JP2003227585A - Flexible pipe and light guide using the flexible pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic flexible pipe having excellent bending performance, and also to provide a light guide internally storing optical fibers and having excellent bending performance. <P>SOLUTION: The flexible pipe 1 is formed by winding a strip-shaped metallic plate in a spiral and caulking a caulking upper portion 11 in an upper side of a superimposing part and a caulking lower portion 12 in a lower side. When the flexible pipe 1 is bent, a relative position is changed so as to shift the caulking upper portion 11 and the caulking lower portion 12 while contacting each other. A plurality of optical fibers 21 are inserted into the flexible pipe 1 in a bundle, and twisted at constant pitches. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible tube made of metal and a light guide having an optical fiber built therein.

[0002]

2. Description of the Related Art In addition to being used for water and gas piping, metal flexible pipes are used for applications in which filaments such as copper wires and optical fibers are incorporated. Especially in light guides with built-in optical fibers for transmitting optical energy, heat resistance is required due to high temperatures during optical transmission, so multiple flexible pipes made of metal with a heat-resistant coating such as fluororesin are required. It has a structure in which a quartz optical fiber of a book is bundled and stored. The flexible tube is generally formed by spirally winding a strip-shaped metal plate and caulking the overlapped portions to form the tube.

FIG. 5 is a vertical sectional view showing the structure of a conventional light guide. A plurality of optical fibers 21 are inserted inside the flexible tube 40. Flexible tube 40
Is an upper part of the overlapping part of the spirally wound metal plates, and the upper part 11 of the caulking is formed so as to be convex outward in a U shape, and is bent at an acute angle which is a lower part of the overlapping part of the metal plates. The caulked lower portion 12 is firmly caulked with the caulked lower portion 12 so that the caulked portion does not come off when the flexible tube 40 is pulled.

[0004]

In the case of a light guide attached to manufacturing equipment such as a semiconductor manufacturing apparatus, a flexible tube having excellent bending characteristics is required from the viewpoint of handleability. The conventional flexible tube has a drawback that it is difficult to bend because the caulking portion is firmly caulked. Further, there is a problem that the optical fiber housed inside the flexible tube is easily located at a position along the inner wall of the flexible tube, and the bending property deteriorates due to the rigidity of the optical fiber itself.

It is an object of the present invention to provide a metal flexible tube having excellent bending characteristics and a light guide having an excellent bending characteristic in which an optical fiber is housed therein.

[0006]

The flexible tube of the present invention is formed by spirally winding a strip-shaped metal plate and crimping the upper crimping upper portion and the lower crimping lower portion of the overlapping portion. When the flexible tube is bent, the relative positions of the upper part of the caulking and the lower part of the caulking are changed. The relative positions of the upper part of the caulking and the lower part of the caulking change in a direction in which they are displaced while contacting each other. Alternatively, the relative position changes in the direction in which the angle formed by each of the contact portions is changed as the base point.

It is preferable that the upper part of the crimp is formed in a U-shape so as to be convex outward, and the lower part of the crimp is bent at a constant bending angle of 90 ° or less in the longitudinal direction.

The bending angle at which the end of the lower part of the caulking is bent is preferably 30 ° or more and 90 ° or less.

The flexible tube of the present invention is effective in a light guide in which at least one optical fiber is inserted, since the bending characteristics are remarkably improved.

It is preferable that the optical fibers to be inserted into the flexible tube are bundled in such a number that the filling rate is 15% or more, and the optical fibers are twisted at a constant pitch.

The twist pitch of the optical fiber is preferably 150 mm or more and 400 mm or less.

The length of the optical fiber is preferably 95% or more and 105% or less of the length of the flexible tube.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A flexible pipe of the present invention will be described with reference to the drawings. FIG. 1 is a vertical sectional view showing an embodiment of the flexible tube of the present invention. Flexible tube 1
It is formed by spirally winding a strip-shaped metal plate and crimping the upper crimping portion 11 and the lower crimping portion 12 on the upper side of the overlapping portion. When the flexible tube 1 is bent, the relative position changes in a direction in which the lower portion 12 of the caulking portion comes in contact with the end portion of the upper portion 11 of the caulking portion, and thus the relative position changes, which facilitates bending. Alternatively, when the contact portions of the caulking upper portion 11 and the caulking lower portion 12 are in strong contact with each other, the relative position changes in a direction in which the angle formed by the caulking upper portion 11 and the caulking lower portion 12 expands with the contact portion as a base point. When the bending stress is released, it is preferable that the relative positions of the caulking upper portion 11 and the caulking lower portion 12 return to their original positions.

The caulking upper part 11 is formed in a U-shape so as to be convex outward, and the caulking lower part 12 is bent at its end so as to form a constant bending angle B1 of 90 ° or less,
The caulking is performed in a state where only the end of the caulking upper portion 11 is in contact.

The bending angle B1 at the end of the caulking lower portion 12 is
It is preferably 30 ° or more and 90 ° or less. When the angle is 90 ° or more, since the caulking upper portion 11 and the caulking lower portion 12 are firmly crimped, when the flexible tube 1 is bent, the caulking portion becomes hard to move and becomes difficult to bend. When the angle is 30 ° or less, the caulked portion is likely to come off when the flexible tube 1 is pulled.

The bending angle A1 at the end of the caulking upper portion 11 is
It is preferably 60 ° or more and 90 ° or less. When the angle is 90 ° or more, since the caulking upper portion 11 and the caulking lower portion 12 are firmly crimped, when the flexible tube 1 is bent, the caulking portion becomes hard to move and becomes difficult to bend. In the case of 60 ° or more, when the flexible tube 1 is pulled, the caulked portion is likely to come off.

The material of the flexible tube 1 is preferably stainless steel because of its strength and resistance to rust. The outer diameter of the flexible tube 1 is 2 mm to 50 mm depending on the outer diameter and the number of optical fibers housed inside.

FIG. 2 is a vertical sectional view showing another embodiment of the flexible tube of the present invention. The ends of the caulking upper portion 11 and the ends of the caulking lower portion 12 of the flexible tube 2 are crimped so as to be in surface-to-face contact with each other. When the flexible tube 2 is bent, the ends of the caulking upper part 11 and the ends of the caulking lower part 12 slide while being in contact with each other, which facilitates bending.

It is preferable that the bending angle A2 at the upper end of the caulking and the bending angle B2 at the lower end of the caulking are bent at the same angle of 90 ° or less. Especially 30 ° or more and 90 °
The following are preferred. In case of 90 ° or more, caulking upper part 11
Since the caulking of the caulking lower portion 12 is strong, when the flexible tube 2 is bent, the caulking portion becomes difficult to move and becomes difficult to bend. When the angle is 30 ° or less, the caulked portion is likely to come off when the flexible tube 2 is pulled.

FIG. 3 is a cross-sectional view showing an embodiment of the light guide of the present invention. The filling rate of the optical fiber 21 in the space inside the flexible tube 1 is preferably 15% or more. When the filling rate is 15% or less, the optical fiber 21 is likely to be located in the vicinity of the inner wall of the flexible tube 1, and the rigidity of the optical fiber 21 causes the light guide 20 to move.
Becomes difficult to bend.

The optical fiber 21 inserted into the flexible tube 1 has a diameter of 0.125 mm to 0.880 mm.
The outer periphery of the glass fiber 22 is coated with an outer diameter of 0.
It is 25 mm to 1.40 mm. The coating may be provided in two or more layers as required. As the material provided for the coating, a thermosetting resin such as a silicone resin, an ultraviolet curing resin such as a urethane acrylate,
A thermoplastic resin such as polyamide or fluororesin is used. In particular, for applications requiring heat resistance, a silicone resin primary coating 23 is provided, and a fluorine resin secondary coating 24 is provided on the outer periphery thereof.

FIG. 4 is a vertical sectional view of the light guide shown in FIG. The plurality of optical fibers 21 housed inside the flexible tube 1 are twisted at a constant pitch. By twisting the optical fiber 21, it is possible to prevent the optical fiber 21 from being positioned near the inner wall of the flexible tube 1. When the light guide 20 is bent, the caulking upper portion 11 and the caulking lower portion 12 of the flexible tube 1 slide to bend the flexible tube without difficulty, and the rigid optical fiber 21 does not exist near the inner wall of the flexible tube 1. Therefore, the optical fiber 21 will not be pressed near the inner wall of the flexible tube 1, and the bending of the light guide 20 will not be restricted by the optical fiber 21 hitting the bent inner wall. Twist pitch is 150 mm
It is preferably 400 mm or less. When the twist pitch is 150 mm or less, the plurality of optical fibers 21 are integrated into a rod shape, so the light guide 20
Is hard to bend. If it is 400 mm or more, the effect of twisting is small, and the optical fibers 21 are likely to gather near the inner wall of the flexible tube 1.

In the light guide, the bases are attached to both ends of the flexible tube, the optical fiber is cut to an appropriate length, and then a connector is attached to the ends as needed. The length of the optical fiber is preferably 95% or more and 105% or less with respect to the length of the flexible tube. 9
When it is 5% or less, the optical fiber is too short for the flexible tube, so that when the flexible tube is bent, stress is easily applied to the optical fiber and the optical fiber is easily broken. If it is 105% or more, the excess length of the optical fiber is too long, and the optical fiber is likely to be distorted.

The light guide of the present invention has a diameter of 120 mm.
Since it can be wound around the following diameters, it has excellent storability during packaging and can be installed in a narrow space even when used in a manufacturing apparatus or the like.

[0025]

EXAMPLE A strip-shaped stainless plate was spirally wound and the overlapping portion was caulked to obtain a flexible tube 1 shown in FIG. The caulking upper portion 11 was formed in a U-shape with the end bending angle A1 set to 80 °. The caulking lower part 12 has a bending angle B1 of 60 ° at the end, and the caulking upper part 11 and the caulking lower part 1
I cried 2. The flexible tube had an outer diameter of 5.0 mm and an inner diameter of 3.5 mm.

Four optical fibers 21 were inserted into the inside of the flexible tube 1 to prepare a light guide 20 having a horizontal cross section shown in FIG. 3 and a vertical cross section shown in FIG. Optical fiber 21 has an outer diameter of 0.4
A primary coating 23 made of silicon resin was provided on the outer circumference of the 4-mm glass fiber 22, and a secondary coating 24 made of fluororesin was further provided on the outer circumference thereof to have an outer diameter of 0.80 mm. The four optical fibers 21 were twisted at a pitch of 300 mm and then inserted into the flexible tube 1.

When the light guide 20 is wound around a mandrel having a diameter of 120 mm, the relative position changes so that the caulking upper part 11 and the caulking lower part 12 of the flexible tube 1 are displaced while being in contact with each other, and the flexible tube can be bent without difficulty. It was Further, the optical fiber 21 is prevented from being pressed toward the inner wall of the flexible tube 1, and the bent inner wall is hit by the optical fiber 21 so that the light guide 2
The 0 bend is no longer restricted.

[0028]

In the flexible tube and the light guide of the present invention, the flexible tube is formed by spirally winding a strip-shaped metal plate and crimping the upper crimping upper portion and the lower crimping lower portion of the overlapping portion. When the flexible pipe is bent, the relative positions of the upper part of the caulking and the lower part of the caulking change so that the bending is easy. Since the light guide of the present invention can be wound around a diameter of 120 mm or less, it has excellent storability at the time of packaging and can be installed in a narrow space even when used in a manufacturing apparatus or the like.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a flexible tube of the present invention.

FIG. 2 is a vertical cross-sectional view showing another embodiment of the flexible tube of the present invention.

FIG. 3 is a cross-sectional view showing an embodiment of the light guide of the present invention.

FIG. 4 is a vertical sectional view showing an embodiment of the light guide of the present invention.

FIG. 5 is a vertical sectional view showing a conventional light guide.

[Explanation of symbols]

1,2 flexible pipe 11 Upper part of caulking 12 Lower crimp 20 Light guide 21 optical fiber 22 glass fiber 23 Primary coating 24 Secondary coating 40 flexible tube Bending angle of A1, A2 caulking upper part B1, B2 Bending angle of lower caulking

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H046 AA03 AA22 AA62 AB08 AD20                 3H111 AA01 BA01 CA06 CA09 CA33                       CA37 CA42 CA55 CB02 CB14                       DB23 EA09

Claims (7)

[Claims] 1. A flexible pipe manufactured by spirally winding a strip-shaped metal plate and crimping the overlapping portion, wherein the relative positions of the upper crimping upper portion and the lower crimping lower portion of the overlapping portion of the metal plate are the flexible positions. A flexible tube that changes when a bending stress is applied to the tube. 2. The caulking upper portion is formed in a U shape so as to be convex outward, and the caulking lower portion has its end portion bent at a constant bending angle of 90 ° or less over the longitudinal direction. The flexible tube according to claim 1, which is characterized in that. 3. The bending angle of the lower end of the caulking is 3
The flexible pipe according to claim 2, wherein the flexible pipe has an angle of 0 ° or more and 90 ° or less. 4. A light guide, characterized in that at least one optical fiber is built in the flexible tube according to any one of claims 1 to 3. 5. The filling rate of the optical fiber in the space inside the flexible tube is 15% or more, and a plurality of the optical fibers are twisted at a constant pitch. Light guide. 6. The twist pitch of the optical fiber is 150.
The light guide according to claim 5, wherein the light guide has a length of at least mm and at most 400 mm. 7. The light guide according to claim 4, wherein the length of the optical fiber is 95% or more and 105% or less with respect to the length of the flexible tube.