Electricity: conductors and insulators – Conduits – cables or conductors – Single duct conduits
Reexamination Certificate
2002-05-16
2004-06-01
Patel, Dhiru R (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Single duct conduits
C174S068300, C174S655000, C174S135000, C016S002100, C248S056000
Reexamination Certificate
active
06743981
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a waterproof structure of an electric junction box, in which a grommet for waterproof is mounted thereon to guide a wiring harness out from the junction box, thereby preventing water from entering into the junction box.
(2) Description of the Related Art
FIG. 11
illustrates a typical example of a conventional waterproof structure of an electric junction box.
The electric junction box (hereinafter, junction box) includes a case
71
made of synthetic resin, a cover
72
made of synthetic resin, a junction unit (not shown) including a fuse, relay and so on, which is received in the case
71
, and a resilient grommet
73
for waterproof. A U-shaped notch
74
for guiding out a wiring harness is formed on one side wall of the case
71
and a guide member
75
is formed projectingly outward from the periphery of the notch
74
. The grommet
73
slidingly fits into the guide member
75
so that the wiring harness (a plurality of wires)
76
continuing to the junction unit (not shown) is inserted through the grommet
73
and guided out therefrom.
The grommet
73
includes a bellows
77
, a cylinder
78
having small diameter continuing to one end of the bellows
77
, a flange
79
continuing to the other end of the bellows
77
, and a reinforcing member (not shown) made of synthetic resin fit into the flange
79
. The flange
79
slidingly fits into the guide member
75
of the case
71
and the cover
72
covers the case
71
so as to make the upper surface of the flange
79
adhere to the lower surface of the cover
72
, thereby preventing water from entering into the case
71
from the outer periphery of the flange
79
.
A rectangular annulus packing (not shown) is provided on the inner periphery of the cover
72
and the upper edge of the case
71
adheres to the packing, thereby preventing water from entering from the junction between the case
71
and cover
72
. The end of the cylinder
78
of the grommet
73
is wound with a vinyl tape (not shown) after the wiring harness
76
is inserted through the grommet
73
, thereby preventing water from entering.
However, in the conventional waterproof structure of a junction box, for example in a case of truck, in which the junction box is mounted thereon being exposed to outside, when rainwater leaped up during traveling, water during vehicle washing or high-pressure water during vehicle washing with the high-pressure water directly hits the flange
79
of the grommet
73
, the water enters between the flange
79
and case
71
or cover
72
, thereby causing a problem. In the event that water enters into the case
71
, the water possibly adversely affects the junction unit and so on in the case
71
.
On the other hand, in Japanese Patent Publication No. H8-288667 (not shown in the figure) described is a structure, in which the case is formed with double walls and each wall fits into the flange of the waterproof grommet. However, in this case, the waterproof structure becomes large in size and the structure of the grommet becomes complicated, thereby causing another problem.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to solve the above problems and to provide a waterproof structure of an electric junction box, by which rainwater, water during vehicle washing or high-pressure water during vehicle washing with the high-pressure water, which strongly hits the grommet, does not enter into the case and the waterproof structure can be minimized and simplified.
In order to attain the above objective, the present invention is to provide a waterproof structure of an electric junction box comprising:
a case including a notch and a guide member formed along the periphery of the notch;
a resilient grommet for inserting a wiring harness therethrough including a flange which fits into the guide member; and
a cover for covering the case from above the flange, wherein the flange includes at least two flange parts formed integrally with each other, a height and width of the first flange part situated relatively farther from the case being formed smaller than those of the second flange part situated relatively nearer to the case, respectively.
With the construction described above, even when water leaped up during traveling or high-pressure water during vehicle washing strongly hits the flange of the grommet and passes through the adherent portion of the first flange part, the first flange part weakens the water energy and the second flange part securely waterproofs the junction box.
Further, since the first and second flange parts are integrally formed with each other, the waterproof structure according to the present invention is simplified and minimized compared to a conventional grommet having double flanges fitting into double walls of a junction box body, thereby the junction box can be minimized.
Preferably, the case is provided with first and second guide walls fitting with the first and second flange parts, respectively, as the guide member.
With the construction described above, since each flange part is held by the corresponding guide wall, even when high-pressure water hits and bends the first flange part, the second flange part securely waterproofs the junction box without being affected by the water. Therefore, the waterproof performance is significantly improved.
Preferably, each top of the first and second flange parts projects higher than the guide member so that both said tops adhere to the cover.
With the construction described above, since the top of each flange part resiliently abuts against the cover, the top of the second flange part securely waterproofs the junction box even when water passes over the top of the first flange part.
Preferably, the top of the first flange part adheres to an inner surface of the cover while the top of the second flange part adheres to a packing in the cover.
With the construction described above, the first flange part directly adheres to the inner surface of the cover and resists against the high-pressure water with the strong adhering force. The second flange part resists against the water, the energy of which has been weakened, and waterproofs the junction box with the contact with the packing.
Thus, with the two-step shielding against water, the water is securely prevented from entering from between the flange and cover.
Preferably, a peripheral wall of the case is formed doubly inner and outer, the inner peripheral wall is formed higher than the outer peripheral wall, and the height of the first guide wall is set equal to that of the outer peripheral wall while the height of the second guide wall is set equal to that of the inner peripheral wall.
With the construction described above, even when water hits the outer peripheral wall and enters into the inside, the water is stopped by the high inner peripheral wall and prevented from entering into the inside of the inner peripheral wall. Further, the water which enters into the inside of the first guide wall hits the high second guide wall and thereby is prevented from entering further. Therefore, the cooperative action between each guide wall and the flange of the grommet significantly improves the waterproof performance.
Preferably, the bottom of the first guide wall is provided with a hole for draining water.
With the construction described above, water which enters inside the first guide wall is drained through the hole at the bottom, thereby the water pressure (i.e. water energy) which applies to the second flange part inside the second guide wall is reduced. Therefore, the second flange part securely waterproofs the junction box.
Preferably, the grommet is provided with a third flange part adjacently to the second flange part and the cover is provided with a third guide wall fitting with the third flange part.
With the construction described above, since the third flange part adheres to the third guide wall, the third flange part securely stops water in the event that the water passes through the second flange part. F
Armstrong Kratz Quintos Hanson & Brooks, LLP
Patel Dhiru R
Yazaki -Corporation
LandOfFree
Waterproof structure of electric junction box does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Waterproof structure of electric junction box, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Waterproof structure of electric junction box will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3316356