JP2015067531A - Support structure for glass base material, support pin, and method of manufacturing glass base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support structure for a glass base material that can prevent a support pin from being ruptured during manufacture of the glass base material, the support pin, and a method of manufacturing the glass base material.SOLUTION: There is provided a support structure for glass base material that supports a support rod 1 for starting base material with a support pin 10 by inserting the support pin 10 into a lock hole 1c formed in the support rod 1 for starting base material, rotated on a perpendicular axis during manufacture of a glass base material, in a direction orthogonal to the axial direction. A center part 11a of the support pin 10 has an outer diameter substantially equal to an inner diameter of the lock hole 1c within a range in which the support pin 10 can be inserted into the lock hole 1c, the support pin 10 has, on an end side relative to the center part 11a, a large-diameter part 11b (or a nut part 12) having a larger outer diameter than the center part 11b, and at least a part of the large-diameter part 11b (or the nut part 12) is in contact with the support rod 1 for starting base material.

Description

  The present invention relates to a glass base material support structure, a support pin, and a glass base material manufacturing method.

  For example, a glass base material for an optical fiber is a starting base that rotates around a vertical axis supported by a hanging rod on the gripping mechanism side by generating glass fine particles by ejecting a gas containing glass raw material gas and combustion gas from a burner. It is manufactured by depositing glass fine particles on a material, further subjecting it to dehydration treatment and sintering treatment to make it transparent and vitrified. The suspension rod and the starting base material support rod are connected to each other by inserting a support pin through a locking hole formed in the upper end portion of the support rod in a direction orthogonal to the axial direction (for example, Patent Document 1). To 5).

Japanese Patent Laid-Open No. 6-1507048 JP 2012-66972 A JP-A-5-147967 JP-A-5-193957 JP-A-2-160636

  As described above, in glass base material manufacturing and the like, the support pin is inserted into the locking hole formed in the direction orthogonal to the axial direction at the end of the support rod, thereby supporting the suspension rod on the gripping mechanism side. The support rod is supported by connecting the rod.

However, due to the recent increase in the size of the glass base material, the conventional support pins have insufficient load resistance, and the support pins may break. Further, although the support pin is used repeatedly, in order to prevent breakage during use, it is necessary to reduce the number of uses and frequently replace it with a new one. For this reason, many new support pins are held as auxiliary materials, which are consumed quickly, and the auxiliary material costs increase.
In order to suppress breakage of the support pins, measures such as changing the glass base material to a special shape or remodeling the support tool to a special shape can be considered, but the scope of modification on the target equipment side This increases the cost of capital investment and the like.

  Accordingly, an object of the present invention is to provide a glass base material support structure, a support pin, and a glass base material manufacturing method capable of suppressing breakage of the support pin during glass base material manufacturing while using conventional equipment and members as much as possible. Is to provide.

The glass base material support structure capable of solving the above problems is supported by a locking hole formed in a direction orthogonal to the axial direction on a starting base material support rod that is rotated around a vertical axis when the glass base material is manufactured. A glass base material support structure in which a pin is inserted and the starting base material support rod is supported by the support pin,
The outer diameter of the central portion of the support pin is substantially the same diameter as the inner diameter of the locking hole in a range that can be inserted into the locking hole,
The support pin has a large-diameter portion having an outer diameter larger than the central portion on the end side from the central portion, and at least a part of the large-diameter portion is in contact with the support rod for the starting base material.

  Moreover, the support pin which can solve the said subject is a support pin in the support structure of said glass base material.

Moreover, the manufacturing method of the glass base material which can solve the said subject supports the support bar for starting base materials with the support structure of said glass base material,
Glass fine particles are deposited around the starting base material supported by the starting base material support rod.

  According to the present invention, it is possible to suppress breakage of the support pins during the production of the glass base material.

It is a schematic block diagram of the manufacturing apparatus which deposits glass particulates on the starting base material supported by the support structure of the glass base material which concerns on embodiment of this invention, and manufactures a glass particulate deposit body. It is a perspective view of the upper end part of the support rod for starting base materials in FIG. It is a perspective view of the lower end part of the hanging rod in FIG. It is a schematic diagram explaining the cross section of the support structure of the glass base material which concerns on embodiment of this invention. It is a perspective view of a support pin concerning an embodiment of the present invention. It is a schematic diagram of the longitudinal cross-section of a support part at the time of using the support pin of a comparative example. It is a schematic diagram of the longitudinal cross-section of the support part explaining the influence of a load in the case of using the support pin of a comparative example. It is a schematic diagram of the longitudinal cross-section of the support part explaining the influence of a load at the time of using the support pin which concerns on embodiment of this invention. It is a schematic block diagram which shows the example which applied the support structure of the glass base material which concerns on embodiment of this invention to the storage tool of the glass base material.

[Description of Embodiment of the Present Invention]
The support structure of the glass base material according to the embodiment of the present invention is as follows.
(1) A support pin is inserted into a locking hole formed in a direction perpendicular to the axial direction to a starting base material support bar that is rotated about a vertical axis when the glass base material is manufactured. A glass base material support structure supported by the support pins,
The outer diameter of the central portion of the support pin is substantially the same diameter as the inner diameter of the locking hole in a range that can be inserted into the locking hole,
The support pin has a large-diameter portion having an outer diameter larger than the central portion on the end side from the central portion, and at least a part of the large-diameter portion is in contact with the support rod for the starting base material.
Since the large diameter portion of the support pin has a large outer diameter and a large cross-sectional area, it has a high resistance to stress. Since the large-diameter portion of the support pin is in contact with the starting base material support rod, the stress due to the load applied to the starting base material support rod is applied to the large-diameter portion of the support pin that is highly resistant to stress. . Therefore, the breakage of the support pin at the time of manufacturing the glass base material can be suppressed. When the support pin has a tapered portion whose diameter changes to the diameter of the large diameter portion, the large diameter portion includes the tapered portion.

(2) The locking hole has an inner diameter that tapers outward at its end,
The large-diameter portion is provided with a tapered portion whose outer diameter extends in a tapered shape so as to contact the tapered inner surface of the end portion of the locking hole.
As a result, the inner surface of the end portion of the locking hole of the support rod for the starting base material and the outer surface of the tapered portion of the support pin come into contact with each other. Further, since the outer edge of the locking hole is not perpendicular due to the taper, the stress due to the load of the starting base material is less likely to concentrate on the outer edge. As a result, stress concentration in a specific narrow region is unlikely to occur, so that breakage of the support pin can be suppressed.

(3) The support pin is divided into a screw part and a nut part, and the nut part is attached after the screw part is inserted into the locking hole.
Thus, since the screw portion is inserted into the locking hole and the nut portion is attached, the attaching operation of the support pin is easy, and the attached support pin can be reliably fixed. Also, since the starting base material support rod is sandwiched from both sides, the adhesion between the support pin and the starting base material support rod is increased, and stress due to the load of the starting base material is less likely to concentrate on a specific location. Breakage can be further suppressed.

(4) The ratio of the minimum outer diameter of the central portion of the support pin to the maximum outer diameter of the large diameter portion is 1.5 or more.
Since the maximum outer diameter of the large diameter portion of the support pin is 1.5 times or more larger than the minimum outer diameter of the central portion, the cross-sectional area becomes 2.25 times or more, and the resistance to the stress of the large diameter portion of the support pin is strong, Breakage of the support pin can be suppressed.

In addition, the support pin according to the embodiment of the present invention,
(5) A support pin in the glass base material support structure according to any one of (1) to (4) above.
Since the support pin is not easily broken, by using the support structure of the glass base material using the support pin, it is possible to prevent the support pin from being broken and the glass base material from falling.

Moreover, the manufacturing method of the glass base material which concerns on embodiment of this invention,
(6) The supporting base for the starting base material is supported by the supporting structure for the glass base material according to any one of (1) to (4) above,
Glass fine particles are deposited around the starting base material supported by the starting base material support rod.
By supporting the support rod for the starting base material with the support structure for the glass base material as described above, the support pin breaks and the glass base material falls when the glass base material is manufactured, such as when glass particles are deposited. Can be prevented. Further, since the support pin is less likely to deteriorate, the number of times it can be used repeatedly increases, and it is not necessary to frequently replace the support pin with a new one (auxiliary material), so that the cost of the auxiliary material can be suppressed.

[Details of the embodiment of the present invention]
Specific examples of the glass base material support structure, the support pins, and the glass base material manufacturing method according to the embodiment of the present invention will be described below with reference to the drawings.
In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included.

Hereinafter, an example of an embodiment of a glass base material support structure, a support pin, and a glass base material manufacturing method according to the present invention will be described with reference to the drawings.
First, for example, a case where an optical fiber preform is manufactured by a VAD (Vapor Phase Axial Deposition) method which is an example of a glass manufacturing method will be described.

  As shown in FIG. 1, in the VAD method, a starting base material support rod 1 is connected to a suspension rod 2 of a gripping mechanism and suspended in a reaction vessel 3. In this state, the suspension bar 2 is rotated about the axis so that the starting base material support bar 1 is also rotated about the axis, and glass fine particles generated by the burner 4 are sprayed onto the starting base material support bar 1 to form glass. A fine particle deposit (glass base material) 5 is manufactured. The burner 4 generates glass fine particles by a flame hydrolysis reaction from a glass raw material gas, a combustible gas, and an auxiliary combustible gas.

  And the glass particulate deposit 5 manufactured in this way is made transparent by performing a dehydration process or a sintering process, and then a stretching process or the like is appropriately performed to become a glass preform for an optical fiber.

  Next, a support structure for supporting the glass fine particle deposit 5 by supporting the starting base material support rod 1 on the suspension rod 2 will be described.

  As shown in FIG. 2 as an example, a starting base material support rod 1 used as a starting base material for the VAD method includes a connecting portion 1a connected to a suspension rod 2 of a gripping mechanism such as a manufacturing apparatus or a transport apparatus, and a target. And a seed rod portion 1b. Each of the connecting portion 1a and the seed rod portion 1b is made of quartz glass, and a seed rod portion 1b formed in a columnar shape is integrally provided below the connecting portion 1a.

  A locking hole 1c is formed in the connecting portion 1a of the starting base material support rod 1 in a horizontal direction orthogonal to the axial direction. Further, the inner diameter of the end portion 1d of the locking hole 1c is chamfered for the purpose of preventing chipping and the like, and thus is widened toward the outside. The locking hole 1 c is a hole for supporting the starting base material support rod 1 on the suspension rod 2. Support pins 10 are inserted into the locking holes 1c, and both ends of the support pins 10 protrude from the locking holes 1c, and holes of the fitting portions 2a formed in the hanging rod 2 as shown in FIG. Fitted.

As shown in FIG. 4, in the fitting portion 2 a, the holding plate 6 is fastened with the bolt 7, and the connecting portion 1 a of the starting base material support rod 1 is fastened by the holding plate 6. You may make it assist the support by.
In this way, the starting base material support bar 1 is supported by the suspension bar 2 by the support pins 10 and is suspended.

  In this way, by suspending and supporting the starting base material support rod 1, glass fine particles are deposited on the starting base material support rod 1, and dehydration for converting the formed glass fine particle deposit 5 into a transparent glass is possible. Sintering or drawing of an optical fiber from a transparent glass preform is performed. The method for producing the glass particulate deposits 5 by depositing glass particulates on the starting base material support rod 1 is not limited to the core attachment of the VAD method, but jacketing (formation of clad portion) or OVD (Outside Vapor). Other manufacturing methods such as the Phase Deposition method may be used.

Next, the support pin of this embodiment will be described in detail with reference to FIG.
As shown in FIG. 5, the support pin 10 is divided into a screw portion 11 and a nut portion (an example of a large diameter portion) 12. The screw portion 11 includes a central portion 11a, a large diameter portion 11b, And a threaded portion 11c.
The outer diameter of the central portion 11a of the screw portion 11 is formed to be substantially the same as the inner diameter other than the end portion 1d of the locking hole 1c. Further, the large diameter portion 11b is formed on the side opposite to the threaded portion 11c so that the outer diameter is larger than the outer diameter of the central portion 11a. For example, the minimum of the central portion 11a and the large diameter portion 11b, The ratio of the maximum outer diameter is 1.5 or more. Moreover, the nut part 12 is attached to the end part side from the center part 11a, and the outer diameter is larger than the center part 11a. For example, the ratio of the minimum and maximum outer diameters of the center part 11a and the nut part 12 is 1.5 or more. is there.

Further, the large-diameter portion 11b is provided with a tapered portion 11d having an outer diameter that tapers from the boundary with the central portion 11a. The tapered portion 11d is a portion whose outer diameter extends in a tapered shape so as to follow the inner surface of the end 1d of the locking hole 1c. Further, the nut portion 12 on the screwing side is also provided with a tapered portion 12a whose outer diameter extends in a tapered shape so as to follow the inner surface of the end portion 1d of the locking hole 1c. In addition, it is good for these taper parts 11d and the taper part 12a to be formed so that the surface area may become larger than the surface area of the inner surface of the edge part 1d. That is, it is preferable that the outer edge protrudes outside the locking hole 1c in a state where the tapered portion 11d and the tapered portion 12a are inserted into the locking hole 1c.
Further, the support pin 10 is inserted into the through hole 2b and the locking hole 1c after the screw portion 11 is inserted, and then the nut portion 12 is screwed into the threaded portion 11c, as shown in FIG. The weight of the base material support rod 1 is supported.

[Example of support pin and comparative example]
Next, in the support structure of the glass base material of the present embodiment, the difference between the case where the support pin 10 of the example of the present embodiment is used and the case where the support pin 20 of the comparative example is used is shown in FIGS. Will be described with reference to FIG.

[When using the support pin of the comparative example]
The case where the support pin of the comparative example is used in the glass base material support structure of the present embodiment will be described.
FIG. 6 shows a longitudinal section in which the support pin 20 of the comparative example is passed through the through hole 2b and the locking hole 1c of the support portion 1a in the fitting portion 2a of the hanging rod 2.
The support pin 20 of the comparative example is a round bar having a constant outer diameter. In the part shown by A in FIG. 6, it can be seen that a gap is formed between the taper-shaped part of the end 1d of the locking hole 1c and the support pin 20 of the comparative example.

Since there is a gap as described above, as shown in FIG. 7, when a load C is applied due to the weight of the starting base material 1, the support pin 20 of the comparative example is bent so that the end side warps upward.
The support pin 20 bent in this way has, for example, a corner portion of the locking hole 1c on the upper surface thereof and the support pin 20 of the comparative example in point contact (or line contact), and stress is concentrated (B1 in FIG. 7). Further, on the lower surface of the support pin 20, for example, a corner portion of the fitting portion 2a and the support pin 20 of the comparative example are in point contact or line contact, and stress is concentrated (B2 in FIG. 7).

  In this way, stress concentrates at specific locations on the upper surface and the lower surface of the support pin 20, and stress concentrates due to point contact (or line contact). For this reason, the support pin 20 of the comparative example is easily broken, and the support pin replacement frequency (use limit) of the support pin 20 of the comparative example at the time of manufacturing the glass base material is limited to 50 times.

[When using the support pins of the example]
The case where the support pin of an Example is used in the support structure of the glass base material of this embodiment is demonstrated.
An example is the support pin 10 described in the above-described embodiment, and the configuration thereof is as shown in FIG. 5 described above. In this embodiment, the ratio between the minimum and maximum outer diameters of the central portion and the end portion is 1.5 or more, and the taper angles of the taper portion 11d and the taper portion 12a are the same (45 °) as the hole side.
That is, as shown in FIG. 8, the support pin 10 of the embodiment is formed in a tapered shape along the inner surface of the end 1d at the end 1d on both sides of the locking hole 1c. For this reason, the space | gap between the support pin 10 and the locking hole 1c does not generate | occur | produce like the case where the support pin 20 of the said comparative example is used, but the load C is applied with the weight of the starting base material 1. Is less likely to warp. Thereby, unlike the comparative example, the location where stress concentrates due to point contact (or line contact) hardly occurs. On the lower surface of the support pin 10, stress concentrates on the contact portion (D in FIG. 8) between the fitting portion 2a and the large-diameter portion 11b of the support pin 10 and the nut portion (D in FIG. 8) and the tapered portions 11d and 12a, but there is no gap. , Contact with the surface instead of point contact (or line contact). Moreover, in this location, since the outer diameter of the support pin 10 is large, the cross-sectional area is large and the resistance to stress is strong. For this reason, the support pin 10 is less likely to break than the support pin 20 of the comparative example. The allowable load is 2.4 when the comparative example is 1. Moreover, the support pin replacement frequency (use limit) of the support pin 10 at the time of manufacture of a glass base material is 100 times or more.

  As described above, according to the embodiment of the present invention, the support structure for the glass base material is formed in the direction perpendicular to the axial direction on the starting base material support rod 1 that is rotated around the vertical axis when the glass base material is manufactured. A support pin 10 is inserted into the formed locking hole 1 c, and the starting base material support rod 1 is supported by the support pin 10. The outer diameter of the central portion 11a of the support pin 10 is substantially the same as the inner diameter of the locking hole 1c as long as it can be inserted into the locking hole 1c. Further, the outer diameter of the large diameter portion 11b and the nut portion 12 provided on the end side from the central portion 11a of the support pin 10 is larger than the outer diameter of the central portion 11a, and at least one of the large diameter portion 11b and the nut portion 12 is present. The portion is in contact with the support rod 1 for the starting base material.

  For this reason, even if a load is applied to the starting base material support rod 1 due to the weight of the starting base material 1, the large diameter portion 11b and the nut portion 12 having a large diameter are in contact with the starting base material support rod 1, The stress due to the load applied to the starting base material support rod 1 is applied to the large-diameter portion 11b and the nut portion 12 of the support pin 10 having high resistance to stress. Therefore, breakage of the support pin 10 at the time of manufacturing the glass base material can be suppressed. Further, since the breakage of the support pin 10 can be suppressed without changing the shape of the locking hole 1c of the starting base material support rod 1, conventional equipment and members can be used as they are.

Further, the locking hole 1c of the starting base material support rod 1 has an inner diameter that widens in a tapered shape toward the outside at the end 1d, and a large-diameter portion so as to contact the tapered inner surface of the end 1d. 11b and the nut part 12 are provided with tapered parts 11d and 12a, respectively, whose outer diameters are tapered.
As a result, the inner surface of the end portion 1d of the locking hole 1c and the outer surfaces of the tapered portions 11d and 12a are in contact with each other, so that stress due to the load of the starting base material 1 is unlikely to concentrate on the outer edge portion. Since stress concentration in these specific narrow regions is less likely to occur, breakage of the support pin 10 can be suppressed.

Moreover, the support pin 10 is divided | segmented into the screw part 11 and the nut part 12, and the nut part 12 is attached after inserting the screw part 11 in the latching hole 1c.
Thus, since the screw part 11 is inserted into the locking hole 1c and the nut part 12 is attached, the attaching operation of the support pin 10 is easy, and the support pin 10 can be reliably fixed. Further, since the starting base material support rod 1 is sandwiched between the large diameter portion 11b and the nut portion 12 from the axial direction side, the adhesion between the support pin 10 and the starting base material support rod 1 is increased, and the starting base material support rod is provided. The stress due to the load of 1 becomes difficult to concentrate on a specific location, and the breakage of the support pin 10 can be further suppressed.

  Further, since the maximum outer diameter of the end portion of the support pin 10 (the large diameter portion 11b and the nut portion 12 of the screw portion 11) is 1.5 times or more larger than the minimum outer diameter of the central portion 11a, the cross-sectional area is 2.25. The resistance to the stress at the ends of the support pin 10 (the large diameter portion 11b and the nut portion 12) of the support pin 10 is strong, and the breakage of the support pin 10 can be suppressed.

  Since the support pin 10 of the present embodiment is not easily broken as described above, the support pin 10 can be manufactured even if a large glass base material is manufactured by using the glass base material support structure using the support pin 10. Breaks and the glass base material can be prevented from falling.

  Moreover, the manufacturing method of the glass base material of the glass base material of this embodiment supports the starting base material support rod 1 by the glass base material support structure as described above. It is possible to prevent the support pin 10 from being broken and the glass base material from falling during the production of the glass base material. Further, since the support pin 10 is less likely to deteriorate, the number of times it can be used repeatedly increases, and it is not necessary to frequently replace the support pin 10 with a new one (auxiliary material), thereby reducing the cost of the auxiliary material.

[Application example of the embodiment of the present invention]
Next, as an application example to which the support pin according to the embodiment of the present invention is applied, an example of a glass base material storage tool will be described with reference to FIG. FIG. 9 is a schematic configuration diagram of a glass base material storage tool, where (a) is a front view and (b) is a side view.
This application example is an application example in which the support pin 10 and the starting base material support rod 1 according to the embodiment of the present invention are used in a storage tool used in a facility for storing a glass base material. In addition, the same code | symbol is attached to the part which is common in embodiment, The detailed description is abbreviate | omitted.
As shown in (a) of FIG. 9, the storage tool 30 includes a support portion 31 and a support pin 10. As shown in FIGS. 9A and 9B, the support portion 31 is composed of two bars that project from a wall surface 32 of a facility or the like in a substantially horizontal direction. Further, the two bars are each provided with a recess 31a.

Next, a method for suspending the starting base material support rod 1 and the glass base material 5 on the storage tool 30 will be described.
The screw portion 11 of the support pin 10 shown in FIG. 5 is inserted into the locking hole 1c of the starting base material support rod 1 shown in FIG. 3, and the nut portion 12 is screwed. Next, the large-diameter portion 11b and the nut 12 of the support pin 10 are respectively placed in the recess 31a and supported by the support portion 31 (two bars) as shown in FIGS. 9 (a) and 9 (b). In this way, the starting base material 1 can be suspended and stored.
Also in this application example, the effect that the breakage of the support pin 10 due to the load of the starting base material support rod 1 and the glass base material 5 can be suppressed can be obtained in the same manner as the effect of the above-described embodiment. The starting base material support rod 1 and the glass base material 5 can be prevented from falling.

DESCRIPTION OF SYMBOLS 1 Starting base material support rod 1a Connecting part 1b Seed bar part 1c Locking hole 1d End part 2 Hanging rod 2a Fitting part 2b Through hole 3 Reaction vessel 4 Burner 5 Glass particulate deposit (glass base material)
6 Holding plate 7 Bolt 10 Support pin 11 Screw part 11a Central part 11b Large diameter part 11c Threaded part 11d Tapered part 12 Nut part 12a Tapered part 20 Comparative support pin 30 Storage tool 31 Support part 31a Recessed part

Claims (6)

A support pin is inserted into a locking hole formed in a direction perpendicular to the axial direction to a starting base material support bar that is rotated around a vertical axis during glass base material manufacture, and the starting base material support bar is inserted into the support pin. A supporting structure of the glass base material supported by
The outer diameter of the central portion of the support pin is substantially the same diameter as the inner diameter of the locking hole in a range that can be inserted into the locking hole,
A glass base material having a large-diameter portion whose outer diameter is larger than that of the central portion on the end side from the central portion of the support pin, and at least a part of the large-diameter portion is in contact with the support rod for the starting base material Support structure. The locking hole has an inner diameter that tapers outward at its end,
2. The glass base material according to claim 1, wherein the large-diameter portion is provided with a tapered portion having an outer diameter that tapers so as to contact a tapered inner surface of an end portion of the locking hole. Support structure.   The glass base material support structure according to claim 1 or 2, wherein the support pin is divided into a screw part and a nut part, and the nut part is attached after the screw part is inserted into the locking hole.   The glass base material support structure according to any one of claims 1 to 3, wherein a ratio of a minimum outer diameter of a central portion of the support pin to a maximum outer diameter of a large diameter portion is 1.5 or more. .   The support pin in the support structure of the glass base material of any one of Claims 1-4. The support bar for the starting base material is supported by the support structure for the glass base material according to any one of claims 1 to 4,
A method for producing a glass base material, wherein glass fine particles are deposited around the starting base material supported by the starting base material support rod.

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