JPS6144925B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for suppressing tension fluctuations in a process line.

Process line For example, in a continuous annealing line for steel strips, loop cars are installed at the entrance and exit sides of the furnace so that the annealing furnace serves as the center section and the speed can be kept constant for continuous sheet passing. , a looper such as a loop tower will be installed.

Among the loopers, especially the loop tower, a large amount of steel strip is alternately stretched between a group of rolls fixedly mounted on the upper part of the structure and a group of rolls mounted on a carriage that can be moved up and down. This steel strip is combined with a bridle roller that controls tension, and the storage amount of the steel strip in the looper, that is, the loop capacity, is adjusted by moving the carriage up and down.

Normally, the looper on the entry side is set to have the maximum storage capacity during operation, and when decelerating on the entry side, the carriage rises to maintain a constant sheet threading speed in the center section.

When such a deceleration operation is performed relatively slowly, the carriage and roll follow smoothly, but stopping at the entry section
For example, when a sudden break occurs in the steel strip, in a conventional looper, the inertia of the roll itself causes the roll to continue rotating at the original circumferential speed. There is a risk that slippage may occur between the loopers and cause scratches on the plate surface, or tensile force may be generated on the steel strip, causing secondary breakage within the looper.

This invention prevents plate breakage within the looper when the loop position changes by driving the looper roll with a motor.

Now, Figure 1 shows an example of a looper, and in the figure Br ₁
is its entrance bridle roller, Br ₂ is its exit bridle roller, 1, 3...n is a fixed pivot roll group, 2, 4...m is a roll group pivoted on the carriage C, and the center section The side looper roll n only needs to follow very slight accelerations and decelerations at the center section, but the looper roll 1 is connected to the entry side bridle roller Br ₁ , which is connected to the steel strip on the entry side. Depending on the situation, it is necessary to make a rapid stop, and as a result, there is a concern that the plate may break inside the looper as described above.

In this invention, the looper rolls 1, 3...n are driven by motors with capacities commensurate with their respective acceleration/deceleration rates, thereby avoiding accidents such as plate breakage even during rapid stops, and the position of the looper during acceleration/deceleration. This suppresses tension fluctuations in the steel strip caused by fluctuations in the steel strip to a minimum, ensuring stable line operation.

As shown in Fig. 1, each looper roll 1, 2...n
The entrance speed of the steel strip S, which is alternately passed in large quantities, is
Ve, the exit speed is Vd, and Vc is the looper speed, then the speed difference between the entrance and exit sides is Ve-Vd=(n-1)Vc Here, n is given by the number of fixed pivot rolls, so the entrance side The rotation speeds of the fixed looper rolls, which are indicated by number subscripts in order of proximity to the bridle roller Br ₁ , are: N ₁ = 1/πDVe N ₂ = 1/πD (Ve−Vc) _No = 1/πD {Ve− (n-1)Vc}=1/πDVd Here, D is calculated by the roll diameter, and therefore, by detecting Ve and Vd, the number of revolutions of each roll can be calculated.

Therefore, you may choose to drive each looper roll individually with a motor at such a rotation speed, or attach a differential gear to each roll and drive it with a single motor, but in the latter case, the motor and Although only one power source is required, the mechanical equipment for differential gears is not necessarily simple; the former requires more motors and power sources, but requires less mechanical equipment.

Fig. 2 shows an example of a control circuit when using each roll motor, in which PLG is a pulse generator, P is a looper speed Vc detector, M is a multiplier, A is an adder, and D/A is
It is a DA converter, and the output shown by the arrow of each DA converter is used as a setting signal for each roll motor control circuit, so even if the entry bridle roller suddenly stops, the corresponding rotation speed will be maintained. Since each looper roll is driven by the looper roll, there is no risk of plate flaws due to slippage between the looper roll and the steel strip S, or plate breakage within the looper due to excessive tension.

The above-mentioned effect due to the sudden stop of the entry-side bridle roller is most severe on the adjacent looper roll 1, so the above is applied only to the looper roll 3 adjacent to it, which is closer to the bridle roller. Since the desired effects of the present invention can be achieved satisfactorily by simply adding additional control, the total control in the above-mentioned specific example is not essential.

In this invention, by driving the looper roll, it is possible to reduce the delay in acceleration and deceleration due to GD ² of the roll. Therefore, even in the case of a rapid stop such as when a plate breaks, the acceleration and deceleration of the looper roll follows, thereby making it possible to prevent secondary breakage within the looper.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a looper, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. 1, 3...n...fixed roll, 2, 4...m...movable roll, C...carriage, _Br1 , _Br2 ...bridle roller.

Claims (1)

[Claims] 1 A looper that alternately threads the steel strip in multiple layers between a fixedly pivoted roll group and a roll group pivoted on a carriage that can move up and down with respect to the roll group was used to control the tension acting on the steel strip. In a process line including a bridle roller, at least one roll close to the input bridle roller of the roll group of the looper is driven at a circumferential speed corresponding to the speed difference between the input and output sides of the looper. Suppression method.