High-Emissivity Heat Sink for Power Tool Thermal Management
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Solution Overview
Problem
Power tools with brushless direct current motors experience heat-related issues due to insufficient air circulation from fans, leading to potential shutdowns, especially in tools like roofing nailers that operate intermittently and generate excessive heat.
Innovation Solution
Incorporating a heat sink with a high emissivity material, such as anodized aluminum, to enhance heat dissipation from field effect transistors (FETs) in the power switching network, which increases the heat absorption and dissipation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a fan is used to generate cooling air flow, then heat dissipation is improved, but the cooling effect is insufficient for intermittent operation tools
Solution Approach 1:
The patent changes the physical parameter of the heat sink surface by applying a high-emissivity coating (anodization) to increase radiative heat transfer capability. This transforms the thermal radiation parameter from standard emissivity to high emissivity, enabling effective heat dissipation during intermittent operation when fan cooling is insufficient.
2Productivity
If the motor runs for limited time during actuation, then the tool can complete fast operations, but heat accumulates faster than the fan can dissipate
Solution Approach 1:
The patent introduces a high-emissivity coating as an intermediary layer between the heat-generating FETs and the environment. This coating acts as a thermal radiation mediator that enhances the heat transfer from the power switching network to the surrounding air, complementing the fan cooling system and enabling sustained high-speed actuations.
3Temperature
If a standard heat sink is used, then heat dissipation is provided, but the tool still shuts down at high temperatures
Solution Approach 1:
The patent modifies the thermal radiation parameter of the heat sink by applying an anodized coating with high emissivity properties. This parameter change increases the radiative heat transfer coefficient, enabling the heat sink to dissipate heat more effectively and prevent tool shutdown during prolonged or intermittent high-load operation.
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 solution effectively prevents tool shutdowns from overheating, allowing for a significant increase in the number of actuations before thermal failure, even in high-temperature conditions.
Implementation Method 1
The heat sink includes a high emissivity material having an emissivity of greater than or equal to 0.1
Implementation Method 2
A heat sink is in a heat-transfer relationship with the plurality of switches
Data Source
AI summary
Power tool (10) with high emissivity heat sinks (66). One embodiment provides a power tool (10) including a power source, a motor (46), and a power switching network (58) coupled between the power source and the motor (46). The power switching network (58) includes a plurality of switches (62). A heat sink (66) is in a heat-transfer relationship with the plurality of switches (62). The heat sink (66) includes a high emissivity material having an emissivity of greater than or equal to 0.1 and/or a high emissivity finish to increase the emissivity of the heat sink.