JPH10224960A - Waterproof structure of grommet for passing wire harness and its formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance waterproof performance by eliminating a gap even when a water stopping agent filling a wire group being passed through a grommet flows away. SOLUTION: When a wire group W is wired at the time of assembling a harness, the wire group is arranged in a row at the part subjected to inter-wire waterproofing and coated with a water stopping agent 25 having required viscosity such that the water stopping agent 25 permeates between the wires. Subsequently, the part coated with the water stopping agent 25 is applied with a sheet 23 of independently foamable material having elasticity and rounded before being inserted into the grommet 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof structure for a grommet mounted with a wire harness inserted into a panel through hole of an automobile, and a method of forming the waterproof structure.

[0002]

2. Description of the Related Art In a wiring harness for an automobile, when wiring the wiring harness through a panel or the like that separates an engine room and a vehicle compartment of a vehicle, a rubber grommet is attached to a through hole formed in the panel and the grommet is passed through the grommet. The wiring harness is wired to prevent water from entering the cabin.

The grommet has a panel engaging portion provided on an outer peripheral surface of an enlarged portion having a substantially conical cylindrical shape, and the panel engaging portion is engaged with an inner peripheral edge of the panel through-hole. The gap is securely sealed for waterproofing, and the wire harness is passed through the grommet to the reduced diameter tube portion extending to the reduced end side of the enlarged diameter portion.

[0004] If there are gaps between the electric wires of the wire harness through which the grommet is inserted and between the electric wires and the grommet tube, water is generated in the vehicle interior from the engine room side through the gaps. Need to be sealed.

As the waterproof structure between lines, as shown in FIG.
Is provided to infiltrate each gap of the electric wire w. Alternatively, as shown in FIG. 6, an elastic cap having a plurality of holes through which each electric wire of the wire harness is inserted one by one is used, and the elastic cap is attached to the elastic cap with the electric wires passed through the holes. There is also provided one that is fitted with a fluid sealing material from the enlarged diameter portion side to the inside of the elastic cap. (Japanese Utility Model Laid-Open No. 1-66713, Japanese Utility Model Laid-Open No. 2-115221, Japanese Utility Model Laid-open No. 4-23)
No. 812)

[0006]

In the case of the former waterproof structure shown in FIG. 5, unless the fluid sealing material has a low viscosity (for example, 100 poise or less), it hardly penetrates into the gaps between the electric wires, and conversely has a low viscosity. In this case, complete waterproofing cannot be expected because there is a possibility that the water will flow out of each gap until the resin is cured. Therefore, generally, a grommet is attached to a predetermined position of the wire harness W / H as shown in FIG. 6 by using a low-viscosity two-component urethane (two-component epoxy, two-component silicon, or the like). 1 is filled while mixing a two-part urethane or the like, and then dried and cured after filling.

However, it is troublesome to use a mixture of two liquids such as two-part urethane, and the liquids mixed at one time are easily cured in the air.
Very difficult to handle. In addition, there is a problem in that the equipment for mixing the two liquids is large-sized and cannot be operated on a wire harness assembly line, and a separate process must be provided to fill the sealant.

On the other hand, in the latter waterproof structure, since a gap is reliably formed between the electric wires, even if the fluid sealing material has a high viscosity, it can easily penetrate into the gap between the electric wires to achieve perfect waterproofing. In addition, a separate elastic cap is required, and the number of steps for inserting each electric wire through the cap and the step of fitting the cap to the grommet are increased. In addition, there is a problem that the diameter of the enlarged portion of the grommet is increased by an amount corresponding to the gap between the electric wires, and the grommet is enlarged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the process is relatively simple and the cost is small.
An object of the present invention is to provide a waterproof structure and a waterproof structure method of a wire harness that can be completely waterproofed.

[0010]

According to a first aspect of the present invention, there is provided a waterproof structure for a grommet mounted in a panel through hole with a wire harness inserted therein. The waterproofing agent is filled between the wires inserted into the grommet, and the outer periphery of the wire group filled with the waterproofing agent is wrapped with a sheet made of an elastic foam having a closed cell shape having elasticity. A waterproof structure of a grommet in which a wire harness is inserted is provided, in which a sheet of a foam material is adhered to an inner wall of a grommet.

The above-mentioned elastic foam having a closed cell shape is impervious to air and water.

[0012] The waterproof structure of the wire harness according to the first aspect is formed by the method according to the third aspect.
That is, when laying the electric wire group at the time of assembling the harness, the electric wire group of the part to be waterproofed between the lines is adjacently arranged in a row, and a water stop having a required viscosity with respect to the parallel electric wire group. An agent is applied so as to penetrate between the electric wires, and then a portion of the waterproofing agent applied is covered with an elastic foam material sheet, rounded into a circular section, and passed through the grommet.

As described above, when wires are arranged on the wire harness assembly line at the time of wiring, and a group of wires in this state is coated with a water-stopping agent having a required viscosity, the surface of each wire can be securely applied. A waterproofing agent is applied to
When applied so as to penetrate into the gaps between the electric wires, the waterproofing agent can be surely applied to the surfaces of the electric wires and between the electric wires. afterwards,
When an electric foam sheet having elasticity is put on these electric wire groups and taken out, the electric wire groups are taken out without attaching the waterproofing agent to the hands of the workers, and are arranged in a line from the foam material sheet on the front side. Can be easily rounded into a circular cross section, and the flow and diffusion of the water stopping agent can be prevented to some extent.

However, after the foamed material sheet is rolled, it is attached through a grommet. However, usually, in order to speed up the working process, the work for mounting the grommet is performed while the waterproofing agent is not completely cured. Is performed. At this time, the reduced diameter portion of the grommet is pushed and spread, and after the grommet is inserted, the contraction force of the grommet is applied to the waterproofing agent, so that the waterproofing agent easily flows in the axial direction. When the waterproofing agent flows,
The outer diameter of the electric wire group decreases, and a gap is generated between the electric wire group and the inner peripheral surface of the grommet. However, in the present invention, since the electric wire group coated with the waterproofing agent is wrapped by the elastic foam material sheet, this foam material sheet is interposed between the electric wire group and the grommet, and the waterproofing agent flows. Accordingly, even if a gap is generated, the gap is filled with the foamed material sheet having elasticity, whereby the gap can be reliably prevented from being generated inside the gap grommet.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a waterproof jig 11 is installed on a wiring table 10 for assembling a wire harness. The waterproof jig 11 is supported on a wiring shaft 10 so as to be detachable. 12, a substrate 13 fixed to the upper end of the support shaft 12,
A pair of wire holding members 14 and 15 projecting from the substrate 13 at a required interval are provided.

The pair of wire holding members 14 and 15 are
3, and the electric wire w is fixed to the upper end opening 14b, 1
5b, and has narrow holes 14a, 15a for inserting the electric wires w in parallel in a line. Both surfaces 14c, 15c of the upper end openings of these electric holes for inserting the electric wires have their tips inclined in the opening direction. ing.

As shown in FIG. 2, first, when assembling the wire harness, the wiring board 1 is used by using the waterproof jig 11 described above.
On the wire 0, the electric wire w is wired while holding the electric wire with another electric wire receiving jig 20. A wiring jig 11 is disposed at a portion where the grommet is to be attached, and a pair of wire holding members 14 and 1 are provided.
5 and the wire group W is inserted. At the time of insertion, in the wire insertion slots 14a, 15a of the wire holding members 14 and 15, both ends of the upper end openings 14b, 15b are inclined and open. When the electric wire group W is pushed in, the electric wires w are pushed into the elongated holes 14a and 15a in a state of being aligned one by one. That is, FIG.
As shown in (1), in the waterproof section X, the wires are laid in a state of being arranged adjacent to one row in the vertical direction.

After completing the wiring of the wire group W on the wiring board 10, the waterproofing agent 25 is applied to the wire group W in the waterproof section X by using the applicator 26 filled with the waterproofing agent 25. Is applied. The applicator 26 has a flat spatula 27a at the tip of a tube 27, and nozzles 27b at the required pitch at the tip of the spatula 27a. Therefore, when the tube 27 is pushed, the water stopping agent 25 is pushed out from the nozzle 27b through the spatula 27a.

The water-stopping agent 25 has a viscosity of 1,000 to 2,000.
Poise, a silicone-based water stopping agent, a modified ester resin, a synthetic rubber-based water stopping agent, etc. are used. The above applicator 2
6 is provided with three nozzles 27b at the required pitch,
As shown in FIG. 2 (B), once applied from the upper end to the lower end of the waterproof section X, the applied waterproofing agent spreads to some extent in the horizontal direction.
5 is applied.

Next, as shown in FIG. 2C, the support bar 12 of the waterproof jig 11 is lowered from the wiring stand 10. When the board 13 hits on the wiring board 10, it stops. As the substrate 13 descends, the wire holding members 14 and 15 also descend, and the water stopping agent 3
The wire group W to which 0 has been applied is removed from the waterproof jig 11.

After the jig 11 is detached from the waterproofing jig 11 as described above, a thin foam sheet 23 having elasticity is put on the surface of the wire group W to which the waterproofing agent 25 of the waterproofing section X is applied. In the present embodiment, the foamed material sheet 23 is a foamed sheet made of neoprene rubber and shown in FIG. A release paper 29 is attached to one side of the foam material sheet 23, and the release paper 29 is peeled off and covered with the electric wire group W. It should be noted that a foamed material made of polyurethane may be used, and any foamed material having elasticity and having an independently foamed shape that fills minute gaps is preferably used.

By covering the foam material sheet 23 as described above, the waterproofing agent 25 can be prevented from sticking to the hands of the worker. After covering the foam material sheet 23, as shown in FIG. 2D, the electric wire w is rounded in the foam material sheet 23 to have a circular cross section.

Next, as shown in FIG. 2 (E), the grommet 30 is passed through the waterproof section X, and the grommet 30 is attached to the wire group W.

The work of mounting the grommet 30 is performed before the water-stopping agent 25 is not completely cured due to the efficiency of the work. When inserting the grommet 30, the grommet 3
The diameter-reduced portion 30a is pushed and spread by a spreader (not shown) to insert the wire group. When the spreader is pulled out after insertion, the contraction force of the grommet 30 applies a load to the wire group W of the diameter-reduced portion 30a. Will be done. Therefore, the water-stopping agent 25 that has not yet been cured flows along the longitudinal direction of the electric wire as shown in FIG.

When the water-stopping agent 25 flows as described above, the outer diameter of the wire group W is reduced. However, since the outer periphery of the wire group W is wrapped with the elastic foam sheet 23, the foam sheet 4 expands to fill the gap generated, and FIG.
No gap is generated as shown in FIG.

When the wire group W filled with the water blocking agent 25 is covered with a mere resin film, wrinkles are generated in the film when the grommet is externally fitted, and a gap is generated. When covered with the foam material sheet 23 and compressed by the contraction force of the grommet 30, the gap is not generated as described above because the foam material sheet 23 is restored and filled.

[0028]

As is apparent from the above description, in the waterproof structure of the wire harness according to the present invention, the outer periphery of the wire group filled with the water blocking agent is covered with the elastic foam sheet in a compressed state. Therefore, when the water-stopping agent flows, the foam material sheet is restored, and the gap generated by the water-stopping agent flowing out is filled, so that no gap is generated and the waterproof performance can be improved.

In addition, since the foamed material sheet is in the form of closed foam, it is impermeable to water and air, so that the waterproof performance can be further improved.

According to the method for forming a waterproof structure of a grommet of the present invention, a waterproofing agent is applied to a wire group in a portion where it is necessary to attach a grommet and perform waterproofing when wiring a wire on a wire harness assembly line. Can be applied. That is, the waterproofing agent application step which had to be conventionally performed in a separate step can be performed on the wire harness assembly line, and the waterproofing step can be simplified and speeded up.

Further, since the water-stopping agent is applied to the group of electric wires arranged in a row while being pushed out from a tube or the like, the water-stopping agent is not wasted, and the amount of the water-stopping agent can be reduced to half of the conventional amount. In fact, 10 g-3 g in one conventional grommet
According to the method of the present invention, 0 g of the water-stopping agent has been filled, but only about 5 g to 10 g is sufficient. As described above, since the amount of the used waterproofing agent can be reduced by half, the cost can be reduced.

Furthermore, the method of the present invention can be easily performed using a waterproof jig having a simple structure provided with a pair of wire holding members. Therefore, the equipment can be easily provided, and has an advantage that it can be easily implemented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIGS. 2A to 2E are views showing a process of forming a waterproof structure.

FIG. 3 shows a foam sheet used in the embodiment;
(A) is a perspective view, (B) is an enlarged sectional view.

FIG. 4A is a cross-sectional view showing the operation of the foam material sheet, and FIG. 4B is a cross-sectional view taken along line BB of FIG.

FIG. 5 is a sectional view showing a waterproof structure of a conventional grommet.

FIG. 6 is a schematic view showing a conventional grommet waterproofing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grommet 10 Wiring board 11 Waterproof jig 12 Support rod 13 Substrate 14, 15 Electric wire holding material 14a, 15a Long hole for electric wire insertion 23 Foam material sheet 25 Waterproof agent 26 Coating tool w Electric wire W Electric wire group 30 Grommet W / H wire harness

Claims (2)

[Claims] 1. A waterproof structure for a grommet to be inserted into a panel through hole with a wire harness inserted, wherein a waterproofing agent is filled between electric wires inserted into the grommet, and The wire harness is characterized in that the outer periphery of the wire group filled with the waterproofing agent is wrapped with a sheet made of a foam material having a closed cell shape having elasticity, and the sheet of the foam material is adhered to the inner wall of the grommet. Grommet waterproof structure. 2. A method for forming a waterproof structure of a grommet mounted in a panel through hole with a wire harness inserted therein, wherein the waterproofing between lines is performed when a wire group is laid in assembling the harness. The electric wire groups of the parts are arranged adjacently and arranged in a row, and a waterproof agent having a required viscosity is applied to the parallel electric wire groups so as to penetrate between the electric wires, and then the waterproof agent is applied. A method of forming a waterproof structure through a wire harness, characterized in that an elastic foam sheet having elasticity is placed over the cut portion, the cross section is rounded, and the grommet is passed through the grommet.