Wind Turbine Main Shaft Snap Ring Retention Assembly

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Solution Overview

Problem

The existing locknut assembly for retaining the main shaft of wind turbines is costly to machine and poses safety risks due to high torque requirements for manual tightening and loosening during annual inspections.

Innovation Solution

A retention assembly using a snap ring engaged within a ring groove on the main rotor shaft, with an optional relief groove to reduce stress and eliminate the need for a locknut, providing a secure backup retention mechanism without the drawbacks of the conventional locknut system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locknut assembly is used to retain the main rotor shaft, then the shaft retention reliability is improved, but the manufacturing cost and machining complexity increase significantly

Engineering Contradiction:

Improveshaft retention reliabilityVSAvoidmanufacturing cost and machining complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the locknut assembly from the shaft retention system, replacing it with a simplified groove-based retention mechanism. The locknut and its threaded holes are completely removed, keeping only the essential retention function through grooves cut in the shaft that engage with retaining rings or similar components.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive, precision-machined locknut assembly with a simpler, less costly groove structure. The grooves are cut to a specified depth and width, engaging with retaining components that are easier and cheaper to manufacture than precision locknuts, thereby reducing overall manufacturing cost while maintaining retention reliability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If a locknut assembly is used to retain the main rotor shaft, then the shaft retention reliability is improved, but the operational safety deteriorates due to high torque requirements

Engineering Contradiction:

Improveshaft retention reliabilityVSAvoidoperational safety risks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the locknut assembly entirely, eliminating the source of high-torque hazards. By replacing the threaded locknut mechanism with a groove-based retention system, the design eliminates the need for high-torque tightening operations that pose safety risks to technicians during installation and maintenance.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potentially harmful high-torque locknut tightening operation into a safe, low-torque groove engagement mechanism. The grooves are designed to engage retaining components through controlled interference fits or mechanical interlocking that requires minimal torque, transforming a hazardous operation into a safe one while maintaining retention reliability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If a locknut assembly is used to retain the main rotor shaft, then the shaft retention reliability is improved, but the maintenance complexity and time consumption increase

Engineering Contradiction:

Improveshaft retention reliabilityVSAvoidmaintenance complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent eliminates the locknut assembly and its associated maintenance requirements. The groove-based retention system requires no periodic tightening, torque verification, or adjustment, thereby simplifying maintenance procedures and reducing the time and complexity of annual inspections compared to locknut systems that require spanner wrench operations.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If threads are machined on the main rotor shaft for locknut engagement, then the shaft retention reliability is improved, but the manufacturing time and cost increase

Engineering Contradiction:

Improveshaft retention reliabilityVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent removes the threaded hole machining operation from the manufacturing process. By replacing the locknut engagement system with a groove-based retention mechanism, the design eliminates time-consuming thread cutting operations while maintaining the essential shaft retention function through simpler groove cutting and component engagement.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS9249782B2Snap ring retention assembly for a main shaft in a wind turbine

Publication Date: 2016.02.02 GE INFRASTRUCTURE TECH LLC

AI summary

A retention assembly for securing a main rotor shaft in a wind turbine relative to a pillow block is provided. A main rotor shaft extends through a pillow block, and a ring groove is defined in an outer circumferential surface of the main rotor shaft axially offset from the pillow block. A snap ring is engaged within the ring groove, wherein the snap ring and ring groove are designed to achieve a design axial load capacity.