Tapered roller bearings are widely used because they have greater loading capacity, accepting radial and thrust loads at the same time. Due to the capability of setting optional clearances by adjusting parts of paired bearings, such bearings with pre-load can be used in order to increase the rigidity of shafts or improve the turning accuracy, depending on the machine function.
On the other hand, tapered roller bearings generate greater bearing torque, compared with ball bearings and cylindrical roller bearings. This problem is more complicated by featuring greater frictional torque, caused by sliding friction between the rib of the inner ring and the end face of the rollers.
The author believes that the lowering of the bearing torque by explicating causes of effects activated to the torque of the tapered roller bearings, can result in improving the reliability of tapered roller bearings and extending their applications. Effects expected will be temperature reduction at operation; easier pre-load control when assembling; improvement in seizure protection; and improvement in pre-load decreasing.
The author will introduce characteristics of tapered roller bearings which run in the lower speed ranges where the sliding friction at the rib area is influential, as well as the results of tests of torque reduced bearings through bearing design.