Page 191 - Rollingbearings

Additional options
Cages made of other Additional options scanning electron microscope and a pat-
materials ented examination method.
In addition to the materials described previ- Coatings NoWear
ously, SKF bearings for special applications
may be itted with cages made of other engi- Coating is a well-established method to NoWear is a wear -resistant surface coating
neered polymers, light alloys or special cast upgrade materials and to provide bearings that applies a low- friction carbon coating on
iron. For additional information about alter- with additional beneits for speciic applica- the bearing inner ring raceway(s) and/or the
native cage materials, contact SKF. tion conditions. Various coating methods rolling elements. It can withstand long peri-
developed by SKF are available and have ods of operation under marginal lubrication
been proven successful in many applications. conditions. For additional information, refer
to NoWear coated bearings, page 1060
Integral sealing Black oxide
INSOCOAT
Black oxide coating of rings and rollers
Integral sealing can signiicantly prolong improves reliability and performance in INSOCOAT bearings are standard bearings
bearing service life by keeping lubricant in highly demanding applications, especially that have the external surfaces of their inner
the bearing and contaminants out. under low load conditions and high vibration. or outer ring plasma -sprayed with an alu-
The various types of capping devices that In addition, it improves corrosion protection minium oxide, impregnated with a resin
are available for SKF bearings are described and lubricant adhesion on the bearing sealant, to form a coating. It offers resistance
in Components and materials, page 24. surfaces. to the damage that can be caused by the
Information about which integral seal SKF also supplies customized black oxide passage of stray electric current through the
options are available for a particular bearing coating layers that are optimized for best bearing. For additional information, refer to
type is given in the relevant product section. tribological results and highest bearing per- INSOCOAT bearings, page 1030.
formance, produced using well-deined pro-
cesses and ine tuned to the individual steel Other coatings are available that provide an
grade, bearing type and size. SKF’s evalua- alternative to stainless steel bearings (espe-
tion and quality control technology for the cially for ready -to-mount bearing units) that
black oxide application process includes a are used in a corrosive environment.
Bearing execution
Table 1
Permissible operating temperatures for PA66 cages with various bearing lubricants

Lubricant Permissible operating temperature 1)

– °C °F
B.7

Mineral oils
Oils without EP additives, e g machine or hydraulic oils 120 250
Oils with EP additives, e g industrial and automotive gearbox oils 110 230
Oils with EP additives, e g automotive rear axle and differential gear oils (automotive), hypoid gear oils 100 210
Synthetic oils
Polyglycols, polyalphaoleins 120 250
Diesters, silicones 110 230
Phosphate esters 80 175

Greases
Lithium greases 120 250
Polyurea, bentonite, calcium complex greases 120 250
For sodium and calcium greases and other greases with a maximum operating temperature ≤ 120 °C (250 °F),
the maximum temperature for a polyamide cage is the same as the maximum operating temperature for the
grease

1) Measured on the outside surface of the outer ring; deined as the temperature that provides a cage ageing life of at least 10 000 operating hours.

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