Steer-by-Wire Steering Shaft Locking at Wheel End Stops
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Solution Overview
Problem
In steer-by-wire type steering apparatuses, the lack of mechanical connection between the steering shaft and wheel results in unlimited rotation of the driver's steering wheel, degrading the driver's steering sense, and there is a need to prevent further rotation when the wheels reach a maximum point or collide with a curbstone.
Innovation Solution
A steer-by-wire type steering apparatus is designed with a first pulley coupled to the steering shaft, a second pulley connected via a belt to a reaction motor, an engaging member with grooves, and rotation-preventing members that are supported in these grooves and rotated by a cam member, which prevents the steering shaft from rotating when the driver applies a steering torque greater than the reaction torque of the reaction motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a steer-by-wire type steering apparatus is used to remove mechanical connection components, then the steering system becomes more simplified and controllable, but the driver's steering sense is degraded due to unlimited rotation of the steering wheel
Solution Approach 1:
A reaction motor is introduced as an intermediary between the steering wheel and the road. The reaction motor generates reaction torque to simulate the mechanical feedback that would normally be provided by the mechanical connection, allowing the driver to feel road conditions and wheel position without direct mechanical linkage.
Solution Approach 2:
The system implements feedback by using sensors to detect steering wheel position and road conditions, then the reaction motor generates appropriate reaction torque to provide the driver with tactile feedback about the steering state and road surface conditions, recreating the sensation of mechanical connection.
2Adaptability or versatility
If the steering wheel is allowed to rotate freely without mechanical connection, then the steering apparatus achieves full steering range, but the steering shaft continues to rotate beyond the maximum wheel position degrading steering precision
Solution Approach 1:
The rotation preventing mechanism is activated in advance when the steering wheel reaches a predetermined rotation angle. The reaction motor generates reaction torque to prevent the steering shaft from rotating beyond the maximum wheel position, stopping the shaft rotation before excessive rotation degrades steering precision.
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
This solution effectively prevents the rotation of the steering shaft when a larger steering torque is applied than the reaction torque, providing the necessary mechanical limitation and feedback to the driver, enhancing the steering experience by preventing excessive rotation.
Implementation Method 1
a second pulley connected to the first pulley via a belt
Implementation Method 2
a cam member disposed between one ends of the pair of rotation-preventing members, being rotated while being coupled to a shaft of a driving motor and rotating each of the rotation-preventing members around the hinge shaft
Implementation Method 3
when a driver generates a larger steering torque than a reaction torque of a reaction motor in the steering shaft
Data Source
AI summary
The present disclosure relates to a steer-by-wire type steering apparatus. According to present embodiments, in the steer-by-wire type steering apparatus, when a driver generates a larger steering torque than a reaction torque of a reaction motor in a steering shaft, rotation of the steering shaft can be prevented.