Rolling Mill Cylinder Selection for Centered Bearing Bending Loads

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Solution Overview

Problem

Conventional rolling mills with multiple bending cylinders and complex control mechanisms require a large number of parts and increased complexity, leading to shorter bearing lifetimes due to offset loads, especially during large roll shifts.

Innovation Solution

A rolling mill design with a simplified structure featuring a controller-driven system that uses fewer bending cylinders to apply bending forces, allowing the resultant force to act on the bearing's central axis, reducing offset loads and eliminating the need for extensive mechanisms to adjust individual cylinder pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If multiple bending cylinders with adjustable pressures are used to reduce offset loads on bearings, then bearing lifetime is extended, but device complexity and number of parts increase significantly

Engineering Contradiction:
Improvebearing lifetimeVSAvoidnumber of bending cylinders and control mechanisms
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The bending force application is segmented into two distinct functional groups: first bending cylinders that apply bending force perpendicular to the rolling direction, and second bending cylinders that apply bending force in the rolling direction. This segmentation allows each group to be optimized for its specific function, reducing the need for complex individual pressure control on multiple cylinders while still achieving comprehensive bearing load management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second bending cylinders serve a dual function: they apply bending force in the rolling direction to counteract offset loads, and simultaneously constrain the position of the rolling rolls during shifting operations. This multi-functionality reduces the total number of cylinders needed compared to conventional systems that would require separate mechanisms for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Duration of action of stationary object

If individual cylinder pressure adjustment mechanisms are implemented to center the resultant bending force, then offset loads are reduced, but control complexity increases

Engineering Contradiction:
Improvebearing lifetimeVSAvoidcontrol complexity
Core Design Contradiction:
Duration of action of stationary objectVSEase of operation

Solution Approach 1:

The control system is segmented into two independent control groups corresponding to the two functional groups of bending cylinders. The controller independently manages first bending cylinders for perpendicular bending force and second bending cylinders for rolling direction bending force and roll position control. This segmentation simplifies control logic compared to managing individual pressure adjustment on multiple cylinders to achieve the same effect.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If the number of bending cylinders is reduced to simplify structure, then device complexity decreases, but the ability to control offset loads on bearings during large roll shifts deteriorates

Engineering Contradiction:
Improvenumber of bending cylindersVSAvoidoffset load control capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The second bending cylinders are designed to perform multiple functions: applying bending force in the rolling direction to counteract offset loads on bearings, and constraining the position of rolling rolls during shifting operations. This multi-functionality allows the system to maintain effective offset load control with fewer total cylinders compared to conventional systems where each function would require separate dedicated cylinders.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The bending cylinder system is designed to dynamically adapt to roll shift positions. The controller adjusts the bending force applied by the second bending cylinders based on the current roll position, enabling effective offset load control during large roll shifts without requiring a fixed large number of cylinders positioned to cover all possible shift ranges.

Inventive Principle:
Principle #15Dynamics

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 reduces offset loads on bearings, simplifies control and structure, and extends bearing lifespan by ensuring the bending force acts on the central axis, even during significant roll shifts, without the need for numerous mechanisms to adjust cylinder pressures.

Implementation Method 1

first bending cylinders that apply bending force vertically to the bearing 790 and that cause the roll to perform bending

Methodology Applied
Scientific EffectBending force: Mechanical Force

Implementation Method 2

second cylinders that apply pressing force to the bearing 790 in the rolling direction or in a direction opposite to the rolling direction

Methodology Applied
Scientific EffectPressing force: Mechanical Force

Data Source

PatentEP3812057B1Rolling mill and rolling method
Publication Date: 2023.01.04 PRIMETALS TECHNOLOGIES JAPAN LTD
  • EP3812057B1 patent drawingFigure 1
  • EP3812057B1 patent drawingFigure 2
  • EP3812057B1 patent drawingFigure 3

AI summary

To provide a rolling mill and a rolling method capable of reducing offset loads on bearings even with a simple structure as compared to conventional technologies. Two or more first cylinders 740, 741, 744, 745, are provided on each of the entry side and the exit side in the rolling direction, the two or more first cylinders being aligned in the axial direction, and a controller 80 is configured to be able to choose to drive one first cylinder on the entry side and one first cylinder on the exit side such that resultant force thereof acts on a central portion of a bearing when the roll performs bending and when at least the center of the bearing is arranged between the axially outermost first cylinder and the axially innermost first cylinder in the first cylinders.