JP2003036732A - Flexible flat cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new flexible flat cable that has an increased current- carrying capacity under a permissible temperature range of a material by improving dissipation of heat. SOLUTION: On each side of a flexible base film 6, a plurality of flat parallelepiped conductors 2, 2... are positioned so as to be staggered viewed from its cross section at fixed intervals, the each flat parallelepiped conductor 2 laminated with a belt-like plastic film 3 having an adhesive to be integrated with the base film 6 so that each parallelepiped conductor 2 may be independent of adjacent ones. Accordingly, because the heat generated in a live wire is dissipated effectively with the surface area increase, the current-carrying capacity under the permissible temperature range of the material is increased largely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible flat cable (FFC) which is widely used as a wiring material for movable parts of various electric and electronic devices.

[0002]

2. Description of the Related Art As shown in FIG. 10, in a conventional flexible flat cable a, a plurality of conductors b having a rectangular cross section are arranged in parallel and laminated with a pair of plastic films c and c with an adhesive from above and below. It is an integrated band-shaped electric wire.

Since such a flexible flat cable a generally has excellent flexibility and bending resistance, and has characteristics such as light weight and high mounting density,
In particular, it is widely used as a wiring material for communication and movable parts of various small electric and electronic devices such as office automation equipment such as personal computers and printers, audio equipment such as CD players, etc., and in the future, not only communication cables, A wide range of applications are being considered as cables for energizing automobile electric parts and the like.

[0004]

By the way, when a plurality of such flexible flat cables a are applied as a conventional communication cable to a current-carrying cable, a countermeasure against heat generation during power-on becomes a problem.

That is, for example, when the flexible flat cable a is applied as a cable for energizing a movable part of an automobile airbag, it is necessary to secure an allowable current value of a maximum of several amperes. In the case of the cable a, since the heat dissipation property in the middle is particularly poor, the amount of energizing current within the allowable temperature of the material is low, and it is difficult to apply it as it is.

Therefore, for example, it is conceivable to suppress the heat generation by increasing the diameter of the conductor and reducing the conductor resistance. However, if this is done, the weight of the entire cable increases and the bending resistance deteriorates, so that it is lightweight and As a result, the original characteristics of the flexible flat cable, such as bending resistance, are greatly impaired.

Therefore, the present invention has been devised to effectively solve such a problem, and an object thereof is to improve heat dissipation and increase the current capacity within the allowable temperature of the material. A new flexible flat cable that can be used is provided.

[0008]

In order to solve the above-mentioned problems, the present invention provides a plurality of rectangular conductors on both sides of a flexible base film at regular intervals in a zigzag cross section, and Each flat conductor is laminated with a strip-shaped adhesive-attached plastic film so as to be independent of the adjacent flat conductor, and is integrated with the base film side.

As a result, the surface area increases and the contact area with air increases, so that the heat generated during energization is effectively dissipated, and the amount of energizing current within the allowable temperature of the material can be greatly increased.

As a result, it becomes possible to apply the flexible flat cable as a current-carrying cable without significantly impairing the original characteristics of the flexible flat cable such as light weight and high packaging density.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment for carrying out the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view showing an embodiment of a flexible flat cable 1 (hereinafter referred to as FFC1) according to the present invention, FIG. 2 is an enlarged sectional view taken along the line AA in FIG. 1, and FIG. It is a middle BB line expanded sectional view.

As shown in the figure, the FFC 1 includes a main body portion 4 in which a plurality of rectangular conductors 2, 2 ... Are covered with strip-shaped adhesive-attached plastic films 3, 3 ,. , And conductors 2, 2 ... consist of exposed end portions 5 and 5, which are connected to connectors (not shown) of electronic / electrical circuits to which the end portions 5 and 5 are applied, respectively. The section 4 energizes between the electronic and electric circuits.

As shown in FIG. 2, the main body portion 4 has a plurality of rectangular conductors 2, 2 ... Arranged on both sides of a flexible base film 6 in a zigzag pattern at regular intervals. The flat conductors 2 are laminated with a strip-shaped adhesive-attached plastic film 3 so as to be independent of the adjacent flat conductors 2 and integrated with the base film 6 side. That is, the main body 4 has a structure in which every other FFC rectangular conductor having a conventional structure is vertically shifted for each adhesive-attached plastic film 3.

On the other hand, in the terminal portion 5, as shown in FIG. 3, the flat conductors 2 are held on the reinforcing plate 7 with the adhesive-attached plastic film 3 interposed therebetween while the upper surfaces of the flat conductors 2 and 2 are exposed. The structure is as follows.

In the FFC 1 of this embodiment having such a structure, the conductors 2, 2 ...
Are arranged independently on the upper and lower surfaces of the base film 6 in a zigzag cross section, as shown in FIG.
Since the surface area is larger than that of the conventional structure and the contact area with the air is increased, the heat generated in each of the conductors 2, 2, ... By energization is effectively dissipated. As a result, the current capacity within the allowable temperature of the material around the conductor 2, that is, the plastic film with adhesive 3 can be significantly increased. Moreover, since the sizes of the conductors 2, 2 ... Are the same as the conventional ones, the FFC's original characteristics such as light weight and bending resistance are not significantly impaired.

Next, FIGS. 4 to 8 show another embodiment of the present invention.

First, FIG. 4 shows a reinforcing plastic sheet 8 interposed between the upper and lower conductor groups 2, 2.
That is, in the case of the embodiment of FIG.
Since the structure is such that the connection is made only by the very thin base film 6, it is possible that when some force is applied, the base film 6 is torn and broken at the boundary portion. By using the reinforcing plastic sheet 8 having an appropriate strength as described above, it is possible to effectively avoid such an inconvenience.

Further, as shown in FIG. 5, if a metal sheet 9 having an appropriate flexibility is used instead of the plastic sheet 8, it becomes possible to promote a heat dissipation effect in addition to the above effects. .

On the other hand, as another embodiment of the terminal section 5,
As shown in FIG. 6, a structure may be adopted in which the conductor ends are fixed as they are above and below the reinforcing plate 7.

Further, in each of the above embodiments, each conductor 2,
Although the surface areas are increased by arranging 2 ... in a zigzag cross section, as shown in FIGS. 7 and 8, the conventional structure F is used.
By forming the slits 10, 10 ... Which extend in the longitudinal direction between the conductors 2 and 2 with respect to the FC, the surface area of the entire FFC increases, and the same effect as in the above-described embodiment can be obtained. In the present embodiment, the slit 1
It is desirable to further provide a metal sheet 9 or the like on the lower surface or the upper surface side so that the conductors 2, 2 ... Are not separated by forming 0.

[0022]

EXAMPLE As an example of the present invention, a rectangular conductor having a cross-sectional area of 0.08 mm ² is used and arranged in a zigzag manner as shown in FIG.
After manufacturing, 10 sheets were bundled and energized, and a test was performed to evaluate the energized current and the temperature rise characteristics.

The test conditions are as follows: ambient temperature: 3
0 ° C, energization method: All poles (series connection), energized with a predetermined current (0.5A, 1.0A) for a predetermined time, and at that time, the temperature of the center of the 6th conductor of the 10th FFC The rise was measured by a thermocouple.

Comparative Example As a comparative example of the present invention, ten conventional FFCs were used, and a test was conducted to evaluate the energizing current and temperature rise characteristics under the same conditions as in the examples.

As a result, as shown in FIG. 9, in the conventional FFC, the temperature rises remarkably, and the maximum temperature is about 78 ° C. when 1 A is energized, and 50 ° C. even when 0.5 A is energized. The conductor temperature has risen to near.

On the other hand, in the FFC of the present invention,
The temperature rise is slower than the conventional specification, the maximum temperature when 1A is energized, or about 5 ° C lower than the conventional specification.
Even when energized at 0.5 A, it is always about 2 ° C more than the conventional specifications.
It turned out to be low.

Therefore, as can be seen from this embodiment,
By adopting the structure of the present invention, it is possible to effectively suppress the temperature rise of the conductor, and it is possible to significantly increase the current capacity in the allowable temperature range of the material as compared with the conventional case.

[0028]

In summary, according to the present invention, since the surface area is increased and the heat dissipation property is improved, the rise in the conductor temperature can be effectively suppressed. As a result, it is possible to increase the current capacity within the allowable temperature of the material, and thus it is possible to apply not only as a communication cable but also as a high-current energizing cable.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of an FFC according to the present invention.

FIG. 2 is an enlarged sectional view taken along line AA in FIG.

FIG. 3 is an enlarged sectional view taken along line BB in FIG.

FIG. 4 is an enlarged cross-sectional view showing another embodiment of the main body part of the FFC according to the present invention.

FIG. 5 is an enlarged cross-sectional view showing another embodiment of the main body of the flexible flat cable according to the present invention.

FIG. 6 is an enlarged cross-sectional view showing another embodiment of the terminal portion of the FFC according to the present invention.

FIG. 7 is a plan view showing another embodiment of the FFC according to the present invention.

8 is an enlarged cross-sectional view taken along the line AA in FIG.

FIG. 9 is a graph showing a current-carrying current and a conductor temperature characteristic according to the present embodiment.

FIG. 10 is an enlarged cross-sectional view showing an FFC having a conventional structure.

[Explanation of symbols]

1 Flexible flat cable (FFC) 2 flat conductor 3 Plastic film with adhesive 4 main body 5 Terminal 6 base film 7 Reinforcement plate 8 plastic sheets 9 metal sheets 10 slits

Claims (3)

[Claims] 1. A plurality of flat conductors are arranged on both sides of a flexible base film in a zigzag cross section at regular intervals, and each flat conductor is strip-shaped so as to be independent of an adjacent flat conductor. A flexible flat cable characterized by being laminated with a plastic film with an adhesive and integrated with the base film side. 2. A plurality of flat conductors are arranged on both sides of a plastic or metal film in a zigzag cross section at regular intervals, and a pair of flat conductors are provided so as to be independent of adjacent flat conductors. A flexible flat cable characterized by being laminated with a band-shaped plastic film with an adhesive and integrated with the base film side. 3. A plurality of rectangular conductors arranged in parallel at regular intervals are laminated with a pair of plastic films with an adhesive to be integrated and provided on a flexible base film. A flexible flat cable having a slit extending in the longitudinal direction therebetween.