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 document establishes the permissible operational parameters in terms of guide values for the calculation of selected multi-lobed and tilting-pad journal bearings. In order to attain a sufficient operational safety of multi-lobed and tilting-pad journal bearings by the calculation according to ISO/TS 31657-1, it is necessary for the operational characteristic value hmin to be significantly above the permissible operating parameter hlim,tr and for the permissible operating parameters Tlim and plim not to be exceeded by the calculated operational characteristic values Tmax and pmax. The guide values represent geometrically and technologically founded operational limiting values in the tribological system of plain bearings. They are empirical values that enable sufficient operational safety even in the event of smaller disturbing influences (see ISO/TS 31657-1). The empirical values indicated can be modified for special application areas. NOTE The explanations for the symbols and calculation examples are contained in ISO/TS 31657-1.

titre manque — Partie 4: titre manque

General Information

• Status: Published
• Publication Date: 09-Jun-2020
• ICS: 21.100.10 - Plain bearings
• Technical Committee: ISO/TC 123/SC 8 - Calculation methods for plain bearings and their applications
• Drafting Committee: ISO/TC 123/SC 8 - Calculation methods for plain bearings and their applications
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 16-Oct-2025
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 31657-4:2025 - 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
• Effective Date: 10-Feb-2024

ISO/TS 31657-4:2020 Overview

ISO/TS 31657-4:2020 is an International Standard providing technical specifications for hydrodynamic plain journal bearings, specifically focusing on multi-lobed and tilting pad journal bearings under steady-state conditions. This part of the ISO/TS 31657 series establishes permissible operational parameters, expressed as guide values, that are critical for safe and reliable calculation and performance assessment of these bearing types.

The key emphasis of this specification lies in ensuring operational safety by defining limits for lubricant film thickness, bearing clearance, load, and temperature during bearing operation. These empirical guide values are derived from geometrical, technological, and tribological considerations and serve as authoritative reference points for design engineers and maintenance professionals involved in bearing calculation and application.

Key Topics Covered

• Permissible Operational Parameters: The standard defines critical operational limits including minimum lubricant film thickness (h_min), maximum allowable temperature (T_lim), and maximum pressure (p_lim) that must not be exceeded to avoid bearing damage.

• Transition to Mixed Friction: Special attention is given to the transition phase from hydrodynamic lubrication to mixed friction, detailing acceptable sliding speeds (U) and lubricant film thickness values to prevent wear or damage during start-up and shut-down.

• Material Selection and Surface Conditions: Guidance is provided on material hardness differences and surface roughness to optimize running-in conditions and ensure durable bearing performance.

• Thermal and Mechanical Load Avoidance: The standard outlines temperature-dependent maximum pressures for different bearing materials, reflecting how thermal conditions influence bearing strength and lifespan.

• Bearing Clearance Optimization: Operational guide values for bearing clearance, profile factors, and gap ratios are included to improve guiding accuracy, cooling performance, and overall bearing stability.

• Lubrication and Filtration: The significance of lubricant cleanliness and appropriate oil filtration to maintain a sufficient lubricant film thickness in dynamic operation is emphasized.

Practical Applications

ISO/TS 31657-4:2020 serves as a vital resource for industries and engineers involved in:

• Design and Calculation of Bearings: Assisting mechanical and tribology engineers in selecting and calculating multi-lobed and tilting pad journal bearings that meet operational safety and efficiency criteria.

• Maintenance and Condition Monitoring: Offering parameters to evaluate bearing condition during start-up, shut-down, and steady operation, helping to anticipate wear and prevent failures.

• Lubrication System Design: Guiding lubricant type selection, filtration specifications, and circulation system design for optimal bearing performance and longevity.

• Material Engineering and Manufacturing: Informing choices related to bearing and journal material combinations, hardness differences, and finishing processes to enhance bearing running-in and reduce friction.

• Thermal Management: Enabling the development of bearing systems that effectively manage temperature rise, avoiding mechanical overloading and lubricant degradation under diverse operating conditions.

Related Standards

Professionals should consider ISO/TS 31657-4:2020 alongside related standards from the ISO/TS 31657 series and others that collectively guide plain bearing design and application, including:

• ISO/TS 31657-1: Calculation methodologies for multi-lobed and tilting-pad journal bearings.

• ISO/TS 31657-2: Calculation functions specifically for multi-lobed journal bearings.

• ISO/TS 31657-3: Calculation functions for tilting-pad journal bearings.

• ISO 4381, ISO 4382-1/2, and ISO 4383: Standards covering materials and multilayer constructions for plain bearings.

• VDI Richtlinie 2204: Recommendations related to bearing lubrication technology.

Integrating the operational guide values from ISO/TS 31657-4:2020 with these complementary standards ensures comprehensive understanding and control over bearing design parameters, enhancing system reliability and performance.

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Keywords: ISO/TS 31657-4:2020, hydrodynamic plain journal bearings, multi-lobed journal bearings, tilting pad bearings, permissible operational parameters, bearing calculation, lubricant film thickness, bearing clearance, bearing temperature limits, tribology, bearing material selection, thermal management in bearings, bearing design standards, plain bearing lubrication.

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 31657-4
First edition
2020-06
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
Reference number
©
ISO 2020
© ISO 2020
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Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Operational guide values for start-up and run-down . 1
5 Operational guide values for avoiding thermal and mechanical overloading .4
6 Operational guide values for the bearing clearance . 5
Bibliography . 6
Foreword
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This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 8,
Calculation methods for plain bearings and their applications.
A list of all parts in the ISO/TS 31657 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

TECHNICAL SPECIFICATION ISO/TS 31657-4:2020(E)
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
1 Scope
This document establishes the permissible operational parameters in terms of guide values for the
calculation of selected multi-lobed and tilting-pad journal bearings.
In order to attain a sufficient operational safety of multi-lobed and tilting-pad journal bearings by the
calculation according to ISO/TS 31657-1, it is necessary for the operational characteristic value h
min
to be significantly above the permissible operating parameter h and for the permissible operating
lim,tr
parameters T and p not to be exceeded by the calculated operational characteristic values T
lim lim max
and p .
max
The guide values represent geometrically and technologically founded operational limiting values in
the tribological system of plain bearings.
They are empirical values that enable sufficient operational safety even in the event of smaller
disturbing influences (see ISO/TS 31657-1). The empirical values indicated can be modified for special
application areas.
NOTE The explanations for the symbols and calculation examples are contained in ISO/TS 31657-1.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Operational guide values for start-up and run-down
The minimum lubricant film thickness, h , is calculated for the operating point. Its size primarily
min
determines the requirements for the lubricant with respect to its cleanliness and defines the fineness of
the oil filter to be used.
At the transition of a hydrodynamic plain bearing into mixed friction, the minimum lubricant film
thickness, h , at the transition sliding speed, U , attains the value h .
min tr min,tr
In the range 0 < U < U the load percentage carried by solid body contact increases significantly with
tr
decreasing rotational frequency.
It depends on the energy density occurring in the contact area whether a permissible fine wear occurs
on the slidi
...