Insulated Feedthrough Tube Mounting for Thermal Expansion Isolation

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Solution Overview

Problem

Integrated drive trains in wind turbines face issues with stray currents causing damage to gears and rolling bearings due to voltage flashovers, and the compact design limits the adequate dimensioning of torque-transmitting components, particularly electrical insulation, which is further complicated by temperature fluctuations affecting the feed-through pipe's length and diameter.

Innovation Solution

An electrically insulating fixing means is used to isolate the feed-through tube from the transmission components, allowing axial mobility to compensate for thermal expansion while preventing leakage currents, and an electrically insulating clutch ensures complete insulation between the transmission and generator, utilizing a conductive feed-through tube and a base body with matching thermal expansion coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the feedthrough tube is electrically insulated by fixed insulation, then stray currents are blocked, but the feedthrough tube becomes jammed due to thermal expansion differences

Engineering Contradiction:
Improveelectrical insulationVSAvoidjaming risk
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies the dynamics principle by making the feedthrough tube axially movable relative to the fixing means instead of being rigidly fixed. This allows the tube to expand and contract axially with temperature changes while maintaining electrical insulation through the insulating fixing means, preventing jaming while ensuring reliable insulation against stray currents.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses an insulating fixing means as an intermediary element between the feedthrough tube and the transmission component. This intermediary provides electrical insulation to block stray currents while allowing axial movement, thus preventing direct contact that would cause jaming due to thermal expansion differences.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the feedthrough tube is rigidly fixed for stable insulation, then insulation is maintained, but thermal expansion causes jamming

Engineering Contradiction:
Improveinsulation stabilityVSAvoidthermal adaptability
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The fixing means is designed to allow axial movement of the feedthrough tube while maintaining radial insulation stability. The insulating fixing means provides stable electrical isolation in the radial direction while permitting dynamic adjustment in the axial direction to accommodate thermal expansion.

Inventive Principle:
Principle #15Dynamics

3Reliability

If insulation components are enlarged for adequate dimensioning, then insulation performance improves, but available space is insufficient in integrated drive train

Engineering Contradiction:
Improveinsulation performanceVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the functions of mechanical fixing and electrical insulation into a single insulating fixing means. This integrated component eliminates the need for separate insulation elements, achieving adequate insulation performance while minimizing the volume required in the compact integrated drive train space.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulating fixing means serves multiple functions simultaneously: it provides mechanical support for the feedthrough tube, ensures electrical insulation to block stray currents, and allows axial movement for thermal expansion. This multi-functionality reduces the overall space requirement compared to multiple separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This solution effectively prevents damage from stray currents by ensuring reliable electrical insulation within the compact integrated drive train design, maintaining axial mobility and complete electrical isolation despite temperature fluctuations, thus safeguarding against voltage flashovers and dimensional changes.

Implementation Method 1

the length of the feedthrough tube changes axially with temperature fluctuations. At the same time, the diameter of the feedthrough tube changes. Due to different thermal expansion coefficients of the feedthrough tube and the materials considered as electrical insulators

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3795862B2Insulated feed-through pipe
Publication Date: 2024.12.18 ZF FRIEDRICHSHAFEN AG
  • EP3795862B2 patent drawingFigure 1~2

AI summary

The invention relates to an arrangement comprising a gearbox, a feedthrough tube (103), and a fixing means (101); wherein the feedthrough tube (103) is fixed in the gearbox by means of the fixing means (101). The fixing means (101) is electrically insulating with respect to the feedthrough tube (103).