We have a project that requires us to use a qty of 4, Ø2" yoke roller bearings mounted two per side on a trolley that roll on a steel track. The maximum total weight that we estimate on the track at any given time while in service will be between 8k to 12k lbs. This will be distrubuted too the 4 rollers which each have a capacity of 8,000 lbs each. So there would about 2k-3k per roller.
We will be using standard yoke roller bearings that have an outer ring hardness at 58-62 Rockwell C or 58-62 Rc. Our Track is hardened to 52-58 Rc. Knowing that the track has a hardness less than that of the bearing, wouldn't it stand to reason that the track will wear out before the bearing? This is unacceptable for this project.
We need a solution so we can make the bearings the wear item on this project. The track would take many man hours to replace , where a bearing would take very little time to replace and cost much less than a new track.
We would need to increase the track hardness to slightly higher than the bearing or lower the hardness of the bearing to make the bearing the wear item instead of the track. The downside to this is that I would sacrifice bearing L10 Life by lowering the hardness of the outer ring.
We would love some help solving this issue if anyone has had any experience with this problem.
****UPDATE 1/14/2020***** Since I posted this question, I have spoken with quite a few other mechanical and manufacturing engineers who specialize in bearing and track design. They all pretty much explained me the same thing that using a a track that is 40-58 Rc will work just fine with a yoke roller that has an outer ring hardness of 58-62 which is the industry standard for that type of bearing. The bearing internal rolling elements and seals will wear out long before the track or the OD of the outer. Being that the track is 52-58 Rc it should endure many yoke roller swap outs over the years with the loads and application this is being used with. I'd like to thank everyone for your time and effort put into helping us come to a conclusion of this issue.