Torque Limiter Actuator for Roller Shutters
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Solution Overview
Problem
Existing electromechanical drive actuators for roller shutters face issues with electrical energy supply constraints, risk of degradation during manual operation, and potential breakage of fragile components due to excessive torque, especially when handling heavy loads like commercial grids.
Innovation Solution
An electromechanical actuator design incorporating a torque limiter that calibrates torque transmission to prevent damage by limiting torque to a reference limit, using frustoconical friction surfaces and a bidirectional coupling mechanism with elastic return members, allowing for both motor-driven and manual operation while protecting the mechanism from excessive torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bidirectional freewheel mechanism is used for manual operation, then manual driving capability is enabled, but the mechanism becomes complex and vulnerable to excessive torque damage
Solution Approach 1:
The torque transmission mechanism is divided into two independent paths: a motor-driven path with a torque limiter and a manual-driven path with a bidirectional freewheel. This segmentation allows each path to be optimized for its specific function while reducing overall system complexity and vulnerability.
Solution Approach 2:
An intermediate shaft is introduced as a mediator between the motor shaft and the load. The torque limiter couples the motor shaft to the intermediate shaft, while the bidirectional freewheel couples the secondary driving shaft to the intermediate shaft. This intermediary structure simplifies the connection and reduces complexity.
2Productivity
If the torque transmission mechanism transmits all manual torque, then manual operation effectiveness is improved, but fragile components may break due to excessive torque
Solution Approach 1:
The torque limiter is calibrated to transmit torque up to a reference limit torque, which is set below the breaking torque of the most fragile element in the transmission chain. This beforehand cushioning protects fragile components from excessive torque during manual operation while maintaining effectiveness.
3Adaptability or versatility
If the actuator casing rotates during manual operation, then manual driving is enabled, but electrical energy supply becomes constrained
Solution Approach 1:
The drive system is segmented into motor-driven operation and manual-driven operation as separate, independent modes. During manual operation, the bidirectional freewheel engages and the motor shaft is uncoupled, eliminating constraints on electrical energy supply while enabling manual driving 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
The solution ensures reliable operation by fully transmitting torque up to a reference limit, preventing damage to the actuator's fragile components and allowing safe manual operation, even with heavy loads, while integrating multiple functions into a compact design.
Implementation Method 1
The torque limiter comprises friction surfaces pressed against each other with a predetermined force
Implementation Method 2
The torque limiter comprises at least one elastic return member exerting the predetermined force
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The actuator has an electric motor that drives the load using main drive shafts. The arbitrary motor torques added to the intermediate output portion by secondary input portion is transmitted. The torque-transmission mechanism connected to secondary input portion containing fixed frame and bidirectional coupling device. The torque limiter connects the intermediate output portion to main drive shafts.