Anti-friction bearings Flashcards
The ____________ capacity of anti-friction bearings is dependent on the area of contact between the rolling elements and the raceway.
load capacity
True or false:
The load capacity of a bearing can be increased by adding rolling elements to the bearing.
true
What is the angularity of bearings?
misalignment;
the shaft is centred in the bearing, but positioned at an angle to the bearing axis
What happens to deep groove ball bearings when subjected to angularity?
the raceways will pinch the ball, causing overload and failure
True or false:
Cylindrical roller bearings handle misalignment better than deep groove ball bearings.
false;
the tolerate less angularity
Why is it generally accepted that the larger the anti-friction bearing, the slower the top speed?
the weight of the rolling elements;
the larger the bearing, the larger the elements, the more mass that is spun
If the nominal contact angle is 0º, and the load carries at 90º to the shaft axis and the bearing is a(n) ____________ load bearing.
radial
If the nominal contact angle is 90º, and the load is in line with shaft axis, the bearing is a(n) ______________ load bearing.
axial
If the nominal contact angle is between 0º and 90º, then the load acts at an angle to the shaft and the bearing is a(n) _______________ load bearing.
combination;
both radial and axial
What changes the angle of the loaded zone in an anti-friction bearing?
the amount of internal clearance and preload
What is the function of a raceway in a bearing?
to provide a smooth surface for the rolling elements to move on
True or false:
The rolling element shape is a major factor for the speed and load capacity of a bearing.
true
What is the angle of loaded zone on a roller thrust bearing?
360º
Which rolling element design allows for the greatest amount of shaft angularity?
spherical
What type of contact does a ball have with the raceway of a bearing?
point contact
What type of contact does a spherical or cylindrical roller have with the raceway of a bearing?
line contact
What are the 2 main classifications of anti-friction bearings?
- ball
- roller
What are the 4 variations of anti-friction roller bearings?
- cylindrical
- needle
- tapered
- spherical
What is the first digit on the ISO code for a single row deep groove ball bearing?
6
This type of roller bearing is a general purpose bearing and is used more widely than any other type of bearing.
single row deep groove ball bearing
True or false:
Single row deep groove ball bearings are classed as a combination load bearing, since it can support moderate axial loads.
false;
they are classed as a radial load bearing
What does a Conrad bearing refer to?
A deep groove ball bearing
Conrad created the method used to load the balls into the bearing as it is being assembled
- done by compressing the outer ring enough to bulge enough to allow the balls to be loaded
** ball bearings only
What is the first digit of the ISO bearing code of a maximum capacity deep groove ball bearing
6
- usually omitted
What physical feature can be used to identify a deep groove ball bearing is a maximum capacity bearing?
the loading slots machined into the inner and outer raceways
What is the main benefit of a maximum capacity deep groove ball bearing when compared to a normal deep groove ball bearing?
high radial load capacity
What are the 2 main limitations of a maximum capacity deep groove ball bearing when compared to a normal deep groove ball bearing?
- less axial load capacity
- more sensitive to misalignment
What is the first digit on the ISO code of a double row deep groove ball bearing?
4
What is the main design advantage of a double row deep groove ball bearing when compared to a normal deep groove ball bearing?
higher radial load without increasing the radial dimension
What is the first digit on the ISO code of a double row internally self-aligning ball bearing?
1
What is the first digit on the ISO code for an externally self-aligning ball bearing?
none;
these are usually sized in inch series
This type of ball bearing is designed to accommodate angular misalignment in mounting.
externally self-aligning ball bearings
- think pillow block
What is the first digit on the ISO code for a single row angular contact ball bearing?
7
This type of ball bearing can support substantial thrust loads in a single direction and must operate with an axial load component (ideally, a combination).
single row angular contact ball bearing
With a single row angular contact ball bearing, the thrust load must be against the ___________ shoulder on both races.
high
What is the first digit on the ISO bearing code for a double row angular contact ball bearing?
0
What kinds of loads can a double row angular contact ball bearing accommodate?
heavy radial and axial loads
Double row angular contact ball bearings cannot tolerate any misalignment. Why is this?
the misalignment alters the load distribution between the two rings
What types of loads can a single row angular contact ball bearing not operate with?
purely radial loads
What is the first digit on the ISO bearing code for a four-point angular contact ball bearing?
QJ
True or false:
A four-point angular contact ball bearing is considered a high capacity bearing.
true
- the split allows for additional balls to be placed in the raceway
What types of loads can a four-point angular contact ball bearing accommodate?
axial or combination;
- it cannot handle a purely radial load because of the split along the inner race
What type of load can a four-point angular contact ball bearing not handle?
purely radial
True or false:
Four-point angular contact ball bearings can handle reversing thrust loads.
true
What is the first digit on the ISO bearing code for a ball thrust bearing?
5
What is the speed limit of a ball thrust bearing when compared to a radial load bearing of the same size?
about half the speed
What are the 4 common shapes of roller bearings?
- cylindrical
- needle
- tapered
- spherical
What does it mean when a bearing has the ability to displace?
the rolling elements can move axially in the bearing raceway
What is the first digit on the ISO bearing code for single row cylindrical roller radial load bearings?
N
What is the first digit on the ISO bearing code for a cylindrical roller thrust bearing?
8
What can happen if cylindrical thrust roller bearings travel too quickly?
the inside and outside diameter of the rollers travel at different speeds, causing skidding on one part of the roller if they travel too fast
What are 3 common types of needle bearings?
- no cage or inner ring
- drawn steel cup and no inner ring
- machined inner and outer rings
In bearings, what is the relationship between friction and speed?
friction up = speed down
- the more friction in a bearing, the slower the top speed
This type of needle bearing is restricted to slow speeds or oscillating motions since the rollers rub against each other.
no cage or inner ring needle bearing
What is the inner ring of an anti-friction bearing?
The ring that sits on a shaft when mounted
With an anti-friction bearing, which ring would sit in a housing?
The outer ring
With an anti-friction bearing, the surface on which the rolling members roll on is called the:
Raceway
This component of an anti-friction bearing supports the load and ideally should roll (not slide, skid, or drag).
The rolling elements
What component of an anti-friction bearing separates the rolling elements from each other?
The cage
What are the 3 functions of the cage in an anti-friction roller bearing?
- Prevents rolling elements from rubbing against each other
- Pushes the rolling elements through the unloaded zone
- Guide the rolling elements with minimal amount of friction
Identify the following bearing type and the first digit of its design code:
Four-point angular contact ball bearing
First digit of ISO design code: QJ
Identify the following bearing type and the first digit of its design code:
Double row internally self-aligning ball bearing
First digit of ISO design code: 1
Identify the following bearing type and the first digit of its design code:
Single direction ball thrust bearing
First digit of ISO design code: 5
Identify the following bearing type and its design code:
Single direction external self-aligning ball thrust bearing
ISO design code: 5
Which type of ball thrust bearing can correct for some misalignment?
Single direction external self-aligning ball thrust bear
Identify the following bearing type and the first digit of its design code:
Double direction ball thrust bearing
First digit of ISO design code: 5
Identify the following bearing type and the first digit of its design code:
Single row angular contact ball bearing
First digit of ISO design code: 7
Identify the following bearing type and its design code:
Single row deep groove ball bearing
ISO design code: 6
Identify the following bearing type and the first digit of its design code:
Double row deep groove ball bearing
First digit of ISO code: 4
Identify the following bearing type and its design code:
Tapered roller bearing
ISO design code: 3
- ISO code may not be reliable, as often they will be an inch series bearing
Identify the following bearing type and its design code:
CARB bearing
ISO design code: C
Identify the following bearing type and its design code:
Spherical roller bearing
ISO design code: 2
Identify the following bearing type and its design code:
Drawn steel cup and no inner ring needle bearing
ISO design code: none; manufacturer nomenclature
Identify the following bearing type and its design code:
No cage or inner ring needle bearing
ISO design code: none; manufacturer nomenclature
Identify the following bearing type and its design code:
Machined inner and outer rings needle bearing
ISO design code: none; manufacturer nomenclature
Identify the following bearing type and its design code:
Cylindrical roller bearing
ISO design code: N
Identify the following bearing type and the first digit of its design code:
Cylindrical roller thrust bearing
First digit of ISO design code: 8