Rotational Force Transmission Assembly for Concentric Gear-Shaft Fitting
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Solution Overview
Problem
Existing rotational-force transmitting parts require tight fitting tolerances to achieve concentricity, leading to increased machining costs and complexity in assembly, while also being prone to eccentricity and backlash changes during rotation.
Innovation Solution
A rotational-force transmitting part design featuring a rotation support member with a cylindrical fitting surface, an annular elastic member such as an O-ring to maintain radial clearance, and a fixing member to secure the rotational-force transmitting member, allowing for center-alignment without excessive tolerance reduction, thus reducing machining costs and improving assembly ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tight fitting tolerances are used for the fitting portion between gear and shaft, then concentricity is improved, but machining cost increases and assembly complexity increases
Solution Approach 1:
An intermediary component (the fitting portion with specific tolerance design) is introduced between the gear and shaft to mediate their relationship. The fitting portion includes a shaft portion and hole portion with carefully designed tolerances that enable concentric assembly without requiring excessively tight tolerances on all surfaces, thus reducing machining costs while maintaining concentricity.
Solution Approach 2:
The tolerance parameters of the fitting portion are optimized to achieve the desired concentricity. By changing the tolerance values of the shaft portion and hole portion to appropriate ranges, the design achieves good concentricity without requiring extremely tight tolerances that would increase machining costs and assembly complexity.
2Manufacturing precision
If tight fitting tolerances are used for the fitting portion between gear and shaft, then concentricity is improved, but assembly complexity increases
Solution Approach 1:
The fitting portion serves as an intermediary that simplifies assembly. By designing the shaft portion and hole portion with appropriate tolerances and features, the assembly process becomes more straightforward compared to requiring tight tolerances on all mating surfaces, thus reducing assembly complexity while maintaining concentricity.
3Adaptability or versatility
If separate parts are used for gear and shaft, then functional optimization is improved, but concentricity control becomes more difficult
Solution Approach 1:
The fitting portion acts as an intermediary that enables separate manufacturing of gear and shaft for functional optimization, while simultaneously providing the mechanical connection needed for concentricity control. The shaft portion and hole portion with designed tolerances bridge the gap between separate components, allowing each to be optimized independently while maintaining precise relative positioning.
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 design achieves precise center-alignment of the shaft and gear, suppressing eccentricity and backlash changes, while allowing for the use of separate components optimized for their respective functions, thereby reducing material waste and assembly complexity.
Implementation Method 1
an annular elastic member that is disposed at such a position as to seal a space between the first fitting surface and the second fitting surface
Data Source
AI summary
Provided is a rotational-force transmitting part including: a rotation support member that is supported, with respect to a first member, so as to be rotatable about a predetermined axis by means of a bearing and that is provided with a first fitting surface formed of a cylindrical outer surface or a cylindrical inner surface centered on the axis; a rotational-force transmitting member that transmits a rotational force with respect to a second member and that is provided with a second fitting surface to be fitted onto the first fitting surface; an annular elastic member that is disposed at such a position as to seal a space between the first fitting surface and the second fitting surface; and a fixing member that fixes the rotational-force transmitting member and the rotation support member in a state in which the first fitting surface and the second fitting surface are fitted.