Outboard Motor Tilt Control Using Triaxial Sensors

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Solution Overview

Problem

Conventional outboard motors require manual measurement of mounting angles, leading to increased workload and error in detecting propeller shaft tilt angles, due to the reliance on attitude angle sensors installed on the hull.

Innovation Solution

Integration of triaxial acceleration and angular velocity sensors within the outboard motor body, coupled with a controller that adjusts the tilting mechanism to accurately detect and correct tilt angles of propeller and drive shafts relative to gravity, traveling, and horizontal directions, eliminating the need for manual angle measurement and reducing detection errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If attitude angle sensors are installed on the hull to detect tilt angles, then the detection function is provided, but manual measurement of mounting angles is required and detection accuracy deteriorates due to cumulative errors

Engineering Contradiction:

Improveworkload for manual angle measurementVSAvoiddetection accuracy of propeller shaft tilt angle

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces the outboard motor body as an intermediary carrier for the attitude angle sensors. Instead of installing sensors directly on the hull, they are mounted on the outboard motor body which itself is mounted on the hull. This intermediary structure allows the sensors to directly measure the tilt angles of the propeller shaft and drive shaft without requiring separate manual measurement of the outboard motor mounting angle, thereby eliminating cumulative measurement errors and reducing user workload.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If manual measurement of mounting angle is performed, then the outboard motor can be installed, but user workload increases and time is consumed

Engineering Contradiction:

Improveease of outboard motor installationVSAvoidtime for manual angle measurement

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The patent implements self-service by having the outboard motor body automatically perform the angle measurement function through integrated attitude angle sensors. The sensors mounted on the outboard motor body automatically detect the tilt angles during installation and operation, eliminating the need for users to manually measure and calculate mounting angles. This self-measuring capability significantly reduces installation time and user workload while maintaining ease of installation.

Inventive Principle:

Principle #25Self-service

3Reliability

If sensors are installed on the hull to detect tilt angles, then the detection function is provided, but detection accuracy deteriorates due to error accumulation from multiple measurement steps

Engineering Contradiction:

Improvedetection function availabilityVSAvoiddetection accuracy of tilt angle

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent extracts the angle measurement function from the hull-based detection system and relocates it to the outboard motor body. By taking out the attitude angle sensors from the hull installation context and mounting them directly on the outboard motor body, the system eliminates the need for separate measurement of the outboard motor mounting angle. This extraction reduces the number of measurement steps from two (hull angle + motor mounting angle) to one (direct motor body angle), thereby reducing error accumulation while maintaining reliable detection functionality.

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 solution reduces user workload, enhances detection accuracy of tilt angles, and ensures stable propulsion by aligning propeller shafts with optimal directions, minimizing thrust loss and preventing unstable vessel operation.

Implementation Method 1

acquire at least one of a gravity direction, a traveling direction, and a horizontal direction of the hull using the triaxial acceleration sensor

Methodology Applied

Scientific EffectGravity: Gravitation

Implementation Method 2

detect at least one of the tilt angle of the drive shaft with respect to the gravity direction, the tilt angle of the propeller shaft with respect to the traveling direction, and the tilt angle of the propeller shaft with respect to the horizontal direction using the triaxial angular velocity sensor

Methodology Applied

Scientific EffectAngular velocity sensing: Gyroscope

Data Source

PatentUS11267547B2Outboard motor and marine vessel

Publication Date: 2022.03.08 YAMAHA MOTOR CO LTD

AI summary

An outboard motor includes an engine, and a propeller driven by the engine via a drive shaft and a propeller shaft, a tilting mechanism that changes a tilt angle of the propeller shaft and/or the drive shaft, a triaxial acceleration sensor and a triaxial angular velocity sensor, and a controller. The controller is configured to acquire at least one of a gravity direction, a traveling direction, or a horizontal direction of the hull using the triaxial acceleration sensor, and detect at least one of a first angle of the drive shaft with respect to the gravity direction, a second angle of the propeller shaft with respect to the traveling direction, or a third angle of the propeller shaft with respect to the horizontal direction using the triaxial angular velocity sensor, to thereby control the tilting mechanism to adjust the tilt angle of the drive shaft and/or the propeller shaft.