Power Tool Controller Case Cooling With Thick-Wall Heat Transfer

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Solution Overview

Problem

Existing power tool controllers face inefficiencies in cooling due to insufficient reach of cooling air, leading to inadequate heat dissipation despite higher motor output and generated heat.

Innovation Solution

The controller case incorporates a thick wall portion for heat absorption and transfer to a separate low temperature portion, utilizing a heat pipe for direct heat transfer to the power tool main body, and a heat pipe surface-contacting the electric element for enhanced heat dissipation, even when cooling air does not reach the controller effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling air is introduced from the intake port to cool the controller, then cooling efficiency is improved, but the cooling air may not sufficiently reach the controller due to limited arrangement configurations of electric elements

Engineering Contradiction:

Improvecontroller temperatureVSAvoidcooling air reachability

Core Design Contradiction:

TemperatureVSEase of operation

Solution Approach 1:

The controller case is divided into a thick wall portion and a general portion, creating distinct thermal zones. The thick wall portion specifically contacts the electric element to provide localized heat dissipation, while the general portion maintains structural integrity and houses other components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thick wall portion acts as an intermediary thermal conductor between the electric element and the external environment. It directly contacts the heat-generating electric element and transfers heat to the external air, serving as a dedicated heat dissipation pathway that does not depend on cooling air reaching the entire controller.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If a thick wall portion is added to the controller case for heat transfer, then heat dissipation efficiency is improved, but device complexity increases

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidcontroller case structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The thick wall portion is implemented only at the specific location where heat dissipation is needed (contacting the electric element), rather than uniformly thickening the entire controller case. This localized approach provides effective heat dissipation while minimizing additional material usage and structural complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The thick wall portion is integrated into the controller case as a single molded structure rather than being added as a separate component. This merging of the heat dissipation feature into the base case structure avoids increasing assembly complexity and maintains manufacturing simplicity.

Inventive Principle:

Principle #5Merging (Combining)

3Temperature

If the controller case is made of material with high thermal conductivity (120 to 200 W/mK), then heat transfer capability is improved, but manufacturing constraints increase

Engineering Contradiction:

Improvethermal conductivityVSAvoidmaterial selection flexibility

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent specifies a thermal conductivity range (120 to 200 W/mK) rather than requiring a specific material property. This parameter range allows selection from multiple material options (such as certain aluminum alloys or magnesium alloys) that meet the thermal performance requirement while considering manufacturability, cost, and other practical factors.

Inventive Principle:

Principle #35Parameter changes

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 ensures effective cooling of the controller, improving thermal conductivity and maintaining efficient heat dissipation regardless of air flow, thereby addressing the inefficiencies in existing cooling methods.

Implementation Method 1

when heat is applied to the thick wall portion of the controller case from the electric element on the electric circuit board, the applied heat that is transferred from the electric element can be transferred to a general portion separate from the thick wall portion due to heat uniformity

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a high temperature portion of the controller, similar to the high temperature portion mentioned above, is connected to a low temperature portion of a power tool main body of the power tool through a heat pipe

Methodology Applied

Scientific EffectHeat pipe: Heat Pipe

Data Source

PatentUS11219957B2Controller and power tool including the same

Publication Date: 2022.01.11 MAKITA CORP

AI summary

A controller 50 that controls a power tool such as, for example, a portable circular saw includes a controller case 70 that houses an electric circuit board 60. Electric elements 61, 62 that generate heat and/or are to be cooled on the electric circuit board 60 contact a thick wall portion 73b of the controller case 70, resulting in heat dissipation resulting in effective cooling of the controller 50.