BS ISO 7902-1:2020 pdf free.Hydrodynamic plain journal bearings under steady-state conditions一Circular cylindrical bearings
Calculation procedure.
BS ISO 7902-1 This document specifies a calculation procedure for oil-lubricated hydrodynamic plain bearings, with complete separation of the shaft and bearing sliding surfaces by a film of lubricant, used for designing plain bearings that are reliable in operation.It deals with circular cylindrical bearings having angular spans, 2, of 360, 180°, 150°, 120°, and 90° the arc segment being loaded centrally. Their clearance geometry is constant except for negligible deformations resulting from lubricant film pressure and temperature.The calculation procedure serves to provide dimensions and optimize plain bearings in turbines,generators, electric motors, gear units, rolling mills, pumps, and other machines. It is limited to steady-state operation, i.e. under continuously driven operating conditions, with the magnitude and direction of loading as well as the angular speeds of all rotating parts constant. It can also be applied if a full plain bearing is subjected to a constant force rotating at any speed. Dynamic loadings (i.e. those whose
magnitude and direction vary with time), such as those that can result from vibration effects and instabilities of rapid-running rotors, are not taken into account. NOTE Equivalent calculation procedures exist that enable operating conditions to be estimated and checked against acceptable conditions. The use of them is equally admissible.The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 7902-2, Hydrodynamic plain journal bearings under steady-state conditions一Circular cylindrical bearings一Part 2: Functions used in the calculation procedure ISO 7902-3, Hydrodynamic plain journal bearings under steady-state conditions – 一Circular cylindrical
bearings一Part 3: Permissible operational parameters.The application of the similarity principle to hydrodynamic plain bearing theory results in dimensionless magnitudes of similarity for parameters of interest, such as load-carrying capacity, frictional behaviour,
lubricant flow rate and relative bearing length. The application of magnitudes of similarity reduces the number of numerical solutions required of Reynolds equation specified in ISO 7902-2. Other solutions may also be applied, provided they fulfil the conditions laid down in ISO 7902-2 and are of a similar numerical accuracy.BS ISO 7902-1 pdf download.