Roller Bearing Inner Ring Cutouts for Scratch-Free Assembly
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Solution Overview
Problem
The assembly process of roller bearing assemblies, particularly in gas turbine engines, often results in damage to components due to tight fits that can cause scratching of bearing elements as they engage with the outer ring, and traditional measures like large lead-in chamfers and positive radial clearance may not be sufficient to prevent such damage.
Innovation Solution
A roller bearing assembly design featuring an outer ring with an extended width and an inner ring with cutout portions on its circumferential surface, allowing for a clearance between the cutout and the shaft, and a method for installing the inner ring after the roller bearing elements engage with the outer ring, which minimizes the risk of scratching by ensuring the inner ring only engages the shaft after the elements are securely positioned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner ring is installed on the shaft with a tight fit, then the bearing assembly achieves secure mounting, but the radial clearance is reduced causing bearing elements to be scratched during engagement with the outer ring
Solution Approach 1:
The inner ring's circumferential surface is segmented into a base portion and at least one cutout portion. This segmentation allows the bearing assembly to engage the shaft in two distinct phases: first the roller bearing elements engage the outer ring, then the base portion engages the shaft. This resolves the contradiction by preventing scratching during the first phase while ensuring secure mounting in the second phase.
Solution Approach 2:
The design enables preliminary engagement of the roller bearing elements with the outer ring before the inner ring contacts the shaft. The cutout portions are specifically designed to delay shaft contact, allowing the bearing elements to be securely positioned first. This preliminary action prevents scratching while maintaining mounting security.
2Object-affected harmful factors
If traditional measures like large lead-in chamfers and positive radial clearance are used, then scratching is partially prevented, but the measures are insufficient to fully prevent damage during assembly
Solution Approach 1:
Instead of relying solely on chamfers and clearance, the invention segments the inner ring surface into base and cutout portions. This creates a mechanical sequence where bearing elements engage first, then the shaft engages. This segmentation provides superior protection against scratching compared to traditional chamfer approaches.
Solution Approach 2:
The cutout portions enable preliminary engagement of bearing elements with the outer ring before shaft contact occurs. This timing control ensures bearing elements are securely positioned and protected before any contact with the shaft, providing more reliable damage prevention than traditional measures.
3Ease of operation
If the inner ring width is made lesser than the outer ring width, then the axial extension is created for smoother engagement, but the structural complexity increases
Solution Approach 1:
The inner ring width is reduced relative to the outer ring, creating an axial extension. The inner circumferential surface is segmented into base and cutout portions. This segmentation, combined with the width difference, creates a controlled engagement sequence that smooths the assembly process while the complexity is managed through the functional design of the cutout portions.
Data Source
AI summary
An inner ring cooperates with an outer ring to form a roller bearing assembly. The inner ring comprises an outer circumferential surface receiving a plurality of roller bearing elements engageable with the outer ring upon forming of the roller bearing assembly. An inner circumferential surface of the inner ring is slideably mountable to a shaft upon forming of the roller bearing assembly and includes a base portion slideably engageable with a surface of the shaft upon mounting and at least one cutout portion opening to an outer edge of the inner circumferential surface. A clearance forms between a surface of the at least one cutout portion and the surface of the shaft upon mounting. Upon forming of the roller bearing assembly, the base portion of the circumferential surface is engageable with the shaft subsequently to the plurality of roller bearing elements engaging with the outer ring.