Belt drives

Classification

1. Light drive

2. Medium drive

3. Heavy drive

Types of belts

1. Flat belt
2. v-belt
3. rope or circular belt

Flat belt drives:-These belts are mostly used there when two pulleys are not more than 8 meter’s apart.

Type of flat belt drives

1. open belt drive
2. crossed belt drive

1. Open belt drive:-is used with shaft arranged parallel and driver & follower move in same direction.
2. Crossed belt drive:-drive & drives rotate in reverse direction.

Velocity ratio of belt drive:-It is the ratio of between the velocity of driven to the velocity of the driver.

Let d1=diameter of driver

n1=speed of driver in rpm

d2=diameter of follower

n2=speed of the follower in rpm

Length of the belt that passes over the driver in one minute=Πd1n1………………..1

Because 1 rotation =Πd1*length so n1 rotation = Πd1n1length

Length of the belt pass over the follower in one minute= Π d2n2…………………..2

From equation 1 & 2

Πd1n1=Πd2n2

Velocity ratio(vr)=speed of follower/speed of driver

Vr=n2/n1=d1/d2

if thickness of belt is t then vr=

n2/n1=d1+t/d2+t=r1+t/r2+t