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| CLUTCH | ||
| QUESTIONS OR COMMENTS | ||
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AUTHOR: | Luke Chuang |
| E-MAIL: | lukec@mit.edu | |
| COURSE: | 2 | |
| CLASS/YEAR: | 4 | |
MAIN FUNCTIONAL REQUIREMENT: Disengage/engage power one machine element to another
DESIGN PARAMETER: Clutch
GEOMETRY/STRUCTURE:
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| Components of A Clutch |
EXPLANATION OF HOW IT WORKS/ IS USED:
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When engaged, the clutch disc (driven plate) is sandwiched between
the pressure plate (also called clutch cover) and the
flywheel.
- The pressure plate is held in contact with the friction face of the clutch disc by spring force.
- When disengaged, the pressure plate is pulled away from the clutch disc by a release bearing assembly.
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| Cross Section of Clutch |
When the clutch pedal is depressed, the flywheel, clutch disc, and pressure plate are disengaged, thus power flow is interrupted. As the clutch pedal is released, the pressure plate moves closer to the driven plate and the flywheel; clamping the plate between the pressure plate and the flywheel. If the transmission is in gear, power is transferred from the input to the output.
DOMINANT PHYSICS:
| Variable | Description | Units |
| T | Torque transferred through the clutch | Newton*meter |
| p | Pressure on the clutch disc | Newton/meter2 |
| N | Normal force on the clutch disc | Newton |
| f | Frictional force | Newton |
| m | Coefficient of friction | --- |
| r | Radius of differential element | Meter |
| Ri | Inner radius of the contact area | Meter |
| Ro | Outer radius of the contact area | Meter |
The basic clutch device uses a frictional interface. It relies on the properties of friction to fulfill the torque transmission requirement. Assuming simple friction interface and uniform pressure distribution.
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| Differential Used To Calculate Torque Capacity |
The elementary frictional force is
The elementary normal force is
The differential torque is
Integrating dT from Ri to Ro, the total torque (torque capacity) is
LIMITING PHYSICS:
The performance/use of the clutch is limited by its torque capacity.
Torque capacity depends on the coefficient of friction (between the flywheel, driven plate and the clutch cover), the actuating force, and the size of the clutch.
PLOTS/GRAPHS/TABLES:
None Submitted
WHERE TO FIND CLUTCHES:
A clutch can be found in a car between the engine and the transmission of almost any engine that needs to be disengaged while running.
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| Location Of A Clutch In An Automobile |
REFERENCES/MORE INFORMATION:
How Stuff Works by Marshall Brain http://www.howstuffworks.com/transmission.htm
Transmissions http://www.csn.ul.ie/~lavelles/trans.html
Automotive 101: Automotive Driveline Overview http://www.autoshop-online.com/auto101/drive.html
NASCAR Garage Tech: Clutch http://www.nascar.com/garage/00638018.htm
NASCAR Garage Performance: Clutch http://www.nascar.com/garage/00421508.htm
Shaver, Ray. Manual Transmission Clutch System. Society of Automotive Engineers, Inc. c1997.
Shingley, Joseph E. and Mischke, Charles R. Standard handbook of machine design. 2nd ed. McGraw-Hill, c1996.
