FAG QP51 Cylindrical Roller Bearings: an impressive case of remarkable precision

FAG QP51 Cylindrical Roller Bearings are used for applications that involve extreme vibrations. As such, they are very resilient. Naturally, this requires a special design. And everything that is special deserves some extra attention. Yet, little publicity is given to the QP51 suffix, for reasons unknown. What is so remarkable about the QP51 design? We decided to go to manufacturer Schaeffler and look for answers.

Needless to say, we came to the right place. Engineer Gerard Versteeg explained exactly what it is that makes these bearings so special.

“The QP51 Cylindrical Roller Bearings are a very specific type of bearing. This type of bearing is only used in a limited number of situations and almost always under the supervision of an engineer or specialist. For this reason, there is not a lot of information readily available as is the case with more common bearing series.”

Unravelling the concept

As there are many alternative options that deal with vibrations or are shock-proof, we asked Gerard under which circumstances specifically the QP51 Cylindrical Roller Bearing should be used.

“There are situations that involve such great forces in the applications of vibrations, that the shaft can get bent. This is, for instance, the case with dam wall vibrators. A bent shaft in standard cylindrical roller bearings leads to peak stress on the side of the cylinder roller. The result? Increased wear and a shortened lifespan. FAG QP51 Cylindrical Roller Bearings are designed specially to reduce this stress. This is because both the inner and outer ring have slightly crowned raceways. This means they are not flat but instead have a rounded profile. Because of this, QP51 Cylindrical Roller Bearings do have a slightly lower load rating. However, in practice, the reduction of the peak stress leads to a longer lifespan. Therefore, the decision to opt for a QP51 type is usually made by multiple parties.”