Steering Shaft Brake for Haptic Feedback During Power Loss

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Solution Overview

Problem

Existing heavy vehicle steering systems, particularly those for agricultural vehicles, lack versatility in providing effective haptic feedback and fail to prevent the steering member from moving freely when not operated, especially in hydrostatic and steer-by-wire systems.

Innovation Solution

A steering system incorporating an electric motor and an electrically actuated brake, where the brake switches positions based on power availability, generates haptic feedback, and prevents unwanted steering movement, with an electronic control unit managing both components for redundancy and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electric motor is used to generate haptic feedback on the steering member, then steering feedback is improved, but the system becomes more complex and less reliable in power failure conditions

Engineering Contradiction:
Improvesteering safety in power failureVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The brake system is designed to automatically engage and provide braking torque when electrical power is lost, without requiring external control signals. The spring-loaded brake mechanism self-activates in response to power failure, ensuring continuous steering safety through passive mechanical action rather than active electrical control.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of using an electric motor to provide both steering actuation and haptic feedback (which fails in power outages), the invention inverts the approach by using a spring-loaded brake that passively provides feedback and safety through mechanical means when electrical power is unavailable.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If a spring-loaded brake is used to provide haptic feedback and prevent unwanted steering movement, then reliability in power failure is improved, but the device becomes more complex

Engineering Contradiction:
Improvesteering control in power failureVSAvoidbrake mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into a single brake mechanism: it provides haptic feedback to the operator, prevents unwanted steering movement, and acts as a safety device in power failure conditions. This consolidation eliminates the need for separate systems for each function, reducing overall complexity while improving reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring-loaded brake is designed to perform multiple functions simultaneously: generating braking torque for steering control, providing haptic feedback to the operator, and serving as a safety mechanism during power failures. This multi-functionality reduces the need for additional separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Force

If the brake generates greater torques than the motor, then steering safety and feedback effectiveness are improved, but the brake mechanism becomes more complex

Engineering Contradiction:
Improvebraking torqueVSAvoidbrake mechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The spring-loaded brake is pre-configured with sufficient spring force to generate greater torques than the electric motor can produce. This preliminary preparation ensures that when the brake engages, it immediately provides superior braking force for safety and feedback purposes, without requiring complex control mechanisms to modulate torque output.

Inventive Principle:
Principle #10Preliminary action

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 system provides a compact, cost-effective, and redundant haptic feedback mechanism, ensuring safe steering even in power failures by using a brake to generate greater torques than the motor, preventing unwanted steering movement and indicating end-of-stroke limits.

Implementation Method 1

at least one electrical winding, adapted to be crossed by an electric current to generate an electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Implementation Method 2

one elastic element configured to push the third portion against the second portion and to generate an elastic force in the direction of moving the third portion away from the electrical winding and bringing the second portion closer to the contact surface

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP4023529B1Steering system
Publication Date: 2025.10.01 OGNIBENE POWER
  • EP4023529B1 patent drawingFigure 1
  • EP4023529B1 patent drawingFigure 2

AI summary

The invention relates to a steering system (15) comprising: a shaft (45) rotatable with respect to an axis of rotation (R), a steering member (40) connected to the shaft to drive it in rotation with respect to said axis of rotation (R), an electric motor (65) configured to generate and apply a torque on the shaft (45), and a brake (125) operable between a first position, in which it generates a braking torque on the shaft (45), and a second position, in which it does not generate a braking torque on the shaft (45).