Waterproof structure for terminal

Details Waterproof structure for terminal Waterproof structure for terminal

2002-06-17

2004-01-13

Nguyen, Chau N. (Department: 2831)

Electricity: conductors and insulators

Conduits, cables or conductors

Combined

C174S092000

Reexamination Certificate

active

06677531

ABSTRACT:

The present application is based on Japanese Patent Application NO. 2001-182820, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates to a waterproof structure for a terminal, which is enabled to prevent infiltration of water and oil into a conductor from a crimping part, which crimps a terminal metal fitting thereonto, at a terminal part of electric wires or cables (hereinafter referring to merely “wire”) to thereby maintain insulation performance.
Generally, a terminal metal fitting is crimped onto a conductor, such as a stranded copper round wire exposed by peeling a coating, at a terminal part of each electric wire by caulking. Such a conductor is connected to an input/output terminal of electric equipment, for example, a motor mounted on an electric car through this terminal metal fitting to thereby perform electrical conduction of the equipment.
Especially, in the case of a vehicle traveling outdoors, there has been a drawback in that infiltration of water contents, such as carwash water, rain water, and muddy water, and various kinds of oil contents, such as lubricating oil and rust prevention oil, into a conductor of a part of a terminal of an electric wire arranged on a vehicle body degrades the insulation performance.
A conventional terminal proposed so as to solve such a problem of infiltration of oily water into the conductor is for example, a waterproof-type wire terminal shown in FIG.
4
and described in JP-A-8-140253. An insulating coating
2
of a terminal of a wire
1
is peeled off, so that a conductor
3
constituted by a stranded copper round wire is exposed, and that the exposed conductor
3
is connected to a conductor connecting part
5
, which serves as an end part of a cylindrical terminal metal fitting
4
, by being fitted thereto. Further, the other end part of the terminal metal fitting
4
is crushed flat as a terminal connecting part
6
by press-working. Simultaneously, two bolt holes
7
are provided in the terminal connecting part
6
by stamping.
In this wire terminal connecting structure, to prevent water contents and oil contents from infiltrating an inlet of a part, at which the conductor
3
is inserted and fitted into the conductor connecting portion
5
of the terminal metal fitting
4
, a sealant
8
, such as hotmelt, is applied onto the entire joint of a connection in such a way as to extend to the insulating coating
2
of an end part of the wire
1
, and to thereby ensure sealing ability.
However, this conventional structure shown in
FIG. 4
has the following problems.
One is that variation in the amount of an applied sealer and application unevenness thereof are apt to occur, because of the manual application of the sealer
8
, and that reliable sealing cannot be ensured. Therefore, strict care should be paid to application management. Thus, the working cost thereof surges, while the production efficiency lowers.
Another is that when an external force, such as a bending force and a tensional force, are exerted on the wire
1
, a crack and a peel-off occurs in the applied sealer
8
, so that the sealing ability is impaired.
SUMMARY OF THE INVENTION
An object of the invention is to provide a waterproof structure for a terminal, which is enabled to prevent water contents and oil contents from infiltrating into a connecting part, in which a terminal metal fitting is crimped onto a terminal of an electric wire by caulking, and also prevent degradation in the insulation performance to thereby ensure desired sealing ability, and which is also enabled to simply and efficiently perform a sealing operation.
To achieve the foregoing object, according to the invention, there is provided a waterproof structure for a terminal (hereunder referred to a first structure of the invention), in which a terminal metal fitting
20
is crimped and connected to a conductor
11
exposed by performing a peeling operation on a terminal part of an electric wire
10
, and in which this connecting part of the conductor is covered with an elastic member (corresponding to a cap seal)
30
that is intimately contacted with the connecting part from the outside to thereby ensure sealing ability, and in which the elastic member is covered with and held by a protecting member (corresponding to a cap holder)
40
in such a way as to compress the elastic member
30
.
With the aforesaid configuration, the connecting part, at which the terminal metal fitting
20
is crimped onto the exposed conductor
11
, is intimately contacted with the elastic member
30
in such a way as not to be exposed to the outside. Thus, the conductor
11
of the crimped part is sealed in such a manner as to prevent insulation performance from being degraded by infiltration of water contents and oil contents into a connecting part and permeation of the water contents and the oil contents among the wires, which respectively include the conductors
11
. Further, such an elastic member
30
is accommodated and held in the protecting member
40
during a compressed condition thereof. Thus, the degree of intimate contact of the elastic member
30
with the connecting part is still more enhanced, and the reliability of sealing is still more improved. Furthermore, an operation of covering the connecting part with the elastic member
30
, and an operation of accommodating and holding this elastic member
30
in the protecting member
40
can be achieved in a short time by almost one touch. As compared with a conventional operation of ensuring the sealing ability by applying hotmelt, the efficiency in sealing is still more increased. Consequently, the reliability in sealing is still more improved.
Further, according to the first structure of the invention, the elastic member
30
is a rubber barrel, which is intimately contacted with and has a length being equal to that of the entire connecting part extending from an outer peripheral surface of the terminal part of the electric wire
10
, on which the peeling operation has been performed, to an outer peripheral surface of a partitioning wall part
23
.
According to this configuration, the elastic member
30
is made of rubber. Thus, even when an external force due to the bend and warpage of the electric wire
10
is exerted onto the crimping part between the conductor
11
and the terminal metal fitting
20
after the connection therebetween, the elastic member
30
elastically expands and contracts flexibly in response to the external force. Thus, the degree of intimate contact can be maintained. Moreover, the drawbacks of the conventional structure, such as an occurrence of a peel-off of the sealing part, onto which hotmelt is applied, can be solved.
Furthermore, the protecting member
40
is shaped like a cap, in which the elastic member
30
having been in a compressed condition is detachably accommodated.
With this configuration, the elastic member
30
is accommodated and held in the cap-shaped protecting member
40
during compressed. Thus, the invention is effective in increasing the degree of intimate contact of the elastic member
30
still more by compression.


REFERENCES:
patent: 3542276 (1970-11-01), James
patent: 4612680 (1986-09-01), Daiguji
patent: 4707566 (1987-11-01), Titcombe et al.
patent: 5229543 (1993-07-01), Strefling
patent: 5440073 (1995-08-01), Lin et al.
patent: 8-140253 (1996-05-01), None

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