(Be sure to use the full, circular belt length - not just the length of the stroke.)Īlso, remember that the applied load is typically mounted to the belt via a carriage or table, so the mass of this part should be included in the mass of the applied load. R = radius of driven pulley (m) The belt and the load can be considered a point mass that rotates around the driven pulley.īelt manufacturers typically provide mass (or weight) information per unit length, so the mass of the belt can be found by multiplying the mass per unit length by the total length of the belt. J L = inertia of belt and applied load (kgm 2) The applied load and the belt can be modeled as a point mass that rotates around the driven pulley, and their inertia can be calculated as: Since inertia depends upon the axis around which the component rotates, we can start by considering the applied load and the belt together, since they both rotate around the axis of the driven pulley. The inertia of each component can typically be estimated with sufficient accuracy by using the standard inertia equations for simple shapes. In belt-driven linear motion systems, the motor has to overcome not only the inertia of the applied load, but also the inertia of the belt, pulleys, and motor coupling. Reference A Textbook of Machine Design by R.S.Khurmi and J.K.In order for a motor to accelerate or decelerate a load, it must overcome the load’s inertia, or resistance to change in motion, as explained in Newton’s First Law. The standard values of nominal belt widths are in R10 series, starting from 25 mm upto 63 mm and in R 20 series starting from 71 mm up to 600 mm. ![]() 12 mm for nominal belt widths of 250 to 600 mm.10 mm for nominal belt widths of 125 to 400 mm, and.8 mm for nominal belt widths of 90 to 224 mm,.6.5 mm for nominal belt widths of 50 to 140 mm,.5 mm for nominal belt widths of 35 to 63 mm,.The preferred values of thicknesses are as follows: The standard flat belt thicknesses are 5, 6.5, 8, 10 and 12 mm. Overall design of the setup – The setup involves the initial conditions of the construction, such as the angle which the belt is wrapped around and geometry of the belt and pulley system.This also applies to extremely dry or warm conditions which will evaporate any water naturally found in the belt, nominally making friction greater. Conditions under which the belt and pulleys are operating – The friction between the belt and pulley may decrease substantially if the belt happens to be muddy or wet, as it may act as a lubricant between the surfaces.Construction of the drive-pulley system – This involves strength and stability of the material used, like the pulley, and how greatly it will oppose the motion of the belt or rope.Belting material used – The age of the material also plays a part, where worn out and older material may become more rough or smoother, changing the sliding friction.There are certain factors that help determine the value of the friction coefficient. Table 1 Coefficient of friction between belt and pulley ![]() The following table shows the values of coefficient of friction for various materials of belt and pulley. ![]() ![]() Where, v = Speed of the belt in meters per minute. Barth, the coefficient of friction (μ) for oak tanned leather belts on cast iron pulley, at the point of slipping, is given by the following relation, i.e. The coefficient of friction between the belt and the pulley depends upon the following factors:Īccording to C.G.
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