Crankshaft

Introduction

You would have probably listened about cranking an engine, just to rotate the key’s or pressing the push button.

In this Auto tech word this means, giving an initial momentum to the combustion process by an external assistance, like a starter motor.

Crank shaft is really important to any engine/automobile as though the engine could produce the power but won’t be able to transfer the power to the transmission line.

The crankshaft is the last part of the main engine and the acts as a meditate part between the engine and the transmission system.

Crank shaft from the engine side is connected to the piston through the connecting rods, each for one piston.

The connecting rod has 2 ends, the big end is connected to the crank shaft via the gudgeon pin and the small end to the piston.

The cranks shaft is then connected to the transmission line through the flywheel attached to the crank shaft and the clutch system attached to the transmission input.

The crank shafts are usually made up of caste iron by pouring the molten metal into a mold or by forging a block of metal and hammering it red hot state into the desired shape, which is then grinded and smoothed.

Crank Shaft Main Parts

• Main Journals
• Connecting Rod Journals
• Crank Shaft Lubrication
• Counter Weights
• Crank Shaft Thrust Washers
• Main Oil Seeds
• Fatigue

Main Journals

main bearings are the bearings that supports the crankshaft in the engine bay and allow the crankshaft to rotate freely.

Connecting Rod Journals

Also termed as rod bearing journals, are the bearings to which the big end of the connecting rod is attached and rotated as an offset from the main center of rotation.

The oil is supplied through the drilled holes at an angle from the main journal.

Crank Shaft Lubrication

The mechanical components often works producing friction, and are all time exposed to successive wear and tear of the components, thus impacting the output, efficiency.

The oil of specified grade is then applied through angled drilled hole from the main journal to counter the friction.

The crankshaft subjected to high inertia forces, jerk due to rotations and also offset of the connecting rod journals collectively disturbs the rotational axis, hence to nullify these forces, external weights are added.

Crank Shaft Thrust Washers

Due to the various jerks and forces, sometimes a resultant force and also the gyroscopic force comes into play acting in the side ways direction that can if allowed so could be highly destructive.

Hence to counter the sideways action of the crank shaft weight thrusts washer are employed at multiple locations.

Main Oil Seals

These are 2 in numbers at the ends to stop the leakage of the oil from the crank shaft.

Originally published at https://www.carengineered.com on November 2, 2020.