About 4W steering in automotive

1. FABRICATION OF OPTIONAL
FOUR WHEEL STEERING
SYSTEM
SIR C.R REDDY COLLEGE OF ENGINEERING, ELURU
K.S. SARAN KUMAR
(315277133004)
M.E (Machine Design)

2. CONTENTS
 INTRODUCTION AND SYNOPSIS
 TYPES OF STEERING
 FABRICATION OF FOUR WHEEL STEERING SYSTEM
 MECHANISM USED IN FOUR WHEEL STEERING
 WORKING OF FOUR WHEEL STEERING MECHANISM
 ADVANTAGES
 CONCLUSION

3. Aim
Development of Four Wheel Steering System
Introduction
4 Wheel Steering System is employed in vehicles to achieve
better manoeuvrability at reducing the turning radius of the
car and to reduce the driver's steering effort. In most active
4 wheel steering system, the guiding computer or electronic
equipment play a major role, in our project we have tried to
keep the mechanism only by mechanical aid which can be easy
to manufacturing and maintenance.

4. SYNOPSIS
 In standard 2 Wheel Steering System, the rear set of wheels
are always directed forward and do not play an active role in
controlling the steering.
 While in 4 Wheel Steering System, the rear wheels do play
an active role for steering, which can be guided at high as
well as low speeds.
 If a car could automatically compensate for an under
steer/over steer problem, the driver would enjoy nearly
neutral steering under varying operating conditions.
 Also in situations like low speed cornering, vehicle parking
and driving in city conditions with heavy traffic in tight
spaces, driving would be very difficult due to a sedan’s larger
wheelbase and track width.

5. Steering Types
The 4WS system performs two distinct operations:
• In- phase steering, whereby the rear wheels are turned
in the same direction as the front wheels
• Counter phase steering, whereby the rear wheels are
turned in the opposite direction

6. In-Phase Mode
 At High Speeds, turning the rear wheels through an angle
opposite to front wheels might lead to vehicle instability and is
thus unsuitable.
Hence the rear wheels
are turned in the same
direction of front
wheels in four-wheel
steering systems.

7. Counter-Phase Mode
 At Slow Speeds rear wheels turn in direction opposite to
that of front wheels.
 This mode is used for
navigating through hilly
areas and in congested
city where better
cornering is required for
U turn and tight streets with
low turning circle which can be reduced.

8. Rear Frame Transformation
 The rear frame for the type-1 MARUTHI 800 is altered.
 The wheel disc with drum brakes has taken out
 Coil spring with gas-filled shock absorbers has to be
retained
 Alteration has to be done between the flat plate clamp and
wheeler drum

10. Fabrication
 The front axle of TATA ACE is dissembled and the
wheel discs are fitted to MARUTHI 800
 To the rear axle two inches of seamless rod is welded
on either ends.
 To this rear wheels are fixed.

11. Mechanism of four wheel
steering
 The steering column with
universal joint has
to be altered.
 Bevel gears
are fitted to the
steering linkage.

12. Mechanism of Four wheel steering
 The model consists of front rack and pinion mechanism
assisted by two bevel gears of which one is connected to
a)Telescopic shaft
b)one is connected to steering rod in which input is given by
the driver .

13. Mechanism used
o To the telescopic shaft a yoke and teeth is welded . It is used
for engaging and disengaging.
o Since it is an optional four wheel steering , two wheel
steering or four wheel steering can be obtained by just
adjusting the lever.

15. Mechanism Used
At the rear end, Another Rack and Pinion mechanism is used
to change the direction of the wheels from the feed rod.

16. Mechanism
 To the rear end, a rack and pinion is attached .
 The movement for the pinion is achieved from the steering
wheel.
 Rack and pinion is supported by the L-shaped frames and is
fixed to rear axle.

17. Working
 IN-PHASE is achieved when the yoke and teeth is engaged to
Telescopic shaft
 In IN-PHASE, angle turned by rear wheels will be similar to
that of front wheels because the function of rear steering
system is to assist the motion of front wheels and not provide
its own direction.
 Incase of In phase , the front and rear wheels will turn in 1:1
ratio.

18. Working
 Counter phase is achieved by paralleling the wheels
and then disengaging the yoke and teeth and then
changing the direction of the front wheels.

19. Advantages
The 4WS system is effective in the following situations:
 Lane Changes
 Gentle Curves
 Junctions
 Narrow Roads
 U-Turns

21. Conclusion
 This type of steering is much preferable in heavy traffics and
congested roads.
 Parallel parking is the most adoptable mechanism for the
Indian roads.
 If everything goes well , this type of steering will be
implemented in all the future cars to achieve better
maneuverability.

22. Thank You