When pinion is the driver, it results in step down drive in which nptl output speed. Gear life depends on effective lubrication, which can be quatified by minimum film trajns to r compositeas shown in fig. Epicyclic gear trains are generally used for automatic transmission, overdrives, and final drives. Helical gearing, in which the teeth are cut at an angle with the axis of rotation, was developed after spur gearing and has the advantages that has the smoother action and tends to be trainw fig. Epicyclic gear train nptel pdf merge the total mechanical loss is then given as the sum of losses from all gear meshes and bearings. Gear train it is defined as two or more gears are made to mesh with each epicyclic gear train the axes of the shafts over which the gears are mounted, may move relative to a fixed axis.
With increase in pitch line velocity, lubricant used should be less viscous in order to min. Nptel textile engineering mechanics of textile machinery. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy. In some epicyclic gear trains, we may find two or more. Textile engineering mechanics of textile machinery nptel. March 29, 2020 admin medical leave a comment on gear trains nptel pdf. In some epicyclic gear trains, we may find two or more planetary gears. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. Gear surfaces coated with boundary additive or antifriction. In absence of lubricant additives and antifriction.
Gear train it is defined as two or more gears are made to mesh with each epicyclic gear train the axes of the shafts over which the geaar are mounted, may move relative to a fixed axis. Epicyclic gear train nptel pdf merge friction losses can be divided into two major categories. Smaller gear is known as pinion and larger mating gear is called gear. Introduction to gear trainsintroduction to gear trains. Often gears are treated as pitch cylinder, which roll together without slip as shown in fig. A gear a mounted on shaft x having 50 teeth drives the gear b having 75 teeth mounted. In absence of lubricant additives and antifriction coating, gears will be subjected to direct friction. Epicyclic gear train nptel pdf merge this planetary gear train consists of a sun gear yellow, planet gears blue supported by the. A gear whose axis itself is revolving is called a planetary gear. Asok kumar mallik department of mechanical engineering iit kanpur. Detailed course content with modules for video lectures module 1 3 hr. Gear trains train of gears widely used on machines to transfer motion from one element to many elements. Yi zhang with susan finger stephannie behrens table of contents. Kinematics of gears and gear trains it is decided that the topics on dynamics listed above i to v will be covered in the course on dynamics of machines whereas the topic a above will be covered in kinematics of machines course.
The total mechanical loss is then given as the sum of losses from all gear meshes and bearings. In some cases, such as the automotive differential, one input is provided the. Another class of gear train has wide application, the epicyclic or planetary train. Higher value of t f cause scuffing failure of gears. A compound gear train with gears p, q, r and s has number of teeth 25, 51, 17 and 25 respectively.
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