JPH0721862A - Waterproof structure of grommet - Google Patents

Abstract

PURPOSE:To provide a waterproof structure for grommet which surely prevents the penetration of moisture when a wire harness is curved, and has excellent working property. CONSTITUTION:A grommet 11 has a radially extended hole 11d provided on a panel installing part 11b to be mounted on a through hole 7a provided on a wall part 7; and a radially contracted hole 11e provided on a wire harness insert part 11c protruded from the panel installing part, and a wire harness 2 is inserted through the radially extended hole and the radially contracted hole. A first filler layer 15 consisting of a liquefied hardening filler having a short hardening time is provided on the radially contracted hole side of the radially extended hole. A second filler layer 16 consisting of a liquefied hardening filler having high permeability is laminated on the first filler layer. A third filler layer consisting of a liquefied hardening filler having a short hardening time is laminated on the second filler layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grommet waterproof structure, and more specifically, it is fitted onto a wire harness inserted through a through hole provided in a wall portion of a vehicle body panel of an automobile to hold the wire harness in the through hole. The present invention relates to a grommet waterproof structure.

[0002]

2. Description of the Related Art Conventionally, in order to prevent water from entering through a gap between a grommet and a wire harness and a gap between electric wires constituting the wire harness, it is in a liquid state at the time of injection, but with the passage of time. A waterproof structure has been proposed in which a grommet is filled with a hardening filler (liquid hardening filler).

The liquid curable filler easily penetrates into the gap between the grommet and the wire harness and between the electric wires forming the wire harness in order to surely prevent the entry of water (permeability), and It is required to cure as early as possible after injection (early curability) so that the process can be immediately moved to the next step, but the penetrability and the early curability are contradictory requirements. That is, generally, a liquid curable filler having a low viscosity and excellent permeability has a long curing time, while a liquid curable filler having a short curing time has a high viscosity and a poor permeability.

On the other hand, Japanese Utility Model Laid-Open No. 4-48098 proposes a waterproof structure as shown in FIG.
In this waterproof structure, the grommet 1 has the panel mounting portion 1a.
It has an insertion hole 1e consisting of an enlarged diameter hole 1b provided in the wire harness and a reduced diameter hole 1d provided in the wire harness insertion portion 1c. After inserting the wire harness 2 into the insertion hole 1e, liquid penetrability with high permeability is provided. A filler 3 made of a filler is injected into the grommet 1, and then a filler 4 made of a liquid curable filler having a short curing time is injected into the grommet 1 to form a two-layer structure.

In this waterproof structure, the highly penetrable filler 3 is permeated into the gap between the wire harness 2 and the grommet 1 and the gap between the electric wires 6 forming the wire harness 2 to improve the waterproof property. , This filler 3
By disposing the filler 4 having a shorter curing time on the surface side than that, it is not necessary to wait for the filler 3 having a long curing time to be completely cured, and the workability is improved.

[0006]

However, the waterproof structure shown in FIG. 7 has the following disadvantages. That is, as shown in FIG. 8, the grommet 1 is attached to a wall portion 7 such as a vehicle body panel.
After being mounted in the through hole 7a provided in the wire harness 2
In many cases, the wire harness insertion portion 1c of the grommet 1 is also bent. However, since the highly permeable filler 3 is hardened in a state where it has penetrated to the portion of the wire harness 2 located in the wire harness insertion portion 1c, when the wire harness insertion portion 1c is bent, The position of the filling material 3 may be displaced and the gap 8 may be generated. Further, the bending of the wire harness insertion portion 1c may cause a crack 9 in the filler 3.

When the gap 8 is present, moisture enters the gap 8 between the wire harness 2 and the adhesive tape 10 wound around the wire harness insertion portion 1c by a capillary phenomenon. Further, when the crack 9 is generated, as shown by a dotted line in the figure, moisture penetrates from the outside A to the inside B of the wall portion 7 through the gap between the electric wires 6 forming the wire harness 2. Therefore, with the waterproof structure shown in FIG. 7, it is difficult to ensure waterproofness when the wire harness 3 is bent.

The present invention has been made to solve the problems in the conventional waterproof structure of the grommet as described above, and even when the wire harness is bent after the grommet is mounted in the through hole, the moisture content is reduced. The purpose of the present invention is to provide a waterproof structure of a grommet which can surely prevent the invasion of the above and is excellent in workability.

[0009]

SUMMARY OF THE INVENTION Therefore, according to the present invention, a grommet for inserting a wire harness into an enlarged diameter hole provided in a panel mounting portion and a reduced diameter hole provided in a wire harness insertion portion protruding from the panel mounting portion. The waterproof structure of claim 1, wherein the first filling material layer, the second filling material layer, and the third filling material layer
Filler layers are sequentially laminated and provided, the first filler layer is made of a liquid curable filler having a short curing time, and the second filler layer is made of a liquid penetrating liquid curable filler having high permeability, The third filler layer is provided with a grommet waterproof structure characterized by being made of a liquid curable filler having a short curing time.

[0010]

In the grommet waterproof structure of the present invention having the above-mentioned structure, the first filler layer made of a liquid curable filler having a quick curing time from the side of the reduced diameter of the expanded hole, the liquid curable filler having high permeability. Since the second filler layer made of a material and the third filler layer made of a liquid curable filler having a short curing time are sequentially laminated and provided, the wire harness of the portion located in the wire harness insertion portion of the grommet is , The filler does not penetrate. Therefore, even if the wire harness insertion portion is bent by changing the direction of the wire harness after attaching the grommet to the wall portion, the positions of the first to third filler layers with respect to the grommet may be displaced or cracks may be generated. Never.

When forming the waterproof structure of the grommet of the present invention, after fixing the grommet to the wire harness, the liquid hardening fillers constituting the first to third fillers are sequentially injected into the insertion holes. However, since the second filler layer made of the liquid curable filler having high permeability is provided between the first filler layer and the third filler layer, which have a short curing time, the diameter-reduced holes and the diameter-expanded holes of the grommet are provided. While the space between them is closed by the first filler layer, the opening of the expanded hole is closed by the third filler layer, and once the third filler layer is formed, the second filler layer having a long curing time is formed. The liquid curable filler does not flow out of the grommet.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in the drawings. In the embodiment of the present invention shown in FIG. 1, a grommet 11 has a panel mounting portion 11b provided with an engaging groove 11a on the outer periphery, which engages with a through hole 7a of a wall portion 7 which is a vehicle body panel of an automobile, and this panel mounting portion. The wire harness insertion portion 11c protruding from the portion 11b is provided.

The panel mounting portion 11b is provided with a large diameter expanding hole 11d. Further, the wire harness insertion portion 11c is provided with a small diameter reducing hole 11e which is continuous with the diameter increasing hole 11d. The diameter increasing hole 11d and the diameter reducing hole 11e are provided.
Forms an insertion hole 11f for inserting the wire harness 2 into the grommet 11.

The wire harness 2 inserted through the insertion hole 11f has an adhesive tape 12 on the outer periphery of the outer side A of the wall portion 7.
Is wrapped in a wrap. The tip 1 of this adhesive tape 12
2a is located slightly closer to the expanded diameter hole 11d side than the connecting portion between the expanded diameter hole 11d and the reduced diameter hole 11e. Further, an adhesive tape 13 is wound around the outer circumference of the wire harness 2 and the outer circumference of the wire harness insertion portion 11c of the grommet 11.
The adhesive tape 13 fixes the grommet 11 to the wire harness 2.

The insertion hole 11f is filled with a filling material having a three-layer structure. First, a first filler layer 15 made of a liquid curable filler having a short curing time is provided on the side of the reduced diameter e of the enlarged diameter hole 11d. It occupies from the connecting portion of the reduced diameter hole 11e to the vicinity of the center of the enlarged diameter hole 11d.

A second filler layer 16 is provided by laminating with the first filler layer 15. The second filler layer 16 is made of a liquid curable filler having high permeability, and is used for the wire harness 2
The liquid curable filler of the second filler layer 16 that has penetrated between the electric wires 6 has penetrated to the reduced diameter hole 11e side beyond the boundary between the first filler layer 15 and the second filler layer 16. . But,
The tip end position 16a on the left side of the second filling material layer 16 in the drawing is inside the enlarged diameter hole 11d of the grommet 11, and the second filling material layer 16
The liquid curable filler is used as the reduced diameter hole 11 of the wire harness 2.
It does not penetrate to the part located in e.

Further, a third filler layer 17 is provided by laminating it on the second filler layer 16. This third filler layer 1
7 is made of a liquid curable filler having a short curing time, is located near the opening 11g of the enlarged diameter hole 11d, and the opening 11g is closed by the third filler layer 17.

As described above, in this embodiment, the liquid curable filler having high permeability is provided between the first filler layer 15 and the third filler layer 17 made of the liquid curable filler having a short curing time. The second filling material layer 16 is formed.

Therefore, in the waterproof structure of this embodiment, as shown in FIG.
As shown in (A), on the wire harness insertion portion 11c side of the expanded diameter hole 11d, the electric wire 6 that constitutes the wire harness 2 is formed.
The liquid curable filler of the second filler layer 16 is filled in between, and the liquid curable resin of the first filler layer 15 is filled between the outer periphery of the wire harness 2 and the grommet 11.

On the other hand, as shown in FIG. 2 (B), the portion of the wire harness 2 located in the reduced diameter hole 11e is filled with the liquid curable filler of either the first filler layer 15 or the second filler layer 16. The material does not penetrate, and the adhesive tape 12 wrapped around the outer circumference of the wire harness 2 is in close contact with the reduced diameter hole 11c.
Therefore, even when the wire harness insertion portion 11c is bent to change the direction of the wire harness 3 with the grommet 11 mounted in the through hole 7a, the second filler made of the liquid penetrable filler having high permeability described above. The position of the layer 16 with respect to the grommet 11 does not shift and the second filler layer 11 does not crack. Therefore, in the waterproof structure of this embodiment,
Even when the wire harness 2 is bent after the grommet 11 is attached to the through hole 7a, it is possible to reliably prevent the intrusion of water.

Next, a method of molding the waterproof structure of this embodiment having the above-mentioned structure will be described. First, as shown in FIG. 3, the adhesive tape 12 is wrapped in advance at a predetermined position of the wire harness 2 to bind the electric wires 6, and then the wire harness 2 is inserted into the insertion hole 11 f of the grommet 11. At this time, the tip 12a of the adhesive tape 12 wrapped by the wrapping
Are positioned slightly closer to the diameter-expanded hole 11d side than the connecting portion between the diameter-expanded hole 11d and the diameter-reduced hole 11e. After positioning the wire harness 2 in this way, the wire harness insertion portion 11
The adhesive tape 13 is wound around c and the outer circumference of the wire harness 2 to fix the grommet 11 to the wire harness 2.

Next, as shown in FIG. 4, a liquid curable filler for forming the first filler layer 15 is injected into the insertion hole 11f of the grommet 2 fixed to the wire harness 2. The liquid curable filler forming the first filler layer 15 is a filler having a short curing time as described above, and has high viscosity and low permeability. Therefore, the liquid curable filler of the first layer 15 does not penetrate to the portion of the wire harness 2 located in the reduced diameter hole 11e.

After the liquid curable filler of the first filler layer 15 is hardened, as shown in FIG. 5, a liquid curable filler for forming the second filler layer 16 in the insertion hole 11f is applied. inject. Since this liquid curable filler has high permeability as described above, the outer periphery of the wire harness 2 and the grommet 11 are
While penetrating into the gap between the two, the gap between the electric wires 6 forming the wire harness 2 permeates toward the reduced diameter hole 11e side. However, as described above, the first filler layer 1 made of a liquid curable filler having a short curing time is already provided in the enlarged diameter hole 11d.
5, the liquid curable filling material of the second filling material layer 16 does not penetrate to the portion of the wire harness 2 located in the reduced diameter hole 11e.

Next, as shown in FIG. 6, a liquid curable filler for forming the third filler layer 17 is filled from above the second filler layer 16. Since this liquid curable filler has a short curing time as described above, the opening 11g of the enlarged diameter hole 11d is quickly closed by the third filler layer 17.

In the state in which the third filler layer 17 is formed, the space between the reduced diameter hole 11e and the enlarged diameter hole 11d of the grommet 11 is closed by the first filler layer 15 while the expanded diameter hole 11 is formed.
Since the opening 11g of d is closed by the third filling material layer 17, the liquid curable filling material of the second filling material layer 16 does not completely cure, but the diameter reducing hole 11e and the diameter expanding It does not flow out through the opening 11g of the hole 11d. Therefore,
In the present embodiment, once the third filler layer 17 is formed, the panel of the grommet 11 regardless of whether the liquid curable filler of the second filler layer 16 is hardened or uncured. The work of attaching the mounting portion 11b to the through hole 7a, carrying the grommet 11 and the wire harness 2, and the like can be performed, and the workability is significantly improved.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in the above-described embodiment, the second filler layer 16 is a liquid curable filler having high permeability, but the second filler layer 16 is a gel that does not completely cure but gels even after a lapse of time. It may be used as a material.

As is clear from the above description, in the waterproof structure of the grommet according to the present invention, the first filler layer made of a liquid curable filler having a quick curing time is provided on the side of the reduced diameter of the enlarged diameter of the grommet. Since the second filler layer made of a liquid curable filler having high permeability and the third filler layer made of a liquid curable filler having a short curing time are sequentially provided, the second filler layer is located in the wire harness insertion portion of the grommet. Since the filler does not permeate the part of the wire harness, even if the direction of the wire harness is changed and the wire harness insertion part is bent after the grommet is attached to the wall part, the first to third parts are bent.
It is possible to obtain high waterproofness without shifting the position of the filler layer with respect to the grommet or causing cracks.

Further, in the present invention, as described above, the liquid curable filler having high permeability is provided between the first filler layer and the third filler layer, which are made of the liquid curable filler having a short curing time. Since the second filler layer is formed, the first filler layer closes the gap between the reduced diameter hole and the enlarged hole of the grommet, while the opening of the enlarged hole is closed by the third filler layer. Second above
The liquid curable filler in the filler layer does not flow out of the grommet even in a state where it is not completely cured. Therefore, in the present invention, once the third filler layer is formed, it is possible to move to the next step without waiting for the second filler layer to harden, and the workability is significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing a waterproof structure for a grommet according to an embodiment of the present invention.

2A is a sectional view taken along line CC of FIG. 1, and FIG. 2B is a sectional view taken along line DD of FIG.

FIG. 3 is a schematic diagram for explaining a method for manufacturing the waterproof structure for the grommet according to the embodiment.

FIG. 4 is a schematic diagram for explaining a method for manufacturing the grommet waterproof structure according to the embodiment.

FIG. 5 is a schematic diagram for explaining a method for manufacturing the waterproof structure for the grommet according to the embodiment.

FIG. 6 is a schematic diagram for explaining a method of manufacturing the waterproof structure for the grommet according to the embodiment.

FIG. 7 is a schematic view showing an example of a conventional grommet waterproof structure.

FIG. 8 is a schematic view for explaining a problem in a conventional grommet waterproof structure.

[Explanation of symbols]

 2 wire harness 6 electric wire 7 wall part 7a through hole 11 grommet 11b panel mounting part 11c wire harness insertion part 11d expanded diameter hole 11e reduced diameter hole 11f insertion hole 11g opening 12,13 adhesive tape 15 first filling material layer 16 second filling Material layer 17 Third filler layer

Claims (1)

[Claims] 1. A waterproof structure of a grommet for inserting a wire harness into an enlarged diameter hole provided in a panel mounting portion and a reduced diameter hole provided in a wire harness insertion portion projecting from the panel mounting portion, wherein The first filler layer, the second filler layer, and the third filler layer are sequentially stacked from the reduced diameter side of the hole, and the first filler layer is made of a liquid curable filler having a short curing time. The waterproof structure of grommet, wherein the second filler layer is made of a liquid curable filler having high permeability, and the third filler layer is made of a liquid curable filler having a short curing time.