Spherical roller bearings

This bearing suits lower-speed roll neck bearings, such as steel rolling mills. Spherical roller bearings can be applied at low and medium speeds, and the rolling speed should not exceed 12 meters/second.

Since the usable height is restricted, spherical roller bearings of size series 240 and 241 are usually used. These bearings have a small section height.

• Spherical roller bearings are self-engaging; they can withstand radial and axial forces. Since the axial internal clearance is 4~6 times the radial internal clearance, its axial guidance precision is low and has self-aligning ability.

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• Application characteristics of spherical roller bearings in rolling mills

• It has a strong self-aligning ability. The bearing seat can be easily supported on the roll frame, and the inaccuracy of the roll frame and the deflection of the roll neck are compensated in the bearing;

• The self-aligning roller bearing is also used to bear the prestress of fixing the bearing seat bracket with the tie rod, so it cannot be automatically calibrated in this case;

• In the case where it must be possible to remove from the roll neck and the rolling speed is low, the inner rings can have a loose fit;

• Like the tapered roller bearing, the spherical roller bearing can also turn the spiral groove in the bearing hole to better lubricate the mating surface;

• In the place where the inner ring of the self-aligning roller bearing and the roll neck are closely matched, if the tapered hole bearing is used, the installation and disassembly are the easiest;

• Hydraulic methods can assist in mounting. Spherical roller bearings are also used for cantilever-mounted rolls because they can be aligned with the considerable deflection of the rolls that occurs under these conditions;

• An additional axial bearing must be used in conjunction with the support for the roll-formed part.

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• The structure of spherical roller bearings

• Depending on the internal design, spherical roller bearings have three standard structural forms: CC, CA, and E.

• Type CC means that the spherical roller bearing has symmetrical rollers, no flange inner ring, a non-integral guide ring between the two rows of rollers centered on the inner ring, and each row has a compressed steel window cage.

• Type CA means that the spherical roller bearing has symmetrical rollers, a flange on the inner ring, a moving retaining ring, and a solid brass cage.

• Type E means that the spherical roller bearing has symmetrical rollers, the inner ring has no flange, a non-integral guide ring between the two rows of rollers, and each row has a stamped steel window cage. The outer ring has an annular groove and three lubrication holes.

The structure diagram is as follows:

• The above three are open spherical roller bearings. They can also be sealed. This type of bearing may have grooves on the side of the outer ring.

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• There are also sealed spherical roller bearings, which have the following characteristics:

• Has the same characteristics and internal design as open spherical roller bearings,

• The standard configuration is a cylindrical hole.

• It has been pre-filled with grease and cannot be cleaned.

• Except for bearings with model suffix W, there is an annular lubrication groove on the outer surface of the outer ring and three lubrication holes in the groove.

• The bearing has contact seals on one or both sides and is made of one of the following materials:

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--NBR nitrile rubber with added steel frame (model suffix CS or RS)

--HNBR hydrogenated nitrile rubber with steel skeleton reinforcement (model suffix CS5 or RS5)

--FKM fluoro rubber with steel frame reinforcement (model suffix CS2)

--Steel frame with G-ECOPUR (a polyurethane material) sealing lip

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• The seal is held in a groove in the outer ring with a lip against the inner ring; in larger bearings, the seal is held in place by a snap ring. (As shown below)

The lubrication period of sealed bearings is the same as the bearing life, making it almost maintenance-free.

• Designs

• FV Spherical roller bearing