Split Inner Ring Spherical Bearing Axial Clearance Reduction

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Solution Overview

Problem

Spherical bearings with split inner rings require significant axial clearance for assembly, leading to increased wear, lubricant loss, and reduced lifespan due to single-point contact and large axial clearance.

Innovation Solution

The design features an outer ring with a concave arcuate bearing surface and an inner ring with a convex arcuate surface, where the inner ring is split into sections to reduce axial clearance by radially displacing the surfaces, allowing for two-point contact and a crescent-shaped void to retain lubricant, thereby minimizing wear and stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the inner ring is split into sections to facilitate replacement, then ease of assembly is improved, but axial clearance increases leading to wear and lubricant loss

Engineering Contradiction:
Improveease of assemblyVSAvoidbearing lifespan
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The inner ring is divided into two separable halves that can be independently inserted through the outer ring's opening. This segmentation enables assembly without requiring the inner ring to pass through the entire outer ring, thus facilitating maintenance while controlling clearance through precise geometric design of the bearing surfaces.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If sufficient clearance is provided between bearing surfaces for assembly, then ease of assembly is improved, but axial clearance increases causing lubricant egress and foreign object intrusion

Engineering Contradiction:
Improveease of assemblyVSAvoidforeign object intrusion and lubricant loss
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the geometric parameters of the bearing surfaces by applying specific radius of curvature relationships. The concave surface radius RO and convex surface radius RI are designed to satisfy RO < RI + A, where A is the radial displacement. This parameter optimization enables adequate assembly clearance while minimizing axial clearance to prevent harmful effects.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the bearing surfaces are designed for single-point contact, then manufacturing is simplified, but stress concentration increases decreasing bearing lifespan

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidbearing stress distribution
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent employs curved bearing surfaces with specifically related radii of curvature. The concave arcuate surface and convex arcuate surface are designed with radii RO and RI respectively, where RO < RI + A. This curvature relationship transforms single-point contact into multi-point contact, distributing stress across a larger area while maintaining manufacturability through standard spherical geometry.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2981724B1Spherical bearing and method of making the same
Publication Date: 2018.05.30 SCHAUBLIN
  • EP2981724B1 patent drawingFigure 1~2
  • EP2981724B1 patent drawingFigure 3~4
  • EP2981724B1 patent drawingFigure 5A~5C

AI summary

A bearing having an outer ring defining a concave arcuate bearing surface having a radius of curvature Ro in an axial cross section of the bearing. The bearing has an inner ring defining a convex arcuate bearing surface having a radius of curvature R1 in the axial cross section of the bearing. The inner ring is rotatable relative to the outer ring about a first axis of rotation and the inner ring is angularly displaceable relative to the outer ring when the inner ring is disposed in the outer ring. The concave arcuate bearing surface is radially displaced from the convex arcuate bearing surface by a distance A at an axial center of the bearing when the inner ring is concentric with the outer ring. Ro is less than the sum of R1 and A.