ISO 12130-1:2021

INTERNATIONAL ISO
STANDARD 12130-1
Second edition
2021-04
Plain bearings — Hydrodynamic plain
tilting pad thrust bearings under
steady-state conditions —
Part 1:
Calculation of tilting pad thrust
bearings
Paliers lisses — Butées hydrodynamiques à patins oscillants
fonctionnant en régime stationnaire —
Partie 1: Calcul des butées à patins oscillants
Reference number
©
ISO 2021
© ISO 2021
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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

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 Fundamentals, assumptions and premises . 5
6 Calculation procedure . 6
6.1 Loading operations . 6
6.1.1 General. 6
6.1.2 Wear . 6
6.1.3 Mechanical loading . 6
6.1.4 Thermal loading . 6
6.1.5 Outside influences . 6
6.2 Coordinate of centre of pressure . 7
6.3 Load-carrying capacity . 7
6.4 Frictional power. 9
6.5 Lubricant flow rate . 9
6.6 Heat balance .10
6.6.1 General.10
6.6.2 Heat dissipation by convection .10
6.6.3 Heat dissipation by recirculating lubrication .11
6.6.4 Mixing processes in the lubrication recess .11
6.7 Minimum lubricant film thickness and specific bearing load .13
6.8 Operating conditions .13
6.9 Further influence factors .14
Annex A (informative) Examples of calculation .15
Bibliography .24
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 second edition cancels and replaces the first edition (ISO 12130-1:2001), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— addition of Introduction;
— correction of numerical values in Table A.5;
— adjustment to ISO/IEC Directives, Part 2:2018;
— correction of typographical errors.
A list of all parts in the ISO 12130 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 2021 – All rights reserved

Introduction
The aim of the ISO 12130 series is to achieve designs of plain bearings that are reliable in operation by
the application of a calculation method for oil-lubricated hydrodynamic plain bearings with complete
separation of the thrust collar and plain bearing surfaces by a film of lubricant.
The calculation method described in this document can be used for other gap shapes, e.g. parabolic
lubrication clearance gaps, as well as for other types of sliding blocks, e.g. circular sliding blocks, when
for these types the numerical solutions of Reynolds equation are present. ISO 12130-2 gives only the
characteristic values for the plane wedge-shaped gap; the values are therefore not applicable to tilting
pads with axial support.
The calculation method serves for designing and optimizing plain thrust bearings e.g. for fans, gear
units, pumps, turbines, electric machines, compressors and machine tools. It is limited to steady-state
conditions, i.e. load and angular speed of all rotating parts are constant under continuous operating
conditions.
INTERNATIONAL STANDARD ISO 12130-1:2021(E)
Plain bearings — Hydrodynamic plain tilting pad thrust
bearings under steady-state conditions —
Part 1:
Calculation of tilting pad thrust bearings
1 Scope
This document specifies a calculation method for oil-lubricated hydrodynamic plain bearings with
complete separation of the thrust collar and tilting pad thrust bearing surfaces by a film of lubricant.
This document applies to plain thrust bearings with tilting-type sliding blocks (tilting pads), where a
wedge-shaped lubrication clearance gap is automatically formed during operation. The ratio of width
to length of one pad can be varied in the range B/L = 0,5 to 2.
This document is not applicable to heavily loaded tilting pad thrust bearings.
NOTE Equivalent calculation procedures exist that enable operating conditions to be estimated and checked
against acceptable conditions. The use of them is equally admissible.
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 12130-2, Plain bearings — Hydrodynamic plain tilting pad thrust bearings under steady-state
conditions — Part 2: Functions for calculation of tilting pad thrust bearings
ISO 12130-3, Plain bearings — Hydrodynamic plain tilting pad thrust bearings under steady-state
conditions — Part 3: Guide values for the calculation of tilting pad thrust bearings
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 Symbols, terms and units
Symbols, terms and units are shown in Table 1 and Figure 1.
Table 1 — Symbols, terms and units
Symbol Term Unit
a distance between supporting point and inlet of the clearance gap in the m
F
direction of motion (circumferential direction)
Table 1 (continued)
Symbol Term Unit
* relative distance between supporting point and inlet of the clearance gap in 1
a
F
the direction of motion (circumferential direction)
A heat-emitting surface of the bearing housing m
B width of one pad m
B axial housing width m
H
Cp specific heat capacity of the lubricant (p = constant) J/(kg⋅K)
C wedge depth m
wed
D mean sliding diameter m
D housing outside diameter m
H
D inside diameter over tilting pads m
i
D outside diameter over tilting pads m
o
f* characteristic value of friction 1
F bearing force (load) at nominal rotational frequency N
F* characteristic value of load carrying capacity 1
F bearing force (load) at standstill N
st
h local lubricant film thickness (clearance gap height) m
h minimum permissible lubricant film thickness during operation m
lim
h minimum permissible lubricant film thickness on transition into mixed m
lim,tr
lubrication
h minimum lubricant film thickness (minimum clearance gap height) m
min
k heat transfer coefficient related to the product B · L · Z W/(m ⋅K)
k external heat transfer coefficient (reference surface A) W/(m ⋅K)
A
L length of one pad in circumferential direction m
M mixing factor 1
-1
N rotational frequency (speed) of thrust collar s
p local lubricant film pressure Pa
p Pa
specific bearing load pF=⋅/()BL⋅Z
maximum permissible specific bearing load Pa
p
lim
P frictional power in the bearing or power generated heat flow rate W
f
P heat flow rate to the environment W
th,amb
heat flow rate arising from the friction power W
P
th,f
P heat flow rate in the lubricant W
th,L
Q lubricant flow rate m /s
Q* characteristic value of lubricant flow rate 1
Q m /s
relative lubricant flow rate QB=⋅hU⋅⋅Z
0 min
Q lubricant flow rate at the inlet of the clearance gap (circumferential direction) m /s
*
characteristic value of lubricant flow rate at the inlet of the clearance gap 1
Q
Q lubricant flow rate at the outlet of the clear
...