Clutch-Limited Rear Wheel Steering for Ground-Impact Stability

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Solution Overview

Problem

Existing rear wheel steering systems in vehicles face issues with unexpected steering due to ground impact, leading to increased power consumption and reduced service life of the steering motor, as they require frequent intervention to stabilize the vehicle.

Innovation Solution

A clutch-limited rear wheel steering device that uses a clutch to limit the rotation of the input shaft before the steering motor activates, reducing unnecessary steering interventions and minimizing power consumption by limiting axial displacement of the tie rod.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the steering motor continuously intervenes to correct unexpected steering caused by ground impact, then vehicle stability is maintained, but power consumption increases and service life of the steering motor decreases

Engineering Contradiction:

Improvevehicle stabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the function of limiting unexpected steering from the steering motor and assigns it to a dedicated clutch mechanism. The clutch is specifically designed to limit axial displacement of the tie rod through engagement of friction surfaces, separating this protective function from the steering motor's primary steering control function. This reduces the steering motor's intervention frequency and extends its service life while maintaining vehicle stability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The clutch mechanism provides beforehand cushioning by being pre-positioned to limit axial displacement of the tie rod before unexpected steering occurs. The friction surfaces of the clutch are designed to engage and limit tie rod displacement during ground impact events, preventing excessive steering angles before they can affect vehicle stability. This protective action occurs automatically without requiring steering motor intervention.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the steering motor frequently intervenes to limit unexpected steering, then rear wheel steering control is maintained, but service life of the steering motor is reduced

Engineering Contradiction:

Improvesteering controlVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The clutch acts as an intermediary mechanism between the tie rod and the steering motor. It provides a mechanical limit to tie rod axial displacement through friction surface engagement, serving as a mediator that protects the steering motor from excessive loads and frequent stalling events while allowing normal steering operations to pass through to the steering motor for controlled execution.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the clutch limits axial displacement of the tie rod, then unexpected steering is reduced, but device complexity increases

Engineering Contradiction:

Improvesteering stabilityVSAvoidclutch mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The clutch mechanism utilizes parameter changes in the form of friction surface engagement to limit tie rod axial displacement. By designing the clutch with specific friction surface areas and materials, the system achieves reliable limiting of unexpected steering through controlled friction engagement. This approach provides a simple yet effective means of limiting tie rod movement without requiring complex mechanical stops or electronic control systems.

Inventive Principle:

Principle #35Parameter changes

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 device stabilizes vehicle travel on uneven roads by limiting unexpected steering angles, reducing power consumption, and extending the service life of the steering motor by minimizing unnecessary motor operations.

Implementation Method 1

The clutch comprises a first contact surface and a second contact surface. The first contact surface is configured to come into contact with the second contact surface to limit rotation of the input shaft.

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP4686640A1Clutch-limited rear wheel steering device and vehicle

Publication Date: 2026.02.04 HUAWEI DIGITAL POWER TECH CO LTD

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AI summary

This application provides a clutch-limited rear wheel steering device and a vehicle. The rear wheel steering device is configured to control steering of one or more rear wheels of the vehicle. The rear wheel steering device includes a clutch (40), an input shaft (211), and a tie rod (30). The input shaft is configured to drive the tie rod to move in an axial direction of the tie rod. Steering of the one or more rear wheels changes with axial displacement of the tie rod. The clutch is configured to be in transmission connection to a steering motor (10) and the input shaft (211). Before the steering motor rotates, the clutch is configured to limit rotation of the input shaft. In a rotation process of the steering motor, the clutch is configured to drive the input shaft to rotate with the steering motor. In this application, the clutch is used in the rear wheel steering device to limit steering of the rear wheel, to reduce frequency of intervention of the steering motor in the rear wheel steering device, thereby reducing power consumption. (Figure 3)