JP2798207B2 - Method and apparatus for forming precision spherical glass gob - 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 and an apparatus for forming a precision glass gob used for mold optics (MO) optical parts and the like.

[0002]

2. Description of the Related Art As a method of forming a glass gob (glass lump) used as an MO optical component, there is, for example, a method described in Japanese Patent Application Laid-Open No. 2-14839.

That is, as shown in FIG. 4, a molten glass block 3 is dropped by dropping the molten glass 2 flowing down from an outflow pipe 1 naturally or by cutting it with a cutting blade (not shown). The molten glass lump 3 is received by the concave portion of the molding die 4, and at this time, a gas such as air or an inert gas is blown out from the fine holes 6 opened in the concave portion 5.

The molten glass lump 3 that has fallen into the recess 5 of the mold 4 is blown from below by a gas such as air.
Is rotated and spherically formed while slightly floating with almost no contact with the inner surface 5a. The spheroidized molten glass lump 3 is cooled while floating in the concave portion 5, and is taken out of the molding die 4 after the surface is lowered to a temperature below the softening point.

[0005]

In the above-mentioned conventional method for forming a glass gob, the molten glass lump is floated by gas blown out from pores 6 opening into the concave portion 5 of the molding die 4. The shape is unstable, and it is easy to vibrate up and down and left and right by the air current, and it is difficult to smoothly rotate and spherically form the recess 5.
Therefore, in the above-mentioned method for forming a glass gob, it was extremely difficult to form a large amount of glass gob with high sphericity with good reproducibility.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to reproduce a desired precision glass gob with extremely high sphericity by using a simple molding apparatus. An object of the present invention is to provide a method and apparatus for forming a precision glass gob that can be formed well.

[0007]

According to a first aspect of the present invention, there is provided a method for forming a precision spherical glass gob from a molten glass, wherein the molten glass is formed on a mold in a direction perpendicular to a longitudinal direction. The melt is supplied to a long groove having an arc-shaped cross section and is held on the long groove.
By blowing gas onto the lath mass, the molten glass mass held on the long groove is moved along the longitudinal direction on the long groove.
It is characterized in that the molding while rolling Te.

According to a second aspect of the present invention, in the method for forming a precision spherical glass gob, at least one of the longitudinal end faces of the long groove has a spherical shape. Things.

According to a third aspect of the present invention, in the method for forming a precision spherical glass gob according to the second aspect, the method of rolling a molten glass lump on the long groove includes rolling the molten glass lump in a longitudinal direction along a side surface of the long groove. After moving, at the end of the long groove whose longitudinal end face shape is spherical among the both ends of the long groove, the molten glass block is formed while being rolled along the end face of the long groove. Things.

According to a fourth aspect of the present invention, there is provided a method for forming a precision spherical glass gob according to any one of the first to third aspects, wherein the length of the long groove in the longitudinal direction is at least twice the length of the long groove in the width direction. It is characterized by the following.

[0011] The method for forming a precision spherical glass gob according to claim 5 is the method according to any one of claims 1 to 4, wherein:
In the method of rolling a molten glass lump, by vibrating the molding die or by blowing gas from the inner surface of the molding die to form a gas cushion at an interface between the molten glass lump and the long groove, the molding die and the molten glass It is characterized by preventing fusion with a lump.

According to a sixth aspect of the present invention, there is provided a precision spherical glass gob forming apparatus for forming a precision spherical glass gob from molten glass, wherein the precision spherical glass gob is formed on a molding die for holding a molten glass block made of the molten glass. Formed in the
A long groove whose cross section orthogonal to the longitudinal direction has an arc shape,
Rolling means for blowing a gas onto the molten glass and rolling the molten glass lump along the long groove in the longitudinal direction .

According to a seventh aspect of the present invention, in the apparatus for forming a precision spherical glass gob according to the sixth aspect, at least one of the longitudinal end faces of the long groove is spherical. Things.

According to an eighth aspect of the present invention, in the apparatus for forming a precision spherical glass gob according to the sixth or seventh aspect, the rolling means comprises a first rolling means for rolling the molten glass lump in a longitudinal direction along a side surface of the long groove. Rolling means for rolling the molten glass block along the end face of the long groove at the end face of the long groove whose longitudinal end face shape is spherical among both ends of the long groove. It is characterized by being.

According to a ninth aspect of the present invention, in the apparatus for forming a precision spherical glass gob according to any one of the sixth to eighth aspects, the length of the long groove in the longitudinal direction is at least twice the length of the long groove in the width direction. It is characterized by the following.

The molding apparatus of the precision spherical gob of claim 10, in any one of claims 6-9, said mold
Vibration means for vibrating the molding die or gas discharging means for discharging gas from the inner surface of the molding die to prevent fusion with the molten glass lump is provided.

[0017]

[0018]

In the method for forming a precision spherical glass gob according to the first aspect, the molten glass is supplied to the long groove of the mold and is held on the long groove. Since the shape of the cross section perpendicular to the longitudinal direction of the long groove is an arc shape, the molten glass
By spraying the molten glass mass held on the long groove while cooling it along the longitudinal direction of the long groove, a spherical precision spherical glass gob having a diameter substantially equal to the width of the long groove is extremely formed. It can be easily molded.

In the method for molding a precision spherical glass gob according to the second aspect, the longitudinal end face of the long groove has a spherical shape at least one of both end faces in the longitudinal direction.
The glass gob that has been made spherical by rolling in the longitudinal direction along the side surface of the long groove can maintain the spherical shape on the end surface having a spherical end surface shape in the longitudinal direction.

In the method for forming a precision spherical glass gob according to the third aspect, the molten glass is extremely easily spheroidized by rolling the molten glass lump in the longitudinal direction along the side surface of the long groove. Thereafter, at both ends of the long groove, at the end surface of the long groove whose longitudinal end surface shape is spherical, by forming while rolling the molten glass block along the end surface of the long groove, the spheroidized molten glass is formed. Further, it can be formed into a precision spherical glass gob with high sphericity.

In the method for forming a precision spherical glass gob according to claim 4, since the length of the long groove in the longitudinal direction is at least twice the length of the long groove in the width direction, the molten glass lump held on the long groove is formed. Is cooled while being rolled along the longitudinal direction of the long groove, whereby a precision spherical glass gob having a diameter substantially equal to the width of the long groove can be formed very easily.

In the method of forming a precision spherical glass gob according to claim 5, the gas is formed at the interface between the molten glass block and the long groove by vibrating the molding die or by blowing gas from the inner surface of the molding die. The fusion of the mold and the molten glass lump can be prevented very easily.

In the apparatus for molding a precision spherical glass gob according to a sixth aspect of the present invention, the shape of a cross section orthogonal to the longitudinal direction, formed on a mold for holding a molten glass block made of the molten glass, is an arc shape. To the long groove and the molten glass
A gas is blown to move the molten glass block in the longitudinal direction on the long groove.
Because and a rolling means for rolling along, the length molten glass block held in-groove is cooled while rolling along the longitudinal direction of the elongated groove, substantially the same as the width of the long groove A spherical precision spherical glass gob having a diameter of?

In the apparatus for molding a precision spherical glass gob according to claim 7, the longitudinal end face of the long groove has a spherical shape at least one of both end faces in the longitudinal direction.
The glass gob that has been made spherical by rolling in the longitudinal direction along the side surface of the long groove can maintain the spherical shape on the end surface having a spherical end surface shape in the longitudinal direction.

In the apparatus for forming a precision spherical glass gob according to claim 8, the rolling means comprises: first rolling means for rolling the molten glass block in the longitudinal direction along the side surface of the long groove;
At the end face of the long groove whose longitudinal end face shape is spherical among the both ends of the long groove, because it is the second rolling means for rolling the molten glass lump in a state along this long groove end face,
After the molten glass ingot is rolled in the longitudinal direction along the side surface of the long groove by the first rolling means, the end face of the long groove whose longitudinal end face shape is spherical among the both end faces of the long groove is the end face of the long groove. By rolling the molten glass lump by the second rolling means in the state along the above, a precision spherical glass gob with extremely high sphericity can be formed extremely easily.

In the apparatus for forming a precision spherical glass gob according to the ninth aspect, the length of the long groove in the longitudinal direction is at least twice the length of the long groove in the width direction. Is cooled while rolling along the longitudinal direction of the long groove, and a substantially spherical or spherical precision glass gob having a diameter substantially equal to the width of the long groove can be formed very easily.

According to a tenth aspect of the present invention, there is provided an apparatus for molding a precision spherical glass gob , wherein the molding die is fused with the molten glass lump.
Vibration means for vibrating the molding die and gas discharging means for discharging gas from the inner surface of the molding die are provided so as to prevent the vibration of the molding die, or blowing out gas from the inner surface of the molding die, By forming a gas cushion at the interface between the molten glass lump and the long groove, fusion between the mold and the molten glass lump can be extremely easily prevented.

[0028]

[0029]

Embodiments will be described below with reference to the drawings. 1 to 3 show a method and an apparatus for molding a precision spherical glass gob according to an embodiment of the present invention.
FIG. 1 is a cross-sectional view showing one example of a schematic configuration and an example of a molding procedure used in a molding method of a precision spherical glass gob, FIG. 2 is a top view of a molding die used in the method of molding a precision spherical glass gob, and FIG. FIG. 3 is a sectional view taken along the line III-III in FIG. 2. The mold shown in FIG. 1 is shown as a cross-sectional view along the line II in FIG.

As shown in FIG. 1, a precision spherical glass gob forming apparatus 10 of the present invention comprises a flow control pipe 12 from a glass melting furnace (not shown) to which molten glass 11 melted in the melting furnace is supplied. It has. A pipe heating heater 13 is provided around the flow control pipe 12.

Although not shown, the flow control pipe 1
Inside 2, a thermocouple and a temperature control device are provided. The temperature of the molten glass 11 in the flow control pipe 12 is detected by the thermocouple, and the electric power of the pipe heating heater is controlled by the temperature control device so that the molten glass 11 in the flow control pipe 12 becomes a predetermined temperature. Is controlled.

Near the tip of the flow control pipe 12, cutting blades 14 and 15 are provided.
5 is opened and closed at a predetermined timing, so that the drop portion 11a of the molten glass 11 flowing out of the flow control pipe 12
Is cut and dropped by an appropriate amount.

Below the flow control pipe 12, a long groove 1
Mold 1 made of an appropriate material having 6, 16,...
., And are arranged, for example, along the periphery of a rotating table (not shown). As shown in FIG.
Each of the long grooves 16, 16,... Has a circular arc shape in a cross section orthogonal to the longitudinal direction. Also, as shown in FIGS. 1 and 2, the longitudinal end faces of the long grooves 16, 16,... Are spherical. Furthermore, the long grooves 16, 1
The length in the longitudinal direction of 6,...
It is 3.5 times the length in the width direction. In addition, the surfaces of the long grooves 16, 16,... Are mirror-finished.

A vibrator 21 is attached to each of the molding dies 17, 17...
Are configured to be vibrated.

Are provided with a heater, a thermocouple and a temperature controller (not shown) so that the molten glass lump 11b can be cooled at an appropriate speed. I have. The molding die 17,
The temperature of 17 ... is detected, and the temperature controller
The amount of electricity of the heater is controlled such that the temperature of the molding dies 17, 17,... Becomes a predetermined temperature. Further, the mold 1
Are configured to be cooled by cooling water (not shown), so that heating and cooling of the molds 17, 17,... Are performed quickly.

Below the flow control pipe 12, a first gas discharge pipe 18 and a second gas discharge pipe 19 are provided. The first gas discharge pipe 18 and the second gas discharge pipe 19 are configured to blow out an inert gas such as nitrogen gas, air, or the like. These first gas discharge pipes 18
The second gas discharge pipe 19 is configured so that an appropriate gas discharge angle and gas discharge amount can be set.

A method for forming a precision spherical glass gob using the forming apparatus 10 configured as described above will be described below.

First, a switch (not shown) of the molding apparatus 10 is turned on to move the molding dies 17, 17,... In a predetermined rotation cycle, and the flow control pipe 12 is heated by the pipe heating heater 13. Further, a glass melting furnace (not shown) is operated to supply the molten glass 11 melted in the melting furnace into the flow control pipe 12. At this time, the temperature of the flow control pipe 12 is adjusted so that the viscosity logη of the molten glass 11 in the flow control pipe 12 becomes an optimum value of about 0.5 to 3.0 poise.

When the molten glass 11 is sufficiently supplied into the flow control pipe 12 and the operation of the molding apparatus 10 is in a steady state, the initial position shown in FIG. 1A passes through the standby position shown in FIG. Then, the drop portion 11a of the molten glass 11 cut by the cutting blades 14 and 15 is dropped onto the long groove 16 of the empty molding die 17 moved to the molten glass dropping position in FIG.

That is, the initial position (the position (A) in FIG. 1)
When the empty mold 17 that has started from above moves to the position directly below the flow control pipe 12 (position (C) in FIG. 1) via the position (B) in FIG. Is cut and dropped on the long groove 16 of the mold 17.

When the mold 17 holding the cut and dropped molten glass 11 (the molten glass lump 11b) has moved to a position immediately below the first gas discharge pipe 18 (position (D) in FIG. 1), The gas is blown out from the first gas discharge pipe 18, and this gas is blown into the interface between the molten glass lump 11 b and the long groove 16. The blown gas causes the molten glass lump 1
A gas cushion is formed at the interface between 1b and the long groove 16,
In this state, the molten glass lump 11b moves longitudinally to the end face of the long groove 16 while rolling along the side surface of the long groove 16.

When the molten glass lump 11b reaches the side surface at the end of the long groove 16, the molten glass lump 11b
The temperature of the mold 17 is adjusted so that b is still in a softened state. In the present embodiment, the molding die 17 is
It is assumed that the operation of the vibrator 21 is started at the time when it moves to the molten glass dropping position (C).

Thereafter, the discharge of the gas from the first gas discharge pipe 18 is terminated, and the molding die 17 is moved to a position immediately below the second gas discharge pipe 19 (position (E) in FIG. 1). Of the gas from the gas discharge pipe 19 is started. The blown gas rolls the molten glass lump 11b along the end face of the long groove 16 for a predetermined time. Note that, also in this case, the molten glass lump 11b is rolled while a gas cushion is formed at the interface between the molten glass lump 11b and the long groove 16.

After the molten glass lump 11b is rolled into a true spherical shape by cooling, the surface thereof is cooled to a temperature lower than the softening temperature, and a precision spherical glass gob 20 is formed. Is completed.

The timing of cutting by the cutting blades 14, 15 and the timing of gas discharge from the first and second gas discharge pipes 18, 19 are determined by the rotation cycle of the molds 17, 17,. It is determined in consideration of the time required for the cooling process of the positions (C) to (G). The cooling time between the positions (C) to (D) in FIG. 1, that is, the time required from the cutting and dropping of the molten glass 11 to the gas discharge of the first gas discharge pipe 18 is usually 0.1 to 1.0. On the order of seconds.

Further, the cooling time between the positions (D) to (E) in FIG. 1, that is, the discharge of the gas from the first gas discharge pipe 18 is completed, and the molding die 17 is moved to the second gas discharge pipe. 1
9 (position (E) in FIG. 1), and the time required to start blowing gas from the second gas discharge pipe 19 is usually about 0.1 to 1.0 second. is there.

Further, the rolling time at the position (E) in FIG. 1, ie, the blowing of the gas from the second gas discharge pipe 19 starts, and the blown gas causes The molten glass lump 11b rolls for a predetermined time along the side surface of the end, and the second gas discharge pipe 19b.
The time required to complete the discharge of the gas is usually 2 to 2.
It is about 20 seconds.

The glass gob 20 is cooled at a position (F) in FIG. 1 while being controlled by a temperature control unit (not shown), and is cooled at a take-out position (a position (G) in FIG. 1) by vacuum suction means or molding. The mold 17 is taken out by a known means such as a tilting means. The empty mold 17 moves again to the initial position (the position (A) in FIG. 1) and is used for the next glass gob molding.

In the molding method using the molding device 10 for the precision spherical glass gob 20 configured as described above, the molten glass 11 is supplied to the long groove 16 of the mold 17 and is held on the long groove 16. Since the shape of the cross section orthogonal to the longitudinal direction of the long groove 16 is an arc shape, the molten glass lump 11b held on the long groove is cooled while rolling along the longitudinal direction of the long groove 16, and A precision spherical glass gob 20 having a diameter substantially equal to the width can be easily formed.

Further, since the longitudinal end surfaces of the long groove 16 are spherical, the glass gob which is rolled in the longitudinal direction along the side surface of the long groove 16 is formed into a spherical shape.
At the end face of No. 6, the spherical shape can be maintained.

Further, by forming the molten glass lump on the end face of the long groove 16 while rolling the molten glass lump along the end face of the long groove 16, the spheroidized molten glass 11 is formed.
Is formed into a precision spherical glass gob 20 having a higher sphericity. In addition, since the surfaces of the long grooves 16, 16,... Are mirror-finished, the surface of the precision spherical glass gob 20 is mirror-finished.

Since the vibrator 21 is attached to the molding dies 17, 17,..., The molding dies 17, 17,.
The fusion between the long groove 16 of the molding die 17 and the molten glass lump 11b is effectively prevented. In this embodiment, the molding die 1
By inclining 7, 17, ... at an appropriate angle,
The long grooves 16, 16,... Are inclined at an appropriate angle, and the molten glass lump 1 extends along the side surfaces of the inclined long grooves 16, 16,.
By rolling 1b, the rolling of the molten glass lump 11b becomes smoother, the forming efficiency of the precision spherical glass gob becomes extremely high, and the sphericity of the precision spherical glass gob is improved.

In the molding method using the precision spherical glass gob molding apparatus 10 according to the present embodiment, the molten glass lump flowing down from the flow control pipe 12 is cut by the cutting blades 14 and 15. Known cutting methods such as infrared radiation, high-frequency heating, rapid heating means by oxyhydrogen flame, cutting by rapid lowering of a mold, and cutting by natural dropping can be applied.

Further, the precision spherical glass gob 20 of this embodiment is used.
In the molding method using the molding apparatus 10 of
The vibrator 21 is attached to 7, 17,..., And by the operation of the vibrator 21, the forming dies 17, 17,.
Are vibrated to prevent fusion of the long grooves 16 of the molding dies 17, 17... And the molten glass lump 11b.
7, 17,... Are provided with pores in the long grooves 16, 16,.
By forming a gas cushion at the interface between the molds 17, 16 and so on, it is possible to prevent the fusion between the molds 17, 17 and the molten glass lump 11b.

Further, the precision spherical glass gob 20 of this embodiment is used.
In the molding method using the molding apparatus 10 of
The longitudinal end surfaces of the long grooves 16, 17,... Are spherical, but the molding dies 17, 17,.
.. May have only one of the longitudinal end faces of the long grooves 16, 16,. That is, the long groove 1
The molten glass lump 11b dropped on 6, 16,... Is rolled along the side surface of the long groove 16, and then the molten glass lump 11b is removed from the spherical end surface of both end surfaces of the long groove 16. The precision spherical glass gob 20 may be formed by rolling along the end face.

In this embodiment, the long grooves 16, 1
The length in the longitudinal direction of 6...
The length in the width direction was 3.5 times, but it was confirmed that a precision glass gob with a high sphericity equivalent to that of the present example could be formed if the length was twice or more.

[0057]

According to the method for forming a precision spherical glass gob of the first aspect, the molten glass is supplied to the long groove of the mold and is held on the long groove. Since the shape of the cross section orthogonal to the longitudinal direction of the long groove is an arc shape, the molten glass
The molten glass lump held on the long groove is cooled while rolling along the longitudinal direction of the long groove by blowing a gas on the spherical glass gob, thereby forming a spherical precision spherical glass gob having a diameter substantially equal to the width of the long groove. Can be formed very easily.

In the method for forming a precision spherical glass gob according to the second aspect, the glass gob that has been spherical by being rolled in the longitudinal direction along the side surface of the long groove has an end face having a spherical shape in the longitudinal direction. The spherical shape can be maintained.

In the method for forming a precision spherical glass gob according to the third aspect, the molten glass is extremely easily spheroidized by rolling the molten glass lump in the longitudinal direction along the side surface of the long groove. After that, at the end face of the long groove whose longitudinal end face shape is spherical among the both end faces of the long groove, the molten glass lump is formed by rolling the molten glass lump while rolling along the end face of the long groove. Can be formed into a precision spherical glass gob with higher sphericity.

In the method for forming a precision spherical glass gob according to claim 4, the molten glass mass held on the long groove is cooled while being rolled along the longitudinal direction of the long groove, so that the molten glass lump is substantially the same as the width of the long groove. A precision spherical glass gob having a diameter can be formed very easily.

In the method for forming a precision spherical glass gob according to claim 5, a gas cushion is formed at the interface between the molten glass block and the long groove by vibrating the molding die or by blowing gas from the inner surface of the molding die. The fusion of the mold and the molten glass lump can be prevented very easily.

[0062] In the precision spherical glass gob forming apparatus according to claim 6, the cross-sectional shape orthogonal to the longitudinal direction formed on the forming die for holding the molten glass block made of the molten glass is arc-shaped. To the long groove and the molten glass
A gas is blown to move the molten glass block in the longitudinal direction on the long groove.
Because and a rolling means for rolling along, the length molten glass block held in-groove is cooled while rolling along the longitudinal direction of the elongated groove, substantially the same as the width of the long groove A spherical precision spherical glass gob having a diameter of?

In the apparatus for molding a precision spherical glass gob according to claim 7, the glass gob which has been spherical by rolling in the longitudinal direction along the side surface of the long groove has an end face having a spherical shape in the longitudinal direction. The spherical shape can be maintained.

In the apparatus for forming a precision spherical glass gob according to claim 8, after the molten glass block is rolled longitudinally along the side surface of the long groove by the first rolling means, the longitudinal direction of both end faces of the long groove is reduced. On the end face of the long groove whose end face shape is spherical, by molding while rolling the molten glass lump by the second rolling means in a state along the end face of the long groove, a precision sphere with extremely high sphericity is obtained. Glass gobs can be formed very easily.

In the apparatus for forming a precision spherical glass gob according to the ninth aspect, the molten glass lump held on the long groove is cooled while rolling along the longitudinal direction of the long groove, and has a diameter substantially equal to the width of the long groove. A substantially spherical or spherical precision glass gob can be formed very easily.

According to a tenth aspect of the present invention, there is provided an apparatus for molding a precision spherical glass gob , wherein the molding die is fused with the molten glass lump.
Vibration means for vibrating the molding die and gas discharging means for discharging gas from the inner surface of the molding die are provided so as to prevent the vibration of the molding die, or blowing out gas from the inner surface of the molding die, By forming a gas cushion at the interface between the molten glass lump and the long groove, fusion between the mold and the molten glass lump can be extremely easily prevented.

[0067]

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a molding apparatus used in a method for molding a precision glass gob according to an embodiment of the present invention and an example of a molding procedure.

FIG. 2 is a top view of a molding die used in a method for molding a precision glass gob according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a cross-sectional view of a molding apparatus used in a conventional method for molding a glass gob.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Forming apparatus 11 Molten glass 11a Molten glass lump 12 Flow control pipe 13 Pipe heating heater 14, 15 Cutting blade 16, 22 Long groove 17, 23 Molding die 18 First gas discharge means 19 Second gas discharge means 20 Precision spherical glass gob 21 Vibrator

Continuation of the front page (56) References JP-A-2-14839 (JP, A) Jikken 29944 (Taisho 15) (JP, Y 1T) (58) Fields investigated (Int. Cl. ⁶ , DB name) C03B 7/08 C03B 11/00 C03B 19/10

Claims (10)

(57) [Claims] In forming a precision spherical glass gob from molten glass, the molten glass is supplied to a long groove formed on a mold and having a cross section orthogonal to the longitudinal direction in an arc shape. The molten glass mass
A method for forming a precision spherical glass gob, characterized by forming a molten glass lump held on the long groove by rolling a gas on the long groove along the longitudinal direction while rolling the molten glass lump on the long groove. 2. The method for forming a precision spherical glass gob according to claim 1, wherein at least one of both end faces in the longitudinal direction of the long groove has a spherical end face. 3. A method of rolling a molten glass lump on the long groove, comprising: rolling the molten glass lump in a longitudinal direction along a side surface of the long groove; 3. The method for forming a precision spherical glass gob according to claim 2, wherein the molten glass block is formed while rolling on the end surface of the long groove having a spherical end surface along the end surface of the long groove. 4. The precision spherical glass gob according to claim 1, wherein the length of the long groove in the longitudinal direction is at least twice the length of the long groove in the width direction. Method. 5. A method for rolling a molten glass lump on the long groove, wherein the forming die is vibrated,
Alternatively, by blowing gas from the inner surface of the mold and forming a gas cushion at an interface between the molten glass lump and the long groove, fusion of the mold and the molten glass lump is prevented. A method for forming a precision spherical glass gob according to any one of the above. 6. A molding apparatus used for forming a precision spherical glass gob from molten glass, wherein the molding apparatus is formed on a molding die for holding a molten glass mass made of the molten glass, and is orthogonal to a longitudinal direction. A long groove having an arc-shaped cross section; and rolling means for blowing gas onto the molten glass and rolling the molten glass lump along the long groove in the longitudinal direction. Precision spherical glass gob molding equipment. 7. The precision spherical glass gob forming apparatus according to claim 6, wherein at least one of both end faces in the longitudinal direction of the long groove has a spherical end face. 8. The rolling means comprises: first rolling means for rolling the molten glass lump in a longitudinal direction along a side surface of the long groove; and a longitudinal end face shape among both ends of the long groove. 8. The precision spherical shape according to claim 6, wherein the second rolling means is for rolling the molten glass block along the end face of the long groove having a spherical shape. Glass gob molding equipment. 9. The precision spherical glass gob according to claim 6, wherein the length of the long groove in the longitudinal direction is at least twice the length of the long groove in the width direction. apparatus. 10. The melting of the molding die and the molten glass lump.
The precision according to any one of claims 6 to 9, further comprising a vibrating means for vibrating the molding die or a gas discharging means for discharging gas from the inner surface of the molding die to prevent the adhesion. Spherical glass gob molding equipment.