Torque Limiter with Variable Magnetic Coupling for Safety
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Solution Overview
Problem
Existing torque limiters, such as those using electromagnetic clutches, fail to ensure safety during unexpected power supply loss or emergency stops, as they interrupt power transmission, potentially leading to unintentional operation or falls, and cannot variably set the torque limit value for transmission control.
Innovation Solution
A torque limiter with an electromagnetic coupling structure that adjusts the torque limit value by varying the magnetic force through application voltage, allowing the torque limiter to switch between connected and disconnected states, ensuring safety during power losses by maintaining a controlled torque limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque limiter using an electromagnetic clutch is used to interrupt torque transmission during overload, then torque control is achieved, but safety deteriorates during unexpected power supply loss or emergency stop
Solution Approach 1:
The patent inverts the traditional electromagnetic clutch behavior by configuring it to maintain connection through residual magnetism during power loss rather than disconnecting. The electromagnetic clutch is designed so that the magnetic force naturally persists without active energization, keeping the input and output units connected during emergencies, while still enabling torque limitation during normal operation through controlled energization.
Solution Approach 2:
The patent applies beforehand cushioning by utilizing the residual magnetism of the electromagnetic clutch as a pre-prepared safety mechanism. This residual magnetic force acts as a cushion that maintains the connecting state during power supply loss, preventing sudden disconnection and the harmful effects of inertial motion before safety issues can arise.
2Adaptability or versatility
If a fixed torque limit value is used in the electromagnetic clutch, then simple control is achieved, but adaptability for various functions is lost
Solution Approach 1:
The patent applies dynamics by making the torque limit value adjustable rather than fixed. The electromagnetic clutch is designed to accept variable energization levels that dynamically change the magnetic force, thereby dynamically adjusting the torque limit value. This allows the system to adapt to different operational requirements while maintaining a relatively simple device structure.
Solution Approach 2:
The patent utilizes parameter changes by varying the energization level of the electromagnetic clutch to change the magnetic force and consequently the torque limit value. By changing the electrical parameter (energization level), the mechanical parameter (torque limit) is adjusted, enabling versatile torque control without complex mechanical adjustments.
3Device complexity
If the electromagnetic clutch disconnects during power loss, then torque transmission is interrupted, but additional safety devices are required
Solution Approach 1:
The patent applies universality by making the electromagnetic clutch perform multiple functions: torque limitation during normal operation and safety maintenance during power loss. The same electromagnetic clutch component serves both as a torque control device and as an emergency safety device, eliminating the need for separate safety mechanisms and simplifying the overall configuration.
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 torque limiter effectively varies the torque limit value, enhancing safety and control during power supply disruptions, eliminating the need for additional emergency brakes and simplifying configurations by using the driving device's resistance to brake the output side.
Implementation Method 1
The coupling structure includes an electromagnet that enables adjustment of the magnetic force through adjustment of an application voltage
Implementation Method 2
power transmission from the input side to the output side by the electromagnetic clutch is interrupted in an non-energized state
Data Source
AI summary
A torque limiter 10 includes an input unit 11 connected to a driving device M on input side, and an output unit 12 connected to a robot arm A on output side. The input unit 11 and the output unit 12 include a coupling structure in which the input unit 11 and the output unit 12 approach and recede from each other so as to enable switching of a connecting state where the input unit 11 and the output unit 12 are connected to each other and a non-connecting state where the input unit 11 and the output unit 12 are not connected to each other, through adjustment of magnetic force therebetween. The coupling structure includes an electromagnet 17 that enables adjustment of the magnetic force through adjustment of an application voltage.