DESIGN AND FABRICATION OF SHAFT DRIVEN BICYCLE-MINI PROJECT

A PROJECT REPORT

ABSTRACT

                    This project is developed for the users to rotate the back wheel of a two wheeler  using solid shaft. Usually in two wheelers, chain and sprocket method is used  to drive the back wheel. But in this project, the bevel gears are connected to the end of the shaft. The shaft of the engine is connected with a long rod. The other side of the long rod is connected with a set of bevel gears. The bevel gears are used to rotate the shaft in 90 degree angle. The back wheel of the vehicle is connected with the bevel gear (driven). Thus the back wheel is rotated in perpendicular to the engine shaft. Thus the two wheeler will move forward. According to the direction of motion of the engine, the wheel will be moved forward or reverse. In this  method rotary motion is converts to linear motion with aid of two bevel gears.

Keywords: Bevel gears, Drive shaft, chain and sprockets, Power transmission and Cast iron.

CHAPTER 1

INTRODUCTION

1.1 THEORY               

                A shaft-driven bicycle is a bicycle that uses a drive shaft instead of a chain to  transmit power from the pedals to the wheel arrangement displayed in the   following fig 1. Shaft drives were introduced over a century ago, but were mostly supplanted by chain-driven bicycles due to the gear ranges possible with sprockets and derailleur. Recently, due to advancements in internal gear technology, a small number of modern shaft-driven bicycles have been introduced. Shaft-driven bikes have a large bevel gear where a conventional bike would have its chain ring. This  meshes with another bevel gear mounted on the drive shaft which is shown in fig1.

Fig.1.1. Replacement of chain drive bicycle with driveshaft

              

                  The use of bevel gears allows the axis of the drive torque from the pedals to be turned through 90 degrees. The drive shaft then has another bevel gear near the rear wheel hub which meshes with a bevel gear on the hub here the rear sprocket would be on a conventional bike, and canceling out the first drive torque change of

axis.

1.2 History

                  The first shaft drives for cycles appear to have been invented independently in 1890 in the United States and England. A. Fearnhead, of 354 Caledonian Road, North London developed one in 1890 and received a patent in October 1891. His prototype shaft was enclosed within a tube running along the top of the chain stay; later models were enclosed within the actual chain stay. In the United States, Walter Still man filed for a patent on a shaft-driven bicycle on Dec. 10, 1890 which was granted on July 21, 1891.

                The shaft drive was not well accepted in England, so in 1894 Fearnhead took it to the USA where Colonel Pope of the Columbia firm bought the exclusive American rights. Belatedly, the English makers took it up, with Humber in particular plunging heavily on the deal. Curiously enough, the greatest of all the Victorian cycle engineers, Professor Archibald Sharp, was against shaft drive; in his classic 1896 book "Bicycles and Tricycles", he writes "The Fearnhead Gear.... if bevel-wheels could be accurately and cheaply cut by machinery, it is possible that gears of this description might supplant, to a great extent, the chain-drive gear; but the fact that the teeth of the bevel-wheels cannot be accurately milled is a serious obstacle to their practical success".

                 In the USA, they had been made by the League Cycle Company as early as 1893. Soon after, the French company Metropole marketed their Acatane. By 1897 Columbia began aggressively to market the chainless bicycle it had acquired from the League Cycle Company. Chainless bicycles were moderately popular in 1898 and 1899, although sales were still much smaller than regular bicycles, primarily due to the high cost. The bikes were also somewhat less efficient than regular bicycles: there was roughly an 8 percent loss in the gearing, in part due to limited manufacturing technology at the time. The rear wheel was also more difficult to remove to change flats. Many of these deficiencies have been overcome in the past century.

                 In 1902, The Hill-Climber Bicycle Mfg. Company sold a three-speed shaft-driven bicycle in which the shifting was implemented with three sets of bevel gears. While a small number of chainless bicycles were available, for the most part, shaft-driven bicycles disappeared from view for most of the 20th century. There is, however, still a niche market for chainless bikes, especially for commuters, and there is a number of manufacturers who offer them either as part of a larger range or as a primary specialization. A notable example is Biomega in Denmark.

                                                                                                                                                                        

1.3 Use of drive shaft

                 The torque that is produced from the pedal and transmission must be transferred to the rear wheels to push the vehicle forward and reverse. The drive shaft must provide a smooth, uninterrupted flow of power to the axles. The drive shaft and differential are used to transfer this torque.

      

               

                                         1.2.1 Drive shaft

1.3.1 Functions of the Drive Shaft

1. First, it must transmit torque from the transmission to the foot pedal.

2. During the operation, it is necessary to transmit maximum low-gear torque developed by the pedal.

3. The drive shafts must also be capable of rotating at the very fast speeds required  by the vehicle.

4. The drive shaft must also operate through constantly changing angles between     the transmission, the differential and the axles.

 

1.4 Comparison of Shaft vs. Chain

                    Basically in two wheelers, the energy transmitted by chain sprocket and gear teeth  mechanism. But in chain & sprocket case of transmission only 81% of power is  transmitted to the wheel, where remaining 19% of the energy is lost in form  energy loses (traction in gears and less tension in chain). And in this case, regular  lubrication is required in chain transmission. Regular watering over chain will  reduce the viscosity of the lubricant of the chain. Conversely , the chain may get  damaged. This avoid the usage of chain and sprocket method of transmission.  Dynamic two-wheelers claims that a drive shaft two-wheelers can deliver 94%  efficiency and it has more consistent performance. The engineering of interests  discussed are related to the design and methodology of Shaft and bevel gears.

CHAPTER 2

LITERATURE REVIEW

                        A shaft-driven two wheeler is a tandem that uses a solid shaft as an alternative of a chain to transmit power from the engine to the wheel. But were mostly supplanted by chain-driven tandem due to the cog ranges possible with sprockets and chain. Freshly, due to advancements in internal cog knowledge, a small number of up-to-the-minute shaft-driven two wheelers has been introduced.  Shaft-driven bikes have a large Bevel cogs where a conventional bike would have  its chain ring. This meshes with an additional bevel cog mounted on the drive  shaft. The use of bevel cogs allows the bloc of the drive torque from the engine  to be crooked through 90 degrees.

                       The drive shaft then has another bevel cog near the rear wheel hub which    meshes with a bevel gear on the hub where the rear sprocket would be on a predictable  bike, and cancelling out the foremost drive torque change of axis. Shaft drive is as close to maintenance-free as any motorcycle drive system can be. With the exception of the very popular, belt drive touring models, you will seldom find dedicated sport-touring or luxury touring bikes without that alloy case in the  rear wheel hub, despite the additional cost, weight and complexity.

                   The 90-degree change of the drive plane that occurs at the substructure cohort and again at the rear hub uses bevel cogs for the most well-organized concert though   other mechanisms could be used. The drive shaft is often mated to a hub cogs   which is an internal cog arrangement housed inside the rear hub.

CHAPTER 3

COMPONENTS OF BICYCLE

3.1 Paddle

                 A bicycle pedal is the part of a bicycle that the rider pushes with their foot to  propel the bicycle. It provides the connection between the cyclist's foot or shoe and  the crank allowing the leg to turn the bottom bracket spindle and propel the  bicycle's wheels. Pedals usually consist of a spindle that threads into the end of the  crank and a body, on which the foot rests or is attached, that is free to rotate on  bearings with respect to the spindle. Part attached to crank that cyclist rotate to  provide the bicycle power; it consists of three segments.

3.1.1 Paddle

3.2 Hub

                 Centre part of the wheel from which spoke radiate, inside the hub are ball bearings  enabling to rotate around in axle. It is made up of mild steel.

3.3 Bevel gear

                 A kind of gear in which the two wheels working together lie in different planes and  have their teeth cut at right angles to the surfaces of two cones whose apices    coincide with the point where the axes of the wheels would meet.

                                                              3.3.1 bevel gear

3.4 Driven Shaft

                 A shaft-driven bicycle is a bicycle that uses a drive shaft instead of a chain to transmit power from the pedals to the wheel. Shaft drives were introduced over a  century ago, but were mostly supplanted by chain-driven bicycles due to the gear  ranges possible with sprockets and derailleurs. Recently, due to advancements  in   internal gear technology, a small number of modern shaft-driven bicycles have been  introduced.

3.5 Merits of Drive Shaft

1. They have high specific modulus and strength.

2. Reduced weight.

3. Due to the weight reduction, energy consumption will be reduced.

4. They have high damping capacity hence they produce less vibration and noise.

5. They have good corrosion resistance.

6. Greater torque capacity than steel or aluminum shaft.

3.6 Brakes

                    Bicycle brakes may be rim brakes, in which friction pads are compressed against the wheel rims; hub brakes, where the mechanism is contained within the wheel hub, or disc brakes, where pads act on a rotor attached to the hub. Most road bicycles use rim brakes, but some use disk brakes. 

                              Disc brakes are more common for mountain bikes, tandems and recumbent bicycles than on other types of bicycles, due to their increased power, coupled with an increased weight and complexity. With hand-operated brakes, force is applied to brake levers mounted on the handlebars and transmitted via Bowden cables or hydraulic lines to the friction pads, which apply pressure to the braking surface, causing friction which slows the bicycle down.

3.7 Wheels and tires

                 The wheel axle fits into fork ends in the frame and fork. A pair of wheels may be called a wheel set, especially in the context of ready-built "off the shelf", performance-oriented wheels.

                Tires vary enormously depending on their intended purpose. Road bicycles use tires 18 to 25 millimeters wide, most often completely smooth, or slick, and inflated to high pressure in order to roll fast on smooth surfaces. Off-road tires are usually between 38 and 64 mm (1.5 and 2.5 in) wide, and have treads for gripping in muddy conditions or metal studs for ice.

SL.NO	COMPONENT	MATERIAL
1	Shaft	Mild steel
2	Hub	Cast iron
3	Bevel gears	Cast iron
4	Support	Mild steel

3.1.1 Materials for components

CHAPTER 4

SELECTION OF METHODOLOGY

4.1 Selection of Bevel Gear

                        Bevel gears are gears where the axes of the two shafts intersect and the tooth- Bearing faces of the gears themselves are conically shaped. Bevel gears are most often mounted on shafts that are 90 degrees apart, but can be designed to work at  other angles as well. The pitch surface of bevel gears is a cone. The pitch surface of a gear is the imaginary toothless surface that you would have by averaging out  the peaks and valleys of the individual teeth. The pitch surface of an ordinary gear  is the shape of a cylinder. The pitch angle of a gear is the angle between the face  of the pitch surface and the axis. The most familiar kinds of bevel gears have pitch  angles of less than 90 degrees and therefore are cone-shaped. This type of bevel  gear is called external because the gear teeth point outward. The pitch surfaces of  meshed external bevel gears are coaxial with the gear shafts; the apexes of the two  surfaces are at the point of intersection of the shaft axes.

      4.1.1 selection of bevel gear

4.2 Selection of Drive shaft

                  In our project, the solid shaft is use to transmit the power from peddle to rear wheel.

                                     

        4.2.1 Selection of drive shaft

4.3 Selection of Axle

                 Axle is used in the peddle hub and rear wheel hub. The two ends of the axle is threaded for the purpose of to hold the objects.

                                     

4.3.1 Selection of axle

                            

4.4 Placing of bevel gear

                                                                                      

                 There are two set of bevel gears are used in this method. One pair is set in the pedal arrangement. Another set is placed in the rear wheel hub arrangement.    

                            

4.4.1placing of bevel gear

                        

4.5 Suspension

                 Bicycle suspension refers to the system or systems used to suspend the rider and all or part of the bicycle. This serves two purposes: to keep the wheels in continuous contact with the ground, improving control, and to isolate the rider and luggage from jarring due to rough surfaces, improving comfort.

                 Bicycle suspensions are used primarily on mountain bicycles, but are also common on hybrid bicycles, as they can help deal with problematic vibration from poor  surfaces. Suspension is especially important on recumbent bicycles, since while an upright bicycle rider can stand on the pedals to achieve some of the benefits of suspension, a recumbent rider cannot.

                Basic mountain bicycles and hybrids usually have front suspension only, whilst more sophisticated ones also have rear suspension. Road bicycles tend to have no suspension, due to weight and stiffness concerns, although they may have special designs to increase compliance.

4.6 Working

               As we discussed in earlier that the working principle of shaft driven bicycle is simple. The power is given to the pinion gear by the rotation of the paddle manually by the human. The power from the pinion gear is transmitted to the driven gear with the help of the driven shaft (solid shaft). The driven gear is connects to the rear wheel of the bicycle, which drives the vehicle to move forward.

                            

4.6.1 Construction of shaft driven bicycle

                    

5. CONSTRUCTION AND WORKING PRINCIPLE

                 We are concerning to use mild steel in bevel cogs and drive shaft mechanized    development. The mechanical properties of the materials used in the project arefollowing in the table5.1

SL.No	Mech.Properties	Symbol	Units	Cast Iron
1.	Young’s Modulus	E	GPa	105.0
2.	Shear Modulus	G	Gpa	36.75
3.	Poisson Ratio	µ	-	0.23
4.	Density	ρ	Kg/m3	7209
5.	Yield Strength	Sy	MPa	130
6.	Shear Strength	Ss	MPa	169

                    

Table 5.1.1 Mechanical properties of Cast iron

                The term Drive shaft is used to refer to a shaft, which is used for the transfer of motion from one point to another. Whereas the shafts, which propel is referred to as the propeller shafts. However the drive shaft of the automobile is also referred to as the propeller shaft because apart from transmitting the rotary motion from the front end to the rear end of the vehicle, these shafts also propel the vehicle forward. The shaft is the primary connection between the front and the rear end, which performs both the jobs of  transmitting the motion and propelling the front end. The design of drive shaft.

                Thus the terms Drive Shaft and Propeller Shafts are used interchangeably. In other words, a drive shaft is a longitudinal power transmitting, used in vehicle where the pedal is situated at the human feet. A drive shaft is an assembly of one or more  solid shafts connected by universal, constant velocity or flexible joints. The number of tubular pieces and joints depends on the distance between the two wheels. The job involved is the design for suitable propeller shaft and replacement of chain drive smoothly to transmit power from the pedal to the wheel without slip. It needs only a less maintenance. It is cost effective. Propeller shaft strength is more and also propeller shaft diameter is less. it absorbs the shock. Because the propeller shaft center is fitted with the universal joint is a flexible joint. It turns into any angular position. The both end of the shaft are fitted with the bevel pinion, the bevel pinion engaged with the crown and power is transmitted to the rear wheel through the propeller shaft and gear box. . With our shaft drive bikes,there is no more grease on your hands or your clothes; and no more chain and derailleur maintenance.

5.1 Specification of drive shaft

                 The specifications of the composite drive shaft of an automotive transmission are  same as that of the steel drive shaft for optimal design. The material properties of the steel (SM45C) are given in Table. The steel drive shaft should satisfy three design specifications such as torque transmission capability, buckling torque capability and bending natural frequency.

5.2 Design Assumptions

1. The shaft rotates at a constant speed about its longitudinal axis.

2. The shaft has a uniform, circular cross section.

3. The shaft is perfectly balanced, i.e., at every cross section, the mass center

Coincides with the Geometric center.

4. All damping and nonlinear effects are excluded.

5. The stress-strain relationship for composite material is linear & elastic; hence,

Hook’s law is Applicable for composite materials.

6. Acoustical fluid interactions are neglected, i.e., the shaft is assumed to be acting

in a vacuum.

7. Since lamina is thin and no out-of-plane loads are applied, it is considered asunder the plane Stress.

5.3 Advantages

1.     Drive system is less likely to become jammed or broken, a common problem with chain-driven bicycles.

2.     The use of a gear system creates a smoother and more consistent pedaling

motion.

3.     The rider cannot become dirtied from chain grease or injured by the chain from "Chain bite", which occurs when clothing or even a body part catches between the chain and a sprocket.

4.     Lower maintenance than a chain system when the drive shaft is enclosed in a tube, the common convention.

5.     More consistent performance. Dynamic Bicycles claims that a drive shaft bicycle consistently delivers 94%efficiency, whereas a chain-driven bike can deliver anywhere from 75-97% efficiency based on condition.

6.     Greater clearance: with the absence of a derailleur or other low-hanging machinery, the bicycle has nearly twice the ground clearance.

7.     For bicycle rental companies, a drive-shaft bicycle is less prone to be stolen, since the shaft is non-standard, and both noticeable and non-maintainable.

8.     This type of bicycle is in use in several major cities of Europe, where there have been large municipal funded, public (and automatic) bicycle rental projects.

5.4 Disadvantages

1.   A drive shaft system weighs more than a chain system, usually 1-2 pounds heavier.

2.   At optimum upkeep, a chain delivers greater efficiency.

3.   Many of the advantages claimed by drive shaft's proponents can be achieved on a chain-driven bicycle, such as covering the chain and gears with a metal or plastic cover.

4.   Use of lightweight derailleur gears with a high number of ratios is impossible, although hub gears can be used.

5.   Wheel removal can be complicated in some designs (as it is for some chain-driven bicycles with hub gears).

5.5 Design calculation

Drive shaft

          Shaft length = 0.47m

          Diameter     = 0.18m

Bevel gear

          Gear pitch P = MT/2

                             = 0.008 *17/2

                             = 0.068m

          Module (m) = 0.008m

                  

CHAPTER 6

CONCLUSION

                   Firstly the project were unable to be completed with the drive shaft due to various problems around circumference of the bicycle, later on this was realized to run successfully with two bevel gears at both end of the drive shaft. The presented work was aimed to reduce the wastage of human power (energy) on bicycle riding or any machine, which employs drive shafts; in general it is achieved by using light weight drive shaft with bevel gears on both sides designed on replacing chain transmission The presented work also deals with design optimization i.e. converting rotary motion in linear motion with aid of two bevel gears.

                 Instead of chain drive one piece drive shaft for rear wheel drive bicycle have been optimally designed and manufactured for easily power transmission. The drive shaft with the objective of minimization of weight of shaft which was subjected to the constraints such as torque transmission, torsion buckling capacity, stress, strain, etc. The torque transmission capacity of the bicycle drive shaft has been calculated by neglecting and considering the effect of centrifugal forces and it has been observed that centrifugal force will reduce the torque transmission capacity of the shaft. The stress distribution and the maximum deformation in the drive shaft are the functions of the stacking of material. The optimum stacking of material layers can be used as the effective tool to reduce weight and stress acting on the drive shaft. The design of drive shaft is critical as it is subjected to combined loads. The designer has two options for designing the drive shaft whether to select solid or hollow shaft. The solid shaft gives a maximum value of torque transmission but at same time due to increase in weight of shaft. The results obtained from this work is an useful approximation to help in the earlier stages of the development, saving development time and helping in the decision making process to optimize a design. The drive shaft has served as an alternative to a chain-drive in bicycles for the past century, never becoming very popular.

6.1 Scope of improvement

                When abnormal vibrations or noises are detected in the driveshaft area, this chart can be used to help diagnose possible causes. Remember that other components such as wheels, tires, rear axle and suspension can also produce similar conditions.

Problem	Caused by	What to do
As bicycle is accelerated from stop	Torque is required	Apply more torque at starting
when gears are not shifting	Rusting	Clean with fluids
Vibration at speed	High speed	Maintain low speed
Noise at low speed	Universal joint	Apply grease
Gears pitch circle is not coincide	Vibrations	Adjust the position of gears
Gear backlash	Noise, Overloading, Overheating	Follow design characteristics

           

           6.1 scope of improvement

6.2 Cost analysis

S. No	Description	Amount
1.	Tire, Tube, Rim	1000.00
2.	Frame, seat, brake	1000.00
3.	Lathe operations	1000.00
4..	gears	500.00
5..	welding	500.00
6.	Labor charge	500.00
7.	Solid shaft	250.00
8.	hub	250.00
	Total	5000.00

6.2 cost analysis

6.3 Reference

1. Rastogi, N. (2004). Design of composite drive shafts for automotive applications. Visteon Corporation, SAE technical paper series.

2. 73332270 Design and Analysis of a Propeller Shaft of a Toyota Qualis by “Syed Hasan”.

3. A. M. Ummuhaani and Dr. P. Sadagopan “Design, Fabrication and Stress Analysis of a Composite Propeller Shaft, 2011-28-0013.

4. Anup A. Bijagare, P.G. Mehar and V.N. Mujbaile “Design Optimization & Analysis of Drive Shaft”, Vol. 2 (6), 2012, 210-215.

5. Rangaswamy, T.; Vijayrangan S. (2005). Optimal sizing and stacking sequence of composite drive shafts. Materials science, Vol. 11 No 2., India.

6. Rastogi, N. (2004). Design of composite drive shafts for automotive applications. Visteon Corporation, SAE technical paper series.

WEBSITE REFERENCES

1. www.google.in

2. Dynamic bicycles.com

3. www.engineeringtoolbox.com

4. Makeitform.com

5. Convertunits.com

6. Webbicycle.netpaths.net/technology. php

BOOKS

1. “Design Data”- Data book of engineering.

2. Machine design – Design data book

3. Strength of material by R.S Kurmi

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