On Fri, 28 May 1999 14:10:19 -0500, Stinocher, Bryan D. wrote:
>
>Listers,
>
>I am basically an ignorant cuss when it comes to cars. I can figure
a lot of
>things out (hence, my attempt to restore my car), but for the life of
me I
>can't figure out how the clutch works. I rebuilt everything (yes, it is
in
>correctly), but how does it work?
>
>You press on the clutch pedal. It is hydraulically activated at the
clutch
>master cylinder and pushes on the clutch shaft. This moves the
fork, which
>pushes the TOB into the clutch housing (for lack of a better term)
springs.
>What happens from there? I am assuming that somehow the clutch
disc is then
>engaged/disengaged from the flywheel, and this allows you to shift.
Couple things you need to realize.
1. It appears the transmission input is connected to the flywheel,
but it is actually free to rotate in a bushing.
2. The clutch has 3 parts: flywheel, disc, and pressure plate.
The pressure plate is bolted to the flywheel, so they are both
turning at engine RPM all the time. The disc is sandwiched
in between, and also rides in splines on the transmission input,
so the clutch disc is always turning at transmission rpm.
3. The pressure plate has a fixed part (the outside) and an
inner part which can move back (towards transmission) and
forward (towards flywheel).
4.In the normal condition strong springs force this part forward
against the flywheel. The disc is then firmly held between the
pressure plate and flywheel, so that they all turn as a unit (and
hence the flywheel/ crankshaft and transmission input shaft will
turn at the same rpm.
5. The TOB, when moved forward (towards the pressure plate
moving part) contacts the pressure plate. As that happens,
the TOB will come up to the same rpm as the pressure plate.
The part the TOB contacts is actually a set of "levers" that
compress the springs in the pressure plate. As they compress, the
movable portion is no longer held tight against the flywheel (and
disc) and as a result, the disc will lose friction and start to slip
relative to the flywheel / pressure plate (remember
these are bolted together). This allows the transmission input
to slow (or speed up) as required to match the gear ratio and
output shaft speed.
If this makes any sense, then the key is the clutch disk always
turns with the transmission, and the pressure plate always
turns with the engine. The spring force and the disc material
together create the friction required to make them turn without
slip.
scott s.
.
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