MECHANICAL BELTS

MECHANICAL BELTS BY G.D

1. BELTS (MECHANICAL)

2. BELT

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

4. TYPES OF BELTS FLAT BELT V-BELT ROUND BELT TIMING BELT

5. FLAT BELT

6. 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 .

7. 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  .

8. 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.

9. V BELT

10. V-BELT S olved 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.

11. 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.

12. 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

13. ROUND BELT

14. 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.

15. ADVANTAGES Used as long distance. Various lengths.

16. TIMING BELT

17. 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.

18. ADVANTAGES 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.

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

20. 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.

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