Steering Cylinder Fastening Rod Isolation Against Galvanic Seizure
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Solution Overview
Problem
The galvanic bridge effect between metal fastening rods and aluminum bull-horns in outboard marine motors leads to oxide accumulation, causing rotation blockage and wear, especially in humid and saline environments, compromising the tilt control mechanism and increasing component wear.
Innovation Solution
Introduce insulating elements made of plastic, such as bushings, between the ends of the fastening rod and the housing seats to prevent galvanic corrosion and wear, while retaining lubricating material to facilitate smooth rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal fastening rod and aluminum bull-horns are directly contacted, then strong mechanical connection is achieved, but galvanic corrosion occurs causing rotation blockage
Solution Approach 1:
The patent introduces an insulating element as an intermediary component between the metal fastening rod and aluminum bull-horns. This mediator prevents direct galvanic contact while maintaining the mechanical connection, thereby eliminating galvanic corrosion and preserving rotation capability without sacrificing connection strength.
Solution Approach 2:
The patent employs composite material construction by combining metal components (fastening rod, bull-horns) with non-metallic insulating elements. This composite approach allows the system to simultaneously achieve strong mechanical connection through metal components while preventing galvanic corrosion through the insulating material, thus resolving the contradiction between connection strength and rotation reliability.
2Ease of operation
If grease is applied to fastening rod ends, then lubrication is provided, but grease layer is removed during use requiring continuous replenishment
Solution Approach 1:
The insulating element is designed to self-retain lubricating material within its structure, eliminating the need for external grease application systems. The element serves itself by continuously providing lubrication through its inherent material properties or structured reservoir, ensuring long-lasting lubrication without manual intervention or additional mechanical components.
Solution Approach 2:
The patent changes the material parameter of the fastening system by replacing metal-to-metal contact with insulating material contact. This parameter change enables the incorporation of lubricating material within the insulating element's structure, transforming the lubrication system from an external applied grease layer to an integrated self-contained lubrication mechanism that persists throughout the component's service life.
3Reliability
If insulating element is added between rod and bull-horns, then galvanic corrosion is prevented, but device complexity increases
Solution Approach 1:
The insulating element is designed to perform multiple functions simultaneously: it provides galvanic isolation between dissimilar metals, serves as a structural component of the fastening assembly, and acts as a lubrication reservoir. This multi-functionality eliminates the need for separate corrosion protection components and lubrication systems, thereby preventing corrosion while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent merges previously separate functions into a single integrated insulating element. The corrosion protection function, structural support function, and lubrication delivery function are combined into one component, simplifying the overall assembly process and reducing the number of separate parts that would otherwise be needed to achieve the same protective effects.
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 insulating elements effectively reduce wear and prevent rotation blockage by minimizing galvanic corrosion and maintaining lubrication, ensuring smooth operation of the tilt mechanism.
Implementation Method 1
at least one insulating element is provided interposed between each end of the fastening rod and the corresponding housing seat... prevent galvanic corrosion
Implementation Method 2
lubricating material being interposed between the two insulating elements... facilitate smooth rotation
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
Device for fastening steering actuator cylinders to outboard marine motors, comprising a fastening rod (4) insertable inside an outboard motor, which fastening rod (4) has each of the ends (41) thereof inserted inside a corresponding housing seat (51) obtained in a terminal element (5), such that said fastening rod (4) has a relative rotation with respect to said terminal elements (5). The terminal elements are further fastened to the steering cylinder. Said outboard motor is integral with said fastening rod (4), such that said outboard motor can oscillate around the longitudinal axis of said fastening rod (4). At least one insulating element is further provided interposed between each end (41) of said fastening rod (4) and the corresponding housing seat (51), said insulating element being configured to at least partially surround the surface of each end.