Epicyclic Gearbox External Annulus Input

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Solution Overview

Problem

Epicyclic gearboxes face challenges in transferring motive power from an exterior source to interiorly positioned input elements without additional structural elements, leading to increased mass and dimensions, which limits their application in compact designs requiring high torque output.

Innovation Solution

An axially compact, reduced mass epicyclic gearbox with an integral arrangement of gearing elements, including an external annular gear and stepped planet gears supported by a floating planet carrier, directly transfers power from an external source to an internal sun gear stage, eliminating the need for additional structural elements and optimizing load sharing and mesh frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If additional structural elements are added to transfer power from exterior source to interior input elements, then power transfer capability is improved, but gearbox mass and dimensions increase

Engineering Contradiction:

Improvepower transfer capabilityVSAvoidgearbox mass

Core Design Contradiction:

PowerVSWeight of moving object

Solution Approach 1:

The patent merges the power transfer function with the existing gearbox structural elements. The exterior annular gear is integrated directly with the gearbox housing, and the interior sun gear is combined with the output shaft assembly, eliminating the need for separate power transfer structures and reducing overall gearbox mass while maintaining power transfer capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gearbox elements are designed to serve multiple functions simultaneously. The annular gear structure serves both as a structural component of the gearbox housing and as the power input element. The sun gear assembly serves both as the power output element and as part of the output shaft support structure, reducing the need for additional dedicated power transfer components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Power

If additional structural elements are added to transfer power from exterior source to interior input elements, then power transfer capability is improved, but gearbox dimensions increase

Engineering Contradiction:

Improvepower transfer capabilityVSAvoidgearbox dimensions

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a nested arrangement where the interior sun gear and planet gears are positioned within the annular gear structure. This nested configuration allows compact packaging of multiple gear stages within a limited radial space, minimizing gearbox outer dimensions while accommodating all necessary power transfer elements

Inventive Principle:

Principle #7Nested doll (Nesting)

3Force

If multiple planet elements are added to distribute load, then torque density is improved, but device complexity increases

Engineering Contradiction:

Improvetorque densityVSAvoidgearing arrangement complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent applies local quality by positioning planet gears at specific angular intervals around the sun gear to optimize load distribution. The planet gears are strategically placed to engage with both the sun gear and annular gear at optimal contact points, providing effective load sharing without requiring an excessive number of planet elements, thus balancing torque density with manageable complexity

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10807467B2Epicyclic gearbox

Publication Date: 2020.10.20 WHEELTUG PLC

AI summary

An epicyclic gearbox with an integral arrangement of meshing gear elements, including an annulus gear, planet gears, and sun gears, to transfer power from a motive power source to a driven element with a range of applications is provided. The annulus gear, in contact with the power source, forms an exterior gearbox input and is in meshing contact with a number of stepped planet gears supported on floating planet carriers. Each stepped planet gear is positioned internally of the annulus gear and includes two planet stages in meshing contact with corresponding sun gear stages. One of the sun gear stages is an interior gearbox output and transfers power to a machine or device to be driven. Meshing surfaces of the gear elements support helical teeth or spur teeth, with numbers of teeth on meshing gear elements selected for optimal torque transfer from the exterior input to the interior output.