144 Questions
What is the primary location of wear in a bearing?
During stopping and starting periods
What is the purpose of the oil film in a shaft bearing?
To separate the shaft from the bearing surface
What is the main advantage of using white-metal alloy in sleeve bearings?
It is soft and can conform to load conditions
What is the purpose of the oil ring in a ring-oiled bearing?
To pick up oil from the reservoir and drag it up through the bearing slot
Why are grooves in the pressure area of a bearing considered harmful?
They disrupt the oil film and reduce the size of the pressure area
What is the primary function of the feeding device in a sleeve bearing?
To supply oil to the bearing at regular intervals
What happens to the oil film as the shaft speed increases?
It becomes thicker due to the increased pumping action of the shaft
What is the purpose of chamfering or rounding corners in bearings?
To prevent scraping of the oil from the shaft
What is the main advantage of using a continuous oil supply in a bearing?
It ensures a smooth and even distribution of lubricant
What happens to the shaft as it begins to rotate in a bearing?
It rolls up the side of the bearing
What is the primary purpose of grooves in bearings?
To distribute lubricant along the shaft
Where should the lubricant application point be located in a bearing?
In a portion of the bearing that is not under pressure
What is a common sign of a failing bearing?
A rise in operating temperature
What is the purpose of water cooling in bearings?
To prevent excessive heat from developing in the bearing
How can emergency cooling of a hot sleeve bearing be achieved?
By increasing the supply of oil
What happens when water is applied directly to a hot bearing?
The bearing cap may suddenly shrink or distort
What type of force is exerted on a bearing due to the weight of the shaft?
Radial force
What is the purpose of chamfering or rounding off sharp edges in bearings?
To prevent scraping of the lubricant from the shaft
Why is it important to monitor the temperature of large bearings in critical machinery?
To prevent overheating of the bearing
What is the purpose of an auxiliary groove in a bearing?
To improve distribution of the lubricant
What is the primary cause of radial forces on bearings?
Weight of the shaft
What is the term used to describe forces parallel to the axis of the shaft?
Thrust force
What type of bearing is designed to handle axial thrust?
Thrust bearing
What is the purpose of a thrust bearing?
To prevent the shaft from moving in an axial direction
What type of lubrication is used in a collar thrust bearing?
Boundary lubrication
What type of bearing does not permit metal-to-metal contact and establishes oil wedges to carry the entire load?
Tilting pad bearing
What is the primary advantage of antifriction bearings over other types of bearings?
They have lower friction force
What is the purpose of the separator in an antifriction bearing?
To prevent the rolling elements from coming into contact with each other
What type of antifriction bearing has tapered rolling elements?
Tapered roller bearing
What is the term used to describe the bearing surfaces in a tilting pad thrust bearing?
Pads
What is the maximum amount of grease that should be added to an antifriction bearing after cleaning?
One-third full
What is the primary cause of antifriction bearing failure, even with proper maintenance and lubrication?
Metal fatigue
What is the effect of a hard mass forming within the bearing due to poor lubricant quality?
The bearing will wear excessively
What is the result of pressing a bearing onto a shaft with uneven force application?
The bearing race will crack or split
What is the maximum operating temperature that antifriction bearings can generally withstand?
120°C
What is the result of misalignment of a shaft in an antifriction bearing?
Uneven loading of the bearing
What is the main purpose of lubrication in antifriction bearings?
To protect the surfaces of the balls, rollers, and raceways from corrosion
Why is oil preferred for lubricating antifriction bearings in high-speed applications?
Because it produces less heat due to churning or displacing the lubricant
What is a potential problem with overfilling a bearing with grease?
The bearing may overheat and experience loss of lubricant
What is the purpose of the seals in an antifriction bearing?
To prevent the entrance of dirt or other impurities into the bearing housing
Why is grease preferred for lubricating antifriction bearings in applications where speeds are moderate and temperatures are not extreme?
Because it is less likely to be flung out or leak from the bearings
What is a factor that determines the type of grease to use in an antifriction bearing?
The shaft speed and exposure to moisture
What is a consequence of mixing different types of grease in an antifriction bearing?
The bearing will experience reduced lubrication effectiveness
Why is it important to know how much grease to add to an antifriction bearing?
To prevent overfilling and premature bearing failure
What is the purpose of the lubricating film in plain or shell bearings?
To separate the surfaces and reduce friction
Why is steam cylinder oil sometimes necessary for lubricating antifriction bearings?
Because it is necessary for high operating temperatures
What is a factor that determines how often bearings need to be lubricated?
Operating environment
Why is it important to warm up equipment before adding grease?
To distribute the grease throughout the bearing
What is the purpose of removing the drain plug before adding new grease?
To purge old grease from the bearing
What is the benefit of using an automatic lubricator?
To ensure worker safety and correct lubrication
How often does an oil-lubricated bearing typically need to be cleaned?
Annually
What is the first step in cleaning a bearing without dismantling it?
Remove dirt from the outside of the bearing
What should be done after adding new grease to a bearing?
Allow the machine to continue running
What happens to excess grease after adding new grease to a bearing?
It is expelled through the open drain plug
What should be done to the end of the grease gun before attaching it to the fitting?
Wipe it clean with a rag
What is the purpose of a single point automatic lubricator?
To supply lubricant to a single point at a set time
What is the recommended method to remove a bearing from a shaft?
Using a bearing puller
What should be done to the bearing after it has been removed from the shaft?
Soak it in solvent for 12 to 16 hours
What is the purpose of dipping the bearing in rust preventer and wrapping it in greaseproof paper?
To store the bearing
Why should the shaft or housing be absolutely clean before installing a bearing?
To ensure the bearing can be pressed into place without scoring or scratching
What is the ideal temperature for expanding a bearing to be installed on a shaft?
Between 80 and 100°C
What should be done to the bearing after it has been heated to the ideal temperature?
Slide it onto the shaft quickly
What should be checked for after the bearing has been cleaned and lubricated?
All of the above
Why should special heat resistant gloves be used when installing a bearing?
To prevent contamination of the bearing
What is the purpose of the temperature sensor in the induction heater?
To ensure the bearing is at the set temperature
What should be avoided when dismantling a bearing?
Hammering directly on the inner or outer race
What is the primary characteristic of boundary lubrication?
A microscopic film of lubricant separates the surfaces
What type of lubrication is also known as flood lubrication?
Fluid film lubrication
What is the critical factor in boundary lubrication at slow speeds and heavy loads?
The "oiliness" or film strength of the lubricant
Under what conditions should solid lubricants be used?
Under special conditions
What is necessary for fluid film lubrication to occur?
The bearing clearance space is completely filled with oil and the moving surface is in continual motion
What is the result of a rapidly revolving shaft in a turbine or engine main bearing?
The shaft floats on a film of oil
What is the primary factor that determines the type of lubrication used in a bearing?
Load and speed
What is the result of metal-to-metal contact between the surfaces in a bearing?
Increased friction
What is the minimum condition required for fluid film lubrication to occur?
The bearing clearance space is completely filled with oil
What is the purpose of the lubricant film in boundary lubrication?
To reduce friction by wetting the surfaces
What is the characteristic of grease that makes it suitable for use in slow speed and heavy load applications?
Greater wetting ability than conventional oil
What is the condition required for the shaft to float on a film of oil in fluid film lubrication?
The shaft is rotating above a certain minimum speed
What is the primary factor that determines the effectiveness of fluid film lubrication in a shaft bearing?
Pumping action of the rotating shaft
Why is the white-metal alloy used in sleeve bearings?
It is highly corrosion-resistant and can conform to load conditions
What is the purpose of the oil ring in a ring-oiled bearing?
To pick up oil from the reservoir and drag it up through the bearing slot
What happens to the oil film as the shaft speed decreases?
It becomes thinner and less effective
What is the purpose of grooves in the non-pressure area of a bearing?
To distribute the lubricant evenly ahead of the pressure area
What is the primary advantage of using a continuous oil supply in a bearing?
It ensures a consistent and reliable supply of lubricant
What is the result of having sharp corners at the joints of a bearing?
It tends to scrape the oil from the shaft
What is the primary characteristic of the pumping action of the rotating shaft in a bearing?
It separates the shaft from the bearing surface
What is the primary purpose of the bearing clearance space in a shaft bearing?
To facilitate the flow of lubricant to the pressure area
What is the primary cause of wear in a bearing?
Stopping and starting periods
What is the primary function of tilting pad bearings in industrial steam turbines?
To prevent metal-to-metal contact and establish oil wedges
Why are axial thrust bearings designed to handle forces parallel to the axis of the shaft?
To prevent the shaft from moving in an axial direction
What is the main characteristic of radial forces acting on bearings?
They are forces perpendicular to the axis of the shaft
What is the purpose of the separator in antifriction bearings?
To prevent the rolling elements from coming into contact with each other
What type of bearing is designed to handle radial loads?
Radial bearings
What is the main purpose of chamfering or rounding off sharp edges in bearings?
To prevent scraping of the lubricant from the shaft
What is the primary cause of radial forces on bearings?
The weight of the shaft
What is the result of sliding friction in antifriction bearings?
The friction force is decreased
What is the purpose of locating the lubricant application point in a portion of the bearing not under pressure?
To improve lubricant distribution
What is the primary advantage of antifriction bearings over other types of bearings?
They reduce friction force
What is the term used to describe forces perpendicular to the axis of the shaft?
Radial forces
What is the consequence of water being applied directly to a hot bearing?
The bearing cap may shrink or distort, reducing the running clearance
What is the primary function of the collar thrust bearing?
To prevent the shaft from moving in an axial direction
What is the purpose of an auxiliary groove in a bearing?
To improve lubricant distribution
What is the primary cause of shaft seizure in a bearing?
Reduced clearance due to bearing cap distortion
What is the characteristic of the bearing material in collar thrust bearings?
It is cast-in in the locations where the thrust collars intersect
What is the purpose of monitoring the temperature of large bearings in critical machinery?
To detect potential bearing failures and take corrective action
What is the primary advantage of using water-cooled bearings?
Reduced operating temperature
What is the consequence of improper bearing design?
Premature bearing failure
What is the primary factor in determining the location of the lubricant application point in a bearing?
The pressure area in the bearing
What is the primary purpose of lubrication in antifriction bearings?
To reduce the small amount of sliding friction present in the bearings
What is the consequence of overfilling a bearing with grease?
The bearing will overheat and the lubricant will leak away
Why is grease preferred in applications where speeds are moderate and temperatures are not extreme?
Because it is less likely to be flung out or leak from the bearings
What is the purpose of the seals in an antifriction bearing?
To prevent foreign matter from entering the bearing housing
What is the primary factor that determines the type of lubrication used in a bearing?
Operating conditions
What is the result of mixing different types of grease in an antifriction bearing?
Unpredictable bearing performance and potential failure
What is the primary purpose of lubrication in plain or shell bearings?
To separate the surfaces by means of a lubricating film
Why is oil preferred in high-speed applications?
Because it produces less heat due to churning or displacing
What is the benefit of using a continuous oil supply in a bearing?
It reduces the risk of overheating
What is the purpose of the bearing seals in preventing corrosion?
To prevent corrosion of the bearing components
What is the primary reason why a lubricant should not form a hard mass within the bearing?
It will prevent the rollers or balls from moving freely and cause wear
What is the term for the indentations that can occur in the race surfaces of a stationary bearing due to vibration?
False Brinelling
What is the maximum operating temperature that antifriction bearings can generally withstand?
120°C
What is the consequence of improper fitting of a bearing onto a shaft?
It will cause cracking or splitting of the bearing race
What is the purpose of removing the end covers when cleaning an oil-lubricated bearing?
To flush out old lubricant and sludge
What is the recommended maximum amount of grease to add to an antifriction bearing after cleaning?
One-third full
What is the result of not allowing excess grease to be expelled through the open drain plug after adding new grease?
The bearing will become over-pressurized
What is the primary cause of premature bearing failure due to misalignment?
Uneven loading of the bearing
Why is it important to warm up equipment before adding grease?
To distribute the grease throughout the bearing
What is the purpose of using a single point automatic lubricator?
To ensure the correct amount of lubricant is applied at the correct time
What is the consequence of not cleaning the bearing properly before re-lubricating?
The bearing will be damaged by contaminants
What is the purpose of squirting some grease from the end of the gun to clear it of debris?
To prevent contaminants from entering the bearing
What is the result of not allowing the machine to run after adding new grease?
The excess grease will not be expelled
What is the purpose of using a multi-point automatic lubricator?
To lubricate multiple bearings at once
What is the consequence of using a grease gun that is not properly cleaned and maintained?
The bearing will be damaged by contaminants
What is the purpose of using a web-based calculator to determine the re-greasing interval?
To ensure the correct amount of grease is applied at the correct time
What is the primary purpose of soaking the bearing in a clean solvent after it has been removed from the shaft?
To remove any remaining lubricant from the bearing
What should be done to the bearing after it has been heated to the ideal temperature for installation?
It should be quickly slid onto the shaft and seated firmly
What is the purpose of using a bearing puller to remove the bearing from the shaft?
To prevent damage to the bearing during removal
What is the result of not properly cleaning the shaft or housing before installing a bearing?
The bearing may score or scratch the shaft or housing
What should be done to the bearing after it has been cleaned and inspected?
It should be dipped in a rust preventer and wrapped in greaseproof paper
What is the purpose of using clean heat-resistant gloves when handling bearings during installation?
To prevent contamination of the bearing
What is the ideal temperature range for expanding a bearing to be installed on a shaft?
Between 80°C and 100°C
What is the purpose of rotating the bearing by hand while submerged in a solvent?
To remove any remaining lubricant from the bearing
What should be done to the bearing if it is found to be in satisfactory condition after inspection?
It should be dipped in a rust preventer and wrapped in greaseproof paper
What is the result of uneven force application when removing a bearing from a shaft?
The bearing may be damaged during removal
Learn about the two main categories of lubrication: boundary lubrication and fluid film lubrication. Understand the characteristics of each type and how they affect metal-to-metal contact and friction.
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