Marine Steering Actuator Layout for Reliable Rotary-to-Linear Drive

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Solution Overview

Problem

Existing electric actuators for marine steering systems face challenges in efficiently translating rotational motion into linear reciprocating motion while maintaining structural integrity and operational reliability.

Innovation Solution

The electric actuator comprises a housing with a reciprocating output shaft, a rotor coupled to the output shaft, a motor with an output shaft parallel to the electric actuator's output shaft, and a drive mechanism, such as a belt or idler gear, to transmit rotational motion. Additionally, a position sensor and a clutch/brake mechanism are integrated for precise control and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a belt drive mechanism is used to couple the motor output shaft to the rotor, then the device complexity is reduced and ease of manufacture is improved, but the transmission precision and reliability may be affected by belt tension and wear

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a tensioned belt drive mechanism where the belt is intentionally tensioned to maintain optimal contact and prevent slippage. The tensioning parameter is controlled to balance between sufficient friction for power transmission and minimal wear, thereby maintaining reliability while using the simpler belt drive system

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The belt acts as an intermediary element between the motor output shaft and the rotor. This intermediary allows for smooth power transmission with reduced mechanical stress and vibration, improving reliability while maintaining the simplicity and manufacturability of the belt drive system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If an idler gear mechanism is used to couple the motor output shaft to the rotor, then the transmission reliability is improved through positive gear engagement, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
ImprovereliabilityVSAvoidease of manufacture
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The idler gear mechanism segments the power transmission path into distinct engagement zones, with the idler gear acting as an intermediate component that positively engages with both the motor output shaft gear and the rotor gear. This segmentation ensures reliable power transmission while allowing each gear component to be manufactured separately using standard gear manufacturing processes

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The idler gear serves as a mechanical intermediary that provides positive engagement for reliable power transmission. By introducing this intermediate gear element, the system achieves dependable tooth-to-tooth contact while the modular gear design maintains reasonable manufacturability through standardized gear cutting and assembly procedures

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the motor output shaft is positioned parallel to the electric actuator output shaft with a radial drive mechanism, then the structural compactness is improved, but the transmission of rotational motion to linear reciprocating motion becomes more complex

Engineering Contradiction:
Improvevolume of moving objectVSAvoiddevice complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The drive mechanism utilizes a radial arrangement where the motor output shaft is positioned perpendicular to the electric actuator output shaft, creating a two-dimensional power transmission layout. This spatial arrangement allows the drive mechanism (belt or gear) to engage radially, achieving compact packaging while the reciprocating mechanism converts the rotational motion from the radial drive into linear motion along the actuator output shaft axis

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

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 configuration enables efficient and reliable conversion of rotational motion to linear motion, enhancing the actuator's performance and durability in marine steering applications. The integrated position sensor ensures precise steering control, while the clutch/brake mechanism provides safety and operational flexibility.

Implementation Method 1

There is a motor disposed within the housing. The motor has an output shaft coupled to the rotor.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3672868B1Electric actuator for a marine steering system
Publication Date: 2025.04.30 DOMETIC MARINE CANADA INC
  • EP3672868B1 patent drawingFigure 1
  • EP3672868B1 patent drawingFigure 2
  • EP3672868B1 patent drawingFigure 3

AI summary

An electric actuator for a marine steering system comprises a housing and an output shaft reciprocatingly received by the housing. There is a rotor disposed within the housing. The rotor is coupled to the output shaft of the electric actuator. Rotation of the rotor causing the output shaft of the electric actuator to reciprocate relative to the housing. There is a motor disposed within the housing. The motor has an output shaft coupled to the rotor. A longitudinal axis of the output shaft of the motor is parallel with a longitudinal axis of the output shaft of the electric actuator. There is also a drive mechanism disposed within the housing. The drive mechanism couples the output shaft of electric actuator to the rotor. The drive mechanism is on a plane radial to a longitudinal axis of the output shaft of the motor.