Partial Ring Cooling Fan Design for Centrifugal Stress Reduction
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Solution Overview
Problem
Molded plastic cooling fans with full 360° rings face weaknesses due to knit lines and increased stress from centrifugal forces at higher rotational speeds, leading to potential failure and reduced airflow capacity.
Innovation Solution
A partial circumferential ring design connected to the blade tips, which is lighter and more robust, allowing for improved airflow and reduced noise while maintaining structural integrity by minimizing material usage and balancing forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a full 360° ring is used to provide stability and reduce vortex shedding, then structural strength and vibration characteristics improve, but weight increases and centrifugal forces at the blade-ring interface cause failure in molded plastic fans
Solution Approach 1:
The patent divides the continuous 360° ring into multiple discrete ring segments positioned at specific locations around the fan perimeter. This segmentation reduces the total material required and weight, while still providing the structural benefits at critical positions. The segments are strategically placed to maintain stability and reduce vortex shedding without requiring a complete circumferential ring.
Solution Approach 2:
The patent applies ring structures only at specific locations where they are most needed for structural support and vortex reduction, rather than uniformly around the entire circumference. This localized application optimizes the balance between structural strength and weight reduction, placing rings only where they provide maximum benefit.
2Productivity
If fan rotational speed is increased to meet cooling demands, then air flow capacity improves, but centrifugal forces at the blade-ring interface increase causing failure
Solution Approach 1:
By segmenting the ring structure, the patent reduces the total mass at the blade-ring interface, thereby reducing centrifugal forces during high-speed rotation. The segmented design maintains structural integrity while minimizing the inertial loads that cause failure at elevated rotational speeds.
Solution Approach 2:
The patent uses partial rings rather than complete 360° rings, providing just enough structural support and vortex control where needed without the excessive mass that would generate problematic centrifugal forces at high speeds.
3Ease of manufacture
If molded plastic construction is used to reduce weight and simplify manufacturing, then ease of manufacture improves, but knit lines create weak points in the ring structure
Solution Approach 1:
The segmented ring design allows each segment to be molded independently, avoiding the knit lines that occur when molding continuous rings. This segmentation enables simpler molding processes for each individual segment while maintaining overall structural strength through the distributed arrangement of segments around the fan perimeter.
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 partial ring design enhances airflow efficiency and static pressure, reduces torque requirements, and maintains noise levels comparable to full ring fans, while minimizing material usage and weight, thus improving fan performance and durability.
Implementation Method 1
The ring provides stability to the blade tips and also helps reduce vortex shedding at the blade tips
Implementation Method 2
the centrifugal force exerted on the blade-ring interface caused by the mass inertia of the complete circumferential ring at increased fan speeds
Data Source
AI summary
A cooling fan with partial ring members attached to the blade tips. The fan preferably is a one-piece molded fan with a central hub and a plurality of blade members. Partial ring members on the blade tips reduce weight and minimize potential failures caused by knit lines and operations at high rotational speeds.