Theory of Machines: Unit II: Gears and Gear Trains

length of arc of contact

Gears and Gear Trains - Theory of Machines

The length of arc of contact is the length of arc made by a point on the pitch circle from beginning to the end of engagement of both pair.

LENGTH OF ARC OF CONTACT

The length of arc of contact is the length of arc made by a point on the pitch circle from beginning to the end of engagement of both pair.

In Fig.4.24, the engagement of teeth starts at point E and ends at point F. Points E and F are located on pitch circle of pinion. So arc EPF or GPH is the arc of contact. Arc GP and PH are known as the arc of approach and arc of recess respectively.

The angles subtended by arc of approach and arc of recess at O1 are called angle of approach and angle of recess respectively.


From the geometry of Fig.4.24,

Length of arc of approach (arc GP)


and length of arc of recess (arc PH)


⸫ Length of arc of contact = Length of arc of approach + Length of arc of recess



Theory of Machines: Unit II: Gears and Gear Trains : Tag: : Gears and Gear Trains - Theory of Machines - length of arc of contact