Anti Friction Bearings Flashcards
Three advantages of anti friction bearings are: (3)
- Versatility
- Low friction
- Can be packed to avoid frequent lubrication
The basic parts of an anti friction bearing are: (3)
- Two hardened steel rings (races)
- Hardened balls or rollers (rolling elements)
- separator
If there is no inner ring, the bearings fit directly on the:
Hardened shaft
Bearings may have other parts, such as a snap ring to set:
axial location
Rolling elements are classified into these 3 basic styles: (3)
- Ball
- Roller
- Needle
Roller bearings can be sub-divided into these 3 styles: (3)
- Cylindrical
- Tapered
- Spherical
Ball bearings can be used as a guide for axial shaft measurement using:
recirculating ball bushings
Many bearings use shields and seals to prevent:
Unwanted material from entering the housing
Regarding seals, you would use this type of bearing when lubricant is expected to work through the bearing from one side to the other
Open bearing
Regarding seals, you would use this type of bearing when you want solids kept out but not fluids
Shielded bearing
Regarding seals, you would use this type of bearing when you want both solids and fluids kept out
sealed bearing
Regarding seals, you would use this type of bearing when conditions are very dirty and abrasive
Shielded and sealed bearing
Ball bearings have a low to ____ load capacity
medium
roller bearings usually have a low to ____ load capacity
high
What are the three types of loads that can be applied to anti friction bearings? (3)
- Radial load
- Thrust (axial) load
- Combination radial thrust load (aka angular load)
Ball bearings are generally suited to high speed applications, up to ______ RPM
40, 000 RPM
Roller bearings are generally suited to lower speed applications, up to _____ RPM
20, 000 RPM
Normal range is 2000-20 000 RPM
As the load capacity of a bearing increases, the bore stays the same, but:
The outer diameter increases and the width and thickness of the rings increases
Regarding bearing service weight, 00 refers to:
Ultra light
Regarding bearing service weight, 100 refers to:
Extra light
Regarding bearing service weight, 200 refers to:
Light
Regarding bearing service weight, 300 refers to:
Medium
Regarding bearing service weight, 400 refers to:
Heavy duty
Roller bearings may have either a _____ or _____ bore
straight or tapered
The bearing bore size is indicated by the _______ digits of the bearing number
last two
From 20mm to 480mm, the bearing bore diameter is is found by multiplying the last two digits of the bearing number by:
5
Above 480mm, the bearing bore diameter is
directly included in the bearing number
a non separable bearing is one that:
cannot be separated easily
a separable bearing is one that:
can easily be taken apart
non aligning bearings are used in machines where:
bearings are held in alignment by the bores in the housing
self aligning bearings may be internal or external. In an internal self aligning bearing, the inside of the outer ring is:
concave
self aligning bearings may be internal or external. In an external self aligning bearing, the outside of the outer ring is:
convex
Most bearing codes give 3 pieces of information: (3)
- Type of rolling element
- Service weight
- Diameter of bore in mm
in most cases, the orientation of a bearing won’t matter, but it’s good practice to face the bearing code numbers towards the end of the shaft because:
It’s easier and quicker to identify the bearing
On a bearing code, the letter K identifies:
A tapered bore, 1:12 taper
Initial clearance is the:
Clearance in a bearing before it is installed on the shaft
Installed clearance is the clearance left in the bearing after installing it, or:
Or the clearance left in a taper bore bearing that has been forced up the taper
Running clearance is the:
Clearance left in a bearing when the machine is at operating temperature and has lubricant supplied
Bearings may have one of two fits: (2)
- Push fit
- Interference fit
Be careful when using an emery cloth to improve the shaft surface, be careful to:
Not remove interference deliberately machined in the shaft
When installing a bearing, after checking a shaft, wipe it clean and coat it with a light oil. With a press fit, you may need to use a:
Anti seize compound
Push fit means:
Bearing is installed by hand without mechanical aids
Used when the bearing is held in place by mechanical aids, such as snap rings
___ is the very slow rotation of a push fit bearing race. One rotation of the ring is equal to several million revolutions of the rest of the bearing.
Creep
Creep changes the contact area on a raceway and:
Extends the life of the bearing
The amount of interference in the shaft and bearing ring is exactly equal to the______ in the bearings after installation
Clearance reduction
To achieve interference fits, bearings can be installed using: (2)
- Press or shrink fits
- Tapered adapter sleeve
In regards to bearing fits, the usual bearing installation has:
One ring interference fit, one ring push fit