Steering Wheel Rotation Limiter Using Axial Threaded Detent Travel

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Solution Overview

Problem

Existing rotation limitation modules for steer-by-wire steering systems are complex, costly, and noisy, with multiple moving components and mechanical contacts contributing to inefficiencies and potential damage to electrical wiring.

Innovation Solution

A simple and cost-effective rotation limitation module featuring a single limiter disk mounted rotationally fixed but axially displaceable on a shaft portion, guided by a thread within a housing, with detent geometries that limit rotation by axial displacement, reducing noise and mechanical stress through a compact and precise design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple moving components and mechanical contacts are used in rotation limitation modules, then rotation limitation function is achieved, but device complexity and noise increase

Engineering Contradiction:

Improverotation limitation functionVSAvoidnumber of moving components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple detent geometries and counter-detent geometries onto single housing portions and a single limiter disk, respectively. This merging of multiple limiting functions into unified components reduces the number of moving parts while maintaining the rotation limitation function in both rotation directions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The limiter disk serves multiple functions: it limits rotation in the first direction via the first detent geometry, limits rotation in the second direction via the second detent geometry, and provides axial displacement guidance through the sliding guide. This multi-functionality reduces the need for separate components for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple mechanical contacts are used for rotation limitation, then rotation control is achieved, but noise and mechanical stress increase

Engineering Contradiction:

Improverotation controlVSAvoidnoise and mechanical stress

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the rotation limitation function from multiple separate mechanical contact points and consolidates it into contacts between detent geometries on housing portions and counter-detent geometries on the limiter disk. This reduction in the number of mechanical contacts decreases noise and mechanical stress.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If a single limiter disk is used with axial displacement, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvenumber of limiter disksVSAvoidthread guidance and detent geometry alignment

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The sliding guide acts as an intermediary element between the limiter disk and the housing, providing precise axial displacement guidance. This intermediary component ensures that the limiter disk moves accurately along the central axis during rotation, maintaining the required manufacturing precision while simplifying the overall device structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If detent geometries are positioned at axial extremes, then rotation limitation range is maximized, but housing volume increases

Engineering Contradiction:

Improverotation limitation rangeVSAvoidhousing volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent utilizes the axial dimension efficiently by positioning detent geometries at opposite axial ends of the housing. This arrangement maximizes the rotation limitation range (540 degrees or 1.5 revolutions) within a compact housing volume by leveraging the axial displacement of the single limiter disk rather than requiring extended radial or circumferential dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 module effectively limits steering wheel rotation in both directions while being compact, quiet, and easy to adjust, ensuring reliable operation and extended service life with reduced noise and mechanical stress.

Implementation Method 1

The rotation limitation module has a limiter disk which by way of a sliding guide is coupled in a rotationally fixed manner to the shaft portion and has an external thread which is driven into an internal thread of the housing

Methodology Applied

Scientific EffectThread mechanism: Screw

Data Source

PatentUS11772701B2Rotation limitation module and steering wheel module for a steer-by-wire steering system

Publication Date: 2023.10.03 ZF AUTOMOTIVE GERMANY GMBH

AI summary

Described is a rotation limitation module for a steer-by-wire steering system. Said rotation limitation module comprises a housing in which a shaft portion is received. Furthermore, a limiter disk by way of a sliding guide is coupled in a rotationally fixed manner to the shaft portion and by way of an external thread is driven into an internal thread of the housing. Provided on the housing are detent geometries and on the limiter disk counter-detent geometries which, for limiting a rotation of the shaft portion in a first rotation direction and a second rotation direction, counter to said first rotation direction, are configured for contacting a respectively assigned detent geometry. A steering wheel module for a steer-by-wire steering system, which comprises such a rotation limitation module, is also disclosed.