Hydraulic Orifice and Chamber Design for Rolling Mill Vibration Control
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Solution Overview
Problem
Conventional methods for controlling mill vibration in hot rolling mills rely on reducing the orifice diameter of hydraulic supply-discharge pipes, which can lead to dust clogging and inadequate vibration control due to limitations in achieving designed cylinder operation speeds.
Innovation Solution
The implementation of a rolling mill design that includes a flow contracting unit and an expanding unit in the hydraulic supply-discharge pipe, with the flow contracting unit positioned closer to the hydraulic pressing means and an orifice diameter set to φ2.5 mm or above, along with a chamber volume that enhances dynamic stiffness by varying the damping ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the orifice diameter is reduced to improve static stiffness, then vibration control is enhanced, but dust clogging occurs and cylinder operation speed decreases
Solution Approach 1:
The patent applies dynamics by introducing a chamber that allows the hydraulic oil to expand and contract, transforming the static stiffness improvement approach into a dynamic vibration control mechanism. The chamber volume (7%-180% of hydraulic pressing means volume) creates a dynamic response that enhances damping ratio without restricting oil flow through a small orifice, thereby maintaining cylinder operation speed while controlling vibration.
Solution Approach 2:
The patent changes the parameter of orifice diameter from the conventional small size (φ2.0 mm or below) to a larger size (φ2.5 mm or above), which prevents dust clogging and maintains oil flow speed. The vibration control is achieved not through orifice size reduction but through the addition of a chamber that modifies the hydraulic system's dynamic characteristics, specifically the damping ratio.
2Stability of the object's composition
If the orifice diameter is reduced excessively to improve vibration control, then static stiffness increases, but the system becomes unreliable due to dust clogging
Solution Approach 1:
The chamber acts as an intermediary element between the hydraulic pressing means and the hydraulic supply-discharge pipe. Instead of relying on a small orifice to control vibration, the chamber provides a intermediate space that allows the hydraulic oil to expand and contract, thereby controlling vibration through pressure changes rather than flow restriction, which eliminates dust clogging issues.
3Stability of the object's composition
If the orifice diameter is reduced to control mill vibration, then static stiffness is improved, but dynamic stiffness and damping ratio are insufficient
Solution Approach 1:
The patent transitions from a static stiffness-based vibration control approach to a dynamic approach by incorporating a chamber that responds to pressure changes during operation. The chamber volume (7%-180% of hydraulic pressing means volume) creates a dynamic damping effect that enhances dynamic stiffness, making the system more effective at controlling mill vibration during actual rolling operations.
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 configuration effectively controls mill vibration without excessively reducing the orifice diameter, improving dynamic stiffness and reducing the likelihood of dust clogging, while maintaining smooth oil flow and operational efficiency.
Implementation Method 1
a flow contracting unit and an expanding unit are provided to a portion of a hydraulic supply-discharge pipe on a head side of the hydraulic pressing means
Implementation Method 2
a flow contracting unit and an expanding unit are provided to a portion of a hydraulic supply-discharge pipe on a head side of the hydraulic pressing means
Implementation Method 3
a pair of upper and lower first supporting means provided to the housing at positions on one side in a rolling direction for supporting the pair of upper and lower work roll chocks; and a pair of upper and lower second supporting means provided to the housing at positions on another side in the rolling direction for supporting the pair of upper and lower work roll chocks, wherein the first supporting means is used as hydraulic pressing means and is made capable of pressing the pair of upper and lower work roll chocks in a horizontal direction
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(c)
Figure 3(a)~3(c)
AI summary
In the rolling mill, an orifice (20) (contracted flow part) and a chamber (21) (expanded part) are provided in a hydraulic line (19) for a hydraulic cylinder (17) (hydraulic pressing means). The orifice (20) is disposed more to the hydraulic cylinder (17) side than the chamber (21). The internal diameter of the orifice (20) is set to be 2.5 mm (ϕ) or greater and 15 - 85% of the internal diameter of the hydraulic line (19). Thus, it is possible to control milling vibration.