One-Piece Axial Fan Impeller Molding to Reduce Air Turbulence
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Solution Overview
Problem
Existing axial fans in heat exchangers of heat pumps face challenges with increased manufacturing costs, turbulence, and noise due to separate blade-hub connections, leading to reduced efficiency and flow resistance.
Innovation Solution
The impeller blades and hub are formed in one piece from fiber-reinforced synthetic material by injection molding, with a thickened connection seam to reduce turbulence and noise, and reinforced geometries to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blades are made separately from hub and connected together, then manufacturing flexibility and material selection are improved, but manufacturing costs and assembly complexity increase
Solution Approach 1:
The patent merges the hub and blades into a single integrated impeller component manufactured by injection molding. This eliminates the need for separate manufacturing and assembly operations, reducing both manufacturing complexity and assembly steps while maintaining the ability to optimize material selection for the entire impeller structure.
2Adaptability or versatility
If blades are made separately from hub and connected together, then manufacturing flexibility is improved, but manufacturing costs increase
Solution Approach 1:
The hub and blades are combined into a single injection-molded component, eliminating multiple manufacturing processes, material handling, and assembly operations. This integration significantly reduces manufacturing costs despite maintaining flexibility in material and design selection.
3Ease of manufacture
If conventional blade connection to hub is used, then manufacturing simplicity is maintained, but air turbulence and noise increase
Solution Approach 1:
By merging the hub and blades into a single monolithic injection-molded component, the patent eliminates connection seams and joints that generate turbulence. The seamless integration ensures smooth airflow passage while maintaining manufacturing simplicity through the injection molding process.
Solution Approach 2:
The injection molding process allows for local optimization of the blade root geometry where it connects to the hub, creating smooth transitions and avoiding sharp edges or discontinuities that would generate turbulence. The local quality of the root portion is specifically optimized for fluid dynamic performance.
4Ease of manufacture
If conventional blade connection to hub is used, then manufacturing simplicity is maintained, but conveying efficiency decreases
Solution Approach 1:
The integrated hub-blade structure eliminates connection interfaces that cause flow separation and turbulence, thereby improving air conveying efficiency. The seamless geometry ensures optimal airflow guidance while the injection molding process maintains manufacturing simplicity.
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
This design simplifies manufacturing, reduces costs, and improves efficiency and noise levels by minimizing air turbulence and enhancing airflow directionality.
Implementation Method 1
the blades (7) and the side wall (5) of the hub (3) are formed in one piece from fiber-reinforced synthetic material by injection molding
Implementation Method 2
considerable turbulence in the impellers of the axial fans of the prior art is observable at the roots of the blades, in particular in the regions between the roots of two consecutive blades, respectively. This turbulence reduces the conveying efficiency
Implementation Method 3
The shape of the individual blades of the impeller is conventionally curved, in both the radial direction, i.e., in section according to planes which are radial to the rotation axis of the fan, and the circumferential direction, i.e., in section according to planes which are tangent to circumferences with respect to the rotation axis of the fan, in order to direct the air flow along the blades, minimizing the generation of turbulence
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An impeller (2) for an axial fan (1) comprises a hub (3) having a side wall (5) being circumferential with respect to a rotation axis (6) of the impeller (2), a plurality of blades (7) protruding from the side wall (5) with a front edge (12), a rear edge (13) and a peripheral edge (21), wherein a rotation of the impeller (2) generates an air flow in the direction of the rotation axis (6) from a suction side (8) towards a delivery side (9) of the impeller (2), wherein a root portion (10) of the blade (7) creates the connection between the blade (7) and the side wall (5) and forms a connection seam (11) which locally thickens the root (10) with respect to the thickness of the blade (7) adjacent to the root (10), and which extends all about the blade (7), and/or wherein the blades (7) and the side wall (5) of the hub (3) are formed in one piece from fiber-reinforced synthetic material by injection molding.