Frustoconical Input Shaft for Torque and Misalignment Balance
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Solution Overview
Problem
Propulsion systems with speed reduction mechanisms face challenges in mechanical strength and flexibility due to misalignment issues, leading to reduced service life from concentrated static and dynamic loads, particularly at the junction of the shaft and gussets.
Innovation Solution
A shaft with a frustoconical barrel and symmetrical gussets is designed to decouple the concentration of static and dynamic loads, where the barrel's frustoconical shape and gusset dimensions optimize mechanical strength and flexibility, with the barrel being stiffer near the gusset connected to the bearing and more flexible near the sun gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid barrel and straight gussets are used in the shaft, then torque transmission is improved, but misalignment compensation capability deteriorates
Solution Approach 1:
The shaft employs different geometric properties in different regions: the barrel is frustoconical with varying diameter along its length, providing different stiffness characteristics at different locations. The gussets have optimized dimensions and positions to provide flexibility where needed while maintaining strength where required. This local differentiation allows simultaneous achievement of torque transmission and misalignment compensation.
2Adaptability or versatility
If the shaft is made more flexible to compensate misalignments, then misalignment tolerance is improved, but mechanical strength under static loads deteriorates
Solution Approach 1:
The shaft design utilizes parameter optimization including the frustoconical barrel geometry with specific diameter ratios, gusset thickness and positioning parameters, and material properties to achieve the desired balance between flexibility and strength. The geometric parameters are carefully selected to provide adequate misalignment tolerance while maintaining structural integrity under static loading conditions.
3Strength
If the shaft geometry is optimized for strength, then mechanical robustness is improved, but flexibility to accommodate misalignments deteriorates
Solution Approach 1:
The shaft is segmented into distinct functional zones: the frustoconical barrel section provides progressive stiffness transition, while the gusset regions provide localized flexibility. This segmentation allows each zone to perform its specific function optimally - the barrel for strength and the gussets for flexibility - thereby resolving the contradiction between mechanical robustness and adaptability.
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
This design significantly enhances the service life margin of the shaft by distributing loads effectively, improving mechanical robustness and flexibility while maintaining the shaft's geometric and inertial properties.
Implementation Method 1
the barrel being stiffer near the gusset connected to the bearing and more flexible near the sun gear
Implementation Method 2
the barrel's frustoconical shape and gusset dimensions optimize mechanical strength and flexibility
Data Source
AI summary
The present invention relates to a shaft for a propulsion system configured to rotate a reducing mechanism about a rotational axis, the shaft comprising: —a first end configured to engage with an input gear of the reducing mechanism, —a first bellows and a second bellows, the first bellows and the second bellows being rotationally symmetrical about the rotational axis, the first bellows extending between the first end and the second bellows, and —a frustoconical body mechanically connecting the first bellows and the second bellows.