ISO TS 31657-3-2020 PDF

Full title and description

Plain bearings — Hydrodynamic plain journal bearings under steady-state conditions — Part 3: Functions for calculation of tilting pad journal bearings. This technical specification provides characteristic functions and tabulated values used for the design and operational safety assessment of selected tilting‑pad journal bearings (four- or five‑pad designs) under stationary/steady‑state conditions.

Abstract

This document specifies the characteristic values and plotted functions for selected tilting‑pad journal bearings with four or five centrally or eccentrically supported pads and angular pad spans Ω = 80°, 60° and 45°. The functions are intended to be used together with the general calculation method and symbol definitions given in Part 1 of the series and apply only to stationary operating states; calculation examples and symbol explanations are referenced in Part 1.

General information

• Status: Withdrawn (superseded by a 2025 edition of the Part 3 standard).
• Publication date: June 2020 (published mid‑2020).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.100.10 (Plain bearings).
• Edition / version: Edition 1 (ISO/TS 31657‑3:2020).
• Number of pages: 73 pages.

Details above are based on the ISO bibliographic record for ISO/TS 31657‑3:2020. The Part 3 technical specification was later replaced by an ISO International Standard edition titled ISO 31657‑3:2025.

The formal withdrawal / replacement was recorded in national catalogues (withdrawal / replacement effective dates shown in national records).

Scope

Specifies characteristic values (dimensionless functions and tabulated data) for selected tilting‑pad journal bearings to be used in hydrodynamic steady‑state calculations. The scope is limited to stationary operating conditions and to the specific bearing geometries and pad angular spans listed; it does not address unsteady or transient conditions. The functions are intended to support safe operational design when used in conjunction with the calculation procedures and symbol definitions of Part 1 of the ISO 31657 series.

Key topics and requirements

• Provision of characteristic functions and tabulated values for tilting‑pad journal bearings (four‑ and five‑pad designs).
• Data given for pad angular spans Ω = 80°, 60° and 45° relevant to common tilting‑pad geometries.
• Application restricted to steady‑state (stationary) operating conditions; unsteady phenomena are outside the scope.
• Intended usage alongside ISO/TS (now ISO) 31657‑1 calculation procedures and symbol definitions.
• Designed to support operational safety margins and to provide inputs for design, load capacity, temperature and minimum film thickness estimations in bearing calculations.

Typical use and users

Mechanical and rotating‑machinery design engineers, bearing designers, tribologists, maintenance engineers for turbines/compressors/generators, standards specialists and test laboratories use these functions when performing hydrodynamic design and verification of tilting‑pad journal bearings. The data are typically used in design offices, OEMs for rotating equipment, and by standards/technical committees when harmonizing calculation procedures for plain bearings.

Related standards

ISO/TS 31657‑1 (calculation method and symbols) and ISO/TS 31657‑2 (functions for multi‑lobed bearings) are the immediately related parts of the series; ISO/TS 31657‑4 covers permissible operational guide values for multi‑lobed and tilting‑pad bearings. The 2020 technical specifications in the 31657 series have subsequently been revised and published as ISO 31657 parts in 2025 (each part published as an International Standard).

Keywords

tilting‑pad journal bearings; plain bearings; hydrodynamic lubrication; steady‑state; characteristic functions; bearing design; ISO 31657; multi‑lobed bearings; pad angular span; tribology.

FAQ

Q: What is this standard?

A: ISO/TS 31657‑3:2020 is a technical specification that provided characteristic functions and tabulated values for the calculation of selected tilting‑pad journal bearings under steady‑state conditions. It has been superseded by a later ISO edition (Part 3 published in 2025).

Q: What does it cover?

A: It covers characteristic values (dimensionless functions and tables) for four‑ and five‑pad tilting‑pad journal bearings with pad spans Ω = 80°, 60° and 45°, intended for steady‑state hydrodynamic calculations used in design and safety assessment.

Q: Who typically uses it?

A: Bearing designers, rotating machinery engineers (turbines, compressors, generators, pumps), tribologists, test laboratories and standards committees—anyone performing hydrodynamic design or verification of tilting‑pad journal bearings.

Q: Is it current or superseded?

A: The 2020 technical specification (ISO/TS 31657‑3:2020) was withdrawn and superseded by ISO 31657‑3 (published as the 2025 edition). National catalogues record the withdrawal/replacement; consult published ISO bibliographic records or your national standards body for the exact effective withdrawal/replacement dates.

Q: Is it part of a series?

A: Yes. It is Part 3 of the ISO 31657 series (multi‑part standard addressing hydrodynamic plain journal bearings under steady‑state conditions). The series includes the calculation method/symbols (Part 1), functions for multi‑lobed bearings (Part 2), this Part 3 (tilting‑pad functions) and guidance on permissible operational parameters (Part 4). Several parts were originally issued as ISO/TS (2020) and later published/updated as ISO International Standards (2025 editions).

Q: What are the key keywords?

A: Tilting‑pad journal bearings; plain bearings; hydrodynamic; steady‑state; functions; characteristic values; ISO 31657; bearing design; pad span; tribology.