JP2573754B2 - Multi-core cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-core cable which is particularly required to have flexibility and noise prevention, such as in electronic equipment such as medical equipment and measuring equipment or between equipment.

[0002]

2. Description of the Related Art A multi-core cable used for wiring in an electronic device or wiring between devices has a high flexibility in handling, and a movement such as bending is frequently applied. When a motion such as bending is applied, the electric wires constituting the multi-core cable are rubbed against each other to generate static electricity, which affects the central conductor for transmitting the signal and the ground, and causes noise to the signal.

[0003]

When a motion such as bending is applied to a multi-core cable, electric wires are rubbed against each other to generate static electricity, which affects the central conductor for transmitting signals and the ground, and causes noise to the signals. Has been known for some time. Therefore, as a countermeasure, it has been considered that each core is shielded by a horizontal winding wire or the like, and this is further combined to form a multi-core cable. However, with the increase in accuracy of medical equipment and measurement equipment, multi-core cables used in those equipments or between equipments are not shielded by each core due to horizontal winding etc. Has become a problem, and countermeasures have become necessary.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a multi-core device which does not generate the above-mentioned noise even when a motion such as bending is applied in applications requiring high precision, such as medical equipment and measuring equipment. The purpose of which is to obtain a cable, characterized in that after applying an antistatic material to the outer surface of each core, a multi-core wire is twisted, and more preferably, the assembly is made of a conductive tape. This is a multi-core cable that is held down by winding.

[0005]

[Function] After applying an antistatic material to the outer surface of each core, since it is a multi-core cable in which a number of wires are twisted, even if a motion such as bending is applied, there is almost no generation of static electricity. There is almost no generation of noise. In addition, even if some static electricity is generated, it is possible to more completely escape to the outside of the cable through the collective shield by using the conductive tape which is wound and suppressed. Further, even when an antistatic agent is applied to the outer surface of each core, there is almost no change in the stiffness, and a predetermined flexibility can be maintained.

[0006]

EXAMPLE A center conductor 1 was formed from seven tin-plated annealed copper wires of 0.05 mm, and a fluororesin was extruded as an insulator 2 to finish to an outer diameter of about 0.38 mm. This insulated wire is covered with a transversely wound wire 3 with a pitch of about 9 mm using a tinned annealed copper wire of 0.03 mm as a shield, and two 4 μm thick, 2.5 mm width polyester tapes are wrapped as a jacket 4 and then heat-treated. Integrated and finished coaxial core.

After an antistatic agent was applied to the surface of the outer cover 4 of the above-mentioned coaxial core, they were twisted in the following procedure. That is, the above-mentioned 16 coaxial cores were twisted together to obtain an A-core figure 2 (a). Next, the above-mentioned four coaxial cores are twisted to form a B-core diagram 2
(B). Then, 4 units of the B core and 7 units of the A core were combined as shown in FIG. 2 (c). On these assemblies, a thickness of 50 μm, a width of 25 mm, and a volume resistivity of 1.3 ×
A conductive tape 5 of about 10 ² (Ω-cm) was suppressed and wound in about 1/3 overlap. Furthermore, the wire diameter is 120μ for shielding.
Braid 6 with a pitch of about 65 mm
Was given. The outer periphery of the braid 6 was extruded and coated with a polyvinyl chloride resin composition to a thickness of about 0.7 mm to form a jacket 7, and the multicore cable of the present invention was finished with a final outer diameter of about 9.4mm. (Hereinafter referred to as the multi-core cable of the present invention)

The feature of the multi-core cable of the present invention is that after coating an antistatic agent on the outer surface of the coaxial core, the coaxial core is joined by multi-core, and the joined assembly is suppressed and wound with a conductive tape. However, as the antistatic agent, those commercially available as so-called external antistatic agents can be used. Specifically, for example, Nalauryl aminoprop
ionate, Diethanolamine salt lauryl amino propionate
For example, it is preferable that a cation having a high adsorptive power and an amphoteric surfactant are dissolved in a low-boiling organic solvent, and this is applied to the outer surface of the coaxial core.

Next, as with the multi-core cable of the present invention,
An antistatic agent was not applied to the outer surface of the coaxial cable to form a multi-core cable that was assembled without applying an antistatic agent, and the assembly was suppressed and wound with a normal non-conductive Teflon tape. (Hereinafter referred to as the multi-core cable of the comparative example)

In order to confirm the effect of the present invention, the multi-core cable of the present invention and the multi-core cable of the comparative example were similarly bent, and the noise generated at that time was measured. FIG.
Indicates that the measurement is being performed. That is, a multi-core cable sample of about 1.5 m is mounted on a bending tester, and a substantially central portion of the multi-core cable is fixed by a mandrel 8 having a diameter of 12.5 mm, and a portion other than the bent portion is fixed to a fixing table 9. Then, mount the sample so that no motion other than bending by the tester is applied to the sample. The movement of the bent portion was performed mechanically and reciprocated at an angle of ± 90 ° at a speed of 30 times per minute. In addition, the shielding braid 6 covering the cable assembly from the sample end on the fixed side is grounded, and then one coaxial core is taken out. It was connected to the positive side of the linear coder F, and the voltage generated during the bending motion was measured. As a result, as shown in FIG. 4, the maximum voltage of 4.25 mV was generated in the case of the multi-core cable of the comparative example, whereas the maximum value of 0.575 mV was obtained in the case of the multi-core cable of the present invention. Only an electrostatic voltage was generated.

[0011]

As described in the embodiments, the multi-core cable according to the present invention is significantly less likely to generate noise due to bending than the multi-core cable of the comparative example. In addition, the handling is easy without bending flexibility being much different from the conventional one.

[Brief description of the drawings]

FIG. 1 is a partially cutaway schematic view of a coaxial core constituting a multi-core cable of the present invention.

FIG. 2A shows a cross section of an A core obtained by assembling 16 coaxial cores. (B) shows a cross section of a B core obtained by assembling four coaxial cores. (C) shows a cross section of the multi-core cable of the present invention.

FIG. 3 shows a state in which noise is measured while bending the multi-core cable.

FIG. 4 shows the results of measuring noise characteristics when bending the multi-core cable of the present invention and the multi-core cable of the comparative example.

[Explanation of symbols]

1: Center conductor 2: Insulator 3: Horizontal winding 4: Coaxial core jacket 5: Holding tape 6: Braid for shielding 7: Multi-core cable jacket 8: Mandrel 9: Fixed base 10: Measuring instrument (Graphtec) TYPE WR370
1 Linear coder F)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuhiro Sato 1-chome, Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (56) References Shokai 57-171220 (JP, U) Shokai Shokai 55-5468 (JP, U) Actually open 1981-48813 (JP, U)

Claims (1)

(57) [Claims] 1. A multi-core cable, comprising: a multi-core cable formed by twisting and gathering, wherein an antistatic agent is provided on the outer surface of each electric wire, and a conductive tape is used as a holding tape. cable.