Propeller Fan Hub Blade Segmentation to Reduce Weight and Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Propeller fans used in air conditioners have a large and heavy hub that increases manufacturing costs and can lead to increased noise and flow resistance when blade angles are increased for higher airflow, due to stress concentration and flow separation issues.
Innovation Solution
A propeller fan design with a lightweight and rigid hub structure, featuring spirally extending hub blades, recesses on the blades to reduce thickness, and vortex generators on the blade surfaces to manage stress and flow resistance, allowing for higher blade angles without increased noise or flow separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hub size is increased to support the propeller fan blades at high speed, then the rigidity and structural stability are improved, but the overall weight and manufacturing costs increase
Solution Approach 1:
The hub is divided into multiple hub blades (typically 3-5) that extend spirally from the hub body. Each hub blade acts as an independent structural element that provides support and rigidity. This segmentation allows the hub to achieve the necessary mechanical strength while using less material compared to a solid cylindrical hub, thereby reducing weight and manufacturing costs.
2Productivity
If the blade angle is increased to increase airflow volume, then the air moving capability is improved, but flow resistance and noise increase due to flow separation
Solution Approach 1:
The hub blades are designed with a spiral curvature that extends from the hub body toward the blades. This curved geometry guides the airflow smoothly along the blade surfaces, preventing flow separation even at higher blade angles. The spiral shape of hub blades creates a more gradual pressure gradient, reducing turbulence and noise while maintaining high airflow volume capability.
3Productivity
If the blade angle is increased to increase airflow volume, then the air moving capability is improved, but stress concentration occurs between blades and hub
Solution Approach 1:
The spiral-shaped hub blades create a gradual transition zone between the hub body and the main blades. This curved geometry distributes the mechanical stress more evenly across the connection interface, preventing stress concentration that would occur with abrupt angular connections. The spiral shape allows for smoother load transfer during rotation, enhancing structural integrity at higher blade angles.
4Stability of the object's composition
If a traditional large hub is used to support the blades, then structural stability is improved, but the device complexity and manufacturing costs increase
Solution Approach 1:
The hub structure is segmented into a hub body and multiple hub blades, where the hub blades serve dual purposes: structural support and airflow guidance. This segmentation replaces the need for a large, complex solid hub with a simpler, more elegant solution that achieves the same structural stability through distributed support elements. The segmented design is also easier to manufacture using conventional molding techniques.
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 design results in a propeller fan that is lightweight, cost-effective, with improved airflow performance and reduced noise, enabling higher airflow volumes while maintaining structural integrity and reducing overall volume.
Implementation Method 1
vortex generators on the blade surfaces to manage stress and flow resistance
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A propeller fan that includes a hub body with a shaft coupling portion. The propeller fan also includes a plurality of hub blades extending spirally from the hub body. The propeller fan additionally includes a plurality of blades extending outward from the hub body and the hub blade to generate an airflow in an axial direction.