Bearing 51256X

Tapered Roller Thrust Bearings
These are thrust bearings containing tapered rollers. TT-type bearings, which have a
rib on the housing washer, can accurately guide the shaft in the radial direction. TTFtype
bearings, which have no rib on the housing washer, can tolerate some eccentricity
during operation.
Spherical Thrust Roller Bearings
These are thrust bearings containing barrel-shaped rollers (convex rollers). They
have a self-aligning capability and are free of any influence of mounting error or shaft
deflection. Besides the original type, the E type with pressed cages, and the EM type
with machined brass cage for high load capacity are also available. Their bearing
numbers are suffixed by E.
Since there are several places where lubrication is difficult, such as the area between
the roller heads and shaft washer rib, the sliding surfaces between cage and guide
sleeve, etc., oil lubrication should be used even at low speed.
The cages in the original type are machined brass.
Tolerances and Running Accuracy
Thrust Ball Bearings...................................................Table 2.5 (Pages A26 and A27)
Cylindrical Roller
Thrust Bearings......................................According to Table 2.5 (Pages A26 and A27)
Tapered Roller Thrust Bearings................................Table 2.6 (Page A28)
Spherical Thrust Roller Bearings.............................Table 2.7 (Page A29)
Recommended Fits......................................................Table 3.3 (Page A35)
Table 3.5 (Page A36)
Thrust Ball Bearings
Cylindrical Roller Thrust Bearings
Tapered Roller Thrust Bearings
Spherical Thrust Roller Bearings
For inch design tapered roller thrust bearings, please contact NSK.
Dimensions Related to Mounting
The dimensions related to mounting of spherical thrust roller bearings are listed in
the Bearing Table.
If the bearing load is heavy, it is necessary to design the shaft shoulder with ample
strength in order to provide sufficient support for the shaft washerib.
Permissible Misalignment
The permissible misalignment of spherical thrust roller bearings varies depending on
the size, but it is approximately 1° to 2° with average loads.
Minimum Axial Load
It is necessary to apply some axial load to thrust bearings to prevent slippage between
the rolling elements and raceways. For more detail