JPH10338533A - Production of bent and tempered glass sheet and apparatus for production therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily execute the expansion of the degree of freedom in forming a bent and tempered glass sheet to be formed by utilizing its own weight of the glass sheet. SOLUTION: Cooling gas blowing means 21, 22 installed in continuation on both sides via the glass transporting path in a rapid cooler 2 are arranged in such a manner that the positions at the upstream ends in the glass sheet transporting direction vary on both sides. The bent and formed glass sheet G ejected out of a heating furnace 1 is first begun to be cooled with respect to the one surface alone and thereafter, the cooling of the other surface is started, by which the bent and tempered glass sheet is formed.

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 manufacturing a bent tempered glass sheet, and more particularly to a method and an apparatus for manufacturing a bent tempered glass sheet useful as architectural and automotive glass. It is about.

[0002]

2. Description of the Related Art Tempered glass, which is so-called safety glass, is widely used as window glass for buildings and automobiles. As a method for producing such a tempered glass, a wind-cooling tempering method is widely practiced in which cooling air is blown onto a glass sheet heated to around the softening temperature of the glass to rapidly cool the glass sheet to form a residual compressive stress layer on the surface of the glass sheet. Have been.

In particular, in the field of window glass for automobiles, there is a great demand for bent glass formed into a predetermined shape by the demands of automobile design, aerodynamic characteristics and the like. Therefore, in the air-cooling strengthening method, the heated and softened glass sheet is often subjected to bending as needed before blowing the cooling air. As a method of bending a glass plate, a method of sandwiching and heating a softened glass plate with a pair of convex and concave press dies by a tongue (hanging tool), and forming a softened glass plate horizontally transferred in a heating furnace. A method has been proposed and implemented in which a glass plate is held and held by a vertical press die while maintaining a horizontal posture.

[0004] In the forming method involving press using a mold, the step of heating and softening the glass sheet and the step of bending and forming the glass sheet are basically separate steps.
A method has been proposed in which these two steps are performed as the same step. This method is to apply a predetermined curvature to a glass plate conveying means such as a roll and a bed in a heating furnace, so that the heated glass plate gradually hangs down by its own weight and finally forms a curved surface having the curvature. It was done. This bent glass is quenched in a quenching device arranged adjacent to the heating furnace to be tempered glass. This method is an excellent manufacturing method in that it is not necessary to carry out press forming for each glass sheet. In order to make use of this feature, various improvements have been made in the past and have been put to practical use (for example, JP-B-44-14832, JP-B-48-52
42, JP-A-7-237928).

[0005] In particular, Japanese Patent Application Laid-Open No. 7-237928 discloses that a gas is blown onto one surface of a glass sheet from a heating furnace to a quenching device, and a temperature equal to or higher than its softening point is applied to both sides of the glass sheet. There is disclosed a method of intentionally causing a difference in shrinkage on both surfaces of a glass plate by giving a temperature difference in a region. This method is excellent in that the degree of freedom in forming a glass sheet is improved without being limited to the shape of the glass conveying means.

[0006]

However, in the method described in Japanese Patent Application Laid-Open No. Hei 7-237928, a gas blowing means is newly provided between the heating furnace and the quenching device separately from the quenching device for the glass plate. From the gas blowing means,
Basically, it is necessary to discharge gas at a pressure higher than that of the cooling air, and it has not always been possible to simply carry out the gas with a conventional apparatus.

[0007] In view of such circumstances, an object of the present invention is to provide a method and an apparatus for manufacturing a bending-strengthened glass sheet which can easily improve the degree of freedom in forming a glass sheet.

[0008]

In order to achieve the above object, a method for manufacturing a bent tempered glass sheet according to the present invention comprises heating a glass sheet while passing the glass sheet in a heating furnace in a substantially horizontal direction, and heating the glass sheet. A method for producing a bent tempered glass sheet which is bent by utilizing its own weight and quenched by spraying a cooling gas on both surfaces thereof in a quenching device continuously arranged in the heating furnace, wherein the cooling gas is cooled by the glass. It is characterized in that it is sprayed prior to any one surface of the plate.

By adopting such a method, it is possible to easily improve the degree of freedom in forming a glass sheet in a method for producing a bending-strengthened glass sheet in which forming is performed by utilizing the weight of the glass sheet. The method of the present invention differs from the prior art by a method of lowering the glass surface temperature before starting the cooling to some extent, and the timing of starting the cooling is made different on both sides of the glass sheet, thereby The timing lugs improve the degree of freedom in forming the glass sheet.

In the method for manufacturing a bending-strengthened glass sheet, when the cooling air is blown to one of the surfaces of the glass sheet in advance, the cooling air is blown while supporting the other surface of the glass sheet. It is preferable to attach. According to this preferred example, it is possible to prevent the conveyance posture of the glass plate from being largely distorted by the cooling gas blown from only one side.

[0011] In the method for manufacturing a bent tempered glass sheet, the cooling gas is blown in advance to one of the surfaces of the glass sheet, so that the temperature of the surface is reduced to the other surface of the glass sheet. Before the cooling gas is blown, it is preferable that the temperature be equal to or lower than the softening point of the glass plate.
More preferably, it is below the strain point of the glass plate. According to these preferred examples, it is possible to increase the degree of freedom in forming the glass sheet by making the difference in the timing of starting the cooling of the glass sheet noticeable.

According to another aspect of the present invention, there is provided a bending tempered glass sheet manufacturing apparatus, comprising: a heating furnace for heating the glass sheet; and a glass sheet carry-in port adjacent to the glass sheet carry-out port of the heating furnace. A quenching device in which cooling gas spraying means for discharging a cooling gas toward the glass sheet conveying path is continuously arranged on both sides through the conveying path; and a glass that passes through the heating furnace and reaches the quenching device. It is a manufacturing apparatus of a bending-strengthened glass sheet provided with a conveying means having a curvature in a direction substantially perpendicular to a glass sheet conveying direction, which conveys a sheet, wherein a position of a most upstream end of the cooling gas spraying means in a glass sheet conveying direction is set. It is characterized in that it is different on both sides of the transport path.

[0013] By adopting such an apparatus, it is possible to easily improve the degree of freedom of molding simply without adding a new gas blowing means to the conventionally used heating furnace and rapid cooling apparatus. An apparatus for producing a bending-strengthened glass sheet can be obtained. That is, according to the apparatus of the present invention, one of the surfaces of the glass sheet conveyed by the conveying means is cooled first in the quenching device.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a sectional view showing an example of an apparatus for carrying out the method for bending and strengthening a glass sheet of the present invention. An air table 11 is provided in the heating furnace 1 as a means for transporting a glass plate. This air table 11
Has a large number of nozzle holes, and heated air blown out from the nozzle holes blows out to the lower surface of the glass plate to convey while supporting the glass plate. The hot air plays a role of transporting the glass plate while floating, and a role of heating and softening the glass plate. In the heating furnace 1, the glass plate is heated and deformed by its own weight so as to conform to the surface shape of the air table, and has a certain curvature.

The air table 11 typically has a curvature in the direction perpendicular to the glass sheet transport direction and has a shape that is upwardly convex, but has a shape that is downwardly convex. Alternatively, if the target tempered glass is flat, the tempered glass may be flat. Further, a roll or the like may be used in place of the air table 11 as a transporting means for the glass plate.

One of the features of this apparatus is that a heating furnace 1 and a quenching apparatus 2 are disposed adjacent to each other because a press mold for forming the softened glass by sandwiching the softened glass is not required. From the viewpoint of improving the strength of
The heating furnace 1 and the quenching device 2 are arranged as close as possible.

A plurality of quench modules 21 and 22 are arranged from above and below toward the glass sheet conveying path inside the quenching device 2 installed adjacent to the heating furnace 1 and on the downstream side of the conveying. The glass sheet is strengthened while being conveyed by the cooling gas (typically, cooling air) supplied from the quench modules 21 and 22. Note that the quench modules 21 and 22 are not limited to the shape shown in FIG.

As shown in FIG. 1, in the first embodiment, the quench module 22 in the upper part of the glass sheet conveying path is used.
Is provided so as to retreat downstream of the quench module 21 at the lower part of the glass sheet transfer path in the glass sheet transfer direction.
That is, the most upstream end of the module below the transfer path is located upstream of the upstream end of the module above the transfer furnace in the transfer direction.

Usually, in order to improve the productivity, a plurality of glass sheets are continuously supplied to a strengthening device, each of which is continuously heated and bent in a heating furnace 1, and a quenching device is heated from the heating furnace 1. 2 and is quenched and strengthened in the quenching device 2. Usually, a cooling gas is continuously discharged in the quenching device 2 in order to cope with a glass plate that is continuously conveyed. Also in the apparatus shown in FIG. 1, the cooling gas from the quench modules 21 and 22 is continuously discharged.

Therefore, while the glass sheet carried out of the heating furnace 1 is further conveyed through the quenching device 2, cooling of only the lower surface of the glass sheet is started by the cooling gas discharged upward from the quench module 21, and then the cooling is started. Then, cooling of the upper surface by the cooling gas discharged downward from the quench module 22 is started, and the upper and lower surfaces are rapidly cooled to become a strengthened glass plate.

As described above, since the cooling start timing is shifted between the upper surface and the lower surface of the glass plate, the contraction rate of the surface of the glass plate is different between the upper and lower surfaces, and the glass plate is carried out of the heating furnace. The shape (shape formed by following the shape of the air table 11) is slightly different from the shape when the air table 11 is formed. For example,
In the case where the glass plate is formed so as to be convex upward, and when the cooling of the lower surface of the glass is advanced as shown in FIG. 1, the shape of the glass plate is larger than the shape when the glass plate is unloaded from the heating furnace. Also becomes a state of shallow bending. In this way, by making the cooling start timing different between the upper and lower surfaces of the glass, the degree of freedom in forming the glass plate can be increased.

The temperature of the glass sheet when leaving the furnace from the heating furnace is preferably a temperature near the softening point of the glass sheet. Then, the cooling gas is blown only to one surface of the glass plate, so that the temperature of this surface decreases earlier than the temperature of the other surface, and the cooling gas is blown to the other surface. Prior to this, the temperature preferably falls below the softening point of the glass sheet, more preferably below the strain point of the glass sheet. The temperature of the glass sheet when leaving the furnace from the heating furnace is more preferably not less than the strain point and not more than the softening point of the glass sheet.

Further, the apparatus shown in FIG. 1 is provided with a ring roller 3 above the glass transport path. This ring-roller 3 has a glass plate that has been conveyed,
It serves to prevent the cooling gas blown only from the quench module 21 from being excessively lifted upward. The glass plate is stably conveyed by the ring roller 3 without a great change in posture. The ring roller 3 effectively functions when one of the quench modules is retracted by a certain distance or more, but this distance is affected by the weight of the glass plate to be conveyed, the conveyance speed, and the like. In the case of general automotive side glass, the cooling distance with only one quench module is 4
When the distance exceeds 0 mm, it is preferable to install the ring roller 3.

As a means for supporting the surface of the glass plate, the above-described ring roller is a simple means, but is not limited thereto, and may be a heated gas (hot air) or the like.

When using supporting means such as rollers,
As shown in FIG. 1, it is preferable that this support means is installed at a position facing the quench module installed at the most upstream side of the glass transport path. This is because it is effective for keeping the glass plate in a good conveying posture. However, the support means such as rollers are not limited to a single installation as shown in FIG. 1, and a plurality of support means may be installed as needed.

In the apparatus shown in FIG. 1, in order to carry out the method of the present invention, the quenching device above the glass sheet conveying path is retracted to the downstream side of the glass sheet conveying. Alternatively, the cooling gas may not be discharged by, for example, filling the quench module 22 located at a fixed distance from the upstream end of the conveyance. (Second Embodiment) The apparatus shown in FIG. 2 is different from the apparatus shown in FIG. 1 in that the quenching device below the glass sheet conveyance path is retracted to the conveyance downstream side. By
The upper surface of the glass sheet discharged from the heating furnace is cooled first.

If this apparatus is used to cool the upper surface of the glass plate in advance, for example, when the glass plate is formed to be convex upward, the shape of the glass plate is carried out of the heating furnace. It can be in a state of deep bending than the shape when it is bent.

[0028]

As described above, according to the method for producing a bending-strengthened glass of the present invention, the cooling gas is blown before any one of the surfaces of the glass plate to utilize its own weight. The degree of freedom in forming a tempered glass plate to be bent and formed by bending can be easily and effectively improved.
Further, the apparatus for producing a bending-strengthened glass of the present invention is suitable as an apparatus for performing the above method.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating an example of an apparatus for performing a method for bending and strengthening a glass sheet according to the present invention.

FIG. 2 is a cross-sectional view schematically illustrating another example of an apparatus for performing the method for bending and strengthening a glass sheet of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Quench device 11 Air bed 12 Hot air 21, 22 Quench module G Glass plate

Claims (4)

[Claims] 1. A glass sheet is heated while being passed through a heating furnace, and is bent and formed by utilizing the weight of the glass sheet. Cooling gas is supplied to both sides of the glass sheet in a quenching device continuously disposed in the heating furnace. A method for producing a bending-strengthened glass sheet, wherein the cooling gas is sprayed prior to any one surface of the glass sheet. 2. The cooling gas is blown while supporting the other surface of the glass plate when the cooling gas is blown before any one surface of the glass plate.
4. The method for producing a bent tempered glass sheet according to item 1. 3. The cooling gas is blown onto one of the surfaces of the glass plate in advance, so that the temperature of the surface is reduced before the cooling gas is blown on the other surface of the glass plate. The method for producing a bent tempered glass sheet according to claim 1, wherein the softening point is not higher than the softening point of the sheet. 4. A heating furnace for heating a glass plate, and a cooling gas blowing means having a glass plate carrying-in port adjacent to the glass plate carrying-out port of the heating furnace and discharging a cooling gas toward the glass plate carrying path. A quenching device arranged continuously on both sides via the conveyance path, and a conveyance unit having a curvature in a direction substantially perpendicular to the glass sheet conveyance direction, for conveying the glass sheet to the quenching device through the heating furnace. A manufacturing apparatus for a bent-strengthened glass sheet, comprising: a position of a most upstream end of the cooling gas spraying means in a glass sheet transfer direction on both sides of the transfer path. apparatus.