Did You Know? Magnetic Bearings
Some very high-speed devices, like advanced flywheel energy storage
systems, use magnet bearings. These bearings allow the flywheel to
float on a magnetic field created by the bearing.
Some of the flywheels run at speeds in excess of 50,000 revolutions
per minute (rpm). Normal bearings with rollers or balls would melt
down or explode at these speeds. The magnetic bearing has no moving
parts, so it can handle these incredible speeds. |
Deep groove ball bearings are capable of operating at high
speeds and are widely used radial bearings. These non-separable bearings
are available in a wide variety of seal, shield and snap-ring
arrangements. It requires little attention or maintenance in service.
Physical Characteristics
- Deep groove ball bearings have deep uninterrupted raceways. This
allows them to carry axial loads in both directions at reasonably
high speeds.
- The bearing ring grooves are circular arcs made slightly larger
than the radius of the ball.
- The balls make point contact with the raceways (elliptical
contact when loaded).
- The inner ring shoulders are of equal height (as the outer ring
shoulders).
Advantages Of Deep Groove Ball Bearings
- Can sustain radial, axial, or composite loads.
- Can provide both high-running accuracy and high-speed operation.
- Can take the place of high speed angular contact ball bearings.
- Simple design.
- Maintenance free.
- Longer service life.
Application Of Deep Groove Ball Bearings
Deep groove ball bearings are widely used, when
- axial loads from two directions have to be transmitted, and
existing space does not allow installation of matched spindle
bearings.
- best possible guidance of rotating parts is required and speed is
less important.
Buying Tips Selecting Deep Groove
Ball Bearings
Before selecting a deep groove ball bearing you should take note of
the followings:
- Material - Chrome steel, High temperature steel, ball
material
- Maintenance requirements bearing applications
- Service life
- Bearing clearance
- Sealing efficiency
- Contamination exclusion and grease retention
- Low-friction seals for energy saving
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Types Of Deep Groove Ball Bearings
| Deep
Groove ball bearings with an outside diameter less than 9
mm are known as Miniature ball bearings. Deep Groove ball
bearings with an outside diameter ~ 9 mm and a bore
diameter < 10 mm are known as Extra-small ball bearings. Deep
groove ball bearings with seals or shields are standardized. They
contain proper amount of grease in advance. |
- Small shielded - The smaller shielded bearings
have a sheet steel shield forming a long sealing gap. These bearings
are preferred for application where the inner ring rotates. The
rotation of outer ring may cause spilling of grease.
- Large shielded - The larger shielded bearings
do not have a cylindrical section in the shield bore. These bearings
are preferred for application where the inner ring rotates. The
rotation of outer ring may cause spilling of grease.
- Low friction seal - In the ball bearings with a
low friction seal, the lip of the seal forms a narrow gap with the
land of the inner ring making it non-rubbing type. These seals allow
same quality as in shields with a better sealing. They are made of
oil and synthetic rubber with a sheet steel reinforcement. Operating
temperature is -40° C to 120° C.
- Sealed ball bearings - In the sealed ball
bearings the sealing lips seal against the recesses of the inner
ring and the outer diameter of the seal form the outer diameter of
the outer ring. They are made of oil and synthetic rubber with a
sheet steel reinforcement. Operating temperature is -40° C to
120° C. At higher speeds the grease may leak out.
Deep Groove Ball Bearings Specifications & Standards
- Dimensions - The dimensions are as per the ISO
recommendations.
- Alignment - They have limited ability to adjust
to alignment problems. There is a permissible level of angular
misalignment that will not produce additional stress. It depends on
the radial internal clearance, bearing size, internal design and
forces acting.
- Tolerance - They are usually meant for normal
tolerance but can be enhanced.
- Internal Clearance - The normal radial internal
clearance is taken as standard but there may be certain variations.
Values confirm to ISO recommendations.
Click
Here to view Radial internal clearance of deep groove ball
bearings
- Cages - There are standard cages but some may
have pressed steel cage, glass fiber reinforced, or machined brass
cages.
- Minimum Load - For satisfactory operation, the
bearings must be subjected to the minimum load that is calculated
by:
Equivalent Dynamic Bearing Load for Bearings with filling
slots
P = Fr + Fa
Provided Fa / Fr <= 0, 6 and P <
0, 5 Co.
Equivalent Static Bearing Load for Bearings with filling
slots
P0 = Fr + 0, 5 Fa
Provided Fa / Fr < 0, 6
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