ISO 12132 pdf download.Plain bearings — Quality assurance of thin-walled half bearings — Design FMEA
1 Scope
This International Standard provides guidelines for the preparation of a Design FMEA for thin-walled half bearings used in internal combustion engines (the Process FMEA should be the responsibility of the supplier). It lists the common potential failure mode(s), potential effect(s) and potential cause(s) of failure. The numerical evaluation of risks in terms of occurence, 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 International Standard. General guidance on statistical assessment can be obtained from the references.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 71 46:1 993, Plain bearings — Terms, characteristics and causes of damage and changes in appearance. IEC 6081 2:1 985, Analysis techniques for system reliability — Procedure for failure mode and effects analysis (FMEA).
3 Terms and definitions
For the purposes of this International Standard the terms and definitions in IEC 6081 2 and the following apply. 3.1 FMEA Failure Mode and Effects Analysis is a method of reliability analysis intended to identify failures which have significant consequences affecting the system performance in the application considered 3.2 Design FMEA FMEA carried out by designers when developing the product 3.3 failure mode effect by which a failure is observed in the bearing 3.4 failure effect consequence of a failure mode on engine 3.5 failure cause deficiency or defect which causes a failure mode
4 Common potential failure modes, effects and causes for half bearing shells
The connecting rod and main half bearing shells of an internal combustion engine are only one part of an integrated system involving the lubricating oil, the lubrication system, the crankshaft, the engine block, the connecting rods and the half bearing shells themselves. Even the cylinder head material, bolt tightening and cylinder head gasket material have been known to influence bearing performance. Hence any consideration of internal combustion engine bearing design shall include all elements of the system not just the half bearing shells. Table 1 gives a list of common potential bearing failure modes and the effects of bearing failure together with possible causes of failure. It is rare for failures to be encountered uniquely but rather they are found in combination such that the actual initial failure mode, and hence the causes, may be difficult to determine. Failure modes of the other bearing system components are not included.