Marine Propulsion Layout With Horizontal Motor for Lower Height

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Solution Overview

Problem

Existing marine propulsion devices have a large vertical dimension due to the vertical disposition of the motor, which results in inefficient space utilization.

Innovation Solution

The motor is disposed horizontally with its output shaft aligned in the front-rear direction, and the transmission mechanisms are arranged accordingly to reduce the vertical dimension, with the propeller shaft extending rearward.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

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

Engineering Contradiction:
Improvemotor mounting structureVSAvoidvertical dimension
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The motor is reoriented from a vertical disposition (output shaft extending vertically) to a horizontal disposition (output shaft extending in the front-rear direction). This dimensional change allows the motor's axial dimension to be aligned with the front-rear direction rather than the vertical direction, thereby reducing the vertical dimension of the overall marine propulsion device while maintaining structural simplicity through straightforward horizontal mounting

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Engineering Contradiction:
Improvevertical dimensionVSAvoidtransmission mechanism arrangement
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The transmission mechanism is divided into two distinct segments: a first transmission mechanism positioned in front of the motor to transmit rotation from the motor's output shaft to the drive shaft, and a second transmission mechanism positioned below the first to transmit rotation from the drive shaft to the propeller shaft. This segmentation allows each mechanism to be optimized for its specific function and position, managing the overall complexity through modular organization while achieving the reduced vertical dimension goal

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4707160A1Marine propulsion device
Publication Date: 2026.03.11 SUZUKI MOTOR CORP
  • EP4707160A1 patent drawingFigure 1
  • EP4707160A1 patent drawingFigure 2
  • EP4707160A1 patent drawingFigure 3

AI summary

A marine propulsion device (1) includes: a motor (3); a drive shaft (8); a first transmission mechanism (9) that transmits rotation of an output shaft (4) of the motor (3) to the drive shaft (8); a propeller shaft (13); a second transmission mechanism (14) that transmits rotation of the drive shaft (8) to the propeller shaft (13); and a propeller (20). The motor (3) is disposed so that an extension direction of the output shaft (4) is a front-rear direction. The first transmission mechanism (9) is disposed in front of the motor (3). The second transmission mechanism (14) is disposed below the first transmission mechanism (9). The drive shaft (8) extends in a vertical direction between the first transmission mechanism (9) and the second transmission mechanism (14). The propeller shaft (13) extends rearward from the second transmission mechanism (14). The propeller (20) is provided in a rear part of the propeller shaft (13).