JPH023166B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical connector used for connection between optical fibers and between optical fibers and equipment;
In particular, it relates to an optical connector with a simplified structure.

In recent years, optical fibers have been widely used as a new communication or energy transmission medium not only for long-distance transmission but also for short-distance transmission within several kilometers. In such an optical communication system, an optical connector is an indispensable component in the system configuration, and is used to removably connect optical fibers when switching devices, removing transmitter/receiver units, etc.

Conventionally, optical connectors have been developed for long-distance transmission, and generally include a housing and a fiber holder for attaching an optical fiber to the housing. FIG. 1 shows an example of a fiber holder used in this conventional optical connector. The one shown in the same figure has a cylindrical shape with a bottom, and a hole is drilled with high precision in the center of the bottom for the nozzle 3.
It consists of a precision ferrule 2 with a

However, since this holder has a configuration in which the fiber wire 1a with the coating 1b removed is inserted into the nozzle 3 that has been precisely machined to match the fiber system, the ferrule becomes extremely expensive, and the thin nozzle 3
It is not easy to insert the fiber 1a into the fiber, and moreover, the fiber tip and cladding are likely to be damaged during insertion, resulting in a poor yield. Furthermore, since the optical fiber is fixed by filling the adhesive 4 into the ferrule 2, this method complicates the assembly process and requires time for assembly.

On the other hand, the housing includes a main body having a guide hole in the center for inserting and holding the fiber holder, and a cap nut for fixing the fiber holder inserted through the guide hole. Although this is common, the structure is complicated and large, and there is also the inconvenience of having to tighten and remove the cap nut each time the plug is attached or removed.

The present invention has been made in view of these drawbacks, and has a simple structure, which allows parts such as a fiber holder to be easily manufactured, prevents damage to the optical fiber when installing the optical fiber, and allows the plug to be easily installed. To provide an optical connector which can be assembled and furthermore allows a plug and an adapter to be attached and detached with one touch.

That is, the present invention is an optical connector of a type in which plugs are connected to each other via an adapter, and the plug has a fiber holder that holds an end of an optical fiber, and a fiber holder that is engaged and held. The fiber holder includes a housing that is removably fitted to the adapter, and a nozzle through which the distal end of the optical fiber from which the coating has been removed is inserted, and a tightening ring is fitted onto the outside to hold the fiber tightly; The adapter has a covering holding part that holds the covering by press-fitting a covering clamp provided in a cylindrical shape into the fitting hole and holding the covering, and the adapter has fitting parts with the housing at both ends. Additionally, a guide hole is provided in which the fiber holder nozzle is inserted and the end surfaces of the optical fibers to be connected face each other during plug fitting.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

FIG. 2 is a cross-sectional view showing one embodiment of the optical connector of the present invention, and FIG. 3 is a cross-sectional view taken along line A-A. In these figures, the optical connector of the present invention has plugs A and B attached to the ends of an optical fiber cable 1, respectively.
and an adapter C that interconnects them.

Plugs A and B include a fiber holder 10 attached to the tip of an optical fiber cable 1, and a fiber holder 10 attached to the tip of the optical fiber cable 1.
0 housing 30 and locking member 4
Consists of 0. In addition, in this embodiment, plugs A,
Since B has the same structure, only one will be explained below.

The fiber holder 10, as shown in FIG.
It is comprised of a ferrule 11, a tightening ring 18, and a covering clamp 20, and holds and fixes the optical fiber in the housing.

The ferrule body 11 is made of metal such as brass and has a cylindrical shape (in this embodiment, a cylinder), and has a nozzle 12 on the tip side that holds the optical fiber from which the coating has been removed, that is, a bare fiber wire, and a coating clamp 20 . A coating holding part 15 that holds the optical fiber coating by tightly press-fitting is provided on the proximal end side, and a locking part 1 is further provided on the proximal end.
6. The outer shape and size of this ferrule 11 are the same as those of the housing 30 and adapter C.
is set according to the structure of In this embodiment, the nozzle 12 side has a small diameter, and the coating holding part 15 side has a large diameter. This allows positioning within the housing 30 at the outer periphery of the covering holding portion 15, and
This is because the nozzle 12 is configured to be inserted into an adapter guide hole, which will be described later.

The nozzle 12 is configured by providing an axial through hole 13 on the tip side of the ferrule 11. Through hole 13
The diameter of the fiber strand 1a is as shown in FIG.
It is set to be slightly larger than the outer diameter of the fiber strand 1a to be attached so that it can be inserted freely. Further, on the outside of the tip of the nozzle 12, there is provided a tightening ring mounting portion 14 for enclosing a tightening ring 18, which will be described later. The wall thickness of this part is made slightly thinner than other parts, so that the tightening ring 18
It is easily deformed when externally fitted, and can be easily pressed against the outer periphery of the fiber strand 1a. However, this tightening ring attachment part 14 is not specially provided, and the nozzle 1
The tightening ring 18 may be attached to an arbitrary position (preferably at the tip) of 2.

The sheath holding part 15 is configured by providing a fitting hole 17 on the proximal end side of the ferrule 11 that communicates with the through hole 13, and its inner diameter is equal to the outer diameter of the sheath clamp 20 sheathed on the sheath 1b of the optical fiber cable 1. The clamp 20 is press-fitted tightly together with the optical fiber 1 to hold it.
In this embodiment, the covering holder 15 also has the function of supporting a ferrule within a housing 30, which will be described later.

A locking portion 16 is provided on the outer periphery of the base end of the ferrule 11. This locking portion 16 is formed in a flange shape, and engages with a locking portion of the housing 30 to lock the ferrule 11 to the housing, and also serves as a receiving portion for an elastic body to be described later. However, the shape of the locking portion 16 is not limited to the above-mentioned shape, and it may be in the shape of a protrusion or the like, and its position is not limited to the base end.

The tightening ring 18 is made of metal such as brass and has a through hole 1.
The ferrule 11 is formed into a cylindrical shape having a
It is attached to the tightening ring attachment part 14 of the. The cross-sectional shape of the through hole 19 is formed to match the outer shape of the tightening ring mounting portion 14, and is circular in this embodiment. Its inner diameter is set to be slightly smaller than the outer diameter of the tightening ring mounting portion 14 so that it can be mounted by press fitting. Further, the outer diameter is set so that the outer diameter when press-fitted into the tightening ring mounting portion 14 is approximately equal to or slightly smaller than the inner diameter of the guide hole of the adapter, which will be described later. In this embodiment, a taper 19a is provided at one end opening of the through hole 19 to facilitate press fitting.

This tightening ring 18 is attached to the ferrule 11 to tighten the nozzle 12 and tightly hold the fiber wire 1a inserted into the nozzle 12. Therefore, it is not limited to this embodiment as long as it performs the same function. For example, the ring is not limited to a closed ring, but may be a C-shaped cross section with a partially open ring. A plate-shaped material may be wrapped around the material. Furthermore, the attachment is not limited to press-fitting, but may also be a method of thermally expanding the tightening ring 18 and fitting it in, or a method of forming the tightening ring 18 from a shape memory alloy and attaching it using the shape memory effect. .

The sheathing clamp 20 is formed by punching or other means from a metal plate such as iron, and is tightly sheathed around the outer periphery of the sheath 1b of the optical fiber 1 in a cylindrical shape (cylindrical shape in this embodiment). Therefore, until it is covered with the covering 1b, it has a flat plate shape as shown in FIG. However, it may be formed in advance into a U-shape or a cylindrical shape.

A locking protrusion 21 is provided on the covering contact surface side of the covering clamp 20. This is to bite into the coating of the optical fiber cable to prevent the coating from coming off. This locking protrusion 21 is provided by cutting and raising, burring, or other means, and its shape is triangular in this embodiment in order to improve its penetration into the coating, but it is not limited to this. Any protrusion-like material is sufficient. Further, the protrusion height is made smaller than the thickness of the coating in order to prevent damage to the fiber strands. Note that this locking protrusion 21 is
If sufficient strength can be obtained to prevent the sheathing from coming off simply by crimping the sheathing clamp into a cylindrical shape, it is not necessary to provide it.

The locking convex portion 22 provided on the base end side of the covering clamp 20 is used to temporarily hold the elastic body 41 and washer 42 when assembling the optical connector, as shown in FIG. This is provided for convenience and may be omitted. Furthermore, the covering clamp 20 is longer than the depth of the fitting hole 17, and the proximal end protrudes outward when it is fitted into the fitting hole 17, but this is also for the same reason as mentioned above, so even if the length does not protrude, good.

The fiber holder 10 configured in this way is
As shown in FIG. 6, the optical fiber cable 1 is attached. This installation is done as follows. The optical fiber cable 1 consists of a fiber wire 1a consisting of a core and a cladding, and a coating 1b provided around the outer periphery of the fiber wire 1a. A slightly longer length is removed to expose the fiber strand 1a, and at the end of the coating 1b that is not removed,
The covering clamp 20 is tightly covered in a cylindrical shape. Next, the exposed fiber strand 1a is inserted into the through hole 13 of the nozzle 12, and the covered clamp 20 is press-fitted into the fitting hole 17 of the covering holding part 15. At this time, an elastic body 41 and a washer 42, which will be described later as a locking member, are fitted into the covering clamp 20 in advance. Then, the tightening ring 18 is press-fitted into the tightening ring attachment portion 14 of the nozzle 12.

In this way, the optical fiber is attached to the holder. In this case, the optical fiber strand 1a and the ferrule 11 are attached to the tip of the nozzle 12 by the tightening ring 18.
is pressed and deformed by the
Furthermore, even if stress is applied to the fiber strand 1a in the longitudinal direction, it will not come off or protrude, and the center of the fiber strand 1a can be aligned with the center of the nozzle 12. On the other hand, the sheathing 1b and the ferrule 11 are fixed by tightly fitting and holding the sheathing clamp 20 that is tightly fitted onto the sheathing 1b, so that even if stress is applied to the sheathing 1b in the longitudinal direction,
The coating 1b does not slip on the fiber strand 1a. Therefore, the optical fiber 1 is securely held by the fiber holder 10.

In this embodiment, a single optical fiber cable is used, but a bundle of a plurality of fiber wires may be used.

The housing 30 is made of synthetic resin, metal, etc., and has through holes 3 in the longitudinal direction as shown in FIG.
1, and is formed into a substantially cylindrical shape (cylindrical in this embodiment), and the fiber holder is engaged with the fiber holder using, for example, a locking member 40 shown in FIG. 9 to form a connector plug. .

The through hole 31 is a portion for fitting with an adapter C to be described later and for holding the fiber holder 10 described above, and its cross-sectional shape and diameter are set in accordance with the above function. Although the cross-sectional shape and diameter of the fitting portion and the holding portion are the same in this embodiment, they may not be the same. An undercut 3 is provided at the tip opening 32 of the through hole 31.
3 is provided, thereby ensuring a secure fit with the adapter.

Furthermore, a locking portion 34 for locking the fiber holder is provided on the proximal end side of the through hole 31. This locking portion 34 includes a first step portion 35 and a second step portion 36, which are provided with diameters increasing sequentially, and the second step portion 3.
A stop spring mounting hole 3 is provided on the outside of 6, perpendicular to the longitudinal direction.
7, and a locking member 40, which will be described later, is attached thereto.

The locking member 40 includes an elastic body 41, a washer 42, and a locking spring 43, and locks the fiber holder 10 to the housing 30. Elastic body 41
is formed in a ring or cylindrical shape from an elastic material such as rubber, and is for absorbing the displacement of the ferrule 11 within the housing 30. Therefore, the elastic body 41 may be a coil spring or the like. The set screw 43 is a spring formed in a substantially U-shape, and is inserted into the set spring mounting hole 37 of the housing 30 to lock the washer 42 . Note that the locking member 40 is not limited to the one described above, and may be configured using a snap ring instead of the set screw 43 and washer 42, for example.

The fiber holder is attached and locked to the housing 30 as follows. First, the fiber holder 10 with the optical fiber cable 1 attached is
It is inserted into the through hole 31 from the base end side of the housing 30, and the ferrule locking part 16 is inserted into the housing locking part 3.
4. The first step portion 35 of No.4 is brought into contact with the first step portion 35 of No.4. Next, the stop spring 43 is inserted into the stop spring mounting hole 37 to lock the washer 42 that has been fitted into the covering clamp 20 in advance. As a result, the fiber holder 10
Movement toward the distal end is prevented by the first step portion 35,
Movement toward the proximal end is prevented by an elastic body 41, a washer 42, and a stop spring 43.

Next, the adapter C is made of metal, plastic, etc., and has a generally cylindrical shape as a whole, as shown in FIG. 9, and is interposed between the plugs to connect them facing each other. Fitting parts 51, 51 each having an engaging convex part 53 at the base that engages with the undercut 33 of the housing 30 are protruded from both ends of the adapter C. Holder 1
A guide hole 52 into which the nozzle 12 of No. 0 is inserted is provided.

The guide hole 52 is provided with a cross-sectional shape and diameter that allows the nozzle to be inserted and removed freely. or,
The length is set so that when the plugs A and B are fitted into the adapter C, the ends of the optical fiber cables held by both plugs face each other and abut.
The play between the inner diameter of the guide hole 52 and the outer diameter of the nozzle 12 fitted with the tightening ring 18 is determined by
2 can be kept to a small value so as not to make it difficult to insert the fibers 1a, 1a, thereby making it possible to make the axis misalignment of the opposing nozzles 12, 12, and even the axis misalignment between the fiber wires 1a, 1a extremely small.

Note that the adapter C may have a configuration in which a focusing light transmitting body such as a self-occurring lens or a ball lens is attached to the center of the guide hole 52, and the fiber wires are opposed to each other through this intervening body.

The adapter C and the plugs A and B are fitted by inserting the nozzle 12 of each plug into the guide hole 52 and the fitting part 51 into the housing through hole 31, and then inserting the engagement protrusion into the undercut 33. Part 53
This is done by engaging the Due to this fitting, the fiber wires 1 of both plugs A and B are inserted into the guide hole 52.
a and 1a are coaxially supported by the nozzle 12 of the fiber holder 10 and are brought into contact with each other with minimal axis deviation. In this case, the fiber holder 10 can be slightly displaced in the axial direction due to the elasticity of the elastic body 41, and a pressing force is applied, so that the end surfaces of the opposing fiber wires 1a, 1a can be brought into secure contact with each other. can.

In the above embodiment, the case where the plug is used to connect optical fiber cables to each other is shown, but by incorporating one of the plugs and the adapter C into the device, it can also be used to connect the optical fiber to the device. For example, it can be assembled into a device by attaching a bracket to the adapter C and attaching the bracket to a hole in the wall of the device. In this case, the plug inside the device is
The housing may be omitted and the fiber holder may be directly fixed to the adapter. Furthermore, a light emitting element and a light receiving element may be installed inside the device of the adapter instead of the optical fiber.

Furthermore, in the above embodiment, a single pin connector is shown, but the adapter may be provided with multiple sets of fitting parts, and correspondingly, multiple sets of plugs may be arranged in a single housing. It may be formed into a multi-pin connector.

Furthermore, in this embodiment, the undercut and the engagement protrusion are used as the means for engaging the plug and the adapter, but the invention is not limited thereto. good.

As explained above, the present invention covers the inserted fiber wire with a tightening ring to tightly hold it on the tip side, and also holds the coating by press-fitting a coating clamp having a cylindrical coating on the optical fiber. A housing is provided with a fitting portion between the fiber holder and the adapter configured to engage and hold the fiber holder, and a fitting portion between the housing and the fiber holder is provided. By comprising an adapter with a guide hole into which the tip of the holder can be freely inserted and removed, the fiber holder, which conventionally required precision processing, can be produced with a simple structure and at low cost. This has the advantage that the optical fiber can be easily attached without damaging the optical fiber and without using an adhesive, and the optical connector can be manufactured easily and with a high yield. Furthermore, since the tip of the optical fiber wire is concentrically supported by the ferrule and the guide hole of the adapter, it is possible to connect the connector with high accuracy despite the simple structure. Furthermore, by pushing and pulling the plug and adapter in the axial direction, they can be attached and detached with a single touch, which is convenient in practice.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a fiber holder used in a conventional optical connector, FIG. 2 is a sectional view showing an embodiment of the optical connector of the present invention, and FIG.
-A sectional view, FIG. 4 is an exploded sectional view showing an example of the fiber holder used in the above embodiment, FIG. 5 is a plan view showing an example of the covering clamp constituting the fiber holder, and FIG. 6 7 is a cross-sectional view showing an example of the connector housing used in the above embodiment, and FIG. 8 is a cross-sectional view showing the optical fiber cable attached to the fiber holder. FIG. 9 is a perspective view showing an example of a locking member, and FIG. 9 is a partially cutaway front view showing an adapter used in the above embodiment. A, B...Plug, C...Adapter, 1...Optical fiber cable, 1a...Fiber wire, 1b
... Coating, 10 ... Fiber holder, 11 ... Ferrule, 12 ... Nozzle, 13 ... Through hole, 1
4... Tightening ring attachment part, 15... Covering holding part,
16...Locking part, 17...Tightening ring, 20...
Covering clamp, 30... Housing, 31... Through hole, 33... Undercut, 34... Locking portion, 40... Locking member, 41... Elastic body, 51...
...Fitting portion, 52...Guide hole, 53...Engagement convex portion.

Claims (1)

[Claims] 1. An optical connector of a type in which plugs are connected to each other via an adapter, wherein the plug has a fiber holder that holds an end of an optical fiber, and a fiber holder that engages and holds the fiber holder. The fiber holder includes a nozzle into which the tip of the optical fiber from which the coating has been removed is inserted, and a tightening ring is fitted onto the outside to hold the fiber tightly. and a covering holding part that holds the covering by tightly press-fitting a cylindrical covering clamp into the covering part, and the adapter has fitting parts with the housing at both ends, and . An optical connector comprising a guide hole into which the fiber holder nozzle is inserted and the end surfaces of the optical fibers to be connected face each other during plug fitting.