Separate Drive Control for Rolling Line Speed Synchronization
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Solution Overview
Problem
In wire rolling, maintaining precise rotational speed ratios between roll stands is challenging due to wear and real load moments, leading to potential wire breakage or loop formation, especially when transitioning between rolling sections.
Innovation Solution
Each roll stand on a rolling line is equipped with a separate drive and rotational speed regulator, with a supplementary value based on expected real load moments being fed to all regulators at a predetermined time to compensate for speed drops and maintain synchronicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common large motor drives all roll stands via a mechanical transfer gearbox, then the rotational speed ratio is kept constant, but wear of individual rolling rings requires exchange or regrinding of all rolling rings, making the process time-consuming and costly
Solution Approach 1:
The patent divides the drive system into separate independent drives for each roll stand, with each drive having its own motor and gearbox. This segmentation allows individual rolling rings to be replaced or reground independently without affecting other roll stands, resolving the contradiction by enabling maintenance of one component without requiring shutdown of the entire system.
Solution Approach 2:
The patent implements dynamic speed regulation for each separate drive, allowing the rotational speeds of individual roll stands to be adjusted independently. This dynamic control compensates for wear of rolling rings by modifying speed ratios in real-time, maintaining constant material flow while avoiding the need to replace all rolling rings when one wears.
2Adaptability or versatility
If each roll stand is driven by a separate drive with independent speed regulation, then rolling speeds can be set independently to compensate for wear, but real load moments cause drops in rotational speed, leading to asynchronicity and potential wire breakage or loop formation
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the actual rotational speeds of all roll stands and compares them with the prescribed speed ratios. When deviations are detected (such as speed drops due to real load moments), the system automatically adjusts the speed of individual drives to restore synchronicity, thereby preventing wire breakage and loop formation while maintaining the adaptability to compensate for wear.
Solution Approach 2:
The patent applies preliminary anti-action by detecting the onset of real load moments (when material enters the rolling gap) and preemptively adjusting the speed of affected roll stands before significant asynchronicity develops. This prevents the harmful effects of speed deviations, such as wire tension, compression loads, and loop formation, while preserving the ability to independently adjust speeds for wear compensation.
3Reliability
If rotational speed ratios are strictly maintained, then wire breakage and loop formation are prevented, but any wear or speed variations require immediate adjustment of all roll stands, reducing productivity
Solution Approach 1:
The patent employs dynamic speed regulation that allows temporary, localized adjustments to individual roll stand speeds in response to wear or load variations. The system maintains the prescribed speed ratios through continuous adjustment rather than requiring all stands to be stopped and readjusted, thus preserving both reliability (preventing wire breakage) and productivity (maintaining operational continuity).
Solution Approach 2:
The patent changes the operational parameters (rotational speeds) of individual drives dynamically based on real-time conditions such as wear and load moments. By allowing flexible parameter adjustments within the control system, the patent maintains the required speed ratios for reliability while avoiding production stoppages, thereby ensuring continuous operation and high productivity.
Data Source
AI summary
A method for machining rolled stock (6) in a rolling train (2), the train including at least one rolling block (20, 20a, 20b) having at least two rolling stands (4) with each stand including at least one roll (13). Each rolling stand (4) has a separate drive (8) with a speed controller (14) for its roll (13). A time (tzw) that is dependent on the point in time (tB) that an actual loading moment is applied to the drive (8) of the first rolling stand (4) of the rolling block (20, 20a, 20b), for controlling the speed of the drive (8). An additional value (ZW), dependent on an expected actual loading moment, is fed to the speed controller (14) of each drive (8). Also, a rolling train (2) for machining rolled stock (6), is disclosed having the features above and having an open-loop/closed-loop control unit (24), in which software for the method is implemented.