tailieunhanh - Text Book of Machine Design P13

CONTENTS CONTENTS 470 C H A P T E R n A Textbook of Machine Design 13 1. 2. 3. 4. 5. 6. 7. 8. Introduction. Types of Keys. Sunk Keys. Saddle Keys. Tangent Keys. Round Keys. Splines. Forces acting on a Sunk Key. Strength of a Sunk Key. Effect of Keyways. Shaft Couplings. Requirements of a Good Shaft Coupling. Types of Shaft Couplings. Sleeve or Muff Coupling. Clamp or Compression Coupling. Flange Coupling. Design of Flange Coupling. Flexible Coupling. Bushed Pin Flexible Coupling. Oldham Coupling. Universal Coupling. Keys and Coupling 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. Introduction A key is a. | CONTENTS C H A P T E R 13 Keys and Coupling 1. Introduction. 2. Types of Keys. 3. Sunk Keys. 4. Saddle Keys. 5. Tangent Keys. 6. Round Keys. 7. Splines. 8. Forces acting on a Sunk Key. 9. Strength of a Sunk Key. 10. Effect of Keyways. 11. Shaft Couplings. 12. Requirements of a Good Shaft Coupling. 13. Types of Shaft Couplings. 14. Sleeve or Muff Coupling. 15. Clamp or Compression Coupling. 16. Flange Coupling. 17. Design of Flange Coupling. 18. Flexible Coupling. 19. Bushed Pin Flexible Coupling. 20. Oldham Coupling. 21. Universal Coupling. Introduction A key is a piece of mild steel inserted between the shaft and hub or boss of the pulley to connect these together in order to prevent relative motion between them. It is always inserted parallel to the axis of the shaft. Keys are used as temporary fastenings and are subjected to considerable crushing and shearing stresses. A keyway is a slot or recess in a shaft and hub of the pulley to accommodate a key. Types of Keys The following types of keys are important from the subject point of view 1. Sunk keys 2. Saddle keys 3. Tangent keys 4. Round keys and 5. Splines. We shall now discuss the above types of keys in detail in the following pages. 470 CONTENTS Keys and Coupling 471 Sunk Keys The sunk keys are provided half in the keyway of the shaft and half in the keyway of the hub or boss of the pulley. The sunk keys are of the following types 1. Rectangular sunk key. A rectangular sunk key is shown in Fig. . The usual proportions of this key are Width of key w d 4 and thickness of key t 2w 3 d 6 where d Diameter of the shaft or diameter of the hole in the hub. The key has taper 1 in 100 on the top side only. Fig. . Rectangular sunk key. 2. Square sunk key. The only difference between a rectangular sunk key and a square sunk key is that its width and thickness are equal . w t d 4 3. Parallel sunk key. The parallel sunk keys may be of rectangular or square section uniform in width and thickness .