Spacecraft Joint Device With Overrunning Clutches
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Solution Overview
Problem
Existing joint devices for spacecraft structures, particularly large antenna masts, are not resilient enough to handle significant mass-inertia forces and often fail under shock loads due to limited design for small forces.
Innovation Solution
A joint device with a pivot shaft connected to two drive devices, each equipped with an overrunning clutch, allowing for redundant operation and decoupling in case of failure, along with a locking mechanism to secure the structure in place, ensuring reliable unfolding and stability even under heavy loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing joint devices are used for unfolding spacecraft structures, then the device complexity is reduced, but the reliability deteriorates under considerable mass-inertia forces and shock loads
Solution Approach 1:
The drive system is segmented into multiple independent drive devices (at least two), each capable of independently driving the pivot shaft. This segmentation allows the system to maintain functionality even if one drive device fails, thereby improving reliability without requiring a completely complex redundant system design.
Solution Approach 2:
Overrunning clutches are incorporated into each drive device as a preventive measure against drive device failures. These clutches automatically engage to protect the drive devices from overload and damage during unexpected shock loads or malfunctions, cushioning the system against potential failures before they occur.
2Reliability
If redundant drive devices are implemented, then the reliability improves, but the device complexity increases
Solution Approach 1:
The overrunning clutches are designed to automatically engage and disengage based on the operational state of the drive devices, without requiring external control or intervention. This self-service mechanism simplifies the control system and reduces overall device complexity while maintaining the redundancy benefits.
Solution Approach 2:
Multiple drive devices are merged into a single functional unit that drives the pivot shaft through common mechanical elements (gears, shafts). This merging approach allows the system to achieve redundancy while sharing common components, thereby reducing the overall complexity compared to completely separate drive systems.
3Reliability
If overrunning clutches are used to decouple defective drive devices, then the reliability improves, but the manufacturing precision requirements increase
Solution Approach 1:
The overrunning clutches are designed with adjustable engagement parameters (such as spring preload and engagement force) that can be optimized to balance the decoupling functionality with acceptable manufacturing tolerances. This allows the system to achieve reliable defect isolation without requiring extremely tight manufacturing precision.
4Strength
If the joint device is designed for considerable mass-inertia forces, then the strength improves, but the weight of the device increases
Solution Approach 1:
The joint device incorporates dynamic elements such as overrunning clutches and spring-based locking mechanisms that provide strength and shock absorption only when needed during deployment or under load conditions. During normal operation, these elements remain passive, allowing the device to maintain adequate strength while minimizing unnecessary weight.
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 joint device provides reliable and secure unfolding of heavy structures, capable of withstanding considerable mass-inertia forces and shock loads, ensuring the structure remains stable and securely deployed.
Implementation Method 1
The drive devices each comprise an overrunning clutch (i.e., a freewheel) connected to the pivot shaft. The overrunning clutches enable the defective drive device to be decoupled from the pivot shaft.
Implementation Method 2
An overrunning clutch can, for example, be frictionally connected to the pivot shaft.
Implementation Method 3
a stop; the second leg can then comprise a stop surface configured to abut the stop upon corresponding pivoting of the second leg
Data Source
Figure 1
Figure 2~3
AI summary
A hinge device 100 for unfolding a structure on a spacecraft is disclosed. The hinge device comprises a first leg (10), a second leg (20), a pivot shaft (30) which is rotatably mounted on the first leg (10) about its central longitudinal axis X and connected to the second leg (20), and at least two drive devices (40, 40') each for causing rotation of the pivot shaft (30) in at least one direction of rotation. The drive devices (40, 40') each have an overrunning clutch (43) which is connected to the pivot shaft (30). A spacecraft with a hinge device (100) is also disclosed.