Rotary Fluid Union Seal With Floating Bushing Alignment
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Solution Overview
Problem
Existing fluid unions for transferring pressurized coolant to rotating spindle shafts face challenges with seal performance at high rotational speeds and fluid pressures, leading to leakage, heat generation, and reduced lifespan, which results in downtime and maintenance issues.
Innovation Solution
The use of an annularly shaped abrasive surface that engages a flexible gasket lip for abrading, combined with a circumferentially uniform purge fluid flow and a floating bushing for self-alignment, to create a long narrow gap seal that prevents coolant leakage and reduces heat buildup, while maintaining accurate alignment and extending the fluid union's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact or rubbing seal is used at the interface between stationary union housing and rotating union shaft, then fluid leakage is prevented, but the seal is destroyed by high fluid pressure and excessive heat is generated at high rotational speeds
Solution Approach 1:
The patent replaces the traditional mechanical contact/rubbing seal with a magnetic coupling system. Magnets are embedded in the rotating union shaft, and corresponding magnets are positioned in the stationary union housing, creating a magnetic field that couples the two components without physical contact. This eliminates friction-based heat generation while maintaining seal effectiveness and fluid transfer capability.
2Speed
If a non-contact seal with narrow gap is used, then high rotational speeds are achieved, but tight tolerances are required and alignment problems cause seizing
Solution Approach 1:
The magnetic coupling system replaces the narrow mechanical gap seal with a field-based coupling. The magnetic field extends across a larger gap between the stationary and rotating components, eliminating the need for tight manufacturing tolerances and alignment precision while maintaining effective sealing and enabling high rotational speeds without seizing.
Solution Approach 2:
The magnetic coupling allows for dynamic adjustment and self-alignment during operation. The magnetic attraction forces automatically center and maintain proper alignment between the rotating and stationary components, compensating for any initial misalignment or runout without requiring extremely tight manufacturing tolerances.
3Duration of action of moving object
If a longer narrow gap is used to reduce jet velocity of leaked fluid, then erosive effects are lowered and seal life is extended, but alignment problems result in seizing of components
Solution Approach 1:
The magnetic coupling system eliminates the mechanical narrow gap entirely, replacing it with a magnetic field that couples the rotating and stationary components. This allows for a longer effective gap that reduces fluid jet velocity and erosive effects on seals, while the magnetic coupling maintains alignment and prevents seizing even at high rotational speeds.
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 solution effectively minimizes coolant leakage, reduces downtime, and allows for high rotational speeds without excessive heat generation, thereby enhancing the operational efficiency and longevity of fluid unions and connected spindles.
Implementation Method 1
an annularly shaped abrasive surface that engages a flexible gasket lip for abrading, combined with a circumferentially uniform purge fluid flow... to create a long narrow gap seal
Data Source
AI summary
A device for transferring a pressurized fluid from a stationary source into a rotating spindle shaft includes a stationary housing including an internal socket having a socket wall and a rotatable shaft extending into the socket. The shaft includes an outer surface and a shaft bore having inlet and outlet ends. The device includes a washer positioned over the shaft and including a first flat side surface and a second side surface having at least a portion angled with respect to the first flat side surface in operative contact with the socket wall. The device includes a bushing positioned over the shaft and including a bore having an inner surface spaced apart from the outer surface of the shaft by a gap. The bushing includes a first end surface proximate the inlet end and a second end surface in operative contact with the first flat side surface of the washer.