Variable Damper for No-Back Brake Creep Inhibition
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Solution Overview
Problem
No-back brake devices in stabilizer actuator systems for aircraft experience creep due to excessive vibrations, despite the use of braking mechanisms, leading to unwanted movement of the horizontal stabilizer.
Innovation Solution
A system comprising a motor, a ballscrew assembly, a no-back brake device, and a variable damper, where the damper's damping characteristic is adjusted based on the motor's operational state to provide minimal damping during active adjustment and increased damping during standby periods to prevent creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a no-back brake device is used to resist ballscrew movement, then stability is improved, but creep occurs under excessive vibration
Solution Approach 1:
The patent applies a variable damper that dynamically adjusts its damping characteristic based on the motor's operational state. During motor operation, the damper provides minimal damping to allow free movement. During standby periods, the damper increases damping to prevent creep. This dynamic adaptation resolves the contradiction by making the damping force conditional rather than constant.
Solution Approach 2:
The patent changes the damping parameter of the damper based on the motor state. The control system monitors whether the motor is operating or in standby mode and adjusts the damper's damping coefficient accordingly. This parameter change allows the system to maintain stability during operation while preventing creep during standby periods.
2Reliability
If increased damping is applied to prevent creep, then creep resistance is improved, but movement during active adjustment is restricted
Solution Approach 1:
The variable damper dynamically switches between two damping states based on motor operation. When the motor is active, the damper transitions to a low-damping state that allows free movement for adjustment. When the motor is in standby mode, the damper transitions to a high-damping state that prevents creep. This dynamic switching resolves the contradiction between creep resistance and adjustment freedom.
Solution Approach 2:
The damper operates in periodic cycles corresponding to motor operation cycles. During active adjustment periods, damping is minimized. During standby periods between adjustments, damping is maximized. This periodic modulation of damping allows the system to alternate between ease of operation and creep prevention.
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 inhibits unwanted movement of the ballscrew assembly by providing variable viscous drag, maintaining the stabilizer in a desired position and reducing creep caused by vibrations and aerodynamic loads.
Implementation Method 1
maintaining the damper in a second state to provide a second viscous drag different from the first viscous drag to the ballscrew assembly
Data Source
AI summary
A system for inhibiting no-back brake device creep includes a motor, a ballscrew assembly coupled to the motor, a no-back brake device coupled to the ballscrew assembly, and at least one damper coupled to the ballscrew assembly. The damper varies a damping characteristic based on an operational state of the motor.