Propeller Shock Absorber Damper for Vessel Gear Shift Noise
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Solution Overview
Problem
Existing propeller units for vessel propulsion apparatuses experience unsatisfactory shock absorption and noise reduction, particularly during gear shifts and when the dog clutch engages the forward or backward gear, due to rotational pulsations from the drive shaft, leading to uncomfortable vibrations and sounds.
Innovation Solution
A shock absorber with a damper made of elastic material is placed between the outer peripheral surface of the bushing and the inner peripheral surface of the inner hub, featuring a deformation-absorbing space that deforms as the bushing and inner hub rotate, effectively reducing shocks and noises by allowing the damper to compress and absorb energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional damper made of elastic material is disposed between the bushing and the inner hub, then some shock absorption is achieved, but the shock absorption and noise reduction remain unsatisfactory during gear shifts and dog clutch engagement
Solution Approach 1:
The damper is divided into multiple segments or layers with different elastic coefficients. The damper includes a first damper portion and a second damper portion, each with different shock absorption characteristics, allowing optimized performance across different operating conditions including gear shifts and dog clutch engagement.
Solution Approach 2:
Different portions of the damper are assigned different elastic coefficients to address local shock absorption needs. The first damper portion has a higher elastic coefficient for handling high-intensity shocks during gear shifts, while the second damper portion has a lower elastic coefficient for continuous vibration damping during normal operation.
2Device complexity
If the damper is made of a single elastic material with uniform properties, then the structure is simple, but it cannot effectively handle both high-intensity shocks during gear shifts and continuous vibrations during normal operation
Solution Approach 1:
The damper is segmented into multiple functional portions with different elastic coefficients. This segmentation allows the damper to handle both high-intensity shocks during gear shifts and continuous vibrations during normal operation, achieving comprehensive shock absorption performance.
Solution Approach 2:
The damper uses composite elastic materials or materials with different elastic coefficients in different portions. This composite structure enables the damper to provide both high-intensity shock absorption during gear shifts and effective vibration damping during continuous operation.
3Adaptability or versatility
If the dog clutch is designed to engage the forward or backward gear, then the propulsion direction can be switched, but impact sounds and vibrations are generated due to speed difference and inertial mass
Solution Approach 1:
The damper is positioned between the bushing and the inner hub to provide cushioning before the impact of dog clutch engagement is transmitted to the propeller shaft. This beforehand cushioning reduces impact sounds and vibrations during gear shifting and propulsion direction changes.
Solution Approach 2:
The damper acts as an intermediary element between the bushing and the inner hub, absorbing and dampening the impact forces generated during dog clutch engagement. This intermediary structure reduces the transmission of shock and vibration to the propeller shaft while maintaining the adaptability of propulsion direction switching.
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 solution significantly reduces shocks and noises during gear shifts and when the dog clutch engages, providing a more comfortable operating experience and improving the overall durability of the propeller unit by dispersing impulsive forces through the use of multiple ribs and a rotation restricting projection to prevent excessive load on the damper.
Implementation Method 1
a damper (D) made of an elastic material such as rubber... in a state in which the damper has been elastically deformed by relative rotation between the bushing and the inner hub
Implementation Method 2
The deformation-absorbing space is deformed such that the first portion and the second portion approach each other in a state in which the damper has been elastically deformed by relative rotation between the bushing and the inner hub
Data Source
AI summary
A damper is disposed between an outer peripheral surface of a bushing and an inner peripheral surface of an inner hub. The damper includes a first portion facing a rib of the bushing, a second portion facing a rib of the inner hub, and a connection portion by which the first portion and the second portion are connected to each other. In a state in which a rotational force has not been applied between the bushing and the inner hub, the damper includes a cross-sectional shape that defines a deformation-absorbing space positioned between the first portion and the second portion. The deformation-absorbing space is deformed such that the first portion approaches the second portion in a state in which the rib of the bushing and the rib of the inner hub have moved relatively by application of a rotational force between the bushing and the inner hub.