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Easy Print Bearing

by mcg1355, published

Easy Print Bearing by mcg1355 Dec 19, 2012

Description

Here is a bearing that uses truncated elliptical rollers instead of balls. This is intended to be easy to print all as one print without having to try to break the bearings free. Theoretically it should just come off of the build platform working with no cleanup. This is the first thing I have made in openscad, as I just started learning it today in preparation for my printer’s arrival. Also I don't have my printer yet so don't know if it prints properly. Please try it out and let me know!

Update 1.1 (FIX): Still truncated elliptical rollers. Scaling fix so that roller ends are at same z level as ring edges (they were slightly off in the original version due to a 0.95 z scaling factor that I missed). I'm not sure if it is enough of a difference to mess up printing but I figured I'd fix it anyway. Also width changed to 21mm for closer roller packing.

Update 2.0: New roller profile! Now has a tiered or crowned roller profile to prevent x and y rotation of rollers. I realized that there was a possibility of unintentional x or y rotation with the truncated elliptical rollers from version 1.

Update 2.1: Slightly larger rollers to reduce play and also much tighter roller packing. Same profile as 2.0

Recent Comments

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I just printed v2.1 by scaling the STL its a little loose but works great once I freed each roller - thanks!
I think that's the key - less space between rollers. Will definitely give your next one a try!
Thanks for trying it out! Is there room to make the rollers larger as well? I have a revision (2.1) of v2.0 that has larger rollers and much smaller distance between each roller. I am just about to upload it as an update if you want to try it out.

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Instructions

Update 1.1 (FIX): Still truncated elliptical rollers. Scaling fix so that roller ends are at same z level as ring edges (they were slightly off in the original version due to a 0.95 z scaling factor that I missed). I'm not sure if it is enough of a difference to mess up printing but I figured I'd fix it anyway. Also width changed to 21mm for closer roller packing.

Update 2.0: New roller profile! Now has a tiered or crowned roller profile to prevent x and y rotation of rollers. I realized that there was a possibility of unintentional x or y rotation with the truncated elliptical rollers from version 1.

Update 2.1: Slightly larger rollers to reduce play and also much tighter roller packing. Same profile as 2.0

I tried to design is so it would just print all at once and come off the platform working without cleanup. The things that may be problematic are: rollers breaking free from platform during print, too small of a gap between rollers and inner and outer ring, you may need to reposition the print so that it is not partially below the build platform (there are negative z values in the model, I don't know if this is a problem), inner ring or rollers falling out, the geometry may be too dense as well (as I don’t know what kind of resolution is required to get good prints), there's probably something I don't know about yet.

Dimensions: Outer radius: 50mm (total 100mm across) Inner radius: 25mm (total 50mm across) Thickness: 20mm (21mm for V1.1)

I've attached my openscad file as well so you guys can use it or change it or fix my mistakes. I was trying to make it somewhat parametric but couldn't get the roller number to scale appropriately. The two driving dimensions are the outer radius for the two rings and the thickness for the roller size. The number of rollers will have to be changed manually (in the last statement) if the outer radius to thickness ratio changes.

I also added a sketchup file so you can easily see the shape and design of the rollers / channel.

I just printed v2.1 by scaling the STL its a little loose but works great once I freed each roller - thanks!
v2.0 Looks very cool, printed without a hitch -- sadly does not work. Rollers are too free to wobble off axis causing friction. Perhaps adding 1-2 more rollers will limit mobility along this axis.
Thanks for trying it out! Is there room to make the rollers larger as well? I have a revision (2.1) of v2.0 that has larger rollers and much smaller distance between each roller. I am just about to upload it as an update if you want to try it out.
I think that's the key - less space between rollers. Will definitely give your next one a try!
Prints nice, rollers fall out, could be my inexperience and printer calibration, but sliced in slic3r no problem. This was from the first .stl that was up.
Awe man that's no good. Thanks for trying it out! So I take it the rollers are just too small? I can scale them up easy enough as I was mainly guessing for what kind of gaps are printable. Any suggestions for how much larger they could be? They're at 0.95 times the channel size that they run in currently.
What's the difference between this at thingiverse.com/thing:37429 ? They look quite similar, and I'm curious whether it's "two great minds think alike" or one is inspired by the other, etc.? I ask because I literally just posted on that thing a minute ago that it'd be cool to have the bearing as an OpenSCAD module so that it's easily reuable in other other engineering designs. And yours is coded in OpenSCAD. Thingiverse is so cool! :-)
Wheel with Cylinder Bearings V3
by cymon
I hadn't seen that one before! It looks like it is very much a great minds think alike scenario. I would guess that either of our designs would work to achieve the same goal. It looks like the rollers in his/her bearing design are more rectangular in profile compared to the ones in my bearing. I use an elliptical shape in V1.1 and a series of curves in V2.0 for the roller profile in my bearings. I used curves because I thought a gradual change would be easier to print than hard corners, but I'm shooting in the dark as I don't have my printer yet. I was just going for something that wouldn't need support material or cleanup while trying to prevent the rollers from falling out or binding. I only started learning OpenSCAD yesterday so there may be many mistakes in there...
That's a pretty neat idea using truncated elliptical rollers!
Thanks! I realized they may rotate in the x and y direction (i.e., perpendicular to bearing rotation) unintentionally. I just updated and uploaded a second roller profile (kind of a curved tiered shape) that is intended to prevent this from occurring.
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