Fan Electromagnetic Shielding Structure for EMC Compliance
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Solution Overview
Problem
Conventional cooling fans emit significant electromagnetic radiation that interferes with surrounding sensitive electronic elements or devices, failing to meet electromagnetic compatibility (EMC) test standards, particularly in the high frequency band ranging from 30 MHz to 1 GHz.
Innovation Solution
The fan design incorporates a metal hub and metal carrier that form a shielding space to enclose the stator and circuit board, preventing electromagnetic radiation from leaking out by isolating the stator structure and electronic elements within this space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional fan structure with stator and circuit board is used, then cooling function is achieved, but electromagnetic radiation leaks out and interferes with surrounding electronic elements
Solution Approach 1:
The patent applies nesting by placing the stator and circuit board inside a shielding cavity formed by the metal hub and metal carrier. The metal hub contains a receiving space that accommodates the stator, while the metal carrier provides additional shielding and support. This nested structure effectively contains electromagnetic radiation within the fan housing, preventing leakage to surrounding electronic elements while maintaining a compact design.
Solution Approach 2:
The patent introduces a metal carrier as an intermediary component between the stator and the external environment. This metal carrier acts as a shield that blocks electromagnetic radiation from the stator and circuit board, preventing it from leaking out. The intermediary shielding structure resolves the contradiction by adding a targeted component rather than redesigning the entire fan system.
2Reliability
If shielding structure is added to prevent electromagnetic radiation, then EMC test standards are met, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by designing the metal hub to serve both as the rotating component driving the fan blades and as part of the electromagnetic shielding structure. The metal carrier similarly provides both structural support and shielding functions. This approach ensures EMC compliance without adding separate dedicated shielding components, thereby avoiding excessive complexity increase.
Solution Approach 2:
The patent merges the shielding function with existing structural components. The metal hub and metal carrier are integrated into the fan's mechanical structure, combining electromagnetic shielding with structural support and rotation functions. This merging approach ensures that the shielding structure becomes an inherent part of the fan design rather than an add-on, minimizing the impact on overall device complexity.
3Object-affected harmful factors
If metal hub and metal carrier are used for shielding, then electromagnetic radiation is contained, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes the inherent electrical conductivity parameter of metal materials to achieve electromagnetic shielding. By selecting metal hub and metal carrier materials with appropriate conductivity properties, the design effectively contains electromagnetic radiation without requiring complex composite materials or specialized manufacturing processes. This parameter-based approach simplifies manufacturing while maintaining shielding effectiveness.
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
The redesigned fan effectively prevents electromagnetic radiation from escaping, meeting EMC test standards by ensuring electromagnetic waves remain contained, thus avoiding interference with nearby electronic components.
Implementation Method 1
The fan design incorporates a metal hub and metal carrier that form a shielding space to enclose the stator and circuit board, preventing electromagnetic radiation from leaking out by isolating the stator structure and electronic elements within this space.
Data Source
AI summary
A fan with electromagnetic radiation shielding structure includes a fan impeller and a shaft seat. The fan impeller includes a metal hub, a plurality of blades circumferentially spaced on an outer surface of the metal hub, and a magnetic element provided on an inner surface of the metal hub. The shaft seat is provided at a central area with an upward projected shaft barrel, which is rotatably connected to the fan impeller and has a stator externally fitted therearound. A metal carrier is provided on the shaft seat and has a peripheral edge extended upward to form a sidewall and define an open-topped receiving space for receiving the stator therein. The metal hub and the metal carrier together define a shielding space, such that the stator is located in the shielding space and isolated from outer environment to avoid leakage of electromagnetic radiation produced by the stator.