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Gear trains 1.pptx

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Gear trains
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Gear trains 1.pptx

Gear Trains

Gear Trains

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Gear trains 1.pptx

1. 1. Content Gear Trains: • • Simple gear trains Compound gear trains.
2. 2. Gear Trains When two or more gears are made to mesh with each other to transmit power from one shaft to another, such a combination wheels. is called gear train or train of toothed The nature of the train, depends upon  The velocity ratio required  The relative position of the axes of shafts. A gear train may consist of spur and bevel gears.
3. 3. Types of Gear Trains Depending upon the arrangement of wheels / gears: 1. 2. Simple gear train Compound gear train
4. 4. Simple Gear Train When there is only one gear on each shaft, as shown in Fig. it is known as simple gear train. • • The gears are represented by their pitch circles. The two gears 1 and 2 transmit motion from one shaft to the other shaft. Since the gear 1 drives the gear 2, therefore gear 1 is called the driver and the gear 2 is called the driven or follower •
5. 5. Simple Gear Train The ratio of speed of the driven or follower to the speed of the driver is known as Train Value (TV).
6. 6. Simple Gear Train
7. 7. Idle gears / Intermediate gears Intermediate gears are called idle gears, as they effect the speed ratio or train value of the system. do not The idle gears serves the following two purposes; 1. T o connect gears at large centre distance. 2. T o obtain the desired direction of motion of the driven gear (i.e. clockwise or anticlockwise).
8. 8. Compound Gear Train When there are more than one gear on a shaft, as shown in Fig. is called as compound train of gear.
9. 9. Compound Gear Train • • Gear 1 is the driving gear mounted on shaft A Gears 2 and 3 are compound gears which are mounted on shaft B. Gears 4 and 5 are also compound gears which mounted on shaft C • are • Gear 6 is the driven gear mounted on shaft D. N1 = Speed of driving gear 1, T1 = Number of teeth on driving gear 1, N2 ,N3 ..., N6 = Speed of respective gears in r.p.m., T2 ,T3..., T6 = Number of teeth on respective gears.
10. 10. Compound Gear Train Since gear 1 is in mesh with gear 2, its speed ratio is; The speed ratio of compound gear train is obtained by multiplying the equations (i), (ii) and (iii),
11. 11. Compound Gear Train
12. 12. Numerical Example 1. The gearing of a machine tool is shown in Fig. The motor shaft is connected to gear A and rotates at 975 r.p.m. The gear wheels B, C, D and E are fixed to parallel shafts rotating together. The final gear F is fixed on the output shaft. What is the speed of gear F ? The number of teeth on each gear are as given below. Gear No. of teeth A 20 B 50 C 25 D 75 E 26 F 65
13. 13. Numerical Example 1. Solution