Outboard Motor Automatic Disengaging Clutch for Smooth Shifting
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Solution Overview
Problem
Outboard motors experience rough and damaging gear shifts, especially in conditions like weeds or mud, due to the lack of a smooth transition mechanism between forward and reverse gears, leading to wear and tear on the clutch and gear system.
Innovation Solution
An automatic electric disengaging clutch system controlled by a sensor switch, which interrupts the power transmission during shifting, allowing the clutch dog to engage gears while they are at rest, reducing wear and enabling smoother transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple dog clutch mechanism is used for connecting the propeller to the engine, then the gear case size is minimized and manufacturing cost is reduced, but gear shifting becomes rough and damaging especially in challenging water conditions
Solution Approach 1:
The system automatically disengages the clutch dog from the gear before the gear rotates into position, and re-engages it after the gear is properly positioned. This preliminary disengagement action prevents the rough impact that would occur if the clutch engaged while the gear was rotating, thereby eliminating the harmful vibrations and gear damage while maintaining the simple dog clutch mechanism
Solution Approach 2:
The system uses the existing gear rotation and position detection mechanisms to automatically control the clutch engagement timing. The sensor detects gear position and the control system automatically actuates the clutch, making the system self-regulating without requiring external intervention or complex additional components
2Loss of time
If gear shifting is performed quickly to minimize wear on dog clutch teeth, then shifting time is reduced, but the impact forces increase and can still cause damage
Solution Approach 1:
The clutch is disengaged before the gear rotation begins, allowing the gear to rotate into position without load. The clutch is then re-engaged after the gear is properly positioned. This sequence eliminates the impact force that would occur during engagement while maintaining quick shifting, as the clutch engagement happens when there is no relative motion between mating surfaces
3Use of energy by stationary object
If the clutch engages while gears are rotating to maintain continuous power transmission, then power transmission continuity is improved, but wear and tear on the clutch and gear system increases
Solution Approach 1:
The clutch is cycled between engaged and disengaged states in a periodic manner that synchronizes with the gear shifting cycle. During normal operation the clutch remains engaged for continuous power transmission, but automatically disengages during gear rotation and re-engages after positioning. This periodic disengagement eliminates wear during critical shifting moments while maintaining continuity during normal operation
Solution Approach 2:
The system maintains continuous useful action by keeping the clutch engaged during normal power transmission and only disengaging it during the brief moments when gears are rotating into position. This minimizes the total disengagement time while ensuring that all engagement actions occur under optimal conditions, thereby extending clutch life without sacrificing operational continuity
Data Source
AI summary
An outboard-motor automatic disengaging clutch system and method, providing an improved means of shifting between forward and reverse with an outboard boat motor, providing an ability to shift in circumstances where the propeller is not spinning freely, such as in weeds or mud, and providing improved shifting with less damage to gears in all circumstances. The outboard-motor automatic disengaging clutch can be built into an outboard motor, or can be later-installed as a retrofit. The outboard-motor automatic disengaging clutch provides an electric clutch controlled by a sensor switch activated and deactivated by the mechanical linkages of the outboard motor's shifting system.