BEARINGS Flashcards
The bearings should be removed from the wheel to be cleaned with the recommended solvent, such as ______.
Varsol, Naptha, or Stoddard(R) solvent
· ______ —caused by rubbing of mating surfaces. The metal gets so hot it welds, and the surface metal is destroyed as the motion continues and pulls the metal apart in the direction of motion.
Galling
· _____—a chipped away portion of the hardened surface of a bearing roller or race.
Spalling
________ —caused by lack of sufficient lubrication results in a bluish tint to the metal surface. The ends of the rollers shown were overheated causing the metal to flow and deform, as well as discolor. The bearing cup raceway is usually discolored.
Overheating
______ —caused by excessive impact. It appears as indentations in the bearing cup raceways. Any static overload or severe impact can cause true brinelling that leads to vibration and premature bearing failure
Brinelling
______ —caused by vibration of the bearing while in a static state. Even with a static overload, lubricant can be forced from between the rollers and the raceway. Submicroscopic particles removed at the points of metal-to-metal contact oxidize. They work to remove more particles spreading the damage. This is also known as frictional corrosion. It can be identified by a rusty coloring of the lubricant
False Brinelling
______ —located on the bearing cup as grayish black streaks with the same spacing as the rollers and caused by water that has gotten into the bearing. It is the first stage of deeper corrosion that follows.
Staining and surface marks
· ______ —caused when water and the damage caused by water penetrates the surface treatment of the bearing element. It appears as a reddish/brown discoloration.
Etching and corrosion
· ______ —caused by fine particle contamination possibly from a bad seal or improper maintenance of bearing cleanliness. It leaves a less than smooth surface on the bearing cup.
Bruising
______ is a leading cause of bearing failure
Contamination
When an electric current passes through a bearing, proceeding from one ring to the other via the rolling elements, damage will occur. At the contact surfaces the process is similar to electric arc welding
ELECTRIC CURRENT DAMAGE
The passage of electric current frequently leads to the formation of ______ (corrugation) in bearing raceways.
Rollers are also subject to _____ , while there is only dark discoloration of balls. It can be difficult to distinguish between electric current damage and vibration damage
fluting
