Inner-Rotor Fan Assembly With PCB Cooling and High-Speed Stability
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Solution Overview
Problem
Conventional inner-rotor fan devices face issues with heat dissipation due to lack of space between the impeller and stator, instability at high rotational speeds, and complex assembly requiring additional fasteners and manual labor for circuit board alignment.
Innovation Solution
The fan device incorporates a frame with an accommodating groove and cover design for airflow heat dissipation, riveted or embedded assemblies for stability, and automated circuit board assembly using pin headers and guide ribs for reduced size and improved space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the magnetic ring is fixed on the impeller in a conventional inner-rotor fan device, then the structure is simplified, but there is no space between the impeller and the winding set of the stator for airflow to dissipate heat, affecting operational stability
Solution Approach 1:
The impeller is divided into two parts: an impeller body and a cover. The cover is detachably connected to the impeller body, creating a segmented structure. This segmentation allows the cover to function as a heat dissipation component while maintaining the simplified magnetic ring fixation structure, thus resolving the contradiction between structural simplicity and operational stability.
Solution Approach 2:
The cover is designed to be disposed on the impeller body, forming a nested structure where the cover surrounds part of the impeller body. This nesting creates an air passage between the cover and the impeller body, enabling heat dissipation airflow while maintaining a compact overall structure.
2Ease of manufacture
If assembly fit (sliding fit) with a buckle is used to fix the axial position of the impeller, then assembly is achieved, but the fan device cannot meet stability requirements at high rotational speeds
Solution Approach 1:
The cover is preliminarily disposed on the impeller body to form a fixed structure before high-speed operation. This preliminary structural arrangement ensures that the impeller components are securely positioned, providing the necessary stability for high-speed rotation while maintaining ease of assembly through the detachable connection design.
3Manufacturing precision
If two printed circuit boards are used with additional fasteners to match holes or notches, then assembly effect is achieved, but additional assembly man-hours are required and automated assembly needs are not met
Solution Approach 1:
The cover is designed with self-positioning features including a positioning protrusion on the cover that fits into a positioning groove on the impeller body. This self-service positioning mechanism eliminates the need for additional fasteners and complex hole-matching operations, enabling automated assembly while maintaining precise positioning of components.
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
Enhances operational stability through effective heat dissipation and high-speed operation, reduces assembly time, and allows for automated assembly of multiple circuit boards.
Implementation Method 1
the airflow can flow into the accommodating groove through the opening to dissipate heat from the circuit board disposed in the accommodating groove
Implementation Method 2
The impeller has a plurality of heat dissipation holes. The heat dissipation holes communicate an inner side and an outer side of the impeller
Data Source
AI summary
A fan device includes a motor set, an impeller, a frame, and a circuit board. The impeller is rotatably connected to one end of the motor set. The frame is disposed at another end of the motor set. The frame includes a wall portion. The wall portion surrounds to form an accommodating groove. The wall portion has a through hole. The circuit board is accommodated in the accommodating groove.