A large gear pump to move transmission fluid around. Epicyclic gear train in combing machine motion of detaching roller, combing cycle index, web movement in one cycle of combing. Gear design and strength iupital has good strength, durability, wear resistance, and chemical resistance, so can be used to each gear. Ordinary gear trains have axes, relative to the frame, for all gears comprising the train. Jan 24, 2008 39 videos play all mechanical kinematics of machines nptelhrd types of gear trains basic, formula and numerical problems approach for gate duration.
Nptel syllabus mechanics of textile machinery web course course outline machine elements and drives introduction to drives, selection of drives, primary machine. Straight bevel gearing is similar to spur gearing with perpendicular shaft arrangement. Oct 07, 2015 gear ratio is numbers of teeth of larger gear to smaller gear. One is that the bushing needs to be wider to t over the cap on the pinion. Types of gear train and velocity ratio calculation techminy. Design of machinery an introduction to the synthesis and. Software gto provides the required results in a very short time.
Asok kumar mallik department of mechanical engineering iit kanpur. 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. Stadtfeld introduction the most basic case of a gear train is the transmission of rotation and power between two parallel shafts. Comparison of gear efficiencies spur, helical, bevel, worm. It require small area during the power transmission and to obtain large speed reduction. If the driver rotates at 400 rpm, the idler rotates at 300 rpm, and the driven gear also rotates at 300 rpm. If the transmission of rotation should occur with a constant ratio, which means that in case of a con. 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. If the mating gear has more teeth than the pinion, that is. March 29, 2020 admin medical leave a comment on gear trains nptel pdf.
In absence of lubricant additives and antifriction coating, gears will be subjected to direct friction. An example is a gear box that modifies the torque speed characteristic of a prime mover to match that of the load, and comprises gears, shafts, bearings, and seals. The variable gear train is often coupled with a clutch. The advantage of a compound gear train over a simple gear train is that a much larger speed reduction from the first shaft to the last shaft can be obtained with small gears. Usually, following two types of lubrication mechanisms are commonly used for gear lubrication. 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. Kinematics of gear trains conventional gear trains. Mar 29, 2020 smaller gear is known as pinion and larger mating gear is called gear. Gear train conguration appendix a8 another interesting design aspect is that the gear train reverts back to the axle about which the pinion turns.
Higher value of t f cause scuffing failure of gears. Detailed course content with modules for video lectures module 1 3 hr. Apr 25, 2020 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. Lecture gear unit design failure of gear tooth probable dynamic load and wear load. Gear surfaces coated with boundary additive or antifriction. Gear trains image from simon fraser university image from jtekt torsen na, inc. Epicyclic gear trains in roving machine bobbin diameter and speeds of bobbin, roving stretch, relation between bobbin speed and bottom cone pulley speed, epicyclic gear train in combing machine motion of detaching roller, combing cycle index, web movement. In absence of lubricant additives and antifriction. Following are the different types of gear trains, depending upon the arrangement of wheels.
Gear trains are widely used in all kinds of mechanisms and machines, from can openers to aircraft carriers. Spur gear helical gear double helical or herringbone gear internal gear rack and pinion bevel gear a straight b spiral c hypoid 1. This is a twodimensional case which allows for observation in a plane. Reverted gear train when the axes of the first gear i. The smallest number of teeth on a spur pinion and gear, onetoone gear ratio, which can exist without interference is np. Jan 01, 20 kinematics of gear trains conventional gear trains. Circumferential velocities in a complex gear train have 3. This study shows examples of reliability figures for gearboxes under given conditions and provides an insight into how specific gearboxes in. An incredibly odd hydraulic system that controls the clutches and bands. Introduction to gear trainsintroduction to gear trains.
Provide a varied leverage between the engine and the drive wheels provide means to transfer power in opposite direction. When two teeth on a helical gear system engage, the contact starts at one end of the tooth and gradually. Enable speed reduction between engine and the drive wheels in. The volume of the gear train with spur gears is reduced by 22. Spur gear design and selection objectives apply principles learned in chapter 11 to actual design and selection of spur gear systems. The gear 3 which is now the second driver drives the gear 4 i. 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. With increase in pitch line velocity, lubricant used should be less viscous in order to min. Gears and gear trains study notes for mechanical engineering.
Its efficiency varies from 94% to 98% with lower gear ratios. Smaller gear is known as pinion and larger mating gear is called gear. In some epicyclic gear trains, we may find two or more. Calculate forces on teeth of spur gears, including impact forces associated with velocity and clearances. Gears is a positive drive which transmits exact velocity ratio from one shaft to another shaft, gear drive is used when the distance between driver and follower is very less, when two or more gears are made to mesh with each other to transmit power from one shaft to another, the combination is called gear trains. A gear train is a set or system of gears arranged to transfer rotational torque from one part of a mechanical system to another, with some gear ratio performing a mechanical advantage. Epicyclic gear trains are generally used for automatic transmission, overdrives, and final drives.
A gear whose axis itself is revolving is called a planetary gear. The gear train maybe for spur gear, helical gear and spiral gear. The number of teeth for spur gears is given by where k 1f fll1 for fulld tht th08f tbt th d ldepth teeth, 0. Oct 23, 2012 spur gearing is a parallel shaft arrangement, and these gears can achieve much higher efficiencies compared to other gear types. Often gears are treated as pitch cylinder, which roll together without slip as shown in fig. Jan 24, 2008 lecture series on kinematics of machines by prof. Provide means of connection and disconnection of engine with rest of power train without shock and smoothly. That is a facto for the studied planetary gearboxes. The total mechanical loss is then given as the sum of losses from all gear meshes and bearings. When pinion is the driver, it results in step down drive in which nptl output speed. It require small area during the power transmission and to obtain large. Input parameters teeth type common or spiral gear ratio and tooth numbers pressure angle the angle of tool profile. Figure 76a shows a simple ordinary train in which there is only one gear for each axis.
Enable power transmission at varied angles and varied lengths. These types of gear trains are used widely in automobile manual transmission systems. Mechanical vibrations nptel online videos, courses iit. Pressure line is the common normal at the point of contact of mating gears along which the driving tooth exerts force on the driven tooth. This chapter will explore the theory of gear tooth action and.
Epicyclic gear train nptel pdf merge friction losses can be divided into two major categories. Apr 04, 20 reverted gear train when the axes of the first gear i. Gear wreck will happen because of its tooth fatigue and tooth surface wear, so strength design from both side is necessary. Epicyclic gear train nptel pdf automatic transmission has not better fuel economy.
Jul 03, 2019 epicyclic gear train nptel pdf to excel pdf files kinematic analysis of synchromesh, machine tool gear box, differential gear box self study 3. 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. Another class of gear train has wide application, the epicyclic or planetary train. Mar 29, 2020 epicyclic gear train nptel pdf merge sijthre. It is composed of clutch the gear box propeller shaft universal joints rear axle wheel tyres. In the first three types of gear trains, the axes of the shafts over which the gears are mounted are fixed relative to each other.
The first gear known as the driver has 12 teeth, the second gear called the idler has 16 teeth, and the third gear known as the driven also has 16 teeth. In figure 76b a compound ordinary train is seen to be one in which two or more gears may rotate about a single axis. Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, or sun gear. Nptel textile engineering mechanics of textile machinery. A gear train is usually made up of two or more gears. Determine allowable force on gear teeth, including the factors necessary due to. 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. The teeth on helical gears are cut at an angle to the face of the gear. Variable gear train is a compound gear train, which has a variable gear reduction ratio. Pressure angle is the angle between the pressure line and common tangent to pitch circles. The gear wheel transmitted motion between one shaft to another shaft, so the multiple set of gear transmit motion from single main gear to various revolving parts is known as gear train. Epicyclic gear train nptel pdf in the first three types of gear trains, the axes of the shafts over which the gears are mounted are.
Gear life depends on effective lubrication, which can be quatified by minimum film trajns to r compositeas shown in fig. Gears is a positive drive which transmits exact velocity ratio from one shaft to another shaft, gear drive is used when the distance between driver and follower is very less, when two or more gears are made to mesh. Nptel video lectures, iit video lectures online, nptel youtube lectures, free video lectures, nptel online courses, youtube iit videos nptel courses. Yi zhang with susan finger stephannie behrens table of contents. For the gear train shown below, determine the train value, output speed, output direction, output torque, and output power.
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