brief introduction to automotive steering system, wheel geometry etc

1. BY – VISHU SHARMA

3.  KEY INTERFACE BETWEEN
DRIVER AND VEHICLE
 SET OF MECHANISM USED TO
CONTROL THE PATH
FOLLOWED BY VEHICLE
 ALLOW DRIVER TO GUIDE
THE VEHICLE

5.  CONVERTS ROTARY
MOTION INTO ANGULAR
TURN OF WHEELS
 MULTIPLIES EFFORT OF
DRIVER
 PROVIDES DIRECTIONAL
STABILITY

6.  OPTIMIZE TIRE LIFE BY
PROPER TIRE TO ROAD
CONTACT
 HOUSES SAFETY DEVICES
LIKE AIRBAGS
 ABSORBS PART OF ROAD
SHOCKS

9.  RELATIVE NO. OF TURNS OF
STEERING WHEEL TO MOVEMENT OF
WHEELS
 SIZE OF PINION GEAR AND NUMBER
OF TEETH ON GEAR DETERMINES
STEERING RATIO
 EFFECTS RESPONSE OF VEHICLE

10.  HEAVIER
VEHICLES HAVE
HIGHER STEERING
RATIO
 MORE TURNING
OF STEERING
WHEELS
 RESULTS IN
LESSER EFFORT
 LIGHTER
VEHICLES HAVE
LOWER STEERING
RATIO
 LESS NO. OF
TURNS
 REQUIRES MORE
EFFORT TO TURN

11.  SIZE OF STEERING WHEEL
 RELTIVE SIZE OF GEARS IN
STEERING GEAR
 SIZE AND SHAPE OF STEERING
LINKAGES
 PERCENT OF VEHICLE WEIGHT
PLACED ON FRONT WHEEL
 FRONT WHEEL OR REAR WHEEL
DRIVE

13.  CASTER ANGLE
 CAMBER ANGLE
 STEERING AXIS INCLINATION
 TOE
 THRUST ANGLE
 TURNING RADIUS
 SUSPENSION HEIGHT

14. ANGLE B/W VERTICLE LINE AND
KINGPIN CENTRELINE (FROM S.V.)
FUNCTIONS
 SELF CENTRING
ACTION
 STRAIGHT LINE
STABILITY
 EXCESSIVE CASTER
MAKES STEERING
HEAVIER, LESS
RESPONSIVE AND
INCREASED EFFORT

15. INWARD OR OUTWARD TILT OF WHEEL
(FROM F.V.) FUNCTIONS
 +VE CAMER LOWER
STEERING EFFORT
 -VE CAMBER
IMPROVES GRIP
 EXCESSIVE CAMBER
CAUSES INCREASED
TIRE WEAR, REDUCES
STRAIGT LINE
ACCLERATION

16. ANGLE B/W VERTICLE LINE AND
KINGPIN CENTRELINE (FROM F.V.)
FUNCTIONS
 HELPS IN
STEERING
RETURNABILITY
AFTER A TURN IS
COMPLETED
 REDUCES
STEERING EFFORT
 REDUCES TIRE
WEAR

17. SYMMETERIC ANGLE B/W
WHEELS AND AXIS OFVEHICLE
FUNCTIONS
 TOE IN INCREASES
STRAIGHT LINE
STABILITY AT
COST OF TURNING
RESPONSE
 GREATER THE TOE
FASTER THE TIRE
WEARS

18. TOE-IN TOE-OUT

19. ANGLE B/W GEOMETRIC CENTRELINE AND
THRUST LINE
FUNCTIONS
 OCCURS WHEN REAR
WHEEL HAS
IMPROPER
ALIGNMENT
 EFFECTS DIRECTION
OF TRAVEL BY
CAUSING PULL IN THE
DIRECTION AWAY
FROM THRUST LINE

20.  The turning circle of a car is the diameter of the circle
described by the outside wheels when turning on full lock.
There is no hard and fast formula to calculate the turning
circle but you can get close by using this
Turning circle radius = (track/2) + (wheelbase/
sin(average steer angle))

21.  SYSTEM AUTOMATICALLY STEERS
THE REAR WHEELS ACCORDING TO
SPEED OF VEHICLE AND STEERING
ANGLE.
 USED IN MILITARY, OFF ROAD
VEHICLES, BUSES, TRUCKS AND
LARGE VAHICLS
 INCREASES HANDLING AND
STABILITY
 REDUCES TURNING RADIUS

23.  VEHICLE STEERS BY POWER ASSIST
FROM EXTERNAL SOURCE OTHER
THAN DRIVER’S EFFORT
 HELPS IN STEERING OF HEAVY
VEHICLES
 INCREASES THE STEERING RATIO
AND REDUCES DRIVER’S EFFORT
 TWO MAJOR TYPES – HPS AND EPS

26. Thank you