Double-row ball bearings of oblique contact correspond by their own construction and function to pair of one-row ball bearings with oblique contact in „O“ – type configuration. They have rather deep orbits on both rings and are may not be disassembled. In case of „E“ type construction, a filling opening is made on one side.
With optimal size of the balls and their conformity to the raceways relatively high load ratings are achieved. They can carry axial and radial loads in both directions
and are suitable even for high rotation rate. In case of “E” type bearings assembling, it must be done so that the prevailing axial force acts on the ball row on the side without the filling groove.
Main dimensions of double row angular contact ball bearings specified in the dimension tables are in accordance with the international standards ISO 15. The bearings are commonly produced in the basic P0 tolerance class. Double row angular contact ball bearings are very sensitive to the misalignment of the rings.
Bearings with shields or seals
Double row angular contact ball bearings with sealing on one or on both sides are manufactured with metal shields (ZR, -2ZR) or with seals (RSR, -2RSR). The sealing rings made of rubber, vulcanized on metal reinforcing ring, provide an effective friction type sealing. The bearings are manufactured in the design with a seal and a flat collar of the inner ring (RSR, -2RSR).
Bearings with seals are suitable for operation within the temperature range from -30°C to 110°C.
Bearing deliveries with sealing capacity within 180°C (RS2, -2RS2, resp. RSR2, -2RSR2), or eventually delivery of bearings with other sealing design, must be negotiated in advance.
Bearings sealed on both sides -2ZR, -2RSR) are filled with a quality lubricant the properties of which usually ensure the lubrication during the whole bearing life under normal operating conditions. The bearings of this design cannot be relubricated. They can be used within the operating temperature range from -30°C to 110°C. The delivery of bearings with different lubricant should be discussed with the supplier in advance.
Lubrication
For bearings sealed on both sides, the designation of the lubricant filling different from standard lubricant is indicated by a symbol combination. The first two letters indicate the operating temperature range (a symbol in accordance with STN 02 4608) and the third identifies the lubricant name.
TL – Lubricant for low operating temperatures (from -60°C to 100°C)
TM – Lubricant for medium operating temperatures (from -30°C to 110°C)
TH – Lubricant for high operating temperatures (from -40°C to 250°C)
TW – Lubricant for low and high operating temperatures (from -40°C to 150°C)
Note: The symbols of lubricants for medium operating temperatures need not to be marked on the bearings.
Cage
The single row deep groove ball bearings of the basic design are equipped with a pressed cage made of steel sheet, guided on balls, which is not designated. The cages for double row angular contact ball bearings are manufactured in two version in dependence on the inner construction of the bearing. (see picture).
