I have in mind an application where I need a long arm sweeping semi-circularly in a horizontal plane. The BBH-01 would be a nice choice for the hub but I don’t know how much torque I can apply perpendicular to the BBH-01 axis of rotation before the hub begins to bind and/or the ball bearing fails prematurely. The application would make it difficult to add a counterweight.
Of course, I can always buy one and test to destruction, but I thought I’d ask first if anyone has a data point or two.
If a single BBH-01 doesn’t work, I could work up the equivalent of the hub of a bicycle wheel with two BBH-01s and associated bits. This also would be difficult in the application, although less so than adding a counterweight.
Long arm? What load? Hard to say. Any appreciable load will probably overwhelm the bearing. that’s a 4-40 screw holding it together, if I remember. That should tell you something.
See my “Little Cat” project. I use these bearings in each leg on the body.
The torque created by my approximately 8" long legs is right at the questionable point for these bearings, in my initial assessments. I’m pretty sure a long arm would overwhelm them. I’m considering making a bigger bearing for my use.
Can you support an axle (1/4") between two small sealed bearings, and swing your arm from that? I take it that weight of the bearing assembly is not so much of a problem as in a mobile robot?
Well, I’m still noodling, but as a WAG let’s say it’s 8oz at the end of a 12in arm, so the torque is approximately 100in-oz. This is small potatoes in some worlds, big in others. I lack the experience with SES parts to know which world I’m in
That’s just the sort of info I was looking for. (Nice design by the way! Thanks for the pointer.)
That’s a beefier version of what I was thinking about. I’ll probably try it with the BBH-01 first because I can prototype more quickly using SES parts. And you’re right, this will be a stationary robot—think specialized parts picker—and extra mass at this particular place in the assembly is pretty innocuous (might need a bigger motor upstream in the assembly to deal with the added inertia).
