JPH06201949A - Optical connector manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] Insert the optical fiber hole forming pin 42 into the small V groove 24 of the lower mold 20, insert the fitting pin hole forming pin 44 into the large V groove 26, and cover with the upper mold 30. When the resin is press-fitted to make a ferrule, the upper die 30 may be partially hit and the pins 42 and 44 may float from the V grooves 24 and 26. If molding is performed as it is, the positions of the optical fiber holes and the fitting pin holes of the finished ferrule are misaligned. To solve this problem [Structure] Separately pressing pressure is applied to the molding pin 42 for the optical fiber hole and the molding pin 44 for the fitting pin hole, and the resin is press-fitted therein. In this way, the pins 42,
44 are pressed against the bottoms of the V grooves 24 and 26 without any gap. Therefore, during molding, these are not moved by the resin pressure. Therefore, the optical fiber hole and the fitting pin hole of the ferrule can be located at accurate positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a connector for connecting an optical fiber for communication, and more particularly to a method of manufacturing a ferrule thereof.

[0002]

2. Description of the Related Art FIG. 5 shows a plastic ferrule 10 and a metal mold for molding it. The ferrule 10 has a hole 12 for an optical fiber, and a hole 14 for a fitting pin (positioning pin). The mold includes a lower mold 20, an upper mold 30, and a core 40. A plurality of small V-grooves 24 are arranged in a row on the tip 22 of the lower mold 20. There are large V-grooves 26 on both sides of these. A recess 28 is formed behind the tip 22. At the tip of the core 40, there is a molding pin 42 for making the optical fiber hole 12, which is made of thin wire. 44
Is a forming pin for making the fitting pin hole 14, and is made of a wire (metal rod) thicker than the forming pin 42 for the optical fiber hole.

The core 40 is set in the lower mold 20, the optical fiber hole forming pin 42 is inserted in the small V groove 24, the fitting pin hole forming pin 44 is inserted in the large V groove 26, and the upper mold 30 is inserted.
Then, the resin is filled or press-fitted from the inlet 32. When the resin is hardened, it is taken out of the mold and the core 40 and the fitting pin hole forming pin 44 are pulled out, whereby the hollow ferrule 10 is completed. The protrusion 28a at the center of the recess 28 is a portion for forming a window (not shown) on the lower surface of the ferrule 10. From the window, fiber glue is injected inside.

[0004]

In the ferrule, the optical fiber hole 12 and the fitting pin hole 14 must be in the correct positions. For that purpose, at the time of molding, the molding pin 42 for the optical fiber hole is properly inserted in the small V groove 24 and the molding pin 44 for the fitting pin hole is correctly inserted in the large V groove 26 (perfectly contacting the bottom of the V shape. It is necessary to. However, as shown in FIG. 6, the pressing force is not evenly distributed depending on how the upper mold 30 is pressed, so that one-sided contact occurs,
For example, in the same figure, like the molding pin 44 for the fitting pin hole on the left side, the upper mold 30 may not contact. It is also easily conceivable that this phenomenon will occur even when the accuracy of the upper die 30 is insufficient. If molding is performed as it is, the position of each hole of the molded product becomes inaccurate because each molding pin is not in the specified position of the V groove. Further, the fitting pin hole forming pin 44 may move due to the pressure of the resin, and the position of the fitting pin hole 14 of the finished ferrule 10 may be displaced.

[0005]

As shown in a model in FIG. 1, an independent pressing force is applied to each of the optical fiber hole forming pin 42 and the fitting pin hole forming pin 44. , Make sure to press fit the resin.

It is sufficient that this pressing force can be adjusted by at least one system. In Fig. 1, three routes of pushing pressure are shown,
The pushing pressure can be adjusted by only one system in the center or by the systems on both sides, and the number of systems by which the pushing pressure can be adjusted is not limited.

[0007]

[Operation] The upper mold 30 is prevented from hitting one side.
The optical fiber hole forming pin 42 is provided at the bottom of the small V groove 24.
The fitting pin hole forming pins 44 are pressed against the bottoms of the large V-shaped grooves 26 without any gaps. Therefore, since each molding pin is arranged at the specified position, the accuracy of each hole of the molded product is excellent. Also, the pins 42 and 4 are pressed by the resin pressure during molding.
4 is never moved. As a result, the optical fiber hole 12 and the fitting pin hole 14 of the ferrule 10 can be located at accurate positions.

[0008]

EXAMPLE 1 (a) of FIG. 2 is a plan view of the tip of a mold, and its B section is shown in (b). Reference numeral 50 is a pressing member for the fitting pin hole forming pin 44. This is a short round pin made of metal, and is inserted into the hole of the upper mold 30 with such a tightness that it cannot be easily dropped by its own weight but can be moved up and down. When the screw 52 is turned, the screw 52 is pushed down, and the fitting pin hole forming pin 44 is pressed against the bottom of the large V groove 26 without a gap.
Reference numeral 54 is a pressing member for the optical fiber hole forming pin 42. This is a thick plate-like member, and is inserted in the upper mold 30 so as to be movable up and down. When the screw 56 is turned, it is pushed down, and the optical fiber hole forming pin 42 is pressed against the bottom of the small V groove 24 with no gap. If molding is performed in this way, the positions of the optical fiber hole 12 and the fitting pin hole 14 will be accurately inserted into the V groove.

Since the pitch accuracy between the various holes is important in the molding of the optical ferrule, the V groove block on the front surface and the corresponding part of the upper die that holds the V groove block are different from the other parts of the die for forming the cavity. , Separated format is also acceptable.

[0010]

Second Embodiment In the case of FIG. 3, in order to improve the operability (since the die itself is very small, the screw 52 and the like are also small), the sizes of the screws 52 and 56 are increased. Therefore, since it is difficult to arrange them in one horizontal row, the central screw 56 is displaced inward. On the contrary, the central screw 56 may be forward and the screws 52, 52 on both sides may be retracted. The size (diameter) of each screw may be changed. The reason for making them alternate also means that the pressing position on each pin is changed to improve accuracy. The other points are the same as in the case of the first embodiment.

[0011]

Third Embodiment As shown in FIG. 4, a knob 58 is provided on each of the screws 52 and 56 in order to make them easier to turn.
The other points are the same as in the case of the first embodiment.

Although three independent pressing means have been shown above, for example, the pressing means for the optical fiber hole is omitted and only two pressing means for the fitting pins on both sides can achieve the object of the present invention. be able to. As described above, the number of pressing means is not limited.

Instead of the screws 52 and 56, spring pressure, hydraulic pressure, or pneumatic pressure can be used.

[0014]

EFFECTS OF THE INVENTION Since the resin is pressed into the molding pin for the optical fiber hole and the molding pin for the fitting pin hole by applying independent pressing pressure to each other, the molding pin 42 for the optical fiber hole has a small V. The fitting pin hole forming pin 44 is pressed against the bottom of the groove 24 against the bottom of the large V groove 26 without any gap. Therefore, the molding pin 42 for the optical fiber hole and the molding pin 44 for the fitting pin hole are formed by the resin pressure during molding.
Is not moved. The optical fiber hole 12 and the fitting pin hole 14 of the ferrule 10 can be located at accurate positions.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing the principle of the present invention.

FIG. 2 is an explanatory diagram of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of Embodiment 3 of the present invention.

FIG. 5 is an explanatory diagram of a conventional technique.

FIG. 6 is an explanatory diagram of problems in the conventional technology.

[Explanation of symbols]

 10 Ferrule 12 Optical Fiber Hole 14 Fitting Pin Hole 20 Lower Mold 22 Tip 24 Small V Groove 26 Large V Groove 28 Recess 30 Upper Mold 32 Inlet 40 Core 42 Molding Pin for Optical Fiber Hole 44 Molding Pin for Fitting Pin Hole 50, 54 Push member 52, 56 Screw 58 Knob

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunihiko Jimbo 1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Ltd. Sakura Factory

Claims (1)

[Claims] 1. An optical fiber hole forming pin is inserted into a plurality of small V grooves provided at a tip portion of a lower mold, and fitting pin hole forming pins are provided in large V grooves provided on both sides of the small V groove. And forming the above-mentioned various holes in the ferrule molded product by covering the lower mold with the upper mold in such a manner, in the optical connector manufacturing method, the optical fiber hole molding pin and the fitting pin hole molding pin , Each with independent pressure,
Optical connector manufacturing method.