Electric Vessel Steering Linkage Decouples Rudder Shock

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Solution Overview

Problem

Hydraulic mechanisms for rudder actuation in vessels are heavy, noisy, maintenance-intensive, and prone to shock resistance issues due to direct coupling with the rudder stock, which increases complexity and cost.

Innovation Solution

An electric motor assembly with a steering linkage that transmits rotational output to the rudder, providing variable torque and decoupling from vertical movements to enhance shock resistance, with multiple motor assemblies for reduced noise and easier maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If hydraulic mechanisms are used for rudder actuation, then large forces required for rudder actuation are achieved, but the system becomes heavy, noisy, and maintenance-intensive

Engineering Contradiction:
Improverudder actuation forceVSAvoidsteering system weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent replaces the hydraulic mechanical system with an electric motor system. The electric motor assembly (32) directly or indirectly drives the rudder stock (36) through a steering linkage (34), eliminating hydraulic fluid, pumps, and associated heavy components while providing sufficient torque for rudder actuation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the hydraulic system components (hydraulic fluid, hoses, pumps, cylinders) from the steering system, replacing them with a cleaner electric motor system that eliminates the associated weight, noise, and maintenance requirements of hydraulic mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If hydraulic mechanisms are directly coupled to the rudder stock, then rudder actuation is achieved, but shock resistance deteriorates due to stress load transfer during rudder stock excursion

Engineering Contradiction:
Improverudder actuationVSAvoidshock resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a steering linkage (34) as an intermediary mechanism between the electric motor assembly (32) and the rudder stock (36). This linkage includes multiple members (drive lever, link bar, tiller) connected through joints that allow relative movement, acting as a buffer that decouples direct stress transfer during rudder stock excursion while still transmitting the necessary rotational motion for rudder actuation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the direct coupling into multiple separate linkage members (drive lever, link bar, tiller) connected by joints. This segmentation allows each component to move independently to some degree, absorbing shock and stress during rudder stock excursion rather than transferring it directly through a rigid connection.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If hydraulic mechanisms with tight tolerances are used, then precise rudder control is achieved, but vulnerability to rudder stock excursion increases

Engineering Contradiction:
Improverudder control precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a dynamic steering linkage system where the angles and lengths of linkage members can vary during operation. The joints in the linkage allow for dynamic adjustment of the mechanical advantage and motion transmission, maintaining precise rudder control while accommodating variations in rudder stock position without requiring tight tolerances throughout the entire system.

Inventive Principle:
Principle #15Dynamics

4Reliability

If components are hardened to withstand stress loads, then shock resistance is improved, but cost, weight, size, and complexity increase

Engineering Contradiction:
Improveshock resistanceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the need for hardened components by substituting the entire hydraulic system with an electric motor system. The electric motor assembly with its flexible linkage naturally accommodates shock and stress without requiring specialized hardened materials or complex protective components, thereby achieving shock resistance while reducing overall system complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The electric motor-based steering system offers lighter, quieter, and more maintainable operation with improved shock resistance, reducing maintenance costs and complexity while matching varying torque requirements for rudder control.

Implementation Method 1

an electric motor assembly (32) for generating a rotational output

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP2074023B1Steering system and an associated vessel
Publication Date: 2012.07.04 NORTHROP GRUMMAN SYSTEMS CORP
  • EP2074023B1 patent drawingFigure 1
  • EP2074023B1 patent drawingFigure 2
  • EP2074023B1 patent drawingFigure 3

AI summary

A steering system for a vessel is provided. The steering system includes an electric motor assembly and a steering linkage for transmitting the rotational output of the electric motor assembly to the vessel's rudder. The steering system may include at least three linkage members. The steering system may provide a variable output torque that corresponds at least partially with the variable required torque of the rudder at different rudder angles. The steering system may partially decouple the electric motor assembly from vertical movements in the rudder. Embodiments may include additional motor assemblies and steering linkages. The additional motor assemblies and steering linkages may provide an opposing force to reduce flutter within the system and/or be used to reduce the load of any one electric motor assembly.