Angular contact ball bearings feature the
highest rotational speed capabilities of all precision bearings.
The speeds illustrated in the SNFA catalog
indicate the limit at which bearings can operate continuously,
at a safe, constant temperature (thermal reference speed).
This temperature varies according to the type of lubricant
used. Limiting temperature for grease lubricated
bearings is lower than for oil because of greater lubricant
deterioration. Limiting speed for a grease lubrication is
consequently about 65% of the value achievable with oil.
To ensure high reliability, the temperature
limits referred to in setting SNFA bearing speeds are lower
than those commonly used for standard non-precision bearings
to ensure high reliability. Bearing limiting speeds depend on their
class, series and internal configuration.
The following are further elements that influence
bearing limit speed:
- preload, which affects operating temperature directly
- precision
- composition of the set and type of mounting: Face-to-face
arrangement (FF; TF, 3TF, TFT) has a lower speed limit.
- Contact angle
The maximum speeds indicated in the Data
Table refer to ABEC 7 precision class, oil lubrication, individual
and matched bearings. Series VEB and VEX are an exception
to this, as they refer to class ABEC 9.
The correction factors indicated below are
applied for calculating bearing speed in other variants not
listed in the table.
Precision
Contact Angle
Lubrication
| Characteristics bearing |
9 7 5 |
15¡ 25¡ |
Oil Grease |
|
Corrections costants |
1.1 1 .9 |
1
.9 |
1
.65 |
Achievement of maximum speed is
of course affected by correct assembly of the bearings in
their application.
The following must therefore be provided:
- housing and spindle components and bearing seats within
suitable tolerance limits
- proper dynamic balancing of rotating parts
- efficient lubrication.
|
GRW
Product Desc.