Actuator Lock Nut Assembly for In-Situ Torque Adjustment
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Solution Overview
Problem
In helicopter rotor actuators, the existing lock nut assemblies require frequent disassembly for torque checking and adjustment, leading to increased maintenance time, cost, and risk of Foreign Object Damage (FOD) due to the need to replace deformable components.
Innovation Solution
A lock nut assembly with a retaining and release mechanism that allows in-situ torque checking and adjustment without disassembly, featuring a nut configured for axial movement and a pin mechanism that can be moved between engaged and unlocked positions to enable rotation and secure the nut relative to the bracket.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock nut is designed to be fixed securely to maintain torque, then the reliability is improved, but the ease of operation for torque checking and adjustment deteriorates
Solution Approach 1:
The lock nut assembly is segmented into two functional parts: a locking mechanism that secures the nut during operation, and a release mechanism that enables temporary access for torque adjustment. This segmentation allows the system to maintain reliability during normal operation while enabling ease of maintenance when needed.
Solution Approach 2:
The lock nut assembly transitions from a static fixed state during operation to a dynamic accessible state during maintenance. The release mechanism allows the assembly to change state temporarily for torque checking, then return to the fixed state, providing both reliability and operational flexibility.
2Ease of repair
If the actuator assembly is disassembled for lock nut adjustment, then the torque can be checked and adjusted, but the loss of time and productivity deteriorates
Solution Approach 1:
The assembly is segmented to allow access to the lock nut without disassembling the entire actuator. The release mechanism is positioned and designed to enable direct access to the nut, separating the maintenance function from the complete assembly disassembly process.
Solution Approach 2:
The locking function is extracted as a separate controllable mechanism that can be temporarily disengaged without removing the nut from the assembly. This allows torque adjustment to be performed in-situ by simply actuating the release mechanism rather than disassembling the entire actuator.
3Ease of manufacture
If traditional fastening components are used, then the manufacturing is simpler, but the risk of FOD and damage increases
Solution Approach 1:
The release mechanism incorporates a deformable component designed for single-use or limited-use cycles. This component is intentionally designed to be replaceable and is positioned to contain any potential FOD within the assembly, protecting critical components while maintaining manufacturing simplicity.
Solution Approach 2:
The deformable component acts as an intermediary between the release mechanism and the lock nut. It provides the necessary mechanical function while containing any potential FOD within the assembly, mediating between the need for simple manufacturing and the requirement to minimize FOD risk.
Data Source
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AI summary
A lock nut assembly for an actuator, the lock nut assembly comprising a nut (50) configured to be mounted to a bracket of the actuator for axial movement relative to the bracket, and a lock nut retaining and release mechanism (60) configured to be fixedly mounted to the bracket and axially movable between a first engaged position in which the lock nut retaining and release mechanism (60) engages with the nut to prevent rotation of the nut and a second unlocked position in which the lock nut retaining and release mechanism (60) is not engaged with the nut and the nut can be rotated relative to the bracket.