Dual-Drive Outboard Motor Steering for Extended Angle Ranges

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Solution Overview

Problem

Existing outboard motors with steering mechanisms that increase the angular range of the outboard motor body require a larger size due to the increased distance the linearly moving member needs to travel, leading to a larger motor footprint.

Innovation Solution

A steering mechanism that includes a pinion and a rack, driven by both a hydraulic actuator and an electric motor, allowing the motor to switch between two steering angle ranges without changing the distance the rack moves, thereby increasing the angular range without increasing the motor's size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the angular range in which the outboard motor body is rotatable about the steering shaft is increased, then the steering capability is improved, but the size of the outboard motor is increased

Engineering Contradiction:

Improvesteering angle rangeVSAvoidoutboard motor size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent applies dynamics by making the steering mechanism switchable between two different drive modes: a first drive source for normal steering operations and a second drive source for extended steering angle ranges. This dynamic switching allows the system to adapt its mechanical configuration based on the required steering angle, enabling large angular ranges without permanently increasing the motor size.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the steering mechanism by introducing a second drive source that operates independently from the first drive source. This parameter change allows the system to achieve different steering angle ranges by selecting different drive sources, thereby increasing adaptability without proportionally increasing the physical size of the outboard motor.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the distance over which the linearly moving member is linearly moved is increased, then the angular range is increased, but the space required in the direction of linear movement is increased

Engineering Contradiction:

Improvesteering angle rangeVSAvoidspace required for linear movement

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The system dynamically switches between two drive sources based on the required steering angle. The first drive source is used for常规 steering within a standard angular range, while the second drive source is activated when larger steering angles are needed. This dynamic selection allows the system to achieve extended angular ranges without permanently increasing the linear movement space required.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The steering mechanism is segmented into two independent drive sources: a first drive source for normal operation and a second drive source for extended range operation. This segmentation allows the system to divide the steering function into two distinct operational modes, enabling large angular ranges to be achieved without requiring continuous increased linear movement space.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12365435B2Outboard motor and marine vessel

Publication Date: 2025.07.22 YAMAHA MOTOR CO LTD

AI summary

An outboard motor includes a steering mechanism switchable between a state in which a pinion is rotated by a first drive source such that an outboard motor body is steerable within a first steering angle range, and a state in which the pinion is rotated by a second drive source such that the outboard motor body is steerable within a second steering angle range different from the first steering angle range.