JPH09289725A - Grommet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To intercept and suppress the sound leakage into a cabin by improving the sound insulating performance of a grommet. SOLUTION: A grommet is constituted by the double-layer molding of a flexible foam body 11 and rubber 12 or elastomer which covers the whole surface of the foam body 11. Or, the grommet is constituted of a peripheral member consisting of rubber or elastomer and a filler member consisting of the flexible foaming body being set inside that peripheral member and also having a cable passage hole, thus the sound insulation is made by absorbing the sound with the foam body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grommet for an automobile, and more specifically, to a grommet attached to a wire harness penetrating a vehicle body panel or the like that separates an engine room and an interior side from the vehicle body panel. In the case of waterproofing, dustproofing, etc. by interposing it, the sound insulating performance is also improved.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, this type of grommet has a small diameter cylindrical reduced portion 1 made of rubber or an elastomer, which is brought into close contact with the outer peripheral surface of a wire harness, and one end of the reduced diameter portion 1. It has a configuration in which a diameter-expanded portion 2 that expands into a conical cylinder shape is integrally molded. A wire harness W obtained by bundling the wire group w with the tape T1 on the grommet 3.
/ H is penetrated, and the tape T2 is strongly wound around the outer peripheral surface of the reduced diameter portion 1 to be attached. Grommet 3 like this
The wire harness W / H attached with the grommet 3 is passed through the through hole 4a of the vehicle body panel 4 at the time of wiring to the automobile.
A locking recess 2a provided on the outer peripheral surface of the expanded diameter portion 2 is locked and attached to the through hole 4a.

[0003]

[Problems to be Solved by the Invention] The above wire harness W
Since / H is routed from the engine room side X to the room side Y, the grommet 3 once inserts the entire enlarged diameter portion 2 into the room side Y, and then pulls it back to the engine room side X. It is necessary to lock the stop recess 2a in the through hole 4a of the vehicle body panel 4. Therefore, the expanded diameter portion 2 is bent and the through hole 4
Since it is necessary to pass it through a, the inclined portion 2b of the expanded diameter portion 2 is thin.

Therefore, an incident sound (indicated by a solid arrow in the figure) composed of noise on the engine room X side is transmitted to the inside of the grommet 3 through the thin-walled expanded portion 2 and the transmitted sound (indicated by a dotted arrow in the figure). (Shown) penetrates into the indoor side Y through the space S between the inner peripheral surface of the grommet 3 and the outer peripheral surface of the wire harness W / H inside the expanded diameter portion 2 of the grommet 3. As described above, the conventional general grommet does not pay particular attention to the sound insulation performance, so that the sound insulation performance is low, the noise leaks from the wire harness insertion portion into the room, and the comfort performance in the vehicle interior is reduced. there were.

In order to improve the sound insulation performance, as shown in FIG. 9, there is one in which the solid body 6 made of a rigid body is inserted into the inner space of the expanded diameter portion 2 of the grommet 3 to seal the space. When the wire harness is inserted, the work of penetrating the wire harness W / H is not easy and there is a problem that the workability is impaired. Further, a structure has been proposed in which the space is filled with a sealing agent, but there is a problem that the sealing agent filling operation is troublesome. In addition, the grommet is hardly bent by the solid body 6 or the hardened sealant, so that the workability of inserting the grommet into the vehicle body panel is deteriorated. There is also a problem that the cable workability is deteriorated. As described above, when the sound insulation performance is to be improved, the workability is deteriorated, and the compatibility cannot be easily achieved.

The present invention has been made in view of the above problems, and a grommet capable of improving the sound insulation performance without impairing the flexibility of the grommet and the bendability of the wire harness, and without requiring the labor. It is intended to be provided.

[0007]

In order to achieve the above object, the present invention provides a reduced diameter portion of a cylindrical shape having a small diameter and an enlarged diameter portion extending from one end of the reduced diameter portion into a conical cylindrical shape. The wire harness that bundles the wire group is closely contacted with the wire insertion hole provided along the axis of the reduced diameter portion and the enlarged diameter portion, and the vehicle body is locked to the outer peripheral portion of the enlarged diameter portion. In the grommet provided with the recess, the grommet,
Provided is a grommet characterized by being formed by two-layer molding of a flexible foam and a rubber or an elastomer covering the entire surface of the foam.

According to the structure of the above-mentioned claim 1, since the incident sound can be absorbed by the pores of the foamed body which constitutes the entire grommet, the sound insulation performance can be improved. Further, since the outer peripheral surface, the inner peripheral surface, and the outer surfaces of both end surfaces of the foam are entirely covered with rubber, it is possible to suppress the incidence of noise from the engine room side and the like and the permeation of the incident sound to the indoor side. Moreover, since the foam is formed by two-layer molding in which the entire outer surface of the foam is covered with rubber, the foam can be easily manufactured. further,
Since the grommet is made of foam and rubber, the grommet does not impair its flexibility, does not impair the workability of attaching it to the vehicle body panel, and does not impair the flexibility of the wire harness that is inserted into the grommet. It does not reduce the workability.

According to a second aspect of the present invention, there is provided a cylindrical reduced-diameter portion having a small diameter, and an enlarged-diameter portion expanding from one end of the reduced-diameter portion into a conical cylindrical shape. In the grommet in which the wire harness that bundles the electric wire groups is brought into close contact with the electric wire insertion hole provided along the axis of the section and the vehicle body locking recess is provided in the outer peripheral portion of the expanded diameter portion, the grommet is A grommet comprising: an outer peripheral member made of rubber or elastomer; and a filling member made of a flexible foam that fits inside the outer peripheral member and has the wire insertion hole at the center. Are offered.

According to the structure of claim 2, since the filling member is made of foam, the foam can absorb incident sound, and the sound insulation performance can be improved as in the case of claim 1.
Further, the grommet of claim 2 is different from the grommet of claim 1, and since it is only necessary to internally fit a filling member made of a foam inside a conventionally provided grommet made of rubber or elastomer, it is easier to manufacture. can do.
Moreover, since it is a foam, it does not impair the flexibility of the grommet and the bendability of the wire harness to be inserted.

It is preferable to increase the wall thickness of the enlarged diameter portion of the outer peripheral member made of rubber or elastomer and to provide a groove on the inner peripheral surface thereof to facilitate bending. (Claim 3) As described above, when the rubber or elastomer of the expanded diameter portion where noise is likely to enter is made thick, the sound insulation performance can be further enhanced. Further, if the wall thickness is increased, the expanded diameter portion becomes difficult to bend, but since the groove, preferably a plurality of annular grooves is provided on the inner peripheral surface thereof, the grommet easily bends,
Does not reduce the workability of mounting on the vehicle body panel.

It is preferable that the wire group of the wire harness that penetrates the wire insertion hole has an outer peripheral surface wound with a tape and a sealant filled therein. (Claim 4) By thus filling the inside of the wire harness with the sealant, it is possible to prevent noise that tries to enter through the gap of the wire group, and further improve the sound insulation performance. In addition, the waterproof performance can be improved by filling the sealant. Also as this sealing agent, a two-liquid sealing agent such as urethane is preferable.

The foam is made of a flexible foam made of resin or rubber containing EPDM rubber or urethane foam. (Claim 5) The rubber is preferably butyl rubber or the like.

[0014]

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

FIGS. 1 to 4 show a first embodiment. A grommet 10 of the first embodiment is a two-layer molding in which a foam 11 made of EPDM rubber is entirely covered with a thin rubber 12 made of butyl rubber. It consists of goods. The foam 11 having a large number of small holes 11a as shown in FIG. 3 is preferably used because it has excellent sound absorbing performance.

The entire outer surface of the foam 11 is covered with a thin rubber 12
The shape of the grommet 10 covered with is composed of a cylindrical reduced diameter portion 13 and an enlarged diameter portion 14 expanding from one end of the reduced diameter portion 13 into a conical tubular shape. The wire harness W / H in which the wire group w has been bundled with the tape T1 is made to closely penetrate the wire insertion hole 16 provided along the axis of the above, and the vehicle body locking recess 15 is provided on the outer peripheral portion of the expanded diameter portion 14. It is provided.

As shown in FIG. 3, the vehicle body locking recess 15 is annularly recessed in the enlarged end of the inclined portion 14a of the expanded diameter portion 14, and the diameter is increased from the tip end side of the vehicle body locking recess 15. The indoor locking portion 14b is provided so as to project. Car body locking recess 15
The rubber 12 that covers the bottom surface of the
As shown in FIG. 12, the protrusion 12a is formed on the outer peripheral surface of the collar portion 4b which is bent from the through hole 4a of the vehicle body panel 4 toward the engine room side X.
Is pressed.

With respect to the grommet 10, the wire harness W / H is, as shown in FIG.
Wire harness W / with the reduced diameter part 13 expanded
H is inserted from the connector 19 side attached to the tip. At that time, the grommet 10 has flexibility and stretchability and is easily spread only by covering the outer surface of the foam 11 with the thin rubber 12, and the workability of inserting the wire harness W / H is not impaired. .

After passing the wire harness W / H through the grommet 10 in the above state, as shown in FIG.
2 from the end of the outer peripheral surface of the reduced diameter portion 13 to the wire harness W /
The wire harness W / H is wound around the outer peripheral surface of H and positioned and fixed to the grommet 10.

When the wire harness W / H to which the grommet 10 is attached is inserted into the through hole 4a of the vehicle body panel 4, the entire enlarged diameter portion 14 of the grommet 10 is once inserted from the engine room side X to the room side Y. At this time, it is necessary to bend the expanded diameter portion 14 so as to have a small diameter, but this work can also be performed without problems because the grommet easily bends. After the expanded diameter portion 14 is inserted into the indoor side Y, it is pulled back to the engine room side X and the vehicle body locking recess 15 is locked in the through hole 4a. At that time, the protrusion 12a is pressed by the collar portion 4b to improve the sealing property.

The grommet 10 attached to the vehicle body panel 4 as described above absorbs sound in the pores 11a of the foam 11 even if noise enters from the engine room side X and leaks sound to the room side Y. Suppress. When the inventor conducted an experiment,
It was possible to completely prevent the sound of about 5 dB from leaking from the engine room side X to the room side Y. Further, in the case of noise of 5 dB or more, sound leakage to the indoor side could be reduced by about 5 dB.

FIG. 5 shows the second embodiment. The difference from the first embodiment is that, with respect to the wire harness W / H inserted through the grommet 10, a sealing agent 20 such as urethane is applied from the side of the reduced diameter portion 13 side. The sealant 20 is mainly filled in the gap between the wire groups w of the wire harness W / H located inside the reduced diameter portion 13. Grommet 10 itself is the first
It is the same as the embodiment.

As described above, when the gap between the wire groups w of the wire harness W / H is filled with the sealant 20, noise that enters through the gap between the wire groups w can be prevented and the sound insulation performance can be further improved.

FIG. 6 shows a third embodiment. In the grommet 33 of the third embodiment, a filling member 30 made of foam is closely attached to the inside of an outer peripheral member 31 having the same shape as the grommet shown in FIG. 8 of the conventional example. It is the one that was fitted inside in the state of being. That is, the filling member 30 made of a foam material has a reduced diameter portion 30a that is closely attached to the inner surface of the reduced diameter portion 1 made of rubber or elastomer.
And an enlarged diameter portion 30b that is brought into close contact with the inner surface of the enlarged diameter portion 2, and a wire insertion hole 30c is provided from the reduced diameter portion 30a to the axis of the enlarged diameter portion 30b. The filling member 30 and the outer peripheral member 31 may be formed by molding the filling member 30 and then forming the outer peripheral member 31 on the outer periphery of the filling member 30. Alternatively, the filling member 30 and the outer peripheral member 31 may be separately molded, and the filling member 30 may be pushed into the outer peripheral member 31 and fixed with an adhesive.

When the grommet 33 of the third embodiment is used, the sound input performance can be improved by absorbing the incident sound by the filling member 30 made of foam as in the first embodiment. Further, when the outer peripheral member 31 having the same shape as the conventional grommet is used and is molded separately from the filling member 30, the conventional grommet can be used as it is, and the production cost of the grommet is prevented from increasing. it can.

FIG. 7 shows a grommet 40 of the fourth embodiment, which, like the grommet 33 of the third embodiment, is composed of a combination of an outer peripheral member 41 made of rubber or elastomer and a filling member 42 made of foam. The difference between the grommet 40 of the fourth embodiment is that the expanded diameter portion 41 of the outer peripheral member 41.
The thickness t of the inclined portion 41b of a is increased and the inclined portion 4
A grooved annular groove 41e is provided on the inner peripheral surface at a position extending from 1b to the vehicle body locking recess 41c, and further,
The point is that an annular groove 41f is similarly provided on the inner peripheral surface at a position where the vehicle body locking recess 41c is engaged with the indoor locking portion 41d. Further, a protrusion 41h is provided on the bottom surface of the vehicle body locking recess 41c.

In the grommet 40, on the engine room side, since the inclined portion 41b of the enlarged diameter portion having the largest surface area of the outer peripheral member 41 has a large thickness, the noise incident on the grommet 40 is first to some extent. Can be shut off. Further, as in the other embodiments, the sound that is incident can be absorbed by the holes of the filling member 42 made of foam, and the sound insulation performance can be maximized.

Further, the inclined portion 41 of the enlarged diameter portion of the outer peripheral member 41
Since the wall thickness of b is large, compared with the case of thin wall,
Although it is difficult for the grommet 40 to bend, the grommet 40 can be easily bent as in the case where the grommet 40 is thin because the annular grooves 41e and 41f are provided in front of and behind the vehicle body locking recess 41c. Therefore, the workability of inserting the vehicle body panel into the through hole is not deteriorated.

[0029]

As is apparent from the above description, in the grommet according to the present invention, since the foam which can absorb the sound by the pores is used and the entire outer surface or the outer peripheral surface is covered with the rubber or the elastomer, the sound insulation is achieved. Performance can be improved and strength can be maintained.

Furthermore, since the foam has flexibility, even if the foam is filled inside, the flexibility of the grommet is not impaired, and the workability of inserting the wire harness into the grommet is improved.
In addition, it is possible to achieve both sound insulation and workability without impairing the workability of inserting the grommet into the through hole of the vehicle body panel.

Furthermore, when the wire group of the wire harness which is inserted into the grommet is filled with a sealant, noise can be prevented from entering through the gap between the wire groups, and the sound insulation performance can be further improved.

Particularly in automobiles, it is very important to prevent noise from entering the interior of the vehicle in order to improve the comfort performance of the living space in the passenger compartment. The point is to eliminate or suppress leakage. By using the grommet of the present invention, it is possible to almost completely block low noise and suppress loud noise as well, thereby preventing and suppressing sound leakage into the vehicle interior and improving comfort performance. Can be.

[Brief description of drawings]

FIG. 1 is a perspective view of a grommet according to a first embodiment of the present invention.

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

FIG. 3 is a partially enlarged view of FIG.

FIG. 4 is a schematic cross-sectional view showing the work of inserting the wire harness into the grommet.

FIG. 5 is a cross-sectional view showing a state in which a wire harness has been inserted through the grommet of the second embodiment of the present invention.

FIG. 6 is a sectional view showing a grommet according to a third embodiment of the present invention.

FIG. 7 is a sectional view showing a grommet of a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state in which a wire harness is inserted through a conventional grommet.

FIG. 9 is a cross-sectional view showing another conventional grommet.

[Explanation of reference numerals] 4 vehicle body panel 4a through hole 10, 33, 40 grommet 11 foam 12 rubber 13 reduced diameter portion 14 expanded diameter portion 15 vehicle body locking recess 30, 42 filling member 31 made of foam rubber or elastomer Outer peripheral member 41b composed of thick-walled inclined portions 41e, 41f annular groove

Claims (5)

[Claims] 1. A cylindrical reduced diameter portion having a small diameter and an enlarged diameter portion expanding from one end of the reduced diameter portion into a conical cylindrical shape, and provided along the axis of the reduced diameter portion and the enlarged diameter portion. In a grommet in which a wire harness having a bundle of electric wires is closely contacted with the electric wire insertion hole and penetrated, and a vehicle body locking recess is provided on an outer peripheral portion of the expanded diameter portion, the grommet is formed of a flexible foam, A grommet characterized by being formed by two-layer molding with a rubber or an elastomer covering the entire surface of the foam. 2. A cylindrical reduced diameter portion having a small diameter and an enlarged diameter portion expanding from one end of the reduced diameter portion into a conical cylindrical shape, and provided along the axis of the reduced diameter portion and the enlarged diameter portion. In a grommet in which a wire harness in which a group of electric wires is bundled is tightly passed through the electric wire insertion hole and a vehicle body locking recess is provided in an outer peripheral portion of the expanded diameter portion, the grommet is an outer peripheral member made of rubber or elastomer, A grommet characterized by comprising a filling member made of a flexible foam which fits inside the outer peripheral member and has the electric wire insertion hole at the center thereof. 3. The grommet according to claim 2, wherein the outer peripheral member made of rubber or elastomer has a large thickness at the enlarged diameter portion and a groove for facilitating bending is provided on the inner peripheral surface thereof. 4. An electric wire group of a wire harness which penetrates through the electric wire insertion hole has an outer peripheral surface wound with a tape, and a sealing agent is filled inside the electric wire group.
The grommet according to any one of 1. 5. The grommet according to claim 1, wherein the foam is made of resin or rubber containing EPDM rubber or urethane foam.