sink 26 can be brought into close contact with each other, and the sealing performance is also improved.

  Furthermore, since the vehicle body fixing structure of the present invention is a simple structure, heat dissipation and waterproofing can be secured at low cost, and the heat sink 26 and the electrical junction box can be simultaneously fixed to the vehicle body B by a single bolting operation. As a result, workability is improved.

FIG. 2 shows a second embodiment of the present invention.
The case 11 is composed of an upper case 11A and a lower case 11B. The case 11 houses a laminated body 41 in which bus bars 42 and insulating plates 43 are alternately laminated in addition to the power distributor 20. Other configurations are the same as those of the first embodiment.

  Specifically, the laminated body 41 is fixed to the upper surface of the bottom wall 11b of the lower case 11B in parallel with the power distributor 20, the printed conductor 22 and the bus bar 24 of the power distributor 20, and the bus bar 42 of the laminated body 41. Electrically connected.

  The bottom wall 11b of the lower case 11B has an opening 11c that is substantially the entire fixed portion of the power distributor 20, and the heat sink 26 assembled to the power distributor 20 is exposed from the opening 11c.

  In the upper case 11A and the lower case 11B, the peripheral wall 11d of the upper case 11A and the distal ends of the peripheral wall 11e of the lower case 11B are fitted and connected to each other, but in some cases, the peripheral wall 11d is not fitted to the distal ends. And an opening 11f surrounded by the peripheral wall 11e. The vertical portion 27 and the vehicle body fixing portion 28 extending from the heat sink 26 protrude out of the case 11 from the opening 11f, and the vehicle body fixing portion 28 is overlapped on the inner surface side of the heat conductive member 15 of the lower cover 13. The bolt 30 is integrally fixed to the vehicle body B.

  Also in the present embodiment, the heat sink 26 is exposed to the outside of the case 11 through the opening 11c formed in the lower case 11B, and can conduct heat to the lower cover 13 and the vehicle body B via the heat conductive member 15. Therefore, heat can be radiated efficiently. Moreover, the point which can ensure high waterproofness, and the point with workability | operativity are the same as that of said 1st embodiment.

  In addition, this invention is not limited to the said embodiment. In particular, the vehicle body fixing hole formed in the lower cover may be provided in the side wall, and the vehicle body fixing portion is not limited to one place, and a plurality of vehicle body fixing portions may protrude from the heat sink.

It is explanatory drawing which shows the vehicle body fixing structure of the electrical-connection box for motor vehicles which concerns on 1st embodiment of this invention. It is explanatory drawing which shows the vehicle body fixing structure of the electrical-connection box for motor vehicles based on 2nd Embodiment of this invention. It is a figure of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electrical connection box for motor vehicles 11 Case 11A Upper case 11B Lower case 13 Lower cover 14 Car body fixing hole 15 Thermal conductive member 20 Power distributor 26 Heat sink 28 Car body fixing part

Claims (3)

An electronic component is mounted on the printed conductor surface side of the printed circuit board and a bus bar is fixed to the other surface side, and a heat sink made of a metal heat sink is integrally assembled to the bus bar fixed surface via an insulating layer. Power distributor (PD) is housed inside the case,
The heat sink is exposed by being positioned at an opening provided in the case, and at least one end side of the heat sink extends outward from the case, and a bolt hole is formed in the extended tip portion. While the fixed part is provided,
A lower cover is attached to the case, a vehicle body fixing hole is provided on the lower cover side, a vehicle body fixing portion of the heat sink is overlapped on a periphery of the vehicle body fixing hole, and is bolted to the vehicle body, and the lower cover is also fixed to the vehicle body at the same time. A vehicle body fixing structure for an electric junction box for automobiles.   2. The vehicle body fixing structure for an electric junction box for an automobile according to claim 1, wherein a periphery including a vehicle body fixing hole on the lower cover side on which the vehicle body fixing portion of the heat sink is overlapped is formed of a material having good thermal conductivity.   An upper cover is provided to cover the case, the front ends of the peripheral walls of the upper cover and the lower cover are connected to each other, and a vehicle body fixing portion of the heat sink that is bolted to the vehicle body is disposed in a hollow portion surrounded by the upper cover and the lower cover The vehicle body fixing structure for an electric junction box for automobiles according to claim 1 or 2.

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