Ball-and-Ramp Torque Limiter With Rotation-Difference Trip
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Solution Overview
Problem
Existing torque limiter devices in aerospace applications fail to effectively protect upstream components from excessive torque caused by jams or blockages downstream of the clutch, leading to potential damage due to rapid deceleration and over-torque issues.
Innovation Solution
A torque limiter device with an input and output shaft, a biasing mechanism, an electromagnet, and a rotation sensor system that detects differences in rotation speed and automatically disengages the shafts when excessive torque is detected, using a combination of contact friction and ball-and-ramp mechanisms to control torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the contact surfaces of the shafts are brought into mechanical engagement for power transmission, then the power transmission efficiency is improved, but the risk of excessive torque and component damage increases when downstream blockage occurs
Solution Approach 1:
The clutch mechanism transitions from a static engaged/disengaged state to a dynamic slip state when excessive torque is detected. The friction contact surfaces are designed to slip relative to each other when the torque exceeds a predetermined threshold, allowing the system to dynamically adjust and protect itself from damage while maintaining power transmission capability during normal operation.
Solution Approach 2:
A friction interface is introduced as an intermediary between the input and output shafts. This friction contact surface acts as a torque-limiting mediator that can slip when excessive torque occurs, preventing direct transmission of damaging forces to upstream components while still allowing efficient power transmission during normal operation.
2Reliability
If the shafts are rapidly disengaged to protect from excessive torque, then component protection is improved, but the response time and control precision deteriorate without a sensor system
Solution Approach 1:
Rotation sensors are installed on both the input and output shafts to continuously monitor their rotational speeds. The control system receives feedback from these sensors and automatically activates the electromagnet when it detects a speed difference indicating excessive torque or downstream blockage, enabling rapid protective disengagement.
Solution Approach 2:
The manual or mechanical clutch control system is replaced with an electromechanical control system using an electromagnet and electronic sensors. This substitution enables faster and more precise detection and response to excessive torque conditions compared to purely mechanical systems.
3Ease of operation
If friction clutch is used for torque transmission, then the ease of operation is improved, but the torque control precision deteriorates due to slippage
Solution Approach 1:
The friction clutch interface is designed to automatically regulate torque transmission based on operating conditions. When excessive torque occurs, the friction surfaces naturally slip and limit the transmitted torque without requiring external intervention, allowing the system to self-protect while maintaining ease of operation.
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
The device prevents damage to upstream components by rapidly disengaging the output shaft from the input shaft when excessive torque is detected, ensuring immediate cessation of power transmission and protecting mechanical components from over-torque conditions.
Implementation Method 1
an electromagnet arranged to provide an electromagnetic force that opposes said bias force when an activation current is passed through a coil of said electromagnet
Implementation Method 2
a biasing mechanism arranged to provide a bias force that biases the input and output shafts in one of the positions
Implementation Method 3
a friction clutch operates by bringing opposing faces of the two shafts into physical contact, either directly or via an intervening friction plate. Due to the frictional contact between the faces when in contact with one another, rotation of one shaft imparts rotation of the other shaft
Data Source
AI summary
A torque limiter device includes an input shaft having a first contact surface and an output shaft having a second contact surface. The input and output shafts are operable in an engaged position and a disengaged position A biasing mechanism provides a bias force that mechanically biases the input and output shafts in one of the positions and sets a threshold torque. An electromagnet is arranged to selectively provide an electromagnetic force that opposes the bias force when an activation current is supplied. A controller determines a difference in rotations of the shafts and selectively supply the activation current to the electromagnet so as to disengage the input and output shafts when the rotation difference exceeds a threshold. Each of the contact surfaces comprises one or more grooves, wherein at least one rotatable member is disposed in at least one of said grooves.