Information
-
Patent Grant
-
6787701
-
Patent Number
6,787,701
-
Date Filed
Thursday, October 4, 200122 years ago
-
Date Issued
Tuesday, September 7, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 174 65 G
- 174 65 R
- 174 65 SS
- 174 152 G
- 174 153 G
- 248 56
- 016 21
- 016 22
-
International Classifications
-
Abstract
The invention relates to a waterproof grommet having a first member (20) and a second member (30). The first member (20) has a first sealing part (22) formed on the inner surface of a through-hole (21) through which an electrical wire connected to a contact is passed. The first sealing part (22) adheres tightly to the electrical wire. The second member (30) has a second sealing part (32) formed on the outer surface of the through-holes (21) that adheres tightly to the connector housing (40). The first member (20) is formed from an elastic material that has a lower hardness than that of the second member (30). As a result, splitting of the inner surface of the through-holes (21) is prevented without causing any deterioration of the waterproof properties of the joint between the connector housing and the waterproof grommet.
Description
FIELD OF THE INVENTION
The present invention relates to a grommet, and more specifically, to a waterproof grommet assembly for a connector.
BACKGROUND
A conventional waterproof grommet is typically molded from a soft synthetic resin, such as rubber. Synthetic resins have elasticity and have a high degree of adhesion. The characteristics of the resin afford the grommet waterproofing properties and enable the grommet to be compressed so that it can be readily attached to a connector.
The use of a soft synthetic resin, however, is associated with a plurality of drawbacks. For example, when the grommet is compressed for attachment to a connector housing, the through-holes formed in the waterproof grommet are crushed and deformed by the compression causing the through-holes to shift. Further, in the case of a connector that has a plurality of contacts, if the plurality of contacts is inserted into the waterproof grommet in order from one side, a bias pressure is generated in the vicinity of the through-holes containing electrical wires. The pressure causes the through-holes into which electrical wires have not yet been inserted to shift. Because in either case the through-holes no longer correspond with the contact cavities, gaps are created between the waterproof grommet and the inner surface of the connector housing when contacts are inserted, causing the sealing properties of the waterproof grommet to deteriorate.
One method of addressing these drawbacks is shown in Japanese Utility Model Registration No. 2503949 (FIG.
4
). This Utility Model discloses a grommet with protruding parts
143
disposed inside a connector housing
140
that engage in recessed parts
123
of the waterproof grommet
111
. The assembly prevents the positions of the contact cavities
141
or through-holes
121
from shifting either when a compressive pressure is applied to the grommet or when a plurality of contacts are inserted from one side. Because a soft synthetic resin is used, however, when contacts connected to electrical wires are inserted into the through-holes of the grommet, splitting occurs on the inner surfaces of the through-holes. As a result, water is capable of entering the grommet through the split areas.
It is therefore desirable to develop a waterproof grommet, which reduces the splitting effects of the inner surfaces of the through-holes formed in the waterproof grommet without causing any deterioration of the waterproof properties.
SUMMARY OF THE INVENTION
This invention relates to a waterproof grommet having a first sealing member and a second sealing member. The first member has a first sealing part formed on the inner surface of a through-hole through which an electrical wire connected to a contact is passed. The first sealing part adheres tightly to the electrical wire. The second member has a second sealing part formed on the outer surface of the through-holes that adheres tightly to the connector housing. The first member is formed from an elastic material that has a lower hardness than that of the second member. As a result, splitting of the inner surface of the through-holes is prevented without causing any deterioration of the waterproof properties of the joint between the connector housing and the waterproof grommet.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way of example with reference to the accompanying figures wherein:
FIG.
1
(A) is a front view of the waterproof grommet,
FIG.
1
(B) is a bottom view of the waterproof grommet,
FIG.
1
(C) is a plan view of the waterproof grommet,
FIG.
1
(D) is a left-side view of the waterproof grommet,
FIG.
1
(E) is a back view of the waterproof grommet, and
FIG.
1
(F) is a sectional view along line
1
F—
1
F of FIG.
1
(A).
FIG.
2
(A) is a plan view of the waterproof grommet attached to the connector,
FIG.
2
(B) is a back view of the waterproof grommet attached to the connector,
FIG.
2
(C) is a front view of the waterproof grommet attached to the connector,
FIG.
2
(D) is a left-side view of the waterproof grommet attached to the connector, and
FIG.
2
(E) is a sectional view along line
2
E—
2
E of FIG.
2
(D).
FIG. 3
is an exploded perspective view of a method of assembly of the connector using the waterproof grommet.
FIG. 4
is a perspective view of a connector using a conventional waterproof grommet.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS.
1
(A)-(F), show a waterproof grommet
1
having a substantially rectangular body. The grommet
1
consists of a second member
30
that surrounds a first member
20
. The first member
20
is equipped with three through-holes
21
arranged in the shape of an inverted triangle. The through-holes pass through the entire length of the grommet
1
from the front surface to the back surface (the left-right plane in FIG.
1
(F)). A first sealing part
22
is disposed on the inner surface of each through-hole
21
. The first sealing part
22
has three annular ribs
22
a
that tightly adhere to the corresponding electrical wire. Three protruding parts
23
are used to align the grommet
1
with a connector housing
40
. The three protruding parts
23
align the recessed parts
43
that communicate with contact cavities
41
formed in the connector housing
40
. The three protruding parts
23
are formed so that the protruding parts
23
project from the front surface in positions corresponding to the respective through-holes
21
.
The second member
30
is equipped with a first-member accommodating part
34
that accommodates the first member
20
. The second member
30
has a second sealing part
32
with three annular ribs
32
a
on its outer circumferential surface. Three recessed parts
33
are formed on the back surface of the second member
30
and engage with protruding parts
62
formed on a waterproof grommet cap
60
. Insertion openings
31
having a tapered shape, are formed coaxially with the first member through-holes
21
and communicate with the through-holes
21
of the first member
20
. The second sealing part
32
is disposed so that it adheres tightly to the connector housing
40
.
The three recessed parts
33
with which the protruding parts
62
of the waterproof grommet cap
60
engage are formed so that the distances
33
a
between the recessed parts
33
and the outer circumferential surface are substantially the same (FIG.
1
(E)). The distances
33
b
between the recessed parts
33
and the insertion openings
31
are also substantially the same.
The first member
20
is formed from an elastic material that is softer than the material used to form the second member
30
. The first member
20
and the second member
30
are preferably formed from silicone rubbers that have different degrees of hardness. Here, a silicon rubber with a hardness of 10 is used for the first member
20
. A silicone rubber with a hardness of 50 is used for the second member
30
. The first
20
and second
30
members are formed as an integral unit by two-color molding.
The connector housing
40
has a tubular shape (FIG.
3
and FIG.
2
(E)). The housing
40
is equipped with three contact cavities
41
. Disposed on the back surfaces of the contact cavities
41
is an engaging part
42
used to engage the waterproof grommet
1
. Elastic lances
44
are formed inside the respective contact cavities
41
and anchor the contacts. A retainer
45
restricts the movement of the elastic lances
44
after the elastic lances
44
have anchored the contacts. The engaging part
42
has recessed parts
43
formed on the back surfaces of the contact cavities
41
used for alignment with the waterproof grommet
1
.
The waterproof grommet cap
60
is separate from the connector housing
40
(FIG.
2
(E) and FIG.
3
). The grommet cap
60
functions as a waterproof grommet supporting member and has a tubular shape which allows insertion and engagement from the front of the connector housing
40
on which the waterproof grommet
1
and sealing ring
50
are mounted. The grommet cap
60
has three protruding parts
62
that align the through-holes
21
of the grommet
1
and the contact cavities
41
by entering the recessed parts
33
of the waterproof grommet
1
.
Alternatively, the protruding parts
62
may be disposed on the front surface of the engaging part
42
of the connector housing
40
and used as waterproof grommet supporting members. In this case, the recessed parts
33
into which the protruding parts
62
are inserted are formed from the front surface of the second member
30
of the waterproof grommet
1
. The recessed parts
33
that engage with the protruding parts
62
are formed so that the distances
33
a
between the recessed parts
33
and the outer circumferential surface are substantially the same, and so that the distances
33
b
between the recessed parts
33
and the insertion openings
31
are substantially the same. Accordingly, the compression margin of the second member
30
in a state in which this member is mounted in the connector housing
40
and electrical wires are passed through is made uniform, so that the waterproof properties can be improved.
Three electrical wire through-holes
61
are formed in the grommet cap
60
corresponding to the through-holes
21
formed in the grommet
1
. Electrical wire, connected to contacts, passes through the through-holes
61
. The sealing ring
50
has a sealing part
52
that is equipped with three annular ribs
52
a
. The ribs
52
a
prevent the invasion of water through the gap present between the housing
40
and a mating connector (not shown).
Hereafter, the method used to manufacture the connector
1
A using the waterproof grommet
1
will be described (FIG.
2
).
First, the waterproof grommet
1
is inserted and engaged with the engaging part
42
from the rear of the connector housing
40
(FIG.
3
). A compressive force is applied to the waterproof grommet
1
in the X and Y directions (FIG.
1
(A)). The compressive force causes the protruding parts
23
to project from the front surface of the waterproof grommet
1
. The protruding parts
23
are inserted and engaged in the recessed parts
43
that are formed so that the recessed parts
43
communicate with the contact cavities
41
of the connector housing
40
(FIG.
3
). The annular ribs
32
a
of the second sealing part
32
formed on the outer circumferential surface of the waterproof grommet
1
are elastically pressed against the inner circumferential surface of the engaging part
42
of the connector housing
40
, preventing the invasion of water into the housing
40
.
The connector housing
40
is then passed through the central hole
51
of the sealing ring
50
from the rear side and mounted. The protruding parts
62
formed on the grommet cap
60
are inserted and engaged in the recessed parts
33
formed in the rear surface of the waterproof grommet
1
(FIG.
3
), aligning the contact cavities
41
with the through-holes
21
. In a case where the protruding parts
62
are disposed on the engaging part
42
of the connector housing
40
and used as waterproof grommet supporting members, the protruding parts
62
and recessed parts
33
formed in the front surface of the second member
30
are engaged when the waterproof grommet
1
is inserted and engaged in the engaging part
42
from the rear of the connector housing
40
.
Since the three recessed parts
33
are formed so that the distances
33
a
between the recessed parts
33
and the outer circumferential surface are substantially the same, the thicknesses between the recessed parts
33
and the outer circumferential surface are compressed by substantially the same amount. Because the compression margin of these thicknesses is made uniform, the waterproof properties of the joint between the connector housing
40
and waterproof grommet
1
are greatly improved.
Three electrical wires connected to contacts are then inserted via the electrical wire through-holes
61
formed in the rear surface of the grommet cap
60
. The contacts are inserted into the contact cavities
41
of the connector housing
40
. The annular ribs
22
a
of the first sealing parts
22
formed on the inner surfaces of the through-holes
21
of the waterproof grommet
1
are elastically pressed against the outer surfaces of the electrical wires. Since the three recessed parts
33
in the waterproof grommet
1
are formed so that the distances
33
b
between the recessed parts
33
and the insertion openings
31
are substantially the same, the thicknesses between the recessed parts
33
and the insertion openings
31
are compressed more or less uniformly. Thus, the compression margin of the thicknesses is made uniform. As a result, the waterproof properties of the joints between the electrical wires and the waterproof grommet
1
are greatly improved.
The shoulder parts (not shown) of the contacts are anchored by the elastic lances
44
formed in the connector housing
40
. The retainer
45
is positioned above the elastic lances
44
, anchoring the contacts in the connector housing
40
. The mating connector (not shown) is connected from the front of the connector housing
40
(the left direction in FIG.
2
(E)). Thus, invasion by water via the gap that exists between the connector housing
40
and the mating connector is prevented by the annular ribs
52
a
of the sealing part
52
of the sealing ring
50
.
While the present invention has been described in connection with the illustrated embodiments, it will be appreciated and understood that modifications may be made without departing from the true spirit and scope of the invention. For example, the number of through-holes, annular ribs, and recessed parts may be adjusted as required by alternative embodiments. Further, an array of elastic materials with varying degrees of hardness may be used to form the first and second members.
Claims
- 1. A waterproof grommet comprising:a first member having a first sealing part formed on the inner surface of at least one through-hole through which an electrical wire that connects a contact is passed, and which can adhere tightly to the electrical wire; a second member having a second sealing part which is formed on the outer circumferential surface of the through-hole, and which can adhere tightly to a connector housing; and the first and second member are formed from an elastic material, the elastic material of the first member having the first sealing part is formed from an elastic material that has a lower hardness than the elastic material of the second member having the second sealing part to prevent splitting on the inner surface of the through-hole when the electrical wire is passed therethrough.
- 2. The waterproof grommet of claim 1 wherein the second member has an insertion opening with a tapered shape and is disposed at the insertion entry point for the contact in the through-hole.
- 3. The waterproof grommet of claim 2 wherein the first member and the second member are formed as an integral unit by two-color molding.
- 4. The waterproof grommet of claim 1 wherein the first member and the second member are formed as an integral unit by two-color molding.
- 5. The waterproof grommet of claim 1 wherein the second member has recessed parts used to align a contact cavity formed in the connector housing with the through-hole by engaging with protruding parts formed on a waterproof grommet supporting member; andthe recessed parts are formed so that the distances between the recessed parts and the outer circumferential surface are substantially the same, and so that the distances between the recessed parts and the through-holes are substantially the same.
- 6. The waterproof grommet of claim 5 wherein the waterproof grommet supporting member is a waterproof grommet cap that is separate from the connector housing.
- 7. The waterproof grommet of claim 1, wherein the first and second members are made from silicone rubber.
- 8. The waterproof grommet of claim 7, wherein the silicone rubber of the first member has a hardness of approximately 10 and the silicone rubber of the second member has a hardness of approximately 50.
- 9. The waterproof grommet of claim 1, wherein the first sealing part and the second sealing part include ribs.
- 10. The waterproof grommet of claim 1, wherein the second member has at least one recessed part which is used to align a contact cavity formed in the connector housing with the through-hole by engaging with at least one protruding part formed on a supporting member.
- 11. The waterproof grommet of claim 1, wherein the second member has at least one recessed part that engages a protruding part formed on the connector housing so that the second member has a uniform compression margin when the electrical wire is received in the through-hole.
- 12. The waterproof grommet of claim 11, wherein the recessed parts are formed: so that the distance between the recessed parts and the outer circumferential surface are essentially the same and so that the distances between the recessed parts and the through-hole are substantially the same.
- 13. A waterproof grommet comprising:a first member having a first sealing part formed on the inner surface of at least one through-hole through which an electrical wire that connects to a contact is passed, the first sealing part being formed to adhere tightly to the electrical wire; a second member having a second sealing part formed on the outer circumferential surface of the through-hole, the second sealing part being formed to adhere tightly to a connector housing; the first member having the first sealing part is formed from an elastic material that has a lower hardness than the hardness of the second member having the second sealing part; the first member and the second member are formed as an integral unit by two-color molding; the second member has at least one recessed part which is used to align a contact cavity formed in the connector housing with the through-hole by engaging with at least one protruding part formed on a waterproof grommet supporting member; and the recessed part(s) are formed so that the distances between the recessed part(s) and the outer circumferential surface of the through-hole(s) are substantially the same, and so that the distances between the recessed part(s) and the through-hole(s) are substantially the same.
- 14. The waterproof grommet of claim 13 wherein the waterproof grommet supporting member is a waterproof grommet cap that is separate from the connector housing.
- 15. A waterproof grommet comprising:a first member having a first sealing part formed on the inner surface of at least one through-hole through which an electrical wire that connects to a contact is passed, the first sealing part being formed to adhere tightly to the electrical wire; a second member having a second sealing part formed on the outer circumferential surface of the through-hole, the second sealing part being formed to adhere tightly to a connector housing; the first member having the first sealing part formed from an elastic material that has a lower hardness than the hardness of the second member having the second sealing part; the second member having an insertion opening with a tapered shape and disposed at the insertion entry point for the contact in the through-hole, and has at least one recessed part which is used to align a contact cavity formed in the connector housing with the through-hole by engaging with at least one protruding part formed on a waterproof grommet supporting member; and the recessed part(s) are formed so that the distances between the recessed part(s) and the outer circumferential surface of the through-hole(s) are substantially the same, and so that the distances between the recessed part(s) and the through-hole(s) are substantially the same.
- 16. The waterproof grommet of claim 15 wherein the first member and the second member are formed as an integral unit by two-color molding.
- 17. The waterproof grommet of claim 16 wherein the waterproof grommet supporting member is a waterproof grommet cap that is separate from the connector housing.
- 18. The waterproof grommet of claim 15 wherein the waterproof grommet supporting member is a waterproof grommet cap that is separate from the connector housing.
- 19. A waterproof grommet assembly, comprising:a first member having a first sealing part formed on an inner surface of a through-hole that sealingly engages an electrical wire received in the through-hole; a second member having a recessed part for receipt of a protrusion formed on a supporting member and a second sealing part formed on an outer circumferential surface of the through-hole that sealingly engages a housing.
- 20. The waterproof grommet assembly of claim 19, wherein the supporting member is an engaging part on the housing.
- 21. The waterproof grommet assembly of claim 19, wherein the supporting member is a waterproof grommet cap that is separate from the housing.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-307509 |
Oct 2000 |
JP |
|
US Referenced Citations (5)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0 738 025 |
Oct 1996 |
EP |