Cooling Fan Stator Grounding for EMI Shielding and ESD Protection
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Solution Overview
Problem
Cooling fans used in electronic devices and automobiles generate electromagnetic interference that can damage circuit components and increase manufacturing costs due to the need for separate EMI blocking filters.
Innovation Solution
A cooling fan design where the stator core is directly electrically connected to the ground of a printed circuit board, expanding the ground area and improving EMI blocking performance by using a ring-shaped connection hole in the stator core for a joint pin to connect with the PCB, allowing for enhanced static electricity protection and simplified assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a separate filter unit is provided to block electromagnetic waves, then EMI blocking performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the EMI blocking function with the stator core structure by directly electrically connecting the stator core to the ground pattern of the PCB through a joint pin. This integration eliminates the need for a separate filter unit, thereby reducing device complexity while maintaining EMI blocking performance.
Solution Approach 2:
The stator core is given multiple functions: it serves both as the magnetic circuit component of the motor and as the EMI blocking structure. By electrically connecting the stator core to ground, it simultaneously performs its motor function and provides electromagnetic interference shielding, reducing the need for additional components.
2Object-affected harmful factors
If a separate filter unit is provided to block electromagnetic waves, then EMI blocking performance is improved, but manufacturing cost increases
Solution Approach 1:
The EMI blocking function is merged into the existing stator core and PCB assembly process. The joint pin connects the stator core to the ground pattern during normal assembly, eliminating the need to manufacture and install separate filter units, thereby reducing manufacturing cost.
Solution Approach 2:
The stator core serves dual purposes as both a motor component and an EMI shielding element. This multi-functionality eliminates the need for additional filter components, reducing part count and manufacturing cost while maintaining EMI blocking performance.
3Object-affected harmful factors
If ground area is expanded by direct electrical connection of stator core to PCB, then EMI blocking performance is improved, but stator core structure complexity increases
Solution Approach 1:
The joint pin serves as an intermediary element that simply connects the stator core to the ground pattern on the PCB. This straightforward connection method expands the ground area and improves EMI blocking without requiring complex modifications to the stator core structure itself.
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 design effectively prevents damage from static electricity and enhances EMI shielding performance, reducing the risk of electromagnetic interference and simplifying the manufacturing process by expanding the ground area and improving EMI blocking without the need for additional filters.
Implementation Method 1
a joint pin inserted into the connection hole portion to electrically connect the stator core to the PCB
Implementation Method 2
improving electromagnetic interference (EMI) blocking performance by directly electrically connecting a stator core made of metal to the ground of a printed circuit board (PCB) to expand an area of the ground
Data Source
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AI summary
A cooling fan includes: a rotary shaft which is rotatably supported in a fan housing; a rotor which is fixed to the rotary shaft; a stator which is fixed to the fan housing, is arranged so as to be arranged at a predetermined gap away from the rotor, and includes a plurality of stacked stator cores on which a coil is wound; an impeller which is connected to the rotor; a printed circuit board (PCB) which is installed on the bottom side of the stator and controls the cooling fan; and a ground portion which is installed on the stator cores, is electrically connected to a ground pattern of the PCB and expands a ground surface. Thus, damage of circuit components due to electrostatic electricity is prevented, and EMI shielding properties are improved.