MECHANICAL BELTS BY G.D

2. BELTS
(MECHANICAL)

3. BELT

6. VELOCITY RATIO
It is the ratio between the
velocities of the driver and the
follower or driven.
velocity ratio,N1/N2=d1/d2

9. TYPES OF BELTS
FLAT BELT
V-BELT
ROUND BELT
TIMING BELT

11. FLAT BELT

12. FLAT BELT
 Widely used.
Simple system of power transmission.
It can deliver high power at high speeds
(500 hp at 10,000 ft/min, or 373 kW at
51 m/s)
 Leather or fabric.
 Today rubber or synthetic polymers.

13. ADVANTAGES
 The flat belts are very simple in design and
cheaper.
 Smooth running and quiet running.
 Flat belts can be used for long distances, even
up to 15 m.
 They are durable.
 Fast and loose clutch action and variable output
speed .

14. DISADVANTAGES
• High Chance of slip off.
• Compared to v-belts, flat belts require
significantly greater of pretension to
transmit a certain torque without slip.
• They are bulky, for a given
transmission, flat belt drive requires a
wide pulley.
• Flat belts are not advisable for high
outputs at high speeds.

15. V BELT

16. V-BELT
• Solved the slippage and alignment
problem.
• Basic belt for power transmission.
• The “V” shape of the belt tracks in a
mating groove in the pulley (or
sheave),with the result that the belt
cannot slip off.
• The belt also tends to wedge into the
groove as the load increases.

17. ADVANTAGES OF V-BELT
High power transmission capacity
because V-grooves provide excellent
grip.
Slip between the belt and the pulley is
negligible.
The axis can be horizontal, vertical or
inclined.
They can dampen vibration.

18. DISADVANTAGES OF V-BELT
The V-belt drive cannot be used for long
distances.
The centrifugal tension prevents the use
of belts at speeds below 5 m/s and above
50 m/s.
The construction of pulleys for v-belts is
more complicated than the flat belt.
They are not applicable to the
synchronous machines

19. ROUND BELT

20. ROUND BELT
• Round belts are a circular cross section
belt designed to run in a pulley with a
circular groove.
• They are used in low torque situatons
and may be purchased in varies lengths
or cut of length and joined,either by a
stable,gluing or welding.

21. ADVANTAGES
•Used as long
distance.
•Various lengths.

22. TIMING BELT

23. TIMING BELT
Timing belts, are a positive transfer belt
and can track relative movement.
These belts have teeth that fit into a
matching toothed pulley.
When correctly tensioned, they have no
slippage, run at constant speed, and are
often used to transfer direct motion for
indexing or timing purposes.

24. ADVANTAGE
SPrecision registration and timing with
no loss of high torque carrying
capability.
Minimal vibration and chordal effect
Positive slip proof engagement
Reduced noise
High mechanical efficiency, as much
as 98% when properly maintained.

25. ADVANTAGES
Clean operation, no need for
lubrication.
Rust resistant
Weight savings
Safety issues
Long, dependable trouble-free
service

26. DISADVANTAGES
Need for accurate initial alignment of drive
components.
No slippage.
Higher drive ratios at shorter center
distances.
Lower bearing loads.
 Less affected by temperature or humidity.
Less affected by oil and grease.

28. ANY DOUBTS?
!!!