Outboard Motor Shift Device Vertical Clutch Rod Rigidity
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Solution Overview
Problem
Conventional forward/reverse shifting devices for outboard motors with electric actuators face challenges in achieving accurate shift control due to relative displacement between the clutch rod and pilot shaft, limiting the thickness and rigidity of the clutch rod, which affects the operation of the electric actuator.
Innovation Solution
A shifting device configuration for outboard motors that includes an upper unit, a lower unit, and an intermediate unit, where the electric shift actuator is positioned in the engine cover, and the clutch rod is disposed vertically behind the drive shaft, eliminating radial displacement and allowing increased thickness for enhanced rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the clutch rod thickness is increased to enhance rigidity, then the rigidity of the shift transmission mechanism is improved, but the clearance between the clutch rod and peripheral pilot shaft is reduced
Solution Approach 1:
The clutch rod is repositioned from a horizontal arrangement (passing through the pilot shaft) to a vertical arrangement (disposed behind the drive shaft). This dimensional change allows the clutch rod to achieve greater thickness for enhanced rigidity without interfering with the horizontal clearance requirements of the pilot shaft, thereby resolving the contradiction between rigidity and clearance.
2Strength
If the clutch rod thickness is increased, then the rigidity is improved, but the deflection during operation is reduced which requires larger operation amount for the electric actuator
Solution Approach 1:
By changing the clutch rod arrangement to vertical behind the drive shaft, the rod can be made thicker without increasing the radial clearance requirements. This enhanced thickness provides greater rigidity and reduces deflection, while the new positioning maintains adequate operational clearance for the electric actuator to function effectively.
3Length of moving object
If the clutch rod thickness is reduced to maintain clearance, then the clearance is secured, but the rigidity of the clutch rod is compromised
Solution Approach 1:
The invention resolves this contradiction by transitioning the clutch rod to a vertical arrangement behind the drive shaft. This allows the rod to have sufficient thickness for rigidity while maintaining the necessary clearance through its new spatial positioning, eliminating the need to compromise rigidity for clearance purposes.
Data Source
AI summary
An electric shift actuator is provided in an engine cover in which an engine of an upper unit is accommodated, a forward/reverse shift mechanism is provided in a lower unit, and a shift transmission mechanism including a clutch rod is provided to transmit driving force of the electric shift actuator to the forward/reverse shift mechanism by connecting the electric shift actuator with the forward/reverse shift mechanism, in which the clutch rod is disposed vertically in an intermediate unit on the rear side of a drive shaft that transmits driving force of the engine.