COB LED Light Unit Insulation Around a Power Tool Output Shaft

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Solution Overview

Problem

Chip-on-board light emitting diodes (COB LEDs) in power tools experience excessive temperature rise due to heat inflow from other sources, leading to potential deterioration and reduced lifespan.

Innovation Solution

Incorporating a heat insulating material around the COB LED to suppress its temperature to a predetermined allowable value, which can include positioning the heat insulating material between heating sources and the LED, or using a heat insulating sheet to prevent heat transfer from the gear case to the LED.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a chip-on-board light emitting diode is used to emit higher amount of light, then illumination intensity is improved, but temperature rises excessively due to heat inflow from other heat sources

Engineering Contradiction:

Improvelight outputVSAvoidCOB LED temperature

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

A heat insulating material is introduced as an intermediary between the COB LED and heat sources (motor, gear case). This mediator blocks heat transfer from these components to the LED, allowing the LED to maintain high illumination output while operating at acceptable temperatures. The heat insulating material acts as a thermal barrier that protects the sensitive LED from external heat without affecting its light-emitting function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If the COB LED operates at high temperature, then light output may be maintained, but the lifespan of the COB LED is shortened and deterioration occurs

Engineering Contradiction:

Improvelight outputVSAvoidCOB LED lifespan

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The heat insulating material serves as a protective intermediary that isolates the COB LED from heat sources, creating a thermal buffer zone. This allows the LED to maintain its light output performance while the insulating material absorbs or blocks external heat, thereby preserving the LED's lifespan and preventing thermal deterioration.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The heat insulating material is positioned in advance around the COB LED to prevent heat accumulation before it can cause damage. By providing thermal insulation beforehand, the system cushions the LED against temperature rises that would otherwise lead to deterioration and reduced lifespan, ensuring long-term reliable operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

Effectively prevents excessive temperature rise, thereby extending the lifespan of the COB LED and maintaining its performance by ensuring it operates within a safe temperature range.

Implementation Method 1

Methodology Applied

Scientific EffectThermal Insulation: Thermal Insulation

Data Source

PatentUS11913633B2Power tool, light unit, and floodlight

Publication Date: 2024.02.27 MAKITA CORP

AI summary

A power tool includes: a motor; an output shaft that is rotated by a rotational force of the motor; a chip-on-board light emitting diode disposed around the output shaft; and a suppression device configured to suppress a temperature of the chip-on-board light emitting diode to a predetermined allowable value or less.