Acknowledgement

First and foremost we would like to say thank you from bottom of our heart to our God
who gives us this chance to success this project from beginning up to end of this project.
Also we would like to thank our beloved advisor Wasihun Wondimu that he gave us
different direction to do our project.

Thirdly we would like to thank our group members to their contribution in all preparation
of this project and we have great thanks for all Mechanical Engineering students. Finally
we would like to express our heartfelt gratitude to GOOGLE for helping us to recognize
different ideas for our project.

i
 Abstract

The aim of this project is to connect two shafts using coupling system which is bushed
pin coupling that able to transmit torque .In this project, Design of bushed pin coupling
by using the standard equation for design and applying 163 Nm of torque for testing
purposes to find the main deformation in the couplings thus trying to design each
components of the bushed pin coupling in detail and Assembling and drawing of each
parts using Solid works and AutoCAD. All the automobile vehicles available are always
set to changing speed and torque between engine and driving wheels. This project mainly
focuses on the design of a bushed pin that can transmit torque.

ii
 List of Figures

Figure 3.1………………………………………………………………………………….16

Figure 3.2……………………………………………………………………………………17

Figure 3.3…………………………………………………………………………………….19

Figure 3.4……………………………………………………………………………………21

iii
 List of symbol

Π pi(3.14)

𝜹 deflection

A area

DO outer diameter

Di inner diameter

dp pitch diameter

d n nominal diameter

L length

T totque

t thickness

N speed in rpm

ρ density

m mass

v volume

p power

w width

iv
 List of table

Table 2.1………………………………………………………………………….7

Table 2.2 …………………………………………………………………………8

Table 2.3……………………………………………………………………………9

Table 2.4…………………………………………………………………………....10

Table 2.5………………………………………………………………………….....12

Table 2.6…………………………………………………………………………….13

Table 2.7…………………………………………………………………………….14

Table 3.1……………………………………………………………………………..19

v
 Table of Contents

Contents
page

Acknowledgement …………………………………………………………………………………
ꜞ

Abstract …………………………………………………………………………………………ꜞꜞ

List of Figures……………………………………………………………………………………ꜞꜞꜞ

List of symbol………………………………………………………………………….…………ꜞⱽ

List of table……………………………………………………………………………………….ⱽ

CHAPTER ONE …………………………………………………………………………… ….1

1. Introduction…………………………………………………………………………………....1

1.1. Background of the Study………………………………………………………………….1

1.2. Statement of the Problem ……………………………………………………..…………1

1.3. Objectives ………………………………………………………………………………….. 1

1.3.1. General Objectives………………………………………………………………………..2

1.3.2. Specific Objectives ………………………………………………………….………….2

1.4. Scope and Limitations of the Project………………………………………….….……2.

1.5. Significance of the Project………………………………………………….……….….3

CHAPTER TWO ………………………………………………………………….…….….… 4

3 2. Literature Review ………………………………………………………………….…… 4
CHAPTER THREE ……………………………………………………………………………16
3. Geometric Analysis…………………………………………………………………………16

3.1. Methodology……………………………………………………………………………….16

CHAPTER FOUR ……………………………………………………………………………….23

4. Result and Discussion……………………………………………………………………..…23

4.1.Cost Analysis ……………………………………………………………………………….25

CHAPTER FIVE…………................................................................................................28

vi
5.1. Conclusion …………………………………………………………………………………28

5.2. Recommendation………………………………………………………………………29

REFERENCES ……………………………………………………………………………… 30

vii
 HAPTER ONE

INTRODUCTION

1.1 Background of the Study

The invention of pin and bush coupling was stated by renold in 1920 in Canada .wich
deals that as the pin and bush design is ideal for application s that involves safty such as
elevator drives or fire pumps. the elastomer elements reduce vibration and dampen
impact loads, as well as accommodate misalignment up 0.5 degrees.

Renold also manufactures many custom variations of this coupling including brake drum
and shear pin type couplings.

Later in 1849 lenged invented safty pin .[1]

1.2 Statement of the Problem

The reason why we design bushed pin coupling is because of it is too much needed when
shafts are to be connect each other without any misalignment. most type of coupling like
Oldham and universal coupling needs high installation and high maintenance als o are
more costly but bushed pin is a easy to assemble with short period of time and is
less costly. Any activities all over the worlds does not need any power disputation
that’s why this project stands to figurout this type of problem.

1.3 Objectives

1.3.1 General Objectives

The general objective of this project is to design a bushed pin coupling.

1.3.2 Specific Objectives

The specific objectives of this project are

 To design hub
 To design key
 To design bolt
 To design flange

1.4 Scope and Limitations of the Project

The scope of this project is design of bushed pin coupling starting from the proper
way of material selection for each component of the bushed pin, stress and failure
viii
 analysis on , determination of clutch parameters (like:- mean radius disc clutch
,mean diameter of spring, pitch of the coil etc.. ),determinations of key parametr ,
proper way of bearing selection, result and discussion of the whole material
design, cost analysis up to the assembly modeling. Designing of the single plate
clutch with the driven (output) power of 50 KW for with the speed of 2000
R.P.M. Used in automotive vehicle.

The project only deals up to the designing of a single plate clutch, but not manufacturing
of it and this is considered as a limitation on this project. Also while we design our
project internet connection was one problem. There is no

1.5 Significance of the Project

As coupling is a device used to connect two shafts together at the end. This project is
also able to figure out the problems on which the shocks, vibration and misalignment
formed when shafts connect.

Bushed pin coupling is used to transmit high torque. specially when the torques needs to
be maximize to the needed point. When shafts connected by coupling there is also wear
formation and heat absorption .so bushed pin is able to modify this type of proplem.

ix
CHAPTER TWO

Literature Review
2.1 Introductions

Main components of bushed pin coupling are:

 Hub
 Key
 Flange
 Stud Bolt

Hub:- –is the central part of the wheel that connect the axle to the wheel is self. The hub
is designed as a hollow shaft, for the maximum torque transmitted. We know that the
maximum torque transmitted.[3]

Key:- are machine elements used to prevent relative rotational movement between a shaft
and the parts mounted on it, such as pulleys, gears, wheels, couplings, etc..[4]

Flange: a part of coupling which is tightened by stud bolt that used top connect shafts.

Stud Bolt:-stud bolts for flange consists of a fully threaded steel rod and two heavy
hexagonal steel nuts. Are inserted in the flanges holes and tightened to seal a flanged
joint .the numbe ,the length ,for flanged connection depend on the flanges type ,diameter,
and rating (as per the ASME flange bolt chart). [2]

^S.balestra ( September 2017).”project materials ”.lugano swizerland.

https//blog.project material.com/flange/flange material/.

Materials for Pipe Flanges (ASTM)

The most common materials for pipe flanges (forged grades) are: ASTM A105 (carbon
steel high temperature to match A53/A106/API 5L pipes), A350 Grades LF1/2/3 (carbon
steel low temperature to match A333 pipes), A694 Grades F42 to F80 (high yield carbon
steel to match API 5L pipe grades), ASTM A182 Grades F5 to F91 (alloy steel flanges to
match A335 pipes), A182 Grade F304/316 (stainless steel flanges to match A312 SS
pipes), A182 Gr. F44/F51/F53/F55 (duplex and super duplex to match A790/A928 pipes)
and various nickel alloy grades (Inconel, Incoloy, Hastelloy, Monel).

x
CARBON STEEL FLANGES

The chemical composition and the mechanical properties of the three main carbon steel
flanges material grades:

ASTM A105 (high-temperature carbon steel) to match A53, A106, API 5L carbon steel
pipes

ASTM A350 LF1, LF2, LF3 (low-temperature carbon steel) to match ASTM A333 pipes

ASTM A694 F42, F52, F60, F65 (high-yield carbon steel to match API 5L X42, X52,
X60, and X65 steel pipes

MECHANICAL PROPERTIES A105, A350, A694

ASTM A105 (High-temperature carbon steel flange material)

Property ASTM A105 ASTM A350-LF2

Tensile Strength Min, psi 70,000 70,000-95,000

Tensile Strength Min, N/mm² 485 485-655

Yield Strength Min, psi 36,000 36,000

Yield Strength Min, N/mm² 250 250

Elongation (%) 22 22

Reduction of Area (%) 30 30

ALLOY STEEL FLANGES

Alloy flange materials (chrome-moly) have higher chrome and molybdenum content than
carbon steel flanges. Alloy steel flange materials suit high temperature and high-pressure
applications and improved resistance to corrosion when compared to regular carbon steel
flanges grades.

Alloy Steel Flange Materials

alloy steel flanges ASTM A182

xi
ASTM A182 alloy flanges are extremely ductile, strong and tough and easy to weld and
offer oxidation and scaling resistance. These grades match with ASTM A335 alloy steel
pipes.

MECHANICAL PROPERTIES A182

ELEMENT & PROPERTIES LOW ALLOY STEEL MEDIUM ALLOY STEEL

F11 CL2 F22 CL3 F5 F9

TENSILE STRENGTH PSI (MPA) 70,000 (485) 75,000 (515) 70,000 (485) 85,000
(585)

YIELD STRENGTH PSI MIN 40,000 (275) 45,000 (310) 40,000 (275) 55,000
(380)

ELONGATION 2” % MIN 20 20 20 20

REDUCTION AREA % MIN 30 30 35 40

HARDNESS (HB) MAX* 143 ~ 207 156 ~ 207 143 ~ 217 179 ~ 217

STAINLESS STEEL FLANGES

The key elements that differentiate stainless steel materials for flanges, compared to other
grades, are the Nickel (Ni), Chrome (Cr), and Molybdenum content (Mo). The price for
these metals fluctuates daily on the London Metal Exchange (Nickel, Moly) and on the
ferroalloy market (ferrochrome).

LME price for Nickel (USD per tonne)

LME price for Molybdenum (USD per tonne)

LME price for Copper (USD per tonne)

Ferrochrome market price (USD per kg.)

Stainless Steel Flange Materials ASTM A182

Stainless steel flanges ASTM A182

xii
Table 2.1 MECHANICAL PROPERTIES A182 F304/F

DUPLEX FLANGES

Duplex steel (ASTM A182 2205) is an extremely corrosion resistant, work hardenable
stainless steel, whose microstructure consists of a mixture of austenite and ferrite phases.

Duplex Flange ASTM A182 UNS S31803 UNS S32205

Due to this particular chemical and physical composition, duplex stainless steel UNS
S31803 features the properties characteristic of both types of stainless steel materials
(ferritic and austenitic).Generally speaking, duplex stainless steel is way tougher than
ferritic stainless steels, has a superior strength than austenitic steels (series 300 and 400)
and has superior resistance to corrosion when compared to SS304 and SS316 (high
intragranular corrosion, also in chloride and sulfide environments). Whilst austenitic
stainless steels are non-magnetic, duplex stainless steel shows magnetic properties.Duplex and
super duplex flanges match with ASTM A790 seam

xiii
Table 2.2 MECHANICAL PROPERTIES A182 DUPLEX AND SUPER DUPLEX

Mechanical Properties Duplex 2205 Super Duplex

(ASTM A182 UNS S31803 – ASTM A182 UNS S32750 –
UNS S32205) 32760)

Tensile Strength (in MPa) 620 770

Proof Stress 0.2% (in MPa) 450 550

A5 Elongation (in %) 25 25

NICKEL ALLOY FLANGES

ASTM SPECIFICATIONS FOR NICKEL ALLOY FLANGES

ASTM B160 Nickel 200 Flange

ASTM B166 Inconel 600 Flange

ASTM B564 Inconel 625 Flange

ASTM B425 Incoloy 800 Flange

ASTM B564 Incoloy 825 Flange

ASTM B564 Monel K400 Flange

ASTM B564 Hastelloy C276 Flange

xiv
Table 2.3 : MECHANICAL PROPERTIES NICKEL-ALLOY FLANGES

Superalloy Yield Tensile Elongation Brinell

grade Strength (in Strength (in %
ksi) ksi)
Nickel 200 15 55 35 90-120

Nickel 201 12 50 35 90-120

Monel 400 25 70 35 110-149
Monel K- 100 140 17 265-346
500
Hastelloy B- 51 110 40 -
2
Hastelloy D- 49 114 57 -
205 –
Inconel 600 30 80 30 120-184

From all materials used for flanges steel (stainless steel) is the best through all characteristics.

^S.balestra ( September 2017).”project materials ”.lugano swizerland.

https//blog.project material.com/bolt/bolt material/.

STUD BOLT MATERIALS

The most common materials for stud bolts in flanges are alloy steel ASTM A193 (grade
B7, B8, B8M, B8T), ASTM A453 (grade 660), ASTM A320 (grade L7, L7M), and
ASTM A182 (duplex and super duplex bolting). For aggressive fluids and environments,
stud bolts can be coated with Xylan, Xylar and other materials.

ASTM A193 STUD BOLTS (HIGH-TEMP.)

The ASTM A193 specification covers alloy-steel and stainless steel stud bolts materials
for high temperature or high-pressure service.

ASTM A193 stud bolts are available in national coarse (UNC) thread pitches, generally
used in traditional applications, which means that there are 8 threads per inch (“thread per

xv
inch”) for rod diameters above 1 inch. B7 is the most common specification grade for
stud bolts.

stud bolt materials

The most common stud bolts materials covered by ASTM A193 are:

ASTM A193 B5

ASTM A193 B6

ASTM A193 B7: Alloy steel, AISI 4140/4142 quenched and tempered

ASTM A193 B7M

ASTM A193 B16

ASTM A193 B8: Class 1 Stainless steel, AISI 304, carbide solution treated.

ASTM A193 B8A

ASTM A193 B8M: Class 1 Stainless steel, AISI 316, carbide solution treated.

ASTM A193 B8MA

ASTM A193 B8T (SS 321)

ASTM A193 B8cl2: Class 2 Stainless steel, AISI 304, carbide solution treated, strain
hardened

ASTM A193 B8Tcl2

ASTM A193 B8Mcl2: Class 2 Stainless steel, AISI 316, carbide solution treated, strain
hardened.

Table 2.4:mechanical properties of d/t type of steel

ASTM A193 Tensile Strength, in k Yield Strength, in ksi Elongation in%

ksi
ASTM A193 B7 125 105 16
ASTM A193 B8: 115 95 16
Class 1
ASTM A193 B8M: 75 75 18
Class 1
ASTM A193 grade 75 30 30
B8class2

xvi
Based on different classification stud bolt material with their identity characteristics and
specified in detail from the table above it is clear that steel ASTM A193 grade B8MA Is
preferable one.

Basavaraj Sajjan.(2016),” Adithya Parthasarathy Product Design and Development of

Wheel Hub for an All-Terrain Vehicle (ATV)” , Karnataka, India.

Material Property

There are a lot of materials used for hub which they have high strength , stiffness good
heat and corrosion resistances properties. Here the two materials used for the wheel hub
Aluminum 6061 T6 and EN8 Mild Steel are compared. The properties of the materials
are mentioned below:

Aluminum 6061 T6

 Density: 2.7 g/cm3

 Brinell Hardness number: 95 BHN
 Rockwell Hardness number: 40 Ra
 Ultimate Tensile Strength: 310 MPa
 Tensile Yield Strength: 276 MPa
 Modulus of Elasticity : 68.9 GPa
 Poisson’s ratio: 0.33
 Fatigue Strength: 96.5 MPa
 Melting Point: 582 - 652°C
 Specific Heat Capacity: 0.896 J/g-°C)

EN8 Mild Steel

 Density: 7.85 g/cm3

 Brinell Hardness number: 201 BHN
 Rockwell Hardness number: 93 Ra
 Ultimate Tensile Strength: 620 -740MPa
 Tensile Yield Strength: 415MPa
 Modulus of Elasticity : 190-210 G Pa
 Poisson’s ratio: 0.27-0.30
 Melting Point: approx. 1500°C
 Thermal conductivity: 50.7 W/m K

Based on properties they adapt EN8 Mild Steel is best material for hub.

Essays , UK. (November 2018). Material Selection For shaft Engineering Essay

We compared three materials for the selection material of key.

xvii
  Aluminum alloy
 Stainless steel
 Carbon steel

Aluminum alloy: Aluminum Alloy is a medium to high strength heat treated alloy with
higher strength than 6005A. It is commonly used for heavy-duty structure in the railway
coach, truck frames, shipbuilding, and bridges the military, aerospace applications
including helicopter rotor shell, tubes, pylons and towers, transportation, boiler making,
motorboats and rivets.

Grade 6061-T6

It has very good corrosion resistance and excellent weld ability although reduced strength
in the weld zone. It has medium fatigue strength. It has good cold formability in temper
T4, but limited in temper T6. Not suitable for very complex cross parts.

Table 2.5: property of aluminum alloy Grade 6061 – T6

ISO standard AA 6061 – T6

Tensile Yield strength (M pa) 310
Shear Strength (M pa) 190
Proof Stress (M pa) 270
Elongation over 50mm (%) 12
Hardness Vickers (HV) 100
Density(kg/m3) 2700
Thermal Conductivity (W/m k) 166
Melting point (0c) 650
Electrical Resistivity 0.040

Stainless steel: Stainless steel is also known as grades 304 and 304L respectively.
Stainless steel 304 is the most versatile and widely used. Type 304 stainless steel are
austenitic grades can be severely deep drawn. This property has led 304 became the
dominant grade used in applications such as sink and cook.

Grade 304

Type grade304 stainless steel is an austenitic grade that can be severely deep drawn. This
property has resulted in 304 being the dominant grade used in applications like sinks and
saucepans and has excellent corrosion resistance in many environments and when in
contact with different corrosive media. Pitting and crevice corrosion can occur in
environments containing chloride. Pressure corrosion cracking can occur above 60°C.

xviii
Table 2.6: property for stainless steel Grade 304

ISO standard BS 970 Grade 304

Tensile Yield strength (Mpa) 520-720
Compressive Strength (Mpa) 210
Proof Stress (Mpa) 210
Elongation over 50mm (%) 45
Modulus of Elasticity (Gpa) 193
Density (kg/m3) 7780
Thermal Conductivity (W/mk) 16.2
Melting point (0c) 1450
Electrical Resistivity 0.072

Carbon steel: Steel is a metal alloy consisting mainly of iron and contains 0.2 to 2.1
percent carbon. All steel contains carbon, but the term “carbon steel” applies specifically
to steel containing carbon as the main alloying constituents. Medium carbon steel is
carbon steel that contains between 0.30 and 0.60 percent carbon. It also has a manganese
content of between 0.6 and 1.65 percent. This type of steel provides a good balance
between strength and ductility, and it is common in many kinds of steel parts.

Grade 080M30

It can provide a better combination of toughness, strength and hardness. It also provides a
counterbalance weight during for low-oscillation rotary process. Despite its relatively
limited corrosion resistance, carbon steel is used in large tonnages in marine applications,
fossil fuel power and nuclear power plants, transportation, chemical processing,
petroleum production and refining, pipelines, mining, construction and metal - processing
equipment.

Table 2.7 : Property for Medium Carbon Steel Grade 080M30

ISO standard BS970 080M30

Tensile Yield strength (M pa) 550
Ultimate Tensile Strength (M pa) 930
Elongation over 50mm (%) 269
Young’s Modulus (G pa) 16
Density (kg/m3) 205
Thermal Conductivity (W/m k) 7820
Specific heat capacity (J/g-0c) 46.6
Electrical Resistivity 0.475
Hardness (HB) 234

xix
table 2.8:Final selection of material based on design and material specification

ISO Tensile Elongation Density Thermal Electrical Price per

standard Yield over kg/m3 Conductivity Resistivity ton
strength 50mm (%) (W/mk) (USD)
(Mpa)
Aluminum 310 12 2700 166 0.040 2220
Alloy AA
6061-T6

Stainless 520-720 45 7780 16.2 0.72 4450

steel BS
970 Grade
304

Carbon 550 16 7820 46.6 234 740

steel
BS970
080M30

Mechanical Engineer S.K Mani,( August 31, 2019), “what is suitable material
transmission shaft key in , and why?”

Plain carbon steel is good enough in 90% of application. The qualities that is required to
good strength and cost effectiveness. The most commonly used is En 8/ASTAM 1040
carbon steel. This is a steel that has a very low sulphur and phosphorous, and contains
0.4% carbon. This helps one to harden it and thereby have high strength. These are
available of the shelf over the counter in a drawn bars or ground bars as a ready to use
material and worldwide availability will be in millions of tons at dirt cheap prices at
almost all diameters. They can be used as shaft without any hassle. Unless circumstances
force you, you never need to go beyond this and this was standardized during world war
and they were used to repair even battle tanks.

Designing is an art of creativity and innovation in affordable option and cost. Some
exceptions occur in case of corrosion or extremely complex designs when you go for
additional processes like alloying, forging, and weight restriction like space application.

A drawn bar is manufactured within a tolerance of h-11 and the key do not need any
additional machining and can be used as it is as a bearing shaft without any important
modification or machining.[6]

Based on the above information Aluminum Alloy AA 6061-T6 is the best material for
both shaft and key.

xx
Summary of Literature Review

Based on the above literature we reviewed, it is clear that stainless steel (BS 970 Grade
304) is the best material for the flanges because it has highest value of tensile strength,
elongation, and is excellent corrosion resistance [2].Steel ( ASTM A193 grade B8MA) is
used for stud bolt materials which has good Tensile Strength, Yield Strength and Elongation
[2]. Due to the above reasons steel (EN8 Mild Steel) is the best material for hub. It has
high value of Ultimate Tensile Strength, Yield Strength and Modulus of Elasticity [3].
For shaft key Aluminum Alloy (Alloy AA 6061-T6) is chosen. The reason for the
selection of Aluminum Alloy is production by extrusion, has good mechanical properties
and exhibits good weld ability [4].

xxi
 CHAPTER THREE

GEOMETRIC ANALYSIS

Figure 3.1 bushed pin coupling

The given parameters for this design of bushed pin coupling are the following:

Specification of coupling

Types of coupling Power(KW) N(R.P.M) Application

Bushed pin 12 700 Compressor

3.1 Methodology

xxii
 cost
stud bolt
analysis

key cost
bushed pin analysis
coupling cost
flange
analysis
cost
hub
analysis

3.2 Design of hub

Figure 3.2 hub

To design a bushed-pin type flexible coupling for alloy steel shaft transmitting 12 Kw at
700 r.p.m. The bearing pressure in the rubber bush and allowable shear stress in the pins
are to be 0.45 N/mm2 and 25 M pa and the Diameter of shaft is 22 mm [4]. To calculate
different Stresses in it we will follow.

Hub:- is the central part of the wheel that connects the axle to the wheel itself. The hub is
designed as a hollow shaft, for the maximum torque transmitted .Based on the
Literature reviewed, for the hub EN8 Mild Steel is chosen. The reason for the
selection of EN8 Mild steel has good mechanical properties which are:-

xxiii
  Density: 7.85 g/cm3
 Brinell Hardness number: 201 BHN
 Rockwell Hardness number: 93 Ra
 Ultimate Tensile Strength: 620 -740MPa
 Tensile Yield Strength: 415MPa
 Modulus of Elasticity : 190-210 G Pa
 Poisson’s ratio: 0.27-0.30
 Melting Point: approx. 1500°C
 Thermal conductivity: 50.7 W/m K

Due to the above reasons EN8 Mild Steel is the best material for hub. It has high value of
Ultimate Tensile Strength, Tensile Yield Strength and Modulus of Elasticity [3].

From the given analysis P = 12k W; N = 700 r.p.m.; first find the torque
transmitted by the shaft, which the material of the shaft is Aluminum Alloy .it has
tensile strength 310Mpa [4].

T = (p×60)/ (2πN) = (12×1000×60)/ (2π×700) = 163.78 Nm≈163Nm.

Then we can find the diameter of the shaft by considering the shaft in shearing.

δ 310
Where the shear stress of the shaft is calculated by 𝜏= == =77.5 N /mm2
2n 2∗2
where 𝜹 and n are yield strength and factor of safety respectively

16 T 16∗163∗1000 Nmm
T = π/ 16 × τ ×d 3 = d= ∛ ( ) = ∛( )=22mm
π∗τ π∗77.5 N /mm2

Then find the dimension of the hub by the following formula.

Outer diameter of the hub (D) = 2d s = 2*22 mm=44mm.

Length of hub (L) = 1.5d s = 1.5*22mm=33mm.

Shear stress induced in hub by considering it as hollow shaft.

π∗τ h 3
16∗T 16∗163∗1000 Nmm
T= ∗¿- d s ) , τ h= = =11.137 N /mm2 =
(D¿¿ 3−d s )∗π =¿ ¿ (44¿¿ 3−223s )∗π ¿
3
16
11.137 M pa

xxiv
3.3 Design for key

Figure 3.3 key

Key is machine element used to prevent relative rotational movement between a shaft and
the parts mounted on it, such as pulleys, gears, wheels, couplings, etc. The reason for the
selection of Aluminum Alloy is production by extrusion, has good mechanical properties
and exhibits good weld ability [4]. .Based on the Literature reviewed, for the key
aluminum alloy is chosen. The reason for the selection of aluminum alloy is
because it has good mechanical properties which are:-
Table 3.1: mechanical properties aluminum alloy

ISO standard AA 6061 – T6

Tensile Yield strength (M pa) 310
Shear Strength (M pa) 190
Proof Stress (M pa) 270
Elongation over 50mm (%) 12
Hardness Vickers (HV) 100
Density(kg/m3) 2700
Thermal Conductivity (W/m k) 166
Melting point (0c) 650

Then we can find parameters of the key by the following formulas

A standard rectangular sun key is used for shaft and hub.

The length of key is obtained by considering the failure of the key in shivery.

τ max=¿ shear on key moment

l=¿ length of key

xxv
 d s =¿ Diameter of shaft

From table 13.1(machine design by Gupta and Kurmi page 472)

Standard dimensions of rectangle sun key for shaft of diameter (22mm)

Width of key W = 8mm

Thickness of key t = 6mm

Length of key (L)=1.5d s =1.5*22=33mm

Considering the key in shearing፡-

d
T = L× w× τ k×
2

T∗2 163∗1000∗2 Nmm

τk = = =56.12 N /mm2
d∗L∗W 22mm∗33 mm∗8 mm

τ k = 56.12 MPa

Considering the key in crushing፡-

t d
T=L× × σc× ,
2 2

4×T 4 ×163∗1000 Nmm

σc = = =149.678 N /mm2
L∗t∗d 33 mm∗6 mmW ∗22 mm

σ c = 149.678 M Pa

3.4 Design for flange

Stainless steel is the best material for flange due to the following reason. It has good
tensile strength, Shear Strength, Proof Stress, and Elongation over 50mm etc.[2]

Then we can find the required dimension for the flange by the following formula.

Thickness of flange (t f ) = 0.5d s =0.5*22mm=11mm, where d s is diameter of the shaft

And also we can find the Shear stress in flange by the following relashinship.

D2 τ t
T=π × c × f,
2

xxvi
 T ∗2 163∗1000 Nmm∗2
τc = , τc = =214.507 N /mm2 =214.507 M Pa
π tf D ,
2 π∗11 mm ¿44 mm
h

3.5 Design for bolt

Figure 3.4 stud bolt

ASTM A193 grade B8MA Is preferable material for bolt due to high tensile strength,
yield strength and elongation etc. after this find the required paramatres by the following
relationship formulas.

0.5 d 0.5∗22 mm
d n= Nominal diameter of bolts = = =4.49 mm ,
√n √6
In order to allow for the bending stress induced due to the compressibility of the rubber
bush, the diameter of the pin (d n) may be taken as 8 mm. d = diameter of the shaft = 22
mm Number of pins (n) = 6

The length of the pin of least diameter d 1 = 8 mm is threaded and secured in the right
hand coupling half by a standard nut and washer. The enlarged portion of the pin which is
in the left hand coupling half is made of 10 mm diameter. On the enlarged portion, a steel
bush of thickness 2 mm is pressed. A steel bush carries a rubber bush. Assume the
thickness of rubber bush as 6 mm. Overall diameter (d r ) of rubber bush,

d r = 10 + 2×t b + 2×t r = 10 + 2×2 + 2×6 = 26 mm.

Diameter of the pitch circle of the pins (d 1)

d P = 2 d + d 2 + 2× n = 2 *22 + 26 + 2× 6 = 82 mm,

Outside diameter of flange ( D2)

D2 = 4d s = 4×22 = 88 mm.

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We can find the Direct stress due to pure torsion in the coupling halves. By the following
π
formula , τ = W (d n ¿ ¿2 , first find load by using this relationship, W = pb × d r ×
4
L=0.45 M Pa*26*L, W=11.7 L since pb(bearing pressure) and L(length of
the bush).

dP 2∗T 2∗163∗1000 Nmm

T = W× n× , W= = = 662.6N
2 n∗d P 6∗82 mm

Then find L from W=11.7 L, L=56.63≈ 57mm

W∗4 4∗662.6 N
τ= = =13.18 N/mm2 , since the induced shear stress in the shaft is less
d 2n∗π ¿¿
than 207 M Pa therefore the design is safe.

xxviii
 CHAPTER FOUR
RESULT AND DISCUSSION
Further test applied on the couplings by accessing torque applied on the free end, the
material limit is showing the optimum results on the failure possibilities when change of
the bush types or removing it, thus to find the main deformation that occurs in the main
coupling body that happens when using different bush like steel, Rubber and Aluminum
or removing it completely. steel bush shows that the both sides of the coupling deforms
with small amount of change due to twisting, while in the Rubber bush the deformation is
less and the torque loss is high as acts like dumper and spring which causes vibrations,
while the Aluminum do not shows any difference compared to the brass as it also causes
much deformation and stress for the coupling, thus the optimum solution is using both
steel and Rubber together to get the best result.
4.1 RESULT
Design for hub

The result we come up with:

Outer diameter of the hub (D) = 2d s = 2*22 mm=44mm.

Length of hub (L) = 1.5d s = 1.5*22mm=33mm.

Shear stress induced in hub by considering it as hollow shaft.

π∗τ h 3
T= ∗¿- d s ) ,
16

16∗T 16∗163∗1000 Nmm

τ h= = =11.137 N /mm2 = 11.137 M pa
(D¿¿ 3−d s )∗π =¿ ¿ (44¿¿ 3−223s )∗π ¿
3

Design for key

Width of key W = 8mm

Thickness of key t = 6mm

Length of key (L)=1.5d s =1.5*22=33mm

Considering the key in shearing፡-

d
T = L× w× τk ×
2

T∗2 163∗1000∗2 Nmm

τK = = =56.12 N /mm2
d∗L∗W 22mm∗33 mm∗8 mm

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τ K = 56.12 M Pa

Considering the key in crushing፡-

t d 4×T 4 ×163∗1000 Nmm

T=L× × σc× ,σ c = = =149.678 N /mm2
2 2 L∗t∗d 33 mm∗6 mmW ∗22 mm

σ c = 149.678 M Pa

Design for flange

Thickness of flange (t f ) = 0.5d s =0.5*22mm=11mm, where d s is diameter of the shaft

And also we can find the Shear stress in flange by the following relashinship.

D2 τ t
T=π × c × f,
2

T ∗2
τc =
π tf D , ,
2
h

163∗1000 Nmm∗2
τc = =214.507 N /mm2 =214.507 M Pa
π∗11 mm ¿44 mm

3.5 Design for bolt

the diameter of the pin (d n)=8mm

d = diameter of the shaft = 22 mm

Number of pins (n) = 6

Overall diameter (d r ) of rubber bush= 26mm

Diameter of the pitch circle of the pins (d 1)

d P = 2 d + d 2 + 2× n = 2 *22 + 26 + 2× 6 = 82 mm,

Outside diameter of flange ( D2)

D2 = 4d s = 4×22 = 88 mm.

We can find the direct stress due to pure torsion in the coupling halves. By the following
π
formula, τ = W (d n ¿ ¿2 , first find load by using this relationship,
4

xxx
 dP 2∗T 2∗163∗1000 Nmm
T = W× n× , W= = = 662.6N
2 n∗d P 6∗82 mm

Then find L from W=11.7 L, L=56.63≈ 57mm

W∗4 4∗662.6 N
τ= = =13.18 N/mm2
d 2n∗π ¿¿

4.2 DISCUSSION

Based on our design calculation we see that calculated shear stress in the shaft
is less than ultimate shear stress 207 M Pa. therefore the design is safe.

Cost analysis
The expenditure for our design is based on the machine cost, labor cost, and
material cost. The cost of material is taken based on the current cost issue in
Ethiopia which is in (ETB). [6]
To calculate the cost for all component of the bushed pin coupling we have to be calculate
the mass of the hub, flange, key and stud bolt for which density of the material
which we use (7850,7780,7700,7750) kg/m3 respectively.
 The volume of the hub can be calculated by this formula:-
π 2 2
V= (d -d ) *L
4 hub shaft
π
V= (44 2-222)*33=0.00003763314 m3
4

The mass of hub can be calculate by;-

m=ρ*V
m=7850) kg/m3*0.00003763314 m3
m=0.2954

Now we can calculate the cost

Cost =m*birr/Kg
For 1 kg of EN8 mild steel 100 birr

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COST=0.2954*100=29.54birr
 The volume of flange can be calculated;-

π 2
V= (d −¿) *t
4 fla

π 2
V= (d −¿)*t
4 fla

π
V= (822−442 )*12
4

V=0.00004512 m3

m=ρ*V
m=7780*0.00004512
m=0.35kg
Cost=m*birr
For 1Kg of stainless steel 110birr

Cost =110birr*0.35Kg

Cost =38.61birr
 The volume of the key can calculate by:-

𝑉=𝐿×𝑤×𝑡

𝑉=𝐿×𝑤×𝑡

V=33*8*6=0.000001584 m3

m=ρ*V
m=7700*0.000001584
m= 0.012Kg
Cost=m*birr

For 1 kg of (AA6061-T6) aluminum alloy 150 birr. [6]

Cost =0.012*150
Cost=1.83birr

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 volume of the stud bolt can be calculated by this formula:-
v=A*L
π 0.9743 2
V= (d n − ) *L
4 n
π 0.9743 2 (
4 (
V= d n−
n )∗2 s +h+n+ rf ) + g where values of s,h,n,rf,g,p are

founded based on the relationship of bolt parameters[8]

π 0.9743 2 (
v=
4(8−
0.055 )∗2 27.3+11+ 0.055+6 ) +2

V=6719.97*6
V=0.00000403 m3

m=ρ*V

m= 7750*0.00000403

m=0.18Kg

Cost=m*birr

For 1Kg of Steel ( ASTM A193 grade B8MA) 130 birr

Cost=0.18*130
Cost= 25birr

Total material cost= cost of hub +cost of flange+ cost of key +cost of stud
bolt.

Mt= 29.5+38.61+1.83+25

Mt=94.94birr

Let’s assume the production take two days

So labor cost=4000ETB+(2*4*60)

So labor cost=4480ETB

Machine cost is the amount of money paid for the machine

Assume the amount of birr paid for the machine is 4500ETB/day

Machine cost = 4500ETB/day*2day

xxxiii
 Machine cost=9000ETB

𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑠𝑡 = 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝑐𝑜𝑠𝑡 + 𝑙𝑎𝑏𝑜𝑟 𝑐𝑜𝑠𝑡 + 𝑚𝑎𝑐ℎ𝑖𝑛𝑒 𝑐𝑜𝑠𝑡

𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑠𝑡 = 94.94 + 4480 + 9000

𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑠𝑡 = 13574.94𝐸𝑇𝐵

CHAPTER FIVE

5. Conclusion and Recommendation

5.1 Conclusion
In this project we have discussed about manual transmission system coupling specially
on bushed pin coupling we have designed, calculated and selected the fundamental parts
of the flange, hub, bolt, and key needed for them. we analyzed and suggested
accordingly at the end of the design its checked and proved safe.

xxxiv
 5. 2 Recommendation
finally, we would like to suggest that extending this project in detail and further analysis
can be made in software like ANSIS to know the most vulnerable parts of the design.

xxxv
 Reference

1. ^https//www.renoldcanada.com/products/couplings/pin and
bush coupling/.
2. ^S.balestra September 2017”project materials”.lugano
swizerland.https//blog.project material.com/flange and
bolt/flange and bolt materials.
3. ^Basavaraj Sajjan.(2016),” Adithya Parthasarathy
Product Design and Development of Wheel Hub for an
All-Terrain Vehicle (ATV)” , Karnataka, India.
4. ^ Essays, UK. (November 2018). Material Selection For
shaft Engineering Essay
5. ^https:-//www.engineeringtoolbox.com/bolt-threads-stress-
d-856.html
6. ^https://m.alibaba.com/showroom/aluminum-price-per-
kg.html
7. ^ R.S khurmi and J.K Gubta (2005). A textbook of machine
design (14th ed) .
8. www.wermac.org/bolt/bolts/method-for-calculating-stud-
bolt-length-for -flanged-connctions.html.

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