Aerostructure Actuation Slip Clutch for Excessive Torque Decoupling
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Solution Overview
Problem
Aerostructures in aircraft are prone to damage due to excessive torque and load during high-load events, which can exceed aircraft limit loads, leading to potential self-damage from the actuator system's drive shaft.
Innovation Solution
An integrated driveline slip-clutch system is implemented within the actuator system, featuring a clutch assembly with a post, bearings, a spacer, and a load setting nut that decouples the shafts if the relative rotational speed exceeds a predefined limit, preventing excessive torque transmission and protecting the aerostructures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional actuator system with a drive shaft is used to control aerostructures, then the aerostructure can be actuated, but the aerostructure is prone to damage from excessive torque during high-load events
Solution Approach 1:
A clutch assembly is introduced as an intermediary component between the drive shaft and the aerostructure. This clutch assembly includes a friction element that can engage and disengage to control torque transmission. When excessive torque is detected, the clutch assembly slips or disengages, preventing the excessive torque from reaching the aerostructure while still allowing normal operation under acceptable load conditions.
Solution Approach 2:
The clutch assembly changes the torque transmission parameter dynamically. During normal operation, it transmits full torque efficiently. When the torque exceeds a predetermined threshold, the friction element overheats or wears, causing the clutch to slip and reduce torque transmission to a safe level, thus protecting the aerostructure from damage.
2Volume of moving object
If the clutch assembly is integrated within the mandrel of the drive shaft, then the system remains compact, but the device complexity increases
Solution Approach 1:
The clutch assembly is nested within the hollow interior of the mandrel, utilizing the existing internal space of the drive shaft. This nesting approach allows the clutch mechanism, including the friction element and actuating components, to be housed inside the mandrel without significantly increasing the external dimensions of the actuator system, thereby maintaining a compact overall volume while adding the protective functionality.
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 slip-clutch system effectively prevents damage by decoupling the drive shafts before reaching the aircraft's limit load, reducing the risk of self-damage to aerostructures and maintaining system integrity during high-load conditions.
Implementation Method 1
a load setting nut configured to threadedly engage with the post extension and apply a compressive force to the first bearing, spacer, and the second bearing against the post
Implementation Method 2
each of the first bearing and the second bearing comprise an inner race, an outer race, and one or more bearing elements arranged therebetween
Implementation Method 3
a portion of the first bearing frictionally engaging with a portion of the post
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Aerostructure actuator systems include first and second shaft portions (302, 304) having respective first and second mandrels (308, 310) and a clutch assembly (306) arranged within the first mandrel (308) and connecting the shaft portions (302, 304). The clutch assembly (306) includes a post (312) with a post extension (412) fixedly connected to the second mandrel (310). A first bearing (314) is installed on the post extension to frictionally engage with a portion of the post. A second bearing (318) is installed on the post. A spacer (316) is arranged between the bearings and is fixedly attach to the first mandrel. A load setting nut (322) is configured to engage with the post extension and apply a compressive force to the bearings and spacer against the post. The compressive force defines a coupling limit between the shaft portions. The clutch assembly (306) is configured to rotationally decouple the shaft portions from each other if a relative rotational speed between the shaft portions exceeds the coupling limit.