• If any of these dimensions are out of spec, the journal (pulley) should be replaced. The journals at the seal position, likewise, need to be in good condition. Check for wear or damage that is preventing adequate contact or creating too much clearance for a labyrinth seal. These circumstances also require replacement of the pulley. If the journals on both ends of the pulleys pass inspection, record this information on a journal inspection chart.
• Straight bore bearings also require an interference fit to the journal. The safest and easiest method of mounting this type of bearing is to use an induction heater or, as an alternative, an oil bath heater. Make sure the oil is free of sludge and contaminants. Never heat the bearing more than 250 degrees Farenheit. Never use a torch to heat the bearing.
• Avoid pushing against the bearing case or rollers during installation.
• Make sure packaging-type seals are fully saturated with oil before fitting. Lubricate the lips of oil seals to prevent damage and make them easier to install.
• Pack the labyrinth grooves with grease and make sure they are in proper housing grooves.
• Take measurements to ensure the bearings are correctly located on the journal — this will prevent an abnormal thrust load on the bearings.
Information for this article courtesy of NSK Corp.
For more information, visit www.nskamericas.com.