Bearings Flashcards
Why do we use bearings in machines?
Allows rotation while supporting the shaft
What effect does friction have on movement?
Creates resistance to motion
How could you check clearance on a plain split bearing?
Use a dial indicator or last word indicator on the end of the shaft
What is the perfect tool to use when taking a worn bearing off a shaft?
A bearing puller
What is typical cause of Spalling?
 Fatigue
What should the oil level be on the anti-friction bearing running in an oil bath?
The oil should be third to halfway up the lowest rolling element
When installing a bearing on a shaft, what is a common method used to make the process easier?
Call the shop and properly heat the bearing
What is the best lubricant to flush away contaminants
Oil
What is the highest temperature that a bearing shock seed for the longest duration?
120° to 250 Fahrenheit
What is the typical cause of false brinelling
Vibration
What does a high-pitched scream indicate about the bearing
The clearance is too small
What must you ensure when electric welding near bearing?
Current never flows through the bearing
Which bearing may have a straight tapered or spherical race
Roller bearing
What is meant by built-in contamination
Dirt that is in induced into a machine during assembly
Which way do we tighten an electronic, locking collar bearing
Same as rotation
What is the best way to select the correct bearing?
Use the parts list provided by manufacturer
What is the purpose of seals on a sealed ball be
Keep lube in and contaminations out
What type of bearing would you use for heavy axial load
Thrust bearing
Why do we have crush and spread on steel shell bearing inserts?
To ensure tight ceiling on the bore
What temperature does Babbitt melt at?
288° C, or less
What does a loud hollow noise indicate?
Too much clearance
What does a high pitch indicate?
Clearance is too small
What does a growling noise indicate?
Surfaces of the rollers and raceways are deteriorating
What is brinelling?
Its impact denting
What will the temperature rise to when freshly installed/lubed?
About 15° above normal temp
How much percent of vibration does misalignment account for?
40%
What happens to the clearance of the bearing as it wears?
Becomes larger
4 Benefits of keeping machine clean
Allows better visual inspection
Better heat dispatch
Reduces chances of contamination entering bearing
Protects the integrity of the machine
What does rs stand for?
Rubbing seal
What is the main disadvantage of non-contact seals?
Don’t provide a positive sealand cannot retain oil, only grease
What is axial load?
Side to side
What is radial load?
Up and down
What is a series 6 bearing
Single row deep Groove ball bearing. Pg 33 ilm
Another word for plain linear bearings.
Slides or sliding - element bearings.
What is the angle of loaded zone on a roller thrust bearing
360°
What type of contact does a ball have with the raceway of bearing?
Point
When would solid bearings be used?
When speed and load are low , designed to be in places where the load is applied to the top part of the bearing
When would angle bearings be used?
When the load his applied parallel to, or at a slight angle to, the horizontal.
When the bearing is mounted on a vertical support.
Journal and pillow block bearings with anti-friction material liners are commonly used for ?
Low to medium speed and for light to heavy loads.
What is a mandrel ?
Dummy shaft
What is another name for interference fit?
Press fit
What are bushings?
One-piece liners and can be made from any common bearing materials
How is thrust controlled in a plain bearing?
By A shaft collar fastened on the shaft, or by a thrust washer backed by A sprocket or by any other hub
How is thrust in a shaft controlled?
By the shaft shoulder and a collar that adjust the amount of end float
What is endfloat?
The amount the shaft moves axially in a bearing
What kind of speeds and loads should the Kingsbury thrust bearing take?
High speeds and heavy loads.
What are the basic parts of anti- friction bearing?
Two hardened steel rings , the hardened balls or rollers and the separator.
What speeds are ball bearings suited for?
High-speeds (40,000 rpm)
What speeds are roller bearings applied to?
Low-speed application.
How is the speed of a bearing expressed?
Rpm or rubbing speed.
Clearance markings , C1, C2,C3,C4, C5. Which has the smallest clearance?
C1 has the smallest clearance.
What does push fit mean?
Bearing was installed by hand without mechanical aid.
What is creep in a bearing?
Is the very slow rotation of a push -fit bearing race.
Creep changes The contact area on the raceway and extends the life of the bearing
Back to back arrangements are used when the gutter ring is a blank??? Fit.
Press fit
Face to face arrangements are used when the inner ring is a blank???? Fit
Press fit
For standard - clearance , spherical roller bearings only, when No tables are available , a rule of thumb is to reduce the initial clearance by roughly blank??? Percent.
50 percent
Another rule of thumb is to convert the last two digits of the bearing number by
Ten-thousand of an inch
What bearings are design to carry axial loads?
Thrust bearings
What are two forms of lip contact seals?
Commercial seals
Felt seals
Symptoms of bearing failure
Temperature rise
increased vibration
Unusual noise
Rule of thumb - faster it spins , less blank??? It needs
Less grease
What is a #6 bearing?
Single-row , radial ball bearing
What ISO bearing code represents an angular contact bearing?
7
