Switching Device Insulation for Power Tool Heat Dissipation

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Solution Overview

Problem

Existing electrical power tools with switching devices face limitations in heat dissipation and electrical short-circuiting issues, preventing multiple switching devices from being effectively integrated due to direct contact between conductive parts and metal cases.

Innovation Solution

A switching device design where the conductive parts contact a circuit board and insulated portions contact a metal case through an insulating covering material, with the case filled with an insulating material to enhance heat dissipation and prevent electrical short-circuits, allowing multiple devices to be integrated without short-circuiting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the conductive part of the switching device directly contacts the metal case, then heat dissipation is improved, but electrical short-circuiting occurs between multiple switching devices

Engineering Contradiction:

Improveheat dissipationVSAvoidelectrical short-circuit prevention

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The switching device is divided into distinct functional zones: the conductive part for heat dissipation contact with the metal case, and the insulated portion covered by insulating covering material for electrical isolation. This segmentation allows simultaneous achievement of thermal conduction and electrical insulation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the switching device are given different electrical properties: the conductive part maintains high thermal conductivity for heat dissipation, while the insulated portion is covered with insulating material to prevent electrical short-circuits. This local differentiation resolves the contradiction between heat dissipation and electrical isolation.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If multiple switching devices are disposed in the metal case, then device functionality is enhanced, but electrical short-circuiting occurs between conductive parts

Engineering Contradiction:

Improvemultiple switching devices integrationVSAvoidelectrical short-circuit prevention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The insulating covering material acts as an intermediary layer between the conductive parts of multiple switching devices and the metal case. This intermediary prevents direct electrical contact and potential short-circuits while allowing thermal management through the circuit board and case structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Each switching device is segmented into conductive and insulated portions, enabling multiple devices to be densely integrated in the metal case without electrical interference between their conductive parts.

Inventive Principle:

Principle #1Segmentation

3Temperature

If the circuit board is embedded in the metal case filled with insulating material, then heat dissipation is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveheat dissipation characteristicsVSAvoidassembly process complexity

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The circuit board and metal case are merged into a unified heat dissipation structure, with the circuit board embedded in the case and both filled with insulating material. This merging creates an integrated thermal management system that improves heat dissipation while the insulating material provides both thermal and electrical functions.

Inventive Principle:

Principle #5Merging (Combining)

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 improves heat dissipation and prevents electrical short-circuits, enabling multiple switching devices to be integrated, enhancing the performance and reliability of electrical power tools by effectively managing heat and electrical insulation.

Implementation Method 1

The insulated portion of the switching device contacts the metal case via the insulating covering material

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

heat produced from the switching device can be effectively dissipated via conductive parts of the circuit board and the metal case

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2100702B1Electrical power tools

Publication Date: 2010.09.22 MAKITA CORP

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AI summary

An electrical power tool may include a switching device capable of controlling output power of a motor, a circuit board supporting the switching device, and a metal case receiving the circuit board. The switching device includes a conductive part and an insulated portion that is covered by an insulating covering material. The conductive part of the switching device contacts the circuit board. The insulated portion of the switching device contacts the metal case via the insulating covering material.