JP2995614B2 - Ferrule material molded body, method for degreasing / sintering the same, and method for manufacturing ferrule - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule raw material molded article for producing a ferrule of an optical connector, and a sintering of the molded article.

[0002]

2. Description of the Related Art In an optical connector used for connecting optical fibers in optical communication or the like, a ferrule for fixing an end of the optical fiber is incorporated. FIG. 11 is a schematic perspective view of a ferrule. FIG.
As shown in FIG. 1, the completed ferrule 11 is basically cylindrical and has an insertion hole 12 at the center for inserting an optical fiber and fixing it with an adhesive. For example, the length of the ferrule 11 is 10 mm, the outer diameter is 2.5 mm, and the diameter of the insertion hole 12 is about 125 μm.

[0003] The ferrule 11 is usually made of a ceramic such as zirconia. In the manufacture of the ferrule 11, first, a compound material composed of ceramic powder such as zirconia as a raw material and a binder material (a resin is used) is filled into a mold having a predetermined shape, and is heated at about 150 ° C. to form a ferrule material. Build your body. Next, in a process called degreasing, only the resin in the compound material is removed at about 420 ° C. Then, the ferrule material molded body is sintered at a high temperature of about 1500 ° C. to obtain a ferrule material sintered body, and finally, is polished to a predetermined size to obtain a ceramic ferrule 11. Hereinafter, sintering will be represented by contents including degreasing and sintering. Here, the compact shrinks by about 24% (linear shrinkage) during the sintering process.
The ferrule material molded body is formed to be larger than the final size of the ferrule 11 in consideration of its shrinkage ratio and polishing allowance. For example, in the example of the ferrule 11 described above, the ferrule material molded body has an outer diameter of 3.4 mm, and the diameter of the insertion hole 12 is 130 μm.

FIG. 12 is a perspective view showing a state in which a support base ferrule material molded body used for a conventional sintering operation is set.
In the conventional sintering operation of a molded body, as shown in FIG. 12, a support 14 made of a brick called a setter having a plurality of V-shaped grooves 13 on the upper surface is used, and a ferrule material molded body 15 is formed in each groove 13. Is placed in a sintering furnace to sinter the ferrule material compact 15.

Conventionally, the ferrule material compact 15 has been sintered in a state of being laid on the support 14, so that when the ferrule material compact 15 contracts during sintering, the support 1
There was a problem that the ferrule material molded body 15 was bent due to the frictional resistance of the contact surface with the ferrule material 4. As shown in FIG. 13 showing a schematic perspective view of a sintered ferrule material sintered body curved by sintering, the bending amount d measured at the end and the center of the insertion hole 12 of the sintered body 16 curved by sintering is Total length 10
It reaches 30 μm in mm.

For this reason, in order to obtain a ferrule 11 having predetermined dimensions and parallel insertion holes 12, the inner peripheral surface of the insertion hole 12 of the ferrule material sintered body 16 is polished by a relatively large amount and the bent portion is removed. There is a problem that it is necessary to cut off and a large number of man-hours are required for machining. Insertion hole 1
In order to finish the outer diameter of the sintered body 16 to a specified size around the center 2, there is a problem in that the outer diameter is increased in consideration of the working space. Furthermore, if the amount of bending is large,
There is also a problem that the hole after sintering is not processed and corrected, and a part of the hole remains after polishing and the shape of the opening of the insertion hole 12 of the optical fiber is not circular but irregular.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a ferrule material formed body which reduces the curvature generated when the ferrule material formed body is sintered, and a method for sintering the same.

[0008]

A ferrule material molded body according to the present invention which solves the above-mentioned problems has a substantially cylindrical shape having an insertion hole for an optical fiber, and is provided at one end with a hanging part. It is characterized in that the engaging portion is provided in a protruding manner.

Further, according to the method for sintering a ferrule material molded body according to the present invention, a ferrule material molded body having a substantially cylindrical shape having an insertion hole for an optical fiber is oriented such that the axis of the insertion hole is oriented vertically. And sintering it in a suspended state. In the method of sintering a ferrule material molded body, preferably, the ferrule material molded body has an engaging portion for hanging at one end thereof, and the supporting portion is placed on a support base to support the ferrule material molded body. The ferrule material molded body is suspended vertically on a table.

The method of manufacturing a ferrule according to the present invention is directed to a ferrule material having a substantially cylindrical shape having an insertion hole for an optical fiber and having a hanging engaging portion protruding at one end. The method includes a step of sintering the molded body in a state of being suspended so that the axis of the insertion hole is oriented in a vertical direction, and a step of removing the engaging portion after sintering.

Further, the ferrule material sintered body according to the present invention has a substantially cylindrical shape having an insertion hole for an optical fiber, and a ferrule material having a hanging engaging portion protruding at one end. The molded body is formed by sintering in a state of being suspended so that the insertion holes face in the vertical direction.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a ferrule material molded body according to one embodiment of the present invention. As shown in FIG. 1, the ferrule material molded body 21 is formed by integrally molding a main body part 22 having a substantially cylindrical shape and an engaging part 23 protruding from one end of the main body part 22. , At 150 ° C. The raw material is, for example, yttria-added partially stabilized zirconia (ZrO ₂ .Y ₂ O ₃ (Y ₂ O
₃ : 3 mol%))) is used.

The engaging portion 23 has a generally disk shape having an outer diameter larger than the outer diameter of the main body portion 22, and has a concave portion 24 on its end face.
Are formed. For example, the outer diameter of the main body 22 is 3.4.
mm, the length excluding the engaging portion 23 is 16 mm, and the outer diameter of the engaging portion 23 is 5 to 7 mm. An insertion hole 25 for an optical fiber is opened in the center of the ferrule material molded body 21 along the length direction. The opening of the insertion hole 25 on the side of the engaging portion 23 is a tapered portion 26 whose diameter gradually increases in a tapered shape so that the optical fiber can be easily inserted.

The ferrule material molded body 21 is about 150
Sintered at a high temperature of 0 ° C. to form a sintered body. FIG. 2 is a perspective view showing a state in which a ferrule material molded body is set on a support used for this sintering operation, and FIG. 3 is a sectional view taken along line AA of FIG.
As shown in FIGS. 2 and 3, the ferrule material molded body 21 is sintered in a state where the ferrule material molded body 21 is suspended using the engaging portion 23 so that the axis of the optical fiber insertion hole 25 is oriented in the vertical direction. Is done. In other words, on the brick support 27,
A plurality of accommodation holes 28 having a circular cross section into which the main body portion 22 of the ferrule material molded body 21 is inserted are formed, and an upper portion of the accommodation hole 28 is an enlarged support hole into which the engaging portion 23 of the ferrule material molded body 21 is fitted. 29 are formed. Housing hole 28
Is set smaller than the outer diameter of the engaging portion 23 of the ferrule material molded body 21, and when the ferrule material molded body 21 is inserted into the accommodation hole 28, the engaging portion 23 contacts the end face of the accommodation hole 28 and The part 22 is suspended in the accommodation hole 28.

The difference between the diameter of the support hole 29 and the diameter of the engaging portion 23 is set to be smaller than the difference between the diameter of the housing hole 28 and the diameter of the main body portion 22. Even when the engaging portion 23 comes into contact with the peripheral wall surface of the support hole 29 in a state of being fitted in the main body portion 22, the main body portion 22 does not come into contact with the peripheral wall surface of the accommodation hole 28.

By inserting the ferrule material molded body 21 into the accommodating hole 28 of the support 27, the ferrule material molded body 21 is suspended so that the axis of the optical fiber insertion hole 25 is oriented in the vertical direction. Sintering is performed. In this state, the main body 22 of the ferrule material molded body 21 is not in contact with the surrounding wall surface, and has a shape that is always pulled in the vertical direction by its own weight, so that the ferrule material molded body 21 bends when the sintering shrinks. Can be effectively prevented.

As shown in FIG. 4, the support base 27 is not provided with the support hole 29 but only the accommodation hole 28 is provided, and the engaging portion 23 of the ferrule material molded body 21 is placed on the upper surface of the support base 27. Alternatively, the ferrule material molded body 21 may be supported. FIG. 5 is a graph comparing the case of the present invention sintered as described above with the case of sintering by the conventional method. As shown in FIG. 5, the bending amount d is conventionally 2
While the frequency of 5 to 30 μm was the highest, the bending amount d was reduced to 5 to 10 μm according to the present invention,
It can be seen that the frequency of 5 μm is the highest among them.

FIG. 6 is a partial perspective view of a half body according to another example of the support base, and FIG. 7 is a plan view showing a state where the support base is formed by abutting the half bodies. As shown in FIGS. 6 and 7, the support base 31 is formed by abutting two half bodies 33 having a plurality of vertical grooves 32 having a V-shaped cross section on an edge surface thereof. 34. FIG.
As shown in FIG.
Into the receiving hole 34, and the engaging portion 23 is
, The ferrule material molded body 21 is supported in a suspended state such that the axis of the optical fiber insertion hole 25 is oriented in the vertical direction. Although the accommodation hole 28 is formed in the support 27 shown in FIG. 2, the accommodation hole 34 is formed by abutting the vertical grooves 32 as shown in FIG. Manufacturing can be facilitated.

Here, when the main body 22 of the ferrule material molded body 21 is individually put into the accommodation holes 28 and 34 and sintered, a uniform heating environment can be obtained for each ferrule material molded body 21. This has the effect of preventing the occurrence of variations in the sintering results.

FIG. 8 is a plan view of still another example of the support base. The support base 41 shown in FIG. 8 is formed by arranging two members 42 having flat edge surfaces at predetermined intervals, and the main body 22 of the ferrule material molded body 21 is disposed between the two members 42. By inserting and placing the engaging portion 23 on the upper surface of both members 42, the ferrule material molded body 21 is supported in a suspended state in the vertical direction. Since there is no need to form holes or grooves in the support table 41, manufacture is easier.

FIGS. 9 and 10 are perspective views showing other examples of the ferrule material molded body. The shape of the ferrule material molded body is not limited to the above-described one. For example, as shown in FIG. 9, the shape of the engaging portion 23 in which the concave portion 24 is omitted, or as shown in FIG. It may have a square rod shape, or may have a conical shape. In short, the engaging portion 23 may be any member as long as it protrudes laterally from the main body 22 in order to suspend the ferrule material molded body 21.

In this manner, the ferrule material molded body 21
Is sintered into a ferrule material sintered body, and then the ferrule material sintered body is subjected to required polishing to obtain a ferrule. Here, since the bending caused during sintering can be reduced by suspending and sintering, the polishing allowance can be reduced, and the polishing operation is facilitated and the number of processing steps can be reduced. Further, since the polishing allowance for removing the bending can be small, the size of the ferrule material molded body 21 before sintering can be reduced as compared with the conventional case. After sintering, the engaging portion 23 is removed and polished to obtain a ferrule.

[0023]

As described above, according to the present invention, the ferrule material molded body is sintered in a state of being suspended so that the axis of the optical fiber insertion hole is oriented in the vertical direction. The ferrule material molded body is prevented from being bent at the time of shrinkage, and a sintered body with less curvature can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a ferrule material molded body according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which a ferrule material molded body according to the present invention is set on a support used for a sintering operation.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a cross-sectional view showing a state where a ferrule material molded body according to the present invention is set on another support base.

FIG. 5 is a graph comparing the case of sintering according to the conventional method with the case of the present invention.

FIG. 6 is a partial perspective view of a half body according to another example of the support base.

FIG. 7 is a plan view of a state in which a support base is formed by abutting the half bodies of FIG. 6;

FIG. 8 is a plan view of still another example of the support base.

FIG. 9 is a perspective view illustrating another example of a molded ferrule material.

FIG. 10 is a perspective view illustrating another example of a molded ferrule material.

FIG. 11 is a schematic perspective view of a ferrule.

FIG. 12 is a perspective view of a state in which a support base ferrule material molded body used for a conventional sintering operation is set.

FIG. 13 is a schematic perspective view of a ferrule material sintered body curved by sintering.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Ferrule 21 Ferrule raw material molded body 22 Main part 23 Engagement part 25 Optical fiber insertion hole 26 Taper part 27, 31, 41 Support base 28, 34 Housing hole 29 Support hole

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Setsuo Tokaibayashi 6-31-1, Kameido, Koto-ku, Tokyo Inside Nastec Industrial Co., Ltd. (56) References JP-A-59-62105 (JP, A) 2-240203 (JP, A) JP-A-5-134141 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 6/36 C04B 35/64

Claims (5)

(57) [Claims] 1. A ferrule material molded body having an insertion hole for an optical fiber, having a substantially cylindrical shape, and having an engaging portion projecting from one end. 2. A ferrule material molded article having an insertion hole for an optical fiber and having a substantially cylindrical shape is sintered in a state of being suspended so that the axis of the insertion hole is oriented in the vertical direction. Method for sintering a ferrule material molded body. 3. The ferrule material molded body has a hanging engaging portion protruding at one end thereof, and the ferrule material molded product is vertically mounted on the supporting stand by mounting the engaging portion on the supporting stand. 3. The method for sintering a ferrule material molded body according to claim 2, wherein the sintering is performed. 4. A ferrule material molded body having a substantially cylindrical shape having an insertion hole for an optical fiber and having an engaging portion for hanging protruding at one end thereof, wherein the axis of the insertion hole is vertical. The method for producing a ferrule according to claim 4, further comprising a step of sintering in a state of being suspended so as to face in a direction, and a step of removing the engaging portion after sintering. 5. A ferrule material molded body having a substantially cylindrical shape having an insertion hole for an optical fiber and having an engagement portion for hanging at one end protruding, the insertion hole being vertically extended. A ferrule material sintered body that is sintered in a suspended state.