JP3378216B2 - Optical fiber connecting sleeve and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sleeve for connecting end portions of optical fibers and a method for manufacturing the sleeve.

[0002]

2. Description of the Related Art Generally, when connecting optical fibers to each other in an optical communication means using optical fibers, the end portions of the optical fibers are covered with a cylindrical body called a ferrule, and the ferrule is covered with a cylindrical sleeve. The ends of the optical fibers are connected by inserting them from both sides and attaching the front faces of the ferrules from both sides.

FIG. 4 shows the shape of a general sleeve 1, which is constructed as a cylindrical body in which a linear slit 2 is formed in the length direction. Since the slits 2 are provided, elasticity is imparted in the circumferential direction, and when the ferrule 4 attached to the end of the optical fiber 3 is attached to the sleeve 1, the ferrule 4 is elastically held.

[0004]

By the way, as the material of the sleeve 1, zirconia ceramics and phosphor bronze are often used. Zirconia ceramics has a stable property against rust and discoloration, and has a feature that dust is hardly attached, but it has a problem that the price is high. On the other hand, although phosphor bronze has an appropriate elasticity and is cheaper than zirconia ceramics, it has problems such as discoloration of the surface and corrosion during long-term use.
Also, if the surface of the sleeve 1 is rough, the outer surface of the ferrule 4 may become black due to the metal powder of phosphor bronze, or dust may adhere to the outer surface of the ferrule 4 while the ferrule 4 is detached and attached several times. There was a risk of causing light loss.

Therefore, an object of the present invention is to form a protective coating on the inner peripheral surface of a cylindrical metal sleeve, thereby avoiding the problems associated with the use of the metal sleeve such as phosphor bronze, and to make zirconia. It is an object to provide a metal sleeve having properties comparable to those of ceramics at low cost. By the way, the conventional method of manufacturing a metal sleeve is either a race process in which a slit is made after drilling a round bar using an automatic lathe, or slitting is done, or a pipe that has been preprocessed to the diameter of the sleeve has a predetermined length. Since the pipe was cut and slits were formed in it, uniform plating or the like could not be formed on the surface of the sleeve that was processed into a cylindrical shape.

[0006]

In order to solve the above-mentioned problems, the present inventor found that, in the process of forming a metal sleeve by press working, the sleeves are staggered in the circumferential direction in the process.
By forming three strong tongue pieces and a strong protective coating on the surface (inner peripheral surface and outer peripheral surface) of the sleeve, the problems of the conventional metal sleeve can be avoided. Specifically, a first aspect of the invention, a cylindrical metal sleeve in which slits are formed in the longitudinal direction, the
With three tongues with slits projecting alternately in the circumferential direction
The bent ferrule inserted in the sleeve.
The optical fiber connection sleeve is characterized in that the three tongue pieces are held so as to be held and the inner peripheral surface of the three tongue pieces is formed with a protective coating having high surface hardness and corrosion resistance. Solved.

According to the present invention, the ferrules are staggered.
Hold it from the left and right with the three tongues protruding to the left
A stable fit is obtained for holding. Further, by forming a protective coating on the inner peripheral surface of the metal sleeve, the surface of the sleeve is improved, and it is possible to prevent discoloration or corrosion of the surface. In addition, dust and metal powder are less likely to adhere to the surface of the sleeve, and the surface of the ferrule does not become black, so that communication performance is not impaired.

According to a second aspect of the present invention , in the optical fiber connecting sleeve according to the first aspect, the protective coating is formed by plating.

According to the present invention, the protective film can be formed by a simple means. As the plating method, for example, electroplating, chemical plating, metal spraying method, room temperature diffusion / permeation plating, etc. can be used.

According to a third aspect of the present invention , in the optical fiber connecting sleeve according to the third aspect, the protective coating is a metal plating layer or a ceramic alloy layer.

According to the present invention, the surface hardness and the corrosion resistance can be enhanced, and the properties equivalent to those of the conventional sleeve made of zirconia ceramics can be obtained.

[0012] A fourth aspect of the present invention, a method of molding by pressing a cylindrical metal sleeve in which slits are formed in the longitudinal direction from the flat plate, the sleeve from the plate
In the process of punching out the outer shape of, the center of one side of the work
While the first tongue piece is formed to project on the part, the
The second and third tongue pieces are respectively formed to project, and then the work piece
After forming a protective film with high surface hardness and corrosion resistance on the
The punched work is bent into a cylindrical shape, and the first tongue is formed.
A method for manufacturing an optical fiber connecting sleeve is characterized in that a piece is fitted between a second tongue piece and a third tongue piece .

According to the present invention, by adopting the press working, the first, second and third tongue pieces can be attached to a flat work piece.
It can be easily molded, and a protective film having high surface hardness and high corrosion resistance can be easily formed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an optical fiber connecting sleeve according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG . 2 shows an implementation of the sleeve 16 according to the present invention.
It shows the morphology. Sleeve according to this embodiment
16 bends the slit 17 with respect to its length direction
It was formed. That is, in the sleeve 16 in the circumferential direction
Three tongue pieces 20a, 20b, 20c protruding alternately
By providing the curved slit 17
Is made. The sleeve 16 has such a slit 17
The tongue piece 20 when the ferrule is inserted.
a, 20b, 20c hold from both sides with an appropriate spring force
Since it is held like this, stable mounting of the ferrule is possible
Becomes

The sleeve 16 has a structure as shown in FIG.
Concavo-convex shape forming the outer shape of the sleeve 16 from the strip-shaped flat plate 10
It is formed by punching the work 18 in the shape of a circle. Immediately
Then, in the punching process, the left side of the work 18
While forming the first tongue piece 20a in the central part, in the right center part
Corresponding recesses 21a are formed. Also, the recess 2 1
On both sides of a, second and third similar to the first tongue piece 20a.
While forming the tongue pieces 20b and 20c respectively, the left side
On both sides of the first tongue piece 20a in the central portion, the second and third
Insert the recesses 21b and 21c corresponding to the tongue pieces 20b and 20c.
Each is formed. Punched in this way
By bending the formed work 18 into a cylindrical shape,
The first tongue piece 20a fits into the recess 21a,
Then, the second and third tongue pieces 20b, 20c are formed into the recesses 21b, 2
1c, and each of the
Forming a sleeve 16 with a curved slit 17
You can

FIG. 1 shows the progressive transfer of the sleeve having the above structure .
The pressing steps are shown in order. In step 1, a pair of pilot holes 11 are formed in a strip-shaped plate 10 made of phosphor bronze.
a, 11b are provided, steps 2 and 3 are a step of punching the strip-shaped flat plate 10 into a rectangular shape to form the outer shape of the work 13 connected to the frame 12 at two points, and steps 4 to 6 are the work 13 Is gradually bent to form a cylindrical sleeve 15 having a linear slit 14, and step 7 is a step of cutting two portions connected to the frame 12 to separate the sleeve 15. Na
Oh, here the sleeve 1 with the linear slit 14
The molding process of No. 5 will be described.
The same applies to the sleeve 18 with the flexible slit 17
It is obtained by the molding process of.

In the present invention, a protective coating is formed on the work 13 between the steps 3 and 4. At this stage, work 13
Since a flat surface is secured, it is easy to form a protective film, and a protective film having a uniform thickness can be formed on both surfaces of the work 13. Therefore, in the progressive press step, when the step 3 is completed, the press work is temporarily interrupted and the protective film formation step is performed. After the step is completed, the step is returned to the step 4 of the progressive press step and the remaining steps are performed. 7, the sleeve 15 having the protective coating formed on the surface (the inner peripheral surface and the outer peripheral surface of the cylinder) is molded.

Metal plating is a typical method for forming the protective film, but non-metal such as ceramics may be plated. Plating is performed variously for the purpose of improving the properties of the metal surface to be plated such as increasing the surface hardness and smoothing the surface, but since both methods are performed on the flat metal surface, the cylindrical body is used. Unlike plating, the entire surface is coated with a uniform film thickness,
It can also be finished extremely smoothly. In the present invention, electroplating, chemical plating, metal spraying, room temperature diffusion / permeation plating, etc. can be adopted as the metal plating treatment method. In addition, non-metals such as ceramics can be plated using room temperature diffusion / penetration plating.

In electroplating, the surface of the sleeve 15 can be plated with gold, silver, nickel, or chrome. Since gold plating is soft as it is, it is desirable to plate it as an alloy with silver or copper. Further, since the silver plating remains black as it is attacked by sulfides, it is desirable to further thinly plate rhodium thereon. On the other hand, the nickel plating can be easily plated by stacking it on the copper plating. In addition, chrome plating has a particularly large surface hardness, and has high wear resistance and heat resistance.

On the other hand, the chemical plating utilizes substitution due to the difference in the ionization tendency of metals and chemical reduction with a reducing agent,
It is a method of plating metal without relying on an electric field, and is used when nickel plating, chromium plating, or the like is performed. As the reducing agent, sodium hypophosphite is widely used. In both the above electroplating and chemical plating, plating is performed by continuously passing the work 13 having completed the above steps 3 to the frame 12 in a plating bath filled with a plating solution. The hoop plating method is used.

Further, in the metal spraying method, metal powder or metal wire is melted at the nozzle portion of the sprayer and blown off by using compressed air or hydrogen gas, and a metal protective film is attached and solidified on the surface of the work 13. It is a method to let. The metal material used as the metal powder or the metal wire has a hardness equal to or higher than the phosphor bronze hardness.

In the room temperature diffusion / permeation plating method, metal powder or ceramic powder is sprayed onto the surface of the work 13 at a high speed to raise the surface temperature, and the elements in the composition of the metal powder or ceramic powder are added to the work. The surface hardness and corrosion resistance can be increased by diffusing and permeating the metal surface of 13 and forming an alloy layer on the surface. In particular, when the ceramic powder is used, an alloy layer with the ceramic is formed, so that it is possible to obtain the same properties as the sleeve made of the conventional zirconia ceramics. Note that chromium or cobalt is used as the metal powder, and zirconia or alumina is used as the ceramic powder.

In the above-mentioned plating step, a hard metal plating layer is applied to the surface of the work 13 to a uniform thickness or a ceramic alloy layer is formed, so that this is returned to the progressive pressing step again from step 4. The metal plating layer and the alloy layer do not peel off from the surface of the sleeve 15 when the bending process in Step 6 is performed. Therefore, after such a plating process, even if the original material is phosphor bronze, the surface is not discolored or corroded even after long-term use, and the surface hardness is high and smooth. Therefore, metal powder of phosphor bronze, dust, and the like are less likely to adhere to the outer peripheral surface of the ferrule.

In the above-mentioned embodiment, the case where the metal plating layer or the ceramic alloy layer is applied to the surface of the work 13 during the press working process has been described, but at the stage of the strip-shaped plate material 10 before entering the press working process. It is also applied when the above-mentioned plating process is completed. Even in this case, the metal plating layer is not peeled off by the punching process from the pressing step 1 to the pressing step 3. The present invention is also applied to the case where the protective coating is formed on the surface of the sleeve 15 by means other than the above-mentioned plating.

[0026]

As described above, according to the optical fiber connecting sleeve of the present invention, the ferrules are staggered.
Hold it from the left and right with the three tongues protruding to the left
In order to hold a stable mounting is obtained. Further, since the protective coating having high surface hardness and high corrosion resistance is formed on the inner peripheral surface of the sleeve, the metal surface of the sleeve is improved and discoloration or corrosion of the surface can be prevented. Furthermore, dust and metal powder are not easily attached to the surface of the sleeve, and the surface of the ferrule is not blackened, so that communication performance is not impaired.

Further, according to the method of manufacturing the optical fiber connecting sleeve of the present invention, the sleeve is formed by pressing.
Three tongue pieces for forming slits by molding
Can be easily processed into a flat work piece.
In addition, a protective film with high surface hardness and corrosion resistance can be easily and reliably
Can be formed.

[Brief description of drawings]

1 is a process diagram of a pressing of the optical fiber connection sleeve according to the present invention.

It is a perspective view of an optical fiber connection sleeve according to the invention; FIG.

FIG. 3 is a diagram showing a step of press working of the optical fiber connecting sleeve shown in FIG. 2;

FIG. 4 is a perspective view showing a general usage example when connecting an end portion of an optical fiber to a sleeve.

[Explanation of symbols]

10 band flat plate 12 frames 13,18 Work 14,17 slits 15, 16 sleeve20a, 20b, 20c tongue 21a, 21b, 21c Recess

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B 6/38

Claims (4)

(57) [Claims] 1. A cylindrical metal sleeve having slits formed in the lengthwise direction , wherein the slits are circumferentially aligned with each other.
It is bent and formed by three tongues protruding differently,
Hold the ferrule inserted in the sleeve with the three tongue pieces
To prevent the surface hardness and corrosion resistance of the inner peripheral surface.
A sleeve for connecting an optical fiber, which is formed with a protective coating having high properties . 2. The optical fiber connecting sleeve according to claim 1, wherein the protective film is formed by plating. 3. The optical fiber connecting sleeve according to claim 2, wherein the protective coating is a metal plating layer or a ceramic alloy layer. 4. A method of forming a tubular metal sleeve having a slit formed in the length direction from a flat plate by press working, in the step of punching and forming the outer shape of the sleeve from the flat plate,
A projecting first tongue piece is formed at the center of one side of the workpiece.
The second and third tongue pieces on both sides of the
And then protect the work with high surface hardness and corrosion resistance
After forming the film, bend the punched work into a tubular shape.
And molding the first tongue into a second tongue and a third tongue.
A method for manufacturing an optical fiber connecting sleeve, characterized in that the optical fiber connecting sleeve is fitted in between .