Demountable Marine Propeller Hub Segmentation
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Solution Overview
Problem
Conventional marine propellers with integrally cast blades and hubs are costly to manufacture, require complex machining, and suffer from performance issues due to non-uniform blade production and rigidity problems, necessitating entire propeller replacement upon damage.
Innovation Solution
A propeller design featuring a cylindrical hub split into two parts with axially extending housings and protrusions, allowing for easy assembly and disassembly with connecting members, enabling production of propellers with a higher surface area ratio and improved rigidity through a step-like form that ensures proper alignment and secure connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If propellers are cast in one piece with integrally produced blades and hub, then structural strength is improved, but manufacturing cost increases and blade surface area ratio decreases
Solution Approach 1:
The propeller is divided into two separate parts: the hub and the blades. The hub is produced separately and the blades are attached to it, eliminating the need for complex one-piece casting. This segmentation allows for simpler, more cost-effective manufacturing processes while maintaining structural integrity through proper connection design.
Solution Approach 2:
The hub and blades are merged through a connection structure that combines the advantages of separate production with the structural benefits of integration. The connection design ensures uniform blade positioning and maintains overall propeller strength while enabling independent manufacturing of components.
2Strength
If propellers are cast in one piece with integrally produced blades and hub, then structural strength is improved, but machining complexity increases
Solution Approach 1:
By segmenting the propeller into hub and blade components, the machining operations are divided into simpler, more manageable tasks. Each component can be machined independently with standard equipment, avoiding the need for complex setup and large machining tracks required for one-piece propellers.
3Productivity
If blades are produced by casting, then production efficiency is improved, but blade uniformity decreases leading to balance problems
Solution Approach 1:
The hub is produced first with precisely positioned connection elements (such as recesses or mounting features) that serve as reference points. When blades are subsequently attached to the hub, these pre-positioned features ensure uniform spacing and orientation, eliminating balance problems while allowing efficient casting production of individual blades.
4Strength
If hub is made as single piece, then structural strength is improved, but adaptability for blade replacement decreases
Solution Approach 1:
The propeller is segmented into a permanent hub and replaceable blade components. The hub maintains its structural strength as a solid component, while the connection interface is designed to allow easy removal and replacement of blades. This enables maintenance and repair operations without replacing the entire propeller.
Solution Approach 2:
The design allows damaged blades to be discarded and replaced with new or refurbished blades while retaining the hub. This extends the service life of the propeller system and reduces waste, as only the damaged components need replacement rather than the entire assembly.
5Power
If blades are provided all through hub thickness, then thrust performance is improved, but manufacturing cost increases
Solution Approach 1:
The propeller structure is segmented into hub and blade components, allowing blades to extend through the hub thickness for optimal thrust performance. The separate production of hub and blades eliminates the need for expensive one-piece casting while maintaining the through-blade configuration that maximizes propulsion efficiency.
Data Source
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AI summary
Present invention relates to 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.