Self-aligning Roller Bearing Rib Clearance Design

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Solution Overview

Problem

Conventional self-aligning roller bearings experience wear issues due to skewed spherical rollers contacting the guide ring, leading to potential service life reduction and debris-related problems.

Innovation Solution

The self-aligning roller bearing design incorporates specific clearance relationships between spherical rollers, rib portions, and a guide ring, where the clearance between the spherical rollers and the rib portions is smaller than that between the rollers and the guide ring, reducing the likelihood of contact with the guide ring, which is made of a softer material than the rollers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If spherical rollers are allowed to rotate about virtual lines passing through contact points with outer raceway surface and inner raceway surfaces, then self-aligning function is achieved, but spherical rollers become skewed and contact the guide ring causing wear

Engineering Contradiction:
Improveself-aligning functionVSAvoidguide ring wear
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces rib portions as intermediary elements between the spherical rollers and the guide ring. These rib portions act as a mediator that receives the contact force from skewed spherical rollers, preventing direct contact between the rollers and the guide ring. The rib portions are positioned to intercept the skewed rollers before they can reach the guide ring, thereby eliminating the wear problem while preserving the self-aligning function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of spherical roller skewing into a beneficial outcome. Instead of allowing skewed rollers to contact and wear the guide ring, the design directs the skewed rollers to contact the rib portions. The skewing phenomenon, which was previously harmful, is now utilized to ensure contact with the rib portions that protect the guide ring, effectively converting the harmful skewing motion into a protective mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Strength

If guide ring is made of softer material than spherical rollers, then cushioning effect is provided, but guide ring wears due to contact with skewed spherical rollers

Engineering Contradiction:
Improvecushioning effectVSAvoidguide ring service life
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent extracts the function of receiving roller contact forces from the guide ring and relocates it to the rib portions. By removing the direct contact relationship between spherical rollers and guide ring, the guide ring is no longer subjected to wear-causing contact forces. The rib portions assume the role of absorbing and distributing the contact forces, allowing the guide ring to maintain its cushioning function without experiencing wear.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If clearance between spherical rollers and guide ring is reduced, then contact is prevented, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecontact preventionVSAvoidclearance control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The rib portions serve as intermediary elements that create a controlled clearance zone between the spherical rollers and the guide ring. By positioning the rib portions at specific locations, the patent establishes a predetermined clearance that is sufficient to prevent contact between skewed rollers and the guide ring. This intermediary structure allows for reasonable manufacturing tolerances while ensuring reliable contact prevention.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3385552B1Self-aligning roller bearing
Publication Date: 2020.02.26 JTEKT CORP
  • EP3385552B1 patent drawingFigure 1
  • EP3385552B1 patent drawingFigure 2
  • EP3385552B1 patent drawingFigure 3

AI summary

In a self-aligning roller bearing, in a longitudinal section including a center line of a spherical roller and an axis of the self-aligning roller bearing, a clearance X between an outer end surface of a spherical roller on an axially outer side of the self-aligning roller bearing and a rib portion, and a clearance Y between an inner end surface of the spherical roller on an axially inner side of the self-aligning roller bearing and a guide ring have a relation of X < Y.