JPH09133837A - Optical fiber connector and ferrule for optical fiber connector and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of an optical fiber connector and to simplify its production stages. SOLUTION: This connector is provided with one end 2a side of a fiber insertion hole 2 as a holding hole 200 of a fine hole. The part from this holding hole 200 to the other end 2b side of the fiber insertion hole 2 is formed as a diameter expanding part 201 of the diameter larger than the diameter of the holding hole 200. The other end 2b of the insertion hole is provided with three projecting parts 3 on its inside wall. These projecting parts 3, 3, 3 are used as a reference for contact of a center jig 7 at the time of executing the outside diameter grinding of a ferrule body 1 after injection molding of this ferrule body. As a result, the three-points contact of the center jig 7 is surely obtd. through the contact of the center jig 7 and the projecting parts 3, 3, 3 even if the ferrule body 1 prior to the outside diameter grinding is not subjected to any working at all after the injection molding. The working of the center hole at the other end 2b of the insertion hole to be previously executed before the outside diameter grinding is thus omitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule known as an optical fiber connector component and a method for manufacturing the ferrule.

[0002]

2. Description of the Related Art Conventionally, as this type of optical fiber connector, there is known an optical fiber connector having a ferrule formed by injection molding having a shape as shown in FIG.

The ferrule shown in FIG. 13 comprises a ferrule main body 1, and the entire fiber insertion hole 2 of the ferrule main body 1 is provided in a slender shape with a diameter substantially the same as that of an optical fiber element wire from the time of injection formation. When an optical fiber element wire is inserted into the fiber insertion hole 2 from its entrance, the optical fiber element wire is positioned and fixed and centered and held in the entire fiber insertion hole 2, and the optical fiber element wire is precisely held. It

As a manufacturing process of the ferrule shown in the figure, a series of steps 300 to 306 as shown in FIG. 14 are known.

In the step (molding) 300, as shown in FIG. 15 (a), the ferrule body 1 (see FIG.
The ferrule material 1-1, which is the basis of the reference), is molded.
The ferrule material 1-1 is formed in a columnar shape, and is provided so that a pilot hole 2-1 for inserting an optical fiber penetrates between both end faces thereof. The prepared hole 2-1 is the basis of the fiber insertion hole 2.

In the process (inner diameter polishing) 301, a plurality of ferrule materials 1-1,
All the prepared holes 2-1 are polished at the same time by bundling 1-1 ... (See FIG. 15B).

For this inner diameter polishing, the setting wire 13 is passed through the prepared hole 2-1 to set a plurality of ferrule materials 1-1 on the wire 13, and the plurality of ferrule materials 1-1, 1-1. A set body 14 made of ... Is loaded into a cylinder body (sheath) 15, an adhesive 16 such as solder or a rack is injected into the cylinder body 15 to position and fix the set body 14, and from the set body 14. The work of pulling out the wire 13 is sequentially performed. Next, the polishing taper wire 12 (a wire having a larger diameter in the longitudinal direction and a constant diameter in the latter half) is inserted into the prepared hole 2-1 from the end face side of the tubular body 15. After that, the cylindrical body 15 is rotated around the axis, and while the loose abrasive grains 10 are sequentially attached and supplied to the taper wire 12 before the ferrule material 1-1, the taper wire 12 is pulled out in the axial direction and wound on a reel (not shown). Meanwhile, the prepared hole 2-1 is polished. The adhered supply of the loose abrasive grains 10 is performed by hanging or dipping the liquid free abrasive grains 10 on the tapered wire 12.

In other words, the inner diameter polishing is performed on the basis of a bare hole, which is based on a prepared hole that has not been processed after molding.

After polishing, the adhesive 16 is removed and all the ferrule materials 1-1, 1-1 ... Are removed from the cylindrical body 15.

Process (outer diameter grinding [centerless method]) 30
In No. 2, from the viewpoint of efficiently removing the outer diameter machining allowance of the ferrule material 1-1, the ferrule material 1-1 after inner diameter polishing is set on a centerless support device or the like, and the outer diameter portion of the ferrule material 1-1 is set. Centerless grinding of 1-1c (see FIG. 15C).

In the step (end face grinding) 303, both end faces 1-1a and 1-1b of the ferrule material 1-1 are roughly ground (see FIG. 15 (d)).

Process (Outer Diameter Grinding [Both Center Method]) 304
Then, from the viewpoint of removing the outer diameter of the ferrule material 1-1 and the eccentricity of the prepared hole 2-1 to make them coaxial, FIG.
As shown in (e), the outer diameter portion 1 of the ferrule material 1-1.
Grind for -1c. In such outer diameter grinding, the ferrule material 1-1 is supported at both centers. Both center supports are 1-1a on both sides of the end surface of ferrule material 1-1,
The center jigs 6 and 7 are brought into contact with the prepared hole 2-1 from 1-1b, whereby the ferrule raw material 1-1 is brought into contact with both end surfaces 1-1.
It shall be supported from a, 1-1b.

In step (outer diameter polishing) 305, the outer diameter portion 1-1c of the ferrule material 1-1 is polished to a desired roughness (see FIG. 15 (f)).

In the step (end surface processing) 306, processing such as making the end surface of the ferrule material 1-1 into a convex spherical surface is performed (FIG. 1).
5 (g)).

In the step (molding) 300, as shown in FIG.
As shown in (a), a reference step portion 17 is provided at the inlet 2-1b of the prepared hole 2-1 during injection molding of the ferrule material 1-1. It is used temporarily as a contact reference of the center jig 7 during outer diameter grinding by the grindstone 12 of outer diameter grinding [both center method] 304. Therefore, after finishing the outer diameter grinding, the reference step portion 1
From the viewpoint of preventing damage to the optical fiber strand due to 7,
V machining on the prepared hole inlet 2-1b side (see FIG. 16 (b))
Or R-working (see FIG. 16 (c)), etc., to scrape off the reference step portion 17 to make the pilot hole inlet 2-1b, that is, the inlet of the fiber insertion hole 2 into a smooth mortar shape without corners. Shall be finished.

On the other hand, the ferrule shown in FIG. 18 pays attention to the fact that the optical fiber element wire can be sufficiently positioned and fixed and the centering and holding (precision holding) can be performed only with the inner part (one end side) 2a of the fiber insertion hole 2. This is configured from the viewpoint of reducing the finishing processing amount of the fiber insertion hole 2.

That is, in this ferrule, only the inner portion (one end side) 2a of the fiber insertion hole 2 is provided with a diameter substantially equal to that of the optical fiber strand from the time of injection formation, and other than this, it is sufficiently larger than the diameter of the optical fiber strand. When the optical fiber element wire is formed in a large diameter and is inserted into such a fiber insertion hole 2, positioning and fixing of the optical fiber element wire is performed not only in the entire fiber insertion hole 2 but only in the inner part (one end side) thereof. Centered and held.

[0018]

However, the above-mentioned conventional ferrule has the following problems.

Since the conventional ferrule shown in FIG. 13 has a structure in which the optical fiber element wire is positioned and fixed in the entire fiber insertion hole 2, finishing processing for positioning and fixing is required in the entire fiber insertion hole 2. Its processing amount,
The processing time is long, the ferrule manufacturing time is long, and it takes time to complete the manufacturing of the optical fiber connector.

Moreover, according to the conventional ferrule shown in FIG.
Since the fiber insertion hole 2 is long and thin,
The fiber insertion hole 2 is bent at the time of injection molding, and an extra step for correcting the bending is required. Further, from the viewpoint of preventing damage to the optical fiber element wire, the fiber insertion hole 2
Since a secondary machining such as V machining and R machining is required at the entrance of the optical fiber connector, the number of manufacturing steps of the optical fiber connector also increases, and it takes time to complete the manufacturing and the manufacturing cost increases.

The conventional ferrule shown in FIG. 18 has the structure shown in FIG.
As shown in FIG. 6, the other end 2b of the fiber insertion hole 2 with which the center jig 7 abuts during outer diameter grinding is injection-molded, so that the contour has many irregularities and the hole accuracy of the other end 2b of the fiber insertion hole is poor. Therefore, the contact between the center jig 7 and the other end 2b of the fiber insertion hole is unstable, and the accuracy of the outer diameter grinding (roundness of the ferrule outer diameter, concentricity of the ferrule outer diameter and the fiber insertion hole, etc.) This leads to deterioration and an accurate optical fiber connector cannot be obtained.

In order to avoid such a problem, it is conceivable to finish the other end 2b of the fiber insertion hole to a predetermined dimensional accuracy before the outer diameter grinding, that is, to perform so-called center hole machining. If such additional center hole processing is newly added, the number of manufacturing processes of the optical fiber connector increases, the manufacturing completion takes time, and the manufacturing cost increases.

Further, according to the conventional ferrule shown in FIG. 18, since there is a step 18 on the inner side of the fiber insertion hole 2 due to the difference in diameter between the inner side and other portions, the step 18 is sharply formed at the time of injection molding. Because of a change in the step area, a nest (inner sink) is generated around the step 18, and the positioning portion (the inner part of the fiber insertion hole 2 (one end 2a side)) ahead of the step 18 does not have a desired shape. , The accuracy of positioning and fixing the optical fiber and the centering and holding are poor. Therefore, a highly accurate optical fiber connector cannot be obtained, and the reliability of optical communication is lowered. Further, burrs are apt to be formed on the step, and the optical fiber strands are damaged by such burrs. In this respect as well, it is not possible to expect a highly accurate optical fiber connector and highly reliable optical communication.

The conventional ferrule manufacturing method as described above has the following problems.

In the conventional manufacturing method, as shown in FIG. 15 (b), the ferrule material 1 in the step (inner diameter polishing) 301 is used.
Since the positioning and fixing of -1 is performed by the adhesive 16, the work of injecting and setting the adhesive 16 as a preparatory step for the inner diameter polishing and the work of removing the adhesive 16 as a subsequent preparatory step are required. Since it is necessary to rely on human labor, it takes time for the setup work, the entire manufacturing time of the ferrule becomes long, it takes time to complete the manufacturing of the optical fiber connector, and it is difficult to fully automate the manufacturing process.

Moreover, in the positioning and fixing with the adhesive 16 as described above, the set state of the ferrule material 1-1 is collapsed due to the shrinkage of the adhesive 16 or the like, and the ferrule material 1-1 and the prepared hole 2-1 are formed into the cylindrical body 15. On the other hand, it will fall at an angle, the setting accuracy will decrease, and the processing conditions for inner diameter polishing will deteriorate. Therefore, desired processing accuracy cannot be obtained. Also, the adhesive 1
In No. 6, since the set state collapses as described above and the overall balance of the tubular body 15 is not good, the tubular body 15 cannot rotate at high speed, and the machining efficiency cannot be improved.

In the conventional manufacturing method, the prepared hole 2-1 formed by molding, the eccentricity of the outer diameter of the ferrule material, and the parallelism are not at the desired accuracy, and the inner diameter polishing in step 301 is processed after molding. Since the prepared hole 2-1 is used as a reference, the inner diameter is polished irrespective of the outer diameter of the ferrule material, so that the eccentricity of the prepared hole 2-1 with respect to the outer diameter of the ferrule material after the inner diameter is polished. The parallelism is not corrected, and the eccentric or inclined pilot hole 2-1 expands as it is.
Therefore, not only the eccentricity and inclination due to the molding error in the process 300, but also the eccentricity and the spread of the inclined pilot hole 2-1 must be expected in advance, and an extra large outer diameter allowance of the ferrule material 1-1 must be provided. Without spending time to remove it,
The entire manufacturing time of the ferrule becomes long, and it takes time to complete the manufacturing of the optical fiber connector. In addition, the molding material of the ferrule material 1-1 is required, and the manufacturing cost of the optical fiber connector increases. Further, after the inner diameter polishing, an additional step 304 for removing such inclination and eccentricity is required.

According to the conventional manufacturing method, the ferrule material 1-1 has a large outer diameter allowance as described above, and in the case of supporting both centers in step 304, since the prepared hole 2-1 has a small diameter, the center jig is thin. Since the machining efficiency is poor, a separate step for efficiently removing the outer diameter machining allowance is required. In this sense, the centerless type outer diameter grinding which is excellent in machining efficiency is adopted as the step 302 between the step 301 and the step 304. However, the centerless method has a poor ability to reduce the eccentricity, Since the air cut for the eccentricity must be set at the time of machining in step 304, step 3
The processing time of 04 cannot be shortened significantly, and the entire manufacturing time of the ferrule has not been shortened.

In order to correct the eccentricity of the pilot hole 2-1,
Although it is conceivable to apply wire centerless type outer diameter grinding in place of the centerless type in step 302,
According to such a wire centerless method, setup work such as the work of setting the ferrule material 1-1 on the wire is required for a long time, unmanned operation is difficult, and an increase in manufacturing cost is unavoidable.

In the conventional manufacturing method, particularly when the prepared hole has a tapered shape like a nozzle as shown in FIG. 18, the ferrule material 1-1 as shown in FIG. Is tilted and set on the setting wire 13, and the ferrule material 1 is attached to the wire 13.
It is difficult to set -1 in parallel with high accuracy, and the deterioration of processing accuracy becomes even more serious.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical fiber connector suitable for improving the accuracy of the optical fiber connector and simplifying the manufacturing process thereof. Providing a ferrule suitable for improving the reliability of optical communication, simplifying the ferrule manufacturing process, shortening the manufacturing time, etc., shortening the ferrule manufacturing time, fully automating the manufacturing process, improving processing accuracy, etc. To provide a ferrule manufacturing method suitable for achieving the above, and particularly for a ferrule material having a tapered shape such as a nozzle (see FIG. 8), the parallelism and eccentricity accuracy of the prepared hole after polishing the inner diameter with respect to the outer diameter of the ferrule material Provide a ferrule manufacturing method that is effective for improvement, and provides a ferrule manufacturing method suitable for reducing ferrule cost, shortening the manufacturing time, and the like. In the door.

[0032]

In order to achieve the above object, firstly, the present invention is an optical fiber connector comprising a ferrule body for centering and holding an end portion of an optical fiber wire. In the ferrule body, one end side is formed of a holding hole having a hole diameter for holding the outer peripheral surface of the optical fiber strand, and the other end side is provided with a fiber insertion hole communicating with the holding hole as a larger diameter portion than the holding hole. It is characterized in that a plurality of protrusions serving as a contact reference of a center jig used when grinding the outer diameter of the ferrule body are formed on the inner wall of the other end of the fiber insertion hole.

Secondly, the present invention is characterized in that the surface shape of the protruding portion is a curved surface.

Thirdly, the present invention is a ferrule for an optical fiber connector comprising a ferrule body having a fiber insertion hole for inserting an optical fiber, wherein the inner side of the fiber insertion hole is the optical fiber. It is characterized in that it is formed as a positioning portion for a narrow hole that is in close contact with the outer peripheral surface, and the inlet side of the fiber insertion hole is provided as a skirt widening portion that spreads smoothly from the positioning portion.

Fourthly, the present invention uses a cylindrical ferrule material in which a prepared hole for inserting an optical fiber penetrates between the end faces, and rough-grinds the outer diameter of this ferrule material to obtain the outer diameter and lower diameter of the ferrule material. After removing the eccentricity of the holes, place multiple eccentricity-removed ferrule materials in the cylindrical holder to position and fix them in a column, and then from the end surface side of the cylindrical holder to the prepared hole It is characterized in that free abrasive grains are inserted to polish the prepared hole.

Fifthly, the present invention uses a cylindrical ferrule material in which a prepared hole for inserting an optical fiber penetrates between the end surfaces, and a center jig is brought into contact with the prepared hole from both end surfaces of the ferrule material. By doing this, the outer diameter of the ferrule material is roughly ground by supporting both ends of the ferrule material with center jigs to remove the eccentricity and inclination of the outer diameter of the ferrule material and the pilot hole. After polishing the prepared hole of the ferrule material based on the outer diameter of the material, the center jig is brought into contact with the prepared hole from both sides of the end surface of the ferrule material, thereby supporting the ferrule material from both end surfaces with the center jig. It is characterized in that the outer diameter finish grinding of the ferrule material is performed by both center supports.

Sixth, the present invention is characterized in that the end face rough grinding of the ferrule material is performed in advance before the outer diameter rough grinding.

Seventh, the present invention, after the outer diameter finish grinding,
It is characterized in that the end surface of the ferrule material is ground.

Eighth, the present invention is characterized in that the end face rough grinding and the end face finish grinding of the ferrule material are performed before the outer diameter rough grinding or after the outer diameter finish grinding.

According to the present invention, when the outer diameter of the ferrule body is ground, the center jig is brought into contact with the convex portion of the contact reference instead of the hole entrance having a contour with unevenness after injection molding. Even if the ferrule before diameter grinding is not processed, the three-point contact of the center jig can be surely obtained through the contact between the center jig and the convex portion.

In the present invention, since the skirt expanding portion smoothly extends from the positioning portion to the inlet side of the fiber insertion hole, it is possible to perform injection molding of the ferrule body, etc.
Nest (inner sink) or burr is less likely to occur in the fiber insertion hole,
The burr does not damage the optical fiber, and the secondary processing for preventing such damage can be omitted, and the optical fiber element wire is inserted into the fiber insertion hole without performing the secondary processing. It becomes possible.

According to the present invention, the plurality of ferrule materials from which the eccentricity has been removed are positioned and fixed on the basis of the outer diameter by abutting on the cylindrical holder, and the prepared hole is ground with the outer diameter of the ferrule material as a processing reference.

According to the present invention, the eccentricity and inclination of the outer diameter of the ferrule material and the prepared hole are removed by grinding the outer diameter in advance before polishing the prepared hole. Therefore, when setting the outer diameter allowance of the ferrule material, it is only necessary to consider only the eccentricity and inclination of the molding error that occur at the stage of molding the ferrule material,
The outer diameter allowance of the ferrule material can be minimized.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to FIGS.

The optical fiber connector has a ferrule as a means for centering and holding the end portion of the optical fiber element wire.

The ferrule comprises a ferrule body 1 having a shape as shown in FIG. 1. The ferrule body 1 is provided with a fiber insertion hole 2 for centering and holding an end portion of an optical fiber element wire (not shown). Has been.

The one end 2a side of the fiber insertion hole 2 serves as a holding hole 200 for the pore, and the portion between the holding hole 200 and the other end 2b side of the fiber insertion hole 2 has a larger diameter portion than the holding hole 200. It is formed as 201.

The holding hole 200 is constructed so as to be in close contact with the outer peripheral surface of the optical fiber element wire and hold the outer peripheral surface of the optical fiber element wire through this contact, while the expanded diameter portion 201 is formed from a tapered hole with a widened bottom. The holding hole 200 is formed so as to spread smoothly toward the other end 2b side of the fiber insertion hole 2.

That is, the holding hole 200 has a diameter for holding the outer peripheral surface of the optical fiber element wire, and the expanded diameter portion 201 is closer to the other end 2b of the fiber insertion hole 2 than the boundary with the holding hole 200. The diameter gradually expands toward the other end 2b of the insertion hole so that the diameter becomes maximum.

The other end 2b of the fiber insertion hole 2 is opened like a mortar, and the inner wall thereof has three protrusions 3 along the wall surface.
3 and 3 are provided, the surface of each of these protrusions 3, 3 and 3 is formed into a curved surface, and the tops 3a and 3a are provided.
a and 3a are provided so as to face the central axis side of the fiber insertion hole 2.

The protrusions 3, 3, 3 are used as a contact reference of the center jig 7 when the outer diameter of the ferrule body 1 is ground after injection molding, and the protrusion 3,
How 3 and 3 work will be described later.

In such a ferrule, when the end portion of the optical fiber element wire is inserted from the other end 2b side of the fiber insertion hole 2, the optical fiber element wire is brought into close contact with the holding hole 200, and this close contact causes the optical fiber to come into contact with the optical fiber. The fiber strand is centered and held and positioned and fixed, and the end portion of the optical fiber strand is precisely held.

To manufacture the ferrule having the above structure, the mold 4 and the core pin 5 as shown in FIG. 2 are used.

The mold 4 is provided with a cavity 400 for forming the contour of the ferrule body 1, while the core pin 5 is provided with an insertion hole shape portion 500 having substantially the same shape as the fiber insertion hole 2. .

When the ferrule body 1 is manufactured by using the mold 4 and the core pin 5 as described above, the cavity 4 of the mold 4 is used.
After the core pin 5 is inserted into 00, the insertion hole shape portion 500 of the core pin 5 is positioned and fixed at a fixed position in the cavity 400, the ferrule material is injection-filled into the cavity 400, and the ferrule body 1 is injection-molded.

Thereafter, as shown in FIG. 1, from the viewpoint of removing the eccentricity of the ferrule body 1 and the eccentricity of the fiber insertion hole 2 to make them coaxial, the ferrule body 1 is subjected to outer diameter grinding.

At this time, the ferrule body 1 is supported by both centers. Both center supports support the ferrule body 1 from both end surfaces 1a, 1b by a pair of left and right center jigs 6, 7.

When carrying out such center support, by inserting a center jig into the fiber insertion hole 2 from both end surfaces 1a, 1b of the ferrule body 1, the left center jig 6 contacts one end 2a of the fiber insertion hole 2. Contact, right center jig 7
Contacts the protrusions 3, 3, 3 on the other end 2b side of the fiber insertion hole 2.

That is, the right center jig 7 and the other end 2b side of the fiber insertion hole 2 are in contact with each other at three points around the circumference of the right center 7 through the convex portions 3, 3, 3.

After finishing the outer diameter grinding under the support of both centers as described above, other processing such as polishing of the fiber insertion hole 2 is performed to obtain a ferrule as a final product.

According to the ferrule of this embodiment, three protrusions 3, 3, 3 are provided on the inner wall of the other end of the fiber insertion hole 2, and these are brought into contact with the center jig 7 when the outer diameter of the ferrule body 1 is ground. It is a standard. For this reason, when the outer diameter of the ferrule body 1 is ground, not the hole entrance whose contour is uneven due to the completion of injection molding, but the protrusions 3, 3, 3 which are the contact reference.
Since the center jig 7 comes into contact with the center jig 7, the contact state of the center jig 7 is stabilized, and the accuracy of outer diameter grinding (roundness of the ferrule outer diameter, coaxiality between the ferrule outer diameter and the fiber insertion hole, etc.) is improved. However, the precision of the ferrule can be improved, and an accurate optical fiber connector can be obtained through this.

Further, according to this ferrule, the center jig 7 and the protrusions 3, 3, 3 are brought into contact with each other by the contact between the center jig 7 and the protrusions 3, 3 and 3 after the injection molding but before the outer diameter grinding and without any processing. Since the three-point contact of the tool 7 is surely obtained,
Since it is not necessary to finish the other end 2b of the fiber insertion hole 2 to a predetermined dimensional accuracy before the outer diameter grinding, the center hole machining for the finishing can be omitted, and the ferrule manufacturing process is reduced accordingly. It is possible to simplify the manufacturing process of the optical fiber connector and reduce the manufacturing cost.

In particular, in this ferrule, since the protrusions 3, 3, 3 are spherical, even if the protrusions 3, 3, 3 are left as they are, the protrusions 3, 3, The optical fiber bare wire is not damaged by 3, and the secondary process for preventing damage, for example, the conventional V-cutting process, R-attaching process, etc., can be omitted at all, which also simplifies the manufacturing process. And the manufacturing cost can be reduced.

Further, according to this ferrule, the contact between the center jig 7 and the other end 2b side of the fiber insertion hole 2 is three-point contact, and the contact resistance is small. It is also possible to increase the machining efficiency and improve the machining efficiency.

The number of contact points between the center jig 7 and the other end 2b of the fiber insertion hole 2 is 3 due to the stability of the contact.
Three-point contact is made through the three protruding portions 3, 3, 3. Therefore, if stable contact can be obtained, the number of protrusions 3, 3, 3 is increased to three or more, and the center jig 7 and the other end 2b side of the fiber insertion hole 2 are contacted at three or more points. Alternatively, the number of protrusions can be changed as appropriate.

As shown in FIG. 3, the expanded diameter portion 201 is not a tapered hole but a holding hole 200 to a fiber insertion hole 2.
It is also possible to form a hole having the same diameter up to the other end 2b side.

The shape of the protrusions 3, 3, 3 is the center jig 7.
This can be applied as long as it has a point contact in the circumferential direction with, and is not limited to a curved surface. However,
It is necessary to make the shape so that the core pin 5 can be pulled out at the time of injection molding. The protrusions 3, 3, 3 may be removed after the outer diameter grinding is completed.

FIG. 4 shows an embodiment of a ferrule according to the present invention. The ferrule shown in FIG. 4 comprises a ferrule body 1, and a fiber for inserting an optical fiber element wire (not shown) into the ferrule body 1. An insertion hole 2 is provided.

A deep hole 2a side of the fiber insertion hole 2 is provided as a fine hole positioning portion 202, and an entrance 2b side of the fiber insertion hole 2 is provided as a skirt widening portion 203. The positioning portion 202 is provided with the holding hole 200 ( (See FIG. 1), the optical fiber element wire is brought into close contact with the outer peripheral surface of the optical fiber element wire, the optical fiber element wire is positioned and fixed through this adhesion, and the hem widened portion 203
Is formed so as to spread smoothly from the positioning portion 202 toward the entrance 2b side of the fiber insertion hole 2, and its spread is a curved spread with a large curvature.

That is, the positioning portion 202 is formed to have substantially the same diameter as the optical fiber strand, while the skirt widening portion 203 gradually widens from the boundary with the positioning portion 202 toward the fiber insertion hole entrance 2b side. It is provided so that the diameter becomes maximum on the fiber insertion hole inlet 2b side.

FIG. 5 shows how to make such a ferrule.
A mold 4 and a core pin 5 as shown in are used.

The mold 4 is provided with a cavity 400 for forming the contour of the ferrule body 1, while the core pin 5 is provided with an insertion hole shaped portion 500 having substantially the same shape as the fiber insertion hole 2. .

To manufacture a ferrule using the mold 4 and the core pin 5 as described above, the cavity 400 of the mold 4 is used.
Insert the core pin 5 into the insertion hole shaped portion 50 of the core pin 5.
After 0 is positioned and fixed at a fixed position in the cavity 400, the ferrule material is injection-filled in the cavity 400.

In the ferrule thus produced, when the optical fiber element wire is inserted from the entrance 2b side of the fiber insertion hole 2, the optical fiber element wire is positioned by the positioning portion 202.
In this case, the optical fiber element wire is closely attached to the fiber insertion hole 2, and the optical fiber element wire is positioned and fixed by this close contact.

In the ferrule of this embodiment, a skirt widened portion 203 is smoothly widened from the positioning portion 202 to the inlet 2b side of the fiber insertion hole 2. Therefore, during injection molding of the ferrule body 1 or the like, cavities (inner sinks) and burrs are less likely to occur in the fiber insertion hole 2, the positioning portion 202 can be finished in a desired shape, and the positioning fixing accuracy of the optical fiber strands can be improved. Will improve,
Also, the reliability of optical communication can be improved in that damage to the optical fiber strand due to burrs can be prevented. Also,
Secondary processing (burring processing, V cutting processing, R mounting processing, etc.) for preventing such scratches can be omitted, and the optical fiber strand to the fiber insertion hole 2 can be omitted without performing secondary processing. Since it is possible to insert the ferrule, the ferrule manufacturing process can be simplified, the manufacturing time can be shortened, the manufacturing cost can be reduced, and the like.

According to this ferrule, only the inner portion 2a side of the fiber insertion hole 2 is formed as the positioning portion 202. For this reason, since the finishing process for positioning and fixing is not required for the entire fiber insertion hole 2 but only for the positioning portion 202, the finishing processing amount and processing time are reduced, and in this respect also, the ferrule manufacturing time can be shortened. The cost can be reduced.

Further, according to this ferrule, only the positioning portion 202 of the fiber insertion hole 2 is a fine hole. For this reason, a part of the fiber insertion hole 2 is a fine hole, and the length of the fine hole is short. Therefore, when the ferrule body 1 is injection-molded, the fiber insertion hole 2 can be bent as much as possible. Decrease. Therefore, the process for correcting such hole bending can be omitted, and the ferrule manufacturing process can be simplified. In this respect as well, the ferrule manufacturing time and the manufacturing cost can be reduced.

Note that the spread of the skirt expanding portion 203 is not curved, but may be linear as shown in FIG. In this case, the skirt expanding portion 203 and the positioning portion 20
No. 2 is connected by a curved surface, that is, it is preferable to provide a curved surface portion 204 having no corners at the boundary between the skirt widening portion 203 and the positioning portion 202, because there is no catching or scratching when the fiber is inserted.

FIG. 7 shows an embodiment of the ferrule manufacturing method according to the present invention. The ferrule manufacturing method shown in the figure comprises steps 100-104.

In the step (molding) 100, a ferrule material 1-1 having a shape as shown in FIG. 8 (a) is molded. Since the shape and molding method of the ferrule material 1-1 are the same as the conventional ones, detailed description thereof will be omitted.

In the step (end face rough grinding) 101, after the ferrule material is molded, both end faces 1-1 of the ferrule material 1-1 are formed.
Rough grinding is performed on a and 1-1b (see FIG. 8B).

Step (Outer Diameter Rough Grinding [Both Center Method]) 10
In FIG. 2, as shown in FIG. 8C, the outer diameter portion 1-1c of the ferrule material 1-1 is roughly ground, and the outer diameter of the ferrule material 1-1 and the eccentricity of the prepared hole 2-1 (ferrule material 1-
1) which was generated in the molding stage) is removed, and the outer diameter of the ferrule material 1-1 and the prepared hole 2-1 are made coaxial.

In this outer diameter rough grinding, the ferrule material 1-1 is supported at both centers. For both center support, the centers 6 and 7 are brought into contact with the prepared holes 2-1 from the both end surfaces 1-1a and 1-1b of the ferrule material 1-1, whereby the ferrule material 1-1 has both end surfaces 1-1a, It shall be supported from the 1-1b side.

In the step (inner diameter polishing) 103, the prepared hole 2-1 of the ferrule material 1-1 from which the eccentricity has been removed is polished (see FIG. 8D).

In this inner diameter polishing, a cylindrical holder 9 having a shape as shown in FIG. 9 is used as a polishing jig. One end side of the cylindrical holder 9 is formed as a material insertion port 900, the other end side of the cylindrical holder 9 is formed as a free abrasive grain insertion port 901, and the inside of the body of the cylindrical holder 9 is formed as a material setting part 902. The inner diameter of the material setting portion 902 is set slightly larger than the outer diameter of the eccentricity-removed ferrule material 1-1 in units of micro.

The ferrule material 1 from which the eccentricity has been removed from the material insertion opening 900 side of the tubular holder 9 to the material setting portion 902.
When the ferrule materials 1-1, 1-1, ... Are contacted in the cylindrical holder 9 to be positioned and fixed in a vertical column when the 1, 1-1, ... By inserting and mounting 903, it is pressed and fixed to the free abrasive grain insertion port 901 side.

That is, in step 103, when performing inner diameter polishing, a plurality of eccentricity-removed ferrule materials 1 are previously prepared.
-1, 1-1 ... are brought into contact with the inside of the cylindrical holder 9 and positioned and fixed in a column. After that, from the end face side of the cylindrical holder 9, the ferrule materials 1-1, 1-1 ... Prepared holes 2-1, 2-1 ...
Then, a polishing taper wire 12 and loose abrasive grains 10 are inserted. As a result, all of the prepared holes 2-1, 2-1 ... Are polished at the same time with the outer diameter of the ferrule material 1-1 as a processing reference. The tapered wire 12 is inserted through the loose abrasive grain insertion port 901.

In step 104 (end surface finishing grinding),
Usually, the end surface 1-1a is often required to have a convex spherical surface, and therefore the end surface 1-1a of the ferrule material 1-1 is processed into a convex spherical surface (predome grinding) or the like (see FIG. 8F).

In the ferrule manufacturing method of this embodiment, the eccentricity-removed ferrule material 1 is prepared at the time of polishing the prepared hole.
The positions 1, 1-1, ... Are fixed and fixed by a simple one-touch operation only by abutting on the cylindrical holder 9 instead of an adhesive agent. Therefore, the use of adhesive in the ferrule manufacturing process can be abolished, and the setup work that is time-consuming and difficult to unmanner, such as adhesive injection setting work and removal work, is omitted. This is suitable for shortening the time and fully automating the manufacturing process.

Further, according to this ferrule manufacturing method, since the positioning and fixing of the ferrule materials 1-1, 1-1, ... Are made by abutting against the inside of the cylindrical holder 9, the ferrule material is kept inside the cylindrical holder 9. Since the set state of 1-1, 1-1 ... does not collapse and the ferrule materials 1-1, 1-1 ... do not tilt and fall, the setting accuracy and the cylindrical holder 9 are well balanced. It is possible to polish the pilot holes 2-1, 2-1 ... Under good working conditions, and to process the parallelism and eccentricity of the pilot holes 2-1, 2-1 ... to the outer diameter of the ferrule material. The accuracy is improved, the high speed rotation of the cylindrical holder 9 is possible, and the working efficiency is also improved.

In particular, this ferrule manufacturing method is a wireless system in which the positioning and fixing of the ferrule raw materials 1-1, 1-1, ... simply contact the ferrule raw materials 1-1, 1-1, ... in the cylindrical holder 9. Therefore, even if the positioning and fixing using a wire as in the prior art has a poor setting accuracy, for example, the prepared hole 2-1 has a tapered nozzle shape, it can be set in parallel with the cylindrical holder 9 with good accuracy. ,
The processing accuracy can be improved.

In this ferrule manufacturing method, the outer diameter of the ferrule material 1-1 and the eccentricity of the pilot hole 2-1 are removed by grinding the outer diameter in advance before polishing the pilot hole 2-1. Since it is not necessary to newly provide a step for removing the eccentricity after polishing the prepared hole 2-1 as in the conventional case, the step can be simplified.

When it is necessary to suppress the eccentricity to an extremely small value, it is effective to perform the outer diameter finish grinding in order to correct the eccentricity deterioration amount due to the inner diameter polishing after the step 103 (inner diameter polishing). For such outer diameter finish grinding, the two center support method similar to the step 102 is suitable.

The means for pressing and fixing the ferrule raw materials 1-1, 1-1 ... to the free abrasive grain insertion opening 901 side is not limited to the insertion and mounting of the screw 903 into the raw material insertion opening 900, as shown in FIG. A part of the ferrule material 1-1 may be projected to the outside from the material insertion port 900, and the pressing plate 10 may be screwed to the cylindrical holder 9 from the protruding end side.
Although the cylindrical holder 9 shown in the figure is provided as a vertically divided two-piece type, such a two-piece type can also perform positioning and fixing by abutting the ferrule materials 1-1, 1-1.

The pressing and fixing means may be constituted by a claw 11 as shown in FIG. 11 instead of using a screw. In this case, the claw 11 is provided on the material insertion port 900 side of the cylindrical holder 9. , And ferrule material 1 due to spring force etc.
It is assumed that 1, 1-1, ... Can be pressed from the end face side to the free abrasive grain insertion port 901 side.

The cylindrical holder 9 may be provided with a plurality of vertical dividing grooves like a collet and can be opened and closed in the radial direction by utilizing the gaps between the grooves. It can be brought into contact with the ferrule material and its positioning and fixing can be performed.

FIG. 12 shows another embodiment of the ferrule manufacturing method according to the present invention. The ferrule manufacturing method shown in the figure comprises steps 100a to 105a, and then details of the steps 100a to 105a. Will be described with reference to FIG.

In the step (molding) 100a, a ferrule material 1-1 having a shape as shown in FIG. 8 (a) is molded. Since the shape and molding method of the ferrule material 1-1 are the same as the conventional ones, detailed description thereof will be omitted.

In the step (rough grinding of the end surface) 101, after the ferrule material is molded, both end surfaces 1-1 of the ferrule material 1-1 are formed.
Rough grinding is performed on a and 1-1b (see FIG. 8B). Since the rough grinding method is the same as the conventional one, its detailed description is omitted.

Process (Outer Diameter Rough Grinding [Both Center Method]) 10
In 2a, as shown in FIG. 8C, rough grinding is performed on the outer diameter portion 1-1c of the ferrule material. In such outer diameter rough grinding, the ferrule material 1-1 is supported at both centers. Both center supports 1 on both sides of the end face of ferrule material 1-1
Centers 6 and 7 are brought into contact with the prepared hole 2-1 from -1a and 1-1b, whereby the ferrule material 1-1 is brought into contact with both end surfaces 1-1.
It shall be supported from the a, 1-1b side.

That is, in the step 102a, from the viewpoint of making the outer diameter of the ferrule material 1-1 and the prepared hole 2-1 coaxial, the outside diameter of both center supports is previously prepared before polishing the prepared hole 2-1. Rough grinding is performed, and ferrule material 1-
The eccentricity and inclination of the outer diameter of 1 and the prepared hole 2-1 are removed.

In the step (inner diameter polishing) 103a, as shown in FIG.
As shown in (d), the prepared hole 2-1 is polished on the ferrule material 1-1 after the outer diameter rough grinding is completed. Such inner diameter polishing is performed on the basis of the outer diameter of the ferrule material 1-1, that is, while supporting the outer diameter portion 1-1c of the ferrule material 1-1.

Process (Outer Diameter Finish Grinding [Both Center Method]) 1
In 04a, as shown in FIG. 8 (e), the ferrule material 1-
The outer diameter portion 1-1c of No. 1 is ground and finished. In such an outer diameter grinding finish, the ferrule material 1-1 is supported at both centers. Since both center supports are the same as those in the above step 102a, detailed description thereof will be omitted.

In step 105a (end surface finishing grinding), processing (predome grinding) or the like is performed in which the end surface 1-1a of the ferrule material 1-1 is made into a convex spherical surface (see FIG. 8 (f)).

In the ferrule manufacturing method of this embodiment, the outer diameter of the ferrule material and the eccentricity and inclination of the pilot hole 2-1 are removed by grinding the outer diameter of the pilot hole 2-1 before polishing the pilot hole 2-1. . Therefore, when providing the outer diameter allowance of the ferrule material 1-1, it is sufficient to consider only the eccentricity and inclination of the molding error that occur in the molding step (process 100a) of the ferrule material 1-1. It is possible to minimize the number of ferrules 1-1
The number of molding materials can be reduced, and ferrules can be manufactured at low cost with few materials.

According to this ferrule manufacturing method, since the outer diameter machining allowance is reduced as described above, the time required for the outer diameter grinding can be reduced, and the ferrule manufacturing time can be shortened.

Further, in this ferrule manufacturing method, since all of the outer diameter grinding is performed by the double center method, it is difficult and unattended for a long time to wire-set the ferrule material in the wire centerless method. The present invention is suitable for automating the ferrule manufacturing process and improving the processing accuracy, since there is no setup work that is difficult to perform with high accuracy. In particular, it is most suitable for obtaining a desired processing accuracy for a pilot hole having a nozzle shape.

The end surface rough grinding in step 101a and the end surface finish grinding in step 105a may be performed before the outer diameter rough grinding (step 102a) or after the outer diameter finish grinding (step 104a). it can.

[0109]

According to the present invention, at least three protrusions are provided on the inner wall of the other end of the fiber insertion hole, and these protrusions are used as a center contact reference when the ferrule outer diameter is ground. For this reason, when the outer diameter of the ferrule is ground, the center jig comes into contact with the projecting portion of the contact reference instead of the hole entrance having an uneven contour after the injection molding, so that the contact state of the center jig is stable, The accuracy of outer diameter grinding is improved, and a highly accurate optical fiber connector can be obtained.

According to the present invention, the three-point contact between the center jig and the projecting portion can be surely obtained through the contact between the center jig and the projecting portion without any processing after the injection molding and before the outer diameter grinding. Since it is not necessary to finish the other end of the fiber insertion hole to a predetermined dimensional accuracy before grinding the outer diameter, the center hole processing for finishing can be omitted, and the ferrule manufacturing process is reduced accordingly. It is possible to simplify the manufacturing process of the fiber connector and reduce its manufacturing cost.

According to the present invention, the above-mentioned protrusion is also spherical. Therefore, even if the protruding portion is left as it is, the optical fiber element wire is not damaged by the protruding portion later, and secondary processing for preventing damage can be omitted. The manufacturing process can be simplified and the manufacturing cost can be reduced.

Further, in the present invention, the portion from the positioning portion to the entrance side of the fiber insertion hole is smoothly widened as a skirt widened portion. Therefore, during injection molding of the ferrule body, cavities (inner sinks) and burrs are less likely to occur in the fiber insertion hole, and the positioning part can be finished in the desired shape, improving the positioning and fixing accuracy of the optical fiber strand. In addition, it is possible to improve the reliability of the optical communication because it is possible to prevent the optical fiber strand from being damaged by the burr, which is suitable for performing the highly reliable optical communication. Also,
Secondary processing for preventing the damage can be omitted, and the optical fiber element wire can be inserted into the fiber insertion hole without performing secondary processing. Therefore, the ferrule manufacturing process can be simplified and manufactured. It is possible to reduce the time and the manufacturing cost.

According to this invention, only the inner side of the fiber insertion hole is formed as the positioning portion. For this reason, the finishing process for positioning and fixing is not required for the entire fiber insertion hole, but only for the positioning part, so that the finishing processing amount and processing time are reduced, and the ferrule manufacturing time and manufacturing cost are also reduced. Can be achieved.

According to the present invention, only the positioning portion of the fiber insertion hole is a fine hole. For this reason, a part of the fiber insertion hole is a fine hole rather than the whole, and the length of the fine hole is short, so that the bending of the fiber insertion hole becomes as small as possible during injection molding of the ferrule body. Therefore, it is possible to omit a process for correcting such a bent hole, and also in this respect, the ferrule manufacturing process can be simplified, the manufacturing time can be shortened, and the manufacturing cost can be reduced.

Further, according to the present invention, when the prepared hole is polished, the ferrule material from which the eccentricity has been removed is positioned and fixed by a simple one-touch operation only by abutting on the cylindrical holder, not by an adhesive. is there. For this reason, the use of adhesives in the ferrule manufacturing process is abolished, and as a result, it is possible to omit the time-consuming work of setting up the adhesives, which leads to a reduction in ferrule manufacturing time and full automation of the manufacturing process. It is suitable for constructing a fully automatic manufacturing system aimed at labor saving and unmanned operation.

According to the present invention, the positioning and fixing of the ferrule material is based on the contact with the inside of the cylindrical holder. For this reason, the set state of the ferrule material does not collapse in the tubular holder, the ferrule material does not tilt and fall, and the setting accuracy and the tubular holder are well balanced. The prepared hole can be polished, the processing accuracy is improved, and the cylindrical holder can be rotated at high speed, so that the processing efficiency is improved.

According to the present invention, the ferrule material is positioned and fixed by a wireless system in which the ferrule material is simply brought into contact with the inside of the cylindrical holder. For this reason, even if the positioning and fixing using wires as in the conventional case has poor setting accuracy, for example, even if the prepared hole has a tapered nozzle shape, it can be set in parallel with the cylindrical holder with high accuracy, and the processing accuracy is improved. Can be achieved.

According to the present invention, the outer diameter of the ferrule material and the eccentricity of the prepared hole are removed by grinding the outer diameter of the prepared hole before polishing the prepared hole. Therefore, firstly, it is not necessary to newly provide a step for removing the eccentricity after polishing the prepared hole as in the related art, and such a step can be omitted, so that the step can be simplified. Secondly, when the outer diameter allowance of the ferrule material is provided, it is only necessary to consider the eccentricity and inclination of the molding error that occur during the molding process of the ferrule material, so it is possible to minimize the outer diameter allowance. Therefore, it is possible to reduce the molding material of the ferrule material and the time required for the outer diameter grinding, and it is suitable to reduce the cost of this type of ferrule and the manufacturing time thereof.

According to the present invention, since all of the outer diameter grinding is performed by the double center method, unmanned operation such as wire setting work of the ferrule material in the wire centerless method is difficult and requires a long time, and is performed with high accuracy. It is possible to automate the ferrule manufacturing process and improve the processing accuracy without the difficult setup work.

[Brief description of the drawings]

FIG. 1 is a sectional view and a side view showing an embodiment of the present invention.

FIG. 2 is an explanatory view of a method for manufacturing the ferrule shown in FIG.

FIG. 3 is a sectional view and a side view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing an embodiment of a ferrule according to the present invention.

5 is an explanatory view of a method for manufacturing the ferrule shown in FIG.

FIG. 6 is a sectional view showing another embodiment of the ferrule according to the present invention.

FIG. 7 is an explanatory view showing an embodiment of a ferrule manufacturing method according to the present invention.

8 is a detailed explanatory view of the manufacturing process shown in FIG.

9 is a sectional view of a cylindrical holder used in the ferrule manufacturing method shown in FIG.

FIG. 10 is a sectional view showing another embodiment of the tubular holder.

FIG. 11 is a cross-sectional view showing another embodiment of the tubular holder.

FIG. 12 is an explanatory view showing another embodiment of the ferrule manufacturing method according to the present invention.

FIG. 13 is a sectional view of a conventional ferrule.

FIG. 14 is an explanatory view showing a conventional ferrule manufacturing method.

15 is a detailed explanatory view of the manufacturing process shown in FIG.

FIG. 16 is an explanatory view showing a conventional ferrule manufacturing method.

FIG. 17 is an explanatory view showing a conventional ferrule manufacturing method.

FIG. 18 is a sectional view of another conventional ferrule.

FIG. 19 is an explanatory view showing a conventional ferrule manufacturing method.

FIG. 20 is an explanatory view showing a conventional ferrule manufacturing method.

[Explanation of symbols]

 1 Ferrule main body 2 Fiber insertion hole 6, 7 Center jig 9 Cylindrical holder 11 Tapered wire 200 Holding hole 201 Expanding part 202 Positioning part 203 Hem spreading part 204 Curved part 1-1 Ferrule material 2-1 Under hole

 ─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 7-231725 (32) Priority date Hei 7 (1995) September 8 (33) Priority claim country Japan (JP)

Claims (8)

[Claims] 1. An optical fiber connector comprising a ferrule main body for centering and holding an end portion of an optical fiber strand, wherein the ferrule main body has a hole diameter at one end for holding an outer peripheral surface of the optical fiber strand. A fiber insertion hole formed of a holding hole, the other end side of which is in communication with the holding hole as an enlarged diameter portion having a diameter larger than that of the holding hole, and the inner diameter of the other end of the fiber insertion hole is the outer diameter of the ferrule body. An optical fiber connector, characterized in that a plurality of protrusions serving as a contact reference of a center jig used during grinding are formed. 2. The optical fiber connector according to claim 1, wherein the projection has a curved surface shape. 3. An optical fiber connector ferrule comprising a ferrule body having a fiber insertion hole for inserting an optical fiber, wherein the inner side of the fiber insertion hole is in close contact with the outer peripheral surface of the optical fiber. A ferrule for an optical fiber connector, characterized in that it is formed as a positioning portion for a narrow hole, and the inlet side of the fiber insertion hole is provided as a skirt spreading portion that spreads smoothly from the positioning portion. 4. An eccentricity between the outer diameter of the ferrule material and the pilot hole is removed by using a ferrule material having a cylindrical shape in which a pilot hole for inserting an optical fiber penetrates between the end faces and rough grinding the outer diameter of the ferrule material. After that, a plurality of eccentricity-removed ferrule materials are brought into contact with the cylindrical holder to position and fix them in a vertical column, and then loose abrasive grains are inserted into the prepared hole of the eccentricity-removed ferrule material from the end face side of the cylindrical holder. A method of manufacturing a ferrule for an optical fiber connector, characterized by polishing the prepared hole. 5. A cylindrical ferrule material, in which a prepared hole for inserting an optical fiber penetrates between end surfaces, is used, and a center jig is brought into contact with the prepared hole from both end surfaces of the ferrule material, whereby the ferrule material is formed. Roughly grinding the outer diameter of the ferrule material with both center supports that support both ends with the center jig, remove the eccentricity and inclination of the ferrule material outer diameter and the pilot hole, and then remove the ferrule material outer diameter. After polishing the prepared hole of the ferrule material, the center jig is brought into contact with the prepared hole from both sides of the end surface of the ferrule material, so that both center supports support the ferrule material from both end surfaces with the center jig. A method for manufacturing a ferrule for an optical fiber connector, which comprises performing outer diameter finish grinding of a ferrule material. 6. The method of manufacturing a ferrule for an optical fiber connector according to claim 5, wherein the end face rough grinding of the ferrule material is performed in advance before the outer diameter rough grinding. 7. The method of manufacturing a ferrule for an optical fiber connector according to claim 5, wherein the end surface finish grinding of the ferrule material is performed after the outer diameter finish grinding. 8. The method for producing a ferrule for an optical fiber connector according to claim 5, wherein the end face rough grinding and the end face finish grinding of the ferrule material are performed before the outer diameter rough grinding or after the outer diameter finish grinding. .