by Karim Nice and Charles W. Bryant
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Please copy/paste the following text to properly cite this HowStuffWorks article:
Nice, Karim, and Charles W. Bryant. "How Clutches Work." 16 October 2007. HowStuffWorks.com. 21 August 2009.
[pic]Inside this Article
1. Introduction to How Clutches Work
2. Fly Wheels, Clutch Plates and Friction
3. Common Problems
4. Types of Clutches
5. Lots More Information
6. See all Transmissions & Drivetrain articles
How Clutches Work
• More Auto Videos »
If you drive a manual transmission car, you may be surprised to find out that it has more than one clutch. And it turns out that folks with automatic transmission cars have clutches, too. In fact, there are clutches in many things you probably see or use every day: Many cordless drills have a clutch, chain saws have a centrifugal clutch and even some yo-yos have a clutch.
Transmission Image Gallery
|[pic] | |Diagram of car showing clutch location. See more transmission images. |
In this article, you'll learn why you need a clutch, how the clutch in your car works and find out some interesting, and perhaps surprising, places where clutches can be found. | Ads by Google |
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Clutches are useful in devices that have two rotating shafts. In these devices, one of the shafts is typically driven by a motor or pulley, and the other shaft drives another device. In a drill, for instance, one shaft is driven by a motor and the other drives a drill chuck. The clutch connects the two shafts so that they can either be locked together and spin at the same speed, or be decoupled and spin at different speeds. In a car, you need a clutch because the engine spins all the time, but the car's wheels do not. In order for a car to stop without killing the engine, the wheels need to be disconnected from the engine somehow. The clutch allows us to smoothly engage a spinning engine to a non-spinning transmission by controlling the slippage between them. To understand how a clutch works, it helps to know a little bit about friction, which is a measure of how hard it is to slide one object over another. Friction is caused by the peaks and valleys that are part of every surface -- even very smooth surfaces still have microscopic peaks and valleys. The larger these peaks and valleys are, the harder it is to slide the object. You can learn more about friction in How Brakes Work. A clutch works because of friction between a clutch plate and a flywheel. We'll look at how these parts work together in the next section.
Fly Wheels, Clutch Plates and Friction
In a car's clutch, a flywheel connects to the engine, and a clutch plate connects to the transmission. You can see what this looks like in the figure below. [pic][pic]
Exploded view of a clutch
When your foot is off the pedal, the springs push the pressure plate against the clutch disc, which in turn presses against the flywheel....