Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Material used: Ropes are commonly made of cotton, manila or hemp.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
When a belt is trapezoidal in section, designed to run in a V-shaped groove, it is known as a V-belt.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
The tension of the belt when a belt is fitted to a pair of pulleys when the system is stationary, is termed as initial tension of the belt.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
For maximum power, differentiate the above expression with respect to v and equate to zero.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Since the belt continuously runs over the pulley, therefore some centrifugal force is caused.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Consider a belt drive, as shown in Fig.8.20.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
The belt drives primarily operate on the friction principle. That is, the friction between the belt and the pulley is responsible for transmitting power from one pulley to the other.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Length of belt can be determined practically as well as mathematically.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Consider a compound belt drive, as shown in Fig.8.16. In Fig.8.16, pulley 1 drives the pulley 2; pulleys 2 and 3 are keyed on the same shaft; thereby pulley 3 drives pulley 4.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Presence of friction between pulley and belt causes differential tension in the belt.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Slip is defined as the relative motion between the belt and pulley due to insufficient friction between bolt and pulley.
Friction in Machine Elements - Theory of Machines
Subject and UNIT: Theory of Machines: Unit III: Friction in Machine Elements
Definition: Velocity ratio is the ratio of the velocity of the driven pulley to the velocity of the driver pulley.