JP6328528B2 - Optical fiber cable manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing an optical fiber cable. In particular, the present invention relates to a method of manufacturing an optical fiber cable twisted alternately in the S direction and the Z direction.

  In the FTTH (Fiber To The Home) network, an optical drop cable is widely used as an overhead wiring from a closure to a subscriber's house.

  A typical optical drop cable 1 is shown in FIG. 1A is a perspective view of the optical drop cable 1, and FIG. 1B is a cross-sectional view of the optical drop cable 1. As shown in FIG. 1, the optical drop cable 1 includes an optical fiber core wire 11, a support wire 12, a strength member 13, and a sheath 14 covering these.

  The support wire 12 is a single linear member disposed on one side of the optical fiber core wire 11 along the optical fiber core wire 11, and is, for example, a steel wire. The tensile body 13 is two linear members disposed on both sides of the optical fiber core wire 11 along the optical fiber core wire 11, and is, for example, an AFRP (aramid fiber reinforced plastic) wire. The sheath 14 includes a prismatic element portion 14a in which the optical fiber core wire 11 and the strength member 13 are embedded, a columnar support portion 14b in which the support wire 12 is embedded, and a neck portion that connects the element portion 14a and the support portion 14b. This is a resin molded body made of 14c.

  Such an optical drop cable 1 may cause self-excited vibration under strong wind when it is suspended in the air. Non-Patent Document 1 can suppress such self-excited vibration by alternately twisting the optical drop cable 1 in the S direction and the Z direction (hereinafter abbreviated as “SZ twist”). It is shown.

  The optical drop cable 1 twisted by SZ is shown in FIG. 2A is a plan view of the optical drop cable 1 twisted by SZ, and FIG. 2B is a cross-sectional view of the optical drop cable 1 twisted by SZ.

  The optical drop cable 1 shown in FIG. 2 is twisted by 90 ° in the S direction (clockwise when viewed from the z-axis positive direction) in the section from the AA ′ section to the BB ′ section, and the section from the BB ′ section to the CC ′ section. In FIG. 5, the wire is further twisted by 90 ° in the S direction. That is, it is twisted 180 ° in the S direction in the section from the AA ′ section to the CC ′ section. Further, the optical drop cable 1 shown in FIG. 2 is twisted 90 ° in the Z direction (counterclockwise when viewed from the z-axis positive direction) in the section from the CC ′ section to the DD ′ section, and from the DD ′ section to the EE ′ section. Further, it is twisted by 90 ° in the Z direction in the section up to. That is, it is twisted 180 ° in the Z direction in the section from the CC ′ section to the EE ′ section.

D. Sakakibara et al., "Low Wind Pressure Aerial Cable Research", International Wire & Cable Symposium, Proceedings of the 57th IWCS, 2008, p.46-52

  The optical drop cable 1 is manufactured by extruding a sheath 14 around the optical fiber core wire 11, the support wire 12, and the strength member 13. At this time, an extruding head used for extruding the sheath 14 is alternately rotated clockwise / counterclockwise around the support wire 12 as a rotation axis, and a feeding device used for feeding the optical fiber core wire 11 and the tensile member 13 is provided. If the support wire 12 is alternately turned clockwise / counterclockwise about the turning axis, the SZ twisted optical drop cable 1 can be manufactured.

  However, when manufacturing the optical drop cable 1 by such a method, a mechanism for rotating the extrusion head, a mechanism for rotating the delivery device, and the like are required. For this reason, an increase in manufacturing cost due to the complexity of the manufacturing apparatus is inevitable.

  The present invention has been made in view of the above problems, and an object thereof is to realize a manufacturing method capable of manufacturing an SZ twisted optical fiber cable, such as an SZ twisted optical drop cable, easily and inexpensively. It is in.

  In order to solve the above-described problems, a manufacturing method according to the present invention includes an optical fiber core, a support line along the optical fiber core, and a sheath covering the optical fiber core and the support line. In the optical fiber cable manufacturing method, a twisting step of alternately twisting the support wire in the S direction and the Z direction, and the sheath is extruded around the optical fiber core wire and the support wire in the twisted state. A molding step for molding, and a curing step for curing the sheath of the optical fiber cable that has transitioned from a non-twisted state to a twisted state, with a transition from a twisted state to a non-twisted state of the support wire, It is characterized by including.

  According to the above configuration, the S head and the Z direction are alternately twisted without rotating the extrusion head for extruding the sheath or turning the delivery device used for delivery of the optical fiber core wire. A twisted optical fiber cable can be manufactured. This makes it possible to easily and inexpensively manufacture an optical fiber cable twisted alternately in the S direction and the Z direction.

  In the manufacturing method according to the present invention, the support wire is preferably a steel wire.

  According to said structure, the transition from the twisted state of the said support wire to a non-twisted state arises reliably, As a result, the transition from the non-twisted state of the said optical fiber cable to a twisted state is ensured. Arise. Therefore, it becomes possible to manufacture a sufficiently twisted optical fiber cable.

  The steel wire is an example of a linear member that is elastic with respect to twisting. Even when the linear member other than the steel wire is used as the support wire, the same effect as that when the steel wire is used as the support wire is obtained as long as the linear member is elastic with respect to twisting.

  In the manufacturing method according to the present invention, the twist amount for twisting the support wire in the twisting step is 1.2 times to 1.4 times the twist amount of the optical fiber cable to be manufactured. It is preferable that there is.

  According to said structure, it becomes possible to manufacture the optical fiber cable which has a desired twist amount.

  In the manufacturing method according to the present invention, the optical fiber cable is an optical drop cable, and the sheath includes a prismatic element portion in which the optical fiber core wire is embedded, and a columnar support portion in which the support wire is embedded. And a neck portion that connects the element portion and the support portion.

  According to the above configuration, it is possible to manufacture an optical drop cable in which self-excited vibration hardly occurs even when the wind is strong.

  According to the present invention, an optical fiber cable twisted alternately in the S direction and the Z direction can be easily and inexpensively manufactured.

It is a figure which illustrates an optical drop cable. (A) is a perspective view of an optical drop cable, (b) is sectional drawing of an optical drop cable. It is a figure which illustrates the optical drop cable twisted by SZ. (A) is a top view of the optical drop cable twisted by SZ, (b) is a sectional view of the optical drop cable twisted by SZ. It is a block diagram which shows the structure of the manufacturing apparatus which manufactures the optical drop cable shown in FIG. It is a flowchart which shows the flow of the manufacturing method which manufactures the optical drop cable shown in FIG. 2 using the manufacturing apparatus shown in FIG. It is sectional drawing which shows the cross section of the optical drop cable (Before extrusion of a sheath is carried out, an optical fiber core wire, a support wire, and a tensile strength body) to which each process shown in FIG. 4 was applied. It is sectional drawing which shows the cross section of the optical drop cable to which the twisting process shown in FIG. 4 was applied.

  As an embodiment of the present invention, a manufacturing method for manufacturing the optical drop cable 1 shown in FIG. 2 will be described as follows.

〔manufacturing device〕
First, a manufacturing apparatus 100 for manufacturing the optical drop cable 1 will be described with reference to FIG. 3A is a block diagram illustrating a configuration of the manufacturing apparatus 100, and FIG. 3B is a cross-sectional view of the extrusion head 105 provided in the manufacturing apparatus 100. FIG.

  As shown in FIG. 3, the manufacturing apparatus 100 includes an optical fiber core wire delivery device 101, a support wire delivery device 102, a tensile strength material delivery device 103, a support wire twisting device 104, an extrusion head 105, a cooling water tank 106, and a take-up device 107. , And a winding device 108.

  The optical fiber core wire sending device 101 is a device for sending out the optical fiber core wire 11 wound around a drum. The support wire sending device 102 is a device for sending out the support wire 12 wound around the drum. Further, the tensile body feeder 103 is a device for feeding out the tensile body wound around the drum.

  The support wire twisting device 104 is a device for twisting the support wire 12 sent out from the support wire sending device 102. In the present embodiment, a caterpillar is used as the support wire twisting device 104, and the caterpillar is rotated about the support wire 12 as a rotation axis, whereby the support wire 12 is twisted. In this case, the amount of twisting of the support wire 12 matches the amount of rotation of the support wire twisting device 14 in the support wire twisting device 104, and gradually decreases as the distance from the support wire twisting device 104 increases.

  The extrusion head 105 includes an optical fiber core wire 11 sent out from the optical fiber core wire sending device 101, a strength member 13 sent out from the strength member sending device 103, and a support wire twisted by the support wire twisting device 104. 12 is an apparatus for extruding a sheath 14 around 12. In order to sufficiently increase the twist amount of the support wire 12 in the extrusion head 105 (in other words, to sufficiently reduce the difference from the twist amount of the support wire 12 in the support wire twisting device 104). The head 105 is disposed in the vicinity of the support wire twisting device 104 (for example, a range in which the distance from the support wire twisting device 104 is 50 cm or more and 60 cm or less).

  As shown in FIG. 3B, the extrusion head 105 includes a nipple 105a and a die 105b.

  The nipple 105 a is a truncated cone-shaped jig in which insertion holes 105 a 1 to 105 a 4 for inserting the optical fiber core wire 11, the support wire 12, and the strength member 13 are formed. The die 105b is a cylindrical mold in which an opening 105b1 having the same shape as the cross section of the sheath 14 is formed on one bottom surface. On the other bottom surface of the die 105b, a truncated cone-shaped insertion port 105b2 communicating with the opening 105b1 is formed, and the nipple 105a is inserted into the insertion port 105b2.

  When the thermoplastic fiber is supplied to the gap between the nipple 105a and the die 105b and the optical fiber core wire 11, the support wire 12, and the tensile body 13 are sent out and the optical drop cable 1 is taken out, the cross section becomes the opening 105b. A sheath 14 having the same shape is extruded around the optical fiber core wire 11, the support wire 12, and the strength member 13. The sheath 14 extruded by the extrusion head 105 is cooled and cured in the cooling water tank 106.

  The take-up device 107 is a device for taking out the optical drop cable 1 manufactured by each of the above devices. The winding device 108 is a device for winding the optical drop cable 1 taken up by the drawing device 107 onto a drum.

〔Production method〕
Next, a manufacturing method S100 for manufacturing the optical drop cable 1 using the manufacturing apparatus 100 will be described with reference to FIGS. FIG. 4 is a flowchart showing the flow of the manufacturing method S100. FIG. 5 shows a cross section of the optical drop cable 1 to which each step included in the manufacturing method S100 is applied (before the sheath 14 is extruded, the optical fiber core wire 11, the support wire 12, and the strength member 13). It is sectional drawing shown.

  As shown in FIG. 4, the manufacturing method S100 includes a sending step S101, a twisting step S102, a forming step S103, a curing step S104, a take-up step S105, and a winding step S106.

  The sending step S101 is a step of sending out the optical fiber core wire 11, the support wire 12, and the strength member 13 wound around the drum. The feeding of the optical fiber core wire 11, the support wire 12, and the tensile body 13 in the delivery step S101 is performed using the optical fiber core wire delivery device 101, the support wire delivery device 102, and the tensile body delivery device 103, respectively. .

  If the cross sections of the optical fiber core wire 11, the support wire 12, and the strength member 13 sent out in the sending step S101 are schematically shown, FIG. 5A is obtained.

  The twisting step S102 is a step of twisting the support wire 12 sent out in the sending step S101. The support wire 12 is twisted using the support wire twisting device 104 in the twisting step S102.

  If the cross section of the support wire 12 twisted in the twisting step S102 is schematically shown together with the cross sections of the optical fiber core wire 11 and the strength member 13, FIG. 5B is obtained. The support line 12 shown in FIG. 5B is in a state of being twisted by about 120 ° in the S direction with the state shown in FIG.

  The forming step S103 is a step for extruding the sheath 14 around the optical fiber core wire 11 and the strength member 13 sent out in the sending step S101 and the support wire 12 twisted in the twisting step S102. It is. Extrusion molding of the sheath 14 in the molding step S103 is performed using the extrusion head 105.

  If the cross section of the sheath 14 formed in the forming step S103 is schematically shown along with the cross sections of the optical fiber core wire 11, the support wire 12, and the strength member 13, FIG. 5C is obtained. The support wire 12 shown in FIG. 5C is in a state of being twisted about 90 ° in the S direction, with the state shown in FIG. The twisting direction of the support wire 12 in the forming step S103 is the same as the twisting direction of the support wire 12 in the twisting step S102, but the absolute value of the twisting amount of the support wire 12 in the forming step S103 is the twisting step. Note that it is smaller than the absolute value of the twist amount of the support wire 12 in S12.

  After the forming step S103, the twisting of the support wire 12 is spontaneously eliminated. With the transition of the support wire 12 from the twisted state to the non-twisted state, the optical drop cable 1 spontaneously transitions from the non-twisted state to the twisted state. If the cross section of the optical drop cable 1 which has transitioned to the twisted state is schematically shown, it is as shown in FIG. The optical drop cable 1 shown in FIG. 5D is in a state of being twisted by about 90 ° in the Z direction with the state shown in FIG. The absolute value of the twist amount of the optical drop cable 1 that has transitioned to the twisted state is substantially the same as the absolute value of the twist amount of the support wire 12 in the forming step S103, but the optical drop that has transitioned to the twisted state It should be noted that the twisting direction of the cable 1 is opposite to the twisting direction of the support wire 12 in the forming step S103. The transition from the non-twisted state to the twisted state of the optical drop cable 1 may be completed before the sheath 14 is cured, and needs to be completed before the next step (curing step S104) is started. Absent.

  The curing step S104 is a step of cooling and curing the sheath 14 extruded in the molding step S103. Cooling of the sheath 14 in the curing step S <b> 104 is performed using the cooling water tank 106.

  The taking step S105 is a step of taking the optical drop cable 1 manufactured through the above steps. The taking-off of the optical drop cable 1 in the taking step S <b> 105 is performed using the taking-up device 107.

  The winding step S106 is a step of winding the optical drop cable 1 taken in the taking step S105 onto a drum. The winding of the optical drop cable 1 in the winding step S106 is performed using the winding device 108.

  The support wire twisting device 104 used in the twisting step S102 alternately repeats the S-direction twist and the Z-direction twist with respect to the support wire 12. When manufacturing the optical drop cable 1 in which the pitch of the SZ twist is L, the support wire twisting device 104 is arranged in the S direction with respect to the support wire 12 while the pulling device 107 pulls the optical drop cable 1 by the length L. Twist and Z-direction twist are performed once each. For example, when the optical drop cable 1 shown in FIG. 2 is manufactured, the support wire twisting device 104 shows the support wire 12 in the AA ′ cross section, the BB ′ cross section, the CC ′ cross section, the DD ′ cross section, and the EE ′ cross section. Twist as shown in FIG.

  According to the manufacturing method S100 described above, the SZ twisted optical drop cable 1 is manufactured without rotating the extrusion head 105 or turning the optical fiber core wire delivery device 101 and the tensile strength body delivery device 103. Can do. That is, the SZ twisted optical drop cable can be manufactured easily and inexpensively.

[Relationship between twist amount of support wire and twist amount of optical drop cable]
Next, the correspondence between the twisting amount of the support wire 12 in the twisting step S102 and the twisting amount of the optical drop cable 1 manufactured using the manufacturing method S100 will be described with reference to Table 1. Table 1 shows the amount of twist of the support wire 12 in the twisting step S102 (actual value obtained by measuring the amount of rotation of the support wire twisting device 104) and the optical drop produced using the production method S100. It is a table | surface which shows the correspondence with the twist amount (The measured value obtained by measuring the twist amount of the completed optical drop cable 1) of the cable 1. FIG. In Table 1, a positive twist amount indicates a twist in the S direction, and a negative twist amount indicates a twist in the Z direction.

  The correspondence relationship shown in Table 1 is that the optical fiber core wire 11 is a Φ250 μm single core coated with a glass optical fiber or the like with a UV curable resin, the support wire 12 is a Φ1.2 mm galvanized steel wire, and the tensile strength is This is obtained when AFRP (aramid fiber reinforced plastic) is used as the body 13 and flame-retardant polyolefin is used as the sheath 14.

  As shown in Table 1, the twist amount of the optical drop cable 1 is 70% of the twist amount of the support wire 12 (when the twist amount of the support wire 12 is ± 150 °) or more and 81.25% (support) When the twisting amount of the wire 12 is ± 80 °) or less. From this, it can be seen that the twisting amount of the support wire 12 in the twisting step S102 should be approximately 1.2 to 1.4 times the twisting amount of the optical drop cable 1 to be manufactured.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  For example, in the above-described embodiment, the method for manufacturing the optical drop cable has been described. However, the optical fiber cable that can be manufactured by the manufacturing method according to the present invention is not limited to the optical drop cable. That is, as long as the optical fiber cable includes an optical fiber core wire, a support line along the optical fiber core wire, and a sheath covering the optical fiber core wire and the support wire, the optical fiber cable according to the present invention is similar to the optical drop cable. It can be manufactured by a manufacturing method.

  Here, the optical fiber core wire is not limited to a single core. That is, the optical fiber core may be multi-core, and in the case of multi-core, it may be a tape core or not a tape core. Moreover, a support wire is not limited to a steel wire. Any linear member that is elastic to twisting can be used as a support wire. Moreover, even an optical fiber cable that does not include a tensile body can be manufactured by the manufacturing method according to the present invention.

  The present invention is suitable for manufacturing an optical drop cable used as an overhead wiring from a closure to a subscriber's house, for example.

1 Optical drop cable (optical fiber cable)
DESCRIPTION OF SYMBOLS 11 Optical fiber core wire 12 Support line 13 Strength body 14 Sheath 14a Element part 14b Support part 14c Neck part S100 Manufacturing method of optical drop cable (optical fiber cable) S101 Sending process S102 Twisting process S103 Molding process S104 Curing process S105 Taking-off process S106 Winding process

Claims (2)

In a manufacturing method of an optical fiber cable, a support line along the optical fiber core line, and an optical fiber cable including a sheath that covers the optical fiber core line and the support line,
A twisting step of alternately twisting the support wire in the S direction and the Z direction;
A molding step of extruding the sheath around the optical fiber core wire and the support wire in a twisted state;
A curing step of curing the sheath of the optical fiber cable that has transitioned from the non-twisted state to the twisted state in accordance with the transition from the twisted state to the non-twisted state of the support wire,
The position for performing the molding step is a range in which the distance from the position for performing the twisting step is 50 cm or more and 60 cm or less,
The twist twisting amount of twisting the support line at step Ri twisting amount of 1.2 times to 1.4 times der following the optical fiber cable to be produced,
The support wire is a steel wire,
The support wire has a diameter of 1.2 mm.
The manufacturing method characterized by the above-mentioned. The optical fiber cable is an optical drop cable,
The sheath includes a prismatic element portion in which the optical fiber core wire is embedded, a columnar support portion in which the support wire is embedded, and a neck portion that connects the element portion and the support portion. ,
The process according to claim 1, characterized in that.

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