Rotating Shaft Coupling Eliminating Run-Out via Interference Fit
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Solution Overview
Problem
Conventional propeller shaft couplings in vehicles often experience run-out issues due to non-axial connections, leading to imbalance and vibration, which are not fully addressed by existing flange mounting or spline connections that require radial clearance for assembly.
Innovation Solution
A rotary shaft coupling design featuring a male and female component with non-circular forms and a clamp nut that engages circular regions without radial clearance, providing an interference fit to eliminate run-out and ensure concentricity, using a circlip for retention and allowing for easy assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flange mounting is used for connection, then fixing axially and radially is achieved, but run-out at the coupling cannot be eliminated
Solution Approach 1:
The coupling is divided into distinct functional zones: a non-circular form section for torque transmission and circular form sections for precise axial alignment. This segmentation allows each zone to perform its specific function optimally without compromising the other.
Solution Approach 2:
The circular form sections act as intermediary elements between the non-circular torque-transmitting sections, providing a precise alignment interface that eliminates run-out while allowing the non-circular sections to handle torque transmission.
2Volume of moving object
If male/female spline connection is used, then radial size is reduced, but radial clearance is necessary for assembly which allows run-out possibility
Solution Approach 1:
The spline connection is segmented into a non-circular form section for torque transmission and circular form sections for alignment. This allows the compact spline structure to be combined with precise alignment features, eliminating run-out without increasing radial size.
Solution Approach 2:
Different sections of the coupling have different geometric qualities: non-circular sections provide torque transmission capability while circular sections provide precise alignment. This local differentiation allows each function to be optimized independently.
3Manufacturing precision
If collet-type clamp arrangement is provided to centralize the propeller shaft, then axial fixing is achieved, but assembly complexity increases
Solution Approach 1:
The centralization function is extracted from the torque transmission function by using separate circular form sections. This eliminates the need for complex collet-type arrangements, as the circular sections inherently provide precise alignment through their geometry.
Solution Approach 2:
The circular form sections self-align during assembly through their geometric properties, eliminating the need for additional centralizing mechanisms. The interference fit between circular sections automatically ensures precise alignment without requiring complex adjustment procedures.
4Manufacturing precision
If interference fit engagement of circular regions is implemented, then run-out is eliminated, but assembly force requirement increases
Solution Approach 1:
The coupling is segmented into multiple circular form sections that can be assembled sequentially. This distributes the assembly force requirement across multiple smaller engagement points rather than requiring one large interference fit, making assembly more manageable.
Data Source
AI summary
A rotary shaft coupling (10) for the drive-line of a vehicle includes a female component (11) of a propeller shaft (41) and a male component (12) of a drive axial pinion (42). The components have mutually engageable splines (14, 15) and circular regions (23, 25, 24, 26) drawn into engagement by a clamp nut (16) of the male component; the circular regions are a sliding or an interference fit. The clamp nut (16) may also be used to draw the components (11, 12) apart.