Electrically Assisted Hydraulic Steering System for Marine Craft
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Solution Overview
Problem
Existing power steering systems for vehicles, particularly marine craft, face inefficiencies due to parasitic losses, high costs, complex installations, and lack of programmability, often requiring high manual effort and involving expensive components like pumps, motors, and hoses.
Innovation Solution
An electrically assisted hydraulic steering system that integrates an electric power steering (EPS) system with a hydraulic pump and a remotely located fluid reservoir, utilizing a gear set and nut-piston configuration to reduce manual steering effort, with a controller providing programmable assist and feedback features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a hydraulic pump running via a belt off the main propulsion engine is used, then steering effort is reduced when high pressure is needed, but parasitic losses occur due to continuous running and high investment cost results from many extra parts
Solution Approach 1:
The hydraulic pump operates periodically only when steering assistance is needed, rather than running continuously. The controller activates the pump based on steering torque sensor input, eliminating parasitic losses during normal operation while providing power assistance when required.
Solution Approach 2:
The patent replaces the mechanical belt-driven pump system with an electrically controlled hydraulic pump. This substitution eliminates the need for a belt connection to the propulsion engine, reducing mechanical parasitic losses while maintaining the hydraulic power assistance function.
2Force
If an electro-hydraulic system with a small electric motor and pump is used, then steering assistance is provided, but high installation cost and high installation weight result from extra parts
Solution Approach 1:
The patent merges the electric motor, hydraulic pump, fluid reservoir, and control electronics into an integrated steering system. This consolidation eliminates the need for separate mounting structures and connections, reducing overall installation weight while providing complete electro-hydraulic steering assistance.
3Force
If traditional hydraulic systems with hoses and connectors are used, then power steering is achieved, but high installation cost and complex installation result from extra part inventory
Solution Approach 1:
The patent segments the hydraulic system into modular components with integrated mounting structures. The pump assembly includes built-in fluid distribution manifolds and mounting features that eliminate the need for separate hoses and connectors, simplifying installation while maintaining power steering functionality.
4Device complexity
If a manual hydraulic pump attached to the steering wheel is used, then the system remains simple, but high effort is required to turn the wheel and vehicle
Solution Approach 1:
The patent introduces a hydraulic fluid as an intermediary between the driver's steering input and the wheel turning action. The electrically controlled pump delivers pressurized hydraulic fluid to a cylinder that amplifies the steering force, reducing the effort required while maintaining system responsiveness.
Data Source
AI summary
A steering system for a marine craft includes a steering input shaft. The steering system also includes an electric power steering (EPS) system operatively coupled to the steering input shaft, the EPS system having an electric motor that drives rotation of a system output shaft. The steering system further includes a hydraulic pump operatively coupled to the system output shaft with a gear set, the hydraulic pump having a longitudinal direction that is perpendicular to a steering input shaft axis. The steering system yet further includes a fluid reservoir located remotely relative to the hydraulic pump.