Basic mechanical-engineering
- 1. BASIC MECHANICAL ENGINEERING Unit –I: Introduction to Mechanical Engineering (Shaft & Keys)
- 2. Introduction to Machine: Device consisting of various elements to perform the prescribed task to satisfy the human needs E.g. Pump Set, IC Engine, Turbine etc. INPUT (Source of Energy) Machine (Arrangements of Elements) Output (Prescribed Task)
- 3. Classification of Machine Elements:
- 4. Shafts: A shaft is a rotating member, circular cross-section, solid or hollow, to transmit power or motion To transmit the power using shaft different members are used such as, Gears, Pulleys, Sprockets Types: A) Transmission Shaft B) Machine Shafts
- 5. A) Transmission Shafts: Transmit the power from source to the machine absorbing the power Mountings: Gears, Pulleys etc. Subjected to torque, BM and axial force Types: Line Shaft and Counter Shaft
- 6. Difference between Line shaft & Counter Shaft: Sr. No. Line Shaft Counter Shaft 1. Directly driven by prime mover and using this power is supplied to diff. machines Secondary shaft driven by main shaft using belt, chain or gear 2. Directly connected to PRIME MOVER NOT DIRECTLY CONNECTED
- 7. Difference between Line shaft & Counter Shaft: Sr. No. Line Shaft Counter Shaft 3. Example Example
- 8. Properties of Shaft PROPERTIES: 1. High Static Strength 2. High Fatigue Strength 3. Ductility 4. High Resilience 5. Good Machinability
- 9. Material: ▪Ductile material like PLAIN CARBON STEELS AND ALLOY STEELS. ▪BRITTLE Material like CAST IRON can not be used Material for Shaft
- 10. ▪Material for key is Plain Carbon Steel or Alloy Steels. ▪Its having lower strength than Shaft material to ensure that if at all there is failure the key should fail instead of shaft. Keys:
- 11. Types of Keys: Sr. No. Type Feature Application 1 Sunk Keys Provided half in the keyway of shaft and half in the keyway of hub Mountings of flanges, pulleys, gears etc a. Rectangular Key Rectangular tapered cross section b. Square key Square tapered cross section c. Parallel key Rectangular or square without taper Used in gear boxes where axial movement is restricted d. Gib-headed key Rectangular key with head at one end for easy removal of key Used in mountings of pulleys, gears, inaccessible key seats e. Feather key Special type parallel key attached to either shaft or hub to prevent the relative rotary motion but, permits relative axial movement Clutches and gear shifting devices f. Woodruff key It’s a segment from cylindrical disc Machine tools and automobiles
- 12. Types of sunk keys:
- 13. Types of keys: Sr. No. Type Feature Application 2 Saddle Keys Tapered key fits completely only in hub of rotating element Light duty applications, used temporarily fastening in fixing and eccentric cams 3 Tangent keys Two tapered rectangular keys placed 90⁰ apart Heavy duty industrial applications 4 Kennedy keys Two tapered square keys placed 90⁰ apart Heavy duty industrial applications 5 Round keys and taper pins Straight pin of circular cross section Low power drives 6 Splines Multiple keys which are made integral with shaft Automobile gear box and machine tool gear boxes
- 15. References ▪Machine Design Book by J.K. Gupta and R.S. Khurmi ▪Design of Machine Elements Book by V. B. Bhandari ▪Basic Mechanical Engineering book by R. B. Patil and Singhal