Helicopter Rotor Hub Damping Device Design
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Solution Overview
Problem
Helicopter rotor designs face challenges in managing vibration damping, as existing solutions either increase aerodynamic drag when located outward of the blades or induce stress and wear when located inward, leading to performance issues and safety concerns.
Innovation Solution
A helicopter rotor design with damping devices housed between the blade's coupling member and the hub, utilizing a V-shaped plate member with elastic connections, which allows for flexible movement without sliding, reducing wear and drag, and minimizing the size of the damping devices while enhancing their resistance to stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the damping device is located outwards of the blade, then the vibration damping effect is improved, but the aerodynamic drag increases which impairs performance and consumption
Solution Approach 1:
The damping device is nested within the rotor hub structure, specifically housed in a cavity formed by the hub and the blade's coupling member. This nesting approach allows the damping device to be positioned effectively without extending outward from the blade, thus maintaining vibration damping functionality while avoiding additional aerodynamic drag.
2Object-generated harmful factors
If the damping device is made as small as possible to reduce drag, then the aerodynamic drag is reduced, but the loads acting on the rotor may induce severe stress on, and even cause detachment of, the damping devices
Solution Approach 1:
The damping device is pre-positioned and secured within the rotor hub cavity before operation. The hub structure provides inherent mechanical support and constraint, cushioning the damping device against severe stresses induced by rotor loads. This prevents detachment while maintaining a compact size that minimizes aerodynamic drag.
3Object-generated harmful factors
If the damping device is located inwards of the blade, then the aerodynamic drag is reduced, but the damping device interacts with the portion of the blade connected to the hub, causing sliding movements that produce wear and localized heating
Solution Approach 1:
The damping device is extracted from the blade structure and relocated to be housed within the rotor hub cavity. This separation eliminates the interaction between the damping device and the blade's coupling portion, preventing sliding movements, wear, and localized heating. The damping function is maintained while the harmful interactions are removed.
4Object-generated harmful factors
If the damping device is located inwards of the blade, then the aerodynamic drag is reduced, but it makes it necessary to redesign the rotor hub due to size constraints
Solution Approach 1:
The rotor hub is designed with a multi-functional cavity that simultaneously serves as a structural component and a housing for the damping device. This universal design approach accommodates the damping device within the existing hub structure without requiring separate dedicated space or complex redesign, thus reducing drag while maintaining design simplicity.
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 design minimizes aerodynamic drag, reduces wear and stress on components, and prevents accidental detachment of damping devices, thereby improving helicopter performance and safety by effectively managing vibration without compromising the rotor's integrity or increasing drag.
Implementation Method 1
a connecting portion 13 connecting arms 12 and which engages a respective seat 9 of hub 2
Implementation Method 2
a number of damping devices 4 (only one shown in detail), each interposed between a respective blade 3 and hub 2 to reduce the vibration induced on the helicopter by rotor 1
Data Source
AI summary
There is described a rotor for a helicopter, having a hub rotating about a first axis; a number of blades projecting from the hub in respective longitudinal directions lying in a plane crosswise to the first axis, and each connected to the hub so as to be movable at least about a second axis crosswise to the first axis and to the relative longitudinal direction; and a number of damping devices for damping vibration of the helicopter, each interposed between a respective blade and the hub; each damping device has a plate member fixed, on one side, to the hub, elastically connected, on the opposite side, to the relative blade, and flexible, during movement of the blade, about a third axis coaxial with the second axis.