term paper of tom g4901

8/8/2019 Term Paper of TOM g4901

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TERM PAPER OF THEORY OF

MACHINES

TOPIC:-Study of various steering mechanism for

Different types of wheel drives.

SUBMITTED TO:-

MR. RAJEEV KUMAR

MECH. DEPT, LPU

SUBMITTED BY:-

NaME:- ABHISHEKKUMAR SINGH

REG.NO:-

10905059

SECTION: - G4901

ROLL NO.:- B44


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ACKNOWLEDGEMENT

Firstly I am very thankful to almighty GOD.I would like to

thank all those who encouraged me to complete this termpaper project .I thank heartily, Mr. RAJEEV KUMAR, my

young and dynamic teacher for his whole hearted co-

operation and support, without his involvement this

project would not have been possible. I am also thankful

to all faculties and non-teaching staff of this university

who have directly or indirectly helped me in this project

.In spite of my best efforts ,some errors might have crept

in for which I beg to excused with promise that theseerrors will be removed in the next project.

CONTENTS:-

Introduction

An overview of terms related to the term

PAPER TOPIC

Problem definition and its solution

Scope of future work

CONCLUSION

References

INTRODUCTION:-


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My term paper is based on the study of Various steering mechanism for

different types of wheels drives ". In this term paper project first of all I would like to define the

terms related to my term paper topic like wheels, steering etc. After defining these topics I define

the basic or main problem of my term paper and I will give an appropriate solution. After that I

will put some results related to my topic that I have found during my working period of term

paper project. And my second last topic is related to conclusion of my work or you can say

abstract of my term paper. At last I will give the future scope of different types of steering

mechanism for different types of wheel drives. And on the last page of this term paper I will give

the proper name of references from where I got the study materials.

AN OVERVIEW OF TERMS RELATED TO TERM PAPER TOPIC:-

What is an steering?

Steering the term applied to the collection of components, linkages, etc.

Which will allow a vessel or vehicle to follow the desired path. A picture of common steering isgiven below:- :-

What is a mechanism?

A combination of a number of bodies assembled in such a way that the

motion of one causes constraints and predictable motion to the others is known as mechanism.

Thus the function of mechanism is to transmit and modify a motion. Ex. Single slider cranks

mechanism.


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What is drive wheel?

A drive wheel is a road wheel in an automotive vehicle that receives

torque from the power train, and provides the final driving force for a vehicle. A two-wheel drive

vehicle has two driven wheels, and a four-wheel drive has four, and so-on. The name of some

common types of wheel drive is given below:-

Front wheel drive

Rear wheel drive

Two wheel drive

Four wheel drive and so on.

PROBLEM DEFINITION AND ITS SOLUTION:-

The objective of this term

paper is to study the various types of steering mechanism for the different types of wheel drives.

To understand the problem and the solution I will start from steering mechanism.

A mechanism by which something is steered, especially a motor vehicle is called a steering

mechanism. A figure of common type of steering mechanism is given below

when we turn our car, the front wheels are not pointing in the same direction. For a car to turn

smoothly, each wheel must follow a different circle. Since the inside wheel is following a circle

with a smaller radius, it is actually making a tighter turn than the outside wheel. The geometry of

the steering linkage makes the inside wheel turn more than the outside wheel.


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two most common types of steering mechanism work: rack-and-pinion and recirculating-ball

steering. The description of both types of steering mechanism is given below:-

1] RACK AND PINION STEERING: -Rack-and-pinion steering is quickly becoming the most

common type of steering on cars, small trucks and SUVs. It is actually a pretty simple

mechanism. A rack-and-pinion gear set is enclosed in a metal tube, with each end of the rack

protruding from the tube. A rod, called a tie rod, connects to each end of the rack.

2] RECIRCULATING BALL STEERING: -Recalculating-ball steering is used on many trucks

and SUVs today. The linkage that turns the wheels is slightly different than on a rack-and-pinion

system. The recalculating-ball steering gear contains a worm gear. We can image the gear in two

parts. The first part is a block of metal with a threaded hole in it. This block has gear teeth cut

into the outside of it, which engage a gear that moves the pitman arm (see diagram above). The


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steering wheel connects to a threaded rod, similar to a bolt that sticks into the hole in the block.

When the steering wheel turns, it turns the bolt. Instead of twisting further into the block the way

a regular bolt would, this bolt is held fixed so that when it spins, it moves the block, which

moves the gear that turns the wheels.

The another type of steering mechanism is power steering: - There are a couple of keycomponents in power steering in addition to the rack-and-pinion or recirculating-ball mechanism.

The hydraulic power for the steering is provided by a rotary-vane pump. This pump is driven by

the car's engine via a belt and pulley.A power-steering system should assist the driver only when he isexerting force on the steering wheel (such as when starting a turn). When the driver is not exerting force

(such as when driving in a straight line), the system shouldn't provide any assist. The device that senses

the force on the steering wheel is called the rotary valve. The key to the rotary valve is a torsion bar.

The torsion bar is a thin rod of metal that twists when the torque is applied to it. As the bartwists, it rotates the inside of the spool valve relative to the outside. Since the inner part of the


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spool valve is also connected to the steering shaft and therefore to the steering wheel.

DRIVE WHEEL:-

A vehicle's drive wheel is the wheel and tire assembly that actually pushes or pulls the vehicle

down the road. In a rear-wheel drive vehicle, the drive wheel is located in the rear of the vehicle.

In front-wheel drive applications, the drive wheel is situated in the front of the vehicle. In an all-

wheel drive type vehicle, the drive wheel is actually a pair of wheels with one front wheel and

one rear wheel receiving power on a constant basis and the other wheels receiving power as the

on-board computer deems necessary. A configuration diagram for drive wheel is given below:-

Types of drive wheel:-

1].REAR WHEEL DRIVE:- Rear-wheel drive or RWD for short was a common internal

combustion engine layout used in automobiles throughout the 20th century.RWD typically


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places the engine in the front of the vehicle, but the mid engine and rear engine layouts are also

used.

2].FRONT WHEEL DRIVE:- . The first documented front-wheel-drive vehicle is said by various

sources to have been produced by Graf and Stiff sometime between 1895 and 1898. During this

time, they produced the De Dion-Bouton engine, which ran on one cylinder and powered the

vehicle's front axle. In addition, the engine was located at the front of the vehicle. Fiat made

front-wheel drive popular in 1969. Front-wheel drive is the most common form of internal

combustion engine used in modern passenger cars, where the engine drives the front wheels.

Most front wheel drive vehicles today feature transverse engine mounting, whereas in past

decades engines were mostly positioned longitudinally instead. Rear-wheel drive was the

traditional standard, and is still widely used in luxury cars and most sport cars. Four-wheel drive

is also sometimes used.


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3].TWO WHEEL DRIVE:-For four-wheeled vehicles, this term is used to describe vehicles that

are able to transmit torque to at most two roadwheels, referred to as either front- or rear-wheel

drive. The term 4x2 is also used, to denote four total roadwheels with two being driven.For

vehicles that have part-time four-wheel drive, the term refers to the mode when 4WD is

deactivated and torque is applied to only two wheels. For two-wheeled vehicles such as

motorcycles and bicycles, the term is used to describe vehicles which can power the front as well

as the back wheel. The term 2x2 is also used to denote two total wheels with both being driven.

2x2 vehicles are typically either mechanically driven via chain or shaft or are hydraulic driven.

This scheme greatly improves off-road performance, but is quite complicated and requires more

power to operate.

4].FOUR WHEEL DRIVE:- The true inventor of four-wheel drive is not really known; the

history of such was not well recorded. In 1893, before the establishment of a modern automotive

industry in Britain, English engineer Braham Joseph Diplock patented a four wheel drive system

for a traction engine. Usually, when carmakers say that a car has four-wheel drive, they are

referring to a part-time system.These systems are meant only for use in low-traction conditions,

such as off-road or on snow or ice. Four-wheel drive, 4WD, is a four-wheeled vehicle with a

drive train that allows all four wheels to receive torque from the engine simultaneously. The term

four-wheel drive is used interchangeably with all-wheel drive and describes the ability of a

vehicle to transfer the engine's power to all four wheels. The majority of vehicles on the road do

not offer this feature, as either the front or rear wheels are driven by the engine's power.

However, a four-wheel drive system offers a distinct advantage when traction is limited in

slippery conditions such as on snow, mud, loose gravel or sand. Most of the four-wheel drive

systems offered today can be broken down into two main categories:-

a).Part Time Four Wheel Drive:-Part-time four wheel drive: As its name implies, this

form of four-wheel drive powers all four wheels only when the 4WD mechanism is engaged.

Typically, these systems power the rear wheels during ideal weather conditions to reduce the

wear on the drive train and improve fuel economy. However, when four wheel drive is engaged,

engine power is transferred to the front wheels as well as the rear.


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b).All Wheel Drive:-This system is gaining popularity in the newer cars and trucks. In a

typical all-wheel drive system all four wheels are powered at all times. However, unlike a true

four-wheel drive vehicle, the power split between the front and rear axles are not set at a fixed

value (typically 50% front, 50% rear) but can be varied depending on available traction.

A below given figure shows the basic construction of a four wheel drive:-

SCOPE OF FUTURE WORK:- The discussion given in this section is totally based on

the new advancements in steering mechanism and wheel drive. What kind of improvement will

take place in future.

Automobile Steering System: Automobile steering is one of most necessary system of any

automobile. This is getting better and more better during the years and technological advances.

We have already seen some basic automobile steering system like below:

1].Manual Steering System.

2].Power Assisted Steering System.

3].Electro-Hydraulic Steering System.

Below I have discussed some future technological systems related to automobile steering.

1. Magna-steering systems: In this system, steering of automobile is achieved through steering

gear rotary valve, with a magnetically controlled variable rate torsion bar. This system has some

unique advantages, apart from old systems.

Advantages of Magna-steering systems: This design is very flexible and can be accommodate

as per need and space availability. It employs the non-contact mechanism. i.e. no mechanical

parts contact with each other which reduces the chances of friction between them and hence wear

and tear of parts. Non-contact mechanisms have one more advantage. It reduces the insertion of

backlash in the system performance. System includes less moving parts and hence better and


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long life performance. This system can be integrated with computer and it can be tuned as per

need of driver and ride. This phenomenon is called as the laptop tuning of the system.

2. Four wheel steering (Quadra-steering) System: As name suggests, it includes steering with

4 wheels. i.e. all 4 wheels turn in unison to get optimum turning. This system is simple to

visualize but hard designing and employing in the practical. This system is also called as ZeroTurning Radius.

Advantages of Four Wheel Steering: This system improves the vehicle performance and

stability at higher speeds. Increases stability in lane change maneuvers. Increased

maneuverability while driving/tugging trailers at low speeds. Turning circle diameter is

significantly reduced.

3. Steer By Wire System (SBW): This system eliminates the hydraulic fluid. Much hardware is

reduced here which is definitely good for mechanical system. It integrates front as well as rear

wheels which gives steering capability to front as well rear wheels. Electrical interface forsystem generation. These are various Future Trends of Automobile Steering System.

After that the new advancement in various types of wheel drives is considered by the giant

auto companies. A brief view of some of them is given below:-

1).BMW is considering a front-wheel drive joint platform for its small cars, to be shared with

MINI.

2).General Motors' two mode hybrid power train, used only in trucks, will migrate to rear-drive

cars in the next generation.

3).British 4x4 specialist plans two-wheel drive future for Range Rover and Freelander models.

Land Rover is plotting the launch of the first front wheel drive model in its history, Auto Express

can reveal.

4).While cross country rivals Lamborghini have sworn off diesels and hybrids--at least for the

immediate future Ferrari is said to be at work on a new flavor of four-wheel drive that uses

hybrid gas-electric power to generate the traction.

5).In addition some leading auto manufacturers try to use the developed steering mechanism for

different types of wheel drives in agricultural tractors and also in bicycles.

CONCLUSION:-

My term paper topic is based on the study of various types of steering

mechanism for different types of wheel drives. During the study of this topic I have conclude

that this is the basic part of all kind of transportation system. There are various types of steering

mechanism and wheel drives developed by auto engineers but we need some new advancement


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in this field. There are some kind of future advancement is given by some companies but this

developments takes place only in costly cars. We need to develop new system to reduce the cost

and increase durability of system. Although some companies doing work in this field which is

appreciable.

REFERENCES:-

1. http://www.r32argent.com

2. http://cwbbs.net

3. http://www.wisegeek.com

4. http://auto.howstuffworks.com

5. http://www.2carpros.com

6. http://www.engiblogger.com

7. http://www.motorauthority.com

8. http://editorial.autos.msn.com

9. http://www.autoexpress.co.uk
http://www.motorauthority.com/http://editorial.autos.msn.com/http://www.autoexpress.co.uk/http://www.motorauthority.com/http://editorial.autos.msn.com/http://www.autoexpress.co.uk/

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