Demountable Propeller Hub Segmentation for Blade Replacement
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Solution Overview
Problem
Conventional marine propellers with integrally cast blades and hubs are costly to produce and replace, suffer from non-uniform blade mass and material discontinuities, leading to reduced thrust performance and balance issues due to rigid connections weakening over time.
Innovation Solution
A demountable propeller design featuring a cylindrical hub split into two parts with step-like housings and protrusions, allowing for secure connection via bolts and nuts, enabling easier production and assembly while maintaining rigidity and balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If propellers are cast in one piece with integrally produced blades and hub, then structural strength and rigidity are improved, but manufacturing cost increases and blade damage requires entire propeller replacement
Solution Approach 1:
The propeller is divided into separable components: the hub and blades can be detached from each other. The hub is further segmented into two parts (first hub part and second hub part) that can be assembled together. This segmentation allows individual blade replacement when damaged, reducing manufacturing costs while maintaining structural integrity through proper connection mechanisms.
2Stability of the object's composition
If blades are integrally produced with the hub, then structural rigidity is improved, but blade-hub connection rigidity decreases over time due to vibrations
Solution Approach 1:
The connection structure between hub parts includes pre-designed reinforcing ribs and positioning protrusions that are formed during manufacturing. These features are built in advance to prevent connection loosening due to vibrations, maintaining reliable blade-hub connection rigidity over time without requiring integral production.
3Power
If blades are provided all through the hub thickness, then thrust performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The hub is segmented into two parts with blades extending through the combined thickness. This segmentation allows for simplified manufacturing of each hub part while achieving the desired thrust performance through the complete blade-hub integration when assembled. The modular approach reduces overall device complexity.
4Ease of repair
If demountable blade design is used, then ease of repair is improved, but blade uniformity and propeller balance deteriorate due to casting variations
Solution Approach 1:
The connection interface between blades and hub includes positioning protrusions and housings with specific geometric parameters that ensure precise alignment and uniform positioning of each blade. This controlled parameter design compensates for casting variations, maintaining propeller balance while allowing easy blade removal and replacement.
Data Source
AI summary
A marine vessel propeller comprising an even number of blades such as 4, 6, 8, which can be mounted or demounted to a hub made of two parts each having the half of the blades. The blades can be rigidly connected to each other by means of connecting members.