JP3420947B2 - Heat dissipation structure of electrical junction box - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation structure for an electric junction box used for electric wiring of automobiles and the like.

[0002]

2. Description of the Related Art A large number of electric parts are used in automobiles having complicated electric elements, and electric circuits for exchanging information, signals or electric power among these electric parts are collectively interconnected. Therefore, electric junction boxes such as junction boxes and relay boxes are commonly used.

As shown in FIG. 5, in such an electric connection box 30, various electrical parts such as a wiring board assembly and fuses 9 and relays 5 formed by laminating insulating boards on which bus bars are arranged are combined. It is housed in a box body 2 made of resin, and an upper cover 3 for waterproofing and dustproofing is detachably mounted on the component mounting side of the box body 2. These fuses 9,
An input / output electric wire 6 for forming a predetermined circuit is connected to the relay 5 and the like, and the electric wire 6 is drawn out through a through hole 4a formed in the under cover 4. Through hole 4
An insulating tape 7 is wound around the take-out portion of the electric wire 6 pulled out from a together with a harness holding piece 8 protruding from the under cover 4, and is fixed to the under cover 4.

By the way, in recent years, with the increase in the number of electrical components mounted on automobiles and the like, the number of electrical functional parts such as fuses 9 and relays 5 has increased, the circuit density in the electrical junction box has increased, and the electrical junction box Space saving is desired, and the temperature rise value in the box tends to increase. On the other hand, the electric connection box is usually waterproof because there is a risk of short circuit or leakage current flowing when water enters and stays inside the box. There is. For example, in the vicinity of the through hole 4a formed in the under cover 4, the wire bundle is also wrapped with the insulating tape 7 for fixing the harness, and is sealed. As a result, the number of heat generating parts such as heat generating parts and terminal connecting parts increases, and particularly the fusible part of the fuse 9 and the coil part of the relay 5 generate heat, causing functional failures and melting damage to the electric functional parts and the box body 2. I was afraid.

Therefore, for example, like a fuse box disclosed in Japanese Utility Model Laid-Open No. 62-12254, a fuse attached to a fuse socket of a case (box body) and a cover (upper cover) attached to the socket. A fuse box is proposed in which an elastic heat transfer member is interposed between the fuse box and the heat generated in the fuse to be conducted to the cover for cooling.

The elastic heat transfer member is formed of a plate member made of a silicon-based heat radiating grease impregnated rubber which has insulating properties and elasticity and has a high thermal conductivity. Further, the cover having the radiation fins protruding from the top surface is made of a heat transfer material. Therefore, the heat generated by the fuse is transmitted to the cover through the elastic heat transfer member and is positively radiated to the atmosphere through the heat radiation fins.

[0007]

However, in the structure of the fuse box disclosed in Japanese Utility Model Laid-Open No. 62-12254, the heat generated in the fuse body can be dissipated to the outside of the case, but the terminal connecting portion. It is not possible to dissipate the heat inside the case to the outside of the case due to the heat generated by the cable or the wire itself.

Further, in the case of an electric connection box in which electric parts of different shapes such as fuses and relays are mounted, the shape of the elastic heat transfer member interposed between the upper cover and each electric part becomes complicated. A dedicated cover or elastic heat transfer member is required for each vehicle type. Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide an inexpensive heat dissipation structure for an electric junction box that can suppress a temperature rise with a simple structure.

[0009]

The above object of the present invention is to prevent the above problems.
A heat dissipation structure of an electric connection box in which an electric component serving as a heat source is housed in a box body having a water structure, and inside the electric wire bundle of electric wires connected to the electric component and drawn out through a through hole, This is achieved by a heat dissipation structure of an electrical junction box, in which a long heat conducting member extending inside and outside the box body is interposed.

According to the above structure, the heat generated in the waterproof box body is absorbed by the inner end of the box body of the heat conducting member,
Since the heat is dissipated at the outer end of the heat conducting member, the temperature rise in the box body can be suppressed. Further, the heat conducting member interposed inside the electric wire bundle can efficiently exhaust the heat generated by the electric wires to the outside. Further, since the heat conducting member is interposed inside the electric wire bundle during assembly of the harness and is wound with the electric wire with an insulating tape or the like, the waterproof property of the takeout portion of the electric wire drawn out from the through hole does not deteriorate.

It is preferable that a heat radiating portion that extends radially and is in contact with the outside air is provided at the outer end of the heat conducting member. Therefore, by allowing the heat radiating portion to come into contact with the outside air, the heat radiation efficiency at the outer end of the heat conducting member can be improved. Also, preferably, the heat conducting member,
By using a soft resin material having a higher thermal conductivity than the covering material of the electric wire, it is possible to further improve heat dissipation.

Further, the above object of the present invention is a heat dissipation structure of an electric connection box in which electric parts which are heat sources are housed in a box body having a waterproof structure, which is connected to the electric parts and is externally connected through a through hole. This is achieved by a heat dissipation structure of an electrical connection box, in which a continuous heat conductive sheet is wound around the inside and outside of the box main body around the wire bundle of the electric wires drawn out.

According to the above construction, the heat generated inside the waterproof box body is absorbed inside the box body of the heat conductive sheet,
Since the heat is dissipated on the outside of the heat conductive sheet, the temperature rise in the box body can be suppressed. Further, the heat conductive sheet wound around the bundle of electric wires can efficiently discharge the heat generated by the electric wires to the outside. Further, since the heat conductive sheet is wound around the bundle of electric wires when the harness is assembled and the electric wires can be wound in the same manner as the insulating tape or the like, the waterproof property of the electric wire take-out portion pulled out from the through hole is deteriorated. Nothing.

It is preferable that the heat conductive sheet is wound as an insulating tape having an adhesive layer formed on one surface thereof, so that an insulating tape for fixing a harness is not required. Also, the degree of adhesion of the heat conductive sheet to the electric wire is increased, and the heat dissipation can be improved. Further, preferably, the heat conductive sheet is made of a soft resin material having a higher heat conductivity than the covering material of the electric wire, whereby the heat dissipation can be further enhanced.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a fragmentary exploded view of an electric junction box having a heat dissipation structure according to a first embodiment of the present invention, FIG. 2 is an overall perspective view of the heat conducting member shown in FIG. 1, and FIG. FIG. 3 is a sectional view taken along the line III-III of FIG. 1.

The electric junction box 1 shown in FIG. 1 is similar to the electric junction box 30 shown in FIG. 5 in that a wiring board assembly formed by laminating insulating boards with bus bars arranged therein, a fuse 9, and a relay 5 are provided.
Various electric parts such as are housed in a box body 2 made of synthetic resin, and an upper cover 3 for waterproof and dustproof is detachably mounted on the part mounting side of the box body 2. An electric wire 6 for input and output for forming a predetermined circuit is connected to the fuse 9, the relay 5 and the like, and the electric wire 6 is drawn out through a through hole 4a formed in the under cover 4. The take-out portion of the electric wire 6 pulled out from the through hole 4 a is provided with a harness holding piece 8 protruding from the under cover 4.
An insulating tape 7 is wrapped around and fixed to the under cover 4.

Further, the electric wire 6 wound around the insulating tape 7
Inside the electric wire bundle, a long heat conducting member 10 extending between the inside of the box body 2 and the outside is interposed. As shown in FIG. 2, the heat-conducting member 10 is a resin part in which a plurality of heat-dissipating portions 13 extending radially are formed at one end of a simple round bar, and it is preferable that the heat-conducting member 10 has a heat resistance higher than that of the covering material of the electric wire 6. It is made of a soft resin material with high conductivity.

As the soft resin material forming the heat conducting member 10, high heat conductive insulating rubber (composite molding of silicon rubber with special ceramics) or the like can be used.

Therefore, at the time of assembling the harness, the box body inner end 11 of the heat conducting member 10 is inserted into the box body 2, and the outer end 12 having the heat radiating portion 13 is outside the box body 2. It is pulled out so as to be interposed in the bundle of electric wires 6, and together with these electric wires 6, an insulating tape 7
Is rolled. The tip of the heat dissipation portion 13 formed on the outer end portion 12 penetrates the insulating tape 7 and can come into contact with the outside air, as shown in FIGS. 1 and 3. At this time, the heat conducting member 10 made of a soft resin material can be appropriately bent along with the electric wire 6 along the drawing shape, so that the heat conducting member 10 can be easily interposed in the electric wire bundle and hinder the tape winding operation. There is also no.

Next, the electric junction box 1 according to the first embodiment.
The operation of the heat dissipation structure will be described below. The heat generated by the heat generated in the fusible part of the fuse 9 and the coil part of the relay 5 housed in the box body 2 is the inner end 11 of the box body 2 of the heat conducting member 10 inserted in the box body 2. Is absorbed by.

The heat absorbed by the inner end 11 of the box body is transmitted to the outer end 12 through the inside of the heat conducting member 10 having an appropriate diameter, and the surrounding electric wire 6 in contact with the outside air.
Heat is exhausted to the outside through the insulating tape 7. Further, since the outer end 12 of the heat conducting member 10 is provided with the heat radiating portion 13 which extends radially and contacts the outside air, the heat transmitted to the outer end 12 is directly transmitted from the heat radiating portion 13. You can also exhaust heat.

That is, the electrical junction box 1 according to the first embodiment.
According to the heat radiation structure, the heat generated in the box body 2 is radiated to the outside through the heat conducting member 10, so that the temperature rise in the box body 2 can be suppressed. Further, the heat conducting member 10 interposed inside the electric wire bundle of the electric wires 6 drawn out from the electric junction box 1 can efficiently exhaust the heat generated by the electric wires 6 to the outside.

Further, since the heat conducting member 10 is interposed inside the electric wire bundle at the time of assembling the harness and is wound with the insulating tape 7 together with the electric wire 6, the takeout portion of the electric wire 6 pulled out from the through hole 4a of the under cover 4 is taken out. The waterproofness of the will not be reduced. In addition, the heat dissipation structure of the electrical junction box 1 according to the first embodiment only needs to wrap the heat conducting member 10 having a simple shape together with the electric wires 6 with the insulating tape 7, and the box main body 2 and the under cover 4 have a specific shape. Since no structure is needed,
It can be used for electric junction boxes of different shapes and can be applied to any type of vehicle.

The structure of the heat conducting member of the present invention is not limited to the structure of the heat conducting member 10 in the first embodiment, and it goes without saying that various structures can be adopted. For example, the heat conducting member may be a simple round bar,
A plurality of heat conducting members may be interposed inside the electric wire bundle. Further, in order to enhance the heat absorbing property and the heat radiating property, it is possible to form the heat conducting member in a shape such that at least a part of the surface area is increased.

FIG. 4 is a fragmentary front view of an electric junction box having a heat dissipation structure according to a second embodiment of the present invention. However, the same components as those of the electrical junction box 1 shown in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted. Figure 4
In the electric junction box 20 shown in FIG. 1, a heat conductive sheet that is continuous inside and outside the box body 2 is provided around the wire bundle of the electric wires 6 that are drawn out from the through holes 4 a formed in the under cover 4. 21 is wound. Therefore, the electric wire 6
The heat-conducting sheet 21 is wound around the take-out portion of the harness holding piece 8 protruding from the under cover 4, and is fixed to the under cover 4.

The heat conductive sheet 21 is a resin sheet formed in a tape shape, and is preferably made of a soft resin material having a high heat conductivity similar to the heat conductive member 10 of the first embodiment. Therefore, when assembling the harness, the box body 2
The heat conductive sheet 21 is wound from the vicinity of the terminal connection portion of the electric wire 6 connected to the fuse and the relay housed inside to the vicinity of the extraction portion of the electric wire bundle drawn out through the through hole 4a. . Then, both ends of the heat conductive sheet 21 that are wound around are fixed by the insulating tape 7. At this time, the heat conductive sheet 21 made of a soft resin material can be easily wrapped around the wire bundle.

Next, the electric junction box 2 according to the second embodiment.
The operation of the heat dissipation structure of No. 0 will be described below. The heat generated by the heat generated in the fusible portion of the fuse 9 and the coil portion of the relay 5 housed in the box body 2 is transferred to the electric wire 6 in the box body 2.
Of the heat conductive sheet 21 wound around the terminal connection part of the
Heat is absorbed inside the box body. The heat absorbed on the box body side of the heat conductive sheet 21 passes through the heat conductive sheet 21 wound around the electric wire 6 and is wound around the external wire bundle take-out portion. The heat is transmitted to the outside of the conductive sheet 21, and is exhausted to the outside from around the outside of the thermally conductive sheet 21 in contact with the outside.

That is, the electrical junction box 2 according to the second embodiment.
According to the heat dissipation structure of 0, the heat generated in the box body 2 is dissipated to the outside through the heat conductive sheet 21.
The temperature rise in the box body 2 can be suppressed. Further, the heat conductive sheet 20 wound around the electric wire bundle of the electric wires 6 drawn out from the electric junction box 20 can efficiently exhaust the heat generated by the electric wires 6 to the outside.

Further, since the heat conductive sheet 21 is wound around the bundle of electric wires at the time of assembling the harness and the electric wire 6 can be wound in the same manner as the insulating tape, the electric wire 6 taken out from the through hole 4a can be taken out. The waterproofness of the part does not deteriorate. In addition, the heat dissipation structure of the electrical junction box 20 according to the second embodiment only needs to wrap the tape-shaped heat conductive sheet 21 around the electric wire 6, and the box body 2 and the under cover 4 have a specific structure. Since it is not necessary, it can be used for electric junction boxes of different shapes and can be applied to any vehicle type.

The structure of the heat conductive sheet of the present invention is not limited to the structure of the heat conductive sheet 21 in the second embodiment, and it goes without saying that various structures can be adopted. For example, if an adhesive layer is formed on one surface of the heat conductive sheet so that it can be wrapped around the electric wire 6 as an insulating tape, the insulating tape 7 for fixing the harness becomes unnecessary. In this case, the degree of adhesion of the heat conductive sheet to the electric wire 6 is increased, and the heat dissipation can be further enhanced.

[0031]

As is apparent from the above description, the heat dissipation structure of the electric junction box according to the present invention is provided inside the box body inside the electric wire bundle of electric wires connected to the electric parts and drawn out from the through hole. It is formed by interposing a long heat conducting member extending to the outside. Therefore, the heat generated in the waterproof box body is absorbed at the box body inner end of the heat conducting member and radiated at the outer side end of the heat conducting member, so that the temperature rise in the box body is suppressed. can do. Further, the heat conducting member interposed inside the electric wire bundle can efficiently exhaust the heat generated by the electric wires to the outside. Further, since the heat conducting member is interposed inside the electric wire bundle during assembly of the harness and is wound with the electric wire with an insulating tape or the like, the waterproof property of the takeout portion of the electric wire drawn out from the through hole does not deteriorate.

Further, in another heat dissipation structure for an electric connection box of the present invention, heat is continuously applied to the inside and outside of the box body around the wire bundle of electric wires connected to the electric parts and drawn out through the through holes. It is formed by winding a conductive sheet. Therefore, waterproof structure
Since the heat generated in the box body is absorbed inside the box body of the heat conductive sheet and radiated outside the heat conductive sheet, the temperature rise in the box body can be suppressed. or,
The heat conductive sheet wound around the bundle of electric wires can efficiently exhaust the heat generated by the electric wires to the outside. Further, since the heat conductive sheet is wound around the bundle of electric wires when the harness is assembled and the electric wires can be wound in the same manner as the insulating tape or the like, the waterproof property of the electric wire take-out portion pulled out from the through hole is deteriorated. Nothing. Therefore, it is possible to provide an inexpensive heat dissipation structure for an electric junction box that can suppress the temperature rise with a simple structure.

[Brief description of drawings]

FIG. 1 is a fragmentary exploded view of an electrical junction box including a heat dissipation structure according to a first embodiment of the present invention.

FIG. 2 is an overall perspective view of the heat conducting member shown in FIG.

3 is a sectional view taken along the line III-III of FIG.

FIG. 4 is a cutaway front view of an essential part of an electrical junction box including a heat dissipation structure according to a second embodiment of the present invention.

FIG. 5 is a fragmentary exploded view of a conventional electrical junction box having a drainage structure.

[Explanation of symbols]

1 electrical junction box 2 box body 3 upper cover 4 Undercover 4a through hole 5 relays 6 electric wires 7 insulating tape 9 fuse 10 Heat conduction member 11 Box body inner end 12 External end 13 Heat dissipation part

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 10-42428 (JP, A) Japanese Patent Laid-Open No. 8-203336 (JP, A) Actually open 61-83278 (JP, U) Actually open 4- 99310 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02G 3/08 H05K 7/20

Claims (6)

(57) [Claims] 1. A heat dissipation structure for an electric connection box in which an electric component serving as a heat source is housed in a waterproof box body, and a wire bundle of electric wires connected to the electric component and drawn out through a through hole. A heat dissipating structure for an electric connection box, wherein a long heat conducting member extending inside and outside the box body is interposed inside the box. 2. The heat dissipating structure for an electrical junction box according to claim 1, wherein a heat dissipating portion that extends radially and is in contact with the outside air is provided at an outer end of the heat conducting member. . 3. The heat dissipation structure for an electrical junction box according to claim 1, wherein the heat conducting member is made of a soft resin material having a higher heat conductivity than the covering material of the electric wire. 4. A heat dissipation structure for an electric connection box in which an electric component serving as a heat source is accommodated in a waterproof main body, and a bundle of electric wires connected to the electric component and drawn out through a through hole. A heat dissipating structure for an electrical connection box, characterized in that a heat conductive sheet is continuously wound around the inside and outside of the box body. 5. The heat dissipation structure for an electrical junction box according to claim 4, wherein the heat conductive sheet is wound as an insulating tape having an adhesive layer formed on one surface thereof. 6. The heat dissipation structure for an electrical junction box according to claim 4, wherein the heat conductive sheet is made of a soft resin material having a higher heat conductivity than the covering material of the electric wire.