Planetary Wobble Teeth Gear

pinshape

Summary A novel planetary or epicyclic gear design features a unique tooth shape that improves precision and stress distribution, inspired by the smooth edges of bones. The gear's parameters can be easily modified by adjusting the tooth dimensions on the sun or planetary wheel, tooth width, height, or number of planets. Currently, the planet holes are set up for regular skate bearings, but design testing is still pending. 20140309 - Update 1: I corrected a misalignment issue in the gears and am waiting to upload the next version until I resolve a misaligned polygon between the tooth valley and top. 20140309 - Update 2: The new model is online, with the misaligned polygon fixed temporarily. Suggestions are welcome for addressing this issue other than adding 0.01mm to the tooth radius. 20140311 - Update 3: After failing to compile in sufficient resolution, I'm working on a solution that generates dxf files and extrudes them in 3D instead of compiling separate gears. 20140313 - Update 4: The job is finally done using about 130 minutes and 5GB of RAM. Saving as stl takes quite a while. 20140315 - Update 5: I noticed and fixed a bug in planet rotation calculation for placement, center hole calculation, and necessary changes in orientation when changing the number of planets. 20140317 - Update 6: Unfortunately, the built tolerance was too high for the sun gear. Further work needs to be done on reducing the tolerance. 20140530 - Update 7: I experimented with the cutting edge offset function of the experimental openscad build but found that the tolerance must be calculated based on the gear radius. Further investigation is needed, and printing the gears one at a time might improve the fit. Instructions To compile, simply run create.sh. The script generates .dxf files that will later be extruded and saved as .stl. The parameters are mainly stored in wobblegear.scad, which also provides the 2D gear function. The design can be printed without support. Currently, the sun center hole is dimensioned for an M5 nut/counternut/bolt, while the planets are designed for eight regular skate bearings with a 22x7.7mm diameter and 5mm distance piece. The image shows only the 2D view of the gears without holes due to rendering time. The design is currently set up with 20:40:100 teeth, resulting in a 6:1 ratio if the annular wheel is fixed. Please note that: * Gear radius is calculated based on tooth dimension and quantity. * Changing tooth quantity or dimension may require adjusting gear alignments in multiples of alpha. * I'm testing with increased tolerance to 0.4mm because 0.2mm was too low.