Ball Nut Lock Assembly for Lightweight Linear Actuator Locking
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Solution Overview
Problem
Conventional locking mechanisms for linear actuators, such as those used in hydraulic thrust reverser actuation systems, are heavy, costly, and require frequent maintenance, making them unsuitable for the transition to electrically actuated systems in the aircraft industry.
Innovation Solution
A lock assembly for linear actuators featuring a ball nut with axial lock protrusions and a lock rotor with inward ridge protrusions, allowing independent electrical control and automatic locking without power, utilizing springs for biasing and mass balancing to prevent vibration, with manual unlocking options for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic locking mechanisms are used for linear actuators, then reliable locking is achieved, but weight increases and maintenance requirements increase
Solution Approach 1:
The patent replaces the hydraulic locking system with an electrically actuated mechanical locking system. The electric motor-driven ball screw mechanism with lock protrusions and ridge protrusions provides reliable locking without the weight and maintenance issues of hydraulic systems, directly resolving the contradiction between reliability and weight.
Solution Approach 2:
The locking mechanism is designed to automatically lock when power is removed, using spring biasing to engage the lock protrusions with the ridge protrusions. This self-locking feature ensures reliability without requiring continuous power or complex control systems, reducing overall system weight while maintaining secure positioning.
2Reliability
If hydraulic locking mechanisms are used for linear actuators, then locking function is achieved, but system complexity and cost increase
Solution Approach 1:
The patent substitutes complex hydraulic locking components with a simpler electrically actuated mechanical system consisting of a ball screw, lock rotor, and spring mechanism. This reduces system complexity while maintaining the locking function, directly addressing the contradiction between reliability and device complexity.
3Reliability
If conventional locking mechanisms are used, then positioning is achieved, but vibration occurs during operation
Solution Approach 1:
The patent employs dynamic balancing of the ball screw assembly and uses controlled acceleration and deceleration profiles during positioning operations. The spring-biased locking mechanism provides smooth engagement that minimizes vibration, while the electric motor allows for controlled motion that prevents resonant vibrations, resolving the contradiction between positioning accuracy and vibration.
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 provides a robust, electrically actuated locking mechanism that is lightweight, cost-effective, and resistant to damage, ensuring reliable operation and easy maintenance, aligning with the shift towards more electric aircraft platforms.
Implementation Method 1
A lock assembly for a linear actuator includes a ball nut, a lock rotor configured to encircle the ball nut, and a spring configured to apply a locking bias force to the lock rotor
Implementation Method 2
In a lock position, the ridge protrusions are arranged between locking protrusions along the row of lock protrusions
Data Source
AI summary
Methods and systems for a lock assembly for a linear actuator. The lock assembly includes a ball nut having one or more rows of lock protrusions extending axially from an external circumference of the ball nut. A lock rotor encircles the ball nut, the lock rotor having a row of ridge protrusions extending axially inward from an internal circumference. In a lock position, the ridge protrusions are arranged between locking protrusions. In an unlocked position, the ridge protrusions are arranged between adjacent locking protrusions.