tailieunhanh - Ebook A textbook of theory of machines: Part 2

(BQ) Part 1 book "A textbook of theory of machines" has contents: Gear trains, gyroscopic couple and precessional motion, inertia forces in reciprocating parts, steam engine valves and reversing gears, governors, brakes and dynamometers, balancing of rotating masse, balancing of reciprocating masses, balancing of reciprocating masses,. and other contents. | CONTENTS CONTENTS 428 l Theory of Machines 13 eatur tures Features 1. Introduction. Gear Trains 2. Types of Gear Trains. 3. Simple Gear Train. 4. Compound Gear Train. 5. Design of Spur Gears. 6. Reverted Gear Train. 7. Epicyclic Gear Train. 8. Velocity Ratio of Epicyclic Gear Train. 9. Compound Epicyclic Gear Train (Sun and Planet Wheel). Introduction . Introduction Sometimes, two or more gears are made to mesh with each other to transmit power from one shaft to another. Such a combination is called gear train or train of toothed wheels. The nature of the train used depends upon the velocity ratio required and the relative position of the axes of shafts. A gear train may consist of spur, bevel or spiral gears. . Types of Gear Trains 10. Epicyclic Gear Train With Bevel Gears. Following are the different types of gear trains, depending upon the arrangement of wheels : 11. Torques in Epicyclic Gear Trains. 1. Simple gear train, 2. Compound gear train, 3. Reverted gear train, and 4. Epicyclic gear train. In the first three types of gear trains, the axes of the shafts over which the gears are mounted are fixed relative to each other. But in case of epicyclic gear trains, the axes of the shafts on which the gears are mounted may move relative to a fixed axis. . 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. When the distance between the two shafts is small, the two gears 1 and 2 are made to mesh with each other to 428 CONTENTS CONTENTS Chapter 13 : Gear Trains l 429 transmit motion from one shaft to the other, as shown in Fig. (a). 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. It may be noted that the motion of the driven gear is opposite to the motion of driving gear. (a) (b) (c) Fig. . Simple gear train. Let N 1 = Speed of gear .