JPH0722017Y2 - Pressure-sensitive striatum - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a pressure-sensitive linear body that is uniformly sensitive to pressure at all continuous positions in the longitudinal direction.

[Conventional technology and its problems]

The applicant of the present application has proposed this type of pressure-sensitive linear member P in Japanese Utility Model Publication Nos. 62-31830 and 62-31831. The former is
Explaining with reference to FIG. 1, on one circumference of the flexible electric conductor,
Inner elastic conductive layer 2, braided layer of electrically insulating yarn (air insulating layer)
3, the outer elastic conductive layer 4 is sequentially provided, and the outer elastic conductive layer 4
The metal foil strip 5 is vertically attached or wrapped around the outer surface of the above, and a protective jacket 6 is provided around the metal foil strip 5. The latter will be described with reference to FIG. The two core wires a, in which the elastic conductive layer 2 and the braided layer 3 of electrically insulating yarn are sequentially provided, are twisted together, and the protective jacket 6 is provided around them.

Both of these pressure-sensitive striatum P have been highly evaluated as such,
The pressure-sensitive accuracy is not fully satisfactory. That is, the elastic conductive layers 2 and 4 bite into the braided layer 3 of the electrically insulating yarn even in a normal state, and a malfunction such as conduction occurs with a small pressure.

An object of the present invention is to prevent the elastic conductive layers 2 and 4 from biting into the braided layer 3 at normal times.

[Means for Solving the Problems]

First, when the present inventors look at the conventional braided layer 3,
The braided yarn is a sweet twist, a normal twist (twist ratio: about 1.15)
Based on the weakness of the twist, the braided layer is usually
For example, even when the strands are twisted when they are manufactured,
In order to solve the above-mentioned problems by discovering that the above-mentioned malfunction occurs, in the present invention, in the above-mentioned pressure-sensitive linear body, the electrically insulating yarn is used as a strong twist yarn (strong yarn), and the strong twist yarn is used. The braid (air insulating layer) 3 is constituted by the above.

The above-mentioned strongly twisted yarn means, in terms of twist ratio, 1.20 or more, and the twist ratio will be described with reference to Examples.
When twisting 1000D x 2 strands / three strands, assuming that the weight per 1m of the yarn before twisting is W and the weight per 1m of the twisted yarn after twisting is w, the twisting ratio is w / W It is represented by.

[Action]

In the pressure-sensitive linear member according to the present invention having such a structure, since the braid thereof is made of the strongly twisted yarn, "settling" does not occur, and the elastic conductive layer does not bite in the normal condition.

〔Example〕

In FIG. 1, reference numeral 1 is a center conductor, which is formed by twisting seven 0.6 mm tin-plated annealed copper wires (2.0 mm ² ). On this central conductor 1, a conductive silicone rubber composition having a volume-specific low efficiency of 4 Ω-cm was extruded in a thickness of 0.8 mm and subjected to a cross-linking treatment to form an inner elastic conductive layer 2, on which the structure shown in Table 1 below was formed. An insulating braid layer 3 made of Tetoron yarn was formed.

Then, a conductive silicone rubber composition similar to the above was added to 0.8 m
Extrusion molding with a thickness of m and crosslinking treatment to form the outer elastic conductive layer 4 on which the vinyl chloride mixture (Sumiflex manufactured by Sumitomo Chemical) is extruded while covering the tin-plated annealed copper wire braided conductor 5. The protective jacket 6 was molded to obtain the pressure-sensitive linear member P according to the present invention. As a comparative example, an insulating braided layer 3 having a sweet twist (twisting ratio: 1.15) was also manufactured in the same manner.

In this embodiment, when the outer elastic conductive layer 4 is pressure-heated and cross-linked by heating, the conductive rubber is embedded in the gap of the Tetron braided layer 3 and the desired pressure-sensitive cable P cannot be obtained. Therefore, in the extrusion molding, hot-wire crosslinking was performed using a pipe extrusion die nipple. If it is unavoidable that pressure crosslinking is unavoidable, it is necessary to seal an inert gas inside to prevent the above bite.

Examples 1 and 2 and Comparative Examples 1 and 2 configured as described above
When pressure was applied by bending pressure, static pressure or the like, in both examples, the inner and outer elastic conductive layers 2 and 4 penetrated into the gap between the braid layers 3 and good conduction was obtained. On the other hand, Comparative Examples 1 and 2
However, the operation was unstable, such as the appearance of a large outer diameter caused a fatigue and short circuit with a small pressure.

The braid density F of the Tetoron braided layer 3 is 60%, 54%,
Good results were obtained at any of 50%. That is, the braid density is preferably 35 to 80, as in the technique described in the above publication.

The braid density F was calculated by the following formula.

θ: Braid angle D: Braid average diameter (braid bottom diameter + 2d) d: Braid wire diameter or braid tape thickness L: Braid pitch p: the number of crossings per unit length m: the number of strokes w: nd or the width of the braided tape n: the number of braids In this embodiment, the braided conductor 5 is replaced by a vertically attached layer or a wound layer such as a metal foil strip. You can also

In the embodiment shown in FIG. 2, the elastic conductive layer 2 and the braided layer 3 of insulating fiber yarn are sequentially provided on the circumference of the central conductor 1 with the same material and structure as the above embodiment to form the core a. The two core wires a are twisted together with the jute 7 interposed at a pitch of a layer core diameter of 8, 12, 20, 26, and 35 times, and a polyester non-woven tape 8 (0.15 mm thick) is provided around the same for 4 minutes. After being wound with one wrap, the pressure-sensitive linear body P is provided with the protective jacket 6.

In the case of this embodiment, the braided layer 3 is used as in the technique described in the above publication.
It is preferable that the braid density is 17 to 40, and the strand twist pitch is 10 to 30 times the layer core diameter.

Also in this example, when the braided layer 3 having the four kinds of configurations shown in Table 1 was manufactured, the same result as that of the example was obtained.

In both examples, if the twist of the yarn of the braid layer 3 is fixed by heat treatment, the malfunction can be further reduced.

[Effect of device]

Since the present invention is configured as described above and prevents the elastic conductive layer from normally digging into the air insulating layer (electrically insulating yarn braided layer), malfunction is eliminated and reliability is improved as compared with the conventional one. It will be expensive.

[Brief description of drawings]

1 and 2 are cross-sectional views of respective embodiments of the pressure-sensitive linear member according to the present invention. a: core wire, P: pressure-sensitive linear body, 1 ... electric conductor (center conductor), 2, 4 ... elastic conductive layer, 3 ... air insulating layer (insulating braid layer), 5 ... braid Conductor, 6 ... Protective jacket, 7 ...
Jute, 8 ... Nonwoven tape.

Claims (2)

[Scope of utility model registration request] 1. An electric conductor serving as one electrode
On the coaxial circumference, an inner elastic conductive layer, an air insulating layer, an outer elastic conductive layer, and an electric conductor to be the other electrode are sequentially provided,
In the pressure-sensitive linear body with a protective jacket around this,
A pressure-sensitive linear member, characterized in that the air insulating layer is formed by braiding electrically insulating strong twisted yarns. 2. An elastic conductor layer and a braid layer of electrically insulating hard-twisted yarn are sequentially twisted on the circumference of an electric conductor, and two core wires are twisted together, and a protective jacket is provided around the core wire. Pressure-sensitive striatum.