Clutch System

dushanf · April 18, 2015

Hi everyone,

Hope you all are keeping well..

This is not a mechanical problem I'm having but to seek for an answer for a question I have regarding auto engineering for quite sometime.

I know how a clutch system work, its components and principals. But I have this question why does not it slip at high loads, when climbing a hill or at rapid accelerations if it is locked with friction only.

For example we have seen how a lorry struggles carrying a heavy load when climbing a hill, so I'm sure there is lot of torque passed through the drive train but how come it does not beak loose in the clutch where it is just attached with friction?

Thank you,

Best Regards,

Dush

Davy · April 18, 2015

Good question.

In one word, the answer to your question is: Friction.

The friction material used to manufacture a clutch has a very high coefficient of friction, which doesn't allow it to slip that easily. The pressure plate secures the clutch against the flywheel and itself, so that the clutch does not slip. As long as the surface of the clutch has enough meat (to grab on to both the pressure plate and the flywheel), and as long as the pressure plate is applying the required amount of force on the clutch, it will not slip.

Rumesh88 · April 18, 2015

In fact clutches do slip! That is, if you are in the wrong gear for a given load. Basically if you are in a higher gear than that is required to take up the load, the clutch begins to slip and give out a burning smell. In certain instances like clutch balancing you deliberately allow the clutch to slip so that the vehicle remain stationary.

The Don · April 20, 2015

On 4/18/2015 at 8:23 AM, Rumesh88 said:
In fact clutches do slip! That is, if you are in the wrong gear for a given load. Basically if you are in a higher gear than that is required to take up the load, the clutch begins to slip and give out a burning smell. In certain instances like clutch balancing you deliberately allow the clutch to slip so that the vehicle remain stationary.

Excellent simple explanation

aamarakoon · April 21, 2015

It happens alright. When I was small we lived on a top of a hill. A container truck coming to a factory close by regularly got stuck on the uphill gradient. The engine never stalled, but it just couldn't pull through due to a slipping clutch. A fork lift was used every time to push it from behind.

dushanf · April 22, 2015

Thank you very much Davy, Rumesh88, The Don and aamarakoon. And aamarakoon thanks a lot for the concrete example, I needed something like that to hear to clear my mind. Can have a good sleep with a clear mind now.