The document discusses various machine elements and their functions. It defines machine elements as individual components or groups of components that perform specific functions in machines, such as holding components together, transmitting power, or providing support. It then describes different types of machine elements categorized by their functions. The rest of the document provides details on specific machine elements, including shafts, axles, spindles, clutches, brakes, belts, gears, and their characteristics and applications.

1. Prof. A.B. Humbe
HOD, Applied science Department
ICEEM Aurangabad

2.  Machine element is an individual component or a group of
components of a machine which performs a specific function.
 Its function may be of holding the components together, to
transmit power or to give supports.
 Depending upon these functions only, the machine
elements are following types.
1) Machine elements used for holding the components.
2) Machine elements used for transmitting the power.
3) Machine elements used for support of other components.

3.  Shaft:- It is rotating, circular cross section member used to transmit
the power from one point to another point. The shaft is rotated by
the application of tangential force applied by fitting components
like belt, pulleys, gears etc.
 Types of shafts :
1.Transmission shaft : It is used to transmit power between power
source and machine absorbing power. e.g. Line shaft , counter
shafts.
2.Machine shaft : It is integral part of the machine itself. e.g. Crank
shaft , camshaft in automobile , main shaft of turbine.
 Axle :- An axle is member which is used to support rotating
wheels. It carries load.
 Spindle:-A spindle is short shaft used to give motion to a cutting
tool or work piece on a machine tool.

4. Sr .No Shaft Axle
1 Rotating member Non-Rotating member
2 Used to transmit the torque and
support the
transmission elements, like: gears,
pulleys
Only used to support the
transmission
elements, like: wheels, pulleys etc
3 It is subject to torque, bending
moment and axial force
It is subjected to bending moment
and
axial force
4 Example- line shaft, counter shaft,
spindle, crankshaft
Example:- front axle of car, wheel
axle of
motorcycle etc.

5.  It is mechanical device which is used to connect or
disconnect the driving shafts from the driven at the will of
operator.
 It is mounted between driving shaft. The flow of
mechanical power from prime mover to the driven machine
is controlled by means of clutch.
 In automobiles in order to change the gears or to
temporarily stop the vehicle, the requirement is that the
driven shaft should stop but the engine should continue to
run. This is achieved by means of clutch mounted between
engine and the gear box which is operated by lever.

6. 1. Positive
2. Friction
a. Plate
i) Single Plate
ii) Multi Plate
b. Cone
c. Centrifugal

8. • It consist of two flanges. One is connected rigidly to a driving
shaft with the help of key. The other flange is free to move along
the driven shaft.
• A spring is used to provide an actuating force. The sliding plate
is forced to remain in contact with fixed plate with spring force
and power transmitted from driving shaft to driven shaft.
• Driving shaft flange is lined with friction material such as ferredo
( friction plate)
• It makes perfect contact between two flanges because of spring
force. No slipping occurs because of friction plate.
• Power is transmitted smoothly when driven shaft is to be
disconnected the force is applied by the operator against the
spring force and the flange on the driven shaft is moved along
the axis away from the friction plate.
• Used in automobiles

10. • It is used to transmit large torque.
• The working principle is same as single plate clutch
but the contact area is increased by providing more
number of plates.
• It consist of outside plate connected to casing of the
flange keyed to the driving shaft.
• The inside plates are fastened to driven shaft through
splines can have axial motion.
• The axial force which is required to hold the disk
together is provided by means of spring.
• When driving shaft rotates resulting in rotation of
discs and through inside plates driven shaft transmit
the power due to friction.
• Multi plate clutch are usually oil cooled.
• Use motor cycle scooters also in machine tools.

11.  It is the mechanical device used to slow down or completely
stop the motion of moving system such as machine, vehicle or
rotating drum, by applying an artificial frictional resistance .
It is also used to hold the system under load at rest.
 In the process of performing this function , the brake absorbs
the energy given by the moving system.
 The energy absorbed by the brake can either kinetic energy or
potential energy or both.
 The energy absorbed by the brake is converted into heat and
dissipated to the surrounding air .

12. On configuration On mode of actuation
 Block or shoe brake
 Drum and shoe brake
 Disk brake
 Band brake
 Band and block brake
 Mechanical brakes
 Pneumatic brakes
 Hydraulic brakes
 Electrical brakes
 Automatic brakes.

13.  It consists of simple block or shoe
which is pressed against rotating
drum.
 The block which is rigidly
attached to the lever or in some
applications pivoted to the lever is
lined with friction material like
asbestos, leather etc.
 The actuating force is applied at
the end of lever.
 Applications:- In trains

14.  It consists of two blocks or two shoes pressed against a rotating drum by
means of levers.
 The blocks or shoes which are pivoted to the levers, are lined with friction
material like asbestos ,cork etc.
 The actuating force is applied at the end of actuating lever.
 The friction between the friction lining on the blocks and the brake drum
causes the retardation of the drum.
 Applications :- Cranes, Trains

15.  It consists of two shoes. The outer surface of shoes are lined with some
friction material.
 Each shoe is pivoted at one end about hinge-pin subjected to actuating
force at the other end.
 The actuating force on both shoes is applied by a hydraulic cylinder or a
cam mechanism.
 When force is applied it causes the brake drum either to retard or stop
completely.
 When actuating force is release retracting spring return the brake shoes.
 Applications:- Trucks, buses, cars, motorcycles.

16.  It consists of a flexible steel band lined with the friction material, which
embraces a part of the circumference of brake drum.
 The ends of band are joined to the lever which is pivoted at point o.
 In order to apply the brake, the band is tightened around the brake drum by
applying force at the end of the lever.
 The frictional force between the band and the brake drum provides
necessary braking force.
 This is not commonly used as shoe brakes.
 Applications:- Material handling equipment.

17.  It consists of number of wooden blocks fixed insight the steel band.
 A steel band is fixed with wooden blocks embraces the part of
circumference of the brake drum.
 The end of steel band are attached to lever which is pivoted at point o.
 When the actuating force is applied at the end of lever, the wooden blocks
are pressed against the brake drum.
 The frictional force between wooden blocks and drum provides the braking
force.
 It is not commonly used as shoe brake.
 Application:- Material handling equipment's.

18.  The belts or ropes are used to
transmit power from one shaft to
another by means of pulleys which
rotate at the same speed or at
different speeds.
 The amount of power transmitted
depends upon the following factors:
1. The velocity of the belt.
2. The tension under which the belt is
placed on the pulley.
3. The arc of contact between the belt
and
the smaller pulley
4. The condition under which the belt is
used.
5. The material of the belt used.
Selection of the Belt Drive:
1. Speed of the driving and driven
shafts.
2. Speed reduction ratio
3. Power to be transmitted
4. Centre distance between the
shafts.
5. Positive drive requirements.
6. Shaft layout.
7. Space available.
8. Service conditions.

19.  Open Belt Drive :
It is used, when shafts are
arranged parallel and rotating
in the same direction, In this
case, the driver A pulls the
belt from one side (i.e. lower
side) and delivers it to the
other side (j,e. upper side).
Thus the tension in the lower
side belt will be more than
that in the upper side belt.
Hence lower side belt is
known as tight side, whereas
the upper belt is known as
slack side,

20.  Cross Belt Drive :
This belt drive is used
when shaft are arranged
parallel and rotating in
the opposite direction. A
crossed belt drive can
transmit more power than
open belt drive, as the
angle of wrap is more.
However, the belt has to
bend in two different
planes and it wears out
more.

21.  Quarter Turn Belt Drive :
The quarter turn drive always
known as right angle belt
drive, is used with shafts
arranged at right angles and
rotating in one definite
direction. In order to prevent
the belt from leaving the
pulley, the width of the face
of the pulley should be
greater or equal to 1.4 b,
where b- is the width of the
belt. when the reversible
motion is desired, then a
quarter turn belt drive with
guide pulley.

22.  Belt Drive with idler Pulleys :
A belt drive with an idler pulley,
used with shafts arrangement
parallel and when an open belt
drive can not be used due to
small angle of contact on the
smaller pulley. This type of
drive is provided to obtain in
high velocity ratio and when the
required belt tension cannot be
obtained by other means. When
it is desired to transmit motion
from one shaft to several shafts,
all arranged in parallel, a belt
drive with many ideal pulleys
can be employed. In conveyer
system to avoid slackness of the
belt, idler pulleys are used.

23.  Compound Belt
Drive :
It is used to transmit
power from one
shaft to another
through a number
of pulleys.

24.  Stepped or Cone
Pulley Drive :
A stepped or cone pulley
drive, used for
changing the speed of
the driven shaft while
the main or driving
shaft runs at constant
speed. This is
accomplished by
shifting the belt from
one part of the steps to
the another.

25.  In belt drives, slipping of belt may occur.
 In order avoid slipping, steel chains are
used,
 The chains are made up of rigid links
which are hinged together in order to avoid
the necessary flexibility for warping
around the driving and driven wheels.
 The wheels have projecting teeth and fit
into the corresponding recesses, in the
links of The chain.
 The wheels and the chain are constrained
to move together without slipping and
ensures perfect velocity ratio.
 The toothed wheel are known as sprocket
wheels or simply sprockets.
 These wheels resemble to spur gears

27.  There are many different types of gear are used in various engineering
applications. Some of them most commonly used are as shown below
1. Spur gears :- If teeth of the gear wheels are parallel to the axis of wheel .
The gears are called spur gears. Teeth of the spur gears are cut on the
circumference of the cylindrical discs. Spur gears can transmit higher
power because of the contact between the mating gears is along a line.
 Use :- Spur gears are used for transmitting power between two shafts
when the axis of the driving and driven shafts are parallel and co – planer.
They commonly used in machine tools and automobile gear boxes.

28. 2.Helical gears :- Helical gears are similar
to the spur gears. But the teeth are cut in
the form of the helix around the gear .
Their teeth are not parallel to the shaft
axis. Two moving helical gears have
identical helix angle but opposite hand .
The helical gears run more smoothly and
more quietly at high speeds and
curvilinear contact of gear teeth giving
gradual engagement.
 The main disadvantage of helical gears is
that it produces end thrusts on the
driving and driven shafts. But when
double helical gears or Herringbone
gears are used to connect parallel shafts,
produces equal and opposite thrust on
each wheel and gets balanced and do not
transmit axial thrusts to the shafts,
 Uses :- Helical gears are used for
transmitting power between two parallel ,
non parallel , non –intersecting shafts.
Helical gears are used where smooth and
quit running at high speeds is required.
Generally , helical gears are used in
automobile power transmission.

29. 3.Spiral gear :- The teeth of spiral gears are same as
helical gears and it cut along helical path. In spiral gear ,
there is a point contact while curvilinear contact in case
0f helical gear drive. Because of the point contact in the
spiral gears are more suitable for transmitting less power.
 Use:- Spiral gears are used to transmit power between
two non – parallel , nonintersecting shafts.

30. 4.Bevel gears :- Teeth of the bevel gears are cut on conical
surfaces . Bevel gear teeth are varying in cross section
along the tooth width. The axis of two moving gears are
inclined in the bevel gear. In most of cases , two bevel
gears have their axes at right angle and are of equal sizes,
called miter gears.
 Use :- Bevel gears are used for transmitting power
between two shafts , when the axis of the two shafts are
inclined and intersect each other. Bevel gears are widely
used in automobiles.

31. 5.Worm and worm wheel :-A worm gear drive consists of worm
and worm wheel. A worm has one or more number of helical
threads of trapezoidal shape cot on it. A worm wheel is a wheel
with the tooth profile consists of small segments of helix which
engages with the worm.
 Uses :-Worm gears are used for transmitting power between two
shafts having their axis at right angles and non –co-planer.
Worm gears are suitable for transmission of power when a high
velocity ratio is required. They are mostly used in machine tools
like lathe . Milling , drilling machine etc. To get large speed
reduction.

32. 6.Rack and pinion :- Rack is a rectangular bar consist of a
series of straight teeth cut on it. Theoretically , rack is a
spur gear of infinite diameter . The rack is mesh with
another small gear known as pinion.
 Use:- The rack and pinion drive is used to convert rotary
motion into linear motion . Rack and pinion arrangement ,
generally used in machine tools. Such as lathe , drilling ,
planning machines. It also used in measuring instruments.

33.  Pitch circle :- It is an imaginary circle which produces by pure rolling action
would give the same motion as the actual gear.
 Pitch circle diameter :- It is the diameter of the pitch circle. The size of gear
is usually specified by the pitch circle diameter.
 Pitch Point:- It is common point of contact between two pitch circle

34.  Pressure angle or angle of obliquity :- It is an angle between the
common normal to the point of contact of two mating gear teeth and the
common tangent at common point between two pitch circles.
 Circular pitch :- It is the distance measured on the circumference of the
pitch circle from a point of one tooth to the corresponding point on the next
tooth.
Pc=πd /T, where T =number of teeth
 Module (m) :- It is ratio of the pitch circle diameter in millimeters to
number of teeth. m = d/T
 Addendum:-It is the radial distance of a tooth from the pitch circle to the
top of tooth
 Dedendum:-It is the radial distance of the tooth from pitch circle to the
bottom of tooth
 Diametral Pitch:-It is the ratio of number of tooth to pitch circle diameter in
mm Pd=T/d

35. Thank you…