Marine Propulsion Unit Wire Routing for Steering Angle

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Solution Overview

Problem

Existing marine propulsion units constrain the steering angle of ducts due to large torsional and bending stresses on power supply wires and signal wires, which limits their steering capability.

Innovation Solution

The power supply wires and signal wires are routed along the casing outside and in front of the steering shaft, wound in an arcuate shape with a large radius, and introduced obliquely through a hole to reduce torsional and bending stresses, allowing for a larger steering range without constraining the duct's angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If power supply wires and signal wires are directly inserted into the steering shaft, then the wiring structure is simple, but large torsional and bending stresses occur on the wires when the duct is steered, constraining the steering angle

Engineering Contradiction:
Improvewiring structureVSAvoidsteering angle
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The power supply wires and signal wires are extracted from the steering shaft interior and routed along the exterior surface of the steering shaft. This extraction eliminates the constraint where wires inserted into the steering shaft would experience large torsional and bending stresses during steering, thereby removing the limitation on steering angle while maintaining wiring simplicity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The wires are arranged in an arcuate pattern along the rotational direction of the steering shaft, transitioning from a radial insertion configuration to a circumferential routing configuration. This dimensional change allows the wires to follow the rotational movement of the steering shaft, reducing torsional stress and enabling greater steering angles

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

2Reliability

If power supply wires and signal wires are routed along the casing outside the steering shaft in an arcuate shape, then torsional deformation and bending stresses on the wires are reduced, but the wiring path becomes more complex

Engineering Contradiction:
Improvewire stress resistanceVSAvoidwiring path
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wires are routed in an arcuate shape along the exterior surface of the steering shaft, following the curvature of the shaft's rotation. This curved routing allows the wires to accommodate the rotational movement of the steering shaft, significantly reducing torsional deformation and bending stresses while the complexity is managed by the natural cylindrical geometry of the steering shaft

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If the duct is steered with a large steering angle, then the steering capability is improved, but large torsional stresses occur on the power supply wires and signal wires

Engineering Contradiction:
Improvesteering capabilityVSAvoidwire stress
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

By extracting the wires from the steering shaft interior and routing them along the exterior, the system enables large steering angles without subjecting the wires to excessive torsional stresses, thereby improving steering capability while maintaining wire integrity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The wiring configuration is designed to dynamically accommodate the steering motion, with the arcuate routing allowing the wires to flex and follow the rotational movement of the steering shaft, enabling adaptive response to varying steering angles without exceeding stress limits

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3842332B1Marine propulsion unit
Publication Date: 2024.10.09 YAMAHA MOTOR CO LTD
  • EP3842332B1 patent drawingFigure 1
  • EP3842332B1 patent drawingFigure 2
  • EP3842332B1 patent drawingFigure 3~4

AI summary

A marine propulsion unit (100) includes a casing (7) configured to house a steering shaft (5) and a controller (70) configured or programmed to control driving of a propeller (4), a power supply wire (90), and a signal wire (91). The power supply wire and the signal wire are located outside and along the casing so as to pass in front of the steering shaft along a rotation direction of the steering shaft from a first side of the casing to a second side of the casing in a right-left direction in a plan view.