Composite Torque Limiting Assembly for Stable High-Torque Slip
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Solution Overview
Problem
The industry continues to need improvements in torque limiting assemblies that can effectively limit angular movement between a shaft and a component installed on the shaft, while allowing for high torque applications and minimizing variations in torque.
Innovation Solution
A torque limiting assembly comprising a bearing with a metal substrate and a polymer layer, along with a tolerance ring that includes a plurality of projections, is designed to provide a limited interference fit between a shaft and a pulley. This assembly allows the shaft to slip when the torque exceeds a threshold, minimizing damage in high-torque applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque limiting assembly provides a limited interference fit between shaft and component, then angular movement is limited and components are protected, but torque variations increase and high torque applications are restricted
Solution Approach 1:
The bearing is segmented into two distinct materials: a metal substrate providing structural strength and a polymer layer providing torque limiting capability. This segmentation allows each material to optimize its function - the metal substrate maintains dimensional stability and reduces torque variations, while the polymer layer provides controlled slip to protect components from excessive torque
Solution Approach 2:
The bearing utilizes a composite structure combining metal and polymer materials. The metal substrate offers high strength and dimensional stability to minimize torque variations, while the polymer layer provides torque limiting through controlled deformation and slip. This composite approach resolves the contradiction by allowing the assembly to protect components while maintaining consistent torque transmission within operational limits
2Ease of manufacture
If the bearing uses a single material, then manufacturing is simpler, but it cannot effectively limit torque while maintaining dimensional stability
Solution Approach 1:
The bearing employs a composite structure with a metal substrate and polymer layer, where the metal provides dimensional stability and the polymer provides torque limiting. This composite approach maintains manufacturing feasibility through established processes like metal casting followed by polymer coating or lamination, while achieving reliable torque limiting capability that single-material bearings cannot provide
3Reliability
If the bearing allows shaft slip at high torque, then component damage is reduced, but torque transmission consistency deteriorates
Solution Approach 1:
The bearing exhibits different mechanical properties at different radial positions and under different load conditions. The polymer layer is designed with specific thickness and material properties that allow it to remain rigid under normal operating torque, ensuring consistent torque transmission. When torque exceeds the design threshold, the polymer layer locally deforms and allows controlled slip, protecting components while maintaining overall system stability through the rigid metal substrate
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 limiting assembly effectively limits angular movement and allows the shaft to slip at high torques, reducing the risk of damage to components and minimizing variations in torque, making it suitable for high-torque applications such as air conditioner compressor assemblies.
Implementation Method 1
A torque limiting assembly can be fitted around a shaft and pulley. The bearing can include a metal substrate and a polymer layer disposed on the metal substrate
Implementation Method 2
The shaft and the component formed with the bore can rotate together until a torque limit exceeded
Data Source
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AI summary
A torque limiting assembly is disclosed and can include a generally cylindrical bearing and a tolerance ring disposed around the generally cylindrical bearing. The torque limiting assembly is configured to be installed between and rotatably couple an inner and an outer component. The torque limiting assembly is configured to rotate with respect to at least one of the inner and outer components when a threshold torque, T, is exceeded.