Drive System Thermal Management via Fan-Coupled Electronics

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Solution Overview

Problem

Existing drive systems with electric motors face challenges in maintaining thermal stability due to the mismatch between motor operating temperatures and the thermal tolerance of electronic assemblies coupled to the rotor.

Innovation Solution

A drive system design where an electronic assembly is mechanically and thermally coupled to a fan wheel, which rotates at the same speed as the motor shaft, utilizing a fan wheel made of high thermal conductivity materials and featuring a thermally insulating element to manage heat dissipation, with detachable electrical contacts for the electronic assembly and rotor windings, and incorporating an inverter for control signal generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electronic assembly is mechanically coupled to the rotor of the electric motor, then the drive system achieves functional integration and compact design, but the electronic assembly is exposed to excessive heat from the motor windings causing thermal instability

Engineering Contradiction:
Improvestructural integrationVSAvoidthermal stability
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent divides the rotor assembly into functionally separate components: the motor windings remain in the stator housing while the electronic assembly is mounted on the rotor shaft. This segmentation allows independent thermal management for each component, enabling the electronic assembly to be positioned away from heat-generating windings while maintaining mechanical coupling for rotation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a thermally insulating element positioned between the rotor shaft and the electronic assembly. This intermediary component blocks heat transfer from the motor windings to the electronic assembly, protecting temperature-sensitive electronics while allowing mechanical coupling and rotation. The insulating element acts as a thermal barrier that maintains functional integration without thermal coupling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the electronic assembly is positioned outside the motor housing, then thermal stability is improved, but thermal coupling with heat-generating components is reduced

Engineering Contradiction:
Improvethermal stabilityVSAvoidheat dissipation efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent extracts the electronic assembly from the motor housing and mounts it on the rotor shaft externally. This extraction removes the electronic components from the thermal environment inside the housing, exposing them to ambient cooling air and reducing their exposure to motor winding heat. The electronic assembly remains functionally integrated through mechanical coupling while achieving thermal separation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If a thermally insulating element is added between the shaft and fan wheel, then heat flow to the electronic assembly is reduced, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveheat flow protectionVSAvoidcomponent quantity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent designs the rotor shaft to serve multiple functions simultaneously: it provides mechanical support for rotation, transmits torque from the motor, and incorporates thermal insulation properties to protect the electronic assembly. By integrating the insulating function into the shaft itself rather than adding a separate element, the design achieves thermal protection without increasing component quantity or manufacturing complexity.

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 configuration enhances thermal stability by effectively dissipating heat from both the motor windings and electronic assembly, protecting the electronic components from excessive heat while maintaining efficient operation and allowing for easy replacement of defective parts.

Implementation Method 1

The fan wheel can consist of a material with high thermal conductivity, for example aluminum alloys, other metal alloys and/or special ceramics

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a thermally insulating element can be arranged between the shaft and the fan wheel, which element minimizes heat flow from the heat-generating electrical functional groups via the shaft in the direction of the fan wheel or the electronic assembly

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

at least one fan which is driven directly or indirectly by means of the shaft and which generates a flow of cooling air

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP2994979B1Drive system
Publication Date: 2023.08.02 LENZE DRIVES
  • EP2994979B1 patent drawingFigure 1~2

AI summary

A drive system (100) comprises an electric motor (1) having a shaft (2); an electronic assembly (3); and a fan (4) driven by means of the shaft (2), the electronic assembly (3) being rigidly and thermally coupled to the fan (4).