Steer-by-Wire Clutch Actuator for Rotation Limiting
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Solution Overview
Problem
Conventional vehicle steering systems require mechanical linkages, which are not necessary in steer-by-wire systems, necessitating the use of end stops to prevent continuous rotation of the steering wheel, but existing solutions lack effective mechanisms to inhibit rotation at predetermined limits.
Innovation Solution
A steer-by-wire assembly incorporating a shaft, a clutch with a brake member and a reaction member, and an electromagnetic actuator that selectively engages or disengages the brake and reaction members to limit or permit rotation, using biasing members to provide frictional engagement when the actuator is de-energized and allowing rotation when energized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical linkages are used in steering systems, then the steering wheel rotation is naturally limited by the mechanical connection, but the system complexity increases and is not suitable for steer-by-wire architectures
Solution Approach 1:
The patent replaces the traditional mechanical linkage system with an electromagnetic actuator that uses magnetic fields to control the brake member's engagement with the reaction member. This substitution eliminates complex mechanical linkages while maintaining the ability to limit steering wheel rotation through electromagnetic force rather than mechanical connection.
Solution Approach 2:
The patent introduces a brake member as an intermediary component between the steering wheel and the reaction member. This brake member serves as a mediator that can be selectively engaged or disengaged through electromagnetic actuation, providing rotation limitation without requiring direct mechanical linkage between the steering components.
2Reliability
If end stops are added to prevent continuous rotation in steer-by-wire systems, then rotation limitation is achieved, but the device complexity increases
Solution Approach 1:
The brake member serves multiple functions: it acts as an end stop to prevent continuous rotation, provides a mechanical backup for safety, and can be selectively engaged or disengaged through electromagnetic actuation. This multi-functionality achieves rotation limitation without requiring separate dedicated end stop mechanisms, thereby reducing overall device complexity.
Solution Approach 2:
The electromagnetic actuator automatically engages or disengages the brake member based on system requirements, eliminating the need for separate control mechanisms. The system self-regulates the brake member's engagement state through electromagnetic force, providing reliable rotation limitation without adding complex control circuitry or additional components.
3Ease of operation
If a brake member with frictional engagement is used to limit rotation, then rotation control is effective, but energy loss increases due to friction
Solution Approach 1:
The brake member's engagement state is dynamically controlled through electromagnetic actuation. The system transitions between engaged and disengaged states based on operational requirements, allowing frictional energy loss to occur only when rotation limitation is needed rather than continuously. This dynamic control optimizes energy efficiency by minimizing frictional losses during normal steering operations.
Solution Approach 2:
The electromagnetic actuator periodically engages or disengages the brake member based on steering wheel position and system requirements. This periodic engagement provides rotation control only when necessary (at predetermined limits), reducing continuous frictional energy loss while maintaining effective rotation control when needed.
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
Effectively inhibits steering wheel rotation at predetermined limits and provides a mechanical backup in case of power loss, ensuring safe and controlled steering.
Implementation Method 1
an electromagnetic actuator that is selectively actuated to selectively provide a force to selectively engage the brake and reaction members
Implementation Method 2
the force between the brake and reaction members limits or prevents rotation of the brake member relative to the reaction member
Data Source
AI summary
A steer-by-wire assembly for a steering system in a vehicle is described. The system includes a shaft (44) rotatable in response to a steering input, a clutch (79) that includes a brake member (80) rotatable with the shaft (44) and a reaction member (112), and an electromagnetic actuator (76) that is selectively actuated to selectively provide a force to selectively engage the brake and reaction members (80, 112). When the actuator (76) is not actuated, the force between the brake and reaction members (80, 112) limits or prevents rotation of the brake member (80) relative to the reaction member (112). And when the actuator (76) is actuated, the force between the brake and reaction members (80, 112) is reduced or removed to permit rotation of the brake member (80) relative to the reaction member (112).