Work Roll Balance Force Control for Inter-Roll Slide Suppression
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Solution Overview
Problem
Existing rolling mill technologies face challenges in preventing inter-roll slide during thin strip rolling, as the roll balance force becomes excessive, potentially damaging components like bearings, especially when kiss roll occurs.
Innovation Solution
A work roll balance force setting method that determines the kiss roll load and traction coefficient based on the mill longitudinal rigidity coefficient and rolling conditions, resetting the balance force to prevent excessive inter-roll slide without damaging components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If roll balance force is increased to prevent biting failure, then biting reliability is improved, but inter-roll slide increases causing component damage
Solution Approach 1:
The system calculates the required roll balance force in advance based on rolling conditions (strip thickness, width, temperature, material grade) before biting occurs. By determining the optimal balance force beforehand using the relationship Pb = f(Pr, K, μ), the system prevents both biting failure and excessive inter-roll slide, avoiding component damage while ensuring reliable biting.
Solution Approach 2:
The invention dynamically adjusts the roll balance force parameter based on changing rolling conditions. By using the formula Pb = Pr × (K/(2μ)) where Pr is rolling load, K is mill rigidity coefficient, and μ is friction coefficient, the system optimizes the balance force parameter to prevent inter-roll slide while maintaining biting reliability under various operating conditions.
2Manufacturing precision
If work rolls with smaller radius are used to roll thinner strips, then strip thickness reduction is improved, but load capacity of drive spindle decreases
Solution Approach 1:
The invention introduces intermediate rolls as a mediator between the drive spindle and small-diameter work rolls. The intermediate rolls have larger diameter and are directly driven by the drive spindle, providing sufficient load capacity. They transfer rolling torque to the small work rolls through inter-roll contact, enabling the use of small work rolls for thin strip production while maintaining drive spindle load capacity.
Solution Approach 2:
The system adds an intermediate layer (intermediate rolls) to the rolling mill structure, creating a two-stage torque transmission path. This dimensional addition to the roll configuration allows decoupling of the drive spindle load capacity requirement from the work roll diameter, enabling small work rolls to be used without compromising drive system strength.
3Power
If roll balance force is increased to transfer necessary torque to work rolls, then torque transfer is improved, but kiss roll causes excessive balance force damaging components
Solution Approach 1:
The system calculates the optimal roll balance force in advance based on rolling conditions before kiss roll occurs. By using the relationship Pb = Pr × (K/(2μ)) to determine the required balance force beforehand, the system ensures sufficient torque transfer to work rolls while preventing excessive balance force that would damage components during kiss roll events.
Solution Approach 2:
The invention implements a control system that monitors rolling conditions and adjusts roll balance force accordingly. By continuously comparing actual rolling parameters with target values and adjusting Pb in real-time based on feedback from sensors measuring strip thickness, tension, and roll position, the system maintains optimal torque transfer while preventing component damage during kiss roll.
Data Source
AI summary
Work roll balance force setting method of rolling mill. Determine kiss roll load Pk, rolling load Pr, and rolling torque Tr of work rolls relative to work roll angle θx of tip position of rolled material between start and completion of biting of rolled material using mill longitudinal rigidity coefficient K and rolling condition. Determine traction coefficient μrt between work and intermediate rolls, and maximum value μrtmax of μrt in relation to θx when hypothetical work roll balance force Pb is applied from sum P of Pk, Pr, and Pb, and Tr between start and completion of biting. Compare tolerated value μrter of μrt with μrtmax. Work roll balance force at start of biting reset to equal to or larger than required when μrt assumes maximum value μrtmax, and equal to or smaller than limit based on strength of rolling mill, when μrter is equal to or larger than μrtmax.