Shaft:

What is shaft? What duty is performed by shaft? What is the usual cross section and of what material it is generally made?

Sol.: The shafts are generally cylindrical in section, solid or hollow. They are made up of mild steel, alloy steel and copper alloys. Shaft can be subjected to following loads:

1. Torsional load

2. Bending load

3. Axial load

4. Combination of above three loads.

The shaft is designed on basis of strength and rigidity.

Shafts are used to transmit power from motor to pump or compressor, from the engine or turbine to generator, and from the engine to axle in automobiles. At the time of power transmission, the shaft is given torque which causes twist of shaft.

A shaft is required to be designed that the excessive twist is avoided and induced shear stress is within the prescribed limits.