Outboard Motor Protruding Member Segmentation for Weight Reduction
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Solution Overview
Problem
Conventional outboard motor engines face issues with increased size and weight due to the need for larger bolt sizes and components, which complicates the structure and reduces drivability, especially in watercraft applications.
Innovation Solution
A protruding member for an outboard motor engine is designed with an elongate shaft having a base side and a protruding end side, where the drive pulley is axially aligned with the crankshaft, and the flywheel is secured using a tightening member with holes oriented eccentrically to the drive pulley, allowing for independent sizing and reducing the overall engine size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the outer diameter of the protruding member is increased to accommodate larger bolts, then the strength of the bolts is improved, but the size and weight of the engine increase
Solution Approach 1:
The protruding member is divided into two functionally independent sections: a base side for mounting the drive pulley and a protruding end side for securing the flywheel. This segmentation allows each section to be optimized independently - the base side can be sized for pulley mounting while the protruding end side is sized for flywheel attachment, eliminating the need to increase the entire member size to accommodate larger bolts.
Solution Approach 2:
The bolt holes are positioned at different axial locations on the protruding end side rather than requiring a uniformly larger diameter. By utilizing the axial dimension and positioning holes at specific locations, the design achieves adequate bolt strength without increasing the overall outer diameter of the protruding member.
2Ease of manufacture
If the size of the protruding member is increased to match larger drive pulley inner diameter, then the drive pulley can be properly fitted, but the engine size and weight increase
Solution Approach 1:
The protruding member is segmented into a base side and protruding end side, allowing the base side to be specifically sized for drive pulley mounting while the protruding end side serves flywheel attachment. This eliminates the need to enlarge the entire protruding member to accommodate pulley fitting requirements.
3Ease of manufacture
If the drive pulley inner diameter is enlarged to match larger protruding member outer diameter, then proper matching is achieved, but the outer diameter of the driven pulley must also be enlarged, increasing engine size
Solution Approach 1:
By segmenting the protruding member into base side and protruding end side with independent sizing capabilities, the drive pulley inner diameter can be optimized for engagement without being constrained by the need to match a uniformly larger protruding member diameter. This allows the driven pulley to maintain its original size, preventing engine enlargement.
4Adaptability or versatility
If the drive pulley is formed separately from the protruding member, then the structure is more flexible, but the number of parts increases and complexity is reduced
Solution Approach 1:
The drive pulley is integrated with the protruding member by forming it as a single piece, eliminating the need for separate components and reducing the number of parts. This merging simplifies the overall structure while maintaining the flexibility to optimize the base side for pulley mounting.
Data Source
AI summary
An outboard motor engine and a protruding member for use therewith are provided. The outboard motor engine can have a crankshaft whose first end can be connected to a driven member. The protruding member can extend outwardly in the axial direction from a second end of the crankshaft and rotate about an axis with the crankshaft. A flywheel can be fixed on a protruding end side of the protruding member by a tightening member. A drive pulley can be fixed on a base side of the protruding member on the axis. The tightening member can be oriented eccentrically with respect to the drive pulley in the axial direction of the protruding member.