Brushless Motor Switching Element Spacing in Power Tool Grip

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Solution Overview

Problem

In electric power tools using DC brushless motors, the conventional arrangement of switching elements behind the motor increases the tool's length, complicating heat management for electronic components and requiring additional protective measures.

Innovation Solution

The switching element is positioned inside the grip portion, spaced from the electronic circuit board, with a heat radiation or insulation material applied to prevent heat transfer, allowing for compact design without lengthening the tool and reducing heat protection needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the switching element is arranged behind the DC brushless motor, then the switching element can be properly positioned for operation, but the entire length of the electric power tool increases

Engineering Contradiction:

Improveswitching element operationVSAvoidentire length of electric power tool

Core Design Contradiction:

Ease of operationVSLength of moving object

Solution Approach 1:

The switching element is moved from the conventional position behind the motor to the grip portion, utilizing a different spatial dimension. This repositioning allows the switching element to be accessible from the side rather than requiring extended length behind the motor, thereby reducing the overall tool length while maintaining operational accessibility

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If the switching element and electronic component are mounted to the same electric circuit board, then device complexity is reduced, but heat protection measures must be taken to protect the electronic component from heating

Engineering Contradiction:

Improvecircuit board configurationVSAvoidheat affecting electronic component

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The circuit board is divided into distinct functional regions: a first region for mounting the switching element and a second region for mounting the electronic component. This segmentation physically separates heat-generating components from heat-sensitive components on the same board, allowing simplified mounting while protecting against thermal interference through spatial zoning

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the circuit board are assigned different functional qualities - the first region accommodates high-heat switching elements while the second region provides a thermally favorable environment for heat-sensitive electronic components. This local differentiation allows both components to coexist on the same board without compromising either thermal management or device simplicity

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

This arrangement effectively manages heat without increasing the tool's length, ensuring efficient operation and compactness while minimizing heat-related protection measures for electronic components.

Implementation Method 1

with a heat radiation or insulation material applied to prevent heat transfer

Methodology Applied

Scientific EffectHeat radiation: Thermal Radiation

Implementation Method 2

with a heat radiation or insulation material applied to prevent heat transfer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS9621009B2Electric power tool including a plurality of circuit boards

Publication Date: 2017.04.11 MAKITA CORP

AI summary

An electric power tool, which uses a DC brushless motor as a drive source and controls the DC brushless motor by a switching element, can include a tubular housing main body portion accommodating the DC brushless motor, and a grip portion protruding from a side portion of the housing main body portion. The switching element is arranged inside the grip portion, and is spaced apart from an electronic circuit board for an electronic component for operating the switching element.