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

By Bart van Oevelen - In Products - 11 Feb 2021

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.”

Impression of peak stress reduction

Selecting the cage

There are some options when it comes to the FAG QP51 Cylindrical Roller Bearings range: the rollers are available in either a brass or plastic casing. The selection depends on the type of vibratory application. When using higher radial load gears, a brass casing is more stable than a plastic one. The MPAX casing is the strongest option. This has a one-piece structure made from solid brass. Therefore, the MPAX casing is suitable for any type of application of vibrations.

Last but not least, some advice from Gerard: “It is important to choose an equal or better casing when replacing the old one. A TVP casing (plastic) may be replaced by a TVP or MPAX casing, but a MPAX casing may never be replaced by a TVP casing.”

Are you looking for a replacement FAG QP51 Cylindrical Roller Bearing? Or do you need help selecting a suitable bearing type for your project? We are here to help you!

Different cage types: MPAX and TVP
Go to our QP51 Cylindrical Roller Bearings
Bart van Oevelen Product Manager baoe@abf.store +31 (0)165 722 011

More blogs view all