Undulating Swashplate Track for Rotorcraft Vibration Control
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Solution Overview
Problem
Rotorcrafts experience excessive vibrations due to hub shear loads, out-of-balance components, or worn bearings, which hinder their performance.
Innovation Solution
A rotorcraft swashplate assembly with a rotationally fixed swashplate, a rotatable swashplate, multiple pitch change links, and an annular track with actuators that undulate to change the pitch of rotor blades at specific azimuth locations, counteracting rotational vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional swashplate design is used, then structural simplicity is maintained, but rotorcraft vibrations increase
Solution Approach 1:
The swashplate assembly incorporates movable bearings that can dynamically adjust their positions radially inward and outward along the annular track. This dynamic adjustment capability allows the system to adapt to varying vibration conditions and counteract rotorcraft vibrations through controlled movement of the pitch change links, transforming a static structure into a dynamic vibration control system.
Solution Approach 2:
The swashplate assembly is divided into multiple independent movable bearings distributed around the annular track. Each bearing can move independently radially, allowing localized vibration control at different azimuth positions. This segmentation enables the system to address vibration issues at specific locations without affecting the entire swashplate assembly.
2Object-affected harmful factors
If multiple movable bearings are added to counteract vibrations, then vibration reduction is achieved, but device complexity increases
Solution Approach 1:
The movable bearings serve multiple functions: they support the pitch change links, enable radial movement for vibration control, and work collectively with the actuators to adjust the pitch of rotor blades at different azimuth locations. This multi-functionality reduces the need for separate dedicated vibration control components.
Solution Approach 2:
The vibration control function is merged with the existing swashplate structure by integrating movable bearings into the annular track. The actuators are combined with the bearing assembly, allowing both support and control functions to be performed by a single integrated component rather than separate elements.
3Manufacturing precision
If actuators are used to move bearings independently, then pitch control precision is improved, but manufacturing complexity increases
Solution Approach 1:
The annular track is pre-configured with multiple actuators positioned at specific locations around the swashplate. These actuators are prepared in advance to move the bearings radially inward or outward at predetermined azimuth positions, enabling precise pitch control without requiring complex real-time adjustment mechanisms during operation.
Data Source
AI summary
A rotorcraft swashplate assembly includes a rotationally fixed swashplate fixed against rotating with a rotorcraft rotor. The swashplate assembly also includes a rotatable swashplate coupled to the rotor to rotate with the rotor. The swashplate assembly also includes multiple pitch change links, each pitch change link coupled to a respective rotor blade and to the rotatable swashplate to rotate with the rotor. The swashplate assembly also includes an annular track coupled to the rotationally fixed swashplate and configured to support each pitch change link riding on the annular track as each pitch change link rotates with the rotor. The track includes multiple bearings upon which a pitch change link rides, and actuators that move the bearings changing a shape of the annular track and thereby the pitch of each rotor blade as each pitch change link rides on the annular track during rotation of the rotor blades.