JP3120950B2 - Ferrule Injection Mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule injection mold.

[0002]

2. Description of the Related Art Ferrules are parts of optical fiber connectors used for connecting optical fibers. The connection of the optical fiber is performed by arranging a pair of ferrules and abutting a sleeve on both fitting portions. Therefore, the uniformity of the outer diameter of the fitting portion of the ferrule and the coaxial accuracy between the outer diameter and the insertion hole of the optical fiber greatly affect the connection loss of the optical fiber and the detachability as a connector.

However, when the ferrule is integrally molded by injection molding of a synthetic resin, as the distance from the gate at the fitting portion increases, the flow resistance of the molten resin at the time of injection increases, and the filling pressure at one end is increased. Is lower than that near the gate. Thereby, the packing density at one end decreases. As a result, in particular, the outer diameter of the fitting portion of the ferrule gradually tapers toward one end, thereby causing an uneven cross-sectional shape of the fitting portion, which not only increases the connection loss of the optical fiber, but also increases the connector loss. It hinders the detachability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional technical problem.
It is as follows. The first aspect of the present invention provides a fitting portion 1b having a cylindrical surface having a tapered portion 1a whose outer diameter gradually decreases toward one end, a flange portion 1c having a larger diameter than the fitting portion 1b, and a flange shape. Holding portion (1d, 1) having a smaller diameter than portion 1c
f) is formed sequentially from one end, and in the center, a fine hole 1g and a large hole 1i are formed in a ferrule injection molding die for forming a ferrule 1 formed concentrically sequentially from one end. A cavity A defined by the mold 2 and the second mold 3 and having a gate 3c between the two molds 2 and 3 is formed in one of the first mold 2 and the second mold 3 and has the taper. A first cavity A1 in which a fitting portion 1b having a shape portion 1a is defined, and a thin pin 13 for forming the small hole 1g is protruded;
It is formed on the other of the mold 2 or the second mold 3 to partition the flange-like portion 1c and the holding portions (1d, 1f),
A second pin having a through-hole 12a capable of receiving the other end of the thin pin 13 and projecting the thick pin 12 for forming the thick hole 1i;
A cavity A2, and a vacuum vent 5 connected to a portion defining the tapered portion 1a of the first cavity A1 to discharge air therefrom.
4c is formed, and the other end of the through hole 12a is connected to a compressed air supply source 4 for injecting compressed air from one end of the thin pin 13 to the other end thereof. It is a mold. The invention according to claim 2 is characterized in that a fitting portion 1b having a cylindrical surface having a tapered portion 1a whose outer diameter gradually decreases toward one end, a flange portion 1c having a larger diameter than the fitting portion 1b, a flange shape. The holding portions (1d, 1f) having a smaller diameter than the portion 1c are sequentially formed from one end, and at the center,
A ferrule injection molding die for forming a ferrule 1 formed concentrically in order from one end with a fine hole 1g and a large hole 1i, partitioned by a first die 2 and a second die 3, A cavity A having a gate 3c between the two molds 2 and 3 is formed in one of the first mold 2 and the second mold 3, and defines a fitting portion 1b having the tapered portion 1a. A first cavity A1 in which a thin pin 13 for forming the pore 1g is protruded, and formed in the other of the first mold 2 or the second mold 3,
The flange-shaped portion 1c and the holding portions (1d, 1f) are partitioned, and the through-hole 12a capable of receiving the other end of the thin pin 13 is provided. A second cavity A2, and an air vent passage 14a, which is connected to a vacuum pump 5 and discharges air at a position defining the tapered portion 1a of the first cavity A1.
14b and 14c are formed, and the air vent passage 1 is provided at the other end of the through-hole 12a at a location defining the periphery of the thin pin 13, the flange-like portion 1c and the holding portions (1d, 1f).
A ferrule injection molding die to which a vacuum pump 6 for discharging air from 5a, 15b, 15c, 15d is connected. The compressed air supply source 4 is provided in parallel with the vacuum pump 6, and the compressed air supply source 4 is selectively connected to the through hole 12a.
3. The ferrule injection molding die according to claim 2, wherein compressed air can be injected from one end to the other end.

[0005]

According to the first aspect of the present invention, a cavity A is defined between the two dies 2 and 3 in a clamped state, and the thin pin 13 is inserted into one end of the through hole 12a of the thick pin 12. The other end is fitted to form a core pin supported at both ends. If the process shifts to the injection step from this state, the molten resin is injected into the cavity A from the gate 3c between the dies 2 and 3. The molten resin injected into the cavity A flows separately in both directions, and the molten resin filled in the second cavity A2 causes the flange-like portion 1c of the ferrule 1 and the holding portion (1).
d, 1f) is formed, and a fitting portion 1b having a tapered portion 1a of the ferrule 1 is formed by the molten resin filled in the first cavity A1, and a fine hole 1g and a large hole 1i are formed at the center. It is formed as an optical fiber insertion hole.

In the fitting portion 1b having the tapered portion 1a of the ferrule 1, since air vent passages 14a, 14b, and 14c for discharging air are formed at locations where the tapered portion 1a is partitioned, vacuum is applied from this location. The air is forcibly removed by the pump 5 and the compressed air is supplied from the compressed air supply source 4 through the gap between the through hole 12a and the thin pin 13 to form the compressed air.

That is, the molten resin that has flowed into the first cavity A1 flows toward one end through a uniform annular cross-section around the thick pin 12. The molten resin that has reached one end side from the thick pin 12 is pressed in the outer diameter direction because compressed air is injected through a gap between the through hole 12a and the thin pin 13, and is pressed toward the first cavity A1. Progress is urged while closely contacting the ward screen. The compressed air sent through the gap between the through hole 12a and the thin pin 13 is discharged from the air vent passages 14a, 14b (14c). As described above, the compressed air sent from the gap between the through-hole 12a and the thin pin 13 causes the air vent passages 14a, 1 formed in the portion defining the tapered portion 1a of the first cavity A1.
By being discharged from 4b (14c), the molten resin proceeds so as to be pushed in on the air flow in addition to the injection pressure, so that the molten resin quickly and satisfactorily fills one end in the first cavity A1. . In particular, by discharging air from the air vent passages 14a and 14b formed at locations defining the tapered portion 1a of the first cavity A1, the molten resin comes into close contact with the vicinity of one end of the adjacent fitting portion 1b. , And the outer diameter in the vicinity thereof can be favorably obtained.

In addition, a fitting portion 1 having a tapered portion 1a
b is defined by the first cavity A1, and the flange-like portion 1c and the holding portions (1d, 1f) are defined by the second cavity A2. Therefore, the flange-like portion 1c is defined by the first cavity A1. As compared with the case, the length from the gate 3c to the tapered portion 1a is shortened, and the decrease in the filling pressure in the first cavity A1 is further suppressed.

When the entire interior of the cavity A is filled with the molten resin, after a pressure-holding and cooling step, the mold is opened and a molded product is taken out. In the ferrule 1 which is a molded product, the outer diameter of the fitting portion 1b as well as the fine hole 1g is precisely molded. Thus, when a pair of ferrules 1 each having an optical fiber inserted into the small hole 1g and the large hole 1i are abutted to each other and a sleeve is externally fitted to the pair of fitting portions 1b to form an optical fiber connector, the connection state of the optical fibers is changed. Is obtained satisfactorily, and the connection loss is reduced.

In addition, at the time of mold clamping, the other end of the thin pin 13 is fitted into the through hole 12a of the thick pin 12, and the cavity A
A core pin supported at both ends is formed therein. Thus, twisting and bending of the pins 12 and 13 due to the flow pressure of the resin are prevented, the fine hole 1g and the large hole 1i of the ferrule 1 are bent, and the outer diameter of the fitting portion 1b is the same as the fine hole 1g. The core state is reliably prevented from becoming bad. As a result, connection loss as an optical fiber connector is reduced.

According to the second aspect of the present invention, when the process shifts from the mold clamping state to the injection step, the molten resin is injected into the cavity A from the gate 3c between the dies 2 and 3. Cavity A
The molten resin injected into the
The flange-like portion 1c and the holding portions (1d, 1f) of the ferrule 1 are formed by the molten resin filled in the cavity A2, and the tapered shape of the ferrule 1 is formed by the molten resin filled in the first cavity A1. A fitting portion 1b having a portion 1a is formed, and a fine hole 1g and a large hole 1i are formed at the center.

In this injection molding, air is forcibly released from the air vent passages 14a, 14b and 14c at the locations defining the tapered portion 1a by the vacuum pump 5, and the air is removed from the through hole 12a and the thin pin 13. The molding proceeds while the air is forcibly evacuated by the vacuum pump 6 from the gap therebetween and the air bleed passages 15a to 15d. That is, the filling of the molten resin proceeds while the pressure in the cavity A is reduced. For this reason, the molten resin that has flowed into the first cavity A1 quickly reaches one end of the thick pin 12 and then, despite the enlarged cross section of the first cavity A1 at the one end, Is quickly sucked into the first cavity A1 and filled with a quick and substantially uniform filling pressure. In particular, by discharging air from the air vent passages 14a, 14b (14c) formed at locations defining the tapered portion 1a of the first cavity A1, the molten resin comes into close contact with the vicinity of one end of the adjacent fitting portion 1b. As a result, the outer diameter in the vicinity can be obtained favorably.

In addition, the fitting portion 1 having the tapered portion 1a
b is defined by the first cavity A1, and the flange-like portion 1c and the holding portions (1d, 1f) are defined by the second cavity A2. Therefore, the flange-like portion 1c is defined by the first cavity A1. As compared with the case, the length from the gate 3c to the tapered portion 1a is shortened, and the decrease in the filling pressure in the first cavity A1 is further suppressed.

When the entire inside of the cavity A is filled with the molten resin, after a pressure-holding and cooling step, the mold is opened and a molded product is taken out. In the ferrule 1 which is a molded product, the outer diameter of the fitting portion 1b as well as the fine hole 1g is precisely molded. Thus, when a pair of ferrules 1 each having an optical fiber inserted into the small hole 1g and the large hole 1i are abutted to each other and a sleeve is externally fitted to the pair of fitting portions 1b to form an optical fiber connector, the connection state of the optical fibers is changed. Is obtained satisfactorily, and the connection loss is reduced.

In addition, at the time of mold clamping, the other end of the thin pin 13 fits into the through hole 12a of the thick pin 12, and the cavity A
A core pin supported at both ends is formed therein. Thus, twisting and bending of the pins 12 and 13 due to the flow pressure of the resin are prevented, the fine hole 1g and the large hole 1i of the ferrule 1 are bent, and the outer diameter of the fitting portion 1b is the same as the fine hole 1g. The core state is reliably prevented from becoming bad. As a result, connection loss as an optical fiber connector is reduced.

According to the third aspect of the present invention, at the time of injection molding, the air vent passages 14a, 14
b and 14c, the air is forcibly released, and the compressed air supply source 4 causes the through hole 12a and the thin pin 1
3, while the compressed air is forcibly sent through the gap between the molten resin 3 and the molten resin. Thus, the filling of the molten resin into the first cavity A1 proceeds while receiving the same operation as the first aspect of the invention.

Then, the tip of the molten resin has a tapered portion 1a.
When it has reached the vicinity, the compressed air supply source 4 is stopped, and the vacuum pump 6 is driven.
The cavity A is filled with the molten resin while forcibly bleeding air through the gap between the cavity 3 and the air vent passages 15a to 15d. In this way, it is possible to obtain the ferrule 1 in which burrs near the tapered portion 1a due to the air vent passages 14a and 14b are prevented and sinks are suppressed. Since the flange-like portion 1c and the holding portions (1d, 1f) of the ferrule 1 do not actively participate in the connection performance of the optical fiber, the required accuracy is sufficiently obtained only by bleeding the air by the vacuum pump 6.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show one embodiment of a ferrule injection mold according to the present invention. First, the ferrule will be described with reference to FIGS. Ferrule 1
It is formed integrally with a synthetic resin to form a cylindrical shape, and its outer diameter is a small-diameter cylindrical surface having a tapered portion 1a whose diameter gradually decreases toward one end from one end (the left end in FIG. 4). A fitting portion 1b, a large-diameter flange-like portion 1c, a medium-diameter short cylindrical portion 1d, and a minimum-diameter cylindrical surface portion 1f are formed. A tapered hole 1h and a large-diameter thick hole 1i gradually increasing in diameter are formed concentrically. The thick hole 1i extends to the inside of the fitting portion 1b. A plurality of cutouts 1j (four in FIG. 5) are formed in the flange-like portion 1c at predetermined intervals in contact with the short cylindrical portion 1d. 1g of fine pores, 1h of tapered holes and 1i of large holes
The optical fiber insertion hole is formed, and the optical fiber inserted from the thick hole 1i side is bonded and fixed to the thick hole 1i and the fine hole 1g.

A ferrule injection molding die for molding the ferrule 1 will be described. The ferrule injection molding mold includes a movable first mold 2 and a fixed second mold 3, and the first mold 2 is connected to a movable side receiving plate 29 and a movable side mounting plate 29a. Attached to the movable mold clamping plate,
It is driven back and forth by a toggle or direct acting type clamping device. An O-ring 28 is interposed between the first mold 2 and the movable-side receiving plate 29 as shown in FIG.
1 is prevented from leaking, and airtightness is maintained between the second mold 3 and the fixed-side mounting plate 39 by an O-ring 38 as shown in FIG. Leakage of air from the passages 14a, 14b, 14c is prevented.

The cavity A defined between the first mold 2 and the second mold 3 has a sprue 3 as shown in FIGS.
a, one runner 3b and one gate 3c are formed, but a plurality may be formed. The positioning of the two dies 2 and 3 is performed by a taper guide provided on the parting surface, so that the center lines CL of the two dies 2 and 3 in the clamped state exactly match.

The cavity A includes a first cavity A1 and a second cavity A2. The first cavity A1 is
The tapered portion 1a of the ferrule 1 is formed in the second mold 3.
And a small-diameter thin pin 13 for forming a fine hole 1 g is protruded from the second mold 3.
The second cavity A2 is formed in the first mold 2, defines a flange-like portion 1c and holding portions (1d, 1f), and has a large-diameter thick pin 12 for forming a tapered hole portion 1h and a large hole 1i. It protrudes from the first mold 2. Accordingly, one end of the thick pin 12 gradually decreases in diameter toward one end to form a tapered portion 12b. The thick pin 12 has a through hole 12a in the direction of the central axis, and one end of the through hole 12a forms a gap δ having a slight annular cross section shown in FIG. The end is insertable, and the other end of the thin pin 13 is inserted into the through hole 12a of the thick pin 12 to form a core pin in the cavity A.

The other end of the through hole 12a is connected to a compressor 4 which is a compressed air supply source for injecting compressed air toward the periphery of the thin pin 13 forming the core pin.
In addition, air vent passages 14a, 14 for discharging air are provided at the positions defining the tapered portion 1a of the first cavity A1.
4b is formed. One air vent passage 14a is
The other end of the tapered portion 1a is connected to the other end, and the other air vent passage 14b is connected to one end of the tapered portion 1a. The two air vent passages 14a and 14b are one air vent passage 1.
4c and connected to a vacuum pump 5. Further, the short cylindrical portion 1d and the cylindrical surface portion 1f of the second cavity A2.
Air vent passage 15 for discharging air
a, 15b and 15c are formed. Specifically, air vent passages 15a and 15b are respectively formed at one end and the other end of a portion that defines the short cylindrical portion 1d, and the cylindrical surface portion 1d is formed.
An air vent passage 15c is formed at the other end of the section defining f. Each air vent passage 15a, 15b, 15c
Are joined to one air vent passage 15d, and connected to the compressor 4 and the vacuum pump 6 via the on-off valve 7 together with the other end of the through hole 12a. The compressor 4 and the vacuum pump 6 connected in parallel to the through hole 12a and the air vent passage 15d are selectively driven.

Next, the operation of the above embodiment will be described. The molding cycle of the injection molding apparatus is the same as that of a normal molding cycle, and the steps of closing the mold, closing the mold, injecting, holding pressure, cooling, plasticizing and the like proceed sequentially. In the clamped state, the cavity A is defined, and the other end of the thin pin 13 is fitted into one end of the through hole 12a of the thick pin 12, thereby forming a core pin. One end of the thick pin 12 reaches the fitting portion 1b.

When the process shifts from this state to the injection step, the molten resin in the injection molding machine is injected from the nozzle and passes through the sprue 3a, the runner 3b and the gate 3c in the second mold 3, and one end of the second cavity A2. It is injected from the part. The molten resin injected into the second cavity A2 flows to the right and left separately, and the molten resin injected and filled into the second cavity A2 causes the flange-like portion 1c of the ferrule 1 and the short cylindrical portion 1 to flow.
d and the cylindrical surface part 1f are formed, and the ferrule 1 is formed by the molten resin injected and filled in the first cavity A1.
Is formed, and a fine hole 1g and a large hole 1i are formed at the center.

The flange portion 1c, the short cylindrical portion 1d and the cylindrical surface portion 1f of the ferrule 1 can be formed by closing the on-off valve 7 while bleeding air through the air bleed passages 15a, 15b, 15c and 15d. The flange-like portion 1c, the short tube portion 1d, and the cylindrical surface portion 1f of the ferrule 1 do not actively participate in the connection performance of the optical fiber.
The required accuracy can be obtained only by bleeding air from a to 15d.

On the other hand, the fitting portion 1b having the tapered portion 1a of the ferrule 1 forcibly vents the air through the air vent passages 14a, 14b and 14c by the vacuum pump 5, and the thinner hole of the through hole 12a by the compressor 4. The molding is performed while the compressed air is forcibly sent through the gap δ between the pin 13. The air sent by the compressor 4 can also suppress cooling of the molten resin as heated air.

As a result, the molten resin that has flowed into the first cavity A1 flows almost uniformly toward the one end on the uniform annular cross-section around the thick pin 12 and reaches the tapered portion 12b. On the one end side of the tapered portion 12b, the cross section of the first cavity A1 is enlarged, so that there is a tendency that a gap is formed between the second cavity 3 and the screen of the first cavity A1. However, since the compressed air is injected through the gap δ between the through-hole 12a and the thin pin 13, the molten resin B is pressed radially outward as shown in FIG. Proceed in close contact with the ward screen. The compressed air sent through the gap δ is discharged from the air vent passages 14a to 14c. Further, the compressed air sent from the gap δ is discharged from the air vent passages 14a to 14c, so that the molten resin B is pushed in on the air flow in addition to the injection pressure at one end side from the tapered portion 12b. Therefore, the molten resin B quickly and satisfactorily fills one end in the first cavity A1. In particular, the air vent passages 14a, 14b (14) formed at the locations defining the tapered portion 1a of the first cavity A1.
By discharging the air from c), the outer diameter near the one end of the adjacent fitting portion 1b can be favorably obtained.

In addition, the tapered portion 1a and the fitting portion 1b are partitioned by the first cavity A1, and the flange-shaped portion 1c
And the holding portions (1d, 1f) are defined by the second cavities A2, so that the flange-like portions 1c are divided by the first cavities A.
1, the length from the gate 3c to the tapered portion 1a is shorter than that of the first cavity A.
A decrease in the filling pressure in the chamber 1 is suppressed.

When the leading end of the molten resin B reaches the air vent passage 14a connected to the other end of the tapered portion 1a, the air in the first cavity A1 is thereafter discharged to the air vent passage 14b connected to one end of the tapered portion 1a. It is forcibly exhausted from only. In this way, the tip of the molten resin B is tapered 1a.
, The compressor 4 is stopped, and the first cavity A1 is filled with the molten resin B. When the first cavity A1 is filled with the molten resin B, the vacuum pump 5 is stopped. Note that the compressor 4 can be stopped immediately before the tip of the molten resin B reaches the air vent passage 14a connected to the other end of the tapered portion 1a. If the compressor 4 is stopped, the suction force of the vacuum pump 5 can be reduced thereafter, so that the flow of the molten resin B from the air vent passages 14a and 14b closed by the molten resin B and the occurrence of burrs are suppressed. Is done.

In such injection molding, the second mold 3
The other end of the small-diameter thin pin 13 for molding the fine hole 1g formed in the first mold 2 is formed by the tapered hole 1h and the thick hole 1 formed in the first mold 2.
A core pin whose both ends are supported in the cavity A is fitted into the through-hole 12a of the thick pin 12 for molding i. Thus, twisting and bending of the pins 12 and 13 due to the flow pressure of the resin are prevented, the formed fine hole 1g and the thick hole 1i of the ferrule 1 are bent, and the outer diameter of the fitting portion 1b and the fine hole 1g are reduced. It is possible to reliably prevent the concentric state of the lens from deteriorating. As a result, connection loss as an optical fiber connector is reduced.

When the entirety of the cavity A is filled with the molten resin B, after a pressure-holding and cooling step, the mold is opened and a molded product is taken out. In the ferrule 1 which is a molded product formed in this manner, the outer diameter of the fitting portion 1b as well as the fine hole 1g is precisely molded. Then, a pair of ferrules 1 into which an optical fiber (not shown) is inserted are brought into contact with the small hole 1g, the tapered hole 1h, and the large hole 1i, and the pair of fitting portions 1b
When a connector of an optical fiber is formed by externally fitting a sleeve to the optical fiber, the connection state of the optical fiber can be precisely obtained, and the connection loss can be reduced.

By the way, in the above embodiment, the compressor 4 is determined from the gap δ between the through hole 12a and the thin pin 13.
However, the vacuum pump 6 is driven in place of the compressor 4, and not only the air is evacuated from the air vent passages 14a to 14c by the vacuum pump 5, but also the gap δ and the air vent passages 15a to 15c. The fitting portion 1b having the tapered portion 1a of the ferrule 1 can be formed while forcibly bleeding air from 15d.
At that time, the on-off valve 7 opens.

According to this, the entirety of the cavity A, in particular, the first
Filling proceeds. For this reason, the injected molten resin rapidly advances in the first cavity A <b> 1 and reaches the tapered portion 12 b of the thick pin 12. Thereafter, although the cross section of the first cavity A1 is enlarged at one end portion side from the tapered portion 12b, the molten resin is sucked and quickly flows into the first cavity A1 and quickly and almost reaches the one end portion of the first cavity A1. Fill with uniform filling pressure. Also, the second cavity A2
Since the inside of the ferrule 1 is filled with the molten resin B under reduced pressure, the flange-like portion 1c, the short cylindrical portion 1d, and the cylindrical surface portion 1f of the ferrule 1 are quickly and almost uniformly formed by the filling pressure.

Further, at the initial stage of the start of injection, compressed air is sent from the gap δ by the compressor 4 and thereafter,
The air in the first cavity A1 can be discharged by the vacuum pump 6. According to this, in the first cavity A1, immediately after the start of injection, air is forcibly evacuated from the air bleed passages 14a to 14c by the vacuum pump 5, and the compressor 4 causes the through-hole 12a and the thin pin 13 to communicate with each other. The injection is performed while the compressed air is forcibly fed through the gap δ between the above, so that the injection process proceeds in substantially the same manner as in the above embodiment. The air vent passage 14 is connected to the other end of the tapered portion 1a.
After reaching the vicinity of a, the compressor 4 is stopped and the operation is switched to the operation of the vacuum pump 6 to forcibly discharge the air in the cavity A. In this way, the ferrule 1 in which the fine holes 1g and the fitting portions 1b are precisely formed can be obtained, and sinks due to the remaining air in the cavity A can be prevented more favorably than in the above embodiment. . In addition,
When the vacuum pump 6 is driven, the on-off valve 7 is opened to prevent air from remaining in the second cavity A2 at the end of the injection step.

[0035]

As will be understood from the above description,
According to the ferrule injection mold of the present invention, the following effects can be obtained. By molding while controlling the air in the cavity (excess air or supplying compressed air), the filling pressure of the molten resin at one end is prevented from lowering, and the filling pressure is almost the same as that near the gate. And a decrease in the packing density at one end can be prevented. Thereby, the outer diameter of the sectional shape of the fitting portion of the ferrule can be obtained uniformly. In addition, a ferrule with a very good coaxial state between the outer diameter and the optical fiber insertion hole can be obtained by the arrangement of the thin pins and the thick pins. As a result, not only the connection loss of the optical fiber is reduced, but also the detachability of the connector is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of a ferrule injection mold according to one embodiment of the present invention.

FIG. 2 is a sectional view showing the same ferrule injection mold.

FIG. 3 is an explanatory diagram of the same operation.

FIG. 4 is a side view showing the same ferrule in cross section.

FIG. 5 is a front view showing the same ferrule.

[Explanation of symbols]

1: ferrule, 1a: tapered portion, 1b: fitting portion, 1
c: flange-like portion, 1d: short cylindrical portion (holding portion), 1f: cylindrical surface portion (holding portion), 1g: pore, 1h: tapered hole portion, 1
i: thick hole, 2: first mold, 3: second mold, 3c: gate, 4: compressor (compressed air supply source), 5: vacuum pump, 6: vacuum pump, 12: thick pin, 12a: Through hole, 13: thin pin, 14a, 14b, 14c: air vent passage, 15a, 15b, 15c, 15d: air vent passage, A: cavity, A1: first cavity, A2: second cavity.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobuyoshi Anagama 2-2-1 Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa Japan Steel Works Co., Ltd. (72) Inventor Koji Sato 1-6-1 Uchisaiwaicho, Chiyoda-ku, Tokyo No. Nippon Telegraph and Telephone Corporation (72) Inventor Shunichi Higashino 1-6-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-4-371905 (JP, A) 5-241041 (JP, A) JP-A-2-16021 (JP, A) JP-A-63-157705 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/36 B29C 45/34

Claims (3)

(57) [Claims] 1. A fitting portion (1) comprising a cylindrical surface having a tapered portion (1a) whose outer diameter gradually decreases toward one end.
b), a flange-like portion (1) having a larger diameter than the fitting portion (1b).
c), the holding portion (1) having a smaller diameter than the flange portion (1c).
d, 1f) are sequentially formed from one end, and a fine hole (1g) and a thick hole (1i) are formed at the center of the ferrule (1) formed concentrically sequentially from one end for ferrule injection molding. A cavity (A) which is divided by a first mold (2) and a second mold (3) and has a gate (3c) between the two molds (2, 3) is a mold. The fitting portion (1b) formed on one of the first mold (2) and the second mold (3) and having the tapered portion (1a) is partitioned, and the fine hole (1) is formed.
g) is formed in the first cavity (A1) in which a thin pin (13) for forming the same is protruded, and is formed in the other of the first mold (2) or the second mold (3), and the flange-shaped portion (1c) is formed. And a holding portion (1d, 1f), a through-hole (12a) capable of receiving the other end of the thin pin (13), and a thick pin (12) for forming the thick hole (1i). A second cavity (A2) protruding from the first cavity (A1).
A vacuum pump (5) is connected to a portion defining the tapered portion (1a) of the air vent passage (1a) for discharging air.
4a, 14b, 14c) are formed, and the through-hole (1
A ferrule injection molding die, characterized in that a compressed air supply source (4) for injecting compressed air from the periphery of the thin pin (13) toward one end is connected to the other end of 2a). 2. A fitting portion (1) comprising a cylindrical surface having a tapered portion (1a) whose outer diameter gradually decreases toward one end.
b), a flange-like portion (1) having a larger diameter than the fitting portion (1b).
c), the holding portion (1) having a smaller diameter than the flange portion (1c).
d, 1f) are sequentially formed from one end, and a fine hole (1g) and a thick hole (1i) are formed at the center of the ferrule (1) formed concentrically sequentially from one end for ferrule injection molding. A cavity (A) which is divided by a first mold (2) and a second mold (3) and has a gate (3c) between the two molds (2, 3) is a mold. The fitting portion (1b) formed on one of the first mold (2) and the second mold (3) and having the tapered portion (1a) is partitioned, and the fine hole (1) is formed.
g) is formed in the first cavity (A1) in which a thin pin (13) for forming the same is protruded, and is formed in the other of the first mold (2) or the second mold (3), and the flange-shaped portion (1c) is formed. And a holding portion (1d, 1f), a through-hole (12a) capable of receiving the other end of the thin pin (13), and a thick pin (12) for forming the thick hole (1i). A second cavity (A2) protruding from the first cavity (A1).
A vacuum pump (5) is connected to a portion defining the tapered portion (1a) of the air vent passage (1a) for discharging air.
4a, 14b, 14c) are formed, and the through-hole (1
At the other end of 2a), air vent passages (15a, 15b, 15c, 15) are provided at locations where the periphery of the thin pin (13), the flange-like portion (1c) and the holding portions (1d, 1f) are partitioned.
A ferrule injection molding die, characterized in that a vacuum pump (6) for discharging air from d) is connected. 3. A compressed air supply source (4) is provided in parallel with the vacuum pump (6), and the compressed air supply source (4) is selectively connected to the through hole (12a) to provide a thin pin (13). The ferrule injection molding die according to claim 2, wherein compressed air can be injected from one side to one end of the mold.