JP2013015744A - Optical connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow smooth removal of a coating of a coated optical fiber.SOLUTION: A mechanical splicing part for butt joint between a built-in optical fiber and an inserted optical fiber is provided with a coating removal part for removing a coating of a coated optical fiber, and a coating removing member constituting the coating removal part includes a coated optical fiber insertion-side portion having a coated optical fiber insertion hole, and a coating removal-side portion having a bare fiber insertion hole and a coating removing action portion for removing the coating of the coated optical fiber. An inner diameter of the coated optical fiber insertion hole is approximately equal to an outer diameter of the coating of the coated optical fiber, and the bare fiber insertion hole has an intermediate part having an inner diameter approximately equal to an outer diameter of a bare fiber and has, on the entrance side, a taper hole expanded toward the entrance and has, on the exit side, a diameter larger than the outer diameter of the bare fiber. Collisions with an inner wall of the bare fiber insertion hole, of a front end edge of the bare fiber which has had the coating removed therefrom are reduced, and disconnection of the bare fiber due to axial misalignment from a centering groove for butt joint can be prevented.

Description

  According to the present invention, a mechanical splice portion is integrally provided at the rear portion of a ferrule portion that incorporates a built-in optical fiber, and the mechanical splice portion is provided with a coating removing portion that acts to peel off the coating of the coated optical fiber. The present invention relates to an on-site optical connector of mechanical splice type capable of butt connection by pushing.

A technique has been reported in which a coated optical fiber is pushed into an optical connector as it is without being stripped in advance to expose the bare fiber, and butt-connected to the opposing optical fiber (built-in optical fiber) (non-patented) Reference 1). In this report, a coated optical fiber having a bare fiber diameter of 0.125 mm and a coated portion outer diameter of 0.25 mm is targeted.
For this butt connection by pushing the coated optical fiber, as a connection model of the butt portion, a coating removing member having a hole (alignment portion) having an inner diameter of 126 mm in the axial center portion of the cone is used. The coating of the coated optical fiber is peeled off by pressing against the hole tip (insertion end) of the removing member with a force greater than that required for coating removal of the coated optical fiber.
In order to press this thin coated optical fiber against the hole tip of the coating removal member and peel the thin coating without damaging the bare fiber, it is necessary to press the coated optical fiber against the hole tip with extremely high accuracy. Therefore, it is necessary to guide the coated optical fiber to the hole tip with high accuracy.

To realize the coating removal technology by pushing the coated optical fiber as described above, in which the thin coated optical fiber is pressed against the hole tip of the coating removal member and peeled off, in an actual field assembly optical connector, For many parts, it is necessary to devise concrete structures.
For example, the optical connector of Patent Document 1 is not a butt connection type optical connector having a built-in optical fiber, but a bare fiber obtained by removing the coating of the coated optical fiber inserted into the optical connector is inserted into the optical fiber hole of the ferrule part. In this optical connector, the ferrule part is provided with a coating removal part.
That is, the optical fiber holding hole 37 provided in the ferrule part includes a first hole 53 having an inner diameter substantially the same as the outer diameter of the coated optical fiber, and a second hole 55 having an inner diameter substantially the same as the outer diameter of the bare optical fiber. As a configuration including a coating receiving portion 57 provided between the first hole portion 53 and the second hole portion 55, the coated optical fiber 19 can be mounted with the coating.

JP2009-128422

Proceedings 2 of the 2009 IEICE Society Conference “Considerations on Butt Connection of Coated Optical Fiber Cores” (B-13-8).

  As described above, there is an optical connector provided with a coating removal part (Patent Document 1) in which a ferrule part is provided with a coating removal part, but the bare fiber diameter is 0.125 mm, and the coated optical fiber is coated. Since it is not easy to peel off the thin coating of a thin coated optical fiber having an outer diameter of 0.25 mm without damaging the bare fiber inside the thin ferrule part, a coating removal part is provided in the ferrule part. There seems to be various difficulties in putting the structure into practical use.

By the way, if the structure with a mechanical splice part integrated optical connector with a mechanical splice part integrated in the rear part of the ferrule part incorporating the built-in optical fiber is provided with a coating removal part, it is more excellent as a field assembly optical connector. It will be a thing.
However, as described above, it is easy to peel off a thin coating on a thin coated optical fiber having a bare fiber diameter of 0.125 mm and a coated optical fiber outer diameter of 0.25 mm without damaging the bare fiber. Therefore, it is necessary to devise specific structures in various respects in order to provide a mechanical splice unit-integrated optical connector having a coating removal unit therein.
In particular, since the specific structure of the coating removal portion provided in the mechanical splice portion greatly affects the coating removal performance, various devices are required for the structure of the coating removal portion.

  The present invention has been made based on the above-mentioned background, and in the case where the optical splicer integrated with a mechanical splice is configured to have a coating removal portion inside, it is possible to smoothly remove the coating of the coated optical fiber. An object of the present invention is to provide a mechanically-spliced on-site optical connector having a coating removal portion.

According to a first aspect of the present invention, there is provided a mechanical splice type field assembly optical connector of the present invention, wherein a ferrule part including a built-in optical fiber and a rear part of the ferrule part are attached and inserted from the outside with the built-in optical fiber. A mechanical splice part that butt-connects the optical fiber with the coated optical fiber from which the jacket of the optical cable is removed, and a butt connection between the built-in optical fiber and the inserted optical fiber in the mechanical splice part. A coating removing unit provided to remove the coating of the coated optical fiber,
The coating removal member constituting the coating removal unit is
A coated optical fiber insertion side portion having a coated optical fiber insertion hole for guiding the coated optical fiber;
The coated optical fiber is provided in front of the coated optical fiber insertion hole, has a bare fiber insertion hole coaxial with the coated optical fiber insertion hole, and removes the coating of the coated optical fiber at the end of the coated optical fiber insertion hole side. And a coating removal side portion having a coating removal working portion formed with a cylindrical blade for,
The inner diameter of the coated optical fiber insertion hole is substantially the same inner diameter as the outer diameter of the coated optical fiber, and the inner diameter of the intermediate portion of the bare fiber insertion hole is substantially the same as the outer diameter of the bare fiber. ,
A taper hole is formed such that the inlet side is tapered from the intermediate portion having the same inner diameter as the bare fiber outer diameter of the bare fiber insertion hole, and the inner diameter of the outlet side is larger than the inner diameter of the intermediate portion. A mechanical splice type on-site assembly optical connector.
The portion of the bare fiber insertion hole on the inlet side from the intermediate portion that is substantially the same inner diameter as the bare fiber outer diameter is not limited to the case where the whole is a tapered hole. There may be a uniform inner diameter hole having the same diameter as the maximum diameter.

A mechanical splice type field assembly optical connector according to claim 1, wherein
A portion of the bare fiber insertion hole in which the inner diameter on the outlet side is larger than the inner diameter of the intermediate portion is a tapered hole extending to the outlet side.

A mechanical splice type field assembly optical connector according to claim 1 or 2, wherein
The length of the portion having the same inner diameter as the outer diameter of the bare fiber in the bare fiber insertion hole in the coating removal side portion is 0.05 mm to 0.5 mm.

A mechanical splice type field assembly optical connector according to any one of claims 1 to 3,
The coating removal member is formed by integrally molding a coated optical fiber insertion side portion and a coating removal side portion with a molding material.

A mechanical splice type field assembly optical connector according to any one of claims 1 to 4, wherein
The coating removal member is formed by integrally molding a coated optical fiber insertion side portion and a coating removal side portion with a resin.

A mechanical splice type field assembly optical connector according to claim 4 or 5, wherein
The coating removing member is integrally formed with a mold using a single core pin as a core for forming a coated optical fiber insertion hole portion and a bare fiber insertion hole portion.

The mechanical splice type field assembly optical connector according to any one of claims 1 to 6, wherein a gap between the coated optical fiber insertion hole and the bare fiber insertion hole is 0.1 to 0.3 mm. It is characterized by being.

The mechanical splice type field assembly optical connector according to any one of claims 1 to 7,
The sheath removing action portion of the sheath removing member has a cone-shaped portion that is tapered toward the inlet side of the bare fiber insertion hole and the cylindrical blade is formed at the tip of the hole. The side taper angle is 20 ° to 40 °.

A mechanical splice type field assembly optical connector according to any one of claims 1 to 7,
The sheath removing action portion of the sheath removing member has a concavely curved cone-like portion that is tapered toward the inlet side of the bare fiber insertion hole and is tapered to form the cylindrical blade at the tip of the hole. It is characterized by that.

A mechanical splice type field assembly optical connector according to any one of claims 1 to 9,
The space formed between the coated optical fiber insertion hole and the bare fiber insertion hole in the coating removal member is zero on both sides in the radial direction of the bare fiber insertion hole in two directions orthogonal to the bare fiber insertion hole core. A gap of 5 mm or more is formed.

According to the mechanical splice type field assembly optical connector of the present invention, a coated optical fiber insertion side portion having a coated optical fiber insertion hole and a coating removing member for removing the coated optical fiber coating is provided in the mechanical splice portion. And a coating removal side portion having a coating removal working portion in which a cylindrical blade for removing the coating of the coated optical fiber is formed, and has a bare fiber insertion hole,
The inner diameter of the coated optical fiber insertion hole is substantially the same inner diameter as the outer diameter of the coated optical fiber, and the inner diameter of the intermediate portion of the bare fiber insertion hole is substantially the same as the outer diameter of the bare fiber. A taper hole in which the inlet side extends in a taper form from an intermediate part that is substantially the same inner diameter as the bare fiber outer diameter of the bare fiber insertion hole, and the inner diameter of the outlet side is larger than the inner diameter of the intermediate part, Since the inner diameter of both sides is larger than the inner diameter of the middle part of the bare fiber insertion hole, it is easy to insert the bare fiber into the bare fiber insertion hole, and the outer periphery (edge of the tip) of the bare fiber from which the coating has been removed is bare. There is less chance of hitting (contacting) the inner wall of the fiber insertion hole (the probability of hitting is reduced).
In other words, the longer the inner diameter portion that is the same as the outer diameter of the bare optical fiber from which the coating has been removed, the easier it is for the bare fiber from which the coating has been removed to hit the inner wall of the bare fiber insertion hole. By making this part only part of the bare fiber insertion hole, the probability of collision and the distance in case of collision can be shortened.
In addition, by opening the outlet on the side of the aligning groove of the mechanical splice part of the hole including the same inner diameter part as the outer diameter of the bare optical fiber from which the coating is removed, the outer diameter of the bare optical fiber from which the coating is removed is the same. It is possible to suppress the occurrence of a bare fiber breakage (breakage due to an exit hole edge (edge)) due to an axial deviation between the inner diameter portion and the aligning groove portion.
It is preferable that the outlet side is also tapered from the middle portion of the bare fiber insertion hole.
The length Sa of the same inner diameter as that of the bare optical fiber is suitably 0.5 mm or less. However, if the length Sa is too short, the alignment function is impaired. Is appropriate.

According to the fourth aspect, since the coated optical fiber insertion side portion and the coating removal side portion of the coating removal member are integrally formed, the coated optical fiber insertion hole and the coating removal side portion of the coated optical fiber insertion side portion Both cores with the bare fiber insertion hole can be made to coincide with each other with high accuracy, the coating removal can be performed smoothly, and the coating removal performance can be enhanced.
In addition, when attaching the coating removal member to the mechanical splice, it is not necessary to align and fix the coated optical fiber insertion side portion and the coating removal working portion, so that workability is good and high alignment is achieved. It is easy to ensure accuracy.
Moreover, since it is an integrally molded product, it can be mass-produced and the cost can be reduced.
Further, when a single core pin is used as a core for forming the coated optical fiber insertion hole portion and the bare fiber insertion hole portion, the coated optical fiber on the coated optical fiber insertion side portion is formed. Both hole cores of the insertion hole and the bare fiber insertion hole on the coating removal side portion can be matched with higher accuracy.

According to the seventh aspect, since the gap dimension a between the coated optical fiber insertion hole and the bare fiber insertion hole is set to 0.1 to 0.3 mm, the function of removing the coating of the coated optical fiber is made effective. Can be fulfilled.
That is, if the gap a is long, the coated optical fiber is buckled and the coating cannot be removed. Further, if the gap a is too short, the rigidity of the coating is substantially increased. Therefore, there is a limit to the sharpness of the blade of the coating removing member, so that the coating does not break and is similar to a corrugated pipe along the bare fiber. There is a risk of slipping. However, when the appropriate gap size is 0.1 to 0.3 mm, the coating can be removed smoothly without causing such a phenomenon, and the function of removing the coating of the coated optical fiber is effective. Can be fulfilled.

In Claim 8, the coating removal action part of a coating removal member has the cone-shaped part by which a cylindrical blade is formed in the front-end | tip. If the taper angle of the side surface of this cone-shaped portion is about 10 ° or less, the cutting edge of the cylindrical blade becomes too thin and the strength is weakened and easily breaks. The sharpness of the blade edge becomes dull, and the pushing force (coating removal force) required for removing the coating increases. However, when the taper angle of the side surface of the cone-shaped portion is in the range of 20 ° to 40 °, it is possible to reduce the pushing force required for removing the coating while securing the strength.
Further, when the side surface of the cone-shaped portion is concavely curved toward the tip as in the ninth aspect, the thickness of the blade edge of the cylindrical blade becomes thicker as it goes away from the edge. Therefore, a cylindrical blade having both sharpness and strength can be obtained.
In addition, since the side surface of the cone-shaped part is concavely curved, the action of spreading the cylindrical coating cut by the cutting edge of the cylindrical blade along the side surface of the concave curved surface becomes large, and the cylindrical coating is cracked. Since the coating waste is easily split into a plurality of pieces, the action of peeling the coating waste from the bare fiber is effectively performed. That is, there is an effect of preventing the coating from sliding along the bare fiber in a state like a corrugated pipe. Thereby, the coating removal performance is improved.
In addition, since the coating is easily split into a plurality of pieces and decomposed into a plurality of pieces, it becomes easy to store the covering waste.
Further, when the pyramidal portion is formed into a pyramid shape, the covering is easily split into a plurality at the edge portion of the pyramid ridgeline.

  According to the tenth aspect, the space formed between the coated optical fiber insertion hole and the bare fiber insertion hole of the coating removal member has two directions (substantially the thickness direction and width) perpendicular to the bare fiber insertion hole core. Direction), both have a gap of 0.5 mm or more on both sides in the radial direction of the bare fiber insertion hole, so that a space for storing the covering waste can be secured. Thereby, the coating removal length can be increased.

It is a perspective view of one Example of the mechanical splice type field assembly optical connector of the present invention, and is a figure showing the situation where an optical connector is attached to an optical fiber with a covering of an optical cable using a pushing auxiliary jig and a wedge member. In FIG. 1, it is the perspective view shown except the pushing auxiliary | assistance jig | tool and the wedge member. (A) is a plan view of FIG. 2, (b) is the same front view, and (c) is the same bottom view. It is the figure which abbreviate | omitted and simplified and showed the longitudinal cross-section of the said optical connector. It is a perspective view of the plug frame in the optical connector. 5A and 5B show details of the plug frame of FIG. 5, where FIG. 5A is a plan view, FIG. 5B is a front view, FIG. 5C is a cross-sectional view taken along line AA in FIG. B sectional drawing, (e) is B'-B 'sectional drawing of (a). It is a perspective view of the stop ring in the above-mentioned optical connector. 7A and 7B show details of the stop ring of FIG. 7, (a) is a plan view, (b) is a front view, (c) is a bottom view, (d) is a cross-sectional view taken along the line CC in (a), (B) is a DD sectional view of (b), (f) is a left side view of (b), and (g) is a right side view of (b). It is a perspective view of the movable guide in the said optical connector. 9A and 9B show details of the movable guide of FIG. 9, (a) is a front view, (b) is a plan view, (c) is a bottom view, (d) is a left side view of (a), and (e) is ( It is a right view of a). It is EE sectional drawing of FIG.10 (b). The detail of the base part of the mechanical splice part which is a member inside the said optical connector is shown, (a) is a front view of a base part, (b) is the same top view, (c) is F- of (a). F sectional drawing, (d) is a right view of (b), (e) is GG sectional drawing of (a). 12A and 12B show open guides attached to the base portion of FIG. 12, where FIG. 12A is a bottom view (a view corresponding to FIG. 12C), FIG. 12B is a view of FIG. FIG. 3 is a left side view enlarged twice as much as (a). It is a figure which shows the state which attached | attached the cover, the movable guide, and the coating | coated removal member to what fixed the ferrule to the base part of Fig.12 (a) with a wedge member. (A) is the figure which expanded FIG.12 (d), (b) is the right view of FIG. It is the perspective view which showed the jacket holding member in FIGS. 1-3 in the state which opened the cover body. FIG. 15 is an enlarged view of the coating removing member in FIG. 14, (a) is a perspective view, and (b) is a plan view illustrating a situation where the coating of the coated optical fiber is removed. FIG. 17 shows a detailed structure of the coating removing member shown in FIG. 16, wherein (a) is a plan view, (b) is a left side view, (c) is a right side view, and (d) is a KK of (a). Sectional drawing and (e) are JJ sectional drawings of the principal part of (d). (A), (b), (c) explains the taper angle of the side surface when the cone-shaped portion of the sheath removal member is a cone-shaped portion, (a), when the angle θ is 40 °, (B) is the case where the angle θ is 20 °, and (c) is the case where the side surface of the conical portion is a concave curved surface. (D), (e), (f) is a diagram (a diagram corresponding to FIG. 21 (e)) of the pyramid-shaped portion viewed from the front when the pyramidal-shaped portion is a pyramid-shaped portion; ) Is when the pyramid-shaped portion is a quadrangular pyramid-shaped portion, (e) is when the side surface of the quadrangular pyramid-shaped portion of (d) is a concave curved surface, and (f) is when the pyramid-shaped portion is a triangular pyramid shape. It is a case and the side surface is a concave curved surface. The modification about the shape of the bare fiber penetration hole of the coating removal side part 45 in a coating removal member is shown, (a) is a top view of a coating removal member, (b) is a left view, (c) is a right side FIG. 4D is an LL cross-sectional view of FIG. FIG. 24 is a sectional view showing another modification of the shape of the bare fiber insertion hole of the coating removal side portion 45 in the coating removal member and corresponding to FIG. 23D of the coating removal member. FIG. 2 schematically shows a mold for integrally molding the above-described coating removal member with resin, (a) is a cross-sectional view showing a state in which the upper mold and the lower mold of the mold are combined (the core pin is not shown); (B) is a top view (what showed the core pin in the MM arrow line view) which shows the state which has arrange | positioned the core pin in the lower mold | type of (a).

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a mechanical splice type field assembly optical connector embodying the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a mechanical splice type field assembly optical connector 1 according to an embodiment of the present invention. The mechanical splice type field assembly optical connector 1 is pushed into a coated optical fiber 5 of an optical cable 4 and an auxiliary jig 14 and It is a figure which shows the condition attached using the wedge member. 2 is a perspective view of FIG. 1 excluding the pushing assist jig 14 and the wedge member 15, FIG. 3 (a) is a plan view of FIG. 2, (b) is the front view thereof, and (c) is the bottom view thereof. FIG. FIG. 4 is a longitudinal sectional view showing an outline of the internal structure of the above-mentioned mechanical splice type field assembly optical connector 1, and a part thereof is omitted and simplified.

This mechanical splice type field assembly optical connector (hereinafter also simply referred to as an optical connector) 1 is integrally attached to a ferrule part 3 having a built-in optical fiber (bare fiber) 2 and a rear part of the ferrule part 3. Then, the built-in optical fiber 2 and the inserted optical fiber (indicated by reference numeral 6 in FIG. 17) from which the coating 5a of the coated optical fiber 5 from which the jacket 4a of the optical cable 4 inserted from the outside is removed are butt-connected. A mechanical splice portion 7, and a plug frame 9 that accommodates a mechanical splice portion integrated ferrule portion 8, in which the ferrule portion 3 and the mechanical splice portion 7 are integrated, with a forward limit thereof slidably moved back and forth. The mechanical splice 7 is fixed to the plug frame 9 and is moved forward through a C-shaped leaf spring 26. A stop ring 10 for biased, and a jacket gripping member 11 for gripping the envelope 4a of the optical cable 4 with the connector rear end.
The outer diameter of the coated portion of the coated optical fiber 5 is 0.25 mm, and the outer diameter of the bare fiber from which the coating is removed is 0.125 mm.

5 is a perspective view of the plug frame 9, FIG. 6A is a plan view of the plug frame 9, FIG. 5B is a front view, FIG. 5C is a cross-sectional view taken along line AA in FIG. a) BB sectional drawing of (a), (e) is B'-B 'sectional drawing of (a).
As described above, the plug frame 9 accommodates the mechanical splice unit integrated ferrule unit 8 so as to be slidable back and forth with its advance limit, and slides on the flange 8a of the mechanical splice unit integrated ferrule unit 8. It has a cylindrical inner surface 9a to be fitted, and a forward limit is defined by a step 9b at the tip. Further, it has a cylindrical inner surface 9 c into which the cylindrical portion 10 a on the front side of the stop ring 10 is fitted. 9d is a locking portion that engages with a hole formed in the side surface of the cover 13 to lock the cover 13, and 9e is a locking portion that engages with the engagement protrusion 10b of the stop ring 10 to lock the stop ring 10. Part. 9 f is a hole through which the insertion piece 15 a of the wedge member 15 passes.
The cover 13 is attached to the portion of the plug frame 9 and has an outer shape that matches the shape of the inner surface of the adapter that is inserted when the optical connector is connected. The shape of the cover and the shape of the plug frame vary depending on the type of connector.

7 is a perspective view of the stop ring 10 in the optical connector, FIG. 8 (a) is a plan view of the stop ring 10, (b) is a front view, (c) is a bottom view, and (d) is C in (a). -C sectional drawing, (e) is DD sectional drawing of (b), (f) is a left view of (b), (g) is a right view of (b).
As described above, the cylindrical portion 10a of the stop ring 10 is fitted into the plug frame 9 and locked by the engaging projection 10b, and the mechanical splice portion 7 is elastically biased forward via the coil spring 27. To do. On the rear end side opposite to the cylindrical portion 10a, there is a space 10c ′ surrounded by a U-shaped frame portion 10c that houses a coated optical fiber guiding portion 24 of the movable guide 21 described later. A groove 10e for guiding the movable guide 21 is provided on the inner surface of both side walls 10d of the U-shaped frame portion 10c. 10 f is a hole through which the insertion piece 15 a of the wedge member 15 passes.
On the top of the stop ring 10, the lever 12 for restraining the outer cover gripping member 11 from falling off is attached rotatably by a hinge shaft 12a.

A cylindrical portion 22 of the movable guide 21 shown in FIGS. 9 to 11 is inserted into the stop ring 10. 9 is a perspective view of the movable guide 21, FIG. 10A is a front view of the movable guide, FIG. 9B is a plan view, FIG. 9C is a bottom view, FIG. 9D is a left side view of FIG. ) Is a right side view of (a). FIG. 11 is a cross-sectional view taken along line EE in FIG.
Although the details will be described later, the movable guide 21 is coated with the pressing force during the coating removal, in which the coated optical fiber 5 is pressed against the coating removing member 20 shown in FIGS. 14 and 17 to remove the coating 5a. This is a member that constitutes a part of the coated optical fiber holding structure for securing the allowable gap m in the optical fiber length direction such that the attached optical fiber 5 does not buckle. The allowable gap m is about 2.1 mm.
The movable guide 21 includes a cylindrical portion 22 having a cylindrical outer peripheral surface. The cylindrical portion 22 is covered with the mechanical splice portion 7, and the cylindrical outer peripheral surface of the cylindrical portion 22 is slid into the stop ring 10. It is movably fitted and is movable in the front-rear direction with respect to the mechanical splice part 7.
This movable guide 21 is integrally provided with a coated optical fiber guiding portion 24 having a substantially square shape for introducing the coated optical fiber 5 at the rear end of the cylindrical portion 22. As shown in FIG. 11, the coated optical fiber guiding portion 24 includes a coated optical fiber insertion hole 24b having an inner diameter slightly larger than the coated optical fiber diameter at the tip of the conical guide surface 24a. .
The cylindrical hollow portion 23 of the cylindrical portion 22 extends to the inside of the coated optical fiber guiding portion 24, and has a vertical inner wall 24c at the abutting portion of the coated optical fiber guiding portion 24. As will be described later, the vertical inner wall 24c pushes the rear end surface of the opening guide 31. The movable guide 21 that is pushed forward by the outer gripping member 11 stops when the vertical inner wall 24c hits the rear end surface of the mechanical splice portion 7. At this time, since the protrusion 30f provided on the base portion 30 of the mechanical splice portion 7 enters the locking hole 22b provided on the movable guide 21, the movable guide 21 does not retract from the position.
The conical guide surface 24a and the coated optical fiber insertion hole 24b of the coated optical fiber guiding portion 24 are partially formed by the guide surface 25a and the partial hole surface 25b of the movable piece 25. FIG. 9 shows the movable piece 25 removed.
A groove 24d through which an arm 50 (described later) of the jacket holding member 11 passes is formed on the side surface of the coated optical fiber guiding portion 24. 22a is a hole through which the insertion piece 15a of the wedge member 15 passes. There are other holes (openings).
Although the detailed description of the lock lever 35 shown in FIG. 10 is omitted, the movable guide 21 is set at a predetermined position where the outer cover holding member 11 holding the outer cover of the optical cable 4 is advanced. Thus, when the coated optical fiber 5 is advanced, the lock for restricting the advancement of the movable guide 21 to the appropriate timing so that the outer gripping member 11 moves the movable guide 21 forward at the appropriate timing. Has function.

12A and 12B show details of the mechanical splice portion 7 in the optical connector 1. FIG. 12A is a front view of the base portion 30 of the mechanical splice portion 7, FIG. 12B is a plan view thereof, and FIG. FF sectional drawing of (b), (d) is a right view of (b), (e) is GG sectional drawing of (a). FIGS. 13A and 13B show the open guide 31 attached to the base portion of FIG. 12, where FIG. 13A is a bottom view (a view corresponding to FIG. 12C), and FIG. 13B is a view of FIG. , (D) is a left side view enlarged twice as large as (a).
The mechanical splice portion 7 includes a base portion 30, a lid portion 33 that covers the base portion 30, a C-shaped leaf spring that elastically clamps the base portion 30 and the lid portion 33, and a lid for the base portion 30. The alignment surface 10c with the portion 33 is provided with an alignment groove 32a for accommodating the built-in optical fiber 2 and the insertion optical fiber 6 and a covering portion receiving groove 32b for accommodating the portion of the coated optical fiber 5 in a straight line. It is. Further, a recess 30a for mounting the coating removing member 20 is provided between the coating portion receiving groove 32b and the alignment groove 32a. _{30b (30b 1, 30b 2,} 30b 3, 30b 4) is a wedge insertion portion which wedge member 15 is inserted. The portions other than the wedge insertion portion 30 b are raised portions 30 d that are raised from the mating surface 30 c of the base portion 30. In addition, oblique ridges 30 e that act to move the open guide 31 obliquely are provided on the mating surface 30 c of the base portion 30.

As shown in FIG. 13, the open guide 31 has a notch 31 a having a circular arc part and a straight part for gripping the coated optical fiber 5 at a corner part of a substantially rectangular cross section. There is an oblique groove 31b that fits into the oblique protrusion 30e of the mating surface 30c.
FIG. 14 shows a state in which a cover 33, an opening guide 31, and a sheath removing member 20 are mounted on the base 30 of the mechanical splice unit integrated ferrule unit 8 in which the ferrule unit 3 is integrated with the mechanical splice unit 7 of FIG. It is a figure simplified and shown with the wedge member. The movable guide 21 is indicated by a two-dot chain line.

  FIG. 15A is an enlarged view of FIG. 12D, and FIG. 15B is a view showing the state in which the opening guide 31 and the lid 33 are attached to FIG.

As shown in FIGS. 17 and 18, the coating removing member 20 that removes the coating of the coated optical fiber has a resin integrated molding in which a through space 40 is formed at a position near the front of a thin rectangular parallelepiped in the illustrated example. A coated optical fiber insertion side portion 44 having a coated optical fiber insertion hole 42 for guiding the coated optical fiber 5, and a coated optical fiber insertion hole 42 provided in front of the coated optical fiber insertion hole 42. A sheath removing action portion having a bare fiber insertion hole 41 coaxial with the hole 42 and a cylindrical blade 43a for removing the coating of the coated optical fiber 5 at the end of the coated optical fiber insertion hole 42 side. And a coating removal side portion 45 having 43.
The inner diameter D of the coated optical fiber insertion hole 42 is substantially the same as the outer diameter of the coated portion of the coated optical fiber 5, and the inner diameter d of the bare fiber insertion hole 41 is substantially the same as the outer diameter of the bare fiber 6. It is. The coated optical fiber insertion hole 42 extends in a tapered shape in which the portion on the inlet side of the portion having the same inner diameter D as the coated portion outer diameter of the coated optical fiber 5 faces the inlet side.
By coating the coated optical fiber 5 through the coated optical fiber insertion hole 42 against the tip end portion (that is, the cylindrical blade) 43a of the coating removing action portion 43, the coating of the coated optical fiber 5 is made from the bare fiber. Remove as if peeled off.
The coating 5a is removed from the bare fiber 6 by, for example, tearing in the length direction of the optical fiber at a few locations in the circumferential direction. As shown in FIG. 17B, the coating (covering waste) 5a ′ to be removed is not removed from the coating 5a of the coated optical fiber 5, but is connected to the coating 5a of the coated optical fiber 5 at the root portion. In this state, it is peeled off from the bare fiber 6.

FIG. 18 shows the dimensions of each part of the coating removal member 20. The width W of the coating removal member 20 is about 2.0 mm, the length L is about 3.3 mm, the thickness T is about 1.0 mm, and the height h of the coating removal portion (conical portion) 43 is about 0.3 mm. The length m of the bare fiber insertion hole 41 is about 1 mm, the width w of the void 40 is about 0.7 mm, and the like.
Among these dimensions, it is appropriate that the clearance a between the coated optical fiber insertion hole 42 and the bare fiber insertion hole 41 is 0.1 to 0.3 mm.
If the gap a is long, the coated optical fiber will buckle and the coating cannot be removed. If the gap a is too short, the rigidity of the coating is substantially increased. Therefore, the coating removal member 20 is a resin molded product, and the sharpness of the blade is limited. There is a risk of slipping like a corrugated pipe. However, when the appropriate gap size is 0.1 to 0.3 mm, the coating can be removed smoothly without causing such a phenomenon, and the function of removing the coating of the coated optical fiber is effective. Can be fulfilled.

  The coating removal action part 43 of the coating removal member 20 has a conical shape protruding from the front wall surface 40a of the void 40 to the coated optical fiber insertion hole 42 side. The thickness is extremely reduced with respect to the inner surface to form the cylindrical blade 43a. That is, the cylindrical blade 43a is formed at the tip of the hole so as to taper toward the inlet side (rear end side) of the bare fiber insertion hole 41. A cone-shaped portion protruding from the front wall surface 40a of the void 40, that is, the cone-shaped portion 43 is the covering removal working portion.

FIG. 19 shows various aspects of the side surface of the cone-shaped portion 43 which is a coating removing action portion.
The cone-shaped part 43 in FIGS. 17, 18 and 19A and 19B is a cone-shaped part.
It is appropriate that the taper angle θ of the side surface of the cone-shaped portion 43 is 20 ° to 40 °. FIG. 19A shows the taper angle θ = 40 °, and FIG. 19B shows the taper angle θ = 20 °.
If the taper angle of the side surface of the cone-shaped portion 43 is about 10 ° or less, the cutting edge of the cylindrical blade 43a becomes too thin and the strength is weakened and easily damaged. The sharpness of the cutting edge of the blade 43a becomes dull, and the pushing force (coating removal force) necessary for removing the coating increases. However, when the taper angle θ of the side surface of the cone-shaped portion 43 is in the range of 20 ° to 40 °, it is possible to reduce the pushing force required for removing the coating while securing the strength.

The cone-shaped portion 43 shown in FIG. 19C has a shape in which the side surface of the tapered cone-shaped portion is concavely curved toward the tip. Thus, if the side surface of the cone-shaped part 43 is made into a concave curved surface, it will become thick as it leaves | separates from a blade edge, even if it thins at the blade edge of the cylindrical blade 43a. Therefore, a cylindrical blade having both sharpness and strength can be obtained. In the illustrated example, the taper angle θ at the tip is 20 °.
In addition, since the side surface of the cone-shaped portion 43 is concavely curved, the action of spreading the cylindrical coating cut by the cutting edge of the cylindrical blade 43a along the side surface of the concave curved surface becomes large, and the cylindrical coating is made. Since it becomes easy to crack and the coating waste is easily split into a plurality of pieces, the effect of peeling the coating waste from the bare fiber is effectively performed. That is, there is an effect of preventing the coating from sliding along the bare fiber in a state like a corrugated pipe. Thereby, the coating removal performance is improved.
In addition, since the coating is easily split into a plurality of pieces and decomposed into a plurality of pieces, it becomes easy to store the covering waste.

The cone-shaped part 43 of FIG.19 (d) is a quadrangular pyramid shape. Thus, when the pyramidal portion 43 is formed into a pyramid shape such as a quadrangular pyramid shape, the covering is easily split into a plurality at the edge portion of the ridgeline of the pyramid.
The cone-shaped part 43 of FIG.19 (e) is a quadrangular pyramid shape, and is making the side surface concavely curved. Moreover, the cone-shaped part 43 of FIG.19 (f) is a triangular pyramid shape, and is making the side surface concavely curved. With such a shape, the effect of tearing the coating by the edge portion of the ridge line is improved, and the coating is easily decomposed into a plurality of parts at an early stage.

As described with reference to FIG. 18, the coating removing member 20 has a thin rectangular parallelepiped shape with a thickness T = about 1.0 mm, and has a through space 40 at the front side. Bare fiber insertion hole 41 is provided on the front side, and coated optical fiber insertion hole 42 is provided on the rear side. That is, the space formed between the bare fiber insertion hole 41 and the coated optical fiber insertion hole 42 has a gap dimension n of 0.5 mm on both sides in the thickness direction sandwiching the bare fiber insertion hole core of the coating removal member 20. It is. Further, the gap dimension n on both sides in the width direction sandwiching the bare fiber insertion hole core of the coating removing member 20 is also 0.5 mm.
The gap dimension n is 0.5 mm in the embodiment, but is preferably larger (0.5 mm or more). That is, the space formed between the coated optical fiber insertion hole 42 and the bare fiber insertion hole 41 in the coating removal member 20 is bare in two directions (thickness direction and width direction) perpendicular to the bare fiber insertion hole core. It is desirable to form a gap of 0.5 mm or more on both sides in the radial direction of the fiber insertion hole 41. Although there is no functional upper limit for the gap dimension n, the covering removal member 20 needs to be mounted compactly on the base part 30 of the mechanical splice part 7, so there is an actual upper limit from that surface.
If the space formed between the coated optical fiber insertion hole 42 and the bare fiber insertion hole 41 is a space where gaps n of 0.5 mm or more are formed on both sides in the thickness direction of the coating removal member 20, respectively, A space for storing the waste can be secured, and thereby, the coating removal length (strip length) can be increased. In this embodiment, a strip length of 4 mm is assumed. In addition, the base part 30 shown to Fig.12 (a), (c) is provided with the recess 30f for accommodating a coating waste.

FIG. 20 shows a modification of the diameter of the bare fiber insertion hole.
The bare fiber insertion hole 141 of the sheath removing member 120 is tapered holes 141b and 14c in which the front and rear (exit side and inlet side) of the portion 141a having the same inner diameter as the bare fiber outer diameter are tapered. The tapered hole on the outlet side is denoted by 141b, and the tapered hole on the inlet side is denoted by 14c.
For example, the length Sa of the inner diameter portion 141a having the same outer diameter as the bare fiber is 0.1 mm, the length Sb of the outlet side tapered hole 141b is 0.7 mm, and the length Sc of the tapered hole 14c on the inlet side is 0.2 mm. (Note that the ratio is not shown in the figure).
Thus, if the tapered holes 141b and 14c that taper forward or backward are provided at the front and rear of the portion 14a having the same inner diameter as the bare fiber outer diameter of the bare fiber insertion hole 141, respectively, the coating is removed. In addition, the outer periphery of the tip of the bare fiber 6 does not hit (contact) the inner wall of the bare fiber insertion hole 141 (the probability of hitting becomes small).
That is, the longer the inner diameter portion that is the same as the outer diameter of the bare optical fiber 6 from which the coating is removed, the easier it is for the bare fiber 6 from which the coating has been removed to hit the inner wall of the bare fiber insertion hole. By making the portion 141a having the same inner diameter as the outer diameter of the fiber only a part of the bare fiber insertion hole 141, the probability of collision and the distance in the case of collision can be shortened. Also, if it is short, it is less affected by dust. In addition, the force required for insertion into the bare fiber insertion hole 141 can be reduced.
Further, the outlet side (mechanical splice alignment groove side) of the bare fiber insertion hole 141 is expanded in a tapered shape (tapered hole 141b), so that the inner diameter portion 141a is the same as the outer diameter of the bare optical fiber from which the coating has been removed. And the occurrence of a bare fiber breakage (breakage due to the edge (edge) p of the exit hole) due to the misalignment of the alignment groove (alignment groove 32a shown in FIGS. 4, 12, and 14) can be suppressed.
In this case, if the length of the portion 141a having the same inner diameter as the bare fiber outer diameter in the bare fiber insertion hole 141 of the coating removing action portion 43 is too short, the alignment function is impaired. Is appropriate.
In addition, it is good also considering the exit side part from the intermediate part 141a of the bare fiber penetration hole 141 as a uniform internal diameter hole larger diameter than the internal diameter of the intermediate part 141a instead of the taper hole 141b.

FIG. 21 shows another modification of the diameter of the bare fiber insertion hole.
The bare fiber insertion hole 141 ′ of the sheath removing member 120 ′ also has tapered holes 141 b ′ and 14 c ′ in which the front and back of the portion 141 a ′ having substantially the same inner diameter as the bare fiber outer diameter are tapered. The tapered hole 14c ′ is formed as a portion following a hole 141d ′ having a uniform inner diameter larger than the outer diameter of the bare fiber provided on the inlet side.
In this case, for example, the length Sa of the inner diameter portion 141a ′ that is the same as the outer diameter of the bare fiber is 0.1 mm, the length Sb of the tapered hole 141b ′ on the outlet side is 0.2 mm, and the length of the tapered hole 141c ′ on the inlet side Sc can be 0.1 mm, and the length of the large-diameter uniform inner diameter hole 141d ′ can be 0.6 mm.
In this embodiment, the tapered hole 141b 'on the outlet side is short, and the inner diameter portion 141a' having the same outer diameter as the bare fiber is close to the front alignment groove 32a. Therefore, the inner diameter portion 141a 'having the same outer diameter as the bare optical fiber is used. And misalignment between the alignment groove 32a and the alignment groove 32a.

FIG. 22 shows a simplified example of a mold for integrally molding the coating removing member 20 shown in FIGS. 17 and 18 with resin.
When the coated optical fiber insertion side portion 44 and the coating removal side portion 45 of the coating removal member 20 are integrally molded with this mold 70, an upper die 71 and a lower die that form cavities that match the outer shape of the coating removal member 20 are formed. One core pin 73 is disposed between the mold 72 as a core that forms the coated optical fiber insertion hole 42 and the bare fiber insertion hole 41. The portions corresponding to the voids 40 of the coating removing member 20 are provided with raised portions 71a and 72a corresponding to the contours of the voids 40 that are raised from the bottom surfaces of the upper die 71 and the lower die 72, respectively.
As described above, when the resin is integrally formed with the mold 70 using the single core pin 73 as a core for forming the coated optical fiber insertion hole 42 and the bare fiber insertion hole 41, the coated optical fiber insertion is performed. Both cores of the coated optical fiber insertion hole 42 of the side portion 44 and the bare fiber insertion hole 41 of the coating removal side portion 45 can be made to coincide with each other with high accuracy, and the coating removal can be performed smoothly. Performance can be increased.
When this coating removal member 20 is mounted on the mechanical splice portion, it is not necessary to align and fix the coated optical fiber insertion side portion and the coating removal portion, so that workability is good and high alignment accuracy is achieved. Can be secured.
Moreover, since it is a resin integrated molded product, it can be mass-produced and the cost can be reduced.
As the resin material, a material having a small coefficient of thermal expansion, high strength, high fluidity and high fluidity during resin molding is preferable. For example, PPS (polyphenylene sulfide), LCP (liquid crystal polymer) Etc. can be used.

FIG. 16 is a perspective view showing a state in which the cover of the outer cover holding member 11 is opened.
The outer gripping member 11 includes a gripping member main body 51 and a lid 53 attached to the gripping member main body 51 via a hinge portion 52 so as to be openable and closable. Further, an arm 50 provided with an engaging claw 50a for engaging with the movable guide 21 is provided.
The gripping member main body 51 is integrally provided with a jacket gripping portion 55 for gripping the jacket portion of the optical cable 4 and a covering gripping portion 56 for gripping the coating portion of the coated optical fiber 5. A jacket grip portion 57 that grips the jacket portion and a covering grip portion 58 that grips the coating portion of the coated optical fiber 5 are integrally provided. That is, the jacket portion of the optical cable 4 and the coated portion of the coated optical fiber 5 are held by the integral member.
The outer gripping portion 55 of the gripping member main body 51 has a deep U-shaped frame portion 61 that matches the outer diameter of the optical cable 4 that is a drop cable having a generally rectangular cross-section outer jacket, and this U-shaped frame portion. A longitudinal projection 62a having a triangular cross section is provided on the inner surface of the left and right side walls 62 of the 61, and a small projection is provided on the bottom.
The covering portion 57 of the lid 53 includes a ceiling portion 65 that covers the U-shaped frame portion 61 of the holding member main body 51 and a locking hole that is locked to a locking projection 61 a provided on the U-shaped frame portion 61. It consists of a locking portion 66 having 66a and has a right angle.
A conical protrusion 65 a is provided on the inner surface of the ceiling portion 65 of the lid 53.
The covering grip portion 56 on the grip member main body 51 side has a positioning groove 67a on the upper surface thereof, which is a V groove in the illustrated example in which the coated optical fiber 5 is accommodated.
In addition, the metal mold | die which shape | molds a coating removal member is not necessarily limited to the metal mold | die by one core pin.
In addition, it is preferable to use a resin as the molding material, but it is also possible to use a ceramic such as zirconia.

The work procedure and operation when assembling the mechanical splice type field assembly optical connector 1 will be described.
(1) The sheath 4a of the optical cable 4 is deleted by an appropriate length such as 5 cm to expose the coated optical fiber 5.
(2) Next, after the jacket portion of the optical cable 5 is accommodated in the U-shaped frame portion 61 of the jacket gripping member 11 with the lid 53 opened, the lid 53 is closed and the jacket of the optical cable 4 is gripped. The coated optical fiber 5 is accurately cut to a predetermined length with an optical fiber cutter.
(3) Insert the lid 33 elastically attached to the base part 30 of the mechanical splice part 7 with a C-shaped leaf spring, the insertion piece 15a of the wedge member 15 into the wedge insertion part 30b of the mechanical splice part 7 Keep it open.
(4) At this stage, the movable guide 21 is set at a predetermined position that is positioned by the lock lever 35, and is in a state of not moving forward.
(5) The coated optical fiber 5 of the optical cable 4 gripped by the jacket gripping member 11 is inserted into the movable guide 21 and inserted into the coating portion receiving groove 32b of the mechanical splice portion 7, and the jacket gripping member 11 is It advances and feeds along the coating | coated part accommodation groove | channel 32b. At that time, the outer gripping member 11 is moved forward by being placed on a pushing assist jig 14 attached to the rear end portion of the optical connector 1.
(6) When the jacket holding member 11 is pushed further forward, the tip surface of the coated optical fiber 5 hits the tip surface portion (cylindrical blade) 43a of the sheath removing action portion 43 of the sheath removing member 20 (when this hits) Then, when the coated optical fiber 5 is pushed in, the coated bare fiber 6 is peeled off from the bare fiber by the cylindrical blade 43a of the coat removing action portion 43, and the bare bare fiber 6 is exposed to the bare fiber insertion hole. It passes through 41 and advances in the alignment groove 32a for bare fiber of the mechanical splice part 7. At this time (at this forward stage), the outer gripping member 11 hits the movable guide 21 (the point of contact is called the point B).
The outer covering member 11 and the movable guide 21 are moved together.
(7) From the time point A in the process of pushing in the jacket gripping member 11 (the time point when the front end surface of the coated optical fiber 5 hits the front end surface 43a of the coating removing action portion 43 of the coating removing member 20) B During the time (when the outer gripping member 11 hits the movable guide 21), the operation of the distal end of the arm 50 of the outer gripping member 11 pressing the lock lever 35 to move the lock lever 35 away from the side surface of the movable guide 21. With this operation, the lock lever 35 that restricts the forward movement of the movable guide 21 is unlocked, and the movable guide 21 can move forward.
(8) When the outer cover holding member 11 is pushed further forward, the vertical inner wall 24c of the coated optical fiber guiding portion 24 of the movable guide 21 that moves forward integrally with the outer cover holding member 11 is formed by the open guide 31 of the mechanical splice portion 7. It hits (contacts) the rear end face, and the opening guide is activated.
(10) When the jacket holding member 11 is further pushed forward, the coating removal (peeling) of the coated optical fiber 5 further proceeds while the bare fiber (inserted optical fiber) 6 is in the aligning groove 32a of the mechanical splice portion 7. And a predetermined butt pressure is generated (at the next moment when it is struck). The pushing force when removing the coating is 5N or less.
(11) When the outer gripping member 11 and the movable guide 21 are further pushed in, the open guide 31 pushed by the movable guide 21 is oblique to the base portion 30 of the mechanical splice portion 7 in which the oblique concave groove 31b is fitted. The coating of the coated optical fiber 5 is released by advancing obliquely along the ridge 30e and leaving outward from the center of the cross section. Thereby, the portion of the space where the open guide 31 that has moved outward from the center side of the cross section becomes a bending space, and the coated optical fiber 5 is bent in that space. That is, the butting pressure of the insertion fiber 6 against the built-in optical fiber 2 is converted into the deflection of the coated optical fiber 5. This deflection ensures an appropriate butt pressure for good optical connection.
(12) When the wedge member 15 is removed in this state, the clamping force of the C-shaped leaf spring acts, and the built-in optical fiber 2 and the inserted optical fiber 6 that is a bare fiber are formed by the base portion 30 and the lid portion 33 of the mechanical splice portion 7. And the coated optical fiber 5.
(13) Next, the lever 12 attached to the stop ring 10 is tilted so as to cover the outer cover holding member 11 holding the outer cover of the optical cable 4 and restrained so that the outer cover holding member 11 does not fall off.
This completes the assembly of the mechanical splice type field assembly optical connector.

1. Mechanical splice type on-site assembly optical connector (optical connector)
2 Built-in optical fiber (bare fiber)
3 Ferrule part 4 Optical cable 4a Outer jacket (outer jacket part)
5 Coated optical fiber 5a Coating (coating part)
6 Insertion optical fiber (bare fiber)
7 Mechanical splice part 8 Mechanical splice part integrated ferrule part 9 Plug frame 10 Stop ring 11 Cover member 12 Lever 13 Cover 20, 120, 120 'Cover removal member 21 Movable guide 30 Base part 33 Cover part 32a Alignment groove 32b Cover Part receiving groove 30a (deposit covering member) recess 31 open guide 40 voids 41, 141, 141 'bare fiber insertion holes 141a, 141a' (of bare fiber insertion holes) having the same inner diameter as the bare fiber diameter
141b, 141b ′ Tapered portions 141c, 141c ′ (on the inlet side of the bare fiber insertion hole) Tapered portions 42 (on the inlet side of the bare fiber insertion hole) Covered optical fiber insertion hole 43 Cover removal action portion (cone Body part)
44 Covered optical fiber insertion side portion 45 Cover removal side portion 51 Grip member main body 53 Lid

Claims (10)

A ferrule part containing a built-in optical fiber, and an insertion optical fiber attached to the rear part of the ferrule part, from which the coating of the coated optical fiber from which the sheath of the built-in optical fiber and the optical cable inserted from the outside is removed is removed A mechanical splice portion that butt-connects, and a coating removal portion that is provided on the rear side of the butt portion between the built-in optical fiber and the insertion optical fiber in the mechanical splice portion and removes the coating of the coated optical fiber,
The coating removal member constituting the coating removal unit is
A coated optical fiber insertion side portion having a coated optical fiber insertion hole for guiding the coated optical fiber;
The coated optical fiber is provided in front of the coated optical fiber insertion hole, has a bare fiber insertion hole coaxial with the coated optical fiber insertion hole, and removes the coating of the coated optical fiber at the end of the coated optical fiber insertion hole side. And a coating removal side portion having a coating removal working portion formed with a cylindrical blade for,
The inner diameter of the coated optical fiber insertion hole is substantially the same inner diameter as the outer diameter of the coated optical fiber, and the inner diameter of the intermediate portion of the bare fiber insertion hole is substantially the same as the outer diameter of the bare fiber. ,
A taper hole is formed such that the inlet side is tapered from the intermediate portion having the same inner diameter as the bare fiber outer diameter of the bare fiber insertion hole, and the inner diameter of the outlet side is larger than the inner diameter of the intermediate portion. A mechanical splice type on-site assembly optical connector.   2. The mechanical splice type site according to claim 1, wherein a portion of the bare fiber insertion hole in which an inner diameter on the outlet side is larger than an inner diameter of the intermediate portion is a tapered hole extending toward the outlet side. Assembly optical connector.   3. The mechanical splice according to claim 1, wherein a length of a portion having an inner diameter substantially the same as an outer diameter of the bare fiber in the bare fiber insertion hole in the coating removal side portion is 0.05 mm to 0.5 mm. Type field assembly optical connector.   The mechanical splice mold according to any one of claims 1 to 3, wherein the coating removing member is formed by integrally molding a coated optical fiber insertion side portion and a coating removal side portion with a molding material. On-site assembly optical connector.   5. The mechanical splice type on-site assembly optical connector according to claim 4, wherein the coating removal member is formed by integrally molding a coated optical fiber insertion side portion and a coating removal side portion with resin.   The said coating removal member was integrally molded by the metal mold | die using one core pin as a core which forms the part of a coated optical fiber penetration hole, and the part of a bare fiber penetration hole. 5. A field-assembled optical connector of the mechanical splice type according to 5.   The mechanical splice mold according to any one of claims 1 to 6, wherein a gap between the coated optical fiber insertion hole and the bare fiber insertion hole is 0.1 to 0.3 mm. On-site assembly optical connector.   The sheath removing action portion of the sheath removing member has a cone-shaped portion that is tapered toward the inlet side of the bare fiber insertion hole and the cylindrical blade is formed at the tip of the hole. The mechanically-spliced field assembly optical connector according to any one of claims 1 to 7, wherein a taper angle of a side surface is 20 ° to 40 °.   The sheath removing action portion of the sheath removing member has a concavely curved cone-like portion that is tapered toward the inlet side of the bare fiber insertion hole and is tapered to form the cylindrical blade at the tip of the hole. A mechanical splice type field assembly optical connector according to any one of claims 1 to 7. The space formed between the coated optical fiber insertion hole and the bare fiber insertion hole in the coating removal member is zero on both sides in the radial direction of the bare fiber insertion hole in two directions orthogonal to the bare fiber insertion hole core. A mechanical splice type field assembly optical connector according to any one of claims 1 to 9, wherein a gap of 5 mm or more is formed.

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