3 Reasons For Premature Bearing Failure (And How To Avoid Them)

Every failed bearing tells a story - one that can help identify machinery problems, maintenance issues, bearing selection errors and other important issues. Are you interested?

In the pulp and paper industry, bearings face harsh conditions every day, and this can result in premature bearing failure. When bearings fail, quick replacement to minimize downtime is the first priority. In fact, taking the time to investigate the causes of bearing failure can actually increase uptime and decrease both maintenance time and cost.

Creep

Creep is where slipping occurs at the fitting surfaces and thereby creates a clearance at the fitting surface.

What to Look For: A shiny bearing surface, occasionally with scoring or wear.

Cause:

Insufficient interference or loose fit

Insufficient sleeve tightening

Solution:

Check the interference, and prevent rotation

Correct the sleeve tightening

Study the shaft and housing precision

Preload in the axial direction

Tighten the raceway ring side face

Apply adhesive to the fitting surface

Apply a film of lubricant to the fitting surface

Flaking

Flaking occurs when small pieces of bearing material are split off from the smooth surface of the raceway or rolling elements due to rolling fatigue, thereby creating regions having rough and coarse texture.

What to Look For: Rough, course texture on the bearing surface.

Cause:

Excessive load

Poor mounting (misalignment)

Moment load

Entry of foreign debris, water penetration

Poor lubrication, improper lubricant

Unsuitable bearing clearance

Improper precision for shaft or housing, unevenness in housing rigidity, large shaft bending

Progression from rust, corrosion pits, smearing, dents (brinelling)

Solution:

Reconfirm the bearing application and check the load conditions

Improve the mounting method

Improve the sealing mechanism, prevent rusting during non-running

Use a lubricant with a proper viscosity, improve the lubrication method

Check the precision of shaft and housing

Check the bearing internal clearance

Smearing

Smearing is surface damage that occurs from a collection of small seizures between bearing components caused by oil film rupture and/or sliding.

What to Look For: Surface roughening occurs along with melting.

Cause:

High speed and light load

Sudden acceleration/deceleration

Improper lubricant

Entry of water

Solution:

Improve the preload

Improve the bearing clearance

Use a lubricant with good oil film formation ability

Improve the lubrication method (download our Lubrication Guide for easy reference)

Improve the sealing mechanism

Bearing failure not only affects specific equipment, it can cause entire facilities to grind to a halt. Don't address the immediate problem by simply installing a new bearing; investigate the cause of bearing failure. You may be able to prolong bearing life, improve productivity and reduce maintenance costs by identifying and resolving issues around bearing selection, mounting, lubrication and application.

For more information on maximizing bearing life to increase uptime, visit http://www.thinknskuptime.com and access our online solution guide!

NSK Corporation