The document discusses clutches, bearings, and friction. It defines a clutch as a mechanical device that engages or disengages power transmission between driving and driven shafts. Clutches operate on the principle of friction and have main parts including a driving member, driven member, and operating member. Common types of clutches include single plate, multi-plate, and cone clutches. Bearings are machine elements that support moving components and allow relative motion while carrying loads. Common bearing types are ball bearings and roller bearings. The document also discusses different types of friction including rolling friction, boundary friction, and their role in mechanical systems.

1. A PRESENTATION ON CLUTCHES AND
ANTI FRICTION BEARINGS
BY
B.NAGA MOHAN

2. Definition:
A clutch a mechanical device that engages or
disengages the power transmission espicially from
driving shaft to driven shaft.
Purpose of clutch is:
1. Allow the vehicle to come to a stop while transmission
remains in gear.
2. Allow the driver to smoothly take off from a dead stop
3. Allow the driver to smoothly change gears
4. Must be able to transmit power and torque without
slipping

3. Principle:
 It operates on principle of friction.
 When two surfaces are brought in contact and are held
against each other due to friction between them ,they can
be used to transmit power.
 Then one is rotated then other also rotates.one surface is
connected to engine and other to the transmission system
of automobile
Main parts of clutch:
1.Driving member
2.Driven member
3.An operating member

5. • Single plate clutch:
• A disc clutch consists of clutch plate which is free
to slide axiallyon splines cut on driven shaft.
• A spring loaded presses the clutch plate firmly
against the flywheel when the clutch is engaged
position
• When the clutch is in disengaged
postion the spring press against a cover
attached to flywheel. Thus both flywheel and
pressure plate rotate with input shaft.
• Fig shows the pressure plate pulled back
by release levers and friction linings on
clutch plate are no longer contact with the pressure plate or flywheel.
Thus the flywheel rotates without driving clutch plate and driven shaft.

6. • Multi plate clutch:
• When a great amount of torque to
transmit instead of single plate no of
friction plates are employed.thus
Increases the no mating friction
surfaces it is called multi plate
clutch.
• These are used in heavy commer-
cial vehicles,racing cars and motor
Cycles for transmitting high torque.
• Discs plates are free to slide on spl-
ines on driven shaft and rotate with
it

7. Cone clutch:
• Here the contact surfaces
are in the form of cone.
• When the clutch is engased
the two cones are in contact
so torque is transmit from
to another shaft through fly
flywheel.In disengage position
the inner cone back through a
lever system against the
Spring force.
• Used in automobiles and other combustion engines.

8. • Centrifugal clutch:
• It is a driving member consisting of
four sliding blocks. These blocks are
Kept in position by using springs.
• As the speed of shaft increases the
centrifugal force on shoes increases.
When cf exceeds rf of springs the shoe
Moves forward and press against inside
Of rim and torque is transmitted to rim.
• when motor gains sufficient speed to take up load in an effective
manner.
• The outer surface of shoe lined with friction material.
• It is used in machines.

9. Rolling friction:
• It is the resistance to motion that tak
Es place when a surface is rolled over
Another surface.
• Due to surface contact ,the cylinder
Or ball possess weight and pressure
Deformation takes place
• The amount of deformation depends on elasticity of materials in
contact and pressure.with harder surfaces the deformation is small.it
makes two surfaces have area of contact rather point or line contact.
• Rolling friction depends on quality of surface, load ,diameter of
rolling object,surface area of body.

10. • Bearing:
• A bearing is a machine element which support another moving
element
• It permits a relative motion b/w contact surfaces of members which
carry load
• The rolling occurs between shaft and rollers .
• The balls in bearings are made up of hardened steel such as
chromium steel or chromium nickel steel.
• Ball bearing:
• It consists of number of harden-
ed balls mounted between two
harden races.
• Inner race is fitted to shaft and
the outer race is a tight fit into
bearing housing.

11. • There is no relative motion between shaft and
inner race and outer race and housing.
• Shallow grooves are present in races to hold
the balls
• A large brass cage keeps the ball at fixed distace
from one another.
• The balls and races are very hard ,distortion
is little and rolling friction is low.
• The friction of ball bearings reduced by using lubricant than dry.

12. Roller bearing:
• Here balls are replaced by hardened
cylindrical rollers.
• Fig shows the radial roller bearing .
type of bearing carry only radial loads
or loads perpindicular to shaft axis.
• A cage keeps rollers at uniform distance
apart.
 When the rollers are small and used
without cage they are known as needles.
such bearings are used to carry heavy loads.
• Roller bearings are not used for misaligh
ned shafts.

13. • Boundary friction(greasy friction):
• It is friction experienced b/w rubbing surfaces ,when the rubing
surfaces have thin layer of lubricant
• The thickness of this very thin layer is of molecular dimension.
• In this type of friction a thin layer of lubricant forms a bond b/w two
rubbing surfaces.
• The coefficient of friction is considerably reduced when compared to
surfaces unlubricated.
• The property of lubricant to form a layer of molecular thickness on a
metallic is known as oiliness.
• The boundary friction follows the solid friction.

14. Thank you