Steering Torque Device Eliminates Transmission Noise
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Solution Overview
Problem
Existing mechanical restoring torque generating devices for steer-by-wire steering systems face challenges in providing a comfortable and cost-effective operation, as they require a transmission to achieve the necessary restoring torque, which can lead to noise, vibration issues, and the need for high spring constants, limiting their angular range and efficiency.
Innovation Solution
A mechanical restoring torque generating device comprising a first and second spring unit, a driver that decouples and recouples with the spring units during different rotation directions, eliminating the need for a transmission, allowing for rotation angles greater than 360° without additional components, and incorporating further spring elements to counteract restoring torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a transmission is integrated in the steering wheel region to transmit rotation from the steering shaft to the spiral springs, then the restoring torque can be generated, but noise and vibrations increase requiring additional damping measures
Solution Approach 1:
The patent removes the transmission component from the system entirely. Instead of using a transmission to connect the steering shaft to the spiral springs, the design allows the steering shaft to directly actuate the driver, which in turn loads or unloads the spiral springs. This extraction of the transmission element eliminates the source of noise and vibrations while preserving the restoring torque generation function.
2Force
If a transmission is used to transmit rotation from the steering shaft to the spiral springs, then the restoring torque can be generated, but the device complexity increases
Solution Approach 1:
The transmission is completely removed from the system. The steering shaft directly drives the driver through a simplified connection, eliminating the need for complex transmission mechanisms while maintaining the ability to generate restoring torque through the spiral springs.
Solution Approach 2:
The driver is segmented into two functional parts: a first portion that interacts with the first spiral spring and a second portion that interacts with the second spiral spring. This segmentation allows each spring to be independently loaded or unloaded based on the rotation direction, simplifying the overall mechanism by eliminating the need for a transmission to manage bidirectional torque generation.
3Force
If the spiral springs are dimensioned with high spring constant to generate high restoring torques, then the restoring torque is sufficient, but the angle of rotation required at the steering handle increases
Solution Approach 1:
The system dynamically switches between two spiral springs based on the direction of rotation. The driver can be rotated by angles greater than 360° in each direction, allowing the first spiral spring to be loaded during rotation in one direction and the second spiral spring during rotation in the opposite direction. This dynamic configuration allows for more efficient torque generation with reduced rotation angles.
4Speed
If the driver is decoupled from one spring unit during rotation in one direction, then the rotation angle can exceed 360°, but the mechanism complexity increases
Solution Approach 1:
The driver is divided into a first portion and a second portion, where the first portion interacts with the first spiral spring and the second portion interacts with the second spiral spring. This segmentation naturally enables the decoupling function - when the driver rotates in one direction, one portion remains engaged while the other becomes disengaged, allowing rotation angles greater than 360° without requiring additional complex decoupling mechanisms.
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
This design enhances operational comfort and reduces manufacturing costs by eliminating the need for a transmission, allowing for efficient torque generation over a wider range of motion while minimizing noise and vibration, and providing a reliable fallback mechanism in case of electronic actuator failure.
Implementation Method 1
a first spring unit for generating a first restoring torque
Implementation Method 2
a second spring unit for generating a second restoring torque
Data Source
AI summary
A restoring torque generating device for generating a restoring torque acting on a steering handle of a vehicle comprising a first spring unit for generating a first restoring torque, a second spring unit for generating a second restoring torque, a driver cooperating with the first and the second spring unit. The driver can be coupled with a steering shaft of the vehicle such that during a rotation of the steering shaft in a first direction of rotation it acts on the first spring unit and during a rotation of the steering shaft in an opposite, second direction of rotation it acts on the second spring unit.