Hand Wheel Actuator Belt Drive Layout for Compact Steer-by-Wire
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Solution Overview
Problem
Steer-by-wire systems face challenges in constrained space under the dashboard and higher material costs due to the need for a second actuator, making it advantageous to eliminate the torque sensor while maintaining excellent steering feel.
Innovation Solution
A hand wheel actuator assembly with an integrated belt drive and controller, featuring a motor shaft, hand wheel shaft, and a belt drive assembly with adjustable idler pulleys, which allows for efficient space utilization and reduced material costs by positioning the circuit board between the belt and motor, simplifying sensor design and motor phase connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second actuator (RWA) is added to provide torque feedback in steer-by-wire systems, then steering feel is improved, but device complexity and material cost increase
Solution Approach 1:
The patent extracts and eliminates the torque sensor from the conventional steer-by-wire system by repositioning the hand wheel actuator assembly to directly sense hand wheel position without requiring separate torque sensing components. The HWA assembly is integrated into the steering column such that the motor shaft couples to the hand wheel shaft, allowing direct position feedback to the RWA without torque sensor intervention.
Solution Approach 2:
The hand wheel actuator assembly performs multiple functions: it provides hand wheel position sensing, generates torque feedback to the hand wheel, and couples the motor shaft to the hand wheel shaft. This multi-functional integration eliminates the need for separate torque sensors and reduces system complexity while maintaining steering feel through the collaborative HWA-RWA system.
2Extent of automation
If conventional steering systems are replaced with steer-by-wire systems, then automation and control are improved, but material cost increases due to additional actuators
Solution Approach 1:
The patent merges the hand wheel actuator assembly with the steering column integration, combining the motor, motor shaft, hand wheel shaft, and position sensing functions into a single integrated assembly. This merging eliminates the need for separate torque sensors and reduces the overall component count, thereby reducing material costs while maintaining the automated steer-by-wire control functionality.
3Area of stationary object
If space under the dashboard is constrained, then packaging requirements become more stringent, but integration of additional components becomes difficult
Solution Approach 1:
The patent implements a nested arrangement where the motor shaft is coupled to the hand wheel shaft through the belt drive assembly within the integrated HWA assembly. The circuit board is positioned between the motor and belt, and the idler pulley is integrated into the same housing. This nesting of components within the steering column assembly maximizes space utilization under the dashboard while reducing packaging complexity.
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 enables efficient space utilization and cost reduction in steer-by-wire systems by integrating the belt drive and controller, allowing for effective hand wheel position feedback and torque management without the need for a torque sensor, thereby improving steering feel and reducing material costs.
Implementation Method 1
a belt in contact with the drive pulley and the driven pulley to rotatably couple the motor shaft and the hand wheel shaft
Implementation Method 2
a pair of idler pulleys which may be adjusted by an adjustment device to adjust the tension between the motor shaft and the hand wheel shaft
Data Source
AI summary
A hand wheel actuator assembly, the hand wheel actuator assembly includes a motor. The hand wheel actuator assembly also includes a motor shaft coaxially aligned with a motor axis, the motor shaft rotatably coupled to the motor, and the motor configured to cause rotation of the motor shaft about the motor axis. The hand wheel actuator assembly further includes a hand wheel shaft coaxially aligned with a hand wheel axis, the hand wheel shaft spaced from and parallel to the motor shaft, wherein the motor shaft is coupled to the hand wheel shaft by a belt. The hand wheel actuator assembly yet further includes a circuit board located between the belt and the motor.