Double row tapered roller bearings
SKF manufactures double row tapered roller bearings in the TDO (fig. 1) and TDI (fig. 2) designs, in many variants and with different features (→ Designs and variants). Depending on the design, these bearings can accommodate heavy radial loads, axial loads in both directions and have a high degree of stiffness. Double row tapered roller bearings are typically used in gearboxes, hoisting equipment, rolling mills and machines in the mining industry, e.g. tunnelling machines.
High load carrying capacity
Because of their second row of rollers, double row tapered roller bearings are suitable for heavy radial and axial loads. The axial load carrying capacity of tapered roller bearings increases with increasing contact angle α. The size of the contact angle, which is usually between 10° and 30°, is related to the calculation factor e (→ product tables): the larger the value of e, the larger the contact angle.
Axial loads in both directions
Double row tapered roller bearings locate the shaft in both directions with a specific axial clearance or preload.
Double row tapered roller bearings provide a stiff bearing arrangement.
The optimized roller end design and surface finish on the flange (fig. 3) promote lubricant film formation, resulting in lower friction. This also reduces frictional heat and flange wear. In addition, the bearings can better maintain preload and run at reduced noise levels.
Long service life
The crowned raceway profiles of basic design bearings and the logarithmic raceway profiles of SKF Explorer bearings optimize the load distribution along the contact surfaces, reduce stress peaks at the roller ends (fig. 4), and reduce the sensitivity to misalignment and shaft deflection compared with conventional straight raceway profiles (fig. 5).
Enhanced operational reliability
Optimized surface finish on the contact surfaces of the rollers and raceways supports the formation of a hydrodynamic lubricant film.
Consistency of roller profiles and sizes
The rollers incorporated in SKF double row tapered roller bearings are manufactured to such close dimensional and geometrical tolerances that they are practically identical. This provides optimal load distribution, reduces noise and vibration, and enables preload to be set more accurately.