Control method of uncoiling device

Abstract

To provide a control method of an uncoiling device which can inhibit coil deviation when uncoiling a coil with a pair of cradle rolls.SOLUTION: A regression equation is created using, as explanatory variables, a coil crown quantity of a coil, a coil outer diameter in a center part in a width direction of the coil, a friction coefficient of a cradle roll against the coil, a parallelism which is a difference between a distance between shaft cores of the pair of cradle rolls at one end in the width direction and a distance between the shaft cores at the other end in the width direction, and a levelness which is a difference between a vertical distance of the cradle roll from a horizontal direction at the one end in the width direction and a vertical distance from the horizontal direction at the other end in the width direction and using, as an objective variable, a coil deviation amount which is a distance that the coil moves from an initial position of the coil placed on the pair of cradle rolls when the coil is uncoiled. Then, the parallelism and the levelness are controlled so that a value calculated using the regression equation becomes equal to or lower than an allowable value.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a method for managing a coil unwinding device 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 poor cradle roll equipment. Normally, cradle rolls are arranged parallel and horizontally, but there is a certain degree of error in these parallelism and horizontality due to equipment design issues. These errors in parallelism and horizontality can cause coil misalignment. 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 the above points, and aims to provide a method for managing a coil unwinding device 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] In order to suppress coil misalignment, it is important to manage the coil unwinding device, and in particular, thorough management of the cradle roll is necessary. Therefore, the inventors created a regression equation using the amount of coil misalignment as the objective variable, and were able to set management standards for the unwinding device (cradle roll) through calculation. The gist of the present invention is as follows.

[0015] The present invention provides a method for managing an unwinding device for a coil having a coil crown, the unwinding device comprising a pair of cradle rolls that load the coil and unwind the coil, and using as explanatory variables the coil crown amount of the coil, the coil outer diameter at the widthwise center of the coil, the friction coefficient of the cradle rolls with respect to the coil, the parallelism which is the difference between the axis center distance at one widthwise end side of the pair of cradle rolls and the axis center distance at the other widthwise end side, and the horizontality which is the difference between the vertical distance from the horizontal direction at one widthwise end side of the cradle rolls and the vertical distance from the horizontal direction at the other widthwise end side, and creating a regression equation in which the coil deviation amount of the coil that has moved from the initial position of the coil loaded on the pair of cradle rolls when the coil is unwinding is used as a response variable, and managing the parallelism and the horizontality so that the regression equation is within an allowable value.

[0016] In the method for managing a coil unwinding device, the regression equation may be expressed by the following equation (1). M=K(Cr,φ,μ,ΔH,ΔV)=α×J(Cr,φ,μ,ΔH,ΔV)+β ···(1) however, J(Cr,φ,μ,ΔH,ΔV)=V(Cr)·W(φ)·X(μ)·Y(ΔH)·Z(ΔV), M: the coil deviation amount, α and β: adjustment coefficients, Cr: the coil crown amount, φ: outer diameter of the coil, μ: the friction coefficient, ΔH: the parallelism, ΔV: horizontality, V(Cr): A regression equation of the coil crown amount relative to the coil deviation amount, W(φ): A regression equation of the coil outer diameter with respect to the coil deviation amount, X(μ): regression equation of the friction coefficient with respect to the coil deviation amount, Y(ΔH): regression equation of the parallelism with respect to the coil deviation amount, Z(ΔV): Regression equation of the horizontality with respect to the coil deviation. [Effects of the Invention]

[0017] According to the present invention, a regression equation is created in which the coil crown amount, coil outer diameter, friction coefficient of the cradle roll, parallelism of the pair of cradle rolls, and horizontality of the cradle rolls are used as explanatory variables, and the coil misalignment amount is used as the objective variable.The parallelism and horizontality of the cradle rolls can then be controlled so that the coil misalignment amount in the regression equation is within an allowable value.In other words, the control standards for the unwinding device (cradle roll) can be set by calculation, making it possible to suppress coil misalignment. [Brief explanation of the drawings]

[0018] [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 a partial configuration of a coil unwinding device (coil positioner). [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 graph showing the relationship between the parallelism of the cradle rolls and the amount of coil misalignment. [Figure 6] FIG. 10 is a diagram illustrating horizontal misalignment of a cradle roll. [Figure 7] 1 is a schematic explanatory diagram of a coil unwinding device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] <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.

[0021] 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.

[0022] 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.

[0023] <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 a partial configuration of the coil unwinding device 10 (coil positioner 20).

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The frame 31a supports the upstream cradle roll 30a. The frame 31a may have any configuration. For example, the frame 31a supports both ends of the central axis 34a of the upstream cradle roll 30a in the Z 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.

[0029] 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.

[0030] 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).

[0031] In the coil positioner 20 having the above configuration, the positive side in the Z direction is the working side (WS: work side), and the negative side in the Z direction is the driving side (DS: drive side). 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 capable of changing the parallelism of the cradle rolls 30a, 30b (described later), or it may include a device capable of changing the horizontality of the cradle rolls 30a, 30b.

[0032] <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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] <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.

[0037] 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.

[0038] (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.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] (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.

[0043] 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).

[0044] The inventors conducted an FEM analysis to verify the influence of coil misalignment due to parallelism misalignment. In this analysis, the parallelism of the cradle rolls 30a, 30b was set to 4 mm, and the horizontality (described later) was set to 0 (zero) mm, as equipment-related disturbances that cause coil misalignment. Figure 5 shows the results of this analysis, illustrating the relationship between parallelism (horizontal axis) and coil misalignment amount (vertical axis). Referring to Figure 5, the overall trend is that the coil misalignment amount increases as the parallelism increases. As described above, it was verified that coil misalignment occurs due to parallelism misalignment.

[0045] (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. 6 , with a horizontal axis passing through the center of the width direction 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.

[0046] 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).

[0047] As described above, the main causes of coil misalignment include (1) the coil crown of the coil C, (2) parallelism misalignment of the cradle rolls 30a and 30b, and (3) horizontality misalignment of the cradle rolls 30a and 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 and 30b cannot be avoided, and (2) parallelism misalignment of the cradle rolls 30a and 30b and (3) horizontality misalignment of the cradle rolls 30a and 30b also inevitably occur. Furthermore, since the parallelism and horizontality of the cradle rolls 30a and 30b increase during operation due to wear and tear on the equipment, it is important to manage them in terms of productivity and work efficiency.

[0048] <Coil unwinding device management method> In order to suppress coil misalignment, it is important to manage the coil unwinding device 10, and in particular, it is necessary to thoroughly manage the cradle rolls 30a, 30b. In the present invention, a regression equation is created in which the coil crown amount, coil outer diameter, friction coefficient of the cradle rolls 30a, 30b, parallelism of the cradle rolls 30a, 30b, and levelness of the cradle rolls 30a, 30b are used as explanatory variables, and the coil misalignment amount is used as the response variable, and management standards for the coil unwinding device 10 (cradle rolls 30a, 30b) are set by calculation.

[0049] The regression equation (1) was derived based on the experimental results using the continuous processing line 1 and the analytical results obtained by FEM analysis, and is expressed as the following equation (1). M=K(Cr,φ,μ,ΔH,ΔV)=α×J(Cr,φ,μ,ΔH,ΔV)+β ···(1) however, J(Cr,φ,μ,ΔH,ΔV)=V(Cr)·W(φ)·X(μ)·Y(ΔH)·Z(ΔV), M: Coil deviation (mm), α: adjustment coefficient (mm), β: adjustment coefficient (mm), Cr: Coil crown amount of coil C (μm), φ: outer diameter of coil C at the center in the width direction (mm), μ: coefficient of friction of the cradle rolls 30a and 30b against the coil C (dimensionless), ΔH: parallelism of the cradle rolls 30a and 30b (mm), ΔV: horizontality of the cradle rolls 30a and 30b (mm), V(Cr): Regression equation (dimensionless) of coil crown amount Cr against coil misalignment amount M. W(φ): Regression equation (dimensionless) of coil outer diameter φ against coil misalignment amount M. X(μ): Regression equation (dimensionless) of friction coefficient μ against coil displacement M, Y(ΔH): Regression equation (dimensionless) of parallelism ΔH against coil misalignment M, Z(ΔV): Regression formula (dimensionless) of horizontality ΔV against coil deviation M.

[0050] The objective variable of the regression equation (1) is the coil deviation amount M. That is, the regression equation (1) predicts the coil deviation amount M. The coil deviation amount M is the amount of axial movement of the coil C from the position (initial position) of the coil C when the coil C is loaded on the pair of cradle rolls 30a, 30b.

[0051] As mentioned above, the main causes of coil misalignment include the coil crown of the coil C, parallelism misalignment of the cradle rolls 30a and 30b, and horizontality misalignment of the cradle rolls 30a and 30b. Therefore, the explanatory variables of regression equation (1) include the coil crown amount Cr, the parallelism ΔH of the cradle rolls 30a and 30b, and the horizontality ΔV of the cradle rolls 30a and 30b.

[0052] Furthermore, the inventors' investigations have revealed that the coil slippage amount M is also affected by the coil outer diameter φ at the center of the coil C in the width direction and the friction coefficient μ of the cradle rolls 30a, 30b with respect to the coil C. That is, when the coil outer diameter φ is large, the skew of the coil C increases, and the coil slippage amount M increases. Furthermore, when the friction coefficient μ is small, the constraint of the coil C by the cradle rolls 30a, 30b weakens, and therefore the skew of the coil C increases, and the coil slippage amount M increases. For this reason, the explanatory variables of regression equation (1) include the coil outer diameter φ and the friction coefficient μ of the cradle rolls 30a, 30b.

[0053] In regression equation (1), J(Cr, φ, μ, ΔH, ΔV) is the product of the regression equations V(Cr), W(φ), X(μ), Y(ΔH), and Z(ΔV) for the explanatory variables Cr, φ, μ, ΔH, and ΔV for the coil misalignment amount M. Each regression equation V(Cr), W(φ), X(μ), Y(ΔH), and Z(ΔV) is derived by performing FEM analysis and varying the explanatory variables: coil crown amount Cr, coil outer diameter φ, friction coefficient μ, parallelism ΔH, and horizontality ΔV. For example, when deriving regression equation V(Cr), the coil crown amount Cr is varied while the other explanatory variables φ, μ, ΔH, and ΔV are held constant.

[0054] In the regression equation (1), α and β are adjustment coefficients (influence coefficients) that can be found by performing FEM analysis. Note that the regression equations V(Cr), W(φ), X(μ), Y(ΔH), and Z(ΔV) are all non-dimensional, and the adjustment coefficients α and β have the same dimension as the coil misalignment, in mm.

[0055] As described above, the regression equation (1) of the coil deviation amount M is created. When managing the coil unwinding device 10, the parallelism and horizontality of the cradle rolls 30a, 30b are managed so that the coil deviation amount M calculated from the regression equation (1) is within the allowable value.

[0056] By controlling the parallelism of the cradle rolls 30a, 30b, parallelism misalignment can be suppressed. In this case, the occurrence of skew between the coil C and the cradle rolls 30a, 30b is suppressed, and the occurrence of a rotation moment about the Y axis in the coil C due to the thrust force caused by the skew can be suppressed. As a result, the movement of the coil C in the axial direction (approximately the Z direction) due to the thrust force caused by the skew is suppressed, and the amount of coil misalignment can be reduced.

[0057] By controlling the horizontality of the cradle rolls 30a, 30b, horizontal misalignment can be suppressed. In this case, it is possible to prevent the coil C from being subjected to a rotational moment about the Y-axis due to the thrust force caused by gravity. As a result, the coil C is prevented from moving in the axial direction (approximately the Z direction) due to the thrust force caused by gravity, and the amount of coil misalignment can be reduced.

[0058] The parallelism and horizontality of the cradle rolls 30a, 30b can be controlled by any method, and may be controlled, for example, by using hydraulic cylinders 40a, 40b as a parallelism adjustment mechanism (to be described later) and hydraulic cylinders 41a, 41b as a horizontality adjustment mechanism (to be described later) provided in the coil unwinding device 10. The parallelism and horizontality of the cradle rolls 30a, 30b may also be adjusted in advance using shims or the like.

[0059] (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, which has a function capable of changing and adjusting the parallelism and horizontality of the cradle rolls 30a, 30b.

[0060] As shown in FIG. 7, the coil unwinding device 10 includes hydraulic cylinders 40a and 40b as a parallelism adjusting mechanism that can move the axial center positions of the cradle rolls 30a and 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 Fig. 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. Furthermore, 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.

[0061] 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.

[0062] 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.

[0063] The coil unwinding device 10 also includes hydraulic cylinders 41a and 41b as a levelness adjusting mechanism that can move the axial center positions of the cradle rolls 30a and 30b in the Y direction. The hydraulic cylinder 41a is provided on the base 31a and moves the central shaft 34a of the upstream cradle roll 30a in the Y direction. In the example shown in Fig. 7, one hydraulic cylinder 41a is provided at one end of the central shaft 34a, but the number of hydraulic cylinders 41a is not limited to this, and for example, two hydraulic cylinders 41a may be provided at both ends of the central shaft 34a. Furthermore, the arrangement of the hydraulic cylinders 41a on the base 31a is also arbitrary. The hydraulic cylinder 41b has the same configuration as the hydraulic cylinder 41a, is provided on the base 31b, and moves the central shaft 34b of the downstream cradle roll 30b in the Y direction.

[0064] By providing hydraulic cylinders 41a and 41b as a levelness adjustment mechanism, the levelness can be adjusted by changing at least one of the vertical distance Hws in the Y direction on the positive Z-direction side (WS side) of the cradle rolls 30a and 30b described above with reference to Figure 6 and the vertical distance Hds in the Y direction on the negative Z-direction side (DS side) of the cradle rolls 30a and 30b.

[0065] <Action and effect> According to the above embodiment, a regression equation (1) is created in which the coil crown amount Cr, the coil outer diameter φ, the friction coefficient μ, the parallelism ΔH, and the horizontality ΔV are used as explanatory variables and the coil deviation amount M is used as a response variable, and the parallelism and horizontality of the cradle rolls 30a, 30b can be controlled so that the coil deviation amount M calculated from the regression equation (1) is equal to or less than an allowable value. By controlling the parallelism and horizontality of the cradle rolls 30a, 30b in this manner, parallelism misalignment and horizontality misalignment can be suppressed, and coil deviation caused by the bobbin effect between the cradle rolls 30a, 30b can be suppressed.

[0066] Furthermore, in this embodiment, the management criteria for the cradle rolls 30a, 30b can be set by calculation using regression equation (1). For example, calculating the parallelism and horizontality of the cradle rolls 30a, 30b by performing FEM analysis takes a significant amount of time, whereas using regression equation (1) as in this embodiment makes it possible to calculate the parallelism and horizontality of the cradle rolls 30a, 30b in a short time. Therefore, the management criteria for the cradle rolls 30a, 30b (coil unwinding device 10) can be set in a simple manner.

[0067] Note that the regression equation (1) of the coil deviation amount M is not limited to the above equation (1) and can be created arbitrarily. For example, if it is determined that the coil deviation amount caused by the horizontal misalignment of the cradle rolls 30a, 30b is small compared to the coil deviation amount caused by other factors (explanatory variables), the horizontality ΔV of the cradle rolls 30a, 30b may be omitted from the explanatory variables of the regression equation (1), and the regression equation Z(ΔV) for the horizontality ΔV may also be omitted.

[0068] 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.

[0069] 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 would be apparent to a person skilled in the art from the description of this specification, in addition to or in place of the above-described effects. [Example]

[0070] To verify the coil misalignment suppression effect of the present invention, experiments and FEM analysis were conducted. This verification was carried out using a coil loaded on a pair of cradle rolls, similar to the coil positioner shown in Figure 7.

[0071] In this verification experiment, the maximum coil misalignment amount was measured when 20 m of each of ten coils with outer diameters of 1.2 m to 2.0 m and widths of 1.0 m to 1.6 m was unwound. The coil misalignment amount was measured as the absolute value of the amount of axial movement of the coil from the initial position of the coil when it was loaded onto a pair of cradle rolls. The crown of a coil with a width of 1.5 m was measured to be 3 mm.

[0072] In this verification experiment, the diameter of each cradle roll was 350 mm, and the roll width (body length) was 1 m. The distance between the axes of the WS side of the pair of cradle rolls was 830 mm. The distance between the axes of the WS side ends of the pair of cradle rolls was 4 mm greater than the distance between the axes of the DS side ends. In other words, the pair of cradle rolls were arranged non-parallel (in a V-shape), resulting in parallelism misalignment.

[0073] Meanwhile, in this verification, FEM analysis was performed to derive the regression equation (1) of the following equation (1): Note that the following equation (1) is the same as the equation (1) in the above embodiment. M=K(Cr,φ,μ,ΔH,ΔV)=α×J(Cr,φ,μ,ΔH,ΔV)+β ···(1) However, J(Cr,φ,μ,ΔH,ΔV)=V(Cr)·W(φ)·X(μ)·Y(ΔH)·Z(ΔV).

[0074] In the FEM analysis, a model was created in which a cylinder simulating a coil was placed on a pair of cradle rolls as shown in Figure 7, and the coil was rotated by rotating the cradle rolls. Contact between the cradle rolls and the coil was defined as Coulomb friction. Then, the coil crown amount Cr, coil outer diameter φ, friction coefficient μ, parallelism ΔH, and horizontality ΔV were changed to determine the effect on coil misalignment amount M. Furthermore, regression equations V(Cr), W(φ), X(μ), Y(ΔH), and Z(ΔV) were derived for the relationship between the determined coil misalignment amount M and the coil crown amount Cr, coil outer diameter φ, friction coefficient μ, parallelism ΔH, and horizontality ΔV.

[0075] The regression equations V(Cr), W(φ), X(μ), Y(ΔH), and Z(ΔV) derived by FEM analysis are expressed by the following equations (2) to (6), respectively. Note that, since the influence of the cradle roll horizontality ΔV on the coil deviation amount M was smaller than the influence of other factors (explanatory variables Cr, φ, μ, ΔH), Z(ΔV) was set to 1 in this verification. V(Cr)=0.0047Cr 3 -0.0894Cr 2 +0.5656Cr (2) W(φ)=-5.8×10 -7 ×φ 2 +2.5×10 -3 ×φ-1.6 (3) X(μ)=0.3345ln(μ)+1.6907 ···(4) Y(ΔH)=0.7077ln(ΔH+0.0915)+1.69 ···(5) Z(ΔV)=1 (6)

[0076] The experimental results (coil misalignment) measured in the above experiment were compared with the analytical results (J(Cr, φ, μ, ΔH, ΔV)) obtained by FEM analysis, and the adjustment coefficients α and β in the regression equation (1) were derived as follows. α=124.528 β=-8.4272

[0077] In this verification, the regression equation (1) created as described above was used to determine the control standard for keeping the coil misalignment amount M at 50 mm or less, which is the allowable value. As a result, the cradle roll parallelism ΔH was 0.4 mm or less. Then, using this control standard and under the same coil and cradle roll conditions as in the above experiment, 100 coils were unwound and threaded, and the maximum coil misalignment amount was 50 mm. Therefore, it was confirmed that by using regression equation (1) to set the control standard for the coil unwinding device (cradle roll), it is possible to keep the coil misalignment amount below the allowable value. [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 41a, 41b Hydraulic cylinder C coil P1 Coil receiving position P2 Lead edge feed position P3 Payoff reel insertion position S steel strip

Claims

1. 1. A method for managing an unwinding device for a coil having a coil crown, comprising: the unwinding device includes a pair of cradle rolls that load the coil and unwind the coil; a coil crown amount of the coil; the outer diameter of the coil at the center in the width direction of the coil; the coefficient of friction of the cradle roll against the coil; Parallelism, which is the difference between the center-to-center distance between one end of the pair of cradle rolls in the width direction and the center-to-center distance between the other end of the pair of cradle rolls in the width direction; A horizontality, which is a difference between a vertical distance from the horizontal direction at one end side of the width direction of the cradle roll and a vertical distance from the horizontal direction at the other end side of the width direction, is used as an explanatory variable, a regression equation is created in which the amount of coil deviation of the coil from the initial position of the coil loaded on the pair of cradle rolls when the coil is unwound is used as a response variable; A method for managing a coil unwinding device, characterized in that the parallelism and the horizontality are managed so that the regression equation is equal to or less than an allowable value.

2. 2. The method for managing a coil unwinding device according to claim 1, wherein the regression equation can be expressed by the following equation (1): M=K (Cr, φ, μ, ΔH, ΔV) = α×J (Cr, φ, μ, ΔH, ΔV) + β ... (1) however, J (Cr, φ, μ, ΔH, ΔV) = V (Cr)・W(φ)・X(μ)・Y(ΔH)・Z(ΔV), M: the coil deviation amount, α and β: adjustment coefficients, Cr: the coil crown amount, φ: outer diameter of the coil, μ: the friction coefficient, ΔH: the parallelism, ΔV: horizontality, V(Cr): regression equation of the coil crown amount with respect to the coil deviation amount, W(φ): regression equation of the coil outer diameter with respect to the coil deviation amount, X(μ): regression equation of the friction coefficient with respect to the coil deviation amount, Y(ΔH): regression equation of the parallelism with respect to the coil deviation amount, Z(ΔV): A regression equation of the horizontality with respect to the coil deviation amount.

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