Plant & Works Engineering
What is the main cause of bearing failure?
Published:  06 May, 2015

The answer to this month’s trouble shooter is provided by SKF.

Bearings are one of the most important components in machinery. When they fail, costly machine downtime follows. Bearings can fail for a number of major reasons, some of which are more common than others.

The greatest threat to the operating life and performance of a bearing is the ingress of foreign particles. These can include dirt, dust and water, and cause damage in the form of indentations, wear, corrosion and flaking.

The majority of bearing failures are the result of either operational or pre-operational damage. Operational damage occurs during the bearing service period and for two main reasons. The first reason is ineffective lubrication. This causes abrasive and adhesive wear and can be caused by insufficient and excessive lubrication, plus contamination of the lubricant. The second reason is ineffective sealing, which allows foreign particles to cause abrasive wear and moisture corrosion to greatly reduce the efficiency of the bearing.

Pre-operational damage however, occurs prior to or during bearing installation. The main reasons for this include: the use of an incorrectly fitted shaft or housing, causing bearing damage in the form of cracked rings and fretting corrosion; and the use of defective shaft or housing seats, which are deformed under load and cause fretting corrosion.

There are however, a wide range of other reasons why bearing life is reduced, such as static vibration, operational misalignment, overloading and the passage of an excessive electric current through the bearing.

By correctly specifying and installing bearings to meet the demands of an application, the many potential causes of failure can be averted and costly consequences be minimised.