Electricity: conductors and insulators – Insulators – Through wall or plate
Reexamination Certificate
2000-03-01
2002-01-15
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Insulators
Through wall or plate
C016S002100, C248S056000
Reexamination Certificate
active
06339196
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a grommet that engages around an outer periphery of a wire harness for an automobile and is mounted in a through hole of an automobile body panel. In particular, this invention improves seal efficiencies by providing plural contact points between the automobile body panel and the grommet.
2. Description of Related Art
Conventionally, when a wire harness for an automobile is inserted into a through hole provided in an automobile body panel that divides an engine compartment and a passenger compartment, in order to wire the wire harness, the wire harness is inserted into a grommet which is made of a rubber. The grommet is provided with a generally conical (convex) portion with a recess for engaging with the automobile body and a small-diameter cylindrical portion that extends from the tip end of the conical portion and tightly engages around an outer peripheral surface of the wire harness. Then, the grommet with the wire harness is mounted in the through hole. The recess for engaging with the automobile body contacts the edge of the through hole of the automobile body panel to prevent water intrusion from the through hole.
When a burring is not protrusively provided around the through hole of the automobile body panel, a grommet
1
as shown in FIGS.
6
(A)-
6
(C) is used. The grommet
1
is provided with a small-diameter cylindrical portion
1
a
to tightly cover a wire harness, a generally conical portion
1
b
extending from one end of the small-diameter cylindrical portion
1
a
. A conical portion has a thickened portion around an enlarged end of the conical portion. The recess
1
c
for engaging with an automobile body panel is provided on an outer periphery of the thickened portion. One side wall
1
g
of the recess in the enlarged end of the conical portion extends outwardly and a lip
1
d
is provided on the tip of the extending side wall.
A width W
1
of the recess
1
c
(the distance between side walls if and
1
g
) is defined to be slightly larger than a panel thickness W
2
of an automobile body panel
2
to make the grommet easier to mount on the automobile body panel and to provide versatility such that the grommet can be used with an automobile body panel having a variety of the panel thicknesses W
2
. As described above, the lip
1
d
is provided and pressed against the automobile body panel
2
. Further, the diameter D
1
of the grommet around the bottom surface
1
e
of the recess
1
c
is defined such that an entire inner peripheral surface
2
a
-
2
of the through hole
2
a
contacts the bottom surface
1
e
of the recess
1
e
. In other words, the diameter D
1
is defined to be at least as large as the diameter D
2
of the through hole
2
. More specifically, when D
2
is 55 mm, D
1
is set to be about 55 mm plus 0 mm to 0.3 mm.
Thus, to secure a seal efficiency, the recess
1
c
of the grommet
1
and the automobile body panel
2
which engages with the inner surface of the recess
1
c
, contact each other at three points P
1
, P
2
and P
3
as shown in FIG.
6
(C). In other words, the entire inner peripheral surface
2
a
-
2
of the through hole
2
a
contacts the bottom surface
1
e
of the recess
1
c
at P
1
, the lip
1
d
contacts panel
2
at P
2
, and the automobile body panel
2
is pressed against the side wall
1
f
of the recess
1
c
at P
3
by the lip
1
d.
However, as shown in
FIG. 7
, for example, when a wire harness fitted with the above-described grommet is inserted into the through hole
2
a
from an engine compartment side (X) to a passenger compartment side (Y), the wire harness is often forced to bend in the engine compartment side (X). Thus, when the wire harness W/H is bent, the grommet
1
, which is fixed to the wire harness by taping at the small-diameter cylindrical portion
1
a
, is also forced to bend. Therefore, at a side opposite to the bending direction ((Z) in FIG.
7
), as shown in
FIG. 8
, the inner peripheral surface
2
a
-
2
of the through hole
2
a
becomes separated from the bottom surface
1
e
of the recess
1
c
. In addition, the side wall if on the small-diameter cylindrical portion side is pulled and is sometimes separated from the automobile body panel
2
. Thus, only the lip
1
d
contacts the automobile body panel
2
, and the original three contact points for sealing are reduced to one. As a result, water can easily enter the passenger compartment side (Y) and, in the worst case, water does intrude into the passenger compartment side (Y).
Accordingly, the present invention is provided to overcome the above-described problems. The objective of the present invention is to provide a grommet that contacts the automobile body panel at plural points instead of only one sealing point in the lip and thus ensures waterproofness, even when the grommet is pulled in a direction due to bending of the wire harness.
SUMMARY OF THE INVENTION
To achieve the above and other goals, the present invention provides a grommet that engages around an outer periphery of a wire harness and is mounted on a through hole of an automobile body panel without burring. The grommet of the present invention includes a generally cylindrical portion that tightly covers wires of the wire harness. A generally conical portion extends from one end of the cylindrical portion. A thickened portion is provided around the conical portion in an enlarged end. A recess for engaging with the automobile body is provided on the outer peripheral surface of the thickened portion. A first side wall of the recess in the enlarged end extends outwardly, and a lip projects from a tip of the first side wall. A bottom surface of the recess has one of a curved portion and an inclined portion so that an edge of the through hole is forcefully pressed into and distorts the curved or inclined portion. A second side wall of the recess faces the first side wall and is formed so as to approach the first side wall along a direction from the bottom surface to an opening end of the recess. Thus, the automobile body panel, which engages with the inner surface of the recess of the grommet of the present invention, contacts the curved portion or inclined portion of the recess and the second side wall, as well as the lip
As described above, the bottom surface of the recess configured to be engaged with the automobile body has a curved or inclined portion, and the edge of the through hole is forcefully pressed into and distorts the curved or inclined portion. Therefore, even if the grommet is pulled in a direction such that the inner peripheral edge of the through hole is separated from the bottom surface of the recess, the inner peripheral edge of the through hole engages and remains in contact with the curved or inclined surface. Further, since the side wall that faces the lip-side side wall is formed so as to approach the lip-side side wall, the automobile body panel is pressed by the lip and contacts the side wall that faces the lip-side side wall. Accordingly, together with the contact between the lip and the automobile body panel, the grommet and the automobile body panel remain in contact with each other at three points.
When the grommet is strongly pulled and sharply bent, the side wall that faces the lip-side side wall may be pulled in the bending direction and may be separated from the automobile body panel. Even in that case, since the bottom surface of the recess is curved or inclined in a V-shape, and the inner peripheral edge of the through hole is forcefully pressed into and distorts the curved or inclined bottom surface, the contact therebetween is maintained. Thus, together with the contact by the lip, at least two contact points are ensured. Accordingly, unlike the prior art device, since there is no chance for the grommet of the present invention to contact with the automobile body panel at only one contact point, seal efficiency is improved compared with the prior art device.
In accordance with another aspect of the present invention, the lip projects in a direction toward the cylindrica
Greenblum & Bernstein P.L.C.
Nino Adolfo
Reichard Dean A.
Sumitomo Wiring Systems Ltd.
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