how to increase a bearing life?

Answer 1

There's no one single answer to that question.

If you've been tasked to keep bearings operating then keep them clean, appropriately lubricated (use the recommended lubrication). Also make sure the maching they're attached to is in good working order. Vibrations or other forces (such as excessive load) will translate into shorter bearing life as well....so be sure the rest of the machine works properly too.

Truthfully, the most important part of extending bearing life is a good design and bearing selection. There is a lot of science behind bearings. Selecting between a ball bearing, roller bearing, journal bearing, etc. is critical if the bearing is to last. On motors for example, some bearings are designed to operate best if there is some force perpendicular to the shaft (i.e. the shaft turns the load directly), while other motor bearings operate best if the shaft is coupled to another shaft which bears the load.

As always, you get what you pay for. Correct tolerances help increase bearing life a great deal. Tolerance costs money, so you may not get the same life out of a cheaper bearing as compared with a more expensive one. The heat treatment of the shaft is also critical. If the bearing asks for between 58 and 60 Rockwell C, that's what it is designed to have. Make sure it gets it.

To top it all off, everything mentioned above is based on your design needs. If your a maker of machine tools, you'll need to account for everything I listed and more to keep perfect tolerances time after time. If your bearing application is for, say, a doorknob to turn, then you need to consider almost none of this since the functionality of the doorknob will not deteriorate due to a little bit of wobble.

Answer 2

Survey tells that the more than 80% bearings are getting failed due to lubrication problem.

Lubrication programme should be scheduled to take care of all these factors.

Use correct grade of oil WRT temperature,rpm,starting torque,type of loading and surrounding.
Use good MOC oil seal .
Always fill the oil through the oil cup.
keep the breathers clean.
Fill correct quantity of oil.
Replace the oil as per manufactureres standards.
Keep the oil in safe,closed space.
Use small tins of oil/grease.Avoid barrels as far as bearings are concerned.
keep the equipment away from effluent/safe-guard it .
Analyse the sample periodically for foreign material.
Use the oil with good quality additives.
Remaining problems are improper alignment,improper fitment of bearings,improper selection of bearings,improper venting(breather need to be periodically cleaned.),dirty equipment(can choke the fins of motor,pumps,compressors which are meant for heat transfer).
Open the bearing cover of a new bearing only when it is needed.
Use the proper bearing fitting tools like sleeves and spacers.
Dont stake the bearings,as it affects the tolerences of bearing in temperature.

Answer 3

If it is properly sized, mounted parallel to the shaft, of sufficient capacity for load, and is either sealed or protected against external contamination then the only other factor is keeping the right lubricant in it.

Answer 4

Keep it greased. Plain and simple. Motor bearings need constant PM's.