This chapter will explore the theory of gear tooth action and the design. The velocity ratio of an epicyclic gear train is determined by the following methods. Understand gear trains and how to calculate ratios. Theory of machines is an applied science of the relationships between geometry and relative motion of the parts of the machine, and concerns to the forces which. In this lecture, i shall give a brief history of toothed gear invention and development and next something about the gear train, then special sophisticated gearing. N is the gears teeth number, the sign depends on the type of gear and, in sequence is for external gears. In some epicyclic gear trains, we may find two or more planetary gears. Study and analyze the gear profiles and gear trains. This video is part of the content developed by nptel, a joint initiative of all iits and iisc. Image from blog of haja sherief image from hpi racing image from proquest image from sandia national labs image from piaget image from fortune, apr. Enable power transmission at varied angles and varied lengths. Unit 7 gear trains, kinematics of machines of vtu syllabus prepared by hareesha n gowda, asst. Compound planetary gear train planetary gear train with more than one arm r14 t1t3. Depending upon the type and accuracy of motion desired.
If the mating gear has more teeth than the pinion, that is. Nptel syllabus kinematics of machines video course s note on the model curriculum prepared by aicte five of the seven topics listed under the heading kinematics of machine belongs to dynamics. Recognize different gearing systems and relative advantages and disadvantages between. Geartrain calculates the angular velocity of the final driven gear in a gear chain. Gear design national broach and machine division,of lear siegler, inc. The user enters the revolutions per minute and driection of the first driver gear along with information about. Gear trains simple, compound and epicyclic gear trains. Gear trains image from simon fraser university image from jtekt torsen na, inc. Whenever a change in the speed or torque of a rotating device is needed, a gear train or one of its cousins, the belt or chain drive mechanism, will usually be used. The number of teeth for spur gears is given by where k 1f fll1 for fulld tht th08f tbt th d ldepth teeth, 0. It is a mathematical equation that tells how many values can vary and can help in the first three types of gear trains, the axes of the shafts over which the gears are mounted are ger relative to. Provide a varied leverage between the engine and the drive wheels provide means to transfer power in opposite direction. A gear can be defined as a toothed wheel which, when meshed with another toothed wheel with similar configuration, will transmit rotation from one shaft to another.
Provide means of connection and disconnection of engine with rest of power train without shock and smoothly. Gear trains are widely used in all kinds of mechanisms and machines, from can openers to aircraft carriers. Asok kumar mallik department of mechanical engineering iit kanpur. Complex numbers, belt drive, gears, gear trains and mass balancing. Design of machinery an introduction to the synthesis and. The smallest number of teeth on a spur pinion and gear, onetoone gear ratio, which can exist without interference is np.
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