Compact Disc Spring Torque Limiter Design
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Solution Overview
Problem
Torque limiting clutches used in hollow shaft motors face challenges in size reduction, accessibility, and serviceability, particularly due to reliance on spring cup assemblies and complexity in maintenance, which hinders compactness and ease of operation.
Innovation Solution
A compact disc spring torque limiting clutch design that employs a machined disc spring, such as a Belleville spring, to set the breakaway torque without relying on spring cup assemblies, allowing for a minimized axial length and integration of shields, sensors, and a removable output hub subassembly for easy servicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If spring cup assemblies are used to set breakaway torque, then the clutch can maintain operational capabilities, but the axial length and overall size increase
Solution Approach 1:
The patent extracts and eliminates the spring cup assemblies from the clutch design, replacing them with a more compact torque setting mechanism that uses a spring directly integrated into the clutch structure, thereby reducing axial length while maintaining torque limiting functionality
Solution Approach 2:
The patent transitions from using spring cup assemblies (which extend axially) to a different dimensional arrangement where the spring is integrated within the clutch body, changing the spatial configuration to reduce axial length while preserving the torque setting capability
2Ease of repair
If the clutch is positioned for easy accessibility, then serviceability improves, but the overall layout and space requirements increase
Solution Approach 1:
The patent segments the clutch into modular components that can be easily accessed and serviced independently, allowing maintenance activities to be performed on a compact unit without requiring extensive disassembly or large installation space
3Reliability
If the friction area is shielded from contaminants, then reliability improves, but the device complexity increases
Solution Approach 1:
The patent merges the shielding function with existing clutch components, integrating contaminant protection into the clutch housing and friction element structure rather than adding separate shielding elements, thereby protecting the friction area while minimizing additional complexity
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 achieves a significant reduction in size, enhances serviceability, and maintains operational capabilities while protecting the friction area from contaminants, facilitating easy maintenance and reducing downtime.
Implementation Method 1
a machined disc spring, such as a Belleville spring, applies force on a end plate to set a characteristic breakaway torque for the clutch assembly
Implementation Method 2
a torque limiting clutch has a characteristic breakaway torque allowing slippage between input and output shafts or mechanisms when the torque on the shafts exceeds the characteristic breakaway torque of the clutch
Data Source
AI summary
A compact disc spring torque limiting clutch has an input hub and an output hub having a friction pack that is removable from the input hub as an entire unit to facilitate servicing and repair. The force actuator of the torque limiting clutch is a Belleville spring or machined disc spring that is operatively interposed between the input hub and the friction pack. The deflection of the Belleville spring during the useful life of the friction pack is within the flat portion of the force vs. deflection curve and establishes a characteristic breakaway torque for the torque limiting clutch. The use of a Belleville spring significantly reduces the axial dimension of the torque limiting clutch, adapting it for use in applications where space is at a premium.