2. Generation of Electricity through Speed Breaker Mechanism
GENERATION OF ELECTRICITY THROUGH SPEED BREAKER MECHANISM 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.
3. Generation of Electricity through Speed Breaker Mechanism
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)
4. Generation of Electricity through Speed Breaker Mechanism
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 our world.
5. Generation of Electricity through Speed Breaker Mechanism
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
6. Generation of Electricity through Speed Breaker Mechanism
Contents
ABSTRACT ........................................ 1
chapter number 1
INTRODUCTION OF THE PROJECT .............................................................. 3
1. INTRODUCTION ..................................................... 4
2. SCOPE OF THE PROJECT ...................................... 4
chapter number 2
DEMONSTRATION OF THE PROJECT.......................................................... 5
1. WORKING PRINCIPLE .......................................... 6
2. BLOCK DIAGRAM ................................................ 7
chapter number 3
CMODELLING, SIMULATION AND RESULTS ............................................... 8
1. FABRICATION DETAILS .......................................... 9
2. FABRICATION MODEL SHOWING INNER PARTS ............................................................. 9
3. MATERIALS USED ................................................. 10
4. SPECIFICATIONS ................................................. 10
5. ADVANTAGES ....................................................... 11
6. DISADVANTAGE ................................................... 11
chapter number 4
ACCESSORIES REQUIRED ............................................ 12
1. RACK AND PINION............................................. 13
2. SPROCKET ............................................................ 14
3. DRIVE ARRANGEMENTS ..................................... 14
4. BEST ARRANGEMENTS ........................................ 15
5. OTHER ACCEPTABLE ARRANGEMENTS ............................................ 15
6. LEAST RECOMMENDED ARRANGEMENTS ...................................... 16
7. SPROCKET DIMENSIONAL SPECIFICATIONS ................................. 17
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ABSTRACT
Man in his lifetime, uses energy one form or the other. In fact whatever happens nature, results, out of the conversion energy in one form or the other. The blowing of the wind, the formation of clouds and flow water are a few examples that stand testimony to this fact. The extensive usage of energy has resulted in an 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 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 vehicles into electric energy by installing movable speed breaker on the road, it takes 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 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 the growth a nation. One might conclude that to be materially rich and prosperous, a human being needs to consume more and energy. And this project is best source of energy that we get in day to life.
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GENERATION OF ELECTRICITY THROUGH SPEED BREAKER MECHANISM
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Introduction of the project
1. INTRODUCTION
2. SCOPE OF THE PROJECT
Chapter Number 1
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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 wasted at the speed breakers through the dissipation of heat and also 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 can be used for the lamps, near speed-breakers. In this model we show that how can generate a voltage from the busy traffic. Conversion of 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.
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Chapter Number 2
Demonstration of the Project
1. WORKING PRINCIPLE
2. BLOCK DIAGRAM
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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 speed-breaker is converted into rotary motion using the rack and pinion arrangement. The axis of is coupled with sprocket arrangement. The sprocket arrangement is made of two sprockets. One 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 smaller sprocket. As the power is transmitted from larger sprocket to smaller sprocket, speed that is available at the larger sprocket relatively multiplied at the rotation of 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 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 wheel rotates at the multiplied speed of smaller sprocket, sprocket following the larger sprocket still multiplies the speed to more intensity. Hence, although due rotary motion achieved at the larger sprocket wheel is less, as power is transmitted to fly wheel, finally the speed is multiplied to a higher speed. This which sufficient to rotate a shaft connected to generator. The rotor (shaft) rotates the generator. generator produces the DC current. This current is now sent to the storage battery where it is stored during the day time. This current then utilized in night time for lighting purposes on the either sides of road to a considerable distance.
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2 BLOCK DIAGRAM:-
SPEED BRAKER ARRANGE MENT BATTERY INVERTER STREET LIGHTS GENERATOR RACK & PINION AND CHAIN SPROCKET ARRANGEMENT Fly wheel
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Chapter Number 3
Modeling, Simulation and Results
1. FABRICATION DETAILS
2. FABRICATION MODEL SHOWING INNER PARTS
3. MATERIALS USED
4. SPECIFICATIONS
5. ADVANTAGES
6. DISADVANTAGE
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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 held to proper dimensions are attached to form a unit with the help of welding. Then bearings which 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 used move speed breaker arrangement by welding it to the frame structure. These hinges are responsible for the movement of 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 has Thirty six teeth fitted on the shaft initially, and welded. This pinion tooth is exactly made to mate with the teeth of rack. A bicycle sprocket and chain arrangement of standard make is fitted with the larger sprocket on the top shaft and its smaller bottom shaft. The wheels are welded to the shafts. A fly wheel that is made of cast iron machined suitably to the precise dimensions in a lathe and is placed on the shaft with its axis coinciding axis of the shaft and is welded. A special stand arrangement made to seat 12v DC generator using frames. A 12v DC generator is placed within the seat and held firm using bolts and nuts.
2. FABRICATION MODEL SHOWING INNER PARTS:-
Wires are connected to the terminals of DC generator and its other ends 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 negative terminal of an inverter. An output wire from the inverter is sent to light.
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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 battery
Inverter - 250 w AC inverter
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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 It can get rusted in rainy season.
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Chapter Number 4
Rack, Pinion and Sprocket
1. RACK AND PINION
2. SPROCKET
3. DRIVE ARRANGEMENTS
4. BEST ARRANGEMENTS
5. OTHER ACCEPTABLE ARRANGEMENTS
6. LEAST RECOMMENDED ARRANGEMENTS
7. SPROCKET DIMENSIONAL SPECIFICATIONS
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1. RACK AND PINION:-
A rack and pinion gears system is composed of two gears. The normal round gear the pinion gear and straight or flat is rack.
A rack and pinion is a type of linear actuator that comprises pair 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 rack move side, up the limit of its travel.
For example, in a rack railway, the rotation of pinion mounted on locomotive or a railcar engages rack between the rails and pulls a train along steep slope.
The rack and pinion is also used to convert between rotary linear motion. rack is the flat, toothed part, and the pinion is gear. Rack and can convert from rotary to linear of linear to rotary motion.
It converts the linear motion of the speed breaker into the circular motion needed to turn the shaft.
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2. SPROCKET:-
A sprocket or sprocket-wheel is a profiled wheel with teeth or cogs that mesh with a chain, track or other perforated 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 the teeth on 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 drive at any angle to 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.
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4. BEST ARRANGEMENTS:-
Arrangements considered good practice are illustrated in Figs. 1, 2, 3, and 4. The direction of rotation 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 made to use arrangement as illustrated in Figs. 5, 6, and 7.
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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 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 sprockets. Where center distances is short, or drives nearly horizontal, the slack should be in 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:-
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American sprocket
manufacturers have adopted 4 specific types of 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 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 teeth cannot be measured directly, caliper diameters are the measurement across the tooth spaces nearly opposite.
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c. Pitch Diameter (P.D.):
The diameter across to the pitch circle which is Followed by the centers of the chain pins as sprocket revolves in mesh with the chain. PD= PITCHSIN (180/Nt)
d. Outside Diameter (O.D.):
The measurement from the tip of 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 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 withstand the torque transmitted by the shaft. This also assures stability of the sprocket on the shaft.
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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
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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,
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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, C
, 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 calculate actual center separation, CA:
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Inertial force in chain:
In addition to the tension required transmit power, chain 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
Basic equation for natural frequency, fn, of taught string
Where F is the tension, m mass per unit length, L the length and k is the mode number
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For tight side of chain there are typically ranges resonant frequencies given by:
Where,
Fc is the tight span tension (excluding inertial contribution)
4. Avoiding vibration:-
To avoid the chain resonating, need to having sources of excitation with frequencies
near possible resonant Obvious source is impact of sprocket teeth on chain
Frequency of these occurs at:
Where ω is the sprocket rotation speed and N 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
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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
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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 gradually elongate
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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.
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Chapter Number 6
Wheels and springs
1. Freewheel
2. Flywheel
3. Springs
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1. FREEWHEEL:- A freewheels consists of either a single sprocket or set sprockets mounted on 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.
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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 releases stored 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 the flywheel in meters,
I = Mass moment of inertia the flywheel about 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.
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The radius of gyration (k) may be taken equal to the mean 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
Δ E=m.R2.ω2.CS= m.v2.CS ( v= ω.R)
From this expression, the mass of flywheel rim may be determined.
Notes: 1.In the above expression, only mass moment of inertia the rim is considered and the mass moment of inertia the hub and arms is neglected. This due to fact that the major portion of weight flywheel is in the rim and a small portion hub and arms. Also the arms are nearer to the axis of rotation, therefore the moment of inertia 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
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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.
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Types of Springs:
Though there are many types of the springs, yet 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 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.
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Conical and volute springs:
The conical and volute springs, as shown in Fig. are used in special applications where a telescoping spring or a with rate that increases 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 varying mass.
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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 spring and are in various electrical mechanisms. The spiral type is also used where the load tends to increase the number of coils and when made flat strip are used in watches 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 carriage spring) consists of a number flat plates (known as leaves) 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.
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Values of allowable shear stress, Modulus elasticity and of rigidity for various spring materials.
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Standard Size of Spring Wire:
Standard wire gauge (SWG) number and corresponding diameter of spring wire.
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Chapter Number 7
Design Parameter`s and Limitations
1. OUTPUT POWER CALCULATIONS
2. DESIGN SPECIFICATIONS
3. SPROCKET WHEEL AND CHAIN
4. SPRINGSSPUR GEARS
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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
= 0.1485 watts
Power developed for 60 minutes (1 hr) = 8.91 watts
Power developed for 24 hours = 213.84watts
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Velocity Ratio of Chain Drives:
The velocity ratio of a chain drive is given by 푉.푅.= 푁1 푁2= 푇2 푇1
N1= Speed of rotation smaller sprocket in r.p.m.,
N2= Speed of rotation larger sprocket in r.p.m.,
T1= Number of teeth on the smaller sprocket, and
T2= Number of teeth on the larger sprocket.
푉.푅.= 푁1 푁2=푇2 푇1
푉.푅.= 3619 =1.894
Experimentally,
Revolution
Revolution of shaft by one push:
Using tachometer, 100 rpm =1.666rps
Torque:
Torque produce in on push: 푇= 푃×602휋푁
푇= 0.148×602휋1.666 = 0.851 푁푚
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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 gear =20mm
• Length of speed breaker =290mm
• Width of speed breaker =220mm
• Height of speed breaker =130mm
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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 material, which 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 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 + labor and expenses
Factory Cost
This is also known as factory cost. Factory cost = prime + expenses.
50. Generation of Electricity through Speed Breaker Mechanism
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Office Cost
This is also known as production office cost = factory + administrative expenses + all and the expenses.
Total Office
This is also known as selling cost. Total cost = office + and distribution expenses
Selling price of product
Selling cost = total + 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 profit. It arrived it a following
Fixed Cost:
This is the cost, independent of product. cost three even if product is nil.
Labor cost
It is the labor which converts raw material into product tools and machines hence the cost over labor
Direct Labor cost
All the labors are working on machines and material who can be identified with 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 this category. They are also of two types.
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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 are of following type.
Factory Expenses
This is also known as “factory over heads”, on cost work 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:
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Selling price of pipe bending machine:
Prime Cost:
Prime cost = material + labor 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 + factory expenses
= 4500 + 500 Rs5000.
Total cost:
Total cost = office + selling cost and distribution =Rs 10150.
Selling cost:
Selling cost = total + 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. 12939
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REFERENCES:-
I. Department of Mechanical Engineering Queen’s Building, University of Bristol, BS8 1TR, UK
II. A Textbook of Machine Design by R.S.KHURMI AND J.K.GUPTA.
III. Automobile Engineering , KirpalSingh.
IV. Automobile Engineering, S.M.Pandey& 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).
