JP2002174758A - Spacer for optical fiber cable, optical fiber cable using the spacer and method for manufacturing the spacer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a spacer for an optical fiber cable by which a groove inclination of a spiral groove housing an optical fiber is controlled. SOLUTION: A coated high-tensile wire 4 in which a preliminary coating layer is provided in the outer periphery of a high-tensile body is pre-heated by passing through a heating tank 5, thereafter the wire is introduced into an extruder 7 having a rotating die 6 corresponding to the cross section shape of the spacer, the wire is guided to a cooling zone 9 to cool it after rotating, extruding and coating a spacer main body resin layer at prescribed speed, and whereby a PE spacer 10 is obtained. Three stages of ring shaped air nozzles are set up in the cooling zone 9 along the running direction of the spacer 10. Air is almost orthogonally brown out of the nozzles toward the spacer 10 and is brown against the groove bottom of the spacer 10, and the root part of a rib is cooled preferentially more than the middle part. The spacer 10 is specified by nearly 1.5 mm in the minimum rib thickness at the root of the rib demarcating the spiral groove, 11.9 degrees in the advancing angle and nearly 15 degrees in the groove inclination angle α.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for an optical fiber cable, an optical fiber cable using the spacer, and a method of manufacturing the spacer. It is about technology.

[0002]

2. Description of the Related Art In order to reduce the cost and installation cost of optical fiber cables, studies have been made on reducing the diameter, weight, and optical density of the cables. With regard to a polyethylene (PE) optical fiber cable spacer to be housed and carried, the demand for a smaller diameter and a deeper groove is becoming stricter. On the other hand, recent aerial optical fiber cables are beginning to require branching performance after the middle of the optical fiber in addition to increasing the optical density, and in order to respond to this demand, the spiral direction of the optical fiber housing groove is periodically changed. An SZ type optical fiber cable which uses a PE-made spacer (SZ spacer) which is inverted to the above and which accommodates a plurality of tape-shaped optical fibers or single-core optical fibers in each groove has been widely used.

Here, when a rigid optical tape is stored in the SZ spacer, it is necessary to secure a space for the optical tape to be fertile as the dimensions of the storage groove.

Further, the polyethylene resin of the ribs defining the side surfaces of the spiral groove has a three-dimensional molding shrinkage during extrusion molding (the sum of shrinkage due to recrystallization during solidification and volume shrinkage due to a decrease in resin temperature). Occurs.

[0005] Unlike the one-way twist spacer, which has no room for the ribs to shrink in the longitudinal direction when such molding shrinkage occurs, in the case of the SZ spacer, only in the inversion portion, the inversion curve is short-cut. Of the rib can be longitudinally contracted, and as a result, the rib falls down inside the inversion curve.

This phenomenon is promoted when the height of the ribs is high (groove depth is deep). Therefore, in combination with the above-mentioned problem of securing the groove space, it is difficult to make the SZ spacer deeper. It was an inhibiting factor.

[0007] By the way, about this rib fall,
Other than resin molding shrinkage, when extrusion coating from a die,
It is considered that the coating resins may be pulled together by the difference in the conditions for pulling down the resins.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and suppresses the inclination of a groove in an inversion portion of an SZ spiral grooved spacer for an optical fiber cable without deteriorating transmission loss. Another object of the present invention is to realize a deep groove of the SZ spacer.

[0009]

In order to solve the above-mentioned problems, the present invention provides an intermediate coating layer made of a thermoplastic resin having compatibility with polyethylene around a central tensile strength member, and is provided with a periodic coating along a longitudinal direction. A spacer body coating layer having a spiral groove for housing an optical fiber which is reversed in the longitudinal direction, and a polyethylene optical fiber cable spacer provided on the outer periphery of the intermediate coating layer; The minimum rib thickness of the ribs defining the side surface is 1.0 mm or more, the groove depth is 2.0 mm or more, the maximum spiral advance angle is 8 degrees or more, and the groove inclination angle in the spacer section of the inversion portion is 18 degrees or less.

Here, the spiral angle of the present invention will be described. As shown in FIG. 5, the spacer has a plurality of spiral grooves. In the present invention, the entry angle θ of such a spiral groove with respect to the longitudinal axis of the spacer or an axis parallel thereto is defined as a spiral advance angle, and the one with the largest angle is defined as the maximum spiral advance angle. In the optical fiber cable spacer having the above-described configuration, the ribs that define the side surfaces of the spiral groove can have the lowest resin density at a substantially root portion as compared with the resin density at the front end portion and the central portion. . Further, the spacer having the above-described configuration can be formed into an optical fiber cable by storing an optical fiber such as a tape in at least one of the spiral grooves. Further, the present invention provides an optical fiber in which an intermediate coating layer is provided around a central tensile strength member with a thermoplastic resin having compatibility with polyethylene, the direction is periodically reversed along the longitudinal direction, and the longitudinal direction is continuous. The method of manufacturing a spacer for a fiber optic cable in which a spacer body covering layer having a spiral groove for storage is provided on the outer periphery of the intermediate covering layer, after forming the spacer body covering layer, On the other hand, along the running direction of the spacer, a plurality of cooling air nozzles are provided in a multi-stage manner at predetermined intervals, and dry air is supplied from the position spaced apart from the outer periphery of the spacer by a predetermined distance through the air nozzle. It is characterized in that cooling is performed by spraying the outer periphery of the spacer substantially perpendicularly.

[0011] According to the method of manufacturing the optical fiber cable spacer configured as described above, after forming the spacer main body coating layer, the spacer running at a predetermined speed is separated from the spacer running at a predetermined interval along the running direction of the spacer. A plurality of cooling air nozzles are installed in a multi-stage manner, and cooling is performed by blowing dry air substantially perpendicularly to the outer periphery of the spacer from the position at a predetermined distance from the outer periphery of the spacer via the air nozzle.

In such a cooling state, dry air is directly blown onto the bottom of the spiral groove of the spacer,
The root portion of the rib that defines the side surface of the spiral groove is cooled earlier and preferentially than the intermediate portion.

For this reason, the ribs defining the side surfaces of the spiral groove can effectively prevent the inside of the reverse curve from falling down, and the minimum rib thickness of the rib is 1.0 mm or more and the groove depth is 2. It is possible to obtain a spacer whose diameter is reduced to 0 mm or more, the maximum spiral angle is 8 degrees or more, and the groove inclination angle in the cross section of the inversion portion is 18 degrees or less.

When the groove inclination angle becomes 18 degrees or less,
When an optical fiber is housed in a spiral groove to form an optical fiber cable, the transmission loss can be suppressed to be low.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below along with examples. (Example 1) A steel stranded wire obtained by twisting seven steel wires having an outer diameter of 1.4 mm was introduced into a crosshead as a tensile strength member 1, and an ethylene-ethyl aclute copolymer resin ( GA-006: manufactured by Nippon Unicar), pre-coated inner layer 2, linear low-density polyethylene resin (NUCG53)
50: manufactured by Nippon Unicar) as pre-coating outer layer 3 of 200
Co-extrusion coating at ℃ to obtain a coated tensile strength wire 4 having an outer diameter of an ethylene-ethyl aclute copolymer resin layer of φ4.8 mm and an outer diameter of a linear low-density polyethylene resin coating of φ9.7 mm on the outer periphery thereof. .

As shown in FIG. 1, the coated tensile strength wire 4 is passed through a heating tank 5 so that the surface temperature thereof becomes 60 °.
° C, and then introduced into an extruder 7 provided with a rotary die 6 corresponding to the cross-sectional shape of the spacer, and as a resin for forming the spacer main body resin layer 8, MI = 0.03.
(G / 10 min) high-density polyethylene resin (Hiz
ex6600M: manufactured by Mitsui Chemicals, Inc.) was subjected to rotary extrusion coating at a speed of 6 m / min, and then led to a cooling zone 9 for cooling to obtain a PE spacer 10 having an outer diameter of 15.7 mm.

In the cooling zone 10, three ring-shaped air nozzles 11, the details of which are shown in FIG. 2, are provided in three stages along the running direction of the spacer 10 at intervals of 300 mm.

The air nozzle 11 used in the embodiment includes a nozzle support 11a, an annular space 11b provided in the nozzle support 11a, and an inner periphery of the annular space 11b.
A cooling nozzle portion 11c that opens in a slit shape so as to rotate and has a tip opening portion projecting inward in a ring shape, and dry air as a cooling medium is supplied from the outer peripheral side of the annular space portion 11b.

The spacer 10 is inserted through the center of the cooling nozzle 11c, and runs at a predetermined take-up speed in the direction of the arrow. The dry air supplied into the annular space 11b blows out from the cooling nozzle 11c almost perpendicularly (at right angles) to the spacer 10 at a flow rate of 20 m ³ / sec, and flows to the bottom of the spiral groove 12 of the spacer 10. The root portion of the rib 13 that is sprayed and that defines the side surface of the spiral groove 12 is cooled earlier and preferentially than the intermediate portion.

In this case, the amount of dry air blown out from each of the air nozzles 11 arranged in three stages is set to the same condition in the above-described embodiment. It is also possible to reduce or reduce the blowing amount only in the middle stage.

The resin discharge nozzle of the rotary die 6 has a cross-sectional area Sb obtained by subtracting the cross-sectional area St of the coating tension line 4 from the target cross-sectional area Ss of the PE spacer 10.
From the nozzle hole sectional area Sn to the sectional area S of the coated tensile strength wire 4.
The one designed so that the value Sb / Snb divided by the cross-sectional area Snb after subtracting t was 0.95 was used.

The obtained EP spacer 10 has eight spiral grooves 12 on the outer periphery of the spacer main body coating layer 8 as shown in FIG. Each spiral groove 12
The groove depth is 2.8 mm, the groove width is 2.8 mm,
It has a substantially U-shape and is evenly arranged in eight circumferential directions.

These spiral grooves 12 have a reversal pitch of 2
It had a helical structure twisted in an SZ shape at 35 mm, an inversion angle of 360 °, and had a target size and shape, and satisfied various specifications.

The PE spacer 10 has a minimum rib thickness at the root of the rib 13 defining the spiral groove 12 of about 1.
5 mm, and the maximum spiral advance angle is 11.9.
Degree.

When the groove inclination angle α was measured, about 1
The groove inclination of 5 ° was sufficiently suppressed. The groove inclination angle α is defined as shown in FIG.

Here, a straight line L1 connecting the center O of the spacer and the center A of the groove bottom and a straight line L2 connecting the center A of the groove bottom and the center B of the outer width of the groove in the cross section of the inverted portion of the PE spacer 10. Then, the groove inclination angle α is determined by these straight lines L1 and L2.
Is represented by the narrow angle of

Further, one rib 13 of the SZ spacer 10 formed by the spacer main body resin layer 8 is cut off, and FIG.
As shown in the figure, after dividing into four from the root to the tip, the resin density was measured using a density gradient tube, and the rib root a
At 0.9497, at the rib center (root side) b, 0.95
05, at the rib center c, at 0.9505, at the rib tip d,
0.9503.

Next, eight optical fibers each having a thickness of 0.4 mm and a width of 0.6 mm are accommodated in each of the grooves 12 of the SZ spacer 10 by 8 pieces (to prevent the movement of the cords and to prevent water intrusion). After filling with jelly), sheath coating was performed via a hold-down winding to obtain a 128-core SZ type optical fiber cable.

When the optical transmission performance of this optical fiber cable was measured, good performance of 0.21 to 0.22 dB / km was confirmed. (Example 2) A steel wire obtained by twisting seven steel wires having an outer diameter of 1.0 mm was introduced into a crosshead as a tensile strength member 1, and an ethylene-ethyl aclute copolymer resin (GA) was formed on the outer periphery of the tensile strength member. -006: Nippon Unicar), pre-coating inner layer 2, linear low density polyethylene resin (NUCG535)
0: manufactured by Nippon Unicar) at 200 ° C. as the pre-coating outer layer 3
To obtain a coated tensile strength wire 4 having an ethylene-ethyl aclute copolymer resin layer outer diameter of 3.6 mm and a linear low density polyethylene resin outer diameter of 5.8 mm on the outer periphery thereof.

This coated tensile wire 4 is preheated to 60 ° C. by passing through a heating tank 5 in the same manner as in Example 1, and thereafter, an extruder equipped with a rotary die 6 corresponding to the cross-sectional shape of the spacer. And a high-density polyethylene resin (Hizex 6600M: Mitsui Chemicals) with MI = 0.03 (g / 10 min) as a resin for forming the spacer body resin layer 8 by rotary extrusion coating at a speed of 7.5 m / min. After doing
It is led to the cooling zone 9 and cooled.
An E spacer 10a was obtained.

In the cooling zone 9, the air nozzles 11 are arranged in three steps as in the first embodiment. In addition, the resin discharge nozzle of the rotary die 6 is the same as the Sb / S described in the first embodiment.
The one designed so that the nb value was 0.93 was used.

In the obtained PE spacer 10a, six substantially U-shaped spiral grooves 12 each having a groove depth of 2.5 mm and a groove width of 2.5 mm are equally arranged in the circumferential direction.
No. 2 had a helical structure twisted in an SZ shape at an inversion pitch of 240 mm and an inversion angle of 360 °, had a target size and shape, and satisfied various specifications.

The minimum rib thickness at the rib base of the PE spacer 10a was about 1.85 mm, and the maximum spiral advance angle was 8.3 degrees.

When the groove inclination angle α was measured at the cross section of the inverted portion of the PE spacer 10a, it was found that the groove inclination was sufficiently suppressed to about 12 °.

Further, one rib of the SZ spacer 10a formed of the main body resin was cut out and divided into four parts from the root to the tip, and the resin density was measured with a density gradient tube. Central (root) b
Was 0.9503, the rib center c was 0.9504, and the rib tip d was 0.9502.

Next, in the same manner as in the first embodiment, four grooves each of a two-core tape-shaped optical fiber having a thickness of 0.4 mm and a width of 0.6 mm are accommodated in each groove, filled with jelly, and then held down by a presser winding. Then, sheath coating was performed to obtain a 48-core SZ type optical fiber cable. When the optical transmission performance of this optical fiber cable was measured, it was found to be 0.20 to 0.22 dB / k.
m and good performance. (Example 3) A single steel wire having an outer diameter of 2.6 mm was introduced into a crosshead as a strength member, and an ethylene-ethyl aclute copolymer resin (GA-006: manufactured by Nippon Unicar) was reserved around the periphery of the strength member. Coating inner layer, linear low density polyethylene resin (NUCG5350: manufactured by Nippon Unicar) as a pre-coating outer layer by coextrusion coating at 200 ° C.
The outer diameter of the ethyl aclute copolymer resin layer is φ3.2 mm,
The outer diameter of the linear low density polyethylene resin coating on the outer circumference is φ
A 4.5 mm coated tensile strength wire 4a was obtained.

The coated tensile wire 4a is preheated to 60 ° C. by passing through the heating tank 5 as in the first embodiment, and thereafter, an extruder provided with a rotary die 6 corresponding to the cross-sectional shape of the spacer. 7 and a high-density polyethylene resin (Hizex 6600M: manufactured by Mitsui Chemicals) with MI = 0.03 (g / 10 min) as a resin for forming the spacer main body resin layer 8, after being rotationally extruded at a speed of 7 m / min. Then, the mixture was guided to the cooling zone 9 and cooled to obtain a PE spacer 10b having an outer diameter of 10.2 mm.

In the cooling zone 9, the air nozzles 11 were arranged in three stages as in the first embodiment. In addition, the resin discharge nozzle of the rotary die 6 is the same as the Sb / S described in the first embodiment.
The one designed so that the nb value becomes 0.94 was used.

In the obtained PE spacer 10b, five substantially U-shaped spiral grooves 12 each having a groove depth of 2.5 mm and a groove width of 3.0 mm are equally arranged in the circumferential direction.
No. 2 had a helical structure twisted in an SZ shape at a reversal pitch of 150 mm and a reversal angle of 270 °, had a target size and shape, and satisfied various specifications.

The minimum rib thickness at the rib base of the PE spacer 10b was about 1.85 mm, and the maximum spiral advance angle was 8.3 degrees.

When the groove inclination angle α was measured at the cross section of the inverted portion of the PE spacer 10b, it was found that the groove inclination was about 13 °, which was sufficiently suppressed.

Further, one rib of the SZ spacer 10b formed of the main body resin was cut out and divided into four parts from the root to the tip. The resin density was measured with a density gradient tube. Central (root) b
Was 0.9505, the center c of the rib was 0.9504, and the tip d of the rib was 0.9503.

Next, in the same manner as in Example 1, five four-core tape-shaped optical fibers each having a thickness of 0.40 mm and a width of 1.1 mm were accommodated in each groove, filled with jelly, and then held down by a presser winding. Then, sheath coating was performed to obtain 100 SZ type optical fiber cables. When the optical transmission performance of this optical fiber cable was measured, it showed a good performance of 0.22 dB / km. Example 4 Aramid fiber (Kevlar 3120 dte)
x: manufactured by Toray Dupont Co., Ltd.) as a reinforcing fiber, impregnated with a vinyl ester resin (ESTA-1H-6400: manufactured by Mitsui Chemicals), drawn and formed into an outer diameter of 4.5 mm, and introduced into a crosshead die. , LLDPE resin (NUCG535
0: manufactured by Nippon Unicar Co., Ltd.), and after cooling the coating resin on the surface, the internal vinyl ester resin was cured in a steam curing tank at 145 ° C., and the coated tensile strength wire 4b having an outer diameter of φ5.8 mm was used. Got.

The coated tensile strength wire 4b is preheated to 60 ° C. by passing through the heating tank 5 in the same manner as in the first embodiment, and thereafter, an extruder provided with a rotary die 6 corresponding to the cross-sectional shape of the spacer. And a high-density polyethylene resin (Hizex 6600M: Mitsui Chemicals) with MI = 0.03 (g / 10 min) as a resin for forming the spacer body resin layer 8 by rotary extrusion coating at a speed of 7.5 m / min. After doing
It is led to the cooling zone 9 and cooled.
An E spacer 10c was obtained.

In the cooling zone 9, the air nozzles 11 were arranged in a three-stage manner as in the first embodiment. In addition, the resin discharge nozzle of the rotary die 6 is the same as the Sb / S described in the first embodiment.
The one designed so that the nb value was 0.93 was used.

In the obtained PE spacer 10c, six substantially U-shaped spiral grooves 12 each having a groove depth of 2.5 mm and a groove width of 2.5 mm are equally arranged in the circumferential direction.
No. 2 had a helical structure twisted in an SZ shape at an inversion pitch of 240 mm and an inversion angle of 360 °, had a target size and shape, and satisfied various specifications.

The minimum rib thickness at the rib base of the PE spacer 10c was about 1.85 mm, and the maximum spiral advance angle was 8.3 degrees.

When the groove inclination angle α was measured in the cross section of the inverted portion of the PE spacer 10c, it was found that the groove inclination was about 12 °, which was sufficiently suppressed.

Further, one rib of the SZ spacer 10c formed of the main body resin was cut out and divided into four parts from the root to the tip. The resin density was measured with a density gradient tube. Central (root) b
Was 0.9504, the center c of the rib was 0.9505, and the tip d of the rib was 0.9503.

Next, in the same manner as in the first embodiment, four grooves each of a two-core optical fiber having a thickness of 0.4 mm and a width of 0.6 mm were accommodated in each groove, filled with jelly, and then held down by a presser winding. Then, sheath coating was performed to obtain a 48-core SZ type optical fiber cable. When the optical transmission performance of this optical fiber cable was measured, it showed a good performance of 0.22 dB / km. (Example 5) A steel stranded wire obtained by twisting seven steel wires having an outer diameter of 1.4 mm was introduced into a crosshead as a tensile strength member 1, and an ethylene-ethyl aclute copolymer resin ( GA-006: manufactured by Nippon Unicar), pre-coated inner layer 2, linear low-density polyethylene resin (NUCG53)
50: manufactured by Nippon Unicar) as pre-coating outer layer 3 of 200
Co-extrusion coating at ℃ to obtain a coated tensile strength wire 4 having an outer diameter of an ethylene-ethyl aclute copolymer resin layer of φ4.8 mm and an outer diameter of a linear low-density polyethylene resin coating of φ9.7 mm on the outer periphery thereof. .

The coated tensile wire 4 is preheated to 60 ° C. by passing through the heating tank 5 in the same manner as in Example 1, and thereafter, an extruder equipped with a rotary die 6 corresponding to the cross-sectional shape of the spacer. 7 and a high-density polyethylene resin (Hizex 6600M: Mitsui Chemicals) having an MI of 0.03 (g / 10 min) as a resin for forming the spacer main body resin layer 8 by rotary extrusion coating at a speed of 6 m / min. , Cooling to the cooling zone 9a, the PE having an outer diameter of 15.7 mm.
The spacer 10d was obtained.

In the cooling zone 9a, air nozzles 11 having the same structure as in the first embodiment are spaced by 300 mm,
Four stages are installed along the running direction of the spacer 10d.

In the case of this embodiment, the dry air supplied into the annular space 11b is supplied from each cooling nozzle 11c.
20m almost perpendicularly (perpendicularly) to the spacer 10d
^The air was blown at a wind speed of ³ / HR to cool.

The resin discharge nozzle of the rotary die 6 used was designed so that the Sb / Snb value described above in the first embodiment was 0.95.

In the obtained PE spacer 10d, eight substantially U-shaped spiral grooves 12 having a groove depth of 2.8 mm and a groove width of 2.8 mm are uniformly arranged in the circumferential direction.
Sample No. 2 had a helical structure twisted in an SZ shape at a reversal pitch of 235 mm and a reversal angle of 360 °, had a target size and shape, and satisfied various specifications.

The minimum rib thickness at the rib base of the PE spacer 10d was about 1.5 mm, and the maximum spiral advance angle was 11.9 degrees.

When the groove inclination angle α was measured at the cross section of the inverted portion of the PE spacer 10d, the groove inclination was about 14 °, and the groove inclination was sufficiently suppressed.

Further, one rib of the SZ spacer 10c formed of the main body resin was cut out and divided into four parts from the root to the tip, and the resin density was measured with a density gradient tube. Central (root) b
Was 0.9505, the center c of the rib was 0.9506, and the tip d of the rib was 0.9504.

Next, in the same manner as in Example 1, eight optical fibers each having a thickness of 0.4 mm and a width of 0.6 mm were accommodated in each groove and filled with jelly. Then, sheath coating was performed to obtain a 128-core SZ type optical fiber cable. When the optical transmission performance of this optical fiber cable was measured, it showed a good performance of 0.21 dB / km. (Comparative Example 1) As a method of cooling the spacer main body resin, an inner diameter φ75 having a packing with a hole diameter φ16.5 mm on the outlet side.
A surfactant (MARPON FL-30: manufactured by Matsumoto Yushi) is inserted into a SUS pipe having a length of 1 mm and a length of 1 mm while passing through the pipe.
Was added in such a manner as to give a concentration of 0.1%, and warmed at 40 ° C. was introduced from below, and cooled and solidified by overflowing from above, and PE having an outer diameter of 15.7 mm was produced in the same manner as in Example 1. Spacers were obtained.

Although the cross-sectional dimensions, inversion pitch, and inversion angle of the SZ spacer were the same as those in Example 1, the groove inclination angle α in the inversion section was measured to be as large as about 25 °.

Further, one rib of the SZ spacer formed of the main body resin was cut out and divided into four parts from the root to the tip, and then the resin density was measured by a density gradient tube. (Root side) b
Was 0.9511, the center c of the rib was 0.9508, and the tip d of the rib was 0.9503.

Next, in the same manner as in Example 1, each of the grooves accommodates eight two-core tape-shaped optical fibers, and is filled with jelly.
A core SZ type optical fiber cable was obtained. When the optical transmission performance of this optical fiber cable was measured,
The performance varied from 5 to 0.55 dB / km.

[0063]

As described above, according to the spacer for an optical fiber cable, the optical fiber cable using the spacer, and the method of manufacturing the spacer according to the present invention, the inclination of the groove in the inversion portion is suppressed. Further, it is possible to realize the deep groove of the SZ spacer without deteriorating the transmission loss.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a main part of a manufacturing process of a method for manufacturing an optical fiber cable spacer according to the present invention.

FIG. 2 is a detailed explanatory view of an air nozzle used in the manufacturing method of FIG.

FIG. 3 is a sectional view of an optical fiber cable spacer obtained by the manufacturing method of FIG. 1;

FIG. 4 shows a groove inclination angle α of an optical fiber cable spacer.
FIG.

FIG. 5 is an explanatory diagram of a traveling angle of a spiral groove of a spacer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 strength member 2 pre-coating inner layer 3 pre-coating outer layer 4 coating tensile strength line 5 heating tank 6 rotating die 7 extruder 9 cooling zone 10 spacer for optical fiber cable 11 air nozzle 12 spiral groove 13 rib

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H01B 11/00 H01B 11/00 L B29K 23:00 B29K 23:00 B29L 11:00 B29L 11:00 (72) Inventor Nori Ishii 2-1-1, Yabuta-nishi, Gifu City, Gifu Prefecture Ube Nitto Kasei Co., Ltd.F-term (reference) KA17 KB18 KK56 KL58 KL80

Claims (4)

[Claims] 1. An optical fiber housing in which an intermediate coating layer is formed of a thermoplastic resin compatible with polyethylene around a central tensile strength member, the direction of which is periodically inverted along the longitudinal direction, and which is continuous in the longitudinal direction. In a polyethylene optical fiber cable spacer in which a spacer main body coating layer having a spiral groove is provided on the outer periphery of the intermediate coating layer, the spiral groove has a minimum rib thickness of 1. 1 An optical fiber cable spacer characterized by having a groove depth of at least 0 mm, a groove depth of at least 2.0 mm, a maximum helical advancing angle of at least 8 degrees, and a groove inclination angle of at least 18 degrees at the cross section of the spacer at the inversion portion. 2. The optical fiber cable spacer according to claim 1, wherein the rib defining the side surface of the spiral groove has a resin density at a substantially root portion compared to a resin density at a tip portion or a central portion. The smallest fiber optic cable spacer. 3. An optical fiber cable using the spacer according to claim 1, wherein at least one or more of the spiral grooves contains an optical fiber such as a tape. 4. An optical fiber housing in which an intermediate coating layer is provided around a central tensile strength member with a thermoplastic resin compatible with polyethylene, and the direction of which is periodically inverted along the longitudinal direction and continuous in the longitudinal direction. The method for manufacturing an optical fiber cable spacer, wherein the spacer main body coating layer having a spiral groove for the optical fiber cable is provided on the outer periphery of the intermediate coating layer. Along the running direction of the spacer, a plurality of cooling air nozzles are installed in multiple stages at predetermined intervals, and the dry air is passed through the air nozzle from a position separated from the outer periphery of the spacer by a predetermined interval. A method of manufacturing a spacer for an optical fiber cable, wherein the spacer is cooled by spraying substantially perpendicularly to an outer periphery of the spacer.