JP3302079B2 - Stepped pin and method of manufacturing ferrule using 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 method of manufacturing a ferrule, which is a main component of an optical fiber connector, and to a method of manufacturing a stepped pin used for manufacturing a mold.

[0002]

2. Description of the Related Art Conventionally, ferrule manufacturing methods include:
Extrusion and powder injection molding methods are used. FIG.
FIG. 3 is a view schematically showing an outline of a ferrule manufacturing process by an extrusion method.

[0003] In FIG. 7, a diameter 2 as shown in FIG.
An insulative (for example, using zirconia) rod material 14 having a through hole 1 with a diameter of 80 μm to 90 μm at the center of a 5 mm cylindrical shape is manufactured by an extrusion method, and then, as shown in FIG. Slice to .5mm. Then, as post-processing of the sliced ferrule 3, in order to expand the diameter of the through hole 1 to 120 μm to 130 μm,
(C) As shown in FIG.
After performing hole polishing using, as shown in (d),
To facilitate the passage of the fiber, all of the through holes 1 are manufactured by machining, such as forming a conical concave (tapered) portion 2 at one end of the through hole 1 with a diamond tool 16.

On the other hand, in the powder injection molding method, first, as a means for forming a mold for previously forming a through hole 1 and a conical concave (tapered) portion 2 in order to simplify post-processing of the zirconia ferrule. , Make a stepped pin. FIG. 8 is a view schematically showing a manufacturing process of a conventional stepped pin. In FIG. 8, carbide or tungsten as shown in FIG.
A bar 17 made of a metal such as a cobalt alloy is cut by a lathe or a grinder to form a stepped pin including a large-diameter portion 12, a conical projection 13 and a small-diameter portion 21 as shown in FIG. To manufacture. Next, a mold is made using the stepped pin manufactured as described above, and powder injection molding is performed using the mold to manufacture a ferrule.

[0005]

However, according to the conventional manufacturing method, according to the extrusion method, the ferrule having the through hole formed at the center is further subjected to polishing, grinding or the like to further reduce the ferrule. The process of widening and forming a conical recess at one end of the through hole is performed by machining, so the ferrule finish takes a lot of time and becomes a costly part. there were.

[0006] In addition, a stepped pin having a machined finish used for making a mold for powder injection molding may be machined straight when the diameter of the small diameter portion is 0.2 mm or less and the length is 5 mm or more. Difficult, diameter tolerance is ± 2
There was a problem that it could not be made within μm, and that the surface roughness after processing became rough, and the variation in accuracy became large.

Further, as for the material of the stepped pin, a material having high rigidity and toughness such as carbide or a tungsten-cobalt alloy has a problem that it is easily broken. Therefore, it takes time and effort to process the stepped pin, and since it becomes very expensive and a high-precision stepped pin cannot be obtained, the variation of the through hole formed in the center of the injection molded ferrule is large, In addition, there is a problem that an accurate finish cannot be obtained even if polishing and grinding are performed in a later process because of a rough finish inside the through hole.

The optical fiber connector cannot be used because the transmission performance is reduced even with a small error, so that a ferrule, which is a main component thereof, requires extremely high processing accuracy. The present invention has been made to solve the above problems, and an object of the present invention is to use a high-precision and highly tough metal wire rod that is thinned by an extrusion method for a small diameter portion, An object of the present invention is to provide a method of manufacturing a stepped pin having excellent surface smoothness by forming a large diameter portion and a projection on the wire by plating.

It is another object of the present invention to provide a method of manufacturing a stepped pin in which a final step of coating a ceramic thin film on the surface of the stepped pin is added. It is another object of the present invention to provide a technique capable of manufacturing a plurality of stepped pins at the same time.

Another object of the present invention is to manufacture a female mold using a stepped pin and manufacture ferrules having the same shape and the same dimensions by injection molding. The above and other objects and novel features of the present invention will become apparent from the description of the present invention and the accompanying drawings.

[0011]

In order to achieve the above object, a method of manufacturing a stepped pin according to the present invention comprises a columnar insulating material having a through hole at the center and a conical recess at one end. After inserting a metal straight pin into the through hole of the member, applying an insulating material to one end of the straight pin, and fixing a plating jig to the other end of the straight pin while maintaining electrical conduction. A step of applying an insulating material to a portion where the plating jig is immersed in a plating solution, and forming a large-diameter portion and a projection by building up by plating on a non-insulating portion of the straight pin, A step of cutting the plating jig from the large-diameter portion, and a step of extracting the cylindrical insulating member from the straight pin to form a stepped pin.

Further, a step of coating the surface of the stepped pin with a ceramic thin film is added to the last step of the stepped pin manufacturing method. Another method of manufacturing a stepped pin according to the present invention includes a plurality of cylindrical insulating members having a through hole at the center and a conical concave portion at one end, and a metal having a through hole in each of the insulating members. After inserting into the straight pin of
A step of applying an insulating material to a part of the straight pin and the surface of the insulating member without the concave portion, and fixing a plating jig to the tip of the straight pin while maintaining electrical continuity, and the plating jig is A step of applying an insulating material to a part immersed in a plating solution, a step of forming a large-diameter part and a projection by building up by plating on a non-insulating part of the straight pin, and starting from an end of the plating jig. The method includes a step of cutting the tip of the straight pin and a step of forming the stepped pin by extracting the plurality of insulating members from the straight pin.

A method of manufacturing a ferrule according to the present invention is characterized in that a female mold is manufactured using the stepped pin manufactured by the above manufacturing method, and a ferrule member is manufactured by injection molding using the female mold. And

[0014]

According to the above-mentioned means, the through-hole and the conical recess provided at the center of the cylinder are finished with high precision by machining such as grinding and grinding in advance. For example, a zirconia ferrule mold is used as a mold for manufacturing a stepped pin. A straight pin such as a nickel-cobalt (Ni-Co) wire or a piano wire is inserted into the zirconia ferrule-type through-hole and positioned, and a straight pin portion on the conical concave side of the zirconia ferrule-type member is positioned. A stepped pin having a conical projection can be obtained by forming a metal overlay by electroplating.

Further, the durability of the stepped pin can be increased by adding a step of coating the surface of the stepped pin with a thin ceramic film. Also, a plurality of insulating members can be inserted into the straight pins and plated, and a plurality of stepped pins can be manufactured at the same time.

Further, a female mold is manufactured using the stepped pins manufactured as described above, and a large number of zirconia ferrules having the same shape and the same dimensions can be manufactured by injection molding.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted. (Embodiment 1) FIG. 1 is a diagram schematically showing a step of manufacturing a stepped pin according to Embodiment 1 of the present invention. As shown in FIG. 1, the method of manufacturing the stepped pin according to the first embodiment is as follows. A zirconia rod is extruded in advance, and processed into a length of 10.5 mm and a diameter of 2.5 mm by machining such as grinding and grinding. After finishing, the center of cylindrical zirconia member 3 has a diameter of 1
26 μm through hole 1 and conical recess 2 provided at one end thereof
With high precision.

Next, as shown in FIG. 2B, for example, a nickel-cobalt (N
The straight pin 4 using an i-Co) wire or a piano wire is inserted and positioned. Next, as shown in (c), an insulating coating agent 5 is applied to the portion of the straight pin 4 protruding on the opposite side of the conical recess 2 of the zirconia member 3 to prevent deposition of a plating film.

Next, as shown in (d), the tip of the straight pin 4 projecting in the direction of the conical concave portion 2 of the zirconia member 3 is soldered to establish electrical conduction with the plating jig 6. Perform attachment 7 and fix. Subsequently, as shown in (e), an insulating seal 8 is wound around a part of the plating jig 6 immersed in the plating solution to prevent the deposition of the plating film.

Next, as shown in FIG.
The plating jig 6 is set as the cathode 11 at the center of the plating tank 10 in which is disposed, and a sulfamic acid-based nickel plating is performed. This plating is called an electroforming method. As shown in (g), the diameter of the large diameter portion is 1500 μm
The large diameter portion 12 and the conical projection 13 are formed on the straight pin 4 until the plating is completed. Next, the portion of the straight pin 4 covered with the insulating seal 8 is cut off from the plating jig 6, and then the insulating coating agent 5 is peeled off and the zirconia member 3 is removed. A stepped pin having a conical projection 13 and a large diameter portion 12 on the pin 4 was obtained.

(Embodiment 2) FIG. 2 is a view schematically showing an outline of a manufacturing process of a stepped pin according to Embodiment 2 of the present invention.
As shown in FIG. 2, the method of manufacturing the stepped pin according to the second embodiment uses a diameter of 2.5 mm and a length of 10.5 as shown in FIG.
A through hole 1 having a diameter of 130 μm was formed at the center of a cylinder 19 of an insulating member having a thickness of 1 mm, and a U-shaped concave portion 18 was formed at one end thereof. After inserting and positioning a straight pin 4 using a wire material such as a piano wire having a diameter of 129 μm and a length of 50 mm shown in FIG. 2B, metal overlaying is performed by the same process as in Example 1 thereafter, as shown in FIG. A stepped pin having a U-shaped projection 20 and a large diameter portion 12 on the straight pin 4 was obtained.

Regarding the shape of the stepped pin, various projection shapes can be obtained by variously changing the shape of a groove provided at one end of an insulating member used as a metal overlay plating mold according to various uses. Further, in addition to the above examples, an eccentric stepped pin in which the center of the straight pin is shifted from the large-diameter straight portion can be easily manufactured.

(Embodiment 3) FIG. 3 is a diagram schematically showing a process of simultaneously manufacturing a plurality of stepped pins according to Embodiment 3 of the present invention. As shown in FIG. 3A, the method of manufacturing a plurality of stepped pins according to the third embodiment uses a diameter of 125 μm.
m, three zirconia members 3 to be used as a mold for metal overlay plating are inserted into a straight pin 4 using a wire such as a piano wire having a length of 150 mm, and are positioned at equal intervals, as shown in FIG. Then, an insulating coating agent 5 is applied to the unnecessary portions of the straight pins 4 protruding from the conical concave portions 2 of the zirconia members 3 on the opposite sides thereof, and then the zirconia members 3 are coated as shown in FIG. The tip of the straight pin 4 protruding in the direction of the conical recess 2 was soldered 7 for electrical conduction to the plating jig 6. Subsequently, as shown in (d), an insulating seal 8 is wrapped around a part of the plating jig 6 immersed in a plating solution to prevent the plating film from depositing, and then on both sides as shown in (e). A plating jig 6 is set as a cathode 11 at the center of a plating tank 10 in which an anode plate 9 is arranged, and nickel plating of sulfamic acid is performed.

This plating is called an electroforming method. Each zirconia member 3 as shown in (f)
Of the conical concave portion 2 and the large-diameter portion 1
In order to form No. 2, after the metal meat was piled up until the diameter of the large diameter portion became 1600 μm, as shown in (g), the portion covered with the insulating seal 8 from the plating jig 6 was straightened. The pins 4 are cut off, and the ends of the large-diameter portions 12 formed by metal overlay plating are cut into single pieces. Subsequently, the insulating coating agent 5 is peeled off and the zirconia member 3 is removed.

Through the above steps, a plurality of stepped pins having a conical projection 13 and a large-diameter portion 12 on the straight pin 4 as shown in (h) were obtained. According to the third embodiment, a large number of stepped pins can be obtained in one process, and the efficiency is high. As described above, the accuracy of the stepped pin obtained according to Examples 1 to 3 is such that the straightness of the straight pin portion is 17 mm in length and the tolerance is ± 4 μm from the integrated stepped pin obtained by conventional machining. ± 1 at 20mm
μm, and the diameter tolerance improved from ± 3 μm to ± 1 μm.

Further, since the surface roughness of the straight pin and the projection formed by the metal overlaying on the straight pin portion is finished from the conventional 2 μmRmax to 0.5 μmRmax, the stepped pin is used as a mold by powder injection molding. The through hole of the zirconia member to be formed and the conical recess formed at one end thereof can be finished with high accuracy.

Another advantage is that the use of a tough material such as a nickel-cobalt (Ni-Co) wire or a piano wire as a straight pin allows the use of a straight pin.
The number of shots of powder injection molding can be increased from the conventional 2 times / shot to 500 times / shot, and the productivity can be improved.

As a final step in Examples 1 to 3 described above, the surface of the completed stepped pin was coated with a ceramic thin film to a thickness of 0.5 to 1.5 μm by ion plating. As shown in FIG. 4, a test was conducted to see how the durability of the stepped pin was increased as a result of coating the ceramic thin film.

In FIG. 4, the stepped pin is set on the fixed side 22 of the injection mold and is inserted into a hole 24 formed on the movable side 23 of the mold by clamping. A conical chamfer 25 is formed on the parting surface of the hole 24 so that the small diameter portion 21 of the stepped pin can be easily inserted into the hole 24. In actual mold clamping, the small diameter portion 21 collides with the slope of the conical chamfered portion 25 and slides into the hole 24. If the sliding resistance at this time is strong, the small diameter portion 21 is curved, and the force concentrates on the boundary between the small diameter portion 21 and the large diameter portion 12, and the small diameter portion 21 is broken.

With the stepped pin of the present invention as shown in FIG. 1 (h), the rigidity of the small diameter portion 21 is high, and the sliding resistance between the inclined surface of the chamfered portion 25 on the cone and the tip of the small diameter portion 21 is reduced. Since the small-diameter portion 21 does not bend in opposition, it does not peel off from the interface between the small-diameter portion 21 and the large-diameter portion 12 formed by electroforming.

Further, since the large diameter portion 12 formed by electroforming is also covered with the ceramic coating layer 26, a remarkable improvement in durability against abrasion was recognized. Table 1 shows the results of testing the thickness, durability (breaking / peeling) of the small diameter portion 21 and wear resistance of the large diameter portion 12 when aluminum nitride AlN is used as the ceramic coating layer 26 of the present invention.

Here, the diameter of the small diameter portion is 50 μm to 20 μm.
It was evaluated at 0 μm. The lower limit diameter was set to a value that could be practically obtained with this type of material. The maximum diameter is 20 for this type of material.
This is because when the thickness is 0 μm or more, the straightness of the small diameter portion 21 can be obtained even in the integrated processing. The lower limit of the thickness of the ceramic coating layer 26 is 1.5 μm at which the effect of preventing the small-diameter portion 21 from bending is obtained, and the upper limit is 1.5 μm which is considered to be practical for forming the ceramic coating layer 26. Since the generated stress varies depending on the formation conditions of 26, the thickness can be further increased in a range where peeling or the like does not occur. Table 2 shows the results of testing the thickness, durability (break / peel) of the small diameter portion, and wear resistance of the large diameter portion 12 when titanium nitride TiN is used as the ceramic coating layer 26.

(Embodiment 4) The method of manufacturing a zirconia ferrule of Embodiment 4 uses a high-precision pin with the same step manufactured by any one of the manufacturing methods of Embodiments 1, 2, and 3. Then, a female mold is manufactured, and a zirconia ferrule is manufactured by injection molding using the female mold. According to this method of manufacturing a zirconia ferrule, since a female mold is manufactured using the same high-precision stepped pin, it is possible to manufacture a large number of zirconia ferrules having the same shape and the same dimensions by using the same high-precision stepped pin. it can.

FIG. 5 is a partially cutaway perspective view showing the configuration of a connector to which the zirconia ferrule according to the present invention is applied and its adapter, and FIG. 6 is a sectional view taken on line AA of FIG.
It is the principal part cross-section enlarged view cut | disconnected by arrow. 5 and 6, 71 is an optical fiber, 72 is an optical fiber core, 73 is a ferrule, 74 is a mounting screw, 75 is a connector, and 76 is an adapter.

As shown in FIGS. 5 and 6, a zirconia ferrule having the same shape and the same dimensions manufactured according to the fourth embodiment is used as the ferrule 73.
Since a plurality of identical connection portions of the same system of optical fiber transmission lines can be obtained, the same transmission characteristics can be maintained in any part of the optical fiber transmission lines. This makes it easy to design and manufacture a long optical transmission line.

Although the present invention has been described in detail with reference to the embodiments, it goes without saying that various changes can be made without departing from the scope of the invention.

[0037]

As described above, according to the method of manufacturing the stepped pin according to the present invention, the small diameter portion is formed by the metal wire such as the piano wire which is thinned by the extrusion, so that the toughness is improved. High and high dimensional accuracy. In addition, since the large diameter portion and the protrusion are formed by electroforming, the surface smoothness is excellent, the post-process for ferrule production is simplified, and the step is ideal for making a mold for ferrule production. A pin is obtained.

Further, since the step of coating the surface of the stepped pin with a ceramic thin film is provided, the rigidity of the stepped pin is increased, and the portion which is built up by plating does not peel off from the straight pin. Further, since the stepped pin manufactured by the manufacturing method according to the present invention has excellent durability, a large number of molds for manufacturing ferrules can be made with the same stepped pin. In other words, since ferrules having the same shape and the same dimensions can be manufactured in large quantities, even a part for optical communication having a severe tolerance has very few defective parts,
High production efficiency can be maintained.

Further, since a plurality of identical connecting parts of the same system of optical fiber transmission lines can be obtained, the same transmission characteristics can be maintained in any part of the optical fiber transmission lines.
This makes it easy to design and manufacture a long optical transmission line.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a manufacturing process of a stepped pin according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating an outline of a manufacturing process of a stepped pin according to a second embodiment of the present invention.

FIG. 3 is a view schematically showing a step of simultaneously manufacturing a plurality of stepped pins according to a third embodiment of the present invention.

FIG. 4 is a view illustrating a durability test of a stepped pin manufactured according to the present invention.

FIG. 5 is a partially cutaway perspective view showing the configuration of a connector to which the zirconia ferrule according to the present invention is applied and an adapter thereof.

FIG. 6 is an enlarged cross-sectional view of a main part taken along line AA shown in FIG. 7;

FIG. 7 is a view schematically showing an outline of a manufacturing process of a zirconia ferrule by a conventional extrusion processing method.

FIG. 8 is a diagram schematically showing a manufacturing process of a conventional stepped pin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Through-hole 2 Conical concave part 3 Zirconia member 4 Straight pin 5 Insulating coating agent 6 Plating jig 7 Soldering 8 Insulating seal 9 Anode plate 10 Plating tank 11 Cathode 12 Large diameter part 13 Conical projection 14 Insulation Bar material 15 Wire 16 Diamond tool 17 Metal bar material 18 U-shaped recess 19 Insulating member 20 U-shaped projection 21 Small diameter portion 22 Mold fixed side 23 Mold movable side 24 Hole 25 Chamfered portion 26 Ceramic coating layer 71 Optical fiber 72 Optical fiber core wire 73 Ferrule 74 Mounting screw 75 Connector 76 Adapter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-235170 (JP, A) JP-A-2-228055 (JP, A) JP-A-4-214659 (JP, A) JP-A-56- 295 (JP, A) JP-A-4-206487 (JP, A) JP-A-63-129992 (JP, A) JP-A-1-105907 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/36-6/40 H01L 23/50 H01R 43/16

Claims (4)

(57) [Claims] 1. A metal straight pin is inserted into the through hole of a cylindrical insulating member having a through hole at the center and a conical recess at one end . Opposite to the conical recess of the cylindrical insulating member
A step of applying an insulating material to a portion protruding to the side, fixing a plating jig to the other end of the straight pin while maintaining electrical continuity, and insulating the portion where the plating jig is immersed in a plating solution. A step of applying a material, a step of forming a large-diameter portion and a projection by overlaying by plating on a non-insulating portion of the straight pin, a step of cutting the plating jig from the large-diameter portion, and A step of forming the stepped pin by extracting the columnar insulating member from the straight pin. 2. A metal straight pin is inserted into the through hole of a cylindrical insulating member having a through hole at the center and a conical recess at one end . Opposite to the conical recess of the cylindrical insulating member
A step of applying an insulating material to a portion protruding to the side, fixing a plating jig to the other end of the straight pin while maintaining electrical continuity, and insulating the portion where the plating jig is immersed in a plating solution. A step of applying a material, a step of forming a large-diameter portion and a projection by building up a non-insulating portion of the straight pin by plating, a step of cutting the plating jig from the large-diameter portion , A method for manufacturing a stepped pin, comprising: a step of forming the stepped pin by extracting the cylindrical insulating member from the pin; and a step of coating a ceramic thin film on a surface of the stepped pin. 3. Inserting a plurality of cylindrical insulating members having a through hole at the center and having a conical recess at one end into a metal straight pin into a through hole of each insulating member; after positioning substantially at equal intervals, wherein the step of subjecting the coating an insulating material on a part of the recess free surface of the insulating member and the straight pin, the plating jig to the distal end of the straight pin maintains the electrical conduction A step of applying an insulating material to a portion where the plating jig is fixed and immersed in a plating solution, a step of forming a large-diameter portion and a projection by building up by plating on a non-insulating portion of the straight pin, A step of cutting a tip of the straight pin from an end of the plating jig, and a step of forming a stepped pin by extracting the plurality of insulating members from the straight pin. Manufacturing method . 4. A ferrule according to claim 1, wherein the stepped pin manufactured by the process according to claim 1 is a male mold, and the ferrule is manufactured by injection molding using the male mold. Production method.