STEERING

IS STEERING REQUIRED FOR A VEHICLE?

DO TWO WHEELER HAVE STEERING?

•Control of front wheel (sometimes rear wheel) direction.

•Maintain correct amount of effort needed to turn the wheels.

•Absorb most of the shock going to the steering wheel as the tire hits holes and bumps in the road.

Functions of steering

STEERING TERMINOLOGY

•Instantaneous centre •Track width•Wheelbase•Inner angle •Outer angle•Turning radius•Steering ratio

cotδo-cotδi = w/lAckermann condition is given byi

δ0δI

δ0δIW

l

O (Instantaneous Centre)

STEERING GEOMETRY

•Acckermann Geometry•Davis Geometry

DIFFERENCE BETWEEN ACKERMANN AND DAVIS GEOMETRIES

ACKERMANN GEOMETRY DAVISGEOMETRY

•APPROXIMATED GEOMETRY•TURNING PAIRS•PROJECTED TOWARDS FRONT OF FRONT AXLE

•ACCURATE GEOMETRY•SLIDING PAIRS•PROJECTED FORWARD OF FRONT AXLE

TYPES OF STEERING•MANUAL STEERING •POWER ASSISTED STEERING

STEERING PARTS•Steering wheel•Steering Column•Tie rod •Steering arm•Rack and pinion

Steering Mechanisms•Trapezoidal steering mechanism•Rack and pinion mechanism•Parallelogram steering mechanism•Halten Burger mechanism•Re-circulating ball type

Trapezoidal Steering Mechanism

W

β d

w

β

Rack and pinion steering

•Rack- long steel bar with teeth along one section;• slides sideways as the pinion gear turns.

•Pinion Gear- rotated by the steering wheel and steering shaft;• it’s teeth mesh with the teeth on the rack.

HALTEN BURGER MECHANISM

STEERING RATIO : The Steering ratio is the ratio of the turn of steering wheel to that of turn of wheelsEx: Steering ratio of street cars is around 10 : 1 Race cars varies between 5:1to 20 : 1. Bicycle 1:1

STEERING EFFORT

•The minimum effort applied by the driver to rotate the steering wheel

WHEEL ALIGNMENT

CASTER ANGLE CAMBER ANGLETOE(TOE IN AND TOE OUT)KINGPIN INCLINATION(SWIVEL AXIS INCLINATION)

Camber angle

Caster angle

toe

KINGPIN INCLINATION

•The angle formed by a line drawn through the upper and lower pivot points of the steering axis and a vertical line as viewed from the front

•The King Pin Inclination of an axis of turn provides weight stabilization and steady movement of the automobile on a straight line and in turns.

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