Greasless Ball Bearings

[dual fours]

What do you think?  http://www.gizmag.com/greaseless-ball-bearings-coo-space-adb/37689/

[RallyeMike]

Thanks for the link. That looks really interesting.

My main question is.... the groove concept that allows the bearing to run unlubricated also sounds like it MUST be unlubricated to maintain the fine balance of ball separation. What happens to bearing life and function if dirt and debris get into the race? Are these bearings sealed units?

[dual fours]

https://translate.google.com/?tl=ja#auto/ja/I%20do%20not%20know%20if%20they%20are%20sealed  
yea you can me.

[RallyeMike]

I see now that there are several comments on the story posing the same types of questions. Some things are good in theory. Not so good in practical use. I think most people would miss greasing their balls anyway.

[Steve P.]

In theory this looks great, but I'd like to see them in real use. Truck axles. Both vertical and horizontal planes like car spindles and mowing deck spindles. How would they work in place of bushings where the axle would be used in back and forth motion?

The two bearings they show in the video clip have no load on them. To me, I want to see a side by side comparison under many types of loads...

Time will tell. If this turns out to be a winner I think it will be huge.. Look at the difference between heavy grease in a tranny and the super lite lube used now... Getting rid of friction is HUGE!!!!!   

[ws23rt]

I see this as a clever idea that would answer a need in many places where that extra friction of the cage is relevant.

Ball bearings are just one kind of bearing and are --by design-- for lighter duty and to carry thrust as well as radial loads.
cylindrical and spherical rollers have a larger rolling contact points for greater load carrying capacity and in most cases the extra friction of a cage would be insignificant. Also that idea may not be applicable to roller shapes other than ball type.

As for dirt and debris getting in?  I can't think of a type of bearing that will work for long with stuff getting in the contact area  (well maybe air bearings ) Also the idea of lubrication is to keep the rolling parts from touching in the first place. Without it lifespan will go down. At that point of contact their is deflection in the metal and fatigue will cause it to eventually fail. Lubrication is a cushion and it's molecules take a beating too. It will also breakdown eventually.

[Nacho-RT74]

I think most people would miss greasing their balls anyway.

Eeeeehm    

 

[Nacho-RT74]

Being serious! What about the heat by the friction? Grease takes part of that

[Steve P.]

Grease or no grease the heat is transferred into the parts that the bearing is attached to. Typical for our cars would be the spindle and hub.. But it seems to me that pretty much anything that has friction of mettle to mettle without a barrier of oil or grease will end badly. Just my .02, but for years of working on all kinds of machinery I will have to see proof of this idea before I buy into it.

[ws23rt]

If any roller type bearing runs --completely-- free it will consume no energy from sliding surfaces. Only a small amount from the flexing of the metal at the contact point and this depends on the load it sees. It will therefore gain little heat energy.

Friction happens when there is a sliding action between the metal surfaces. A bearing roller cage has that sliding surface and lubrication not only keeps the sliding surfaces apart it gains heat energy when it does. This topic started about a clever way to do away with a cage and this value does not translate as a plus to all applications.

Journal bearings (as in rod bearings for example) have -only- a sliding surface.  In this case the bearings carry a very heavy load and contact point is large to carry that load.  Lubrication keeps the metal from touching but heat is generated in the shearing action on the lubrication. (the same thing happens in a gear mesh).