Steer-by-Wire System with Switchable Clutch for Parking Torque
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Solution Overview
Problem
Steer-by-wire systems with individual wheel steering face challenges in achieving precise wheel tracking and high pivoting forces, particularly during parking, due to the need for powerful actuators that occupy significant space and increase costs.
Innovation Solution
A steer-by-wire steering system with two electronically controlled actuators that connect via a switchable clutch, allowing for shared drive power during high tie rod force conditions, enabling smaller actuators to be used while maintaining required pivoting forces, and disconnecting after the condition is met, thus reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If individual wheel steering systems are used with powerful actuators to withstand maximum tie rod forces during parking, then the required pivoting forces are achieved, but the actuators occupy significant space and increase costs
Solution Approach 1:
The patent merges two actuators into a coupled system where they can work together during parking maneuvers. The coupling device allows the actuators to be connected in parallel, combining their output forces to withstand maximum tie rod forces during parking while maintaining individual operation during normal driving, thus reducing the size requirement for each individual actuator
2Force
If individual wheel steering systems are used with powerful actuators to withstand maximum tie rod forces during parking, then the required pivoting forces are achieved, but the system costs increase
Solution Approach 1:
By combining two smaller actuators into a coupled system, the patent reduces the cost compared to using a single large actuator. The coupling device enables cost-effective individual wheel steering by allowing standard-sized actuators to work together during parking maneuvers, achieving the required force output without the high cost of oversized individual actuators
3Volume of moving object
If a switchable clutch is added to couple actuators during parking, then actuator size is reduced, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic coupling system where the clutch can switch between engaged and disengaged states based on driving conditions. During parking maneuvers, the clutch engages to couple the actuators; during normal driving, it disengages to allow independent actuator operation. This dynamic approach reduces average actuator size while managing system complexity through conditional operation
Data Source
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AI summary
The invention relates to a steer-by-wire steering system for motor vehicles having at least two steering regulators which act on the steered wheels (201, 251) and are regulated electronically in a manner which is dependent on a driver's steering request, having a feedback actuator (4) which transmits feedback moments to a steering wheel, and a control unit (6) which actuates the feedback actuator (4) and the at least two steering regulators in order to generate drive power, wherein the at least two steering regulators have in each case one actuator with an output shaft, wherein, in a normal case, each steerable vehicle wheel (201, 251) is assigned a single steering regulator with an actuator in the form of a single-wheel steering system (20, 25), and a rotation of the respective steerable vehicle wheel (201, 205) about a pivoting axis (267) is brought about by way of a rotation of the output shaft of the actuator (202, 252), wherein a switchable clutch (14, 100) is provided which is configured in such a way that it is open in the normal case and is closed in the special case of parking, wherein the clutch (14, 100) connects the single-wheel steering systems (20, 25) to one another in the closed state in such a way that drive power can be transmitted from one single-wheel steering system (20, 25) to the other single-wheel steering system (20, 25) in order to rotate a steerable vehicle wheel (201, 251).