Hydroelastic Damper Floating Piston for Elastomer Isolation
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Solution Overview
Problem
Existing hydroelastic dampers for rotorcrafts face challenges in optimizing the lifetime of elastomer materials due to degradation from hydraulic fluid, particularly under varying pressures, temperatures, and chemical compositions, and suffer from fatigue and cavitation issues.
Innovation Solution
A hydroelastic damper design featuring a floating piston that isolates the elastomer resilient member from hydraulic fluid, minimizing radial forces and preventing fluid contact, made from lightweight materials like aluminum alloys to extend the lifespan of the piston and associated components, and incorporating modular design for maintenance and cost optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic fluid is in contact with elastomer material of the resilient member, then the hydroelastic damper can provide damping function, but the hydraulic fluid degrades the elastomer and reduces its lifetime
Solution Approach 1:
A floating piston is introduced as an intermediary element between the hydraulic fluid and the elastomer resilient member. The piston is movable relative to both the inner and outer strength members, creating a barrier that prevents direct contact between the hydraulic fluid and elastomer material, thereby eliminating degradation while maintaining the damping function.
Solution Approach 2:
The internal structure of the hydroelastic damper is segmented into distinct chambers: a first hydraulic chamber containing hydraulic fluid, a second hydraulic chamber, and an intermediate chamber containing the elastomer resilient member. The floating piston divides these chambers, allowing the system to maintain damping functionality while preventing harmful interactions between hydraulic fluid and elastomer.
2Reliability
If a floating piston is introduced to isolate elastomer from hydraulic fluid, then elastomer degradation is prevented, but the device complexity increases
Solution Approach 1:
The floating piston is designed to move freely relative to the inner and outer strength members without requiring complex sealing mechanisms or actuation systems. It automatically positions itself based on pressure differentials and mechanical constraints, providing isolation functionality through its own movement rather than requiring external control systems.
Solution Approach 2:
The floating piston serves multiple functions simultaneously: it acts as a barrier between hydraulic fluid and elastomer, provides mechanical guidance through its movement constraints, and contributes to the overall structural integrity of the damper assembly, thereby justifying its addition through multiple benefits rather than a single function.
3Duration of action of stationary object
If lightweight materials like aluminum alloys are used for the floating piston, then the lifespan of the piston and associated components is extended, but the radial forces on the piston increase
Solution Approach 1:
The design accepts the trade-off of increased radial forces on the floating piston by changing the material parameter to lightweight aluminum alloys. This material substitution extends the lifespan of the piston and associated components despite the increased force exposure, as the lightweight material provides better fatigue resistance and corrosion resistance over time.
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 solution effectively protects elastomer materials from hydraulic fluid, reducing degradation and fatigue, minimizing cavitation risks, and optimizing the lifespan of the damper components while allowing for easier maintenance and reduced costs.
Implementation Method 1
a first floating piston that is movable at least in translation along the longitudinal axis relative to the first inner strength member and to the first outer strength member, said first hydraulic chamber having a volume that is variable and that is defined at least by said first floating piston and said first wall, said first floating piston hydraulically isolating said first resilient member from the fluid
Implementation Method 2
a first resilient member secured to the first outer strength member and to the first inner strength member so as to provide resilient return of the first outer strength member and of the first inner strength member towards a rest position
Implementation Method 3
minimizing cavitation risks
Data Source
AI summary
A hydroelastic damper comprising at least a first resilient assembly that is provided with a first inner strength member engaged at least in part in a first outer strength member, a first resilient member providing resilient return for the first outer strength member and the first inner strength member towards a rest position (POSREP). The hydroelastic damper comprises at least one hydraulic assembly provided with a first hydraulic chamber and a second hydraulic chamber in communication with each other via a connection provided in a first wall of the hydraulic assembly. A first floating piston is movable at least in translation along the longitudinal axis relative to the first inner strength member and to the first outer strength member, the first hydraulic chamber being defined at least by the first floating piston and the first wall in order to protect the first resilient member.