TWI714885B - Method for manufacturing glass substrate and glass substrate manufacturing apparatus - Google Patents

Abstract

The subject of the present invention is to suppress the breakage of the glass plate when the glass plate continuously stretched after being formed is clamped by a plurality of conveying rollers and cooled while being conveyed. The present invention relates to a manufacturing method of a glass plate and a manufacturing device of the glass plate. The area on both sides of the width direction of the glass sheet after the molten glass is formed by the overflow down-draw method is clamped by a plurality of conveying roller pairs arranged in the conveying direction of the glass sheet, and the glass sheet is conveyed downward. cool down. During this cooling, in at least one of the plurality of conveying roller pairs having a first roller and a second roller, the first roller is used to sandwich the glass plate with respect to the second roller to fix the force The pressing method controls the relative position of the first roller with respect to the second roller, and further, according to the degree of abrasion of the first roller and the second roller, intermittently moves the second roller in the direction of the first roller Forced displacement.

Description

Glass plate manufacturing method and glass plate manufacturing device

The present invention relates to a manufacturing method of a glass plate and a manufacturing device of the glass plate.

In the manufacturing method of the glass plate using the down-draw method, in the forming step, the molten glass is overflow-shaped from the formed body into a continuously extending glass sheet (glass plate). Then, in the subsequent cooling step, the glass plate is clamped by a pair of conveying rollers and pulled in the downward direction, and stretched to the desired thickness without internal strain, and the glass plate is not warped The way of bending is to cool the glass plate. Then, the glass plate is cut to a specific size, and after washing and inspection, the glass plate that meets the prescribed quality is regarded as a qualified product and formed into a glass substrate for a display device such as a liquid crystal display device.

For example, there is known a method for manufacturing a glass plate, which includes: a forming device that uses an overflow down-draw method to flow the molten glass produced by melting the glass material down the side wall of the formed body to form a glass plate; and a slow cooling device, which Equipped with a slow cooling furnace that clamps the areas on both sides of the width direction of the glass plate obtained by forming by a plurality of conveying roller pairs arranged in the conveying direction of the glass plate, and conveys the glass plate downwards and then cools it; When cooling in the slow cooling furnace, it is possible to suppress the wave shape deformation in the adjacent area adjacent to the part of the glass plate clamped by a plurality of conveying rollers (Patent Document 1). [Advanced Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-136515

[The problem to be solved by the invention]

In the above-mentioned manufacturing method, the both ends of the formed glass plate in the width direction are cooled faster than the center part in the width direction of the glass plate, and the glass plate is not plastically deformed to make the tension Acting on the glass plate in the conveying direction can suppress the wave shape deformation in the adjacent area adjacent to the part of the glass plate clamped by the conveying roller pair. The pair of conveying rollers clamps the surfaces on both sides of the glass plate, while pressing the glass plate with a fixed force, while self-rotating, conveys the glass plate. Thereby, the conveying speed of the glass plate can be controlled so that the tension acts on the glass plate in the conveying direction. In this way, in order to make each of the plural conveying roller pairs press the glass plate with a fixed force, one of the conveying roller pairs (hereinafter referred to as conveying roller A) is opposed to the other fixed conveying roller (hereafter, It is called conveying roller B) by pressing the glass plate with a fixed force, and then pressing the conveying roller B, the relative position of the conveying roller A with respect to the conveying roller B is controlled.

In addition, in recent years, the temperature in the slow cooling furnace has risen, and the rotation speed of the conveying roller has increased due to the thinning of the glass plate, and the conveying roller is more likely to wear out than before. In order to keep the force of the conveying roller A against the glass plate constant, the position of the conveying roller A is controlled by maintaining the relative position of the conveying roller A with respect to the conveying roller B. Therefore, the conveying rollers are constantly worn out The position of A is shifted away from the position of the conveying roller A in the initial state without being worn. The row of the conveying roller pair in which such a conveying roller pair is arranged is arranged along a straight line extending straight downward from the lower end of the molded body, for example. If a plurality of conveying roller pairs arranged on a straight line are worn to the same degree, the conveying roller A, which is positionally controlled with respect to the conveying roller B, is shifted from the initial position of the unworn, conveying path of the glass plate Also maintained as a straight line. However, when the degree of wear of a plurality of conveying roller pairs is uneven, the following situation occurs: due to the difference in the degree of abrasion of the conveying rollers A and B and the degree of abrasion of the adjacent conveying rollers A and B in the conveying direction, The conveying path of the glass plate being clamped and conveyed is curved. The curvature of the conveying path may become the starting point of the break in the conveyance of the glass plate, and may also affect the forming quality of the glass plate. Furthermore, if the conveying rollers A and B are constantly worn, the surfaces of the conveying rollers A and B will be in the shape of tiny concavities and convexities, and the surface of the glass plate contacting the tiny concavities and convexities will easily produce scratches that become the starting point of the glass plate. In particular, the frequency of breakage of the glass plate increases due to the bending of the conveying path of the glass plate and the scratches.

Therefore, the object of the present invention is to provide a glass plate manufacturing method capable of suppressing the influence of the breakage of the glass plate and the deterioration of the quality of the glass plate when the glass plate continuously stretched after being formed is clamped and transported by a plurality of transport rollers And glass plate manufacturing equipment. [Technical means to solve the problem]

One aspect of the present invention is a method of manufacturing a glass plate. The manufacturing method of the glass substrate has: The forming step, which uses the overflow down-draw method to shape the molten glass to form a glass sheet; and The conveying step involves clamping the regions on both sides of the width direction of the glass plate by a plurality of conveying roller pairs arranged in the conveying direction of the glass plate, and conveying the glass plate downward. In at least one conveying roller pair having a first roller and a second roller among the plurality of conveying roller pairs, the first roller is pressed against the second roller with a fixed force while sandwiching the glass plate. The relative position of the first roller with respect to the second roller, and further, the second roller is intermittently forcibly displaced in the direction of the first roller according to the degree of wear of the first roller and the second roller.

Preferably, the second roller is close to the midpoint of a line segment formed by connecting the center of the rotation axis of the first roller and the center of the rotation axis of the second roller after displacing the second roller so that there is no The center of rotation of the first roller and the center of the rotation axis of the second roller during the abrasion are displaced in the manner of the midpoint of a bisecting line segment formed by connecting the center of the rotation axis of the second roller.

Preferably, when the first roller and the second roller are the conveying roller pair A, the plural conveying roller pairs include a third roller and a fourth roller adjacent to the conveying roller pair A in the conveying direction. The conveying roller pair B of the roller controls the relative position of the third roller with respect to the fourth roller in such a manner that the third roller sandwiches the glass plate with the fourth roller and presses with a fixed force, and further, according to The degree of wear of the third roller and the fourth roller intermittently compulsorily displaces the fourth roller in the direction of the third roller to form the transport roller pair B, For the second roller, the midpoint of the line segment formed by connecting the center of the rotation axis of the first roller and the center of the rotation axis of the second roller after the displacement is close to the position in the extending direction of the line segment will make The center of the rotation axis of the third roller and the center of the rotation axis of the fourth roller are connected in such a way that the midpoint of the halved line segment is displaced in the position in the extending direction. Preferably, the third roller and the fourth roller are located on the upstream side in the conveying direction with respect to the first roller and the second roller. Preferably, the degree of wear of the first roller and the second roller is such that the rotation center axis of the first roller and the rotation center axis of the second roller when the second roller is forcibly displaced The position of the midpoint of the completed line segment is used as the reference position, which is calculated based on the offset of the current position of the midpoint relative to the reference position. Preferably, the degree of abrasion of the first roller and the second roller is based on the cumulative time of conveyance of the glass plate using the first roller and the first roller from when the second roller is forcibly displaced And find out.

Another aspect of the present invention is a glass plate manufacturing device. The manufacturing device has: A forming device, which uses an overflow down-draw method to shape the molten glass to shape the glass sheet; A cooling device, which clamps the areas on both sides of the width direction of the glass plate by a plurality of conveying roller pairs arranged in the conveying direction of the glass plate, and conveys the glass plate downward to cool; and A control device that controls the position of the above-mentioned conveying roller pair. The control device is configured as follows: in at least one conveying roller pair having a first roller and a second roller among the plurality of conveying roller pairs, the glass plate is sandwiched by the first roller relative to the second roller. The method of pressing with a fixed force controls the relative position of the first roller with respect to the second roller. Furthermore, the control device intermittently causes the second roller to intermittently according to the degree of wear of the first roller and the second roller. It is configured to forcibly shift in the direction of the above-mentioned first roller.

Preferably, the control device controls the second roller in a manner that connects the center of the rotation axis of the first roller and the center of the rotation axis of the second roller after the second roller is displaced The midpoint of the halves is close to the midpoint of the line segment formed by connecting the rotation center of the first roller and the rotation axis center of the second roller when there is no wear. [Effects of Invention]

According to the glass plate manufacturing method and the glass plate manufacturing device, it is possible to suppress the influence of the breakage of the glass plate and the deterioration of the quality of the glass plate when the continuously stretched glass plate is clamped and conveyed by a plurality of conveying rollers.

Hereinafter, the manufacturing method of the glass plate and the manufacturing apparatus of the glass plate of one Embodiment are demonstrated in detail. In the method of manufacturing a glass plate of an embodiment, for example, a glass substrate for a TFT (thin film transistor) display is manufactured. The glass plate is manufactured using the overflow down-draw method. Hereinafter, a method of manufacturing a glass plate of an embodiment will be described with reference to the drawings.

(1) Outline of manufacturing method of glass plate First, referring to FIGS. 1 and 2, a plurality of steps included in a method of manufacturing a glass plate and a glass plate manufacturing device 100 used in the plurality of steps will be described. The manufacturing method of a glass plate, as shown in FIG. 1, mainly includes melting step S1, clarification step S2, forming step S3, cooling step S4, and cutting step S5.

The melting step S1 is a step of melting the raw materials of the glass. After the raw materials of the glass are blended so as to have a desired composition, as shown in FIG. 2, they are put into the melting device 11 arranged upstream. The glass raw material includes, for example, SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , CaO, SrO, BaO, and the like. Specifically, a glass raw material having a glass strain point of 660°C or higher is used. The raw material of the glass is melted in the melting device 11 to become molten glass FG. The melting temperature can be adjusted according to the type of glass. In this embodiment, the glass raw material is melted at 1500°C to 1650°C. The molten glass FG is sent to the clarification device 12 through the upstream pipe 23.

The clarification step S2 is a step for removing bubbles in the molten glass FG. The molten glass FG from which bubbles have been removed in the clarification device 12 passes through the downstream pipe 24 and is sent to the forming device 40.

The forming step S3 is a step of forming the molten glass FG into a glass sheet SG which is a sheet-like glass. Specifically, after the molten glass FG is continuously supplied to the molded body 41 included in the molding device 40, it overflows from the groove of the molded body 41. The overflowed molten glass FG flows down along the surface of the formed body 41. The molten glass FG then merges with the lower end 41a of the molded body 41 and is molded into a glass sheet SG. The glass sheet SG has a side part (edge material, end part) located at the end in the width direction, and a central area in the width direction clamped by the side part. The thickness of the side part of the glass sheet SG is formed thicker than the thickness of the central area. The central area of the glass sheet SG is the area that becomes the glass plate of the final product including a fixed plate thickness. When it is desired to shape the plate thickness of the central area of the glass sheet SG to a thin plate of 0.4 mm or less, the plate thickness of the side portion of the glass sheet SG is molded to be thinner than before.

The cooling step S4 is a step of cooling (slow cooling) the glass sheet SG. The glass sheet SG is cooled to a temperature close to room temperature through the cooling step S4. In addition, according to the cooling state in the cooling step S4, the thickness of the glass plate (plate thickness), the amount of warpage of the glass plate, and the amount of strain of the glass plate are determined.

The cutting step S5 is a step of cutting the glass sheet SG that has reached a temperature close to room temperature into a specific size.

In addition, the glass sheet SG cut into a specific size is then subjected to steps such as end surface processing. Hereinafter, the glass sheet SG is referred to as a glass plate.

Hereinafter, the configuration of the forming apparatus 40 included in the manufacturing apparatus 100 of the glass plate will be described with reference to FIGS. 3 to 5. In addition, in this embodiment, the width direction of the glass sheet SG means the direction which cross|intersects the direction (flow direction) in which the glass sheet SG flows down, ie, a horizontal direction.

(2) The composition of the forming device First, FIGS. 3 and 4 show a schematic configuration of the forming apparatus 40. 3 is a cross-sectional view of the forming device 40. FIG. 4 is a side view of the forming device 40.

The forming device 40 has a passage through which the glass sheet SG passes and a space surrounding the passage. The space surrounding the passage is composed of an overflow chamber 20, a forming chamber 30, and a cooling chamber 80.

The overflow chamber 20 is a space in which the molten glass FG sent from the clarification device 12 is formed into a glass sheet SG. The glass sheet SG is a continuously extending glass plate.

The forming chamber 30 is disposed under the overflow chamber 20, and is a space for adjusting the thickness and warpage of the glass sheet SG. In the forming chamber 30, a part of the cooling step is performed. The molten glass FG flows down along the surface of the molded body 41, merges at the lower end 41a of the molded body 41, and is molded into a glass sheet SG. The temperature of the glass sheet SG is gradually lowered at a position downstream of the lower end 41a of the molded body 41. The forming chamber 30 is partitioned by a partition member 50 with respect to the overflow chamber 20.

The cooling chamber 80 is disposed below the forming chamber 30 and is a space for adjusting the amount of strain of the glass sheet SG. Specifically, in the cooling chamber 80, the glass sheet SG in the forming chamber 30 passes through the slow cooling point and the glass strain point, and is cooled to a temperature near room temperature. Furthermore, the cooling chamber 80 is partitioned by the heat insulating member 80a with respect to the molding chamber 30, and the inside of the cooling chamber 80 is partitioned into a plurality of spaces by the heat insulating member 80b.

In addition, the molding device 40 mainly includes a molded body 41, a spacer 50, a cooling roll 51, a temperature adjustment unit 60, pull-down rolls 81a to 81g, heaters 82a to 82g, and a cutting device 90. Furthermore, the molding device 40 includes a control device 500 (see FIG. 5). The control device 500 controls the driving parts of the respective components included in the molding device 40. The cooling roller 51 and the pull-down rollers 81a to 81g are conveying rollers that set the areas on both sides of the width direction of the glass plate in the conveying direction of the glass plate to convey the glass plate downward.

Hereinafter, each configuration included in the molding device 40 will be described in detail.

(2-1) Formed body The molded body 41 is provided in the overflow chamber 20. The molded body 41 forms the molten glass FG into a sheet-shaped glass plate (glass sheet SG) by overflowing the molten glass FG from the tank.

As shown in FIG. 3, the formed body 41 has a substantially pentagonal cross-sectional shape (like a wedge shape). The front end of the substantially pentagonal shape corresponds to the lower end 41 a of the molded body 41.

In addition, the molded body 41 has an inflow port 42 at the first end (refer to FIG. 4). The inflow port 42 is connected to the downstream pipe 24 described above, and the molten glass FG flowing out of the clarification device 12 flows into the molded body 41 from the inflow port 42. A groove 43 is formed in the molded body 41. The groove 43 extends in the longitudinal direction of the molded body 41. Specifically, the groove 43 extends from the first end to the second end that is the end on the opposite side of the first end. More specifically, the groove 43 extends in the left-right direction in FIG. 4. The groove 43 is formed so that it is the deepest near the inlet 42 and gradually becomes shallower as it approaches the second end. The molten glass FG flowing into the molded body 41 overflows from a pair of top portions 41b and 41b of the molded body 41, and flows down along a pair of side surfaces (surfaces) 41c and 41c of the molded body 41. Then, molten glass FG merges with the lower end part 41a of the molded object 41, and becomes glass piece SG.

At this time, the liquid phase temperature of the glass sheet SG at the lower end 41a of the molded body 41 is 1100°C or higher, and the liquid phase viscosity is 2.5×10 ⁵ poise or higher, more preferably, the liquid phase temperature is 1160°C or higher, and the liquid phase viscosity It is 1.2×10 ⁵ poise or more. Furthermore, the viscosity of the side part (the edge material, the end part) of the glass sheet SG at the lower end 41a of the molded body 41 is less than 10 ^5.7 Poise.

(2-2) Spacer parts The partition member 50 is a member that blocks the movement of heat from the overflow chamber 20 to the forming chamber 30. The spacer 50 is arranged in the vicinity of the confluence point of the molten glass FG. Furthermore, as shown in FIG. 3, the partition member 50 is arrange|positioned at the thickness direction both sides of the glass sheet SG which the molten glass FG merges at a junction point. The spacer 50 is a heat insulating material. The spacer 50 separates the upper gas atmosphere and the lower gas atmosphere of the junction point of the molten glass FG, thereby blocking the movement of heat from the upper side to the lower side of the spacer 50.

(2-3) Cooling roller (conveying roller) The cooling roller 51 is arranged in the forming chamber 30. More specifically, the cooling roller 51 is arranged directly below the spacer 50. Furthermore, the cooling roller 51 is arrange|positioned on the both sides of the thickness direction of the glass sheet SG, and is the width direction both sides of the glass sheet SG. The cooling rolls 51 arranged on both sides of the thickness direction of the glass sheet SG operate in pairs. That is, both sides (both ends in the width direction) of the glass sheet SG are clamped by two pairs of cooling rollers 51, 51, ... with a fixed force.

The cooling roll 51 is air-cooled by an air-cooling pipe passing through it. The cooling roller 51 is in contact with the side portions (offcuts, end portions) R and L of the glass sheet SG, and rapidly cools the side portions (offcuts, end portions) R and L of the glass sheet SG by heat conduction (quenching step). The viscosity of the side parts R and L of the glass sheet SG contacting the cooling roller 51 is a specific value (specifically, 10 ^9.0 poise) or more.

The cooling roller 51 is rotationally driven by a cooling roller drive motor 390 (refer to FIG. 5). The cooling roller 51 functions as a conveyance roller that cools the side portions R and L of the glass sheet SG and lowers the glass sheet SG downward.

(2-4) Temperature adjustment unit The temperature adjustment unit 60 is installed in the molding chamber 30, and is a unit for cooling the glass sheet SG to the vicinity of the slow cooling point. The temperature adjustment unit 60 has a plurality of cooling units 61 to 65. The plurality of cooling units 61 to 65 are arranged in the width direction of the glass sheet SG and the flow direction of the glass sheet SG. Specifically, the plurality of cooling units 61 to 65 include central area cooling units 61 to 63 and side cooling units 64 and 65. The central area cooling units 61 to 63 air-cool the central area CA of the glass sheet SG. Here, the central area of the glass sheet SG refers to the central portion in the width direction of the glass sheet SG, and includes the effective width of the glass sheet SG and the area near it. In other words, the central area of the glass sheet SG is the part sandwiched by the two sides (both sides, both ends) R and L of the glass sheet SG. The central area cooling units 61 to 63 are arranged at positions facing the surface of the central area CA of the glass sheet SG along the flow direction.

(2-5) Pull-down roller (conveying roller) The pull-down rollers (conveying rollers) 81a to 81g are installed in the cooling chamber 80, and lower the glass sheet SG passing through the molding chamber 30 in the flow direction of the glass sheet SG. The pull-down rollers 81a-81g are arranged inside the cooling chamber 80 with a certain interval in the flow direction. Plural pull-down rollers 81a to 81g are arranged on both sides in the thickness direction of the glass sheet SG (refer to FIG. 3) and on both sides in the width direction of the glass sheet SG (refer to FIG. 4). That is, the pull-down rollers 81a to 81g hold both sides (both sides, both ends) R and L in the width direction of the glass sheet SG with a fixed force, and both sides in the thickness direction of the glass sheet SG make the glass sheet SG descends downward.

The pull-down rollers 81a to 81g are driven by a pull-down roller drive motor 391 (see FIG. 5). In addition, the pull-down rollers 81a to 81g rotate inside with respect to the glass sheet SG. Regarding the peripheral speed of the pull-down rollers 81a to 81g, the more downstream the peripheral speed of the pull-down roller is. That is, among the plurality of pull-down rollers 81a to 81g, the peripheral speed of the pull-down roller 81a is the smallest, and the peripheral speed of the pull-down roller 81g is the largest. The pull-down rollers 81a to 81g arranged on both sides of the thickness direction of the glass sheet SG operate in pairs, and the paired pull-down rollers 81a, 81a, ... lower the glass sheet SG in the downward direction.

(2-6) Heater The heater 82 (82a-82g) is installed inside the cooling chamber 80 to adjust the temperature of the internal space of the cooling chamber 80. Specifically, plural heaters 82a to 82g are arranged in the flow direction of the glass sheet SG and the width direction of the glass sheet SG. More specifically, 7 heaters are arranged in the flow direction of the glass sheet SG, and 7 heaters are arranged in the width direction of the glass sheet. The 7 heaters arranged in the width direction are performed separately for the central area CA of the glass sheet SG and the side parts (edges, end parts) R and L of the glass sheet SG including the nip area clamped by the pull-down rollers 81a-81g Heat treatment. The heaters 82a to 82g are output controlled by the control device 500 described below. Thereby, the temperature of the gas environment near the glass sheet SG inside the cooling chamber 80 is controlled. The temperature control of the glass sheet SG is performed by controlling the temperature of the gas environment in the cooling chamber 80 by using the heaters 82a-82g. Furthermore, by temperature control, the glass sheet SG moves from the viscous region to the elastic region through the viscoelastic region. In this way, under the control of the heaters 82a to 82g, the temperature of the glass sheet SG in the cooling chamber 80 is cooled from the temperature near the slow cooling point to the temperature near the room temperature. Here, the slow cooling point is the temperature at which the viscosity becomes 10 ¹³ Poise, and here, for example, 715.0°C.

(2-7) Cutting device The cutting device 90 cuts the glass sheet SG in the cooling chamber 80 to a temperature near room temperature to a specific size. The cutting device 90 cuts the glass sheet SG at specific time intervals. Thereby, the glass sheet SG becomes a plurality of glass plates. The cutting device 90 is driven by a cutting device drive motor 392 (refer to FIG. 5). In this way, when a glass sheet is manufactured by the glass sheet manufacturing device 100, a forming step and a conveying step are performed. The forming step is to use the overflow down-draw method to form the molten glass FG into the glass sheet SG, and the conveying step is to make the width of the glass sheet The areas on both sides of the direction are clamped by a plurality of conveying roller pairs provided in the conveying direction of the glass sheet SG, and the glass sheet SG is conveyed in the downward direction. In this embodiment, the glass sheet is cooled in the transport step.

(2-8) Control device The control device 500 is composed of a CPU (Central Processing Unit, Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), hard disk, etc. Various equipment included in the manufacturing apparatus 100 are controlled. Fig. 5 is a block diagram showing an example of the configuration of the control device 500 in an embodiment.

Specifically, as shown in FIG. 5, the control device 500 receives one of various sensors (e.g., thermocouple 380, roll pressure sensor 382) or switches (e.g., main power switch 381) included in the glass plate manufacturing device 100 Signals to the temperature adjustment unit 60, heaters 82a to 82g, cooling roll drive motor 390, pull-down roll drive motor 391, cutting device drive motor 392, cooling roll position control motor 393, and pull-down roll position control motor 394a to 394g and so on for control. The cooling roller position control motor 393 is a motor that moves the position of the cooling roller 51 in order to control the position of the cooling roller 51, and the pull-down roller position control motors 394a to 394g are used to perform the position control of the following pull-down rollers 81a to 81g. A motor that moves the positions of the pull-down rollers 81a to 81g. In addition, the roll pressure sensor 382 is a sensor that measures the force of the cooling roll 51 and the pull-down rolls 81a to 81g pressing the glass sheet SG. The roll pressure sensor 382 is provided at the position of each of the cooling roll 51 and the pull-down rolls 81a to 81g.

When the control device 500 cools the glass sheet SG conveyed to the cooling chamber 80, the temperature distribution in the width direction in each position of the conveying path of the glass sheet SG becomes the target temperature profile. According to the thermoelectric Adjust the temperature of the temperature adjustment unit 60 and the heaters 82a-82g for the measurement results of the even 380. Thereby, the deformation of the wave shape of the glass sheet SG, and the strain and warpage of the glass sheet SG can be suppressed. The control device 500 further uses the cooling roller position control motor 393 and the pull-down roller position control motors 394a to 394g to perform position control of the cooling roller 51 and the pull-down rollers 81a to 81g. Hereinafter, the position control will be described.

(3) Position control of the conveying rollers (cooling roller 51, pull-down rollers 81a～81g) The cooling roll 51 and the pull-down rolls 81a to 81g are position-controlled in the thickness direction of the glass sheet SG as shown in FIGS. 6(a) to (c). Since the cooling roll 51 and the pull-down rolls 81a-81g are controlled by the same position from now on, in the following description, each pair of the cooling roll 51 and the pull-down rolls 81a-81g will be described as the first roll A1 and the second roll B1 pair. Or it is further described as a pair of the third roll A2 and the fourth roll B2. 6(a) to (c) are diagrams illustrating an example of position control performed by the control device 500.

Based on the measurement result of the roller pressure sensor 382, the control device 500 presses the glass sheet SG with a fixed force between the first roller A1 and the second roller B1 in the conveying roller pair with the first roller A1 and the second roller B1. In this way, the relative position of the first roller A1 with respect to the second roller B1 is controlled. In this control, the position of the second roller B1 is fixed. The control device 500 further compulsorily displaces the second roller B1 in the direction of the first roller A1 intermittently according to the degree of wear of the first roller A1 and the second roller B1.

Fig. 6(a) shows the pair of conveying rollers of the first roller A1 and the second roller B1 and the pair of conveying rollers of the third roller A2 and the fourth roller B2 adjacent to the conveying roller pair on the conveying path (the first ～4 rolls have the same diameter) in the initial state without abrasion. Since the conveying roller pair of the first roller A1 and the second roller B1, and the conveying roller pair of the third roller A2 and the fourth roller B2 are all configured to perform the above-mentioned position control, in Figure 6(a), due to both Since it is not worn, the conveyance path of the glass sheet SG extends linearly.

Fig. 6(b) shows a situation where the wear of the conveying roller pair is uneven, and the wear of the first roller A1 and the second roller B1 is greater than the wear of the third roller A2 and the fourth roller B2. That is, it represents a state where the diameters of the first roller A1 and the second roller B1 are smaller than the diameters of the third roller A2 and the fourth roller B2. In this case, in order that the first roller A1 is pressed with a fixed force F with respect to the glass sheet SG and the second roller B1, as shown in FIG. 6(b), compared with the third roller A2, it moves to FIG. 6( b) The position on the right side of the middle (thickness direction of the glass sheet SG). Therefore, the conveyance path of the glass sheet SG is curved between the conveyance roller pair of the 3rd roller A2 and the 4th roller B2, and the conveyance roller pair of the 1st roller A1 and the 2nd roller B1. This bending easily becomes the starting point of the fracture of the glass sheet SG. Therefore, as shown in FIG. 6(c), the control device 500 intermittently moves the second roller B1 in the direction of the first roller A1 (the thickness of the glass sheet SG) according to the degree of wear of the first roller A1 and the second roller B1. Direction) forcibly displaced. For example, when the degree of abrasion exceeds the allowable range, the second roller B1 is forcibly displaced in the direction of the first roller A1. The displacement amount of forced ground displacement is a predetermined amount. Thereby, the curve of the conveyance path which is easy to become the starting point of the breakage of the glass sheet SG can be made close to a linear shape. The first roll A1 and the second roll B1 are in an area where the temperature of the glass sheet SG is below the glass strain point. The glass strain point is the temperature of the glass sheet SG when the viscosity becomes 10 ^14.5 Poise. In the region below the glass strain point, the glass sheet SG becomes an elastic body and easily breaks with respect to deformation. Therefore, it is preferable that the degree of curvature of the conveying path is small. When the first roller A1 and the second roller B1 are in the region where the temperature of the glass sheet SG is higher than the glass strain point, the glass sheet SG is a viscous body or viscoelastic body, so even if the conveying path is bent, it is not easy to break starting point. Therefore, it is preferable that the second roller B1 is forcibly displaced toward the first roller A1 intermittently in a region where the temperature of the glass sheet SG is below the glass strain point. Therefore, the following position control (forced displacement of the displacement Δ) performed by the first roller A1 and the second roller B1 in the region where the temperature of the glass sheet SG is below the glass strain point can suppress the breakage of the glass sheet SG . In the above embodiment, the temperature of the first roll A1 and the second roll B1 is set in the region where the temperature of the glass sheet SG is below the glass strain point (only referred to as the region below the glass strain point), but according to another embodiment, it may be The area where the temperature of the glass sheet SG is higher than the strain point of the glass (only referred to as the area higher than the strain point of the glass). When the first roll A1 and the second roll B1 are in the region below the glass strain point, the glass sheet SG can be prevented from breaking. On the other hand, the first roll A1 and the second roll B1 are at a higher strain point than the glass In the case of the area, the effect of deterioration of the quality of the glass plate (strain of the glass plate) can be suppressed. Furthermore, the first roller A1 and the second roller B1 shown in FIGS. 6(a) to (c) are arranged on the downstream side of the conveying direction of the glass sheet SG compared to the third roller A2 and the fourth roller B2, but the first The first roller A1 and the second roller B1 may be provided on the upstream side in the conveying direction of the glass sheet SG compared to the third roller A2 and the fourth roller B2. Furthermore, it is preferable that the pair of conveying rollers such as the pair of the first roll A1 and the second roll B1, and the pair of the third roll A2 and the fourth roll B2 can be used for the glass sheet SG flowing down from the lower end 41a of the molded body 41 The method of linearly flowing downward from the lower end 41a vertically causes the position of the roller to forcibly shift.

In this way, the control device 500 is configured to control the first roller A1 to press the glass sheet SG with a fixed force F relative to the second roller B1 while the second roller B1 is fixed. The relative position of the first roller A1 with respect to the second roller B1, and further, according to the degree of wear of the first roller A1 and the second roller B1, intermittently force the second roller B1 to the direction of the first roller A1 by a displacement Δ Sexually displaced. Preferably, such position control is also performed for a plurality of conveying roller pairs provided in the conveying path of the glass sheet SG, but it may be performed for at least one of the plural conveying roller pairs. The plural conveying roller pairs provided along the conveying path are as described above. In order to make the tension of the glass sheet SG act in the conveying direction, it is preferable that the peripheral speed of the downstream conveying roller pair is faster in the conveying direction. Therefore, when each pair of a plurality of conveying rollers provided along the conveying path uses conveying rollers of the same diameter, the more downstream in the conveying direction, the greater the rotation speed of the conveying rollers. Therefore, the more the conveying roller pair is located on the downstream side in the conveying direction, the faster the wear. That is, the degree of abrasion between the plural conveying roller pairs is likely to be uneven, and the conveying path is likely to be bent as shown in FIG. 6(b). In Fig. 6(b) and (c), in order to make the form of wear easy to understand, it is emphasized.

In addition, the degree of abrasion of the first roller A1 and the second roller B1 can be measured with respect to the initial state of the first roller A1 or when the second roller B1 is forcibly displaced by using a position sensor not shown, for example. To judge the change of location. According to one embodiment, it is preferable that the degree of abrasion of the first roller A1 and the second roller B1 is such that the rotation center axis Ca of the first roller A1 and the second roller B1 when the second roller B1 is forcibly displaced The position of the midpoint P2 of the line segment L2 formed by connecting the rotation center axis Cb is used as the reference position, and it is obtained from the offset of the current midpoint P2 position relative to the reference position. The first roller A1 is always position-controlled so as to give a fixing force to the glass sheet SG, and as it is further worn, the first roller A1 moves toward the second roller B1 as shown in FIG. 6(b). Furthermore, the use time of the first roller A1 and the second roller B1 is accumulated, and when the accumulated time exceeds a specific time, it can be judged as further abrasion and the second roller B1 is forcibly displaced. According to one embodiment, it is preferable that the degree of abrasion of the first roller A1 and the second roller B1 is based on the glass plate using the first roller A1 and the first roller from when the second roller B1 is forcibly displaced The cumulative time of conveyance of the SG (the cumulative value of the use time of the first roller A1 and the second roller B1) is obtained. In addition, the control device 500 generates and drives the cooling roller position control motor 393 or the pull-down roller position control motors 394a to 394g such that the position of the second roller B1 is forcedly displaced by the displacement amount Δ to the side of the first roller A1. The control signal is not limited to the control device 500 forcibly performing position control of the displacement of the second roller B1. For example, the second roller B1 can be forcibly displaced to the first roller A1 side manually by the operator.

According to one embodiment, it is preferable that the control device 500 is configured to connect the rotation axis center Ca of the first roller A1 and the rotation axis center Cb of the second roller B1 after the second roller B1 is displaced The midpoint P2 (refer to Figure 6(b), (c)) of the halved line segment L2 is close to connect the rotation center Ca of the first roller A1 and the rotation axis center Cb of the second roller B1 without wear time. The second roller B1 is displaced in the manner of the midpoint P1 (refer to FIG. 6(a)) of the halved line segment L1. Bringing the center point P2 close to the center point P1 also includes making the center point P2 completely coincide with the center point P1, or be located at a certain distance apart. By displacing the second roller B1 in this way, the curvature of the conveying path of the glass sheet SG can be made smaller. Here, even if the center point P2 is made to coincide with the center point P1, the conveying path defined by the first roller A2 and the second roller B2 will not become a straight line depending on the degree of wear of the adjacent conveying roller pair. That is, the displacement amount Δ is preferably adjusted according to the degree of wear of the adjacent conveying roller pair.

Therefore, according to another embodiment, it is preferable that the control device 500 is configured to displace the second roller B1 so that the center Ca of the rotation axis of the first roller A1 after the second roller B1 is displaced and the second roller The position of the midpoint P2 of the bisecting line segment L2 formed by connecting the center of the rotation axis Cb of B1 in the extension direction of the line segment L2 is close to connect the center of the rotation axis of the third roller A2 and the center of the rotation axis of the fourth roller B2 The position of the midpoint P3 (refer to FIG. 6(c)) in the extension direction of the straight line L2 of the halved line segment. In this way, considering the degree of wear of the adjacent conveying roller pair, the displacement Δ of the second roller B1 is given to the second roller B1, so the conveying path is close to a linear shape. The positions of such midpoints P1, P2, P3 can be obtained by measuring the rotation axis centers of the first roll A1, the second roll B1, the third roll A2, and the fourth roll B2 with a position sensor or the like. Furthermore, the third roller A2 and the fourth roller B2 are conveying rollers located on the upstream side in the conveying direction with respect to the first roller A1 and the second roller B1, whereby the third roller A2 and the second roller located on the upstream side in the conveying direction The position of the glass sheet SG in the thickness direction of the 4 rolls B2 controls the position of the glass sheet SG in the thickness direction of the first roll A1 and the second roll B1. Therefore, it is easy to make the glass sheet SG extending from the lower end 41a of the molded body 41 The path becomes straight.

As mentioned above, the glass plate manufacturing method and the glass plate manufacturing apparatus of the present invention have been described in detail, but the present invention is not limited to the above-mentioned embodiments, of course, various improvements can be made without departing from the spirit of the present invention Or change.

11‧‧‧Melting device 12‧‧‧Clarification device 20‧‧‧Overflow chamber 24‧‧‧Downstream Pipe 30‧‧‧Forming chamber 40‧‧‧Forming device 41‧‧‧Form 41a‧‧‧Side 41b‧‧‧Top 41c‧‧‧Lower end 42‧‧‧Inlet 43‧‧‧Slot 50‧‧‧Spacer parts 51‧‧‧Cooling Roll 60‧‧‧Temperature adjustment unit 61～65‧‧‧Cooling unit 80a, 80b‧‧‧Insulation parts 81a～81g‧‧‧Down roller 82a～82g‧‧‧Heater 90‧‧‧Cutting device 91‧‧‧Control device 100‧‧‧Glass plate manufacturing equipment 380‧‧‧thermocouple 381‧‧‧Main power switch 382‧‧‧Roll Pressure Sensor 390‧‧‧Cooling roller drive motor 391‧‧‧Down roller drive motor 392‧‧‧Cutting device drive motor 393‧‧‧Cooling roller position control motor 394a～394g‧‧‧Motor for position control of pull-down roller 500‧‧‧Control device A1‧‧‧The first roll A2‧‧‧The third roll B1‧‧‧The second roll B2‧‧‧The 4th roll Ca‧‧‧The rotation center axis of the first roller A1 Cb‧‧‧The rotation center axis of the second roller B1 CA‧‧‧Central area F‧‧‧force L1, L2, L3‧‧‧Line segment P1, P2, P3‧‧‧midpoint R, L‧‧‧ side SG‧‧‧glass sheet S1‧‧‧Melting step S2‧‧‧Clarification steps S3‧‧‧Forming steps S4‧‧‧Cooling step S5‧‧‧Cut off step

Fig. 1 is a flowchart of a method of manufacturing a glass plate according to an embodiment. Fig. 2 is a schematic diagram showing the manufacturing device of the glass plate used in the manufacturing method of the glass plate. Fig. 3 is a schematic diagram (cross-sectional view) of the outline of the forming apparatus. Fig. 4 is a schematic diagram (side view) of the outline of the forming apparatus. Fig. 5 is a block diagram showing an example of the configuration of a control device used in a glass plate manufacturing apparatus according to an embodiment. 6(a) to (c) are diagrams for explaining an example of position control performed by the control device shown in FIG. 5.

A1‧‧‧The first roll

A2‧‧‧The third roll

B1‧‧‧The second roll

B2‧‧‧The 4th roll

Ca‧‧‧The rotation center axis of the first roller A1

Cb‧‧‧The rotation center axis of the second roller B1

F‧‧‧force

L2‧‧‧Line segment

P1, P2, P3‧‧‧midpoint

SG‧‧‧glass sheet

Claims (10)

A method for manufacturing a glass plate, characterized by having: a forming step, which uses an overflow down-draw method to shape molten glass to form a glass plate; and a conveying step, which is a step of forming the area on both sides of the glass plate in the width direction It is clamped by a plurality of conveying roller pairs arranged at different positions in the conveying direction of the glass plate, and the glass plate is conveyed downward; at least one of the plural conveying roller pairs has a first roller and a second roller In the pair of conveying rollers, the relative position of the first roller with respect to the second roller is controlled in such a manner that the first roller sandwiches the glass plate with respect to the second roller and presses with a fixed force, and further, according to the first roller The degree of abrasion of the first roller and the second roller intermittently causes the second roller to forcibly shift in the direction of the first roller. The method for manufacturing a glass plate according to claim 1, wherein the second roller is a line segment formed by connecting the center of the rotation axis of the first roller and the center of the rotation axis of the second roller after the second roller is displaced The midpoint of the division is close to the midpoint of a line segment formed by connecting the center of rotation of the first roller and the center of the rotation axis of the second roller when there is no wear. The method for manufacturing a glass plate according to claim 1, wherein when the first roller and the second roller are the conveying roller pair A, the plurality of conveying roller pairs include adjacent to the conveying roller pair A in the conveying direction The conveying roller pair B with the third roller and the fourth roller is based on the third The roller controls the relative position of the third roller with respect to the fourth roller by pressing the glass plate with a fixed force with respect to the fourth roller, so as to control the relative position of the third roller and the fourth roller according to the wear of the third roller and the fourth roller. The fourth roller is intermittently and forcibly displaced in the direction of the third roller to form the transport roller pair B, and the second roller aligns the center of the rotation axis of the first roller after the displacement with The position where the midpoint of the line segment formed by connecting the center of the rotation axis of the second roller in the extending direction of the line segment is close to connect the center of the rotation axis of the third roller to the center of the rotation axis of the fourth roller The midpoint of the halved line segment is displaced in the manner of the position in the above-mentioned extending direction. The method for manufacturing a glass plate according to claim 2, wherein when the first roller and the second roller are the conveying roller pair A, the plurality of conveying roller pairs include adjacent to the conveying roller pair A in the conveying direction The conveying roller pair B having a third roller and a fourth roller controls the third roller relative to the fourth roller by pressing the glass plate with a fixed force between the third roller and the fourth roller The relative positions of the third rollers and the fourth rollers intermittently forcibly displace the fourth rollers in the direction of the third rollers in accordance with the degree of wear of the third rollers and the fourth rollers to form the transport roller pair B, The second roller is positioned at the position in the extension direction of the line segment with the midpoint of the line segment bisected by connecting the center of the rotation axis of the first roller and the center of the rotation axis of the second roller after the displacement is close to Displacement in such a way that the midpoint of the halved line segment formed by connecting the center of the rotation axis of the third roller and the center of the rotation axis of the fourth roller to the position in the extending direction. The method for manufacturing a glass plate according to claim 3, wherein the third roller and the fourth roller are located on the upstream side in the conveying direction with respect to the first roller and the second roller. The method for manufacturing a glass plate according to claim 4, wherein the third roller and the fourth roller are located on the upstream side in the conveying direction with respect to the first roller and the second roller. The method for manufacturing a glass plate according to any one of claims 1 to 6, wherein the degree of abrasion of the first roller and the second roller is such that when the second roller is forcibly displaced The position of the midpoint of the line segment formed by connecting the rotation center axis with the rotation center axis of the second roller is the reference position, and it is determined based on the offset of the current position of the midpoint relative to the reference position. The method for manufacturing a glass plate according to any one of claims 1 to 6, wherein the degree of abrasion of the first roller and the second roller is based on when the second roller is forcibly displaced, using the first The roller and the cumulative time of the conveyance of the glass plate of the second roller are obtained. A manufacturing device for a glass sheet, characterized in that it has: a forming device that uses an overflow down-draw method to shape molten glass to shape the glass sheet; and a cooling device that sets the regions on both sides of the glass sheet in the width direction from A plurality of conveying roller pairs at different positions in the conveying direction of the glass plate are clamped, and the glass plate is conveyed downward for cooling; and a control device which controls the position of the conveying roller pair; The control device is configured as follows: in at least one conveying roller pair having a first roller and a second roller among the plurality of conveying roller pairs, the glass plate is sandwiched by the first roller relative to the second roller. The method of pressing with a fixed force controls the relative position of the first roller with respect to the second roller. Furthermore, the control device intermittently causes the second roller to intermittently according to the degree of wear of the first roller and the second roller. It is configured to forcibly shift in the direction of the above-mentioned first roller. The glass plate manufacturing apparatus of claim 9, wherein the control device controls the second roller in such a manner that the center of the rotation axis of the first roller after the second roller is displaced and the second roller The midpoint of the bisecting line segment formed by connecting the center of the rotating shaft is close to the midpoint of the bisecting line segment formed by connecting the rotation center of the first roller and the rotation axis center of the second roller when there is no wear. The way of displacement.

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