Centrifugal Fan Resin Casing Ribs Vibration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional centrifugal fans face challenges in weight reduction and vibration control due to the use of metallic lower casings, which require high processing accuracy and increase weight, while resin-formed yokes suffer from stiffness issues and vibration problems when thickness is reduced.
Innovation Solution
A centrifugal fan design featuring resin upper and lower casings with radial and circumferential ribs, resin pins for fixing the circuit board, and a hollow cylindrical bearing holder to reduce weight and enhance stiffness, thereby minimizing vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic lower casing is used to ensure structural strength, then the centrifugal fan achieves sufficient stiffness, but the weight increases and processing costs rise
Solution Approach 1:
The patent changes the material parameter from metal to resin, and compensates for the lower inherent strength by modifying the geometric parameter - adding ribs to increase structural stiffness. This allows weight reduction while maintaining sufficient mechanical strength through shape optimization rather than material selection.
Solution Approach 2:
The patent creates a composite structure by combining resin material with rib reinforcements. The ribs act as structural strengtheners within the resin casing, creating a composite system that achieves metal-like stiffness with resin-like light weight, resolving the contradiction between strength and weight.
2Weight of moving object
If the lower casing is made from resin to reduce weight, then the centrifugal fan becomes lighter, but the stiffness deteriorates causing vibration
Solution Approach 1:
The patent segments the lower casing by adding ribs that divide the continuous resin structure into reinforced zones. These ribs create a segmented framework within the resin casing, providing localized stiffness enhancement that prevents vibration while maintaining overall light weight.
Solution Approach 2:
The patent addresses the two-dimensional weakness of thin resin casings by adding a third dimensional element - ribs extending in the axial direction. This dimensional addition creates out-of-plane support that dramatically increases stiffness without significantly increasing weight, preventing vibration issues.
3Weight of moving object
If the yoke thickness is reduced to achieve weight reduction, then the fan becomes lighter, but the natural frequency decreases causing vibration
Solution Approach 1:
The patent changes the geometric parameter of the yoke by adding ribs that increase the moment of inertia without significantly increasing mass. This parameter modification raises the natural frequency of the yoke structure, preventing vibration while maintaining weight reduction goals.
4Strength
If a metallic lower casing is used, then structural strength is ensured, but processing costs increase due to high accuracy requirements
Solution Approach 1:
The patent replaces expensive metal machining with cheaper resin molding. Resin casting allows for complex rib structures to be formed directly in the mold without expensive multi-step machining operations, significantly reducing processing costs while maintaining structural strength through the rib reinforcement design.
Solution Approach 2:
The patent changes the manufacturing parameter from precision machining (metal) to mold-based forming (resin). This parameter change enables complex reinforced structures to be produced more economically, as the ribs are formed as integral parts of the molded casing rather than requiring separate fabrication and assembly steps.
Data Source
AI summary
A centrifugal fan that is light in weight and has a structure that restrains vibration are provided. The centrifugal fan includes a resin upper casing, a resin lower casing, an impeller, a motor, and a circuit board. The impeller, the motor and the circuit board are housed between the resin upper casing and the resin lower casing. Radial ribs and a concentric ribs for reinforcing are formed at a bottom surface of a concave part of the lower casing. Resin pins are provided in a standing manner at these rib parts, and the circuit board is fixed to the lower casing by the resin pins.