JP2009291021A - Waterproof structure of grommet with wire harness inserted thereinto - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the manufacturing workability and the waterproofness of a grommet so configured as to prevent intrusion of water into a wire harness which is routed through a through-hole of a vehicle body panel for separating a water-sprayed region of a vehicle and the interior of the vehicle and is inserted into the grommet. <P>SOLUTION: The wire harness 30 is composed of a group of cables 31. A portion of each cable 32 of the group of cables 31 which is passed through the grommet 10 is spirally wound with a first water absorption tape 20A or round cord composed of woven cloth or unwoven cloth 21 impregnated with resin powder 22 having a water absorption expansibility. During water spraying, a space S1 between the individual cables 32 and a space S2 between each cable 32 and the internal peripheral surface of the grommet 10 are eliminated by expansion of the resin powder 22 having a water absorption expansibility. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a grommet waterproof structure through which a wire harness attached to a through hole of a vehicle body panel is inserted.

  When wiring a wire harness through a panel that partitions an engine room and a vehicle compartment in a vehicle wiring harness, a rubber or elastomer grommet 1 is attached to a through hole 2a formed in the panel 2 as shown in FIG. The wire harness 3 is routed through the grommet 1 to prevent water from entering the passenger compartment, and to protect the wire harness from dust, sound and sound.

This type of grommet 1 is provided with a panel locking portion 1b on the outer peripheral surface of the enlarged diameter portion 1a having a substantially conical cylindrical shape, and the panel locking portion 1b is locked to the inner periphery of the panel through hole 2a. And the panel through hole 2a are securely sealed for waterproofing, while the wire harness 3 is brought into close contact with the reduced diameter pipe portion 1c extending from the reduced diameter side of the enlarged diameter portion 1a of the grommet 1. Yes.
In order to improve the waterproof performance in the through region of the grommet, measures for sealing a gap between the electric wires 3a of the wire harness 3 through which the grommet 1 is inserted and between the electric wires 3a and the pipe portion 1c of the grommet 1 are conventionally used. Various are provided.

For example, it is known that a fluid sealing material is filled into the reduced diameter pipe portion 1c from the enlarged diameter portion 1a of the grommet 1 and penetrates into each gap of the electric wire 3a.
However, if the fluid sealing material is not low in viscosity, it will not easily penetrate into the gaps between the wires. Conversely, if it is low in viscosity, it will easily flow out from the openings at both ends of the through holes of the grommet. It is difficult to fill the material without generating voids. Moreover, the fluid sealing material also has a problem in that it takes time to cure.

Moreover, in Japanese Utility Model Laid-Open No. 63-37027, as shown in FIG. 7A, a portion in which a portion that is inserted into the reduced diameter pipe portion 1c of the grommet 1 of the wire harness 5 is filled with the swelling agent 6 is proposed. Yes. This swelling agent 6 changes into a gel state by water absorption, and fills the gaps between the electric wires to prevent water from entering the wire harness 5.
Specifically, in order to apply the swelling agent 6 to the wire harness 5, as shown in FIG. 7 (B), the wires 5a of the wire harness 5 are unwound on the adhesive sheet 7, and the swelling agent 6 is applied to the wires 5a. After sprinkling evenly, the adhesive sheet 7 converges, but it is not easy to uniformly sprinkle the swelling agent 6 on each electric wire 5a, workability is poor, and water is absorbed when the adhesive sheet 7 converges. There is also a possibility that the expanded resin agent is unevenly distributed. For this reason, voids are generated in the portion where the water-absorbing swelling resin agent is not sprayed, and when the voids are continuous, water is generated through the gaps between the electric wires in the grommet.

Japanese Utility Model Publication No. 63-37027

  The present invention has been made in view of the above problems, and eliminates the need to wait for the sealing material to be cured when a sealing material is used as a water-stopping agent, thereby improving work efficiency and reliably generating gaps between wires. An object of the present invention is to provide a grommet waterproof structure through which a wire harness having a high water-stopping performance is inserted.

In order to solve the above-mentioned problem, the present invention externally attaches a grommet made of rubber or elastomer to a wire harness routed through a through hole of a vehicle body panel that partitions a wet area of a vehicle and a vehicle interior,
A band tape or a round string made of a woven fabric or a non-woven fabric impregnated with a water-absorbing expandable resin powder is spirally wound around the grommet penetration region of each wire of the wire group constituting the wire harness, There is provided a grommet waterproof structure through which a wire harness is inserted, characterized in that a gap between the electric wires and a gap between the electric wires and the grommet inner peripheral surface are sometimes eliminated by expansion of the water-absorbing expandable resin powder.

In this waterproof structure, a strip tape or a round string (hereinafter abbreviated as “water absorption tape or water absorption string”) made of a woven fabric or a nonwoven fabric impregnated with a water-absorbing expandable resin powder is provided for each electric wire, that is, one by one. Since it is spirally wound, the water absorbing tape or the water absorbing string is surely positioned in the gap between the electric wires and the gap between the electric wire and the inner peripheral surface of the grommet, and the water absorbing tape or the water absorbing tape is at least partially in the longitudinal direction. It can be divided by a string. Therefore, the water-absorbing tape or the water-absorbing string expands when it is wet at the dividing position, so that a gap continuous in the electric wire insertion direction can be reliably closed and the flooded path can be blocked.
In Patent Document 1, since the water-absorbing swellable resin powder is only sprinkled on the surface of the electric wire, it is impossible to reliably prevent the occurrence of continuous gaps. Since the water absorbing tape or the water absorbing string impregnated with the swellable resin powder is wound around each electric wire, it is possible to prevent the occurrence of continuous gaps as described above.
Moreover, since the operation | work which winds a water absorption tape or a water absorption string helically for every electric wire is easy to automate, it also becomes possible to improve workability | operativity further by this automation.
Furthermore, unlike the case of filling a sealing material made of a fluid resin, there is no need to wait for the resin to be cured, and there is no need to adjust the viscosity of the resin or to check the degree of spread of the resin. Therefore, it is excellent in manufacturing workability, and quality stability can be improved in terms of water stopping.

  The water absorbing tape or the water absorbing string may be wound while being wrapped around the electric wire, but the wire diameter increases, and even if the wire is roughly wrapped without being wrapped, the gap between the electric wires, The gap between the grommet and the grommet inner peripheral surface can be closed, so that it is not always necessary to wrap the grommet while wrapping.

  The water-swellable resin powder is preferably one whose volume expands to about 100 to 1000 times due to expansion during water absorption. Specifically, those having a chemical composition such as acrylic acid / vinyl alcohol copolymer and sodium acrylate polymer are suitable, and examples thereof include Aqua Sock (trade name: manufactured by Nippon Shokubai Co., Ltd.).

In the grommet penetrating region of the wire group constituting the wire harness, it is preferable that the water-absorbing tape is further spirally wound around the outer periphery of the converged wire group.
Thereby, it can prevent more reliably that inundation generate | occur | produces along the clearance gap between an electric wire outer peripheral surface and a grommet inner peripheral surface.

The grommet has a small-diameter cylindrical portion that is in close contact with the electric wire group, and an enlarged-diameter cylindrical portion that is enlarged from one end of the small-diameter cylindrical portion and has a vehicle body locking groove on an outer peripheral surface thereof. Is preferably wound around a region inserted through the small-diameter cylindrical portion.
In this case, the water-absorbing tape or the water-absorbing string is preferably wound over the entire length of the region inserted into the small-diameter cylindrical portion and both the front and rear sides thereof, specifically, it is preferably wound over a length of 10 cm to 30 cm.

The waterproof structure of the grommet of the present invention is formed by the following method.
In the grommet penetrating region of the electric wire group constituting the wire harness, the water absorbing tape or the water absorbing string is wound around each electric wire in advance in a spiral shape, these electric wires are bundled and converged, and the water absorbing tape is arranged on the outer periphery of the electric wire group. Is wound in advance in a spiral shape, and the wound portion is positioned in the small-diameter cylindrical portion when the wire harness is inserted into the grommet.

As described above, according to the present invention, the water-absorbing tape or water-absorbing string impregnated with a water-absorbing expandable resin powder in a woven or non-woven fabric is spirally wound around each electric wire. A gap between the electric wire and the grommet inner peripheral surface can be divided in the length direction by a water absorbing tape or a water absorbing string. Therefore, when the water-swellable resin powder impregnated in the water-absorbing tape or the water-absorbing string expands at the time of being wet, the gap that continues in the wire insertion direction can be reliably closed, and the wire harness passes through the gap. It is possible to prevent water from entering into the passenger compartment, and to prevent problems such as corrosion and short-circuiting through water in the connectors connected to the wire terminals. In this way, since the occurrence of the flooding path is prevented in principle, there is no need to check the state of filling of the sealing material required when the sealing material is used, and there is no need to wait for the sealing material to harden. , Can increase the work efficiency.
Furthermore, the work of winding the water absorbing tape or the water absorbing string around each electric wire is easy to automate, and this automation can further improve the workability.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show a waterproof structure of the grommet 10 according to the first embodiment of the present invention.
As shown in FIG. 1, the grommet 10 is wired through a through-hole 41 provided in a vehicle body panel 40 (dash panel) that partitions the engine room X and the vehicle compartment Y, which is a wet area of the automobile. And attached to the through hole 41 in a state where the wire harness 30 is inserted.

  The grommet 10 is an integrally molded product made of rubber. As shown in FIG. 2C, the grommet 10 is in close contact with the wire group 31 constituting the wire harness 30 and is expanded from one end of the small diameter cylinder portion 11. A diameter-expanding cylindrical portion 12 is provided along the axial direction, and wire through-holes 13 and 14 are provided at both ends in the axial direction. A vehicle body locking groove 15 is formed in an annular shape on the outer peripheral surface of the distal end side of the enlarged diameter cylindrical portion 12.

  1 to 4, 20A and 20B are water-absorbing tapes, and the water-absorbing tapes 20A and 20B are long strips impregnated with a water-absorbing expandable resin powder 22 having a chemical composition of acrylic acid / vinyl alcohol copolymer. The non-woven fabric 21. 20A is a first water-absorbing tape, 20B is a second water-absorbing tape, and the second water-absorbing tape 20B is wider than the first water-absorbing tape 20A.

As shown in FIG. 2A, the first water absorbing tape 20 </ b> A is spirally wound around the outer circumference of each electric wire 32 of the electric wire group 31 constituting the wire harness 30 inserted through the grommet 10. The winding position is a length region including a region A (hereinafter abbreviated as “small-diameter cylindrical portion penetration region A”) inserted into the small-diameter cylindrical portion 11 of the grommet 10 and both front and rear regions of the small-diameter cylindrical portion penetration region A. It is said.
The first water absorbing tape 20 </ b> A is spirally wound around the outer circumference of each electric wire 32 in a rough winding shape. Since the first water-absorbing tape 20A is impregnated with the adhesive resin solution together with the water-absorbing expandable resin 22, the first water-absorbing tape 20A is fixed to each electric wire 32 in a wound state.

As shown in FIG. 2 (B), a portion B (hereinafter abbreviated as “winding portion B”) around which the first water-absorbing tape 20A is wound around each electric wire 32 is aligned and converged. The second water-absorbing tape 20B is wrapped around the outer periphery of the same area as the winding part B and wound.
When the respective electric wires 32 are converged and wound around the second water absorbing tape 20B, the first water absorbing tapes 20A of the adjacent electric wires 31 are converged so as not to overlap each other as shown in FIG. It winds with the water absorption tape 20B.
Since the second water-absorbing tape 20B is also impregnated with the adhesive resin solution, the second water-absorbing tape 20B is fixed to the outer periphery of the wire group 31 in a wound state.
Further, as shown in FIG. 2D, pressing adhesive tapes 23 are wound around both ends of the winding portion B.
Therefore, even if the first and second water-absorbing tapes 20A and 20B do not provide the adhesiveness that is fixed to the electric wires 32 and the electric wire group 31 when they are wound, or the adhesive performance is low, the first and second water-absorbing tapes 20A and 20B The winding state is maintained.

As described above, the first water-absorbing tape 20A is wound around the outer periphery of each electric wire 32, and the second water-absorbing tape 20B is wound around the outer periphery of the electric wire group 31 in which the electric wires 32 are converged, as shown in FIG. Further, the wire group 31 is inserted into the grommet 10 so that the central portion of the winding portion B is positioned in the small diameter cylindrical portion 11 and both ends of the winding portion B are exposed from both ends 11a and 11b of the small diameter cylindrical portion 11. ing.
That is, one end side is pulled out from the opening side end 11 a of the small diameter cylindrical portion 11, and the other end side is projected to the diameter expanding cylindrical portion 12 side of the grommet 10.

  The wire group 31 is fixed to the grommet 10 by winding the winding portion B drawn from the opening-side end 11 a of the small-diameter cylindrical portion 11 from the outer peripheral surface of the small-diameter cylindrical portion 11 with the adhesive tape 24.

  The waterproof structure of the grommet described above is formed by the steps shown in FIGS. 2A to 2D, and the first and second water-absorbing tapes 20A and 20B are formed in the small diameter cylindrical portion 11 of the grommet 10 as shown in FIG. Is arranged.

In the grommet having the waterproof structure, as shown in FIG. 3, the first water-absorbing tape 20A wound around each electric wire 32 divides the gap S1 between the adjacent electric wires 32 at a plurality of locations. Further, the second water absorbing tape 20 </ b> B wound around the outer periphery of the electric wire group 31 is interposed in the gap S <b> 2 between the electric wire 32 at the outer peripheral position and the inner peripheral surface of the small diameter cylindrical portion 11.
When the water-absorbing expandable resin powder 22 impregnated in the first and second water-absorbing tapes 20A and 20B comes into contact with water when it is wet, the gap S1 between the adjacent electric wires 32 and the electric wires 32 are expanded as shown in FIG. And the gap S2 with the inner peripheral surface of the small-diameter cylindrical portion 11 can be completely blocked, and water can be prevented from entering the wire harness 30 and further into the passenger compartment Y side through the gaps S1 and S2. .

Therefore, the work for confirming the filling state of the sealing material and the process of waiting for the sealing material to be hardened, which are necessary when the molten sealing material is poured into the grommet as in the prior art, become unnecessary.
Moreover, the waterproof structure which has a reliable water stop function can be formed by the simple operation | work which winds the 1st, 2nd water absorption tape 20A, 20B around an electric wire, and workability | operativity and quality stability can be improved.

In addition, this invention is not limited to the said embodiment.
As shown in FIG. 5, a water-absorbing round string 25 formed by impregnating a cotton string with water-absorbing expandable resin powder 22 is spirally wound around the outer periphery of each electric wire 32 as shown in FIG. Also good.
Further, when the first water absorbing tape 20A is wound around each electric wire 32, the first water absorbing member wound around the electric wire 32 at the outer peripheral position of the electric wire group 31 in contact with the inner peripheral surface of the small-diameter cylindrical portion of the grommet in the state of the electric wire group 31. The tape 20A can contact the inner peripheral surface of the small-diameter cylindrical portion of the grommet, and the water immersion path that propagates to the inner peripheral surface can be blocked. Therefore, waterproof performance can be ensured without winding the second water-absorbing tape 20 </ b> B around the outer peripheral surface of the wire group 31.

It is explanatory sectional drawing which shows the state which attached the grommet which concerns on 1st embodiment of this invention to the through-hole of the vehicle body. (A)-(D) are explanatory drawings which show the formation method of the waterproof structure of the grommet shown in FIG. It is sectional drawing which shows the principal part structure inside the grommet shown in FIG. It is sectional drawing which shows the state inside a grommet at the time of flooding. It is explanatory perspective view which shows the example which replaced with the 1st water absorption tape and used the water absorption round string. It is a figure which shows a prior art example. (A) (B) is a figure showing other conventional examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Grommet 11 Small diameter cylinder part 20A 1st water absorption tape 20B 2nd water absorption tape 22 Water absorption expandable resin powder 30 Wire harness 31 Electric wire group 32 Each electric wire A Small diameter cylindrical part penetration area B Winding part

Claims (3)

A grommet made of rubber or elastomer is externally mounted on a wire harness that is routed through a through hole in a vehicle body panel that divides the wet area of the vehicle from the vehicle interior.
A band tape or a round string made of a woven fabric or a non-woven fabric impregnated with a water-absorbing expandable resin powder is spirally wound around the grommet penetration region of each wire of the wire group constituting the wire harness, A grommet waterproof structure through which a wire harness is inserted, characterized in that the gap between the wires and the gap between the wires and the grommet inner peripheral surface are sometimes eliminated by the expansion of the water-swellable resin powder.   A band tape made of a woven fabric or a nonwoven fabric impregnated with the water-swellable resin powder is spirally wound around the grommet penetrating region of the electric wire group constituting the wire harness around the outer circumference of the converged electric wire group. A waterproof structure for a grommet through which the wire harness according to claim 1 is inserted.   The grommet has a small-diameter cylindrical portion that is in close contact with the electric wire group, and an enlarged-diameter cylindrical portion that is enlarged from one end of the small-diameter cylindrical portion and has a body locking groove on an outer peripheral surface. The waterproof structure of the grommet which penetrated the wire harness of Claim 1 or Claim 2 wound around the area | region penetrated in the said small diameter cylinder part.

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