JPH03335B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Field of Application> The present invention relates to a method for manufacturing a tempered or semi-strengthened bent glass, and more specifically to a method for manufacturing a tempered or semi-strengthened bent glass having excellent dimensional accuracy and a desired curved shape useful for vehicle glass, etc. Concerning the manufacturing method. <Prior art> Compared to raw glass, tempered or semi-tempered glass has
Since it has 3 to 4 times the bending strength and 3 to 5 times the impact strength, it is often used as flat glass in fields that require high strength and impact resistance. Further, tempered or semi-tempered glass is used in some fields as so-called bent glass having a curved shape, for example, as window glass for vehicles. However, conventional tempered or semi-strengthened bent glass is limited in shape due to manufacturing problems described below, and has low curved surface precision.On the other hand, if curved surface precision is required, productivity is low, and it cannot fully meet market needs. It's hard to describe it as something. Therefore, this improvement is desired. The manufacture of tempered or semi-strengthened bent glass is generally carried out using a gravity method. This manufacturing method uses a mold with only an outer frame, and the curved surface is formed by deforming the heated raw glass sheet under its own weight. For this reason, the curved surface to be formed is limited to a suspended surface, and it is almost impossible to form any other curved surface shape. Furthermore, since the curved surface is formed only by deformation under its own weight, dimensional accuracy is poor and shape reproducibility is low. For example, conventional tempered or semi-strengthened bent glass can be
When laminated glass is made by stacking sheets of glass, bubbles often occur on the mating surfaces because the curved surfaces are different, and it rarely passes the perspective distortion and double image tests that are JIS test items. It's almost impossible. The present inventor has arrived at the present invention as a result of intensive research aimed at solving such problems. <Objective of the Invention> The first object of the present invention is to provide a method for manufacturing reinforced or semi-strengthened bent glass with excellent dimensional accuracy with high productivity. A second object of the present invention is to provide a method for manufacturing tempered or semi-strengthened bent glass having various curved shapes with excellent dimensional accuracy and high productivity. A third object of the present invention is to provide a tempered or semi-strengthened bent glass with excellent dimensional accuracy. A fourth object of the present invention is to provide a tempered or semi-strengthened bent glass useful as a raw material for laminated glass. Yet another object of the invention is to provide a tempered or semi-strengthened bent glass useful as vehicle glass. <Configuration of the Invention> The object of the present invention can be achieved by adopting the following configuration. A mold for producing reinforced or semi-strengthened bent glass using a self-weight method, which includes an outer frame that forms the outer shape of the bent glass, and a crosspiece having a large number of tooth shapes that form a predetermined curved surface shape on the inside of the outer frame. A raw glass plate was placed on the tooth mold and heated, and the raw glass was deformed by its own weight along the curved shape, and then the glass on the tooth mold was placed to match the curved shape of the glass. A method for manufacturing tempered or semi-strengthened bent glass, which is characterized by uniformly quenching and strengthening or semi-strengthening with air jetted from a number of nozzles. The present invention will be explained below with reference to the drawings. FIG. 1 is a schematic overview of one mold that can be used in the present invention. The mold 1 consists of an outer frame 2 and a crosspiece 3 provided inside the outer frame in the form of a fence, and when the upper edges of the outer frame 2 and the crosspiece 3 are connected, they form one curved surface. A tooth pattern is formed on the upper surface of this crosspiece 3. FIG. 2 is a diagram showing a state in which a mold 1 (shown in section A--A) is placed on a trolley 5, and a flat raw glass 4 is set thereon. As can be understood from these figures, the mold used in the present invention has a crosspiece for forming a desired curved shape inside the outer frame. The shape of this crosspiece may be, for example, a lattice shape (FIG. 3a) or a diamond shape (FIG. 3b) shown in FIG. 3, or other shapes. The crosspiece 3 has the function of regulating the curved shape of the glass plate, and at the same time has the function of not preventing the cooling air from uniformly cooling the glass when heat-bent glass is strengthened or semi-strengthened, in other words. The structure should minimize shadows, which are the parts that are not rapidly cooled. For this reason, it is necessary to reduce the contact area between the crosspiece and the glass and to prevent the flow of cooling air jetted from the nozzle from being obstructed. For this reason, in the present invention, a large number of tooth patterns are provided on the upper part of the crosspiece to reduce the contact area between the crosspiece and the glass, and at the same time, to prevent the flow of cooling air jetted from the nozzle from being obstructed (No. 4-1). figure)
In addition, the upper part of the crosspiece is made wave-like and a large number of teeth are provided thereon to disturb the flow of the ejected air and further improve the cooling efficiency (Fig. 4-2). If the flow of cooling air is obstructed by the crosspiece and a shadow is created, the glass in that area will not be cooled quickly, resulting in uneven cooling, resulting in so-called poorly tempered areas, which may crack during cooling. It may not show the required strength. As shown in FIG. 2, the flat raw glass 4 placed on the mold 1 is heated together with the mold 1 in a furnace.
By this heat treatment, the raw glass 4 is bent into the curved shape formed by the crosspiece 3 until it is supported by the upper edge of the crosspiece 3 under its own weight. This heat treatment can be performed, for example, under conventional heating conditions. When the raw glass 4 is bent along the curved shape formed by the frame 2 and the crosspiece 3, the bent glass 4' is placed on the mold 1 (part of the crosspiece 3 is shown in FIG. 5). The glass is rapidly cooled by cooling air 7 jetted from nozzles 6 provided above and below the glass, and becomes tempered or half-strengthened glass. It is preferable that a large number of air nozzles 6 are installed, such as in the shape of a sword mount, and in particular, it is preferable that the tips of the nozzles are arranged in accordance with the curved shape of the bent glass 4'.
Further, the nozzle 6 can be moved back and forth, left and right, or in a circular trajectory for the purpose of rapidly and uniformly cooling the glass surface. It may be moved to draw other trajectories. The diameter of the nozzle 6 may be determined depending on the temperature, thickness, degree of reinforcement, etc. of the glass.
For example, if the wind pressure is high and the air is rapidly cooled at a high wind speed, the nozzle diameter may be made small, and if the wind pressure is low and the air volume is large, the nozzle diameter may be made large. FIG. 6 is a diagram showing a reinforced or semi-strengthened bent glass 4' manufactured using the mold shown in FIG.
The shape of the periphery 8 of the bent glass 4' is formed in the shape of the outer frame 2, and the curved surface 9 shows the curved shape formed by the crosspieces 3. When the upper and lower cross sections of this bent glass 4' are taken, the curved surface is straight at the center and becomes curved as it goes left and right. This surface is the first
It has the same curved surface as mold 1 in the figure. FIG. 7 is an overview diagram schematically showing a conventional mold 1'. The mold 1' consists only of an outer frame 2' and does not have a crosspiece as in the case of the present invention. For this reason, the curved surface of the bent glass 4'' manufactured is a curved surface close to a suspended surface, but it is almost impossible to obtain a highly accurate curved shape.In other words, the bent glass 4'' manufactured using the conventional mold 1' is the circumference 1 of the glass as shown in Figure 8.
0 is formed into the shape of the outer frame 2', but since the curved surface 11 is formed only by its own weight, it almost has the shape of the outer frame combined with a catenary line. The vertical warpage δ shown in Fig. 8 is generally called "overlap" and is a typical characteristic, but it is almost impossible to control this overlap δ constant due to changes in the temperature distribution in the furnace, etc. Currently, each product has a different δ.
For this reason, for example, a variation in δ (for example, 0 to 20 mm) is allowed for a front window glass for an automobile. However, when making laminated glass using these, for example, by laminating two sheets of conventional tempered or semi-strengthened bent glass, it is almost impossible to make laminated glass that passes the JIS perspective distortion and double image tests. It is in. The semi-strengthened or tempered glass in the present invention is JIS
It satisfies the characteristics specified in R3206, R3211, and R3212. When looking at the state of residual stress in the bent glass manufactured by the present invention in a photoelastic test, it was found that the state of residual stress was due to the airflow of the nozzle that appears in general tempered or semi-strengthened glass, as shown in the basic schematic diagram in Figure 9. Wire mesh pattern 1
In addition to 3, a mark 14 of photoelastic distortion due to the tooth shape of the crosspiece can be seen. Note that the pattern of an actual photoelastic strain photograph is not necessarily as orderly as the schematic diagram because the air flow is disturbed by the shape of the crosspiece, the relative position of the tooth shape of the crosspiece and the nozzle, etc. Additionally, the difference between tempered glass and semi-tempered lath is the contrast between the shadows and bright areas of the pattern, with tempered glass being sharper. Furthermore, in the case of automobile front window glasses, the overlap δ is mostly distributed between 0 and 1 mm. Further, the dimensions and curvature of the curved surface can have an accuracy of ±0.5 or less with respect to the target dimensions and curvature. <Examples> The present invention will be further explained below with reference to Examples. Examples 1 and 2 A raw glass plate with a thickness of 3 mm, a height of about 700 mm, and a width of about 1400 mm was placed in a mold (position of bars: fence-like, shape of bars: 4th
Picture a, tooth pitch: 15mm, tooth size: 5
mm x 5 mm, spacing between bars: 100 to 200 mm), heated in a furnace, and deformed by its own weight. Next, the glass plate, which is bent along the curved shape of the mold, is taken out of the furnace.
Air was blown out from the nozzle (front and back distance of the nozzle: 40 mm, nozzle diameter: 2 mmφ, vertical distance of the nozzle: 180 mm) to rapidly cool the sample. The obtained front window glass for automobiles had an overlap δ between 0 and 1 mm, and other characteristics were as shown in the following table. This table also includes the furnace temperature and cooling air pressure.

[Table] <Effects of the Invention> According to the present invention, it is possible to manufacture a tempered or semi-strengthened bent glass with good dimensional accuracy and a desired shape and curved surface. It is possible to bond the sheets together with an adhesive or through a resin plate such as a polycarbonate resin plate. It is also possible to bond a heat-bent resin plate to a reinforced or semi-strengthened bent glass plate.

[Brief explanation of the drawing]

FIG. 1 is a schematic overview diagram showing one embodiment of the mold used in the present invention, FIG. 2 is an explanatory diagram showing the mold of the present invention (A-A sectional view) mounted on a trolley, and FIG. Figures a and b are explanatory diagrams showing the arrangement of the crosspieces, and Figures 4-1 and 4-2 are partial views of different crosspieces.
is a side view, b is a plan view, each c is X-X, Z-
A Z cross-sectional view, FIG. 5 is a partial explanatory diagram of the glass taken out from the furnace and air-cooled, FIG. 6 is a diagram showing an example of the bent glass of the present invention, and FIG. 7 is a diagram showing a conventional mold. A schematic overview diagram, FIG. 8 is a diagram showing an example of a conventional bent glass, and FIG. 9 is a basic schematic diagram of a photoelastic strain photograph. In the figure, 1 and 1' are molds, 2 and 2' are outer frames, 3 is crosspieces, 4 is flat raw glass, 4' and 4'' are bent glass, 5 is a trolley, 6 is an air nozzle, and 7 is a Air, 8 is around the glass, 9 is a curved surface of the glass, 10 is around the glass, 11 is a curved surface of the glass, 12 is a tooth pattern, 13
14 is a mark of photoelastic distortion caused by the crosspiece.

Claims (1)

[Claims] 1. A method for producing reinforced or semi-strengthened bent glass using a self-weight method, which includes an outer frame that forms the outer shape of the bent glass, and a metal plate provided with a crosspiece having a large number of teeth forming a predetermined curved shape on the inside of the outer frame. Using a mold, a raw glass plate is placed on the tooth mold and heated, the raw glass is deformed by its own weight along the curved shape, and then the glass on the tooth mold is set to match the curved shape of the glass. 1. A method for producing tempered or semi-strengthened bent glass, characterized in that the glass is strengthened or semi-strengthened by uniformly quenching it with air ejected from a large number of nozzles.