Cylindrical Roller Bearing Rib Geometry for Abrasion Resistance

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Solution Overview

Problem

Cylindrical roller bearings in continuous-casting machines experience abrasion and scuffing issues due to insufficient lubrication, particularly at the rib surfaces, which are prone to damage under high loads and low-speed conditions, leading to reduced durability and increased maintenance costs.

Innovation Solution

The cylindrical roller bearing design features convex spherical end surfaces for the rollers and ribs, with contact points set to achieve point-contact elliptical surfaces, reducing sliding speed and surface pressure, thereby minimizing abrasion and scuffing. This design includes a full complement configuration without a retainer, with specific rib and roller arrangements to distribute axial loads effectively and reduce tilting, enhancing stability and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat rib surface is used to support axial load, then the structure is simple and easy to manufacture, but insufficient lubrication occurs under high load and low speed, leading to abrasion and scuffing

Engineering Contradiction:
Improverib structure simplicityVSAvoidresistance to abrasion and scuffing
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention replaces the flat rib surface with a convex spherical surface. This curvature transformation changes the contact from surface-to-surface to point contact, significantly reducing the contact area and improving lubrication conditions. The spherical shape maintains manufacturing feasibility while effectively preventing abrasion and scuffing under high load and low speed conditions.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If cylindrical rollers with flat end surfaces are used, then the roller manufacturing is simple, but surface contact with the rib causes prominent insufficient lubrication and bearing damage

Engineering Contradiction:
Improveroller manufacturing simplicityVSAvoidbearing durability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention modifies the roller end surfaces from flat to convex spherical shapes. This curvature change transforms the contact mode from surface contact to point contact with the rib, dramatically reducing the contact area and improving lubrication effectiveness. The spherical end surfaces maintain relatively simple manufacturing processes while significantly enhancing bearing durability by preventing insufficient lubrication damage.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If point contact is achieved between roller end and rib, then sliding speed is reduced and lubrication is improved, but the contact area is smaller leading to higher surface pressure

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidsurface pressure at contact point
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The invention optimizes the curvature radius parameter of the spherical rib surface and roller end surfaces. By carefully selecting the curvature radius within a specific range (0.05-0.2 times the roller diameter), the design balances point contact benefits (reduced sliding speed, improved lubrication) with acceptable surface pressure levels. This parameter optimization ensures that while contact area is reduced to improve lubrication, the surface pressure remains within acceptable limits for the bearing materials.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively suppresses abrasion and scuffing of rib surfaces and rollers, improving the bearing's durability and extending its replacement cycle, thus reducing maintenance costs and ensuring stable operation under varying thermal conditions.

Implementation Method 1

contact states denoted by the term 'point-contact' include a contact state where an elliptical contact surface is formed if a load is applied in the direction perpendicular to a contact surface

Methodology Applied
Scientific EffectPoint-contact: Friction

Data Source

PatentEP2202417B1Roller bearing
Publication Date: 2011.04.13 JTEKT CORP
  • EP2202417B1 patent drawingFigure 1
  • EP2202417B1 patent drawingFigure 2
  • EP2202417B1 patent drawingFigure 3

AI summary

A roller bearing (5) includes: an outer ring (13) that has outer ring raceway surfaces (13b1, 13b2); an inner ring (12) that has inner ring raceway surfaces (12b1, 12b2) that face the outer ring raceway surfaces (13b); a plurality of cylindrical rollers (141, 142) that are arranged between the outer ring raceway surfaces (13b) and the inner ring raceway surfaces (12b). The outer ring (13) has an outer ring rib (13a) that is in point-contact with one axial end surface of each of the cylindrical rollers (141, 142) and that is arranged adjacent to the outer ring raceway surfaces (13b). Contact positions (Po) at which the cylindrical rollers (141, 142) contact the outer ring rib (13a) are set to be on an axis (O1) of the cylindrical roller (141) and an axis (02) of the cylindrical roller (142).