Clutch

By Unknown - March 17, 2013

Clutch

The clutch is housed between the engine and transmission where it provides a mechanical coupling between the flywheel and the transmission input shaft.The main purpose of the clutch is to disengage the engine from the drive line while changing gears or starting from rest,however, there are other requirements too.

REQUIREMENTS:

(1) Pick up load smoothly.

(2) Have a driven disc of low moment

of inertia for quick shifting.

(3) Damp vibrations of crankshaft.

($) Require little pressure to operate.

(5) Be easy to access.

(6) Be cheap to manufacture.

Now, Mechanical clutches fall in two main categories positive engagement and progressive engagement.

The former is either positively disengaged, so that no torque can be transmitted from the driving to the driven shaft, or positively engaged, in which case the shafts rotate together, connected by some mechanical devices such as splines, keys or dogs. In contrast, the progressive type is gradually engaged, so that the speed of the driving shaft falls while, simultaneously, that of the driven shaft rises from its initial stationary state until both are rotating at equal speeds.Positive engagement clutches are unsuitable for connecting the engine to the gearbox, though they are used inside gearboxes.For road vehicles, a progressive engagement clutch of the friction type is interposed between the engine and the gearbox.

Basic Principle of Friction Type Clutch:

To understand the working principle, let us take two discs with rough contact surfaces.One is being rotated by a powerdrill (corresponding to flywheel being driven by engine). Now, when the second one is made to contact the first one it rotates, but at a slower speed, but when the second one is pressed to the first plate it rotates almost at the same speed.This is basically how the clutch works.

Multi-coil spring single plate clutch

The clutch comprises of two discs, one is clutch plate and the other is pressure plate.The clutch plate is a thin mid plate interposed between the flywheel and the pressure plate, with linings of high coefficient of friction impregnated on it.The purpose of the pressure plate is to press the clutch plate to the flywheel with the help of spring action, and also to release the pressure by pressing the pedal so as to disengage it.

Now clutches can be of various types-coil spring clutch, diaphragm clutch, single plate clutch, multi plate clutch, centrifugal clutch, cone clutch and many more.