Nested Hydraulic Cylinder Actuator for Rolling Mill Edger Stroke Control
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Solution Overview
Problem
Existing edging stand systems for rolling mills, particularly those used in sheet trains, face challenges in achieving precise and quick adjustments of roller distance due to the limitations of electromechanical and hydraulic systems, which result in reduced control accuracy and increased maintenance costs, especially with longer stroke requirements.
Innovation Solution
A completely hydraulic actuation device comprising a cylinder group with an external 'controlled stroke' cylinder and an internal 'ON/OFF' cylinder, allowing for adjustable strokes ranging from 1800 to 2500 mm, enhancing precision and speed while maintaining stiffness and reducing maintenance complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single hydraulic cylinder with long stroke (1800-2500 mm) is used, then the adjustment stroke is sufficient for sheet trains, but the stiffness decreases due to hydraulic fluid compressibility, reducing control accuracy
Solution Approach 1:
The single long-stroke cylinder is segmented into multiple shorter-stroke cylinders arranged in series. Each cylinder maintains adequate stiffness while the series arrangement achieves the required total stroke through cumulative displacement, resolving the contradiction between stroke length and stiffness.
Solution Approach 2:
The cylinders are arranged in a nested or series configuration where multiple cylindrical actuators are positioned sequentially along the same axis. This nesting allows the system to achieve extended stroke while each individual cylinder maintains its stiffness characteristics, preventing the softening effect that occurs in single long-stroke cylinders.
2Speed
If electromechanical-hydraulic hybrid system with small-stroke plunger is used, then quick corrections are achieved, but the structure is considerably complicated and maintenance costs increase
Solution Approach 1:
The system merges multiple hydraulic cylinders into a unified actuation system, eliminating the need for separate electromechanical and hydraulic subsystems. This integration maintains the quick response of hydraulic actuation while simplifying the overall structure by removing complex mechanical transmission components.
Solution Approach 2:
The invention uses purely hydraulic actuation through multiple cylinders instead of electromechanical-hydraulic hybrid systems. This approach leverages the responsiveness of hydraulic systems while avoiding the structural complexity of combining electromagnetic motors, gearboxes, and hydraulic components, thereby reducing maintenance requirements.
3Device complexity
If electromechanical system with screw and nut is used, then the structure is simpler, but adjustments under load are not permitted and reaction times are long
Solution Approach 1:
The invention replaces electromechanical screw-and-nut mechanisms with direct hydraulic cylinder actuation. This substitution enables adjustments under load by utilizing hydraulic pressure to overcome rolling forces directly, while simultaneously reducing reaction time through the incompressible nature of hydraulic fluid transmission.
Solution Approach 2:
The patent substitutes mechanical transmission systems (screws, nuts, gearboxes) with hydraulic actuation systems. This replacement eliminates the need for complex mechanical mechanisms while achieving faster response times and the capability to perform adjustments under load, directly addressing the limitations of electromechanical systems.
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
The double cylinder group system enables faster and more precise adjustments with improved stiffness, reducing reaction times and maintenance costs, and is suitable for edging stands coupled with sheet trains, ensuring accurate control of material width and dynamic performance.
Implementation Method 1
a completely hydraulic actuation device comprising a cylinder group with an external 'controlled stroke' cylinder and an internal 'ON/OFF' cylinder
Data Source
Figure 1A~1C
Figure 2
Figure 4a~4b
AI summary
A device for adjusting the distance between a pair of work rollers (40) in an edger of a rolling mill comprising actuator means associable with a respective work roller (40). The actuator means comprise a roll group (10; 10s) including two cylinders (20, 20s; 30, 30s) associated with each other so to slide inside each other and movable between a withdrawn or maximum distance position between the rollers (40) and an advanced or minimum distance position between the rollers (40).