Steer-by-Wire Screw Mechanism for Steering Reaction Force

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Solution Overview

Problem

Steer by wire type steering systems lack mechanical connection between the steering wheel and vehicle wheels, leading to reduced driver steering feel and stability, and fail to generate steering reaction force when motor or electronic control devices malfunction.

Innovation Solution

A steer by wire type steering apparatus featuring a screw shaft with an outer screw portion and a moving member with a radially protruding guide portion, housed in a guide groove, which prevents further rotation of the steering wheel at maximum vehicle wheel rotation and generates a physical steering reaction force through sensors and motors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a steer by wire type steering system is used to eliminate mechanical connection between steering wheel and vehicle wheels, then steering convenience and control precision are improved, but driver steering feel and steering stability deteriorate due to inability to provide mechanical reaction force

Engineering Contradiction:

Improvesteering convenienceVSAvoidsteering stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A reaction force generation mechanism is introduced as an intermediary component between the steering wheel and the driver. This mechanism includes a reaction force generator that converts motor torque into a physical reaction force, which is then transmitted to the steering wheel through a transmission mechanism, restoring the tactile feedback that was lost in pure electronic steering systems

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional direct mechanical connection between steering wheel and wheels with an electronic control system that uses sensors, motors, and control units to achieve steering control, thereby improving precision while managing the trade-off through artificial reaction force generation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If the steering wheel is allowed to rotate indefinitely in steer by wire system, then steering range is increased, but steering feeling is reduced due to lack of mechanical stopping point

Engineering Contradiction:

Improvesteering rangeVSAvoidsteering feeling

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A rotation limiting mechanism is built into the steering system that preemptively prevents the steering wheel from rotating beyond its maximum intended angle. This mechanism includes mechanical stops or electronic limits that activate before excessive rotation occurs, maintaining proper steering feeling by providing definite rotational boundaries

Inventive Principle:

Principle #9Preliminary anti-action

3Extent of automation

If motor or electronic control device malfunctions in steer by wire system, then automation is improved, but steering reaction force generation fails, deteriorating driver steering feel

Engineering Contradiction:

Improveelectronic control capabilityVSAvoidsteering reaction force generation

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent incorporates backup mechanisms and redundant systems that are prepared in advance to handle motor or electronic control failures. This may include alternative reaction force generation methods, mechanical fallback systems, or redundant actuators that can take over if the primary electronic control system fails

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The steering system incorporates sensors and control units that continuously monitor the state of the motor and electronic control devices. When a malfunction is detected, the feedback loop triggers appropriate responses such as activating backup systems or alerting the driver, ensuring continuous steering reaction force generation capability

Inventive Principle:

Principle #23Feedback

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

Enhances driver steering feel and stability by mechanically limiting steering wheel rotation and providing a physical steering reaction force even in case of motor or electronic control device failures.

Implementation Method 1

a screw shaft having an outer screw portion formed on an outer circumferential surface and rotating in association with a steering shaft, a moving member having an inner screw portion corresponding to the outer screw portion formed on the inner circumferential surface, coupled to the outer circumferential surface of the screw shaft, moving in the axial direction when the screw shaft is rotated

Methodology Applied

Scientific EffectScrew mechanism: Screw

Data Source

PatentUS20230040073A1Steer by wire type steering apparatus

Publication Date: 2023.02.09 HL MANDO CORP

AI summary

A steer by wire type steering apparatus according to the embodiments of the present disclosure may comprise a screw shaft having an outer screw portion formed on an outer circumferential surface and rotating in association with a steering shaft, a moving member having an inner screw portion corresponding to the outer screw portion formed on the inner circumferential surface, coupled to the outer circumferential surface of the screw shaft, moving in the axial direction when the screw shaft is rotated, and provided with a radially protruding guide portion on the outer circumferential surface, and a housing provided with a guide groove in which the guide portion is inserted and supported on an inner circumferential surface.