COMPONENTS OF CRANKSHAFT

Group Members

Muhammad Talha Farooq (14-ME-123) Muhammad Talha Rasheed (14-ME-124) Muhammad Talha Sherwani (14-ME-125) Muhammad Tariq Nadeem (14-ME-127)

What is Crankshaft?

It is a shaft which transmits the power developed by the engine to the various parts of the vehicle.

It is a link between the input and output of the vehicle. Without crankshaft your vehicle won't even move an inch though your engine will be running.

Types of Crankshaft Same plane

Cross plane

Types of Crankshaft

Single Throw Crankshaft Double Throw Crankshaft Four Throw Crankshaft Six Throw Crankshaft

Function of Crankshaft Changes reciprocating motion of piston into rotating motion

to drive propeller. Constructed of chrome-nikel-molydenum-steel. The propeller is mounted the front of crankshaft using a

spline, taper or flange. Crankshaft rotates within the crankcase and is supported by

main bearing journals.

Parts of Crankshaft

Crank Shaft

Web

 The portion of a crank between the crankpin and the shaft or between adjacent crankpins —called also crank arm, crank throw

Counter Weight Crankshaft counterweights are designed to offset (or balance) the

inertia effect of a relatively heavy piston and connecting rod moving in both a rotational and reciprocating (up-and-down) fashion. The weight of the piston and connecting rod combination affects the size and placement of the counterweight.

If this is not done, the engine will experience vibrations that will eventually tear up the main bearings and cause damage.

Crankshaft counter weights are needed to statically and dynamically balance the crankshaft.Without them, the vibrations caused will destroy it.

Crank journals

In a reciprocating engine, the crankpins, also known as crank journals are the journals of the big end bearings, at the ends of the connecting rods opposite to the piston.

If the engine has a crankshaft, then the crank pins are the journals of the off-centre bearings of the crankshaft. In a beam engine, the single crank pin is mounted on the flywheel

In a steam locomotive, the crank pins are often mounted directly on the driving wheels.

Big End Bearings

Main bearings

In a piston engine, the main bearings are the bearing on which the crankshaft rotates, usually plain or journal bearings. The bearings hold the crankshaft in place and prevent the forces created by the piston and transmitted to the crankshaft by the connecting rods from dislodging the crankshaft, instead forcing the crank to convert the reciprocating movement into rotation.

Main Bearings

Conclusion

Crankshaft serves as important part of an engine in avoiding vibrational motion and it allows smooth transmission of power from engine to various parts. Conversion of reciprocatory motion to rotational motion was made possible using crankshaft.

Reference Links

https://www.quora.com/What-is-a-crankshaft http://www.onallcylinders.com/2015/01/15/cross-plane-vs-flat-plane-crankshafts/