Spindle Drive Redundancy via Dual Nuts and Sensor
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Solution Overview
Problem
Existing spindle drives in aircraft components lack redundancy, making them non-functional if one load path fails, which can compromise aircraft control during flight.
Innovation Solution
A spindle drive design with dual load paths, where a second nut is movable relative to the first nut, and a sensor unit detects relative movement to indicate defects, allowing actuation through the intact path and alerting users to failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single load path is used in the spindle drive, then the device complexity is reduced, but the reliability deteriorates because the system becomes non-functional if the load path fails
Solution Approach 1:
The single load path is segmented into two independent load paths (first nut and second nut), each capable of independently transmitting force from the threaded bolt to the component. This segmentation allows the system to maintain functionality even if one path fails, thereby improving reliability without significantly increasing overall device complexity.
Solution Approach 2:
The second nut is positioned in a different axial region of the threaded bolt compared to the first nut. This local differentiation in positioning creates independent load paths that can fail independently, providing redundancy at specific locations while maintaining the overall simplicity of the spindle drive structure.
2Difficulty of detecting and measuring
If a sensor unit is added to detect relative movement between nuts, then the ability to detect defects is improved, but the device complexity increases
Solution Approach 1:
A sensor unit is introduced as an intermediary element that detects the relative axial movement between the first and second nuts. This mediator converts the mechanical state (relative position) into a detectable signal, enabling defect detection without fundamentally altering the load path mechanics. The sensor provides critical information while adding minimal complexity compared to the mechanical components.
Solution Approach 2:
The sensor unit provides feedback about the relative movement between nuts, which can indicate wear or failure in one of the load paths. This feedback mechanism enables continuous monitoring of the spindle drive's health status, allowing for early detection of defects and maintaining system reliability through timely intervention.
3Reliability
If the second nut is positioned outside the operating region, then the redundancy is improved, but the productivity may deteriorate due to increased axial travel distance
Solution Approach 1:
The second nut is positioned in a different axial dimension relative to the first nut, specifically in a region that is at least partially outside the operating region. This spatial arrangement in another dimension provides geometric redundancy - the second nut can engage with the threaded bolt in a region that the first nut does not occupy, ensuring that if one path fails, the other remains available without requiring significant additional axial travel.
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
Ensures continued functionality of the spindle drive by detecting and mitigating failures through the second load path, maintaining aircraft control even if one path fails, and providing real-time defect indication.
Implementation Method 1
a sensor unit which is made such that it detects a relative movement between the first nut and the second nut
Implementation Method 2
a first nut which meshes with a threaded bolt and a second load path which includes a second nut which likewise meshes with the threaded bolt
Data Source
AI summary
A spindle drive has a first load path formed by a first nut which meshes with a threaded bolt and a second load path formed by a second nut which also meshes with the threaded bolt and is arranged to be movable relative to the first nut in an axial direction of the threaded bolt in at least one state of the spindle drive. A sensor unit detects relative movement between the first and second nuts.