Helicopter Rotor Elastomeric Dampers for Vibration Control
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Solution Overview
Problem
Existing helicopter rotor systems face challenges in effectively damping vibrations induced by lead-lag motion of blades, requiring damping devices that are not affected by centrifugal force, are lightweight and compact, and do not rely on operating fluids like oil for functionality.
Innovation Solution
The implementation of elastomeric dampers with embedded metal material, housed between the blades and connected by rigid rods, which twist elastically to dampen oscillations about specific axes, maintaining effectiveness across a wide range of rotation speeds and blade positions without hydraulic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional damping devices are used, then vibration damping is achieved, but the damping action is significantly affected by centrifugal force, reducing effectiveness over wide rotation speed ranges
Solution Approach 1:
The patent changes the physical state of the damping medium from liquid (oil) to solid (elastomeric material). This parameter change eliminates the harmful effect of centrifugal force on damping effectiveness, allowing the device to maintain reliable vibration damping across a wide range of rotation speeds without the performance degradation that plagues traditional liquid-based dampers
Solution Approach 2:
The patent replaces the hydraulic/mechanical system (liquid oil under pressure) with a solid elastomeric material that provides damping through elastic deformation. This substitution eliminates the dependency on centrifugal force and operating fluid dynamics, enabling consistent damping performance across varying rotation speeds
2Reliability
If conventional damping devices with operating fluid are used, then damping function is achieved, but construction and maintenance are complicated
Solution Approach 1:
The patent extracts and eliminates the operating fluid (oil) from the damping device, replacing it with a solid elastomeric material. This extraction removes the complexity associated with fluid containment, sealing, and hydraulic systems, resulting in a simpler construction that requires no maintenance of fluid systems
Solution Approach 2:
The elastomeric material provides self-contained damping functionality through its inherent elastic properties. The material automatically dampens vibrations without requiring external operating fluids, seals, or complex mechanical systems, making the device self-sufficient and maintenance-free
3Reliability
If heavy and compact damping devices are used, then vibration damping is achieved, but the overall weight of the rotor system increases
Solution Approach 1:
The patent uses composite materials (elastomeric material with embedded metal) to create a damping device that is both lightweight and effective. The elastomeric matrix provides damping through elastic deformation while the embedded metal elements enhance structural integrity and damping capacity, achieving vibration control without excessive weight
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 reduces vibrations associated with lead-lag movements, simplifies construction and maintenance, and reduces overall weight while maintaining damping performance, making the rotor system more efficient and easier to maintain.
Implementation Method 1
dampers for damping oscillation of the blades about respective axes C, which comprise respective portions movable integrally with the blades about respective axes C; and respective portions connected functionally to one another and elastically to respective portions movable integrally with the blades
Implementation Method 2
an elastomeric damper comprising a quantity of metal material embedded inside the elastomeric material, so the elastomeric damper is elastically deformable under load
Data Source
AI summary
A rotor for a helicopter, having a drive shaft rotating about a first axis; a hub angularly integral with the drive shaft about the first axis; and at least two blades projecting from the hub on opposite sides of the first axis and elongated along respective second axes crosswise to the first axis; each blade is movable with respect to the hub and to the other blade about a respective third axis crosswise to the respective second axis; the rotor has at least two dampers for damping oscillation of respective blades about the respective third axes, and which have respective first portions movable integrally with the respective blades about the respective third axes; and the dampers have respective second portions connected elastically to the respective first portions and functionally to each other.