Self-Centering Flexible Shaft Coupling for Misalignment and Fatigue
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Solution Overview
Problem
Existing shaft coupling systems face challenges in accommodating axial movement and angular misalignment between movable parts, leading to stress concentrations and fatigue, particularly due to thermal expansion and misalignment during varying operational conditions.
Innovation Solution
A self-centering flexible coupling system that utilizes a spring biasing mechanism and interlocking splines to allow relative axial movement and misalignment, with the spring compressing to return the shafts to an equilibrium position, reducing wear and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rigid shaft coupling is used to maintain precise alignment, then alignment precision is improved, but the system cannot accommodate thermal expansion and misalignment, leading to stress concentrations and fatigue
Solution Approach 1:
The patent employs flexible splined couplings with diaphragms that can flex and deform to accommodate misalignment between shafts. The diaphragm acts as a flexible element that absorbs angular and axial misalignment while maintaining torque transmission, preventing stress concentrations that would occur with rigid couplings.
Solution Approach 2:
The patent uses biasing springs to actively adjust and maintain the equilibrium position of the shafts. The spring constant is selected to return the shafts to proper alignment when torque is below a predetermined value, dynamically adapting the coupling parameters based on operating conditions to prevent both excessive misalignment and stress.
2Adaptability or versatility
If a flexible coupling is used to accommodate misalignment, then adaptability is improved, but the coupling may wear from axial movement and angular misalignment
Solution Approach 1:
The flexible diaphragm coupling design allows controlled movement and deformation to accommodate misalignment while the biasing spring continuously pushes the splines to maintain optimal contact, reducing wear by preventing excessive play and impact loads during axial and angular movements.
Solution Approach 2:
The biasing spring provides self-centering action that automatically returns the shafts to equilibrium position after misalignment, and the spring constant is selected to provide sufficient force to maintain alignment without requiring external adjustment mechanisms, enabling the coupling to self-correct wear-prone conditions.
3Measurement precision
If a spring biasing mechanism is added to center the shafts, then alignment is improved, but device complexity increases
Solution Approach 1:
The patent integrates the biasing spring directly into the existing flexible coupling structure, combining the alignment function with the torque transmission and misalignment accommodation functions. The spring is positioned to act on the splined coupling elements, merging multiple functions into a single integrated component rather than adding separate alignment mechanisms.
Solution Approach 2:
The spring constant is carefully selected to provide sufficient biasing force for centering the shafts while remaining inactive or minimally active when torque exceeds the predetermined value, allowing the coupling to switch between spring-dominated alignment mode and torque-dominated engagement mode, simplifying the overall control strategy.
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 system effectively reduces wear and stress by automatically centering and aligning shafts, maintaining torque transmission while accommodating misalignment, and allowing for easy maintenance by replacing the spring if needed.
Implementation Method 1
the biasing means is arranged so as to compress in response to angular misalignment away from the equilibrium position between the first and second shaft axes and/or to compress in response to relative axial movement of the first and second shafts towards each other away from the equilibrium position
Data Source
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AI summary
A coupling (100) is described for allowing torque transmission between a first (12) and second shaft (14, 14a), the coupling (100) comprising: a cup-shaped portion (16) provided at a first end of said first shaft (12) and a first end (18) of said second shaft (14, 14a) being positioned within said cup-shaped portion (16); and said coupling (100) further comprising a biasing means (52) positioned between said first (12) and second shafts (14, 14a), such that said biasing means (52) is in contact with both of said first (12) and second shafts (14, 14a). A shaft system is also described comprising this first coupling (100) in combination with a third shaft (14b) and a second coupling (100a) that is provided between the third shaft (14b) and either a second end of said first shaft (12) or a second end of said second shaft (14, 14a). The second coupling (100a, 100b) is identical to the first coupling (100). A method of coupling these shafts together is also described.