ISO 12131-2:2023

Plain bearings — Hydrodynamic plain thrust pad bearings under steady-state conditions — Part 2: Functions for the calculation of thrust pad bearings

This document specifies functions for thrust pad bearings. It also covers the effect of dynamic viscosity on lubricant film temperature.

Paliers lisses — Butées hydrodynamiques à patins géométrie fixe fonctionnant en régime stationnaire — Partie 2: Fonctions pour le calcul des butées à segments

General Information

• Status: Published
• Publication Date: 07-Jun-2023
• 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: 6060 - International Standard published
• Start Date: 08-Jun-2023
• Due Date: 13-Jul-2023
• Completion Date: 08-Jun-2023

Relations

• Revises: ISO 12131-2:2016 - Plain bearings — Hydrodynamic plain thrust pad bearings under steady-state conditions — Part 2: Functions for the calculation of thrust pad bearings
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12131-2
Third edition
2023-06
Plain bearings — Hydrodynamic plain
thrust pad bearings under steady-
state conditions —
Part 2:
Functions for the calculation of thrust
pad bearings
Paliers lisses — Butées hydrodynamiques à patins géométrie fixe
fonctionnant en régime stationnaire —
Partie 2: Fonctions pour le calcul des butées à segments
Reference number
ISO 12131-2:2023(E)
© ISO 2023

---------------------- Page: 1 ----------------------
ISO 12131-2:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2023 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 12131-2:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols, terms and units .1
5 Functions for the thrust pad bearing . 2
5.1 Load carrying capacity . 2
5.2 Friction for thrust pad bearings . 4
5.3 Relative lubricant flow rates . 6
6 Effective dynamic viscosity of the lubricant, η , as a function of the effective
eff
lubricant film temperature, T . 9
eff
Bibliography .11
iii
© ISO 2023 – All rights reserved

---------------------- Page: 3 ----------------------
ISO 12131-2:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 8,
Calculation methods for plain bearings and their applications.
This third edition cancels and replaces the second edition (ISO 12131-2:2016), which has been
technically revised.
The main changes are as follows:
— Formula (1) has been corrected;
— Table 1 has been added;
— some editorial corrections have been made.
A list of all parts in the ISO 12131 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 2023 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 12131-2:2023(E)
Introduction
Assuming hydrodynamic conditions with full lubrication, the functions of the type covered by this
document are necessary for the calculation of oil-lubricated pad thrust bearings in accordance with
ISO 12131-1. They are based on the premises and boundary conditions specified. The values necessary
for the calculation can be determined by means of the given formulae, as well as from diagrams and
tables. The formulae in this document are approximations of the numerically determined values traced
as curves according to Reference [2]. The explanation of the symbols, as well as examples for the
calculation, are included in ISO 12131-1.
v
© ISO 2023 – All rights reserved

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 12131-2:2023(E)
Plain bearings — Hydrodynamic plain thrust pad bearings
under steady-state conditions —
Part 2:
Functions for the calculation of thrust pad bearings
1 Scope
This document specifies functions for thrust pad bearings. It also covers the effect of dynamic viscosity
on lubricant film temperature.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 12131-1:2020, Plain bearings — Hydrodynamic plain thrust pad bearings under steady-state conditions
— Part 1: Calculation of thrust pad bearings
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols, terms and units
Symbols and units are defined in Table 1. Any symbols not listed in Table 1 shall be defined in accordance
with ISO 12131-1:2020, Table 1.
Table 1 — Symbols, terms, and units
Symbol Term Unit
i (index) Consecutive number 1
*
A , A , A , A Auxiliary quantity 1
1 3 i
*
B , B , B , B Auxiliary quantity 1
1 3 i
*
C Auxiliary quantity 1
K “Thickness” of oil Pa·s
1
K Inherent viscosity-temperature dependence of oil °C
2
K Oil temperature for infinite viscosity °C
3
VG ISO Viscosity Grade 1
α Auxiliary quantity 1
η Constant coefficient Pa·s
x
1
© ISO 2023 – All rights reserved

---------------------- Page: 6 ----------------------
ISO 12131-2:2023(E)
5 Functions for the thrust pad bearing
5.1 Load carrying capacity
*
Characteristic value of load carrying capacity, F , as a function of the relative bearing length, B/L, and
B
the relative minimum lubricant film thickness, h /C is defined by Formula (1) using the auxiliary
min wed
* * *
quantities α, A , B and C .
Approximation of the curves of Figure 1 (range of application: 0,1 ≤ h /C ≤ 10).
min wed
2
2
 
l  h  1 + hC/
 
wed min min wed
 ×  × ln 
   
L C h /C
 
   
wed miin wed
 


*
 
2 2
F =×5
B
l 1 l l  h l 
       
wed wedwed min wed
 ×
...

DRAFT INTERNATIONAL STANDARD
ISO/DIS 12131-2
ISO/TC 123/SC 8 Secretariat: JISC
Voting begins on: Voting terminates on:
2022-09-15 2022-12-08
Plain bearings — Hydrodynamic plain thrust pad bearings
under steady-state conditions —
Part 2:
Functions for the calculation of thrust pad bearings
Paliers lisses — Butées hydrodynamiques à patins géométrie fixe fonctionnant en régime stationnaire —
Partie 2: Fonctions pour le calcul des butées à segments
ICS: 21.100.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
This document is circulated as received from the committee secretariat.
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 12131-2:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

---------------------- Page: 1 ----------------------
ISO/DIS 12131-2:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 12131-2
ISO/TC 123/SC 8 Secretariat: JISC
Voting begins on: Voting terminates on:

Plain bearings — Hydrodynamic plain thrust pad bearings
under steady-state conditions —
Part 2:
Functions for the calculation of thrust pad bearings
Paliers lisses — Butées hydrodynamiques à patins géométrie fixe fonctionnant en régime stationnaire —
Partie 2: Fonctions pour le calcul des butées à segments
ICS: 21.100.10
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2022
THEREFORE SUBJECT TO CHANGE AND MAY
This document is circulated as received from the committee secretariat.
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on STANDARD UNTIL PUBLISHED AS SUCH.
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
IN ADDITION TO THEIR EVALUATION AS
or ISO’s member body in the country of the requester. BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
ISO copyright office
USER PURPOSES, DRAFT INTERNATIONAL
CP 401 • Ch. de Blandonnet 8
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
CH-1214 Vernier, Geneva
POTENTIAL TO BECOME STANDARDS TO
Phone: [phone]
WHICH REFERENCE MAY BE MADE IN
Reference number
Email: [e-mail]
NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 12131-2:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
Published in Switzerland
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
ii
  © ISO 2022 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

---------------------- Page: 2 ----------------------
ISO/DIS 12131-2:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols, terms and units .1
5 Functions for the thrust pad bearing . 2
5.1 Load carrying capacity . 2
5.2 Friction for thrust pad bearings . 4
5.3 Relative lubricant flow rates . 6
6 Effective dynamic viscosity of the lubricant, η , as a function of the effective
eff
lubricant film temperature, T . 9
eff
Annex A (informative) Comparison ISO VG viscosity grades versus SAE viscosity classes .11
Bibliography .12
iii
© ISO 2022 – All rights reserved

---------------------- Page: 3 ----------------------
ISO/DIS 12131-2:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/
iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 8,
Calculation methods for plain bearings and their applications.
This third edition cancels and replaces the second edition (ISO 12131-2:2016), which has been
technically revised.
The main changes are as follows:
— adjustments have been made to ISO/IEC Directives, Part 2:2021;
— typographical errors have been corrected.
A list of all parts in the ISO 12131 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 2022 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/DIS 12131-2:2022(E)
Introduction
Assuming hydrodynamic conditions with full lubrication, the functions of the type covered by this
document are necessary for the calculation of oil-lubricated pad thrust bearings in accordance with
ISO 12131-1. They are based on the premises and boundary conditions specified. The values necessary
for the calculation can be determined by means of the given formulae, as well as from diagrams and
tables. The formulae in this document are approximations of the numerically determined values traced
as curves according to Reference [2]. The explanation of the symbols, as well as examples for the
calculation, are included in ISO 12131-1.
v
© ISO 2022 – All rights reserved

---------------------- Page: 5 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 12131-2:2022(E)
Plain bearings — Hydrodynamic plain thrust pad bearings
under steady-state conditions —
Part 2:
Functions for the calculation of thrust pad bearings
1 Scope
This document specifies functions for thrust pad bearings. It also covers the effect of dynamic viscosity
on lubricant film temperature.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 12131-1, Plain bearings — Hydrodynamic plain thrust pad bearings under steady-state conditions —
Part 1: Calculation of thrust pad bearings
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols, terms and units
Symbols and units are defined in Table 1. The symbols not listed in Table 1 can be referenced in Table 1
of ISO
...