JP2002365505A - Die for extrusion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die for extrusion which prevents resin from stagnating in the way of a connection part, when molten resin is extruded and reliably connects two or more members via the thin connection part. SOLUTION: Tapers 27a, 27b, of which the passage area is made to decrease from the upstream side to the downstream side in the direction of extrusion of resin member, are formed on the connection part 26c which connects the passages 26a, 26b of the die 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion die, and more particularly, to a method in which an outer peripheral portion of a core wire of two or more optical fiber cables is covered with a resin member and connected via a thin connecting member. The present invention relates to an extrusion die that can be subjected to extrusion processing.

[0002]

2. Description of the Related Art In an optical fiber cable used for signal transmission, a plurality of optical fiber cables are provided in parallel in order to increase the channel and speed of the signal to be transmitted. For example, as one of the manufacturing methods of the medium,
There is extrusion molding, and as this type of extrusion molding, for example, the one shown in FIG. 7 is known.

In FIG. 7, reference numeral 1 denotes an extrusion die, in which two flow paths 3 and 4 are formed via a connecting portion 2. Fig. 8
As shown in FIG. 3A, two primary coated fiber cables 6a and 6b, each of which is woven with fibers 4a and 4b, are inserted into the outer peripheral portions of the optical fiber cables 3a and 3b. Since the molten resin such as PVC is extruded and supplied to the flow paths 3 and 4 and the connecting portion 5 via the supply path, the outer peripheral portions of the primary coated fiber cables 6a and 6b are coated with the molten resin. For this reason, as shown in FIG. 8B, a two-core optical fiber cable 9 in which the jacket 8 is coated on the outer peripheral portions of the primary coated fiber cables 6a and 6b via the connecting portion 7 can be obtained. .

In order to obtain the two-core optical fiber cable 9 as described above, the inner peripheral surfaces of the flow paths 3 and 4 are coated so as to cover the outer peripheral portions of the primary coated fiber cables 6a and 6b with molten resin. It is necessary to keep it parallel to some extent (usually the inner diameter is about 5 mm), and it is necessary to reduce the gap (about 0.15 to 0.17 mm) of the connecting portion 5 as much as possible. Because, when the inner peripheral surfaces of the flow paths 3 and 4 are not parallel and the gap of the connecting portion 5 is large, the primary coated fiber cables 6a and 6b cannot be connected via the connecting portion 7 and are separated. It is because it becomes.

[0005] The optical fiber cable 9 thus formed is configured such that the outer sheath 8 at the end side is peeled off to expose the optical fiber cables 3a and 3b and to be connected to a connector (not shown).

[0006]

However, in such a conventional die 1, the gap from the entrance to the exit of the connecting portion 5 is formed in parallel with a constant gap (about 0.15 mm). In some cases, the molten resin does not flow from the inlet portion to the outlet portion, but stagnates at the center of the connecting portion 5 in the resin flow direction. For this reason, the primary coated fiber cables 6 and 6b cannot be sufficiently connected via the connecting portion 7, and may be separated.

Here, the relationship among the outer diameter of the optical fiber cable 9, the thickness of the jacket 8, and the thickness of the connecting portion 7 is preferably as shown in FIG.

For this reason, it is only necessary to increase the gap between the connecting portions 5. However, if the gap is increased, the connecting portion 5 is removed when the outer sheath 8 on the end side of the optical fiber cable 9 is peeled off as described above. There is a problem that the jacket portion 8 is pulled by the connecting portion 7 and is broken by the thickness of the portion 7, resulting in poor appearance and reduced shielding performance.

Accordingly, the present invention is directed to an extrusion die which can prevent two or more members from being reliably connected via a thin connecting part by preventing the resin from stagnating in the middle of the connecting part when the molten resin is extruded. It is intended to provide.

[0010]

According to the present invention, in order to solve the above-mentioned problems, at least two or more flow paths for extruding a resin member are provided, and the flow path forms a connecting portion of a minute gap. In the extrusion dies that are connected to each other in close proximity to each other, a taper is formed such that the flow path area decreases from the upstream side to the downstream side in the extrusion direction of the resin member of the connection portion.

In this case, since the taper is formed such that the flow path area decreases from the upstream side to the downstream side in the extrusion direction of the resin member of the connecting portion, the resin stagnates in the middle of the connecting portion when the resin is extruded. And two or more members can be reliably connected via a thin connecting portion.

[0012] For this reason, for example, when the outer peripheral portion of the core of the optical fiber cable is covered with a resin and this resin is connected via the connecting portion, the connecting portion can be made thin, so that the end side of the optical fiber cable can be thinned. When the outer sheath portion is peeled off, the outer sheath portion can be prevented from being broken by being pulled by the connecting portion, and the appearance of the multi-core optical fiber cable can be improved, and the shielding property can be improved. It can be prevented from lowering.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 6 are views showing an embodiment of an extrusion die according to the present invention, and are views showing an extrusion molding machine provided with the extrusion die.

First, the configuration will be described. FIG. 1 shows a two-core optical fiber cable which is a molded product formed by the extrusion molding machine of the present embodiment. In FIG. 1, reference numeral 11 denotes a two-core optical fiber cable.
An outer jacket portion 16 is formed by covering the outer peripheral portions of two primary coated fiber cables 14a and 14b braided with 13a and 13b via a resin connecting portion 15.

2 to 5 are views showing an extruder. In FIG. 2, reference numeral 21 denotes an extrusion molding machine. The extrusion molding machine 21 includes a body 22 having a molten resin supply passage 22a formed therein, a die holder 23 fitted to an inner peripheral portion of the body 22, and a die. A point member 24 fitted to the inner peripheral portion 23a of the holder 23 and a die 25 fitted to the die holder 23 and arranged to face the point member 24 are provided.

As shown in FIG. 3, two supply paths 24a and 24b are formed in the inner periphery of the point member 24, and the two coated fiber cables 14a supplied to the inner periphery 23a of the die holder 23 are formed. , 14b are supplied to supply paths 24a, 24b.

As shown in FIGS. 4 to 6, a die mask 26 is attached to the end of the die 25. The die mask 26 has a screw 31 screwed into the die 25 through a screw hole 26d. Is fixed to the die 25.

A flow path 25a is formed in the inner peripheral portion of the die 25, and this flow path 25a communicates with two flow paths formed in the die mask 26. That is, the die mask 26 has two flow paths 26a and 26b through which the molten resin is supplied.
Are formed, and these flow paths 26a and 26b are closely connected to each other via a connection portion 26c having a minute gap.

The connecting portion 26c is formed with tapered portions 27a and 27b from the upstream side (left side in FIG. 2) to the downstream side (right side in FIG. 2) in the extrusion direction of the resin member so as to reduce the flow area. In this embodiment, the gap on the upstream side of the connecting portion 26c is formed at 1.15 mm, and the gap on the downstream side is formed at 0.15 mm. In this embodiment, the dice 25 and the dice mask 26 correspond to the dice described in the claims.

Next, the operation will be described.

Two primary coated fiber cables 14a and 14b, in which fibers 13a and 13b are braided on the outer periphery of the optical fiber cables 12a and 12b, are connected to a die holder 23 from the left side in FIG.
Supply paths 24a, 24 of the point member 24 through the inner peripheral surface 23a of the
b, the die holder 23 and the point member 24 are supplied from the supply path 22a through the supply path 23b of the die holder 23.
The molten resin is supplied through the supply path 28 between the two.

Since this molten resin is supplied to the channels 26a, 26b of the die mask 26a through the channel 25a of the die 25, the primary coated fiber cables 14a, 14b supplied to the channels 26a, 26b through the channel 25a. While being coated on the outer peripheral portion of the primary coated fiber cable 14a, 14b, it is extruded from the die mask 26 and connected to the outer peripheral portion of the primary coated fiber cable 14a, 14b as shown in FIG.
An optical fiber cable 11 in which a jacket 16 is coated via 15
Is obtained.

In this embodiment, the tapered portions 27a and 27b are formed such that the flow path area is reduced from the upstream side to the downstream side in the extrusion direction of the resin member of the connecting portion 26c. The two primary coated fiber cables 14a and 14b can be reliably connected via the thin connecting portion 26c without the resin stagnation.

Further, since the connecting portion 15 can be made thin, when the outer covering portion 16 on the end side of the optical fiber cable 11 is peeled, the outer covering portion 16 is pulled by the connecting portion 15 and cracked. Can prevent the two-core fiber optic cable
The appearance of 11 can be improved, and the shielding property can be prevented from deteriorating.

Although the present embodiment shows a two-core optical fiber cable, the present invention is not limited to this, and an optical fiber cable having three or more cores may be formed. In this case, a die in which three or more flow paths are connected via a connecting portion may be used.

[0027]

According to the present invention, a taper is formed such that the flow path area decreases from the upstream side to the downstream side in the extrusion direction of the resin member of the connecting portion. The resin does not stagnate, and the two or more members can be reliably connected via the thin connecting portion.

For this reason, for example, when the outer peripheral portion of the core of the optical fiber cable is covered with a resin and the resin is connected via the connecting portion, the connecting portion can be made thin, so that the end portion of the optical fiber cable can be made thinner. When the outer sheath portion is peeled off, the outer sheath portion can be prevented from being broken by being pulled by the connecting portion, and the appearance of the multi-core optical fiber cable can be improved, and the shielding property can be improved. It can be prevented from lowering.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an extrusion die according to the present invention, and is a cross-sectional view of an optical fiber cable formed by the extrusion die.

FIG. 2 is a cross-sectional view of an extrusion forming apparatus provided with an extrusion die of one embodiment.

3A is a cross-sectional view of a die holder according to one embodiment, and FIG. 3B is a front view of the die holder.

FIG. 4 is a cross-sectional view of a dice and a dice mask according to one embodiment.

FIG. 5A is a front view of a die mask according to one embodiment,
(B) is a sectional view thereof.

FIG. 6A is a perspective view of a dice mask according to one embodiment,
(B) is a block diagram of a flow path and a connecting portion formed in the die mask.

FIG. 7 is a perspective view of a conventional die.

FIG. 8A is a cross-sectional view of a primary coated fiber cable,
(B) is a sectional view of an optical fiber cable formed by a conventional extrusion die.

FIG. 9 is a diagram illustrating the relationship between the sizes of an optical fiber cable, a jacket portion, and a connecting portion.

[Explanation of symbols]

 25 dice 26 dice mask (die) 26a, 26b Flow path 26c Connecting part 27a, 27b Taper

Claims (1)

[Claims] 1. A flow path for extruding a resin member is at least two.
In the extrusion die, the flow paths are closely connected via a connection part of a minute gap, and the flow path is from the upstream side to the downstream side in the extrusion direction of the resin member of the connection part. An extrusion die, wherein a taper is formed so as to reduce the area.