Method and apparatus for detecting roll eccentricity utilizing pulse generator in rolling mill

Abstract

The present invention relates to a method and an apparatus for detecting a roll eccentricity element of a rolling mill, which is occurred by the difference between a rotation center and a geometric center of a roll. The present method for detecting a roll eccentricity of a rolling mill comprises the steps of: inputting data with respect to a rolling load from the rolling mill, a pulse generating signal from a pulse generator, input and output signals of the steel plate, respectively; determining whether input signal of the steel plate and marker pulse signal of the pulse generator are being inputted; storing the rolling load of the rolling mill corresponding to respective sample pulse signals of the pulse generator in a buffer; calculating alterations of the rolling load by subtracting average rolling load from the rolling load being stored in the buffer; detecting eccentric fundamental wave and radio frequency elements by performing non-linear curve fittings to alteration signal of the rolling load; and determining whether output signal of the steel plate is being inputted and when the output signal is being inputted, detecting procedure is terminated and when the output signal not being inputted, it is returned to the step of storing and the subsequent procedure is repeatedly performed. The present invention is capable of accurately detecting roll eccentricity elements to eccentric fundamental wave and radio frequency elements, using a pulse signal of the pulse generator and a rolling load signal of a load cell. Also, such detection of the roll eccentricity can be performed in reliability and durability, even in severe working conditions of the rolling mill.

1 . A method for detecting roll eccentricity in a rolling mill which is caused by a lack of concentricity between the rotation center and the geometric center of the roll using a pulse generator, comprising the steps of: 
 a) inputting data with respect to a roll force of the mill, a pulse signal from the pulse generator, an input and an output signal of a steel material to be rolled;    b) determining whether the input signal of the material and a marker pulse signal from the pulse generator are inputted;    c) storing roll forces corresponding to respective sample pulse signals from the pulse generator in buffers;    d) calculating respective roll force variations by subtracting an average roll force from respective roll forces stored in the buffers;    e) detecting the fundamental wave and harmonics of the eccentricity by non-linear curve fitting signals corresponding to the roll force variations; and    f) determining whether the output signal of the material is inputted, wherein when the output signal is inputted, the detection process is terminated but otherwise, the steps of c)-f) are iterated.    
   
   
       2 . The method as set forth in  claim 1 , wherein the pulse generator generates one marker pulse and 64 sample pulses whenever the roll completes a rotation.  
   
   
       3 . The method as set forth in  claim 1 , wherein the harmonic is a second harmonic.  
   
   
       4 . The method as set forth in  claim 1 , wherein where the roll rotates once more than a set rotation number, the fundamental wave and harmonics of the eccentricity are detected after excluding first data collected when the roll rotates once from the data stored in buffers.  
   
   
       5 . The apparatus for detecting roll eccentricity in a rolling mill which is caused by a lack of concentricity between the rotation center and the geometric center of the roll using a pulse generator, comprising: 
 a circular clamp wheel to be rotated with the roll in a state that is coupled with the shaft of the roll, and in which multiple blades are fixedly installed with equal circumferential spacing;    multiple proximity sensors for sensing the blades of the clamp wheel and generating one marker pulse and multiple sample pulses per one rotation of the roll in a state wherein the sensors are separated from the clamp wheel by a predetermined distance; and    a signal processing unit for generating pulses of integer multiple of the blades by multiplying pulses output from the multiple proximity sensors.    
   
   
       6 . The apparatus as set forth in  claim 5 , comprising three proximity sensors, wherein a first and a second sensors detect blades that are separated from each other with equal circumferential spacing on one edge of the clamp wheel and generate multiple sample pulses for each rotation of the roll and a third proximity sensor detects one blade formed on the other edge of the clamp wheel and generates one marker pulse for each rotation of the roll.  
   
   
       7 . The apparatus as set forth in  claim 5 , wherein opposite ends of two semi-circular elements of the clamp wheel are hingedly coupled with each other and the other ends are coupled with each other by a buckle.