Torque Limiter Curved Engagement Surface High-Speed Operation
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Solution Overview
Problem
Existing torque limiters fail to operate effectively at high speeds without damaging the mechanism or causing noise and wear, as they experience severe shock loads and deformation, leading to premature failure and changes in torque levels, especially in applications like tunneling and mining where access is limited.
Innovation Solution
The torque limiter employs a specifically curved engagement surface defined by a polynomial function, preferably of the eighth power, to minimize dynamic loads and stresses, using rocker arm-roller assemblies that maintain engagement without complete ascent until a preset torque is exceeded, thereby reducing noise and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional torque limiters are used at high speeds, then torque limiting function is provided, but severe shock loads cause deformation and premature failure
Solution Approach 1:
The patent applies curved engagement surfaces with specific geometric profiles (circular arcs, parabolas, ellipses, or higher-order curves) to replace conventional flat or sharp-edged surfaces. This curvature design gradually transitions the follower elements over the lobes during rotation, eliminating sudden impacts and shock loads that occur with conventional designs, thereby enabling reliable high-speed operation.
Solution Approach 2:
The patent modifies the geometric parameters of the engagement surfaces by defining them through specific mathematical functions (circular arcs, parabolas, ellipses, or higher-order curves). These parameter changes in surface geometry control the acceleration and deceleration profiles of follower elements, reducing dynamic loads and preventing deformation even at high rotational speeds.
2Extent of automation
If friction type torque limiters are used, then automatic resetting is achieved, but repeated heating causes clutch capacity to fade and continuous slipping
Solution Approach 1:
The patent replaces the friction-based mechanical slipping mechanism with a positive engagement mechanism using curved lobes and follower elements. Instead of relying on friction heat generation and thermal expansion for resetting, the system uses mechanical geometry where followers are guided over curved surfaces, eliminating continuous friction heating while maintaining automatic resetting capability through the mechanical engagement-disengagement cycle.
3Force
If ball-detent reset torque limiters are used, then preset torque release is achieved, but sudden acceleration changes produce stresses exceeding elastic limits
Solution Approach 1:
The patent uses smoothly curved engagement surfaces (circular arcs, parabolas, ellipses, or higher-order curves) to replace the sudden engagement geometry of ball-detent mechanisms. The curved profiles ensure that follower elements accelerate and decelerate gradually as they traverse the lobes, eliminating the abrupt acceleration changes that generate stresses exceeding elastic limits in conventional ball-detent designs.
4Productivity
If high speed operation is implemented, then productivity is increased, but severe shock loads cause deformation and failure
Solution Approach 1:
The patent defines engagement surfaces using specific mathematical functions (circular arcs, parabolas, ellipses, or higher-order curves) that control the dynamic parameters of follower motion. These parameterized curves are designed to maintain acceptable acceleration and jerk levels even at high rotational speeds, enabling increased productivity while preserving component integrity through reduced dynamic loading.
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
This design allows the torque limiter to operate continuously at high speeds without damage or changes in torque levels, reducing noise and wear, and ensuring extended service life even in challenging environments.
Implementation Method 1
the curve of the engagement surface 16 which the follower elements traverse when engaged and disengaged thereby minimizing dynamic loading of the follower elements induced thereform
Implementation Method 2
which does not create large dynamic loads or stresses in the components which exceed the elastic limit of the elements even when operated at high speeds of 1800 rpm or greater such as to minimize shocks and resultant wear and noise during operation
Data Source
AI summary
A resettable torque limiter for installation between two rotary members, which can smoothly disengage upon application of predetermined torque acting between the members and smoothly reset upon decline of applied torque below the predetermined level. An undulating engagement surface formed on one member according to a function preferably an eighth power polynomial is engaged by a plurality of engagement elements on the other member which smoothly ride over lobes formed on the engagement surface when the torque limit is exceeded without causing any discontinuities in acceleration or jerk when the driving connection between the rotary members is interrupted until the applied torque declines below the preset limit.