The spherical roller bearing is a bearing in which the drum-shaped roller is assembled between an inner ring having two raceways and an outer ring having a spherical race.

Spherical roller bearing

Spherical roller bearings have two rows of rollers that are primarily subjected to radial loads and can also withstand axial loads in either direction.

High radial load capacity, especially suitable for heavy or vibration loads, but not for pure axial loads.

The outer ring raceway of this type of bearing is spherical, so its self-aligning performance is good and it can compensate for the coaxiality error.

There are two rows of symmetrical spherical rollers, the outer ring has a common spherical raceway, and the inner ring has two raceways inclined at an angle to the bearing axis, which has good aligning performance.

When the shaft is bent or installed with different cores, the bearing can still be used normally. The centering property varies with the bearing size series. Generally, the allowable centering angle is 1~2.5°.

This type of bearing has a large load capacity.

In addition to being able to withstand radial loads, the bearing can withstand axial loads in both directions and has good impact resistance.

In general, spherical roller bearings allow for lower operating speeds.

The spherical roller bearing is divided into two different structures: symmetric spherical roller and asymmetric spherical roller according to the roller sectional shape.

Asymmetric spherical roller bearings are early products, mainly for mainframe maintenance services.

Symmetric spherical roller bearings are rarely used when designing a new host.

The internal structure has been completely improved in design and parameter optimization, and it can withstand greater axial loads than the previously produced spherical roller bearings.

This type of bearing has a lower operating temperature and can be adapted to higher speed requirements.

According to the inner ring with or without the ribs and the cage used, it can be divided into two types: C type and CA type.

The C-type bearing features the inner ring without rim and adopt stamped steel plate holder.

The Type CA Trian bearing features a rib on both sides of the inner ring and a solid body cage.

In order to improve the lubrication of the bearing, the user can provide the spherical roller bearing with an annular oil groove and three oil holes in the outer ring, which is represented by the bearing rear code /W33.

Spherical roller bearings with inner ring oil holes are also available upon request.

In order to facilitate the loading and unloading and replacement of bearings, the tapered roller bearing with inner bore is also available. The taper is 1:12, and the rear code is K.

In order to meet the requirements of special users, bearings with a taper of 1:30 are also available, with the rear code K30.

The tapered bearing of the inner hole can be directly mounted on the tapered journal by a lock nut, or the bearing can be mounted on the cylindrical journal by means of an adapter sleeve or withdrawal sleeve.

In order to ensure that the bearing is prevented from causing harmful slippage between the raceway and the roller due to centrifugal action at high speed, the bearing should withstand a certain minimum radial load, and the size can be estimated as follows:

Fr = 0.02C

In the formula:

Fr — minimum radial load N

C—the basic dynamic load rating of the bearing N

Equivalent dynamic load

P=Fr+Y1Fa when Fa/Fr e

P=0.67Fr+Y2Fa when Fa/Fr e

In the formula:

P-equivalent dynamic load N

Y1 Y2—Axial dynamic load factor

Equivalent static load

P0=Fr+Y0Fa

In the formula:

P0 – equivalent static load N

Y0—axial static load factor

Applications

Mainly applicable cages:

  • Stamped steel plate reinforced cage (suffix E)
  • Stamped steel plate cage (suffix CC)
  • Glass fiber reinforced polyamide 66 cage (suffix TVPB)
  • Machined brass two-piece cage (suffix MB)
  • Machined brass integral cage (suffix CA)
  • Stamped steel plate cage for vibration occasions (suffix JPA)
  • Brass cage for vibration applications (suffix EMA)

Even for the same structure, the code on the bearing may be different.

The main application:

  • Paper machine
  • Speed reducer
  • Railway vehicle axle
  • Rolling mill gearbox housing
  • Rolling mill roller
  • Crusher
  • Vibrating screen
  • Printing machines
  • Woodworking machinery
  • Various industrial speed reducers
  • Vertical belt bearing

Installation

The spherical roller bearing is equipped with a roller-shaped roller bearing between the inner ring having two raceways and the outer ring having spherical race.

The center of curvature of the outer raceway surface is identical to the center of the bearing, so it has the same self-aligning function as the self-aligning ball bearing.

When the shaft and outer casing are deflected, the axial load in both directions can be automatically adjusted.

The radial load capacity is large, and it is suitable for heavy load and impact load.

The inner diameter of the inner ring is a tapered bore bearing that can be mounted directly.

Or use the adapter sleeve and the removal cylinder to mount on the cylindrical shaft.

The cage uses steel stamping cage, polyamide forming cage and copper alloy cage.

For self-aligning bearings, the intermediate mounting ring prevents the outer ring from tilting and rotating when the shafted bearing is inserted into the housing shaft hole.

It should be remembered that the balls of some sizes of self-aligning ball bearings protrude from the sides of the bearing.

Therefore, the intermediate mounting ring should be recessed to prevent damage to the balls.

A large number of bearings are generally installed by mechanical or hydraulic indentation.

For detachable bearings, the inner and outer rings can be mounted separately.

This simplifies the installation process, especially when the inner and outer rings require an interference fit.

When loading a shaft with the inner ring in place into a bearing housing that already contains an outer ring, care must be taken to check that the inner and outer rings are properly centered to avoid scratching the bearing raceways and rolling parts.

If the cylindrical and needle bearing are fitted with an inner ring without flange ribs or an inner ring with flanged sides on one side, it is recommended to use a mounting sleeve.

The outer diameter of the sleeve shall be equal to the inner ring raceway diameter F, and the tolerance for machining shall be d10.

Drawn cup needle roller bearings are preferably mounted using a mandrel.

Clearance

For the axial clearance of the spherical roller bearing, the adjusting nut on the journal, the adjusting washer and the thread in the bearing housing hole can be used, or the pre-tightening spring can be used for adjustment.

The size of the axial clearance is related to the arrangement of the bearing when it is installed, the distance between the bearings, and the material of the shaft and the bearing housing, which can be determined according to the working conditions.

For high-load and high-speed spherical roller bearings, when adjusting the clearance, the influence of temperature rise on the axial clearance must be considered, and the amount of clearance reduction caused by temperature rise should be estimated.

That is to say, the axial clearance should be adjusted to be a little larger.

For bearings with low speed and vibration, no clearance installation or preload installation is required.

The purpose is to make the roller and the raceway of the spherical roller bearing have good contact, and the load is evenly distributed to prevent the roller and the raceway from being damaged by the vibration shock.

After adjustment, the size of the axial clearance is checked with a dial gauge.

The method is to first fix the dial gauge to the fuselage or the bearing seat, so that the dial gauge contact bears against the smooth surface of the shaft, and pushes the shaft along the axial direction, and the maximum swing amount of the hands is the axial clearance value.