Module 2 GEARS Lecture 1 INTRODUCTION （模块1 2 齿轮讲座介绍）.pdf

Machine Design II Prof. K.Gopinath Prof. M.M.Mayuram Module 2 - GEARS Lecture 1 - INTRODUCTION Contents 1.1 History of gears 1.2 Definition of gears 1.3 Types of gears and their applications. 1.4 Spur Gear 1.5 Helical Gear 1.6 Double helical or Herringbone Gear 1.7 Internal Gear 1.8 Rack and pinion 1.9 Bevel Gear (a) Straight (b) Spiral (c) hypoid 1.10 Crossed helical gear 1.11 Law of gearing 1.12 Gear profiles 1.13 Meshing of gears 1.1 HISTORY OF GEARS Indian history as per our mythological stories is more than 12,000 years old. Since then people living here have been striving to improve the living conditions. We also know that earlier people were living in the caves and the doors of the caves were made of granite. How were these heavy doors opened and closed? They were opened and closed by none other than a system with gear mechanism, wheel, lever and rope drives. However, the documented evidence has been lost due to destruction by the invaders and improper storing of palm leaf literature. The guru Kula method of teaching and passing of the information from mouth to ear procedure and keeping some of the advances as clos