Nonsliding Roller Bearing FAIL

WARNING this does not work at all. Its an absolute disaster.
I mostly publish this here as
– it seems to be quite an interesting concept 
– others will be warned before attempting the same thing

Theory sidenote

Note that only odd numbers of layers of rollers will work. Even numbers of layers of rollers would bind up the core to the outer ring. Similar too how an odd number of gears in a circle does block itself. I've seen designs making this mistake.

In the name of sharing failures:

This is a roller bearing that 
– needs no cage to keep the rollers apart.
– can be printed in one piece.

The special thing about it:
It (theoretically) could have has less sliding friction than a roller bearing with a cage.
This is archived through the central rolls.
Those let the inner and outer rolls roll on rolls.
This bearing can can take both radial and axial force.
It should run under some (axial) load so that rolling is ensured!

A pre-load would work to but than a zero clearance print with post assembly is required.
(split the ring or better the center piece in two for that)

A little bit of unavoidable friction occurs at the slanted top & bottom retainers but this shouldn't hurt. (gears also have a tiny sliding friction component)

It was inspired by this thing: 
http://www.thingiverse.com/thing:55515

Which in turn was inspired by emmets popular gear bearing. http://www.thingiverse.com/thing:53451

This needs improvement !

edit2: no, I think this is just not fixable for FFF printing

My test-print fused together on the outer edge so hard that I broke the ring when I tried to break the outer rollers loose. At the same time the inner rollers where so loose that they almost slid out. Also the small diameter rollers didn't turn out round enough to roll - even under load.

Overall an absolute disaster. I doubt this is fixable.
With gear-bearings the teeth-numbers most likely won't go together.
Or only with way too many teeth.

Instructions

There are a lot of parameter combinations that do not work.
=> Change one at a time.

Low roller numbers lead to the necessity of high bearing diameters.
High roller numbers make the rollers small and lead to the necessity of high center piece diameters (8 to 12 rollers are good I think)

Category: Other