Ship Propulsion Machine Dual Motor Vertical Nesting
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Solution Overview
Problem
Existing ship propulsion machines with a single motor face challenges in maintaining movement when the motor fails during sailing, and adding redundant motors increases the machine's size, leading to higher water or air resistance.
Innovation Solution
A ship propulsion machine design featuring two motors, one above the other, with a power transmission device that switches power between the motors, allowing either motor to take over in case of failure, while maintaining a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two motors and a power transmission mechanism are provided in the lower part of the outboard motor to enable backup power, then the reliability of ship movement is improved, but the lower part becomes significantly larger, increasing water resistance
Solution Approach 1:
The patent relocates the power transmission mechanism from the lower part to the upper part of the outboard motor, utilizing the vertical space above the waterline. This dimensional relocation allows the lower part to remain compact for reduced water resistance, while the upper part accommodates the additional motors and transmission mechanism for reliability.
2Reliability
If two motors and a power transmission mechanism are provided in the upper part of the outboard motor to enable backup power, then the reliability of ship movement is improved, but the upper part becomes significantly larger, increasing air resistance and reducing attachment stability
Solution Approach 1:
The patent employs a nested arrangement where the drive shaft passes through the first motor shaft, and the power transmission mechanism is integrated within the vertical space between the two motors. This nesting minimizes the horizontal footprint and overall volume increase in the upper part, reducing air resistance and maintaining attachment stability.
Solution Approach 2:
The patent utilizes the vertical dimension by arranging motors and transmission components along the vertical axis rather than horizontally. This vertical stacking minimizes the horizontal expansion that would increase air resistance and affect attachment stability, while still accommodating all necessary components for reliability.
3Power
If the motor is arranged in the lower part to generate propulsive force, then the propulsion function is achieved, but adopting a large motor increases the size of the lower part, increasing water resistance
Solution Approach 1:
The patent separates the power generation function from the power transmission function by placing motors in the upper part (above waterline) and only the drive shaft and propeller in the lower part (in water). This allows large motors to be accommodated in the upper part without increasing the volume of the lower part that contacts water, thus maintaining propulsive force while reducing water resistance.
Data Source
AI summary
A ship propulsion machine includes a power unit and a drive shaft that includes a power transmission device configured to selectively transmit at least one of a first power output from a first motor shaft of a first motor and a second power output from a second motor shaft of a second motor to the drive shaft. The first motor and the second motor are arranged in an upper part of the ship propulsion machine. The first motor shaft, the second motor shaft, and the drive shaft extend vertically. The second motor is arranged above the first motor. An upper portion of the drive shaft passes through the first motor shaft to be rotatable independently of the first motor shaft and reaches a region between the first motor and the second motor. The power transmission device is arranged between the first motor and the second motor.