modified spokeless bicycle wheel

8/22/2019 Modified Spokeless Bicycle Wheel

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By

Shailendra Chauhan(A2305410254)Tushar Thakkar(A2305410175)

Indraneel Dutta(A2305410176)

Ravin Kumar(A2305410177)

Faculty Guide: Mr. Rajan Raman Vishwambaram


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Bicycle which has been the most simple,ecofriendly and an economical mode oftransport is an engineering marvel for

wonderful innovations.


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PARTS OF THE WHEEL The Frame.

Drive Train and gearing.

Brakes. Suspension.

Wheels and Tyres.


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THE FRAMEThe structure of the frame is more aerodynamic than

upright versions.

The rider may lean back onto a support and operatepedals that are on about the same level as the seat.

The goal for the material selection is low weight andhigh strength.

Analogous to the proposed bicycle frame, the modelconsists of wood frame rather than the proposed 6101Al alloy.


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Drive train and gearingWith a chain drive transmission, a chain ring attached to a crank

drives the chain, which in turn rotates the rear wheel via the rearsprocket(s) (cassette or freewheel).

There are four gearing options: two-speed hub gear integrated

with chain ring, up to 3 chain rings, up to 11 sprockets, hub gearbuilt in to rear wheel (3-speed to 14-speed). The most common options are either a rear hub or multiple

chain rings combined with multiple sprockets .With a shaft drive transmission, a gear set at the bottom bracket

turns the shaft, which then turns the rear wheel via a gear setconnected to the wheel's hub. There is some small loss of efficiency due to the two gear sets

needed. The only gearing option with a shaft drive is to use a hubgear.


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BRAKES With hand-operated brakes, force is applied to brake levers

mounted on the handlebars and transmitted via Bowden cablesor hydraulic lines to the friction pads.

Brakes are not required for riding on a track because all riders

ride in the same direction around a track which does notnecessitate sharp deceleration. Track riders are still able to slowdown because all track bicycles are fixed-gear, meaning thatthere is no freewheel. Without a freewheel, coasting isimpossible, so when the rear wheel is moving, the crank ismoving.

To slow down, the rider applies resistance to the pedals

thisacts as a braking system which can be as effective as a frictionbased rear wheel brake, but not as effective as a front wheelbrake.


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SUSPENSION Bicycle suspension refers to the system or systems used

to suspendthe rider and all or part of the bicycle.

This serves two purposes, to keep the wheels incontinuous contact with rough surfaces to improvecontrol and to isolate the rider and luggage fromjarring due to rough surfaces.

Suspension is especially important on recumbentbicycles, since while an upright bicycle rider can standon the pedals to achieve some of the benefits ofsuspension, a recumbent rider cannot .


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Wheels and tyres

In conventional bicycles, the entire central portion of the wheelstructure, extending from the centered axle to the outer perimeter ortire-mounting rim may be of a specialized design having high aestheticappeal.

The above and other beneficial objects and advantages areaccomplished in accordance with the present invention by a metal

wheel of monolithic construction having opposed sides of equaldiameter and comprised of:

A hub having a cantered axis of rotation is removed, to accomplish theaim of providing a spokeless wheel.


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The rim is circular and the tyre tube attaches itselfwith the grip. c) Timings belt GT2 which isdemonstrated further is embedded to the rim which is

driven by the hub gear.It is a further object of this invention to provide a

wheel as in the foregoing object which secures aresilient tyre.

The wheel is supported by a wheel support of 6101 Alalloy.


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RIMRims designed for use with rim brakes provide a smooth

parallel braking surface, while rims meant for use with discbrakes or hub brakes sometimes lack this surface.

These rims cannot be used with caliper rim brakes. Thecross-section of a rim can have a wide range of geometry,each optimized for particular performance goals.

Aerodynamics, mass and moment of inertia, stiffness,durability, tubeless tire compatibility, brake compatibility,and cost are all considerations.


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4. INTERPRETITION OF COLLECTED

DATA Rear Wheel:

Outer Diameter: 40 cmsInner Diameter: 26 cms

Driving Paddle WheelDiameter (D): 20 cmsNumber of teeth (T) : 27

Sprocket WheelDiameter (d): 8 cms

Number of teeth (t): 18

Data for Chain Length Calculations:C= Centre distance between sprockets = kp = 28.3 cmsP= pitch of chain = 1.3 cms


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CALCULATIONS

where = Angle subtended by chord of a link at the centre of sprocket.

r = radius of the pitch circle

Where L= length of the chain.

C= center distance between the centres of two sprockets.

R= Radius of the Driving wheel.

r= radius of the driven sprocket.

Therefore, the length,L=1.25 m


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BRIEF DESCRIPTION OF THE

DRAWING

FIG. 1 is a front view of the embodiment of thewheel of the present invention.


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FIG. 2 is a side view as in FIG. 1 of the drive

chain attached to the spokeless wheel.


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MATERIALS REQUIREDRIM: The most economical and weight effective material (e.g.Aluminium) .

FRAME: Mild steel which should have enough strength andrigidity.

Industrial grade aluminium, nearly 16 mm and 11 mm inthickness.

The frame would be made by rectangular cross-section mild steelbars welded together.

The wheel support would be made out of 6061 Al alloy, which ischeaper compared to the aerospace version 7075. 6061 has a density of 2.70 g/cc, an ultimate strength of 310 MPa

and a yield of 276 MPa, showing about 12% strain at rupture.


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TIMING BELTA timing belt, or cam belt (informal usage), is a part of an internalcombustion engine that controls the timing of the engine's valves.

The term "timing belt" is sometimes used for the more general case of

any flat belt with integral teeth,This is not a problem unique to timing belts since the same issue existswith all other cam/crank timing methods such as gears or chains.


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Failure

A pair of valves bent by collision with a piston after

timing belt breakage. The engine was running at 4500RPM.

Its use here increases its durability.

The usual failure modes of timing belts are either

stripped teeth (which leaves a smooth section of beltwhere the drive cog will slip) or delamination andunravelling of the fibres cores.

Breakage of the belt, because of the nature of the high

tensile fibers, is uncommon.


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Correct belt tension is critical - too loose and the beltwill whip, too tight and it will whine and put excessstrain on the bearings of the cogs. In either case belt

life will be drastically shortened.Aside from the belt itself, also common is a failure of

the tensioner, and/or the various gear and idlerbearings, causing the belt to derail.


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7. APPLICATIONS

It can replace the normal spoke wheel of themotorbikes.

As the chain drive spoke wheel concept is used in cyclerickshaws the proposed wheel can be used inrickshaws too effectively increasing its speed.

The proposed wheel can be used in a drive mechanismof handicraft vehicles and many more.


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CONCLUSIONS &

RECOMMENDATIONS Will add aesthetic, trendy and appealing value to the existing transport of

the masses. Spokes which add weight to the bicycle can be effectively reduced with the

implementation of such a wheel in its design.

Material selection for the bicycle framework is still a challenge by selecting amaterial having the strength requisites to support the bicycle wheel.

Cost effectiveness and aesthetic sense is the utmost care that needs to be takenfor selection. Moreover the proposed wheel can be tested in other modes oftransport where the motive power is derived from the chain wheel mechanism.

Improvements like ratcheting resistance during high start-up torques,

Reduced bearing loads, particularly in fixed-centre drives. Lower average tensions can be used without encountering tooth jump at thelow tension end of the tolerance ranges,

Reduced system losses result from lower pre-tensioning, with less potential fortooth jumping. Nevertheless the developing of the spoke-less wheel was anuncountable experience.


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DRIVE COMPARATIVE STUDIES:Poly Chain GT Carbon :Poly Chain GT Carbon belt drives

high power transmission strength, flexibility anddurabilitymatching the capacity of roller chain drives

width-for-width in most pitch sizes. High Torque Drive (HTD) Belts are the development of

timing belts with 'curvilinear'tooth form enabling 'HighTorque Drives'.

The PowerGrip MXL belt is a classical synchronous beltwith a pitch of 0.08" (2.032 mm).It is recommended forapplications where maximum synchronisation, smallpackage and high speed are required. Space-saving andhighly stable, this belt is the ideal solution to precision

drives such as office machines and computers .Comparative studies, allow designers to make

quantitative assessments and to highlight the mostsignificant improvements and design opportunities.


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Durability:

The greatly increased durability of the Power Grip GT2design has resulted in power capacities far above thosequoted for similar size belts of previous designs. Theresulting small drive packages will increase design

flexibility, space utilization and cost effectiveness


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F ig. Tooth Jump Resistance


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The very significant improvement in tooth jumpresistance of Power Grip GT2 when compared to similarbelts has several important advantages.

1. Ratcheting resistance during high start-up torques.A ratchet is a device that allows continuous linear or rotarymotion in only one direction while preventing motion inthe opposite direction. Therefore, at high start-up torquesit resists the backward motion of wheels.

2. Reduced bearing loads, particularly in fixed-center drives.Lower average tensions can be used without encounteringtooth jump at the low tension end of the tolerance ranges.

3. Reduced system losses result from lower pre-tensioning,with less potential for tooth jumping. Therefore, it enablesproper and efficient tooth gripping without tooth jumping.


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REFERENCES[1] Bothichander T, Modified Spoke less Bicycle, Manfex 2012, 29thMarch 2012, Amity University, Noida, Uttar Pradesh

[2] Bicyclemechanichttp://www.ecofriend.org/entry/engineering-students-create-spokeless-bicycle-prototype/

[3] Design boomhttp://www.designboom.com/weblog/cat/16/view/9195/spokeless-bicycle.html howstuffworks.com/

[4] Spoke less bicycle proto typehttp://www.toxel.com/tech/2010/02/17/spokeless-bicycle-prototype/


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THANK YOU!

modified spokeless bicycle wheel

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