Rolling Mill Backup Roll Thrust Point Identification Under Kiss Load
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Solution Overview
Problem
Existing methods for identifying thrust counterforce working point positions in rolling mills are limited, requiring calibration equipment and being feasible only during roll changes, making it difficult to accurately determine these positions outside of specific maintenance times.
Innovation Solution
A method that involves causing thrust forces to act between rolls by changing friction coefficients or inter-roll cross angles, allowing for measurement of thrust counterforces and backup roll counterforces, and using equilibrium expressions to identify the thrust counterforce working point positions without the need for calibration equipment during roll changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration equipment and roll change timing are required to identify thrust counterforce working point positions, then measurement accuracy can be ensured, but the identification can only be performed during maintenance times and not during normal operation
Solution Approach 1:
The rolling mill system uses its own operational parameters (thrust forces, counterforces, and equilibrium expressions) to identify the working point positions without requiring external calibration equipment. The system performs self-diagnosis by measuring forces during normal rolling operations and solving equilibrium equations, enabling continuous identification without stopping production or requiring specialized calibration tools.
Solution Approach 2:
The method pre-establishes the equilibrium conditional expressions that relate thrust forces, counterforces, and working point positions. By having these mathematical relationships prepared in advance, the system can immediately calculate working point positions using real-time force measurements during normal operation, eliminating the need for calibration equipment and maintenance timing constraints.
2Productivity
If thrust forces are measured during rolling operations with multiple rolls, then the system can operate continuously, but frictional forces from perpendicular loads on backup rolls contaminate the thrust counterforce measurements
Solution Approach 1:
The measurement system is segmented into separate measurement points: thrust counterforces are measured on rolls that do not carry perpendicular loads (work rolls or intermediate rolls), while backup roll counterforces are measured separately at their reduction support positions. This segmentation allows the system to obtain pure thrust force measurements without contamination from frictional forces generated by perpendicular loads on backup rolls.
Solution Approach 2:
The method extracts the pure thrust force component by measuring counterforces only on rolls that are not subjected to perpendicular loads from pressing-down devices. By taking measurements exclusively on work rolls or intermediate rolls where only thrust forces act, the system extracts the desired thrust counterforce signal while excluding the harmful frictional contamination that would be present on backup rolls.
Data Source
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Figure 1B
Figure 2A
AI summary
There is provided a method for identifying thrust counterforce working point positions of backup rolls of a rolling mill of four-high or more, the method including: a step of changing at least either friction coefficients and inter-roll cross angles between the rolls with an unchanged kiss roll load to cause thrust forces at a plurality of levels to act between the rolls, and measuring thrust counterforces in a roll-axis direction acting on rolls forming at least one of roll pairs other than a roll pair of the backup rolls and measuring backup roll counterforces acting in a vertical direction on the backup rolls at reduction support positions at the plurality of levels of thrust force in a kiss roll state; and a step of identifying, based on the measured thrust counterforces acting on the rolls, thrust counterforce working point positions of thrust counterforces acting on the backup rolls, using first equilibrium conditional expressions relating to forces acting on the rolls and second equilibrium conditional expressions relating to moments acting on the rolls.