Two-Piece Hub Propeller Assembly Drag Reduction
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Solution Overview
Problem
Traditional propeller hub fabrication methods using die casting often result in performance degradation due to incorporated tapers, leading to increased drag and reduced hydrodynamic efficiency, and are costly and time-consuming to modify.
Innovation Solution
A two-piece hub propeller assembly is fabricated using individually cast parts that can be joined, allowing for dissimilar materials and reducing weight and cost, with a conical shape that minimizes drag and incorporates spokes to absorb vibrations, and various joining methods such as bonding, bolting, or fastening to secure the hub portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional die casting methods are used to fabricate propeller hub, then manufacturing cost and time are reduced, but hydrodynamic efficiency deteriorates due to incorporated tapers causing increased drag
Solution Approach 1:
The propeller hub is divided into two separate pieces: a hub body and a hub cap. This segmentation allows each component to be manufactured independently using optimal methods (die casting for both), avoiding the need to incorporate tapers in a single-piece construction. The separate pieces are then joined together to form the complete hub assembly, eliminating the hydrodynamic drag caused by tapered features while maintaining manufacturing efficiency.
2Strength
If single-piece hub design is used, then structural integrity is improved, but weight and cost increase due to material usage
Solution Approach 1:
The hub is segmented into a hub body and hub cap that can be manufactured from dissimilar materials optimized for their specific functions. The hub body can be made from a material optimized for structural strength, while the hub cap can be made from a lighter material. This segmentation allows weight reduction while maintaining overall structural integrity through proper material selection and joining methods.
Solution Approach 2:
The two-piece hub assembly enables the use of composite construction with dissimilar materials. The hub body and hub cap can be made from different materials selected for their specific properties, creating a composite structure that optimizes both strength and weight. This approach allows the use of lighter materials in non-critical areas while maintaining strength where required.
3Weight of moving object
If dissimilar materials are used in hub construction, then weight and cost are reduced, but manufacturing complexity increases
Solution Approach 1:
The hub is segmented into two separately manufacturable components (hub body and hub cap) that can be produced using standard die casting processes for each material type. This segmentation simplifies the manufacturing process compared to attempting to create a single-piece hub from dissimilar materials, as each piece can be optimized for its specific material and function, then joined using conventional techniques.
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
The two-piece assembly reduces drag, decreases fuel or power consumption, increases marine vessel range, and allows for weight and cost reductions by using dissimilar materials while maintaining efficient torque transfer and vibration absorption.
Implementation Method 1
an elastic hub component on an opposite end. The elastic hub component has planar outer engagement surfaces that abut corresponding inner engagement surfaces on the propeller hub's inner bore. Upon initial propeller shaft rotation, the elastic hub component deflects and allows the adapter component to rotationally travel relative to the propeller hub
Implementation Method 2
The elastic hub component has a spring rate small enough to reduce clutch rattle yet large enough to isolate transmission shift clunk
Data Source
AI summary
A propeller hub assembly for a marine drive having a propeller shaft is provided. The propeller hub assembly includes a first hub portion having a first main body and multiple propeller blades extending radially therefrom. The first main body is substantially cone-shaped and tapers inwardly from a first keyed end proximate the multiple propeller blades. The propeller hub assembly further includes a second hub portion having a second keyed end. The first hub portion is coupled to the second hub portion such that the first keyed end is mated to the second keyed end, and the first hub portion and the second hub portion are configured to engage the propeller shaft such that rotation of the propeller shaft causes rotation of the first hub portion and the second hub portion.