Brushless Motor Control Board Cooling via Aluminum Housing
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Solution Overview
Problem
Conventional electric power tools lack a mechanism to cool the motor control circuit, particularly when using brushless motors, which generates heat due to the inverter circuit's switching elements, leading to reduced durability and performance.
Innovation Solution
The electric power tool incorporates a motor housing made of aluminum alloy that exposes the control board with the motor control circuit adjacent to it, allowing heat dissipation through the motor housing, thereby improving cooling characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a brushless motor with inverter circuit is used to control motor rotation, then motor control precision is improved, but heat generation from switching elements increases causing reduced reliability
Solution Approach 1:
The control board is extracted from the motor housing interior and disposed outside the motor housing. This separates the heat-generating control circuit from the motor components, allowing independent cooling of the control board while maintaining motor control precision. The switching elements on the control board are no longer constrained by the motor housing's thermal environment.
Solution Approach 2:
A heat dissipation plate is introduced as an intermediary between the control board and the external environment. The heat dissipation plate receives heat from the switching elements on the control board and facilitates thermal transfer to the surrounding air or cooling system, effectively managing the heat generated by the inverter circuit while preserving control circuit reliability.
2Device complexity
If control board is disposed inside motor housing, then device structure is simplified, but cooling characteristics of control circuit deteriorate
Solution Approach 1:
The control board is extracted from the motor housing interior and disposed outside the motor housing. This separation allows the control board to be cooled by external air flow while maintaining a relatively simple overall structure. The motor housing continues to serve its primary function of housing the motor, while the control board operates in a separate, cooler environment.
Solution Approach 2:
The heat dissipation plate serves multiple functions: it provides thermal management for the control board, acts as a mounting surface for the control board, and facilitates heat transfer to the surrounding environment. This multi-functional component reduces the need for additional specialized cooling structures, maintaining structural simplicity while improving cooling characteristics.
3Ease of operation
If switching elements perform current control operation, then motor rotation control is improved, but heat generation increases requiring cooling mechanism
Solution Approach 1:
A heat dissipation plate is introduced as a thermal intermediary between the switching elements and the external environment. The heat dissipation plate efficiently captures heat from the switching elements during current control operations and transfers it to the surrounding air or cooling system, managing thermal energy loss while preserving motor control capability.
Solution Approach 2:
The control board with switching elements is extracted from the motor housing and disposed outside, where it can be cooled by external air flow. This extraction allows the switching elements to perform current control operations with improved heat dissipation, reducing thermal energy loss while maintaining ease of motor control 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 configuration enhances the heat dissipation of the motor control circuit, improving the durability and performance of the brushless motor by effectively managing heat generated by the switching elements.
Implementation Method 1
heat from the electronic component is transmitted to the motor housing having a heat dissipation property
Implementation Method 2
motor housing being exposed to an exterior portion
Data Source
AI summary
An electric power tool has a brushless motor for driving a tip tool, and a motor case is at least partly covered by a motor housing made of aluminum alloy and exposed to an outside. A control board provided with a control circuit for controlling the rotation of the brushless motor is disposed adjacent to the motor housing. The brushless motor and a control board are cooled by cooling air generated by a fun, thereby enhancing the cooling characteristics of the motor control circuit.