Geared, Reversible, Backdrivable CVT

Started the linear motion for the CAM. I was initially thinking about using MGN3 linear rails until a realized that each rail is over 100 bucks. Instead, I decided on linear bearing based motion with 3mm rods similar to how the ratio changes. Here’s some problems I ran into:

• Cheap MGN rails were way too big so I decided on the linear bearings (I spent way too long searching for cheap MGN3 linear rails)
• I initially wanted to put the rods between the yellow and blue plate, but after sketching it I realized the tolerances were too sketchy.
• Initially I was going to do one main CAM in the center, but I realized when the CAM is pushing the shaft to the outside, the angle is weird so the force is basically transmitted perpendicular to the direction of the motion, which really cooks efficiency. So instead I decided on 2 smaller CAMS that are belted to the main gear.

some future/long term problems I need to fix:

• I don’t think there’s enough space for the belts and cams, so this whole design might be fried
• The 3mm rods aren’t constrained on their ends, so I have to figure out a way to do that (right now its only held by friction).
• The motion of the driven gear will oscillate a ton because of the CAM. One potential solution is to use elliptical gears and have the gears engage only in a certain phase where its speed is high (so its not stopping)
• There’s something similar to the coaxial effect from swerve drives in this gearbox too: I’m gonna call it the CVT effect. When the gear ratio changes, the linear motion makes the gear change phases. Something similar happens because of the CAM, but this isn’t that big of a problem. But when in doubt, assume software can account for it.

Mounted the CAM gear, added a front plate, and added screws. I ran into a problem where one of the hubs hits the belt to the lead screw so I changed up some of the geometry. The gearbox is starting to look pretty complicated and dense without the second most complicated part (the CAM). I am holding off coloring everything and pocketing till the very end because it’ll be very satisfying.

Finish up Linear Motion for CVT. Mounted the linear bearing, added the servo, and finalized the linkage so the actual CVT part now works. Now, I have to work on the CAM mechanism.