Bending device and bending method

Abstract

This bend molding apparatus comprises a gravity molding furnace, multiple carriers, a conveyor, an upper mold, a first elevating and lowering mechanism, a lower mold, a second elevating and lowering mechanism, and a sliding mechanism. The gravity molding furnace forms a press zone and a retreat zone inside thereof. Each of the multiple carriers includes a ring die that supports the peripheral edge of a glass plate from below. The second elevating and lowering mechanism: attaches and detaches the carriers to and from the conveyor in the retreat zone; and elevates and lowers the carriers detached from the conveyor in the retreat zone. The sliding mechanism: attaches and detaches the carriers to and from the conveyor in the press zone; and slides the carriers detached from the conveyor between the press zone and the retreat zone. The upper surface of the lower mold supports the whole lower surface of the glass plate when the glass plate is pressed by the upper mold from above.

Description

[Technical Field]

[0001] The present disclosure relates to a bending apparatus and a bending method. [Background technology]

[0002] The device described in Patent Document 1 simultaneously bends two overlapping glass sheets. The device includes a convex upper form and a concave lower form. The convex upper form generates an upward airflow to suction and hold the two glass sheets together. The convex upper form and the concave lower form have complementary shapes. The convex upper form is in the form of an annular frame that holds the periphery of the glass sheets.

[0003] The apparatus described in Patent Document 2 includes a contour mold. The contour mold includes a shaping rail that supports the peripheral edge of the glass sheet from below, and a chamber formed inside the shaping rail. A heated gas supply source supplies heated gas to the chamber, and the pressure of the heated gas presses the center of the glass sheet against the press surface of the upper mold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japan Special Publication No. 2008-526659 [Patent Document 2] Japan Special Publication No. 2006-519748 Summary of the Invention [Problem to be solved by the invention]

[0005] An apparatus for bending a glass sheet generally comprises a gravity forming furnace, a plurality of carriers, and a conveyor. The gravity forming furnace is divided into a plurality of zones. The plurality of carriers are arranged at intervals inside the gravity forming furnace. Each carrier includes a ring mold that supports the peripheral edge of the glass sheet from below. The conveyor intermittently moves the plurality of carriers together.

[0006] Known techniques for bending glass sheets include gravity forming and press forming. In gravity forming, a glass sheet is softened by heating and its edges are supported by a ring mold, allowing the glass sheet to bend under its own weight. In press forming, a mold is pressed against the glass sheet on the ring mold, transferring the shape of the mold to the glass sheet.

[0007] Bent glass sheets are used, for example, as automobile front windshields. In recent years, the functionality of front windshields has become more sophisticated, and there is a demand for glass sheets with high curved surface precision.

[0008] In gravity forming, the curved shape of the glass plate is controlled by controlling the temperature distribution of the glass plate. Therefore, the surface accuracy of the curved surface is low. In press forming, a mold is pressed against the glass plate on a ring mold, so the surface accuracy of the curved surface is low.

[0009] One aspect of the present disclosure provides a technique for improving the surface precision of a curved surface of a glass plate. [Means for solving the problem]

[0010] A bending apparatus according to one aspect of the present disclosure includes a gravity forming furnace, multiple carriers, a conveyor, an upper mold, a first lifting mechanism, a lower mold, a second lifting mechanism, and a slide mechanism. The gravity forming furnace defines a press zone and an evacuation zone therein. The multiple carriers are arranged at intervals inside the gravity forming furnace, and each includes a ring mold that supports the periphery of the glass sheet from below. The conveyor moves the multiple carriers together. The upper mold presses the glass sheet from above in the press zone. The first lifting mechanism raises and lowers the upper mold in the press zone. The lower mold supports the glass sheet from below in the press zone. The second lifting mechanism attaches and detaches the carrier to and from the conveyor in the evacuation zone, and raises and lowers the carrier removed from the conveyor in the evacuation zone. The slide mechanism attaches and detaches the carrier to and from the conveyor in the press zone, and slides the carrier detached from the conveyor between the press zone and the evacuation zone. The upper surface of the lower mold supports the entire lower surface of the glass sheet when the upper mold presses the glass sheet from above.

[0011] A bending apparatus according to another aspect of the present disclosure includes a gravity forming furnace, multiple carriers, a conveyor, an upper mold, a first lifting mechanism, a lower mold, and a second lifting mechanism. The gravity forming furnace defines a press zone therein. The multiple carriers are arranged at intervals inside the gravity forming furnace, and each includes a ring mold that supports the periphery of the glass sheet from below. The conveyor moves the multiple carriers together. The upper mold presses the glass sheet from above in the press zone. The first lifting mechanism raises and lowers the upper mold in the press zone. The lower mold supports the glass sheet from below in the press zone. The second lifting mechanism raises and lowers the lower mold in the press zone. The lower mold raises and lowers inside the ring mold of the carrier. The upper surface of the lower mold supports the center of the lower surface of the glass sheet when the upper mold presses the glass sheet from above. The glass sheet is supported from below by both the ring mold and the lower mold without being lifted from the ring mold. [Effects of the Invention]

[0012] According to one aspect of the present disclosure, the surface precision of the curved surface of the glass plate can be improved. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing a bending apparatus according to a first embodiment. [Figure 2] 2A and 2B are cross-sectional views showing an example of the operation of a bending forming device, where FIG. 2A is a cross-sectional view showing an example of S102 in FIG. 5, FIG. 2B is a cross-sectional view showing an example of S104 in FIG. 5, and FIG. 2C is a cross-sectional view showing an example of S105 in FIG. 5. [Figure 3] 3A and 3B are cross-sectional views showing an example of an operation subsequent to that shown in FIG. 2, where FIG. 3A is a cross-sectional view showing an example of S108 in FIG. 5, FIG. 3B is a cross-sectional view showing an example of S110 in FIG. 5, and FIG. 3C is a cross-sectional view showing an example of S111 in FIG. 5. [Figure 4] 4A and 4B are cross-sectional views showing an example of the operation subsequent to FIG. 3, where FIG. 4A is a cross-sectional view showing an example of S113 in FIG. 5, and FIG. 4B is a cross-sectional view showing an example of S114 in FIG. [Figure 5] FIG. 5 is a flowchart showing the bending method according to the first embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a bending apparatus according to the second embodiment. [Figure 7] 7A and 7B are cross-sectional views showing an example of the operation of a bending forming device, where FIG. 7A is a cross-sectional view showing an example of S302 in FIG. 8, FIG. 7B is a cross-sectional view showing an example of S303 in FIG. 8, FIG. 7C is a cross-sectional view showing an example of S304 in FIG. 8, and FIG. 7D is a cross-sectional view showing an example of S305 in FIG. 8. [Figure 8] FIG. 8 is a flowchart showing the bending method according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their description may be omitted. In addition, in Figures 1 and 6, the X-axis, Y-axis, and Z-axis directions are perpendicular to each other, the X-axis and Y-axis directions are horizontal, and the Z-axis direction is vertical.

[0015] (First embodiment) A bending apparatus 1 according to a first embodiment will be described with reference to FIG. 1. The bending apparatus 1 shown in FIG. 1 pre-bends two overlapping glass sheets 2 (only one sheet is shown in FIG. 1) simultaneously by gravity forming, and then simultaneously press-forms the two overlapping glass sheets 2. A release agent is applied between the two glass sheets 2 in advance. The release agent is removed after bending. The two glass sheets 2 are then bonded together via an interlayer film. As a result, laminated glass is obtained.

[0016] Laminated glass is used, for example, as the windshield of an automobile. In recent years, windshields have become increasingly sophisticated. For example, a head-up display (HUD) may project images onto the windshield. Also, devices such as cameras may be attached to the windshield. To reduce image distortion or improve the accuracy of device attachment, there is a demand for glass sheets 2 with high curved surface precision.

[0017] By simultaneously bending the two glass sheets 2 that make up the laminated glass, it is possible to match the surface precision of the two glass sheets 2. However, the bending device 1 may also bend the glass sheets 2 one by one. When bending the glass sheets 2 one by one, a release agent is naturally not required. Note that the laminated glass may be composed of three or more glass sheets.

[0018] The two glass sheets 2 constituting the laminated glass may have different thicknesses. The thickness of the glass sheet 2 on the vehicle exterior side is equal to or greater than the thickness of the glass sheet 2 on the vehicle interior side, and is preferably greater than the thickness of the glass sheet 2 on the vehicle interior side. The thickness of the glass sheet 2 on the vehicle exterior side is, for example, 1.1 mm to 3.0 mm. On the other hand, the thickness of the glass sheet 2 on the vehicle interior side is, for example, 0.5 mm to 2.3 mm.

[0019] When two glass sheets 2 of different thicknesses that make up laminated glass are bent and formed at the same time, a thinner glass sheet 2 is placed on top of a thicker glass sheet 2. By placing a glass sheet 2 with a lower bending rigidity on top of a glass sheet 2 with a higher bending rigidity, the surface precision of the two glass sheets 2 can be matched.

[0020] The glass sheets 2 may be provided with a solar control coating. The solar control coating is a heat reflective coating or a low-emissivity coating, preferably a low-emissivity coating. The solar control coating is provided on the main surface of the glass sheets 2 opposite the conveyor 25. The low-emissivity coating is preferably provided on the outermost recessed surfaces of the two glass sheets 2 that make up the laminated glass.

[0021] The low-emissivity coating may include a metal oxide layer. The metal may be at least one selected from tin, zinc, indium, tungsten, and molybdenum. The metal oxide may contain fluorine, chlorine, antimony, tin, aluminum, tantalum, niobium, indium, or gallium as a dopant. The low-emissivity coating may include an underlayer made of silicon oxide or silicon oxynitride. The low-emissivity coating may be a multilayer film including a metal layer and a pair of dielectric layers.

[0022] When the glass sheet 2 has a low-emissivity coating, cracks may appear in the low-emissivity coating after annealing in a bending device that uses gravity forming only. In contrast, it has been found that when a bending device uses press forming only, cracks do not appear in the low-emissivity coating after annealing, low emissivity is maintained, and reflection distortion does not worsen.

[0023] The glass plate 2 may be provided with a shielding print that forms a shielding band directly above the low-emissivity coating. The shielding print may be a black ceramic layer. When a shielding print is provided directly above the low-emissivity coating, a bending apparatus that only performs gravity forming may cause the shielding print and low-emissivity coating to crack and peel off after annealing. On the other hand, a bending apparatus that only performs press forming is expected to prevent cracks from occurring in the shielding print and low-emissivity coating after annealing, maintain low emissivity, and prevent deterioration of reflection distortion. Similarly, a bending apparatus 1 that performs press forming after gravity forming according to the present disclosure is expected to prevent cracks from occurring in the shielding print and low-emissivity coating, maintain low emissivity, and prevent deterioration of reflection distortion.

[0024] 1, the bending apparatus 1 includes, for example, a gravity forming furnace 10, a plurality of carriers 20, a conveyor 25, an upper mold 30, a first lifting mechanism 37, a lower mold 40, a second lifting mechanism 27, a slide mechanism 29, and a control unit 90. Each of the components will be described below.

[0025] The gravity forming furnace 10 forms multiple zones. The multiple zones are separated by insulating walls or the like. The multiple zones may have different lengths. Each zone is provided with a heat source (not shown). The heat source heats the glass sheet 2 placed on the carrier 20. The heat source heats the glass sheet 2 from both above and below. Alternatively, the heat source may heat the glass sheet 2 from the side.

[0026] The gravity forming furnace 10 has, for example, a pre-treatment zone Z1, a press zone Z2, an evacuation zone Z3, and a post-treatment zone Z4 formed therein in this order. The pre-treatment zone Z1 is a zone in which the glass sheet 2 is pre-bent by gravity forming on a ring mold 21 while being treated to have a temperature distribution that enables press forming of the glass sheet 2. The press zone Z2 is a zone in which the glass sheet 2 is press-formed between an upper mold 30 and a lower mold 40. The evacuation zone Z3 is a zone in which the carrier 20 is evacuated during press forming. The post-treatment zone Z4 is a zone in which the press-formed glass sheet 2 is annealed.

[0027] The multiple carriers 20 are arranged at intervals inside the gravity forming furnace 10. The intervals are, for example, equal. Each of the multiple carriers 20 includes a ring mold 21 that contacts the peripheral edge of the glass sheet 2 and supports the peripheral edge from below. The glass sheet 2 is heated and softened on the ring mold 21 in the pretreatment zone Z1. As a result, the glass sheet 2 is bent along the ring mold 21.

[0028] The ring mold 21 may be a single piece, or may be divided in the circumferential direction. In the latter case, the divided pieces constituting the ring mold 21 may be moved or rotated relative to one another to obtain a desired shape. Furthermore, the carrier 20 may include a plurality of ring molds 21 with partially different curvatures, and the ring molds 21 supporting the glass sheet 2 may be interchanged.

[0029] The conveyor 25 moves a plurality of carriers 20 together. Each of the plurality of carriers 20 can be attached to and detached from the conveyor 25. To remove a carrier 20 from the conveyor 25, the carrier 20 can be lifted from the conveyor 25. To attach a carrier 20 to the conveyor 25, the carrier 20 can be lowered onto the conveyor 25. The conveyor 25 moves a plurality of carriers 20 together intermittently.

[0030] The upper mold 30 presses the glass sheet 2 from above in the press zone Z2. The lower surface 31 of the upper mold 30 is a downwardly convex curved surface. The lower surface 31 of the upper mold 30 is approximately the same size as or larger than the upper surface of the glass sheet 2, and contacts and presses the entire upper surface of the glass sheet 2. This improves the surface precision of the upper surface of the glass sheet 2 compared to when pressing only a portion of the upper surface of the glass sheet 2.

[0031] The lower surface 31 of the upper mold 30 may be covered over substantially the entire surface with a cloth (not shown). The cloth may be a metal cloth, a glass cloth, or the like. The cloth is attached to the upper mold 30 with a hook or the like. The cloth prevents scratches on the glass plate 2 due to contact between the upper mold 30 and the glass plate 2. The cloth also covers the gas injection holes (described later) to prevent the outlines of the gas injection holes from being transferred to the glass plate 2.

[0032] The lower surface 31 of the upper mold 30 includes gas injection holes (not shown). The gas injection holes are arranged in a dispersed manner on the lower surface 31 of the upper mold 30. The gas injection holes inject gas such as air downward, and the injection pressure peels the glass sheet 2 from the upper mold 30. The peeled glass sheet 2 is placed on the carrier 20.

[0033] The lower surface 31 of the upper mold 30 does not necessarily have to have a gas suction hole. If a gas suction hole were present, the gas would be sucked through the gas suction hole, generating negative pressure on the lower surface 31 of the upper mold 30. The negative pressure would allow the glass sheet 2 to be sucked onto the upper mold 30. On the other hand, if there were no gas suction hole, the outline of the gas suction hole would not be transferred to the glass sheet 2.

[0034] The first lifting mechanism 37 raises and lowers the top mold 30 in the press zone Z2. The first lifting mechanism 37 is, for example, a hydraulic cylinder. The first lifting mechanism 37 lowers the top mold 30, causing the top mold 30 to press the glass sheet 2. The first lifting mechanism 37 also raises the top mold 30, causing the top mold 30 to move away from the movement path of the carrier 20.

[0035] The lower mold 40 supports the glass sheet 2 from below in the press zone Z2. The upper surface 41 of the lower mold 40 is a downwardly convex curved surface, i.e., a concave curved surface, similar to the lower surface 31 of the upper mold 30. When the upper mold 30 presses the glass sheet 2 from above, the upper surface 41 of the lower mold 40 comes into contact with and supports the entire lower surface of the glass sheet 2. Compared to when the ring die 21 supports only the peripheral edge of the lower surface of the glass sheet 2, the surface precision of the lower surface of the glass sheet 2 can be improved.

[0036] The upper surface 41 of the lower mold 40 may be covered over substantially the entire surface with a cloth (not shown). The cloth may be a metal cloth, a glass cloth, or the like. The cloth is attached to the lower mold 40 with a hook or the like. The cloth prevents the glass plate 2 from being scratched due to contact between the lower mold 40 and the glass plate 2.

[0037] The upper surface 41 of the lower mold 40 does not necessarily have to have a gas suction hole. If a gas suction hole is present, the gas suction hole will suck in gas, generating negative pressure on the upper surface 41 of the lower mold 40. The negative pressure will allow the glass sheet 2 to be sucked into the lower mold 40. On the other hand, if there is no gas suction hole, the outline of the gas suction hole will not be transferred to the glass sheet 2.

[0038] Incidentally, an upper mold 30 and a lower mold 40 are arranged in press zone Z2. The upper mold 30 is arranged above the movement path of the carrier 20, and the lower mold 40 is arranged below the movement path of the carrier 20. The upper mold 30 and the lower mold 40 sandwich and press the glass sheet 2.

[0039] Therefore, the bending apparatus 1 of this embodiment is provided with a second lifting mechanism 27 and a slide mechanism 29 to retract the carrier 20 from the press zone Z2 to the retraction zone Z3 before the glass sheet 2 is sandwiched and pressed between the upper mold 30 and the lower mold 40. As shown in Figure 3(A), if the carrier 20 is retracted in advance, the upper mold 30 can be inserted into the movement path of the carrier 20, and the glass sheet 2 can be sandwiched and pressed between the upper mold 30 and the lower mold 40.

[0040] The second lifting mechanism 27 attaches / detaches the carrier 20 to / from the conveyor 25 in the evacuation zone Z3. The second lifting mechanism 27 also raises / lowers the carrier 20 removed from the conveyor 25 in the evacuation zone Z3. The second lifting mechanism 27 removes the carrier 20 from the conveyor 25 by lifting the carrier 20 from the conveyor 25 in the evacuation zone Z3. Next, the second lifting mechanism 27 further raises the carrier 20, forming a space below the carrier 20 to receive another carrier 20. As a result, as shown in FIG. 2(C), the slide mechanism 29 can slide an empty carrier 20 below the carrier 20 lifted by the second lifting mechanism 27. An empty carrier 20 is a carrier 20 that does not carry a glass sheet 2.

[0041] The slide mechanism 29 attaches and detaches the carrier 20 to and from the conveyor 25 in the press zone Z2. The slide mechanism 29 also slides the carrier 20 removed from the conveyor 25 between the press zone Z2 and the evacuation zone Z3. Before sliding the carrier 20 horizontally, the slide mechanism 29 lifts and removes the carrier 20 from the conveyor 25. Then, the slide mechanism 29 slides the carrier 20 horizontally from the press zone Z2 to the evacuation zone Z3.

[0042] As shown in Figure 2(C), the carrier 20 is no longer present in the press zone Z2. Therefore, as shown in Figure 3(A), the upper mold 30 can enter the movement path of the carrier 20. As a result, the glass sheet 2 can be sandwiched and pressed between the upper mold 30 and the lower mold 40. After pressing, the slide mechanism 29 slides the carrier 20 horizontally from the evacuation zone Z3 to the press zone Z2. The slide mechanism 29 then lowers the carrier 20 onto the conveyor 25 and attaches it there.

[0043] As described above, in the press zone Z2, the lower mold 40 and the upper mold 30 sandwich and press the glass sheet 2. Therefore, the bending apparatus 1 may include an aspirator 32 so that the upper mold 30 can receive the glass sheet 2 from the carrier 20 before pressing the glass sheet 2. The aspirator 32 sucks the glass sheet 2 into the upper mold 30. The aspirator 32 is fixed to the upper mold 30, and is raised and lowered by a first lifting mechanism 37.

[0044] As shown in FIG. 1, the aspirator 32 includes a suction cover 34 that forms a ring-shaped slit 33 for sucking gas around the lower surface 31 of the upper mold 30. The slit 33 is connected to a suction source outside the gravity forming furnace 10 via a duct 35 or the like. As shown in FIG. 2(B), the slit 33 sucks gas below the upper mold 30, forming an ascending air current below the upper mold 30. The ascending air current allows the two overlapping glass sheets 2 to be sucked together into the upper mold 30.

[0045] When the aspirator 32 sucks the glass sheet 2 into the top mold 30, the bottom surface 31 of the top mold 30 does not need to have a gas suction hole. If there is a gas suction hole, the gas suction hole will suck in gas, generating negative pressure on the bottom surface 31 of the top mold 30. The negative pressure allows the glass sheet 2 to be sucked into the top mold 30. On the other hand, if there is no gas suction hole, the outline of the gas suction hole will not be transferred to the glass sheet 2.

[0046] The control unit 90 is, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores programs that control various processes executed in the bending apparatus 1. The control unit 90 controls the operation of the bending apparatus 1 by having the CPU 91 execute the programs stored in the storage medium 92.

[0047] Next, the operation of the bending apparatus 1 according to the first embodiment will be described with reference to FIGS. 1 to 5. A series of operations shown in FIGS. 1 to 5 is performed under the control of the control unit 90. First, the conveyor 25 moves a plurality of carriers 20 together (step S101). As a result, as shown in FIG. 1, one carrier 20 is placed in each of the press zone Z2 and the evacuation zone Z3. A glass sheet 2 is placed on the carrier 20.

[0048] Next, as shown in Fig. 2(A), the first lifting mechanism 37 lowers the top mold 30 until the bottom surface 31 of the top mold 30 approaches the glass sheet 2 to the extent that a small gap is formed between the top mold 30 and the glass sheet 2 (step S102). Next, the suction device 32 sucks the glass sheet 2 onto the top mold 30 (step S103). Next, as shown in Fig. 2(B), the first lifting mechanism 37 raises the glass sheet 2 together with the top mold 30 (step S104).

[0049] In steps S102 to S104, the glass sheet 2 is transferred from the carrier 20 to the upper mold 30. The glass sheet 2 is held by the upper mold 30 above the movement path of the carrier 20. While steps S102 to S104 are being performed in the press zone Z2, the second lifting mechanism 27 lifts the carrier 20 in the evacuation zone Z3 (step S201).

[0050] 2(A), the second lifting mechanism 27 removes the carrier 20 from the conveyor 25 by lifting the carrier 20 from the conveyor 25 in the evacuation zone Z3. Subsequently, the second lifting mechanism 27 further lifts the carrier 20 to form a space below the carrier 20 to receive another carrier 20. Step S201 may be performed after step S101 and before step S105.

[0051] 2(C), the slide mechanism 29 lifts and removes the carrier 20 from the conveyor 25 in the press zone Z2, and then slides the removed carrier 20 horizontally from the press zone Z2 to the evacuation zone Z3 (step S105). The slide mechanism 29 slides the empty carrier 20 below the carrier 20 previously lifted by the second lift mechanism 27.

[0052] As a result, in the evacuation zone Z3, two carriers 20 are lined up with a vertical gap between them. On the other hand, in the press zone Z2, the carrier 20 is no longer present, so the upper mold 30 can enter the movement path of the carrier 20.

[0053] Next, the first lifting mechanism 37 lowers the glass sheet 2 together with the upper mold 30 until the glass sheet 2 approaches the lower mold 40 to the extent that a slight gap is formed between the glass sheet 2 and the lower mold 40 (step S106). Subsequently, the suction device 32 releases the suction of the glass sheet 2 against the upper mold 30 (step S107). Next, as shown in FIG. 3(A), the first lifting mechanism 37 further lowers the upper mold 30, and the glass sheet 2 is sandwiched and pressed between the upper mold 30 and the lower mold 40 (step S108).

[0054] According to this embodiment, when the upper mold 30 and the lower mold 40 press the glass sheet 2, the suction device 32 releases the suction of the glass sheet 2 against the upper mold 30. This improves the adhesion between the two overlapping glass sheets 2 and allows the surface precision of the two glass sheets 2 to be matched. However, when the upper mold 30 and the lower mold 40 press the glass sheet 2, the suction device 32 does not have to release the suction of the glass sheet 2 against the upper mold 30.

[0055] Thereafter, the suction device 32 sucks the glass sheet 2 again onto the upper mold 30 (step S109). Next, the first lifting mechanism 37 raises the glass sheet 2 together with the upper mold 30 above the movement path of the carriers 20, as shown in Fig. 3(B) (step S110). A space is formed below the upper mold 30 into which the empty carriers 20 are returned.

[0056] 3(C), the slide mechanism 29 horizontally slides the empty carrier 20 from the evacuation zone Z3 to the press zone Z2 (step S111). Subsequently, the slide mechanism 29 lowers the empty carrier 20 onto the conveyor 25 and attaches it thereto.

[0057] Next, the first lifting mechanism 37 lowers the glass sheet 2 together with the upper mold 30, and places the glass sheet 2 on the carrier 20 (step S112). Subsequently, as shown in FIG. 4(A), the aspirator 32 releases the suction of the glass sheet 2 against the upper mold 30 (step S113). Here, gas injection holes on the lower surface 31 of the upper mold 30 may inject gas downward, and the injection pressure may peel the glass sheet 2 from the upper mold 30. Finally, the first lifting mechanism 37 raises the upper mold 30 above the movement path of the carrier 20, as shown in FIG. 4(B) (step S114).

[0058] In steps S112 to S114, the glass sheet 2 is transferred from the upper mold 30 to the carrier 20. While steps S112 to S114 are being performed in the press zone Z2, the second lifting mechanism 27 lowers the carrier 20 in the evacuation zone Z3 (step S202), as shown in FIG. 4(A). The second lifting mechanism 27 lowers the carrier 20 onto the conveyor 25 and attaches it. Step S202 may be performed between step S111 and the next step S101.

[0059] Thereafter, step S101 is performed again, and the press-formed glass sheet 2 is moved together with the carrier 20 from the press zone Z2 to the evacuation zone Z3. Thereafter, the glass sheet 2 together with the carrier 20 passes through the post-treatment zone Z4 and is finally taken out of the gravity forming furnace 10.

[0060] (Second embodiment) Next, a bending apparatus 1 according to a second embodiment will be described with reference to Fig. 6. The following mainly describes the differences between this embodiment and the first embodiment. As shown in Fig. 6, the bending apparatus 1 includes, for example, a gravity forming furnace 10, a plurality of carriers 20, a conveyor 25, an upper mold 30, a first lifting mechanism 37, a lower mold 40, a second lifting mechanism 47, and a control unit 90. Each component will be described below.

[0061] The gravity forming furnace 10 has, for example, a pre-treatment zone Z1, a press zone Z2, and a post-treatment zone Z4 formed therein in this order. Unlike the first embodiment, the gravity forming furnace 10 does not have an evacuation zone Z3 between the pre-treatment zone Z1 and the post-treatment zone Z4. In the pre-treatment zone Z1, the glass sheet 2 is heated and softened on the ring mold 21. As a result, the glass sheet 2 is bent along the ring mold 21.

[0062] The upper mold 30 presses the glass sheet 2 from above in the press zone Z2. The lower surface 31 of the upper mold 30 is a downwardly convex curved surface. The lower surface 31 of the upper mold 30 is approximately the same size as or larger than the upper surface of the glass sheet 2, and contacts and presses the entire upper surface of the glass sheet 2. This improves the surface precision of the upper surface of the glass sheet 2 compared to when pressing only a portion of the upper surface of the glass sheet 2.

[0063] The first lifting mechanism 37 raises and lowers the top mold 30 in the press zone Z2. The first lifting mechanism 37 is, for example, a hydraulic cylinder. The first lifting mechanism 37 lowers the top mold 30, causing the top mold 30 to press the glass sheet 2. The first lifting mechanism 37 also raises the top mold 30, causing the top mold 30 to move away from the movement path of the carrier 20.

[0064] The lower mold 40 supports the glass sheet 2 from below in the press zone Z2. The upper surface 41 of the lower mold 40 is a downwardly convex curved surface, i.e., a concave curved surface, similar to the lower surface 31 of the upper mold 30. When the upper mold 30 presses the glass sheet 2 from above, the upper surface 41 of the lower mold 40 comes into contact with and supports the center of the lower surface of the glass sheet 2. Compared to when the ring die 21 supports only the peripheral edge of the lower surface of the glass sheet 2, the surface precision of the center of the lower surface of the glass sheet 2 can be improved.

[0065] In this embodiment, similarly to the first embodiment, an upper mold 30 and a lower mold 40 are arranged in the press zone Z2. The upper mold 30 is arranged above the movement path of the carrier 20, and the lower mold 40 is arranged below the movement path of the carrier 20. The upper mold 30 and the lower mold 40 sandwich and press the glass sheet 2.

[0066] However, in this embodiment, unlike the first embodiment, the gravity forming furnace 10 does not form the evacuation zone Z3 between the pre-treatment zone Z1 and the post-treatment zone Z4. Therefore, the carrier 20 cannot be evacuated from the press zone Z2 to the evacuation zone Z3.

[0067] Therefore, in this embodiment, the upper surface 41 of the lower mold 40 is smaller than the lower surface of the glass sheet 2 and does not come into contact with the peripheral edge of the lower surface of the glass sheet 2. The lower mold 40 is smaller than the ring mold 21 and rises inside the ring mold 21, pressing the center of the lower surface of the glass sheet 2. A second lifting mechanism 47 raises and lowers the lower mold 40 in the press zone Z2.

[0068] Next, the operation of the bending apparatus 1 according to the second embodiment will be described with reference to Figs. 6 to 8. A series of operations shown in Figs. 6 to 8 is performed under the control of the control unit 90. First, the conveyor 25 moves a plurality of carriers 20 together (step S301). As a result, as shown in Fig. 6, one carrier 20 is placed in the press zone Z2. A glass sheet 2 is placed on the carrier 20.

[0069] 7(A), the second lifting mechanism 47 lifts the bottom mold 40 (step S302). The bottom mold 40 lifts inside the ring mold 21, receives the glass sheet 2 from the ring mold 21, and lifts it up from the ring mold 21. Note that the glass sheet 2 may be supported from below by both the ring mold 21 and the bottom mold 40, without being lifted up from the ring mold 21.

[0070] 7(B), the first lifting mechanism 37 lowers the upper mold 30 (step S303), causing the upper mold 30 and the lower mold 40 to sandwich and press the glass sheet 2.

[0071] 7(C), the first lifting mechanism 37 raises the top mold 30 above the movement path of the carrier 20 (step S304). Before or during the ascent of the top mold 30, the gas ejection holes in the bottom surface 31 of the top mold 30 may eject gas downward, and the pressure of the gas ejection may be used to peel the glass sheet 2 from the top mold 30.

[0072] 7(D), the second lifting mechanism 47 lowers the lower mold 40 below the movement path of the carrier 20 (step S305). The lower mold 40 descends inside the frame-shaped ring mold 21 and delivers the glass sheet 2 to the ring mold 21.

[0073] Thereafter, step S301 is performed again, and the press-formed glass sheet 2 is moved together with the carrier 20 from the press zone Z2 to the post-treatment zone Z4. Thereafter, the glass sheet 2 is taken out together with the carrier 20 to the outside of the gravity forming furnace 10.

[0074] The bending apparatus and bending method according to the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0075] This application claims priority based on Patent Application No. 2021-015486 filed with the Japan Patent Office on February 3, 2021, and the entire contents of Patent Application No. 2021-015486 are incorporated herein by reference. [Explanation of symbols]

[0076] 1. Bending device 10 Gravity forming furnace 20 Career 21 Ring type 25 Conveyor 27 Second lifting mechanism 29 Slide mechanism 30 Upper mold 37 First lifting mechanism 40 Lower mold

Claims

1. a gravity forming furnace having a press zone and an evacuation zone formed therein; a plurality of carriers arranged at intervals inside the gravity forming furnace, each including a ring mold for supporting the peripheral edge of the glass sheet from below; a conveyor for moving the plurality of carriers at once; an upper mold that presses the glass sheet from above in the press zone; a first lifting mechanism that lifts and lowers the upper mold in the press zone; a lower mold that supports the glass sheet from below in the press zone; attaching and detaching the carrier to and from the conveyor in the evacuation zone; a second elevator that raises and lowers the carrier removed from the conveyor in the evacuation zone; a slide mechanism for attaching and detaching the carrier to and from the conveyor in the press zone and for sliding the carrier removed from the conveyor between the press zone and the evacuation zone, A bending apparatus, wherein the upper surface of the lower mold supports the entire lower surface of the glass sheet when the upper mold presses the glass sheet from above.

2. The bending apparatus according to claim 1 , wherein the upper surface of the lower mold does not include any gas suction holes.

3. The bending apparatus according to claim 1 or 2, wherein the lower surface of the upper mold presses against the entire upper surface of the glass sheet.

4. The bending apparatus according to any one of claims 1 to 3, wherein the lower surface of the upper mold includes gas injection holes.

5. a suction device that sucks the glass sheet into the upper mold; The bending apparatus according to any one of claims 1 to 4, wherein the aspirator includes a suction cover that forms an annular slit around the lower surface of the upper mold for aspirating gas.

6. The bending apparatus according to claim 5 , wherein the lower surface of the upper mold does not include any gas suction holes.

7. A bending method comprising bending the glass sheet using the bending apparatus according to any one of claims 1 to 6.

8. a gravity forming furnace that forms a press zone therein; a plurality of carriers arranged at intervals inside the gravity forming furnace, each including a ring mold for supporting the peripheral edge of the glass sheet from below; a conveyor for moving the plurality of carriers at once; an upper mold that presses the glass sheet from above in the press zone; a first lifting mechanism that lifts and lowers the upper mold in the press zone; a lower mold that supports the glass sheet from below in the press zone; a second lifting mechanism that lifts and lowers the lower mold in the press zone; Equipped with the lower mold moves up and down inside the ring mold of the carrier; an upper surface of the lower mold supports the center of the lower surface of the glass sheet when the upper mold presses the glass sheet from above; In the bending apparatus, the glass sheet is supported from below by both the ring mold and the lower mold without being lifted from the ring mold.

9. The bending apparatus according to claim 8 , wherein the upper surface of the lower mold does not include any gas suction holes.

10. The bending apparatus according to claim 8 or 9, wherein the lower surface of the upper mold presses against the entire upper surface of the glass sheet.

11. The bending apparatus according to any one of claims 8 to 10, wherein the lower surface of the upper mold includes gas injection holes.

12. The bending apparatus according to any one of claims 8 to 11, wherein the lower surface of the upper mold does not include a gas suction hole.

13. A bending method comprising bending the glass sheet using the bending apparatus according to any one of claims 8 to 12.

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