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DRIVE TRAIN

• Gear shifter system

• Chain Drive

• Differential assembly

• Rear axle

PARTS CONSTITUTING THE DRIVE TRAIN

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• To make a reliable and efficient Transmission system.

• For achieving better acceleration.

• Faster, accurate gear shifts and higher driver safety and comfort.

GOALS

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GEAR SHIFTER SYSTEM

• To achieve shifts within 200ms while it takes 1.5s manually.

• Better steering handling due to paddle shifts.

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GOALS

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Pneumatic gear shifter Pneumatic clutch for downshifting

Air source adaptor 1

Air source adaptor 2

In-line pressure regulator

SolenoidGear actuating cylinder

Clutch actuating cylinder

FLOW OF HPA (High pressure air) :

PNEUMATICS

Pneumatic tank

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PRIMARY GEAR SHIFTING CIRCUIT

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THEORETICAL POSSIBLE NUMBER OF SHIFTS

CALCULATIONS

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DOUBLE ACTUATING CYLINDER:

A 25x25 mm cylinder, sponsored by FESTO with max pressure rating of 10bar actuates the whole mechanism.

REED SENSOR:

They are proximity sensor with a range of 10mm used to sense piston position and control the solenoid valves.

PARTS

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SOLENOID VALVES:

Solenoid valves are like gates that allow or stop the flow of air to the cylinder. They are the last component before the cylinder.

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AIR SOURCE ADAPTERS:

2 ASA’s helps to completely remove or supply the air to the circuit as and when needed.

COMPRESSED AIR TANK:

Carbon fiber tank of 5000psi rating will store 1.7litre of compressed gas and acts as the reservoir of the circuit.

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INLINE REGULATOR :

A purely mechanical device accurately regulates the flow of air in the circuit. Made of aluminum, it holds one of the 2 ASA’s at one end.

PRESSURE GAUGE:

FESTO sponsored gauge with 10bar rating reads the air pressure in the circuit.

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TUBING, JOINTS, PUSH-IN FITTINGS:

High pressure polyurethane tubing's, NPT threaded push in fittings, nipple connectors to complete the circuit.

• Gear shifter rotates clockwise/anti clockwise and once at final position, the return spring pushes it back to initial position.

• Non flammable gas, compressed natural air was chosen over carbon dioxide due to its excessive supercritical behavior.

• Two 3/2 solenoid valves control the air flow to the piston as per signals received from the Reed sensors at 3 positions namely- Neutral, Upshift & Downshift.

• A total of 5000 shifts(theoretically) each within 240ms were obtained using FESTO simulations.

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PNEUMATIC SHIFTING

VARIATION IN CARBON DIOXIDE

SUPERCRITICAL NATURE:

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CHAIN DRIVE

• To achieve total weight under 3kg.

• 75m straight acceleration under 4.5seconds.

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GOALS

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DESIGN DECISION REASONS

Final Drive Ratio 3.692 To get optimal acceleration and top speed.

Sprocket used 13/48 • 13 teeth sprocket is available in stock for HONDA CBR 600RR.

• The odd even pairing of the sprockets leads to uniform wearing of the chain thus resulting in longer chain life.

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Ricardo-wave used to simulate acceleration times.

ENGINE SIMULATIONS

DESIGN DECISION REASONS

The chain selected is a 520 series DID X-ring chain

• It has a rating of 38.5KN in tension and weight of 1.5kg/100 links.

• X rings are self lubricated, the need for casing around the chain for greasing is avoided.

Angle Wrap =125

Min centre distance =197mm• This gives Proper grip chain over the sprocket and

transfers power without any losses.

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SPROCKET

NUMBER OF TEETH

MATERIAL WEIGHT

Driving 13 655M13 Ni-Cr-Mo alloy steel 146 grams

Driven 48 Al 7075, case hardened up to T6 450 grams

SPROCKETS

MATERIAL PROPERTIES OF

DRIVEN SPROCKET

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DENSITY 2.180GM/ CC

Ultimate tensile strength 572MPa

Yield strength503MPa

Minimum Wrap angle125 deg.

Maximum engine Torque = 65 Nm

Primary gear reduction = 2.111

First gear ratio = 2.66

Final drive ratio = 3.69

Maximum Torque faced by sprocket = 65*2.111*2.66*3.69 = 1346.82 Nm

Diameter of the sprocket = 242.72mmForce acting on the sprocket = 1346.82/0.12136 = 11097.73 N

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SPROCKET CALCULATIONS

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FEA DRIVEN SPROCKET

• Maximum displacement = 0.0352mm28

FEA DRIVEN SPROCKET

Complying with FSAE competition rules, the shield is; • Made of mild steel.• Covers the chain from drive to driven sprocket.• More than 3 times the max width of the chain(18mm).• In lateral alignment with each other.• Protects the brake lines from the chain.

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SCATTER SHIELD

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DRIVELINE ASSEMBLY

• Chain tensioning mechanism that allows 10/8” of chain tightening.

• The axis of mounting should be as close as possible to the wheelbase, to avoid large angles at tripod.

• The design should not have any mounting points on Rear bulk head.

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GOALS

DREXLER LSD DIFFERENTIAL

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DIFFERENTIAL

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FM XI FM 2013

Taylor Quaife Differential Drexler LSD Differential

Torsen (torque sensing) Clutch Type LSD (Limited slip differential

Weight= 5kg Weight= 2.5kg

Fixed TBR( Torque biasing ratio)= 4:1 6 different Torque biasing ratio

DIFFERENTIAL COMPARISON

GOALS

• To tension the chain accurately by 2 pitch lengths of the chain.

• Reliable tensioning method, so as to avoid slipping of chain during events.

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CHAIN TENSIONER

DESIGN CONSIDERATIONS REASONS

Rotate eccentric disk 180 degree with differential axis at 10 mm offset to the eccentric axis

To achieve chain tensioning of 10/8 inches with eccentric disk as small as possible.

Material-Aluminium 7075 T6Light weight

Manufacturing-Laser cutHigh accuracy

ECCENTRIC DISKS

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ECCENTRIC DISC

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DIFFERENTIAL MOUNTING

• The rear bulk head is removed and thus mountings will be mounted on the engine mounting points.

• It should be able to incorporate eccentric disk(chain tensioning).

• Should be light weight and as close as possible to wheel base to avoid large angles at tripod joints.

• It should be light and equally strong to withstand vibrational and torsional loads.

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GOALS

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DESIGN CONSIDERATIONS REASONS

C shape mount is designed This will help in removing Rear bulk head.

Outer most diameter of the mounting is 145mm.

It should incorporate eccentric disk.

Material - Aluminium 7075 T6 Light weight and easy available

Manufacturing: CNC millingAvailability and accuracy

DESIGN

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DIFFERENTIAL MOUNT

With Eccentric Disk

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DIFFERENTIAL MOUNTS CALCULATIONS

• From the sprocket calculations the force

• on the sprocket = 11097.73 N

• Due to the position of the mounting points the differential mounts assembly will act as an over hanging beam.

• The total force acting on the sprocket is the force acting on the differential mountings.

• Reaction on mounting A + Reaction on mounting B=11097.73

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Reaction on A + Reaction on B = 11097.73 N

Moment about mounting B will be

11097.73*220 = Ra*175

Ra = 13951.432 N Rb = -2853.702 N

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FEA OF LEFT DIFFERENTIAL MOUNTING

MAXIMUM STRESS

209.7 MPa

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MAXIMUM DEFLECTION

0.31502 mm

FEA OF LEFT DIFFERENTIAL MOUNTING

FEA OF OUTER STUB AXLE

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MAXIMUM STRESS

1378.8 Mpa

FEA OF OUTER STUB AXLE

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MAXIMUM DEFLECTION

0.41018 mm

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FEA OF INNER STUB AXLE

MAXIMUM STRESS

921.26 MPa

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FEA OF INNER STUB AXLE

MAXIMUM DEFLECTION

0.45885 mm

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The bearings used are SKF bearings of the following specifications:

SERIES SPECIFICATIONS

6010

• ID – 50mm

• OD – 80mm• Thickness – 16mm

6011

• ID – 55mm• OD – 90mm• Thickness – 18mm

BEARINGS

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Designs FM XI FM 2013

Pneumatic shifting Time for gear shift=1.5 sec Time for gear shift= 250ms

Differential Weight= 5Kg Weight= 2.5 Kg

Chain tensioner Rod ends Eccentric disk (accurate)

Left differential Mounting 779 grams 900 grams without eccentric

Right Differential Mounting 779grams 680 grams without eccentric

COMPARISON

Total Weight Reduction = 2.478 Kg