JPH0356967Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a flat cable of a type in which a plurality of conductors arranged at intervals are sandwiched between thermoplastic resin films. This type of flat cable is used for connecting electronic devices that are becoming increasingly sophisticated in recent years, and there has been a trend toward higher transmission speeds and higher densities.

[Conventional technology]

For example, as a flat cable that holds multiple conductors spaced between resin films,
The one described in Publication No. -48513 has been proposed.
In this way, tape-laminated flat cables sandwich the conductor by placing the tape or film along the conductor and joining the insulating film with adhesive or heat fusion. A void with a triangular cross section is formed between the film and the film, which may cause insulation failure.

In particular, the pitch between conductor centers is 1.27 mm or 0.635
For this type of flat cable of about mm,
This type of void having a triangular cross section at both ends of the conductor was often the cause of poor insulation.

[Problem that the invention attempts to solve]

Therefore, the purpose of this invention is to solve the above-mentioned conventional problems and provide a flat cable with a structure in which the insulating layer is tightly adhered to the outer periphery of the conductor without any gaps between the insulating layer and the conductor. do.

[Means for solving problems]

Therefore, according to this invention, the insulating layer is made of a plurality of conductors placed in parallel and spaced apart, and an insulating layer made of a thermoplastic resin film that sandwiches the plurality of conductors. The flat cable includes an original shape maintaining part that substantially maintains the shape of the cable, and a thin part having a substantially concave arc shape that is press-molded in the direction of the conductor as well as in the thickness direction adjacent to the conductor position.

[Effect]

The insulating layer adjacent to the conductor position is press-molded into a thin, almost concave arc-shaped part, and is deformed by the force in the conductor direction at this time to fill the void, so each conductor is closely held by the insulating layer. sealed. As a result, there is no air space adjacent to the conductor, and the formation of conductive paths or semi-conductive paths due to airborne substances or conductive substances that enter from the cable terminals is eliminated.

Furthermore, since there is no space adjacent to the conductor, the area of the film in close contact with the conductor is increased, and peeling of the side edge insulating layer due to external stress such as vibration or deformation is eliminated.

Furthermore, since the insulating layer is pressure-molded between the conductors, each conductor is reliably placed in a predetermined position, and the accuracy of the conductor position is increased. In addition, the insulating layer at the conductor position can be made into a parallel part that maintains its original shape, and the contact area is increased at the connection terminal part, so it is better seated in the connector and the external force applied to the cable is absorbed by the insulating layer with a wide area. Since the structure supports the conductor, stress concentration on the conductor can be avoided.
Connection failures due to vibration, corrosion, disconnection, etc. will no longer occur.

〔Example〕

FIG. 1 is a partial cross-sectional view of a flat cable according to this invention.

This flat cable 1 has a plurality of conductors 2 arranged at equal intervals, sandwiched between two insulating layers 3 made of upper and lower thermoplastic resin films. An original shape maintaining part 4 that maintains the original resin film thickness over a certain width, and a substantially concave circle that is press-molded in the thickness direction and the conductor direction so that the original resin film thickness is thinner than the original resin film thickness adjacent to the original resin film thickness over a certain width. Arc-shaped thin-walled portions 5 are formed alternately.

Here, the conductor 2 is, for example, AWG (American wire gauge) 30 (diameter 0.254 mm) with a pitch between the conductors.
Used in parallel with a distance of 0.635 mm, in this case the insulating layer 3
For example, a tetrafluoroethylene resin film with a thickness of 0.25 mm is used. The insulating layer 3, which sandwiches the aligned conductors 2 from both sides, is provided with protrusions having a substantially arcuate cross-section over the circumference from both sides, and is heat-pressed by heat rolls arranged at a plurality of predetermined positions. As a result, a concave arc-shaped thin portion 5 is formed at a position between the conductors 2. In this process, the insulating layer 3 is softened and deformed, becomes thinner, and is pushed away to come into close contact with the outer periphery of each conductor 2, so that no void is formed near the conductor 2. At this time, both insulating layers 3 can be bonded by heat fusion, adhesion, or the like.

According to the flat cable 1 of this invention formed in this way, the conductor 2 and the insulating layer 3 are in close contact with each other without any gaps, so that no air can enter through the gaps. Since conductive paths and semi-conductive paths are not formed by intermediate substances or conductive substances, and since there is no space between the insulating layers 3, mechanical stress such as vibration or deformation at the cable side end 7 etc. is prevented. Sufficient insulation can be ensured without causing interlayer peeling.

On the other hand, in the conventional flat cable 10 whose partial cross-sectional view is shown in FIG. A void 13 having a triangular cross section is created between 12 and 12.

Therefore, substances forming a conductive path or a semi-conductive path may enter through this void 13, and the void 13 may expand due to mechanical stress such as vibration or deformation at the cable side end 14, causing the insulating layer to This caused peeling between the 12 layers, which caused problems in ensuring insulation.

According to the flat cable 1 according to this invention,
In addition to solving these conventional problems, the conductor position accuracy can be increased, the contact surface area of the insulating layer can be increased, and most of the external force applied to the cable is supported by the insulating layer, so the stress burden on the conductor is reduced. It becomes a flat cable that is lighter and less prone to disconnections.

Note that this invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the idea of this invention.

[Effect of idea]

As described above, this invention is made up of a plurality of conductors arranged in parallel and spaced apart, and an insulating layer made of a thermoplastic resin film that sandwiches the plurality of conductors, and the insulating layer covers the original film over a certain width at the conductor position. By configuring a flat cable that includes an original shape maintaining part that maintains almost the same thickness, and a thin part that has a substantially concave arc shape and is press-welded in the direction of the conductor as well as the thickness direction adjacent to the conductor position, the insulating layers are not accidentally connected to each other. Since there is no space between the conductor and the insulating layer by placing them in close contact, there is no infiltration of conductive or semiconducting material from the cable end, and the cable side end does not peel off, making it difficult for insulation defects to occur. Furthermore, it is possible to provide a flat cable with high conductor position accuracy, a light stress burden on the conductor, and no connection failures due to vibration, corrosion, disconnection, etc.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a flat cable according to an embodiment of this invention, and FIG. 2 is a partial cross-sectional view of a conventional flat cable. 1...Flat cable, 2...Conductor, 3...
Insulating layer, 4... Original shape maintaining part, 5... Thin wall part.

Claims (1)

[Scope of utility model registration request] It consists of a plurality of conductors arranged in parallel and spaced apart, and an insulating layer made of a thermoplastic resin film that sandwiches the plurality of conductors, and the insulating layer has an original shape maintaining part that substantially maintains the original film thickness over a certain width of the conductor position. , a flat cable comprising a substantially concave arc-shaped thin section that is press-molded in the direction of the conductor as well as in the thickness direction adjacent to the conductor position.