JPH02178179A - Tension controller for strip - Google Patents

Abstract

PURPOSE:To make tension controllable in a highly accurate manner by detecting the extent of moment being imposed on a rotation support part of a directional control roll, and compensating the detected value according to the width, thickness and type of a strip. CONSTITUTION:Force F detected by a load cell 16 of a directional control roll (detection roll) 10 for a strip 8 is inputted into a computing element 32 after being converted by an analog-to-digital converter 30. At this computing element 32, operation is carried out as in illustration according to a known parameter and thickness (t), breadth (b) and density (p) of the strip 8 being set from the outside and thereby outlet side tension T2 is operated. Then, the output is inputted into a comparator 34, and compared with standard tension TS or the desired value found by multiplying unit tension tS by those of breadth (b) and thickness (t). The deviation is inputted into a motor control circuit 36, and thereby each rotation of drive motors 38, 40 for bridle rolls 18, 20 is controlled so as to cause the outlet side tension T2 to become the standard tension TS.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a strip tension control device, particularly in various processing lines such as continuous annealing furnaces and rolling lines.
The present invention relates to a strip tension control device that is capable of highly accurately detecting the tension of a strip such as a steel strip as it passes over a direction change roll and controlling the tension to a target value.

[Conventional technology]

High precision control of strip tension is required in various processing lines that process strips such as steel strips, especially in processing lines such as continuous annealing furnaces, and rolling lines such as cold rolling mills and temper rolling mills. Special Public Service 59-29
321 and Japanese Patent Publication No. 59-14528 disclose tension control methods and devices for this purpose. In addition, various methods for detecting tension have been proposed. For example, as a method for controlling the tension of a tension pry roll based on the torque characteristics of the motor, the field current of a DC motor is fixed, and the armature current of the motor is used to detect the tension. A method for controlling in proportion to a standard is disclosed in Japanese Patent Publication No. 62-8212, and there is also a method disclosed in Japanese Patent Publication No. 53-22870. Generally, in a continuous annealing line, etc., as shown in Figure 6,
Groups of priddle rolls are arranged on the entrance and exit sides of the annealing furnace, respectively, and the roll 10 closest to the annealing furnace (in the case of the entrance side of the annealing furnace as shown in Fig. 6, the rearmost roll) among the priddle roll groups is detected. As a roll, the roll 10 has a fulcrum 12
A bearing arm 12 is provided to support the roll 10 with A as the rotation center, and a strip 8 is provided on the bearing arm 12.
In many cases, a moment based on the tension is detected by a load cell 16 disposed on the support frame 14, and the tension is controlled based on this signal. That is, the tension when the strip 8 passes over the priddle roll 10 is converted into a rotation force about the rotation fulcrum 12A of the bearing arm 12 of the roll 10, and the tension is generated between the bearing arm 12 and the support frame 14. When this rotational force acts on the interposed load cell I6, a detection output regarding the tension of the strip 8 is obtained from the load cell 16.

However, in the method as shown in FIG. Errors in turning force due to bend loss when bending along,
Since there is a detection error of the load cell 16 due to a change in the weight of the strip 8, the tension cannot be detected with high precision, and therefore the tension cannot be controlled with high precision. The present invention was made to solve the above-mentioned conventional problems, and regardless of changes in the thickness or weight of the strip,
It is an object of the present invention to provide a strip tension control device that is capable of detecting tension with high precision and therefore capable of performing tension control with high precision.

[Means to achieve the task]

The present invention provides a strip tension control device that detects the tension when the strip passes over a direction change roll and controls it to a drift value, comprising: means for detecting a moment applied to a rotating support portion of the direction change roll; The detected value is corrected according to the width, thickness, and type of the strip to eliminate errors in the winding angle around the direction change roll and rotational force due to bend loss.
The above object has been achieved by providing a correction means for eliminating the influence of errors due to the weight of the strip.

[Operation 1] The operation of the present invention will be explained in detail below, taking as an example a case where a load cell is used to detect a moment acting on a rotational support portion of a direction change roll. Assuming that the rotation center (roll center) P of the direction change roll (detection roll) 10, the rotation fulcrum 12A of the bearing arm 12, and the load cell 16 are in the position relationship shown in FIG. 2, the moment applied to the load cell 16 is The following relationship holds true between FXJ3 and the exit tension T2 of the strip 8. T 2 = T H + loss = T + +v (1+o/2+I +t)xcos
(θ2-θ3), + W - B L + M L...
(1) Here, T1 is the entry tension, W is the weight 1k per unit length of the strip 8 (W = b xt 1o is the distance between the detection roll 10 and the next roll 22 (for example, the hearth roll of an annealing furnace), as shown in FIG. The distance between the roll 10 and the immediately preceding priddle roll 20, θ2 is the angle between the composite tension Tt of the input tension T1 and the output tension T2 and the vertical line, and θ3 is the composite tension Tt, as shown in FIG. is the angle made with respect to the perpendicular to the line connecting the rotation fulcrum 12A and the roll center P, W is the weight of the detection roll 10 including the bearing, BL is the bend loss due to the spring back of the strip 8, ML is the roll rotation axis This is a loss due to friction. Here, the bend loss BL is calculated from the following formula based on experience: % where E is the Young's modulus of the strip material and D is the roll diameter. Further, the loss ML due to the friction of the roll rotation shaft is expressed by the following equation, as shown in FIG. M L = Z・μ・(R1/R2) (3) Here, 2 is the composite load of the composite tension Tt and the load Tw due to the sum of the plate weight and roll weight W, and μ is the load of the roll bearing. Coefficient of friction, R1 is the radius of the rotating shaft, R2 is the roll radius (=D/2). Therefore, the force F applied to the load cell 16 is expressed by the following equation. F = T o = Tt CO3θ3 (4) Here, To is the component of the resultant tension Tt in the direction perpendicular to the line segment connecting the roll center P and the rotation fulcrum 12A, as shown in FIG. In other words, it is an effective component as a moment). Further, the following relationship holds true between the composite tension Tt, the output tension T2, and the input tension T1. Tt2=(T2 T+Sinθ5)2+(T+cos
θ5)2 (5) Here, θ5 is the angle that the inlet tension T1 makes with the vertical line, as shown in FIG. As is clear from FIGS. 2 to 4, when the thickness t of the strip 8 changes, the roll 20 immediately before and the roll 1
Since the winding angles θ11 and θ12 (see FIG. 3) change, the direction of the resultant force also changes, causing an error. Furthermore, when the weight W of the strip 8 changes, the weight detected by the load cell 16 changes, causing an error. Therefore, in the present invention, these are corrected using the above relational expression. Among the parameters used in each of the above relational expressions, the values that are specified in the actual device are I In, 11,
R+, R2, D, E, μ, θ4, and θ5, but since there are too many unknown parameters and it is impossible to calculate the outlet tension T2, the following approximation is performed. In other words, as is clear from equation (1), the outlet tension T2 is the sum of the inlet tension TI and the loss, but as is clear from trial calculation using a normal device, the loss is equal to the inlet tension T1. Since it is much smaller and within a few percent, even if the outlet tension T2 and the inlet tension T1 are almost equal, a large error will not occur. Therefore, by setting T2 = T1, the following relationship holds true. . θ 1 / 2 = θ 2 + θ 5, ", θ2 =
(θ, /2)-θ5...(6)θ3;θ1+θ4-θ
5 - (θ+/2) 90° ... (7) Here, θ1
As shown in FIG. 2, is the angle formed by the inlet tension T1 and the outlet tension T2, that is, an internal angle. In this way, since the values of θ2 and θ3 can be known, the pure tension cuff 2' can be obtained by removing the error from equations (4) and (5) using the following equation. Tt' = T2" (1-sinθ5)2+T2
"CO32θ5 = T2" ((1-sinθ5)2+cos2θ5
) T2 ” = Tt '/(2(1-sinθ5))・
... (8) ... (9) Therefore, the exit tension T2 applied to the strip 8 may be controlled so as to satisfy the following equation. T2=T2' +W (l to/2+l ++)x
cos (θ2-θ3)+W-BL+ML...(1
0) Therefore, an arithmetic unit that calculates equations (9) and (10) is provided, and the width b of the strip, the thickness 1. By setting the w degree (material type) ρ, it is possible to eliminate errors in rotational force due to the winding angle on the roll, bend loss, and error due to the weight of the strip, making it possible to control tension with high precision. . Note that since the interior angle θ1 changes slightly depending on the size of the plate thickness t, it is also possible to correct this. Diameter D of detection roll 10 (=2R2)=7621 m,
Roll shaft radius R+=37.5mm, roll and bearing weight W=500kr, bearing friction coefficient μ=0°0028,
Young's modulus of strip 8 E=19700+qr/in'
(For SUS304 (1')) or 20400kg
/1m' (for SU3430), distance in the height direction between roll center P and rotation fulcrum 12A 11 = 19011m
(See Figure 2), also the horizontal distance β2 = 2201
(see Fig. 2), horizontal distance J2a between the rotation fulcrum 12A and the load cell 16 = 470u (see Fig. 2), internal angle θ
+=:=100”, θ number = 49.2°, previous roll 2
0 and the detection roll 1o in the horizontal direction J2<=844.
3u (see Figure 3), also the distance in the height direction Jls = 4
As 00+o+ (see Figure 3), plate width b = 1n,
For the case of unit tension 10=0゜5 kg/ad,
Standard tension T43 (=t. xb xt) (kg), Bendross BL (lc
g), rotating shaft friction loss ML (聰), total loss (kg),
Same (%), detection error due to loss (=1/2・(T2TI
)/T 2
．． When calculating for the case of 2.0.5.1.0.1.5.2.011, the results shown in Table 1 (for SUS304) and Table 2 (for SU3430) below were obtained. Ta. When the above calculation results are illustrated for the case where the plate width b=1n, the results are as shown in FIG. Therefore, by having an error rate graph as shown in FIG. 5 for each type of plate width, highly accurate correction can be performed quickly. Embodiments Hereinafter, embodiments of the present invention applied to, for example, tension control on the entrance side of a continuous annealing furnace will be described in detail with reference to the drawings. As shown in FIG. 1, this embodiment includes a load cell 16 similar to that of the conventional example. The force F not detected by this load cell 16 is transferred to the A/D converter 30'''C''A/D
After being converted, it is input to the arithmetic unit 32. This computing unit 3
2 is obtained by calculating the equations (9) and (10) above according to the known parameters and the width b, thickness t, and density ρ (strip type) of the strip 8 set from the outside. I! l Calculate tension T2. The output of the calculator 32 is input to a comparator 34, where it is compared with a reference tension Ts, which is a target value obtained by multiplying the unit tension ts by the board width and the board thickness t. The difference is input to the motor control circuit 36. The output of the motor control circuit 36 is outputted to, for example, the drive motors 38, 40 of the two priddle rolls 18 and 20,
Out l17! The rotation of the drive motors 38 and 40 is controlled so that the tension T2 becomes the reference tension Ts. In the above embodiment, the present invention is applied to tension control on the entrance side of a continuous annealing furnace, but the scope of application of the present invention is not limited to this, and tension control on the exit side of a continuous annealing furnace (
In this case, in contrast to the embodiment, it is clear that the present invention can be similarly applied to tension control in a rolling line (the most upstream roll closest to the annealing furnace is the detection roll) and a rolling line.

【Effect of the invention】

As explained above, according to the present invention, the winding angle difference caused by the difference in plate thickness, the difference in rotational force due to bend loss, the difference in the force applied to the load cell caused by the difference in the weight of the strip, etc. are corrected, and the strip The tension applied to the can be determined with high accuracy. Therefore, it has the excellent effect of making it possible to perform tension control with high precision.

[Brief explanation of the drawing]

FIG. 1 is a process diagram including a partial block diagram showing the configuration of an embodiment of the strip tension control device according to the present invention. FIG. 3 is a front view showing the relationship between the front roll and the rear roll; FIG. 4 is a front view illustrating the method of determining the loss due to friction of the rotating shaft; FIG. 5 is a line section showing an example of an error rate graph, and FIG. 6 is a front view showing a tension detection method in a conventional strip tension control device. 10...Direction change roll, 12...Bearing arm, 16...Load cell, b...Plate width, t...Plate thickness, ρ...Density, BL...Bend loss, ML...・Rotating shaft friction loss.

Claims (1)

[Claims] (1) A strip tension control device that detects tension when the strip passes over a direction change roll and controls it to a target value, comprising: means for detecting a moment applied to a rotational support portion of the direction change roll; A correction means that corrects the value according to the width, thickness, and type of the strip to eliminate the effects of errors in rotational force due to the winding angle on the direction change roll and bend loss, and errors due to the weight of the strip. A strip tension control device comprising: .