JP2893231B2 - Ferrule for optical connector and manufacturing method thereof - 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 for an optical connector and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a ferrule for a four-core optical fiber ribbon. (A) is a perspective view, (b) is a longitudinal sectional view. 10 is the whole ferrule, and 11 is the main body. Reference numeral 12 denotes a fiber hole, into which an optical fiber (glass portion) enters. 14 is a guide groove, in which
The wire part enters. Reference numeral 16 denotes a terminal hole, into which a covered portion of the core wire is inserted. Reference numeral 18 denotes a window for injecting an adhesive, which is provided at a position facing the guide groove 14. 19 and 19 are guide holes.

[0003] The ferrule 10 is made by transfer molding or injection molding of plastic or ceramics (plastic binder). An example of the mold used for the molding is shown in FIGS. 5 is an exploded perspective view, FIG. 6 is a plan view without the upper mold, and FIG. 7 is a vertical elevation view. Reference numeral 20 denotes the whole mold (FIGS. 5 and 7). this is,
It comprises a lower mold 22, a middle mold 40 and an upper mold 50.

[Lower mold 22] 24 is a cavity (only the lower half is shown in FIG. 5), and 26 is a window piece for forming the window 18 of the ferrule 10. In addition, a U groove 28, a V groove 30, and a V groove 32 are provided.

[About the middle mold 40] 42 is a guide hole pin for forming the guide hole 19 of the ferrule 10. 44 is a terminal forming tool. The main body 440 has a square thick plate shape and forms the terminal hole 16 of the ferrule 10. The tip 442 is half the thickness of the main body 440 and has a semi-round groove on the surface. The tip portion 442 forms the window 18 of the ferrule 10 together with the window piece 26 described above. 4
Reference numeral 6 denotes a fiber hole pin whose tip 460 forms the fiber hole 12 of the ferrule 10. Also its base 4
62 is slightly thicker, the lower half fits into the round groove at the tip 442 of the terminal forming tool 44, and the upper half
Guide groove 14 is formed. The rear part of the base 462 is fitted and held in the main body 440 of the terminal forming tool 44.

[Regarding Upper Die 50 and Die Assembly and Molding] The upper die 50 has a sprue 52. Terminal forming tool 44
Of the lower mold 22 in the U groove 28 (FIGS. 6 and 7). The distal end 460 of the fiber hole pin 46 is
Fit in. The guide hole pin 42 is placed in the V groove 30. Then, the upper mold 50 is covered. Then, molding is performed. After the molding, when the middle mold 40 is removed, the ferrule 10 is completed. If the mold is manufactured with high precision, the position of the fiber hole 12 of the molded ferrule will not be out of order unless the fiber hole pin 46 and the terminal forming tool 44 are deformed.

[0007]

In the conventional mold, as described above, the base 462 of the fiber hole pin 46 is used.
The rear part of the terminal forming tool 44 is held in the main body 440 of the terminal forming tool 44 while the front half of the base 462 is in a state in which the lower half is accommodated in the round groove of the tip 442 of the terminal forming tool 44 ( (FIG. 7). Therefore, when the resin is injected and molded into the cavity 24 and the process of releasing the mold is repeated, the molding material 60 enters the gap between the distal end portion 442 of the terminal forming tool 44 and the fiber hole pin 46 as shown in FIG. Come. Then, the fiber hole pin 46 is deformed, and as a result, the fiber hole 12 of the formed ferrule 10 is inclined. In such a case, as the ferrule joint surface is polished, the fiber hole 12 becomes eccentric with respect to the guide hole 19, which causes a problem in performance.

[0008]

As shown in FIG. 1B, a base 462 of a fiber hole pin 46 and a window piece 26 are provided.
And a gap 62 into which the molding material flows.

[0009] The gap 62 is dimensioned to be positively filled with the molding material. In the case of FIG. 1B, the distal end portion 442 of the conventional terminal forming tool 44 is thinned so that a gap 62 is formed between the terminal forming tool 44 and the fiber hole pin 46. Alternatively, as shown in FIG. 2, the gap 62 may be formed between the fiber hole pin 46 and the window piece 26 by omitting all the distal end portions 442 of the terminal forming tool 44.

When molded by the mold 20 having the above-mentioned gap 62, as shown in FIG. 1 (c), a thin plate-shaped overhang portion 15 is formed in the window 18 at a position away from the bottom of the guide groove 14. State.

When the ferrule is used, it interferes with the injection of the adhesive when the ferrule is used. Therefore, as shown in FIG. 3, the protruding portion 15 is cut off from the main body 11 by the tip of the tool 64 as shown in FIG.

[0012]

The molding material injected into the mold 20 at the time of molding has a low viscosity. If the molding material goes around the gap 62 and the internal pressure of the cavity 24 is constant, the fiber hole pin 46 does not deform. Therefore, the fiber hole 12 of the ferrule 10 is not inclined, so that the performance of the connector is improved and the production yield is increased.

[Brief description of the drawings]

FIG. 1A is a plan view of a mold without an upper mold, FIG. 1B is a longitudinal sectional view of the mold, and FIG.
3 is a longitudinal sectional view of a ferrule manufactured by using the above-described mold.

FIG. 2 is an explanatory view of another example of the mold of the present invention.

FIG. 3 is an explanatory view of a method for removing the overhang portion 15 from the ferrule of the present invention.

FIG. 4 is an explanatory view of a conventional ferrule.

FIG. 5 is an exploded perspective view of a conventional mold.

FIG. 6 is a plan view of a conventional mold excluding an upper mold.

FIG. 7 is a vertical sectional view of a conventional mold.

FIG. 8 is an explanatory diagram of a problem of the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ferrule 11 Main body 12 Fiber hole 14 Guide groove 15 Projection part 16 Terminal hole 18 Window 19 Guide hole 20 Die 22 Lower mold 24 Cavity 26 Window piece 28 U groove 30, 32 V groove 40 Medium size 42 Guide hole pin 44 Terminal Forming tool 440 Body 442 Tip 46 Fiber hole pin 460 Tip 462 Base 50 Upper die 52 Sprue 60 Molding material 62 Gap 64 Tool

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-179406 (JP, A) JP-A-6-59157 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 6/36-6/40

Claims (2)

(57) [Claims] 1. A ferrule having a fiber hole, a guide groove following the fiber hole, and a window opened toward the guide groove, wherein a thin plate-shaped member is provided in the window at a position away from the bottom of the guide groove. An overhang portion is provided,
Ferrule for optical connector. 2. A method of molding a ferrule for an optical connector using a mold having a terminal forming tool, a pin for a fiber hole held at the tip thereof, and a window piece protruding into a cavity. A method for manufacturing a ferrule for an optical connector, wherein the molding is performed using a mold provided with a gap into which a molding material flows between a base of a pin and a window piece.