JPH0461447B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method of manufacturing a flat cable used for connecting various electronic devices such as computers and data transmission devices.

[Prior art and its problems]

Generally, flat cables are used in various electronic devices for internal wiring and for interconnecting devices.

As shown in Figure 1, this flat cable is
A plurality of core wires 1 each having an insulating coating 1b made of a soft synthetic resin such as polyvinyl chloride on a conductor 1a...
are lined up in parallel and the side surfaces of their synthetic resin insulating coatings are glued or heat-sealed to each other, or multiple conductors are lined up in parallel and integrally insulated by extrusion shaping, etc. Some are coated.

Among these methods, for example, the method shown in Fig. 2 is known as a method of manufacturing a so-called fusion-type flat cable in which the insulation coatings of adjacent core wires are joined and integrated by heat fusion. ing.

In FIG. 2, reference numerals 2 and 2 denote a pair of heat-sealing rolls for integrally fixing the plurality of core wires 1 arranged in parallel by heat-sealing to form a flat cable 3. It shows.

These heat-sealing rolls 2, 2 each have an annular groove with a small semicircular cross section in the longitudinal direction on their outer peripheries for sandwiching, heat-sealing, and sending out the core wire 1 as they rotate. are formed at equal intervals, and the grooves are aligned with each other,
They are arranged parallel to each other with a slight distance between them. The surfaces of these heat fusing rolls 2, 2 are heated to approximately 200° C. by a heat source (not shown).

Accordingly, as the heat-sealing rolls 2, 2 rotate, the plurality of core wires 1 arranged in parallel with each other are sandwiched between the grooves between the heat-sealing rolls 2, 2, and the respective core wires 1 are The surface of the insulating coating made of synthetic resin such as polyvinyl chloride is melted by the heat of the heated surfaces of the heat fusing rolls 2, 2. These core wires 1... are lightly pressed between the heat fusing rolls 2, 2, so that the melted resin of the insulation coating is bonded between the heat fusing rolls 2, 2 on each side. They bulge out between the two and fuse together. In this way, the core wires 1... are fused at their side surfaces to each other by the heat fusing rolls 2, 2, and become an integral piece, forming a flat cable 3, which is formed by the heat fusing rolls 2, 2. sent out from between. And these heat fusion rolls 2,
The flat cable 3 sent out from between the two is successively guided to grooved shaping rolls 4, 4 provided after the heat-sealing rolls 2, 2.

These grooved shaping rolls 4, 4 cool the flat cable 3 sent out from the heat fusion rolls 2, 2, and simultaneously solidify the resin of the insulation coating, which has just been fused and has been softened. , for correcting the pitch between the core wires, and are a pair of rolls having grooves similar to those of the heat fusing rolls 2, 2 described above. With these grooved shaping rolls 4, 4,
The flat cable 3, whose insulation coating has a temperature of about 150°C, is sent out from the heat-sealing rolls 2, 2.
The core wires are passed through the grooves of the grooved shaping rolls 4, 4, which have the same pitch between the core wires as the heat-sealing rolls 2, 2, and the core wires are rubbed again, the pitch is corrected, and the core wires are cooled to form the fused portion. It is solidified and ready to be taken out.

However, in such a conventional flat cable manufacturing method, since the flat cable 3 is heated to about 150°C when it is sent out from the heat sealing rolls 2, 2, the Due to heat conduction, the surfaces of these grooved shaping rolls 4, 4 are also gradually heated. As a result, a sufficient cooling effect gradually becomes impossible to obtain, and the flat cable 3 ends up passing through the grooved shaping rolls 4, 4 without the resin of its insulating coating being sufficiently solidified.

However, in this way, the flat cable 3, which was sent out from the grooved shaping rolls 4, 4 without the resin of the insulation coating being sufficiently cooled and solidified, was allowed to cool naturally and the fused insulation coating was removed. If the resin is solidified, the rate of temperature drop will be different between the center and both sides of the flat cable 3.

Therefore, in this flat cable 3, the solidification speed of the resin of the insulation coating at each position is slowed down. As a result, the pitch between the core wires becomes wider at the center and narrower at both sides compared to the regular dimensions immediately after manufacture, which is a problem for this type of flat cable. There was a problem in that it became difficult to keep the pitch between the core wires, which is a quality requirement for standardization, within an allowable range of, for example, 1.27±0.08 mm, resulting in a considerable number of defective products.

On the other hand, in order to quickly and reliably cool and solidify the flat cable 3 after it has been heat-sealed,
When the flat cable 3 sent out from between the heat sealing rolls 2 and 2 is rapidly cooled, the resin of its insulation coating is rapidly cooled and solidified. Therefore, a constrained strain, ie, residual stress, remains inside the resin.
In the flat cable manufactured in this manner, the pitch between the core wires is stable within the standard value immediately after manufacture. However, with such a flat cable, when the ambient temperature rises to around 60°C during storage, for example, the internal strain restrained inside the resin changes to alleviate this strain, causing the flat cable to become flat. The problem was that the pitch between the core wires of the cable changed.

[Purpose of the invention]

This invention was made in view of the above circumstances,
The object of the present invention is to provide a method for manufacturing a flat cable that is stable even when the pitch between core wires is within the allowable range of standard values, and that has no residual stress in the heat-sealed part. be.

[Structure of the invention]

The method for manufacturing a flat cable of the present invention includes arranging a plurality of core wires in parallel, heat-sealing these core wires to each other between heat-sealing rolls, and then guiding these core wires between grooved shaping rolls. In the method of manufacturing a flat cable by correcting the pitch between each core wire, the grooved shaping roll is heated at 50°C to
The grooved shaping roll is placed in hot water of 80°C and is constantly cooled by the hot water so that the temperature of the grooved shaping roll is almost equal to the warm water, while the grooved shaping roll corrects the pitch between each core wire, and at the same time The gist is to cool down the core wire group using the hot water.

[Embodiments of the invention]

FIG. 3 shows an embodiment of the flat cable manufacturing method of the present invention, and parts common to those shown in FIGS. 1 and 2 are given the same reference numerals and their explanations are simplified. become

In the manufacturing method shown in FIG. 3, the above-mentioned grooved shaping rolls 4, 4 are placed in hot water 5 in a hot water tank 6 filled with hot water 5 at 50°C to 80°C.

In such a manufacturing method, the heat fusing rolls 2, 2
The flat cable 3 which has been thermally fused therebetween and sent out is passed between the grooved shaping rolls 4, 4 in a hot water tank 6 filled with hot water 5 at 50 DEG C. to 80 DEG C. As a result, the flat cable 3, which was heated to about 150°C at the position where it was sent out from the heat fusion rolls 2, 2, is heated by the hot water 5.
It is once cooled at a temperature of 50°C to 80°C. That is, this flat cable 3 is placed in the hot water 5 and its core wire 1 is inserted into the groove of the grooved shaping rolls 4, 4 whose surface temperature is 50°C to 80°C.
While correcting the pitch, the resin is cooled somewhat slowly by the hot water 5, and the softened resin is solidified.

At this time, if the temperature of the hot water 5 exceeds 80°C, the resin of the flat cable 3 will not be able to sufficiently cool and solidify, and will be naturally cooled after passing through the grooved shaping rolls 4, 4. Become,
Therefore, as mentioned above, the pitch between the core wires changes over time, which is inappropriate. Also, the temperature
If the temperature is less than 50°C, the resin of the flat cable 3 will be rapidly cooled and solidified, and as mentioned above, residual stress will be generated inside the cable, making it unsuitable. Therefore, the temperature of this hot water 5 should be 50℃~
By constantly maintaining the temperature at 80℃, flat cable 3
Because the resin is cooled and solidified at a moderate speed,
A flat cable 3 having a constant pitch between core wires and having no internal residual stress can be manufactured.

〔Effect of the invention〕

According to this invention, a plurality of core wires are arranged in parallel,
In a method of manufacturing a flat cable by heat-sealing these core wires to each other between heat-sealing rolls, and then guiding these core wires between grooved shaping rolls to correct the pitch between each core wire, The grooved shaping roll is placed in hot water of 50°C to 80°C, and while being constantly cooled by the warm water so that the temperature of the grooved shaping roll is approximately equal to the warm water, each core wire is Since the structure is configured to correct the pitch between the cables and at the same time slowly cool the core wire group using the hot water, (1) the correction of the pitch of the cable and the slow cooling can be performed at the same time, improving manufacturing efficiency; (2) As a result of the grooved shaping roll continuously coming into contact with the hot core wire group immediately after being heat-sealed, heat is accumulated in the grooved shaping roll and the temperature of the roll also rises to a high temperature; The grooved shaping roll itself is cooled by the hot water to the temperature of the hot water. Therefore, the process can always be carried out at the optimum temperature (50 to 80°C) for correcting the pitch between each core wire. temperature controlled. For this reason, the heat capacity of the entire hot water in the hot water tank is much larger than that of the roll itself, and therefore the temperature control of the liquid itself,
This makes it easier to control the temperature of the grooved shaping roll. (4) The high-temperature heat-sealed core wires are at the optimal temperature (50 to 80℃) for gradual cooling at the same time as pitch correction.
It passes through a hot water tank maintained at For this reason, the cooling time during which the core wire group is in contact with the hot water becomes longer, and as a result, the core wire group is sufficiently slowly cooled. Therefore, excellent effects such as almost no shrinkage or residual strain caused by air cooling are achieved.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of the flat cable, Figure 2
The figure is an explanatory diagram of a conventional flat cable manufacturing method, and FIG. 3 is an explanatory diagram of an embodiment of the flat cable manufacturing method of the present invention. 1 is a core wire, 2 is a heat sealing roll, 3 is a flat cable, 4 is a grooved shaping roll, 5 is hot water, and 6 is a hot water tank.

Claims (1)

[Claims] 1 After arranging a plurality of core wires in parallel and heat-sealing these core wires to each other between heat-sealing rolls,
In a method for manufacturing a flat cable by guiding these core wires between grooved shaping rolls and correcting the pitch between each core wire, the grooved shaping rolls are
The grooved shaping roll is placed in hot water of 50°C to 80°C, and the pitch between each core wire is corrected with the grooved shaping roll while constantly being cooled by the hot water so that the temperature of the grooved shaping roll is almost equal to the warm water. , and at the same time slowly cooling the core wire group with the hot water.