JP7123632B2 - optical connector - Google Patents

Description

The present invention relates to an optical connector that has a simple structure and is easy to assemble.

Conventionally, when connecting an optical connector to the tip of an optical cord, an optical fiber of the optical cord is connected to an optical fiber built in a ferrule, and a member such as a housing is assembled so as to accommodate this connecting portion. was

As for the structure of such an optical connector, the optical fiber core wire contained in the ferrule and the optical fiber core wire pulled out from the optical cord are fusion-spliced, and the outer covering of the optical cord is removed at the rear of the housing. A method has been proposed in which the outer cover of the optical cord is fixed by pressing it with a pressed member and further by screwing the fixing member and the housing together (for example, Patent Document 1).

JP 2011-118348 A

However, if an attempt is made to fix the jacket of the optical cord by screwing the fixing member as in Patent Document 1, there is a risk that the jacket will rotate together with the fixing member when the fixing member is screwed. In such a case, twisting occurs in the optical fiber inside the optical cord, causing damage to the optical fiber, transmission loss, and the like.

In addition, two parts, the jacket pressing member and the fixing member, are required to fix the jacket of the optical cord to the rear end of the housing, resulting in a large number of parts and a complicated structure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical connector which has a small number of parts and is easy to assemble.

In order to achieve the above object, the present invention provides an optical connector in which a built-in optical fiber held by a ferrule and an optical fiber inside an optical cord are connected, comprising: a housing connected to the ferrule; and a fixing member that is screwed and connected to the rear of the housing, wherein the jacket at the tip of the optical cord is split along the longitudinal direction, and the split tip of the jacket is attached to the rear end portion of the housing. is arranged on the outer periphery of the housing, the tip of the outer cover is sandwiched and fixed between the housing and the fixing member, and a protrusion projecting radially is formed in the circumferential cross section of the rear end of the housing, The outer covering is arranged at a portion other than the protrusion, the tensile strength fibers inside the optical cord are arranged in a tensile strength fiber holding portion different from the outer covering holding portion in which the outer covering is arranged, and the outer covering The holding portion is repeatedly uneven in the axial direction of the housing, and the connection portion between the built-in optical fiber held by the ferrule and the optical fiber inside the optical cord is reinforced by a protective sleeve, and is separated from the fixing member. A tube covers the outer periphery of the exposed optical code for a predetermined length, the tube has at least a two-layer structure, and has an inner resin layer and an outer resin layer provided on the outer periphery of the inner resin layer, The inner resin layer is made of a resin having a relatively high hardness, the outer resin layer is made of a resin having a relatively low hardness, the tube is inserted through a hole provided at the rear end of the fixing member, A large-diameter portion is formed at a distal end portion of the tube on the side of the fixing member, and the large-diameter portion is fitted into a reduced-diameter portion at the rear end portion of the fixing member to connect the tube and the fixing member. The optical connector is characterized in that the reduced-diameter portion and the large-diameter portion come into contact with each other to prevent the tube from slipping out of the fixing member .

According to the present invention, the outer cover of the optical cord can be fixed without using the outer cover pressing member, so the number of parts can be reduced. In addition, since the rear end portion of the housing is provided with a radially protruding protrusion, and the outer cover is arranged at a portion other than the protrusion, even if the outer cover tries to rotate, the protrusion restricts the rotation. Therefore, the rotation of the outer cover can be suppressed when the fixing member is screwed. Therefore, assembly work is easy.

In addition, when the optical code exposed from the fixing member is covered with the tube, the inner layer of the tube is made of resin with relatively high hardness, and the outer layer is made of resin with relatively low hardness, the operation of inserting the optical code through the tube. is easy, and the flexibility when bent can be increased. Further, by forming the large-diameter portion at the tip of the tube, the tube can be easily connected to the fixing member by the large-diameter portion.

According to the present invention, it is possible to provide an optical connector with a small number of parts and good assembling workability.

2 is a perspective view of the optical connector 1; FIG. (a) is a plan view of the optical connector 1, and (b) is a side view of the optical connector 1. FIG. (a) is a cross-sectional view taken along line AA of FIG. 2(a), and (b) is a cross-sectional view taken along line BB of FIG. 2(b). 3 is an exploded perspective view of a second housing 13, a fixing member 19, and a tube 21; FIG. (a) is a CC arrow view of FIG. 4, and (b) is a view showing a state in which the jacket is arranged in (a). Sectional drawing of the tube 21. FIG.

An optical connector 1 according to an embodiment of the present invention will be described below. 1 is a perspective view of the optical connector 1, FIG. 2(a) is a plan view of the optical connector 1, and FIG. 2(b) is a side view of the optical connector 1. FIG. 3(a) is a cross-sectional view taken along the line AA of FIG. 2(a), and FIG. 3(b) is a cross-sectional view taken along the line BB of FIG. 2(b).

As shown in FIGS. 3(a) and 3(b), the optical connector 1 is a so-called SC connector, and mainly includes a ferrule 3, a first housing 5, a spring 9, a protective sleeve 11 and a second housing 13. , a fixing member 19, a tube 21, and the like. An LC connector may be used as an optical connector to which the present invention can be applied.

The optical connector 1 is formed at the tip of the optical cord 27 . The optical cord 27 contains an optical fiber 29 inside, and a tensile strength fiber 33 is formed around the outer circumference of the optical fiber 29, and a jacket 31 is further formed around the outer circumference.

A built-in optical fiber 25 is held inside the ferrule 3 . The built-in optical fiber 25 is connected to the optical fiber 29 of the optical cord 27 . That is, inside the optical connector 1 , the built-in optical fiber 25 held by the ferrule 3 and the optical fiber 29 inside the optical cord 27 are connected, and the connection is reinforced by the protective sleeve 11 .

A ferrule 3 is housed in the first housing 5 . The ferrule 3 is composed of a ferrule body and a flange portion, and the ferrule body holds the built-in optical fiber 25 described above. A flange portion is connected and fixed to the rear end portion of the ferrule body.

A spring 9 is arranged behind the ferrule 3 (flange portion). Ferrule 3 is pressed against first housing 5 by spring 9 . Pushing the ferrule 3 backwards against the spring 9 allows the ferrule 3 to slide backwards with respect to the first housing 5 .

The first housing 5 is housed in the knob 15 . The knob 15 is a part for attaching and detaching to and from the adapter to be connected.

A second housing 13 is joined to the rear of the first housing 5 . A connecting portion between the built-in optical fiber 25 of the ferrule 3 and the optical fiber 29 of the optical cord 27 is arranged inside the second housing 13 . That is, the ferrule 3 is connected with the second housing 13 through the first housing 5 . In addition, in the present invention, the first housing 5 and the second housing 13 may be collectively referred to simply as a housing. Details of the second housing 13 will be described later.

A fixing member 19 is arranged behind the second housing 13 . A male threaded portion is formed on the outer peripheral portion of the second housing 13 and is screwed with a female threaded portion formed on the inner surface of the fixing member 19 . That is, the fixing member 19 can be fixed to the second housing 13 by screwing the fixing member 19 to the rear of the second housing 13 .

A tube 21 is joined to the rear of the fixing member 19 . The tube 21 is made of flexible resin, is a member that suppresses sudden bending of the optical cord 27 , and is arranged around the outer circumference of the optical cord 27 . Details of the tube 21 will be described later.

Next, the structure for retaining the optical cord will be described in detail. 4 is an exploded perspective view of the second housing 13, the fixing member 19 and the tube 21. FIG.

As described above, the external threaded portion is formed on the outer peripheral surface of the second housing 13 . The male threaded portion is screwed with a female threaded portion formed on the inner surface of the fixing member 19 . At this time, a gap is formed between the male threaded portion formed on the outer periphery of the second housing 13 and the female threaded portion formed on the inner surface of the fixing member 19, and the tensile strength fiber 33 of the optical cord 27 is sandwiched. That is, the male threaded portion formed on the outer peripheral surface of the second housing 13 serves as the tensile strength fiber holding portion 37 .

A jacket holding portion 39 having a smaller diameter than the tensile strength fiber holding portion 37 is provided behind the tensile strength fiber holding portion 37 of the second housing 13 . The jacket holding portion 39 is a portion where the jacket 31 of the optical cord 27 is held. The jacket holding portion 39 has an uneven shape that continues for a predetermined length in the circumferential direction. That is, the outer cover holding portion 39 is repeatedly uneven in the axial direction (longitudinal direction) of the second housing 13 .

FIG. 5(a) is a view taken along line CC of FIG. A pair of outer cover holding portions 39 are formed at positions facing each other in a substantially half circumference, respectively. be done. That is, in the circumferential cross section of the rear end portion of the second housing 13 , a projection 41 projecting in the radial direction is formed, and the outer cover holding portion 39 is sandwiched between the projections 41 in the circumferential direction. In the illustrated example, the protrusions 41 are arranged at two opposing locations, but may be arranged at one location or at three or more locations.

As described above, the jacket 31 is arranged on the jacket holder 39 . FIG. 5B is a conceptual diagram showing a state in which the outer cover 31 is arranged on the outer cover holding portion 39. As shown in FIG. A jacket 31 at the tip of the optical cord 27 is torn and split along the longitudinal direction. The tip of the divided outer cover 31 is placed in a cover holding portion 39 formed on the outer circumference of the rear end portion of the second housing 13 . In other words, the jacket 31 is arranged at a site other than the protrusion 41 .

As shown in FIG. 3B, by screwing the fixing member 19 into the second housing 13 in this state, the tip of the jacket 31 is sandwiched and fixed between the second housing 13 and the fixing member 19. . At this time, the outer cover 31 is pressed against the outer cover holding portion 39 , and even if the outer cover 31 tries to rotate around the outer circumference of the second housing 13 when the fixing member 19 is screwed in, the protrusion 41 prevents the outer cover 31 from rotating. rotation is regulated. Therefore, twisting of the optical fiber 29 inside the optical cord 27 can be suppressed.

Next, a method for assembling the optical connector will be described. First, with the protective sleeve 11 retracted to the optical cord 27, the optical fiber 29 of the optical cord 27 and the built-in optical fiber 25 of the ferrule 3 are set in a fusion splicer and fusion spliced. At this time, a transfer cap is connected to the tip of the ferrule 3 as required.

At the end of the optical cord 27, the jacket 31 is peeled off in advance by a predetermined length, and the internal tensile strength fiber 33 and the optical fiber 29 are pulled out. At this time, the distal end portion of the jacket 31 is torn by a predetermined length, for example, into two parts in the circumferential direction.

After the optical fiber 29 and the built-in optical fiber 25 are fused, the protective sleeve 11 is moved to the connecting portion and fixed. The protective sleeve 11 has, for example, a heat-shrinkable member and a core material, and by heating the connecting portion between the optical fiber 29 and the built-in optical fiber 25, the protective sleeve 11 can be fixed to the connecting portion.

Next, the spring 9 and the second housing 13 that have been retracted to the optical cord 27 are moved to join the rear end of the first housing 5 and the second housing 13 together. The first housing 5 and the second housing 13 can be joined by, for example, a latch (not shown) or the like.

In the state where the second housing 13 is connected to the first housing 5, the jacket 31 that is torn and split at the end of the optical cord 27 is spread at the rear end of the second housing 13 and It is arranged in the jacket holding portion 39 . Also, the tensile strength fibers 33 led out from the optical cord 27 are arranged in the tensile strength fiber retention section 37 through the jacket retention section 39 .

Next, the fixing member 19 and the tube 21 that have been retracted to the optical cord 27 are moved, and the male screw portion (tensile fiber holding portion 37) on the outer peripheral portion of the second housing 13 and the inner surface of the fixing member 19 are formed. The second housing 13 and the fixing member 19 are joined by screwing together the female threaded portion. That is, the fixing member 19 can be fixed to the second housing 13 by screwing the fixing member 19 into the second housing 13 .

At this time, as shown in FIG. 5( b ), the height of the protrusion 41 with respect to the jacket holding portion 39 is lower than the thickness of the jacket 31 . Therefore, when the fixing member 19 is screwed into the second housing 13 , the inner surface of the fixing member 19 presses the jacket 31 toward the second housing 13 from the outside. That is, the outer cover 31 is strongly sandwiched between the fixing member 19 and the second housing 13, so that the outer cover 31 can be fixed.

Also, the tensile strength fibers 33 arranged along the outer circumference of the second housing 13 are sandwiched between the male threaded portion and the female threaded portion between the second housing 13 and the fixing member 19 . That is, a slight gap is formed between the male threaded portion and the female threaded portion between the second housing 13 and the fixing member 19, and the tensile strength fibers 33 are sandwiched in this gap. For this reason, the tensile strength fibers 33 can be retained and fixed to the outer circumference of the second housing 13 . The optical connector 1 can be assembled by the above.

A tube 21 is attached in advance to the rear end portion of the fixing member 19 . FIG. 6 is an enlarged view of part D in FIG. The tube 21 covers the outer circumference of a predetermined length of the optical cord 27 exposed from the rear of the fixing member 19 .

As described above, when the optical fiber of the optical cord 27 is fused with the built-in optical fiber 25 of the ferrule 3, the jacket 31 of a predetermined length at the tip of the optical cord 27 is torn off to release the light inside. A predetermined length of fiber 29 must be exposed. The tube 21 covers the optical cord 27 at least in the area where the outer covering 31 of the optical cord 27 is torn.

Here, the tube 21 has at least a two-layer structure, and has an internal resin layer 21a and an external resin layer 21b provided on the outer periphery of the internal resin layer 21a. The inner resin layer 21a is made of a relatively hard resin, such as polytetrafluoroethylene (PTFE) resin, and the outer resin layer 21b is made of a relatively low-hardness resin, such as ethylene- A vinyl acetate copolymer (EVA) resin or the like is applicable.

An intermediate resin layer 21c is provided between the inner resin layer 21a and the outer resin layer 21b at a portion of the tip of the tube 21 on the fixing member side. That is, the portion where the intermediate resin layer 21c is provided becomes a large-diameter portion having a larger diameter than other portions. The rear end of the fixing member 19 is provided with a hole through which the tube 21 is inserted. .

When attaching the tube 21 to the optical cord 27 , the fixing member 19 is fitted to the optical cord 27 in advance, and then the optical cord 27 is inserted through the tube 21 . At this time, if the outer cover 31 of the optical cord 27 and the inner surface of the tube 21 do not slide well, it is difficult to attach the tube 21 .

On the other hand, if the tube 21 is made of a resin having a certain degree of rigidity, which allows good sliding with the optical cord 27, the bendability of the optical cord 27 is deteriorated. For this reason, the tube 21 should be made of a resin that has relatively high hardness, rigidity, and good slippage to ensure attachment to the optical cord 27, and the outer layer should be made of a resin that has a low hardness and is easy to bend. Bendability can be ensured. When the fixing member 19 is moved to the distal end side of the optical cord 27, as described above, the reduced diameter portion of the rear end portion of the fixing member 19 and the large diameter portion of the tube 21 come into contact with each other, so that the tube 21 is separated from the fixing member 19. can be prevented from coming off.

In addition, the outer resin layer 21b can be made of a heat-shrinkable resin. As a process for manufacturing the tube 21, the inner resin layer 21a, the intermediate resin layer 21c, and the outer resin layer 21b are passed through a metal rod or the like having approximately the same diameter as the optical cord, and then adjusted to predetermined positions. , 21a, 21c, and 21b can be integrated by heat shrinking the outer resin layer 21b. After the integration, the tube 21 is manufactured by pulling out a metal rod or the like.
Here, by making the length of the outer resin layer 21b longer than the length of the inner resin layer 21a, the inner resin layer 21a does not protrude behind the outer resin layer 21b at the rear of the tube 21 .

According to the present embodiment, when the fixing member 19 is screwed into the second housing 13, the protrusion 41 is formed between the outer cover holding portions 39 on which the outer cover 31 is arranged. , the outer cover 31 can be prevented from rotating together with the fixed member 19 .

Further, the outer cover 31 is compressed between the outer cover holding portion 39 of the second housing 13 and the inner surface of the fixing member 19 and is pressed against the uneven shape of the outer cover holding portion 39 to be fixed. For this reason, other members such as a jacket pressing member for fixing the jacket 31 are not required, and the number of parts can be reduced.

In addition, even when it is necessary to lengthen the length of the torn outer cover 31 at the tip of the optical cord 27 for setting to the fusion splicer, the torn outer cover 31 can be covered by using the tube 21 . can.

In addition, since the tube 21 has a two-layer structure and the inner resin layer 21a is made of a relatively hard resin, the operation of attaching the tube 21 to the optical cord 27 is facilitated. In addition, since the outer resin layer 21b is made of a relatively soft resin, the bendability of the optical cord 27 can be improved.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not influenced by the above-described embodiments. It is obvious that a person skilled in the art can conceive various modifications or modifications within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. be understood to belong to

For example, the shape of each part constituting the optical connector 1 is not limited to the illustrated example.

Reference Signs List 1 Optical connector 3 Ferrule 5 First housing 9 Spring 11 Protection sleeve 13 Second housing 15 Knob 19 Fixing member 21 Tube 21a Internal resin layer 21b External resin layer 21c Intermediate resin layer 25 Built-in optical fiber 27 Optical cord 29 Optical fiber 31 Jacket 33 …… Tensile fiber 37 …… Tensile fiber holding portion 39 …… Jacket holding portion 41 …… Protrusion

Claims (4)

An optical connector in which a built-in optical fiber held by a ferrule and an optical fiber inside an optical cord are connected,
a housing connected to the ferrule;
a fixing member threadedly connected to the rear of the housing;
and
The jacket at the tip of the optical cord is split along the longitudinal direction, the split tips of the jacket are arranged on the outer periphery of the rear end of the housing, and the tips of the jacket are connected to the housing and the housing. It is sandwiched and fixed with a fixing member,
A protrusion projecting in the radial direction is formed in a circumferential cross section of the rear end of the housing, and the outer cover is disposed at a portion other than the protrusion,
The tensile strength fibers inside the optical cord are arranged in a tensile strength fiber holding portion different from the jacket holding portion where the jacket is arranged,
The outer cover holding portion is repeatedly uneven in the axial direction of the housing,
The connecting portion between the built-in optical fiber held by the ferrule and the optical fiber inside the optical cord is reinforced with a protective sleeve ,
a tube covering a predetermined length of the outer circumference of the optical cord exposed from the fixing member;
The tube has at least a two-layer structure, and has an inner resin layer and an outer resin layer provided on the outer periphery of the inner resin layer, the inner resin layer being made of a resin having a relatively high hardness, and the outer resin layer having a relatively high hardness. The resin layer is made of resin with relatively low hardness,
The tube is inserted through a hole provided at the rear end of the fixing member, and a large-diameter portion is formed at the tip of the tube on the fixing member side, and the large-diameter portion extends from the rear end of the fixing member. to connect the tube and the fixed member, and the reduced diameter portion and the large diameter portion come into contact with each other to prevent the tube from coming off from the fixed member. An optical connector characterized by: An intermediate resin layer is provided between the internal resin layer and the external resin layer at a part of the distal end portion on the fixing member side, and the large-diameter portion is formed by the intermediate resin layer. 2. The optical connector according to claim 1 . 2. The length of said outer resin layer is longer than the length of said inner resin layer, and said inner resin layer does not protrude rearward beyond said outer resin layer at the rear of said tube. Or the optical connector according to claim 2 . 4. The optical connector according to any one of claims 1 to 3 , wherein the jacket holding portion has a smaller diameter than the tensile strength fiber holding portion.

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