Electrical connectors – With external conductor or cable embedded in insulative...
Reexamination Certificate
2000-04-20
2001-07-03
Sircus, Brian (Department: 2839)
Electrical connectors
With external conductor or cable embedded in insulative...
C439S936000
Reexamination Certificate
active
06254432
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sealing structure in a sensor having lead wires such as a brake fluid (oil) level sensor in a vehicle, and more particularly to the sealing structure in which a filling material for the seal is prevented from intruding into a spacing between the lead wires.
2. Description of the Related Art
FIG. 3
shows a sealing structure in a conventional sensor having lead wires. This structure consists of a case
1
formed of a synthetic resin, a reed switch
2
contained in the case
1
and provided with lead wires
3
,
4
, a rubber plug
19
provided outside the lead wires
3
,
4
and fitted to an inner peripheral wall
6
a
of the case
1
, and a resin material
9
filled in an opening
8
of the case
1
above the rubber plug
19
in order to hold the lead wires
3
,
4
and seal the reed switch
2
.
The reed switch
2
contains therein a pair of magnetic reeds (not shown) whose contact portions are brought into contact by magnetization, and generally employed as a fluid level sensor for a brake or clutch in a vehicle. The sensor
18
having the lead wires is disposed in such a manner that the reed switch
2
faces with a magnetic area in a float (not shown) in an operating fluid such as the brake fluid.
A pair of lead terminals
16
,
17
of the reed switch
2
are connected by soldering to conductive terminals
3
a,
4
a
of the lead wires
3
,
4
respectively. A pair of the lead wires
3
,
4
are passed through bores
13
(
FIG. 4
) in the rubber plug
19
and guided out of the opening
8
of the case
1
to the connector
11
. The connector
11
is composed of a housing
20
formed of a synthetic resin and terminals (not shown) contained in the housing
20
. To the terminals are pressure welded distal ends of the lead wires
3
,
4
.
The case
1
is formed in an oblong shape in cross section, including a bottom portion
14
at one end and the opening
8
at the other end in a longitudinal direction. The opening
8
is enlarged in diameter in a tapered shape. The rubber plug
19
is inserted into the case
1
to be fitted to the inner peripheral face
6
a
of a cylindrical wall
6
which is straight and continues from the tapered part
8
a.
As shown in
FIG. 4
, at an outer periphery of the rubber plug
19
are formed a plurality of lip portions
12
for tight fitting to the inner peripheral face
6
a
of the case
1
. The bores
13
in the rubber plug
19
are provided slightly apart from each other in a lateral direction so as to correspond to a space between a pair of the lead wires
3
,
4
. The inner peripheries of the bores
13
are also provided with lip portions (not shown), which are adapted to be tightly fitted to the outer peripheral faces of the lead wires
3
,
4
.
In
FIG. 3
, the resin material
9
is filled between an upper end face
19
a
of the rubber plug
19
and an inlet
8
b
of the opening
8
of the case
1
. The opening
8
covers herein a rather wide area including the inlet
8
b
and the tapered part
8
a
which is enlarged in diameter. The resin material
9
which is an epoxy resin or the like will be hardened after poured thereby to hold the lead wires
3
,
4
in the case
1
, and at the same time, to seal the reed switch
2
and the lead wires
3
,
4
inside the case
1
. The case
1
, the reed switch
2
, the lead wires
3
,
4
, the rubber plug
19
and the resin material
9
constitute the sensor
18
having the lead wires which is the brake fluid level sensor.
The brake fluid level sensor
18
is fixed to a bottom wall of a brake master cylinder (not shown) in the vehicle and may be disposed in the brake fluid, for example. In this case, the rubber plug
19
and the resin material
9
will prevent the brake fluid from intruding into the case
1
. In case that the brake fluid level sensor is disposed outside the brake master cylinder, the rubber plug
19
and the resin material
9
will serve for waterproofing or dustproofing purposes.
However, in the above described conventional structure, there has been a problem that when the resin material
9
is poured into the opening
8
of the case
1
, the resin material
9
will enter into and rise along a narrow spacing
21
between the lead wires
3
,
4
by a capillary phenomenon, as shown in
FIG. 3
in an enlarged scale. The resin material
9
thus hardened in this state will create a sharp projection
22
between the lead wires
3
,
4
, which may damage the coverings on the lead wires
3
,
4
when the lead wires
3
,
4
are bent at an end face
9
a
of the resin material
9
. This problem may be the same in such a case that a hard rubber material is employed instead of the resin material
9
. Particularly, in case where a bending force is applied to the lead wires
3
,
4
in filling the resin material
9
, the lead wires
3
,
4
will be hardened as they are bent and create gaps in the resin material
9
, resulting in poor sealing property and deterioration in quality of the products.
BRIEF SUMMARY OF THE INVENTION
In view of the above described problems, the object of the present invention is to provide a sealing structure for a sensor having lead wires in which a filling material will not rise along a spacing between lead wires when the filling material such as resin is poured into an opening of a case from which a plurality of the lead wires are guided out, and accordingly, damages of the lead wires will be avoided and the lead wires can be held at normal positions even in case where a bending force is applied to the lead wires when filling the resin material.
In order to attain the above described object, there is provided according to the present invention, a sealing structure for a sensor having lead wires which comprises an electric element provided with a plurality of the lead wires and contained in a case, a rubber plug inserted into an opening of the case, the lead wires being guided out of the rubber plug through respective bores formed therein, and a filling material filled in the opening above the rubber plug, the rubber plug being provided with a partition wall for providing a space between the lead wires, and the partition wall being disposed in the filling material, whereby the lead wires are spaced from each other by the partition wall.
According to another aspect of the invention, a top end of the partition wall reaches a level of a surface of the filling material.
According to a further aspect of the invention, lateral faces of the partition wall are in alignment with extension lines of inner faces of the bores.
According to a still further aspect of the invention, the partition wall is formed of the same material as the rubber plug integrally therewith.
According to a still further aspect of the invention the partition wall is formed of a resin material different from the rubber plug.
Now, a preferred embodiment according to the invention will be described by way of examples referring to the drawings.
REFERENCES:
patent: 3457441 (1969-07-01), Phillips et al.
patent: 4083902 (1978-04-01), Clyde
patent: 4454381 (1984-06-01), Ito et al.
patent: 5561273 (1996-10-01), Yamanashi
patent: 5603627 (1997-02-01), Evanisko
patent: 5637007 (1997-06-01), Suzuki et al.
Armstrong Westerman Hattori McLeland & Naughton LLP
Nguyen Son V.
Sircus Brian
Yazaki -Corporation
LandOfFree
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