In this PPT Steering Brake and Suspension system are discussed.

1. UNIT-IV
STEERING, BRAKES AND
SUSPENSION SYSTEMS

2. Steering
• Steering system provide the directional
change for the movement of an automobile
and it maintain in a position as per the
driver’s decision without strain on him.
• Steering is done by moving the axes of
rotation of the front wheel with respect to the
chassis frame.

3. Requirement of steering wheel
• It multiplies the turning efforts applied on the
steering wheel by the driver.
• The shocks of the road surface absorbed by
the wheels should not be transmitted to the
driver’s hands.
• This system should be light and stable.
• It must easily be operated with less
maintiance.

4. Function of steering wheel
• It provides wheels swinging to the left or right.
• It provides vehicle turning as per the will of
the driver.
• It provides the directional stability.
• It helps to control the wear and tear of the
tyres.

5. LAYOUT OF STEERING SYSTEM

6. Steering Components
• The following are the main components of
system.
1. Steering wheel.
2. Steering column.
3. Steering Gear.
4. Drop arm.
5. Ball joints.

7. Steering Wheel
• It is the control wheel to steer a vehicle by the
driver. It contains traffic indicator switch light
switch, wiper switch.
Steering Linkage-
The Steering wheels are turned by the steering
linkage. The steering linkage consists of pitman
arm, ball joint, drag link, steering arm, spindle,
tie rod and king pin assembly.

8. Drag link
• It is connected between pitman arm and
steering arm. It is the single piece forged
component having a ball joint socket formed
at the end in some other cases.

9. Steering arm
• It is also a forged component which is
connected to the steering knuckle. During
turning, the drag link force is converted into
turning moment about the left of king pin.

10. Arrangement of Steering Mechanism

11. Principle of Steering arm
• The steering system has a worm drive in the
steering gear box. The driving worm is bolted
to steering tube end. A cross shaft is rotated
by the driven gear at right angle to steering
tube.
• Both steering wheel and steering tube are
rotated clockwise by the rotating the roller
shaft through the steering gear.

12. Principle of steering arm
• The right steering arm is pulled by the right tie
rod to turn the right steering arm thus it
receives a push of drag link.
• The left steering arm is pushed by the left tie
rod for turning the left steering knuckle and
wheel to the right.

13. STEERING GEOMETRY
• Castor
• Camber
• Kingpin inclination
• Toe-in
• Toe-out

14. Camber
• When the front wheel of the vehicle is viewed,
the angle between centre line of the tyre and
vertical line is called camber.
• The camber is named as wheel rake. When
the wheels are tilted inwards at the top, its
negative. It is positive when it tilts outwards
at the top.

15. CAMBER
The camber should not exceed to 2 degree

16. Effects of wheel camber
• Bending stresses in the kingpin and stub axle
are reduced.
• Steering effort is drastically reduced.
• Shock load are not permitted to transmit to
the steering wheel at high speed.
• It imparts the directional stability.

17. Caster
• Tilting the kingpin axis either forward or
backward from the vertical line is known as
castor.
• The angle between the vertical line and
kingpin centerline in the plane of the wheel
when it is viewed from the side is known as
castor angle.

18. CASTER
Castor angle ranges from 2 to 7 degree in modern vehicles

19. Effects of castor angle
• The positive castor gives the directional
stability.
• The excessive positive castor tends the vehicle
rolling out. Similarly the excessive negative
castor makes the wheel to toe out.
• If castor angle on both wheels is same, both
wheels will be equally balanced. If it is greater
on one side, wheels are pulled towards the
wheel having lesser castor angle.

20. KINGPIN INCLINATION
• The angle between vertical line and centre of
the kingpin when viewing from the front of
the vehicle. It varies from 3.5 to 7.5 degrees
Effects of King Pin
1. Both King pin inclination castor give
directional stability.
2. Particularly steering efforts is reduced when
the vehicle is stationary.

21. Effects of King Pin
• Tyre wear also is greatly reduced.
• During Turning of the wheel, the inclination
raises the vehicle. So, the force is exerted on
wheels to straighten up automatically after
completing its turn.

22. Toe in
• Usually, front wheels are slightly turned to the
front side. It means, the distance (A) between
front ends slightly less than distance (B)
between back ends when it is viewed from top
as shown in figure.
• Then the wheels are said to be toe-out when
the distance A is greater than B as shown in
figure. The amount of toe-in does not exceeds
3mm

23. TOE-IN
The amount Toe-in does not exceed 3mm

24. Toe out

25. Effect of Toe out
• The inner front wheel turns for larger than the
outer wheel while turning in the figure.
• The wheel are made to toe out on turns due
to the difference in their turning angle thereby
avoiding tyre scrub.
• By keeping the proper relation between
steering knuckles arms, tie-rods and drop arm,
the toe-out occurs.

26. TYPES OF STEERING GEAR BOX
1. Cam and roller
2. Recirculating ball
3. Rack and pinion
4. Cam and turn lever
5. Screw and nut
6. Cam and peg
7. Worm and roller
8. Worm and sector
9. Worm and ball bearing

27. Recirculating Ball type Steering Gear
Box
• This type of steering wheels are used in
commercial vehicles.
• These balls reduce the friction and increases
the efficiency of the mechanism to 90%.
• The steel Balls are used to recirculated by the
ball guides in worm groves.
• The motion from the nut is transmitted to the
wheel sector.

28. Recirculating Ball Type Steering Gear
Box

29. Rack and Pinion type Steering Gear
Box

30. Cam and Lever type Steering Gear

31. Worm and Roller Gear

32. Steering Ratio
• Steering Ratio refers the numbers of turns the
steering wheel required to produce one turn
of the steering- gear cross shaft.
• In other words, the ratio of the output force to
the input force applied is knowns as steering
ratio.
• It is done by pitman Arm, Steering ration
ranges from 11:1 to 24:1.

33. Steering Ratio
• It is also determined by the following two
Factors
1. Steering-Linkage and
2. Gear Ratio in the steering ratio.

34. Turning Radius and Slip Angle
• The Radius of the circle on which the outside
front wheel travels when front wheels are
turned to their extreme outer position is
called turning radius.
• The radius range from 5m to 8m in passenger
cars. It is 45 feet for buses or trucks.

35. Turning Radius and Slip Angle
• The angle between wheel inclination and path
followed by the wheel is known as slip angle.
• This angle may vary from 8 to 10 for Dry and
Slippery pavement respectively.

36. Understeering and oversteering

37. Understeering
• When the Slip Angle at the front wheel are
greater than rear wheels, the radius of the
turn increases. At this condition, the vehicle
turns less than the rotation given by the
steering wheel.
• The vehicle will try to move away from its
normal direction of motion.

38. Over steering
• When the slip angle at the front wheel are less
than rear wheel, the radius of the turn
decreases. At the time, the vehicle will turn
more than the rotation given by the steering
wheel.
• Therefore the vehicle is kept at the right
path.So, the vehicle is needed a little steer
than theoretical steer.

39. Understeering and oversteering

40. Centre Point Steering
• When the kingpin and wheel centre are
parallel and 90 degree to the axle, the
arrangement causes disadvantages-
• The force acting at the kingpin for pulling the
wheel during running. These forces acting
together on the wheels will force to push
outwards or slay.

41. Centre point steering
• Large Bending stresses are imposed on the
stub axles and kingpin due to the kingpin
causing the wheel to run through the arc
about the kingpin instead of its own vertical
centerline.
• Heavy Steering owing to the distance between
kingpin and centerline of the wheel.

42. Centre point steering
• The condition of centre point steering can be
obtained by-
• Camber- This is achieved by the stub axle at
an angle which allows the wheel centre line to
meet the kingpin centre line.
• King pin inclination- The kingpin swivel axis is
inclined so that the center line of the kingpin
meets the centerline of the wheel.

43. Centre point steering
• The use of dished wheels: Wheels that are
dished towards the middle of the vehicle so
that the wheel centre line is more in line with
the kingpin centre line.

44. Cornering Force
• When the Vehicle turns, a centrifugal force is
acting on the vehicle which produces the
thrust on the vehicle. The force can be
counteracted by the side thrust of the vehicle
wheels for some angle with direction of the
motion of vehicle called slip angle.

45. Cornering Force

46. Reversible and Irreversible Steering
• Reversible Steering- When the Deflection of
the road wheels is transmitted though the
steering wheels to road surface, the system is
called reversible steering. If the every
Imperfection of road surface causes the
steering to rotate, it causes much strain on the
part of the driver to control the vehicle.

47. Reversible and Irreversible Steering
• Irreversible Steering-
If no Deflection to the steering the front
road wheels are transferred, it is said to be
Irreversible Steering. If the Steering wheel is not
returned easily, it will produce unwanted
stresses on the steering. So Some Degree of
Irreversible is also required.

48. Power Steering
• The front wheel are turned to the turned to
the right or left as per the will of the driver
through the mechanical advantage of the
steering gear and the linkage.
• There are some disadvantages in manual
steering-
1. It is bigger and heavier in engines on cars.
2. Low-pressure tires should be used in case of
cars with large steering ratio.

49. POWER STEERING

50. Neutral position

51. Turning of Vehicle

52. Front Axle
• The Major unit on front part of the motor
vehicle is front axle. It makes the weight of the
front portion of the automobile.
• It gives steering facility and absorbs shocks.
The weight of the front part of the vehicle is
transmitted to the road surface through front
wheels by the front axle of the vehicle.

53. Function of Front Axle
• It turns the front wheel Easily.
• It provides a cushioning effect though a
spring.
• It takes the weight of the front vehicle.
• It provides steering action.
• It takes the Braking system.

54. Front Axle

55. Components of Front axle
• Axle Beam- Axle Beam are made by the drop
forging of steel having 0.4% Carbon or 1-3%
Nickel Steel, the front Axle Beam is formed
into I-Section in the Centre Position.
• The ends are made into either circular or
elliptical. I-Section construction carries
bending loads caused by the load of the
vehicle and torque by braking of wheels.

56. Axle Beam

57. King Pin or Swivel Pin
• The steering Spindle and steering knuckle
assemblies are pinned at the ends of axle
beam in order to permit wheels to be turned
by the steering gear this pins is known as
kingpin or Steering Knuckle Pin.

58. Track Rod
• The Two stub axles arms of the front axle are
connected with ends of the track rod through
knuckle or ball joints known as track rod ends.
• The connection is done by screws to ensure
adjustment. In the stub axle, left hand and
right hand threads are formed at each end.

59. Types of front axle
• Live front axle
• Dead front axle

60. Different types of Front axle

61. Different Types of Front Axle
• Generally the front axle is dead axle. In Heavy
vehicle and most of cars the front axle is a live
axle.
• There are two types of front axles based on
the axle beam as follows.
1. Straight axle.
2. Double drop axle.
3. Fully drop axle.

62. Stub Axle
• The Steering Wheels have to turn the front
wheel. It is done by hinging the stub axle with
steering knuckle at the axle beam. The pin
which forms the pivot of this hinge is called
kingpin
• The front wheels are mounted on stub axle by
kingpins. The stub axles are made up of
forging of 3% nickel steel and alloy steels of
Chromium and molybdenum.

63. Types of stub axles
a). Elliot
b). Reversed elliot
c). Lamoine
d). Reversed lamoine

64. Types of front axle

65. Elliot Stub Axle
• The Elliot Stub Axle is connected to the front
axle by pacing in the yoke end with a kingpin
and a cotter is used to join these two together
shown in figure, the king pin is usually fixed in
the stub axle forging and its ends turns in the
forked of the axle beam.

66. Reversed Elliot stub axle
• In reversed Elliot type stub axle, the
arrangement is reversed. The kingpin is fixed
in the axle beam.
• Its ends turn in the forks of the steering
knuckle

67. Lamoine Stub Axle
• In lamoine type stub axle, l shaped spindle is
used instead of yoke type hinge.

68. Inverted Lamoine Stub Axle
• The construction is similar to the lamoine stub
axle but the upside of the axle is inverted so
that the wheel axle is below the axle beam.
• In modern vehicle, the front axles are straight.
The center of gravity of the vehicle decreases
to provide good stability and safety to high
speed vehicle.

69. Suspension system
• The chassis of vehicle is connected to the front
and rear wheels through the medium of
springs, shock absorbers and axles. All parts
perform the function of protecting parts from
shocks are known as suspension system.

70. Components of Suspension System
• Spring are used to neutralize the shocks from
the road surface.
• Dampers, called shock absorber, are used to
improve a riding comfort by limiting the free
oscillation of the spring.
• Stabilizer, called sway bar or anti-roll bar is to
prevent lateral swinging of the car.

71. Function or Objective of suspension
system
• To eliminate road Shock from transmission to
vehicle components.
• To obtain good road holding while driving,
cornering and braking.
• To keep the proper steering geometry.
• To obtain a particular height to body
structure.

72. Types of suspension springs
1. Steel springs
a) leaf springs
b) tapered leaf springs
c) coil springs
d) torsion bar
2. Rubber springs
a) compression springs
b) compression shear springs
c) steel reinforced springs
d) progressive springs
e) face shear spring
3. Air springs
a) bellow type springs
b) piston type springs

73. Sprung Weight and Unsprung Weight
• The Body of Vehicle is supported by springs.
The weight of the body is supported by
Springs called sprung weight.
• Wheels, axles and other parts of the
automobile which are not supported by the
spring called the unsprung weight.

74. Leaf spring suspension

76. Helper springs

77. Torsion bar

78. Bellow type air suspension

79. Piston type air suspension

80. Elongated bellows air spring

81. Types of suspension system
i) Front end suspension
a) independent front suspension
b) rigid axle front suspension
ii) Rear end suspension
a) longitudinal leaf spring rear suspension
b) transverse leaf spring rear suspension
c) coil spring rear end suspension

82. Longitudinal independent front
suspension

83. Sliding type independent suspension
system

84. Rear wheel independent suspension

85. Anti-roll bar
• Stabilizer or a sway bar is used in all
independent suspension to decrease the
tendency of the vehicle to roll or tip on either
side when making a turn known as anti-roll
bar.

86. Braking System
• The Mechanism Which is used to Slow and
stop the vehicle as braking system. It is an
important component of vehicle.
• In other Words the total system starting from
brake pedal or lever to the brake shoe is
known as braking system.

87. Principle of Braking system
• In this system, the kinetic energy is converted
into heat energy due to friction between two
mating surface of brake lining and brake drum.
Then the heat is dissipated into the
atmosphere.

88. Need for brakes
• To stop or slow the vehicle at the will of an
operator.
• To control the vehicle descending a hill.
• To keep the vehicle in desired position even at
rest.
• To park the vehicle and hold it in stationary
position without the presence of drive.

89. Drum Brake
• A brake Drum is connected to the wheel and
also plate is mounted on the axle casing.
• Two shoe shoes are connected on the back
plate.
• Friction lining called brake linings are provided
on brake shoe.
• One or two retractor springs are connected to
keep brake shoe away from the drum without
applying brakes.

90. DRUM BRAKE

91. External Drum Brake

92. Disc Brake
• A Disc Brake is a type of brake that uses
calipers to squeeze pairs of pads against a disc
in order to create friction that retards the
rotation of shaft, such as a vehicle axle, either
to reduce it rotational speed or to hold it
stationary.

93. Types of Disc brake
• Disc brake can be classified as follows-
• Fixed Caliper or swinging caliper type.
• Floating caliper type, and
• Sliding caliper type.

94. DISC BRAKES

95. Floating Caliper

96. Hydraulic Brakes
• Hydraulic Braking mainly consist of two main
braking system which are master cylinder and
wheel cylinder. The master cylinder is
attached to the cylinder by tubes on each of
four wheels.

97. Hydraulic braking System

98. MASTER CYLINDER

99. Tandem Master Cylinder

100. PNEUMATIC BRAKES

101. VACCUM SERVO BRAKE

102. ANTILOCK BRAKING SYSTEM(ABS)

103. ANTILOCK BRAKING SYSTEM(ABS)

104. ELECTRONIC BRAKE FORCE
DISTRIBUTION SYSTEM

105. TRACTION CONTROL