Rolling Line Linear Drive Control for Stable Strip Tension
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Solution Overview
Problem
Existing methods for step rolling, such as those described in EP 3 097 992 A1 and DE 38 07 399 A1, face challenges with long response and control times, requiring extensive empirical data for process parameter calculation, and struggle to achieve smooth thickness transitions due to variable tensile forces applied by work rolls.
Innovation Solution
A device utilizing a linear drive to apply and regulate tensile stress on rolling stock, allowing for dynamic control of tensile stress across the rolling stock's cross-section, independent of drive speed, and incorporating force measuring bearings and servo motors for precise torque adjustment, enabling efficient thickness reduction and optimized flow in the roll gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If control is based on measurement of inlet and outlet side belt speed and strip thickness, then thickness transitions can be achieved, but response and control times are too long
Solution Approach 1:
The patent applies preliminary action by pre-calculating the required reel speeds based on the desired final strip thickness profile before the rolling process begins. This allows the control system to anticipate required adjustments rather than reacting to thickness measurements after they occur, thereby reducing response and control times while maintaining thickness transition quality.
2Loss of time
If reel speeds are controlled according to pre-calculated data, then control time is reduced, but a large number of empirical data must be recorded first
Solution Approach 1:
The control system applies self-service by automatically determining the required reel speeds based on real-time measurements of inlet and outlet strip thicknesses, eliminating the need for extensive pre-recorded empirical data. The system calculates and adjusts process parameters autonomously during operation, reducing setup complexity while maintaining fast control response.
3Ease of operation
If forces applied by work rolls are kept constant, then control is simplified, but tensile forces cannot be optimized for different strip sections
Solution Approach 1:
The patent applies dynamics by making the reel speeds variable and adjustable during the rolling process, allowing tensile forces to be optimized for different strip sections as needed. The system dynamically changes reel speeds based on real-time thickness measurements, enabling precise thickness transitions while maintaining relatively simple control logic for the work rolls.
4Stability of the object's composition
If the section of strip under tension is kept small, then structure balance is improved, but control of tensile stress becomes more difficult
Solution Approach 1:
The patent applies feedback by continuously measuring the inlet and outlet strip thicknesses and using these measurements to adjust the reel speeds, thereby controlling the tensile stress in the strip. This closed-loop control system maintains small tension zones for structural balance while automatically adjusting parameters to keep control complexity manageable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for significantly improved rolling results by maintaining constant tensile stress, reducing thickness transitions, and enhancing the quality of rolled stock, with the ability to regulate tensile stress based on real-time data and adjust contact pressure for balanced deformation.
Implementation Method 1
at least one linear drive downstream of the pair of rollers in the rolling direction, which can apply tensile stress to the rolled stock together with the pair of rollers
Implementation Method 2
with means for detecting the tensile stress
Data Source
Figure 1
Figure 2
Figure 3a~4b
AI summary
The invention relates to a device for rolling, in particular for stepped rolling, of material (8) to be rolled, comprising at least one roll pair (1, 2) and at least one linear drive (5), which is arranged downstream of the roll pair (1, 2) in the rolling direction and, together with the roll pair (1, 2) can apply tensile stress to the material 8 to be rolled, and comprising means for detecting the tensile stress. In order to provide an improved method for flexibly rolling material to be rolled, the roll device is characterised by means for detecting the tensile stress and by a controller for controlling the drive output of the linear drive (5) on the basis of the ascertained tensile stress, in order to selectively vary the tensile stress applied to the material (8) to be rolled, or to keep the tensile stress constant in the case of changing drive speeds downstream of the roll nip. The invention also relates to a method for rolling the material (8) to be rolled using such a device.