Decoupling Sleeve Unscrewing Nut for Reverse Torque Protection
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Solution Overview
Problem
Existing decoupling sleeves in turbine engines are fragile and prone to untimely fractures due to misalignments and parasitic reverse torques, reducing reliability as they rely on thin fracture zones in traction or torsion for reverse torque decoupling.
Innovation Solution
A decoupling sleeve with a mobile nut connected by screwing to a coaxial shaft, which unscrews upon reverse torque exceeding a threshold, using a return spring and limited angular rotation to detach the dog clutch jaws, eliminating the need for a frangible rod and enhancing robustness against parasitic loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frangible rod with fracture zones is used for reverse torque decoupling, then the decoupling function is achieved, but the device becomes fragile and sensitive to misalignments and parasitic torques
Solution Approach 1:
The invention changes the failure mode from fracture (binary, sensitive to defects) to controlled unscrewing (gradual, predictable). The connecting member transitions from a rigid rod with fracture zones to a threaded assembly where the nut can rotate and unscrew in a controlled manner under reverse torque, providing a more reliable and less fragile decoupling mechanism
Solution Approach 2:
The invention introduces dynamic movement to the connecting member. Instead of a static rod that fractures, the nut can move axially and rotate relative to the shaft, allowing controlled unscrewing under reverse torque. This dynamic capability makes the system more robust as it can accommodate misalignments and parasitic torques through controlled motion rather than brittle failure
2Adaptability or versatility
If thin fracture zones are provided on the frangible rod, then reverse torque decoupling is enabled, but the device becomes sensitive to misalignments and parasitic reverse torques
Solution Approach 1:
The invention introduces a threaded connection as an intermediary mechanism between the connecting member and the shaft. This threaded interface acts as a mediator that can controlledly fail through unscrewing under reverse torque, providing a more robust and predictable decoupling mechanism that is less sensitive to parasitic loads and misalignments compared to direct fracture zones
Solution Approach 2:
The threaded connection allows the nut to move and rotate dynamically under reverse torque, providing controlled unscrewing rather than brittle fracture. This dynamic failure mode is more tolerant of misalignments and parasitic torques, reducing sensitivity to harmful factors while maintaining decoupling capability
3Reliability
If the decoupling sleeve uses a frangible rod with fracture zones, then reverse torque protection is achieved, but the device requires precise alignment and is prone to untimely fractures
Solution Approach 1:
The invention changes the failure mechanism from fracture (sensitive to alignment and defects) to controlled unscrewing (tolerant of misalignment). The threaded connection allows for gradual separation under reverse torque, providing a more reliable and less precision-critical decoupling mechanism that reduces untimely fractures
Solution Approach 2:
The threaded connection serves as an intermediary that provides controlled, gradual separation under reverse torque. This mediator mechanism is more tolerant of manufacturing imperfections and alignment variations compared to direct fracture zones, reducing the need for high manufacturing precision while maintaining operational reliability
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 significantly reduces sensitivity to parasitic loads and misalignments, ensuring reliable decoupling by measuring reverse torque through the force required to open the dog clutch jaws, thereby enhancing the robustness and reliability of the decoupling mechanism.
Implementation Method 1
a return spring (10) acting on the nut (20) in order to push it back along the rod (8)
Implementation Method 2
The connecting member (8, 20) is connected by screwing to a nut (20)
Data Source
AI summary
The invention relates to a decoupling sleeve having driving and driven shafts connected by dog clutches. The driving shaft transmits torque to the driven shaft in one direction during a forward direction of rotation where a rod-shaped connecting member is connected to two shafts so that the connecting member is detached from one of the shafts if subject to a reverse torque beyond a specific threshold. The two shafts become free in rotation relative to one another upon this detachment.