Integrally Molded Impeller Hub Concentricity Control
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Solution Overview
Problem
Conventional plastic impellers require multiple secondary operations and bonding processes that lead to concentricity issues, resulting in vibration, bearing damage, and reduced mechanical efficiency due to clearance problems during high-speed rotation and pumping.
Innovation Solution
A single-piece molded impeller design with critical concentricity features, where the impeller vanes, motor hub, nose, and eye are integrally molded, and a second piece with a cover is ultrasonically welded around the motor hub, reducing the need for machining and improving concentricity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional bonding processes are used to assemble impeller pieces, then the impeller can be manufactured in multiple parts, but concentricity between the hub and nose deteriorates due to fixture clearances and alignment issues
Solution Approach 1:
The patent combines the hub and nose into a single integrally molded piece, eliminating the need for secondary bonding operations. This merging of previously separate components (first piece with hub and second piece with nose) into one monolithic structure ensures perfect concentricity while maintaining manufacturability through injection molding capabilities.
Solution Approach 2:
The impeller is segmented into two functional parts: an integrally molded first piece containing the hub, vanes, and nose, and a separate cover piece. This segmentation allows the critical concentricity features (hub and nose) to be manufactured together as one precision component, while the cover can be separately molded and attached, balancing manufacturability with precision requirements.
2Manufacturing precision
If additional clearances are machined into the fit between nose and wear ring, then concentricity issues are corrected, but internal leakage increases reducing mechanical efficiency
Solution Approach 1:
By merging the hub and nose into a single integrally molded piece, the patent eliminates concentricity errors at the source, removing the need for compensating clearances. This allows the nose to fit tightly against the wear ring without risking misalignment, thereby minimizing internal leakage and energy loss during pumping operations.
3Ease of manufacture
If conventional bonding processes with fixtures are used, then parts can be assembled, but vibration and noise increase during high-speed rotation due to clearance room
Solution Approach 1:
The integration of hub and nose into one piece eliminates clearance-induced vibration and noise. The single-piece construction ensures rigid, stable rotation at high speeds without the harmful vibrations that plague multi-part assemblies with clearance gaps.
4Ease of manufacture
If multiple secondary operations are performed on conventional impellers, then complete impeller assembly is achieved, but manufacturing time and complexity increase
Solution Approach 1:
The patent merges the manufacturing of hub and nose into a single injection molding operation, eliminating at least two secondary operations (bonding and machining) required by conventional multi-part impellers. This significantly reduces manufacturing time and complexity while achieving complete impeller assembly.
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 approach minimizes internal leakage, reduces noise and bearing wear, and enhances mechanical efficiency by maintaining precise concentricity and alignment, leading to improved pump performance and reduced manufacturing costs.
Implementation Method 1
coupling the first piece to the second piece by ultrasonic welding the cover to the impeller vanes around the motor hub
Data Source
AI summary
Embodiments of the invention provide an impeller and a method of producing the impeller. The impeller includes a first molded piece coupled to a second molded piece. The first molded piece includes impeller vanes, a motor hub, a nose, and an eye. The second molded piece includes a cover and a hole through the cover. The cover is coupled to the impeller vanes around the motor hub so that the motor hub extends through the hole.