BELTS

PRESENTED BY:

MAYANK RAWAT

AUTOMOBILE(ME-C)

SEMINAR REPORT ON

INTRODUCTION

BELTS ARE USED TO TRANSMIT POWER FROM ONE SHAFT TO ANOTHER SHAFT BY MEANS OF PULLEYS WHICH ROTATES AT SAME SPEED OR DIFFERENT SPEED EITHER IN SAME DIRECTION OR IN DIFFERENT DIRECTION.

TYPES OF BELT1) V-belt: these are trapezoidal shape belts which are mounted

over gorove in the rim of pulley.

2) Flat belt: these belts have rectangular section and are mounted over pulley whose rim is slightly crowned.

3) Circular belt or rope: these belts are generally circular in shape and the pulley used have a grooved circumference.

MATERIAL USED FOR BELTS

1) Leather belts

2) Cotton or fabric belts

3) Rubber belts

4) Balata belts

TYPES OF FLAT BELT DRIVE

1) Open belt drive

2) Crossed belt drive

3) Compound belt drive

4) Quarter turn belt drive

5) Belt drive with idler pulley

6) Stepped or cone pulley drive

VELOCITY RATIO OF BELT DRIVE

The ratio of velocities of driver and follower or the driven is known as velocity ratio of belt drive.

Where speed of driver and follower

dia of driver and follower

T = thickness of belt

=

SLIP OF BELT

When there is insufficient friction between the pulley and the belt causing the forward motion of the belt without carrying the driven pulley with it is called slip of belt.

the factors could be various such as

1) Friction between rim of pulley and belt.

2) Linear speed of pulley and belt.

To reduce it just tight the belt or replace it.

LENGTH OF OPEN BELT DRIVE

Open belt drive when both drives are moving in same direction.

L()+2x+

LENGTH OF CROSS BELT DRIVE

CROSS BELT DRIVE WHEN BOTH DRIVES ARE MOVING IN OPPOSITE DIRECTION.

L=

POWER TRANSMITTED BY BELTS

If tension in tight and slack side of belt respectively

radii of driver and follower respectively

velocity of belt

Then,formula for power

ANGLE OF CONTACT

The angle which the belt makes around its circumference when it is in contact with the pulley.

When solving problems the angle of contact of smaller pulley should be taken into consideration.

For open belt drive,

rad

For cross belt drive,

rad

RATIO OF DRIVING TENSION IN FLAT BELT DRIVE

If is tension on belt of tight side

is tension on belt of slack side

is angle of contact

Then the ratio is as follows:

APPLICATION

You see them on HVAC applications, like air handlers. Typical is an electric motor belt hooked up to a fan or maybe a conveyor belt. Rock quarries, huge exhaust fans, grain elevators, dryers.

And of course back up generators like those with big diesel engines.

And those old school saw mills you see at the State Fair that are hooked up to a coal fired steam engine.

THANK YOU