Outboard Motor Shift Actuator Using Radial Movement
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Solution Overview
Problem
Existing shift actuators for outboard motors face challenges in miniaturization due to the need for a large movable region along the propeller shaft, which is often not feasible given the space constraints in the gearshift case, leading to potential inefficiencies in motor power transmission and gear change response.
Innovation Solution
A shift actuator design featuring a main body section with an electric motor and a gear mechanism that includes a threaded shaft and movable nut, allowing the electric motor's rotating shaft to rotate the shaft section, which moves a shift member to change gears without requiring extensive axial movement along the propeller shaft, thus reducing the necessary movable region and enabling compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the electric motor is arranged near the propeller shaft to improve transmission efficiency and reduce actuator length, then transmission efficiency and miniaturization are improved, but a sufficiently large movable region cannot be secured in the gearshift case
Solution Approach 1:
The invention changes the movement direction from axial (along the propeller shaft) to radial (perpendicular to the propeller shaft). The shift rod moves in a direction perpendicular to the propeller shaft's longitudinal direction, allowing the electric motor to be positioned near the propeller shaft while still providing sufficient movement space within the gearshift case.
2Manufacturing precision
If the shift rod length is reduced by positioning the electric motor near the shift slider, then transmission accuracy and miniaturization are improved, but the movable region becomes insufficient
Solution Approach 1:
The shift rod's movement direction is changed to be perpendicular to the propeller shaft's longitudinal direction. This dimensional change allows the shift rod to be shorter along the propeller shaft axis while still providing adequate movement range, as the movement now occurs in a radial direction where space is available.
3Volume of moving object
If the shift actuator is made compact by reducing movable region, then miniaturization is improved, but the shift rod cannot sufficiently slide the shift slider
Solution Approach 1:
By changing the shift rod's movement direction to perpendicular to the propeller shaft's longitudinal direction, the invention creates sufficient movement space within a compact actuator volume. The radial movement path provides adequate stroke length without requiring extended axial space.
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 design enhances miniaturization, improves transmission efficiency and accuracy, and reduces power loss by allowing the electric motor to be positioned closer to the shift member, while maintaining effective gear change functionality.
Implementation Method 1
The shaft section has a threaded shaft and a movable nut. The threaded shaft extends parallel to the rotating shaft of the electric motor. The threaded shaft rotates in conjunction with the rotating shaft of the electric motor, because of the gear mechanism. The movable nut is screwed on the threaded shaft. The movable nut moves upward or downward with rotation of the threaded shaft.
Data Source
AI summary
According to one embodiment, a shift actuator includes a main body section and a shaft section. The main body section has an electric motor which has a vertically extending rotating shaft, and a gear mechanism which rotates the shaft section in accordance with the rotating shaft. The shaft section has a threaded shaft extending parallel to the rotating shaft and made to rotate by the gear mechanism in accordance with the rotating shaft and a movable nut which is screwed onto the threaded shaft and moves upward or downward with rotation of the threaded shaft. The movable nut is connected with a shift member which changes the gears of a propeller shaft.