Outboard Motor Damper Isolation via Crankcase Segmentation
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Solution Overview
Problem
Existing outboard motors fail to effectively prevent external foreign matter, such as oil and water, from reaching the torsional damper connected to the crankshaft, leading to changes in the damper's characteristics and potential damage.
Innovation Solution
The outboard motor design incorporates an isolated space defined by the crankcase and support, which isolates the damper from external foreign matter, using seals and communication holes to prevent oil and water from entering, and includes a cowling for ventilation while maintaining a sealed environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the damper is exposed to external spaces where oil and water are present, then the structure is simpler and easier to access, but foreign matter reaches the damper causing changes in its characteristics
Solution Approach 1:
The patent divides the internal space into two distinct segments: an isolated space housing the damper and an external space containing oil and water. The crankcase wall acts as the segmentation barrier, creating separate zones with different environmental conditions to protect the damper from foreign matter while maintaining structural simplicity.
Solution Approach 2:
The patent extracts the damper from the general engine environment and places it in a dedicated isolated space. This extraction removes the damper from direct exposure to oil and water present in the external space, thereby protecting it from foreign matter contamination while keeping the overall structure compact.
2Object-affected harmful factors
If the isolated space is completely sealed, then foreign matter is prevented from entering, but ventilation is insufficient causing temperature increase
Solution Approach 1:
The patent applies local quality by creating different sealing conditions in different areas of the isolated space. The crankcase wall provides complete sealing in most areas to exclude foreign matter, while specific localized openings are provided for ventilation. This allows the space to simultaneously achieve both foreign matter exclusion and temperature control through strategically placed openings.
3Volume of moving object
If vertical space is reduced to minimize motor size, then compactness is improved, but isolation effectiveness may be compromised
Solution Approach 1:
The patent transitions from vertical isolation to horizontal/directional isolation by orienting the isolated space such that the damper is positioned in a region naturally protected by the crankcase structure. The isolation is achieved through the spatial arrangement and orientation of components rather than solely through vertical separation, allowing compact vertical dimensions while maintaining effective isolation from foreign matter.
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
This solution effectively prevents foreign matter from reaching the damper, reducing changes in its characteristics and minimizing damage, while also reducing the vertical size of the outboard motor and maintaining efficient ventilation.
Implementation Method 1
a rubber member which is made of a vulcanized rubber composition and is disposed between the mount and the mass member in the torsional damper
Implementation Method 2
a vulcanized rubber composition comprising a base rubber and a crosslinking agent
Implementation Method 3
a crosslinking agent which is at least one selected from the group consisting of a polyfunctional cyanate ester and an isocyanate compound
Data Source
AI summary
An outboard motor includes an engine, a crankshaft, a crankcase, a support that contacts a lower end of the crankcase, and a damper connected to a lower portion of the crankshaft and disposed in an isolated space defined by the crankcase and the support.