Outboard Motor Steering Shaft Nesting

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Solution Overview

Problem

Conventional outboard motors increase the size and length of boats due to the positioning of the steering shaft forward of the drive shaft, requiring larger boat bodies to maintain stability, which is inefficient and increases frictional resistance during steering.

Innovation Solution

The outboard motor design incorporates a support member with an upper and lower support that surrounds the drive shaft, coupled by a coupler, bringing the steering axis and drive shaft closer together, reducing the boat's length and size, and utilizing a damper to minimize vibration transfer and friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the steering shaft is arranged at a position spaced forward of the drive shaft, then the outboard motor can be steered, but the entire length of the boat is increased

Engineering Contradiction:
Improvesteering capabilityVSAvoidentire length of boat
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The support member is configured to surround the drive shaft, with the steering shaft arranged within or alongside the drive shaft assembly. This nesting arrangement allows the steering shaft to be positioned close to the drive shaft without interfering with its function, thereby reducing the overall length of the outboard motor and the boat while maintaining steering capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of positioning the steering shaft forward along the longitudinal axis of the drive shaft, the invention repositions it in a different spatial arrangement - surrounding or adjacent to the drive shaft in a radial or lateral dimension. This dimensional change allows both shafts to coexist in a compact configuration, reducing the boat's length while preserving steering functionality.

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

2Ease of operation

If the steering shaft is arranged forward of the drive shaft, then steering is enabled, but the center of gravity moves rearwardly away from the boat body, requiring increased floatation

Engineering Contradiction:
Improvesteering capabilityVSAvoidcenter of gravity position
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

By nesting the steering shaft within or alongside the drive shaft assembly, the mass distribution of the outboard motor is concentrated closer to the boat body. This compact arrangement prevents the center of gravity from shifting rearwardly, eliminating the need for increased boat floatation while maintaining steering capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Repositioning the steering shaft in a different spatial dimension - surrounding or adjacent to the drive shaft rather than forward of it - changes the mass distribution of the outboard motor. This dimensional repositioning keeps the center of gravity closer to the boat body, avoiding the need for additional floatation.

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

3Ease of operation

If the outboard motor body is supported by an entire steering shaft, then steering is achieved, but frictional resistance during steering is increased

Engineering Contradiction:
Improvesteering functionVSAvoidfrictional resistance
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The support member is divided into an upper support portion and a lower support portion that are spaced apart along the drive shaft. This segmentation allows the outboard motor body to be supported at multiple discrete points rather than along the entire length, reducing contact friction while maintaining stable support and steering function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support structure transitions from a single-point support at the end of a long steering shaft to a distributed support system with upper and lower support portions surrounding the drive shaft. This dimensional change in the support configuration reduces the contact area and frictional resistance while maintaining steering capability.

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

Data Source

PatentEP3266699B1Outboard motor
Publication Date: 2019.11.27 YAMAHA MOTOR CO LTD
  • EP3266699B1 patent drawingFigure 1
  • EP3266699B1 patent drawingFigure 2
  • EP3266699B1 patent drawingFigure 3~4

AI summary

An outboard motor (100) includes an outboard motor body (100a), a mounting member (81) mounted on a boat body (11), and a support member (8a) that supports the outboard motor body so as to be steerable with respect to the mounting member. The support member includes an upper support (82) that surrounds a drive shaft (21) and supports the outboard motor body, a lower support (85) that is spaced downward from the upper support, surrounds the drive shaft, and supports the outboard motor body, and a coupler (84) that couples the upper support to the lower support.