Top roll, glass plate manufacturing apparatus, and glass plate manufacturing method

Abstract

The present invention provides a top roll, a glass plate manufacturing apparatus, and a manufacturing method that can suppress dust from falling from the first insulating material onto the glass ribbon and reduce the drawbacks of the glass ribbon. [Solution] The top roll 33 supports the glass ribbon GR. The top roll 33 comprises a rotating roll 331 that contacts the upper surface of the glass ribbon GR, a rotating shaft 332 that rotates the rotating roll 331, a first heat insulating material 333 that covers the outer circumferential surface of the rotating shaft 332, and a first cover 334 that covers the outer circumferential surface of the first heat insulating material 333. The first cover 334 contains carbon.

Description

Technical Field

[0001] The present disclosure relates to a top roll, a glass sheet manufacturing apparatus, and a glass sheet manufacturing method.

Background Art

[0002] As a method for manufacturing a glass sheet, the float method is known. In the float method, molten glass is continuously supplied onto the surface of molten metal, and the molten glass is formed into a ribbon shape on the surface of the molten metal. The glass formed into a ribbon shape is also called a glass ribbon. The glass ribbon gradually cools and solidifies while flowing in a predetermined direction on the surface of the molten metal.

[0003] The thickness of the glass ribbon becomes an equilibrium thickness determined by the balance between gravity and surface tension if no external force is applied to the glass ribbon. To form a glass ribbon thinner than the equilibrium thickness, a top roll is used (see, for example, Patent Document 1). The top roll is provided on both sides in the width direction of the glass ribbon and applies tension in the width direction of the glass ribbon.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The top roll includes a rotating roll that contacts the upper surface of the glass ribbon and a rotating shaft that rotates the rotating roll. The rotating roll and the rotating shaft have a refrigerant flow path inside. As the refrigerant, for example, water is used. The refrigerant absorbs heat from the rotating roll and the rotating shaft and discharges the absorbed heat to the outside of the forming furnace, thereby keeping the temperatures of the rotating roll and the rotating shaft below the heat-resistant temperature.

[0006] The top roll is equipped with a first insulating material that covers the outer surface of the rotating shaft. The first insulating material restricts heat transfer between the rotating shaft and the glass ribbon, suppressing overheating of the rotating shaft and inhibiting the cooling and solidification of the glass ribbon. By suppressing the cooling and solidification of the glass ribbon, the rotating roll can easily bite into the glass ribbon, and sufficient tension can be applied to the glass ribbon.

[0007] By the way, if the top roll is equipped with a first insulation material, the first insulation material may deteriorate due to heat and generate dust. If this dust falls onto the glass ribbon, it can cause defects in the glass ribbon.

[0008] One aspect of this disclosure provides a technique for reducing the defects of glass ribbons. [Means for solving the problem]

[0009] A top roll according to one aspect of the present disclosure supports a glass ribbon. The top roll comprises a rotating roll in contact with the upper surface of the glass ribbon, a rotating shaft for rotating the rotating roll, a first insulating material covering the outer circumferential surface of the rotating shaft, and a first cover covering the outer circumferential surface of the first insulating material. The first cover contains carbon. [Effects of the Invention]

[0010] According to one aspect of this disclosure, by providing a first cover containing heat-resistant carbon on the outer surface of the first heat-insulating material, it is possible to suppress dust falling from the first heat-insulating material onto the glass ribbon, thereby reducing the drawbacks of the glass ribbon. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a cross-sectional view showing a glass plate manufacturing apparatus according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view showing an example of a molding apparatus. [Figure 3] Figure 3 is a plan view showing an example of the arrangement of the top rolls. [Figure 4] Figure 4 is a cross-sectional view showing an example of the structure of a top roll. [Figure 5] Figure 5 is a cross-sectional view showing an example of the first fixing device. [Figure 6] Figure 6 is a cross-sectional view showing an example of the second fixing device. [Modes for carrying out the invention]

[0012] Embodiments of this disclosure will be described below with reference to the drawings. Note that identical or corresponding components in each drawing are denoted by the same reference numerals, and their descriptions may be omitted. In each drawing, 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. The X-axis direction is the transport direction of the glass ribbon GR, and the Y-axis direction is the width direction of the glass ribbon GR. In this specification, the "~" indicating a numerical range means that the numbers before and after it are included as the lower and upper limits, respectively. The numerical range includes rounded ranges.

[0013] First, with reference to Figure 1, a glass plate manufacturing apparatus 1 according to one embodiment will be described. The glass plate manufacturing apparatus 1 manufactures glass plates by the float process. The glass plates are, for example, alkali-free glass, aluminosilicate glass, borosilicate glass, or soda-lime glass. Alkali-free glass means glass that does not substantially contain alkali metal oxides such as Na2O and K2O. Here, substantially free of alkali metal oxides means that the total amount of alkali metal oxides contained is 0.1% by mass or less.

[0014] The uses of glass plates are not particularly limited, but one example is as cover glass for displays (e.g., liquid crystal displays or organic EL displays). When the glass plate is used as cover glass, it is chemically strengthened glass. Unlike alkali-free glass, chemically strengthened glass contains alkali metal oxides.

[0015] The thickness of the glass plate is selected according to the use of the glass plate. When the use of the glass plate is a cover glass for a display, the thickness of the glass plate is, for example, 0.1 mm to 5.0 mm. When the use of the glass plate is a glass substrate for a display, the thickness of the glass plate is, for example, 0.1 mm to 0.7 mm. When the use of the glass plate is an automobile windshield, the thickness of the glass plate is, for example, 0.2 mm to 3.0 mm.

[0016] The glass plate manufacturing apparatus 1 includes, for example, a melting apparatus 2, a forming apparatus 3, and an annealing apparatus 4 in this order.

[0017] The melting apparatus 2 includes, for example, a melting furnace 21 that houses molten glass G, and a burner 22 that forms a flame above the molten glass G housed in the melting furnace 21. The glass raw material introduced into the melting furnace 21 gradually melts into the molten glass G by the radiant heat from the flame formed by the burner 22. The molten glass G is continuously conveyed from the melting apparatus 2 to the forming apparatus 3. The heating source is not limited to the burner 22, and may be an electric heater or an electrode, etc. The electrode generates heat in the molten glass G by passing an electric current through the molten glass G.

[0018] The forming apparatus 3 includes a forming furnace 31, and forms the molten glass G into a desired shape inside the forming furnace 31. The forming furnace 31 has, for example, a bath 311. The bath 311 houses molten metal M. As the molten metal M, for example, molten tin is used. In addition to molten tin, molten tin alloys, etc. can also be used, and the molten metal M may have a density higher than that of the molten glass G. The molten glass G is continuously supplied onto the molten metal M, and is formed into a strip-shaped glass ribbon GR using the smooth liquid surface of the molten metal M.

[0019] The forming furnace 31 has a ceiling 312 above the bath 311. The inside of the forming furnace 31 is filled with a reducing gas and maintained at a pressure higher than the atmospheric pressure to prevent oxidation of the molten metal M. The reducing gas is, for example, a mixed gas of nitrogen gas and hydrogen gas, and contains 85 vol% to 98.5 vol% of nitrogen gas and 1.5 vol% to 15 vol% of hydrogen gas. The reducing gas is supplied through the joints between the bricks of the ceiling 312 and the holes in the ceiling 312.

[0020] The forming device 3 includes a heater 32 for heating the glass ribbon GR. The heater 32 is, for example, suspended from the ceiling 312 of the forming furnace 31 and heats the glass ribbon GR passing below. The heater 32 is, for example, an electric heater and is heated by energization. A plurality of heaters 32 are arranged in a matrix in the conveying direction and width direction of the glass ribbon GR. By controlling the outputs of the plurality of heaters 32, the temperature distribution of the glass ribbon GR can be controlled, and the plate thickness distribution of the glass ribbon GR can be controlled.

[0021] The slow cooling device 4 slowly cools the glass ribbon GR formed by the forming device 3. The slow cooling device 4 has, for example, a heat treatment furnace and conveying rolls for conveying the glass article in a desired direction inside the heat treatment furnace. The conveying rolls are, for example, arranged in a plurality at intervals in the horizontal direction. The glass ribbon GR is slowly cooled while being conveyed from the inlet of the heat treatment furnace to the outlet of the heat treatment furnace. By slowly cooling the glass ribbon GR, the residual strain can be reduced.

[0022] The slow cooling device 4 comprises a dross box 41 and a lift-out roll 42. The dross box 41 is an example of a heat treatment furnace. The lift-out roll 42 is positioned inside the dross box 41 and lifts the glass ribbon GR from the molten metal M. The lift-out roll 42 is an example of a conveying roll. Multiple lift-out rolls 42 are arranged at intervals in the conveying direction (X-axis direction) of the glass ribbon GR. The number of lift-out rolls 42 is not particularly limited. The lift-out roll 42 is rotationally driven by a drive device such as a motor (not shown), and the driving force conveys the glass ribbon GR diagonally upward. The axial direction of the lift-out roll 42 is the same as the width direction (Y-axis direction) of the glass ribbon GR.

[0023] The slow cooling device 4 may be equipped with a heater (not shown) on the ceiling of the dross box 41 to adjust the temperature of the glass ribbon GR. The heater may be provided not only above the glass ribbon GR but also below it. Inside the dross box 41, the temperature of the glass ribbon GR is preferably (Tg-50)°C to (Tg+30)°C, with respect to the glass transition point Tg of the glass ribbon GR.

[0024] The annealing device 4 comprises an annealing furnace 45 and layer rolls 46. The annealing furnace 45 is located downstream of the dross box 41. The annealing furnace 45 is an example of a heat treatment furnace. The layer rolls 46 are located inside the annealing furnace 45 and transport the glass ribbon GR in the longitudinal direction (X-axis direction) of the glass ribbon GR. The layer rolls 46 are an example of a transport roll. Multiple layer rolls 46 are provided at intervals in the transport direction of the glass ribbon GR. The number of layer rolls 46 is not particularly limited. The layer rolls 46 are rotationally driven by a drive device such as a motor (not shown), and the driving force transports the glass ribbon GR in the horizontal direction (X-axis direction). The axial direction of the layer rolls 46 is the same as the width direction (Y-axis direction) of the glass ribbon GR.

[0025] The annealing device 4 slowly cools the glass ribbon GR to a temperature below the strain point of the glass while conveying it with a layer roll 46. The annealing device 4 may be equipped with a heater (not shown) inside the annealing furnace 45 to adjust the temperature of the glass ribbon GR.

[0026] Next, with reference to Figure 2, the molding apparatus 3 will be described in detail. The molding apparatus 3 includes a molding furnace 31 that houses the molten glass G inside. The molding furnace 31 includes, for example, a bathtub 311, a ceiling 312, and side walls 313. The side walls 313 are provided above the bathtub 311. The side walls 313 have a brick layer 314 and a metal layer 315 provided outside the brick layer 314. The side walls 313 are provided on both sides in the width direction of the glass ribbon GR (positive Y-axis side and negative Y-axis side).

[0027] The molding apparatus 3 includes a top roll 33. The top roll 33 is inserted into the molding furnace 31 through a gap formed between the bath tub 311 and the side wall 313. The top roll 33 supports the glass ribbon GR. The top roll 33 is in contact with the upper surface of the glass ribbon GR, and the molten metal M is in contact with the lower surface of the glass ribbon GR. The upper surface of the glass ribbon GR is sometimes called the top surface. The lower surface of the glass ribbon GR is sometimes called the bottom surface.

[0028] As shown in Figure 3, a pair of top rolls 33 are provided on both sides of the glass ribbon GR in the width direction. The pair of top rolls 33 suppress the shrinkage of the glass ribbon GR in the width direction. The thickness of the glass ribbon GR can be made thinner than the equilibrium thickness. Multiple pairs of top rolls 33 are provided at intervals in the flow direction (X-axis direction) of the glass ribbon GR. The glass ribbon GR flows on the liquid surface of the molten metal M and is gradually cooled and solidified.

[0029] Next, the details of the top roll 33 will be described with reference to Figures 4 to 8. As shown in Figure 4, the top roll 33 comprises a rotating roll 331 that contacts the upper surface of the glass ribbon GR, and a rotating shaft 332 that rotates the rotating roll 331. The outer diameter of the rotating roll 331 is larger than the outer diameter of the rotating shaft 332, and the outer circumference of the rotating roll 331 contacts the upper surface of the glass ribbon GR. The outer circumference of the rotating shaft 332 does not contact the upper surface of the glass ribbon GR. The rotating roll 331 is provided at one end of the rotating shaft 332, and a drive source (not shown) is provided at the other end of the rotating shaft 332. The drive source includes a rotary motor. The drive source is provided outside the molding furnace 31.

[0030] The rotating roll 331 and the rotating shaft 332 have internal coolant passages, although these are not shown. For example, water is used as the coolant. The coolant absorbs heat from the rotating roll 331 and the rotating shaft 332 and discharges the absorbed heat to the outside of the molding furnace 31, thereby maintaining the temperature of the rotating roll 331 and the rotating shaft 332 below the heat resistance temperature. The rotating shaft 332 is, for example, constructed as a double pipe and has a forward passage for the coolant and a return passage for the coolant.

[0031] The top roll 33 is equipped with a first heat insulating material 333 that covers the outer surface of the rotating shaft 332. The outer diameter of the first heat insulating material 333 is smaller than the outer diameter of the rotating roll 331, and the outer surface of the first heat insulating material 333 does not come into contact with the upper surface of the glass ribbon GR. The first heat insulating material 333 restricts heat transfer between the rotating shaft 332 and the glass ribbon GR, suppressing overheating of the rotating shaft 332 and suppressing the cooling and solidification of the glass ribbon GR. By suppressing the cooling and solidification of the glass ribbon GR, the rotating roll 331 can easily bite into the glass ribbon GR, and sufficient tension can be applied to the glass ribbon GR. The first heat insulating material 333 is an insulating material.

[0032] The first heat-insulating material 333 preferably has a porous body in order to suppress heat transfer. The porous body is, for example, an aggregate of inorganic fibers and inorganic particles. The inorganic fibers and inorganic particles are composed of, for example, ceramic, glass, or carbon. The ceramic includes, for example, silicon oxide, aluminum oxide, or a compound of silicon oxide and aluminum oxide. The first heat-insulating material 333 may further include an inorganic binder. The first heat-insulating material 333 may also include a rope for bundling the above aggregates.

[0033] The porous material constituting the first heat-insulating material 333 preferably contains carbon. This is because even if dust from the porous material adheres to the glass ribbon GR, the carbon dust will burn off in the annealing furnace 45. Unlike the molding furnace 31, the annealing furnace 45 is filled with air. The carbon dust reacts with oxygen in the air and gasifies. Therefore, even if carbon dust adheres to the glass ribbon GR, it hardly remains as a defect.

[0034] The first insulation material 333 is formed in a cylindrical shape. A through hole is formed in the center of the first insulation material 333. The rotating shaft 332 is inserted through this through hole. Preferably, the first insulation material 333 covers the outer surface of the rotating shaft 332 over its entire circumference.

[0035] The top roll 33 includes a first cover 334 that covers the outer surface of the first insulation material 333. The first cover 334 is preferably made of a material that suppresses dust generation compared to the first insulation material 333, and preferably has high hardness or high density. The outer diameter of the first cover 334 is smaller than the outer diameter of the rotating roll 331, and the outer surface of the first cover 334 does not come into contact with the upper surface of the glass ribbon GR.

[0036] The first cover 334 contains carbon. Carbon has a low coefficient of thermal expansion and high thermal conductivity, and is excellent in thermal shock resistance. By providing the first cover 334, which has excellent thermal shock resistance, on the outer surface of the first insulation material 333, the falling of dust from the first insulation material 333 onto the glass ribbon GR can be suppressed, and the drawbacks of the glass ribbon GR can be reduced. Furthermore, even if carbon dust adheres to the glass ribbon GR, it will not remain as a defect if it is burned off in the annealing furnace 45.

[0037] The first cover 334 preferably has a cylindrical portion 334a that covers the outer circumferential surface of the first insulation material 333 and a lid portion 334b ​​that covers the end face of the first insulation material 333 opposite to the rotating roll 331. By covering not only the outer circumferential surface of the first insulation material 333 but also the end face of the first insulation material 333 with the first cover 334, dust generation from the end face of the first insulation material 333 can be suppressed.

[0038] The first cover 334 does not need to cover the end face of the first insulation material 333 that faces the rotating roll 331. By pressing the end face of the first insulation material 333 against the rotating roll 331, dust generation from the end face of the first insulation material 333 can be suppressed. Also, by pressing the end face of the first insulation material 333 against the rotating roll 331, the temperature rise of the rotating roll 331 can be suppressed, as will be described later.

[0039] Since the first cover 334 has a higher thermal conductivity than the first insulation material 333, it is not necessary to cover the end face of the first insulation material 333 that faces the rotating roll 331 in order to suppress the temperature rise of the rotating roll 331. The thermal conductivity of the first cover 334 is, for example, 5 W / (m·°C) to 150 W / (m·°C) at room temperature, preferably 70 W / (m·°C) to 130 W / (m·°C).

[0040] The thickness t of the first cover 334 is preferably 3.0 mm to 10.0 mm. If the thickness t of the first cover 334 is 3.0 mm or more, the rigidity of the first cover 334 is high and the handling of the first cover 334 is good. If the thickness t of the first cover 334 is 10.0 mm or less, the weight of the first cover 334 can be reduced. The thickness t of the first cover 334 is more preferably 4.0 mm to 8.0 mm, and even more preferably 5.0 mm to 7.0 mm.

[0041] The bulk density of the first cover 334 is preferably 1.4 g / cm³. 3 ~2.1 g / cm³ 3 The bulk density of the first cover 334 is 1.4 g / cm³. 3 If the above conditions are met, the rigidity of the first cover 334 is high and the handling of the first cover 334 is good. The bulk density of the first cover 334 is 2.1 g / cm³. 3 The first cover 334 can be made lighter if the following conditions are met.

[0042] The tensile strength of the first cover 334 is preferably 20 MPa to 250 MPa. If the tensile strength of the first cover 334 is 20 MPa or more, the strength of the first cover 334 is high and the handling properties of the first cover 334 are good. If the tensile strength of the first cover 334 is 250 MPa or less, the weight of the first cover 334 can be reduced. The tensile strength of the first cover 334 is more preferably 20 MPa to 100 MPa, and even more preferably 30 MPa to 50 MPa.

[0043] The Shore hardness of the first cover 334 is preferably 50HSD to 90HSD. If the Shore hardness of the first cover 334 is 50HSD or higher, the strength of the first cover 334 is high and the handling of the first cover 334 is good. If the Shore hardness of the first cover 334 is 90HSD or lower, the weight of the first cover 334 can be reduced. The Shore hardness of the first cover 334 is more preferably 50HSD to 80HSD, and even more preferably 50HSD to 70HSD.

[0044] The first cover 334 preferably includes CIP (Cold Isostatic Press) material or C / C composite (Carbon Fiber Reinforced Carbon Composite) material. The CIP material and C / C composite material have a bulk density within the above numerical range, a tensile strength within the above numerical range, and a Shore hardness within the above numerical range.

[0045] As shown in Figure 5, it is preferable that the top roll 33 is equipped with a first fixing device 335 that secures the first cover 334 to the rotating shaft 332. The first fixing device 335 has a first fixing rod 335a. The first fixing rod 335a protrudes radially outward from the rotating shaft 332 and is inserted through a through hole in the first insulation material 333, connecting the rotating shaft 332 and the first cover 334. Unlike when using adhesives, drying of the adhesive is unnecessary, so the working time is short.

[0046] The first fixed rod 335a has a first threaded shaft 335a1 at one axial end and a second threaded shaft 335a2 at the other axial end. The first threaded shaft 335a1 is fastened to a first nut 335b provided on the outer circumferential surface of the rotating shaft 332. The second threaded shaft 335a2 is fastened to a second nut 335c that presses against the outer circumferential surface of the first cover 334.

[0047] The first fixing device 335 preferably contains carbon. For example, the first fixing rod 335a and the second nut 335c are preferably made of carbon, similar to the first cover 334. This is because even if carbon dust adheres to the glass ribbon GR, the carbon dust will burn off in the annealing furnace 45. On the other hand, the first nut 335b is preferably made of metal, similar to the rotating shaft 332. The first nut 335b and the rotating shaft 332 can be integrated by welding or other means.

[0048] The first cover 334 may be divided into two parts, a first half-body 334c and a second half-body 334d, in the circumferential direction of the rotation axis 332. In this case, the cylindrical portion 334a and the lid portion 334b ​​constituting the first cover 334 are each divided into two parts. The first half-body 334c and the second half-body 334d have a fitting portion that fits together with each other. The fitting portion is composed of a recess and a protrusion.

[0049] One first fixing device 335 fixes the first half-body 334c to the rotation axis 332, and another first fixing device 335 fixes the second half-body 334d to the rotation axis 332. Preferably, the first fixing rod 335a of each first fixing device 335 is provided perpendicular to the dividing surface of the first half-body 334c and the second half-body 334d. Preferably, the pair of first fixing rods 335a are arranged symmetrically around the rotation axis 332.

[0050] As shown in Figure 4, the top roll 33 preferably includes a fixed shaft 337. The fixed shaft 337 has a through hole through which the rotating shaft 332 is inserted. The fixed shaft 337 rotatably supports the rotating shaft 332 and reduces vibration of the rotating shaft 332. A sleeve (not shown) to reduce frictional resistance may be provided between the fixed shaft 337 and the rotating shaft 332. The rotating shaft 332 protrudes from the fixed shaft 337, and the first insulation material 333 is provided on the protruding portion. The first insulation material 333 rotates together with the rotating shaft 332. The outer diameter of the fixed shaft 337 is smaller than the outer diameter of the rotating roll 331, and the outer circumference of the fixed shaft 337 does not contact the upper surface of the glass ribbon GR.

[0051] The top roll 33 preferably includes a second heat-insulating material 338 that covers the outer surface of the fixed shaft 337. The outer diameter of the second heat-insulating material 338 is smaller than the outer diameter of the rotating roll 331, and the outer surface of the second heat-insulating material 338 does not come into contact with the upper surface of the glass ribbon GR. The second heat-insulating material 338 restricts heat transfer between the fixed shaft 337 and the glass ribbon GR, suppressing overheating of the fixed shaft 337 and suppressing the cooling and solidification of the glass ribbon GR. The second heat-insulating material 338 is an insulating material. Unlike the first heat-insulating material 333, the second heat-insulating material 338 does not rotate with the rotating shaft 332.

[0052] The second heat-insulating material 338, like the first heat-insulating material 333, preferably has a porous body in order to suppress heat transfer. The porous body is an aggregate of at least one inorganic fiber and inorganic particles. The porous body constituting the second heat-insulating material 338 preferably contains carbon. This is because even if dust from the porous body adheres to the glass ribbon GR, the carbon dust will be burned off in the annealing furnace 45.

[0053] The second insulation material 338 is formed in a cylindrical shape. A through hole is formed in the center of the second insulation material 338. The fixing shaft 337 is inserted through this through hole. Preferably, the second insulation material 338 covers the entire outer surface of the fixing shaft 337 in the circumferential direction.

[0054] The top roll 33 preferably includes a second cover 339 that covers the outer surface of the second insulation material 338. The second cover 339 preferably has a material that suppresses dust generation compared to the second insulation material 338, and preferably has high hardness or high density. The outer diameter of the second cover 339 is smaller than the outer diameter of the rotating roll 331, and the outer surface of the second cover 339 does not come into contact with the upper surface of the glass ribbon GR.

[0055] The second cover 339 contains carbon. Carbon has a low coefficient of thermal expansion and high thermal conductivity, and is excellent in thermal shock resistance. By providing the second cover 339, which has excellent thermal shock resistance, on the outer surface of the second insulation material 338, the falling of dust from the second insulation material 338 onto the glass ribbon GR can be suppressed, and the drawbacks of the glass ribbon GR can be reduced. Furthermore, even if carbon dust adheres to the glass ribbon GR, it will not remain as a defect if it is burned off in the annealing furnace 45.

[0056] Preferably, the second cover 339 has a cylindrical portion 339a that covers the outer circumferential surface of the second insulation material 338 and a lid portion 339b that covers the end face of the second insulation material 338 facing the first insulation material 333. By covering not only the outer circumferential surface of the second insulation material 338 but also the end face of the second insulation material 338 with the second cover 339, dust generation from the end face of the second insulation material 338 can be suppressed.

[0057] The second cover 339 may have the same thermal conductivity, thickness, bulk density, tensile strength, and Shore hardness as the first cover 334. The second cover 339 preferably contains a CIP material or a C / C composite material.

[0058] As shown in Figure 6, it is preferable that the top roll 33 is equipped with a second fixing device 340 for fixing the second cover 339 to the fixed shaft 337. The second fixing device 340 has a second fixing rod 340a. The second fixing rod 340a protrudes radially outward from the fixed shaft 337 and is inserted through a through hole in the second insulation material 338, connecting the fixed shaft 337 and the second cover 339. Unlike when adhesives are used, drying of the adhesive is not required, so the working time is short.

[0059] The second fixed rod 340a has a first threaded shaft 340a1 at one axial end and a second threaded shaft 340a2 at the other axial end. The first threaded shaft 340a1 is fastened to a first nut 340b provided on the outer circumferential surface of the fixed shaft 337. The second threaded shaft 340a2 is fastened to a second nut 340c that presses against the outer circumferential surface of the second cover 339.

[0060] The second fixing device 340 preferably contains carbon. For example, the second fixing rod 340a and the second nut 340c are preferably made of carbon, similar to the second cover 339. This is because even if carbon dust adheres to the glass ribbon GR, the carbon dust will burn off in the annealing furnace 45. On the other hand, the first nut 340b is preferably made of metal, similar to the fixing shaft 337. The first nut 340b and the fixing shaft 337 can be integrated by welding or other means.

[0061] The second cover 339 may be divided into two parts, a first half-body 339c and a second half-body 339d, in the circumferential direction of the fixed shaft 337. In this case, the cylindrical portion 334a and the lid portion 334b ​​constituting the second cover 339 are each divided into two parts. The first half-body 339c and the second half-body 339d have a fitting portion that fits together with each other. The fitting portion consists of a recess and a protrusion.

[0062] One second fixing device 340 fixes the first half-body 339c to the fixing shaft 337, and another second fixing device 340 fixes the second half-body 339d to the fixing shaft 337. Preferably, the second fixing rod 340a of each second fixing device 340 is provided perpendicular to the dividing surface of the first half-body 339c and the second half-body 339d. Preferably, the pair of second fixing rods 340a are arranged symmetrically around the fixing shaft 337.

[0063] The following additional information is disclosed regarding the above embodiments, etc.

[0064] [Note 1] A top roll supporting a glass ribbon, A rotating roll in contact with the upper surface of the glass ribbon, A rotating shaft that rotates the aforementioned rotating roll, A first heat-insulating material covering the outer surface of the rotating shaft, A first cover that covers the outer surface of the first insulation material, Equipped with, The first cover is a top roll containing carbon. [Note 2] The first cover has a bulk density of 1.4 g / cm³. 3 ~2.1 g / cm³ 3 This is the top roll described in Appendix 1. [Note 3] The first cover is a top roll as described in Appendix 2, which includes CIP (Cold Isostatic Press) material or C / C composite (Carbon Fiber Reinforced Carbon Composite) material. [Note 4] The first heat-insulating material has a porous body, and the porous body contains carbon, as described in any one of the appendices 1 to 3. [Note 5] A top roll according to any one of the appendices 1 to 4, comprising a first fixing device for fixing the first cover to the rotating shaft, the first fixing device having a first fixing rod, the first fixing rod protruding radially outward from the rotating shaft and inserted through a through hole in the first insulation material, connecting the rotating shaft and the first cover. [Note 6] The first fixing device is a top roll containing carbon, as described in Appendix 5. [Note 7] The first cover is divided into two parts, a first half and a second half, in the circumferential direction of the rotation axis. One of the first fixing devices secures the first half-body to the rotation axis, and another of the first fixing devices secures the second half-body to the rotation axis. The top roll according to Appendix 5 or 6, wherein the first fixing rod of each of the first fixing devices is provided perpendicular to the dividing surfaces of the first half and the second half. [Note 8] The top roll according to any one of the appendices 1 to 7, wherein the first cover has a cylindrical portion that covers the outer surface of the first insulation material and a lid portion that covers the end face of the first insulation material opposite to the rotating roll. [Note 9] A fixed shaft having a through hole through which the aforementioned rotating shaft is inserted, A second heat-insulating material covering the outer surface of the fixed shaft, A second cover that covers the outer surface of the second insulation material, Equipped with, The second cover is a top roll containing carbon, as described in any one of the appendices 1 to 8. [Note 10] The top roll described in any one of the appendices 1 to 9, A bathtub containing molten metal in contact with the lower surface of the glass ribbon, A glass plate manufacturing apparatus equipped with the following features. [Note 11] A method for manufacturing a glass plate, comprising forming the glass ribbon on the surface of molten metal using a top roll described in any one of the appendices 1 to 9.

[0065] The top roll, glass plate manufacturing apparatus, and glass plate manufacturing method relating to this disclosure have been described above, but this disclosure is not limited to the embodiments described above. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims, and these also naturally fall within the technical scope of this disclosure. [Explanation of symbols]

[0066] 1. Glass plate manufacturing apparatus 3 Molding equipment 33 Top Roll 331 Rotating Roll 332 Rotation axis 333 1st insulation material 334 First Cover 335 1st fixture 337 Fixed axis 338 Second insulation material 339 Second Cover 340 Second fixture GR Glass Ribbon

Claims

1. A top roll supporting a glass ribbon, A rotating roll in contact with the upper surface of the glass ribbon, A rotating shaft that rotates the aforementioned rotating roll, A first heat-insulating material covering the outer surface of the rotating shaft, A first cover that covers the outer surface of the first insulating material, Equipped with, The first cover is a top roll containing carbon.

2. The first cover has a bulk density of 1.4 g / cm³. ３ ~2.1 g / cm ３ The top roll according to claim 1.

3. The top roll according to claim 2, wherein the first cover comprises a CIP (Cold Isostatic Press) material or a C / C composite (Carbon Fiber Reinforced Carbon Composite) material.

4. The top roll according to any one of claims 1 to 3, wherein the first heat-insulating material has a porous body, and the porous body contains carbon.

5. The top roll according to any one of claims 1 to 3, further comprising a first fixing device for fixing the first cover to the rotating shaft, the first fixing device having a first fixing rod, the first fixing rod protruding radially outward from the rotating shaft and inserted through a through hole in the first heat-insulating material, and connecting the rotating shaft and the first cover.

6. The top roll according to claim 5, wherein the first fastener includes carbon.

7. The first cover is divided into two parts, a first half and a second half, in the circumferential direction of the rotation axis. One of the first fixing devices fixes the first half-body to the rotation axis, and another of the first fixing devices fixes the second half-body to the rotation axis. The top roll according to claim 5, wherein the first fixing rod of each of the first fixing devices is provided perpendicular to the dividing surfaces of the first half and the second half.

8. The top roll according to any one of claims 1 to 3, wherein the first cover has a cylindrical portion that covers the outer surface of the first insulating material and a lid portion that covers the end face of the first insulating material opposite to the rotating roll.

9. A fixed shaft having a through hole through which the aforementioned rotating shaft is inserted, A second heat-insulating material covers the outer surface of the aforementioned fixed shaft, A second cover that covers the outer surface of the second insulation material, Equipped with, The top roll according to any one of claims 1 to 3, wherein the second cover comprises carbon.

10. A top roll according to any one of claims 1 to 3, A bathtub containing molten metal in contact with the lower surface of the glass ribbon, A glass plate manufacturing apparatus equipped with the following features.

11. A method for manufacturing a glass plate, comprising forming the glass ribbon on the liquid surface of molten metal using the top roll described in any one of claims 1 to 3.

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