Transmission Cooling Fan Layout for Passive Oil Heat Dissipation

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Solution Overview

Problem

Existing gearboxes and transmissions face inefficiencies in heat dissipation, particularly from frictional energy generated by bearings and meshing gears, which are not effectively managed by existing cooling systems.

Innovation Solution

A cooling arrangement integrated with a fan is designed, where the fan is rotationally fixed to a transmission shaft, conveying air through coolers while oil flows through these coolers, with a passive pump driven by the gearbox shaft, allowing for efficient heat transfer from oil to ambient air.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a cooling arrangement with active pump and fan is used, then heat dissipation efficiency is improved, but device complexity and energy consumption increase

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling arrangement is designed to operate passively without external power sources. The pump is driven by the rotation of the transmission shaft itself, and the fan is driven by the rotation of the cooling unit, enabling the system to cool itself using the existing motion in the transmission system.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The cooling arrangement is integrated directly into the transmission housing, with the pump, cooler, and fan forming a unified passive system. The pump is combined with the transmission shaft rotation, and the cooler is embedded in the housing, merging cooling functions with the existing transmission structure.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If a passive cooling arrangement is used, then device complexity is reduced, but heat dissipation efficiency may be insufficient

Engineering Contradiction:
Improvecooling system complexityVSAvoidheat dissipation efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The cooling system uses fluid dynamics principles where the rotating fan creates a pressure difference to draw ambient air through the cooler, and the pump utilizes rotational motion to circulate lubricating oil through the cooling channels. This passive pneumatic-hydraulic approach achieves efficient heat transfer without complex active control systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system changes the flow rate parameters of oil and air based on the rotational speed of the transmission. As the transmission rotates faster, the pump delivers more oil flow and the fan moves more air through the cooler, automatically adapting the cooling capacity to the heat generation level without external control.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If multiple coolers are arranged in a polygonal configuration, then heat dissipation surface area is increased, but manufacturing complexity increases

Engineering Contradiction:
Improveheat dissipation surface areaVSAvoidcooler arrangement complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The cooling system is divided into multiple identical cooler units arranged in a polygonal pattern around the transmission shaft. Each cooler is a separate, standardized module with oil inlet/outlet connections, allowing them to be manufactured independently and assembled in various polygonal configurations (triangle, square, pentagon, etc.) based on space availability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The polygonal arrangement of coolers serves multiple functions: it maximizes the heat dissipation surface area, distributes the thermal load evenly around the transmission, and allows flexible adaptation to different housing geometries. The same cooler design can be used in triangular, square, or pentagonal arrangements depending on the available space.

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 design enables passive, efficient cooling of lubricating oil, facilitating its reuse within the transmission for lubrication and cooling, with a simple manufacturing process and temperature-dependent flow control, ensuring effective heat dissipation and reduced manufacturing complexity.

Implementation Method 1

The oil-flowing section of the fan and the air-flowing section of the fan are connected to each other in a thermally conductive manner. This allows heat to flow from the oil through both sections of the cooler to the ambient air.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an air flow conveyed by the fan flows through the cooler, wherein an oil flow conveyed by a pump flows through the cooler

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

an air flow conveyed by the fan flows through a section of each cooler, particularly in an axial direction, i.e., parallel to the direction of the fan's rotation axis

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 4

The oil flow conveyed by a pump flows through the cooler. The oil flow pump draws oil from the transmission sump and conveys it, particularly via a filter, through the cooler.

Methodology Applied
Scientific EffectHydraulic pumping: Pump

Data Source

PatentEP4165325B1Transmission comprising a cooling arrangement and a fan
Publication Date: 2025.07.09 SEW EURODRIVE GMBH & CO KG
  • EP4165325B1 patent drawingFigure 1
  • EP4165325B1 patent drawingFigure 2
  • EP4165325B1 patent drawingFigure 3

AI summary

The invention relates to a transmission comprising a cooling arrangement and a fan, wherein: the fan is connected to a first shaft of the transmission for conjoint rotation, in particular to a driving shaft of the transmission; the cooling arrangement has a cooler unit; the cooler unit has at least one cooler; an air stream conveyed by the fan flows through the cooler; and an oil stream conveyed by a pump flows through the cooler.