JPH0898374A - Forming method for water-proof block in wire harness - Google Patents

Abstract

PURPOSE: To form a tightly sealed water-proof block, by bending a wire harness partly with a tolerance sufficient for relative dislocation of wires, forming a gap between the wires using a tightening member put on both sides of the bent part, and hardening a resin after the bent part is set in a die and the gap between wires is impregnated with a liquid resin. CONSTITUTION: A part of an elongated wire harness is bent in a way that an outer wire has a larger circumferential diameter than an inner one, and a tightening member 19 is turned on both sides of the bent part. After that, the bent part is stretched again to form a gap between wires 13. The part of wires 13 with a gap is set between dies 23A and 23B, and an aqueous resin is injected and hardened. In this way, the tightly sealed water-proof block is formed at low cost without troublesome work by making a gap 21 between the wires 13 and impregnating the gap 21 with the liquid resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a waterproof block on a part of a wire harness.

[0002]

2. Description of the Related Art A wire harness is a bundle of a large number of electric wires and a connector or the like is attached to the end of each electric wire, and is used for wiring inside a vehicle. For example, in the portion where the wire harness penetrates the wall between the interior of the car and the engine room, water that has been scattered or condensed in the engine room enters the room through the hole for inserting the wire harness in the wall. There is a risk. Therefore, conventionally, a rubber grommet is attached to the outer periphery of the wire harness, and the outer peripheral portion of the grommet is attached to the edge of the hole to close the opening around the wire harness. However, in the wire harness, there are narrow gaps extending in the longitudinal direction between the electric wires, and water passes through these gaps. Therefore, simply attaching a grommet is not sufficient for waterproofness.

[0003]

Therefore, a wire harness with a waterproof block in which resin is filled in the wire harness to close the gap between the electric wires has been studied (Japanese Utility Model Publication No. 61-93939, etc.). However, since the wire harness is a bundle of many wires aligned in the same direction, adjacent wires are in contact with each other in the longitudinal direction,
It is extremely difficult to fully fill the resin to the internal gap. One solution to this problem is to attach a ring to each electric wire in the portion filled with resin to form a gap between the electric wires (Japanese Utility Model Publication No. 64-58223).
In addition, bending a wire of a portion to be filled with resin one by one to make a gap between wires (Japanese Utility Model Laid-Open No. 1-58222).
Although such a method has been proposed, there is a drawback that such a method is troublesome and the cost is high.

In view of the above problems, an object of the present invention is to provide a method for forming a waterproof block for a wire harness, which is capable of forming a gap between electric wires by a simple method and allowing resin to sufficiently penetrate into the inside. To do.

[0005]

In order to achieve this object, the present invention provides a part of a wire harness formed by bundling a plurality of electric wires in the longitudinal direction in a state where relative displacement between the electric wires is allowed. Bend and wrap around the wire harness on both sides of the bent part with a tightening member that prevents relative displacement of the wires, and then extend the bend of the bent part of the wire harness, thereby bending the wire between the tightening members. Sometimes the one that was located outside the inside of the bend creates a greater slack and creates a gap between the wires, and between the tightening members, set the wire harness part where there is a gap between the wires in the mold, The mold is filled with a liquid resin material, and the liquid resin material is cured in a state where the liquid resin material penetrates into the gap between the electric wires to form a waterproof block (contract). Section 1).

With this arrangement, it is possible to form a gap between a large number of electric wires constituting the wire harness at a time, and the liquid resin material for forming the waterproof block can be sufficiently penetrated into the gap. , It becomes possible to easily form a waterproof block with excellent watertightness.

Further, in the method of the present invention, when a part of the wire harness in the longitudinal direction is bent, it is preferable to use a bending jig having a wire harness guide groove whose groove width becomes narrower toward the inner side of the groove ( Claim 2).

When such a bending jig is used, the electric wire located on the inner side of the bending can be bent with a smaller bending diameter.
The difference between the perimeter of the wire located inside the bend and the perimeter of the wire located outside the bend increases, and when the bend of the wire harness is extended, the gap between the wires can be increased and It becomes easy to disperse the gaps evenly in the cross section of the wire harness.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. As shown in FIGS. 1A and 1B, the wire harness 11 is a bundle of a large number of electric wires 13 aligned in the same direction. In order to form a waterproof block on a part of the wire harness 11 in the longitudinal direction, in the method of the present invention, first, the waterproof block forming portion of the wire harness 11 is bent by being applied to a bending jig 15 as shown in FIGS. To do. This bending is performed in a state in which relative displacement between the electric wires 13 is allowed (in a state where no tape or the like is wound around the outer periphery of the wire harness).

The bending jig 15 includes upper and lower guide pieces 16a,
Between 16b, it has the guide groove 17 which controls the bending diameter of the wire harness 11. When the wire harness 11 is bent along the guide groove 17, the electric wire 13a located inside the bend is more than the electric wire 13b located outside the bend.
Has a longer circumference at the bent portion.

As shown in FIG. 3, the guide groove 17 in this embodiment is formed so that the width becomes narrower as it goes deeper into the groove. If the guide groove 17 has such a shape,
Since the electric wire 13a located inside the bend enters the inner part of the guide groove 17 and is bent with a smaller bending diameter, the electric wire 13a is located inside the bend more than when the entire wire harness 11 is bent with a substantially circular cross section. The difference between the perimeter of the electric wire 13a and the perimeter of the electric wire 13b located outside the bend becomes large. This is effective in increasing the gap between the electric wires described later.

After bending the wire harness 11 as described above, a tightening member 19 for preventing relative displacement between the electric wires 13 is wound around the wire harness 11 on both sides of the bent portion as shown in FIG. A normal adhesive tape or the like may be used as the fastening member 19.

After that, when the wire harness 11 is taken out of the bending jig 15 and the bending of the bending portion is extended, the result is as shown in FIG. 5, and the electric wire 13 between the fastening members 19 is located outside the bending when bending. The greater the degree of slack, the more the gap 21 is formed between the electric wires 13. The size of the gap 21 increases as the difference between the perimeter of the electric wire 13a located inside the bend and the perimeter of the electric wire 13b located outside the bend increases.

Next, the wire 13 of the wire harness 11
As shown in FIG. 6, the part where the gap 21 is formed is RI
It is installed between the two split dies 23A and 23B for M (reaction injection molding). In this embodiment, the molds 23A and 23B are
Coil spring 27 in packing holders 25A and 25B
It is movably supported via A and 27B. The packing holders 25A and 25B fix and support the packings 29A and 29B that seal the both ends of the molds 23A and 23B.

Next, the packing holder 29A on the upper side is lowered, and as shown in FIGS. 7 and 8, the molds 23A and 23B are formed.
And then lowering the upper packing holder 29A further, and packing 2 as shown in FIG. 9 and FIG.
Close 9A and 29B. Packing 29A,
If 29B is to be closed later, the molds 23A, 23
When B is closed, it is possible to confirm whether or not the molds 23A and 23B are correctly closed.

This is because, for example, when closing the dies 23A and 23B, some of the electric wires 13 may be caught between them and cannot be closed accurately. If injection is performed, resin leakage will occur, and in any case defective products will be produced. Therefore, it is extremely important to be able to confirm whether or not the molds 23A and 23B are correctly closed when they are lightly closed.

Packing 29 as shown in FIGS. 9 and 10.
When A and 29B are closed, packing holders 29A and 2A
The coil springs 27A and 27B are compressed by 9B, and the molds 23A and 23B are clamped (mold clamping).

The packing 29A, 29B is a mold 23.
Tighten the wire harness 11 at both ends of A and 23B,
The resin is sealed so as not to leak. The material of the packings 29A and 29B is elastic rubber. As shown in FIG. 10, the holes 31 for tightening the wire harness 11 of the packings 29A and 29B have the dies 23A and 23B.
Is eccentric upward with respect to the hole 33 formed on the inner surface of the. This is the mold 23A, 23B when resin is injected
This is for facilitating the discharge of the internal air to the outside through the gap between the electric wires 13 and preventing the lowermost bulged portion of the electric wire 13 from coming into contact with the inner surface of the lower mold 23B.

The joint 35 (see FIG. 10) of the upper and lower packings 29A and 29B has a "C" shape. In this manner, there is an advantage that the wire harness can be well tightened even near the joint 35 with the packings 29A and 29B tightened from above and below.

Further, the tightening member 19 and the packing 29A,
The positional relationship of 29B is also important. The inner end of the tightening member 19 is located inside the inner surfaces of the packings 29A and 29B (the mold 23
A, 23B), it becomes difficult for the air in the mold to be exhausted, and air bubbles easily remain in the molded waterproof block. Further, if the inner end of the fastening member 19 is located outside the outer surfaces of the packings 29A and 29B, resin leakage is likely to occur. Therefore, it is preferable that the inner end of the tightening member 19 be positioned within the range of the thickness of the packings 29A and 29B as shown in FIG.

Therefore, at the stage of FIG.
It is necessary to predetermine the winding position of (1) so that the bending state of the wire harness is extended as shown in FIG. The tightening member 19 is also effective in reducing the gap between the electric wires 13 therein, increasing the internal pressure of the injected resin in the mold, and sufficiently penetrating the resin into the gap 21 between the electric wires in the mold. .

Packing 29 as shown in FIGS. 9 and 10.
If A and 29B are closed, then molds 29A and 29B
Liquid resin material is injected into B. As the liquid resin material, for example, a two-liquid mixed type urethane resin or the like is used. Since there is a gap 21 between the electric wires 13, the liquid resin material penetrates into the interior through the gap 21 and causes a curing reaction to be cured. When the molds 23A and 23B are opened after curing, as shown in FIG.
1 and the waterproof block 37 as shown in FIG. 12 is obtained.

The waterproof block 37 thus obtained has high water-tightness because the resin is filled even in the gaps between the electric wires 13. A grommet 39 is attached to the outer periphery of the waterproof block 37 as shown by the alternate long and short dash line, and is used, for example, to seal a hole in a wall between an interior of an automobile and an engine room.

The above is one embodiment of the present invention, and the present invention is not limited to this. For example, waterproof block 3
It is also possible to form 7 integrally with the grommet 39.

Further, when the liquid resin material is injected into the mold, in order to easily discharge the air in the mold and reduce the bubbles, as shown in FIG. 13, the exhaust hole 4 is formed in the upper mold 23A.
1 or molds 23A, 2 as shown in FIG.
The taper surfaces 43 are formed on both ends of the inner surface of 3B, and the mold 2
It is also possible to adopt means such as installing the 3A and 23B at an angle.

Further, as shown in FIG. 15, when the lowermost bulging portion of the electric wire 13 comes into contact with the inner surface of the lower mold 23B and the flow of the liquid resin material may be delayed, the lower mold 23A is formed. It is desirable to form a circumferential groove 45 on the inner surface of the so as to make the flow of the liquid resin material smooth.

[0027]

As described above, according to the present invention, a gap is collectively formed between a large number of electric wires forming a wire harness, and a liquid resin material is allowed to penetrate into the gap to form a waterproof block. Therefore, it is possible to form a waterproof block having high watertightness at a low cost without trouble.

[Brief description of drawings]

FIG. 1 is a front view showing a main part of a wire harness, and FIG.

FIG. 2 is a front view showing a state in which the wire harness is bent at the first stage of the embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG.

FIG. 4 is a front view showing a state in which a tightening member is wound around the wire harness in the next stage of FIG.

FIG. 5 is a front view showing a state where the bending of the wire harness is extended in the next stage of FIG.

FIG. 6 is a cross-sectional view showing a state where the waterproof block forming portion of the wire harness is installed between the molds at the next stage of FIG.

FIG. 7 is a cross-sectional view showing a state where the mold is lightly closed in the next stage of FIG.

FIG. 8 is a sectional view taken along line BB in FIG.

9 is a cross-sectional view showing a state in which packing is closed in the next stage of FIG. 7.

FIG. 10 is a side view showing the positional relationship between the mold and packing in the state of FIG.

FIG. 11 is a front view showing a waterproof block formed according to an embodiment of the present invention.

FIG. 12 is a sectional view taken along line CC in FIG. 11;

FIG. 13 is a cross-sectional view showing another example of the mold used in the present invention.

FIG. 14 is a sectional view showing still another example of a mold used in the present invention.

FIG. 15 is a sectional view showing still another example of a mold used in the present invention.

[Explanation of symbols]

11: wire harness 13: electric wire 15: bending jig 17: groove 19: tightening member 21: gap 23A, 22B: mold 29A, 29
B: Packing 37: Waterproof block

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norihide Sakai 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Within Furukawa Electric Co., Ltd. (72) Inventor, Kazuhiko Asami, 380, Takase, Toyosato-cho, Shiga Prefecture Omi Electric Cable Incorporated (72) Inventor Masaaki Baba 380 Takase, Toyogo-cho, Inugami-gun, Shiga Omi Electric Cable Co., Ltd. (72) Inventor Hiroshi Iwaizumi 380, Takase, Inoue-gun, Shiga Prefecture In Omi Electric Cable (72) Inventor Takashi Sudani 380 Takanose, Toyosato-cho, Inoue-gun, Shiga Prefecture Omi Electric Cable Co., Ltd.

Claims (2)

[Claims] 1. A wire harness formed by bundling a plurality of electric wires in a longitudinal direction is bent in a state in which relative deviation between the electric wires is allowed, and the wire harnesses are attached to the wire harnesses on both sides of the bent portion. Wrap the tightening member that prevents the slippage, and then extend the bending of the bent part of the wire harness, so that the wires between the tightening members will be more loosened when they are located outside the inside of the bend when bent. hand,
Make a gap between the electric wires, set the wire harness part between the tightening members where there is a gap between the electric wires in the mold, fill the mold with a liquid resin material, and insert the liquid resin material between the wires. A method of forming a waterproof block for a wire harness, characterized in that the waterproof block is formed by being hardened while being infiltrated into the gap. 2. A bending jig having a wire harness guide groove having a groove width narrower toward a depth of the groove when bending a part of the wire harness in the longitudinal direction. Method of forming waterproof block for wire harness.