Torque Limiter Transmission With Dual Coupling Assemblies
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Solution Overview
Problem
Existing torque limiting devices for aircraft high-lift flap systems fail to effectively lock the flaps when a predetermined torque threshold is exceeded while ensuring reversible operation, as they either do not lock reliably or unlock prematurely.
Innovation Solution
A torque limiting transmission device with a housing, input and output shafts, a brake, and dual coupling assemblies that move between released and clamped configurations based on torque thresholds, allowing for precise control of torque transmission and reversible operation by using different coupling mechanisms and elastic return members to manage torque and prevent over-rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single coupling mechanism with a predetermined torque threshold is used, then torque limitation is achieved, but reliable locking and reversible unlocking cannot be simultaneously ensured
Solution Approach 1:
The single coupling mechanism is divided into two separate coupling mechanisms: a first coupling mechanism (15) with a first torque threshold for reliable locking, and a second coupling mechanism (35) with a second torque threshold for reversible unlocking. This segmentation allows each mechanism to be optimized for its specific function, resolving the contradiction between locking reliability and reversible operation.
Solution Approach 2:
Each coupling mechanism is given different local properties: the first coupling mechanism has a higher torque threshold and stiffer elastic return member for secure locking, while the second coupling mechanism has a lower torque threshold and more compliant elastic return member for easy unlocking. This local differentiation enables simultaneous achievement of reliable locking and reversible operation.
2Reliability
If the torque threshold for brake activation is set high to ensure effective locking, then locking reliability improves, but the brake may not activate in time to prevent damage
Solution Approach 1:
The second coupling mechanism activates the brake in advance at a lower torque threshold before the first coupling mechanism reaches its higher threshold. This preliminary action prevents torque overload damage by engaging the brake early, while the first coupling mechanism provides the final secure locking at the higher threshold.
3Strength
If a torque limiting device with high stiffness is used to ensure firm locking, then locking strength improves, but the device becomes less sensitive to torque changes for reversible operation
Solution Approach 1:
The torque limiting device is segmented into two coupling mechanisms with different stiffness characteristics. The first coupling mechanism uses a stiffer elastic return member for strong locking, while the second coupling mechanism uses a more compliant elastic return member for sensitive torque detection and reversible operation.
Solution Approach 2:
Different local stiffness properties are assigned to each coupling mechanism: the first coupling mechanism has high stiffness for strong locking force, while the second coupling mechanism has lower stiffness for sensitive detection of torque changes, enabling precise control of brake activation and deactivation.
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 device ensures effective blocking of torque when the input torque exceeds the threshold while allowing reversible operation by using a low second threshold for the second coupling assembly to control the brake, ensuring reliable locking and unlocking based on torque levels.
Implementation Method 1
the first coupling mechanism comprises a first elastic return member suitable for biasing the first input part towards the first position, the second coupling mechanism comprises a second elastic return member capable of biasing the second input part towards the first position
Implementation Method 2
a brake between the housing and the output shaft, the brake being movable between a released configuration in which the brake permits rotation of the output shaft relative to the housing and a clamped configuration in which the brake prevents rotation of the output shaft relative to the housing
Data Source
Figure 1~3
Figure 4
Figure 5
AI summary
The invention relates to a transmission device (1) including: - a housing (2), - an input shaft (3) rotatably mounted relative to the housing (2), - an output shaft (4) rotatably mounted relative to the housing (2), - a brake (12) between the housing (2) and the output shaft (4), - a first coupling assembly (9) that is movable between a first coupling position when the torque transmitted by the input shaft (3) is below a first threshold, and a second coupling position when the torque transmitted by the input shaft is greater than the first threshold, - a second coupling assembly (11) making it possible to apply the brake (12) when the first coupling assembly (9) is in the second position.