Determine the minimum tension that can exist in the belt without causing the belt to slip at pulley a. In this lab, you will make some basic measurements of friction. The coefficient of static friction between the belt and the pulleys is 0. Ppt belt friction powerpoint presentation free to view. In general dry friction describes the reaction between two solid bodies in contact with each other when they are in motion kinetic friction and when they are not static friction. Place the board to be measured on the conveyor belt and place the friction. First you will measure the coefficients of static friction between several combinations of surfaces using a heavy block and a set of hanging masses. When one end of the belt is being pulled only part of this force is transmitted to the other end wrapped about a surface. Introduction basically, belt friction is a term which use to describe the frictional forces between a belt and a surface, and in this experiment, it will be the frictional force with the surface of the pulley. Newtons laws, maximum static friction, kinetic friction, coecients of friction. Pdf mechanics and sliding friction in belt drives with.
The friction between the belt and pulley will decrease immensely if the belt happens to be muddy or wet, as it acts as lubricant to the force. A load is added to one of two hangers until the rope just begins to slide. Factors that affect belt friction include belt tension, contact angle, and the materials used to make the belt and pulleys. Lesson 66 friction, simple belt friction example jeff hanson. The transmission occurs through friction between the v belt and vertical spindle sheaves as a result of the relative slip motion 4,5. In this video i will derive the equation of the ratio of the tensions of a belt around a peg or drum with respect to friction and angle or number of times around the peg.
A pulle y reduces these effects with rolling contact between the cable and. The friction between the belt and wheel may be increased by the shape of the belt. A vee section or round section belt in a vee groove will grip better than a flat belt and is. The experiments also will determine the effect of the belt. Lawn tennis balls, rolling friction experiment and trouton.
Then, to determine the effect of the angle of warp to the power that can be transmitted for belt drive mechanism. Toothed belts do not rely on friction to transmit power, and they should not be confused with moldednotch v belts which transmit power by wedging action of the. A project report submitted in partial fulfilment of the requirement for the. During an experiment all were rotated together at a slow speed, about l rpm. Coefficient of friction between the belts and pulley. We are going to use the information that we learned about belts, in the last module and apply it to another static equilibrium problem. Lab 3 belt friction experiment belt mechanical friction. Friction, experiment and theory the lab this week investigates the frictional force and the physical interpretation of the coefficient of friction. Belts may be used as a source of motion, to transmit power efficiently, or to track relative movement. Lab 3 belt friction experiment free download as word doc. If a belt or cable runs around a fixed shaft, friction between the belt and the shaft can cause the efficiency to be low, and the cable can rapidly wear.
Vee belts also known as vbelt or wedge rope solved the slippage and alignment problem. The belt resembles a flat belt with evenly spaced teeth on the inside surface. This also applies to extremely dry or warm conditions which will evaporate any water naturally found in the belt, making friction much greater. This experiment is done to determine the coefficient of friction between belt and pulley. Using this free body digram we will rst sum the forces along both the y and xaxiss. Te is the sum of the tension required to move the empty belt tc, the tension. Belt friction full report belt mechanical friction scribd. Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience. We will make use of the concepts of the force of gravity, the normal force, the frictional force, tension, freebody diagrams, and objects sliding on an inclined plane. Mechanics and sliding friction in belt drives with pulley grooves article pdf available in journal of mechanical design 1282 march 2006 with 7,163 reads how we measure reads. Two types of belt used in this experiment is a flat belt and vshaped belt. Belt friction experiment free download as word doc. The objective of the experiments are to investigate the relationship between belt tensions, angle of wrap and coefficient of friction for flat and vbelts.
Factors studied in this experiment is the angle of contact between the belt and pulley. Pdf experimental investigation on the performance of a. The objective of the experiments are to investigate the relationship between belt tensions, angle of wrap and coefficient of friction for flat and v belts. The mechanics of friction in rope rescue stephen w. Belt friction in any system where a belt or a cable is wrapped around a pulley or some other cylindrical surface, we have the potential for friction between the belt or cable and the surface it is in contact with. What is the independent variable in this experiment. Belt tension calculator first, the effective belt tension te must be calculated. This is module 29 of applications in engineering mechanics. Pdf timing belt tooth goes into contact with a drive pulley, stretched to the maximum, because of the previous tension. Therefore, to properly define friction, we must first introduce the concepts of force and velocity. When one end of the belt is being pulled, only part of this force is transmitted to the other end. Also determine the corresponding resisting torque t. In any system where a belt or a cable is wrapped around a pulley or some other cylindrical surface, we have the potential for friction between the belt or cable and the surface it is in contact with. The coefficient of friction between the belt and the pulley depends upon following factors.
Results obtained from the belt friction experiment. The core of the unit is a cast iron pulley with grooves in its circumference for v belts and flat belts. The friction between the belt and the wheel is further affected by centrifugal force which tends to lift the belt off the wheel. The object of the experiments is to test flat belt with varying angles of lap around a pulley. The objective of the lab is to perform experiments which are related to mechanics of machine subject in order to understand the behavior of different mechanical. A v belt pulley as shown below is used to transmit a torque. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. Experimental investigation on the performance of a rope belt. F develop as a result of the applied incremental tensions. Belt friction experiment objective to determine the sliding coefficient of friction, between the belt and the pulley. The friction force increases with the amount of wrap about a. In this experiment we will classify the various forms of friction that are encountered in everyday life. Performance evaluation of friction belt apparatus using indigenous.
Lab 3 belt friction experiment belt mechanical friction scribd. Flat belt friction by justin cannon let us examine the picture taken from engineering mechanics by r. If the coefficient of static friction between the rope and the fixed circular drums a and b is 0. Four different pulleys are supplied with different vee groove angles. Fabricating a conveyor belt setup we have measured rolling friction coe. This work experiment was carried out in the mechanics. Friction, experiment and theory mcmurry university. The coefficient of friction is much higher for the worn belt. Abstract a new insight into the mechanics of belt friction is given. Because of its wide importance, the mechanics of belt friction and eulers formula1 relating the pullforce to the hold force applied at two ends of the belt are discussed in every undergraduate textbook of engineering mechanics. Both static and kinetic friction are proportional to the normal force exerted between the two solid bodies. The factors to be discussed is the use of belt and the angle of contact between belt and pulley. Just as a note these are parallel and perpendicular to the normal force and we will be assuming that there. Tm 220 belt friction apparatus friction of v belts and flat belts on metal pulleys technical description this experimental unit enables experiments to be performed on belt drives and belt friction.
Then the empirical data may be compared with the theoretically derived solutions and the coefficients of friction evaluated for all the belts types. The laboratory has performed its duty, which is to measure and report the shear strength under speci. Figure 1 shows the force of friction between two surfaces. Belt friction is a term describing the friction forces between a belt and a surface, such as a belt wrapped around a bollard. The friction force makes tension in the belt be different at both ends.
Determine belt friction using belt friction apparatus. So, the friction in this situation between the belt and the drum is going to resisted that impending motion, and we see that we have got an angle of surface contact which we are going to call belta over which the cable or belt or rope contacts the drum. The flat belt then overcomes the resisting torque t at pulley b and rotates the pulley b clockwise. Download as docx, pdf, txt or read online from scribd. Then the empirical data may be compared with the theoretically derived solutions and the coefficients of friction evaluated for all the belts.
Belt theory friction drives v belts and vribbed belts the figure to the left illustrates the basic idea of static friction. There are two types of belt, which are flat belt and vbelt. Measure 40cm of length on the lab table surface with the meter stick and mark the start and finish. Experimental investigation on friction and wear behavior. The tm 220 experimental unit allows the study by experiment of belt drives and belt friction. Belt friction is for experiment that use in the lab and the report is ready for all. Lab 3 friction belt experiment free download as pdf file. The coefficient of friction is the lowest was for the round belt.
Theory friction is the force that resists the relative. Belt and wrap friction when flat belts, v belts, band brakes, and linewrap around capstans are used in any form of product, the frictional forces developed must be determined. Belt drives depend on friction to operate, but excessive friction wastes energy and rapidly wears the belt. Force what is commonly referred to as friction is actually a frictional force. At the core of the experimental unit is a cast iron pulley, whose circumference features grooves for v belts and flat belts. The mechanics of belt friction revisited uc san diego. The vertical spindle sheaves and v belt contact will create a sliding friction between two surfaces, and this leads to the presence of abrasive wear.
Belt friction band brakes torque transmission capstan use less smaller force to hold loads pulley raising or lowering loads theory relate t1 and t2 when belt is about to slide to right. A conceptual and methodological drawback in the presentation of the classical derivation of the force required to pull the belt over a. They require tension to maintain the right amount of friction. Flat belts are the purest form of friction drive while v belts have a friction multiplying effect because of wedging action on the pulley. Molded belt teeth are designed to make positive engagement with mating grooves on a pulley or sprocket. Friction drive belts rely on the friction between the belt and pulley to transmit power.
Coefficient of friction between the belts and pulley depends upon various factors like material of belt, material of pulley, belt speed and slip of belt. Friction force helps control the lowering of rescuers, however, friction force fights against the rescuer during a raise. The apparatus consists of a wall mounted fixed pulley with a loaded belt. The ropebelt friction apparatus borders on belt friction which describes the friction forces between a. Touching the flat belt with a pulley is as shown below.