Outboard Motor Mounting Cradle Vibration Isolation
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Solution Overview
Problem
Existing outboard motor mounting systems fail to provide optimal vibration isolation and structural support while accommodating tight packaging requirements on marine vessels, particularly when multiple engines are mounted on a transom.
Innovation Solution
A mounting system comprising a support cradle with upper and lower structural support sections, paired with upper and lower mounts that utilize tubular extrusions and elastomeric materials to distribute loads and isolate vibrations, ensuring balanced thrust transmission and reduced engine movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-plane connector support system is used, then the device complexity is reduced, but vibration isolation performance deteriorates due to inadequate load distribution
Solution Approach 1:
The support system is segmented into two distinct planes: an upper plane with first connectors and a lower plane with second connectors. This segmentation allows independent optimization of each plane's function, with the upper plane handling primary support and the lower plane providing additional vibration isolation, thereby improving overall reliability without excessive complexity
Solution Approach 2:
The mounting system transitions from a single-plane configuration to a two-plane configuration, adding a vertical dimension to the connector arrangement. This dimensional change enables better spatial distribution of connectors around the driveshaft, improving vibration isolation through enhanced load distribution across multiple elevation levels
2Reliability
If multiple connectors are added to improve vibration isolation, then vibration isolation performance is improved, but device complexity increases
Solution Approach 1:
Both the upper and lower connectors serve dual functions: providing structural support and isolating vibrations. The connectors are designed with elastomeric elements that simultaneously handle load-bearing and vibration damping, reducing the need for separate specialized components and thereby limiting complexity increase
Solution Approach 2:
The connectors incorporate composite structures combining rigid mounting elements with elastomeric vibration-isolating materials. This composite approach allows a single connector component to provide both structural support and vibration isolation, improving reliability without proportionally increasing device complexity
3Reliability
If connectors are positioned far from the driveshaft axis, then vibration isolation is improved, but structural support strength deteriorates
Solution Approach 1:
The system uses a two-plane configuration where connectors are positioned at different radial distances and vertical elevations. Upper connectors may be positioned closer to the axis for strength, while lower connectors extend farther for vibration isolation, with the vertical separation allowing both positioning strategies to coexist without compromising either strength or isolation performance
4Adaptability or versatility
If a pedestal mount with stationary vertical steering axis is used, then adaptability to conventional outboard motors is improved, but packaging efficiency deteriorates due to increased lateral displacements
Solution Approach 1:
The system employs dynamic connectors with elastomeric elements that allow controlled movement and compliance in multiple directions. This dynamic design accommodates the steering and tilting motions of conventional outboard motors while reducing lateral displacements through the compliant nature of the elastomeric materials, thereby improving packaging efficiency without sacrificing adaptability
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 system achieves effective vibration isolation and maintains low lateral displacements, accommodating multi-engine configurations by strategically positioning mounts to decouple modal frequencies and enhance roll stiffness, thus improving overall performance and packaging efficiency.
Implementation Method 1
Each connector comprises an elastomeric portion for the purpose of isolating the vibration
Implementation Method 2
Each connector comprises an elastomeric portion
Implementation Method 3
paired with upper and lower mounts that utilize tubular extrusions and elastomeric materials to distribute loads and isolate vibrations, ensuring balanced thrust transmission and reduced engine movement
Data Source
AI summary
A system for mounting an outboard motor propulsion unit to a marine vessel transom is disclosed. The propulsion unit's midsection has an upper end supporting an engine system and a lower end carrying a gear housing. The mounting system includes a support cradle having a head section coupled to a transom bracket, an upper structural support section extending aftward from the head section and along opposite port and starboard sides of the midsection, and a lower structural support section suspended from the upper structural support section and situated on the port and starboard sides of the midsection. A pair of upper mounts couples the upper structural support section to the midsection proximate the engine system. A pair of lower mounts couples the lower structural support section to the midsection proximate the gear housing. At least one of the upper and lower structural support sections comprises an extrusion or a casting.