Static Conduit Hydraulic Coupling for Propeller Drive
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Solution Overview
Problem
Contra-rotating propeller engines face challenges with high maintenance burdens and reduced slip ring life due to high operating speeds, and existing solutions like rotating hydraulic couplings face design constraints and issues with gear assembly stiffness and blade feathering capabilities.
Innovation Solution
An engine arrangement featuring a static conduit within a power drive shaft that houses hydraulic rotating couplings, allowing for low PV value and low leakage hydraulic power transfer to hydraulic actuators, avoiding the need for large diameter couplings and reducing the impact on gear assembly stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If slip rings are used to transfer power from static to rotating field, then power transfer is achieved, but maintenance burden increases and component life reduces due to high operating speeds
Solution Approach 1:
The patent replaces the mechanical slip ring system with a hydraulic power transfer system. Hydraulic fluid is used to transmit power from the static field to the rotating field without mechanical contact, eliminating wear and maintenance issues associated with slip rings while maintaining power transfer capability.
Solution Approach 2:
The patent employs hydraulic coupling to transfer power across the static-rotating interface. A hydraulic motor in the rotating field converts hydraulic energy from the static field into mechanical rotation, enabling power transfer without direct mechanical connection and thus avoiding the reliability problems of slip rings.
2Reliability
If rotating hydraulic coupling diameter is reduced to maintain low PV value, then seal life improves and leakage decreases, but power transfer capacity is limited
Solution Approach 1:
The patent extends the hydraulic coupling axially along the propeller shaft to increase the effective area for power transfer. By utilizing the axial dimension rather than increasing radial diameter, the system maintains low PV values at the seals while achieving sufficient power transfer capacity through increased axial length of the coupling.
Solution Approach 2:
The hydraulic coupling is nested within the propeller shaft structure, with the static coupling positioned at the rear end of the shaft. This nested arrangement allows the hydraulic power transfer system to be integrated into the existing shaft geometry, maximizing space utilization while maintaining compact dimensions.
3Power
If static hydraulic power source is used with rotating hydraulic coupling, then power transfer is achieved, but leakage occurs and maintenance is required
Solution Approach 1:
The patent extracts the hydraulic power source from the rotating field and places it entirely in the static field. The hydraulic pump and reservoir are positioned statically, with only the hydraulic fluid being transferred to the rotating field through sealed couplings. This separation eliminates the need for rotating seals at the power source and minimizes leakage points.
Solution Approach 2:
The patent introduces a magnetic coupling as an intermediary between static and rotating fields for hydraulic fluid transfer. The magnetic coupling allows non-contact power and fluid transfer across the interface, eliminating mechanical seals and significantly reducing hydraulic fluid leakage while maintaining efficient power transfer.
4Ease of repair
If hydraulic actuator is statically mounted, then maintenance is easier, but power transfer to rotating propeller blades becomes complex
Solution Approach 1:
The patent replaces complex mechanical power transfer mechanisms with a hydraulic system. The statically mounted hydraulic actuator controls propeller blade pitch through hydraulic pressure, eliminating the need for complex mechanical linkages, gears, or belts that would be required to transfer power from a static to a rotating actuator.
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 enables efficient hydraulic power transfer to both propeller assemblies with reduced maintenance burdens, improved gear assembly stiffness, and reliable blade feathering capabilities, overcoming issues associated with previous designs.
Implementation Method 1
a first hydraulic rotating coupling mounted to a forward end of the static conduit... the first fluid supply lines fluidly communicating with the first hydraulic actuator via the first rotating coupling
Data Source
AI summary
An engine arrangement has a gear assembly that drives a first propeller assembly. The gear assembly is driven by a power drive shaft that joins to the gear assembly at a first side. The engine arrangement has a static conduit that extends along a longitudinal internal cavity of the power drive shaft. The conduit penetrates the gear assembly such that a portion of the conduit projects from an opposing second side of the gear assembly. The engine arrangement has one or more first fluid supply lines routed along the static conduit between a hydraulic pressure power source and the first hydraulic actuator. A first hydraulic rotating coupling is mounted to the projecting portion of the static conduit. The first fluid supply lines fluidly communicate with the first hydraulic actuator via the first rotating coupling.