Vehicle Toe Angle Actuator Gear Backlash Noise Suppression
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Solution Overview
Problem
The existing rear wheel toe angle control systems for vehicles produce a rattling sound due to gear backlash in the actuator's gear transmission mechanism, which is difficult to mitigate without increasing manufacturing costs.
Innovation Solution
A toe angle control system that includes an actuator with a gear transmission mechanism and a controller that adjusts the operation quantity of the electric motor to reduce the displacement speed of the output part before gear collisions occur, thereby minimizing the kinetic energy and the resulting rattling sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the backlash in the gear transmission mechanism is reduced to lower the rattling sound, then the manufacturing precision of the gears must be increased, but this results in higher manufacturing cost
Solution Approach 1:
The controller performs preliminary action by detecting the displacement direction of the output part before gear collision occurs and correcting the operation quantity in advance. This prevents the electric motor from driving the gears into collision at high speed, thereby reducing rattling sound without requiring higher manufacturing precision of the gears
Solution Approach 2:
The controller changes the operation quantity parameter dynamically based on the detected displacement direction. When opposite displacement directions are detected, the operation quantity is corrected to reduce the motor speed, thereby controlling the kinetic energy and reducing gear collision noise without affecting manufacturing precision
2Object-affected harmful factors
If the operation quantity of the electric motor is not corrected, then the response speed is maintained, but the relative speed between gear teeth at collision increases causing more rattling sound
Solution Approach 1:
The controller uses feedback from the sensor detecting the output part displacement direction to determine when gear collision is imminent. Based on this feedback, the controller corrects the operation quantity to reduce motor speed before collision occurs, thereby suppressing rattling sound while maintaining adequate response speed through selective correction only when necessary
Data Source
AI summary
A toe angle control system for a vehicle, includes: an actuator having an output part configured to receive a driving force of an electric motor via a gear transmission mechanism and to be displaced by the driving force such that a displacement of the output part varies a toe angle of a wheel; and a controller controlling the electric motor, wherein the controller is configured to calculate an operation quantity of the electric motor, and, when the controller determines that a current displacement direction of the output part and a displacement direction of the output part corresponding to the operation quantity are opposite to each other, the controller corrects the operation quantity to reduce the operation quantity.