limited slip differentials are used to
overcome the drive wheel traction
difference problem
pressure ring based clutch pack lsd is
one of the most preferred lsd technology
first let's go through its
constructional features
the major difference between a standard
and limited slip differential is that in
lsd the spider gears are not directly
connected to the case
instead the spider gears sit between a
pair of pressure rings
and these pressure rings are fitted in
the slots of the case
it is clear that the side gears are also
well placed between the pressure rings
a pair of clutch packs is fitted between
the case and pressure rings
if the clutch pack assembly is well
pressed the frictional force within them
will make it move as a single solid unit
since steel plates are locked with the
case and friction discs with the side
gear in a well pressed clutch pack
motion from the case is directly passed
to the side gears
or the left and right axles will be
locked and the whole mechanism will move
as a single unit
when the vehicle is in a stalled
condition due to the traction difference
it is natural that the driver will press
the accelerator pedal
the pressure rings are in the slots of
the case so speed change in the engine
is instantly transferred to it
but since the spider gears have got an
allowance for tangential motion they
won't be able to catch up with the speed
change
this means that the shaft of the spider
gears will move as shown
relative to the pressure rings
due to the slanting shape of the cam
groove this shaft motion will push apart
the pressure rings which in turn will
push and lock the clutch packs
as a result the whole mechanism is
locked now and moves as a single solid
unit
thus an equal amount of torque will be
transferred to the right and left wheels
so the vehicle will be able to overcome
the traction difference problem
this kind of lsd is known as one-way
type because the differential locking
will happen only during the acceleration
during deceleration the shaft motion is
blocked by the flat cam surface
but by changing the design of the
pressure ring slightly even during
deceleration the clutch packs can be
activated
here the groove has a symmetrical shape
they are called as two-way type
but the two-way type is not advisable
for normal driving since during
cornering vehicles are usually
decelerated
there is also 1.5 way type of lsd
available
this is essentially a two-way type with
better locking during the acceleration
than in deceleration
that's all about the working of pressure
ring based lsd thank you