Steering Wheel Hub End Stop Using Spiral Groove Limiting
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Solution Overview
Problem
Prior art steer-by-wire systems have a complex structure and are limited in functionality and adaptability to different vehicle requirements, particularly in providing a robust and reliable solution for limiting the maximum angle of rotation.
Innovation Solution
A steer-by-wire steering system that includes a steering wheel hub connected to a steering wheel, a torque feedback device with an electric machine, and a steering wheel rotation limiting device. The rotation limiting device features a base with end stop surfaces and a sliding element that engages a spiral groove on the steering wheel hub, allowing for mechanical limitation of rotation in both directions while allowing more than 360° rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical end stop device is added to limit steering wheel rotation, then reliability is improved, but device complexity increases
Solution Approach 1:
The rotation limiting device is nested within the existing steering wheel assembly structure. The sliding element is received within a receiving space formed by the steering wheel hub and the rotation limiting device itself, creating a compact integrated design that adds rotation limiting functionality without significantly increasing overall device complexity
Solution Approach 2:
The sliding element acts as an intermediary mechanical component between the steering wheel hub and the rotation limiting device. It translates rotational movement into axial movement and provides the mechanical end stop function through contact with end stop surfaces, enabling reliable rotation limitation while maintaining a simple structural design
2Reliability
If the electric machine provides full stopping torque to limit rotation, then reliability is improved, but energy consumption increases
Solution Approach 1:
The patent replaces the electrical control mechanism (electric machine providing stopping torque) with a passive mechanical end stop system. The sliding element and end stop surfaces provide mechanical rotation limitation without requiring continuous electrical power, significantly reducing energy consumption while maintaining reliable rotation limits
Solution Approach 2:
The electric machine only needs to operate periodically to return the sliding element to its initial position after rotation limiting has occurred, rather than continuously providing stopping torque. This periodic operation dramatically reduces overall energy consumption while maintaining the reliability of rotation limitation
3Adaptability or versatility
If a complex rotation limiting structure is used, then adaptability to different vehicle requirements is improved, but ease of manufacture worsens
Solution Approach 1:
The rotation limiting device is designed as a universal component that can be integrated into different steering wheel assemblies for various vehicle types. The modular design with standardized elements (sliding element, receiving space, end stop surfaces) allows adaptation to different vehicle requirements while maintaining manufacturing simplicity through component standardization
Solution Approach 2:
The rotation limiting device is segmented into distinct functional components: the sliding element, the receiving space, and the end stop surfaces. This segmentation allows each component to be manufactured independently using simple processes and then assembled, improving ease of manufacture while maintaining adaptability through configurable component arrangements
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 robust and reliable mechanical end stop function in a steer-by-wire system, avoiding the need for full stopping torque from the electric machine, and allowing for flexible integration and adaptation to different vehicle configurations.
Implementation Method 1
a sliding element (56) that is axially slidable parallel to the axis of rotation relative to the base and relative to the steering wheel hub between the two opposing end stop surfaces. The sliding element (56) comprises a projection (64) that engages a spiral groove (66) formed on a circumferential surface of the steering wheel hub
Implementation Method 2
abutment of the sliding element (56) with one of the two end stop surfaces blocks movement of the sliding element (56) and rotation of the steering wheel hub
Data Source
AI summary
A steering system includes a steering wheel rotation limiting device being arranged radially offset to the steering wheel hub and including a base being fixed to the or another non-rotatable component of the steering system and a sliding element. The base includes two opposing end stop surfaces, and the sliding element is axially slidable parallel to the axis of rotation relative to the base and relative to the steering wheel hub between the two opposing end stop surfaces. The sliding element includes a projection that engages a spiral groove formed on a circumferential surface of the steering wheel hub so that rotation of the steering wheel hub causes axial movement of the sliding element, and so that abutment of the sliding element with one of the two end stop surfaces blocks movement of the sliding element and rotation of the steering wheel hub.