Electric Outboard Motor Inverter Stacking for Steering

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Solution Overview

Problem

Existing electric outboard motors with AC motors face issues of increased moment of inertia due to heavy control units and batteries being offset from the center, leading to difficult steering operations and potential cable damage from exposed wiring.

Innovation Solution

The electric outboard motor design separates the AC motor and inverter, stacking them along the axial direction of the AC motor's rotation output axis, with the inverter positioned within the motor's outline, reducing the moment of inertia and minimizing cable exposure to prevent damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the control unit and battery are arranged at positions away from the center of steering, then the electrical connection between battery and inverter is achieved, but the moment of inertia around the steering shaft increases making steering operation difficult

Engineering Contradiction:
Improveelectrical connectionVSAvoidsteering operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The inverter is positioned in the axial direction of the AC motor rather than radially offset, utilizing the longitudinal space of the motor assembly. This dimensional repositioning allows electrical connection components to be placed away from the steering axis center while maintaining compact overall dimensions and reducing steering moment of inertia.

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

2Reliability

If the control unit is arranged on the front side of the motor, then the electrical connection is established, but the control unit projects inside of the ship compressing the space

Engineering Contradiction:
Improveelectrical connectionVSAvoidship space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The inverter is positioned within the outline of the AC motor in axial view, nesting the electrical connection component inside the motor's spatial envelope. This nesting arrangement eliminates additional space projection into the ship interior while maintaining all necessary electrical connection functions.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If wires or cables are routed in the outboard motor, then the electrical connection between battery and inverter is achieved, but the wires or cables may be touched by ship operator or foreign matter causing damage

Engineering Contradiction:
Improveelectrical connectionVSAvoidcable damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The inverter is extracted as a separate component from the motor assembly, positioned in the axial direction with minimal cable routing required. This separation reduces the length and exposure of power cables within the motor housing, minimizing opportunities for operator contact or foreign matter intrusion that could cause cable damage.

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration enhances steering operability by reducing the power required for steering and prevents cable damage, while maintaining efficient space utilization on the ship.

Implementation Method 1

an inverter that converts a direct current to an alternating current to supply the alternating current to the AC motor

Methodology Applied
Scientific EffectElectrical energy conversion:

Data Source

PatentEP2559616B1Electric outboard motor
Publication Date: 2019.01.16 SUZUKI MOTOR CORP
  • EP2559616B1 patent drawingFigure 1
  • EP2559616B1 patent drawingFigure 2
  • EP2559616B1 patent drawingFigure 3

AI summary

Provided is an electric outboard motor that includes a drive motor, which is an AC motor, as a drive source. The electric outboard motor includes: an outboard motor main body that includes the drive motor and an inverter that converters a direct current to an alternating current to supply the alternating current to the drive motor; a control/power supply unit that is formed separately from the outboard motor main body and that can supply the direct current to the inverter; and a connection cable that electrically connects the outboard motor main body and the control/power supply unit. The inverter and the drive motor are stacked and arranged in an axial direction of a rotation output axis of the drive motor. Part of the inverter falls within an outline of the drive motor in a view in the axial direction of the rotation output axis of the drive motor.