Hexagonal Male and Twisted Triangular Female Rotating Part
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Solution Overview
Problem
The existing rotating parts in image forming apparatuses face challenges with complex and large molding dies for twisted columnar protrusions, leading to difficulties in smooth disengagement and transmission of rotational force, which can result in deformation and inaccuracies during the loading and unloading of photosensitive drums.
Innovation Solution
A rotating part design featuring a hexagonal male part and a twisted triangular female part, where the hexagonal male part is inserted into the twisted triangular female part, preventing deformation and ensuring smooth engagement and disengagement, and maintaining accurate transmission of rotational force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a twisted columnar protrusion is formed by injection molding, then rotation can be transmitted, but the molding die becomes structurally complicated and large
Solution Approach 1:
The engagement interface is segmented into a male part with a columnar protrusion and a female part with a corresponding hole, allowing simpler molding dies to produce the components separately rather than requiring a complex single-piece twisted structure
Solution Approach 2:
Instead of forming the twisted shape directly in the protrusion (male part), the twist is applied to the hole (female part), inverting which component carries the complex geometry. This allows the male part to be molded with a simpler die while the female part receives the twisted configuration
2Power
If a twisted columnar protrusion is used, then power transmission is achieved, but smooth disengagement becomes difficult
Solution Approach 1:
The engagement interface is designed to be dynamically adjustable, allowing the male and female parts to self-align during engagement and disengagement. The tapered surfaces enable the components to slide smoothly into and out of engagement without requiring forced rotation or complex manipulation
3Ease of manufacture
If a simple columnar protrusion is used, then manufacturing is easier, but transmission accuracy of rotation deteriorates
Solution Approach 1:
The engagement interface uses asymmetric polygonal cross-sections (triangle, quadrangle, pentagon, or hexagon) instead of simple circular columns. This asymmetric geometry prevents relative rotation between the male and female parts, ensuring accurate power transmission while still allowing the components to be molded separately with relatively simple dies
4Device complexity
If the contact area between hole and shaft bearing part is reduced, then the structure becomes simpler, but force concentration causes flaws or dents
Solution Approach 1:
The tapered surfaces on the male and female parts create a preliminary guiding action during engagement, distributing the insertion force gradually along the tapered surfaces rather than concentrating it at a single point. This preliminary action prevents flaws or dents while maintaining structural simplicity
Data Source
AI summary
A rotating part for an image forming apparatus includes a drive member for transmitting power; and a driven member that is rotated by the drive member. The drive member has a male part formed in a direction of a rotation axis, and the driven member has a female part that is formed in the direction of the rotation axis and into which the male part is inserted. The male part is a hexagonal male part whose cross section perpendicular to the rotation axis assumes a hexagonal shape. The female part is a twisted triangular female part that assumes a triangular cross sectional profile in a direction perpendicular to the rotation axis, and a triangle which forms a cross section of a base and a cross section of a top is twisted at a predetermined angle with respect to the rotation axis.