Rotary Actuator Stop Module With Deformable Disk End Stop
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Solution Overview
Problem
Conventional end-of-stroke stopping mechanisms for actuators are heavy, large, and inefficient in dissipating excess rotational kinetic energy, making them unsuitable for applications like aircraft control surfaces where quick and safe stopping is critical.
Innovation Solution
An actuator with a travel-limiting stop module that employs a timing gear system to articulate a stopping pawl and a low-inertia, deformable stopping disk to dissipate excess rotational kinetic energy without relying on friction, allowing for a lighter and smaller design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional friction-based brake plates or torsionally compliant shaft systems are used to dissipate excess rotational kinetic energy, then the stopping function is achieved, but the actuator becomes heavy and large in size
Solution Approach 1:
The patent replaces the conventional friction-based mechanical braking system with a deformable element that dissipates energy through controlled deformation. Instead of using friction plates or compliant shafts, the invention employs a deformable element that absorbs excess rotational kinetic energy through elastic or plastic deformation, eliminating the need for heavy friction-based stopping mechanisms
Solution Approach 2:
The patent changes the physical state and properties of the stopping mechanism by using a deformable element with specific material properties. The deformable element is designed to undergo controlled deformation at predetermined locations, transforming the stopping mechanism from a rigid friction-based system to a compliant energy-absorbing structure with optimized weight and size
2Reliability
If conventional friction-based brake plates are used to dissipate excess rotational kinetic energy, then the stopping function is achieved, but the device complexity and size increase
Solution Approach 1:
The patent extracts the essential stopping function from the complex friction-based brake system and implements it through a single deformable element. By removing the unnecessary components of conventional brake plates and compliant shafts, the invention retains only the critical energy-dissipating function in a simplified form
Solution Approach 2:
The patent employs a deformable element that is designed to be consumed or replaced after a high-speed stop event. This disposable approach allows for a simpler, lighter stopping mechanism that does not require the durability and complexity of reusable friction-based systems, as the deformable element is replaced only when needed
3Ease of operation
If upstream gears are positioned between the stop module and motor to manage stroke range, then the stroke range is controllable, but the gears must carry stopping torque increasing their load
Solution Approach 1:
The patent inverts the conventional arrangement by placing the stop module upstream near the motor rather than downstream in the gear train. This reversal allows the deformable element to absorb stopping energy directly at the motor shaft, preventing the transmission of stopping torque through the upstream gears and eliminating the need for them to carry excessive loads
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 solution effectively prevents jamming at the end stop, reduces weight and size by about 80%, eliminates torque drag and inertia, and ensures safe and quick stopping of the actuator, making it suitable for high-performance applications like aircraft control systems.
Implementation Method 1
a low inertia, deformable stopping disk or other deformable element that can safely dissipate excess rotational kinetic energy of the rotating shaft system
Data Source
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AI summary
A stop module for non-jamming end-of-stroke stoppage of a rotary drive actuator includes timing gears to articulate a stopping pawl, and a low inertia, deformable stopping disk arranged to safely dissipate excess rotational kinetic energy of the rotary actuator. The stop module does not rely on friction to stop and dissipate the excess kinetic energy, but instead relies on predictable deformation of a metallic stopping disk which may be provided in a stopping cartridge of the stop module. Use of a deformable element to dissipate excess energy allows the disclosed stop module to be lighter and smaller than conventional end-of-stroke stopping mechanisms.