Torque Limiter Cam Sleeve Mechanism
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Solution Overview
Problem
Friction-style torque limiters wear down over time, reducing their ability to protect against torque overload, necessitating adjustments to maintain effectiveness.
Innovation Solution
A torque limiter design featuring a shaft sleeve with a cam surface and resisting posts, along with an adjustment mechanism using a spring and nut, allows for stable engagement and disengagement of input and output shafts based on torque levels, preventing damage from overload by sliding the cam surface relative to the resisting posts when excessive torque is applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction plates are used in a torque limiter, then torque overload protection is achieved, but the friction plates wear down over time reducing the predetermined torque overload value and requiring adjustments
Solution Approach 1:
The patent extracts the friction plates from the torque limiter system, replacing them with a shaft sleeve and cam surface mechanism. This removal of the wearing friction elements eliminates the wear problem while maintaining the torque limiting function through the cam surface geometry and spring pressure plate system.
Solution Approach 2:
The invention replaces durable but complex friction-based torque limiters with a simpler, adjustable mechanism using the shaft sleeve and cam surface. The design allows for easy adjustment of the torque threshold without replacing worn components, effectively treating the torque setting as adjustable rather than fixed.
2Reliability
If friction plates are used for torque limiting, then overload protection is provided, but frequent adjustments are needed due to wear
Solution Approach 1:
The shaft sleeve mechanism provides automatic torque limiting through its cam surface geometry and spring pressure plate system. The design self-regulates the torque threshold through the mechanical interaction of the cam surface with the pressure plate, eliminating the need for manual adjustments that would otherwise be required to compensate for wear.
3Stability of the object's composition
If a shaft sleeve with cam surface is used, then stable engagement and disengagement is achieved, but device complexity increases
Solution Approach 1:
The patent employs a cam surface with curved geometry on the shaft sleeve that provides stable engagement and disengagement through its geometric profile. The curved cam surface naturally guides the pressure plate into and out of engagement positions, providing stability without requiring additional complex control mechanisms.
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 effectively protects driving sources and loads from torque overload by dynamically adjusting to disengage the output shaft when overload is detected, maintaining protection without the need for frequent adjustments due to wear, and allows for adjustable torque ranges.
Implementation Method 1
a spring (41) placed on the input shaft (20), for pressing the shaft sleeve (50) against the output shaft (60)
Implementation Method 2
A plurality of friction plates are mounted on the transmission shaft and the output shaft... the friction plates on the transmission shaft are resisted between the friction plates on the output shaft and a pressing plate
Implementation Method 3
sliding the cam surface relative to the resisting posts when excessive torque is applied
Data Source
AI summary
A torque limiter includes an input shaft connected to a driving source, an output shaft connected to a driven load, a shaft sleeve, and an adjustment mechanism. The input shaft includes a positioning post. The output shaft includes a resisting post. The shaft sleeve includes a cam surface and a resisting surface, and defines a cam groove in a periphery. When the driven load is in a predetermined torque range, the positioning post is engaged in the cam groove, the output shaft is rotated by the input shaft and drives the driven load. When the driven load reaches overload torque amount, the cam surface moves relative to the resisting post, the cam surface is separated from the resisting post, such that the input shaft is separated from the output shaft. Thus, the output shaft and the driven load are protected from damaged by torque overload.