speed breaker power generation

Generation of Electricity through Speed Breaker Mechanism

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GENERATION OF ELECTRICITY THROUGH SPEED BREAKERMECHANISM

Department Of Mechanical Engineering

RACHNA COLLEGE OF ENGINEERING AND TECHNOLOGY, GUJRANWALA

(A Constituent College of UET Lahore.)

SESSION 2010

Submitted By

Samiullah Kakar (2010-ME-442)

Project Supervisor

Engr. Muhammad Qasim Tatla

Assistant Professor, Department of Mechanical Engineering

RACHNA COLLEGE OF ENGINEERING AND TECHNOLOGY, GUJRANWALA.


As partial fulfillment of the requirements for the

Bachelor’s Degree

In

MECHANICAL ENGINEERING

This report is submitted to

Department of Mechanical Engineering,

Rachna College of Engineering and Technology, Gujranwala

This is declaring that work submitted in this report is my own, and any work that is not mine has been quoted and acknowledged in the references.

Approved On------------------------------

Internal Examiner: Engr. Muhammad Qasim Tatla

Signature: -----------------------------------------

External Examiner:

Signature: -------------------------------------------

Department of Mechanical Engineering,

Rachna College of Engineering and Technology, Gujranwala

(A Constituent College of UET, Lahore)


Dedication

I dedicate this work to my beloved parents for always supporting me, because they are the driving force in my life and career. Without their love, none of this would matter. Throughout my life, they have actively supported me in my determination to find and realize my potential, and to make this contribution to our world.


Acknowledgements

Thanks to ALLAH ALMIGHTY that enabled me to work in this project because without His approval man can do nothing. After almighty Allah to his prophet, HAZRAT MUHAMMAD (PBUH), the most perfect an exalted forever source of guidance and knowledge humanity as a whole.

There are a number of people without whom this project might not have been written, and to whom I am greatly indebted.

I will forever be thankful to my advisors, Engr. Muhammad Qasim Tatla for supporting me during this study. He has provided insightful discussions about the research. His support and penetrates has allowed me to complete one of my many life goals. I would also thankful to our Honorable teacher Engr. Nouman Javed for guiding me on all my work and project. I value the guidance that was giving to me.

Regards

Samiullah Kakar


ContentsABSTRACT.........................................................................................................................................1

chapter number 1

INTRODUCTION OF THE PROJECT...............................................................................31. INTRODUCTION...................................................................................................................42. SCOPE OF THE PROJECT...............................................................................................4

chapter number 2

DEMONSTRATION OF THE PROJECT..........................................................................51. WORKING PRINCIPLE.......................................................................................................62. BLOCK DIAGRAM................................................................................................................7

chapter number 3

CMODELLING, SIMULATION AND RESULTS........................................................81. FABRICATION DETAILS...................................................................................................92. FABRICATION MODEL SHOWING INNER PARTS............................................93. MATERIALS USED............................................................................................................................................................104. SPECIFICATIONS............................................................................................................................................................105. ADVANTAGES............................................................................................................................................................116. DISADVANTAGE............................................................................................................................................................11

chapter number 4

ACCESSORIES REQUIRED..................................................................................................................................................................12

1. RACK AND PINION............................................................................................................................................................

132. SPROCKET............................................................................................................................................................143. DRIVE ARRANGEMENTS............................................................................................................................................................144. BEST ARRANGEMENTS............................................................................................................................................................155. OTHER ACCEPTABLE ARRANGEMENTS............................................................................................................................................................156. LEAST RECOMMENDED ARRANGEMENTS............................................................................................................................................................167. SPROCKET DIMENSIONAL SPECIFICATIONS............................................................................................................................................................17


chapter number 5

CHAIN DRIVES..................................................................................................................................................................19

1. Chain Drives............................................................................................................................................................202. Chain Drive Design............................................................................................................................................................223. Vibrations............................................................................................................................................................234. Avoiding vibration............................................................................................................................................................245. Chain Types............................................................................................................................................................246. Chain Failures............................................................................................................................................................26

chapter number 6

WHEELS AND SPRINGS..................................................................................................................................................................28

1. Freewheel............................................................................................................................................................292. Flywheel............................................................................................................................................................303. Springs............................................................................................................................................................32

chapter number 7

DESIGN PARAMETER`S AND LIMITATION..................................................................................................................................................................38

1. OUTPUT POWER CALCULATIONS............................................................................................................................................................392. DESIGN SPECIFICATIONS............................................................................................................................................................413. SPROCKET WHEEL AND CHAIN............................................................................................................................................................414. SPRINGS............................................................................................................................................................415. SPUR GEARS............................................................................................................................................................41

COST ANALYSIS..................................................................................................................................................................42

REFERENCES..................................................................................................................................................................46


ABSTRACT

Man in his lifetime, uses energy in one form or the other. In fact whatever happens in nature, results, out of the conversion of energy in one form or the other. The blowing of the wind, the formation of the clouds and the flow of water are a few examples that stand testimony to this fact. The extensive usage of energy has resulted in an energy crisis, and there is a need to develop methods of optimal utilization, which will not only ease the crisis but also preserve the environment. Energy conservation is the cheapest new source of energy. This project attempts to show how energy can be tapped and used at a commonly used system, the generation of electricity through the speed breaker mechanism. Generation of electricity through the speed breaker mechanism is one of the most recent power generation concepts. This device converts the kinetic energy of the vehicles into electric energy by installing movable speed breaker on the road, it takes the stroke motion of the vehicles and converts it to the rotary motion by rack and pinion mechanism and it generates the electricity. This project also explains clearly, the working principle of the designed system, its practical implementation, and its advantages. Design of each component has been carried out using standard procedures, and the components have been fabricated and assembled. A similar model of the system has been modeled using AutoCAD 2007. Practical testing of the system has been done with different loads at different speeds. The utilization of energy is an indication of the growth of a nation. One might conclude that to be materially rich and prosperous, a human being needs to consume more and more energy. And this project is best source of energy that we get in day to day life.


GENERATION OF ELECTRICITY

THROUGH SPEED BREAKER MECHANISM


Chapter Number 1

Introduction of the project

1. INTRODUCTION 2. SCOPE OF THE PROJECT


1. INTRODUCTION:-This project attempts to show how energy can be tapped and

used at a commonly used system- the road speed-breakers. The number of vehicles passing over the speed breaker in roads is increasing day by day. A large amount of energy is wasted at the speed breakers through the dissipation of heat and also through friction, every time a vehicle passes over it. There is great possibility of tapping this energy and generating power by making the speed-breaker as a power generation unit. The generated power can be used for the lamps, near the speed-breakers. In this model we show that how we can generate a voltage from the busy traffic. Conversion of the mechanical energy into electrical energy is widely used concept. It’s a mechanism to generate power by converting the potential energy generated by a vehicle going up on a speed breaker into rotational energy. We have used that simple concept to the project.

2. SCOPE OF THE PROJECT:-The utilization of energy is an indication of the growth of a nation.

For example, World average per capita electricity consumption is 2730 kWh compared to Pakistan’s per capita electricity consumption of 451 kWh. Pakistan has an installed electricity generation capacity of 22,797MW. The average demand is 17,000MW and the shortfall is between 4,000 and 5,000MW. One might conclude that to be materially rich and prosperous, a human being needs to consume more and more energy.

Pakistan is facing serious energy crisis at this time .Pakistan as third world developing country is lot affected by this energy crisis in the world .The major issue is electric crisis which is known as load shedding Pakistan’s small manufacturing markets are lot affected by the rise of energy prices.

By just placing a unit like the “Power Generation Unit from Speed Breakers”, so much of energy can be tapped. This energy can be used for the lights on the either sides of the Roads and thus much power that is consumed by these lights can be utilized to send power to

these villages.

4


Chapter Number 2

Demonstration of the Project

1. WORKING PRINCIPLE 2. BLOCK DIAGRAM


1 WORKING PRINCIPLE:-The project is concerned with generation of electricity from speed

breakers-like set up. The load acted upon the speed breaker - setup is

there by transmitted to rack and pinion arrangements.

Here the reciprocating motion of the speed-breaker is converted

into rotary motion using the rack and pinion arrangement. The axis of

the pinion is coupled with the sprocket arrangement. The sprocket

arrangement is made of two sprockets. One of larger size and the

other of smaller size (free wheel). Both the sprockets are connected by

means of a chain which serves in transmitting power from the larger

sprocket to the smaller sprocket. As the power is transmitted from the

larger sprocket to the smaller sprocket, the speed that is available at

the larger sprocket is relatively multiplied at the rotation of the smaller

sprocket. The axis of the smaller sprocket is coupled to a fly wheel. The

fly wheel is coupled to the shaft at axis of the smaller sprocket. Hence

the speed that has been multiplied at the smaller sprocket wheel is

passed on to this fly wheel of larger dimension. The smaller sprocket is

coupled to the larger fly wheel. So as the larger fly wheel rotates at the

multiplied speed of the smaller sprocket, the smaller sprocket following

the larger sprocket still multiplies the speed to more intensity. Hence,

although the speed due to the rotary motion achieved at the larger

sprocket wheel is less, as the power is transmitted to fly wheel, finally

the speed is multiplied to a higher speed. This speed which is sufficient

to rotate a shaft connected to generator. The rotor (shaft) rotates the

generator. The generator produces the DC current. This DC current is

now sent to the storage battery where it is stored during the day time.

This current is then utilized in the night time for lighting purposes on

the either sides of the road to a considerable distance.

6


2 BLOCK DIAGRAM:-

SPEED BRAKER RACK & PINION Fly wheelAND CHAINARRANGESPROCKET

MENT

ARRANGEMENT

GENERATORBATTERY INVERTER STREET

LIGHTS


Chapter Number 3

Modeling, Simulation andResults

1. FABRICATION DETAILS

2. FABRICATION MODEL SHOWING INNER PARTS

3. MATERIALS USED4. SPECIFICATIONS5. ADVANTAGES6. DISADVANTAGE


1. FABRICATION DETAILS:-The frame structure for the total unit is fabricated using L-Angle

frames and ordinary frames. These frames are made of mild steel.

They are held to proper dimensions are attached to form a unit with

the help of welding. Then the bearings which are of standard make are

kept in place with their respective shafts through them and are welded

to the frame structure. The shafts are also made of mild steel. Hinges

are used to move the speed breaker arrangement by welding it to the

frame structure. These hinges are responsible for the movement of the

speed breaker in an up and down motion. A rack which are made up of

mild steel is welded to the speed breaker arrangement. A pinion which

is also made up of mild steel and which has Thirty six teeth is fitted on

the shaft initially, and welded. This pinion tooth is exactly made to

mate with the teeth of the rack. A bicycle sprocket and chain

arrangement of standard make is fitted with the larger sprocket on the

top shaft and its smaller sprocket on the bottom shaft. The sprocket

wheels are welded to the shafts. A fly wheel that is made of cast iron is

machined suitably to the precise dimensions in a lathe and is placed on

the shaft with its axis coinciding with the axis of the shaft and is

welded. A special stand arrangement is made to seat the 12v DC

generator using frames. A 12v DC generator is placed within the seat

and is held firm using bolts and nuts.

2. FABRICATION MODEL SHOWING INNER PARTS:-

Wires are connected to the terminals of the DC generator and

its other ends are connected to a Lead-Acid battery. Another wire is

taken from these points on the battery and its other ends are

connected to the positive and negative terminal of an inverter. An

output wire from the inverter is sent to the light.

9


3. MATERIALS USED:-

• Rack -Mild steel

• Pinion -Mild Iron

•Sprocket wheels-

Mild steel

• Chain -Mild steel

•Spur gears -

Cast Iron

• Springs -Mild steel

• Shaft -Mild steel

• Speed breaker - Mild steel

4.SPECIFICATIONS:- Generator - 12v DC generator

Battery - lead acid batteryInverter -

250 w AC inverter


5.ADVANTAGES:- Pollution free power generation.

Simple construction, mature technology, and easy maintenance.

No manual work necessary during generation.

Energy available all year round.

No fuel transportation problem.

No consumption of any fossil fuel which is non-renewable source of energy.

Uninterrupted power generation during day and night.

Maximum utilization of energy.

Load to the piston cylinder arrangement is freely got by movement of vehicles.

No fuel storage is required.

.It will work with light weight and heavy vehicle

6.DISADVANTAGE:- We have to check mechanism from time to time

It can get rusted in rainy season.

11


Chapter Number 4

Rack, Pinion and Sprocket

1. RACK AND PINION2. SPROCKET3. DRIVE ARRANGEMENTS4. BEST ARRANGEMENTS5. OTHER ACCEPTABLE ARRANGEMENTS6. LEAST RECOMMENDED ARRANGEMENTS

7. SPROCKET DIMENSIONAL SPECIFICATIONS


1.RACK AND PINION:- A rack and pinion gears system is composed of two gears. The normal round

gear is the pinion gear and the straight or flat gear is the rack.

A rack and pinion is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. The circular pinion engages teeth on a linear "gear" bar which is called the “rack“.

Rotational motion applied to the pinion will cause the rack to move to the side, up to the limit of its travel.

For example, in a rack railway, the rotation of a pinion mounted on a locomotive or a railcar engages a rack between the rails and pulls a train along a steep slope.

The rack and pinion is also used to convert between rotary and linear motion. The rack is the flat, toothed part, and the pinion is the gear. Rack and pinion can convert from rotary to linear of from linear to rotary motion.

It converts the linear motion of the speed breaker into the circular motion needed to turn the shaft.


2. SPROCKET:-A sprocket or sprocket-wheel is a profiled wheel with teeth or cogs

that mesh with a chain, track or other perforated or indented material. The name "sprocket" applies generally to any wheel upon which are radial projections that engage a chain passing

over it. It is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have teeth and pulleys are smooth. The word "sprockets" may also be used to refer to the teeth on the wheel.

Sprockets are used in bicycles, motorcycles, cars, tracked vehicles, chainsaws and other machinery either to transmit rotary motion between two shafts where gears are

unsuitable or to impart linear motion to a track, tape etc. Perhaps the most common form of sprocket may be found in the bicycle, in which the pedal shaft carries a large sprocket-wheel, which drives a chain, which, in turn, drives a small sprocket on the axle of the rear wheel. Early automobiles were also largely driven by sprocket and chain mechanism, a practice largely copied from bicycles.

Sprockets are of various designs, a maximum of efficiency being claimed for each by its originator. Sprockets typically do not have a flange. Some sprockets used with timing belts have flanges to keep the timing belt centered. Sprockets and chains are also used for power transmission from one shaft to another where slippage is not admissible, sprocket chains being used instead of belts or ropes and sprocket-wheels instead of pulleys. They can be run at high speed and some forms of chain are so constructed as to be noiseless even at high speed.

3. DRIVE ARRANGEMENTS:-Relative position of sprockets in drives should receive careful consideration. Satisfactory operation can be secured with the centerline of the drive at any angle to the horizontal, if proper consideration is given. Certain arrangements require less attention and care than others are, therefore, less apt to cause trouble. Various

arrangements are illustrated in the diagrams. The direction of rotation of the drive sprocket is indicated.

14


4. BEST ARRANGEMENTS:-Arrangements considered good practice are illustrated in Figs. 1, 2, 3, and 4. The direction of rotation of the drive sprockets in Figs. 1 and 4 can be reversed.

5. OTHER ACCEPTABLE ARRANGEMENTS:-If none of the above arrangements can be followed, an attempt should be made to use an arrangement as illustrated in Figs. 5, 6, and 7.


When the large sprocket is directly above the small sprocket, Fig. 8, a drive cannot operate with much chain slack. As the chain wears, shaft-center distance must be adjusted or an idler be placed against the outside of the slack strand (near the small sprocket) to adjust slack and keep the chain in proper contact with the small sprocket. With the drive slightly inclined, Fig. 5, less care will be required, because the weight of the slack chain strand helps to maintain better contact between the chain and the sprockets. Where center distances is short, or drives nearly horizontal, the slack should be in the bottom strand, especially where take-up adjustment is limited, Fig. 6 rather than Fig. 9. An accumulation of slack in the top strand may allow the chain to be pinched between the sprockets, Fig. 9. When small sprockets are used on horizontal drives, it is better to have the slack strand on the bottom, Fig. 7, rather than on the top, Fig. 10. Otherwise, with the appreciable amount of slack, the strands may strike each other.

6. LEAST RECOMMENDED ARRANGEMENTS:-


American sprocket manufacturers have adopted 4 specific

types of sprocket Construction styles as American Standards.

In addition to the standard sprockets, Special sprockets may

be available in the same styles.

Style A - Flat sprocket with no hub extension either side.

Style B - Sprocket with hub extension one side.

Style C - Sprocket with hub extension both sides.

Style D - Sprocket with a detachable bolt on hub attached to a plate.

7.SPROCKET DIMENSIONAL SPECIFICATIONS:- a. Bottom Diameter (B.D.):

The diameter of a circle tangent to the bottoms of the tooth spaces.

b. Caliper Diameter:

Since the bottom diameter of a sprocket with odd number of teeth cannot be measured directly, caliper diameters are the

measurement across the tooth spaces nearly opposite.

17


c. Pitch Diameter (P.D.):

The diameter across to the pitch circle which is the circle Followed by the centers of the chain pins as the sprocket revolves in mesh with the chain.PD = PITCH

SIN (180/Nt)

d. Outside Diameter (O.D.):

The measurement from the tip of the sprocket tooth across to the corresponding point directly across the sprocket. It is comparatively unimportant as the tooth length is not vital to proper meshing with the chain. The outside diameter may vary depending on type of cutter used.

OD = (Pitch) (.6 + COT [180 / Nt])

e. Hub Diameter (HOD):

That distance across the hub from one side to another. This diameter must not exceed the calculated diameter of the inside of the chain side bars.

f. Maximum Sprocket:

Maximum Sprocket Bore is determined by the required Bore hub wall thickness for proper strength. Allowance must be made for keyway and setscrews.

g. Face Width:

Face width is limited in its maximum dimension to allow proper clearance to provide for chain engagement and disengagement. The minimum width is limited to provide the proper strength to carry the imposed loads.

h. Length thru Bore:

Length Thru Bore (or L.T.B.) must be sufficient to allow (LTB) a long enough key to withstand the torque transmitted by the shaft. This also assures stability of the sprocket on the shaft.


Chapter Number 5

Chain Drives

1. Chain Drives2. Chain Drive Design3. Vibrations4. Avoiding vibration5. Chain Types6. Chain Failures

19


1.CHAIN DRIVES: Chain drives are a

means of transmitting power like gears, shafts and belt drives

Characteristics High axial stiffness

Low bending stiffness

High efficiency

Relatively cheap

History and development

First belt drives: China c100 BC

First chain drives: Roman c200 AD


Leonardo DaVinci: sketch of leaf type chain c1500 AD – many similarities to modern chains.

Galle chains: 19th century first mass produced roller chains (no bushes).

Hans Renold (Switzerland) 1880 – invented modern bush roller chain

Bush Roller Chains:

Parts of a bush roller chain,


Terminology:

Manufacture:

Bushes and pins: cold drawn, cropped, turned/ground, case hardened, ground again and shot peened.

Side-plates are stamped from plate.

Assembly

Pins and bushes are press-fitted into appropriate side plates.

2. CHAIN DRIVE DESIGN:-Chain length and center distance:

Chain must contain even integer number of links

•Hence cannot pick an arbitrary center distance and chain pitch

•Nearest chain lengths (in pitches) for a contemplated center distance, CC

, are calculated by empirical formulae like (for a two sprocket system:

Where N1and N2 is the numbers of teeth on sprockets and P is the chain pitch.

The result of which should be ROUNDED UP to the next even

number to calculate the actual center separation, CA:


Inertial force in chain:

In addition to the tension required to transmit power, chain tension also provides centripetal force to move links around sprockets

The extra inertial force, Fcf, is given by:

3.Vibrations: Chain between sprockets can vibrate like a string

Basicequation for natural frequency, fn, of taught string

Where F is the tension, m is the mass per unit length, L is the length and k is the mode number


For tight side of chain there are typically ranges of resonant frequencies given by:

Where,

Fc is the tight span tension (excluding inertial contribution)

4.Avoiding vibration:- To avoid the chain resonating, need to avoid having sources of

excitation with frequencies near possible resonant frequencies

Obvious source is impact of sprocket teeth on chain

Frequency of these occurs at:

Where ω is the sprocket rotation speed and N is the number of teeth.

5.Chain Types:- 1) Transmission chains Chains to transmit rotary power between shafts

Bush roller chains are transmission chains

For more power capacity, multi-strand transmission chains are used


2) Conveyor chain

Rollers sit proud of links and can roll along supporting surface.

Can be used for transporting materials, as roller scan support weight.

Can also be used just to support weight of chain if transmitting power over long distances.

3) Inverted tooth (or silent) chain Sprocket teeth mesh with shaped links instead of rollers on chain

Joints between links use rolling rather than sliding contact

Profile of links are more like involute gear teeth Overall effect is to reduce noise


4) Leaf (or lifting) chain

Designed for lifting rather (than power transmission)

Do not have to mesh with sprockets, hence no rollers

Therefore can narrower than roller chain with equivalent strength

Example: fork-lift truck

6.Chain Failures:- Failures caused by poor selection

Overload

Failure of side plates due to cyclic load fatigue

Failure of bush or roller due to impact fatigue

Above failures can still occur due to poor installation or maintenance

Misalignment

Incorrect or failed lubrication system

If correct chain is selected, installed and maintained the overall life is determined by wear

Causes and effects of chain wear

Caused by material removal as chain components slide relative to each other

Effect of wear is to cause the chain to gradually elongate


As pitch increases, chain sits at larger and large radius on sprockets

Limit is when chain jumps over sprocket teeth Empirical extension limits are

• 2 % for sprockets with less than 200 teeth • 200/N % for sprockets with more than 200 teeth

Wear life

Typically 15,000 hours for any power, chain or sprocket size if correctly selected, installed and maintained.


Chapter Number 6

Wheels and springs

1. Freewheel2. Flywheel3. Springs

28


1. FREEWHEEL:-A freewheels consists of either a single sprocket or a set of sprockets mounted on a body which contains an internal ratcheting mechanism and mounts on a threaded hub.

Mechanics:

The simplest freewheel device consists of two saw-toothed, spring-loaded discs pressing against each other with the toothed sides together, somewhat like a ratchet. Rotating in one direction, the saw teeth of the drive disc lock with the teeth of the driven disc, making it rotate at the same speed. If the drive disc slows down or stops rotating, the teeth of the driven disc slip over the drive disc teeth and continue rotating, producing a characteristic clicking sound proportionate to the speed difference of the driven gear relative to that of the (slower) driving gear.

A more sophisticated and rugged design has spring-loaded steel rollers inside a driven cylinder. Rotating in one direction, the rollers lock with the cylinder making it rotate in unison. Rotating slower, or in the other direction, the steel rollers just slip inside the cylinder.

Advantages:

Free wheel mechanism acts as an automatic clutch, making it possible to change gears in a manual gearbox, either up- or downshifting, without depressing the clutch pedal, limiting the use of the manual clutch to starting from standstill or stopping.

Disadvantages:

The major disadvantage of the multiple sprocket freewheel design is that the drive-side bearing is located inboard of the free wheel, and as sprockets were added over time, moved the bearing farther from the drive-side axle support. This resulted in more flexing stress is placed on the axle which can bend or even break.


2. FLYWHEEL:-A flywheel is a

rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of

its rotational speed. Energy is transferred to a flywheel by applying torque to it, thereby increasing its rotational speed, and hence its stored energy. Conversely, a flywheel releasesstored energy by applying torque to a mechanical load, thereby decreasing its rotational speed.

Energy Stored in a Flywheel:

A flywheel is shown in Fig. when a flywheel absorbs energy its speed increases and when it gives up energy its speed decreases.

Let m= Mass of the flywheel in kg,

k = Radius of gyration of the flywheel in meters,

I = Mass moment of inertia of the flywheel about the axis of rotation in kgm2=m.k2,

N1and N2 = Maximum and minimum speeds during the cycle in r.p.m,

ω1and ω2 = Maximum and minimum angular speeds during the

cycle in rad / s,

N= Mean speed during the cycle in r.p.m.

30


The radius of gyration (k) may be taken equal to the mean radius of the rim (R), because the thickness of rim is very small as compared to the diameter of rim. Therefore substituting k= R in equation (ii), we have

E=m.R2.ω2.CS= m.v2.CS ( v= ω.R)

From this expression, the mass of the flywheel rim may be determined.

Notes: 1.In the above expression, only the mass moment of inertia of the rim is considered and the mass moment of inertia of the hub and arms is neglected. This is due to the fact that the major portion of weight of the flywheel is in the rim and a small portion is in the hub and arms. Also the hub and arms are nearer to the axis of rotation, therefore the moment of inertia of the hub and arms is very small.

2.The density of cast iron may be taken as 7260 kg / m3 and for cast steel, it may taken as 7800 kg / m3.

3.The mass of the flywheel rim is given by

m= Volume × Density = 2 πR× A× ρ

31


From this expression, we may find the value of the cross-sectional area of the rim. Assuming the cross-section of the rim to be rectangular, then

A=b× t

where b= Width of the rim, and

t = Thickness of the rim.

Knowing the ratio of b/twhich is usually taken as 2, we may find the width and thickness of rim.

4. When the flywheel is to be used as a pulley, then the width of rim should be taken 20 to 40 mm greater than the width of belt.

3. SPRINGS:-A spring is defined as an elastic body, whose function is to distort

when loaded and to recover its original shape when the load is removed. The various important applications of springs are as follows :

1.To cushion, absorb or control energy due to either shock or vibration as in car springs, railway buffers, air-craft landing gears, shock absorbers and vibration dampers.

2.To apply forces, as in brakes, clutches and springloaded valves.

3.To control motion by maintaining contact between two elements as in cams and followers.

4.To measure forces, as in spring balances and engine indicators.

5.To store energy, as in watches, toys, etc.


Types of Springs:

Though there are many types of the springs, yet the following, according to their shape, are important from the subject point of view.

Helical springs:

The helical springs are made up of a wire coiled in the form of a helix and is primarily intended for compressive or tensile loads. The cross-section of the wire from which the spring is made may be circular, square or rectangular. The two forms of helical springs are compression helical springas shown in Fig. (a) and tension helical spring as shown in Fig. (b).

Advantages:

(a) These are easy to manufacture.

(b) These are available in wide range.

(c) These are reliable.

(d) These have constant spring rate.

(e) Their performance can be predicted more accurately.

(f)Their characteristics can be varied by changing dimensions.


Conical and volute springs:

The conical and volute springs, as shown in Fig. are used in special applications where a telescoping spring or a spring with a spring rate that increases with the load is desired. The conical spring, as shown in Fig.(a), is wound with a uniform pitch whereas the volute springs, as shown in Fig. (b), are wound in the form of parabolic with constant pitch and lead angles. The springs may be made either partially or completely telescoping. This characteristic is sometimes utilized in vibration problems where springs are used to support a body that has a varying mass.


Torsion springs:

These springs may be of helical or spiral type as shown in Fig. The helical type may be used only in applications where the load tends to wind up the spring and are used in various electrical mechanisms. The spiral type is also used where the load tends to increase the number of coils and when made of flat strip are used in watches and clocks.

The major stresses produced in torsion springs are tensile and compressive due to bending.

Laminated or leaf springs:

The laminated or leaf spring (also known as flat spring or carriage spring) consists of a number of flat plates (known as leaves) of varying lengths held together by means of clamps and bolts, as shown in Fig. These are mostly used in automobiles.

The major stresses produced in leaf springs are tensile and compressive stresses.

Laminated or leaf springs. Disc or Bellevile springs.

35


Values of allowable shear stress, Modulus of elasticity and Modulus of rigidity for various spring materials.

36


Standard Size of Spring Wire:

Standard wire gauge (SWG) number and corresponding diameter of spring wire.


Chapter Number 7

Design Parameter`s andLimitations

1 . OUTPUT POWER CALCULATIONS

2 . DESIGN SPECIFICATIONS

3 . SPROCKET WHEEL AND CHAIN

4 . SPRINGSSPUR GEARS

38


1. OUTPUT POWER CALCULATIONS:-Let us consider,

The mass of a vehicle moving over the speed breaker =

10Kg (Approximately)

Height of speed brake = 10 cm

Work done = Force x Distance

Here,

Force = Weight of the Body

= 10 Kg x 9.81

= 98.1 N

Distance traveled by the body = Height of the

speed brake = 10 cm

Output power = Work done/Sec

=(89.1 x 0.10)/60

=0.1485 Watts (For One pushing force)

Power developed for 1 vehicle passing over the speed breaker

arrangement for one minute

Power developed for 60 minutes (1 hr)

Power developed for 24 hours

= 0.1485 watts

= 8.91 watts

= 213.84watts


Velocity Ratio of Chain Drives:

The velocity ratio of a chain drive is given by

. . = 1 = 2

2 1

N1= Speed of rotation of smaller sprocket in r.p.m.,

N2= Speed of rotation of larger sprocket in r.p.m.,

T1= Number of teeth on the smaller sprocket, and

T2= Number of teeth on the larger sprocket.

. . = 1 = 2

2 1

. . = 3619 = 1.894Experimentally,

Revolution

Revolution of shaft by one push:

Using tachometer, 100 rpm =1.666rps

Torque:

Torque produce in on push:

= × 602

0.148 × 60= = 0.8512 1.666

40


2. DESIGN SPECIFICATIONS:-• SHAFT (DIA) = 65 mm

•Diameter of flywheel

= 540 mm

•Thickness of flywheel

= 20 mm

3.SPROCKET WHEEL AND CHAIN:- • No of teeth on large sprocket =36

• No of teeth on small sprocket =19

• Dia of large sprocket=460 mm

• Dia of small sprocket= 230 mm

• Length of chain=1620 mm

•Optimum centre distance

= 560 mm

4. SPRINGS:-

• Diameter of wire= 2 mm

• Mean dia of coil= 12 mm

•Free length of spring

= 300mm

5. SPUR GEARS:-• No Of Teeth On Rack = 36

• Rack Length = 230mm

• No Of Teeth On Pinion =36

•Diameter Of Pinion Gear =270mm

• Thickness of pinion =20mm

gear

•Length of speed breaker =290mm

•Width of speed breaker =220mm

•Height of speed breaker =130mm

41


COST ANALYSIS:-Cost:

It is defined as the amount of expenditure occurred in bringing out a product.

Cost is expressed along with the atom viscose of bicycle axle Rs.15/- per axle cost of bearing Rs.150/.Bearing.

Cost of Elements:

The different cost is placed in three categories.

Material Cost

Labor Cost

Other Expenses

Material Cost:

It is the cost on the material, which is converted into product. This is of two types:

Direct Material Cost

It is cost of all those materials which when worked upon become the integral part of the product. For example lathe bed casting when machined, heat treated and grounded becomes a lathe bed.

Indirect Material Cost

All those materials, which are consumed during manufacturing for processing a product, but do not become part of product. For example electric energy, cutting oil, grease, water and cotton waste.

Prime Cost

This is also known as direct cost. Prime Cost = direct material cost + direct labor cost and expenses

Factory Cost

This is also known as factory cost. Factory cost = prime cost + factory expenses.


Office Cost

This is also known as production office cost = factory cost + administrative expenses + all and the expenses.

Total Office

This is also known as selling cost. Total cost = office cost + selling and distribution expenses

Selling price of product

Selling cost = total cost + profit loss

Brake Even Chart:

This is graphical illustration to show loss and profit region. This type is deciding the no of units to be made at which three is neither any loss nor any profit. It is arrived it a following

Fixed Cost:

This is the cost, independent of product. This cost is three even if the product is nil.

Labor cost

It is the labor which converts raw material into product which tools and machines and hence the cost over the labor

Direct Labor cost

All the labors are working on the machines and material who can be identified with the product, are called direct labor and hence cost over them. For example, a lathe operator, a milling man.

Indirect labor cost

All the labors that help in manufacturing cycle but cannot be identified directly with a particular product and hence cost over them. For example, Sweepers, gate keepers, rigors, store keepers etc.

Other Expenses

All those expenses not covered under labor and material cost fall under this category. They are also of two types.


Direct expenses

All those expense, which can be assigned to a particular job, are placed in this category. This will include the following.

Expenses incurred in preparing design, drawing and process sheet.

Cost of jobs, fixtures is any made / hired for the job.

Patterns used for the mold.

Any consultation fee paid for the job.

Indirect expenses

All other expenses left out for above. They make a major part of the cost. These expenses are of following type.

Factory Expenses

This is also known as “factory over heads”, factory on cost on work on cost.

Administrative expenses

This is also known as office on cost.

Selling expenses

Distribution expenses

R & D expenses

Selling price of product, It can be calculated as follows:


Selling price of pipe bending machine:

Prime Cost:

Prime cost = material cost + labor cost

+ other cost. =Rs,4500/.

Bearing, cutting tool, screw etc. = Rs500/.

Material cost = Rs3500.

Labor cost = 15hrs (no of machine operators * Rs50 per hour)

=15 hour (5* Rs50 per hour)

=500 Rs.

Other expenses:

= manufacturing process (painting + machines and

energy consumed) Other expenses = 500 + 15hours

10Rs/hour

= 650/.

Factory Cost:

Factory cost = prime cost + factory

expenses = 4500 + 500 = Rs5000.

Total cost:

Total cost = office cost + selling cost and distribution cost =Rs 10150.

Selling cost:

Selling cost = total cost + profit lose.

=10150 + (10 % * total cost)

=10150 + (10 * 10150/100) = Rs. 11155

By adding the general sales taxes = selling cost + 16% =

11155 + 16% = Rs. 12939

Selling Cost = Rs. 1293945


REFERENCES:-

I. Department of Mechanical Engineering Queen’s Building, University of Bristol, Bristol, BS8 1TR, UKII. A Textbook of Machine Design by R.S.KHURMI AND

J.K.GUPTA. III. Automobile Engineering , KirpalSingh. IV. Automobile Engineering, S.M.Pandey& K.K. Shah.V. www.wikipedia.com. VI. Shigley Tata McGraw hills (Machine Design).

VII. Generation of Electricity through Speed Breaker Mechanism. (Alok Kumar Singh, Deepak Singh, Madhawendra Kumar , Vijay Pandit, Prof.SurendraAgrawal).

VIII. EVERY SPEED BREAKER IS NOW A SOURCE OF POWER. (ASWATHAMAN.V ELECTRONICS AND COMMUNICATION ENGINEERING SONA COLLEGE OF TECHNOLOGY SALEM, INDIA). (PRIYADHARSHINI.M ELECTRONICS AND COMMUNICATION ENGINEERING SONA COLLEGE OF TECHNOLOGY SALEM, INDIA).

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