All About Clutches

[Neil.Bhujbal]

How Centrifugal Clutch Works - In simple words & as the name says it works on the centrifugal force theory which is "outward force away from the center of rotation".

So as you see in the above pic the (1)HUB is connected to the crankshaft of the engine.As you start the engine it starts rotating.

Now when you accelerate (raise the engine RPM) the "centrifugal force acts" i.e the (1)HUB rotates & forces the (2)FLY WEIGHT to go and attach to the (6)CLUTCH DRUM.

The (2)FLY WEIGHT cause the (6)CLUTCH DRUM to rotate which is connected to the rear wheel by belt in mopeds & i guess by chain in clutch less bikes.

Now when you leave the accelerator or brake & at certain RPM limit the (4)TENSION SPRINGS have force greater than the centrifugal force which bring back the (2)FLY WEIGHT to its original position & keep on rotating in that original position until the RPM raises again.

 

[RSM]

Neil, good article, and complex too.
Do we have any other type of clutch than centrifugal?

 

[Neil.Bhujbal]

Thanks. Yes there are more types of clutch.

The centrifugal is mostly used on Mopeds.

 

[Renegade]

Thanks. Yes there are more types of clutch.

The centrifugal is mostly used on Mopeds.

Can you enlighten us on the clutchs used in cars.

 

[raj_5004]

there are basically two types of clutches:
1) friction clutches- its works on the principle of friction.
2) fluid flywheel- it is used in auto transmissions

in friction clutches, there are many types:
1) cone clutch- not usually used.
2) single plate clutch- used in cars
3) multiplate clutch- used in bikes, racing cars & heavy vehicles
4) semi-centrifugal clutch
5) centrifugal clutch

there is a diaphragm spring type clutch where instead of springs, diaphragm plates are used.

all the above mentioned are dry clutches.

there are even wet clutches which are mostly used in trucks.

 

[cooldhaya]

Hey nice explanation Rajeev and Neil!!

 

[Neil.Bhujbal]

Single Plate Clutch

Now the diagram surely looks complex but the working is pretty simple & clean. Just depends on how well you understand.

* The flywheel A is bolted to engine directly.
* The plate C is fixed to a boss H which is free to slide axially(left-right) along the driven shaft D to which it is splined.It therefore rotates with shaft D.
* Two rings G of special friction material are riveted or bonded to A and E or alternatively to plate C.
* The presser plate E is bushed internally so that it revolves freely on the driven shaft D. It is integral with the withdrawl sleeve F.
* A number of springs are arranged around the clutch ( Shown as S) so as to press the two friction surfaces together.

The Clutch operates by moving the withdrawl sleeve F to the right. This compresses the Springs S are removes the pressure between the friction surfaces. Hence it is possible to start of stop the driven shaft at will.

 

[RSM]

I am still feeling its complex

 

[Arun]

A gif image will do justice Neil. It is confusing me!

 

[Neil.Bhujbal]

I am still feeling its complex

A gif image will do justice Neil. It is confusing me!

You see the " H " ? That H part slides to the RIGHT SIDE on the shaft D when you press the clutch. Now when this H part slides to the right the C (clutch plate) no longer is attached to the flywheel A.(this is when the clutch is dis engaged & you change gears)

Now when you leave the clutch the H part slides to the LEFT SIDE again(to its original place).Now as it slides to LEFT the C (clutch plate) gets engaged with the flywheel A again.(this is when the clutch is engaged & you speed up)

 

[ilango[speed thirst]]

Hows the power transmitted in the 2nd diagram.

from figure , s need to be pressurized to transfer the power. Did i get it correct?

 

[raj_5004]

when you depress (disengage) the clutch pedal (that means engaging the clutch), the pressure plate (E) is pressed towards the friction plate which in turn is pressed towards (A), because of the spring force(S).

because of the friction, F starts moving along with A in the same speed.

now when you press the clutch pedal (that means disengaging the clutch), F is pulled towards right. this means that there is no contact between E & A, so the clutch is disengaged.

 

[Renegade]

Here is a a flash animation which will help you to understand the working of the Single Plate Clutch(with diaphragm)

Single Plate Clutch

 

[Neil.Bhujbal]

Man ! Why dint you post that earlier ?

 

[CITY BOY]

Clutch plates of honda city

Sir
how does we get to know that our clutch plates requires change,