Segmented Spherical Oil Film Bearing for Shorter Mill Assembly

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Solution Overview

Problem

Spherical oil film bearings for rolling mills face challenges such as difficult assembly and maintenance due to discontinuous internal surfaces, inadequate lubrication, and excessive length, which have hindered their adoption in heavily loaded applications despite their potential to simplify mill design and increase stiffness.

Innovation Solution

A novel spherical oil film bearing design featuring a subdivided bushing with interconnected segments and a continuous internal spherical surface, along with a lubrication system using elliptically rebored pads to ensure effective lubrication, addresses these issues by allowing for easier assembly, improved alignment, and reduced length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the bushing is subdivided into multiple separate components, then assembly is simplified, but alignment difficulty increases and manufacturing complexity worsens

Engineering Contradiction:
Improveassembly easeVSAvoidalignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The bushing is divided into multiple separate components (first bushing component, second bushing component, etc.) that can be assembled independently around the sleeve. This segmentation allows each component to be manufactured and prepared separately, improving ease of assembly while maintaining the ability to achieve proper alignment through the connection elements provided in the patent.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the internal spherical surface is made continuous, then lubrication improves, but manufacturing complexity increases

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent provides for a continuous internal spherical surface in the bushing that extends across all bushing components. This continuous surface ensures uniform lubrication distribution and consistent contact with the spherical sleeve, improving reliability by eliminating discontinuities that would disrupt the lubrication film and bearing performance.

Inventive Principle:
Principle #12Equipotentiality

3Length of stationary object

If the bearing length is reduced, then mill stiffness increases, but lubrication adequacy worsens

Engineering Contradiction:
Improvebearing lengthVSAvoidlubrication adequacy
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent employs elliptically rebored pads located at specific positions within the bushing components. These rebored pads create localized regions with enhanced lubrication capacity and oil retention, ensuring adequate lubrication is maintained even when the overall bearing length is reduced. The local quality enhancement at critical locations compensates for the reduced overall length.

Inventive Principle:
Principle #3Local quality

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 improved design enhances the assembly and maintenance of spherical oil film bearings, ensures adequate lubrication, and shortens the bearing length, thereby increasing the stiffness and operational efficiency of rolling mills.

Implementation Method 1

A means is provided for supplying liquid lubricant to the interface between the external and internal spherical bearing surfaces

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3265250B1Spherical oil film bearing
Publication Date: 2021.01.20 PRIMETALS TECHNOLOGIES USA LLC
  • EP3265250B1 patent drawingFigure 1
  • EP3265250B1 patent drawingFigure 2
  • EP3265250B1 patent drawingFigure 3~4

AI summary

An oil film bearing rotatably supports a roll in a rolling mill. The bearing comprises a sleeve 28 having an internal bore 30 and an external spherical surface 32. The internal bore is configured and dimensioned for axial insertion onto a neck 34 of the roll. A bushing 38 has an internal spherical surface configured and dimensioned to surround and rotatably contain the external spherical surface of the sleeve. The bushing is subdivided into multiple interconnected segments 38a, 38b contained and radially supported by a chock 46.