Rolling Mill Chock Position Control for Thrust Force Balancing
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Solution Overview
Problem
Existing rolling mill technologies face challenges in accurately measuring and controlling thrust forces between rolls, leading to zigzagging and camber issues due to asymmetric deformation and changing friction coefficients, which complicates reduction leveling control and inter-roll cross angle corrections.
Innovation Solution
A rolling mill setup that includes a measurement apparatus for rolling direction forces, a pressing apparatus to adjust roll chocks, and a position control unit to set rolling direction force differences within an allowable range by designating a reference roll and adjusting the positions of other rolls accordingly, ensuring stable production without zigzagging or camber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thrust counterforce measurement is performed during rolling to identify asymmetric deformation, then reduction leveling control can be performed, but measurement accuracy deteriorates due to changing working point characteristics with varying rolling conditions
Solution Approach 1:
The patent performs thrust counterforce measurement before rolling starts (during idle rotation) to establish baseline characteristics, and uses this preliminary data to correct measurements taken during rolling. This preliminary measurement captures the static thrust characteristics without the interference of dynamic rolling conditions, enabling accurate identification of asymmetric deformation.
Solution Approach 2:
The system uses the thrust counterforce measurement results to feedback-adjust the reduction position settings. By measuring the thrust counterforce during idle rotation and calculating the asymmetric deformation characteristics, the system can pre-adjust the reduction positions to compensate for the identified asymmetry, thereby improving reduction leveling control accuracy.
2Manufacturing precision
If roll skew angle is measured using distance sensor to calculate thrust force, then zigzagging control can be performed, but measurement accuracy deteriorates due to roll vibration and chock position fluctuations
Solution Approach 1:
The patent introduces thrust counterforce measurement as an intermediary parameter to indirectly determine roll alignment issues. Instead of directly measuring the difficult-to-obtain roll skew angle during vibration, the system measures the thrust counterforce which reflects the same alignment problems but can be measured more accurately during idle rotation when vibrations are absent.
Solution Approach 2:
The system replaces direct mechanical measurement of roll position (using distance sensors during operation) with a force-based measurement approach. By substituting position measurement with thrust force measurement during idle rotation, the system avoids the interference of mechanical vibrations and achieves more reliable data for zigzagging control.
3Manufacturing precision
If inter-roll cross angle correction is performed by position control of roll chocks, then relative positional deviation can be reduced, but thrust force elimination is insufficient due to bearing looseness and play
Solution Approach 1:
The system uses thrust counterforce measurement as feedback to evaluate the effectiveness of inter-roll cross angle correction. By measuring the thrust counterforce after position adjustment, the system can determine whether the correction was sufficient and make further adjustments if needed, ensuring reliable thrust force elimination despite bearing play.
Solution Approach 2:
The patent performs inter-roll cross angle correction before rolling starts by measuring thrust counterforce during idle rotation and adjusting roll chock positions accordingly. This preliminary correction eliminates thrust forces before the rolling process begins, preventing asymmetric deformation from occurring in the first place.
Data Source
AI summary
A rolling mill of four-high or more is provided that includes: measurement apparatuses that adopt any one roll as a reference roll, and measure at least rolling direction forces acting on roll chocks on a work side and roll chocks on a drive side of each roll other than a backup roll; pressing apparatuses that press the roll chocks in the rolling direction; driving apparatuses that move the roll chocks in the rolling direction; and a position control unit that fixes a rolling direction position of the roll chocks of the reference roll as a reference position, and drives the driving apparatuses to control the positions in the rolling direction of the roll chocks based on a rolling direction force difference so that the rolling direction force difference of each roll is a value within an allowable range.