Rotor Shaft-Integrated Gearbox for Compact Wind Turbine Drivetrains

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Solution Overview

Problem

Existing drive train arrangements in wind turbines are complex, lengthy, and heavy, complicating assembly and maintenance, and require disassembly of the rotor for component removal.

Innovation Solution

A drivetrain arrangement with a gearbox integrated into the rotor shaft, a stationary machine support between the generator and gearbox, and a compact design that allows components to be removed without disassembling the rotor, utilizing a torsionally rigid coupling and flexible coupling for torque transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a gearbox is installed between the rotor and generator, then the weight of the rotor and nacelle is reduced, but the device complexity increases

Engineering Contradiction:
Improveweight of rotor and nacelleVSAvoiddevice complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The gearbox is integrated into the rotor shaft structure, merging two previously separate components (gearbox and rotor shaft) into a single unified assembly. This integration maintains the weight reduction benefit while simplifying the overall device structure by eliminating the need for separate mounting arrangements and reducing the number of external connections required.

Inventive Principle:
Principle #5Merging (Combining)

2Power

If all components are arranged sequentially, then the power transmission is straightforward, but the overall length of the drivetrain increases

Engineering Contradiction:
Improvepower transmissionVSAvoidoverall length of drivetrain
Core Design Contradiction:
PowerVSLength of moving object

Solution Approach 1:

The gearbox is positioned within the hollow interior of the rotor shaft, creating a nested configuration where one component (gearbox) is placed inside another (rotor shaft). This nesting arrangement allows power transmission components to be compactly arranged without increasing the overall axial length of the drivetrain, while maintaining efficient power flow from the rotor through the gearbox to the generator.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Length of moving object

If the gearbox is fully integrated into the rotor shaft, then the compactness is improved, but the ease of maintenance deteriorates

Engineering Contradiction:
ImprovecompactnessVSAvoidease of maintenance
Core Design Contradiction:
Length of moving objectVSEase of repair

Solution Approach 1:

The integrated drivetrain is divided into modular segments (rotor shaft with integrated gearbox, generator, and support structure) that can be independently accessed and maintained. The gearbox is positioned such that it can be serviced without complete disassembly of the rotor, allowing maintenance personnel to access internal gearbox components through designated service ports or by removing specific sections of the rotor shaft assembly.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If the rotor must be dismantled to remove components, then the integration is improved, but the time required for assembly and maintenance increases

Engineering Contradiction:
Improveintegration levelVSAvoidassembly and maintenance time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The gearbox is extracted from the traditional position at the end of the rotor shaft and repositioned within the hollow rotor shaft structure. This extraction and repositioning allows the gearbox to be accessed and removed independently without requiring complete disassembly of the rotor blades and hub, significantly reducing maintenance time while maintaining the benefits of integration.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design achieves a more compact and lighter drivetrain with simplified assembly and maintenance, maintaining high power density and efficiency while absorbing reaction torques and vibrations.

Implementation Method 1

The stationary machine support absorbs the reaction torques of the gearbox and the generator

Methodology Applied
Scientific EffectTorque: Torque

Implementation Method 2

the gearbox is connected to the rotor shaft by means of a torsionally rigid coupling. The compact design and backlash-free, angularly accurate torque transmission due to very high torsional stiffness are advantageous in this configuration

Methodology Applied
Scientific EffectTorsional stiffness:

Implementation Method 3

the transmission is designed as a planetary gear unit. The planetary gear unit is characterized by high efficiency and, due to its compact design, allows for a reduction in overall length while maintaining high power density

Methodology Applied
Scientific EffectPlanetary gearing: Epicyclic Gearing

Data Source

PatentEP3767102B1Drive train assembly
Publication Date: 2025.11.12 RENK AG
  • EP3767102B1 patent drawingFigure 1

AI summary

The invention relates to a drive train arrangement, preferably for a wind turbine, comprising a rotor shaft (2), a generator (5) and a gearbox (1) which is connected directly or indirectly to the rotor shaft (2) and the generator (5), wherein the gearbox (1) is at least partially or completely integrated into the rotor shaft (2).