JP2505336B2 - Device and method for manufacturing metal tube coated optical fiber cable - Google Patents

Description

TECHNICAL FIELD The present invention relates to a manufacturing apparatus and a manufacturing method of a metal tube-coated optical fiber cable.

[Background Art] The breaking strength of an optical fiber is about 6 (k) at a diameter of 126 (μm).
g), which is quite large, but the elongation percentage when this tension is applied is 3 to 6%, which is significantly smaller than that of conventional cables such as copper and aluminum. Therefore, it is necessary to arrange a strength member on the optical fiber cable to secure the strength. Further, the strength of the optical fiber may deteriorate when immersed in water.
Therefore, when laying an optical fiber cable on the seabed or water bottom, it is necessary to use an optical fiber cable with a jacket structure in which the optical fiber cable is covered with a thin metal tube in order to secure the installation tension and water resistance. .

An apparatus and method for continuously producing an optical fiber cable coated with a metal tube as described above is disclosed in, for example, Japanese Patent Laid-Open No.
-35514.

This metal-coated optical fiber cable manufacturing apparatus forms a continuously fed flat metal strip into a metal tube having a vertical gap at the top. The introduction tube is inserted into the metal tube through the gap between the metal tubes, and the optical fiber is introduced into the metal tube by the introduction tube. After closing the gap of the metal tube into which the optical fiber is introduced, the metal tube is sent to the laser welding device.

The laser welding device welds the abutting portion by irradiating a laser beam having a focal point at a position distant from the surface of the abutting portion while positioning the abutting portion of the top of the sent metal tube by the guide roller. By defocusing the outer side of the abutting portion in this way, welding of the abutting portion is realized without protecting the optical fiber with the heat shielding material.

After the outer diameter of the metal tube containing the optical fiber cable is reduced to a predetermined size, the metal tube is wound around a capstan and continuously drawn out.

When pulling this metal tube, flow an inert gas into the introduction tube, carry the optical fiber cable with viscous resistance of the gas,
The fiber optic cable is blown outside the inner surface of the metal tube while the metal tube is engaged with the capstan so that the length of the fiber optic cable becomes longer than the metal tube when the metal tube is stretched. The fiber cable is slackened in the metal tube to prevent the optical fiber cable from being distorted due to laying tension or the like.

Furthermore, in order to prevent water from penetrating through the hole and degrading the optical fiber cable when the metal tube is damaged and a hole is opened, a gel is injected into the metal tube. That is, after the optical fiber cable is blown to the outside of the inner surface of the metal tube with an inert gas at the capstan, the gel is injected by a gel introduction tube different from the introduction tube for introducing the optical fiber cable.

However, the use conditions of the optical fiber cable are various and are used under various temperature conditions. And
The thermal expansion coefficient of the outer metal tube is much larger than that of the optical fiber cable. Therefore, when used at high temperature, tension acts on the optical fiber cable due to the difference in the degree of extension between the metal tube and the optical fiber cable, and the optical fiber cable is damaged. A similar phenomenon occurs when the cable is placed under high tension, for example, under the sea floor.

On the contrary, when used at low temperature, due to the difference in shrinkage between the metal tube and the optical fiber cable, the optical fiber cable comes into contact with the inner wall of the metal tube, which has a large amount of shrinkage, and receives the lateral pressure directly from the inner wall of the metal tube. However, irregular bending with a short cycle is added, so-called microbend loss occurs, and the strength of the signal passing through the optical fiber cable is attenuated.

In order to prevent such damages, conventionally, while the metal tube is engaged with the capstan, the optical fiber cable is blown to the outside of the inner surface of the metal tube, so that the length of the optical fiber cable is extended when the metal tube is extended. Is longer than the metal tube.

However, in this case, the difference in length between the optical fiber cable and the metal tube (hereinafter referred to as extra length) is determined by the outer diameter of the capstan and the difference between the inner diameter of the metal tube and the outer diameter of the optical fiber cable. The length cannot be controlled arbitrarily, and there is a risk that the optical fiber cable may be damaged depending on the usage conditions.

Further, while the metal tube is engaged with the capstan as described above, by blowing the optical fiber cable to the outside of the inner surface of the metal tube with an inert gas, the optical fiber cable has an extra length, so that the metal When injecting the gel into the tube, it was necessary to inject the gel in a state where the optical fiber cable was blown to the outside of the inner surface of the metal tube. That is, even if the gel is first injected and then the inert gas is sent, the gel becomes a resistance and the extra length cannot be given to the optical fiber cable. Therefore, in order to inject the gel, a gel introduction tube is required in addition to the optical fiber cable and the introduction tube for sending the inert gas. Therefore, the two introduction tubes must be passed through the metal tube, and the inner diameter of the metal tube becomes large. Therefore, there is also a disadvantage that the amount of squeezing when the metal tube is pulled out becomes large, and in some cases, the metal tube cannot be made thin according to the diameter of the optical fiber cable.

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above disadvantages, and it is possible to continuously operate for a long time without damaging an optical fiber cable at the time of welding a butt portion of a metal tube. It is an object of the present invention to provide a manufacturing apparatus and a manufacturing method of a metal tube-coated optical fiber cable capable of arbitrarily controlling an extra length.

An apparatus for manufacturing an optical fiber cable coated with a metal tube according to the present invention includes an assembly composed of a plurality of roller pairs that form a metal strip and abut both ends thereof to form a metal tube, and a laser beam to a butting portion of the metal tube. A device for manufacturing a metal tube-coated optical fiber cable, comprising laser welding means for irradiating and joining to form a sealed metal tube, and optical fiber introducing means for introducing an optical fiber or an optical fiber bundle into the metal tube. Tension adjusting means arranged in the preceding stage to adjust the tension of the metal tube by changing the tension of the metal strip on the inlet side of the assembly, and the tension of the optical fiber cable arranged in the preceding stage of the optical fiber introducing port of the optical fiber introducing means. And a tension adjusting means for varying the tension, and a traction means having a tension varying means for reducing the tension of the metal tube-coated optical fiber cable and sending it out. It is characterized by having.

The pulling means includes the assembly, the optical fiber introducing means,
Metal strip through laser welding means and drawing means,
It is preferable to reduce the tension of the metal-coated optical fiber cable by continuously pulling the molded metal tube and the sealed metal tube containing the optical fiber or the optical fiber bundle.

Further, it is preferable that the tension varying means is composed of a capstan formed by winding a metal tube-coated optical fiber cable a plurality of times.

Further, it is preferable to adjust the tension by a tension adjusting means provided on the downstream side of the tension varying means of the metal tube-coated optical fiber cable on the exit side of the tension varying means.

Further, the tension of the metal tube-coated optical fiber cable on the tension varying means entry side may be adjusted by the tensioning means provided on the upstream side of the tension varying means.

The extra length can be controlled by adjusting the tension of the optical fiber cable to a constant value and varying the tension of the metal strip, or by adjusting the tension of the metal strip to a constant value and varying the tension of the optical fiber cable. The extra length can be obtained.

Further, a method for manufacturing a metal tube-coated optical fiber cable according to the present invention includes a forming step of forming a pulled metal strip into a metal tube through a forming roller, and welding a butted portion of the formed metal tube with laser light. In a method for manufacturing a metal tube-coated optical fiber cable having a laser welding step of processing a sealed metal tube and an optical fiber introducing step of introducing an optical fiber or an optical fiber bundle into the metal tube, the metal strip on the inlet side of the assembly step is Adjust the tension of the metal tube on the outlet side of the drawing process by changing the tension, and adjust the tension of the optical fiber cable on the inlet side of the optical fiber introducing process to adjust the tension of the optical fiber cable introduced into the metal pipe. In the pulling process, the excess length of the metal tube coated optical fiber cable is controlled by reducing the tension between the metal tube and the optical fiber cable. And it features.

In addition, it is preferable to reduce the tension while pulling the metal tube optical fiber cable with a capstan formed by winding the metal tube coated optical fiber cable a plurality of times.

Further, the tension of the metal tube-coated optical fiber cable may be reduced after applying a tensile force to the metal tube-coated optical fiber cable.

According to the present invention, when the metal tube-coated optical fiber cable is manufactured, the tension of the metal tube-coated optical fiber cable in the preceding stage of the tension varying means is set to the tension of the metal slip processed into the metal tube and the light introduced into the metal tube. Adjusting the fiber cable with tension to give a difference in the tension between the sealed metal tube and the optical fiber cable inside the metal tube, and by reducing this difference in tension with the tension varying means, the sealed metal tube on the inlet side of the tension varying means And a difference in the amount of expansion of the optical fiber cable in the metal tube, and the relative length of the optical fiber cable with respect to the metal tube is arbitrarily adjusted by the difference in the amount of expansion.

Further, by using the capstan in which the metal tube-coated optical fiber cable is wound a plurality of times as the tension varying means, it is possible to easily reduce the tension while pulling the metal tube-coated optical fiber cable.

Further, the control range of the extra length can be expanded by varying the tension of the metal tube on the inlet side of the tension varying means or the tension of the outlet side.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2A and FIG. 2B are cross-sectional views showing a metal pipe in a forming process, FIG. 3A and FIG. 3B, respectively. 3C is a side view showing the forming roller pair of the second assembly, FIG. 4 is a configuration view showing the optical fiber introducing means, FIG. 5 is a configuration view showing the laser welding means, and FIG. 6 is a guide shoe. Figure 7A, side view showing
7B shows tension varying means and tension adjusting means, FIG. 7A is a top view, FIG. 7B is a front view, FIG. 8 is an explanatory view showing a butted portion of a metal pipe, and FIG. 9 is a pipe outer diameter. Fig. 10 is a characteristic diagram showing the relationship between the back bead width, Fig. 10 is a characteristic diagram showing the relationship between the pipe wall thickness and the back bead width, and Figs. 11, 12, and 13 show the relationship between the defocus amount and the welding speed, respectively. The characteristic diagram shown in FIG. 14, FIG. 15, FIG. 16, FIG. 16 and FIG. 17 are explanatory diagrams showing the operation of the extra length control, respectively, and FIG. 18 is a partial configuration diagram showing another arrangement of the optical fiber introducing means.
FIG. 19 is a partial structural view showing another embodiment, FIG. 20 is an explanatory view of a leaf spring mechanism, FIG. 21 is an explanatory view showing a state in which a metal pipe is raised upward, and FIG. 22A is a curved state of an introduction tube. FIG. 22B is an explanatory view showing the positioning mechanism of the introduction tube, and FIG. 23 is an explanatory view showing the positioning state of the metal pipe at the welding position.

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. As shown in the figure, a metal tube coated optical fiber cable manufacturing apparatus includes an assembly 2 including a first assembly 3 and a second assembly 4 each of which forms a metal strip 1 and abuts both ends thereof to form a metal tube. And the optical fiber cable 5 provided in the molded metal tube provided between the first assembly 3 and the second assembly 4.
It has an optical fiber introducing means 6 for introducing a laser beam and a laser welding means 7 provided at the rear stage of the assembly 2.

A measuring unit 8 and a diaphragm unit 9 are connected in series at the subsequent stage of the laser welding unit 7. The tension varying means 11 and the metal tube coated optical fiber cable are provided between the drawing means 9 and the cable winder 10.
It has a pulling means consisting of 12 tension adjusting means 13.

The tension varying means 11, the tension adjusting means 13, and the assembly 2
Tension adjusting means 14 for the metal strip 1 provided in the preceding stage of
And the tension adjusting means 15 of the optical fiber cable 5,
Extra length control means for adjusting the relative length of the optical fiber cable to the metal tube, that is, the extra length is configured.

The first assembly 3 constituting the assembly 2 is composed of a plurality of, for example, five forming roller pairs 31a to 31e, which are continuously arranged in a line. Each of the forming roller pairs 31a to 31e has different forming surfaces in sequence, and the continuously fed metal strip 1 has a substantially U shape having a vertical gap 16 at the top as shown in the sectional view of FIG. 2A. The metal tube 1a is processed.

The second assembly 2 is also composed of a plurality of, for example, five pairs of forming rollers 41a to 41e, which are continuously arranged in a line, and are shown in FIGS. 3A and 3B.
As shown in FIG. 3 and FIG. 3C, the former forming roller pairs 41a to 4a
The upper roller 1d has fins 17 whose width is gradually reduced. Then, engage the gap 16 of the metal tube 1a with the fin 17,
While positioning so that the gap 16 is located at the apex of the metal tube 1a, the gap 16 is made smaller and the final stage forming roller pair 41
The gap 16 is abutted by e, and the metal tube 1b which is almost completely closed by the abutting portion 18 is formed as shown in FIG. 2B.

As shown in the partial cross-sectional view of FIG. 4, the optical fiber introducing means 6 is connected with an introducing tube 61 for guiding the optical fiber cable 5 and introducing it into the metal tube 1b, and a tube connector 62 connected to the introducing tube 61. And an inert gas supply tube 63 connected by an inert gas supply tube connector 62.

The introduction tube 61 is made of a metal having good heat conductivity, such as copper or a copper alloy, and has an outer diameter smaller than the inner diameter of the metal tube 1b. The introduction tube 61 is inserted through the gap 16 of the metal tube 1 between the first assembly 3 and the second assembly 4, the tip thereof passes through the laser welding means 7, and the eddy current flaw detector 81 of the measuring section 8 is inserted.
It is located in front of. The reason why the tip of the introduction tube 61 is inserted in front of the eddy current flaw detector 81 is to prevent the flaw detection accuracy from being adversely affected if the introduction tube 61 is passed to the eddy current flaw detector 81.

However, the introduction tube up to the position where it passes the eddy current flaw detector 81
If the flaw detection result is not adversely affected even through 61, for example, if the diameter of the metal pipe is large and the introduction tube 61 is in contact with the inner wall of the metal pipe on the side opposite to the flaw detection position, this position should be It is also possible to pass it to a point beyond it, for example, just before the diaphragm means 9.

This introduction tube 61 is attached upward before and / or after the laser beam irradiation position of the laser welding means 7, and is a leaf spring mechanism 61 that is elastically contacted with the inner wall surface of the metal tube 1b.
1 (Fig. 20) is attached, or the metal tube 1b is placed at a predetermined distance above the laser beam irradiation position and / or after the laser irradiation position, as shown in Fig. 21, or the introduction tube 61 itself. By applying an elastic force downward to
It is arranged so as to come into contact with the inner wall of the metal tube 1b on the side opposite to the irradiation position of the laser light.

The elastic pressure contact between the introduction tube 61 and the inner wall of the metal tube 1b is, for example, as shown in FIG. 22, due to the elasticity of the introduction tube 61 itself, the introduction tube 61 resists the property of originally stretching. By bending from state I to state II (FIG. (A)), contacting the inner wall of the metal tube 1b in state II (FIG. (B)), and fixing the optical fiber introducing means 6 at an appropriate position. It can be easily realized by maintaining the curved state. At this time, a positioning mechanism 612 such as a spring mechanism may be added to the optical fiber introducing means 6 if necessary.

Further, when the metal tube 1b is arranged at the upper position by a certain distance in front of the laser light irradiation position, the positioning portion 71 described later is finely adjusted. on the other hand. When the metal tube 1b is arranged above the laser beam irradiation position by a certain distance, the support roll stand 82 described later is finely adjusted.

The laser welding means 7, as shown in the configuration diagram of FIG.
Positioning part 71 for positioning the metal tube 1b and laser welding part 72
Consists of

The positioning part 71 is, for example, two sets of guide shoes 73, 74.
And a CCD seam monitor installed between the guide shoes 73 and 74
It has a micrometer 76 for finely adjusting the positions of 75 and the guide shoes 73, 74 in the vertical and horizontal directions.

As shown in the side view of FIG. 6, the guide shoes 73, 74 are composed of an upper shoe 73a (74a) and a lower shoe 73b (74b), and the upper shoe 73a (74a) is a flat surface that contacts the metal tube 1b. The lower shoe 73b (74b) has, for example, a V-shaped groove that engages with the metal tube 1b, and is biased upward by a spring.

The laser welded portion 72 has a laser irradiation means 77 and a gas sealing means 78 for sealing the welding position of the metal tube 1b with an inert gas such as argon gas.

The laser irradiation means 77 is connected to, for example, a carbon dioxide gas laser device, guides and focuses laser light through an optical system, and irradiates the surface of the metal tube 1b at an angle of about 90 degrees. The focal point of the emitted laser light is adjusted so as to be connected below the abutting portion 18 of the metal 1b, that is, inside the metal tube 1b.

The measuring unit 8 provided at the latter stage of the laser welding means 7 includes a support roll stand 82, a speedometer 83 and an eddy current flaw detector 81.
Check the welding condition.

The squeezing means 9 is composed of a roller die, and squeezes the welded and sealed metal tube 1c to a predetermined diameter to make a thin metal tube 1d corresponding to the outer diameter of the optical fiber cable 5.

The tension varying means 11 provided on the exit side of the diaphragm means 9
As shown in FIGS. 7A and 7B, for example, a pair of rolls 11a, 11
It consists of a capstan with b. The surface of one roll 11a is formed smooth, the plurality of grooves is formed on the surface of the other roll 11b, and the metal tube 1d is wound multiple times without overlapping. Further, the tension adjusting means 13 is also a pair of rolls 13.
It is composed of a dancer roll stand having a and 13b, and by moving the position of one roll 13b in the direction of the arrow to change the distance between the rolls 13a and 13b, the metal tube coated optical fiber cable 12 on the exit side of the capstan 11 is formed. Adjust the tension of.

Further, tension adjusting means 14, 15 for adjusting the tension of the metal strip 1 sent to the assembly 2 and the tension of the optical fiber cable 5 sent to the optical fiber introducing port of the introducing tube 61.
Each consists of a dancer stand. The dancer stands 14 and 15 change the tension by moving the weights on the pulleys 14a and 15a that engage with the metal strip 1 and the optical fiber cable 5.

Next, the operation of manufacturing the metal tube-coated optical fiber cable 12 by the manufacturing apparatus configured as described above will be described according to the manufacturing process.

(1) Forming Step The metal strip 1 is continuously supplied to the assembly 2 while the metal strip is adjusted to a predetermined tension by the dancer stand 14. The first assembly 3 of the assembly 2 forms the fed metal strip 1 into a metal tube 1a having a longitudinal gap 16 at the top. This metal tube 1a is sent to the second assembly 4 and the gap 16
While sequentially engaging the fins 17 of the forming roller pairs 41a, 41 of the second assembly 4 with the gap 16 sandwiched therebetween, the forming roller pair 41e at the final stage abuts the gap 16, and the abutting portion 18 completely closes. The formed metal tube 1b is molded. In the abutting portion 18 after passing the final forming roller 41e, a practical problem, a minute gap 18a is generated as described later, but the interval of the gap 18a varies from the forming roller 41e to immediately before the laser light irradiation position. It was confirmed by a CCD monitor (not shown) provided separately that there was not.

(2) Optical fiber cable insertion step On the other hand, the optical fiber cable 5 adjusted to a predetermined tension by the dancer stand 15 is inserted from the gap 16 of the metal tube 1a between the first assembly 3 and the second assembly 4. It is continuously supplied through the introducing tube 61. At the same time, argon gas is supplied from the inert gas supply tube 63 connected to the introduction tube 61 and sent into the introduction tube 61.

(3) Laser Welding Step The metal tube 1b inserted in the introduction tube 61 is sent to the laser welding means 7. Since the metal tube 1b sent to the laser welding means 7 is positioned by the fins 17 of the forming roller pair 41a, 41b, the abutting portion 18 should be perfectly aligned with the position of the laser light emitted from the laser irradiation means 77. You can

Metal tube 1b sent to the positioning part 71 of the laser welding means 7
Is guided by engaging with the grooves of the guide shoes 73, 74. Therefore, it is possible to prevent lateral displacement, rotation, and meandering of the metal tube 1b. Observing the position variation of the abutting portion 18 with the CCD monitor 75, it was found that when the guide roller was used, the abutting portion 18
Was moved by ± 100 μm due to twisting, but it was found that it moved only ± 15 μm when the guide shoe was used. Subsequently, the CCD seam monitor 75 detects the position of the butt portion 18 of the metal tube 1b, and depending on the detection result, the micrometer 76 is automatically or manually operated to guide the shoe.
73 and 74 are moved, and fine adjustment is performed so that the abutting portion 18 is at a predetermined position with respect to the focus of the laser light.

Here, the role of the positioning unit 71 will be particularly described.
First, as described above, the guide shoes 73, 74 of the positioning portion 71 prevent the metal tube 1b from rotating and meandering, and the finned rollers 41a to 41d are abutting portions accurately positioned with respect to the laser irradiation position. 18 is guided to the laser irradiation position without causing the metal tube 1b to meander. Further, as described above, it is possible to arrange the metal tube 1b upward by a certain distance before the laser light irradiation position by adjusting the positioning portion 71.
As a result, the introduction tube 61 can be firmly and elastically contacted with the inner wall surface of the metal tube 1b, so that the adverse effect of laser welding can be minimized as described later, and the continuous production operation can be performed for a long time.

Furthermore, as shown in FIG. 23, the support rolls 82a and 82b of the support roll stand 82 and the final forming roll 41e.
With the fulcrum as the fulcrum, the positioning part 71 is arranged above or below the bus line by a certain distance or more (however, within the range of the elastic limit), and the metal pipe 1b has a substantially triangular shape.
Try to compose an edge.

At this time, the support roll stand 82 and the final forming roll
A slight tension is applied to the metal tube 1b between 41e. This means that the positioning portion 71 functions as a means for adjusting the tension of the metal pipes (in particular, 1c and 1d), like the tension adjusting means 14 for the metal strip described later. As a result, the vibration of the metal tube 1b at the laser welding position (marked by X in the figure) is suppressed.

Actually, another CCD monitor (not shown) was placed at a position inclined by 90 ° with respect to the CCD seam monitor 75 and the pass line at the laser irradiation position, and the vertical vibration of the metal tube 1b was observed. As a result, the guide shoe 7 of the positioning unit 71 is
When opened to 3,74 ± 100 to ± 150 μm, metal tube 1b
Vibrates, but when the metal tube 1b is fixed by the guide shoes 73 and 74, it vibrates about ± 20 to ± 30 μm, and in the figure (A)
Alternatively, when the positioning portion 71 is adjusted as shown in (B), ±
It was confirmed that the vibration was about 5 μm.

In consideration of elastic contact of the introduction tube 61 with the inner wall surface of the metal tube 1b, it is preferable to adjust the positioning portion 71 so as to be (A) rather than (B) in the figure.

The adjustment as described above enables advanced welding control and further reduces the adverse effects of welding, which contributes to long-term operation.

In this way, the metal pipe with the position of the abutting portion 18 adjusted
1b is sent to the laser weld 72. The laser welding section 72 irradiates the butt section 18 of the metal tube 1b with a laser beam from the laser irradiating section 77 while supplying the argon gas to the butt section 18 by the gas sealing means 78 to weld the butt section 18. The inner surface of the welded portion is sealed by the argon gas which is flown into the introduction tube 61 and blows out from the tip of the introduction tube 61 and flows backward.

Before and after this laser light irradiation position, the introduction tube 61 that guides the optical fiber cable 5 is arranged so as to elastically contact the inner wall of the metal tube 1b on the side opposite to the laser light irradiation position, and the abutment is performed. Since a gap is provided between the inner surface of the portion 18 and the introduction tube 61, heat can be shielded by the gap and the introduction tube 61, and the influence of heat on the optical fiber cable 5 can be reduced.

Incidentally, when the introduction tube 61 is arranged on the side opposite to the protruding portion of the metal pipe at the laser welding portion, the positioning portion 71 is adjusted so that the metal pipe 1b is installed above the pass line. The above arrangement of 61 can be realized more elastically.

Further, the temperature rise of the optical fiber cable 5 is suppressed as much as possible by cooling the optical fiber cable 5 with the argon gas flowing in the introduction tube 61 and the argon gas flowing backward from the argon gas.

For example, when the introduction tube 61 is at the laser irradiation position,
The temperature in the vicinity of the optical fiber cable 5 which has reached a temperature of 600 ° C. or higher when it is in contact with 18 is about 115 to 135 ° C. by providing the above-mentioned gap, and is lowered to about 100 ° C. by flowing an argon gas. I was able to do it.

Further, the introduction tube 61 is provided by providing the above-mentioned void.
The adverse effect of the grasshoppers deposited on the welding on the welding can be delayed in time, and stable welding can be performed for a long time.

The laser light emitted from the laser irradiation means 77 is adjusted so that the focal point is connected to the inside of the metal tube 1b, so that the power density of the laser light with which the abutting portion 18 is irradiated is prevented from becoming too high. It is possible to perform stable welding.

Further, by tying the focal point inside the metal tube 1b, once the cavity is formed, the laser light reflected by the cavity wall is focused toward the bottom of the cavity to form a deep cavity and melt. The width of the back bead can be reduced while keeping the width almost constant.

In addition, by controlling the irradiation power density with the defocus amount (focus blurring amount) of the laser light irradiated with a constant power within a certain range, and by determining the welding speed according to the defocus amount, that is, the irradiation power density, The bead width can be reduced to suppress the influence of spatter.

The minimum value b _min of the back bead width is determined by the fact that no unwelded part remains in the abutting part 18, and the maximum value b _max of the back bead width is determined by the limit that spatter does not affect even during long-time operation.

At the position of the laser welding means 7, the metal tube 1b is attached to the guide shoe 7
Although being held down by 3,74, a small gap 18a is formed at the abutting portion 18 of the metal tube 1b due to the spring bag at the position of the laser welding portion 72, as shown in FIG. This small gap 1
The spring bag generating 8a is affected by the rigidity of the metal tube 1b, that is, the outer diameter d of the formed metal tube 1b. For example,
Power is 400 (W) when the metal tube 1b made of Fe-based stainless steel with a longitudinal elastic modulus of 18000 (kg / mm ² ) is completely fixed.
The relationship between the outer diameter d (mm) and the back bead width b (μm) when welding was performed by irradiating the minute gap 18a with FIG. 9 shows b as the vertical width. In FIG. 9, circles indicate the case where no unwelded portion is generated, and cross marks indicate the case where unwelded portion is generated. Therefore, the straight line A shows a limit at which an unwelded portion does not occur, and the straight line A is b = 10d.

Further, in the actual device, it was found from the observation of the CCD seam monitor 75 that relative vibration of about ± 5 (μm) occurs between the laser beam and the minute gap 18a due to minute vibration of the device.

Therefore, the minimum width b _{min of the} back bead is 10d ± 5 (μm). For example, when the outer diameter of the metal tube 1b is 1 (mm), the minimum width b _min of the back bead is 20 (μm).

In addition, the minimum width b _min = 10d ± 5 of the back bead is a metal tube made of Fe-based stainless steel having a longitudinal elastic modulus of 18000 (kg / mm ² ).
The case of using b was explained, but the longitudinal elastic modulus is 18000.
Even when (kg / mm ² ) Fe-based stainless steel or Ni-based alloy is used, by making the back bead width larger than the minimum width b _min , good welding can be performed without any unwelded portion.

Further, the limit of the influence of spatter even after long-term operation is determined by the shape of the fusion zone. So the power is 40
When the relationship between the tube wall thickness t (mm) and the back bead width b (μm) when welding was performed by irradiating the minute gap 18a with a laser beam of 0 (w), the result was investigated, and the tube wall thickness t was taken as the lateral width. , Back bead width b
The vertical axis is shown in FIG. In FIG. 10, circles have no effect of spatter, and when welding can be performed continuously for a long time, for example, 10 hours, spatters are generated on the crosses and welding cannot be performed for a long time. Indicate the case. In addition, the above 10 hours is a time corresponding to the maintenance timing of the actual operation, and does not limit the limit time when there is no influence of spatter.

Therefore, the straight line B shows the limit that there is no influence of spatter even after long-term operation, and this straight line is b = 1000 (t / t
2) Therefore, when the pipe wall thickness t is 0.1 (mm),
Allowable amount of back bead width b _min is 50 (μm).

Thus, for example, a laser beam with a power of 400 (W) is used, and the metal tube 1b has a wall thickness of 0.1 (mm) and an outer diameter of 1 (mm).
In this case, by controlling the width b of the back bead to 20 to 50 (μm) and performing welding, it is possible to suppress the influence of spatter even when operating for a long time and continuously perform welding without welding defects.

In order to keep the back bead width b within a certain range,
It is necessary to control the irradiation power density by defocusing (defocusing) the laser light applied to the abutting portion 18 according to the size of the metal tube 1b.

Further, the welding speed is determined by the focused diameter of the laser light, that is, the defocus amount and the overlap ratio.

Therefore, by changing the size of the metal tube 1b, the above minimum value b _min ≧ 1
0d ± 5 (μm) condition and maximum back bead width b _min ≦ 1
The welding speed V is plotted on the horizontal axis when the results of investigations for the case of satisfying the conditions of 000 (t / 2) and the case of not satisfying these conditions
(M / min), and the vertical axis shows the defocus amount F (mm), which is shown in FIG. 11, FIG. 12 and FIG. Figure 11 shows a metal tube
When the outer diameter d of 1b is 3.5 (mm) and the wall thickness t is 0.2 (mm),
FIG. 12 shows that the outer diameter d of the metal tube 1b is 2.0 (mm) and the wall thickness t is 0.1.
In the case of 5 (mm), Fig. 12 shows that the outer diameter d of the metal tube 1b is 1.0 (m
m) and the tube wall thickness t is 0.1 (mm). In each figure, a circle indicates a case where the above condition is satisfied, and a cross indicates a case where the above condition is not satisfied, and the limit is represented by curves A and B. Then, the minimum value of the proper back bead width b _min
= 10d ± 5 (μm), and the curve B represents the optimum back bead width maximum value b _min = 1000 (t / 2).

As shown in FIG. 11, the outer diameter d of the metal tube 1b is 3.5 (m
m) and the tube wall thickness t is 0.2 (mm), the defocus amount F
The maximum allowable range is from F = 0.85 (mm) to F = 1.45 (mm). Therefore, the defocus amount is set in this range, and by setting the welding speed V to 4 (m / min) and welding, the back bead width b is suppressed to a predetermined range of 40 to 100 (μm), Welding can be performed for a long time without being affected by spatter.

Similarly, the outer diameter d of the metal pipe 1b is 0.2 (mm) and the pipe wall thickness t is
When 0.15 (mm), defocus amount F is 0.8 to 1.3
(Mm) range, welding speed V is set to 6 (m / min) and welding is performed, and the outer diameter d1.0 (mm) of the metal pipe 1b and the pipe wall thickness t are 0.1 (mm). In this case, defocus amount F is 0.7 to 1.1
(Mm), the welding speed V is set to 10 (m / min) and welding is performed, so that good welding can be continuously performed. It should be noted that the size of the minute gap 18a of the abutting portion 18 of the metal tube 1b should fluctuate slightly depending on the extra length control condition and the setting method of the positioning portion 71 (FIGS. 23A and 23B) which are described separately. For example, as shown in FIG. 23A, the size of the minute gap 18a increases, and as in FIG. 23B, the size tends to decrease.

However, in reality, it has been found that, within the range of the measurement mesh in the present application, the influence of the variation of the minute gap 18a as described above hardly influences the welding result.

(4) Measurement and drawing process The metal pipe 1c thus welded at the butt portion 18 and sealed is sent to the measurement portion 8. In the measuring unit 8, the metal pipe 1c is supported by the support roll stand 82, the passing speed, that is, the welding speed V is measured by the speedometer 83, and the eddy current flaw detector 81 inspects the welding state.

The metal tube 1c that has passed through the eddy current flaw detector 81 is reduced in diameter by the diaphragm means 9 to a predetermined diameter corresponding to the outer diameter of the built-in optical fiber cable 5, and becomes the metal tube-coated optical fiber cable 12.
When the diameter of the metal tube 1c is reduced by the throttle means 9, the metal tube 1c
Since only one introduction tube 61 is inserted up to immediately before the eddy current flaw detector 81, the metal tube 1c can be made thin and the diameter can be easily reduced.

(5) Towing / Winding Step The metal tube-coated optical fiber cable 12 whose diameter has been reduced by the drawing means 9 passes through the tension varying means 11 and the tension adjusting means 13 and is wound up by the cable winder 10.

When the optical fiber cable 12 covered with the metal tube is wound, the metal tube 1d and the optical fiber cable 5 which are sealed and reduced in diameter are wound.
Must be engaged. Therefore, prior to continuous operation, the welded and sealed metal tube 1d is manually wound around the capstans 11a and 11b of the tension varying means 11 a predetermined number of times and then pulled, and the tip thereof is passed through the tension adjusting means 13 to wind the cable winder. Install on 10. In this state, the tip of the optical fiber cable 5 is passed to the front of the capstan 11a, and the metal tube 1d is crushed at this position to engage the optical fiber cable 5 with the inside of the metal tube 1d. Then capstan 11
By winding the metal tube 1d while driving the
At the same time, the optical fiber cable 5 is pulled out from the introduction tube 61, and the metal tube-coated optical fiber cable 12 is wound up.

(6) Extra length control process This metal tube coated optical fiber cable 12 is capstan
When wound around 11a, 11b and pulled, the tension acts due to the frictional force between the metal tube 1d of the metal tube-coated optical fiber cable 12 and the capstans 11a, 11b. Since this frictional force is large at the beginning of winding and gradually decreases thereafter, the tension is also large at the beginning of winding and gradually decreases according to the number of windings. And metal tube
Elongation corresponding to this tension occurs in the 1d winding part.

For example, during normal operation, a stainless steel strip 1 with a width of 4 mm and a thickness of 0.1 (mm) is used, and a metal tube with an outer diameter of 1.3 (mm) 1
After processing to c and then narrowing it to a metal tube 1d with an outer diameter of 1.0 (mm), use the tension adjusting means 14 so that the tension of the metal tube 1c at the entrance side of the capstan 11a will be about 20 (kg f). When the tension of the metal strip 1 is adjusted, this tension causes the metal tube 1d
The + 0.30% elongation occurs. At this time, for example, the outer diameter is
The tension of the 125 (μm) optical fiber cable 5 is adjusted by the tension adjusting means 15, and about 25 (gf) at the entrance side of the capstan 11a.
When the tension is applied, the elongation of + 0.03% occurs.

The result of examining the elongation of the metal tube 1d and the optical fiber cable 5 with respect to the number of windings of the metal tube 1d on the capstans 11a and 11b is taken. The horizontal axis shows the number of windings around the capstans 11a and 11b, and the vertical axis shows. Shows the elongation (%) of the metal tube 1d as shown in FIG. In FIG. 14, a curve E shows a change characteristic of the elongation rate of the metal tube 1d, and a curve F shows a change characteristic of the elongation rate of the optical fiber cable 5. As shown by the curve E, when the metal tube 1d is wound around the capstans 11a and 11b six times, the elongation when the metal tube 1d is sent to the tension adjusting means 13 is finally extremely small. Further, as shown by the curve F, the elongation of the optical fiber cable 5 becomes almost zero when it is wound once and a half times.

In this way, when the optical fiber cable 5 stretches to zero after one and a half turns, the metal tube 1d has a stretch of + 0.19%. Then, the metal tube 1d is attached to the capstans 11a and 11b.
Immediately after the winding, the tension of the metal tube 1d becomes almost zero, and the elongation of the metal tube 1d also becomes almost zero. That is, after winding 6 times, the metal tube 1d is
It will shrink by 0.19%. On the other hand, the tension of the optical fiber cable 5 is almost zero after the number of windings is one and a half times,
After that, there is no change in elongation and the length does not change. Therefore, the optical fiber cable 5 becomes 0.19% longer than the metal tube 1d when wound six times.

On the other hand, the metal tube 1d wound around the capstans 11a and 11b
And the optical fiber cable 5 that engages with the inner wall of the metal tube 1d has a different winding diameter. Therefore, for example, when the capstans 11a and 11b have a diameter of about 500 mm, the optical fiber cable 5 has an elongation amount equivalent to + 0.09% with respect to the metal tube 1d. This elongation amount of 0.09% is offset by the above-mentioned 0.19%, and as a result, the optical fiber cable 5 becomes 0.10% longer than the metal tube 1d.

Next, the tension on the entrance side of the capstan 11a of the metal tube 1d is set to the same state as in the case of FIG. 14, and the tension adjusting means 15
Change the tension of the optical fiber cable 5 with capstan 11
An example of the change characteristics of the elongation of the optical fiber cable 5 when the tension on the entry side of a is increased is shown by the curve F1 in FIG. In this case, the optical fiber cable 5 capstan 11a,
The tension is almost zero when wound around 11b three and a half times. On the other hand, the elongation of the metal tube 1d is three and a half times when wound.
0.09%. When the elongation 0.09% of the metal tube 1d and the elongation 0.09% of the optical fiber cable 5 due to the winding diameter difference are offset, the elongation of the metal tube 1d and the optical fiber cable 5 become the same, that is, the difference between the two lengths, that is, The extra length is 0%.

Contrary to the case of FIG. 15, the tension of the metal strip 1 is applied by the tension adjusting means 14 without changing the tension on the entrance side of the capstan 11a of the optical fiber cable 5, and the capstan 11a of the metal tube 1d is moved. When the tension on the entry side is increased,
The change characteristic of the elongation of the metal tube 1d is shown by the curve E1 in FIG.

In addition, the tension on the entrance side of the capstan 11a of the metal tube 1d is exactly the same as in the case of FIG.
Fig. 16 shows the change characteristics of the elongation of the metal tube 1d when the tension of the metal tube 1d on the exit side of the capstans 11a and 11b is increased by
Shown in E2. A case where the tension on the capstan 11a, 11b entrance side and exit side of the metal tube 1d is increased is shown by a curve E3 in FIG.

In this way, by increasing either or both of the tensions of the capstans 11a and 11b of the metal tube 1d on the inlet side and the outlet side by a predetermined value, the length of the optical fiber cable 5 is increased.
It can be made longer than the length of 1d by a desired amount. For example, in the case of the curve E3, the metal tube 1d is attached to the capstan 11
When wrapped around a and 11b once and a half, the elongation of metal tube 1d is +
This is 0.26%, and even if offsetting 0.09% of the elongation due to the winding diameter of the optical fiber cable 5, the optical fiber cable 5 can be made 0.17% longer than the metal tube 1d on the capstan exit side.

Next, when the tension on the capstan entry side of the optical fiber cable 5 is made higher than in the case shown in FIG. 15 and the change characteristic of the elongation of the optical fiber cable 5 is shown by the curve F2 in FIG. The length of the fiber cable 5 can be made shorter than the length of the metal tube 1d. In this case,
The elongation of the optical fiber cable 5 becomes zero when it is wound five times, and the elongation of the metal tube 1d at this time is + 0.04%.
This elongation + 0.04% is the winding difference of the optical fiber cable 5.
This is offset by 09%, and as a result, the optical fiber cable 5 can be made 0.05% shorter than the metal tube 1d.

In this way, multiple times metal tube coated optical fiber cable 12
The capstans 11a and 11b around which the cable is wound, the tension adjusting means 14 of the metal strip 1, the tension adjusting means 15 of the optical fiber cable 5, and, if necessary, the capstans 11a and 11b.
The length of the optical fiber cable 5 with respect to the metal tube 1d can be arbitrarily adjusted by comprehensively adjusting the tension adjusting means 13 on the output side of the. The tension adjusting means 14 for the metal strip 1 is adjusted by adjusting the positioning portion 71.
Similarly, by adjusting the tension of the metal tubes 1c and 1d, the extra length control can be adjusted with higher accuracy. In this case, the function of the extra length control of the positioning portion 71 is the tension adjusting means 14 of the metal strip 1.
Since it is the same as the surplus length control function by, it is not mentioned here.

In the above example, the metal tube 1d has an outer diameter of 1.08 (mm) and a thickness of 0.1 (m
m), the extra length control when the optical fiber cable 5 has an outer diameter of 0.125 (μm) was explained, but the extra length is 0% by changing the outer diameter and thickness of the metal tube 1d and the outer diameter of the optical fiber cable 5. Table 1 shows the elongation (%) of the metal tube 1d and the elongation (%) of the optical fiber cable on the entrance side of the capstan 11 when the above condition occurs.

As shown in Table 1, even if the metal tube 1d having an arbitrary size and the optical fiber cable 5 are used, the extra length control can be performed at a predetermined extra length ratio.

In addition, although the case where argon gas was used as an inert gas was demonstrated in the said Example, the same effect can be produced when nitrogen gas is used.

In addition, the above-mentioned example explained the case where the gel was not introduced into the metal tube to be coated, but when introducing the gel,
By supplying the gel from the inert gas supply tube 63 of the optical fiber cable introducing means 6, the gel can be introduced into the metal pipe 1d using the single introduction tube 61.

In this case, it suffices to flow the inert gas or gel at a pressure such that the optical fiber cable 5 does not receive a tensile force due to the flow of the inert gas or gel. This is because, in fact, the introduction of the optical fiber cable 5 and the control of the extra length can be achieved as desired without flowing an inert gas or gel through the optical fiber cable introduction means 6.

In the above embodiment, the case where the optical fiber cable introducing means 6 is provided between the first assembly 3 and the second assembly 4 of the assembly 2 has been described. As shown in FIG. 18, the introduction tube 61 may be provided in the front stage of the first assembly 3 and inserted from the front of the forming roller pair 31a in the first stage.

Further, in the above-mentioned embodiment, the pulling means consisting of the capstans 11a and 11b of the tension varying means 11 and the tension adjusting means 13 is provided directly after the diaphragm means 9, and the metal tube coated optical fiber cable 12 is provided.
While pulling the capstans 11a and 11b, the tension of the metal tubes 1d on the inlet side and the outlet side and the tension of the optical fiber cable 5 on the inlet side of the capstans 11a and 11b and the tension adjusting means 14,
The case where the excess length is controlled by adjusting with 15, 13 has been explained. However, as shown in FIG.
A means 19 for pulling the metal pipe 1d may be provided in front of a and 11b so that the tension of the metal pipe 1d on the capstan entry side can be arbitrarily changed.

As the pulling means 19, for example, an endless track type capstan is used, and by pulling the metal pipe 1d while sandwiching the metal pipe 1d, the metal pipe 1d can be pulled with a tension required in the molding schedule. And by adjusting the feed rate of the endless track type capstan,
The tension of the metal tube 1d sent to 11a can be controlled arbitrarily.

For example, when the length of the optical fiber cable 5 is made shorter than the length of the metal tube 1d, the tension of the metal tube 1d on the input side of the capstan 11a cannot be made too small in the example of FIG. 17 due to the molding schedule. In addition, although the input side tension is increased in the optical fiber cable 5, it is not preferable to increase the tension of the optical fiber cable too much.
Therefore, by lowering the tension on the entrance side of the capstan 11a of the metal tube 1d by the pulling means 19, the same action as the tension of the optical fiber cable 5 can be relatively increased, and an unreasonable force is applied to the optical fiber cable 5. The extra length can be controlled without adding.

When the optical fiber cable 5 is manufactured and then subjected to secondary processing in a subsequent step, it may deviate from the target extra length value, and in this case also, extra length control becomes necessary. In such a case, it is possible to obtain an optical fiber cable having an appropriate extra length after the secondary processing by previously performing the extra length control in consideration of the deviation of the extra length value.

Further, in each of the above-described embodiments, the case where one optical fiber cable is introduced into the metal pipe has been described, but an optical fiber bundle including a plurality of optical fibers can be similarly introduced.

As described above, the present invention introduces the tension of the metal-coated optical fiber cable in the preceding stage of the tension varying means into the tension of the metal strip to be processed into the metal tube and the metal tube when manufacturing the metal-tube-coated optical fiber cable. The tension of the optical fiber cable to be adjusted is adjusted to give a difference in tension between the sealed metal tube and the optical fiber cable in the metal tube, and the difference in the tension is reduced by the tension varying means. The expansion amount of the optical fiber cable inside the sealed metal tube and the metal tube is given, and the relative length of the optical fiber cable to the metal tube can be adjusted arbitrarily according to the usage conditions by the difference in the expansion amount. The coated optical fiber cable can be stably installed and used.

Also, by using a capstan in which the metal tube-coated optical fiber cable is wound multiple times as the tension varying means, the tension of the sealed metal tube and the optical fiber cable inside the metal tube is pulled while pulling the metal tube-coated optical fiber cable. Can be arbitrarily reduced, and the surplus length of the metal tube-coated optical fiber cable can be precisely controlled.

Furthermore, by freely varying the tension of the metal tube on the tension varying means inlet side by the tensioning means, the extra length control can be stably performed and the control range of the extra length can be expanded.

Claims (11)

(57) [Claims] 1. A forming means for abutting both ends of a drawn metal strip to form a metal tube, an optical fiber introducing means for introducing an optical fiber or an optical fiber bundle into the metal tube, and controlling a surplus length of the optical fiber with respect to the metal tube. In the manufacturing apparatus for a metal tube-covered optical fiber cable having extra length adjusting means, the extra length adjusting means winds the metal tube and the optical fiber or the optical fiber bundle a plurality of times to gradually reduce the tensions thereof, and A rotary drum arranged downstream of the means, and a fiber tension adjusting means arranged upstream of the optical fiber introducing means for adjusting the tension of the optical fiber or the optical fiber bundle, and generated by winding around the rotary drum. Considering the difference in length between the metal tube and the optical fiber or optical fiber bundle, An apparatus for producing an optical fiber cable coated with a metal tube, characterized in that the tension of the metal tube and the tension of the optical fiber or the optical fiber bundle are relatively adjusted. 2. The apparatus for manufacturing a metal tube-covered optical fiber cable according to claim 1, wherein the rotating drum includes the metal tube and a capstan for pulling the optical fiber or the optical fiber bundle. 3. The apparatus for producing a metal tube-covered optical fiber cable according to claim 1, further comprising means for adjusting the tension of the metal tube on the downstream side of the rotary drum. 4. The apparatus for producing a metal tube-coated optical fiber cable according to claim 1, further comprising means for adjusting the tension of the metal strip on the upstream side of the molding means. 5. Position welding means for positioning the metal pipe at a position above or below the pass line of the metal pipe is provided downstream of the forming means and upstream of the rotary drum. The manufacturing apparatus for a metal tube-coated optical fiber cable according to claim 1, 2, 3, or 4. 6. An endless track type capstan is provided on the upstream side of the rotating drum.
3. The apparatus for producing a metal tube-coated optical fiber cable described in 3, 4, or 5. 7. A molding step of abutting both ends of a pulled metal strip to form a metal tube, an optical fiber introducing step of introducing an optical fiber or an optical fiber bundle into the metal tube, and controlling a surplus length of the optical fiber with respect to the metal tube. In the method for producing a metal tube-covered optical fiber cable having a surplus length adjusting step, the surplus length adjusting step is a rotating drum for winding the metal tube and the optical fiber or the optical fiber bundle a plurality of times and gradually reducing the tension thereof. A variable step and a fiber tension adjusting step of adjusting the tension of the optical fiber or the optical fiber bundle are included, and in consideration of the difference in length between the metal tube and the optical fiber or the optical fiber bundle, which is caused by winding on the rotating drum. , The tension of the metal pipe and the tension of the optical fiber or optical fiber bundle are A method for manufacturing a metal tube-covered optical fiber cable, which is characterized in that the adjustment is carried out mechanically. 8. The method for manufacturing an optical fiber cable coated with a metal tube according to claim 7, wherein the extra length adjusting step adjusts the tension of the metal tube to a constant value and changes the tension of the optical fiber or the optical fiber bundle. . 9. The method for producing a metal tube-covered optical fiber cable according to claim 7, wherein the tension of the metal tube is adjusted on the downstream side of the rotary drum. 10. The method for producing an optical fiber cable covered with a metal tube according to claim 7, wherein the tension of the metal strip is adjusted. 11. The tension of the metal pipe is finely adjusted by positioning the metal pipe at a position above or below the pass line.
Alternatively, the method for producing an optical fiber cable coated with a metal tube according to item 10.