Steer by Wire Coupling Unit for Motor Load Reduction
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Solution Overview
Problem
Conventional steer by wire apparatuses face challenges in optimizing motor capacity and size while maintaining geometry characteristics, as they require complex mechanisms and increased load due to the conversion of vertical motor rotations into horizontal steering angles.
Innovation Solution
A steer by wire apparatus that incorporates a coupling unit with a first and second rotation shaft, along with couplers, to convert vertical motor rotations into horizontal rotations, allowing the tie rod to slide and control steering angles, thereby optimizing motor capacity and size without altering geometry characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional steer by wire mechanism uses L-shape levers and tie rod movement, then steering operation is achieved, but motor capacity and size increase due to increased load and usage of current
Solution Approach 1:
The patent introduces a coupling unit with two rotation shafts positioned at different dimensions (first rotation shaft in vertical direction, second rotation shaft in horizontal direction) to convert the rotation direction from vertical to horizontal. This dimensional transformation allows the motor to operate in its optimal vertical rotation direction while achieving horizontal tie rod movement, thereby reducing motor load and optimizing motor capacity without increasing device complexity.
2Ease of operation
If the tie rod inner point moves forward or rearward as well as to the left or to the right, then steering operation is achieved, but geometry characteristic of the tie rod changes
Solution Approach 1:
The patent segments the steering motion into two independent rotational movements: first rotation of the first rotation shaft (vertical direction) and second rotation of the second rotation shaft (horizontal direction). The coupler connects these two rotations, allowing the tie rod to move horizontally without forward or rearward movement. This segmentation maintains the tie rod's geometry characteristic while achieving effective steering control.
3Productivity
If L-shape levers and tie rod are operated only by the actuator, then steering operation is achieved, but performance on demand of the actuator and cost increase
Solution Approach 1:
The patent replaces the conventional actuator-only mechanical system with a hybrid system that utilizes both the actuator and the driver's steering wheel input. The coupling unit translates the driver's rotational input on the steering wheel into appropriate tie rod movement, reducing the burden on the actuator and lowering overall system cost while maintaining or improving steering response performance.
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 solution enables efficient steering angle control, reduces costs, and minimizes excessive load on the motor by converting vertical rotations into horizontal movements, maintaining optimal motor capacity and size while preventing geometry changes.
Implementation Method 1
converting rotation direction of torque from a first rotation direction to a second rotation direction which is substantially perpendicular to the first rotation direction
Data Source
AI summary
A steer by wire apparatus performing steering operation by turning a wheel when a vehicle turns, may include a tie rod provided with one end pivotally connected to a knuckle of the wheel, a coupling unit rotatably mounted at a sub-frame of a vehicle body, connected to the other end of the tie rod, and converting rotation direction of torque from a first rotation direction to a second rotation direction which is substantially perpendicular to the first rotation direction so as to slidably move the tie rod from the coupling unit and control a steering angle of the wheel, and a motor unit fixed to the sub-frame and supplying the torque to the coupling unit according to a control signal of a vehicle ECU, the rotation direction of the torque being the same as the first rotation direction or being opposite to the first rotation direction.