JPH08275335A - Electric connection box - Google Patents

Abstract

PURPOSE: To provide an electronic connection box in an engine room, in which heat is radiated outside surely without impairing water-proof characteristics. CONSTITUTION: An electronic connection box 10 for storing an electric component in a resin-made case has a surrounding double wall made up of an outer wall 12a and an inner wall 12b at a distance from each other. The interior of the inner wall 12a is used as an inner storing chamber, while the inner wall 12a has a ventilation slit 12i. The outer wall 12b has an air intake hole 12c and discharge hole 12d. The air intake hole 12c is connected to an intake duct, and the discharge hole 12d is connected to an discharge duct to discharge heat from the electric component storing chamber outside through ventilation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical connection box for branching and connecting a wire harness for an automobile, and more specifically, an internal circuit member such as a bus bar and electrical parts such as a relay and a fuse are housed inside a case, It is intended to radiate heat from an electric junction box installed in a high temperature atmosphere such as inside.

[0002]

2. Description of the Related Art Conventionally, various electric connection boxes used for branching and connecting a wire harness for an automobile to each electric component have been provided. Among these electric connection boxes, electric connection boxes for accommodating relays and fuses are provided. In the box, it is absolutely necessary to avoid ingress of water into the box. Therefore, the case of this kind of electrical junction box is composed of an upper case and a lower case made of synthetic resin, and a seal packing is attached to the mating surface of the upper case and the lower case to seal in a sealed state and waterproof. I am trying.

Since the relay in the relay box (R / B) mounted inside the sealed case and the fuse in the fusible link box (F / B) are heat-generating parts,
Heat easily accumulates inside the case of the electrical junction box and the temperature rises. Further, when the electric junction box is installed in the engine room, the internal temperature further rises due to the heat of the engine. Especially, in the electric connection box installed in the engine room,
In many cases, an electronic control unit (ECU) such as an electronic fuel injection device (EFI) of the engine is mounted, and if the internal temperature of the electric junction box rises, the ECU may malfunction due to the influence of heat.

On the other hand, Japanese Utility Model Application Laid-Open No. 63-55733 proposes an electric connection box shown in FIGS. 4 and 5 which has a structure capable of discharging the heat inside the electric connection box to the outside. In the electric junction box 1, the outer peripheral wall 2a of the upper case 2 is bulged outward at a required position, and the intake port 3 and the exhaust port 4 are provided at the end edges of the outer peripheral wall 2a, and the inner periphery of the outer peripheral wall 2a is also provided. A plurality of ribs 2b protruding in a zigzag manner from the surface are provided. The electrical junction box 1 is provided with the ribs 2b so that the upper case 2 and the lower case 5 are engaged with each other, and between the inner surface of the outer peripheral wall 2a of the upper case 2 and the outer peripheral surface of the lower case 5, the inlet 3 to the outlet 4 are provided. A ventilation path 6 leading to is formed.

[0005]

However, in the electric junction box 1 described above, since the intake port 3 and the exhaust port 4 are only provided on the outer peripheral wall 2a of the case, the electric junction box 1 is heated at a high temperature in an engine room or the like. When installed in an atmosphere, not the cool air but the high-temperature air may flow from the intake port 3 and further heat the inside of the electrical junction box. Further, there is no means for forcibly circulating the air from the intake port 3 to the exhaust port 4 through the housing portion 2c, and the cool air flowing from the lower intake port is discharged to the outside from the upper exhaust port by the chimney effect together with the hot internal air. Since it is only discharged, a reliable heat dissipation effect cannot be obtained. In particular, when the electric junction box 1 is installed in the engine room as described above, if the atmospheric temperature of the engine room is high, heat dissipation due to the chimney effect cannot be expected. Further, since the intake port 3 and the exhaust port 4 are in an open state, there is a possibility that water will be generated from the intake port 3 and the exhaust port 4, and they will be arranged in an area such as an engine room where water may be generated. I can't.

The present invention has been made in view of the above problems, and in particular, in an electric junction box installed in an engine room, the electric heat that can surely radiate the internal heat to the outside without impairing the waterproof performance. It is intended to provide a junction box.

[0007]

In order to achieve the above object, the present invention provides an electric junction box for accommodating electric parts inside a resin case according to claim 1, wherein the case peripheral wall is provided with a gap. With a double wall consisting of an outer wall and an inner wall formed by opening, the inside of the inner wall serves as the electrical component accommodating chamber,
A ventilation slit is formed on the inner wall, while an intake port and an exhaust port are formed on the outer wall, the intake port is connected to an intake duct, and the exhaust port is connected to an exhaust duct, so that electrical components are accommodated by ventilation from the intake duct. Provided is an electrical junction box, which is configured to dissipate heat in a room to an exhaust duct.

When the electric junction box is arranged in the engine room of an automobile, the intake duct is connected to the intake air duct arranged in front of the automobile, and the exhaust duct is connected to an exhaust duct opening in the passenger compartment. ing.
(Claim 2) For example, the intake air duct is connected to the intake air duct for air conditioning in the vehicle, and the exhaust duct is connected to the heating exhaust duct of the air conditioner.

The intake duct and the exhaust duct are preferably attached to the intake port and the exhaust port via waterproof grommets. (Claim 3) Further, it is preferable to attach a heat shield member to the inner surface of the outer wall. (Claim 4)

Further, the ventilation slits provided on the inner wall are formed in a longitudinal direction or a lateral direction with a required space over the entire circumference of the inner wall so that air flowing through the gap between the outer wall and the inner wall is accommodated in the electric component inside the inner wall. It is preferable to ventilate the entire area of the chamber. Furthermore, it is preferable that the intake port and the exhaust port provided in the outer wall are formed at diagonal positions of the opposing outer walls so that the air flows through the entire ventilation passage formed by the gap between the outer wall and the inner wall. The case peripheral wall which is the double wall may be either an upper case or a lower case. When the case has a three-part structure in which the upper case, the lower case and the intermediate case are provided between them, the peripheral wall of the intermediate case is a double wall. The upper wall of the upper case and the lower wall of the lower case, which are the upper and lower walls of the case, are the same as before and are not double walls.

[0011]

According to the electric junction box of the first aspect of the present invention, the air flowing from the intake port of the outer wall through the intake duct passes through the gap between the inner walls, and passes through the ventilation slit of the inner wall. Flow into the exhaust chamber, pass through the exhaust opening of the outer wall through the gap between the ventilation slit and the outer wall, and are discharged from the exhaust duct connected to the exhaust port. Therefore, the heat from the heat-generating components such as the relay and the fuse mounted inside the electric junction box can be surely radiated to the outside. Further, since the ducts are connected to the intake port and the exhaust port, no water will leak from the intake port and the exhaust port into the inside of the electrical junction box, and the waterproof property will not be impaired. Further, since each electric component mounted inside the electric junction box is housed inside the double wall, the thermal influence of the engine can be reduced.

According to the electric connection box of the second aspect, since the intake duct is connected to the intake air duct arranged in front of the vehicle, the air pressure flowing into the intake port is high when the vehicle is running, and the air is opened in the vehicle compartment. The exhaust port side connected to the exhaust duct has a negative pressure, so that the air inside the electrical junction box can be forced to flow from the intake port to the exhaust port.

According to the electric connection box of the third aspect, since the intake duct and the exhaust duct are attached to the intake port and the exhaust port via the waterproof grommet, the inside of the electric connection box can be reliably waterproofed.

According to the electrical junction box of the fourth aspect, since the heat shield member is attached to the inner surface of the outer wall, the heat shield member can reduce the heat transmitted from the engine room into the electrical junction box.

[0015]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 shows an electric connection box according to a first embodiment of the present invention. An electric connection box 10 is composed of a synthetic resin upper case 11 and a lower case 12 which are fitted to each other. Wire harness W / H
A junction box 13, a relay box 14, a fusible link box 15, and an electronic control unit 16 (ECU) such as an electronic fuel injection device (EFI) of the engine are housed and installed in an engine room of an automobile. I am trying to do it.

The upper case 11 is the lower case 1.
2 is provided with a sealing packing 18 on the lower end surface of the outer peripheral wall 11a fitted to the outer peripheral wall 11a, and the packing 1 is provided on the joint end surface of the lower case 12.
When the upper case 11 and the lower case 12 are fixed by locking means (not shown) with 8 interposed, the inside of the case is hermetically sealed for waterproofing.

The lower case 12 has an outer peripheral wall having a double wall structure including an outer wall 12a and an inner wall 12e. Outer wall 1
An insertion hole 12b for introducing the wire harness W / H into the inside, an intake port 12c for supplying the air into the inside, and an exhaust port 12d for discharging the air are provided at required positions of 2a. The intake port 12c and the exhaust port 12d have separate long and tubular cylindrical intake ducts 20 and exhaust ducts 21.
Are linked. Furthermore, the outer wall 12a and the inner wall 12e
A ventilation gap 12p is formed with a required gap between them, and a reinforcing rib 12f is provided to project from the inner surface of the outer wall 12a.

The insertion hole 12b is cut out below the upper edge of the outer wall 12a, and the wire harness W / H is inserted into the lower case 12 through a rubber waterproof grommet 23 in the insertion hole 12b. Have been introduced to. The intake port 12c and the exhaust port 12d are opposed to each other on the outer wall 1 on the long side.
It is formed by cutting out from the upper edge at a position diagonal to 2a, and one end of the intake duct 20 and the exhaust duct 21 is attached through waterproof grommets 24A, 24B.

The inner wall 12e has a bottom surface 12g and an outer wall 12a.
It is provided in parallel with and projecting at a required interval, and inside thereof, an electrical component housing chamber 12h in which the boxes 13, 14, 15 and the electronic control unit 16 are installed is formed. The inner wall 12e is provided with a ventilation slit 12i that is cut out from the vicinity of the upper end to the bottom surface 12g with a required interval all around the circumference so that the air supplied from the intake port 12c can be discharged from the exhaust port 12d through the electrical component housing chamber 12h. I have to. The ventilation slit 12i may be provided at a position facing at least the intake port 12c and the exhaust port 12d of the inner wall 12e. Further, an insertion hole 12k for introducing the wire harness W / H into the electric component housing chamber 12h is provided at a position of the inner wall 12e facing the insertion hole 12b.

The other end of the intake duct 20 is arranged in the engine room of the vehicle. On the other hand, the other end of the exhaust duct 21 is arranged inside a vehicle compartment. In this embodiment, the tip of the intake duct 20 is connected to an intake air duct (not shown) arranged in front of the vehicle in the engine room in order to introduce outside air into the vehicle air conditioner.
On the other hand, the exhaust duct 21 is an exhaust duct arranged on the vehicle interior side that connects the exhaust port of the air conditioner and the air outlet in the vehicle interior.
(Not shown). Therefore, while cold outside air is introduced into the electric junction box 10, the heat discharged from the electric junction box is discharged into the vehicle interior as it is along with warm air from the air conditioner and the heater during heating, while it is discharged from the air conditioner during cooling. The cold air is mixed with the cold air to be discharged into the passenger compartment in a cooled state.

The waterproof grommets 23, 24A, 24B
Is made of rubber and is formed larger than the insertion hole 12b, the intake port 12c, and the exhaust port 12d, and the locking groove 2 formed on the peripheral surface thereof.
3b and 24b are fitted and attached to the peripheral edges of the respective insertion holes.

The electrical connection box 10 is a wire harness W.
/ H and each duct 20, 21, waterproof grommet 2
The upper case 11 is fitted in the upper surface opening of the lower case 12 while being attached to the lower case 12 via 3, 24A, 24B, and the packing 18 attached to the upper case 11 is attached to the upper edge of the outer wall 12a of the lower case 12 and the waterproof grommet. 23, 24A and 24B are closely attached and fixed by a lock means (not shown) to prevent electric water from entering the inside of the electric junction box 10 and assembled.

In the electric junction box 10 having the above-mentioned structure, since the peripheral wall of the lower case 12 has a double wall structure, even if the electric junction box 10 is installed in the engine room, it is directly attached to each part installed in the electric part housing chamber 12h. It is possible to prevent the heat of the engine from being transmitted and reduce the influence of the heat.

On the engine room side where the electric junction box 10 is installed, the pressure becomes high due to the inflow of air, while the vehicle room side where the air does not flow is at a lower pressure than the engine room side. Therefore, the exhaust duct side becomes a negative pressure, and the outside air is sucked from the intake duct 20 arranged in the engine room, and the intake duct 20, the intake port 12c of the outer wall, the ventilation path 12p between the outer wall and the inner wall, and the ventilation slit 12i of the inner wall. Through
Cold outside air is introduced into the electrical component housing chamber 12h. The introduced outside air cools the inside of the electrical component housing chamber 12h.
Further, the hot air that is trapped inside is discharged together with the inflowing air through the ventilation slit 12i, the ventilation passage 12p, the exhaust port 12d, and the exhaust duct 21.

FIG. 2 shows an electric junction box 10 of the second embodiment, which is an outer wall 12a of a lower case 12.
A heat shield member 25 is attached to the inner surface of the engine, and the heat shield member 25 is used to further reduce the influence of the heat of the engine on each component in the electric junction box 10, particularly the ECU 16.

The electric junction box shown in the first and second embodiments is also applied to the electric junction box 10 in which the wire harness W / H is introduced from below the lower case 12 as shown in FIG. You can do it. In this case, an insertion hole 12b 'for introducing the wire harness W / H is provided from the lower end edge of the lower case 12, and the wire harness is inserted into the insertion hole 12b' via the waterproof grommet 23 as in the first embodiment. W / H is attached, and the lower case 12 is covered by the cover 28 having the packing 27 for sealing on the upper end surface.
The lower end of is closed.

[0027]

As is apparent from the above description, in the electric junction box according to claim 1 of the present invention, the inner wall has a double wall structure including an outer wall and an inner wall provided with a peripheral wall of the case spaced apart from each other. It accommodates electrical parts, has an intake port and an exhaust port on the outer wall, and has a cylindrical duct connected from the intake port and the exhaust port, so outside air is introduced from the intake port without impairing waterproofness. The heat inside the electric junction box can be radiated from the exhaust port. Further, since it has a double wall as described above, when the electric junction box is installed in the engine room, the heat effect of the engine can be reduced, and in particular, the overheating of the ECU that may malfunction due to heat is suppressed, It is possible to prevent the ECU from malfunctioning.

In the electric junction box of the present invention, the tip of the intake duct is arranged in the engine room of the vehicle, while the tip of the exhaust duct is arranged in the vehicle compartment. Due to the pressure difference between the side of the vehicle and the side of the vehicle compartment, air can be forced to flow from the intake side to the exhaust side by negative pressure, and heat can be reliably dissipated from the electrical junction box.

In the electric connection box of the third aspect, it is possible to reliably prevent water from entering through the intake port and the exhaust port. In addition, claim 4
In the electric junction box, since the heat shield member is attached to the outer wall of the case, it is possible to further reduce the influence of heat on each electric component installed inside the inner wall.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a heat dissipation structure of an electric junction box according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing a heat dissipation structure of an electrical junction box according to a second embodiment.

FIG. 3 is a perspective view showing an electric connection box configured to introduce a wire harness from below.

FIG. 4 is an exploded perspective view showing a conventional electric junction box configured to be able to discharge heat inside.

FIG. 5 is a perspective view showing a state in which a conventional electric junction box is assembled.

[Explanation of symbols]

 10 Electrical Connection Box 11 Upper Case 12 Lower Case 12a Outer Wall 12b Insertion Hole 12c Intake Port 12d Exhaust Port 12e Inner Wall 12i Ventilation Slit 16 Electronic Control Unit W / H Wire Harness

Claims (4)

[Claims] 1. An electric junction box for accommodating an electric component inside a resin case, wherein the case peripheral wall is a double wall composed of an outer wall and an inner wall formed with a gap, and the inside of the inner wall is the above. An air intake slit is formed on the inner wall of the electrical component storage chamber, while an intake port and an exhaust port are formed on the outer wall, and the intake port is connected to an intake duct, and the exhaust port is connected to an exhaust duct. An electric junction box characterized in that heat from the electric component housing chamber is radiated to an exhaust duct by ventilation from the duct. 2. The electric junction box is arranged in an engine room of an automobile, and the exhaust duct connects the intake duct to an intake air duct arranged in front of the automobile and opens the exhaust duct into a passenger compartment. The electrical junction box according to claim 1, which is connected to the. 3. The electrical junction box according to claim 1, wherein the intake duct and the exhaust duct are attached to the intake port and the exhaust port via waterproof grommets. 4. The electric junction box according to claim 1, further comprising a heat shield member attached to an inner surface of the outer wall.