AU2002300704B2

AU2002300704B2 - Grommet

Info

Publication number: AU2002300704B2
Application number: AU2002300704A
Authority: AU
Inventors: Hiroyuki Nakata
Original assignee: Sumitomo Wiring Systems Ltd
Current assignee: Sumitomo Wiring Systems Ltd
Priority date: 2001-09-12
Filing date: 2002-08-22
Publication date: 2008-01-31
Anticipated expiration: 2022-08-22
Also published as: JP4172535B2; JP2003087945A

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Sumitomo Wiring Systems, Ltd.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.

INVENTION TITLE: Grommet The following statement is a full description of this invention, including the best method of performing it known to me/us:- FP02-091AU BACKGROUND OF THE INVENTION This invention relates to a grommet and more particularly relates to a grommet that contains an electric wire assembly arranged between a vehicle body (car body) for an automobile and a door to be opened and closed to the car body such as a right or left door, or a luggage door in order to prevent the electric wire assembly from being broken by repeated bending loads caused in connection with closing and opening actions of the door.

For convenience of explanation, a prior art grommet will be described by referring to Figures 9 to 11. Figure 9 is a perspective view of the part of a prior art grommet arranged on components. Figure 10 is a perspective view of the prior art grommet. Figures 11 and are sectional views of main parts of the prior art grommets.

In an automobile, as shown in Figure 9, a wire harness W/H is arranged between a car body 1 and a luggage door 2 to supply an electric power and electric signals to a lamp and the like provided on the luggage door 2.

The wire harness W/H arranged between the car body 1 and the door 2 is subject to exposure to water when the door is opened. A grommet 3 made of an elastic material such as a rubber or the like sheathes the wire harness W/H

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FP02-091AU to hide an exposed bad appearance of the wire harness and to protect the wire harness from damage.

As shown in Figure 10, the grommet 3 includes a bellows-like tube 3a and major diameter tubes 3b and 3c that are provided on the opposite ends of the bellows-like tube 3a to be engaged with the car body. A resin inner 4 is attached to each of the major diameter tubes 3b and 3c.

A latch pawl 4a provided on an outer periphery of the resin inner 4 engages a peripheral edge around a throughhole formed in each of the car body and a door panel.

The wire harness W/H comprising a number of electric wire assemblies is passed through the grommet 3, with a part of the wire harness being secured to a tongue 3b-1 projecting from the major diameter tube 3b by winding a tape T around the part and tongue. As shown in Figure 9, the grommet 3 sheathing the wire harness W/H is disposed between the car body 1 and the door 2 while bending the bellows-like tube 3a. The bellows-like tube 3a changes a bending angle in compliance with closing and opening actions of the door 2 and follows the door 2 while being contracted and expanded.

A space S for accommodating the grommet 3, as shown in Figure 11 is limited. Consequently, it is necessary to bend, contract, and expand the bellows-like tube 3a in the limited space S. However, the bellows-like tube 3a cannot be always bended, contracted, or expanded in the space S. In a luggage door, as shown in Figure 11 the bellows-like tube 3a is likely to be buckled at 2 the area connected to the major diameter tube 3b at the door-engaging side. When the buckling occurs in the area, electric wires in the grommet 3 are subject to a concentric stress and are likely to be broken.

Such a trouble will occur in an area where the electric wires are arranged between the car body and the rear door or the like, or between the car body and a rotary panel of a door or the like as well as between the car body and the luggage door and are subject to repeated bending loads.

In order to prevent the buckling of the bellows-like tube, means for increasing a thickness of a portion in which a buckling will occur or for reinforcing troughs by infilling additional elements may be preferable. However, since the bellows-like tube is required for contraction and expansion, it will not be obtained to the contraction and expansion by merely reinforcing the bellows-like tube.

SUMMARY OF THE INVENTION In view of the above problem, an object of the present invention is to provide a grommet in which a bellows-like tube being subject to a repeated bending action can be protected against a buckling and a lowering of deformable function.

P XOPERLKA12S(4'A) M d-.23t2WM)7 -3A- In order to solve the above problems, the present invention provides a grommet to sheathe a wire harness extending from a vehicle body of an automobile to a door of the automobile, comprising: major diameter tubes provided on the opposite ends of said grommet, said major diameter tubes being adapted to respectively engage through-holes formed in a vehicle body panel and a door panel; and a bellows-like tube including troughs and crests connecting said major diameter tubes; said bellows-like tube being provided with a region of bending-restriction ribs that fill an outer periphery and/or an inner periphery of troughs on an area connecting to said major diameter tube at a door panel end, each of said ribs being provided on at least a central portion with a deformable slot.

Since the bending-restriction ribs fill the troughs on an end of the bellows-like tube where a bending stress tends to concentrate and the slots are formed in the ribs, the ribs spaced through the slot come into contact with each other when the end is bended, thereby preventing an over-bending of the end. The avoidance of the concentration of stress can reduce a local torsion and bending of the grommet, can eliminate a buckling of the grommet in a narrow space, and can prevent a break in the electric wires contained in the grommet.

Further, since the ribs provided on the end of the bellows-like tube have the deformable slots in the central portions of the ribs, the parts with ribs can be stretched in the same manner as the parts with no ribs. This does not deteriorate a contraction and expansion function of the grommet.

The ribs are disposed at an equal angular distance 4 FP02-091AU in a peripheral direction of each of said troughs and the slot is formed in a whole peripheral length of each of the ribs.

Thus, it is possible to prevent the bellows-like tube from being buckled even if a bending occurs in any direction in the bellows-like tube, since the plural ribs are disposed at an equal angular distance in the periphery of the tube. It is also possible to reduce a cost of material by forming the ribs spaced in the peripheral direction in comparison with continuous ribs in the periphery of the grommet. In addition, it is possible to maintain a good contraction and expansion of the bellowslike tube by providing the slots in the whole peripheral length of the ribs.

The ribs spaced in the peripheral direction have triangular or rectangular shapes that project from the central portions in the peripheral direction.

A handling and an appearance of the grommet will be improved by setting a height of the rib to be lower than the apex of the crest of a bellows-like configuration. It is possible to effectively prevent the buckling of the bellows-like tube by setting the height of the rib to be more than half of a height from the apex of the trough to the apex of the crest of the bellows-like configuration.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features of the present invention will become apparent to one skilled in the art FP02-091AU to which the present invention relates upon consideration of the i.nvention with reference to the accompanying drawings, wherein: Figure 1 is a front elevation view of a first embodiment of a grommet in accordance with the present invention; Figure 2 is a longitudinal sectional view of the grommet taken along line II-II in Figure 1; Figure 3 is a longitudinal sectional view of a main part of the grommet shown in Figure 1; Figure 4 is a cross sectional view of the grommet taken along line I-I in Figure 1; Figure 5 is a longitudinal sectional view of a main part of the grommet shown in Figure 1, illustrating the grommet to which an external force is applied; Figure 6 is a longitudinal sectional view of a main part of a second embodiment of a grommet in accordance with the present invention; Figure 7 is a longitudinal sectional view of a main part of a third embodiment of a grommet in accordance with the present invention; Figure 8 is a cross sectional view of a main part of a fourth embodiment of a grommet in accordance with the present invention; Figure 9 is a perspective view of a part of a prior art grommet arranged on components; Figure 10 is a perspective view of the prior art grommet; and FP02-091AU Figures 11 and are sectional views of main parts of the prior art grommets.

DEATAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a grommet in accordance with the present invention will be described below by referring to the drawings.

The grommet in the first embodiment sheathes a wire harness and is disposed between a vehicle body and a luggage door shown in Figure 9.

A first embodiment of a grommet 10 in accordance with the present invention is illustrated in Figures 1 to The grommet 10 comprises a bellows-like tube 11 and major diameter tubes 12 and 13 provided with the opposite ends of the bellows-like tubes 11 in the same manner as the grommet 3 shown in Figure 9. The grommet is integrally formed of a rubber material or an elastomer material.

The bellows-like tube 11 includes a bellows-like body llc having troughs 1la and crests lb that are arranged alternately, sleeve portions lid and lie having no trough and crest and provided on the longitudinally (axially) opposite ends of the body 1lc. The bellows-like tube 11 is connected to the major diameter tubes 12 and 13 through the sleeve portions lid and lie.

As shown in Figure 3, bending-restriction ribs llf and 1lg are formed on an end area P on the bellows-like 7 FP02-091AU tube 11 contiguous to the major diameter tube 12 to fill the troughs 1la. A deformable slot llh is formed between the ribs 1lf and 11g.

The ribs 1lf and 11g, as shown in Figure 4, are provided at eight positions equally spaced in the peripheral direction of the bellows-like body llc and have triangular shapes in section.

The major diameter tubes 12 and 13 include annular recesses 12a and 13a (see Figure 2) for engaging the resin inners 4 for car body engagement that are the same as those shown in Figure 10, and seal lips 12b and 13b (see Figure 2) on the distal ends of the major diameter tubes 12 and 13. When the grommet is attached to the car body, the seal lips 12b and 13b press the panel surface, thereby ensuring a waterproofing function.

A tongue 14 (see Figure 2) projects from an inner surface of the sleeve portion lid to extend outwardly through an opening of the major diameter tube 12.

Even if an external force F is applied to the end area P of the bellows-like tube 11 where a bending stress is apt to concentrate on account of a complex bending of the grommet 10, as shown in Figure 5, the opposed ribs llf and 1lg come into contact with each other and interfere with each other, thereby avoiding an over-bending of the grommet and preventing a buckling of the grommet disposed in a narrow space. Accordingly, it is possible to absorb a local torsion or bending of the grommet 10 and prevent a break in the electric wires inserted into the grommet 8 FP02-091AU Further, since the deformable slots llh are provided between the ribs 1lf and 1lg formed on the end area P on the bellows-like body llc, the bellows-like body llc having the area P can be stretched in the same manner as the bellows-like body having no ribs. This does not deteriorate a contraction and expansion of the grommet It is also possible to prevent the bellows-like body 1lc from being buckled against a bending in any direction by providing the ribs 1lf and 1lg spaced equally on the periphery of the body 1lc. It is possible to reduce a cost of material by spacing the ribs 1lf and 1lg in the peripheral direction in comparison with the case of providing the ribs along the whole periphery of the body.

The ribs 1lf and 1lg may project from the bellowslike body llc in either a rectangular shape or a triangular shape having an apex at the center.

Figure 6 shows a second embodiment of a grommet in accordance with the present invention.

The second embodiment of the grommet differs from the first embodiment of the grommet in the fact that the ribs are provided on not the outer periphery of the troughs 1la but the inner periphery of the crests llb.

Bending-resistant ribs llf' and llg' project inwardly to fill the inner periphery of the crests 1lb on the end area P of the bellows-like tube 11 contiguous to the major diameter tube 12. A deformable slot llh' is formed between the ribs llf' and lg'.

The above construction of the second embodiment of 9 FP02-091AU the grommet can maintain the same contraction and expansion as those of the first embodiment of the grommet and prevent the buckling, although the second embodiment of the grommet has no rib on the bellows-like tube at first glance.

Since the other structures of the second embodiment of the grommet are the same as those of the first embodiment of the grommet, explanations of them will be omitted here.

Figure 7 shows a third embodiment of a grommet in accordance with the present invention.

The third embodiment of the grommet differs from the first embodiment of the grommet in the fact that the ribs are provided on not only the outer periphery of the troughs :Lla but also the inner periphery of the crests lb.

Bending-resistant ribs 1lf and 1lg project outwardly to fill the outer periphery of the troughs 1la on the end area P of the bellows-like tube 11 contiguous to the major diameter tube 12 while bending-resistant ribs 1lf' and 1lg' project inwardly to fill the inner periphery of the crests lb on the end area P of the bellows-like tube 11 contiguous to the major diameter tube 12. Deformable slots 11h, and 1lh' are formed between the ribs 1lf and llg and between the ribs 1lf' and 1lg', respectively.

The above construction of the third embodiment of the grommet can enhance a buckling-resistant function and maintain the same contraction and expansion as that of the first embodiment of the grommet due to provision of the FP02-091AU slots 11lh and llh'.

Since the other structures of the third embodiment of the grommet are the same as those of the first embodiment of the grommet, explanations of them will be omitted here.

Figure 8 shows a fourth embodiment of a grommet in accordance with the present invention.

The fourth embodiment of the grommet differs from the first embodiment of the grommet in the fact that bending-resistant ribs llf" projecting from the troughs lla" to fill them have rectangular shapes in section.

The ribs 1lg" (not shown) are provided through the deformable slot behind the ribs llf" in the inner part of Figure 8 by the same manner as that in the first embodiment.

The ribs llf" and llg" are provided on six portions equally spaced on the periphery of the bellows-like tube 11.

Since the other structures of the fourth embodiment of the grommet are the same as those of the first embodiment of the grommet, explanations of them will be omitted here.

From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.

The entire disclosure of Japanese Patent Application 11 FP02-091AU No. 2001-276604 filed on September 12, 2001 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims

2. A grommet according to Claim 1, wherein a plurality of ribs are disposed at an equal angular distance in a peripheral direction of each of said troughs and said slot being formed in a whole peripheral length of each of said ribs.
3. A grommet according to Claim 1 or 2, wherein a height of said rib is lower than an apex of the crest of said bellows-like configuration and more than half of a height from the apex of the trough to the apex of the crest of the bellows-like configuration.
4. A grommet according to Claim 2 or 3, wherein said rib has a triangular or rectangular shape that projects from a P \OPERLKA2564) Ipc- dom-23AWn/217 -14- central portion. A grommet according to any one of Claims 1 to 4 further comprising sleeve portions disposed either side of said bellows-like tube and respectively adjacent said opposite ends, said sleeve portion being free of said troughs and crests.
6. A grommet according to Claim 5 wherein said region of bending-restriction ribs extends continuously from the respective sleeve portion.
7. A grommet to sheathe a wire harness extending from a vehicle body of an automobile to a door of the automobile, said grommet substantially as described with reference to the accompanying drawings.