MASNUFACTURING PROCESSES – II（MASNUFACTURING流程二世）.pdf

Module 7 Screw threads and gear manufacturing methods Version 2 ME, IIT Kharagpur Lesson 32 Manufacturing of Gears. Version 2 ME, IIT Kharagpur Instructional objectives At the end of this lesson, the students will be able to (i) State the basic purposes of use of gears (ii) Cite the general applications of gears (iii) Classify the types of gears of common use (iv) Specify gears (v) Describe the different methods of manufacturing various types of gears (a) Preforming (b) Producing gear teeth by machining (c) Finishing gear teeth (i) Basic Purpose Of Use Of Gears Gears are widely used in various mechanisms and devices to transmit power and motion positively (without slip) between parallel, intersecting ( axis) or non-intersecting non parallel shafts, • without change in the direction of rotation • with change in the direction of rotation • without change of speed (of rotation) • with change in speed at any desired ratio Often some gearing system (rack – and – pinion) is also used to transform rotary motion into linear motion and vice-versa. Fig. 7.2.1 Features of spur gears and involute tooth profile Version 2 ME, IIT Kharagpur Gears are basically wheels having, on its periphery, equispaced teeth which are so designed that those wheels transmit, without slip, rotary motion smoothly and unifor