Propeller Damper Staged Elastic Deformation for Noise Reduction
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Solution Overview
Problem
Vessel propulsion systems experience rattling noise and shift shock due to the interaction between the propeller damper and the bevel gear mechanism, which affects the comfort and merchantability of the vessel.
Innovation Solution
A propeller design featuring a bushing with a first cylinder portion and a propeller body with second, third, and fourth projections, along with a propeller damper comprising individually separable first and second dampers that elastically deform in stages to manage torque transmission and reduce noise and shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a propeller damper is used to reduce torque transmission, then rattling noise and shift shock are reduced, but the propeller cannot effectively transmit driving force at low speeds
Solution Approach 1:
The propeller is divided into two independent dampers: a first damper (propeller damper) that reduces rattling noise during normal operation, and a second damper (low-speed damper) that activates when the propeller blade angle is reduced below a predetermined value to transmit driving force effectively at low speeds. This segmentation allows each damper to specialize in different operational conditions.
Solution Approach 2:
The system dynamically switches between different damper configurations based on propeller blade angle. When the blade angle is large (normal speed), the first damper operates to reduce noise. When the blade angle is reduced (low speed), the second damper engages to improve force transmission, creating a dynamic adaptation to operating conditions.
2Object-affected harmful factors
If the propeller damper is made softer to reduce rattling noise, then noise decreases, but the damper cannot withstand high torque during shift-in
Solution Approach 1:
The torque transmission function is segmented between two dampers with different characteristics. The first damper uses softer elastic material to reduce rattling noise during normal operation, while the second damper provides additional torque transmission capacity during shift-in when high torque is required, eliminating the need to compromise noise reduction for strength.
Solution Approach 2:
The system effectively creates a composite damping structure by combining two dampers with different elastic material properties. The first damper contributes noise reduction through its softer material, while the second damper contributes torque transmission strength, achieving both functions simultaneously that neither damper could achieve alone.
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 staged elastic deformation of the propeller damper effectively reduces rattling noise and shift shock, enhancing the operational comfort and marketability of the vessel propulsion system.
Implementation Method 1
a propeller damper comprising a first damper and a second damper that are located side by side along an axial direction between the first cylinder portion and the second cylinder portion and that are separated from each other by a separation portion so as to be individually elastically deformable
Data Source
AI summary
A propeller includes a bushing, a propeller body, and a propeller damper. The bushing includes a first cylinder portion surrounding the propeller shaft and a first projection protruding outwardly in a radial direction of the propeller from an outer peripheral surface of the first cylinder portion. The propeller body includes a second cylinder portion surrounding the bushing and a second projection protruding inwardly in the radial direction from an inner peripheral surface of the second cylinder portion. The first and second projections are arranged along a rotation direction of the propeller. The propeller damper includes first and second dampers side by side along an axial direction of the propeller between the first and second cylinders. The first and second dampers are separated from each other by a separation portion, and are individually elastically deformable.