Portable Working Tool Cooling Ducts for Blockage Compensation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Cooling performance of portable work devices can be reduced due to blocked intake openings, leading to uneven cooling of the drive motor and electronic components, which can result in overheating and potential damage.

Innovation Solution

A portable work device with dual intake openings connected by a bypass duct, ensuring even cooling distribution by compensating for blocked intake openings through airflow redirection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If multiple intake openings are provided for cooling the drive motor, then the cooling performance is improved, but the risk of blockage increases and uneven cooling occurs when blockage happens

Engineering Contradiction:
Improvecooling performanceVSAvoidcooling reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

A bypass channel is introduced as an intermediary pathway connecting the first and second cooling air channels. When one intake opening becomes blocked, cooling air can flow through the bypass channel to compensate for the blockage, ensuring continuous and reliable cooling of the drive motor without overheating

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The bypass channel is designed in advance as a compensatory measure against potential future blockages. This preemptive design ensures that if either intake opening becomes blocked during operation, the system already has an alternative pathway ready to maintain cooling performance, preventing overheating before it occurs

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Device complexity

If cooling air is supplied through single or few intake openings, then the structure is simpler, but uneven cooling of the drive motor occurs

Engineering Contradiction:
Improvecooling system complexityVSAvoidcooling uniformity
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The cooling system is segmented into two separate cooling air channels: a first cooling air channel extending from the first intake opening to the first end of the motor housing, and a second cooling air channel extending from the second intake opening to the second end of the motor housing. This segmentation allows cooling air to be distributed to different regions of the motor housing simultaneously, ensuring uniform cooling across the entire drive motor

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the motor housing receive cooling air through dedicated channels tailored to their specific cooling needs. The first cooling air channel targets the first end of the motor housing while the second cooling air channel targets the second end, providing locally optimized cooling that ensures uniform temperature distribution across the drive motor

Inventive Principle:
Principle #3Local quality

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

Ensures consistent and reliable cooling of the drive motor and electronic components by evenly distributing cooling air, preventing overheating and potential damage.

Implementation Method 1

the first cooling air duct and the second cooling air duct are connected to each other via a bypass... the lack of cooling air at the blocked intake opening can be compensated for by cooling air flowing in via the bypass

Methodology Applied
Scientific EffectAirflow redirection:

Implementation Method 2

the drive motor comprises a fan impeller rotating about the rotational axis. During operation of the drive motor, the fan impeller generates a first cooling air stream flowing along the first cooling air duct and a second cooling air stream flowing along the second cooling air duct

Methodology Applied
Scientific EffectFan-induced airflow: Fan

Implementation Method 3

Cooling air can flow into the housing through the intake openings, cool the drive motor, and exit through an outlet opening

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP4230352B1Portable working tool
Publication Date: 2025.09.17 ANDREAS STIHL AG & CO KG
  • EP4230352B1 patent drawingFigure 1
  • EP4230352B1 patent drawingFigure 2~4
  • EP4230352B1 patent drawingFigure 5~7

AI summary

The invention relates to a portable work device comprising a housing (2), a tool (9) wherein a first intake opening (11) and a second intake opening (12) for cooling air for cooling the drive motor (5) are formed on the housing (2), a first cooling air duct (13) and a second cooling air duct (14), wherein the first cooling air duct (13) extends from the first intake opening (11) to the first end (7) of the motor housing (20) of the drive motor (5), and wherein the second cooling air duct (14) extends from the second intake opening (12) to the second end (8) of the motor housing (20) of the drive motor (5), wherein the first cooling air duct (13) and the second cooling air duct (14) are connected to each other via a bypass (15).