Marine Propulsion Drive Source Switching for Smooth Gear Meshing
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Solution Overview
Problem
Existing marine propulsion devices with both internal combustion engines and electric motors face challenges in smoothly switching between drive sources due to space constraints and synchronization issues, leading to potential noise and excessive load on actuators during gear meshing.
Innovation Solution
A drive source switching system with a controller that manages the movement of driven members to ensure smooth engagement and disengagement with driving members, temporarily interrupting switching attempts when alignment issues occur to prevent collisions and reduce load on actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a synchronizing mechanism is installed to synchronize the number of revolutions of protrusions with the gear, then smooth meshing between protrusions and gear is achieved, but there is not enough space in the marine propulsion device due to retrofit constraints
Solution Approach 1:
The patent extracts the synchronizing function from a separate mechanical synchronizing mechanism and integrates it into the control system through rotational speed control. The controller adjusts the rotational speed of the electric motor to synchronize it with the internal combustion engine, eliminating the need for a physical synchronizing mechanism and freeing up space in the retrofitted marine propulsion device.
Solution Approach 2:
The patent replaces the mechanical synchronizing mechanism with an electronic control system. Instead of using mechanical components to physically synchronize the rotation, the controller uses electrical signals to adjust the electric motor's rotational speed, matching it with the internal combustion engine's speed before engagement. This substitution eliminates complex mechanical structures and reduces space requirements.
2Ease of operation
If taper processing is applied to the edges of protrusions and gear edges to facilitate meshing, then meshing is improved, but the strength of protrusions and gear edges is reduced
Solution Approach 1:
The patent changes the operational parameters (rotational speed) instead of modifying the physical geometry (taper processing). By adjusting the rotational speed of the electric motor to match the internal combustion engine before engagement, the system achieves smooth meshing without altering the shape or reducing the strength of the protrusions and gear edges.
Solution Approach 2:
The controller performs preliminary synchronization by adjusting the rotational speed of the electric motor to match the internal combustion engine's speed before the engagement occurs. This preliminary speed matching ensures that when the protrusions and gear edges engage, they do so without collision or shock, eliminating the need for taper processing that would compromise structural integrity.
3Reliability
If the actuator continues to move the shift slider for multiple attempts to mesh protrusions and gear, then meshing may eventually succeed, but a large load is applied to the actuator motor
Solution Approach 1:
The controller performs preliminary speed synchronization by adjusting the electric motor's rotational speed to match the internal combustion engine's speed before engagement. This preliminary action ensures that when the shift slider moves the protrusions toward the gear, both components are already synchronized, enabling successful meshing on the first attempt and avoiding repeated engagement attempts that would overload the actuator motor.
Solution Approach 2:
The controller uses feedback from speed sensors to monitor the rotational speeds of both the internal combustion engine and electric motor, continuously adjusting the electric motor's speed to maintain synchronization. This feedback mechanism ensures that speed matching is achieved and maintained throughout the engagement process, preventing failed meshing attempts and reducing actuator load.
4Volume of moving object
If miniaturization of protrusions and motor driven gear is performed for electric motor retrofit, then space is saved, but the strength and durability of meshing components are reduced
Solution Approach 1:
The patent changes the operational parameter (rotational speed synchronization) instead of relying on larger component dimensions for strength. By ensuring precise speed matching between the electric motor and internal combustion engine before engagement, the system enables miniaturized protrusions and gear components to mesh smoothly without collision, maintaining their structural integrity despite reduced size.
Solution Approach 2:
The controller performs preliminary speed synchronization to ensure that when miniaturized protrusions and gear components engage, they do so without shock or collision. This preliminary speed matching protects the weakened, miniaturized components from damage that would otherwise result from their reduced size and strength.
Data Source
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AI summary
A drive source switching system for a marine propulsion device, includes a first drive source, a second drive source, a propeller shaft, a first driving member, a second driving member, a first driven member and a second driven member that are movable in an axial direction of the propeller shaft, and a controller. The first driven member transmits a drive force generated by the first drive source to the propeller shaft when engaged with the first driving member. The second driven member transmits a drive force generated by the second drive source to the propeller shaft when engaged with the second driving member. In a case that the controller moves the first driven member that is not engaged with the first driving member toward the first driving member, the controller moves back the first driven member when the first driven member fails to be engaged with the first driving member.