The aim of this part of ISO 12131 is to achieve designs of plain bearings that are reliable in operation, by the application of a calculation method for oil-lubricated hydrodynamic plain bearings with complete separation of the thrust collar and plain bearing surfaces by a film of lubricant ^[1].

This part of ISO 12131 applies to plain thrust bearings with incorporated wedge and supporting surfaces having any ratio of wedge surface length l_wed to length of one padL. It deals with the valuel_wed/L= 0,75 as this valuerepresents the optimum ratio ^[2]. The ratio of width to length of one pad can be varied in the range B/L = 0,5 to 2.

The calculation method described in this part of ISO 12131 can be used for other incorporated gap shapes, e.g. plain thrust bearings with integrated baffle, when for these types the numerical solutions of Reynolds' differential equation are known.

The calculation method serves for designing and optimizing plain thrust bearings e.g. for fans, gear units, pumps, turbines, electrical machines, compressors and machine tools. It is limited to steady-state conditions, i.e. load and angular speed of all rotating parts are constant under continuous operating conditions. Dynamic operating conditions are not included.