Steer-by-Wire Steering Motor Lock Torque for Wheel Immobilization

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Solution Overview

Problem

Conventional steering wheel lock devices are mechanically complex, requiring significant installation space and increasing costs, and are not suitable for steer-by-wire systems, which lack the necessary space for mechanical mechanisms.

Innovation Solution

A steering control device that implements an electric steering wheel lock function by controlling a steering motor to apply lock torque when predetermined conditions are met, eliminating the need for mechanical components and simplifying the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical steering wheel lock device is used, then theft prevention function is achieved, but device complexity increases and installation space is required

Engineering Contradiction:

Improvetheft prevention functionVSAvoidmechanical mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical steering wheel lock device with an electric control system. The steering motor, which normally provides steering assistance, is controlled to generate lock torque through electronic control unit commands, eliminating the need for separate mechanical locking mechanisms while maintaining theft prevention functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The steering motor serves dual functions: it provides steering assist torque during normal operation and generates lock torque for theft prevention when commanded by the electronic control unit. This multi-functionality eliminates the need for dedicated mechanical lock components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a mechanical steering wheel lock device is used, then theft prevention function is achieved, but installation space increases

Engineering Contradiction:

Improvetheft prevention functionVSAvoidinstallation space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The mechanical lock components are replaced by utilizing the existing steering motor and its control system. The electronic control unit directs the steering motor to produce lock torque, eliminating the need for separate mechanical locking mechanisms and their associated installation space.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The theft prevention function is merged with the existing steering assist system by controlling the steering motor to serve both purposes. This integration eliminates the need for separate mechanical lock components and reduces overall system space requirements.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a mechanical steering wheel lock device is used, then theft prevention function is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvetheft prevention functionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The steering motor is designed to perform multiple functions: providing steering assistance during normal operation and generating lock torque for theft prevention. This multi-functionality eliminates the need for separate mechanical lock components, reducing part counts and manufacturing costs.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The mechanical locking system is replaced by an electronic control approach that utilizes the existing steering motor. This substitution reduces the need for additional mechanical components, assembly steps, and associated manufacturing costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 electric steering wheel lock mechanism reduces system complexity, saves installation space, and lowers costs while ensuring effective theft prevention and improved vehicle safety.

Implementation Method 1

a steering wheel lock calculating unit performs a steering wheel lock drive control for calculating a drive command so as to output a lock torque for maintaining a rotation stop state of a steering wheel by energizing the steering motor

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentUS12351252B2Steering control device

Publication Date: 2025.07.08 DENSO CORP

AI summary

A steering control device is applied to a steer-by-wire system in which a steering mechanism and a turning mechanism are mechanically separated. The steering control device applied to the steer-by-wire system controls a drive of a steering motor that functions as a reaction motor that applies reaction torque to a steering wheel. A steering wheel lock calculating unit of the steering control device performs a steering wheel lock drive control for calculating a drive command so as to output a lock torque for maintaining a rotation stop state of the steering wheel by energizing the steering motor when a predetermined condition is satisfied while a vehicle is parked or stopped. A power converter converts power supply electric power according to the drive command calculated by the steering wheel lock calculating unit and supplies the electric power to the steering motor.