No-Back Brake Damper Assembly for Chatter Suppression
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Solution Overview
Problem
No-back brakes in aircraft actuators are susceptible to chatter, leading to vibration, audible noise, and large torque oscillations, which degrade performance and increase maintenance costs.
Innovation Solution
A no-back brake system with a limited authority damper assembly, comprising an outer spacing ring, inner damping ring, and springs, is introduced to reduce chatter by providing a parallel load path and controlled torque transmission between the drag and main brake assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a no-back brake system is used to protect against back-driving in aircraft actuators, then reliability is improved, but chatter occurs causing vibration, audible noise, and torque oscillations
Solution Approach 1:
A damper assembly is introduced as an intermediary component between the drag brake assembly and the main brake assembly. This damper includes a damper spring that selectively engages to provide a parallel load path, absorbing vibrations and reducing chatter while maintaining the no-back brake's primary function of preventing back-driving during loading operations.
Solution Approach 2:
The damper spring modifies the stiffness and damping characteristics of the brake system by selectively engaging and disengaging based on load conditions. This parameter change allows the system to transition between different operational states, reducing torque oscillations and chatter while maintaining reliability.
2Device complexity
If the drag brake assembly and main brake assembly are separated by a spacer, then structural simplicity is maintained, but chatter vibrations are not sufficiently damped
Solution Approach 1:
The damper assembly serves as an intermediary between the drag and main brake assemblies, replacing or augmenting the simple spacer. This intermediary component actively dampens vibrations and chatter while maintaining the separated structure of the brake assemblies, thus not significantly increasing device complexity while effectively reducing harmful vibrations.
Solution Approach 2:
The damper spring is pre-configured to provide cushioning before chatter and vibrations occur. By being positioned between the brake assemblies with predetermined engagement characteristics, it proactively absorbs shock and dampens oscillations before they can propagate through the system.
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 system significantly reduces chatter, stabilizing the driveline system and improving performance and safety by limiting torque oscillations and vibrations.
Implementation Method 1
a first spring disposed between the outer spacing ring and the inner damping ring
Implementation Method 2
a second spring disposed between the outer spacing ring and the main brake assembly
Data Source
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AI summary
A no-back brake system for an actuator includes a ball ramp mechanism. A drag brake assembly is configured to be coupled to a first portion of the ball ramp mechanism. A main brake assembly is configured to be coupled to the actuator and a second portion of the ball ramp mechanism. A limited authority damper assembly is disposed between the drag brake assembly and the main brake assembly. The limited authority damper assembly includes an outer spacing ring configured to be coupled to the drive shaft of the actuator, an inner damping ring coupled to the outer spacing ring and the drag brake assembly, and a first spring disposed between the outer spacing ring and the inner damping ring.