Radial Fan Cooling for Compact Industrial Truck Power Electronics

Solution Overview

Problem

Industrial truck power electronics face challenges in achieving sufficient cooling within limited installation space due to high heat generation and the need for large heat sinks, which conflicts with the goal of minimizing construction volume, especially when using axial fans.

Innovation Solution

The implementation of a radial fan system with a deflection element that redirects radially ejected air flow in an axial direction into the heat sink, allowing for efficient cooling while reducing the overall height of the heat sink and enabling a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If axial fans are used for cooling the heat sink, then cooling capacity is improved, but the overall height of the power electronics increases

Engineering Contradiction:

Improvecooling capacityVSAvoidoverall height

Core Design Contradiction:

TemperatureVSLength of stationary object

Solution Approach 1:

The patent inverts the conventional axial fan airflow direction by using a radial fan that draws air axially but expels it radially, then uses a deflecting element to redirect the airflow back axially into the heat sink. This inversion allows the fan to be positioned laterally rather than axially, reducing the heat sink height requirement while maintaining cooling capacity.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions from axial fan arrangement (requiring height in the axial dimension) to radial fan arrangement with lateral positioning. By changing the fan type from axial to radial and repositioning it laterally, the cooling system achieves the same function while reducing the critical height dimension of the heat sink.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the heat sink is made taller to accommodate axial fans, then sufficient cooling is achieved, but the installation space is exceeded

Engineering Contradiction:

Improvecooling efficiencyVSAvoidinstallation volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent inverts the conventional axial fan airflow direction by using a radial fan that draws air axially but expels it radially, then uses a deflecting element to redirect the airflow back axially into the heat sink. This inversion allows the fan to be positioned laterally rather than axially, reducing the heat sink height requirement while maintaining cooling capacity.

Inventive Principle:

Principle #13The other way round (Inversion)

3Temperature

If the fan diameter is increased to improve cooling capacity, then heat dissipation is enhanced, but the overall size of the power electronics increases

Engineering Contradiction:

Improveheat dissipationVSAvoidoverall footprint

Core Design Contradiction:

TemperatureVSArea of stationary object

Solution Approach 1:

The patent transitions from axial fan arrangement (requiring height in the axial dimension) to radial fan arrangement with lateral positioning. By changing the fan type from axial to radial and repositioning it laterally, the cooling system achieves the same function while reducing the critical height dimension of the heat sink.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 enables effective heat dissipation with a significantly lower overall height of the heat sink, reducing the structure's height by 25% to 37.5% compared to traditional axial fan arrangements, while maintaining sufficient cooling performance, allowing for a more compact power electronics system.

Implementation Method 1

a radial fan (20) for active cooling of the heat sink (10), wherein the radial fan (20) is designed to draw in air in an axial direction and to expel it radially

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Implementation Method 2

a deflecting element (26) radially connected to the radial fan (20) for deflecting at least a part of the airflow expelled radially by the radial fan (20) into the axial direction into the heat sink (10)

Methodology Applied

Scientific EffectFlow Deflection:

Implementation Method 3

The circuit board is in thermally conductive contact with the heat sink such that heat generated by the operation of the power semiconductors is dissipated into the heat sink

Methodology Applied

Scientific EffectThermal Conduction: Conduction (thermal)

Implementation Method 4

The heat sink has, in particular, a plurality of cooling fins

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentEP3784012B1Power electronics for an industrial truck

Publication Date: 2023.10.04 JUNGHEINRICH AG

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AI summary

Power electronics for a forklift truck, in particular for an integrated charger of the forklift truck, comprising a heat sink and a circuit board with power semiconductors arranged on the heat sink, characterized by a radial fan for active cooling of the heat sink, wherein the radial fan is designed to draw in air in an axial direction and to expel it radially, and by a deflecting element radially connected to the radial fan for deflecting at least a part of the airflow expelled radially by the radial fan into the axial direction into the heat sink.