JP2002241140A - Apparatus and method for bending glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for bending a glass plate with high accuracy and efficiency by using a simple structure. SOLUTION: The apparatus for bending the glass plate is provided with a die 2 which has a prescribed curvature along the rim of the glass plate, an auxiliary die 3 juxtaposed with at least a part of the rim of this die 2, and a vertical movement means 6 for raising the die 2 to a position higher than the auxiliary die 3. The die 2 is provided with a first forming surface (forming surface of a lateral side 2a) having a first curvature, and a second forming surface (forming surface of longitudinal side 2b) having a second curvature. The auxiliary die 3 has the same curvature as that of the first forming surface in the region along the first forming surface, and has the curvature smaller than that of the second forming surface in the region along the second forming surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending apparatus and a bending method for bending a glass sheet.

[0002]

2. Description of the Related Art As one method of forming curved glass such as window glass for automobiles (or a step before pressing), a forming die formed of a substantially rectangular or trapezoidal ring frame corresponding to the outer edge shape of window glass is used. There is a method in which a flat glass plate is placed on this mold, heated and softened in a heating furnace, and bent into a shape of the mold by its own weight bending.

When a curved glass for an automobile is manufactured by using such a mold, the four sides of a rectangular ring frame are curved. Therefore, when the degree of bending (curvature) is increased, wrinkles are formed at four corners. Are easily formed, or a reverse bending is caused by a bending action in a reverse direction.

As one method for coping with this, deformation is suppressed by locally heating the four corners of the glass. However, this method requires a local heater for heating the four corners. In addition, the heating structure in the furnace becomes complicated, which causes an increase in cost and a problem such as deterioration of optical quality of a locally heated portion.

On the other hand, in Japanese Patent No. 2888977, a horizontal linear auxiliary mold is provided side by side on the left and right curved vertical sides of a molding die to form a double structure. Receiving and bending by its own weight along the curvature of the horizontal side of the molding die, then dropping the auxiliary mold to receive the glass plates on the left and right vertical sides of the molding die, and forming a method of self-weight bending along its curvature is disclosed. ing.

[0006]

However, in the method described in the above-mentioned patent publication, the molding surface of the auxiliary mold is linear, and there is no common curved shape with the molding surface of the molding die. After bending the horizontal side with its own weight along the molding surface of the molding die while supporting it with the molding surface of the auxiliary mold, when transferring the vertical side of this glass plate from a linear auxiliary mold to a curved molding die, There is a possibility that misalignment occurs and the molding accuracy is reduced. In this case, since the auxiliary plate is dropped and the glass plate is transferred to the forming die, the displacement is more likely to occur due to vibration or the like due to the drop. In addition, since the right and left vertical weights are bent from the horizontal state after the horizontal weight is bent, the entire time is long and the productivity is reduced, and the deepest bending position in the center of the glass plate is difficult to stabilize. Affect.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned conventional technique, and has as its object to provide a glass sheet bending apparatus and a bending method capable of efficiently and accurately bending a glass sheet with a simple structure.

[0008]

According to the present invention, there is provided an apparatus for bending a glass sheet, the mold having a predetermined curvature along a periphery of the glass sheet. An auxiliary die provided side by side along at least a part of the periphery of the molding die; and elevating means for raising the molding die to a position higher than the auxiliary die, wherein the molding die has a first curved shape. And a second molding surface having a second curvature, wherein the auxiliary mold has the first molding surface
Glass having the same curvature as the first molding surface in a region along the molding surface of the above, and having a shallower curvature than the second molding surface in a region along the second molding surface. Provided is an apparatus for bending a plate.

According to this structure, the auxiliary mold having a shallow bent shape (curved) before reaching the final bent shape (curved) by the forming die is used, and the auxiliary mold is supported by the auxiliary mold while supporting the glass plate. The other parts are bent by their own weight to the final shape, and the auxiliary mold part is bent by their own weight to preliminarily form the glass sheet. Thereafter, the glass sheet is supported only by the forming die and can be bent to the final shape. By sequentially forming the glass sheet on the two-stage curved forming surface in this manner, a high-quality curved glass sheet can be obtained by bending a deeply curved glass sheet without difficulty.

In this case, when the glass plate is first supported by the auxiliary mold, the glass plate is also partially supported by the molding die. As a result, the transfer from the auxiliary die to the molding die after the completion of the preforming process is continuously and smoothly performed as it is, thereby preventing displacement and shortening the molding time.

[0011] By the preliminary molding using the auxiliary mold, the softened glass plate is brought into contact with the auxiliary mold having the same curved shape as the molding die and is adapted to the auxiliary mold. The state is supported by both. In this state, the forming die can be gradually raised by a simple elevating device such as a cylinder, and the glass plate can be slowly transferred to the forming die and bent into a final shape. Thereby, it is possible to efficiently and continuously perform the bending while maintaining sufficient positional accuracy, and it is possible to enhance the production efficiency.

When the softened glass sheet is transferred from the auxiliary mold to the molding die, it is desirable not to place the glass plate on the molding die at once but to slowly raise the molding die so as not to affect the quality. When the auxiliary mold is lowered instead of the mold, the auxiliary mold supporting the glass plate is not dropped and separated at a stroke. It is desirable to gradually lower the part so that it can be slowly placed on the mold while the other part is deformed under its own weight.

In the present invention, the method for bending a glass sheet using the above-described apparatus for bending a glass sheet may further include forming the auxiliary mold by adjusting the height of the forming surface of the forming die in regions where the forming surfaces have different curvatures. Arranging the auxiliary mold and the mold so as not to be higher than the surface height;
Placing the glass plate on the auxiliary mold and the mold, heating and softening the glass plate, and adapting the glass plate to the auxiliary mold and the mold with its own weight; Raising the position of the molding die to support the glass plate only with the molding die, and adapting the glass plate to the molding die by its own weight by heating. Provide a way.

According to this structure, the preliminary self-weight bending is once performed by the auxiliary die using the bending device of the present invention, and then the bending is gradually transferred to the final shape forming die.
As described above, it is possible to bend continuously and efficiently while maintaining sufficient positional accuracy, so that a high-quality curved glass plate can be obtained and production efficiency can be increased.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a glass sheet bending apparatus according to an embodiment of the present invention.

The bending apparatus 1 includes a substantially rectangular (or trapezoidal) frame-shaped forming die 2 having a horizontal side 2a and a vertical side 2b corresponding to the shape of a window glass for an automobile to be formed when viewed from above. And a substantially U-shaped auxiliary mold 3 provided adjacent to the vertical sides 2b on both sides of the molding die 2. The upper edge (molding surface) of each horizontal side 2a and vertical side 2b of the molding die 2 is curved with a degree of bending corresponding to the final shape to be molded. Vertical side 2b
The degree of curvature of the molding surface of the auxiliary mold 3 in a portion parallel to the above is smaller than the degree of curvature of the molding surface of the molding die 2. The degree of curvature of the molding surface of the auxiliary mold 3 at the portion corresponding to the lateral side 2a is the same as the degree of curvature of the molding surface of the molding die 2.

Each auxiliary mold 3 is fixed to an outer frame 4. The molding die 2 is fixed to an inner frame 5 arranged inside the outer frame 4 so as to be able to move up and down. The inner frame 5 is driven by an air cylinder 6 via a pressing piece 8, and moves up and down along a plurality of guide members (not shown) provided at appropriate positions. Air cylinder 6
Is connected to an air tube (not shown) and is driven by a solenoid valve 7. The outer frame 4 is provided with a plurality of holding mechanisms 9 (only one is shown in the figure) for holding the inner frame 5 at a raised position.

As shown in FIG. 2, for example, the holding mechanism 9 has a support piece 12 fixed to the outer frame 4, a support piece 13 is pivotally mounted on the support piece 12, and the support piece 13 is engaged with the support piece 13. Stop piece 1
5 is fixed to the inner frame 5 side. When the inner frame 5 rises in the direction of arrow C, the locking piece 15 pushes up the receiving piece 13 and rotates it in the direction of arrow D. When it gets over this, the receiving piece 13 returns and is supported by the stopper 14. As a result, the locking piece 15 is placed thereon (indicated by the dashed line) to hold the inner frame 5 at the raised position.

The lifting means includes an air cylinder 6
Instead, a combination of a motor and a link mechanism, a feed screw mechanism, or the like may be used.

Both ends of the molding surface of the vertical side 2b of the molding die 2
In the lower position shown in FIG. 1 (the state before the molding operation), the height of the molding surface of the auxiliary mold 3 parallel to the outside thereof coincides with that of the auxiliary mold 3, and both ends of the molding surface of the lateral side 2a are It is arranged in a state aligned with the molding surface. That is, in a region where the curvatures of the molding surfaces are different from each other, the height of the molding surface of the molding die does not become higher than the height of the molding surface of the auxiliary die. In this state, a flat glass plate (not shown) to be formed is received at the four corners of the forming die 2 and both ends of the vertical side of the auxiliary die 3. In this state, the glass sheet is preformed as described later, and then the air cylinder 6
Is driven to gradually raise the forming die 2 as shown by the arrow A, and the glass plate is transferred to the forming die 2.

FIG. 3 shows an example of a heating furnace in which the above-mentioned glass sheet bending apparatus is used. The heating furnace 10 includes a conveyor 11 therein and a heater (not shown) on an inner wall thereof. A plurality of heating zones 10a to 10n are continuously provided in the heating furnace 10, and the above-described bending apparatus 1 in FIG. 1 is conveyed by a conveyor 11 in a direction of an arrow B and is heated in each heating zone for a predetermined time. . In the final heating zone 10n, the mold 2 of the bending apparatus 1 is lifted by the air cylinder 6, and the glass plate (not shown) is bent along the mold 2 into a final shape to be molded as described later. You. Thereafter, the glass sheet is cooled in the cooling zone 10r. This cooling may be slow cooling by natural cooling or rapid cooling by forced cooling using a fan or the like for obtaining a reinforcing effect. In addition, a configuration in which such a cooling zone is not provided inside the furnace and cooling is performed outside the furnace may be adopted.

Next, with reference to FIGS. 4 to 7, a description will be given of a forming method using the above-described glass sheet bending apparatus of the present invention. In each figure, (A) shows a side view as viewed from the vertical side, and (B) shows a side view as viewed from the horizontal side.

FIG. 4 is a diagram showing a state before the start of molding. As shown in the figure, the mold 2 and the auxiliary mold 3 are set at aligned positions, and a flat glass plate 16 is placed thereon. In this state, as shown in (A), both ends of the molding surface of the vertical side 2b of the molding die 2 and both ends of the molding surface of the auxiliary die 3 are aligned at the same height, and the glass plate 16 Mold 2
And the auxiliary mold 3 are supported at the ends of both molding surfaces. Further, as shown in (B), the side 2a of the molding die 2 and the auxiliary die 3 are in a state where the molding surfaces (upper edges) are aligned in parallel.
In this state, the glass plate 16 is heated and softened in a heating furnace to perform preliminary forming by its own weight bending.

FIG. 5 shows a state where the preforming is completed. (A)
As shown in the figure, on the vertical side, the softened glass plate 16
It is in contact with the molding surface of the auxiliary mold 3 and is familiar. Also,
As shown in (B), on the side, the glass plate 16 is brought into contact with the molding surface of the side 2a of the molding die 2 and is bent to its final shape by its own weight. At this time, the auxiliary type 3
It is also in contact with the molding surface of. From this state, the mold 2 is raised, and the glass plate 16 is moved from the auxiliary mold 3 to the mold 2.
Transfer to the top.

FIG. 6 shows an intermediate stage of the transfer. (A)
As shown in (2), when the forming die 2 is raised, the glass plate 16 is gradually moved from both ends to the vertical side 2b of the forming die 2 in a state where the softened glass plate 16 is in contact with the auxiliary die 3. Can be replaced. On the side 2a, the softened glass plate 16 is all supported on the side 2a of the mold 2 as shown in FIG.

FIG. 7 shows a state where molding is completed. In this state, as shown in (A) and (B), the entire glass plate 16 is supported only by the molding surface of the molding die 2 and is formed into a final shape by its own weight.

In the above description, an example in which a glass sheet is formed into a final shape only by its own weight has been described. However, a glass sheet lifted by a forming die may be pressed against a mold having a final shape.

[0028]

As described above, according to the present invention, an auxiliary mold having an intermediate stage of curvature before reaching a final bent shape is used, and the glass sheet is supported by the auxiliary mold and the other auxiliary mold is used. The glass sheet can be once preformed by bending the portion by its own weight to the final shape, and by bending the portion of the auxiliary mold by its own weight. Thereafter, the glass plate can be supported by only the forming die and bent to the final shape. By sequentially forming the glass sheet on the two-stage curved forming surface in this manner, a high-quality curved glass sheet can be obtained by bending a deeply curved glass sheet without difficulty.

In this case, when the glass sheet is first supported by the auxiliary mold, the glass sheet is partially supported by the forming die at the same time, so that the auxiliary mold is transferred from the auxiliary mold to the forming die after the completion of the preforming. Is performed continuously and smoothly as it is, thereby preventing displacement and shortening the molding time.

By this preforming, the softened glass plate also comes into contact with the auxiliary mold in the same curved portion as the forming die, so that the softened glass plate is partially supported by both the auxiliary mold and the forming die. Become. In this state, the forming die can be gradually raised by a simple elevating device such as an air cylinder, and the glass plate can be slowly transferred to the forming die and bent into a final shape. Thereby, it is possible to efficiently and continuously perform the bending while maintaining sufficient positional accuracy, and it is possible to enhance the production efficiency. Further, as compared with the case of using the horizontal auxiliary mold, the molding time as a whole can be reduced by the amount of the preliminary molding.

[Brief description of the drawings]

FIG. 1 is a perspective view of an essential part of a glass sheet bending apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration explanatory view of a holding mechanism of the bending apparatus of FIG. 1;

FIG. 3 is a configuration diagram of an example of a heating furnace to which the present invention is applied.

FIG. 4 is an explanatory view of a state before the start of forming by the glass sheet forming method of the present invention.

FIG. 5 is an explanatory view of a pre-forming end state following the state of FIG. 4;

FIG. 6 is an explanatory view of a state of transfer to a molding die following the state of FIG. 5;

FIG. 7 is an explanatory view of a molding end state following the state of FIG. 6;

[Explanation of symbols]

1: Bending apparatus, 2: Mold, 2a: Horizontal, 2b: Vertical, 3: Auxiliary, 4: Outer frame, 5: Inner frame, 6: Air cylinder, 7: Solenoid valve, 8: Pressing piece , 9: holding mechanism, 10: heating furnace, 10a to 10n: heating zone, 10r: cooling zone, 11: conveyor, 12: support piece, 13: receiving piece, 1
4: stopper, 15: locking piece, 16: glass plate.

Claims (2)

[Claims] 1. An apparatus for bending a glass plate, comprising: a forming die having a predetermined curvature along the periphery of the glass plate; and a juxtaposition along at least a part of the periphery of the forming die. An auxiliary mold; and an elevating means for elevating the mold to a position higher than the auxiliary mold. The mold has a first molding surface having a first curvature, and a second curvature. A second molding surface, wherein the auxiliary mold has a first molding surface in an area along the first molding surface.
A bending apparatus for bending a glass sheet, having the same curvature as the molding surface of (1), and having a curvature shallower than the second molding surface in a region along the second molding surface. 2. A method for bending a glass sheet using the apparatus for bending a glass sheet according to claim 1, wherein the height of the forming surface of the forming die is different in regions where the forming surfaces have different curvatures. Arranging the auxiliary die and the molding die side by side so as not to be higher than the height of the molding surface of the auxiliary die; placing the glass plate on the auxiliary die and the molding die; Heating and softening the plate, and adapting the glass plate to the auxiliary mold and the molding die by its own weight; elevating the position of the molding die to support the glass plate only with the molding die; Bending the glass sheet by its own weight into the forming die.