Portable Electric Cutter Fan Cooling for Motor and Circuit Board
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Solution Overview
Problem
Portable electric round saws with high power motors face challenges in securing and cooling circuit boards without compromising operability or significantly altering the housing shape, especially when using brushless motors.
Innovation Solution
The design incorporates a centrifugal fan to cool both the motor and circuit board, utilizing slit-like cooling air vents and a fan guide to efficiently direct airflow, while positioning the circuit board between the handle and base to minimize space requirements and maintain operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a brushless motor is adopted for high power and efficiency, then motor performance is improved, but the volume required for the circuit board and heat dissipation increases
Solution Approach 1:
The circuit board is integrated into the handle structure, merging two previously separate components (circuit board housing and handle) into one unified structure. This eliminates the need for separate housing space and reduces overall volume requirements.
Solution Approach 2:
The circuit board is positioned in a three-dimensional space within the handle, utilizing vertical and lateral dimensions rather than only linear extension. This allows efficient space utilization within the confined handle volume.
2Adaptability or versatility
If a circuit board is added to drive the brushless motor, then motor control capability is improved, but the housing volume increases
Solution Approach 1:
The circuit board housing is merged with the handle structure, creating a unified component that serves dual purposes: housing the circuit board and forming part of the tool's handle. This eliminates redundant housing volume.
Solution Approach 2:
The handle structure is given multiple functions: it serves as both the gripping handle and the housing for the circuit board. This multi-functionality reduces the need for separate dedicated housing space.
3Temperature
If cooling measures are implemented for the circuit board, then heat dissipation is improved, but the housing shape is significantly altered
Solution Approach 1:
Cooling air vents are strategically positioned at specific locations on the handle (front surface and rear surface) rather than requiring overall housing shape changes. This localized approach maintains the general housing form while providing effective cooling pathways.
Solution Approach 2:
The fan mounted on the motor shaft provides cooling for both the motor and the circuit board simultaneously. The rotating fan blades draw air through the cooling vents and direct it over the circuit board, eliminating the need for a separate cooling system.
4Volume of stationary object
If the circuit board is positioned to minimize space, then space efficiency is improved, but operability may be impaired
Solution Approach 1:
The circuit board is positioned in a specific region of the handle (integrated into the handle structure) that does not interfere with the user's grip or operation. This localized positioning maintains operability while achieving space efficiency.
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 secures space for the circuit board and cools it without impairing the saw's operability or altering the housing shape significantly, ensuring efficient cooling of both the motor and circuit board components.
Implementation Method 1
a centrifugal fan 7 fixed to an output shaft 1a of the motor 1
Implementation Method 2
cooling the motor 1 by fan air generated by the rotation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A portable electric cutter includes a housing 2 in which a motor 1 is accommodated, a saw blade driven to rotate by the motor, a base 6 coupled to the housing 2 and having a bottom surface slidable on a surface of a material to be cut, a fan 7 driven to rotate by the motor, a driving circuit for switching power supplied to the motor, and a control circuit for controlling the driving circuit. A circuit board 60 on which the driving circuit, the control circuit and others are mounted is provided, motor cooling air vents are provided in the housing 2 on a side opposite to the saw blade, and circuit board cooling air vents are provided in the housing 2 on the side opposite to the saw blade.