Propeller Damper Torque Transmission via Elastic Deformation
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Solution Overview
Problem
Conventional propeller dampers for vessel propulsion systems face limitations in maximum operating angle due to variations in dimensions of spline holes and shafts, which hinder performance improvement and torque transmission efficiency.
Innovation Solution
A propeller design featuring a bushing with integral protrusions and an elastically deformable damper, where the inner cylinder includes engagement protrusions and grooves for efficient torque transmission, reducing positional variations and enhancing assembly and maintenance by allowing easy insertion and removal of the damper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the maximum operating angle is increased to improve shock absorption performance, then the allowable relative rotation between propeller member and shaft is improved, but the positional variation due to spline hole and shaft dimension tolerances causes the actual maximum operating angle to deviate from the design value
Solution Approach 1:
The propeller damper is pre-assembled with the propeller member as an integrated unit before installation on the shaft. This preliminary assembly ensures that the damper's position is fixed relative to the propeller member, eliminating the issue of positional variation that would occur if the damper were separately installed on the shaft. The integrated unit is then mounted as a single assembly, ensuring consistent maximum operating angle regardless of shaft tolerance variations.
Solution Approach 2:
The propeller damper and propeller member are combined into a single integrated assembly. By merging these components, the patent eliminates the interface between separate parts that would be subject to dimensional tolerances. The damper becomes an inherent part of the propeller member assembly, ensuring that its position and orientation are fixed relative to the propeller blades, thereby maintaining consistent shock absorption performance.
2Manufacturing precision
If the propeller damper is securely fixed to the propeller shaft to maintain positional accuracy, then the maximum operating angle can be controlled, but the assembly and maintenance complexity increases
Solution Approach 1:
The propeller assembly is segmented into two main parts: the integrated propeller member with damper, and the separate shaft. By segmenting the assembly this way, the complex damping mechanism can be pre-assembled and tested as a unit, then installed as a single component. This reduces the overall assembly complexity compared to installing multiple separate components on the shaft, while still maintaining precise control over the maximum operating angle through the integrated design.
3Manufacturing precision
If the propeller damper is designed with high manufacturing precision to eliminate positional variation, then torque transmission efficiency is improved, but the cost and manufacturing difficulty increase
Solution Approach 1:
The propeller damper is pre-assembled with the propeller member in a controlled manufacturing environment where precise positioning can be achieved. This preliminary assembly allows for high precision to be attained during the initial manufacturing process rather than requiring high precision in the final installation. The integrated unit is then installed as a single component, eliminating the need for field adjustments and ensuring consistent torque transmission efficiency without requiring excessively tight tolerances on the shaft interface.
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 design increases the maximum operating angle, improves torque transmission efficiency, and simplifies assembly and maintenance by stabilizing the propeller damper characteristics and reducing eccentricity-induced deformation deviations.
Implementation Method 1
The propeller damper transmits a torque between the propeller member and the propeller shaft, and absorbs a shock between the propeller member and the propeller shaft... the propeller damper is made of an elastic material
Implementation Method 2
the inner cylinder includes engagement protrusions and grooves for efficient torque transmission
Data Source
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AI summary
A propeller (11) for a vessel propulsion apparatus (1) to be attached to a propeller shaft (10) extending in a front-rear direction of a vessel, the propeller (11) comprising: a bushing (31) configured to rotate together with the propeller shaft (10), the bushing (31) including a first cylindrical portion (40) surrounding the propeller shaft (10), and a first protrusion (41) protruding outward from the first cylindrical portion (40) that is integral with the first cylindrical portion (40); a propeller damper (32) made of an elastic material and disposed around the bushing (31); and an inner cylinder (25) including a second cylindrical portion (35) surrounding the bushing (31) via the propeller damper (32), and a second protrusion (36) protruding inward from the second cylindrical portion (35), the inner cylinder (25, 225) being configured to rotate with respect to the bushing (31) between a noncontact position, in which the first protrusion (41) and the second protrusion (36) are separated from each other in a circumferential direction (Dc), and a contact position, in which the first protrusion (41) and the second protrusion (36) come into contact with each other according to elastic deformation of the propeller damper (32).