JPH0661573B2 - Pinch roll tension control device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a pinch roll tension control device that prevents slippage between a rolled material and a pinch roll in a rolling facility such as a wire rod.

[Technical Background of the Invention and Problems Thereof] In the wire rod rolling mill, as shown in FIG. Placed in a ring on top of.

The exit speed of the finish rolling mill 1 is usually high speed of 60 m / sec or more, and the material is thin. Therefore, in order to allow the material to pass stably, the speed of the pinch roll 2 is controlled so that an appropriate tension is applied to the material. I need to give it.

As a control system of the pinch roll drive motor 5 for this purpose, two methods of drooping characteristic speed control and current control are used.

FIG. 3 shows an example of a conventional pinch roll tension control device.

In FIG. 3, 13 is a lead rate setting device, and the lead rate α is set via the multiplier 12 to the set speed v ₀ set by the speed setting device 11 until the material leaving the rolling mill bites into the pinch rolls. by adding the .alpha.v ₀ multiplied by (1 + α) v ₀ as the speed reference, the speed controller 14, controls the speed of the pinch roll motor 5 via a current controller 15. 16 is a speed detector. As the initial setting value of the lead rate α, a value corresponding to the advanced rate of the finish rolling mill is usually set.

When the material is caught in the pinch roll 2, the tension control device 19 starts tension control.

That set tension T _REF set in the tension setting unit 17, the tension - is converted into a set current I _REF considering such by connexion roll diameter to current converter 18, butted against the current reference I _a to the output of the speed controller 14 Then, the deviation is amplified by the tension controller 19, and the output signal D by PI control or P control is added to the speed reference (1 + α) v ₀ .

As a result, the speed standard of the pinch roll, which was increased by the lead rate α until the material was caught in the pinch roll, was:
When the material is caught in the pinch roll and the current reference I _a becomes larger than the set current I _REF , the output signal D of the tension controller 19 operates in the decelerating direction, and when the current reference I _a is smaller than the set current I _REF , the speed increasing direction. To exert a constant tension on the material.

However, if the lead ratio α is set too high and slippage occurs between the material and the pinch roll, the relationship between the current reference I _a and the pinch roll speed v is broken, and the pinch roll speed v increases and the current reference I _a increases. Reduces the tension controller
The output D of 19 acts to further increase the speed of the pinch roll and further increases the slip between the pinch roll and the material, which may lead to wear of the pinch roll and possibly burnout thereof. . If the lead ratio of the pinch roll is set to a low value in advance, when the rolled material bites into the pinch roll, the rolled material cannot withstand the compressive force with the finish rolling line and forms a loop. Therefore, the lead ratio of the pinch roll is set (high) so that it normally acts on the pulling side.

[Object of the Invention]

The present invention provides a tension control device for a pinch roll that reduces the speed reference when the output D of the tension controller saturates in the direction of acceleration, thereby preventing slippage between the material and the pinch roll. It is an object.

[Outline of Invention]

The present invention includes a speed controller that controls the speed of the drive motor according to the speed reference, and a tension controller that increases or decreases the speed reference according to the deviation between the set current corresponding to the set tension and the motor current. In the pinch roll tension controller,
It is equipped with a saturation detector that detects that the output of the tension controller is saturated in the acceleration direction, and a constant converter that lowers the speed reference according to the output of the saturation detector. It prevents slipping.

Example of Invention

 One embodiment of the present invention is shown in FIG.

In FIG. 1, reference numeral 21 is a saturation detector for detecting that the output D of the tension controller 19 is saturated, and when the saturation detector 21 detects the saturation of the output D, the lead rate setting device via the constant converter 20. The read rate α set in 13 is reduced, and the others are the same as in FIG. 3 of the related art.

The above-mentioned saturation value is set as a constant speed reference in the speed-up direction which is determined by the rating of the motor, etc. When the output D of the tension controller 19 exceeds this saturation value, the saturation detection signal corresponding to the deviation is converted into a constant converter. It is output to 13 to reduce or cut the lead rate α to lower the speed reference of the pinch roll, thereby preventing slipping between the rolled material and the pinch roll. But,
It is considered that when the lead rate α is rapidly changed, it has a considerable adverse effect on the rolled material. Therefore, when the lead rate α is changed, that is, when the speed reference is increased or decreased, the lead rate α is not rapidly changed stepwise but is changed gradually. By giving the gradual rate of change in this way, it is considered that the adverse effect on the rolled material due to the rapid speed change is minimized.

Although the current reference is used to detect the electric motor current in the above embodiment, the electric motor current may be directly detected and used.

〔The invention's effect〕

As described above, according to the present invention, a slip occurs between the material and the pinch roll, and the current reference value of the pinch roll motor falls below the set current set corresponding to the required tension, whereby the tension is increased. When the output voltage of the controller is saturated, the lead rate of the set speed is lowered to lower the speed reference, so that the progress of the slip is stopped and the pinch roll is prevented from being worn or burned.

[Brief description of drawings]

FIG. 1 is a control system diagram showing an embodiment of the present invention, FIG. 2 is a layout diagram showing a general configuration of a wire rod rolling mill including a pinch roll, and FIG. 3 is a conventional pinch roll tension control device. It is a control system diagram which shows an example. 1 …… Finishing rolling mill 2 …… Pinch roll 3 …… Raining head 4 …… Conveyor 5 …… Pinch roll motor 11 …… Speed setter 12 …… Multiplier 13 …… Lead rate setter 14 …… Speed control Controller 15 …… Current controller 16 …… Speed detector 17 …… Tension setter 18 …… Tension-current converter 19 …… Tension controller 20 …… Constant converter 21 …… Saturation detector

Claims (1)

[Claims] 1. A speed controller for controlling the speed of a drive motor according to a speed reference, and a tension controller for increasing or decreasing the speed reference according to a deviation between a set current and a motor current corresponding to a set tension. In a tension control device for a pinch roll, a saturation detector that detects that the output of the tension controller is saturated in the acceleration direction, and a constant converter that lowers the speed reference according to the output of the saturation detector are provided. A tension control device for a pinch roll characterized in that