ISO TS 31657-4-2020 PDF

Full title and description

ISO/TS 31657-4:2020 — Plain bearings — Hydrodynamic plain journal bearings under steady-state conditions — Part 4: Permissible operational parameters for calculation of multi-lobed and tilting pad journal bearings. This technical specification gives guide (permissible) operational parameter values intended to be used together with the calculation procedures of ISO/TS 31657-1 for selected multi-lobed and tilting-pad journal bearings so that calculated characteristic values remain within safe operating margins.

Abstract

This document establishes permissible operational parameters expressed as guide values (empirical, geometrically and technologically founded limits) for the calculation of selected multi‑lobed and tilting‑pad journal bearings. It states that the minimum film thickness characteristic h_min should be well above the permissible threshold h_lim,tr and that calculated peak temperature (T_max) and peak pressure (p_max) should not exceed their corresponding permissible limits (T_lim, p_lim). The guide values are intended to enable sufficient operational safety while allowing modification for special application areas; calculation examples and symbol definitions are referenced in ISO/TS 31657-1.

General information

• Status: Withdrawn (superseded by a published International Standard in 2025).
• Publication date: June 2020 (technical specification published 10 June 2020).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 21.100.10 — Plain bearings.
• Edition / version: Edition 1 (ISO/TS 31657-4:2020).
• Number of pages: 6.

(Status, publication date, ICS and pagination as recorded on the ISO catalogue and commercial standards catalogs.)

Scope

Specifies permissible operational parameters as guide values for calculations of selected multi‑lobed and tilting‑pad hydrodynamic plain journal bearings under steady‑state conditions. The values are empirical and given to ensure sufficient operational safety when using the calculation procedures of ISO/TS 31657-1; they may be adjusted for special applications. The specification applies to oil‑lubricated hydrodynamic journal bearings of the referenced types and provides limiting values for key tribological parameters (film thickness, local temperature and pressure) used during design and assessment.

Key topics and requirements

• Definition and presentation of permissible operational (guide) values for multi‑lobed and tilting‑pad journal bearings.
• Requirement that calculated minimum film thickness (h_min) be significantly greater than the permissible threshold (h_lim,tr) to ensure safe operation.
• Limits for maximum local temperature (T_lim) and maximum local pressure (p_lim) so that calculated T_max and p_max do not exceed them.
• Use of empirical, geometry- and technology‑founded guide values which can be modified for special application areas.
• Reference to ISO/TS 31657-1 for symbols, calculation methodology and worked examples.
• Focus on steady‑state hydrodynamic performance; transient or non‑lubricated conditions are outside the primary scope of this part.

Typical use and users

Engineers and designers of rotating machinery and plain bearings (OEMs for turbines, compressors, electric machines, marine and industrial rotating equipment), tribologists, maintenance engineers assessing bearing retrofit or life‑extension options, test laboratories performing bearing validation, and standards committees. The document is used during bearing design verification, safety margin checks, and as a reference when deriving application‑specific limits from the guide values.

Related standards

Directly linked to and intended for use with ISO/TS 31657-1 (calculation methods and symbols) and other parts of the ISO 31657 series. ISO/TS 31657-4:2020 has been withdrawn and replaced by ISO 31657-4 (International Standard published in 2025). Other related ISO standards on plain bearings and testing (examples: ISO 3547 series, ISO 12167 series and ISO 4386 series) cover dimensions, test methods and specific bearing types and are commonly referenced alongside ISO/TS 31657 parts.

Keywords

plain bearings; hydrodynamic; journal bearings; multi‑lobed bearings; tilting‑pad bearings; permissible operational parameters; guide values; minimum film thickness (h_min); maximum temperature (T_max); maximum pressure (p_max); ISO/TS 31657.

FAQ

Q: What is this standard?

A: ISO/TS 31657-4:2020 is a technical specification that provided guide values for permissible operational parameters used when calculating the hydrodynamic performance of selected multi‑lobed and tilting‑pad plain journal bearings under steady‑state conditions. It has since been superseded by a later ISO publication.

Q: What does it cover?

A: It covers empirical guide values and limiting parameters (film thickness, local temperature and pressure) intended to be used with the calculation methods in ISO/TS 31657-1 to ensure adequate operational safety margins for specified bearing types.

Q: Who typically uses it?

A: Bearing designers, rotating‑machinery OEMs, tribology specialists, maintenance and reliability engineers, test laboratories and standards developers who need standardized guide values for design verification and safety assessments.

Q: Is it current or superseded?

A: ISO/TS 31657-4:2020 was withdrawn and superseded by ISO 31657-4 (published as an International Standard in 2025). Users should refer to the 2025 edition for the current, authoritative text.

Q: Is it part of a series?

A: Yes — it is one part of the ISO 31657 series addressing hydrodynamic plain journal bearings; Part 1 contains calculation procedures and symbol definitions referenced by Part 4.

Q: What are the key keywords?

A: Plain bearings, hydrodynamic, journal bearing, multi‑lobed, tilting‑pad, permissible operational parameters, guide values, film thickness, temperature limit, pressure limit, ISO 31657.