Overload Clutch Ribbed Disc Encapsulation
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Solution Overview
Problem
Existing overload clutches suddenly open during load threshold exceedance and re-engage uncontrolled, lacking reproducibility and stability.
Innovation Solution
A two-component plastics injection-molded clutch with a ribbed disc and a viscoplastic encompassing ring, where the ribbed disc is encapsulated on three sides by the ring, enabling a transition from adhesive to sliding friction and back to adhesive engagement, maintaining torque transmission without loss, with the rib geometry and material pairing influencing the reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive engagement is used for torque transmission, then torque can be transmitted without loss, but the clutch opens suddenly and re-engages uncontrolled during overload
Solution Approach 1:
The clutch transitions from static adhesive engagement to dynamic sliding friction during overload, then returns to static engagement when load decreases. This dynamic transition allows controlled response to overload conditions while maintaining stability during normal operation.
Solution Approach 2:
The friction characteristics change based on load parameters - under normal load the clutch maintains adhesive engagement with high friction, while under overload the friction transitions to sliding mode with lower friction, enabling controlled disengagement and re-engagement.
2Reliability
If the clutch fully opens during overload, then torque transmission is interrupted, but the clutch cannot maintain stable engagement and re-engages uncontrolled
Solution Approach 1:
The clutch provides feedback through friction transition - when overload occurs, the increased friction heat causes the plastic ring to expand, transitioning from adhesive to sliding friction and reducing torque transmission. When load decreases, cooling causes shrinkage and re-engagement, creating a self-regulating feedback mechanism.
Solution Approach 2:
The plastic ring expands due to friction heat generated during overload, causing dimensional changes that reduce the interference fit and transition the clutch from adhesive to sliding friction, thereby interrupting torque transmission in a controlled manner.
3Reliability
If adhesive engagement is maintained during overload, then torque transmission continues, but the clutch cannot provide overload protection
Solution Approach 1:
The friction heat generated during overload, which is normally a harmful effect, is utilized beneficially to cause thermal expansion of the plastic ring. This expansion automatically reduces the interference fit and transitions the clutch to sliding friction, providing overload protection without external control systems.
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 clutch provides a reproducible and stable reaction to overload, maintaining torque transmission without loss, and can be standardized for low torques while suitable for high torques in restricted spaces, with the ability to cascade for higher loads.
Implementation Method 1
the encompassing ring as the second of the clutch partners exhibits pronounced temperature-dependent shrinkage behaviour, and therefore, during the course of the cooling, presses the encompassing ring with yoke and limbs against the ribbed disc
Implementation Method 2
the ribbed disc lies, with an encircling ring-shaped region within its outer circumference, in non-positively locking fashion against the interior of the U-shaped yoke
Implementation Method 3
a transition from the adhesive (static friction) engagement to sliding friction between the two clutch partners occurs in a ring-shaped region within the outer periphery of the ribbed disc, and thus the free end regions of the U limbs of the encompassing ring are spread open in positively locking fashion
Implementation Method 4
the clutch pairing, in the absence of mutual contact between the clutch partners, has cooled again and the ring, which shrinks as a result of cooling, thus enters into adhesive (static friction) engagement with the hub again
Data Source
AI summary
A clutch which reacts to torque overload has a ribbed disc which is produced by plastics injection moulding and which is, along its inner or outer periphery, encapsulated in encircling fashion and on both axial side surfaces by an encompassing ring. Said encompassing ring, owing to shrinkage as a result of cooling, enters into static friction engagement with the ribbed disc, and furthermore engages, by means of bevelled flanks, with ribs running radially on at least one of the side surfaces of the ribbed disc.