Snap Ring Geometry for Tool-Free Fixing Roller Shaft Retention
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Solution Overview
Problem
Existing snap rings for fixing rollers in image forming apparatuses are difficult to set and remove due to high elastic deformation restoring forces, requiring specialized tools and potentially causing damage to the rollers, and may not provide a clear indication of correct fitting, leading to setting failures.
Innovation Solution
A snap ring design featuring a first and second arcuate portion with equal radii of curvature, where the center of curvature of one portion is closer to the other, allowing for easy elastic deformation and setting without specialized tools, and including guides and a handling projection for smooth attachment and detachment, reducing the risk of damage and ensuring correct fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the snap ring has high elastic deformation restoring force to hold the shaft securely, then the holding reliability is improved, but the ease of operation for setting and removing the snap ring deteriorates
Solution Approach 1:
The snap ring is divided into two arcuate portions with different center of curvature positions. The first arcuate portion has its center of curvature closer to the second arcuate portion, creating asymmetric elastic deformation characteristics. This segmentation allows one portion to provide strong holding force while the other facilitates easier insertion and removal operations.
Solution Approach 2:
The asymmetric positioning of centers of curvature creates unequal elastic deformation restoring forces in the two arcuate portions. The first arcuate portion with center closer to the second provides stronger holding force, while the configuration as a whole enables easier operation during setting and removing compared to symmetric designs.
2Force
If the snap ring requires specialized tools for setting and removing, then the holding force is improved, but the device complexity increases
Solution Approach 1:
The asymmetric arcuate portion design enables the snap ring to be set and removed by hand or with simple tools. The elastic deformation characteristics of the first arcuate portion (with center closer to the second) naturally facilitate insertion and removal operations, eliminating the need for specialized complex tools while maintaining strong holding force.
3Reliability
If the snap ring has strong elastic deformation restoring force, then the holding reliability is improved, but the risk of damage to the roller increases
Solution Approach 1:
The first arcuate portion is designed with its center of curvature closer to the second arcuate portion, creating localized elastic deformation characteristics. This local quality difference allows the snap ring to apply holding force effectively while distributing stress in a manner that reduces the risk of damage to the roller shaft during setting and removal operations.
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 snap ring design facilitates easy and secure attachment and detachment from the fixing roller shaft, preventing damage and ensuring accurate fitting, while maintaining sufficient holding force to restrict axial displacement under thrust loads.
Implementation Method 1
A part of the snap ring is removed in a circumferential direction of the snap ring to form an insertion portion into which a set portion of a shaft of a rotator is inserted in a direction orthogonal to an axial direction of the shaft. Inserting the set portion into the insertion portion elastically deforms the first arcuate portion and the second arcuate portion and opens the insertion portion.
Implementation Method 2
The inserted set portion is sandwiched by the first arcuate portion and the second arcuate portion. Elastic deformation restoring forces of the first arcuate portion and the second arcuate portion holds the shaft.
Data Source
AI summary
A snap ring is set to a set portion of a shaft of a rotator from a direction orthogonal to an axial direction of the shaft. The snap ring includes a first arcuate portion and a second arcuate portion facing each other, being elastically deformable in directions away from each other, holding the set portion by elastic deformation restoring force. One ends of the first and second arcuate portions are away from each other to form an insertion portion to insert the set portion. When the snap ring is not used, the first arcuate portion has a same radius of curvature as the second arcuate portion and the set portion, and a center of curvature closer to the second arcuate portion than the first arcuate portion, and the second arcuate portion has a center of curvature closer to the first arcuate portion than the second arcuate portion.