One-Piece Fan Hub Casting for Flexible Blade Mounting
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Solution Overview
Problem
Existing fan designs are complex, requiring numerous components and assembly challenges, especially for large or heavy-duty fans, which need to balance stiffness, strength, and cost while accommodating various coupling arrangements and blade angles.
Innovation Solution
A unitary hub assembly with a cast or machined substantially circular hub plate and radially extending elongated root sections, allowing for customizable fan designs by machining root mounting surfaces and coupling fan blades at desired angles, along with a method that includes pressing a bushing into an axial bore for secure mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional multi-component hub design is used, then various coupling arrangements and blade angles can be accommodated, but the number of components and assembly complexity increases
Solution Approach 1:
The patent merges multiple separate components (hub plate, root sections, mounting surfaces) into a single unitary hub assembly that is cast as one piece. This integration maintains the ability to accommodate various coupling arrangements and blade angles through design flexibility while eliminating the need for multiple separate parts and their associated assembly operations.
Solution Approach 2:
The unitary hub assembly is designed to perform multiple functions: it serves as the central structural element, provides mounting surfaces for fan blades at various angles, accommodates different coupling arrangements, and maintains structural integrity. This multi-functionality replaces what would traditionally require multiple specialized components.
2Device complexity
If a unitary hub assembly is used, then component inventory and assembly complexity are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The hub assembly is cast in its complete unitary form with all root sections and mounting surfaces prepared in advance. This preliminary formation of the entire structure allows for subsequent machining operations to be performed on pre-positioned features, reducing the cumulative precision errors that would arise from assembling multiple machined components.
Solution Approach 2:
The invention changes the manufacturing approach from machining multiple separate components to casting a unitary structure with controlled dimensional parameters. The casting process allows for better control of overall geometry and fit, while machining is then applied only to specific mounting surfaces, reducing the total precision requirements compared to machining all interfaces on separate parts.
3Strength
If large fan designs are used, then sufficient stiffness and strength are achieved, but weight and cost increase
Solution Approach 1:
The unitary hub assembly employs local quality optimization where material is distributed non-uniformly throughout the structure. The casting process allows for varying wall thicknesses and material density in different regions, providing enhanced stiffness and strength where needed while reducing material usage and weight in less critical areas.
Solution Approach 2:
The hub assembly utilizes composite material construction combining a cast metal base structure with machined surface treatments and potentially different material properties in different regions. This composite approach optimizes the strength-to-weight ratio by using materials and structures specifically tailored for each functional requirement within the hub.
Data Source
AI summary
A hub assembly for construction of a fan includes a hub plate having a front face, a rear face, and an annular surface extending between the front face and the rear face. The hub plate defines a hub assembly axis extending through the front face and the rear face which is configured to coincide with the fan axis. The hub assembly further includes a plurality of elongated root sections that are circumferentially spaced apart and extend radially from the annular surface. The elongated root sections have a substantially circular cross-section. The hub plate and the plurality of elongated spokes are unitarily formed.