Shaft Decoupler Preventing Backdriving in Electric Generators
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Solution Overview
Problem
In the context of driving mechanisms like gas turbine engines and electric generators, there is a need to decouple the driving mechanism from rotating equipment to prevent further damage in case of failure, as existing solutions are inefficient and may cause additional damage if not properly disconnected.
Innovation Solution
A backdrive decoupler assembly is introduced, comprising a coupler housing, a carrier, a member with a catch, and an actuator that moves the member between engaged and decoupled positions to disconnect torque transfer between the input and output shafts, utilizing retractable balls or a strike mechanism to ensure safe disengagement during overrunning conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a decoupler assembly is implemented to prevent backdriving and damage, then system reliability and safety are improved, but device complexity increases due to additional components
Solution Approach 1:
The decoupler assembly merges the clutch mechanism and brake mechanism into a single integrated unit that shares common components such as the piston, balls, and housing. This consolidation achieves the dual functions of preventing backdriving and controlling rotational motion without proportionally increasing device complexity, as the merged assembly uses shared components rather than separate independent systems.
2Object-affected harmful factors
If existing decoupler solutions are used, then damage prevention is attempted, but additional damage may occur if disengagement is not proper
Solution Approach 1:
The decoupler assembly performs preliminary disengagement actions before complete failure occurs. The clutch mechanism selectively disengages the input shaft from the output shaft in advance of catastrophic failure, while the brake mechanism prepares to control rotational speed. This preliminary action prevents the need for forceful emergency disengagement that could cause additional damage to shafts or connected equipment.
Solution Approach 2:
The brake mechanism provides beforehand cushioning by controlling the rotational speed of the output shaft before complete stoppage is required. This gradual deceleration cushions the stopping process, preventing sudden impacts or shocks that could damage the shafts or connected rotating equipment during the decoupling and shutdown sequence.
3Reliability
If a decoupler assembly with multiple mechanisms is used, then damage prevention capability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The clutch mechanism and brake mechanism are merged into a single decoupler assembly that uses shared components including the piston, balls, springs, and housing. This consolidation reduces the total number of parts that need to be manufactured and assembled separately, lowering manufacturing complexity and cost while maintaining both damage prevention capabilities simultaneously.
Solution Approach 2:
The piston and balls serve multiple functions within the decoupler assembly: they engage and disengage the clutch mechanism while also controlling the brake mechanism. This multi-functionality reduces the number of specialized components needed, simplifying manufacturing processes and reducing overall assembly complexity while achieving comprehensive damage prevention.
Data Source
AI summary
A decoupler assembly for disengaging a shaft transmitting torque between a rotatory engine and an electric generator. The decoupler assembly includes an output shaft, input shaft wherein the output shaft is selectively coupled to the input shaft. Retractable balls are incorporated into the assembly in order to couple and decouple the input shaft from the output shaft.