JPH0137336B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a tempered glass used as an automobile window glass, and a method and apparatus for manufacturing the tempered glass. Generally, it is mandatory to use tempered glass for automobile windshields, and in order to manufacture this tempered glass, as shown in FIG. A large number of equal air jet nozzles 101 are installed facing each other, and a glass plate heated to a temperature close to the softening point is inserted between these air supply bodies 100, and air is emitted from the nozzles. A compressive stress layer is formed on the surface of the glass plate by rapidly cooling it by spraying cooling air onto the surface of the glass plate. The conventional tempered glass thus obtained has some perspective distortion. This perspective distortion is more likely to occur as the temperature of the glass at the start of quenching is higher. Therefore, to reduce perspective distortion, it is necessary to lower the glass temperature at the start of cooling as much as possible, and to improve the strength of tempered glass, it is necessary to cool it as quickly as possible. I have to increase my power. However, when using the air supply body 100 in which a large number of air jet nozzles 101 are evenly planted at approximately equal distances from the glass plate surface, the temperature of the glass is lowered at the start of quenching, and If the speed is increased, the glass plate is likely to crack due to quenching, and if the quenching rate is decreased to prevent this, the necessary degree of strengthening cannot be obtained. The present inventor focused on the fact that cooling cracks occur at the peripheral edge of a glass plate, where the strength is weakest, and by cooling the peripheral edge more uniformly than the center, the above-mentioned drawbacks were overcome. However, we succeeded in obtaining tempered glass with low perspective distortion and excellent strength. The object of the present invention is to have low perspective distortion and excellent strength, and to reduce glass cracking during rapid cooling as much as possible, thereby providing sufficient strength even for thin glass that is prone to cooling cracks. It is an object of the present invention to provide a tempered glass that can be tempered, a method for manufacturing the same, and a manufacturing device for the same. In order to achieve such an object, the tempered glass according to the first invention is characterized in that at least a part of the peripheral edge of the surface of the heated glass plate that is rapidly cooled by the cooling air jetted from the nozzle is smaller than the central part. The second aspect of the method for manufacturing tempered glass includes inserting a heated glass plate between a pair of air supply bodies having nozzles on opposing surfaces. , when blowing air from the nozzle onto the surface of the glass plate while causing the air supply body to perform an oscillation operation, widening the distance between a part of the peripheral edge of the glass plate and the nozzle facing this part; , the gist is that a part of the peripheral edge of the glass plate is cooled more uniformly than other parts;
The tempered glass manufacturing apparatus according to the invention includes a plurality of cooling air jetting nozzles installed on opposing surfaces of a pair of air supply bodies that communicate with a pressurized air source and perform an oscillation operation, The gist is that the length of the nozzles provided on at least a part of the peripheral edge of is made shorter than the nozzle provided in the center, and that the nozzle density in the part where these short nozzles are provided is higher than in the center. There is. A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a side view of an apparatus for manufacturing tempered glass according to the present invention. In the figure, 1 and 1 are air supply bodies that are capable of oscillating, for example, about 40 mm in the vertical direction. 1, 1 has a substantially box shape, and the ends of flexible tubes 2, 2 connected to an unillustrated pressure source are fixed to the outer surfaces thereof. A large number of air jet nozzles 4 are provided on each of the opposing surfaces 3, 3 of the air supply bodies 1, 1.
are being planted. Among these nozzles 4..., the nozzles 4a... planted on the upper end 3a and lower end 3b of the opposing surfaces 3, 3...
The length of the nozzle 4b is shorter than that of the nozzle 4b installed in the central portion 3c of the opposing surface 3. As shown in Fig. 2, the nozzles 4b are arranged in a staggered manner with a horizontal interval a of 30 mm and a vertical interval b of 40 mm, and the nozzles 4a have a slightly smaller diameter than the nozzles 4b. The arrangement state of the nozzles 4b is
One more nozzle is provided between..., and as a result, the nozzle density at the upper end 3a and lower end 3b of the opposing surface 3 is twice that at the central part 3c. The width c of the portion where the nozzle density doubles depends on the magnitude of the oscillation operation, but is appropriately large enough to cool a width of about 5 mm to 25 mm at the peripheral edge of the glass plate. In the above process, as shown in FIG. 1, the glass plate 5 heated to around the softening point is held between the fixing devices 6 and placed between the opposing nozzles 4 in a suspended state, and the air supply body 1 , 1 are caused to perform a vertical oscillation operation, and air is ejected from the nozzles 4 to rapidly cool the surface of the glass plate 5. Then, the upper end 5a and lower end 5b of the glass plate 5
The distance ND between the surface of the glass plate 5 and the nozzles 4a is wider than the distance ND between the surface of the glass plate central portion 5c and the nozzles 4b.
5b is cooled more uniformly than other parts. As a result, the rate at which cooling cracks occur due to the tension acting on the peripheral edge of the glass plate 5 during cooling is greatly reduced. Further, since the density of the nozzles 4a is twice that of the nozzles 4b, the cooling power will not be insufficient even if the distance between the glass plate 5 and the nozzles 4a becomes wide. Note that if the dynamic pressure acting on the central portion 5c of the glass plate differs from the dynamic pressure acting on the peripheral edges 5a, 5b, the glass plate will swing during oscillation, so the nozzle density and ND will vary. It is necessary to combine them so that the pressure does not change. Next, the present invention and a conventional example will be compared based on specific experimental results. The sample glass used in the experiment was 497 mm in size.
x 835 mm, the peripheral edge was polished with a diamond wheel, horizontal cracks were completely removed, and the polishing wheel immediately after or just before the polishing wheel was replaced was not used. Also, as a representation of the characteristic value of the experimental results, 50% The quality of the results was judged based on the failure temperature, that is, the glass temperature at the start of air cooling, at which half of the approximately 30 samples developed cooling cracks.

[Table] As can be seen from the above experimental results, the biggest cause of cooling cracking is ND, that is, the distance between the glass surface and the nozzle. For example, sample No. 1, which is a conventional example, has a 50% failure temperature of 603°C, whereas sample No. 8, which is a conventional example, has a 50% failure temperature of 596.5°C, which is also 6.5°C. Temperature is dropping. As is clear from the above explanation and experimental results, in manufacturing tempered glass according to the present invention,
By cooling only the peripheral edge, where fractures tend to occur due to tension during cooling, more evenly than other parts, cracking during cooling can be minimized, and cooling can begin immediately. It is also possible to lower the temperature of the glass plate during heating, making it possible to obtain tempered glass with less perspective distortion. In addition, the lack of cooling power due to uniform cooling can be solved by increasing the nozzle density, and since only a portion of the nozzle density is increased, the blower capacity can remain the same. It has many advantages such as being able to obtain tempered glass with excellent strength at a low cost.

[Brief explanation of drawings]

The drawings show a preferred embodiment of the present invention, and FIG. 1 is a front view of the main parts of the tempered glass manufacturing apparatus according to the present invention, FIG. 2 is a side view showing the nozzle arrangement of the same apparatus, and FIG. FIG. 3 is a side view similar to FIG. 2 showing a conventional example. In the drawings, 1 is the air supply body, 3 is the opposing surface of the air supply body, 4, 4a, 4b are the nozzles, 5 is the glass plate, 5a, 5b are the peripheral edges of the glass plate, and 5c is the center of the glass plate. Department.

Claims (1)

[Scope of Claims] 1. In tempered glass obtained by rapidly cooling the surface of a heated glass plate with cooling air jetted from a nozzle, at least a part of the peripheral edge of the glass plate is smaller than the central part. Tempered glass is characterized by uniform cooling. 2 A heated glass plate is placed between a pair of air supply bodies equipped with nozzles for jetting cooling air on opposing surfaces, and air is jetted from the nozzles while causing the air supply bodies to perform an oscillation operation. ,
When rapidly cooling the glass surface, by increasing the distance between at least a part of the peripheral edge of the glass and the nozzle facing this part, it is possible to compare at least a part of the peripheral edge of the glass with other parts. A method for manufacturing tempered glass characterized by uniform cooling. 3 A large number of cooling air jetting nozzles are installed on opposing surfaces of a pair of air supply bodies that communicate with a pressurized air source and perform an oscillation operation, and among the many installed nozzles, near the peripheral end of the air supply body Reinforcement characterized by making at least a part of the nozzles provided in the central part shorter in length than the nozzles provided in the central part, and in which the nozzle density in the part provided with the short nozzles is higher than in the central part. Glass manufacturing equipment.