Propeller Fan Blade Root Strength via Multi-Gate Injection
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Solution Overview
Problem
Propeller fans manufactured by injection molding with fiber-reinforced plastic (FRP) often experience blade root breakage due to the orientation of continuous fibers parallel to the flow direction, leading to reduced strength and potential failure at low revolution numbers.
Innovation Solution
The propeller fan design incorporates multiple injection positions for the resin material around the root portion of each blade, dispersing gates in the circumferential direction to regulate the resin flow perpendicular to the blade's width, ensuring the continuous fibers are oriented perpendicularly, enhancing the root's strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single injection position is used for the blade root portion, then the manufacturing process is simple, but the fiber orientation becomes parallel to the flow direction causing reduced strength
Solution Approach 1:
The injection system is segmented into multiple injection positions (first injection position and second injection position) around the blade root portion. This segmentation allows independent control of resin flow directions, enabling fibers to orient perpendicular to the blade width direction, thereby significantly improving blade root strength while maintaining manufacturing feasibility
Solution Approach 2:
Different injection positions are strategically placed to create specific local fiber orientations in different regions of the blade root. The first injection position targets one region while the second injection position targets another region, ensuring that fibers in each local area are oriented perpendicular to the blade width direction, optimizing strength where most needed
2Reliability
If multiple injection positions are used around the blade root, then fiber orientation is improved perpendicular to blade width, but the molding process becomes more complex
Solution Approach 1:
The molding process is segmented into multiple injection phases with distinct positions. The first injection position injects resin to establish initial fiber orientation, while the second injection position supplements the resin flow to reinforce perpendicular fiber alignment. This segmented approach improves durability while keeping each injection phase relatively simple and controllable
Solution Approach 2:
The first injection position performs preliminary action by establishing the primary resin flow pattern and initial fiber orientation before the second injection position adds supplementary resin. This preliminary action ensures that fibers are already oriented favorably before additional resin is introduced, reducing the need for complex post-processing
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 significantly improves the root portion's strength and durability, allowing the propeller fan to operate at higher revolution numbers without blade breakage, as the fiber orientation perpendicular to the root's width direction mitigates cracking and enhances structural integrity.
Implementation Method 1
a flow direction of the resin material containing the continuous fiber is regulated by the flow of the resin material from the injection positions adjacent to each other, and is in a direction perpendicular to a width direction of the root portion of the blade
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A propeller fan molded by injection molding using a resin material containing a continuous fiber, includes a hub having an end surface wall and a peripheral wall; and a plurality of blades on an outer periphery of the hub, the propeller fan being molded by providing a plurality of injection positions for injecting the resin material containing the continuous fiber in a part of the end surface wall corresponding to a root portion of one of the blades of the hub.