Rotor Assembly With Elastic Restoration for Stable eVTOL Blade Pitch

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Solution Overview

Problem

Existing eVTOL aircraft face challenges in maintaining stability and control of rotor blades, particularly in the event of a failure in the drive unit, which can lead to uncontrollable pitch angles and reduced thrust.

Innovation Solution

Incorporation of a position restoration unit with opposing elastic bodies above and below the swash plate to generate restorative forces, maintaining the blade's pitch angle and ensuring stability by balancing these forces, even in the event of a drive unit failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a drive unit is used to adjust the swash plate position for blade pitch control, then the eVTOL can achieve controlled thrust and movement, but the system becomes vulnerable to drive unit failure which compromises stability and control

Engineering Contradiction:
Improveblade pitch controlVSAvoidstability control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The elastic bodies are pre-installed on opposite sides of the swash plate to generate restorative forces that counteract potential drive unit failures before they occur. These elastic bodies are positioned and tensioned in advance so that when drive unit failure happens, the pre-positioned elastic forces immediately activate to restore the swash plate to its neutral position, preventing loss of control.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The elastic bodies serve as a cushioning mechanism that absorbs and compensates for the shock of drive unit failure. By pre-tensioning these elastic elements on both sides of the swash plate, the system creates a safety buffer that gradually restores the swash plate position after failure, preventing sudden instability and giving the system time to adapt to the failure condition.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If elastic bodies are added to restore swash plate position after drive unit failure, then reliability improves, but device complexity increases

Engineering Contradiction:
Improvestability controlVSAvoidrotor assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The elastic bodies are integrated into the existing rotor assembly structure by mounting them on the swash plate assembly that already exists for pitch control. The elastic restoration mechanism merges with the conventional swash plate linkage system, sharing common mounting points and structural elements, thereby adding redundancy without creating a completely separate parallel system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The elastic bodies serve multiple functions: they provide restorative force after drive unit failure, contribute to the overall structural rigidity of the swash plate assembly, and work in conjunction with the normal pitch control mechanism during successful operation. This multi-functionality reduces the need for dedicated single-purpose components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 position restoration unit maintains consistent blade pitch angles, ensuring constant thrust and improved stability of the aircraft, even in the absence of a functional drive unit.

Implementation Method 1

at least one elastic body disposed below the swash plate unit... the first elastic body and the second elastic body may generate restorative force in opposite directions

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4606702A1Rotor assemblies and air mobility apparatus including same
Publication Date: 2025.08.27 HYUNDAI MOTOR CO LTD
  • EP4606702A1 patent drawingFigure 1
  • EP4606702A1 patent drawingFigure 2
  • EP4606702A1 patent drawingFigure 3

AI summary

A rotor assembly includes a main shaft including blades disposed along a circumference; a swash plate unit disposed to penetrate the main shaft and configured to move up and down along the main shaft; a blade link connecting the blade to the swash plate unit; and a position restoration unit disposed above and below the swash plate unit and configured to adjust a position of the swash plate.