Marine Propulsion Assembly With Horizontal Motor for Reduced Height
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Solution Overview
Problem
Existing marine propulsion devices with vertically disposed motors have a large vertical dimension due to the axial dimension of the motor being greater than the radial dimension, leading to inefficiencies in space utilization.
Innovation Solution
The motor is disposed horizontally with its output shaft extending in the front-rear direction, and the transmission mechanisms are arranged such that the drive shaft extends vertically between the first and second transmission mechanisms, with the propeller shaft extending rearward, reducing the vertical dimension of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the motor is disposed vertically with the output shaft extending in the vertical direction, then the motor can be easily mounted and the structure is simple, but the vertical dimension of the marine propulsion device becomes large
Solution Approach 1:
The motor is rotated from a vertical orientation to a horizontal orientation, changing the dimension in which the output shaft extends. The output shaft now extends in the front-rear direction rather than the vertical direction, allowing the motor to be mounted with its axial dimension oriented horizontally. This dimensional change reduces the vertical dimension of the overall device while maintaining ease of mounting.
2Length of stationary object
If the motor is disposed horizontally with the output shaft extending in the front-rear direction, then the vertical dimension is reduced, but the transmission mechanism arrangement becomes more complex
Solution Approach 1:
The transmission mechanism is divided into two separate stages: a first transmission mechanism positioned in front of the motor and a second transmission mechanism positioned below the first. This segmentation allows each mechanism to be optimized for its specific function and position, simplifying the overall arrangement despite the horizontal motor orientation. The drive shaft extends vertically between these two mechanisms, providing a clear structural division.
Solution Approach 2:
The drive shaft acts as an intermediary element that extends vertically between the first and second transmission mechanisms, facilitating power transmission while maintaining the reduced vertical dimension. This intermediary component allows the transmission mechanisms to be positioned at different locations (front and below) while still achieving the desired power transmission to the propeller shaft.
3Ease of manufacture
If the axial dimension of the motor is greater than the radial dimension, then the motor design is standard and easy to manufacture, but the vertical dimension of the device increases when the motor is disposed vertically
Solution Approach 1:
The motor is oriented horizontally so that its axial dimension (which is naturally greater than the radial dimension) extends in the front-rear direction rather than the vertical direction. This allows the motor to maintain its standard design with axial > radial dimensions while the overall vertical dimension of the device is reduced, as the motor's larger dimension is now oriented horizontally rather than vertically.
Data Source
AI summary
A marine propulsion device includes: a motor; a drive shaft; a first transmission mechanism that transmits rotation of an output shaft of the motor to the drive shaft; a propeller shaft; a second transmission mechanism that transmits rotation of the drive shaft to the propeller shaft; and a propeller. The motor is disposed so that an extension direction of the output shaft is a front-rear direction. The first transmission mechanism is disposed in front of the motor. The second transmission mechanism is disposed below the first transmission mechanism. The drive shaft extends in a vertical direction between the first transmission mechanism and the second transmission mechanism. The propeller shaft extends rearward from the second transmission mechanism. The propeller is provided in a rear part of the propeller shaft.