Non-Backdrivable Clutch Module for Active Aerodynamics Actuators
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Solution Overview
Problem
Existing bi-directional actuators face challenges in preventing backdriving forces from reaching the input drive, protecting the system from damage, and efficiently decoupling the output shaft during large torque inputs while transferring vibration and impact loads to the device structure without electrical position sensors.
Innovation Solution
A non-backdrivable clutched module with a housing containing an input shaft cog and a clutched output shaft, featuring a clutch cog with both resilient and detent connections, which engages and disengages to prevent backdriving forces and decouples during excessive loads, using a spring and bearing system to manage torque transfer and lock the output shaft in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-backdrivable clutch mechanism is implemented to prevent backdriving forces from reaching the input drive, then the actuator is protected from damage, but the device complexity increases due to the need for clutch cogs, resilient connections, and detent connections
Solution Approach 1:
The clutch cog acts as an intermediary element between the input shaft cog and the output shaft, selectively engaging or disengaging to prevent backdriving forces from reaching the actuator while allowing normal torque transmission in the forward direction
Solution Approach 2:
The clutch mechanism dynamically transitions between engaged and disengaged states based on the direction and magnitude of applied forces, automatically protecting the actuator during backdriving conditions while maintaining normal operation during forward driving
2Stability of the object's composition
If the clutch cog has both resilient connection and detent connection to the clutch cog receiving portion, then the output shaft can be effectively locked during normal operation, but the device complexity increases due to the dual connection system
Solution Approach 1:
The resilient connection and detent connection are merged into a unified clutch cog assembly, where both connection types work together to provide stable locking during normal operation while allowing automatic disengagement under excessive load conditions
Solution Approach 2:
The resilient connection provides beforehand cushioning by allowing elastic deformation to absorb shock loads and prevent immediate failure, while the detent connection provides positive locking for stable operation under normal conditions
3Reliability
If the clutch cog disengages from the clutch cog receiving portion during excessive backdriving forces, then the output shaft is protected from damage, but the loss of torque transmission capability occurs during the disengaged state
Solution Approach 1:
The harmful backdriving force that causes excessive load is converted into a beneficial protective mechanism, where the force itself triggers the disengagement of the clutch cog to prevent damage to the output shaft and actuator
Solution Approach 2:
The clutch mechanism is self-regulating, automatically disengaging when excessive backdriving forces are detected and automatically re-engaging when normal operating conditions are restored, without requiring external control systems
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 prevents backdriving forces from reaching the input drive, protects the actuator from damage, and decouples the output shaft during high loads, ensuring safe torque transfer and vibration management without the need for electrical position sensors.
Implementation Method 1
The clutch cog has both a resilient connection and a detent connection to the clutch cog receiving portion of the clutched output shaft
Implementation Method 2
The clutch cog acts on at least one bearing member between the clutch cog and the housing
Data Source
Figure 1
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AI summary
A non-backdrivable clutched module for a bi-directional actuator such as actuators used for active aerodynamics on vehicles. The module has both a stopper mode and a clutch mode. During the stopper mode a back- driving force gets diverted away from the actuator using a locking bearing member. If the force is too great a clutch mode will disengage the back- driving force completely from the shaft connected to the actuator, thereby preventing damage to the actuator.