Refrigeration & Equipment Engineering

Unit 7 - Power transmission elements

7.4.1.Shaft
A shaft is a rotating machine element which is used to transmit power from one place to another. The power is delivered to the shaft by some tangential force and the resultant forgue or forsional moment set up within the ;shaft permits the power to be transferred to various machines linked up to the shaft. In order to transmit the power from one shaft another, the various members such as pulleys, gears etc. are mounted on it. These members along with the forces exerted upon them causes the shaft to bending. In other words, we may say that a shaft is used for the transmission of torque and bending moment.

Types of shafts

• Transmission shafts: Transmission shafts transmit power between the source and the machines absorbing power. The counter shaft, line shafts, overhead shafts and all factory shafts are transmission shafts. Since these shafts carry machine parts such as pulleys, gears etc. therefore they are subjected to bending in addition to twisting.
• Machine shafts: These shafts form an integral part of machine itself. The crankshaft is an example of machine shaft.