DESIGN AND IMPLENTATION OF REVERSE GEAR

MECHANISM IN SHAFT DRIVEN TWO WHEELERS

A PROJECT REPORT

Submitted by

HARIPIRASTH D S (412411114017)

PREM KUMAR G R (412411114037)

ABISHEK A (412411114301)

In partial fulfillment of the award of the degree

Of

BACHELOR OF ENGINEERING

IN

MECHANICAL ENGINEERING

SRI SAIRAM INSTITUTE OF TECHNOLOGY, CHENNAI-44

ANNA UNIVERSITY: CHENNAI 600025

APRIL 2015

i

ANNA UNIVERSITY::CHENNAI 600 025

BONAFIDE CERTIFICATE

Certified that this report “DESIGN AND IMPLEMENTATION OF REVERSE

GEAR MECHANISM IN SHAFT DRIVEN TWO WHEELERS” is the

bonafide work of “HARIPIRASATH D S (412411114017), PREM KUMAR G

R (412411114037), ABISHEK A (412411114301)” who carried out under my

supervision.

SIGNATURE

Mr.A.SRITHAR,M.E.,

HEAD OF THE DEPARTMENT

Department of Mechanical Engineering

Sri Sai Ram Institute of Technology

Chennai – 600044

SIGNATURE

Mr. M.MAREESWARAN, M.E.,

SUPERVISOR, ASST. PROFESSOR,

Department of Mechanical Engineering

Sri Sai Ram Institute of Technology

Chennai – 600044

Submitted for the ANNA UNIVERSITY Examination held on____________

at SRI SAIRAM INSTITUTE OF TECHNOLOGY, Chennai- 44.

INTERNAL EXAMINER EXTERNAL EXAMINER

ii

ACKNOWLEDGEMENT

We express our deep sense of gratitude to our beloved Chairman

Thiru.MJF.Ln.LEO MUTHU for the help and advice he has shared upon us.

We express our gratitude to our CEO Mr.J.SAI PRAKASH LEO MUTHU

and our Trustee Mrs.J.SHARMILA RAJAA for their constant encouragement in

completing the project.

We express our solemn thanks to our esteemed Principal

Dr.K.PALANIKUMAR for having given us spontaneous and wholehearted

encouragement for completing this project.

We are indebted to our HOD Mr. A. SRITHAR for his support during the

entire course of this project work.

We express our gratitude and sincere thanks tour guide

Mr.M.MAREESWARAN, Asst. Professor for his valuable suggestions and

constant encouragement for successful completion of this project.

Our sincere thanks to our project coordinator Mr.G.SHANMUGA

SUNDAR, Asst. Professor for his kind support in bringing out this project

successfully.

Finally, we thank all the teaching and Non-teaching staff members of the

Department of Mechanical Engineering and all others who contributed directly

or indirectly for the successful completion of our project.

iii

ABSTRACT

At present, the chain driven bikes have been a great trouble in aspects of

maintenance, cleanliness, power transmission etc .So to overcome these effects we

have replaced the chain driven bikes by shaft mechanisms and also have indulged a

reverse mechanism in bikes as there is no system available to reverse the vehicle.

At times when the front wheel gets into a trench it is very difficult to take the

vehicle from parking. Even normal people face much problem to take the vehicle

out of the parking at that time. In order to take the vehicle out of the parking they

need to seek others help or they should push it out of the parking. Also for

handicapped people it is impossible to take reverse from the parking. As a help to

them we have designed a gear position which will be fit to the vehicle without

altering the existing gear. The paper deals with the design of such a gear position

and the assembly process of the gear to the vehicle.

iv

TABLE OF CONTENTS

CHAPTER

NO.

TITLE PAGE NO.

ACKNOWLEDGEMENT

ABSTRACT

LIST OF FIGURES

iii

iv

viii

1. INTRODUCTION 1

1.1 HISTORY OF BICYCLES 1

1.2 REVERSE DRIVEN BICYCLE 2

1.3 CHAIN DRIVEN BIKES 3

1.3.1 HISTORY 4

1.4 SHAFT DRIVEN BIKES 5

1.5 REVERSE GEAR IN BIKE 9

2. LITERATURE SURVEY 11

2.1 DESIGN AND FABRICATION OF 11

SHAFT DRIVEN BICYCLE

2.2 DRIVE SHAFT MECHANISM IN 12

MOTOR VEHICLE

2.2.1 FABRICATION AND WORKING 12

2.3 DEVELOPMENT AND IMPLENTATION 13

OF REVERSE GEAR MECHANISM IN

BIKE

2.4 ROADSTER CYCLE 14

v

CHAPTER

NO.

TITLE PAGE NO.

3 COMPONENTS 15

3.1 BEVEL GEAR 15

3.1.1 INTRODUCTION 16

3.1.2 TYPES 17

3.1.3 GEOMETRY OF BEVEL GEAR 19

3.1.4 ADVANTAGES 20

3.1.5 DISADVANTAGES 20

3.2 SHAFT DRIVE 20

3.3 DC MOTOR 22

3.3.1 ELECTRO MAGNETIC MOTOR 23

3.4 COTTER JOINT 25

3.4.1 TYPES OF COTTER JOINT 26

3.4.1.1 SOCKET AND SPIGOT JOINT 27

3.4.1.2 SLEEVE AND COTTER JOINT 27

3.4.1.3 GIB AND COTTER JOINT 28

3.4.2 APPLICATION OF COTTER JOINT 29

3.4.3 COMPARISON BETWEEN KEY AND 29

COTTER JOINT

vi

CHAPTER

NO.

TITLE PAGE NO.

4 OPERATION 30

4.1 LATHE 30

4.2 ARC WELDING 31

4.2.1 OPERATION 31

4.3 CYLINDRICAL GRINDING MACHINE 33

4.3.1 APPLICATIONS 34

4.4 BROACHING 35

4.4.1 PROCESS 36

4.4.2 USAGE 37

5 CONSTRUCTION AND WORKING 38

5.1 WORK METHODOLOGY 40

5.2 WORKING 40

5.2.1 REVERSE DIRECTION 40

5.2.2 FORWARD DIRECTION 41

5.3 DESIGN CALCULATION 41

6 CONCLUSION 45

7 REFERENCE 46

vii

LIST OF FIGURES

FIG NO. CAPTION PAGE

NO.1.1 shaft driven bicycle 2

1.2 Chain Driven Two Wheeler 4

1.3 Shaft Drive Two Wheeler 6

1.4 Comet Gear Box 10

2.1 Shaft Drive Bicycle Components 11

2.2 Shaft Driven Bike Components 12

2.3 Roadster Cycle 14

3.1 Bevel Gear 15

3.2 Bevel Gear Terminology 16

3.3 Milter and Its Mating Gear 17

3.4 Spiral Gear 18

3.5 Double Helical Gear 19

3.6 Exposed drive shaft on BMW's R 32 21

3.7 DC Motor with Worm Gear 22

3.8 Cotter joint and its Components 26

3.9 Socket and Spigot Joint 27

3.10 Sleeve and Cotter Joint 28

3.11 Gib and Cotter Joint 28

4.1 Lathe 30

4.2 Arc Welding 32

4.3 Cylindrical Grinding Machine 34

5.1 Project in Top View in PRO-E Model 38

FIG NO. CAPTION PAGE

NO.

viii

5.2 Model in PRO-E 39

5.3 Project Fabrication 39

5.4 Lever when shifted right 40

5.5 Lever when shifted left 41

ix

CHAPTER 1

INTRODUCTION

1.1 HISTORY OF BICYCLE

A bicycle, often called a bike or cycle, is a human-powered, pedal-

driven, single-track vehicle, having two wheels attached to a frame, one behind the

other. A bicycle rider is called a cyclist, or bicyclist.

Bicycles were introduced in the 19th century in Europe and, as of 2003, more

than a billion have been produced worldwide, twice as many as the number

of automobiles that have been produced. They are the principal means of

transportation in many regions. They also provide a popular form of recreation,

and have been adapted for use as children's toys, general fitness, military and

police applications, courier services, and bicycle racing.

The basic shape and configuration of a typical upright, or safety bicycle, has

changed little since the first chain-driven model was developed around 1885. But

many details have been improved, especially since the advent of modern materials

andcomputer-aided design. These have allowed for a proliferation of specialized

designs for many types of cycling.

The bicycle's invention has had an enormous effect on society, both in terms of

culture and of advancing modern industrial methods. Several components that

eventually played a key role in the development of the automobile were initially

invented for use in the bicycle, including ball bearings, pneumatic tires, chain-

driven sprockets, and tension-spoked wheels.

The word bicycle first appeared in English print in The Daily News in 1868, to

describe "Bysicles and trysicles" on the "Champs Elysées and Bois de

1

Boulogne.”. The word was first used in 1847 in a French publication to describe an

unidentified two-wheeled vehicle, possibly a carriage. The design of the bicycle

was an advance on the velocipede, although the words were used with some degree

of overlap for a time.

Other words for bicycle include "bike", "pushbike", "pedal cycle", or

"cycle". In Unicode, the hexadecimal code for "bicycle" is 1F6B2. The

string & produces.

1.2 REVERSE DRIVEN BICYLES

Fig 1.1 Shaft Driven Bicycle

A shaft-driven bicycle is a bicycle that uses a drive shaft instead of a chain to

transmit power from the pedals to the wheel. Shaft drives were introduced over a

century ago, but were mostly supplanted by chain-driven bicycles due to the gear

ranges possible with sprockets and derailleurs. Recently, due to advancements in

internal gear technology, a small number of modern shaft-driven bicycles has been

introduced. Shaft-driven bikes have a large bevel gear where a conventional bike

would have its chain ring. This meshes with another bevel gearmounted on the 2

drive shaft. The use of bevel gears allows the axis of the drive torque from the

pedals to be turned through 90 degrees. The drive shaft then has another bevel gear

near the rear wheel hub which meshes with a bevel gear on the hub where the rear

sprocket would be on a conventional bike, and canceling out the first drive torque

change of axis.

The 90-degree change of the drive plane that occurs at the bottom bracket and

again at the rear hub uses bevel gears for the most efficient performance, though

other mechanisms could be used, e.g. hobson's joints, worm gears or crossed

helical gears.

The drive shaft is often mated to a hub gear which is an internal gear system

housed inside the rear hub. Manufacturers of internal hubs suitable for use with

shaft drive systems include NuVinci, Rohloff, Shimano, SRAM, and Sturmey-

Archer.

1.3 CHAIN DRIVEN BIKES

Chain drive is a way of transmitting mechanical power from one place to

another. It is often used to convey power to the wheels of a vehicle, particularly

bicycles and motorcycles. It is also used in a wide variety of machines besides

vehicles.

Most often, the power is conveyed by a roller chain, known as the drive

chain or transmission chain, passing over a sprocket gear, with the teeth of the gear

meshing with the holes in the links of the chain. The gear is turned, and this pulls

the chain putting mechanical force into the system. Another type of drive chain is

the Morse chain, invented by the Morse Chain Company of Ithaca, New

York, USA. This has inverted teeth.

3

Sometimes the power is output by simply rotating the chain, which can be used

to lift or drag objects. In other situations, a second gear is placed and the power is

recovered by attaching shafts or hubs to this gear. Though drive chains are often

simple oval loops, they can also go around corners by placing more than two gears

along the chain; gears that do not put power into the system or transmit it out are

generally known as idler-wheels. By varying the diameter of the input and output

gears with respect to each other, the gear ratio can be altered, so that, for example,

the pedals of a bicycle can spin all the way around more than once for every

rotation of the gear that drives the wheels.

Fig 1.2 Chain Driven Two Wheeler

1.3.1 HISTORY

The oldest known application of a chain drive appears in the Polybolos,

a repeating crossbow described by the Greek engineer Philon of Byzantium (3rd

century BC). Two flat-linked chains were connected to a windlass, which by

4

winding back and forth would automatically fire the machine's arrows until its

magazine.

Although the device did not transmit power continuously since the chains "did

not transmit power from shaft to shaft, and hence they were not in the direct line of

ancestry of the chain-drive proper", the Greek design marks the beginning of the

history of the chain drive since "no earlier instance of such a cam is known, and

none as complex is known until the 16th century”. It is here that the flat-link chain,

often attributed to Leonardo da Vinci, actually made its first appearance”.

The first continuous and endless power-transmitting chain was depicted in the

written horological treatise of the Song Dynasty (960–1279) Chinese engineerSu

Song (1020-1101 AD), who used it to operate the armillary sphere of

his astronomical clock tower as well as the clock jack figurines presenting the time

of day by mechanically banging gongs and drums. The chain drive itself was

given power via the hydraulic works of Su's water clock tank and waterwheel, the

latter which acted as a large gear.

1.4 SHAFT DRIVEN BIKES

A shaft-driven bicycle is a bicycle that uses a drive shaft instead of a chain to

transmit power from the pedals to the wheel. Shaft drives were introduced over a

century ago, but were mostly supplanted by chain-driven bicycles due to the gear

ranges possible with sprockets and derailleurs. Recently, due to advancements in

internal gear technology, a small number of modern shaft-driven bicycles has been

introduced.

Shaft-driven bikes have a large bevel gear where a conventional bike would

have its chain ring. This meshes with another bevel gear mounted on the drive

shaft. The use of bevel gears allows the axis of the drive torque from the pedals to

be turned through 90 degrees. The drive shaft then has another bevel gear near the

5

rear wheel hub which meshes with a bevel gear on the hub where the rear sprocket

would be on a conventional bike, and canceling out the first drive torque change of

axis.

Fig 1.3 Shaft Drive Two Wheeler

The 90-degree change of the drive plane that occurs at the bottom bracket and

again at the rear hub uses bevel gears for the most efficient performance, though

other mechanisms could be used, e.g. hobson's joints, worm gears or crossed

helical gears.

The drive shaft is often mated to a hub gear which is an internal gear system

housed inside the rear hub. Manufacturers of internal hubs suitable for use with

shaft drive systems include NuVinci, Rohloff, Shimano, SRAM, and Sturmey-

Archer.

6

The oldest known application of a chain drive appears in the Polybolos,

a repeating crossbow described by the Greek engineer Philon of Byzantium (3rd

century BC). Two flat-linked chains were connected to a windlass, which by

winding back and forth would automatically fire the machine's arrows until its

magazine was empty.

Although the device did not transmit power continuously since the chains "did

not transmit power from shaft to shaft, and hence they were not in the direct line of

ancestry of the chain-drive proper", the Greek design marks the beginning of the

history of the chain drive since "no earlier instance of such a cam is known, and

none as complex is known until the 16th century".  It is here that the flat-link

chain, often attributed to Leonardo da Vinci, actually made its first appearance”.

The first continuous and endless power-transmitting chain was depicted in the

written horological treatise of the Song Dynasty (960–1279) Chinese engineerSu

Song (1020-1101 AD), who used it to operate the armillary sphere of

his astronomical clock tower as well as the clock jack figurines presenting the time

of day by mechanically banging gongs and drums. The chain drive itself was given

power via the hydraulic works of Su's water clock tank and waterwheel, the latter

which acted as a large gear.

Roller chain and sprockets is a very efficient method of power transmission

compared to (friction-drive) belts, with far less frictional loss. Although chains can

be made stronger than belts, their greater mass increases drive train inertia. Drive

chains are most often made of metal, while belts are often rubber, plastic, urethane,

or other substances. Drive belts can slip unless they have teeth, which means that

the output side may not rotate at a precise speed, and some work gets lost to

the friction of the belt as it bends around the pulleys. Wear on rubber or plastic

7

belts and their teeth is often easier to observe, and chains wear out faster than belts

if not properly lubricated.

One problem with Roller Chains is the variation in speed, or surging, caused by

the acceleration and deceleration of the chain as it goes around the sprocket link by

link. It starts as soon as the pitch line of the chain contacts the first tooth of the

sprocket. This contact occurs at a point below the pitch circle of the sprocket. As

the sprocket rotates, the chain is raised up to the pitch circle and is then dropped

down again as sprocket rotation continues. Because of the fixed pitch length, the

pitch line of the link cuts across the chord between two pitch points on the

sprocket, remaining in this position relative to the sprocket until the link exits the

sprocket. This rising and falling of the pitch line is what causes chordal effect or

speed variation.

In other words, conventional roller chain drives suffer the potential for

vibration, as the effective radius of action in a chain and sprocket combination

constantly changes during revolution ("Chordal action"). If the chain moves at

constant speed, then the shafts must accelerate and decelerate constantly. If one

sprocket rotates at a constant speed, then the chain (and probably all other

sprockets that it drives) must accelerate and decelerate constantly. This is usually

not an issue with many drive systems, however most motorcycles are fitted with a

rubber bushed rear wheel hub to virtually eliminate this vibration issue. Toothed

belt drives are designed to avoid this issue by operating at a constant pitch radius.

Chains are often narrower than belts, and this can make it easier to shift them to

larger or smaller gears in order to vary the gear ratio. Multi-speed bicycles

with derailleurs make use of this. Also, the more positive meshing of a chain can

make it easier to build gears that can increase or shrink in diameter, again altering

the gear ratio. However, some newer synchronous belts have "equivalent capacity

8

to roller chain drives in the same width". In other words, a toothed belt as wide as a

chain drive can transmit the same, or even slightly higher, amount of power.

Both can be used to move objects by attaching pockets, buckets, or frames to

them; chains are often used to move things vertically by holding them in frames, as

in industrial toasters, while belts are good at moving things horizontally in the

form of conveyor belts. It is not unusual for the systems to be used in combination;

for example the rollers that drive conveyor belts are themselves often driven by

drive chains.

Drive shafts are another common method used to move mechanical power

around that is sometimes evaluated in comparison to chain drive; in particular belt

drive vs chain drive vs shaft drive is a key design decision for most motorcycles.

Drive shafts tend to be tougher and more reliable than chain drive, but the bevel

gears have far more friction than a chain. For this reason virtually all high

performance motorcycles use chain drive, with shaft driven arrangements generally

used for non-sporting machines. Toothed belt drives are used for some (non-

sporting) models.

Chain drive was the main feature which differentiated the safety

bicycle introduced in 1885, with its two equal-sized wheels, from the direct-

drive penny-farthing or "high wheeler" type of bicycle. The popularity of the

chain-driven safety bicycle brought about the demise of the penny-farthing, and is

still a basic feature of bicycle design today.

1.5 REVERSE GEAR IN BIKES

To reverse the shaft driven bikes such as Ducati,Harley Davidson super

bikes an gear box known as comet gear box is used that costs more than 20

9

thousand rupees in Indian rupee today.This comet gear box has an sun and gear

planet arrangement in them where the drive shaft is connected to one side of sun

gear and then the shafts from the gear are taken to the driven shaft.Thus this

arrangement helps to engage the reverse process.

Fig1.4 Comet Gear Box

The Comet Gearbox is for go-karts, utility vehicles and other applications up to

16 hp. Lightweight, rugged gearbox that allows operator the selection of three

positions: forward, neutral and reverse. Forward ratio is 1:1 and the reverse ratio is

2.7:1. Use this gearbox with a Comet torque converter system. Maximum input

shaft speed of 4000 rpm. The unit has a 5 1/2" long 3/4" keyed shaft and the

mounting pattern on the bottom is 1 3/4 x 3 15/16. It costs in a range of fifteen

thousand to thirty thousand.

10

CHAPTER 2

LITERATURE SURVEY

2.1 DESIGN AND FABRICATION OF SHAFT DRIVE FOR BICYCLE

G. Hari Prasad, S.Marurthi, R.Ganapathi, M.Janardhan, M.P.Madhu sudhan.

International Journal of Emerging Engineering Research and Technology Volume

2, Issue 2, May 2014.

This project was developed for the users to rotate the back wheel of a two

wheeler using propeller shaft. Usually in two wheelers, chain and sprocket method

is used to drive the back wheel. But in this project, the Engine is connected at the

front part of the vehicle. The shaft of the engine is connected with a long rod. The

other side of the long rod is connected with a set of bevel gears. The bevel gears

are used to rotate the shaft in 90 o angle. The back wheel of the vehicle is

connected with the bevel gear (driven). Thus the back wheel is rotated in

perpendicular to the engine shaft. Thus the two wheeler will move forward.

According to the direction of motion of the engine, the wheel will be moved

forward or reverse. This avoids the usage of chain and sprocket method.

Fig 2.1 Shaft Drive Bicycle Components

11

2.2 DRIVE SHAFT MECHANISM IN MOTOR VEHICLE

S. Vanangamudi, S. Prabhakar, C. Thamotharan and R. Anbazhagan.

Middle-East Journal of Scientific Research, IDOSI Publications, 2014

The job involved is the design for suitable propeller shaft and replacement of

chain drive smoothly to transmit power from the engine to the wheel without slip.

It needs only a less maintenance because it will not get worn out during service as

compared to chain drive. It is cost effective. Propeller shaft strength is more and

also propeller shaft diameter is less. It absorbs the shock. Because the propeller

shaft center is fitted with the universal joint is a flexible joint. It turns into any

ANGULAR position. The both end of the shaft are fitted with the bevel pinion, the

bevel pinion engaged with the crown and power is transmitted to the rear wheel

through the propeller shaft and gear box.

2.2.1 Fabrication and Working Principle:

The engine is fixed to the frame stand. There are two bevel gears are used in

this project. One bevel gear is coupled to the engine shaft and another one bevel

gear is used to transfer the energy from engine shaft to the differential unit. The

differential unit is fixed to the frame stand by the suitable arrangement. The

differential unit one end is connected to the wheel by the suitable arrangement.

12

Fig 2.2 Shaft Driven Bike Components

2.3 DEVELOPMENT AND IMPLEMENTATION OF REVERSE DRIVE

MECHANISM IN BIKES

Sathish kumar, J.Jerris, J.Purushothaman, J.Jude Shelley, A.Abdul khadeer,

Ranjeet Pokharel, J.Arshad Basha, P.Saravanan.

November 2014 in IJSR (INTERNATIONAL JOURNAL OF SCIENTIFIC

RESEARCH)

They have designed a gear box which will be fit to the vehicle without altering

the existing gear box. The paper deals with the design of such a gear box and the

assembly process of the gear box to the vehicle. The design deals with the

conditions of the gear box operation, and the design of the gear box based on easy

assembly and easy manufacturing at low cost.

The reverse gear on the manual transmission system typically uses an Idler gear

Idler gear is an intermediate gear which does not drive a shaft to perform any

work. Sometimes, a single idler gear is used to reverse the direction, in which case

it may be referred to as a reverse idler. In our system we are going to use the

compound idler gear. The input gear is connected with the crank shaft and output

gear is connected with the flywheel. During forward gear the input gear is directly

meshed with the output gear. If the input gear rotates in clockwise direction, the

output gear will rotate in anticlockwise direction. So the vehicle moves in the

forward direction. During reverse gear the idler gear is meshed in between the

input and output gear. Idler gear here using is a compound gear, so smaller gear in

compound gear is meshed with input gear and larger gear is meshed with output

gear. When the input gear rotates in clockwise direction the idler gear rotates in

anticlockwise direction. Also the output gear meshed with idler gear rotates in

13

clockwise direction. So the vehicle moves in reverse direction. The disadvantage is

that sometimes the chain gets loosened easily and need to maintain frequently.

2.4 ROADSTER CYCLE

Kenneth S. Keyes

Idosi publication in 2011

An improved three-speed or coaster bicycle having a driver bevel gear connected

to the pedals, a driven bevel gear at the hub of the rear wheel, one or more drive

shafts having beveled gears at each end and capable of transmitting the rotation of

the driver gear to the driven gear. This invention relates to coaster and three-speed

bicycles, and in particular, to bicycles having bevel gears and one or more drive

shafts that replace the traditional spur gears and chain.

14

Fig 2.3 Roadster Cycle

CHAPTER 3

COMPONENTS

3.1 BEVEL GEAR

Bevel gears are gears where the axes of the two shafts intersect and the tooth-

bearing faces of the gears themselves are conically shaped. Bevel gears are most

often mounted on shafts that are 90 degrees apart, but can be designed to work at

15

other angles as well. The pitch surface of bevel gears is a cone.

Fig 3.1 Bevel Gear

16

Fig3.2 Bevel Gear Terminology

3.1.1 INTRODUCTION

Two important concepts in gearing are pitch surface and pitch angle. The pitch

surface of a gear is the imaginary toothless surface that you would have by

averaging out the peaks and valleys of the individual teeth. The pitch surface of an

ordinary gear is the shape of a cylinder. The pitch angle of a gear is the angle

between the face of the pitch surface and the axis.

The most familiar kinds of bevel gears have pitch angles of less than 90 degrees

and therefore are cone-shaped. This type of bevel gear is called external because

the gear teeth point outward. The pitch surfaces of meshed external bevel gears are

coaxial with the gear shafts; the apexes of the two surfaces are at the point of

intersection of the shaft axes.

17

Bevel gears that have pitch angles of greater than ninety degrees have teeth that

point inward and are called internal bevel gears.

Bevel gears that have pitch angles of exactly 90 degrees have teeth that point

outward parallel with the axis and resemble the points on a crown. That's why this

type of bevel gear is called a crown gear. Miter gears are mating bevel gears with

equal numbers of teeth and with axes at right angles. Skew bevel gears are those

for which the corresponding crown gear has teeth that are straight and oblique.

Fig3.3 Milter and Its Mating Gear

3.1.2 TYPES

Bevel gears are classified in different types according to geometry:

Straight bevel gears have conical pitch surface and teeth are straight and

tapering towards apex.

Spiral bevel gears have curved teeth at an angle allowing tooth contact to be

gradual and smooth.

18

Fig 3.4 Spiral Gear

Zerol bevel gears are very similar to a bevel gear only exception is the teeth are

curved: the ends of each tooth are coplanar with the axis, but the middle of each

tooth is swept circumferentially around the gear. Zerol bevel gears can be

thought of as spiral bevel gears (which also have curved teeth) but with a spiral

angle of zero (so the ends of the teeth align with the axis).

Hypoid bevel gears are similar to spiral bevel but the pitch surfaces

are hyperbolic and not conical.

19

Fig 3.5 Double Helical Gear

3.1.3 GEOMETRY OF THE BEVEL GEAR

The cylindrical gear tooth profile corresponds to an involute, whereas the bevel

gear tooth profile is an octoid. All traditional bevel gear generators (such

as Gleason, Klingelnberg, Heidenreich & Harbeck, WMW Modul) manufacture

bevel gears with an octoidal tooth profile. IMPORTANT: For 5-axis milled bevel

gear sets it is important to choose the same calculation / layout like the

conventional manufacturing method. Simplified calculated bevel gears on the basis

of an equivalent cylindrical gear in normal section with an involute tooth form

show a deviant tooth form with reduced tooth strength by 10-28% without offset

20

and 45% with offset [Diss. Hünecke, TU Dresden]. Furthermore those "involute

bevel gear sets" causes more noise.

3.1.4 ADVANTAGES

This gear makes it possible to change the operating angle.

Differing of the number of teeth (effectively diameter) on each wheel

allows mechanical advantage to be changed. By increasing or decreasing the

ratio of teeth between the drive and driven wheels one may change the ratio of

rotations between the two, meaning that the rotational drive and torque of the

second wheel can be changed in relation to the first, with speed increasing and

torque decreasing, or speed decreasing and torque increasing.

3.1.5 DISADVANTAGES

One wheel of such gear is designed to work with its complementary wheel and

no other.

Must be precisely mounted.

The shafts' bearings must be capable of supporting significant forces.

3.2 SHAFT DRIVE

A drive shaft, driveshaft, driving shaft, propeller shaft (prop shaft), or Cardan

shaft is a mechanical component for transmitting torque and rotation, usually used

to connect other components of a drive train that cannot be connected directly

because of distance or the need to allow for relative movement between them.

As torque carriers, drive shafts are subject to torsion and shear stress, equivalent

to the difference between the input torque and the load. They must therefore be

21

strong enough to bear the stress, whilst avoiding too much additional weight as that

would in turn increase their inertia.

To allow for variations in the alignment and distance between the driving and

driven components, drive shafts frequently incorporate one or more universal

joints, jaw couplings, or rag joints, and sometimes a splined joint or prismatic joint.

Fig3.6 Exposed drive shaft on BMW's R32

Drive shafts have been used on motorcycles since before WW1, such as the

Belgian FN motorcycle from 1903 and the Stuart TurnerStellar motorcycle of

1912. As an alternative to chain and belt drives, drive shafts offer relatively

maintenance-free operation, long life and cleanliness. A disadvantage of shaft

drive on a motorcycle is that helical gearing, spiral bevel gearing or similar is

needed to turn the power 90° from the shaft to the rear wheel, losing some power

in the process. On the other hand, it is easier to protect the shaft linkages and drive

gears from dust, sand, and mud.

BMW has produced shaft drive motorcycles since 1923; and Moto Guzzi have

built shaft-drive V-twins since the 1960s. The British company, Triumph and the

major Japanese brands, Honda, Suzuki, Kawasaki and Yamaha, have produced

22

shaft drive motorcycles. All geared models of the Vespa scooter produced to date

have been shaft-drive. Vespa's automatic models, however, use a belt.

Motorcycle engines positioned such that the crankshaft is longitudinal and parallel

to the frame are often used for shaft-driven motorcycles. This requires only one

90° turn in power transmission, rather than two. Bikes from Moto Guzzi and

BMW, plus the Triumph Rocket III and Honda ST series all use this engine layout.

Motorcycles with shaft drive are subject to shaft effect where the chassis climbs

when power is applied. This effect, which is the opposite of that exhibited by

chain-drive motorcycles, is counteracted with systems such as BMW's Paralever,

Moto Guzzi's CARC and Kawasaki's Tetra Lever.

3.3 DC MOTOR

Fig 3.7 DC Motor with Worm Gear

A DC motor is any of a class of electrical machines that converts direct current

electrical power into mechanical power. The most common types rely on the forces

produced by magnetic fields. Nearly all types of DC motors have some internal

23

mechanism, either electromechanical or electronic; to periodically change the

direction of current flow in part of the motor. Most types produce rotary motion; a

linear motor directly produces force and motion in a straight line.

DC motors were the first type widely used, since they could be powered from

existing direct-current lighting power distribution systems. A DC motor's speed

can be controlled over a wide range, using either a variable supply voltage or by

changing the strength of current in its field windings. Small DC motors are used in

tools, toys, and appliances. The universal motor can operate on direct current but is

a lightweight motor used for portable power tools and appliances. Larger DC

motors are used in propulsion of electric vehicles, elevator and hoists, or in drives

for steel rolling mills. The advent of power electronics has made replacement of

DC motors with AC motors possible in many applications.

3.3.1 ELECTRO MAGNETIC MOTORS

A coil of wire with a current running through it generates

an electromagnetic field aligned with the center of the coil. The direction and

magnitude of the magnetic field produced by the coil can be changed with the

direction and magnitude of the current flowing through it.

A simple DC motor has a stationary set of magnets in the stator and

an armature with one more windings of insulated wire wrapped around a soft iron

core that concentrates the magnetic field. The windings usually have multiple turns

around the core, and in large motors there can be several parallel current paths. The

ends of the wire winding are connected to a commutator. The commutator allows

each armature coil to be energized in turn and connects the rotating coils with the

24

external power supply through brushes. (Brushless DC motors have electronics that

switch the DC current to each coil on and off and have no brushes.)

The total amount of current sent to the coil, the coil's size and what it's wrapped

around dictate the strength of the electromagnetic field created.

The sequence of turning a particular coil on or off dictates what direction the

effective electromagnetic fields are pointed. By turning on and off coils in

sequence a rotating magnetic field can be created. These rotating magnetic fields

interact with the magnetic fields of the magnets (permanent or electromagnets) in

the stationary part of the motor (stator) to create a force on the armature which

causes it to rotate. In some DC motor designs the stator fields use electromagnets

to create their magnetic fields which allow greater control over the motor.

At high power levels, DC motors are almost always cooled using forced

air.Different number of stator and armature fields as well as how they are

connected provide different inherent speed/torque regulation characteristics. The

speed of a DC motor can be controlled by changing the voltage applied to the

armature. The introduction of variable resistance in the armature circuit or field

circuit allowed speed control. Modern DC motors are often controlled by power

electronics systems which adjust the voltage by "chopping" the DC current into on

and off cycles which have an effective lower voltage.

Since the series-wound DC motor develops its highest torque at low speed, it is

often used in traction applications such as electric locomotives, and trams. The DC

motor was the mainstay of electric traction drives on both electric and diesel-

electric locomotives, street-cars/trams and diesel electric drilling rigs for many

years. The introduction of DC motors and an electrical grid system to run

machinery starting in the 1870s started a new second Industrial Revolution. DC

25

motors can operate directly from rechargeable batteries, providing the motive

power for the first electric vehicles and today's hybrid cars and electric cars as well

as driving a host of cordless tools. Today DC motors are still found in applications

as small as toys and disk drives, or in large sizes to operate steel rolling mills and

paper machines. Large DC motors with separately excited fields were generally

used with winder drives for mine hoists, for high torque as well as smooth speed

control using thyristor drives. These are now replaced with large AC motors with

variable frequency drives.

If external power is applied to a DC motor it acts as a DC generator, a dynamo.

This feature is used to slow down and recharge batteries on hybrid car and electric

cars or to return electricity back to the electric grid used on a street car or electric

powered train line when they slow down. This process is called regenerative

braking on hybrid and electric cars. In diesel electric locomotives they also use

their DC motors as generators to slow down but dissipate the energy in resistor

stacks. Newer designs are adding large battery packs to recapture some of this

energy.

3.4 COTTER JOINT

A cotter is a flat wedge shaped piece of rectangular cross section and its width

is tapered (either on one side or on both sides) from one end to another for an easy

adjustment. The taper varies from 1 in 48 to 1 in 24 and it may be increased up to 1

in 8, if a locking device is provided. The locking device may be taper pin or a set

screw used on the lower end of the cotter.

26

Fig 3.8 Cotter joint and its Components

The cotter is usually made of mild steel or wrought iron. A cotter joint is

temporary fastening and it is used to connect rigidly two co-axial rods or bars

which are subjected to axial tensile or compressive forces. It is usually used in

connecting a piston rod to crosshead of a reciprocating steam engine, a piston rod

and its extension as a tail or pump road, strap end of connecting rod etc.

3.4.1 TYPES OF COTTER JOINT

Following are the three commonly used cotter joints to connect two rods by a

cotter:

1. Socket and spigot cotter joint,

2. Sleeve and cotter joint,

3. Gibb and cotter joint.

27

3.4.1.1 SOCKET AND SPIGOT COTTER JOINT

In a socket and spigot cotter joint, one end of the rods (say A) is provided with a

socket type of end and the other end of the other rod(say B) is inserted into the

socket. The end of the rod which goes into a socket is also called spigot. A

rectangular hole is made in the socket and spigot. A cotter is then driven tightly

through a hole in order to make the temporary connection between the two rods.

The load is usually acting axially, but it changes its direction and hence the cotter

joint must be designed to carry both the tensile and compressive loads. The

compressive load is taken by the collar on the spigot.

Fig 3.9 Socket and Spigot Joint

3.4.1.2 SLEEVE AND COTTER JOINT

Sometimes, a sleeve and cotter joint is used to connect two round rods or bars.

In this type of joint, a sleeve or muff is used over the two rods and then two cotters

(one on each rod) are inserted in the holes provided for them in the sleeve and rods.

28

Fig 3.10 Sleeve and Cotter Joint

The taper of the cotter is usually 1 in 24. It may be noted that the taper sides of

the two cotters should face each other. The clearance is so adjusted that when the

cotters are driven in, the two rods come closer to each other thus making the joint

tight.

3.4.1.3 GIB AND COTTER JOINT

Fig3.11 Gib and Cotter Joint

29

A gib and cotter joint is usually used in strap end (or big end) of a connecting

rod. In such cases, when the cotter alone (i.e. without gib) is driven, the friction

between its ends and the inside of the slots in the strap tends to cause the sides of

the strap to spring open (or spread) outwards. In order to prevent this, gibs are used

which hold together at the ends of the stap. Moreover, gibs provide a larger bearing

surface for the cotter to slide on, due to the increased holding power. Thus, provide

a large bearing surface for the cotter to slide on, due to increased holding power.

Moreover, gibs provide a larger bearing surface for the cotter to slide on, due to the

increased holding power. Thus, the tendency of cotter to slacken back owing to

friction is considerably decreased. The jib, also, enables parallel holes to be used.

3.4.2 APPLICATIONS OF COTTER JOINT

1. Connection of the piston rod with the cross heads

2. Joining of tail rod with piston rod of a wet air pump

3. Foundation bolt

4. Connecting two halves of fly wheel (cotter and dowel arrangement).

3.4.3 COMPARISON BETWEEN KEY AND COTTER

1. Key is usually driven parallel to the axis of the shaft which is subjected to

torsion or twisting stress. Whereas cotter is normally driven at right angles to the

axis of the connected part which is subjected to tensile or compressive stress along

its axis.

2. A key resists shear over a longitudinal section whereas a cotter resist shear over

two transverse sections.

30

CHAPTER 4

OPERATIONS

4.1 LATHE

Fig 4.1 Lathe

  A machine tool which rotates the workpiece on its axis to perform various and

a lot of operations such as cutting, sanding, knurling, drilling, facing, turning, order

formation,  and a lot more with tools that are applied to the workpiece to create an

object which has symmetry about an axis of rotation.

Lathes are used in woodturning, metalworking, metal spinning, thermal

spraying, parts reclamation, and glass-working. Lathes can be used to shape

pottery, the best-known design being the potter's wheel. Most suitably equipped

metalworking lathes can also be used to produce most solids of revolution, plane

surfaces and screw threads or helices. Ornamental lathes can produce three-

dimensional solids of incredible complexity. The work piece is usually held in

place by either one or two centers, at least one of which can typically be moved

31

horizontally to accommodate varying work piece lengths. Other work-holding

methods include clamping the work about the axis of rotation using a chuck

or collet, or to a faceplate, using clamps or dogs.

Examples of objects that can be produced on a lathe

include candlestick holders, gun barrels, cue sticks, table legs, bowls, baseball bats,

musical instruments, crankshafts, and camshafts.

4.2 ARC WELDING

Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal

inert gas (MIG) welding or metal active gas (MAG) welding, is awelding process

in which an electric arc forms between a consumable wire electrode and the

workpiece metal(s), which heats the workpiece metal(s), causing them to melt, and

join. Along with the wire electrode, a shielding gas feeds through the welding gun,

which shields the process from contaminants in the air. The process can be semi-

automatic or automatic. A constant voltage, direct current power source is most

commonly used with GMAW, but constant current systems, as well as alternating

current, can be used.

There are four primary methods of metal transfer in GMAW, called globular,

short-circuiting, spray, and pulsed-spray, each of which has distinct properties and

corresponding advantages and limitations.

Originally developed for welding aluminum and other non-ferrous materials

in the 1940s, GMAW was soon applied to steels because it provided faster welding

time compared to other welding processes. The cost of inert gas limited its use in

steels until several years later, when the use of semi-inert gases such as carbon

dioxide became common. Further developments during the 1950s and 1960s gave

the process more versatility and as a result, it became a highly used industrial

32

process. Today, GMAW is the most common industrial welding process, preferred

for its versatility, speed and the relative ease of adapting the process to robotic

automation.

Fig 4.2 Arc Welding

Unlike welding processes that do not employ a shielding gas, such as shielded

metal arc welding, it is rarely used outdoors or in other areas of air volatility. A

related process, flux cored arc welding, often does not use a shielding gas, but

instead employs an electrode wire that is hollow and filled with flux.

For most of its applications gas metal arc welding is a fairly simple welding

process to learn requiring no more than a week or two to master basic welding

technique. Even when welding is performed by well-trained operators weld quality

can fluctuate since it depends on a number of external factors. All GMAW is

dangerous, though perhaps less so than some other welding methods, such

as shielded metal arc welding.

33

4.2.1 OPERATION

The basic technique for GMAW is quite simple, since the electrode is fed

automatically through the torch (head of tip). By contrast, in gas tungsten arc

welding, the welder must handle a welding torch in one hand and a separate filler

wire in the other, and in shielded metal arc welding, the operator must frequently

chip off slag and change welding electrodes. GMAW requires only that the

operator guide the welding gun with proper position and orientation along the area

being welded. Keeping a consistent contact tip-to-work distance (the stick

out distance) is important, because a long stick out distance can cause the electrode

to overheat and also wastes shielding gas. Stick out distance varies for different

GMAW weld processes and applications. The orientation of the gun is also

important—it should be held so as to bisect the angle between the workpieces; that

is, at 45 degrees for a fillet weld and 90 degrees for welding a flat surface. The

travel angle, or lead angle, is the angle of the torch with respect to the direction of

travel, and it should generally remain approximately vertical. However, the

desirable angle changes somewhat depending on the type of shielding gas used—

with pure inert gases; the bottom of the torch is often slightly in front of the upper

section, while the opposite is true when the welding atmosphere is carbon dioxide.

4.3 CYLINDRICAL GRINDING MACHINE

The cylindrical grinder is a type of grinding machine used to shape the outside

of an object. The cylindrical grinder can work on a variety of shapes; however the

object must have a central axis of rotation. This includes but is not limited to such

shapes as a cylinder, an ellipse, a cam, or a crankshaft.

34

Fig 4.3 Cylindrical Grinding Machine

Cylindrical grinding is defined as having four essential actions:

1. The work (object) must be constantly rotating

2. The grinding wheel must be constantly rotating

3. The grinding wheel is fed towards and away from the work

4. Either the work or the grinding wheel is traversed with respect to the other.

4.3.1 APPLICATION

The cylindrical grinder is responsible for a plethora of innovations and

inventions in the progression of science and technology. Any situation in which

extremely precise metalworking is required, the cylindrical grinder is able to

provide a level of precision unlike any other machine tool. From the automotive

industry to military applications, the benefits the cylindrical grinder has given us

are immeasurable.

35

4.4 BROACHING

Broaching is a machining process that uses a toothed tool, called a broach, to

remove material. There are two main types of broaching: linear androtary. In linear

broaching, which is the more common process, the broach is run linearly against a

surface of the workpiece to effect the cut. Linear broaches are used in a broaching

machine, which is also sometimes shortened to broach. In rotary broaching, the

broach is rotated and pressed into the workpiece to cut an axis symmetric shape. A

rotary broach is used in a lathe or screw machine. In both processes the cut is

performed in one pass of the broach, which makes it very efficient.

Broaching is used when precision machining is required, especially for odd

shapes. Commonly machined surfaces include circular and non-circular

holes, splines, keyways, and flat surfaces. Typical workpieces include small to

medium-sized castings, forgings, screw machine parts, and stampings. Even

though broaches can be expensive, broaching is usually favored over other

processes when used for high-quantity production runs.

Broaches are shaped similar to a saw, except the height of the teeth increases

over the length of the tool. Moreover, the broach contains three distinct sections:

one for roughing, another for semi-finishing, and the final one for finishing.

Broaching is an unusual machining process because it has the feed built into the

tool. The profile of the machined surface is always the inverse of the profile of the

broach. The rise per tooth (RPT), also known as the step or feed per tooth,

determines the amount of material removed and the size of the chip. The broach

can be moved relative to the workpiece or vice versa. Because all of the features

are built into the broach no complex motion or skilled labor is required to use it.  A

broach is effectively a collection of single-point cutting tools arrayed in sequence,

cutting one after the other; its cut is analogous to multiple passes of a shaper.

36

4.4.1 PROCESS

The process depends on the type of broaching being performed. Surface

broaching is very simple as either the workpiece is moved against a stationary

surface broach, or the workpiece is held stationary while the broach is moved

against it.

Internal broaching is more involved. The process begins by clamping the

workpiece into a special holding fixture, called a workholder, which mounts in the

broaching machine. The broaching machine elevator, which is the part of the

machine that moves the broach above the workholder, then lowers the broach

through the workpiece. Once through, the broaching machine'spuller, essentially a

hook, grabs the pilot of the broach. The elevator then releases the top of the pilot

and the puller pulls the broach through the workpiece completely. The workpiece

is then removed from the machine and the broach is raised back up to reengage

with the elevator. The broach usually only moves linearly, but sometimes it is also

rotated to create a spiral spline or gun-barrel rifling.

Cutting fluids are used for three reasons;

1. to cool the work piece and broach

2. to lubricate cutting surfaces

3. to flush the chips from the teeth.

Fortified petroleum cutting fluids are the most common, however heavy duty

water soluble cutting fluids are being used because of their superior cooling,

cleanliness, and non-flammability.

37

4.4.2 USAGE

Broaching was developed for machining internal keyways. However, it was

soon discovered that broaching is very useful for machining other surfaces and

shapes for high volume work pieces. Because each broach is specialized to cut just

one shape either the broach must be specially designed for the geometry of the

work piece or the work piece must be designed around standard broach geometry.

A customized broach is usually only viable with high volume work pieces, because

the broach can cost Rs.75,000 to Rs.150,000 to produce.

Broaching speeds vary from 20 to 120 surface feet per minute (SFPM). This

results in a complete cycle time of 5 to 30 seconds. Most of the time is consumed

by the return stroke, broach handling, and work piece loading and unloading.

The only limitations on broaching are that there are no obstructions over the

length of the surface to be machined, the geometry to be cut does not have curves

in multiple planes, and that the work piece is strong enough to withstand the forces

involved. Specifically for internal broaching a hole must first exist in the work

piece so the broach can enter.

Broaching works best on softer materials, such as brass, bronze, copper

alloys, aluminium, graphite, hard rubbers, wood, composites, and plastic.

However, it still has a good machinability rating on mild steels and free machining

steels. Broaching is more difficult on harder materials, stainless steel and titanium,

but is still possible.

38

CHAPTER 5

CONSTRUCTION AND WORKING

5.1 WORK METHODOLGY

A steel frame is used for holding purpose. Five Bevel gears are used having 23

teeth each and hence their ratio as 1:1. A 12V DC motor having 80 rpm is

connected with a bevel gear 1 using shaft. Bevel gear 2 is engaged with the bevel

gear 1. On the other side, a two wheeler’s rear wheel is taken along with its bush

and hub assembled. A cotter joint is fixed in wheel hub using shaft which is itself

connected to two bevel gears 3 and 4 opposite to each other which is connected.

.

Fig 5.1 Project in Top View in PRO-E Model

Another bevel gear 5 is adjacently placed with two oppositely placed bevel

gears 3 and 4 as shown in the figure. Bevel gear 2 and 5 are connected using shaft.

A lever is placed in between two bevel gears 3 and 4 which are in oppositely faced

in order for engage and disengage purpose. These things are joined with the help of

arc welding. A lead acid battery of 7.5 amps is connected to the motor using wires

and switches for running purpose.

39

Fig 5.2 Model In PRO-E

Fig 5.3 Project Fabrication

40

5.2 WORKING

When switch is ON then the motor starts running so bevel gears 1, 2, 5 also

simultaneously running.

5.2.1 REVERSE DIRECTION

Fig 5.4 Lever when shifted right

When the lever is moved to the right direction then bevel gear 5 and 3 are

engaged and bevel gear 5 and 4 are disengaged. As bevel gear 5 is rotating in anti-

clockwise direction, gear 3 rotates in clockwise direction as shown in the figure

and thus the rear wheel move in reverse direction. Thus for a rider if he wants to

move in reverse direction he should move the lever into right direction.

5.2.2 FORWARD DIRECTION

When the lever is moved to the left direction then bevel gear 5 and 4 are

engaged and bevel gear 5 and 3 are disengaged.

41

Fig 5.5 Lever when shifted left

As bevel gear 5 is rotating in anti clockwise direction, gear 4 also rotates in anti

clockwise direction as shown in the figure and thus rear wheel move in forward

direction.

5.3 DESIGN CALCULATIONS

Speed = 80 rpm

Shaft diameter = 15mm

Gear inner diameter = 50 mm

Outer diameter =80mm

No. of teeth= 23

Breadth = 18mm

Power = 0.25 hp motor =186.5watts

Diameter of pinion = 80 mm

42

1. Design of the shaft

Torque acting on the pinion T= p*60/ (2πNp) N-m

= 186.5*60/ (2*3.14*80)

= 22.26 N-m

Slant height of the pitch cone L = √((DG/ 2)2 + (Dp/ 2)2)

= √(2(80/2)2)

=56.57 mm

Mean radius Rm = (L- b/2)(Dp/ 2L)

= (56.57-18/2)(80/(2*56.57))

= 33.636 mm

Tangential force acting at the mean radius of the pinion is

WT = T/ Rm

= 22.26/ 33.636 * 103

= 661.91 N

The axial force acting on the pinion is

WRH = WT tanϕ * sinθp1

= 661.91 * tan 14.5 * sin 45

= 121.04 N

The radial force acting on the pinion is

WRV = WT * tanϕ * cosθp1

43

= 661.91 * tan 14.5 * sin 45

= 121.04 N

The bending moment due to WRH and WRV is given by

M1 = WRV – WRH * RM

= 121.04 – 121.04 * 33.636

= 3950.38 N mm

The bending moment due to tangential force WT is given by

M2 = WT = 121.04 N mm

Resultant bending moment is

M = √((M1)2 + (M2)2)

= √ ((3950.38)2 + (121.04)2 )

= 3952.23 N mm

Equivalent twisting moment is

Te = √ (M2 + T2)

= √ ((3952.23)2 + (22.26 * 103)2)

= 22608.13 N mm

But diameter of pinion dp = 15 mm

Shear stress of the pinion is given by

τ = ( Te * 16) / ( π * 153)

= 34.16 N/ mm2

44

2.Maximum load applied in cotter joint

Diameter of the shaft d = 15 mm

Tensile stress σt = 50 N / mm2

Maximum load applied will be

P = π / 4 * d2 * σt

= 3.14 / 4 * 152 *50

= 8835.72 N

3. Increase in weight

Percentage in increase in weight will be

% W = (actual weight – original weight) / actual weight * 100

= (10 – 9.7) / 10 *100

= 3 %

45

CHAPTER 6

CONCLUSION

The importance of engaging a reverse gear mechanism would help to reduce

human effort and be a boon to the upcoming future engineering society. The

replacement of the COMET GEAR BOX by the innovative bevel gear position in

the shaft driven bikes has saved more than FIFTEEN THOUSAND in case of

Indian money today for engaging reverse gear mechanism. This reverse

mechanism in shaft driven bikes are very useful to handicapped people in terms of

short legs, low powered people and mostly for women who are craze towards the

bike. Thus using reverse gear mechanism in future there wouldn’t be problem for

people to have a back drive in situations of:

1. Public parking

2. Struck in trench

3. Mashed up in heavy traffic

4. Reduce human burden by reducing totally human power usage.

The increase in weight is also minimum so there won’t be any static balance

problem. In future, this method can be brought to normal usage so that normal

people and physically challenged people will have ease of work while reversing.

46

CHAPTER 7

REFERENCE

1. Automobile Engineering, R.B. Gupta, 4 editions, 2006.

2. Over Drive magazine, December edition, 2004.

3. www.wikipedia.com

4. www.howstuffworks.com

5. Gopalkrishnan, K., J. Sundeep Aanad and R. Udayakumar, 2013. Structural

Properties Doped azopolyester and its characteristics, Middle-East Journal of

Scientific Research, ISSN:1990-9233, 15(12): 1773-1778.

6. Gopalakrishnan, K., M. Prem Jeya Kumar, J. Sundeep Aanand and R.

Udayakumar, 2013. Thermal Properties of Doped Azopolyester and its

Application, Indian Journal of Science and Technology, ISSN: 0974-6846, 6(6):

4722-4725.

47

48