Roller Mechanism Sleeve Engagement for Rotational Stability
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Solution Overview
Problem
Existing image forming apparatuses face issues with rotational slippage and instability due to clearance fitting between rotation shafts and bearings, leading to reduced durability and maintainability, especially during acceleration, deceleration, and direction changes.
Innovation Solution
A support member system that includes a sleeve fixed to the inner ring of a bearing, which is clearance-fitted with the rotation shaft and engaged in a specific direction, using commercially available standard bearings without additional machining, preventing rotational slippage and allowing easy assembly and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If clearance fitting is used between the rotation shaft and the inner ring of the bearing, then ease of assembly and replacement is improved, but rotational slippage and shaft scraping occur leading to reduced reliability
Solution Approach 1:
A groove is formed in the inner ring of the bearing and a protrusion is formed on the rotation shaft to create an engagement structure that prevents rotational slippage. This intermediary geometric feature acts as a mediator between the clearance fit (which enables easy assembly) and the need for rotational stability, allowing both requirements to be satisfied simultaneously.
2Ease of repair
If clearance fitting is used between the rotation shaft and the inner ring of the bearing, then ease of replacement during maintenance is improved, but durability is reduced due to shaft scraping
Solution Approach 1:
The groove-protrusion engagement structure serves as an intermediary feature that prevents direct contact and scraping between the rotation shaft and inner ring during normal operation. This maintains durability while preserving the clearance fit that enables easy replacement during maintenance.
3Reliability
If a non-circular bearing is used to prevent rotational slippage, then rotational stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
Instead of changing the entire bearing to a non-circular shape (which would increase complexity), the groove is formed only in the specific local region of the inner ring where engagement with the rotation shaft protrusion is needed. This local modification maintains the overall simplicity of the bearing while achieving the goal of preventing rotational slippage.
4Reliability
If dedicated machined components are used to prevent rotational slippage, then rotational stability is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The groove is formed locally in the inner ring at the specific position where engagement is needed, rather than requiring comprehensive machining of entire dedicated components. This local modification approach reduces manufacturing cost and complexity while effectively preventing rotational slippage between the rotation shaft and bearing.
Data Source
AI summary
A roller mechanism includes a roller and a support member that supports the rotation shaft. Herein, the support member includes a bearing having an outer ring and inner ring which rotate relatively to each other, and a sleeve that is fittingly fixed to the inner ring, wherein the sleeve and rotation shaft are fitted to each other by clearance fitting and further engaged with each other with respect to a rotation direction.