Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
1998-10-02
2001-02-06
Kincaid, Kristine (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
C439S098000
Reexamination Certificate
active
06184471
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a connecting structure and method for a shielded cable.
The shielded cable comprises conductive core wires, an inner insulating cover for covering an outer periphery of the core wires, a braided wire on an outer periphery of the inner insulating cover and an outer insulating cover for covering an outer periphery of the inner insulating cover over the braided wire. According to a conventional connecting structure of the shielded cable, the shielded cable is separated to the core wires and braided wire at an end portion thereof, then, an end of the braided wire is bound with a heat shrinkage tube and the ends of the core wires and braided wire are crimped with a terminal metal (Japanese Patent Application Laid-Open Publication No. 201383).
However, the aforementioned conventional structure requires a step for peeling the outer insulating cover to expose the braided wire, for peeling the inner insulating cover to expose the core wires, for twisting the exposed braided wire and for inserting the twisted braided wire into a heat shrinkage tube. Therefore, the connecting procedure is complicated.
Further, because there exists no braided wire on a long distance of the inner insulating cover, there is a possibility that the shielding performance may drop.
Therefore, an object of the present invention is to provide a connecting structure having a simple structure, capable of keeping an excellent shielding performance, not requiring a troublesome cover peeling procedure, and enabling to carry out a connecting work rapidly and easily, and a method therefor.
SUMMARY OF THE INVENTION
To achieve the above object, according to a first aspect of the present invention, there is provided a connecting structure for connecting a shielded cable and a terminal, comprising: a shielded cable having conductive core wire, an inner insulating portion for covering the core wire, a braided wire on an outer periphery of the inner insulating portion, and an outer insulating portion over the braided wire for covering the outer periphery of the inner insulating portion; and a terminal containing a connecting portion coated with melt-joining material, the melt-joining material facing the braided wire with the connecting portion being inserted in the shielded cable, and the shielded cable subjected to ultrasonic vibration through small protrusions of an ultrasonic horn on the outer insulating portion, whereby the melt-joining material is melted so as to conductively connect the braided wire and the connecting portion with each other.
The aforementioned melt-joining material may be solder.
The connecting portion of the terminal has only to be inserted into the shielded cable such that it opposes the braided wire. Concretely, the connecting portion may be inserted in between the outer insulating portion and braided wire or between the braided wire and inner insulating portion.
An ultrasonic horn for use in the connecting structure of the present invention has a plurality of small protrusions on an end portion thereof. Each of the small protrusions comes into contact with an outer periphery of the outer insulating cover. If the ultrasonic horn vibrates ultrasonically, each small protrusion transmits ultrasonic vibration to the shielded cable. By this transmission, the melt-joining material is melted so that the braided wire of the shielded cable and connecting portion of the terminal are conductively connected with each other.
In the above described structure, the braided wire and terminal are not mechanically in contact with each other, but metallically connected with each other by melting and joining of the melt-joining material. Thus, a high reliability is obtained in terms of electrical connection.
A cover peeling procedure for exposing the braided wire is not required. Thus, the braided wire and terminal can be connected with each other easily thereby reducing the number of steps of the procedure.
Because the braided wire covers almost all area of the inner insulating cover, the shielding performance is maintained in an excellent condition.
All surface of an end portion of the ultrasonic horn is not in contact with the shielded cable, but only the small protrusions are in contact therewith, so that ultrasonic energy is applied to the shielded cable through the small protrusions in contact. Thus, ultrasonic energy acts concentratedly. As a result, energy loss is extinguished and the joining material is melted sufficiently even in a short time or with a small output. Consequently, the outer insulating portion can be prevented from being damaged by ultrasonic vibration.
The ultrasonic energy is applied to the shielded cable through each of the plural small protrusions. Therefore, as compared to a case in which an ultrasonic horn having a flat shaped end portion is used, ultrasonic energy is applied equally in a predetermined range. That is, ultrasonic energy is applied equally to all surface of the connecting portion of the terminal. Thus, there never an event in which the joining material coated on the connecting portion is dispersed in uneven directions. As a result, the braided wire and connecting portion are evenly joined with each other at a contact portion therebetween thereby a reliable connecting strength being obtained.
According to a second aspect of the present invention, there is provided a connecting structure according to the first aspect, wherein the connecting portion of the terminal is inserted between the braided wire and the inner insulating portion.
According to the above structure, as compared to a case in which the connecting portion is inserted in between the outer insulating portion and braided wire, it is inserted deeply in the diameter direction of the shielded cable. Therefore, the terminal and shielded cable are firmly connected with each other and even if a pulling force is applied to the terminal, the terminal never slips out, so that a stable connection is maintained.
According to a third aspect of the present invention, there is provided a connecting structure according to the first aspect, wherein the terminal includes a sheet-like terminal main body, the connecting portion on one side of the terminal main body, and a grounding terminal portion on the other side of the terminal main body, and the melt-joining material is coated on a surface of the connecting portion.
In the above structure, the terminal main body comprises only the connecting portion and grounding terminal portion. The connecting portion is inserted into the shielded cable so that the terminal is connected. Therefore, the terminal does not have to be formed in a complicated shape for engaging with or joining with the shielded cable. Thus, the terminal has a simple structure, so that production and handling thereof are easy.
According to a fourth aspect of the present invention, there is provided a connecting method for connecting a shielded cable and a terminal, the shielded cable comprising conductive core wire, an inner insulating portion for covering the core wire, a braided wire on an outer periphery of the inner insulating portion, and an outer insulating portion over the braided wire for covering the outer periphery of the inner insulating portion, and the terminal containing a connecting portion coated with melt-joining material, the method comprising the steps of:
inserting the connecting portion into the shielded cable, the melt-joining material facing the braided wire, while a slit is formed on the outer insulating portion and the connecting portion is inserted into the shielded cable through the slit; and
applying ultrasonic vibration to the shielded cable through small protrusions of an ultrasonic horn in contact with the outer insulating portion, the melt-joining material being melted so as to conductively connect the braided wire and the connecting portion with each other.
Because the connecting portion of the shielded terminal is inserted through the slit formed on the outer insulating portion of the shielded cable, the work for inserting the c
Asakura Nobuyuki
Ide Tetsuro
Kuwayama Yasumichi
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kincaid Kristine
Nguyen Chau N.
Yazaki -Corporation
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