Uncoiling device and uncoiling method

Abstract

To provide an uncoiling device which can inhibit coil deviation when uncoiling a coil with a pair of cradle rolls, and to provide an uncoiling method.SOLUTION: An uncoiling device for a coil having a coil crown, includes a pair of cradle rolls which uncoils the coil placed thereon; and a parallelism adjustment mechanism which changes a difference between distances between shaft cores of the pair of cradle rolls at both sides in a width direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a coil unwinding device and a coil unwinding method using a pair of cradle rolls. [Background technology]

[0002] In a continuous processing line for steel strips (strip steel sheets), a coiled steel strip is discharged by a payoff reel, and the steel strip is continuously subjected to predetermined processing. In order to stably perform such continuous processing of steel strips, it is important to properly unwind the coil and discharge the steel strip. Therefore, various methods have been devised for unwinding the coil.

[0003] For example, in the coil unwinding method disclosed in Patent Document 1, an opener is used to open the tip of a coil attached to a payoff reel. At this time, a pressure roll, which is used to prevent bending of the unwound steel strip, is used to straighten the curl of the tip of the coil opened by the opener.

[0004] Also, for example, in the coil unwinding method disclosed in Patent Document 2, a pressure roll is used to straighten the curl of the tip of the coil that has been unwound by an opener, similar to the method disclosed in Patent Document 1. Furthermore, in the method disclosed in Patent Document 2, after unwrapping the tip of the coil, the opener moves away from the payoff reel in synchronization with the feed speed of the coil caused by the rotation of the payoff reel.

[0005] In addition, for example, in a steel strip unwinding device disclosed in Patent Document 3, after the outer periphery of the coil is pressed by a pressure roll, the pressure of the pressure roll is reduced to bring side guides into contact with both widthwise ends of the steel strip, and the steel strip is paid out from the pay-off reel. In such a case, the upward displacement of the steel strip is regulated by the pressure roll, and the widthwise displacement is regulated by the side guide, thereby stabilizing the running state of the steel strip paid out from the pay-off reel. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5212191 [Patent Document 2] Patent No. 5435121 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-266121 Summary of the Invention [Problem to be solved by the invention]

[0007] In a continuous processing line, the steel strip is usually paid off from the coil by a pay-off reel as described above, but when unwinding the coil, in order to shorten the handling time and improve throughput, the tip of the coil may be paid off before the coil is inserted into the pay-off reel. Specifically, the coil is loaded on a pair of rolls (hereinafter referred to as "cradle rolls"), and the cradle rolls are rotated to rotate the coil and unwind it.

[0008] In such cases, the rotation of the coil can cause a skew (a slight cross) between the coil and the cradle roll. This skew can then cause the coil to move axially due to the thrust force. If the coil moves and shifts on the cradle roll, it can become difficult to insert the coil into the payoff reel. Furthermore, the coil may fall over on the cradle roll, potentially causing damage to the equipment.

[0009] The main cause of coil misalignment is a faulty cradle roll equipment. However, due to its nature, faulty cradle roll equipment is difficult to correct. The causes of coil misalignment will be described in detail later.

[0010] Furthermore, in order to suppress coil slippage, it is sufficient to reduce the amount of coil rotation; however, depending on the arrangement of equipment in the continuous processing line, restrictions are imposed on the amount of steel strip discharged from the tip of the coil, and there are limits to controlling the amount of coil rotation. For example, when the distance between the coil and the equipment upstream of the continuous processing line is large, it is difficult to suppress the amount of coil rotation. In other words, suppressing coil slippage poses a potential problem in that it also leads to restrictions on the configuration of the continuous processing line.

[0011] It should be noted that all of the methods disclosed in Patent Documents 1 to 3 relate to methods for unwinding a coil inserted into a payoff reel, and are not methods for unwinding a coil before inserting it into a payoff reel. Therefore, Patent Documents 1 to 3 do not address the problem of coil misalignment on the cradle roll, and naturally do not mention any method for solving this problem.

[0012] The present invention has been made in consideration of these points, and aims to provide a coil unwinding device and a coil unwinding method that can suppress coil misalignment when unwinding a coil using a pair of cradle rolls. [Means for solving the problem]

[0013] As mentioned above, the mechanism by which coil misalignment occurs on the cradle roll is that the coil moves due to the thrust force caused by the skew between the coil and the cradle roll. However, the inventors further investigated the causes of coil misalignment and found that the influence of coil crown is significant. The presence of coil crown causes the coil and cradle roll to come into near-point contact (almost the same as one-point contact, but with a contact area that is slightly larger than the one-point contact point), reducing the contact area. This weakens the constraint on the coil by the cradle roll, causing the coil to rotate around its vertical axis (horizontal rotation), increasing the coil skew and accelerating coil misalignment.

[0014] The inventors have come to the realization that the main cause of coil misalignment is misalignment of the cradle roll parallelism (misalignment of the rotation axis), and that the skew between the coil and the cradle roll can be controlled depending on the parallelism, thereby making it possible to control the behavior of coil misalignment.The gist of the present invention is as follows. The "parallelism" of a pair of cradle rolls is defined as the absolute value of the difference in the center-to-center distance between the widthwise sides of a pair (two) of cradle rolls (work side WS, drive side DS).

[0015] The present invention is a coil unwinding device having a coil crown, characterized in that it comprises a pair of cradle rolls on which the coil is loaded and unwinds the coil, and a parallelism adjustment mechanism that changes the difference in the distance between the axes of the pair of cradle rolls on both sides in the width direction.

[0016] The coil unwinding device may further include a coil deviation measuring device that measures the amount of coil deviation from the initial position of the coil loaded on the pair of cradle rolls when the coil is unwinding, and may have a function of controlling the amount of change in the difference in the center-to-center distance on both sides of the pair of cradle rolls in the width direction based on the amount of coil deviation measured by the coil deviation measuring device.

[0017] The present invention also provides a coil unwinding method for unwinding a coil using the coil unwinding device, characterized in that the distance between the axes of the cradle roll on both sides of the width direction in the direction in which the coil moves is controlled to be relatively narrower than the distance between the axes of the cradle roll on both sides of the width direction in the opposite direction to the direction in which the coil moves.

[0018] The present invention also provides a coil unwinding method for unwinding a coil using the coil unwinding device, characterized in that the amount of change in the difference in the center-to-center distance on both sides of the width direction of the pair of cradle rolls is controlled in real time based on the amount of coil deviation measured by the coil deviation measuring device. [Effects of the Invention]

[0019] According to the present invention, the behavior of the coil misalignment can be controlled by controlling the parallelism of the pair of cradle rolls, which results in suppressing the thrust force caused by the skew between the coil and the cradle roll, thereby making it possible to suppress the coil misalignment on the cradle roll. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is an explanatory diagram showing an outline of the configuration of a continuous processing line. [Figure 2] FIG. 1 is a perspective view showing an outline of the basic configuration of a part of a coil unwinding device. [Figure 3] FIG. 10 is a graph showing the relationship between the coil crown amount and the coil misalignment amount. [Figure 4] FIG. 10 is a diagram illustrating parallelism misalignment of the cradle roll. [Figure 5] FIG. 10 is a diagram illustrating horizontal misalignment of a cradle roll. [Figure 6] FIG. 10 is a graph showing the relationship between the amount of coil misalignment and parallelism. [Figure 7] 1 is a schematic explanatory diagram of a coil unwinding device according to an embodiment of the present invention; [Figure 8] 1 is a schematic explanatory diagram of a coil unwinding device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0022] <Configuration of continuous processing line> First, the configuration of a continuous processing line in which a coil unwinding device according to this embodiment is implemented will be described with reference to Figure 1. In this embodiment, a case will be described in which the continuous processing line 1 is a cold rolling line, as an example. In the continuous processing line 1, a coil C produced in a hot rolling process is unwound, and a steel strip S is delivered, and predetermined processes such as welding and rolling are continuously performed on the steel strip S.

[0023] Fig. 1 is an explanatory diagram showing the outline of the configuration of a continuous processing line 1. As shown in Fig. 1, the continuous processing line 1 is equipped with a coil unwinding device 10, deflector rolls 11, pinch rolls 12, a leveler 13, and a welding machine 14. Note that the continuous processing line 1 is further equipped with devices such as a rolling mill downstream of the welding machine 14 in the conveying direction, but for the sake of explanation, Fig. 1 does not show the entire continuous processing line 1, but shows the configuration from the coil unwinding device 10 to the welding machine 14.

[0024] The coil unwinding device 10 unwinds the coil C and delivers the steel strip S toward the welding machine 14. The deflector roll 11 changes the direction of the steel strip S so that the steel strip S delivered from the coil C is transported to the welding machine 14. The pinch rolls 12 are provided as a pair, one above the other, and sandwich the steel strip S between them to transport it to the welding machine 14. The leveler 13 has a plurality of work rolls arranged in a staggered pattern above and below along the transport direction of the steel strip S, and corrects the shape of the steel strip S. The welding machine 14 welds the rear end of the preceding steel strip S to the front end of the following steel strip S.

[0025] <Basic configuration of coil unwinding device> Next, the basic configuration of the coil unwinding device 10 will be described with reference to Figures 1 and 2. Figure 2 is a perspective view showing an outline of the basic configuration of part of the coil unwinding device 10 (coil positioner 20).

[0026] The coil unwinding device 10 is provided with a coil positioner 20 that loads the coil C and moves it to a predetermined position, and a payoff reel 21 that pays off the steel strip S from the coil C.

[0027] The coil positioner 20 is configured to be able to move the coil C horizontally and vertically, and moves the coil C sequentially to a coil receiving position P1, a leading edge feeding position P2, and a payoff reel insertion position P3. The coil positioner 20 includes cradle rolls 30a, 30b, stands 31a, 31b, motors 32a, 32b, and a moving frame 33.

[0028] Each cradle roll 30a, 30b extends in the Z direction and is arranged side by side in the X direction. That is, the pair of cradle rolls 30a, 30b is arranged substantially parallel. Each cradle roll 30a, 30b is arranged horizontally. Each cradle roll 30a, 30b is configured to be able to load a coil C so that the axial direction of the coil C faces the Z direction. Each cradle roll 30a, 30b is configured to be rotatable, and the coil C is rotated to unwind. In the example shown in FIG. 2, the cradle rolls 30a, 30b are rotated counterclockwise, and the coil C is rotated clockwise.

[0029] In the following description, the cradle roll 30a on the upstream side (entry side) of the rotation direction of the coil C (unwinding direction of the coil C) is referred to as the upstream cradle roll 30a, and the cradle roll 30b on the downstream side (exit side) of the rotation direction of the coil C is referred to as the downstream cradle roll 30b. In the example shown in Fig. 2, the rotation direction of the coil C is clockwise, the upstream cradle roll 30a is disposed on the positive side of the X direction, and the downstream cradle roll 30b is disposed on the negative side of the X direction.

[0030] The base 31a supports the upstream cradle roll 30a. The base 31a may have any configuration. For example, the base 31a supports both ends of the central axis 34a of the upstream cradle roll 30a in the X direction, is disposed below the upstream cradle roll 30a with a gap therebetween, and extends in the Z direction. The base 31b has a similar configuration to the base 31a, and supports the central shaft 34b of the downstream cradle roll 30b.

[0031] The motor 32a is provided below the upstream cradle roll 30a and on the negative Z-direction side of the stand 31a. The motor 32a rotates the upstream cradle roll 30a via a gear (not shown). The motor 32b has a configuration similar to that of the motor 32a, and is provided below the downstream cradle roll 30b and on the negative Z-direction side of the base 31b. The motor 32b rotates the downstream cradle roll 30b.

[0032] The moving frame 33 supports the mounts 31a and 31b. The moving frame 33 is configured to be movable in the horizontal and vertical directions by a moving mechanism (not shown).

[0033] In the coil positioner 20 having the above configuration, the positive side in the Z direction is the work side (WS), and the negative side in the Z direction is the drive side (DS). The configuration of the coil unwinding device 10 (coil positioner 20) described above is a basic configuration, and it may include components with various other functions. For example, it may include a device with a function that can change the parallelism of the cradle rolls 30a, 30b, which will be described later.

[0034] <Continuous processing method> In the continuous processing line 1 having the above-described configuration, first, at the coil receiving position P1, the coil C is delivered to the coil positioner 20 and loaded onto the pair of cradle rolls 30a, 30b.

[0035] Next, the coil positioner 20 is moved to the leading end feed position P2. At the leading end feed position P2, the pair of cradle rolls 30a, 30b are rotated to rotate the coil C. As a result, the coil C is unwound and the leading end of the steel strip S is paid out.

[0036] The steel strip S unwound from the coil C passes through a deflector roll 11, a pinch roll 12, and a leveler 13, and is transported to a welding machine 14. In the welding machine 14, the leading end of the steel strip S is welded to the trailing end of the preceding steel strip S.

[0037] In the welding machine 14, while the rear end of the preceding steel strip S is being welded to the front end of the following steel strip S (the paid-out steel strip S), the coil positioner 20 is moved to the pay-off reel insertion position P3. At the pay-off reel insertion position P3, the pay-off reel 21 is inserted into the coil C by a moving mechanism (not shown). Thereafter, the steel strip S is paid out from the coil C inserted into the pay-off reel 21.

[0038] <Mechanism of coil misalignment> In the coil unwinding device 10 of the continuous processing line 1, from the time when unwinding of the coil C begins at the leading end feed position P2 until the payoff reel 21 is inserted into the coil C at the payoff reel insertion position P3, the coil C loaded on the pair of cradle rolls 30a, 30b moves approximately in the Z direction, which may cause coil misalignment on the cradle rolls 30a, 30b. The mechanism of coil misalignment will be explained below.

[0039] The main causes of the coil misalignment include (1) the coil crown of the coil C, (2) misalignment in parallelism of the cradle rolls 30a and 30b, and (3) misalignment in horizontality of the cradle rolls 30a and 30b.

[0040] (1) Coil crown of coil C The coil C transported to the continuous processing line 1, which is a cold rolling line, was previously produced in a hot rolling process. In the hot rolling process, when a steel plate is rolled with a rolling roll, the rolling roll undergoes elastic deformation, causing the thickness of the steel plate to increase in the center of the width direction and decrease at both ends. When the steel plate rolled in this way is wound into a coil, the plate crown of the steel plate overlaps, giving the coil C an outer shape like a barrel, with the coil diameter increasing in the center of the width direction and decreasing at both ends. The difference between the coil radius of this coil C at the center and the coil radius at the ends is the coil crown.

[0041] If the coil C has a coil crown, the coil C and the upstream cradle roll 30a will be in approximately point contact, reducing the contact area, and the coil C and the downstream cradle roll 30b will be in approximately point contact, reducing the contact area. This weakens the restraint of the coil C by the cradle rolls 30a and 30b. Furthermore, depending on the parallelism and horizontality of the cradle rolls 30a and 30b (described later) and the method of loading the coil C onto the cradle rolls 30a and 30b, the axial direction of the coil C may be tilted relative to the axial direction of each cradle roll 30a and 30b (hereinafter referred to as "coil tilt"). This coil tilt creates a difference in peripheral speed between the coil C and the upstream cradle roll 30a and also between the coil C and the downstream cradle roll 30b. In other words, relative slip occurs due to the difference in diameter between the contact surfaces caused by the coil crown, generating a rotational moment around the Y-axis in the coil C. Furthermore, because the restraint of the coil C by the cradle rolls 30a and 30b is weak, the coil C becomes more rotatable.

[0042] When the rotation moment is generated, the coil C moves, resulting in a skew (slight cross) between the coil C and each of the cradle rolls 30a and 30b. Then, the thrust force caused by this skew moves the coil C in the axial direction (approximately the Z direction).

[0043] The inventors conducted an FEM analysis to verify the influence of coil misalignment due to coil crown. In this analysis, the parallelism (described below) of the cradle rolls 30a and 30b was set to 4 mm and the horizontality (described below) was set to 0 (zero) mm as equipment-related disturbances that could cause coil misalignment. Figure 3 shows the results of this analysis, showing the relationship between the amount of coil crown (horizontal axis) and the amount of coil misalignment (vertical axis). Referring to Figure 3, when there was no coil crown, almost no coil misalignment occurred. In contrast, as the amount of coil crown increased, the amount of coil misalignment increased. It is presumed that the reason for the increased coil misalignment when there was coil crown is the geometric constraint of the coil C by the cradle rolls 30a and 30b, as described above. As described above, it was verified that coil misalignment occurs due to coil crown.

[0044] (2) Parallelism misalignment of the cradle rolls 30a and 30b Typically, the cradle rolls 30a and 30b are arranged parallel to one another. However, due to equipment design issues, there is a certain degree of error, and the cradle rolls 30a and 30b are not arranged perfectly parallel to one another. That is, as shown in FIG. 4, the distance Lws between the cradle rolls 30a and 30b in the X direction on the positive Z-direction side (WS side) is different from the distance Lds between the cradle rolls 30a and 30b in the X direction on the negative Z-direction side (DS side). In the example of FIG. 4, the distance Lws is greater than the distance Lds, and the cradle rolls 30a and 30b are arranged in a V-shape in plan view. In the following description, the absolute value of the difference between the distance Lws between the cradle rolls 30a and 30b on the WS side and the distance Lds between the cradle rolls 30a and 30b on the DW side is referred to as parallelism (=|Lws - Lds|). The state in which the cradle rolls 30a, 30b are parallel to each other and are not parallel to each other is called parallelism misalignment.

[0045] If there is misalignment in the parallelism of the cradle rolls 30a, 30b, skew occurs between the coil C and the cradle rolls 30a, 30b, and the thrust force caused by this skew generates a rotational moment about the Y axis in the coil C. When this rotational moment occurs, the skew between the coil C and the cradle rolls 30a, 30b is further accelerated, and the thrust force also increases. Then, the thrust force caused by this skew causes the coil C to move in the axial direction (approximately the Z direction).

[0046] (3) Horizontal misalignment of the cradle rolls 30a and 30b Typically, the cradle rolls 30a, 30b are arranged horizontally. However, due to equipment design issues, there is a certain degree of error, and the arrangement of the cradle rolls 30a, 30b is not completely horizontal. That is, as shown in FIG. 5 , with a horizontal axis passing through the center of the width of the upstream cradle roll 30a as a reference, there is a vertical distance Hws in the Y direction from the horizontal on the positive Z-direction side (WS side) of the upstream cradle roll 30a, and there is also a vertical distance Hds in the Y direction from the horizontal on the negative Z-direction side (DS side) of the upstream cradle roll 30a. In the following description, the absolute value of the difference between the vertical distance Hws on the WS side of the upstream cradle roll 30a and the vertical distance Hds on the DW side is referred to as the horizontality (=|Hws-Hds|). Similarly, for the downstream cradle roll 30b, the absolute value of the difference between the vertical distance Hws on the WS side and the vertical distance Hds on the DW side is referred to as the horizontality. Furthermore, the state in which the cradle rolls 30a and 30b are not horizontal is called horizontal misalignment.

[0047] If there is misalignment in the horizontality of each of the cradle rolls 30a, 30b, the thrust force due to gravity will cause the coil C to move in the axial direction (approximately in the Z direction).

[0048] As described above, the main causes of coil misalignment include (1) the coil crown of the coil C, (2) misalignment in parallelism of the cradle rolls 30a and 30b, and (3) misalignment in horizontality of the cradle rolls 30a and 30b. Analysis by the present inventors has revealed that the amount of coil misalignment caused by (3) misalignment in horizontality of the cradle rolls 30a and 30b is extremely small compared to the amount of coil misalignment caused by (1) the coil crown of the coil C and (2) misalignment in parallelism of the cradle rolls 30a and 30b.

[0049] Therefore, in the present invention, the following factors are considered to cause coil misalignment: (1) the coil crown of the coil C and (2) the parallelism misalignment of the cradle rolls 30a, 30b. Note that (1) the coil crown of the coil C inevitably occurs in the pre-treatment hot rolling process. Furthermore, errors in the equipment design of the cradle rolls 30a, 30b cannot be avoided, and (2) the parallelism misalignment of the cradle rolls 30a, 30b also inevitably occurs. Moreover, since the parallelism of the cradle rolls 30a, 30b increases during operation due to wear and tear on the equipment, it is difficult to control in terms of productivity and work efficiency.

[0050] <Method for preventing coil misalignment> In the present invention, (2) we focus on coil misalignment caused by misalignment in the parallelism of the cradle rolls 30a, 30b and suppress the coil misalignment. As described above, if there is misalignment in the parallelism of the cradle rolls 30a, 30b, skew occurs between the coil C and the cradle rolls 30a, 30b, and the thrust force caused by this skew generates a rotational moment about the Y axis in the coil C. When this rotational moment is generated, the skew between the coil C and the cradle rolls 30a, 30b is accelerated, and the thrust force also increases. As a result, the thrust force caused by this skew causes the coil C to move in the axial direction (approximately the Z direction).

[0051] (Relationship between parallelism and coil misalignment) The inventors conducted an FEM analysis to verify the relationship between the parallelism determined as described above and the coil misalignment. In this analysis, the parallelism of the cradle rolls 30a and 30b was set to 4 mm and the horizontality to 0 (zero) mm, as equipment-related disturbances that cause coil misalignment. The coil diameter at the center of the coil C in the sheet width direction was set to 1531 mm, and the diameter of the cradle rolls 30a and 30b was set to 350 mm. The distance between the axes of the pair of cradle rolls 30a and 30b on the WS side was set to 830 mm. The parallelism was varied in the range of 0 mm to 4 mm to verify the value of the coil misalignment.

[0052] Figure 6 shows the results of this analysis, showing the relationship between parallelism (horizontal axis) and coil misalignment (vertical axis). Referring to Figure 8, it is clear that the overall trend is that the greater the parallelism, the greater the coil misalignment. This result indicates that the behavior of coil misalignment can be controlled by adjusting and controlling the parallelism. In other words, correcting parallelism misalignment suppresses the occurrence of skew between coil C and cradle rolls 30a and 30b, and suppresses the generation of a rotational moment about the Y-axis in coil C due to the thrust force caused by this skew. Therefore, the axial movement of coil C (approximately in the Z direction) due to the thrust force caused by the skew is suppressed, and the amount of coil misalignment is reduced.

[0053] Therefore, the inventors have devised a method for correcting the misalignment of the parallelism of the cradle rolls 30a, 30b in order to suppress the rotation of the coil C about the Y-axis, which can cause the coil to shift. Specifically, the inventors have devised a method for providing the coil unwinding device 10 with a function that can change and adjust the parallelism of the cradle rolls 30a, 30b (hereinafter also simply referred to as parallelism).

[0054] (Coil unwinding device) Fig. 7 is a perspective view showing an outline of the configuration of the coil unwinding device 10 according to this embodiment when it has a function capable of changing the parallelism of the cradle rolls 30a, 30b. Fig. 8(a) is a schematic side view of the coil unwinding device 10 according to this embodiment as seen from the X direction, and Fig. 8(b) is a schematic plan view of the coil unwinding device 10 according to this embodiment as seen from the Y direction.

[0055] As shown in Figures 7 and 8, the coil unwinding device 10 according to this embodiment includes hydraulic cylinders 40a, 40b as a parallelism adjustment mechanism that can move the axial center positions of the cradle rolls 30a, 30b in the X direction. The hydraulic cylinder 40a is provided on the base 31a and moves the base 31a in the X direction together with the upstream cradle roll 30a and the motor 32a. In the example shown in Figure 7, two hydraulic cylinders 40a are provided for the base 31a, but the number of hydraulic cylinders 40a is not limited to this and may be, for example, one. The arrangement of the hydraulic cylinders 40a relative to the base 31a is also arbitrary. The hydraulic cylinder 40b has the same configuration as the hydraulic cylinder 40a, is provided on the base 31b, and moves the base 31b together with the downstream cradle roll 30b and the motor 32b in the X direction.

[0056] In this embodiment, the hydraulic cylinders 40a and 40b are configured to move both the bases 31a and 31b, but it is sufficient to move either the bases 31a or 31b, i.e., the cradle rolls 30a and 30b may be moved relatively in the X direction.

[0057] By providing hydraulic cylinders 40a, 40b as a parallelism adjustment mechanism, the parallelism can be adjusted by changing at least one of the distance Lws between the X-direction shaft centers on the positive Z-direction side (WS side) of the cradle rolls 30a, 30b described above with reference to FIG. 4 and the distance Lds between the X-direction shaft centers on the negative Z-direction side (DS side) of the cradle rolls 30a, 30b.

[0058] As shown in the figure, the coil unwinding device 10 may also include a distance meter 50 as a coil misalignment measurement device that measures the amount of misalignment of the coil C from the side (e.g., the positive direction of the Z axis). The distance meter 50 may be disposed or configured as desired, and may, for example, be configured to measure the distance between the distance meter 50 and a predetermined position of the coil C using a camera function, thereby measuring the amount of misalignment as needed. The hydraulic cylinders 40a, 40b may be configured to determine the amount of parallelism adjustment (the amount of change in the difference in the center-to-center distance) based on the measurement results of the distance meter 50, and adjust the parallelism. Here, the amount of coil misalignment may be defined as the absolute value of the amount of axial movement of the coil C from the position of the coil C when it was loaded on the pair of cradle rolls 30a, 30b, and the WS side may be defined as a positive value and the DS side as a negative value.

[0059] According to the inventor's investigations, when the coil C moves from its position when loaded on the coil unwinding device 10 to the positive side in the Z direction (WS side), coil misalignment can be suppressed by controlling the X-direction axis center distance Lws on the WS side to be narrower than the X-direction axis center distance Lds on the DS side. Also, when the coil C moves from its position when loaded on the coil unwinding device 10 to the negative side in the Z direction (DS side), coil misalignment can be suppressed by controlling the X-direction axis center distance Lws on the WS side to be wider than the X-direction axis center distance Lds on the DS side.

[0060] For example, after the start of unwinding the coil, when it is determined that the coil misalignment exceeds a predetermined threshold and falls outside the allowable operational range, the parallelism may be adjusted. The parallelism may be adjusted so that the coil misalignment decreases by a predetermined small value (e.g., 1 mm). The parallelism may be adjusted based on the coil misalignment measured by the distance meter 50, or may be adjusted automatically. The parallelism may be adjusted until the coil misalignment falls within a predetermined threshold (within the allowable operational range) and terminated when the coil misalignment falls within the predetermined threshold. The threshold for the coil misalignment may be set appropriately depending on the operational conditions, etc. A specific example of control will be described later in the examples.

[0061] (How to unwind the coil) As shown in FIG. 1, in the coil unwinding device 10, first, at the coil receiving position P1, the coil C is delivered to the coil positioner 20 and loaded onto a pair of cradle rolls 30a, 30b.

[0062] Next, the coil positioner 20 is moved to the leading end feed position P2. At the leading end feed position P2, the pair of cradle rolls 30a, 30b are rotated to rotate the coil C. As a result, the coil C is unwound and the leading end of the steel strip S is paid out.

[0063] In the coil unwinding method according to this embodiment, the parallelism of the pair of cradle rolls 30a, 30b is adjusted when the coil is unwound as described above. This corrects parallelism misalignment and reduces skew between the coil C and the cradle rolls 30a, 30b. This also prevents a rotational moment from being generated about the Y-axis in the coil C due to the thrust force caused by the skew. This prevents the coil C from moving in the axial direction (approximately in the Z direction) due to the thrust force caused by the skew, reducing the amount of coil misalignment.

[0064] Next, the coil positioner 20 is moved to the payoff reel insertion position P3. At the payoff reel insertion position P3, the payoff reel 21 is inserted into the coil C by a moving mechanism (not shown). Thereafter, the steel strip S is paid out from the coil C inserted into the payoff reel 21.

[0065] <Action and effect> According to the above embodiment, even if there is a parallelism misalignment between the cradle rolls 30a and 30b when unwinding the coil C, adjusting the parallelism can prevent skew between the coil C and the cradle rolls 30a and 30b, and can prevent a rotation moment about the Y axis from being generated in the coil C due to the thrust force caused by the skew. This also prevents the coil C from moving in the axial direction (approximately the Z direction) due to the thrust force caused by the skew, thereby preventing coil misalignment.

[0066] As explained with reference to Fig. 6, there is a certain correlation between parallelism and the amount of coil misalignment, and the behavior of coil misalignment can be controlled by controlling the parallelism of the cradle rolls. That is, by measuring the amount of coil misalignment and adjusting the parallelism based on the measurement results, appropriate adjustments can be made so that the amount of coil misalignment falls within a predetermined threshold range (operational tolerance range).

[0067] While one embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0068] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects. [Example]

[0069] An experiment was conducted to verify the coil misalignment suppression effect of the present invention. This verification was carried out using a coil loaded on a pair of cradle rolls, similar to the coil positioner shown in Figure 7.

[0070] In this verification, the maximum coil misalignment amount was measured when 20m of each of ten coils with outer diameters of 1.2m to 2.0m and widths of 1.0m to 1.6m was unwound. The coil misalignment amount was measured as the amount of axial movement of the coil from its initial position when it was loaded onto a pair of cradle rolls, with the WS side being a positive value and the DS side being a negative value.

[0071] The diameter of each cradle roll is 350 mm, and the roll width (body length) is 1 m. The distance between the axes of the WS side of the pair of cradle rolls is 830 mm. The pair of cradle rolls are arranged non-parallel (V-shaped), causing parallelism misalignment. In this case, it would be sufficient to determine the initial misalignment of the cradle roll parallelism, but measuring it for each coil each time is difficult from an operational standpoint (workload and equipment stoppages).

[0072] Example 1 In Example 1, when unwinding the coil, the parallelism was adjusted while observing the amount of coil misalignment when the coil moved approximately 25 mm from the initial position toward the WS side. Specifically, the adjustment was made in 1 mm increments so that the distance between the axes in the X direction on the WS side (Lws in FIG. 4) became narrower than the distance between the axes in the X direction on the DS side (Lds in FIG. 4).

[0073] As a result, the direction of the coil displacement was toward the DS side, and the final coil displacement amount was -5 mm (5 mm toward the DS side from the initial position).

[0074] Similarly, when unwinding another coil, when the coil moved approximately 25 mm toward the WS side from its initial position, a parallelism adjustment was made to narrow the center-to-center distance in the X direction on the WS side by 4 mm. As a result, the coil moved toward the DS side and exceeded -25 mm from its initial position (25 mm toward the DS side from its initial position), so a parallelism adjustment was made to widen the center-to-center distance in the X direction on the WS side by 3 mm. As a result of this parallelism adjustment, the coil misalignment ultimately became almost 0 mm.

[0075] From the above verification, it was confirmed that parallelism misalignment can be corrected by adjusting the parallelism and that coil misalignment can be suppressed. Furthermore, when coil misalignment occurs, it was confirmed that coil misalignment can be suppressed by controlling the distance between the axes of the cradle rolls in the width direction in the direction in which the coil moves to be relatively narrower than the distance between the axes of the cradle rolls in the width direction on the opposite side to the direction in which the coil moves.

[0076] Example 2 In Example 2, when unwinding the coil, the amount of coil misalignment was measured as needed using a distance meter, and when the coil moved from its initial position to the WS side, control was performed to adjust the parallelism so that the X-direction axis distance on the WS side became narrower than the X-direction axis distance on the DS side. On the other hand, when the coil moved from its initial position to the DS side, control was performed to adjust the parallelism so that the X-direction axis distance on the WS side became wider than the X-direction axis distance on the DS side. By performing this kind of automatic control (real-time control), the coil misalignment during unwinding was kept within ±5 mm.

[0077] From the above verification, it was confirmed that adjusting the parallelism corrects the parallelism misalignment and suppresses the coil misalignment. In addition, it was confirmed that by performing the adjustment by automatic control, it is possible to unwind the coil while appropriately suppressing the coil misalignment. [Industrial Applicability]

[0078] The present invention is useful when unwinding a coil using a pair of cradle rolls. [Explanation of symbols]

[0079] 1 Continuous processing line 10 Coil unwinding device 11 Deflector roll 12 Pinch Roll 13 Leveller 14 Welding machine 20 Coil Positioner 21 Payoff Reel 30a Upstream cradle roll 30b Downstream cradle roll 31a, 31b Mounting stand 32a, 32b motor 33 Moving Frame 34a, 34b center axis 40a, 40b Hydraulic cylinder 50 rangefinder C coil P1 Coil receiving position P2 Lead edge feed position P3 Payoff reel insertion position S steel strip

Claims

1. 1. An unwinding device for a coil having a coil crown, comprising: a pair of cradle rolls that load the coil and unwind the coil; a parallelism adjustment mechanism that changes the difference in the distance between the axes of the pair of cradle rolls in the width direction.

2. The coil misalignment measuring device further includes a coil misalignment measuring device for measuring a coil misalignment amount from an initial position of the coil loaded on the pair of cradle rolls when the coil is unwound, The coil unwinding device according to claim 1, characterized in that it has a function of controlling the amount of change in the difference in the center-to-center distance between both sides of the pair of cradle rolls in the width direction based on the amount of coil deviation measured by the coil deviation measuring device.

3. A coil unwinding method for unwinding a coil using the coil unwinding device according to claim 1 or 2, comprising: A coil unwinding method characterized by controlling the distance between the axes of the cradle roll on both sides in the width direction in which the coil moves to be relatively narrower than the distance between the axes of the cradle roll on the opposite side to the direction in which the coil moves.

4. A coil unwinding method for unwinding a coil using the coil unwinding device according to claim 2, A coil unwinding method characterized in that the amount of change in the difference in the center-to-center distance between both sides of the pair of cradle rolls in the width direction is controlled in real time based on the amount of coil deviation measured by the coil deviation measuring device.

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