Integrated Epicyclic Gear Layout for Compact High Gear Ratios

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Solution Overview

Problem

Existing gear devices in aircraft struggle to achieve high gear ratios in a compact design while maintaining simplicity and manufacturability, which is essential for efficient torque conversion in flight control systems.

Innovation Solution

The integration of two epicyclic gears with kinematically similar but non-identical components, where specific input stage components are fixed to corresponding output stage components, allowing for a high gear ratio in a compact and easily manufacturable gear device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single epicyclic gear is used, then the design is simple and easy to manufacture, but the gear ratio is limited and the device size increases

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidgear ratio
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines two epicyclic gear stages into a single integrated device where the input stage and output stage share common components (sun, carrier, ring). This merging allows the device to achieve a compounded gear ratio equivalent to two separate stages while maintaining a simpler structure than two independent gear devices, and easier manufacturing than a single complex high-ratio stage.

Inventive Principle:
Principle #5Merging (Combining)

2Volume of stationary object

If two epicyclic gears are integrated with fixed connections, then the gear ratio increases in a compact design, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvedevice sizeVSAvoidcomponent alignment
Core Design Contradiction:
Volume of stationary objectVSManufacturing precision

Solution Approach 1:

By merging the input and output stages to share common components (the sun, carrier, and ring are common to both stages), the patent reduces the total number of interfaces and connection points compared to two separate stages. This reduces the cumulative manufacturing precision requirements while achieving compact high-ratio gearing.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4375539A1Gear device
Publication Date: 2024.05.29 GOODRICH ACTUATION SYST
  • EP4375539A1 patent drawingFigure 1
  • EP4375539A1 patent drawingFigure 2
  • EP4375539A1 patent drawing

AI summary

A gear device for a gear system for an aircraft, the gear device comprising: an input stage epicyclic gear comprising an input stage sun, an input stage carrier and an input stage ring; and an output stage epicyclic gear comprising an output stage sun, an output stage carrier and an output stage ring, wherein a first input stage component of the input stage sun, the input stage carrier and the input stage ring is fixed to a corresponding first output stage component of the output stage sun, the output stage carrier and the output stage ring, wherein a second input stage component of the input stage sun, the input stage carrier and the input stage ring is fixed to a corresponding second output stage component of the output stage sun, the output stage carrier and the output stage ring, wherein the second input stage component is different from the first input stage component, wherein a third input stage component of the input stage sun, the input stage carrier and the input stage ring is held stationary, wherein the third input stage component is different from the first input stage component and the second input stage component, wherein a third output stage component is connectable to an output shaft, the third output stage component corresponding to the third input stage component.