ISO/DIS 3548-1

Plain bearings -- Thin-walled half bearings with or without flange

Paliers lisses -- Demi-coussinets minces à ou sans collerette

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 3548-1
ISO/TC 123/SC 3 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-01-08 2021-04-02
Plain bearings — Thin-walled half bearings with or
without flange —
Part 1:
Tolerances, design features and methods of test
Paliers lisses — Demi-coussinets minces à ou sans collerette —
Partie 1: Tolérances, caractéristiques de conception et méthodes d'essai
ICS: 21.100.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
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 3548-1:2021(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 2021
---------------------- Page: 1 ----------------------
ISO/DIS 3548-1:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© 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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/DIS 3548-1:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 1

5 Dimensions and tolerances ....................................................................................................................................................................... 3

5.1 Housing diameter, half bearing outside diameter and crush height......................................................... 3

5.2 Half bearing wall thickness and bearing bore ............................................................................................................. 4

5.3 Width of half bearing, distance between flanges, outside diameter of flange and

flange thickness ...................................................................................................................................................................................... 5

5.4 Free spread ................................................................................................................................................................................................. 6

6 Design features....................................................................................................................................................................................................... 7

6.1 General ........................................................................................................................................................................................................... 7

6.2 Locating nick and recess ................................................................................................................................................................. 8

6.3 Reliefs and chamfers .......................................................................................................................................................................... 9

6.4 Transition between radial part and flange ..................................................................................................................10

6.5 Assembled flange scalloped toes ..........................................................................................................................................12

6.6 Oil grooves and holes ......................................................................................................................................................................12

7 Test data for determining the peripheral length .............................................................................................................15

7.1 Calculation of test force F............................................................................................................................................................15

7.2 Checking method A ..........................................................................................................................................................................16

7.3 Checking method B ......... ..................................................................................................................................................................17

8 Test data for determining axial width, B , of flange bearings .............................................................................17

8.1 General ........................................................................................................................................................................................................17

8.2 Go between two parallel plates..............................................................................................................................................17

8.3 Axial width B2 checked under force ..................................................................................................................................18

9 Function and characteristics of assembled flange bearings ................................................................................19

9.1 General ........................................................................................................................................................................................................19

9.2 Characteristics ......................................................................................................................................................................................19

9.3 Classification ..........................................................................................................................................................................................20

9.4 Checklist of items for ensuring the function of assembled flange bearings ....................................20

Bibliography .............................................................................................................................................................................................................................22

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/DIS 3548-1:2021(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. 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. 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 on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO's adherence to the WTO principles in the Technical

Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information

The committee responsible for this document is ISO/TC 123, Plain Bearings, Subcommittee SC 3 Dimen-

sions, tolerances and constructions details.,

This second edition of ISO 3548-1 cancels and replaces the first edition of ISO 3548:2014, which has

been technically revised.
iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 3548-1:2021(E)
Plain bearings — Thin-walled half bearings with or
without flange —
Part 1:
Tolerances, design features and methods of test
1 Scope

This documents specifies tolerances, design features, and test methods for thin-walled half bearings

with integral flange up to an outside diameter of D = 250 mm and without flange up to an outside

diameter of D = 500 mm. Due to the variety of design, it is, however, not possible to standardize the

dimensions of the half bearings.

Half bearings according to this document are predominantly used in reciprocating machinery and

consist of a steel backing and one or more bearing metal layers on the inside.

In reciprocating machinery, flanged half bearings can be used in connection with half bearings

without flange.

Alternatively, to serve as a flanged half bearing, it is possible to use a half bearing without flange

together with two separate half thrust washers according to ISO 6526; or a half bearing with assembled

flanges.
NOTE All dimensions and tolerances are given in millimetres.
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 4288, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Rules and

procedures for the assessment of surface texture

ISO 6524, Plain bearings — Thin-walled half bearings — Checking of peripheral length

ISO 6526, Plain bearings — Pressed bimetallic half thrust washers — Features and tolerances

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
Symbols, terms and units are shown in Figures 1 and 2 and Table 1.
© ISO 2021 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO/DIS 3548-1:2021(E)
Key
1 joint face
2 sliding surface
3 bearing metal
4 bearing back
5 steel back
Figure 1 — Half bearing without flange
(with positive free spread)
Figure 2 — Flange half bearing
(integral or assembled, excluding free spread)
Table 1 — Symbols and units
Symbol Term Unit
a Measuring point perpendicular to plane of joint face mm
2 © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/DIS 3548-1:2021(E)
Table 1 (continued)
Symbol Term Unit
A Reduced area of cross section (calculated value) of half bearing mm
cal
b Housing width mm
B Half bearing width (without flange) mm
B Flange half bearing width mm
B Distance between flanges mm
C Outside chamfer mm
C Inside chamfer mm
d Diameter of the checking block bore mm
d Housing diameter mm
D Outside diameter of flange mm
D Nominal Inside diameter of the half bearing (bearing bore) mm
D Nominal Outside diameter of the half bearing mm
D Outside diameter of the half bearing in the free state (with free spread) mm
o,E
e Amount of eccentricity mm
F Test force N
F Axial test force for assembled flange bearings N
h Crush height, h = h + h (in checking method B) mm
1 2
p Amount of free spread mm
s Flange thickness mm
s Thickness of the steel backing mm
s Bearing metal thickness mm
s Half bearing wall thickness mm
s Wall thickness at base of groove mm
u Amount of wall thickness reduction for eccentric bearing mm
5 Dimensions and tolerances
5.1 Housing diameter, half bearing outside diameter and crush height

The housing diameter should be manufactured to ISO H6 limits. Thereby the half bearing outside

diameter shall be selected with such an oversize that an adequate interference fit is ensured in the

housing diameter.

In the case of housings made from materials having a high coefficient of expansion or where other

factors such as housing dimensional stability are involved, the housing size may depart from tolerance

class H6 but shall always be produced in accordance with a grade 6 tolerance.

The half bearing in a free state is flexible so that its outside diameter cannot be measured directly.

Instead of this, its peripheral length is determined by means of special checking fixtures. The peripheral

length results from the periphery of the checking block bore and the crush height taking into account

the reduction under a given checking load per joint face (see Clause 6). For the calculation of the effective

interference fit of the half bearings in the housing, see Reference [5].

The tolerances given in Table 2 for the crush height apply to half bearings with machined joint faces.

Different materials and housing design require different interference fits, therefore only tolerances are

given in Table 2.
© ISO 2021 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO/DIS 3548-1:2021(E)
5.2 Half bearing wall thickness and bearing bore

Nominal dimensions to be preferred for the wall thickness of the bearing are given in Table 2 (the

particulars of the wall thickness for each application cannot be specified in general). Therefore, only

tolerances can be given for the wall thickness. These tolerances and the surface roughnesses of the

bearing back and the sliding surface of half bearings with or without electroplated antifriction layers

are given in Table 2.

The tolerance for the half bearing wall thickness depends on the fact whether the bearing bore is

subject to a final machining operation (i.e. “as machined”) or whether the bearing bore is electroplated

without further machining (i.e. “as-plated”).

Slight surface deformations are acceptable on the outside diameter of the bearing provided that they are

not numerous. However, the measurement of the wall thickness shall not be carried out in these areas.

The bearing bore in the fitted state results from the housing bore which is elastically enlarged by the

[5]
press fit, reduced by twice the value of the half bearing wall thickness.

NOTE In certain applications it might be necessary to use plain or flange half bearings with eccentric bores, i.e.

the wall thickness of the half bearing decreases uniformly from the crown to the joint faces (see Figures 3 and 4).

The eccentricity e is characterized in a radial plane by the distance between the centre x of the

B 1

bearing outside surface and the centre x of the bearing bore. e is not dimensioned specifically. The

2 B

eccentricity is controlled by the specified reduction u which is measured at a vertical distance a from

the plane of the joint face. (For guidance of draughtsmen, a is generally specified so that the angle α is

1 2

approximately 25° from the joint face). It is subject to agreement between the user and manufacturer.

Figure 3 — Eccentric bearing bore of half bearing
4 © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/DIS 3548-1:2021(E)
Key
1 crown
2 joint face
Figure 4 — Example of the wall thickness at different angles

The tolerance limit for the behaviour of wall thickness can be calculated using Formulae 1 and 2:

1 − sinα
_= s × (1)
s BL
α ,BL u
3,act
1 − sin
1 − sinα
ss=− UL × (2)
α, 3, act
UL 1 − sinα
where
BL is the bottom limit of u;
UL is the upper limit of u;
s is the actual value of s ;
3, act 3
s is the bottom value of s ;
α, BL α
s is the upper value of s .
α, UL α

5.3 Width of half bearing, distance between flanges, outside diameter of flange and

flange thickness

The nominal dimension for the half bearing width and the distance between flanges depends upon the

type of application, the common ratio being B (B )/D ≤ 0,5. The tolerances for the half bearing width

1 2 i

are given in Table 2. The flange outside diameter should be smaller than the diameter of the shoulder of

the shaft and smaller than the diameter of the housing block.

In most cases the flange thickness is fixed in conformity with the half bearing wall thickness and, in

general, a tolerance is fixed only for the flange thickness of the pressure loaded side in order to ensure

that these flanges of the upper and lower half bearing have approximately the same thickness. In this

case, the position of these flanges with respect to the locating lips is fixed.

If the upper and lower half bearings are of the same design, then generally the two flanges of one half

bearing shall have the same thickness within the tolerance range fixed in Table 2. In that case, the flange

thicknesses result from the bearing width and the distance between flanges. Nevertheless, another

tolerance can be accepted after agreement between the user and the manufacturer (see Clause 7).

© ISO 2021 – All rights reserved 5
---------------------- Page: 9 ----------------------
ISO/DIS 3548-1:2021(E)
5.4 Free spread

Free spread is influenced by factors such as the lining material, its thickness and its physical properties,

by the bearing backing material and its properties, and by the operating temperature of the assembly.

Since these features are not specified in this documents, it is not possible to specify free spread. Free

spread shall in all circumstances be positive. After operation in the combustion engine at normal

conditions, a sufficient amount of free spread remains in the bearing to enable it to be refitted. The

actual amount of free spread shall be the subject of agreement between the manufacturer and user.

Half bearings for reciprocating machinery normally have a free spread of 0,2 mm up to 3 mm. For very

large, thin-walled half bearings, the free spread may be greater but it shall not be such that the half

bearing cannot be fitted into the housing.

Table 2 — Dimensions, tolerances and limit deviations for half bearings with and without flange

Surface rough-
a ness
Tolerance or limit deviation for
Dis-
Flange
Flange tance Hous- Bear-
Housing Wall outside Crush Sliding
Wall thickness thick- Half bearing width be- ing ing
diameter thickness diame- height surface
ness tween width back
ter
flanges
d s s s B B D B b h Ra Ra
...