Overshaft Fluid Coupling Assembly for Radial Runout Sealing
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Solution Overview
Problem
In machines with rotating hollow shafts, fluid transfer through the radial wall is challenging due to spatial constraints and requires a reliable sealing mechanism that maintains fluid communication while accommodating radial movements and manufacturing runouts.
Innovation Solution
A fluid transfer coupling arrangement using a sleeve with locating features, such as a tab and slot configuration, and sealing surfaces with grooves, which allows radial movement and maintains sealing engagement with the hollow shaft, and includes a transfer tube system for fluid communication, ensuring uniform gap and desired sealing engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fluid coupling is arranged over the shaft with close tolerance lands to provide fluid transfer path, then fluid transfer efficiency is improved, but the coupling becomes sensitive to radial movements and manufacturing runouts
Solution Approach 1:
The patent employs dynamic clearance adjustment mechanisms that allow the sealing surfaces to maintain optimal contact under varying radial conditions. The coupling design incorporates flexible sealing elements and compensating features that adapt to radial movements and runouts, ensuring consistent sealing performance while maintaining fluid transfer efficiency.
Solution Approach 2:
The invention utilizes controlled clearance variations and pressure differential adjustments to maintain reliable sealing. By dynamically adjusting the gap between sealing surfaces and utilizing pressure gradients, the system compensates for manufacturing tolerances and radial displacements, preserving both fluid transfer efficiency and sealing integrity.
2Strength
If a bolted flange joint is used to fasten the fluid coupling to the housing, then the coupling is securely fixed, but assembly complexity and time increase
Solution Approach 1:
The coupling assembly is divided into modular components that can be pre-assembled and tested separately, then quickly installed as a unit. This segmentation allows for simplified attachment mechanisms while maintaining secure fixation, reducing overall assembly time without compromising structural integrity.
Solution Approach 2:
Critical sealing and alignment features are pre-configured during manufacturing or preliminary assembly steps. Locating features and sealing surfaces are precisely prepared in advance, enabling rapid final assembly with reduced need for on-site adjustment and alignment work.
3Manufacturing precision
If close tolerance lands are used to create annular transfer paths, then fluid coupling precision is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
Instead of requiring close tolerances across the entire coupling surface, the invention applies precision machining only to specific critical landing zones where fluid transfer occurs. Non-critical areas use standard tolerances, significantly reducing manufacturing complexity and cost while maintaining fluid coupling precision in the functional regions.
Solution Approach 2:
The design incorporates slightly larger clearances in non-critical areas and uses flow distribution mechanisms to concentrate fluid transfer through the precisely machined regions. This partial precision approach achieves the required fluid coupling accuracy without the expense of machining the entire coupling to tight tolerances.
Data Source
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AI summary
In one example embodiment, a fluid transfer coupling arrangement includes a hollow shaft, 50, that is arranged in a housing, 40, and rotatable about an axis. The hollow shaft is provided by a wall, 58, having radially spaced interior, 60, and exterior surfaces, 62. A first passage extends through the wall and is configured to communicate fluid between the interior and exterior surfaces. A fluid coupling is located mid-shaft, sealed about the exterior surface, and aligns to the first passage. The fluid coupling provides a second passage that is in fluid communication with the first passage. The fluid coupling includes a locating feature configured to permit radial movement of the fluid coupling, 46, relative to the housing, 40, and allowing the fluid coupling to track subtle shaft movements.