Applicational advantages

An application incorporating a CARB® toroidal roller bearing provides the following:

Self-aligning capability

The self-aligning capability of the bearing is particularly impor­tant in applications where there is misalignment as a result of manufacturing or mounting errors or shaft deflections. To com­pensate for these conditions, the bearing can accommodate misalignment up to 0.5 degrees between the bearing rings with­out any detrimental effects on the bearing or bearing service life

Axial displacement

Previously, only cylindrical and needle roller bearings could ac­commodate thermal expansion of the shaft within the bearing. Now the toroidal roller bearing can be added to that list.

The inner and outer rings of the bearing can be displaced, with respect to each other, up to 10% of the bearing width. By install­ing the bearing so that one ring is initially displaced with respect to the other one, it is possible to extend the permissible axial displacement in one direction. In contrast to cylindrical and needle roller bearings that require accurate shaft alignment, this is not needed for toroidal roller bearings, which can also cope with shaft deflection under load. This provides a solution to many problem cases.

Long system life

The ability to accommodate misalignment plus axial displace­ment with virtually no friction enables this type of bearing to pro­vide benefits to the bearing arrangement and its associated components

• Internal axial displacement is virtually without friction; there are no internally, induced axial forces, thus operating condi­tions are considerably improved.

• The non-locating bearing as well as the locating bearing only need to support external loads.

• The bearings run cooler, the lubricant lasts longer and maintenance intervals can be appreciably extended.

High load carrying capacity

It is claimed that this toroidal roller bearing can accommodate very high radial loads. This is due to the optimized design of the rings combined with the design and number of rollers. It is also claimed that the large number of long rollers make CARB® bearings the strongest of all aligning roller bearings.

Also, these bearings can cope with small deformations and ma­chining errors of the bearing seating. The rings can accommo­date these small imperfections without the danger of edge stresses. The high load carrying capacity plus the ability to compensate for small manufacturing or installation errors pro­vide opportunities to increase machine productivity and uptime.

Increased performance or downsizing

For bearing arrangements incorporating this toroidal roller bearing as a non-locating bearing, internally-induced axial forces are prevented. Together with high load carrying capacity it is also claimed that:

• for the same bearing size in the arrangement, performance can be increased or the service life extended, or

• new machine designs can be made more compact to pro­vide the same, or even higher performance.

Reduced vibration

Self-aligning ball or spherical roller bearings in the non-locating position need to be able to slide within the housing seating. This sliding, however, causes axial vibrations which can reduce bearing service life considerably. Bearing arrangements that use CARB® toroidal roller bearings as the non-locating bearing are stiff because the bearing can be radially and axially located in the housing and on the shaft. This is possible because ther­mal expansion of the shaft is accommodated within the bearing. The stiffness of the bearing arrangement, combined with the ability of the bearing to accommodate axial movement, sub­stantially reduces vibrations within the application to increase service life of the bearing arrangement and related components.

Full dimensional interchangeability

C b a ‘f OPeratin9 hours 102 2 3 4 5 678910s 2 3 4 6 678910* 2 N r/min

The boundary dimensions of these toroidal roller bearings are in accordance with ISO 15:1998. This provides dimensional interchangeability with self-aligning ball bearings, cylindrical roller and spherical roller bearings in the same dimension se­ries. The range also covers wide bearings with low cross-sec­tions normally associated with needle roller bearings.

[1] Kinematic similarity in which the dimension of time is added to length and all peripheral flow velocities at any point within a machine are in a constant ratio to the veloci­ties at corresponding points of the similar unit.

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