# Axial self-aligning roller bearings

## Description

In self-aligning roller bearings, the raceways are located at an angle to the bearing axis; this bearing type includes a huge number of asymmetric barrel rollers. In addition to high axial forces, these bearings are also capable of carrying radial loads (max. 55% of Fa). They can be used at relatively high speeds. Self-aligning roller bearings are not sensitive to misalignments and compensate for shaft deflection.

## Dimensions/standards

In self-aligning roller bearings, the main dimensions are standardized according to ISO 104 (Roller bearings – thrust bearings – boundary dimensions), DIN 616 (Roller bearings – boundary dimensions) and DIN 728 (Self-aligning roller bearings, one direction).

## Tolerances

SLF produces axial self-aligning roller bearings in standard tolerances (PN) according to DIN 620-3 (Roller bearing tolerances – tolerances for radial bearings) and ISO 199 (Thrust bearings – geometric product specification and tolerances). We can supply different tolerance classes or special tolerances upon request).

## Bearing design types

Self-aligning roller bearings are separable, single row roller bearings. The raceways in the solid shaft and housing washers are situated at an angle to the bearing axis. In the housing washer, the raceway has a concave design. This design provides angular movability, which is very important for many applications. The cage with a huge quantity of asymmetric barrel-shaped rolling elements provides the roller cage assembly. Together with the shaft washer, the roller cage assembly is a non-detachable unit.

Since the raceways are inclined to the bearing axis, self-aligning roller bearings can simultaneously carry very high axial loads in one direction and radial loads. Thanks to the maximal quantity of large and long barrel rollers, these bearings are designed for maximum load carrying capacity and are also suitable for the highest loads and stresses.

## Cage

Self-aligning roller bearings are equipped with steel plate or brass cages (designation suffix MB).
These cages are very strong and suitable for high temperatures, as well as all commonly used greases/ lubricants.

## Working temperature

SLF self-aligning roller bearings with a maximum 120 mm outer diameter are standard stabilized in dimensions by S0, meaning that they are subjected to heat treatment that makes them usable up to a working temperature of 150 °C. Above a 120 mm outer diameter, the self-aligning roller bearings are standard stabilized in dimensions by S1, meaning that they are heat treated to make them usable up to a working temperature of 200 °C. However, as a rule, the maximum working temperature is not limited by the dimensional stability of the bearing rings and rolling elements; it is frequently limited by the lubricant/ grease. If you are uncertain or have specific questions regarding our bearings’ temperature limits, don’t hesitate to contact the SLF team.

## Greasing/ lubrication & sealing

We manufacture self-aligning roller bearings without seals. Consequently, the bearing location must be sealed around/ on the surrounding components. The sealing must ensure that no moisture and contaminants can enter the bearing and that no lubricant is lost.

The self-aligning roller bearings are delivered ungreased but must be lubricated with oil or grease. Choose the lubricant according to the application.

## Dimensioning

### Dynamic equivalent load

(Permissible) Radial load of the bearing Fr s maximal 55% of the axial load Fa.


 $$P = F_a + 1,2 * F_r$$ when $$F_r \leq 0,55 * F_a$$
 P dynamic equivalent load [kN] Fa axial dynamic load [kN] Fr radial dynamic load [kN]

### Axial minimum load

To avoid slippage between elements in contact, the self-aligning roller bearings must be sufficiently loaded. For this purpose, an axial minimum load Fa min is necessary.
In vertical bearing arrangements, the axial load resulting from the weight of the components run on bearings combined with the external forces is higher alone than the minimal load required.
Should this value not be met, contact an SLF application technician.


 $$F_{a~{min}} = 0,0005 * C_{0a} + k_a \left(\frac{C_{0a} * n} {10^{8}}\right) ^{2}$$
 Fa min axial minimal load [kN] C0a static load rating [kN] ka factor to find out axial minimum load [-] n speed [min-1]
 Series Factor ka 292..E 0,6 293..E 0,9 294..E 0,7

### Static equivalent load

Radial permissible bearing load F0r is maximal 55% of the axial load F0a.


 $$P_0 = F_{0a} + 2,7 * F_{0r}$$ when $$F_{0r} \leq 0,55 * F_{0a}$$
 P0 static equivalent load [kN] F0a static equivalent load [kN] F0r radial static load [kN]

### Static load safety factor

For statically loaded self-aligning roller bearings, you must check the static load safety factor S0 in addition to the nominal lifetime L (L10h).

$$S_{0} = \frac{C_0}{P_0}$$
 S0 static load safety factor [-] C0 static load rating [kN] P0 static equivalent load [kN]