Steering Feedback Actuator Pulley Layout for Reduced Column Space

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Solution Overview

Problem

Steer-by-wire systems in motor vehicles lack mechanical feedback, making it difficult for drivers to grasp current driving situations and impairing vehicle steerability and driving safety due to the absence of haptic feedback.

Innovation Solution

A compact belt-driven feedback actuator design with coaxially or angularly arranged pulleys, allowing for a slim design that optimally utilizes the axial space in the steering column, enabling efficient torque transmission with minimal radial construction volume, and incorporating an inclined belt drive for reduced radial installation space and enhanced torque transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a belt drive with radially arranged pulleys is used for torque transmission, then smooth operation and low weight are achieved, but a large installation volume is required

Engineering Contradiction:
Improveweight of feedback actuatorVSAvoidinstallation volume
Core Design Contradiction:
Weight of moving objectVSVolume of stationary object

Solution Approach 1:

The patent transitions from a radial arrangement of pulleys (extending outward from the longitudinal axis) to an axial arrangement (stacked along the longitudinal axis). This dimensional reorganization allows the belt drive to utilize the longitudinal space within the steering column rather than requiring radial space, thereby reducing the installation volume while maintaining the weight advantages of belt drive technology.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If a belt drive with radially arranged pulleys is used for torque transmission, then smooth operation and low weight are achieved, but the structural integration into steering column is impaired

Engineering Contradiction:
Improvestructural integrationVSAvoidinstallation volume
Core Design Contradiction:
Ease of manufactureVSVolume of stationary object

Solution Approach 1:

By reconfiguring the pulley arrangement from radial to axial, the patent enables the belt drive components to be stacked vertically along the longitudinal axis of the steering column. This allows for compact integration within the limited space of the steering column housing, improving ease of manufacture and assembly while reducing the overall installation volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If conventional mechanical steering systems are used, then direct physical feedback is provided, but mechanical coupling complexity increases

Engineering Contradiction:
Improvedriver feedbackVSAvoidmechanical coupling
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical coupling of conventional steering systems with an electric motor-driven belt drive system. The electric motor generates feedback torque that is transmitted through the belt drive to the steering shaft, providing haptic feedback to the driver without requiring direct mechanical coupling between the wheels and steering wheel. This substitution reduces mechanical complexity while maintaining reliable driver feedback.

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 solution provides a compact, lightweight, and low-noise feedback actuator that enhances driver feedback, improving steerability and safety by mimicking the haptic responses of conventional mechanical steering systems while maintaining the advantages of belt drives such as smooth operation and low weight.

Implementation Method 1

a belt drive, which has at least one pair of pulleys with two pulleys wrapped by a belt

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4185510B1Feedback actuator for a steering device of a motor vehicle and steering column for a motor vehicle
Publication Date: 2024.09.11 THYSSENKRUPP PRESTA AG
  • EP4185510B1 patent drawingFigure 1~2
  • EP4185510B1 patent drawingFigure 3
  • EP4185510B1 patent drawingFigure 4

AI summary

The present invention relates to a feedback actuator (7) for a steering device of a motor vehicle, comprising a steering shaft (4) which is mounted rotatably about a longitudinal axis (L) extending in the longitudinal direction and which is coupled so as to be driveable in rotation to the motor shaft (72) of an electric motor (71) via a belt drive (8, 9) which has at least one belt pulley pair with two belt pulleys (81, 82, 91, 92), around which a belt (83, 93) is looped and of which one is operatively connected to the motor shaft (72) and one is operatively connected to the steering shaft (4). In order to enable an optimized design with a smaller construction volume, the invention proposes that the two belt pulleys (81, 82, 91, 92) of the belt pulley pair are arranged coaxially with each other or at an angle to each other.