JPH03235610A - Electrical joint box for automobile - Google Patents

Abstract

PURPOSE:To suppress local overheating of a casing body by composing at least such member of the casing body as mounting a heating parts of a highly heat conductive resin produced by mixing an inorganic material into the resin. CONSTITUTION:Four small capacity fuses 12A, two intermediate capacity fuses 12B and two relays 13 are mounted on a casing body 11 and an upper cover is applied on the parts mounting face side whereas a lower cover 16 is applied on the opposite side. The casing body 11 is made of polyphenylenesulfide mixed with 55wt.% of glass fibers. The casing body has heat conductivity of 1.2kcal/ m.h. Consequently, heat produced from heating parts or at the joint of terminal can be dissipated efficiently resulting in suppression of local overheat of the casing body 11 due to heating parts and suppression of temperature rise in the casing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrical junction box used for in-vehicle wiring of an automobile.

(Prior art) As shown in Figure 7, an electrical junction box for an automobile has electrical parts such as a fuse 12 and a relay 13 mounted inside the case body, and these parts are inserted to form a predetermined circuit. An output wire 14 is connected directly or via a bus bar or connector.A top cover 15 is attached to the component mounting side of the case body 110 for waterproofing and dustproofing.
A lower cover 16 is attached to the wire 14 extraction surface side. Further, the lower case 16 is provided with a wire outlet 17 for drawing the electric wire 14 out of the case.

CI! [Problem] With the increase in the number of automobile electrical components in recent years, the following problems have arisen in the electrical junction box configured as described above. In other words, the size of electrical junction boxes is limited due to the space available for installation, and as the number of electrical components in automobiles increases within these constraints, the number of heat-generating parts such as fuses and relays increases, and the size of electrical junction boxes increases. The density of the connected circuits is also high (in particular, the fusible parts of fuses and the coil parts of relays generate extremely large amounts of heat. For this reason, not only are there many sources of heat generation such as heat-generating parts and terminal connections, but also the amount of heat generated is large. Become.

As a result, there are problems such as localized overheating, which causes melting and deformation of the case body, etc., and heat buildup inside the case, impairing the functions of fuses and relays.

(IllW solution and its effect) In view of the above-mentioned problems, an object of the present invention is to provide an electrical connection box that can suppress local overheating within the case and overall temperature rise. .

In the above-mentioned electrical junction box, one of the paths through which the heat generated inside the case is discharged to the outside of the case is that the heat generated from the heat-generating parts is transmitted to the case, conducts heat through the case, and is discharged to the outside of the case. One possible route is that the substance is released from the outside. Therefore, if the heat flow through this path is increased, the temperature rise within the case can be suppressed. The case of conventional electrical junction boxes is made of a resin material with poor thermal conductivity, and it cannot be said that the heat dissipation properties of this route are necessarily utilized.

Therefore, the invention of claim 1 provides an electrical connection box for an automobile in which heat-generating parts such as fuses and relays are housed in a case, in which the case body in which at least the heat-generating parts are mounted among the members constituting the case is made of resin. It is characterized by being made of a highly thermally conductive resin material whose thermal conductivity is increased by mixing an inorganic mixed material with.

In this way, the heat generated from heat generating parts and terminal connections can be efficiently diffused to other parts, suppressing local overheating of the case body due to heat generating parts, etc., and improving heat dissipation to the outside through the case body. As a result, the temperature rise inside the case can be suppressed.

Further, the invention of claim 2 provides an electrical junction box for an automobile in which a heat generating component such as a fuse or a relay is housed in a case, in which at least one of the members constituting the case is placed over the heat generating component mounting surface of the case body. A contact piece that contacts the heat-generating component is formed on the inner surface of the cover member, and the cover member is made of a highly thermally conductive resin material that has increased thermal conductivity by mixing resin with an inorganic mixture. .

In this way, the heat of the heat generating components is diffused and dissipated through the cover member, and it is possible to suppress local temperature rises and overall temperature rises within the case.

Furthermore, the invention of claim 3 provides an electrical connection box for an automobile in which heat generating parts such as fuses and relays are housed in a case, in which heat dissipation fins are formed on the outer surface of at least some of the members constituting the case. In addition, the member on which the radiation fins are formed is made of a highly thermally conductive resin material in which thermal conductivity is increased by mixing resin with an inorganic mixture.

In this way, the radiation fins improve heat radiation from the outer surface of the case, and the member on which the radiation fins are formed has good thermal conductivity, so it is possible to suppress a rise in temperature inside the case.

Moreover, if two or more of the inventions of claims 1 to 3 are combined, it goes without saying that the temperature rise suppressing effect can be further enhanced.

The highly thermally conductive resin material used in the present invention is a mixture of a thermoplastic or thermosetting resin and a large amount of an inorganic mixture. It is common practice to mix glass fiber with resin, but this is done to improve strength and moldability, and the amount of glass fiber mixed is at most 30 to 4 Qwt%.
However, this level has no substantial effect on improving thermal conductivity.

When a large amount (50 wt% or more) of glass fiber is mixed with polyphenylene sulfide, polyethylene terephthalate, or polybutylene terephthalate, which are resins with relatively excellent thermal conductivity, the thermal conductivity improves and the material becomes a material that can be used in the present invention.

Also alumina (AI□03), magnesia (MgO)
, oxides such as zirconia (ZrOg), herylia (Bed), aluminum nitride (AIN), boron nitride (
If a powder of a nitride such as BN) or a carbide such as silicon carbide (SiC) is mixed with a resin, the thermal conductivity will be significantly increased, and the material can be used in the present invention. In particular, a mixture of the above-mentioned resin such as polyphenylene sulfide with these inorganic powders, or a mixture of these inorganic powders and glass fiber is a suitable material for the present invention.

These highly thermally conductive resin materials have electrical insulation properties and can be molded in the same manner as conventional case resin materials.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the invention of claim 1 will be explained in detail. As shown in Figure 1, four small capacity fuses 12A are installed in the case body 11.
In an electrical junction box with a structure in which two medium capacity fuses 12B and two relays 13 are mounted, an upper cover 15 is placed on the component mounting side and a lower cover 16 is placed on the opposite side, the case body 11 is installed as follows. Made of material. Note that the upper cover 15
The lower cover 16 is made of nylon 66 as in the conventional case.

Example 1 55-t% glass fiber in polyphenylene sulfide
Contaminated. Thermal conductivity is 1.2 cal/mh・℃
It is.

Example 2 45w of alumina powder in polybutylene terephthalate
Contains L%. Thermal conductivity is 2.6 Kcal/m・
It is h・℃.

Example 3 Polyphenylene sulfide mixed with 30 wt% glass fiber and 30 wt% aluminum nitride powder.

The thermal conductivity is 3.1 Kcal/m-h·°C.

Comparative example 1 (conventional product) Nylon 66° thermal conductivity is 0.20 cal/m -h
−℃.

Comparative Example 2 Polybutylene terephthalate. Thermal conductivity is 0.25Kc
al/m−h・℃.

When we measured the temperature rise in each part of these electrical junction boxes by applying a prescribed current, the maximum temperature rise at the component connection terminals and the maximum temperature rise in the space inside the electrical junction box is shown in Table 1.
It was as shown in .

Table 1 As is clear from Table 1, by forming the case body from a highly thermally conductive resin material, the local temperature rise and the temperature rise within the box can be suppressed to a low level.

Next, as shown in Figure 2, four screw-tight type medium capacity fuses 12C were attached to the case body 11 housing the busper 18, the electric wires 14 were connected, and the upper cover 15 and lower cover 16 were covered. In the electrical junction box of the structure,
The case body 11 was made of the following material. Note that the upper cover 15 and the lower cover 16 were made of nylon 66.

Example 4 A phenolic resin mixed with 20-t% glass fiber and 25@t% alumina powder. Thermal conductivity is 2.1 Kca
l/mh・℃.

Comparative Example 3 (Conventional product) Phenol resin. Thermal conductivity is 0.28Xcal/m,
−h・℃.

Table 2 shows the results of the same tests as above for these electrical connection boxes.

Table 2 From the above Examples and Comparative Examples, it can be said that it is desirable that the highly thermally conductive resin material used for the case body has a thermal conductivity of IKcal/m-h·°C or more.

It is clear that if such a highly thermally conductive resin material is also used for the cover member of the case, the heat dissipation will be further improved.

Next, an embodiment of the invention according to claim 2 will be described with reference to FIGS. 3 and 4. This electrical connection box consists of case body 11
In the case where the relay 13 is mounted on the top cover 15 and the top cover 15 is covered, a contact piece 19 that contacts the head of the relay 13 is formed on the inner surface of the top cover 15, and the top cover 15 is made of a high heat conductive material as described above. It is unique in that it is made of a synthetic resin material.

In this way, the heat of the relay 13 is efficiently dissipated to the outside through the upper cover 15, and the temperature rise of the relay 13 and the temperature rise inside the box can be suppressed to a low level. Furthermore, if the case body 11 is also made of a highly thermally conductive resin material,
Furthermore, thermal diffusivity and heat dissipation are improved.

FIG. 5(al(b)) shows another embodiment of the invention of claim 2.This electrical connection box has a contact piece 19 that contacts the side surface of the relay on the inner surface of the upper cover 15, and The cover 15 is made of a highly thermally conductive resin material.Although only the upper cover is shown in FIG. 5, the structure of the case body side is the same as that of the previous embodiment.

Even in this case, the same effects as in the above embodiment can be obtained.

Next, an embodiment of the invention according to claim 3 will be described with reference to FIG. This electrical junction box has heat generating parts (not shown) such as fuses and relays mounted on a case body 11 and is covered with an upper cover 15. In addition, the case body 11 and the upper cover IS are formed of the above-mentioned highly thermally conductive resin material.

In this way, the heat dissipation fins 20 cause the case body 11 to
Moreover, the heat dissipation of the upper cover 15 is improved, and the temperature rise inside the box can be suppressed. Furthermore, since the case body 11 is made of a highly thermally conductive resin material, it has good thermal diffusivity and has the effect of suppressing local overheating. Further, if a contact piece is formed on the inner surface of the upper cover 15 to contact the heat generating component, heat dissipation performance is further improved.

〔Effect of the invention〕

As explained above, according to the invention of claim 1, the heat generated from the heat-generating parts etc. can be diffused better, the case body can be prevented from becoming locally overripe, and the heat dissipation to the outside through the case body can be improved. Since the temperature is also good, there is an effect of suppressing the temperature rise inside the case.

Further, according to the invention of claim 2, the heat of the heat generating component is diffused and dissipated through the cover member, so there is an effect that local temperature rise and temperature rise within the case can be suppressed.

Further, according to the third aspect of the present invention, the heat conductivity of the case member on which the radiation fins are formed is improved, and the heat dissipation from the outer surface of the case member is increased, so that it is possible to suppress the temperature rise inside the case.

[Brief explanation of drawings]

Figure 1 is a perspective view showing one embodiment of the invention of claim 1;
2 is a perspective view showing another embodiment, FIG. 3 and FIG.
4 is a perspective view and a sectional view showing one embodiment of the invention of claim 2, FIG. 5(a) is a bottom view of the upper cover portion similarly showing another embodiment, and FIG. V line sectional view,
Figure 6 is a perspective view showing an embodiment of the invention of claim 3;
7 is a perspective view showing a conventional electrical connection box. 11: Case body 12. 12A ~ 12c: Fuse 1
3: Relay 14: Electric wire 15: Upper cover 16: Lower cover 18: Bus bar 19: Contact piece 20; Radiation fin figure - 1 Figure - Figure - 6 Figure -

Claims (1)

[Claims] 1. In an electrical junction box for an automobile in which heat-generating parts such as fuses and relays are housed in the case, the case body in which at least the heat-generating parts are mounted among the members constituting the case is made of resin. An electrical junction box for an automobile, characterized in that it is made of a highly thermally conductive resin material whose thermal conductivity is increased by mixing an inorganic mixture with a resin material. 2. In an automotive electrical junction box in which heat-generating components such as fuses and relays are housed in the case, heat is generated on the inner surface of at least the cover member that covers the heat-generating component mounting surface of the case body among the members that make up the case. An electrical connection box for an automobile, characterized in that a contact piece that comes into contact with a component is formed, and a cover member thereof is made of a highly thermally conductive resin material whose thermal conductivity is increased by mixing resin with an inorganic mixture. 3. In an electrical junction box for an automobile in which heat generating parts such as fuses and relays are housed in the case, heat radiation fins are formed on the outer surface of at least some of the members constituting the case, and the heat radiation fins are An electrical connection box for an automobile, characterized in that the formed member is made of a highly thermally conductive resin material whose thermal conductivity is increased by mixing resin with an inorganic mixture.