Marine Transmission Noise Reduction Case With Deformable Cladding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric and hybrid boats experience significant noise from marine transmissions, particularly at low speeds, which affects passenger comfort and may require hearing protection.
Innovation Solution
A noise reduction case comprising a structural frame and noise reduction cladding, including a displacement section that deforms to accommodate relative movements, coupled to the propulsion unit to reduce noise and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rigid noise reduction case is fixed to the engine bed, then noise isolation is improved, but the case cannot accommodate transmission displacement during operation
Solution Approach 1:
The mounting structure transitions from a rigid fixed connection to a dynamic system that accommodates transmission displacement. The structural frame is detachably mounted to the engine bed, allowing the noise reduction case to be positioned around the transmission while following its movement during operation, thus maintaining noise isolation without restricting transmission mobility.
Solution Approach 2:
The noise reduction system is divided into separable components: a structural frame that can be detachably mounted to the engine bed, and a noise reduction cladding that surrounds the transmission. This segmentation allows the case to be positioned optimally around the transmission while accommodating its displacement through the detachable mounting mechanism.
2Object-affected harmful factors
If the transmission is completely enclosed in a rigid case, then noise reduction is improved, but access for maintenance and inspection becomes difficult
Solution Approach 1:
The noise reduction case is designed with detachable mounting to the engine bed, creating separable sections that allow easy access to the transmission for maintenance and inspection while maintaining complete enclosure during operation. The structural frame can be detached to provide access pathways.
Solution Approach 2:
The noise reduction case is designed with predetermined access points and detachable mounting features that facilitate easy removal and reinstallation. This preliminary design consideration ensures that maintenance access is built into the structure without compromising the noise reduction enclosure.
3Strength
If thick materials are used for the structural frame, then structural strength is improved, but weight of the noise reduction case increases
Solution Approach 1:
The structural frame utilizes composite construction combining aluminum extrusions with reinforcing ribs and strategic material distribution. This composite approach provides high structural strength to support the noise reduction cladding and withstand vibrations, while keeping weight lower than solid thick material construction would require.
Solution Approach 2:
The structural frame employs varying wall thicknesses and strategic rib placement, providing thicker material only where structural strength is critically needed (at mounting points and support locations) while using thinner material in less critical areas, thus optimizing the strength-to-weight ratio of the overall structure.
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
Effectively reduces transmission noise and vibrations, enhancing passenger comfort and eliminating the need for hearing protection, especially at low speeds.
Implementation Method 1
The displacement section is configured to deform in response to a relative movement between the transmission and the engine bed of the propulsion unit
Implementation Method 2
The displacement section is configured to deform in response to a relative movement between the transmission and the engine bed of the propulsion unit, thereby reducing a noise of the transmission
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present disclosure relates to a noise reduction case (10) for a transmission (102) of a propulsion unit (100) of a watercraft (200), the propulsion unit (100) comprising a motor (112) for driving a propeller (106) via the transmission (102). The propulsion unit further comprises an engine bed (104) for supporting the motor (112). The noise reduction case comprises a structural frame (12) mechanically couplable to the propulsion unit (100). The noise reduction case (10) further comprises a noise reduction cladding (20) arranged on the structural frame (12) for reducing a noise of the transmission (102). The noise reduction cladding (20) comprises a displacement section (30; 34) configured to deform in response to a relative movement between the transmission (102) and the engine bed (104) of the propulsion unit (100). The invention further relates to a method for mounting such a noise reduction case (10), a propulsion unit (100) with such a noise reduction case (10), and a watercraft (200) with such a propulsion unit (100).