STEERING SYSTEM

PRESENTED BY :

Madhusudan Dahal

Mechanical engg.Batch 2012-16

CONTENTS

•INTRODUCTION

•REQUIREMENTS

•FUNCTION OF STEERING SYSTEM

•STEERING PRINCIPLE

•TYPES OF STEERING SYSTEM

INTRODUCTION WHAT IS A STEERING SYSTEM ?

HOW A STEERING SYSTEM WORKS ?

Fig showing rack and pinion steering system

Fig showing rack and pinion power steering

fig showing electric power steering system

REQUIREMENTS• Multiply the turning effort applied on steering wheel by the driver

• It should be to a certain degree irreversible

• The mechanism should have self-rightening effect

FUNCTIONS OF A STEERING SYSTEM

• To control the angular motion of the wheels and thus the direction of motion of the vehicle.

• To provide directional stability of the vehicle while going straight ahead.

• To facilitate straight ahead condition of the vehicle after completing a turn.

• To minimize tyre wear and increase it’s life.

ACKERMANN’S PRINCIPLE

The intention of Ackermann geometry is to avoid the need for tyres to slip sideways when following the path around a curve.

Excess of Ackermann angle from true will result in

• it will make the car loose on turn exit or will cause premature tyre wear.

• too much Ackermann can also over-heat the left front tyre so that it will not perform on a long journey.

CONSTRUCTION OF STEERING MECHANISM

CONDITIONS FOR

PROPER STEERING The fundamental equation for correct steering and no skidding of the wheels, when the vehicle takes a turn is

cot φ – cot Ө = c/b

This:• this turns all the four wheels about the same instantaneous center of rotation and

• prevents the excess wear of tyres.

DIFFERENCE ACKERMANN MECHANISM

DAVIS MECHANISM

Mechanism is in the back of the front wheels

Mechanism is in the front of front wheels

Consists of turning pair so less friction and wear

Consists of sliding pair so more friction and wear

Positions of correct gearing are: It is an exact steering gear mechanism and fulfils the fundamental equation of

gearing in all the positions.

When the vehicle moves straight

When the vehicle moves a correct angle to the right and left

In other positions slippage occurs  

STEERING GEOMETRY

Ackermann steering geometry is a geometric

arrangement of linkages in the steering of a car for it to

turn smoothly. This helps in turning the inner wheel with

a larger angle than the outer wheel leading to rolling of

the wheels rather than slipping.

  

STEERING GEAR

• Converts the rotational motion of the steering wheel to the linear motion and

•It provides a gear reduction, making it easier to turn the wheels Types :

•Rack and pinion •Re -circulating ball •Cam and roller•Worm and sector•Worm and roller

RACK AND PINION STEERING GEAR

THE END

THANK YOU.