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
SIGNATURE
Mr.A.SRITHAR,M.E.,
Mr. M.MAREESWARAN, M.E.,
HEAD OF THE DEPARTMENT
SUPERVISOR, ASST. PROFESSOR,
Department of Mechanical Engineering Department of Mechanical Engineering
Sri Sai Ram Institute of Technology
Sri Sai Ram Institute of Technology
Chennai – 600044
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
TITLE
PAGE NO.
NO.
1.
ACKNOWLEDGEMENT
iii
ABSTRACT
iv
LIST OF FIGURES
viii
INTRODUCTION
1
1.1 HISTORY OF BICYCLES
1
1.2 REVERSE DRIVEN BICYCLE
2
1.3 CHAIN DRIVEN BIKES
3
1.3.1 HISTORY
2.
4
1.4 SHAFT DRIVEN BIKES
5
1.5 REVERSE GEAR IN BIKE
9
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
2.3 DEVELOPMENT AND IMPLENTATION
12
13
OF REVERSE GEAR MECHANISM IN
BIKE
2.4 ROADSTER CYCLE
v
14
CHAPTER
TITLE
PAGE NO.
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
3.4 COTTER JOINT
23
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
TITLE
PAGE NO.
NO.
4
OPERATION
30
4.1 LATHE
30
4.2 ARC WELDING
31
4.2.1 OPERATION
4.3 CYLINDRICAL GRINDING MACHINE
4.3.1 APPLICATIONS
4.4 BROACHING
5
31
33
34
35
4.4.1 PROCESS
36
4.4.2 USAGE
37
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
viii
FIG NO.
CAPTION
PAGE
NO.
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, chaindriven 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
"cycle". In Unicode,
bicycle
include "bike", "pushbike", "pedal
the hexadecimal code
for
"bicycle"
cycle", or
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 SturmeyArcher.
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 SturmeyArcher.
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 (nonsporting) models.
Chain
drive
was
the
main
feature
which
differentiated
the safety
bicycle introduced in 1885, with its two equal-sized wheels, from the directdrive 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.
Fig 2.2 Shaft Driven Bike Components
12
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
clockwise direction. So the vehicle moves in reverse direction. The disadvantage is
that sometimes the chain gets loosened easily and need to maintain frequently.
13
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.
Fig 2.3 Roadster Cycle
14
CHAPTER 3
COMPONENTS
3.1 BEVEL GEAR
Bevel gears are gears where the axes of the two shafts intersect and the toothbearing 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
other angles as well. The pitch surface of bevel gears is a cone.
Fig 3.1 Bevel Gear
15
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.
16
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.
17
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.
18
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
19
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
20
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
21
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
22
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
23
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 dieselelectric 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
24
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.
25
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.
26
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.
27
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
28
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.
29
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 threedimensional 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
30
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 semiautomatic 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
31
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.
32
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.
33
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.
34
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.
35
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.
36
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.
37
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.
38
Fig 5.2 Model In PRO-E
Fig 5.3 Project Fabrication
39
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 anticlockwise 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.
40
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
41
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
42
= 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
43
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%
44
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.
45
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.
46
47