Common belt types shigleys mechanical engineering design type pulley 1. Dp n august 15, 2007 11 a flatbelt system has small pulley with 6inch diameter and large pulley with 10inch diameter. Floors should be clean and free of oil and debris to insure good footing and balance while working on machinery. The mechanical belt drive, using a pulley machine, was first mentioned in the text the dictionary of local expressions by the han dynasty philosopher, poet, and politician yang xiong 5318 bc in 15 bc, used for a quilling machine that wound silk fibers on to bobbins for weavers shuttles.
Mechanisms drives electromechanical technology series. In general, the drives are in the integralhorsepower class as distiguished from light duty of fractional horsepower drives. Prying a belt damages cables in the belt, leading to early belt failure. The belt rq because of more tension is known as tight side, whereas the belt lm because of less tension is known as slack side, as shown in fig. Belt conveyors for bulk materials fifth edition chapter 6.
Applications belt driven ocean racing yachtwhen a mechanical gearbox system wouldnt work to drive the canting keel on the ocean racer maximus, designers turned to a gates poly chain gt2 belt drive to get the job done. Md14 belt and chain drives university of northern iowa. Problem 1 based on belt drive power transmission theory of machine duration. Maiti, department of mechanical engineering, iit kharagpur. Toothbelt drives preload in a toothedbelt system is required in order to keep the teeth from attempting to climb up the sides of the grooves in the sprockets, and, in extreme cases, from jumping ratcheting under the most severe loading conditions. This manual covers three v belt cross sections and pulley groove sizes designated 3v, 5v and 8v. The circular belt or rope is circular in section as shown in figure 8.
For a given weight on the belt, the torque to turn the belt is always the same regardless of speed. Special attention has been given to electrical vsds and especially to ac drives. Pdf mechanics and sliding friction in belt drives with. In that work special attention is directed to the motion of the belt. For getting the optimal performance and the desired results from the belt drive the selection of the right belt according to the application becomes crucial. The super ii vbelt was designed specifically for severe drives, and tests show that it lasts far longer than conventional vbelts in these types of applications. In general, the drives are in the integralhorsepower class as distinguished from light duty or fractional horsepower drives. A modern development seen on some cars, is a flat belt with a series of mini vees on the inner surface.
Determine allowable forces and torques for flexibledrive systems, along with the necessary sprockets or sheaves. Material imperfections lead to a service life distribution. But vbelt drive systems, also called friction drives because power is. A belt drive is designed based on the design power, which is the modified required power. In a two pulley system, depending upon the direction the belt drives the pulley, the belt drives are divided into two types. Most belt drives consist of flat leather, rubber, or fabric belts running on cylindrical pulleys or of belts with a vshaped cross section running on grooved pulleys. A ratio is a proportional factor between two similar objects of different sizes. It will be clear already from the foregoing brief and incomplete account that creep theory cannot be expected to explain the behaviour of the inextensible type of belt described in the introduction, and that the new circumstances require a fresh examination of the principles involved. One or more vbelts may be used on a drive, as required, to transmit the horsepower load. Car shredder when a vehicle is shredded, the load on the 6,000hp motor fluctuates rapidly.
Wearing gloves, work around the belts, checking for cracks, frayed spots, cuts, or unusual wear patterns. Thread sprocket onto carrier body until sprocket stops and locks against the washer and carrier body flange fully seating nylatron washer into recess of sprocket. Cross sections of vbelt scope this manual covers vbelt drives used primarily for power transmission in industrial applications. These are more suitable for power transmission between two shafts having a short centre distance. Service factors for different kinds of driven machines combined with different types of driving units are shown in table. There are flat belt and v belt used for the power transmission. The amount of power transmitted depends upon the following factors. Lecture series on design of machine elements i by prof.
Identify correctly five types of belt drives and give an appropriate application of each. Power transmission devices mechanical engineering mcq. Cs34a compensator installation instructions belt drives. Belt belts are looped over pulleys belt drive when a belt is used for power transmission it is called a belt drive. Every belt drive must be guarded when in operation. The speed ratio would be stable if slippage did not occur. If the block weighs w perpendicular to the surface and the force parallel to the surface f can be applied to the side of the block before it begins moving, then the coefficient of static friction. Vbelt selection its a veritable cinch machine design. Several ropes also can be used together to transmit more power. Keep area around drives free of clutter, debris and other obstructions. Mechanismsdrives is an introductory treatment of modern mechanical drives, combining the elements of mechanical theory with those of practicality. Tolerances on belts and pulleys lead to a nonuniform tension distribution among the belts in a multiple belt drive. Vbelts can transmit more power as compared to flat belts due to wedging action in the grooves.
Belt and chain drives august 15, 2007 2 august 15, 2007 3 objectives understand principles of operation of flexibledrive systems. Belt number factor in multiple vbelt drives journal of. The belts or ropes are used to transmit power from one shaft to another by means of pulleys which rotate at the same speed or at different speeds. The selection of a v belt drive for any application should be based on the nature of the load and the type of driving unit. The service factor depends on hours of running, type of shock load expected and nature of duty. The driver pulley pulls the belt from one side and delivers it to the other side. Page 1 module belt drives version 2 me, iit kharagpur page 2 module belt drives version 2 me, iit kharagpur lesson 3 design of v belt drives version 2 me, iit kharagpur page 3 module belt drives version 2 me, iit kharagpur lesson 3 design of v belt drives version 2 me, iit kharagpur instructional objectives. Belt drives have low power transmitting capacity 4. The belt transmits power by friction contact between the belt and the driving and driven sheave.
Belt drives driving force, fd ff fb torque, t ff fb r fd r ratio of belt drive is similar to gears surface velocity, vmm ftmin 1 2 w d d m 12. In the paper during the analysis is used timing belt with belt pulley, which is the part of the device for testing of mechanical properties of timing belt drives 456789 10 1112. Belt drives industrial wiki odesie by tech transfer. Today the majority of belts in use are of vee cross section, often used in sets of three side by side. Stress variation in the cord of the belt is treated in another report 3. Belt tension, power, and drive engineering 90 k x idler friction factor the frictional resistance of idler rolls to rotation and sliding resistance between the belt and the idler rolls can be calculated by using the multiplying factor k x. Idler pulley is a pulley which does not transmit power but assist power transmission by increasing angle of. What is belt drive and what are its types engineering. A selection of arrangements of belt drives is shown in the diagram below. In a belt drive system, a ratio is used to determine the speed relation between two vbelt pulleys. Belt drive, in machinery, a pair of pulleys attached to usually parallel shafts and connected by an encircling flexible belt band that can serve to transmit and modify rotary motion from one shaft to the other. K x is a force in lbsft of conveyor length to rotate the idler rolls, carrying and return, and to.
The most common systems for transmitting power from a drive to a driven shaft are belt, gear, and chain drives. Belt life varies greatly depending on not only how the belt is installed, but on how the belt is tensioned at installation. Mark or note a point on the belt, or on one of the belts in a multiple vbelt drive. In a previous report 2 the author presents a new theory for vbelt drives. Open belt drive open belt drive is used when sense of rotation of both the pulleys is same. Twenty three short answer questions on power transmission question. Belt theory friction drives vbelts and vribbed belts the figure to the left illustrates the basic idea of static friction. Belt drives are used as the source of motion to transfer to efficiently transmit power or to track relative movement. Design of v belt drives module belt drives lesson 3. Belt drives a belt is a looped strip of flexible material, used to mechanically link two or more rotating shafts.
Belt drives with pulley grooves the steady mechanics of a twopulley belt drive system are examined wher e the pulley gr ooves, belt extension and wedging in. Variable frequency drives vfds popular speed control devices used in industrial, commercial and residential applications. Both phenomena contributes to the life of the drive i. In a static nonmoving toothedbelt drive, the tension force in each span of the belt is. Conti professional simplifies design of belt drives. Introduction the belts are used to transmit power from one shaft to another by means of pulleys which rotate at the same speed or at different speeds. The modification factor is called the service factor. When the exact weight of the belt is not known, use average estimated belt weight see table 61 w m weight of material, lbs per foot of belt length. When a belt is loose it will slip, causing excess heat. Selection of the right kind of belt for a given application will depend upon the type of drive used, operating rpm, horsepower generation, diameter of pulleys and center distance, take up design, space available for the. Belt drive is used in applications having constant speed drive 2. Conti professional simplifies design of belt drives hannover messe 2018 in conti professional, continental offers a design program for two and multipulley drives. The webbased application can be run in a browser to calculate drives using openended or endless belts, with the number of pulleys userdefinable between two and 20.
Belt drives for power transmission are classed as frictional drives. Unit 3 power transmission devices devices structure 3. Pulleys transmit power from one location to another, and they can form a transmission ratio. The driven machines are representative examples only.
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