CONTROL DEVICE FOR CONTROLLING ROLLING DEVICE, ROLLING FACILITY, AND METHOD FOR CONTROLLING ROLLING DEVICE

Abstract

 A control device for a rolling apparatus is a control device for controlling a rolling apparatus including a pair of mill rolls for rolling a metal strip, an unwinder for unwinding the strip toward the pair of mill rolls, and a winder for winding the strip rolled by the pair of mill rolls, including a rotation control unit for controlling rotation of the mill rolls, a velocity acquisition unit configured to acquire velocity of the strip between the unwinder and the mill rolls, and a separation detection unit configured to detect separation of a tail end of the strip from the unwinder. The rotation control unit is configured to stop the rotation of the pair of mill rolls, based on a separation timing which is a timing when the separation of the tail end from the unwinder is detected by the separation detection unit and the velocity of the strip acquired by the velocity acquisition unit.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a control device for a rolling apparatus, a rolling facility, and a control method for the rolling apparatus.

BACKGROUND

[0002] A reverse-type rolling apparatus is known, which is configured to reciprocate and roll a metal plate passed between a pair of mill rolls.

[0003] Patent Document 1 discloses a reverse-type rolling apparatus which includes a rolling stand with a mill roll, and two reels (an unwinder and a winder) disposed in front and behind the rolling stand. In this rolling apparatus, in a process of rolling in the rolling stand a rolled material unwound from the first reel and winding the rolled material with the second reel (rolling pass), the rolling apparatus is stopped once a tail end of the rolled material separating from the first reel reaches an exit side of the rolling stand and rolling in a next pass (a process of rolling in the rolling stand the rolled material unwound from the second reel and winding the rolled material with the first reel) is started.

Citation List

Patent Literature

[0004] Patent Document 1: JP2000-202503A

SUMMARY

Technical Problem

[0005] As in the reverse-type rolling apparatus described in Patent Document 1, by continuing rolling even after the tail end of a strip (rolled material) separates from the unwinder, yield can be improved compared to a case where rolling is performed while maintaining a state where a tail end portion of the strip is gripped by the unwinder. Meanwhile, time is required to accurately stop the tail end of the strip unwound from the unwinder at a position suitable for the start of rolling in the next pass. Further, after the tail end of the strip is stopped, at the start of rolling in the next pass, it is difficult to smoothly pass a head end of the strip (a tail end in a previous pass) through a deflector roll, etc. disposed between the unwinder and the mill roll, which may result in a loss of time.

[0006] In view of the above, an object of at least one embodiment of the present invention is to provide a control device for a rolling apparatus, a rolling facility, and a control method for the rolling apparatus, which are capable of improving yield while suppressing an increase in time required for rolling.

Solution to Problem

[0007] A control device for a rolling apparatus according to at least one embodiment of the present invention is a control device for controlling a rolling apparatus including a pair of mill rolls for rolling a metal strip, an unwinder for unwinding the strip toward the pair of mill rolls, and a winder for winding the strip rolled by the pair of mill rolls, including: a rotation control unit for controlling rotation of the mill rolls; a velocity acquisition unit configured to acquire velocity of the strip between the unwinder and the mill rolls; and a separation detection unit configured to detect separation of a tail end of the strip from the unwinder. The rotation control unit is configured to stop the rotation of the pair of mill rolls, based on a separation timing which is a timing when the separation of the tail end from the unwinder is detected by the separation detection unit and the velocity of the strip acquired by the velocity acquisition unit.

[0008] Further, a rolling facility according to at least one embodiment of the present invention, includes: a rolling apparatus including a pair of mill rolls for rolling a metal strip, an unwinder for unwinding the strip toward the pair of mill rolls, and a winder for winding the strip rolled by the pair of mill rolls; and the above-described control device for controlling the rolling apparatus.

[0009] A control method for a rolling apparatus according to at least one embodiment of the present invention is a control method for controlling a rolling apparatus including a pair of mill rolls for rolling a metal strip, an unwinder for unwinding the strip toward the pair of mill rolls, and a winder for winding the strip rolled by the pair of mill rolls, including: a rotation control step of controlling rotation of the mill rolls; a velocity acquisition step of acquiring velocity of the strip between the unwinder and the mill rolls; and a separation detection step of detecting separation of a tail end of the strip from the unwinder. The rotation control step includes stopping the rotation of the pair of mill rolls, based on a separation timing which is a timing when the separation of the tail end from the unwinder is detected in the separation detection step and the velocity of the strip acquired in the velocity acquisition step.

Advantageous Effects

[0010] According to at least one embodiment of the present invention, provided are a control device for a rolling apparatus, a rolling facility, and a control method for the rolling apparatus, which are capable of improving yield while suppressing an increase in time required for rolling.

BRIEF DESCRIPTION OF DRAWINGS

[0011] 

FIG. 1 is a schematic configuration view of a rolling facility to which a control device is applied according to an embodiment.

FIG. 2 is a partial cross-sectional view of an unwinder (winder) according to an embodiment.

FIG. 3 is a schematic configuration diagram of the control device according to an embodiment.

FIG. 4 is a flowchart of a control method for a rolling apparatus according to an embodiment.

FIG. 5A is a view for describing a control flow of the rolling apparatus according to an embodiment.

FIG. 5B is a view for describing a control flow of the rolling apparatus according to an embodiment.

FIG. 5C is a view for describing a control flow of the rolling apparatus according to an embodiment.

FIG. 5D is a view for describing a control flow of the rolling apparatus according to an embodiment.

FIG. 6 is a graph showing an example of time variations in a detection value of a sensor, velocity of a strip, and an open/close state of a gripper.

FIG. 7 is a graph showing an example of time variations in a detection value of the sensor, the velocity of the strip, and the open/close state of the gripper.

FIG. 8 is a view for describing the number of windings of the strip in the unwinder.

FIG. 9 is a view for describing the number of windings of the strip in the unwinder.

FIG. 10 is a schematic view of a pressing part according to an embodiment.

FIG. 11 is a schematic view of the pressing part according to an embodiment.

FIG. 12 is a schematic view of the pressing part according to an embodiment.

FIG. 13A is a view for describing an example of a procedure for correcting a shape of a tail end portion of the strip.

FIG. 13B is a view for describing an example of the procedure for correcting the shape of the tail end portion of the strip.

FIG. 13C is a view for describing an example of the procedure for correcting the shape of the tail end portion of the strip.

FIG. 13D is a view for describing an example of the procedure for correcting the shape of the tail end portion of the strip.

DETAILED DESCRIPTION

[0012] Some embodiments of the present invention will be described below with reference to the accompanying drawings. It is intended, however, that unless particularly identified, dimensions, materials, shapes, relative positions and the like of components described or shown in the drawings as the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present invention.

(Configuration of rolling facility)

[0013] FIG. 1 is a schematic configuration view of a rolling facility to which a control device is applied according to an embodiment. As shown in FIG. 1, a rolling facility 100 includes a rolling apparatus 1 for rolling a metal strip S (such as a strip-shaped steel strip), and a control device 50 for controlling the rolling apparatus 1.

[0014] The rolling apparatus 1 includes a rolling mill 10 for rolling the strip S, an unwinder 2 disposed at an entry side of the rolling mill 10 (that is, an upstream side of the rolling mill 10 in a traveling direction of the strip S being rolled), and a winder 3 disposed at an exit side of the rolling mill 10 (that is, a downstream side of the rolling mill 10 in the traveling direction of the strip S being rolled). The rolling apparatus 1 may include, for example, one rolling mill 10 as shown in FIG. 1, or may include not less than two rolling mills 10.

[0015] The rolling mill 10 includes a pair of mill rolls (work rolls) 15, 16 disposed on both surface sides of the strip S with the strip S interposed therebetween. As shown in FIG. 1, the rolling mill 10 may include a pair of intermediate rolls 17, 18 and a pair of backup rolls 19, 20 each disposed opposite to the strip S across the pair of mill rolls 15, 16, respectively. The intermediate rolls 17, 18 and the backup rolls 19, 20 are configured to support the mill rolls 15, 16. Further, the rolling mill 10 includes a rolling-reduction device (such as a hydraulic cylinder; not shown) for performing rolling-reduction on the strip S between the pair of mill rolls 15, 16 by applying a load to the pair of mill rolls 15, 16.

[0016] The mill rolls 15, 16 are connected to a motor 11 via a spindle (not shown), etc., and the mill rolls 15, 16 are rotationally driven by the motor. In rolling of the strip S, a friction force is generated between the strip s and the mill rolls 15, 16 by rotating the mill rolls 15, 16 with the motor 11 while the rolling-reduction device performs rolling-reduction on the strip S. With the friction force, the strip S is sent to the exit side of the mill rolls 15, 16.

[0017] The unwinder 2 is configured to unwind a coil of the strip S toward the rolling mill 10. The unwinder 2 includes a mandrel 4, and is configured to unwind the strip S toward the rolling mill 10 by rotationally driving the mandrel 4 with a motor (not shown). The mandrel 4 of the unwinder 2 is driven by the motor (not shown) to apply an entry-side tension to the strip S, in rolling of the strip S.

[0018] The winder 3 is configured to wind the strip S from the rolling mill 10. The winder 3 includes a mandrel 5, and is configured to wind the strip S by rotationally driving the mandrel 5 with a motor (not shown). When the strip S is rolled while being wound by the mandrel 5 of the winder 3, an exit-side tension is applied to the strip S by the mandrel 5 of the winder 3.

[0019] As shown in FIG. 1, a guide part 12 for guiding the strip S introduced from the mandrel 4 of the unwinder 2 to the rolling mill 10 may be disposed between the rolling mill 10 and the mandrel 4 of the unwinder 2. A guide part 13 for guiding the strip S sent from the rolling mill 10 to the mandrel 5 of the winder 3 may be disposed between the rolling mill 10 and the mandrel 5 of the winder 3 The guide parts 12, 13 may include deflector rolls 6, 7 and/or guide tables 8, 9.

[0020] In some embodiments, the rolling apparatus 1 is a reverse-type rolling apparatus (reverse mill) which is configured to reciprocate and roll the strip S passed between the pair of mill rolls 15, 16. In the reverse-type rolling apparatus 1, rolling is stopped immediately before a tail end St of the strip S unwound from the mandrel 4 of the unwinder 2, and rolling in an odd-number pass (first pass, etc.) is completed in a state where the strip S is subjected to rolling-reduction on the mill rolls 15, 16. And then, the strip S is unwound from the mandrel 5 of the winder 3 toward the rolling mill 10, and rolling in an even-number pass (second pass, etc.) is performed by moving the strip S in a traveling direction reverse to the preceding direction while winding the strip S by the mandrel 4 of the unwinder 2. That is, the role of the unwinder 2 and the role of the winder 3 are interchanged, in accordance with the traveling direction of the strip S.

[0021] FIG. 2 is a partial cross-sectional view of the unwinder 2 (winder 3) according to an embodiment and a view for describing an operation of the unwinder 2 (winder 3). As shown in FIGs. 1 and 2, the unwinder 2 includes a gripper 22 for gripping a tail end portion Sa including the tail end St of the strip S. Further, the winder 3 includes a gripper 23 for gripping a head end portion including a head end of the strip S.

[0022] In the exemplary embodiment shown in FIG. 2, the gripper 22, 23 is disposed to be movable along the radial direction, between an outer peripheral surface of the mandrel 4, 5 and a radially inner side of the mandrel 4, 5. The mandrel 4, 5 is provided with a slot 24 which opens to a surface of the mandrel 4, 5 and can receive the tail end or the head end of the strip S.

[0023] The tail end portion or the head end portion of the strip is gripped by moving the gripper 22, 23 radially outward by an actuator (not shown), etc., and providing the strip S with a force from the gripper 22, 23 toward the mandrel 4, 5. The gripping of the tail end portion or the head end portion of the strip S by the gripper 22, 23 is released by moving the gripper 22, 23 radially inward by an actuator, etc., and releasing a force acting on the strip S from the gripper 22, 23.

[0024] When the strip S is rolled with the rolling apparatus 1, basically, the mill rolls 15, 16, and the mandrels 4 and 5 of the unwinder 2 and the winder 3 are rotated while applying tension to the strip S in a state where the grippers 22, 23 grip the tail end portion and the head end portion of the strip S.

[0025] As shown in FIG. 1, the rolling facility 100 may include a pressing part 30 for correcting a shape of the tail end portion Sa of the strip S. The more detailed configuration of the pressing part 30 will be described later.

[0026] As shown in FIG. 1, the rolling facility 100 may include a velocity sensor 40 for detecting velocity of strip S between the unwinder 2 and the mill rolls 15, 16. The velocity sensor 40 is electrically connected to the control device 50, and a signal indicating the velocity of the strip S detected by the velocity sensor 40 is sent to the control device 50.

[0027] As shown in FIG. 1, the rolling facility 100 may include a sensor 42 for detecting separation of the tail end St of the strip S from the unwinder 2. The sensor 42 may be a sensor capable of detecting presence or absence of the strip S at a position above, below, or lateral to the unwinder 2. The sensor 42 may be a distance meter (laser distance meter, etc.) capable of detecting a distance from the sensor 42 to the strip S. The sensor 42 is electrically connected to the control device 50, and a signal indicating the detection result by the sensor 42 is sent to the control device 50.

[0028] The sensor 42 shown in FIG. 1 is a sensor capable of detecting the presence or absence of the strip S at the position below the unwinder 2. The sensor 42 shown in FIG. 1 is a distance sensor disposed at the position below the unwinder 2 and capable of detecting a distance between the sensor 42 and the strip S in the horizontal direction.

[0029] FIG. 3 is a schematic configuration diagram of the control device 50 according to an embodiment. As shown in FIG. 3, the control device 50 includes a rotation control unit 52, a velocity acquisition unit 54, and a separation detection unit 56. The control device 50 may further include a gripping control unit 58 and/or a pressing control unit 60.

[0030] The rotation control unit 52 is configured to control rotation of the mill rolls 15, 16. More specifically, the rotation control unit 52 is configured to stop the mill rolls 15, 16 based on a separation timing which is a timing when the separation of the tail end St of the strip S from the unwinder 2 is detected by the separation detection unit 56 (described later) and the velocity of the strip S acquired by the velocity acquisition unit 54 (described later). The rotation control unit 52 may be configured to stop the rotation of the mill rolls 15, 16 based on, in addition to the separation timing and the velocity of the strip S which are described above, a length of the strip S from a position of the tail end St at the above-described separation timing to an estimated stop position of the tail end St.

[0031] The velocity acquisition unit 54 is configured to acquire the velocity of the strip S between the unwinder 2 and the mill rolls 15, 16. The velocity acquisition unit 54 may acquire the velocity of the strip S described above, based on the signal indicating the velocity of the strip S, which is received from the above-described velocity sensor 40. Alternatively, the velocity acquisition unit 54 may acquire the velocity of the strip S by acquiring rotation speed of the mill rolls 15, 16 or the motor 11 for driving the mill rolls 15, 16 from a rotation speed sensor, etc., and estimating the velocity of the strip S from the rotation speed by using a backward slip, etc.

[0032] The separation detection unit 56 is configured to detect the separation of the tail end St of the strip S from the unwinder 2. The separation detection unit 56 may be configured to detect the separation of the tail end St from the unwinder 2, based on the signal from the sensor 42 capable of detecting the presence or absence of the strip S at the same position as the guide part 12 (the deflector roll 6, the guide table 8, or the like) or a position between the guide part 12 and the unwinder 2 in the traveling direction of the strip S (a direction from the unwinder 2 toward the winder 3), and the position above, below, or lateral to the unwinder 2.

[0033] The sensor 42 may be configured to detect the presence or absence of the strip S at the position below the unwinder 2 (see the sensor 42 of FIG. 1, a sensor 42A of FIGs. 5A to 5D). In this case, the separation detection unit 56 may be configured to determine, based on the signal from the sensor 42, that the tail end St separates from the unwinder 2, when the presence of the strip S is detected at the position below the unwinder 2.

[0034] The sensor 42 of FIG. 1 and the sensor 42A of FIGs. 5A to 5D are each a distance sensor disposed at the position below the unwinder 2 and capable of detecting a distance between the sensor 42, 42A and the strip S in the horizontal direction.

[0035] Alternatively, the sensor 42 may be configured to detect the presence or absence of the strip S at the position above the unwinder (see a sensor 42B or 42C of FIGs. 5A to 5D). In this case, the separation detection unit 56 may be configured to determine, based on the signal from the sensor 42, that the tail end St separates from the unwinder 2, when the absence of the strip S is detected at the position above the unwinder 2.

[0036] The sensor 42B of FIGs. 5A to 5D is a distance sensor disposed at the position above the unwinder 2 and capable of detecting a distance between the sensor 42B and the strip S in the horizontal direction. The sensor 42C of FIGs. 5A to 5D is a distance sensor disposed at the position above the unwinder 2 and capable of detecting a distance between the sensor 42C and the strip S in the vertical direction.

[0037] FIGs. 5A to 5D are each a view for describing a control flow of the rolling apparatus according to an embodiment. Although FIGs. 5A to 5D show the three sensors 42A, 42B, 42C as the sensor 42, it is possible to detect the separation of the tail end St of the strip S from the unwinder 2 as long as one sensor 42 (for example, any one of the sensors 42A to 42C in FIGs. 5A to 5D) is provided.

[0038] The gripping control unit 58 is configured to control the operation of the gripper 22 (that is, the gripping of the tail end portion or the head end portion of the strip S by the gripper 22, and/or releasing of the gripping). The gripping control unit 58 may be configured to release the gripping of the tail end portion Sa of the strip S by the gripper, based on the number of windings (turns) of the strip S in the unwinder 2. The number of windings of strip S in the unwinder 2 may be calculated from the number of windings or the length of the strip S at the start of the rolling pass and/or an angular position of the gripper 22 around a rotational axis of the mandrel 4, etc.

[0039] The pressing control unit 60 is configured to control the operation of the pressing part 30. The more detailed configuration of the pressing control unit 60 will be described later.

[0040] The control device 50 includes a calculator with a processor (such as CPU), a main storage device (memory device; such as RAM), an auxiliary storage device, an interface, and the like. The control device 50 is configured to receive the signals from the velocity sensor 40 and/or the sensor 42 via the interface. The processor is configured to process the signals thus received. In addition, the processor is configured to process programs loaded into the main storage device. Whereby, the function of each of the functional units (the rotation control unit 52, the velocity acquisition unit 54, the separation detection unit 56, and the like) described above is realized.

[0041] The processing contents in the control device 50 is implemented as programs executed by the processor. The programs may be stored in, for example, the auxiliary storage device. When executed, these programs are loaded into the main storage device. The processor is configured to read out the programs from the main storage device to execute instructions included in the programs.

(Control flow of rolling apparatus)

[0042] Next, a control method for the rolling apparatus 1 according to some embodiments will be described with reference to FIGs. 4 to 9. Hereinafter, a case will be described where the above-described rolling apparatus 1 is controlled by using the above-described control device 50. However, in some embodiments, the control method for the rolling apparatus may be performed by using another device, or part of a procedure described below may be performed manually.

[0043] FIG. 4 is a flowchart of the control method for the rolling apparatus according to an embodiment. FIGs. 5A to 5D are each a view for describing the control flow of the rolling apparatus according to an embodiment, and a view showing a change over time of the position of the strip S in the control of the rolling apparatus.

[0044] As shown in FIG. 4, in the control method according to an embodiment, the gripping control unit 58 releases the gripping of the tail end portion Sa of the strip S by the gripper 22 of the unwinder 2, during rolling of the strip S in the rolling apparatus 1 (S2). Further, the velocity acquisition unit 54 acquires the velocity of the strip S between the unwinder 2 and the mill rolls 15, 16 (S4). Furthermore, the separation detection unit 56 detects the separation of the tail end St of the strip S from the unwinder 2 (S6). Then, the rotation control unit 52 controls and stops the rotation of the mill rolls 15, 16, based on the velocity of the strip S acquired in step S4 and the timing (separation timing) when the separation of the tail end St from the unwinder 2 is detected in the step S6.

[0045] Step S2 includes appropriately operating the actuator for moving the gripper 22 of the unwinder 2 to release the gripping of the tail end portion Sa of the strip S by the gripper 22, if the number of windings of the strip S in the unwinder 2 decreases, during rolling of the strip S in the rolling apparatus 1 (S2). Step S2 typically includes releasing the gripping of the tail end portion Sa by the gripper 22, in a state where the strip S is wound on the mandrel 4 of the unwinder 2 at not less than one round.

[0046] Before the gripping of the tail end portion Sa of the strip S by the gripper 22 is released in step S2, the tail end and the tail end portion of the strip S are unseparated from the mandrel 4 as shown in FIG. 5 A. If the gripping of the tail end portion Sa of the strip S by the gripper 22 is released in step S2, the tail end St and the tail end portion Sa of the strip S separate from the mandrel 4 (unwinder 2) as shown in FIG. 5B. Then, as time passes, positions of the strip S and the tail end St change as shown in FIG. 5C and further as shown in FIG. 5D.

[0047] Step S4 includes acquiring the velocity of the strip S between the unwinder 2 and the mill rolls 15, 16. Step S4 may include acquiring the velocity of the strip S described above, before a point in time when the gripping of the tail end portion Sa by the gripper 22 is released in step S2, or may include acquiring the velocity of the strip S described above, after the point in time. Further, the velocity of the strip S described above may be acquired until the mill rolls 15, 16 are stopped in subsequent step S8. Step S4 may include acquiring the velocity of the strip S described above, continuously or every predetermined period.

[0048] Step S6 includes detecting the separation of the tail end St from the unwinder 2, based on the signal from the sensor 42 capable of detecting the presence or absence of the strip at the position above or below the mandrel 4 of the unwinder 2.

[0049] In an embodiment, whether the tail end St of the strip S separates from the unwinder 2 is determined by using the detection signal of the sensor 42A (see FIGs. 5A to 5D) configured to detect the presence or absence of the strip at the position below the mandrel 4 of the unwinder 2.

[0050] Herein, FIG. 6 is a graph showing an example of time variations in a detection value of the sensor 42A in a period when the rolling apparatus is controlled, the velocity of the strip S between the unwinder 2 and the mill rolls 15, 16 (hereinafter, also simply referred to as the velocity of the strip S), and an open/close state of the gripper 22. The detection value of the sensor 42A when the detection value is not less than D_A indicates a horizontal distance between the sensor 42A and the strip S, which is detected by the sensor 42A, and the detection value less than D_A indicates that the presence of the strip S is not detected.

[0051] In the example shown in FIG. 6, the rolling apparatus 1 rolls the strip S at a steady velocity until time t11. Then, at time 112 later than time 111, the gripping of the tail end portion Sa by the gripper 22 is released (step S2). Until the time t12, the tail end and the tail end portion of the strip S are unseparated from the mandrel 4 as shown in FIG. 5 A. Further, at the time t12, as shown in the graph of FIG. 6, the detection value of the sensor 42A is less than D_A, and the presence of the strip S is not detected.

[0052] For a while after time t14 later than the time t12, the detection value of the sensor 42A is not less than D_A. That is, during this period, the presence of the strip S is detected at the position below the unwinder 2 by the sensor 42A.

[0053] FIG. 5B shows a state at a point in time after the time t12 and before the time t14, where the tail end St separates from the unwinder 2, but has not reached the detection position of the sensor 42A, and the presence of the strip S is not detected by the sensor 42A. FIG. 5C shows a state immediately after the time t14, where the tail end St has reached below the detection position of the sensor 42A, and thus the presence of the strip S is detected by the sensor 42A. Thereafter, the presence of the strip S is no longer detected by the sensor 42A when the tail end St moves above the detection position of the sensor 42A.

[0054] The separation detection unit 56 determines that the tail end St separates from the unwinder 2 at the time 114 when the presence of the strip S is detected at the position below the unwinder 2 by the sensor 42A. In this case, the timing (separation timing) when the tail end St of the strip S separates separates from the unwinder 2 is at the time t14.

[0055] In an embodiment, whether the tail end St of the strip S separates from the unwinder 2 is determined by using the detection signal of the sensor 42B or 42C (see FIGs. 5A to 5D) configured to detect the presence or absence of the strip at the position above the mandrel 4 of the unwinder 2.

[0056] Herein, FIG. 7 is a graph showing an example of time variations in a detection value of the sensor 42B in the period when the rolling apparatus is controlled, the velocity of the strip S between the unwinder 2 and the mill rolls 15, 16, and the open/close state of the gripper 22. The detection value of the sensor 42B when the detection value is not less than D_B indicates a horizontal distance between the sensor 42B and the strip S, which is detected by the sensor 42B, and the detection value less than D_B indicates that the presence of the strip S is not detected.

[0057] In the example shown in FIG. 7, the rolling apparatus 1 rolls the strip S at the steady velocity until time t21. Then, at time t22 later than time t21, the gripping of the tail end portion Sa by the gripper 22 is released (step S2). Until the time t22, the tail end and the tail end portion of the strip S are unseparated from the mandrel 4 as shown in FIG. 5 A. Further, at the time t22, as shown in the graph of FIG. 6, the detection value of the sensor 42A is not less than D_B, and the presence of the strip S is detected.

[0058] In a period after time t24 later than the time t22, the detection value of the sensor 42B is less than D_B. That is, during this period, the presence of the strip S is no longer detected at the position above the unwinder 2 by the sensor 42B.

[0059] FIG. 5C shows a state at a point in time after the time t22 and before the time t24, where the tail end St separates from the unwinder 2, but the strip S exists at the detection position of the sensor 42B, and thus the presence of the strip S is detected by the sensor 42B. FIG. 5D shows a state immediately after the time t24, where the tail end St has reached above the detection position of the sensor 42B, and thus the presence of the strip S is no longer detected by the sensor 42A.

[0060] The separation detection unit 56 determines that the tail end St separates from the unwinder 2 at the time t24 when the presence of the strip S is no longer detected at the position above the unwinder 2 by the sensor 42B. In this case, the timing (separation timing) when the tail end St of the strip S separates from the unwinder 2 is at the time t24.

[0061] Step S8 includes controlling the rotation of the motor 11 to stop the rotation of the mill rolls 15, 16, based on the velocity of the step S acquired in step S4 and the timing (separation timing) when the separation of the tail end St from the unwinder 2 is detected in the step S6.

[0062] By thus stopping the rotation of the mill rolls 15, 16 based on the velocity of the strip S and the separation timing of the tail end St, the strip S can be stopped such that the tail end St is located at a desired position (for example, a position where rolling in a next pass can smoothly be stared; such as a position immediately before the deflector roll 6 or a position of the guide table 8). Therefore, in the reverse-type rolling apparatus 1, even after the tail end St separates from the unwinder 2, rolling can continue until the mill rolls 15, 16 stop, as well as rolling in the next pass can smoothly be started. Therefore, yield can be improved while suppressing an increase in time required for rolling.

[0063] Step S8 may include stopping the rotation of the mill rolls 15, 16 based on, in addition to the velocity of the strip S and the separation timing of the tail end St, the length of the strip S from the position of the tail end St at the separation timing to the estimated stop position of the tail end St. A movement length of the strip S (that is, a movement length of the tail end St) can be expressed as a time integral of the velocity of the strip S. Therefore, the strip S can easily be stopped such that the tail end St is located at a desired estimated stop position, by controlling the rotation and the stop of the mill rolls 15, 16 (motor 11) with the rotation control unit so that the time integral of the velocity of the strip S acquired by the velocity acquisition unit 54 is the length of the strip S described above. Thus, it becomes easier to smoothly start rolling in the next pass.

[0064] As the length of the strip S from the position of the tail end St at the separation timing of the tail end St from the unwinder 2 to the estimated stop position of the tail end St, a length may be used which is geometrically obtained based on the sensors 42 (sensors 42A to 42C, etc.) for detecting the separation of the tail end St, the estimated stop position of the tail end St, and the like.

[0065] Step S8 may include increasing or decreasing the velocity of the strip S during a period between the separation timing of the tail end St from the unwinder 2 and the stopping of the mill rolls 15, 16, for example, as shown in FIG. 6 or 7. In the examples shown in FIGs. 6 and 7, the velocity of the strip S is increased from time t15 or t25 after the separation timing (time t14 or t24) to time t16 or t26, and the velocity of the strip S is decreased from the time t16 or t26 to time t17 or t27 (when mill rolls 15, 16 stop). The time required for rolling the strip S can be reduced by thus increasing the velocity of the strip S as much as possible until immediately before the strip S stops, and the tail end St is stably and easily located at the desired estimated stop position by thus decreasing the velocity of the strip S immediately before the strip S stops.

[0066] Herein, FIGs. 8 and 9 are each a view for describing the number of windings of the strip S in the unwinder 2. The number of windings of the strip S is counted based on an angular position of the gripper 22 around the rotational axis of the mandrel 4 of the unwinder 2. In FIG. 8, the angular position of the gripper 22 is the same as an angular position T where the strip S wound on the unwinder 2 is unwound toward the mill rolls 15, 16 (a position where the shape of the strip S changes from an arc shape to a linear shape). That is, FIG. 8 shows a state where the strip S is wound on the mandrel 4 of the unwinder 2 at one round. In FIG. 9, the angular position of the gripper 22 is a position 180-degree rotated from the above-described angular position T. That is, FIG. 9 shows a state where the strip S is wound on the mandrel 4 of the unwinder 2 at 1.5 rounds.

[0067] In the above-described method, step S2 may include releasing the gripping of the tail end portion Sa by the gripper 22, immediately before the tail end St of the strip S separates from the unwinder 2.

[0068] Since tension acts on the strip S during the period when the gripper 22 of the unwinder 2 grips the tail end portion Sa of the strip S, a portion of the strip S rolled during this period can be a product. In this regard, by releasing the gripping of the tail end portion Sa by the gripper 22 immediately before the tail end St separates from the unwinder 2 as described above, the tension acting on the strip S can be maintained until immediately before the tail end St separates from the unwinder 2. Thus, it is possible to improve the yield more effectively.

[0069] More specifically, step S2 may include releasing the gripping of the tail end portion Sa by the gripper 22 while not greater than 2 windings or not greater than 1.7 windings of the strip S is wound on the unwinder 2.

[0070] By thus releasing the gripping of the tail end portion Sa by the gripper 22 while not greater than 2 windings or not greater than 1.7 than 1.7 windings of the strip is wound on the unwinder 2, the tension acting on the strip S can be maintained until immediately before the tail end St separates from the unwinder 2.

[0071] Further, step S2 may include releasing the gripping of the tail end portion Sa by the gripper 22 while more than 1 winding or 1.5 windings of the strip S is wound on the unwinder 2.

[0072] The tail end St of the strip S can separate from the unwinder 2 when not greater than one winding of the strip S is wound on the unwinder 2. In this regard, as described above, since the gripping of the tail end portion by the gripper is released while more than 1 winding or 1.5 windings of the strip S is wound on the unwinder 2, that is, before the tail end of the strip S can separate from the unwinder, the tail end of the strip can smoothly be separated from the unwinder.

[0073] In some embodiments, the gripping of the tail end portion Sa by the gripper 22 may be released while not less than 1 winding and not greater than 2 windings of the strip S is wound on the unwinder 2. In some embodiments, the gripping of the tail end portion Sa by the gripper 22 may be released while not less than 1.5 windings and not greater than 1.7 windings of the strip S is wound on the unwinder 2.

[0074] In the above-described method, step S2 may include decreasing rotation speed of the mill rolls 15, 16 in a period including a timing when the gripping of the tail end portion Sa by the gripper 22 is released. For example, in the example shown in FIG. 6 or 7, the rotation speed of the mill rolls 15, 16 is decreased in the period including the time t12 or t22 (a period from t11 to t13 or a period from t21 to t23) when the gripping of the tail end portion Sa by the gripper 22 is released.

[0075] By thus decreasing the rotation speed of the mill rolls 15, 16 when the gripping of the tail end portion Sa by the gripper 22 is released, the rotation speed of the mill rolls 15, 16 is maintained relatively high until immediately before the timing when the gripping of the tail end portion Sa is released. Therefore, it is possible to effectively suppress the increase in time required for rolling.

(As to shape correction of tail end portion by pressing part)

[0076] Next, a more specific configuration, of the pressing part 30 and the pressing control unit 60, for correcting the shape of the tail end portion Sa of the strip S will be described.

[0077] As shown in FIG. 1, the pressing part 30 is disposed so as to at least partially located, in the traveling direction of travel of the strip S, between the mill rolls 15, 16 and a rotational axis O of the deflector roll 6 disposed between the unwinder 2 and the mill rolls 15, 16. The pressing part 30 is configured to provide the strip S with a pressing force along a strip thickness direction of the strip S.

[0078] The pressing control unit 60 (see FIG. 3) is configured to control the operation of the pressing part 30. The pressing control unit 60 may be configured to operate the pressing part 30 such that the pressing force is applied to the strip S by the pressing part 30, after the tail end St of the strip S separates from the unwinder 2. The pressing control unit 60 may be configured to apply the pressing force to the strip S by the pressing part 30 in a state where the mill rolls 15, 16 are rotated (that is, in a state where the strip S is conveyed).

[0079] The tail end portion Sa of the strip S, which separates from the unwinder 2, usually has a shape curved relatively greatly (strong winding habit). According to the above configuration, since, after the tail end St separates from the unwinder 2, the mill rolls 15, 16 are rotated in the state where the pressing force is applied to the strip S by the pressing part 30 disposed in the vicinity of the deflector roll 6, the degree of curvature of the tail end portion Sa can be reduced. By thus correcting the shape of the tail end portion Sa of the strip S, rolling in the next pass can be started more smoothly. For example, it becomes easier to pass the head end portion of the strip S in the next pass (the tail end portion Sa in the previous pass) through the guide part 12, or to grip the head end portion of the strip S in the next pass with the gripper of the winder (the unwinder 2 in the previous pass). Therefore, it is possible to effectively suppress the increase in time required for rolling.

[0080] FIGs. 10 to 12 are each a schematic view of the pressing part 30 according to an embodiment.

[0081] The pressing part 30 shown in FIG. 10 includes: a pinch roll 32 partially disposed between the mill rolls 15, 16 and the deflector roll 6 and configured to pinch the strip S together with the deflector roll 6; and a push roll 34 disposed between the mill rolls 15, 16 and the deflector roll 6 in the traveling direction of the strip S, and opposite to the pinch roll 32 across the strip S. The push roll 34 is configured to be able to provide the strip S with a pressing force along upward. As shown in FIG. 10, a center of the pinch roll 32 in the traveling direction of the strip S (hereinafter, also simply referred to as the traveling direction) is located off the rotational axis of the deflector roll 6 to a side of the mill rolls 15, 16 by a distance L1 in the traveling direction. Further, a center of the push roll 34 in the traveling direction is located off the center of the pinch roll 32 described above to the side of the mill rolls 15, 16 by a distance L2 in the traveling direction.

[0082] In the present embodiment, the shape of the tail end portion Sa of the strip S can be corrected by pinching the strip S with the deflector roll 6 and the pinch roll 32 and rotating the mill rolls 15, 16 in a state where the pressing force from the push roll 34 acts on the strip S.

[0083] The pressing part 30 shown in FIG. 11 includes a pinch roll 33 partially disposed between the mill rolls 15, 16 and the deflector roll 6 and configured to pinch the strip S together with the deflector roll 6. The pinch roll 33 is configured to be able to provide the strip S with a pressing force along a direction from the center of pinch roll 33 to the center of deflector roll 6. As shown in FIG. 11, a center of the pinch roll 33 in the traveling direction of the strip S is located off the rotational axis of the deflector roll 6 to the side of the mill rolls 15, 16 by a distance L3 in the traveling direction.

[0084] In the present embodiment, the mill rolls 15, 16 are rotated while rotating the deflector roll 6 and the pinch roll 33, in the state where the strip S is pinched with the deflector roll 6 and the pinch roll 33 and the pressing force from the pinch roll 33 acts on the strip S. The shape of the tail end portion Sa of the strip S can be corrected by thus applying tension to the strip S.

[0085] The pressing part 30 shown in FIG. 12 includes a forming part 36 disposed between the mill rolls 15, 16 and the deflector roll 6, and a receiving part 38 disposed opposite to the forming part 36 across the strip S. The forming part 36 is disposed to be vertically movable. The receiving part 38 has a contact surface 38a that can contact the surface of the strip S in a state where the strip S is interposed between the contact surface 38a and the forming part 36. Further, the receiving part 38 is configured to change its posture in response to the vertical movement of the forming part 36. Furthermore, in the embodiment shown in FIG. 12, a pinch roll 35, which is configured to pinch the strip S together with the deflector roll 6, is disposed above the deflector roll 6.

[0086] In the exemplary embodiment shown in FIG. 12, a cross-section of the forming part 36 has a circular shape, but the shape of the forming part 36 is not limited to this. For example, the cross-sectional shape of the forming part 36 may be rectangular, polygonal, home base, oval, or the like.

[0087] In the present embodiment, the mill rolls 15, 16 are rotated in a state where the strip S is pinched with the deflector roll 6 and the pinch roll 33, as well as the strip S is pinched with the forming part 36 and the receiving part 38, and the pressing force from the forming part 36 is applied to the strip S by moving the forming part 36 downward. Whereby, the shape of the tail end portion Sa of the strip S can be corrected.

[0088] In some embodiments, the rotation control unit 52 may be configured to repeat the rotation and stop of the mill rolls 15, 16 in the state where the pressing force is applied to the strip S by the pressing part 30.

[0089] According to the above-described embodiment, since the rotation and stop of the pair of mill rolls 15, 16 are repeated in the state where the pressing force is applied to the strip S by the pressing part 30, the shape of the tail end portion can be corrected by shifting the position of the strip S little by little. Whereby, the shape of the tail end portion can be adjusted more finely.

[0090] FIGs. 13A to 13D are each a view for describing an example of the procedure for correcting the shape of the tail end portion Sa while repeating the rotation and stop of the mill rolls 15, 16 (that is, while inching the strip S). In the present example, the pressing part 30 shown in FIG. 12 is used to correct the shape of the tail end portion Sa of the strip S.

[0091] First, as shown in FIG. 13A, in a position of the forming part 36 in the traveling direction, the position of the forming part 36 is adjusted such that the vertical position (height) of the strip S is at the same level as the strip S between the mill rolls 15, 16. In this state, the mill rolls 15, 16 are slightly rotated and stopped while the strip S is pinched with the forming part 36 and the receiving part 38, and the pressing force from the forming part 36 is applied to the strip S.

[0092] Next, as shown in FIG. 13B, the position of the forming part 36 is adjusted to a position lower than the position in the case of FIG. 13A. In this state, the mill rolls 15, 16 are slightly rotated and stopped while the strip S is pinched with the forming part 36 and the receiving part 38, and the pressing force from the forming part 36 is applied to the strip S.

[0093] Further, as shown in FIG. 13C, the position of the forming part 36 is adjusted to a position lower than the position in the case of FIG. 13B. In this state, the mill rolls 15, 16 are slightly rotated and stopped while the strip S is pinched with the forming part 36 and the receiving part 38, and the pressing force from the forming part 36 is applied to the strip S. By thus increasing the amount of push-in (push-down) of the forming part 36, the portion, of the strip S, in the vicinity of the tail end St having a stronger winding habit can effectively be corrected in shape.

[0094] If the tail end St of the strip S exceeds the deflector roll 6 and the forming part 36, the forming part 36 may be moved upward and separated from the receiving part 38 to release the application of the pressing force to the strip S by the forming part 36, as shown in FIG. 14D.

[0095] By thus appropriately moving the forming part 36 in accordance with the change in shape of the tail end portion Sa, and repeating the procedure for slightly rotating and stopping the mill rolls 15, 16 in the state where the pressing force from the forming part 36 is applied to the strip S, the shape of the tail end portion Sa can effectively be corrected while shifting the position of the strip S little by little.

[0096] Hereinafter, the overview of the control device for the rolling apparatus, the rolling facility, and the control method for the rolling apparatus according to some embodiments will be described.

(1) A control device (50) for a rolling apparatus (1) according to at least one embodiment of the present invention is a control device for controlling a rolling apparatus including a pair of mill rolls (15, 16) for rolling a metal strip (S), an unwinder (2) for unwinding the strip toward the pair of mill rolls, and a winder (3) for winding the strip rolled by the pair of mill rolls, including: a rotation control unit (52) for controlling rotation of the mill rolls; a velocity acquisition unit (54) configured to acquire velocity of the strip between the unwinder and the mill rolls; and a separation detection unit (56) configured to detect separation of a tail end (St) of the strip from the unwinder. The rotation control unit is configured to stop the rotation of the pair of mill rolls, based on a separation timing which is a timing when the separation of the tail end from the unwinder is detected by the separation detection unit and the velocity of the strip acquired by the velocity acquisition unit.
According to the above configuration (1), since the rotation of the rolling mill is controlled and stopped based on the timing when the separation of the tail end of the strip from the unwinder is detected and the velocity of the strip between the unwinder and the mill rolls, the strip can be stopped at an appropriate position (for example, a position where rolling in the next pass can smoothly be started). Therefore, in the reverse-type rolling apparatus, even after the tail end separates from the unwinder, rolling can continue until the rolling mill stops, as well as rolling in the next pass can smoothly be started. Therefore, the yield can be improved while suppressing the increase in time required for rolling.

(2) In some embodiments, in the above configuration (1), the separation detection unit is configured to detect the separation of the tail end from the unwinder, based on a signal from a sensor (42) capable of detecting presence or absence of the strip at a position above or below the unwinder.
According to the above configuration (2), the separation of the tail end from the unwinder can appropriately be detected by the sensor capable of detecting the presence or absence of the strip at the position above or below the unwinder. Therefore, as described in (1), the yield can be improved while suppressing the increase in time required for rolling.

(3) In some embodiments, in the above configuration (2), the rolling apparatus includes a guide part (12) for guiding the strip between the unwinder and the pair of mill rolls, and the separation detection unit is configured to detect the separation of the tail end from the unwinder, based on a signal from a sensor (42) capable of detecting the presence or absence of the strip at the same position as the guide part or a position between the guide part and the unwinder in a traveling direction of the strip, and the position above or below the unwinder.
A passage for the strip in the guide part usually has a narrow gap in the strip thickness direction, making it relatively difficult to pass the head end of the strip through. In this regard, according to the above configuration (3), since the separation of the tail end from the unwinder is detected by using the sensor capable of detecting the presence or absence of the strip at the same position as the guide part or the position between the guide part and the unwinder in the traveling direction of the strip, the tail end (that is, the head end in the next pass) of the strip is easily stopped at the same position as the guide part or the position between the guide part and the unwinder. Thus, it becomes easier to smoothly start rolling in the next pass.

(4) In some embodiments, in the above configuration (2) or (3), the separation detection unit is configured to determine, based on the signal from the sensor, that the tail end separates from the unwinder, when the presence of the strip is detected at the position below the unwinder.
According to the above configuration (4), since the separation of the tail end from the unwinder is detected based on the presence of the strip at the position below the unwinder, it is possible to promptly determine that the strip separates from the unwinder.

(5) In some embodiments, in the above configuration (2) or (3), the separation detection unit is configured to determine, based on the signal from the sensor, that the tail end separates from the unwinder, when the absence of the strip is detected at the position above the unwinder.
According to the above configuration (5), since the separation of the tail end from the unwinder is detected based on the absence of the strip at the position above the unwinder, it is possible to relatively promptly determine that the strip separates from the unwinder.

(6) In some embodiments, in any of the above configurations (1) to (5), the rotation control unit is configured to stop the rotation of the pair of mill rolls based on, in addition to the separation timing and the velocity of the strip, a length of the strip from a position of the tail end at the separation timing to an estimated stop position of the tail end.
According to the above configuration (6), since the rotation of the mill rolls is stopped based on, in addition to the separation timing of the tail end from the unwinder and the velocity of the strip, the length of the strip from the position of the tail end at the separation timing to the estimated stop position (predetermined position) of the tail end, the strip can be stopped such that the tail end is located at the desired position (estimated stop position). Thus, it becomes easier to smoothly start rolling in the next pass.

(7) In some embodiments, in any of the above configurations (1) to (6), the control device includes: a gripping control unit (58) disposed in the unwinder and configured to control a gripper (22) for gripping a tail end portion (Sa) including the tail end of the strip. The gripping control unit is configured to release the gripping of the tail end portion by the gripper, immediately before the tail end separates from the unwinder.
Since tension acts on the strip during the period when the gripper of the unwinder grips the tail end portion of the strip, a portion of the strip rolled during this period can be a product. In this regard, according to the above configuration (7), since the gripping of the tail end portion by the gripper is released immediately before the tail end separates from the unwinder, the tension acting on the strip can be maintained until immediately before the tail end separates from the unwinder. Thus, it is possible to improve the yield more effectively.

(8) In some embodiments, in the above configuration (7), the gripping control unit is configured to release the gripping of the tail end portion by the gripper, while more than one winding of the strip is wound on the unwinder.
The tail end of the strip can separate from the unwinder when not greater than one winding of the strip is wound on the unwinder. In this regard, according to the above configuration (8), since the gripping of the tail end portion by the gripper is released before the tail end of the strip can separate from the unwinder and immediately before the tail end separates from the unwinder, the tail end of the strip can smoothly be separated from the unwinder, as well as the tension acting on the strip is maintained until immediately before the tail end separates from the unwinder, making it possible to improve the yield.

(9) In some embodiments, in the above configuration (7) or (8), the gripping control unit is configured to release the gripping of the tail end portion by the gripper, while not greater than two windings of the strip is wound on the unwinder.
According to the above configuration (9), since the gripping of the tail end portion by the gripper is released while not greater than two windings of the strip is wound on the unwinder, the tension acting on the strip can be maintained until immediately before the tail end separates from the unwinder. Thus, it is possible to improve the yield more effectively.

(10) In some embodiments, in any of the above configurations (7) to (9), the rotation control unit is configured to decrease rotation speed of the pair of mill rolls in a period including a timing when the gripping of the tail end portion is released by the gripping control unit.
According to the above configuration (10), since the rotation speed of the mill rolls is decreased when the gripping of the tail end portion is released, the rotation speed of the mill rolls is maintained relatively high until immediately before the gripping of the tail end portion is released. Therefore, it is possible to effectively suppress the increase in time required for rolling.

(11) In some embodiments, in any of the above configurations (1) to (10), the rolling apparatus includes a deflector roll (6) disposed between the unwinder and the pair of mill rolls, and a pressing part (30) at least partially located between the deflector roll and the pair of mill rolls in a traveling direction of the strip and configured to provide the strip with a pressing force along a strip thickness direction of the strip, the control device includes: a pressing control unit (60) configured to operate the pressing part such that the pressing force is applied to the strip by the pressing part, after the tail end separates from the unwinder, and the rotation control unit is configured to rotate the pair of mill rolls in a state where the pressing force is applied to the strip by the pressing part.
The tail end portion of the strip, which separates from the unwinder, usually has a shape curved relatively greatly (strong winding habit). According to the above configuration (11), since, after the tail end separates from the unwinder, the mill rolls are rotated in the state where the pressing force is applied to the strip by the pressing part disposed in the vicinity of the deflector roll, the degree of curvature of the tail end portion can be reduced. By thus correcting the shape of the tail end portion of the strip, rolling in the next pass can be started more smoothly, for example, it becomes easier to grip the head end portion of the strip in the next pass (the tail end portion in the previous pass) with the gripper of the winder (the unwinder in the previous pass). Therefore, it is possible to effectively suppress the increase in time required for rolling.

(12) In some embodiments, in the above configuration (11), the rotation control unit is configured to repeat the rotation and stop of the pair of mill rolls in the state where the pressing force is applied to the strip by the pressing part.
According to the above configuration (12), since the rotation and stop of the pair of mill rolls are repeated in the state where the pressing force is applied to the strip by the pressing part, the shape of the tail end portion can be corrected by shifting the position of the strip little by little. Whereby, the shape of the tail end portion can be adjusted more finely.

(13) A rolling facility (100) according to at least one embodiment of the present invention, includes: a rolling apparatus (1) including a pair of mill rolls (15, 16) for rolling a metal strip (S), an unwinder (2) for unwinding the strip toward the pair of mill rolls, and a winder (3) for winding the strip rolled by the pair of mill rolls; and the control device (50) according to any one of the above (1) to (12) for controlling the rolling apparatus.
According to the above configuration (13), since the rotation of the rolling mill is controlled and stopped based on the timing when the separation of the tail end of the strip from the unwinder is detected and the velocity of the strip between the unwinder and the mill rolls, the strip can be stopped at an appropriate position (for example, a position where rolling in the next pass can smoothly be started). Therefore, in the reverse-type rolling apparatus, even after the tail end separates from the unwinder, rolling can continue until the rolling mill stops, as well as rolling in the next pass can smoothly be started. Therefore, the yield can be improved while suppressing the increase in time required for rolling.

(14) A control method for a rolling apparatus according to at least one embodiment of the present invention is a control method for controlling a rolling apparatus (1) including a pair of mill rolls (15, 16) for rolling a metal strip (S), an unwinder (2) for unwinding the strip toward the pair of mill rolls, and a winder (3) for winding the strip rolled by the pair of mill rolls, including: a rotation control step (S8) of controlling rotation of the mill rolls; a velocity acquisition step (S4) of acquiring velocity of the strip between the unwinder and the mill rolls; and a separation detection step (S6) of detecting separation of a tail end of the strip from the unwinder. The rotation control step includes stopping the rotation of the pair of mill rolls, based on a separation timing which is a timing when the separation of the tail end from the unwinder is detected in the separation detection step and the velocity of the strip acquired in the velocity acquisition step.

[0097] According to the above method (14), since the rotation of the rolling mill is controlled and stopped based on the timing when the separation of the tail end of the strip from the unwinder is detected and the velocity of the strip between the unwinder and the mill rolls, the strip can be stopped at an appropriate position (for example, a position where rolling in the next pass can smoothly be started). Therefore, in the reverse-type rolling apparatus, even after the tail end separates from the unwinder, rolling can continue until the rolling mill stops, as well as rolling in the next pass can smoothly be started. Therefore, the yield can be improved while suppressing the increase in time required for rolling.

[0098] Embodiments of the present invention were described in detail above, but the present invention is not limited thereto, and also includes an embodiment obtained by modifying the above-described embodiments and an embodiment obtained by combining these embodiments as appropriate.

[0099] Further, in the present specification, an expression of relative or absolute arrangement such as "in a direction", "along a direction", "parallel", "orthogonal", "centered", "concentric" and "coaxial" shall not be construed as indicating only the arrangement in a strict literal sense, but also includes a state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance whereby it is possible to achieve the same function.

[0100] For instance, an expression of an equal state such as "same" "equal" and "uniform" shall not be construed as indicating only the state in which the feature is strictly equal, but also includes a state in which there is a tolerance or a difference that can still achieve the same function.

[0101] Further, an expression of a shape such as a rectangular shape or a cylindrical shape shall not be construed as only the geometrically strict shape, but also includes a shape with unevenness or chamfered corners within the range in which the same effect can be achieved.

[0102] As used herein, the expressions "comprising", "including" or "having" one constitutional element is not an exclusive expression that excludes the presence of other constitutional elements.

Reference Signs List

[0103] 

1

Rolling apparatus

2

Unwinder

3

Winder

4, 5

Mandrel

6, 7

Deflector roll

8, 9

Guide table

10

Rolling mill

11

Motor

12, 13

Guide part

15, 16

Mill roll

17, 18

Intermediate roll

19, 20

Backup roll

22, 23

Gripper

24

Slot

30

Pressing part

32

Pinch roll

33

Pinch roll

34

Push roll

35

Pinch roll

36

Forming part

38

Receiving part

38a

Contact surface

40

Velocity sensor

42, 42A to 42C

Sensor

50

Control device

52

Rotation control unit

54

Velocity acquisition unit

56

Separation detection unit

58

Gripping control unit

60

Pressing control unit

100

Rolling facility

S

Strip

Sa

Tail end portion

St

Tail end

Claims

1. A control device for controlling a rolling apparatus including a pair of mill rolls for rolling a metal strip, an unwinder for unwinding the strip toward the pair of mill rolls, and a winder for winding the strip rolled by the pair of mill rolls, comprising:

a rotation control unit for controlling rotation of the mill rolls;

a velocity acquisition unit configured to acquire velocity of the strip between the unwinder and the mill rolls; and

a separation detection unit configured to detect separation of a tail end of the strip from the unwinder,

wherein the rotation control unit is configured to stop the rotation of the pair of mill rolls, based on a separation timing which is a timing when the separation of the tail end from the unwinder is detected by the separation detection unit and the velocity of the strip acquired by the velocity acquisition unit.

2. The control device for the rolling apparatus according to claim 1,
wherein the separation detection unit is configured to detect the separation of the tail end from the unwinder, based on a signal from a sensor capable of detecting presence or absence of the strip at a position above or below the unwinder.

3. The control device for the rolling apparatus according to claim 2,

wherein the rolling apparatus includes a guide part for guiding the strip between the unwinder and the pair of mill rolls, and

wherein the separation detection unit is configured to detect the separation of the tail end from the unwinder, based on a signal from a sensor capable of detecting the presence or absence of the strip at the same position as the guide part or a position between the guide part and the unwinder in a traveling direction of the strip, and the position above or below the unwinder.

4. The control device for the rolling apparatus according to claim 2 or 3,
wherein the separation detection unit is configured to determine, based on the signal from the sensor, that the tail end separates from the unwinder, when the presence of the strip is detected at the position below the unwinder.

5. The control device for the rolling apparatus according to claim 2 or 3,
wherein the separation detection unit is configured to determine, based on the signal from the sensor, that the tail end separates from the unwinder, when the absence of the strip is detected at the position above the unwinder.

6. The control device for the rolling apparatus according to any one of claims 1 to 5,
wherein the rotation control unit is configured to stop the rotation of the pair of mill rolls based on, in addition to the separation timing and the velocity of the strip, a length of the strip from a position of the tail end at the separation timing to an estimated stop position of the tail end.

7. The control device for the rolling apparatus according to any one of claims 1 to 6, comprising:

a gripping control unit disposed in the unwinder and configured to control a gripper for gripping a tail end portion including the tail end of the strip,

wherein the gripping control unit is configured to release the gripping of the tail end portion by the gripper, immediately before the tail end separates from the unwinder.

8. The control device for the rolling apparatus according to claim 7,
wherein the gripping control unit is configured to release the gripping of the tail end portion by the gripper, while more than one winding of the strip is wound on the unwinder.

9. The control device for the rolling apparatus according to claim 7 or 8,
wherein the gripping control unit is configured to release the gripping of the tail end portion by the gripper, while not greater than two windings of the strip is wound on the unwinder.

10. The control device for the rolling apparatus according to any one of claims 7 to 9,
wherein the rotation control unit is configured to decrease rotation speed of the pair of mill rolls in a period including a timing when the gripping of the tail end portion is released by the gripping control unit.

11. The control device for the rolling apparatus according to any one of claims 1 to 10,

wherein the rolling apparatus includes a deflector roll disposed between the unwinder and the pair of mill rolls, and a pressing part at least partially located between the deflector roll and the pair of mill rolls in a traveling direction of the strip and configured to provide the strip with a pressing force along a strip thickness direction of the strip,

wherein the control device comprises a pressing control unit configured to operate the pressing part such that the pressing force is applied to the strip by the pressing part, after the tail end separates from the unwinder, and

wherein the rotation control unit is configured to rotate the pair of mill rolls in a state where the pressing force is applied to the strip by the pressing part.

12. The control device for the rolling apparatus according to claim 11,
wherein the rotation control unit is configured to repeat the rotation and stop of the pair of mill rolls in the state where the pressing force is applied to the strip by the pressing part.

13. A rolling facility comprising:

a rolling apparatus including a pair of mill rolls for rolling a metal strip, an unwinder for unwinding the strip toward the pair of mill rolls, and a winder for winding the strip rolled by the pair of mill rolls; and

the control device according to any one of claims 1 to 12 for controlling the rolling apparatus.

14. A control method for controlling a rolling apparatus including a pair of mill rolls for rolling a metal strip, an unwinder for unwinding the strip toward the pair of mill rolls, and a winder for winding the strip rolled by the pair of mill rolls, comprising:

a rotation control step of controlling rotation of the mill rolls;

a velocity acquisition step of acquiring velocity of the strip between the unwinder and the mill rolls; and

a separation detection step of detecting separation of a tail end of the strip from the unwinder,

wherein the rotation control step includes stopping the rotation of the pair of mill rolls, based on a separation timing which is a timing when the separation of the tail end from the unwinder is detected in the separation detection step and the velocity of the strip acquired in the velocity acquisition step.

Drawing