JP3022064B2 - Wire harness integrated grommet and molding method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire harness-integrated grommet and a method of forming the same.

[0002]

2. Description of the Related Art Conventionally, a grommet as shown in FIG. 11 has been proposed in Japanese Utility Model Laid-Open No. 01-111417 as an example of a grommet integrally formed by insert-molding this kind of wire harness.

In the grommet 1, a wire harness 4 in which an adhesive tape 3 is wound around a bundle of electric wires 2 is arranged in a pair of dies 6A and 6B provided with cavities 5 for forming grommets. By filling the inside with a resin material, it is integrally formed with the wire harness 4.

[0004]

However, the above conventional structure has the following drawbacks. First
Normally, a wire harness 4 indicated by 4a in FIG.
Adhesive tape 3 is also wound around the portion arranged in the cavity 5 of this example. As the adhesive tape 3, an adhesive tape made of PVC (polyvinyl chloride) is generally used, and its heat-resistant temperature is 80 ° C. It is about. Also, the heat-resistant temperature of the insulating coating portion of the electric wire 2 is about 80 ° C.

[0005] On the other hand, among the resin materials currently provided, there is an "elastomer" which is suitable for a grommet which is integrally molded with a wire harness. It is necessary to maintain the mold at about 40 ° C.

Therefore, when the above elastomer is used as the resin material, the adhesive tape 3 and the insulating coating portion of the wire 2 are melted in the portion 4a due to the heat of the melted elastomer, and the wire 2 is maintained in a bundled state. It may not be possible or the conductors of the adjacent electric wires 2 may come into contact with each other.

[0007] Also, the mold 6 shown by 4b and 4c in FIG.
The pressure-sensitive adhesive tape 3 near the outside of A, 6B may be peeled off by the heat of the molten elastomer, and moisture may intrude therefrom to cause an electrical failure.

Second, as shown in FIG. 12A, wire harness insertion grooves 7a and 7b provided on both sides of the cavity 5 of the molds 6A and 6B are provided to prevent the resin from flowing inside the cavity 5. The dimensions are set to be substantially equal to the diameter of the wire harness 4 so that no gap is formed between the wire harness 4. On the other hand, since the wire harness 4 is formed by bundling the plurality of electric wires 2 with the adhesive tape 3, the cross section cannot be a perfect perfect circle, and there is a portion X whose outer diameter has expanded due to the bending of the electric wire 2. Therefore, when the wire harness 4 is arranged in the dies 6A and 6B and the portion X is arranged in the wire harness insertion groove 7a, there is a possibility that the dies 6A and 6B may cut into the electric wire 2 and break. is there. Further, the wire harness 4 has a portion Y in which the cross section of the wire harness 4 is non-circular such as an ellipse as shown in FIG. If the wire harness 4 is disposed in the wire harness insertion groove 7b, a gap may be formed between the dies 6A and 6B and the wire harness 4, and the resin material may flow out of the cavity 5, and the grommet may not be formed.

Third, the dies 6A and 6B are manufactured with high dimensional accuracy in order to prevent generation of burrs at the time of resin molding, and sharp edges 9 are formed at portions where the cavity 5 and the split surface 8 are connected. Are formed. Therefore, when the wire harness 4 hits the edge 9 when the wire harness 4 is placed on the molds 6A and 6B, the relatively soft adhesive tape 3 and the insulating coating portion of the electric wire 2 are damaged, the conductor is exposed, and the electric power is removed. There is a possibility of causing a mechanical failure.

Fourth, since the wire harness insertion grooves 7a and 7b of the dies 6A and 6B need to be set to dimensions suitable for the diameter of the wire harness 4, the electric wires constituting the wire harness 4 are required. If the diameter of the wire harness 4 is different due to the difference in the number of the wire harnesses 2, the thickness of the adhesive tape 3, etc., it is necessary to prepare a mold in accordance with the diameter, which increases the cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems in the grommet integrally formed with the wire harness. In the grommet integrally formed with the wire harness, an adhesive tape formed by heat of a molten resin is provided. To prevent the melting of the coating of the wire and electric wire and the peeling of the adhesive tape,
Prevention of wire breakage in the wire harness arrangement groove of the mold, prevention of breakage of the wire harness at the edge of the mold, prevention of resin outflow from the cavity, and transfer of one mold to wire harnesses with different outer diameters The purpose of the present invention is to reduce costs by making it sharable when forming the grommet.

[0012]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a wire in which a sheet-like heat-insulating flexible member is wrapped around a resin-molded grommet so that at least a part of the grommet has a multilayer structure, and is wound around the outer peripheral surface. A wire harness-integrated grommet characterized in that the harness is insert-molded.

The heat-insulating flexible member is made of silicon rubber, foamed EPDM, or the like.
At least a part is wrapped and wound in multiple layers, and is wound so as to have a diameter such that the outer peripheral surface is elastically pressed against the wire harness through groove of the mold to be insert-molded. Furthermore, foamed EP is used as a heat insulating flexible member.
When using DM, it is preferable to wrap a heat-resistant tape around the outer periphery.

The grommet forming material is preferably an elastomer, ethylene propylene rubber (EPDM), chloroprene rubber (CR), or the like.

The present invention further provides a wire harness using a pair of dies each having a cavity having a shape corresponding to the shape of the grommet body to be molded, and a wire harness through groove continuous on both sides of the cavity. A method of integrally molding with a grommet by insert molding, wherein a sheet-like heat-insulating flexible member is wrapped around an outer peripheral surface of a required portion of a wire harness so that at least a part thereof has a multilayer structure, and the heat-insulating flexible member is wound. The outer diameter of the flexible member is set to be larger than the diameter of the tube formed by the wire harness insertion groove of the pair of dies, and the wire harness around which the heat insulating flexible member is wound is used as a grommet forming mold. Through the inside of the cavity and elastically press-fit into the wire harness insertion groove continuous with both sides of the cavity. By filling a resin into the mold cavity, providing a method of molding a piece is formed by the forming wire harness-integrated grommet grommet to the outer peripheral surface of the heat insulating flexible member.

[0016]

[0017]

According to the wire harness-integrated grommet of the present invention having the above-described structure, since the heat-insulating flexible member is wound around the wire harness, the heat of the molten resin causes the adhesive tape of the wire harness and the insulating coating material of the electric wire. Does not dissolve or the adhesive tape near the mold does not peel off.

Further, in the present invention, since the heat-insulating flexible member is wound around the wire harness as described above, the wire harness may be damaged at the edge of the mold when the wire harness is arranged in the mold. There is no. Further, since the heat-insulating flexible member is elastically compressed and closely adheres to the wire harness insertion groove of the mold, no gap is generated between the wire harness and the wire harness insertion groove. There is no possibility that the wire harness will cut into the wire and break.

Further, in the present invention, the number of turns of the heat insulating flexible member is set to be small for a wire harness having a large diameter, and the number of turns of the heat insulating flexible member is set to be small for a wire harness having a small diameter. By setting the diameter to be large and keeping the diameter of the portion around which the heat insulating flexible member is wound, one mold can be shared for wire harnesses having different diameters.

[0020]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. As shown in FIGS. 1 and 2,
A sheet-shaped heat-insulating flexible member 11 is wound around and fixed to the wire harness 4, and a resin grommet 12 is integrally formed at a portion where the heat-insulating flexible member 11 is fixed.

As shown in FIG. 3, the heat-insulating flexible member 11 is a sheet-like member made of silicon rubber provided with an adhesive layer 11a on one side, and has a property of blocking heat. It is rich in flexibility and elasticity. In the present embodiment, the pressure-sensitive adhesive layer 11a is made of a rubber-based pressure-sensitive adhesive and has a thickness of 200 to 300 μm. In addition, the adhesive layer 1
1a is not limited to a rubber-based pressure-sensitive adhesive material, and any material having a certain degree of heat resistance and little change in physical properties due to heat may be used.

The heat-insulating flexible member 11 is provided on the adhesive layer 1.
It is wound around the outer periphery of the wire harness 4 from above the adhesive tape 3 so that 1a is inside. Further, adhesive tapes 13 for fixing and waterproofing are wound around both ends of the heat insulating flexible member 11 wound around the outer peripheral portion of the wire harness 4, and the position of the heat insulating flexible member 11 with respect to the wire harness 4 moves. In addition to fixing and holding it so as not to exist, moisture is prevented from entering between the heat insulating flexible member 11 and the adhesive tape 3 of the wire harness 4. Note that, instead of the adhesive tape 13, both ends of the heat-insulating flexible member 11 may be fixed to the wire harness 4 with a tightening band (tie band).

In this embodiment, the thickness t of the heat insulating flexible member 11 is set to 4 mm. The length L of the heat-insulating flexible member 11 is set so that it can be wound once and half around the wire harness 4. Accordingly, the heat-insulating flexible member 11 wound around the wire harness 4 has a single-layer structure 11b that extends around the outer periphery of the wire harness 4 and a lap portion 11c that overlaps the outer periphery of the single-layer structure 11b for substantially half a circumference to form a multilayer structure. Having. Further, as described later, the width W of the heat insulating flexible member 11 is
A, 16B, when placed on both ends of the mold 16A, 1
6B so as to project outside.

The grommet 12 is made of an elastomer and is integrally formed by dies 16A and 16B as described later. The grommet 12 has a fitting groove 12a, and the fitting groove 12a is fitted into a through hole 15a provided in a wall portion 15 of a vehicle body panel or the like of the vehicle, so that the wire harness 4 has a through hole 15a. Is held in a state where it is inserted through.

Next, a method of forming the wire harness integrated grommet according to the present embodiment will be described. First,
As shown in FIG. 4A, the heat-insulating flexible member 11 is wound one and a half times at a predetermined position of the wire harness 4 with the adhesive layer 11a inside. Next, adhesive tapes 13 are wound around both ends of the wound heat-insulating flexible member 11 and fixed to the wire harness 4. In this embodiment, the diameter (harness diameter D1) of the wire harness 4 is 25 mm, and the heat insulating flexible member 11 having the thickness t of 4 mm is wound once and a half times. Of the part around which the conductive member is wound (grommet forming part diameter D2)
Is 37 mm.

Next, as shown in FIG. 5, the wire harness 4 around which the heat-insulating flexible member 11 is wound is disposed in one of the pair of dies 16A and 16B.
Each of the dies 16A and 16B has a cavity 17 having a shape corresponding to the shape of the grommet body 12 to be molded, and wire harness insertion grooves 18a and 18b having a semicircular cross section are provided on both sides of the cavity 17. The dimensions of the wire harness insertion grooves 18a and 18b are
The state where the two molds 16A and 16B are overlapped with each other (FIG. 7)
Shown in ) Is set such that a tube portion having a diameter D3 of 32 mm is formed. The other mold 16A is provided with a resin injection hole 19a continuous from the outside to the cavity 17.

The wire harness 4 includes a heat insulating flexible member 11
Are disposed so that both ends of the molds are located outside the molds 16A and 16B. At this time, even if the worker accidentally causes the heat insulating flexible member 11 to abut on the edge 20 formed at the joint between the cavity 17 and the split surface 19, the wire harness 4
The adhesive tape 3 and the electric wire 2 are not damaged because they are protected by the heat insulating flexible member 11.

Next, as shown in FIGS. 6 and 7, the mold 6B on which the wire harness 4 is arranged and the other mold 6A are overlapped on the split surface 19. At this time, while the diameter D2 of the grommet forming portion is 37 mm, the diameter D3 of the tube portion formed by the wire harness arrangement grooves 18a and 18b.
Is 32 mm, and the diameter of the grommet forming portion is 5 mm larger. Therefore, the heat-insulating flexible member 11 made of silicon rubber having elasticity is elastically compressed by being sandwiched between the wire harness insertion grooves 18a and 18b of both the dies 16A and 16B, and is thereby compressed by the wire harness insertion grooves 18a and 18b. In close contact.

Next, a nozzle (not shown) of a molding machine was connected to the resin injection port, and the molten elastomer (about 19
0 ° C.) into the cavity 17. The mold 16
The temperatures of A and 16B are maintained at 40 ° C.

At this time, since the heat-insulating flexible member 11 is wound around the outer periphery of the wire harness 4 in the cavity 17, the insulating coating of the adhesive tape 3 and the electric wire 2 of the wire harness 4 due to the heat of the molten elastomer is provided. The rise in temperature of the member 2a is significantly reduced.

For example, when a heat insulating holding member 11 made of an elastomer having a thickness of 4 mm is wound once and a half around the outer periphery of the wire harness 4 as in the present embodiment, the above-mentioned molten elastomer is placed in the cavity 7 for about 5 seconds to 10 seconds. And then cooled for about 8 to 16 seconds, the temperature of the wire harness 4 rises only to about 50 ° C. at the maximum.

Therefore, in this embodiment, the tape 3 of the wire harness 4 and the insulating coating 2a of the electric wire 2 are not melted by the heat of the melted elastomer, and the conductor 2 of the electric wire 2 is not melted.
b is not exposed.

As described above, the heat insulating flexible member 11 is elastically compressed and closely attached to the wire harness insertion grooves 18a and 18b of the dies 16A and 16B. There is no gap in 18b. Therefore, the molten elastomer injected into the cavity 17 does not leak out, and the grommet having a desired shape can be surely formed.

The dies 16A and 16B are not limited to the case in which the harness diameter D1 is 25 mm as described above.
Can be shared even if they are different. That is, when the harness diameter D1 is large, the number of turns of the heat-insulating flexible member 11 is reduced, while when the harness diameter D1 is small, the number of turns of the heat-insulating flexible member 11 is increased, thereby increasing the diameter of the grommet forming portion. If D2 is fixed, one mold can be shared for wire harnesses 4 having different diameters. In this case, if the diameter D2 of the grommet forming portion is set to be about 1 to 5 mm from the diameter D3 of the pipe formed by the wire harness insertion grooves 18a and 18b, the heat insulating flexible member 11 can be surely connected to the wire harness insertion groove. 18a,
18b, so that the resin can be prevented from flowing out of the cavity 17.

For example, as shown in FIG. 8A, when the diameter D1 of the wire harness 4 is 20 mm, the thickness t is 4 mm.
The heat-insulating flexible member 11 of about 2 mm is wound about two turns, and the diameter D3 of the grommet forming part is set to 36 mm. FIG.
As shown in (B), the diameter D1 of the wire harness 4 is 1
In the case of 5 mm, the heat insulating flexible member 11 having a thickness t of 5 mm
Twenty and a half turns to set the grommet molded part diameter to 35 mm.

The wrap portion 11c is connected to the wire harness 4
It is not always necessary to provide the heat insulating flexible member 11 over at least a part of the wire harness 4 surrounded by the heat insulating flexible member 11 so as to secure the waterproofness. What should I do?

FIGS. 9 and 10 show a second embodiment of the present invention. In the second embodiment, the heat insulating flexible member 1
As 1 ', a foamed EPDM sheet-like member having a thickness of about 7 mm provided with an adhesive layer on one surface is used. Also,
A heat-resistant tape 23 is wound around the outer periphery of the wire harness 4 around the entire length of the heat-insulating flexible member 11 ′. The sex member 11 ′ is fixed to the wire harness 4.

In the second embodiment, since the flexible heat insulating member 11 'and the heat resistant tape 23 are wound around the outer peripheral surface of the wire harness 4, the adhesive tape 3 and the electric wire of the wire harness 4 are heated by the heat of the molten resin. Can be prevented from dissolving, and the wire harness 4 at the edge 9 of the mold can be prevented.
Can be prevented from being damaged. Since the configuration and molding method of the second embodiment are the same as those of the first embodiment, the same members are denoted by the same reference numerals and description thereof will be omitted.

The present invention is not limited to the above embodiment, and various modifications are possible. First, the heat-resistant flexible member is not limited to the above-mentioned silicon rubber and foamed EPDM, but can protect the adhesive tape or the insulating coating portion of the electric wire from the heat generated by the molten resin material, and furthermore, the wire of the mold. Any material may be used as long as it has elasticity so as to be in close contact with the harness insertion groove.

Further, the resin material constituting the grommet is not limited to the above-mentioned elastomer, but may be EPD.
Various materials such as M and CR can be selected.

[0041]

As is clear from the above description, in the wire harness-integrated grommet according to the present invention, the heat insulating flexible member is wound around the outer peripheral surface of the wire harness so that at least a part thereof has a multilayer structure. Therefore, it is possible to prevent the adhesive tape in the cavity and the insulating coating portion of the electric wire from being melted by the heat of the molten resin at the time of filling the resin, and to prevent the occurrence of electrical problems due to the exposure of the conductor portion of the electric wire. be able to. Further, it is possible to prevent the adhesive tape near the mold from peeling off due to the heat of the molten resin.

Further, by winding the heat insulating flexible member around the wire harness as described above, it is possible to prevent the wire harness from being damaged at the edge of the mold when the wire harness is arranged in the mold.

Further, the diameter of the portion of the wire harness around which the heat-insulating flexible member is wound is set to be larger than the diameter of the tube formed by the wire harness insertion groove of the mold. The above-mentioned heat-insulating flexible member is elastically compressed and closely adhered to the wire harness insertion groove, thereby preventing the molten resin from flowing out of the cavity when filling the resin, and the wire harness is inserted into the wire harness insertion groove. It is possible to prevent bite and damage.

Furthermore, in the present invention, the number of turns of the heat insulating flexible member is set to be small for a wire harness having a large diameter, and the number of turns is set to be large for a wire harness having a large diameter. Since the diameter of the portion where the heat-insulating flexible member is wound can be constant, one mold can be shared when forming grommets on wire harnesses having different diameters, and cost can be reduced. It has various advantages.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a wire harness integrated grommet according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a schematic perspective view showing a heat insulating flexible member.

FIG. 4A is a schematic view showing a state where a heat insulating flexible member is wound around a wire harness, and FIG. 4B is a schematic view showing a state where an adhesive tape is wound around both ends of the heat insulating flexible member. .

FIG. 5 is a schematic view showing an operation of arranging a wire harness in a mold.

FIG. 6 is a schematic sectional view showing a state in which a wire harness is arranged in a mold.

FIG. 7 is a partial sectional view taken along line VII-VII in FIG. 6;

FIGS. 8A and 8B are schematic diagrams showing an example in which the number of turns of a heat insulating flexible member is changed in a wire harness.

FIG. 9 is a schematic perspective view showing a second embodiment of the present invention.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

FIG. 11 is a schematic sectional view showing a conventional grommet.

12A is a schematic perspective view for explaining a problem of a conventional grommet, and FIG. 12B is a cross-sectional view taken along line BB of FIG.

[Explanation of symbols]

 2 Electric wire 3,13 Adhesive tape 4 Wire harness 5,17 Cavity 6,16 Die 11,11 'Heat insulating flexible member 12 Grommet 23 Heat resistant tape

Claims (2)

(57) [Claims] 1. A grommet formed by resin molding has a sheet shape.
The heat-insulating flexible member at least partially has a multilayer structure
So that the wire harness-integrated grommet wiring harness wound around the outer peripheral surface by wrap characterized in that it is insert molded. (2)Corresponds to the shape of the grommet body to be molded
Cavities with the shape of
A pair with a continuous wire harness through groove
Insert mold the wire harness
It is a method of integrally molding with the grommet,  On the outer peripheral surface of the required part of the wire harness,Sheet-likeInsulation
Flexible membersSo that at least part of it has a multilayer structure
The heat insulating flexible member has an outer diameter
The pipe formed by the wire harness insertion groove of the pair of molds
Set larger than the diameter,  Glue the wire harness around which the heat-insulating flexible member is wound.
By penetrating the inside of the cavity of the
And a wire harness insertion groove continuous with both sides of the cavity.
The resin is filled into the cavity of the above mold by elastic pressure welding,
Grommets are formed integrally on the outer peripheral surface of the heat-insulating flexible member.
Forming grommet with integrated wire harness
Law.