Steer-by-Wire Travel Stop Assembly for Handwheel Over-Rotation
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Solution Overview
Problem
In steer-by-wire vehicle steering systems, there is no mechanical linkage to limit the rotation of the handwheel, leading to potential damage to components due to over-rotation.
Innovation Solution
A travel stop assembly with a shaft and a nut that includes a spiral track and a housing, where the nut is rotationally fixed to limit the axial movement and rotational angle of the shaft, using contact points to define predetermined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct mechanical linkage is used between handwheel and tires, then rotation of handwheel is limited, but components like clock spring and air bag coil are protected from damage
Solution Approach 1:
The patent replaces the traditional direct mechanical linkage with a steer-by-wire electrical control system. The handwheel actuator receives electrical signals from the steering wheel and controls the roadwheel actuator accordingly, eliminating the need for continuous mechanical connection while maintaining steering control functionality
Solution Approach 2:
The patent introduces an intermediary control system consisting of sensors, wires, and a central processing unit that mediates between the steering wheel and roadwheel actuator. This intermediary layer enables independent control of handwheel rotation without mechanical constraints while protecting components through controlled movement limits
2Ease of operation
If no mechanical linkage is used between handwheel and tires, then handwheel can rotate freely, but components are subject to damage due to over-rotation
Solution Approach 1:
The patent incorporates sensors that detect handwheel rotation position and send feedback signals to the central processing unit. The control system uses this feedback to monitor rotation angles and prevent over-rotation by stopping the handwheel actuator when predetermined limits are reached, thus protecting components while maintaining operational freedom
Solution Approach 2:
The patent applies preliminary anti-action by implementing predetermined rotation limits and stop conditions in the control system before damage can occur. The system proactively prevents over-rotation through software-controlled movement boundaries rather than relying on mechanical stoppers, thereby protecting components while allowing free rotation within safe limits
Data Source
AI summary
A travel stop assembly for a vehicle steer-by-wire steering system includes a shaft defining a spiral track extending from a first track end to a second track end. The travel stop assembly also includes a nut extending radially from an inner radial surface to an outer radial surface, the nut extending circumferentially from a first circumferential end to a second circumferential end, wherein the inner radial surface is disposed within the spiral track, wherein the nut is rotationally fixed such that rotation of the shaft axially translates the nut along the spiral track, wherein the first track end, the second track end, the first circumferential end and the second circumferential end are positioned to limit the axial movement of the nut and rotation of the shaft to a predetermined axial distance of the nut and a predetermined rotational angle of the shaft.