Steer-by-Wire Steering Shaft Rheological Fluid Solidification

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Solution Overview

Problem

Conventional steer-by-wire steering devices face challenges in easily changing the maximum rotational angle of the steering wheel, suffer from noise issues due to mechanical contact, and have durability concerns with the nut and stopper mechanism.

Innovation Solution

A steer-by-wire steering device incorporating a steering shaft with a wing portion, a housing containing rheological fluid, and an electronic control unit that solidifies the fluid to restrict rotation when a predetermined angle is reached, allowing for adjustable maximum rotational angles and reduced noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a nut and stopper mechanism is used to restrain steering wheel rotation, then the maximum rotational angle is limited, but the contact surface between the nut and stopper deforms or the coupling portion is damaged over time

Engineering Contradiction:

Improvecomponent durabilityVSAvoidcontact surface integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent replaces the mechanical nut and stopper contact system with a magnetic field-based restraining system. The electronic control unit generates a magnetic field that acts on the steering shaft without physical contact, eliminating the wear and deformation issues of mechanical contact surfaces while maintaining the rotational angle limitation function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the control system and the steering shaft. This magnetic field mediator transmits the restraining force without requiring direct mechanical contact between components, thereby preventing contact surface deformation and coupling portion damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a nut and stopper mechanism is used to restrain steering wheel rotation, then the maximum rotational angle is limited, but impact sound occurs when the steering wheel reaches the maximum rotational angle

Engineering Contradiction:

Improvenoise levelVSAvoidsteering sensation quality

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent replaces the mechanical impact-based stopping mechanism with a magnetic field-based restraining system. The magnetic field gradually increases in strength as the steering wheel approaches the maximum rotational angle, providing a smooth deceleration without impact sounds, thereby improving both noise levels and steering sensation quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies magnetic field force in advance before the steering wheel reaches the maximum rotational angle. The electronic control unit detects the approaching angle and gradually strengthens the magnetic field to cushion the steering motion, preventing harsh impacts and reducing noise while maintaining reliable steering control.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If a nut and stopper mechanism is used to restrain steering wheel rotation, then the maximum rotational angle is fixed, but it is hard to change the maximum rotational angle after assembly

Engineering Contradiction:

Improveadjustability of maximum rotational angleVSAvoidstructural complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transforms the fixed mechanical stopper position into a dynamically adjustable magnetic field strength controlled by the electronic control unit. The maximum rotational angle can be changed by modifying the control parameters without any mechanical reconfiguration, enabling flexible adaptation while maintaining simple hardware structure.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent makes the steering restraint system multi-functional by combining the rotational angle limitation with electronic control capabilities. The same magnetic field mechanism can accommodate different maximum rotational angle requirements for various vehicle types and driving conditions, eliminating the need for different mechanical configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables easy adjustment of the steering wheel's maximum rotational angle, enhances driver feedback, and improves component durability by eliminating mechanical collisions and degradation.

Implementation Method 1

an electronic control unit controlling a viscosity of the rheological fluid to, if the steering angle of the steering shaft reaches a first rotational angle, solidify the rheological fluid to restrain rotation of the steering shaft

Methodology Applied

Scientific EffectRheological fluid solidification: Phase Change

Data Source

PatentUS20230024421A1Steer-by-wire steering apparatus

Publication Date: 2023.01.26 HL MANDO CORP

AI summary

According to embodiments of the present invention, the maximum rotation angle of a steering wheel can be easily changed, the steering feel provided to a driver can be enhanced by improved noise performance, and the durability of components can be improved.