Rolling Mill Chock Position Control for Thrust Force Balance

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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 and inter-roll cross angle corrections.

Innovation Solution

A rolling mill with a measurement apparatus to measure rolling direction forces on both work and drive sides, a pressing apparatus to adjust roll chocks, and a position control unit to synchronize the positions of roll chocks relative to a reference roll, ensuring rolling direction force differences fall within an allowable range, thereby reducing inter-roll thrust forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If thrust counterforce measurement is performed during rolling to control reduction position, then reduction leveling control can be performed, but measurement accuracy deteriorates due to changing rolling conditions and friction coefficients

Engineering Contradiction:
Improvereduction leveling control accuracyVSAvoidthrust counterforce measurement accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by measuring the thrust counterforce before rolling starts (during the setup phase) rather than during rolling. This allows obtaining accurate measurement values when rolling conditions are stable and friction coefficients are consistent, avoiding the measurement errors that occur when conditions change during actual rolling operations

Inventive Principle:
Principle #10Preliminary action

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

Engineering Contradiction:
Improvezigzagging control accuracyVSAvoidroll skew angle measurement accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent extracts the measurement from the problematic rolling environment by measuring thrust counterforce during the setup phase before rolling begins, rather than measuring roll skew angle during rolling when vibration and position fluctuations occur. This separates the measurement process from the harmful dynamic conditions

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If roll chock positions are adjusted to eliminate inter-roll cross angles, then thrust force reduction can be achieved, but device complexity increases due to additional measurement and control systems

Engineering Contradiction:
Improvethrust force between rollsVSAvoidmeasurement and control system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies self-service by using the rolling mill's own thrust counterforce measurement capability during setup to automatically determine and adjust roll chock positions. The system uses its inherent measurement function rather than requiring external complex measurement equipment, making the control system self-sufficient

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3804870B1Rolling mill and method for setting rolling mill
Publication Date: 2023.05.03 NIPPON STEEL CORPORATION
  • EP3804870B1 patent drawingFigure 1
  • EP3804870B1 patent drawingFigure 2A
  • EP3804870B1 patent drawingFigure 2B

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 are provided on either one of an entrance side and an exit side in a rolling direction of the roll chocks, and that press the roll chocks in the rolling direction; driving apparatuses that are provided so as to face the pressing apparatus in the roll chocks, and 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 that is a difference between a rolling direction force on the work side and a rolling direction force on the drive side so that the rolling direction force difference of each roll is a value within an allowable range.