Stern Drive Vibration Isolation via Resilient Isolators
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Solution Overview
Problem
Existing stern drive mounting systems for marine vessels fail to effectively isolate vibration forces, leading to potential damage and reduced performance due to inadequate vibration management.
Innovation Solution
The stern drive system incorporates resilient gimbal ring and driveshaft housing vibration isolators, comprising rubber cylinders and metal sleeves, which isolate vibration forces along vertical and horizontal axes, maintaining a center of gravity between these isolators to distribute and manage vibrations without altering the connection between the gimbal housing and the transom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rigid mounting systems are used to securely attach the stern drive to the vessel, then structural strength and stability are improved, but vibration forces are transmitted to the mounting structure causing potential damage and reduced performance
Solution Approach 1:
The patent introduces resilient vibration isolators as intermediary elements between the stern drive and mounting structure. These isolators comprise resilient members (such as rubber or elastomeric materials) positioned between the gimbal ring and driveshaft housing, and between the stern drive assembly and the vessel transom. The resilient members act as mediators that decouple the rigid connection, allowing vibration forces to be absorbed and isolated rather than transmitted to the mounting structure, thereby resolving the contradiction between structural strength and vibration transmission.
Solution Approach 2:
The patent changes the mechanical parameters of the mounting system by introducing elements with specific resilient properties. The vibration isolators are designed with controlled durometer values, hardness, and elasticity to optimize their vibration isolation characteristics. By adjusting parameters such as the resilience of the isolator materials, the number and arrangement of isolators, and their positioning relative to the center of gravity, the system achieves both structural support and vibration isolation, resolving the contradiction between strength and harmful vibration forces.
2Object-affected harmful factors
If vibration isolators are added to isolate vibration forces, then protection from vibration damage is improved, but device complexity increases
Solution Approach 1:
The patent merges the vibration isolation function with existing structural components of the stern drive. The resilient vibration isolators are integrated into the mounting assembly rather than being separate add-on components. The isolators are positioned at strategic locations within the existing gimbal and driveshaft structure, combining structural support and vibration isolation functions in a unified design. This integration approach achieves effective vibration isolation while minimizing the increase in overall device complexity.
Solution Approach 2:
The vibration isolators serve multiple functions simultaneously: they provide structural support to hold the stern drive assembly, isolate vibration forces from the mounting structure, accommodate thermal expansion and contraction, and allow for minor misalignments during installation. This multi-functionality reduces the need for additional separate components, thereby achieving effective vibration isolation without proportionally increasing device complexity.
3Object-affected harmful factors
If the center of gravity is positioned between the vibration isolators, then vibration distribution and isolation effectiveness are improved, but manufacturing and assembly precision requirements increase
Solution Approach 1:
The patent applies local quality by positioning vibration isolators at specific locations relative to the center of gravity of the stern drive assembly. The isolators are strategically placed at the gimbal ring, driveshaft housing, and mounting flange areas, which are identified as key vibration generation and transmission points. This localized positioning approach optimizes vibration isolation effectiveness at critical areas without requiring precise center of gravity positioning throughout the entire assembly, thereby reducing overall manufacturing precision requirements while maintaining effective vibration distribution and isolation.
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 effectively isolates vibration forces, enhancing the stability and performance of the stern drive system without requiring changes to the mounting connection, thereby protecting the vessel and improving operational efficiency.
Implementation Method 1
a resilient driveshaft housing vibration isolator (41) is located along the second pivot axis (38). The resilient vibration isolator isolates vibration forces on the driveshaft housing (22). A resilient gimbal ring vibration isolator (72) is located along the trim axis (24)
Implementation Method 2
The gimbal ring vibration isolator and the a trim actuator resilient vibration isolator operate together to isolate vibration forces on the stern drive (10)
Data Source
AI summary
A stern drive is for a marine vessel. The stern drive comprises a gimbal housing that is configured for connection to the marine vessel, a gimbal ring that is steerable with respect to the gimbal housing about a vertical steering axis, a driveshaft housing that is connected to the gimbal ring, and a trim actuator that is configured to trim the driveshaft housing about a horizontal trim axis. The trim actuator has a first end that is pivotably connected to the gimbal ring at a horizontal first pivot axis and a second end that is pivotably connected to the driveshaft housing at a horizontal second pivot axis. A resilient driveshaft housing vibration isolator is located along the second pivot axis. The resilient vibration isolator isolates vibration forces on the driveshaft housing. A resilient gimbal ring vibration isolator is located along the trim axis. The gimbal ring vibration isolator isolates vibration forces on the gimbal ring.