Steer-by-Wire Steering Locking for Wheel-End Rotation Limits
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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 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 operated by a cam member driven by a driving motor to prevent excessive rotation when the steering torque exceeds the reaction torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a steer-by-wire type steering apparatus is used to remove mechanical connection between steering shaft and wheel, then the steering operation convenience is improved, but the steering sense is degraded due to unlimited rotation of steering wheel
Solution Approach 1:
A reaction motor is introduced as an intermediary between the steering shaft and the wheel to provide tactile feedback to the driver. The reaction motor generates reaction torque that simulates the mechanical connection sensation, allowing the driver to feel resistance and feedback without direct mechanical linkage, thus resolving the contradiction between operational convenience and steering sense reliability
Solution Approach 2:
The traditional mechanical connection between steering shaft and wheel is replaced with an electrically-powered system using a reaction motor. This substitution eliminates the need for physical mechanical linkage while maintaining the functional equivalence of providing steering feedback through electromagnetic torque generation
2Adaptability or versatility
If the steering wheel can rotate unlimitedly in steer-by-wire system, then the steering operation flexibility is improved, but the safety is worsened when wheels reach maximum point or collide with curbstone
Solution Approach 1:
The rotation preventing member is pre-configured in the system to automatically engage when the steering shaft attempts to rotate beyond the safe range. This preliminary arrangement ensures that before excessive rotation can cause harm, the mechanical constraint is already in place to prevent it, thus maintaining safety while preserving operational flexibility within normal ranges
Solution Approach 2:
A rotation preventing member with engaging protrusions and grooves is implemented to provide preliminary counter-action against excessive steering shaft rotation. When the steering shaft reaches the maximum rotation point, the engaging protrusions on the rotation preventing member engage with the grooves on the shaft, creating a mechanical barrier that prevents further rotation and potential damage before it can occur
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 apparatus effectively prevents the steering shaft from rotating when a larger steering torque than the reaction torque is applied, providing the necessary mechanical limitation to the driver and enhancing the steering experience by indicating when the wheels have reached a maximum point or collided with a curbstone.
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
the first pulley and the second pulley are embedded, via a hinge shaft to rotate
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.