Marine Actuator Tiller Alignment Reduces Torque Couples
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Solution Overview
Problem
Existing marine steering systems face inefficiencies and reduced load-carrying capacity due to torque couples that can derate the electric actuator's performance, particularly in the alignment and coupling of the output shaft and tiller, leading to reduced steering precision and mechanical advantage.
Innovation Solution
An electric actuator with a roller screw assembly and a motor that translates the output shaft axially within the housing, coupled with a tiller that maintains a line of action in the same plane as the tiller axis throughout the steering range, minimizing torque couples and enhancing mechanical advantage through a sealed and resiliently supported design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the output shaft and tiller are aligned and coupled in conventional marine steering systems, then the steering mechanism can transmit force, but torque couples are generated that reduce the electric actuator's load-carrying capacity and steering precision
Solution Approach 1:
The patent extracts and eliminates the harmful torque couples from the steering system by redesigning the output shaft and tiller alignment. The output shaft is configured to extend substantially perpendicular to the tiller axis, and the tiller is aligned substantially parallel to the propeller shaft axis, which removes the torque couples that were derating the actuator's performance while maintaining force transmission capability.
2Ease of operation
If conventional alignment methods are used for the output shaft and tiller, then the components can be coupled, but torque-induced inefficiencies and side loads reduce mechanical advantage
Solution Approach 1:
The patent applies asymmetric positioning of the output shaft relative to the tiller. Instead of conventional symmetric or parallel alignment, the output shaft extends substantially perpendicular to the tiller axis at the coupling point. This asymmetric configuration eliminates torque couples and side loads, maximizing mechanical advantage and eliminating energy losses from misalignment.
3Productivity
If the electric actuator is designed with conventional output shaft coupling, then the system can function, but torque couples derate the actuator's performance and reduce steering precision
Solution Approach 1:
The patent implements a dynamic alignment configuration where the output shaft is positioned to extend substantially perpendicular to the tiller axis, and the tiller is aligned substantially parallel to the propeller shaft axis. This dynamic geometric relationship maintains optimal force transmission while eliminating torque couples throughout the steering range of motion, thereby maximizing both steering precision and actuator performance.
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 solution improves steering precision and mechanical advantage by reducing torque-induced inefficiencies and side loads, enhancing the load-carrying capacity and reliability of the marine steering system.
Implementation Method 1
The roller screw assembly includes a plurality of rollers and a central screw received by the rollers. The rollers are rotatable about the central screw and the central screw is coupled to the output shaft.
Implementation Method 2
There is a motor disposed within the housing near the first end of the housing. The motor including a stator and a rotor. Rotation of the rotor causes the roller screw assembly to translate axially relative to rotor
Data Source
AI summary
According to at least one embodiment, an electric actuator for a marine steering system is disclosed. The electric actuator includes a housing, an output shaft, a screw assembly coupled to the output shaft, a rotor coupled to the screw assembly, and a motor configured to rotate the rotor. Rotation of the rotor causes the output shaft to translate axially relative to the housing.