Electromagnetic Torque Limiter Assembly for Precise Overload Braking
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Solution Overview
Problem
Conventional torque limiter systems fail to effectively manage excessive torque between drive and driven shafts, potentially causing damage due to lack of precise control and distributed stress management.
Innovation Solution
A torque limiter assembly featuring a torque sensor and electromagnet-activated engagement members, such as teeth projections on the housing and input shaft, which engage to halt rotation when excessive torque is detected, utilizing a magnetic field to overcome a biasing force and distribute contact stress, allowing for adjustable activation thresholds and minimal inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional torque limiter systems are used to prevent excessive torque, then damage to the apparatus is prevented, but the systems lack precise control and distributed stress management
Solution Approach 1:
The torque limiter is divided into multiple independent engagement members (first engagement members on the housing and second engagement members on the input shaft) distributed around the circumference. This segmentation allows stress to be distributed across multiple contact points rather than concentrated at a single location, improving reliability while maintaining a relatively simple overall structure.
Solution Approach 2:
An electromagnet is introduced as an intermediary component between the control system and the engagement members. The electromagnet enables precise control of the engagement and disengagement timing by converting electrical signals into magnetic forces that act on the engagement members, thereby achieving precise torque control without requiring complex mechanical control mechanisms.
2Reliability
If engagement members are used to halt rotation when excessive torque is detected, then torque is effectively limited, but the system requires rapid engagement and disengagement
Solution Approach 1:
The traditional mechanically-actuated engagement mechanism is replaced with an electromagnet-based system. The electromagnet can be activated and deactivated rapidly through electrical signals, enabling fast engagement and disengagement of the torque limiter without the inertia and mechanical complexity of traditional spring-loaded or cam-based mechanisms.
Solution Approach 2:
The engagement members are designed to be movable rather than fixed, allowing them to dynamically engage and disengage based on real-time torque conditions. The electromagnet provides dynamic control capability, enabling the system to respond quickly to changing torque loads and adjust the engagement state accordingly.
3Stress or pressure
If multiple engagement members are distributed around the input shaft, then contact stress is distributed, but the device complexity increases
Solution Approach 1:
The torque limiting function is segmented into multiple engagement members distributed circumferentially around the input shaft. This segmentation distributes the contact stress across multiple points during engagement, preventing stress concentration at any single location and improving the durability of the torque limiter components.
Solution Approach 2:
Multiple engagement members are combined into a coordinated system controlled by a single electromagnet. Rather than requiring separate actuators for each engagement member, the electromagnet provides centralized control that simultaneously actuates all engagement members, reducing the overall number of components and simplifying the control architecture while maintaining stress distribution benefits.
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
Effectively limits torque to prevent damage by engaging and disengaging the shafts based on sensed torque levels, providing controlled braking with distributed stress and reduced inertia, while allowing for easy adjustment of activation thresholds.
Implementation Method 1
an electromagnet (10) arranged on the housing (4) and a controller (15) for controlling the voltage supply based on the level of torque sensed by the torque sensor (8). In use, the electromagnet (10) generates a magnetic field that moves the at least one engagement member into engagement with the other at least one engagement member
Data Source
Figure 1
AI summary
A torque limiter assembly is disclosed comprising a housing 4 having at least one first engagement member 6, an input shaft 2 that is rotatable relative to the housing 4 and having at least one second engagement member 16; and an electromagnet 10. The electromagnet 10 is arranged and configured such that when activated it generates a magnetic field that moves the at least one first engagement member 6 relative to the at least one second engagement member 16, such that the first and second engagement members engage each other and stop or inhibit rotation of the input shaft 2 relative to the housing 4.