© ISO 2017 Plain bearings — Quality assurance of thin walled half bearings — Design FMEA Paliers lisses — Assurance qualité des demi coussinets minces — AMDE à la conception INTERNATIONAL STANDARD ISO[.]
INTERNATIONAL STANDARD ISO 12132 Second edition 2017-03 Plain bearings — Quality assurance of thin-walled half bearings — Design FMEA Paliers lisses — Assurance qualité des demi-coussinets minces — AMDE la conception Reference number ISO 12132:2017(E) © ISO 2017 ISO 12132:2017(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2017, Published in Switzerland All rights reserved Unless otherwise specified, no part o f 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 o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2017 – All rights reserved ISO : 01 7(E) Contents Page iv Introduction v Scope Normative references Terms and definitions Common potential failure modes, effects and causes for half bearing shells Bibliography Foreword © ISO 2017 – All rights reserved iii ISO 12132:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f 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 o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f 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 in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the voluntary nature o f standards, the meaning o f ISO specific terms and expressions related to formity assessment, as well as in formation about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso 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 12132:1992), which has been technically revised iv © ISO 2017 – All rights reserved ISO : 01 7(E) Introduction FMEA (Failure Mode and E ffects Analysis) is a form o f analytical method that helps to define potential defects of the designed products and to eliminate these defects at the stage of designing FMEA is based on combining the experience gained in practice in designing and operation of plain bearings with the theory o f probability FMEA increases reliability and quality o f the product in question and that o f its technology and also reduces the expenses for testing the product and for improving the technological process Systems for the implementation o f a Design FMEA are well documented elsewhere and are outside the scope o f this document These systems aid in the analysis o f complex designs, both existing and projected © ISO 2017 – All rights reserved v INTERNATIONAL STANDARD ISO 12132:2017(E) Plain bearings — Quality assurance of thin-walled half bearings — Design FMEA Scope This document gives guidelines for the preparation of a Design FMEA for thin-walled half bearings used in machinery, e.g internal combustion engines (the Process FMEA is the responsibility o f the supplier) It lists the common potential failure mode(s), potential effect(s) and potential cause(s) of failure The numerical evaluation o f risks in terms o f occurrence, severity and detection can be specific to each application, manufacturer and customer Since they have to be assessed in each case, the numerical data are not included in this document General guidance on statistical assessment can be obtained from the references Normative references The following documents are re ferred to in the text in such a way that some or all o f their content constitutes requirements o f this document For dated re ferences, only the edition cited applies For undated re ferences, the latest edition o f the re ferenced document (including any amendments) applies IEC 60812, Analysis techniques for system reliability — Procedure for failure mode and effects analysis (FMEA) Terms and definitions For the purposes o f this document, the terms and definitions given in IEC 60812 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 Failure Mode and Effects Analysis FMEA method o f reliability analysis intended to identi fy potential failures which have significant consequences a ffecting the system per formance in the application considered 3.2 Design FMEA FMEA (3.1) carried out by designers when developing the product 3.3 failure mode e ffect by which a failure is observed in the bearing 3.4 failure effect consequence of a failure mode (3.3 ) on the bearing system and equipment condition and operation 3.5 failure cause deficiency or de fect which causes a failure mode (3.3) © ISO 2017 – All rights reserved ISO : 01 7(E) Common potential failure modes, effects and causes for half bearing shells T he ne c ti ng ro d and ma i n l f b e ari ng s hel l s o f a mach i ne are on ly one p a r t o f an i ntegrate d s ys tem i nvolvi ng the lubric ati ng oi l, the lubric ation s ys tem, the c ran ks ft, the engi ne blo ck, the ne c ti ng ro d s and the l f b e a ri ng shel l s them s elve s E ven the c yl i nder he ad materi a l, b olt tighten i ng and c yl i nder he ad ga ske t materia l have b e en known to i n fluence b e ari ng p er forma nce H ence, any s ideration o f i nterna l combu s tion engi ne b e ari ng de s ign s l l i nclude a l l elements o f the s ys tem no t j u s t the h a l f bearing shells Table gives a list of common potential bearing failure modes and the effects of bearing failure together with p o s s ib le c au s e s o f found fa i lu re I t i s rare for fai lure s i n combi nation s uch that the ac tua l i niti a l to b e encou ntere d u n iquely but rather they a re fa i lu re mo de, and hence the c au s e s , may b e d i ffic u lt to de term i ne Fai lu re mo de s o f the o ther b e ari ng s ys tem comp onents a re no t i nclude d © ISO 2017 – All rights reserved ISO 12132:2017(E) Table — Potential failure modes of half bearings and their effects and causes No Potential failure mode Potential effects of failure Potential cause of failure Bearing-related System-related Fatigue Reduced bearing Insu fficient bearing Incorrect specification o f durability and/or diameter cylinder pressures firing load (see ISO 7146-1:2008, bearing seizure 6.3) Insu fficient bearing length Oil pump capacity calculation Contamination o f oil by Incorrect material Insu fficient e ffective fatigue debris selection (fatigue journal length Engine inoperative resistance) Poor journal geometry Localized overloading due (ovality, axial form, lobing) to presence and location Poor housing geometry of bearing features (holes, (ovality, lobing) grooves, etc.) Insu fficient housing dynamic Excessive bearing stiffness (circumferential, material thickness radial or axial) Excessive overlay Excessive oil temperature thickness and/or insu fficient oil cooling Unsupported bearing Bearing system areas contaminated by foreign particles or wear debris from other components Accelerated wear Reduced bearing Insu fficient bearing length Incorrect lubricant choice (Insu fficient oil film durability and/or Incorrect oil additive Insu fficient bearing thickness or debris bearing seizure specification diameter contamination) Noise Poor oil and/or oil additive Incorrect material (see ISO 7146-1:2008, Reduction of oil stability selection (wear 6.6 and 6.7.1) pressure resistance, Poor lubricant supply embeddability) (inadequate oil pressure or supply capacity, drilling Inappropriate overlay diameters too small or thickness (wear poorly positioned, etc.) resistance, embeddability) Poorly located bearing Aerated or “poor quality” oil supply (rough drillings or features (holes, grooves, sharp bends in lubrication etc.) system, poor sump ba ffling, poor oil pick up, etc.) Inadequate oil grooves Inadequate oil filtration and holes Incorrect bearing Insu fficient e ffective thickness (inadequate journal length clearance or excessive Insu fficient journal diameter clearance) Poor journal geometry Incorrect bearing (ovality, axial form, lobing) thickness geometry (taper, eccentricity, etc.) Poor journal sur face topography (finish, lay, etc.) Poor engine balance Poor housing geometry (ovality, lobing) Unsupported bearing areas Insu fficient oil temperature and/or insu fficient oil cooling © ISO 2017 – All rights reserved ISO 12132:2017(E) Table (continued) No Potential failure mode Potential effects of failure Potential cause of failure Bearing-related System-related Contamination by wear debris from other components Excessive ingested debris Infrequent oil and/or oil filter change intervals Excessive coolant contamination Excessive contamination by Excessive wear and Reduced bearing scuff (over-heating) durability and/or (see ISO 7146-1:2008, bearing seizure Clause 8) fuel and combustion products Incorrect journal diameter Incorrect bearing (clearance) thickness (inadequate clearance or excessive journal geometry clearance, poor bearing Poor (ovality, axial form, lobing) back formability with housing) Unsuitable journal sur face topography Incorrect bearing thickness geometry (taper, eccentricity, etc.) Poorly located bearing Incorrect fillet radius geometry Incorrect housing diameter features (holes, grooves, (inter ference fit) etc.) Poor housing geometry Inadequate oil grooves (ovality, axial form, lobing) and holes Insu fficient housing Inadequate clamping (bolt) load circumferential length Poor lubricant supply (inadequate interference (inadequate oil pressure or fit) supply capacity, drilling Inadequate bearing back diameters, too small or poorcontact ly positioned, etc.) Incorrect material Excessive oil drain down or selection (con formability, delayed oil supply compatibility) Aerated or “poor quality” oil Incorrect diffusion barrier supply (rough drillings or material sharp bends in lubrification Excessive differential ther- system, poor sump ba ffing, mal expansion between poor oil pick up, etc.) housing and bearing shells Insu fficient “running-in” or housing and shaft (loss Insu fficient axial clearance at o f inter ference fit) ends of bearing © ISO 2017 – All rights reserved ISO 12132:2017(E) Table (continued) No Potential failure mode Potential cause of failure Bearing-related System-related Potential effects of failure Excessive localized f f wear features (holes, grooves, crankshaft oil drilling into Reduced oil pressure etc.) (see ISO 7146-1:2008, 6.4 and Clause 8) Incorrect bearing Re duce d du rabi l ity Po o rl y lo c ate d b e a ri n g I n s u fic ient b lend i n g o j ou rn a l I ncor re c t fi l le t rad iu s th ickne s s ge ome tr y (a xi a l fo r m , e ccentr ic ity, e tc ) I nco r re c tl y s p e c i fie d i nter n a l ch a m fers (fi l le t ride) I nco r re c tl y s p e c i fie d bearing bore relief ge ome tr y I n s u ffic ient b u i ld cle a n l i ne s s Po or ho u s i ng ge ome tr y (o va l ity, a xi a l for m , lob i ng) Inadequate bearing housing cap location Po orl y lo c ate d hou s i ng locating tang (notch, lug features (holes, grooves, etc.) or nick) f ff (radial and axial) Inadequate bearing back contact bearing tang pockets in housing Poor bearing alignment (engine block alignment, connecting rod straightness or twist) Excessive off-set connecting rod loading I nco r re c tl y s p e c i fie d I n s u fic ient ho u s i n g s ti ne s s I ncor re c tl y p o s itio ne d Po or j ou r n a l ge o me tr y (o va l ity, a xi a l for m , lob i ng) Po or c n ks h a ft m a i n j o u r n a l Damage to the Reduced bearing bearing back (see ISO 7146-1:2008, bearing seizure 7.2 and 7.3) Connecting rod breakage du rab i l ity a nd/o r Inadequate circumferential length (i nter ference fit) alignment I n s u ffic ient ho u s i n g dyn a m ic stiffness (circumferential, radial or axial) Inadequate bearing back f contact clamping (bolt) load Excessive differential Incorrect housing diameter thermal expansion bef tween housing and bearing Unsupported bearing areas shells or housing and shaft I n s u fic ient ho u s i n g (i nter erence fit) ( los s o f inter ference fit) Incompatible housing material and bearing back material © ISO 2017 – All rights reserved ISO 12132:2017(E) Table (continued) No Potential failure mode Potential effects of failure Corrosion Reduced bearing and/or (see ISO 7146-1:2008, durability bearing seizure 6.7.2) Increased wear and/ or noise Potential cause of failure Bearing-related System-related Incorrect material selection (poor corrosion resistance) Incorrect lubricant choice Incorrect oil additive specification Poor oil and/or oil additive stability Excessive oil temperature and/or insu fficient oil cooling Infrequent oil change intervals Excessive coolant contamination Excessive contamination by Cavitation erosion Poor cosmetic but not (see ISO 7146-1:2008, appearance normally damaging 6.8 and ISO 7146-2) on overlay plated bearings Corrosion of substrate in extreme cases Localized fatigue failure in bimetallic bearings Reduced oil supply or pressure Subsequent scoring, indenting and embedment by removed lining material Incorrect bearing calculation Inadequate oil groove chamfers Inadequate “run-in” fuel and combustion products Incorrect lubricant choice Poor lubricant supply (inadequate oil pressure or supply capacity, drilling diameters, too small or poor- ly positioned, etc.) grooves Aerated or poor “quality” oil Excessive clearance supply (rough drillings or Incorrect groove positions sharp bends in lubrication system, poor sump ba ffling, Inadequate groove detail poor oil pick up, etc.) design Vibration Incorrect material selection © ISO 2017 – All rights reserved ISO : 01 7(E) Bibliography [1] ISO 7146-1:2008, Plain bearings — Appearance and characterization of damage to metallic hydrodynamic bearings — Part 1: General [2] ISO 7146-2, Plain bearings — Appearance and characterization ofdamage to metallic hydrodynamic bearings — Part 2: Cavitation erosion and its countermeasures © ISO 2017 – All rights reserved ISO 12132:2017(E) ICS 1 00.1 Price based on pages © ISO 2017 – All rights reserved