Sheet Metal Impeller Hub via Bent Web Fasteners
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Solution Overview
Problem
Existing impellers for pumps and fans made of sheet metal are costly to produce due to the need for a cylindrical hub, which increases weight and mass moment of inertia, and are complex to assemble, especially for smaller devices.
Innovation Solution
The remaining material areas between the blades are bent towards the rear to form fastening parts that create a hub for the pump or fan shaft, allowing for a simple and inexpensive manufacturing process while reducing weight and mass moment of inertia, with the fastening parts being bent to at least 90 degrees to securely hold the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cylindrical hub is formed by deforming the central area of the impeller plate, then the pump shaft can be fastened securely, but the production cost increases and the weight increases
Solution Approach 1:
The impeller is divided into functional zones: the central area forms a flat hub for shaft mounting, while the remaining material between blades forms web-shaped fastening parts. This segmentation allows each part to serve its specific function without unnecessary material, reducing overall weight and manufacturing complexity while maintaining secure shaft fastening.
Solution Approach 2:
Different regions of the impeller are given different properties: the central area is kept flat for simple shaft mounting, while the material between blades is bent into web-shaped fastening parts. This local differentiation optimizes both manufacturing ease and functional performance without requiring a heavy cylindrical hub throughout the entire impeller.
2Reliability
If a cylindrical hub is formed by deforming the central area of the impeller plate, then the pump shaft can be fastened securely, but the weight and mass moment of inertia increase
Solution Approach 1:
The impeller uses segmented fastening parts (webs) distributed between the blades rather than a solid cylindrical hub. This segmentation maintains the necessary structural support for secure shaft fastening while removing excess material, significantly reducing the impeller's weight and mass moment of inertia.
Solution Approach 2:
The hub region employs a web-like structure with intentional voids between the blades rather than a solid cylindrical form. This porous/webbed configuration provides sufficient structural integrity for shaft mounting while minimizing material usage, thereby reducing weight and rotational inertia.
3Ease of manufacture
If the remaining material areas between the blades are bent towards the rear to form fastening parts, then the manufacturing process becomes simple and inexpensive, but the structural complexity increases
Solution Approach 1:
The hub formation and blade fastening functions are merged into a single integrated structure. The web-shaped fastening parts are formed directly from the material between the blades during the same bending process that creates the hub, eliminating separate manufacturing steps while achieving both structural integrity and functional requirements.
Solution Approach 2:
The material between the blades serves dual purposes: it forms the web-shaped fastening parts and simultaneously creates the hub structure. The bending process transforms the flat material into a three-dimensional structure that self-organizes into both functional elements, simplifying manufacturing while creating a complex but efficient geometry.
4Reliability
If the fastening parts are bent backwards by at least 90 degrees, then a secure hold with positive fit on the shaft is achieved, but the manufacturing complexity increases
Solution Approach 1:
Instead of bending the fastening parts forward or laterally to engage the shaft, the design inverts the approach by bending them backward toward the rear of the impeller. This backward bending creates an interference fit that locks the shaft in place, achieving secure retention through a counterintuitive geometric configuration.
Solution Approach 2:
The fastening parts are bent into curved surfaces that match the cylindrical geometry of the pump shaft. This curvature allows the web-shaped fastening parts to conform to the shaft surface, creating a positive fit through surface matching rather than through complex mechanical interlocking features.
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to an impeller (1) of a pump or a fan, made of a single piece of material, particularly sheet metal, having a flat central region (2). The vanes (3) are formed on the outer edge of said region and are bent, wherein remaining material regions between the vanes (3) are bent partially towards the back and form fastening elements for the pump shaft (8).