570 | Page BENDING STRESS ANALYSIS OF SPUR GEAR BY USING MODIFIED LEWIS FORMULA 1 Namrata S.Gadakh, 2 Prof. R.S. Shelke 1 P.G. Scholar Mechanical SVIT Nashik Pune University 2 Assistant Professor (Mechanical Dept.) SVIT Nashik, MS (India) ABSTRACT Gears are one of the most important component in mechanical power transmission systems. The bending stress of the gear tooth is regarded as one of the key contributors for the failure of the gear in the gear set. Thus, analysis of stresses has become popular as an area of study on gears to minimize the chances of failures and also for the optimal design of gears. The analytical study is based on Modified Lewis formula. The project is basically concerned with ANALYSIS of SPUR gears which are actually used in all types of two wheelers. For doing analysis I taken the SPLENDOR of HERO HONDA company. I can determined stress in tooth of spur gear by using Modified Lewis equation. Keyword: Bending stress, Spur gear, Modified Lewis theory I. INTRODUCTION Gears are used for a variety of applications. They have numerous applications starting from textile looms to aviation industries. They are the most frequent ways of transmitting power. They will change the rate of rotation of machinery shaft as well as the axis of rotation. For high speed machine, such as an motor vehicle transmission, they are the optimum medium for low energy loss, high accuracy and reliability. Their function is to convert input provided simply by prime mover into an output with lower velocity and corresponding higher speed. Toothed gears are being used to transmit the power with high velocity ratio. In this phase, they face large stress at the point of contact. A set of teeth for is generally subjected to two types of cyclic stresses: i) Bending stresses inducing bending fatigue ii) Contact stress causing contact fatigue. Both equally these kind of stresses may well not achieve their maximum values at the exact same point of contact. Nevertheless, combined action of that they are all is the reason of failure of gear tooth leading to fracture at the bottom layer of a tooth underneath bending fatigue and surface area failure, due to call fatigue. When loads will be applied to the body, their surfaces deform elastically near to the point of speak to. Stresses developed by Normal force in a photo-elastic type of gear teeth are displayed in the Fig.1.1. The highest stresses can be found at the region where the lines are bunched nearest together. The greatest stress arises at two locations: A. At contact point exactly where the force F work. B. At the fillet region near to the base in the tooth. [1]