JP2593042Y2 - Outer member of ferrule for optical connector - 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 used for connecting optical fibers to each other, and more particularly to an outer member forming an outer portion of the ferrule.

[0002]

2. Description of the Related Art In a connector for connecting an optical fiber used as a data transmission medium, an end of an optical fiber to be connected is inserted into and attached to a ferrule. The contact is made. By the way, such a ferrule is proposed in Japanese Patent Application Laid-Open No. 3-167506. In this case, the ferrule is composed of an outer ferrule having a longitudinal through hole, and an inner ferrule holding an optical fiber and press-fitting into the through hole. And the outer ferrule
It is composed of a resin outer member having a press-fit hole formed therein, and a metal tube member press-fitted into the press-fit hole and receiving the press-fit of the inner ferrule. Thereby, the press input of the inner ferrule is received by the tube member, and the deformation and breakage of the outer member are prevented.

By the way, when the outer member is formed, in order to make the mold easily come out of the press-fitting hole, the mold is provided with a base end in the press-fitting direction from a part for forming the front end in the press-fitting direction. A taper is provided so that the outer diameter increases toward the portion to be molded. For this reason, the press-fitting hole formed by the mold is tapered so that the inner diameter increases from the distal end to the base end in the press-fitting direction.

[0004] If the press-fitting hole has such a taper, when the tube member is press-fitted into the press-fitting hole,
Play may occur between the base end of the press-in hole and the tube member, and the tube member may easily fall out of the press-in hole. For this reason, in order to minimize such backlash, the inner diameter at the distal end of the press-fitting hole is made considerably smaller than the outer diameter of the tube member, and the inner diameter at the base end of the press-fitting hole is made as small as possible to the outer diameter of the tube member. There is a method of approaching.

[0005]

However, in such a method, it is difficult to press-fit the tube member at the tip of the press-fitting hole, and the tip portion of the outer member is deformed so as to expand radially outward of the tube member. There is a problem. And if there is such a deformation, it will be difficult to connect with the ferrule of the other party.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and has a ferrule for an optical connector in which it is possible to prevent rattling between a press-fit hole of an outer member and a tube member press-fitted therein. The purpose of the present invention is to provide an outer member.

[0007]

In order to achieve the above object, in the outer member of the present invention, the outer periphery of the tube member press-fitted into the press-fitting hole is provided near the base end of the wall portion forming the press-fitting hole. A ring-shaped projection that contacts the surface is formed.

[0008]

According to such an outer member, even if the front end of the press-fitting hole in the press-fitting direction is formed in accordance with the outer shape of the tube member (that is, neither small nor large), the tube member press-fitted into the press-fitting hole does not The outer periphery of the base end is held by the ring-shaped projection. Therefore, the outer ferrule can be assembled without deforming the distal end portion of the outer member as described above and without causing backlash between the tube member and the press-fitting hole.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a ferrule 1 for an optical connector using an outer member according to the present invention. This ferrule 1 is composed of an outer ferrule 2 formed in a stepped cylindrical shape whose outer shape becomes smaller in diameter toward the tip, and an inner ferrule 3 which holds the optical fiber 5 and is press-fitted into the outer ferrule 2. ing.

As shown in FIG. 2, the outer ferrule 2 includes a resin outer member 21 and a metal tube 22.
It is composed of A press-fit hole 21 extending in the longitudinal direction from near the front end to near the rear end of the outer member 21.
a is formed. A guide hole 21b extending in the longitudinal direction and having a funnel-shaped portion that opens to the side of the press-in hole 21a is formed ahead of the press-in hole 21a. The distal end of the guide hole 21b is open at the distal end surface of the outer member 21. Further, behind the press-in hole 21a, the press-in hole 2 is provided.
A positioning hole 21c having a diameter larger than 1a and opening at the rear end face is formed. And the press-fit hole 21
The metal tube 22 is press-fitted in a.

The inner ferrule 3 is formed of a resin. As shown in FIG. 1, the inner ferrule 3 has a substantially cylindrical long shape, and has a small-diameter press-fit portion 3a extending from the front end to the vicinity of the rear end, and a large-diameter positioning portion provided near the rear end. It comprises a portion 3b and a small-diameter end portion 3c extending from the portion 3b to the rear end. Press-fit part 3
As for a, a tapered portion 3e which is tapered is formed at its tip. The inner ferrule 3 is divided into two holding pieces 31 and 32 along the longitudinal axis, and the divided portions include receiving grooves 31a and 32 extending in the longitudinal direction.
a is formed.

The optical fibers 5 are received and held in the receiving grooves 31a and 32a. The optical fiber 5 has a fiber strand 5a for transmitting an optical signal at the center, and the periphery of the strand 5a is covered to form a core wire 5b. The optical fiber 5 is held by the holding pieces 31, 3 serving as the inner ferrule 3 in a state where the fiber element wire 5 a is exposed at the distal end.
2 Then, the inner ferrule 3 holding the optical fiber 5 is connected to the outer member 2 as shown in FIG.
The fiber strand 5a that is pressed into the inside of the tube 22 while inserting the fiber strand 5a into the one guide hole 21b, and protrudes from the tip end face of the outer member 21, is cut at the tip end face of the outer member 21. Thus, the ferrule 1 is assembled.

Incidentally, a mold (not shown) used for forming the press-fitting hole 21a in the step of forming the outer member 21 is provided with a base in the longitudinal direction from the front end in the longitudinal direction so as to be easily removed from the press-fitting hole 21a after the forming. It is slightly tapered so that the outer diameter increases toward the end. For this reason, the press-fit hole 21a formed by this mold also has a taper T so that the inner diameter increases from the distal end to the base end in the press-fit direction (longitudinal direction). Therefore, there is a possibility that play may occur between the base end of the tube 22 and the press-fitting hole 21a even though the tube 22 is press-fitted into the press-fitting hole 21a as described above.

For this reason, in the outer member 21, the vicinity of the base end of the wall surface forming the press-fit hole 21a is shown in FIG.
As shown in an enlarged manner in FIG. The inner diameter of the ring-shaped projection 21d is substantially equal to the outer diameter of the tube 22.

Accordingly, the outer peripheral surface of the base end of the tube 22 press-fitted into the press-fitting hole 21a abuts on the ring-shaped projection 21d and is held without play. Thereby, it is possible to prevent the tube 22 from easily falling out of the outer member 21.

In this embodiment, the ring-shaped protrusion 21d
Is formed so as to be continuous without a break in the middle in the circumferential direction, but has a break in the middle and is connected intermittently (for example, a protrusion held at three points every 120 degrees or a four point every 90 degrees) ) Can be used.

[0017]

As described above, when the outer member of the present invention is used, the base end portion of the tube pressed into the tapered press-fitting hole is inserted between the press-fitting hole and the ring-shaped projection. It is held without play. Therefore, the press-fitted tube can be reliably prevented from coming off the outer member, and the reliability of the optical connector ferrule can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a ferrule for an optical connector using an outer member according to the present invention.

FIG. 2 is a side sectional view of the ferrule.

FIG. 3 is a partially enlarged sectional view of an outer member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrule for optical connectors 2 Outer ferrule 21 Outer member 21a Press-fit hole 21d Ring-shaped protrusion 22 Tube 3 Inner ferrule 5 Optical fiber

Claims (1)

(57) [Scope of request for utility model registration] 1. An optical connector having a press-fitting hole into which a tube member for holding an optical fiber is press-fitted, and wherein the press-fitting hole is tapered so that the inner diameter increases from the distal end to the base end in the press-fitting direction. An outer member of the ferrule for use, wherein a ring-shaped projection is formed in the vicinity of the base end portion in the wall portion of the press-fitting hole, which is in contact with the outer peripheral surface of the tube member press-fitted into the press-fitting hole. An outer member of a ferrule for an optical connector.