JP2904363B2 - Method of forming protective layer on wire joint and structure of wire joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention, when combining multiple insulated wire, a method for forming a protective layer on the coupling portion and
The present invention relates to a structure of an electric wire joint .

[0002]

2. Description of the Related Art Two or more insulated wires are connected to each other and a protective layer is formed at the connection portion.
A technique described in Japanese Patent No. 49226 has been proposed. As shown in FIG. 2 (A), first, as shown in FIG. 2 (A), the insulating coating of the portion of the trunk line 1A and the branch lines 1B, 1C which are to be insulated is to be peeled off, thereby exposing the conductors 2A, 2B, 2C. The conductors are overlapped with each other, the joint terminal 3 is put thereon and crimped (FIG. 2B), and thereafter, the portion from the wire joint 4 to the insulating coating near both sides is covered with a waterproof cover 5 (FIG. 2C), and a tape 6 is wound from above. , And protects the electric wire connection portion 4 through the waterproof cover 5 (FIG. 2D).

[0003] However, in the above-mentioned conventional example, adhesive butyl rubber or the like is used as the waterproof cover 5, but since these materials are generally high in hardness, there is a problem that sufficient waterproofness cannot be obtained. there were. Further, the heat resistance temperature of butyl rubber is about 100 ° C., and it cannot be used in high-temperature places such as an engine room of an automobile.

As another conventional example, Japanese Patent Publication No. 2-134
Japanese Patent No. 30 proposes a technique using a photocurable resin. In this method, a transparent tube is attached and fixed to a joint portion of an electric wire, a photocurable resin is filled between the tube and the electric wire, and then the resin is cured by irradiating light from outside the tube. According to this method, a protective layer without a gap can be formed, and the waterproofness is also improved as compared with the above-described one.

[0005]

However, in the above-mentioned technology, most of the photo-curable resins which can be used at present are urethane resins and PMMA, and in any case, the resin is hard and lacks flexibility. . Therefore, when a thermal shock such as a thermal cycle is applied, the joint may be peeled off due to a difference in the thermal expansion coefficient of the joint. Regarding heat resistance, about 80 ° C. for urethane-based
However, it is at most about 130 ° C., and is not heat-resistant enough to be used in an engine room of an automobile. further,
In the case of a photocurable resin, it is difficult to cure the resin uniformly because of the light transmittance of the resin, and a special device is required for curing.

[0006] In addition, there is a method in which a protective layer is formed at the wire connection portion with a curable resin by a molding method or the like. However, the problems of peeling of the bonded portion and heat resistance are the same as those of the photocurable resin. .

[0007] The present invention has been made to solve the above-mentioned problem, and has such a size that no gap is formed between the electric wire and the joint cover.
Highly flexible has low hardness whenever high heat resistance temperature, yet does not require special equipment for curing silicone
It is an object of the present invention to provide a structure of a wire joint having a gel layer and a method of forming a protective layer on the wire joint.

[0008]

Method of forming the protective layer of the present invention in order to achieve the above objects a solution to the means for] is a coupling portion connecting a plurality of insulated wire, from the outside includes an insulating cover portion near the joint covered with a cover, injecting a liquid silicone resin between said joint cover and wires, prior to cure
No gap between joint cover and electric wire
It has a configuration that form a silicone gel layer with flexibility and tack.

[0009] The structure of the electric wire connecting portion includes a connecting portion to which a plurality of insulated wires are connected, a joint cover covering from the connecting portion to a nearby insulating coating portion, An electric wire and the joint cable
Flexibility and adhesion without gaps between bars and wires
And a silicone gel layer having

[0010]

In the plurality of insulated wires, the insulating coating is removed from the portions to be joined, respectively, to expose the conductor. Then, the parts to be joined are overlapped and put together, covered with a joint terminal and joined by crimping. The joint formed in this way and the insulating coating near the joint are covered with a joint cover, a liquid silicone resin is injected between the joint cover and the electric wire, a crosslinking reaction is caused, and the silicone gel is cured. Since the silicone gel layer is sticking with a strong force to both the wire and the joint cover is flexible, the joint
No cracking occurs even if the flakes peel off or there is a difference in the coefficient of thermal expansion, and the waterproof performance does not decrease. Also, since it is a silicone gel, it can be used in a wide range from high to low temperatures.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. A plurality of electric wires 1A and 1 shown in FIGS. 1 (A) and 1 (B)
B and 1C are the same as described in the conventional example shown in FIG.
The insulating coating of the joint portion is peeled off, the conductors 2A, 2B, and 2C are exposed. Then, the cover 7 covers from the insulating coating portion below the joining portion 4 to the insulating coating portion above the joining portion 4. This cover 7
Is formed with a bottom portion 7c which fits snugly on the main line 1A via a tapered portion 7b below a cylindrical main body portion 7a, and is preferably made of a resin material having some flexibility. .

The upper end of the cover 7 is connected to the electric wires 1A, 1B, 1C.
And a liquid silicone resin 8 (eg, SE189, manufactured by Dow Corning Toray)
0A / B) is injected. The cover 4 and the electric wires 1A, 1B,
When left at room temperature, the liquid silicone resin 8 filled in between 1C and 1C undergoes a cross-linking reaction and cures to form a silicone gel (or silicone gel layer) 8 '. That is, no special device for curing is required.

Since the silicone gel (layer) 8 'is flexible and has high adhesive strength, it adheres firmly to both the wires 1A, 1B, 1C and the inside of the cover 4, and does not easily peel off. The heat resistant temperature is about 200 ° C, and the cold resistant temperature is about -8.
It is as wide as 0 ° C. and does not peel off due to a difference in expansion coefficient even when subjected to a thermal shock (−30 ° C. to 120 ° C.). Furthermore, since the crosslinking reaction is an addition reaction type, there is no reaction by-product,
No need to worry about corroding metal.

[0014]

As described above, according to the present invention, since the silicone gel shop is rich in flexibility and strongly adheres to both the electric wire and the cover, a gap is created even when subjected to a thermal shock or the like.
There is no fraying or peeling, and a highly reliable waterproof function can be obtained. Further, after the injection, if the resin is left at room temperature, it cures even at a low temperature, so that a special device for curing is not required, productivity is improved, and mechanization is possible.

[Brief description of the drawings]

1A and 1B are diagrams showing a protective layer of a wire joint according to the present invention, wherein FIG. 1A is a perspective view and FIG. 1B is a longitudinal sectional view.

FIGS. 2A to 2D are perspective views showing a conventional method for forming a protective layer in the order of steps.

[Explanation of symbols]

 1A, 1B, 1C Insulated wire 2A, 2B, 2C Conductor 4 Joint 7 Joint cover 8 Liquid silicone resin 8 'Silicone gel

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01R 43/00 H01R 4/70 H01R 4/22

Claims (2)

(57) [Claims] The method according to claim 1 binding portion connecting a plurality of insulated wire, covered with the joint cover from the outside includes an insulating cover portion in the vicinity, it injected liquid silicone resin between said joint cover and wires, cured The joint cover
Flexibility and adhesiveness without gaps between
A method of forming a protective layer on the wire connecting portion, characterized that you form a silicone gel layer with. 2. A joint portion to which a plurality of insulated wires are connected, a joint cover covering from the joined portion to a nearby insulated cover portion, and a joint cover between the joint cover and the wires.
Formed and between the joint cover and the wire
A structure of an electric wire connection part comprising a silicone gel layer having flexibility and adhesiveness with no gap .