SIST ISO 13778:2020

Plain bearings - Quality assurance of thin-walled half bearings - Selective assembly of bearings to achieve a narrow clearance range

ISO 13778:2017 specifies the selective assembly of bearings (in accordance with ISO 3548‑1).
The bearing diametral clearance is determined by the housing diameter, journal diameter and the wall thickness of the two half bearings. Typically, these components will have a total tolerance "stack up" of 50 µm to 60 µm. Current engine development and in particular, the desire for improved engine refinement, has provided a need to decrease the clearance range due to the tolerance "stack up". This document suggests various schemes of selective assembly to achieve such ranges.

Paliers lisses - Assurances qualité des demi-coussinets minces - Assemblage sélectif des paliers pour obtenir un jeu faible

Drsni ležaji - Zagotavljanje kakovosti tankostenih ležajnih blazinic - Selektivni izbor blazinic za ozek tolerančni razpon

General Information

• Status: Published
• Publication Date: 12-Mar-2020
• ICS: 21.100.10 - Plain bearings
• Technical Committee: ISEL - Mechanical elements
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 11-Mar-2020
• Due Date: 16-May-2020
• Completion Date: 13-Mar-2020
• Ref Project: ISO 13778:2017 - Plain bearings - Quality assurance of thin-walled half bearings - Selective assembly of bearings to achieve a narrow clearance range

Relations

• Revised: SIST ISO 13778:2002 - Plain bearings -- Quality assurance of thin-walled half bearings -- Selective assembly of bearings to achieve a narrow clearance range
• Effective Date: 04-Nov-2015

Overview

ISO 13778:2017 - "Plain bearings - Quality assurance of thin-walled half bearings - Selective assembly of bearings to achieve a narrow clearance range" - provides guidance for selectively assembling thin-walled half bearings (in accordance with ISO 3548‑1) to control and reduce bearing diametral clearance. The standard addresses the combined effect of housing diameter, journal diameter and bearing wall thickness (tolerance “stack up” typically 50–60 µm), and describes grading and matrix schemes to achieve tighter clearances required for modern engine refinement.

Key topics and requirements

• Selective assembly principles: Methods to combine graded components so the effective diametral clearance meets a narrower specified range.
• Clearance calculation: Theoretical diametral clearance C = D_H – (2·s + D_J), where D_H is housing diameter, s is half-bearing wall thickness, and D_J is journal diameter.
• Tolerance stack up: Recognition that housing, journal and bearing tolerances accumulate; typical stack-up and need to reduce range for improved NVH and performance.
• Housing swell & thermal expansion: Effects of interference fit, bolt torque and material (e.g., light alloys) on bore expansion; guidance to measure and allow for swell and thermal effects.
• Measurement & identification: Accurate metrology (micrometre-level) for housings, journals and bearing crowns; practical marking methods (colour codes, bar/dot coding, etching) and data storage for assembly.
• Grading schemes: Six example fitting schemes increasing in complexity and precision:
  • Scheme 1: No grading (standard process capability)
  • Scheme 2: Bearings graded only
  • Scheme 3: Bearings and journals/housings graded
  • Scheme 4: Unmixed bearings (matrix scheme) - narrowest range example
  • Scheme 5: Mixed bearings (matrix scheme)
  • Scheme 6: Mixed bearings (fine matrix) - micrometre-level selection
• Trade-offs: Narrower clearance ranges require tighter component tolerances, more complex logistics and inventory control; schemes may be suitable for OEM assembly but impractical for aftermarket replacement sets.

Applications

• Used primarily in internal combustion engine main and rod bearing assembly where improved refinement and reduced bearing clearance are required.
• Applicable to bearing manufacturers, engine OEMs, assembly engineers, quality and metrology teams, and powertrain development groups planning selective assembly programs.
• Helps reduce NVH, optimize oil film performance and extend bearing life by controlling clearance distributions.

Who will use this standard

• Bearing suppliers implementing grading and identification processes
• Engine manufacturers designing assembly and quality assurance procedures
• Quality engineers developing measurement and tolerance control plans
• Metrology labs specifying measurement methods for housings, journals and bearing crowns

Related standards

• ISO 3548-1 - Thin-walled half bearings: tolerances, design features and methods of test (normative reference)
• ISO 4378-1 - Terms, definitions, classification and symbols for plain bearings

Keywords: ISO 13778:2017, plain bearings, thin-walled half bearings, selective assembly, bearing clearance, bearing grading, housing swell, tolerance stack up, matrix scheme, quality assurance.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2020
Drsni ležaji - Zagotavljanje kakovosti tankostenih ležajnih blazinic - Selektivni
izbor blazinic za ozek tolerančni razpon
Plain bearings - Quality assurance of thin-walled half bearings - Selective assembly of
bearings to achieve a narrow clearance range
Paliers lisses - Assurances qualité des demi-coussinets minces - Assemblage sélectif
des paliers pour obtenir un jeu faible
Ta slovenski standard je istoveten z: ISO 13778:2017
ICS:
21.100.10 Drsni ležaji Plain bearings
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 13778
Second edition
2017-03
Plain bearings — Quality assurance of
thin-walled half bearings — Selective
assembly of bearings to achieve a
narrow clearance range
Paliers lisses — Assurances qualité des demi-coussinets minces —
Assemblage sélectif des paliers pour obtenir un jeu faible
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Housing swell and thermal expansion . 2
5 Measurement and identification . 2
5.1 Housings and journals . 2
5.2 Bearings . 2
6 Suggested schemes for fitting . 3
6.1 General . 3
6.2 Scheme 1: Standard application, without grading . 3
6.3 Scheme 2: Grading of bearings . 4
6.4 Scheme 3: Grading of bearings and journals or housings . 4
6.5 Scheme 4: Unmixed bearings (Matrix scheme) . 5
6.6 Scheme 5: Mixed bearings (Matrix scheme). 6
6.7 Scheme 6: Mixed bearings (fine matrix) . 6
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 on 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 the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 5,
Quality analysis and assurance.
This second edition cancels and replaces the first edition (ISO 13778:1999), which has been technically
revised.
iv © ISO 2017 – All rights reserved

INTERNATIONAL STANDARD ISO 13778:2017(E)
Plain bearings — Quality assurance of thin-walled half
bearings — Selective assembly of bearings to achieve a
narrow clearance range
1 Scope
This document specifies the selective assembly of bearings (in accordance with ISO 3548-1).
The bearing diametral clearance is determined by the housing diameter, journal diameter and the
wall thickness of the two half bearings. Typically, these components will have a total tolerance “stack
up” of 50 µm to 60 µm. Current engine development and in particular, the desire for improved engine
refinement, has provided a need to decrease the clearance range due to the tolerance “stack up”. This
document suggests various schemes of selective assembly to achieve such ranges.
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 3548-1, Plain bearings — Thin-walled half bearings with or without flange — Part 1: Tolerances, design
features and methods of test
ISO 4378-1, Plain bearings — Terms, definitions, classification and symbols — Part 1: Design, bearing
materials and their properties
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4378-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
theoretical bearing diametral clearance
C
difference between the housing diameter, D , less twice the half bearing wall thickness (3.3), s , and the
H 3
journal diameter (3.4), D
J
C = D – (2s + D )
H 3 J
3.2
housing diameter
D
H
diameter of the housing with no bearing fitted measured perpendicular to the split line
3.3
bearing wall thickness
s
wall thickness measured at 90° from the split line (at the “crown”)
Note 1 to entry: If two measurements are made, the larger of the two is used.
3.4
journal diameter
D
J
diameter of the finished shaft measured at a position to give maximum diameter
3.5
tolerance
range between the upper and lower limits specified on the drawing
3.6
housing swell
expansion of a housing bore caused by the interference fit of the bearings
4 Housing swell and thermal expansion
Housing swell is defined as the “expansion of a housing bore, caused by the interference fit of the
bearings”. When two half bearings are assembled into a housing and the housing is bolted up, the
assembled bore will be slightly greater than the arithmetical subtraction of the two bearing wall
thicknesses from the housing diameter as measured before the bearing is fitted. Housing swell is
generally of the order of a few micrometres. Maximum housing swell will occur with a combination
of maximum bearing overstand (nip) and minimum housing diameter. It is prudent to measure actual
housing swell by carrying out fitting tests. Actual housing deformation may also b
...

INTERNATIONAL ISO
STANDARD 13778
Second edition
2017-03
Plain bearings — Quality assurance of
thin-walled half bearings — Selective
assembly of bearings to achieve a
narrow clearance range
Paliers lisses — Assurances qualité des demi-coussinets minces —
Assemblage sélectif des paliers pour obtenir un jeu faible
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Housing swell and thermal expansion . 2
5 Measurement and identification . 2
5.1 Housings and journals . 2
5.2 Bearings . 2
6 Suggested schemes for fitting . 3
6.1 General . 3
6.2 Scheme 1: Standard application, without grading . 3
6.3 Scheme 2: Grading of bearings . 4
6.4 Scheme 3: Grading of bearings and journals or housings . 4
6.5 Scheme 4: Unmixed bearings (Matrix scheme) . 5
6.6 Scheme 5: Mixed bearings (Matrix scheme). 6
6.7 Scheme 6: Mixed bearings (fine matrix) . 6
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 on 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 the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 5,
Quality analysis and assurance.
This second edition cancels and replaces the first edition (ISO 13778:1999), which has been technically
revised.
iv © ISO 2017 – All rights reserved

INTERNATIONAL STANDARD ISO 13778:2017(E)
Plain bearings — Quality assurance of thin-walled half
bearings — Selective assembly of bearings to achieve a
narrow clearance range
1 Scope
This document specifies the selective assembly of bearings (in accordance with ISO 3548-1).
The bearing diametral clearance is determined by the housing diameter, journal diameter and the
wall thickness of the two half bearings. Typically, these components will have a total tolerance “stack
up” of 50 µm to 60 µm. Current engine development and in particular, the desire for improved engine
refinement, has provided a need to decrease the clearance range due to the tolerance “stack up”. This
document suggests various schemes of selective assembly to achieve such ranges.
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 3548-1, Plain bearings — Thin-walled half bearings with or without flange — Part 1: Tolerances, design
features and methods of test
ISO 4378-1, Plain bearings — Terms, definitions, classification and symbols — Part 1: Design, bearing
materials and their properties
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4378-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
theoretical bearing diametral clearance
C
difference between the housing diameter, D , less twice the half bearing wall thickness (3.3), s , and the
H 3
journal diameter (3.4), D
J
C = D – (2s + D )
H 3 J
3.2
housing diameter
D
H
diameter of the housing with no bearing fitted measured perpendicular to the split line
3.3
bearing wall thickness
s
wall thickness measured at 90° from the split line (at the “crown”)
Note 1 to entry: If two measurements are made, the larger of the two is used.
3.4
journal diameter
D
J
diameter of the finished shaft measured at a position to give maximum diameter
3.5
tolerance
range between the upper and lower limits specified on the drawing
3.6
housing swell
expansion of a housing bore caused by the interference fit of the bearings
4 Housing swell and thermal expansion
Housing swell is defined as the “expansion of a housing bore, caused by the interference fit of the
bearings”. When two half bearings are assembled into a housing and the housing is bolted up, the
assembled bore will be slightly greater than the arithmetical subtraction of the two bearing wall
thicknesses from the housing diameter as measured before the bearing is fitted. Housing swell is
generally of the order of a few micrometres. Maximum housing swell will occur with a combination
of maximum bearing overstand (nip) and minimum housing diameter. It is prudent to measure actual
housing swell by carrying out fitting tests. Actual housing deformation may also be affected by the
degree of control of bolt tension.
With light alloy housings, the housing swell may be larger, due not only to the lower modulus of elasticity
but also to thermal expansion.
Allowance for housing swell and thermal expansion has to be made when setting the bearing diametral
clearance.
5 Measurement and identification
5.1 Housings and journals
Specific measurement of each housing and journal may be necessary in more complex grading schemes.
While bearings will
...