Hydrodynamic plain journal bearings under steady-state conditions — Circular cylindrical bearings Part 1: Calculation procedure Published (Edition 4, 2026)

Abstract

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, Ω, 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.

General information

Status : Published

Publication date : 2026-05

Stage : International Standard published

Edition : 4

Number of pages : 32

ISO

ISO 11949:2026

ISO 10993-6:2026

ISO 11228-3:2026

ISO 17978-1:2026

ISO 7902-1:2026

ISO 9139:2026

ISO 6941:2026

ISO 24675-2:2026

ISO 15747:2026

ISO 8549-4:2026

ISO 19307:2026

ISO 22915-8:2026