Reduction Gearbox Assembly Using Pre-Aligned Ring and Planet Gears

Solution Overview

Problem

Aircraft engine gearboxes, particularly those used in turboprop engines, add weight and complexity due to the need for a reduction gearbox to align high-speed turbine rotational energy with propeller torque, necessitating an improved assembly method for efficient and precise alignment of components.

Innovation Solution

A method and system for assembling a reduction gearbox involving the alignment of ring gears and planet gear assemblies within casing sections, utilizing alignment features for precise mechanical engagement and angular alignment, allowing for efficient assembly of the gearbox components without increasing weight or complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a reduction gearbox is used to reduce turbine rotational speed and increase torque, then the propeller can be driven at appropriate speed, but weight and complexity of the engine increase

Engineering Contradiction:

ImprovetorqueVSAvoidengine weight

Core Design Contradiction:

PowerVSWeight of moving object

Solution Approach 1:

The gearbox is divided into two separate casing sections (first casing section and second casing section) that can be assembled independently and then joined together. Each casing section contains specific gear components, allowing for modular manufacturing and assembly while reducing overall complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Alignment features are pre-formed on the ring gears and casing sections during manufacturing. These alignment features (such as keyed slots, dowel pins, or machined surfaces) ensure proper positioning of gear components before final assembly, eliminating the need for complex alignment procedures and reducing assembly time

Inventive Principle:

Principle #10Preliminary action

2Power

If a reduction gearbox is used to reduce turbine rotational speed and increase torque, then the propeller can be driven at appropriate speed, but device complexity increases

Engineering Contradiction:

ImprovetorqueVSAvoidgearbox complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The gearbox is divided into two separate casing sections (first casing section and second casing section) that can be assembled independently and then joined together. Each casing section contains specific gear components, allowing for modular manufacturing and assembly while reducing overall complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Alignment features act as intermediaries between the ring gears and casing sections, ensuring proper positioning and orientation during assembly. These features mediate the alignment process by providing predetermined reference points that guide the mating of components without requiring complex measurement or adjustment procedures

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If precise alignment of ring gears and planet gear assemblies is achieved through conventional methods, then proper gear meshing is obtained, but assembly time and complexity increase

Engineering Contradiction:

Improvegear alignment precisionVSAvoidassembly time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

Alignment features are pre-formed on the ring gears and casing sections during manufacturing. These alignment features (such as keyed slots, dowel pins, or machined surfaces) ensure proper positioning of gear components before final assembly, eliminating the need for complex alignment procedures and reducing assembly time

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The alignment features on the ring gears and casing sections automatically guide the components into proper alignment when mated together. The components self-align through the predetermined geometric relationships of the alignment features, eliminating the need for external alignment tools or complex adjustment procedures

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12104541B1Method and system for assembling a reduction gearbox

Publication Date: 2024.10.01 PRATT & WHITNEY CANADA CORP

AI summary

A method of assembling a reduction gearbox is provided that includes: a) aligning first and second ring gears by mounting the first ring gear in a first casing section in a first predetermined position and mounting the second ring gear in a second casing section in a second predetermined position, wherein the first and second casing sections mate with one another in a defined orientation; b) angularly aligning a plurality of planet gear assemblies relative to one another, each planet gear assembly having a main gear, a first lateral gear, and a second lateral gear coupled to one another; c) disposing the aligned planet gear assemblies between the first and second casing sections; and d) coupling the first and second casing sections together in the defined orientation with the first lateral gears meshed with the first ring gear and the second lateral gears meshed with the second ring gear.