Outboard Motor Layout With Low-Mounted Drive Source

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Solution Overview

Problem

Existing outboard motors struggle to keep the drive source sufficiently low with respect to the hull, which hinders a good external appearance, effective space utilization, and noise reduction.

Innovation Solution

The outboard motor design positions the drive source below the decelerator, with parallel first and second drive shafts and a decelerator between them, allowing for efficient torque transmission while keeping the drive source low.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the engine is disposed above the decelerator, then the engine can be kept low with respect to the hull to some extent, but it is difficult to keep the drive source sufficiently low

Engineering Contradiction:

Improveheight of drive sourceVSAvoidexternal appearance quality

Core Design Contradiction:

Length of stationary objectVSEase of operation

Solution Approach 1:

The patent inverts the conventional arrangement by disposing the drive source below the decelerator instead of above it. This inversion allows the drive source to be positioned lower with respect to the hull, achieving both the goal of keeping the drive source sufficiently low and maintaining good external appearance.

Inventive Principle:

Principle #13The other way round (Inversion)

2Length of stationary object

If the engine is disposed above the decelerator, then the engine can be kept low with respect to the hull to some extent, but effective utilization of space above the outboard motor is hindered

Engineering Contradiction:

Improveheight of drive sourceVSAvoidusable space above motor

Core Design Contradiction:

Length of stationary objectVSVolume of stationary object

Solution Approach 1:

By inverting the arrangement to place the drive source below the decelerator, the space above the outboard motor becomes available for other uses, such as mounting accessories or improving hull integration, while the drive source achieves a sufficiently low position.

Inventive Principle:

Principle #13The other way round (Inversion)

3Length of stationary object

If the engine is disposed above the decelerator, then the engine can be kept low with respect to the hull to some extent, but engine noise reduction is difficult

Engineering Contradiction:

Improveheight of drive sourceVSAvoidengine noise

Core Design Contradiction:

Length of stationary objectVSObject-generated harmful factors

Solution Approach 1:

Placing the drive source below the decelerator positions it lower and away from the hull, which helps block and reduce the transmission of engine noise to the hull and surrounding environment.

Inventive Principle:

Principle #13The other way round (Inversion)

4Power

If parallel drive shafts with decelerator between them are used, then torque transmission is efficient, but device complexity increases

Engineering Contradiction:

Improvetorque transmission efficiencyVSAvoidtransmission mechanism complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent extracts the decelerator function into a separate, dedicated component positioned between the parallel drive shafts. This separation allows for efficient torque transmission while making the complexity manageable through modular design.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The decelerator acts as an intermediary component between the first and second drive shafts, enabling efficient torque transmission while isolating the complexity of the deceleration mechanism from the drive shafts themselves.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12234000B2Outboard motor

Publication Date: 2025.02.25 HONDA MOTOR CO LTD

AI summary

An outboard motor 10 includes a first drive shaft 26, a second drive shaft 27, and a decelerator 28. The first drive shaft 26 outputs a torque from a drive motor 25. The second drive shaft 27 is disposed parallel to the first drive shaft 26 and transmits the torque to a propeller shaft 31 to which a propeller 32 is connected. The decelerator 28 is disposed between the first drive shaft 26 and the second drive shaft 27 and transmits the torque from the first drive shaft 26 to the second drive shaft 27. The drive motor 25 is disposed below the decelerator 28.