JP2012116692A - Method and apparatus for bending forming glass plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus capable of bending forming even a thin-wall glass plate to a shape precisely conforming to a curved shape of a forming surface of a forming mold as compared with the case of employing a conventional press method or self-weight method or their equivalent method.SOLUTION: A glass plate 2 held on a heat resistive sheet 4 is heated and softened; thereafter, when the glass plate 2 is bending formed by utilizing a forming surface 5a composed of a projecting curved surface formed on the surface of a forming mold 5, the softened glass plate 2 is covered and pressed on the forming surface 5a of the forming mold 5 from the front side by using the heat resistive sheet 4, and wrapped on the forming surface 5a by imparting a tensile force to the heat resistive sheet 4 such that the heat resistive sheet 4 is in a state of being bent from the front-side outer end 5aa toward the rear side of the forming mold 5.

Description

  The present invention relates to a method for bending a glass plate and a molding apparatus therefor, and more specifically, a glass plate heated and softened by using a mold having a convex curved surface and a heat-resistant sheet is bent into a required curved shape. The present invention relates to a technique for molding.

  As is well known, a glass plate having a curved shape has been used relatively frequently as a window glass for automobiles or buildings, or a light-transmitting glass for electronic parts. The plate is usually obtained by reheating a flat glass plate to the vicinity of the softening point and applying secondary forming.

  The method of forming the curved glass plate is roughly divided into a pressing method and a dead weight method, if representative ones are roughly classified. The press method is a method of press-molding a softened glass plate using a mold having a curved molding surface, while the self-weight method is a mold called a ring mold having an outer peripheral end portion. The placed glass plate is softened by heating and formed into a curved shape by deformation due to its own weight.

  As specific examples thereof, as described in Patent Documents 1 and 2, for example, the pressing method moves a mold having a molding surface having a convex curved surface and a mold having a molding surface having a concave curved surface. Further, the two molds are moved close to each other and press-molded in a state where a glass plate heated to near the softening point is interposed between the molding surfaces of both molds.

  In addition, as described in Patent Document 3, for example, the self-weight method is such that a glass plate cut into a predetermined size and shape is placed on a ring-shaped bending die provided in a heating furnace, and bending molding is performed. The glass plate is deformed by heating to a possible softening temperature, and is bent into a curved shape along the shape of the bending die.

  On the other hand, for example, in FIG. 4 of Patent Document 4, a support member comprising a flexible porous member 13 and a buffer member 12 covering the porous member 13 is formed on a molding surface comprising a downward convex curved surface. The structure which interposes between the upper type | mold (plunger) 7 which has this, and the lower type | mold 8 which supports the peripheral part of a supporting member from the downward direction is disclosed. When the glass plate 3 heated and softened is transported between the plunger 7 and the support member, the plunger 7 descends and presses the glass plate 3 from above the glass plate 3 toward the support member. 7 and the support surface of the support member, and the lower die 8 is in contact with the lower surface of the peripheral edge of the support member to support the support member during press molding.

Japanese Utility Model Publication No. 64-10042 JP-A 64-24034 JP-A-9-208244 Japanese Examined Patent Publication No. 46-41320 (Fig. 4)

  By the way, the press method disclosed in Patent Documents 1 and 2 is an appropriate technique for performing bending molding with a large curvature radius on a thick glass plate having a plate thickness exceeding 1.5 mm, for example. It can be said that it is impossible to accurately respond to a request to perform bending with a small radius of curvature on a thinner glass plate.

  That is, when the present inventors tried to heat-soften the thin glass plate and bend a curved glass plate having a small curvature radius and a deep depth by a press method, the molding surfaces of the upper mold and the lower mold were A curved glass plate having a shape matching the curved shape could not be obtained, and a curved glass plate having a larger radius of curvature than the curved shape of the molding surface was only obtained.

  The reason for this is that, since the glass plate is generally thin, the glass plate is sufficiently pressed and surely fixed to such an extent that the restoration characteristics disappear, such as insufficient stretching of the glass plate during pressing. It cannot be done, and when it is taken out of the mold due to this, it is presumed that it comes from the fact that a restoring force is generated in the glass plate once bent into the required curved shape and its curvature radius becomes large. . In particular, in the vicinity of the edge of the thin glass plate, there is a tendency for the pressing force to be insufficient during pressing, and a relatively large restoring force remains around the edge of the glass plate after bending. For this reason, it is presumed that a large factor is that the periphery of the edge is slightly returned to the original state.

  Moreover, about the dead weight method disclosed by patent document 3, since a press is not performed like said press method, when the glass plate is thin, at the time of the bending shaping | molding with the small curvature radius, according to the said press method It is considered that a greater restoring force than the case remains in the glass plate. For this reason, the curved glass plate that is finally obtained must have a larger radius of curvature than the planned curved shape as a result of the large return of the curved glass plate after molding. Can happen.

  Furthermore, in the method disclosed in Patent Document 4, the molding surface of the upper mold presses the heat-softened glass plate against a flexible support member, but the support member has its outer end ( The outer peripheral edge) is supported from below by the lower mold. Therefore, the support member substantially contributes to the bending of the glass plate in the inner region including the support portion by the lower mold. Moreover, since the tension acting on the support member has a direction along the curved shape of the molding surface of the upper mold over the entire region, this method is not significantly different from the above-mentioned pressing method after all. . Therefore, even with this method, when a thin glass plate is bent with a small radius of curvature, a restoring force remains due to insufficient pressing force particularly around the edge of the glass plate. As a result, there is a problem that the curved glass plate finally obtained has a larger radius of curvature than the curved shape of the molding surface of the upper mold.

  In view of the above circumstances, the present invention accurately matches the curved shape of the molding surface of the molding die, even when a thin glass plate is used, compared to the case where the conventional pressing method, the dead weight method, or a method based thereon is adopted. It is an object of the present invention to provide a method and an apparatus that can bend into a matched shape.

  The method according to the present invention, which was created to solve the above technical problem, utilizes a molding surface comprising a convex curved surface formed on the surface of a mold after heat-softening a glass plate held on a heat-resistant sheet. Then, in the glass plate bending method for bending the glass plate, the softened glass plate is covered with the heat-resistant sheet from the front side and pressed against the molding surface of the mold, and the heat-resistant sheet is It is characterized in that the glass plate is attached to the molding surface by applying tension to the heat-resistant sheet so as to be bent from the front-side outer end portion toward the back side.

  According to such a method, the heat-softened glass plate is covered from the front side with the heat-resistant sheet and pressed against the molding surface formed of the convex curved surface of the molding die. Under such conditions, the heat-resistant sheet moves from the front outer end of the mold toward the back side (strictly speaking, from the front outer end of the mold toward the back of the virtual extension surface of the molding surface). Tension is applied so as to be in a bent state. Therefore, even if the glass plate is thin and the curvature radius of the molding surface is small, the heat-resistant sheet wraps the molding die from the molding surface side even if the side surface portion has a sudden angle change from the central portion. In such a manner, the entire region from the central portion to the side surface portion of the glass plate can be pressed against the molding surface to be put together. In such a state, from the heat-resistant sheet, a sufficient pressing force acts over the entire region including the side surface portion and the periphery of the edge portion of the glass plate, so there is insufficient stretching around the edge portion. It becomes difficult to occur, and it is fixed to the planned curved shape in a state where the restoring force is surely lost. As a result, even if the glass plate finally obtained by bending is thin and has a small radius of curvature, the restoring force and return due to this do not occur, so the curved shape of the molding surface of the mold The shape is exactly matched. Therefore, it becomes possible to easily and reliably form various curved glass plates according to demands with a bending apparatus having a simple configuration, and in particular, it is possible to optimize the bending method for thin glass plates. Figured.

  In this case, it is preferable to further use another heat-resistant sheet interposed between the molding surface of the mold and the glass plate.

  In this way, the front and back surfaces of the glass plate are covered with the two heat-resistant sheets, so that the temperature of the front and back surfaces of the glass plate can be evenly dispersed during bending molding, Bending can be performed underneath, and a mold trace from the molding die is not attached to the back surface of the glass plate, so that a high-quality curved glass plate can be obtained.

  In the above method, the molding die may be disposed with the molding surface facing downward, and conversely, the molding die may be disposed with the molding surface facing upward. Good.

  In such a case, the mold can be kept stationary in any of the above arrangement modes. And when the molding die is in a stationary state, the glass plate can be bent by simply holding the glass plate with the heat-resistant sheet and moving the heat-resistant sheet up or down. Can be simplified or the number of parts can be reduced.

  In the above method, after the glass plate is attached to the molding surface of the molding die by applying tension to the heat-resistant sheet, the glass plate is opposed to the molding surface of the molding die. You may make it shape | mold by inserting | pinching between the shaping | molding surfaces of another shaping | molding die.

  In this way, the curved glass plate once bent by the tension of the heat-resistant sheet is subjected to finish molding by the pair of molds, so that a curved glass plate having a more precise curved surface is obtained. In addition, the temperature distribution on both the front and back surfaces can be made more uniform, and abnormal deformation such as warpage can be corrected. In addition, when performing finish shaping | molding with a pair of shaping | molding die, it is preferable to cover the front and back both surfaces of a curved glass plate with a heat resistant sheet. Further, the other mold is not limited to a mold having a molding surface formed of a concave curved surface continuous from the center portion to the edge portion, and may be a ring mold having a molding surface only at the edge portion, for example.

  Examples of the heat-resistant sheet used in the above method include woven fabric or felt made of aramid fiber, glass fiber, silica fiber, metal fiber, ceramic fiber, or a mixture thereof.

  Such a heat-resistant sheet is sufficient in terms of heat resistance as well as strength and flexibility.

  In the above method, when the plate thickness of the glass plate is 1.5 mm or less, the above-described useful effect is exhibited.

  In addition, if the plate | board thickness of a glass plate is 0.8 mm or less, a bigger effect will be exhibited, and if it is 0.2 mm or less, a curved glass plate with a deeper depth will be appropriate using the softness | flexibility. Further effects such as being able to be manufactured can be exhibited.

  On the other hand, an apparatus according to the present invention, which was created to solve the above technical problem, has a glass plate that is held by a heat-resistant sheet and softened by heating, and has a molding surface formed of a convex curved surface formed on the surface of a molding die. In a glass sheet bending apparatus configured to bend and utilize, a gripping means for gripping an outer end portion of the heat-resistant sheet is disposed, and the softened glass sheet is disposed on a molding surface of the mold. Covering and pressing from the front side with the heat-resistant sheet, and applying the tensile force to the heat-resistant sheet so that the heat-resistant sheet is bent from the front-side outer end of the mold toward the back side The glass plate is characterized in that it is configured to cling to the molding surface.

  Among the configurations of this apparatus, in order to apply tension (tensile force) to the heat-resistant sheet, the configuration other than the point that the gripping means for gripping the outer end portion of the heat-resistant sheet is disposed in the present invention described above. Since the configuration of the method described at the beginning of the method is substantially the same, the explanation items including the operational effects are substantially the same as the explanation items already described for the method.

  As described above, according to the present invention, the heat-resistant sheet presses the entire region from the center portion to the side surface portion of the glass plate being heated and softened against the molding surface in such a manner that the mold is wrapped from the molding surface side. Since the heat-resistant sheet is in a state of being glued together, a large pressing force acts on the entire area of the glass plate, and insufficient stretching or the like hardly occurs around the edge portion. Thereby, since the said glass plate will be fixed in the state in which the restoring force disappeared appropriately, even if the glass plate finally obtained by bending is thin and has a small curvature radius A shape that exactly matches the curved shape of the molding surface of the mold.

1 (a), (b), and (c) are respectively schematic longitudinal front views showing the entire configuration of a glass sheet bending apparatus (implementation status of the bending method) according to the first embodiment of the present invention. is there. 2 (a), (b), and (c) are respectively schematic longitudinal front views showing the entire configuration of a glass sheet bending apparatus (implementation status of the bending method) according to the second embodiment of the present invention. is there. 3 (a) and 3 (b) are schematic longitudinal sectional front views showing the overall configuration of a glass sheet bending apparatus (implementation status of the bending method) according to the third embodiment of the present invention. 4 (a) and 4 (b) are schematic longitudinal front views showing the overall configuration of a glass sheet bending apparatus (implementation status of the bending method) according to the fourth embodiment of the present invention. 5 (a) and 5 (b) are schematic longitudinal sectional front views showing the overall configuration of a glass sheet bending apparatus (implementation status of the bending method) according to the fifth embodiment of the present invention. It is a schematic front view for demonstrating Example 1 of this invention. It is the schematic for demonstrating Example 2 of this invention.

  Hereinafter, a glass sheet bending method and apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the following embodiments, a glass plate having a plate thickness of 0.2 mm or less is a molding target.

  1A to 1C illustrate a bending apparatus 1 (implementation status of a bending method) according to the first embodiment of the present invention. As shown in FIG. 1A, the bending apparatus 1 includes, as main components, a first heat-resistant sheet 3 on which a glass plate 2 as a molding object is placed, and a first heat-resistant sheet 3 that covers the upper side of the glass plate 2. 2 It has the heat-resistant sheet 4 and the single shaping | molding die 5 by which the molding surface 5a which is arrange | positioned under these heat-resistant sheets 3 and 4 and which consists of a convex curved surface was turned up.

  Each of the first heat-resistant sheet 3 and the second heat-resistant sheet 4 is composed of a woven fabric or felt made of aramid fiber, glass fiber, silica fiber, metal fiber, ceramic fiber, or a mixture thereof. Therefore, these heat resistant sheets 3 and 4 are excellent not only in heat resistance but also in strength and flexibility.

  The outer end portion (outer peripheral end portion) of the second heat-resistant sheet 4 is gripped by a plurality of gripping means 6 that apply a tensile force (tension) to the sheet 4. The gripping means 6 can also be configured by a single member that surrounds and grips the outer periphery of the second heat-resistant sheet 4, and is configured by, for example, a pair of members that grip both ends in the left-right direction. You can also. Further, although not shown, the outer end portion (outer peripheral end portion) of the first heat-resistant sheet 3 is also gripped by gripping means having the same configuration, but the tension that causes the gripping means to act on the first heat-resistant sheet 3. The force may be different from the tensile force that the gripping means 6 acts on the second heat-resistant sheet 4.

  The mold 5 is accommodated in the heating furnace in a stationary state. In this embodiment, the molding surface 5a of the mold 5 is not only curved in the left-right direction in the figure, but is also curved in the front-rear direction (direction perpendicular to the paper surface). The outline shape in the plan view is a circle (including an ellipse) or a rectangle. Note that the molding surface 5a may be curved only in one direction.

  Next, the operation of the bending apparatus 1 having the above-described configuration (glass plate bending method) will be described.

  First, the glass plate 2 held by the first and second heat-resistant sheets 4 is put into a heating furnace in which the mold 5 is accommodated in a preheated state, as shown in FIG. In the state where the holding is performed, the mold 5 is spaced apart from the mold 5. Then, after the glass plate 2 is heated to the vicinity of the softening point, the first and second heat-resistant sheets 3 and 4 move downward, so that the glass plate 2 has the first heat-resistant property as shown in FIG. The sheet is pressed against the molding surface 5 a of the mold 5 through the sheet 3.

  In such a state, the second heat-resistant sheet 4 covering the glass plate 2 from the front side is behind the virtual extension surface 5ax of the molding surface 5a from the front side outer end portion (front side outer peripheral end portion) 5aa of the mold 5. The glass plate 2 is pulled by the gripping means 6 so that the glass plate 2 is bent toward the molding surface 5a. In other words, the second heat-resistant sheet 4 is an aspect that wraps the molding die 5 from the molding surface 5a side by the tension (or an aspect that wraps the molding surface 5a of the molding die 5). The region is pressed against the molding surface 5a to be in a state of clinging. In addition, about the 1st heat resistant sheet 3, it is maintained in the state closely_contact | adhered to the shaping | molding surface 5a in the state which does not produce distortion, such as a wrinkle, by being pulled by the holding means and giving tension | tensile_strength.

  Under such a state, the pressing force by the second heat-resistant sheet 4 acts sufficiently over the entire area of the glass plate 2, so that insufficient stretching or the like occurs around the edge of the softened glass plate 2. It becomes difficult. Therefore, the glass plate 2 is fixed to the planned curved shape in a state where the restoring force (internal restoring force) is surely disappeared over the entire area.

  At the time of this bending, the glass plate 2 is covered on both sides by the two heat-resistant sheets 3 and 4, so that the front and back temperatures of the glass plate 2 can be evenly dispersed, and the glass Since the mold trace from the molding surface 5a of the mold 5 is not attached to the back surface of the plate 2, the quality of the glass plate 2 can be improved.

  Thereafter, the glass plate 2 finally obtained by being carried out of the heating furnace and peeled off from the first and second heat-resistant sheets 4 is thin but has a restoring force and a return resulting therefrom. As a result, a curved shape that exactly matches the curved shape of the molding surface 5a of the mold 5 is obtained.

  As described above, after applying the tension to the second heat-resistant sheet 4 on the molding surface 5a of the molding die 5 and clinging the glass plate 2 in the heating furnace, as shown in FIG. As shown, it is preferable to perform final bending using another molding die 7 having a molding surface 7a formed of a concave curved surface corresponding to the molding surface 5a.

  In this way, the temperature distribution on both the front and back surfaces of the glass plate 2 can be made more uniform, abnormal deformation such as warpage can be corrected, and a glass plate having a more precise curved surface is finally obtained. The other mold 7 in this case may be a ring mold having a molding surface opposed to the outer peripheral portion of the molding surface 5a.

  In the above description of the present embodiment, as a measure for changing from the state shown in FIG. 1A to the state shown in FIG. However, apart from this, the height of the gripping part of the first and second heat-resistant sheets 3 and 4 is held at a fixed position (the holding part can be moved in the horizontal direction). ) And the mold 5 is moved up, the same action can be performed. In addition, the mold 5 can be moved up, and the first and second heat-resistant sheets 3 and 4 can be moved down.

  2A to 2C illustrate a bending apparatus 1 (implementation status of the bending method) according to the second embodiment of the present invention. The bending apparatus 1 according to the second embodiment is different from that according to the first embodiment described above in that the glass plate 2 is mounted on the second heat-resistant sheet 4 having the gripping means 6 at the outer end. And the point where the molding die 5 with the molding surface 5a facing downward is arranged at a position spaced directly above the glass plate 2. Therefore, in the heating furnace, the first and second heat-resistant sheets 3 and 4 are moved up so that the state shown in FIG. 2A is changed to the state shown in FIG. As shown in FIG. 5C, the operational effect by performing bending bending of the finish using another molding die 7 having a molding surface 7a having a concave curved surface is obtained. This is the same as in the first embodiment described above. In addition, about the common component requirement of the bending apparatus 1 which concerns on this 2nd Embodiment, and the bending apparatus 1 which concerns on the above-mentioned 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In this case, in the bending apparatus 1 according to the second embodiment, the lower side is the front side of the mold 5 and the upper side is the back side of the mold 5. In the second embodiment, the first heat-resistant sheet 3 may be attached and fixed to the molding surface 5a in a state where no tension is applied to the first heat-resistant sheet 3 or wrinkles are generated. May not be provided.

  3A and 3B illustrate a bending apparatus 1 (implementation status of the bending method) according to the third embodiment of the present invention. The bending apparatus 1 according to the third embodiment is different from that according to the first embodiment described above in that the front and back surfaces of the glass plate 2 are covered as shown in FIG. 1, a ring-shaped mold 8 having a molding surface 8a having a concave curved surface corresponding to the periphery of the edge of the molding surface 5a of the molding die 5 is disposed at a position spaced above the second heat-resistant sheets 3 and 4. As shown in FIG. 2B, the ring-shaped mold 8 is formed after the first and second heat-resistant sheets 3 and 4 are moved down and the glass plate 2 is clung to the molding surface 5a of the molding die 5. Moves downward and presses the periphery of the edge of the glass plate 2. Therefore, in addition to the pressing force due to the tension of the second heat-resistant sheet 4, the pressing force by the ring-shaped mold 8 also acts around the edge of the glass plate 2. Thereby, the periphery of the edge part of the glass plate 2 is fixed in a state where the restoring force disappears more reliably. In addition, about the common component of the bending apparatus 1 which concerns on this 3rd Embodiment, and the bending apparatus 1 which concerns on the above-mentioned 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  4A and 4B illustrate a bending apparatus 1 (implementation state of the bending method) according to the fourth embodiment of the present invention. The bending apparatus 1 according to the fourth embodiment differs from that according to the third embodiment described above in that the glass plate 2 is mounted on the second heat-resistant sheet 4 having the gripping means 6 at the outer end. The ring with the molding surface 8a facing upwards at the point where the molding die 5 with the molding surface 5a facing downward is located at a position separated from the point placed directly above the glass plate 2 This is the point at which the mold 8 is arranged. Therefore, in the heating furnace, the first and second heat-resistant sheets 3 and 4 are moved up so that the state shown in FIG. 4A is changed to the state shown in FIG. The operation effect by moving the ring-shaped mold 8 upward after that is the same as in the third embodiment described above. In addition, about the common component of the bending apparatus 1 which concerns on this 4th Embodiment, and the bending apparatus 1 which concerns on the above-mentioned 3rd Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In this case, in the bending apparatus 1 according to the fourth embodiment, the lower side is the front side of the mold 5 and the upper side is the back side of the mold 5. In the fourth embodiment, the first heat-resistant sheet 3 may be attached to the molding surface 5a and fixed in a state where no tension is applied to the first heat-resistant sheet 3, or the first heat-resistant sheet 3 is fixed. 3 may not be provided.

  5A and 5B illustrate a bending apparatus 1 (implementation state of the bending method) according to the fifth embodiment of the present invention. The bending apparatus 1 according to the fifth embodiment is different from that according to the above embodiment in that the glass plate 2 is placed on the second heat-resistant sheet 4 as shown in FIG. In this state, as shown in FIG. 5B, the second heat-resistant sheet 4 is bent by the gripping means 6 so as to go around from the front outer end 5aa of the upper mold 5 to the back side, thereby applying tension. It is. And the molding surface 5a of the upper mold | type 5 in this 5th Embodiment is extended from the center part to the upper end of a side part (substantially vertical surface part). Accordingly, the tension of the second heat-resistant sheet 4 acts so as to press the periphery (substantially vertical surface portion) of the glass plate 2 against the upper end portion of the molding surface 5 a of the upper mold 5. Thereby, the 2nd heat resistant sheet 4 is the aspect which wraps the shaping | molding die 5 from the shaping | molding surface 5a side by the tension | tensile_strength (or the aspect which wraps the shaping | molding surface 5a of the shaping | molding die 5), and the whole area | region of the glass plate 2 Can be brought into a state of being pressed against the molding surface 5a. This is advantageous in obtaining a curved glass plate 2 having a deep depth. In addition, about the common component requirement of the bending apparatus 1 which concerns on this 5th Embodiment, and the bending apparatus 1 which concerns on each above-mentioned embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In the fifth embodiment, the first heat-resistant sheet 3 is not used, but the sheet 3 may be used.

  In the above embodiment, the glass plate 2 having a thickness of 0.2 mm or less is the object to be molded. However, even the glass plate 2 having a thickness of about 1.5 mm is suitably bent by the bending apparatus 1 according to the present invention. Can be done.

[Example 1]
As Example 1 of the present invention, the following specific method was tried. That is, the glass plate 2 is a non-alkali glass having a softening point of about 950 ° C. and a plate thickness of 0.1 mm, and the mold 5 is made of stainless steel, and As the first and second heat-resistant sheets 3 and 4, those woven with metal fibers were used. In this case, as shown in FIG. 6, the molding die 5 is only a lower mold in which the molding surface 5a made of a convex curved surface faces upward, and the convex curved surface of the molding surface 5a is a cylindrical curved surface having a curvature radius of 700 mm. It is said that.

  First, as indicated by a symbol A in FIG. 6, the glass plate 2 is preheated to about 500 ° C. and loaded onto the first heat-resistant sheet 3, and the upper portion is covered with the second heat-resistant sheet 4. Thus, as indicated by the symbol B in the figure, it is put into the heating furnace 9 and is arranged at a spaced position directly above the mold 5. Thereafter, the entire inside of the heating furnace 9 is heated to near the softening point, the mold 5 rises with the start of softening of the glass plate 2, and the glass plate 2 is received by the molding surface 5 a of the mold 5. Then, the first and second heat-resistant sheets 3 and 4 are lowered while the mold 5 is raised, so that the softened glass plate 2 is formed on the molding surface 5a of the mold 5 as indicated by reference numeral C in FIG. To come along.

  Further, the second heat-resistant sheet 4 covering the upper surface of the glass plate 2 presses the glass plate 2 so as to wrap the molding surface 5 a of the molding die 5, so that the glass plate 2 is molded by the molding die 5. The curved surface shape exactly matches the surface 5a. At this time, the glass plate 2 is fixed in a state in which no restoring force remains therein, so that the glass plate 2 finally obtained after being taken out from the heating furnace 9 is formed on the molding surface 5a of the molding die 5. A shape that matches the curved surface shape is maintained.

[Example 2]
As Example 2 of the present invention, the following specific method was tried. That is, the glass plate 2 is an alkali-free glass having a softening point of about 950 ° C. and a plate thickness of 0.2 mm, and the mold 5 is made of stainless steel, and As the first and second heat-resistant sheets 3 and 4, those woven with silica fibers were used. In this case, as shown in FIG. 7, the mold has a ring having a lower mold 5 in which a molding surface 5a made of a convex curved surface faces upward, and a molding surface 8a made of a concave curved surface along the molding surface 5a of the lower mold 5. The convex surface of the lower mold 5 is a cylindrical curved surface with a radius of curvature of 700 mm.

  First, as indicated by reference symbol A in FIG. 7, the glass plate 2 is preheated to about 500 ° C., loaded onto the first heat-resistant sheet 3, and the upper portion thereof is covered with the second heat-resistant sheet 4. Thus, as indicated by the symbol B in the figure, it is put into the heating furnace 9 and disposed in the gap between the upper mold 8 and the lower mold 5. Thereafter, the entire inside of the heating furnace 9 is heated to near the softening point, and the lower mold 5 rises with the start of softening of the glass plate 2, and the glass plate 2 is received by the molding surface 5 a of the lower mold 5. Then, the first and second heat-resistant sheets 3 and 4 are lowered while the lower die 5 is raised, so that the softened glass plate 2 is formed on the molding surface 5a of the lower die 5 as indicated by reference numeral C in FIG. To come along.

  Further, the second heat-resistant sheet 4 covering the upper surface of the glass plate 2 presses the glass plate 2 so as to wrap the molding surface 5 a of the lower mold 5, so that the glass plate 2 is molded into the lower mold 5. It becomes a state familiar with the curved surface shape of the surface 5a. Thereafter, the upper die 9 is lowered and the periphery of the edge of the glass plate 2 is pressed to complete the bending. At this time, the glass plate 2 is fixed in a state where no restoring force remains in the glass plate 2, so that the glass plate 2 finally taken out from the heating furnace 9 is formed on the molding surface 5 a of the lower mold 5. A shape that matches the curved surface shape is maintained.

DESCRIPTION OF SYMBOLS 1 Bending apparatus 2 Glass plate 3 Heat-resistant sheet (1st heat-resistant sheet)
4 Heat-resistant sheet (second heat-resistant sheet)
5 Mold (mold with a convex surface)
5a Molding surface (molding surface consisting of convex curved surface)
5aa Outer end portion 5ax of molding die Virtual extension surface 6 of molding surface Gripping means 7 Other molding die (molding die having a molding surface formed of a concave curved surface)
7a (Molding surface consisting of concave curved surface)
8 Ring-shaped mold 8a Molded surface made of a concave surface of the ring-shaped mold 9 Heating furnace

Claims (8)

In the glass plate bending method, after the glass plate held by the heat-resistant sheet is heated and softened, the glass plate is bent using a molding surface formed of a convex curved surface formed on the surface of the molding die.
The softened glass plate is covered with the heat-resistant sheet from the front side and pressed against the molding surface of the mold, and the heat-resistant sheet is bent from the front outer end of the mold toward the back side. A method of bending a glass plate, wherein the glass plate is attached to the molding surface by applying tension to the heat-resistant sheet.   The method for bending a glass plate according to claim 1, further comprising using another heat-resistant sheet interposed between the molding surface of the mold and the glass plate.   The glass plate bending method according to claim 1 or 2, wherein the forming die is arranged with a forming surface facing downward.   The method for bending a glass sheet according to claim 1 or 2, wherein the forming die is arranged with a forming surface facing upward.   After applying tension to the heat-resistant sheet and clinging the glass plate to the molding surface of the molding die, the glass plate is attached to the molding surface of the molding die and another molding die facing the molding plate. The method for bending a glass sheet according to any one of claims 1 to 4, wherein the glass sheet is formed by being sandwiched between the molding surfaces.   The glass sheet according to any one of claims 1 to 5, wherein the heat-resistant sheet is a woven fabric or felt made of aramid fiber, glass fiber, silica fiber, metal fiber, ceramic fiber, or a mixture thereof. Bending method.   The plate | board thickness of the said glass plate is 1.5 mm or less, The bending forming method of the glass plate in any one of Claims 1-6 characterized by the above-mentioned. In a glass plate bending apparatus configured to bend and mold a glass plate held by a heat-resistant sheet and softened by heating using a molding surface formed of a convex curved surface formed on the surface of a mold,
A gripping means for gripping the outer end portion of the heat-resistant sheet is disposed, and the softened glass plate is covered with the heat-resistant sheet from the front side and pressed against the molding surface of the mold, and the heat-resistant sheet is the mold. The glass plate is attached to the molding surface by the gripping means acting on the heat-resistant sheet so that the heat-resistant sheet is bent toward the back side from the outer end of the front side. A glass sheet bending apparatus characterized by the above.

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