Offset Starter Clutch Reengagement Without Unnecessary Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional clutch systems for gas turbine engines suffer from unnecessary rotation and heat generation when the starter motor is not needed, leading to component fatigue and efficiency losses, and active clutch arrangements add weight and complexity with a risk of failure.
Innovation Solution
A passive clutch assembly that disengages the starter motor from the accessory gearbox when torque exceeds a threshold, using axial offset permanent magnets for reengagement, and includes a helical spline/hub arrangement for efficient rotational motion transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the starter motor remains coupled to the accessory gearbox, then the motor can be readily reengaged when needed, but the motor undergoes unnecessary rotation and generates heat when not needed, leading to component fatigue and efficiency losses
Solution Approach 1:
The clutch assembly dynamically transitions between engaged and disengaged states based on operational needs. The passive disengagement mechanism allows the clutch to automatically separate when torque exceeds a threshold, preventing unnecessary rotation and heat generation while maintaining readiness for reengagement through the active reengagement capability.
2Ease of operation
If an active clutch arrangement is used to control engagement, then precise control over starter motor coupling is achieved, but the system adds weight and complexity with additional components and potential failure points
Solution Approach 1:
The clutch assembly performs self-service through its passive disengagement mechanism. When torque from the starter motor exceeds a predetermined threshold, the clutch automatically disengages without requiring external control systems, actuators, or complex mechanisms. This eliminates the need for additional weight and complexity while maintaining effective control over engagement.
3Productivity
If the starter motor is continuously coupled to the accessory gearbox, then immediate reengagement is possible, but component fatigue increases and efficiency decreases due to unnecessary rotation
Solution Approach 1:
The clutch assembly implements periodic action by alternating between engaged and disengaged states. The motor couples to the gearbox only when starting torque is needed, disengages when torque exceeds the threshold, and can be reengaged when needed again. This periodic engagement pattern reduces component fatigue and extends life while maintaining productivity through rapid reengagement capability.
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
Reduces unnecessary rotation and heat generation, prolongs component life, and eliminates the need for complex actuation systems, while maintaining efficient engagement and disengagement of the clutch.
Implementation Method 1
The first shaft includes a set of offset permanent magnets configured to generate an axial force to actively reengage the first clutch member with the second clutch member
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
In examples, a clutch assembly includes a first clutch member disposed near a first end of a first shaft. The first clutch member defines a first surface. The first shaft includes a starter motor coupled to a second end of the first shaft. The clutch assembly includes a second clutch member disposed near a first end of a second shaft. The second clutch member defines a second surface opposing the first surface, and the second shaft includes an accessory gearbox of a gas turbine engine coupled to a second end of the second shaft. The surfaces of the first and second clutch member engage such that rotational motion is transferred between the first clutch member and the second clutch member. The first clutch member and the second clutch member are configured to passively disengage from each other and actively reengage with each other.