Reduction Gearbox Assembly with Pre-Aligned Ring and Planet Gears

Solution Overview

Problem

Aircraft engine gearboxes, particularly those used in turboprop engines, face challenges due to their weight and complexity, which are exacerbated by the need for a reduction gearbox to manage the high rotational speed of turbines for propeller drive, leading to inefficiencies and room for improvement.

Innovation Solution

A method and system for assembling a reduction gearbox that involves aligning ring gears and casing sections with specific alignment features, angularly positioning planet gear assemblies using a coupler, and mechanically engaging these components to facilitate efficient gear meshing and torque distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a reduction gearbox is used to reduce turbine rotational speed for propeller drive, then the propeller can be driven at appropriate speed with increased torque, but the gearbox adds weight and complexity to the engine

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. Each casing section contains specific gear components, allowing for modular manufacturing and assembly, thereby reducing overall complexity while maintaining the torque multiplication function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Alignment features are pre-integrated into the casing sections and gear components during manufacturing. These pre-built alignment features (such as alignment pins, keyed surfaces, or machined reference surfaces) ensure that when the casing sections are assembled, the ring gears and planet gear assemblies automatically align correctly, eliminating the need for complex alignment procedures and reducing assembly complexity.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If traditional gearbox assembly methods are used, then all components can be assembled, but alignment of ring gears and planet gear assemblies requires significant time and precision

Engineering Contradiction:

Improvegear alignment precisionVSAvoidassembly time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

Alignment features are pre-integrated into the casing sections and gear components during manufacturing. These pre-built alignment features (such as alignment pins, keyed surfaces, or machined reference surfaces) ensure that when the casing sections are assembled, the ring gears and planet gear assemblies automatically align correctly, eliminating the need for complex alignment procedures and reducing assembly complexity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The alignment features are designed to automatically self-align the ring gears and planet gear assemblies when the casing sections are brought together. This self-aligning mechanism eliminates the need for external alignment tools or manual adjustment procedures, significantly reducing assembly time while maintaining high precision.

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If multiple separate assembly procedures are used for ring gears and planet gear assemblies, then each component can be positioned independently, but the overall assembly process becomes more complex and time-consuming

Engineering Contradiction:

Improveassembly easeVSAvoidassembly procedure complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the assembly of ring gears and planet gear assemblies into a single integrated procedure. The alignment features are designed so that when the first and second casing sections are assembled together, both the ring gears and planet gear assemblies align and mesh simultaneously in one operation, rather than requiring separate alignment and assembly steps for each component type.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Alignment features are pre-integrated into the casing sections and gear components during manufacturing. These pre-built alignment features (such as alignment pins, keyed surfaces, or machined reference surfaces) ensure that when the casing sections are assembled, the ring gears and planet gear assemblies automatically align correctly, eliminating the need for complex alignment procedures and reducing assembly complexity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4461992A1Method and system for assembling a reduction gearbox

Publication Date: 2024.11.13 PRATT & WHITNEY CANADA CORP

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AI summary

A method of assembling a reduction gearbox is includes: a) aligning first (50A) and second (50B) ring gears by mounting the first ring gear (50A) in a first casing section (44A) in a first predetermined position and mounting the second ring gear (50B) in a second casing section (44B) in a second predetermined position, wherein the first (44A) and second (44B) casing sections mate with one another in a defined orientation; b) angularly aligning a plurality of planet gear assemblies (48) relative to one another, each planet gear assembly (48) having a main gear (58), a first lateral gear (60), and a second lateral gear (62) coupled to one another; c) disposing the aligned planet gear assemblies (48) between the first (44A) and second (44B) casing sections; and d) coupling the first (44A) and second (44B) casing sections together in the defined orientation with the first lateral gears (60) meshed with the first ring gear (50A) and the second lateral gears meshed with the second ring gear (50B).