ISO 7146‑2 is an international standard that discuses plain bearings.
ISO 7146‑2 is the second part of the series that defines, describes and classifies the characteristics of damage occurring in service in hydrodynamically lubricated metallic plain bearings due to cavitation erosion, together with possible countermeasures. It assists in understanding the various characteristic forms of damage which can occur.
Consideration is restricted to damage which has a well-defined appearance and which can be attributed to particular causes with a high degree of certainty. Various appearances are illustrated with photographs and diagrams.
ISO 7146‑2 on metallic hydrodynamic bearings is applicable to:
In practice, damage to a bearing can often be the result of several mechanisms operating simultaneously. The damage can result from improper assembly or maintenance or from faulty manufacture of the bearing, its housing, or the counter face against which it operates. In some instances, damage can be caused by a design compromise made in the interests of the economy or from unforeseen operating conditions. It is the complex combination of design, manufacture, assembly, operation, maintenance, and possible reconditioning that often causes difficulty in establishing the primary cause of damage.
In the event of extensive damage or destruction of the bearing, the evidence is likely to be lost, in which case it is impossible to identify how the damage came about.
In all cases, knowledge of the actual operating conditions of the assembly and the maintenance history is of the utmost importance.
The classification of bearing damage established in ISO 7146‑2 is based primarily upon the features visible on the running surfaces and elsewhere, and consideration of each aspect is needed for reliable determination of the cause of bearing damage.
ISO 7146‑2 gives limits or reduces the effects of cavitation erosion to promote streamlined flow, modify the bearing groove by integrating edges or curves of grooves. It assists in understanding the various characteristic forms of damage which can occur.
ISO 7146‑2:2019 supersedes ISO 7146‑2:2008, which is withdrawn. The change compared to the previous edition is:
ISO 7146-2