Non-Circular Inner Wedge Mounts for Outboard Motor Vibration Attenuation
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Solution Overview
Problem
Existing mount designs for outboard motors on marine vessels face challenges in minimizing size and weight while maintaining effectiveness and durability, particularly in attenuating fore-aft shaking forces within limited design space constraints.
Innovation Solution
The use of non-circular inner wedges with specific angular configurations in combination with elastomeric spacers in mounts that radially and axially extend, allowing for a desired ratio of shear to compression force, enabling compact designs that effectively attenuate fore-aft shaking forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional mount designs are used, then the mounting arrangement can support outboard motors, but the size and weight cannot be minimized
Solution Approach 1:
The inner wedge is designed with a non-circular cross-section featuring asymmetric surfaces at different angles (first angle and second angle) relative to the horizontal and vertical directions. This asymmetric geometry enables the mount to achieve desired shear-to-compression force ratios while minimizing material usage and overall size, directly addressing the contradiction between weight reduction and vibration attenuation effectiveness
Solution Approach 2:
The invention varies the angles of the inner wedge surfaces and the geometry of the elastomeric spacer to optimize the shear-to-compression force ratio. By changing these geometric parameters, the mount achieves effective fore-aft shaking force attenuation with a compact design, resolving the contradiction between maintaining reliability and minimizing weight
2Weight of moving object
If mount size is reduced, then weight decreases, but the ability to attenuate fore-aft shaking forces is compromised
Solution Approach 1:
The non-circular inner wedge with asymmetric surface angles creates optimized force distribution pathways that maximize vibration attenuation per unit of material. This asymmetric design allows the compact mount to effectively attenuate fore-aft shaking forces despite reduced size
Solution Approach 2:
The elastomeric spacer is positioned and dimensioned to provide localized damping properties where they are most needed for fore-aft shaking force attenuation. The local quality of the elastomeric material at specific positions optimizes force attenuation while minimizing overall mount size and weight
3Ease of manufacture
If the mount design is simplified, then manufacturing becomes easier, but the range of radial and axial stiffness rates is limited
Solution Approach 1:
The invention achieves a wide range of stiffness rates by varying geometric parameters (angles, dimensions) of the inner wedge and elastomeric spacer rather than changing materials or complex structures. This approach maintains manufacturing simplicity while providing design flexibility for different stiffness requirements
Solution Approach 2:
The basic mount structure with adjustable geometric parameters serves multiple functions: supporting the outboard motor, attenuating vibrations, and providing customizable stiffness characteristics. This multi-functionality is achieved through a relatively simple design that can be adapted to various requirements by modifying angles and dimensions
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 configuration allows for a compact, adaptable mounting arrangement that achieves a wide range of radial and axial stiffness rates, maintaining performance in terms of fore-aft spring rate and elastic center location, while minimizing size and weight.
Implementation Method 1
an elastomeric spacer between the outer shell and the inner wedge
Implementation Method 2
attenuating fore-aft shaking forces
Data Source
AI summary
A mounting arrangement is for supporting an outboard motor with respect to a marine vessel extending in a fore-aft plane. The mounting arrangement comprises first and second mounts that each have an outer shell, an inner wedge concentrically disposed in the outer shell, and an elastomeric spacer between the outer shell and the inner wedge. Each of the first and second mounts extend along a axial direction, along a vertical direction that is perpendicular to the axial direction, and along a horizontal direction that is perpendicular to the axial direction and perpendicular to the vertical direction. The inner wedges of the first and second mounts both have a non-circular shape when viewed in a cross-section taken perpendicular to the axial direction. The non-circular shape comprises a first outer surface that extends transversely at an angle to the horizontal and vertical directions. The non-circular shape comprises a second outer surface that extends transversely at a different, second angle to the horizontal and vertical directions. A method is for making the mounting arrangement.