Differential (strong, all printed parts, FDM optimized)

Strong and compact differential optimized for FDM 3D printing. Full print-in-place is theoretically possible, but I recommend printing part-by part.

So far I haven't been able to break or strip any of the gears going full force by hand (Nylon and CF-nylon printed gears), so I expect it to compare with or beat any commercially available differentials of the same size

The differential itself requires only two screws to hold together the gear cage. To get any use out of it you need to screw in adapters similar to the “output shaft adapter example”. You can use a set of 4 screws with a 10mm threaded section, but I would recommend the output shaft couplers be held in place by 12-15mm of thread. Screws are self-tapping widely spaced thread screws as the ones universally used in all plastic products. You will need 2 more screws to hold the motor bracket and three more to hold down the casing clamped to whatever chasis you're making. That's 9 screws in total. All screws have outter-most diameter of the threaded section of 2.5-2.7mm

The sun gears are 4 of the same model, however the right and left axle gears have slightly different shaft lengths. The upper and lower half of the casing are the same part but mirrored.

The f360 project is a dirty product of self training, so only use it for body derives/exports and dimension references.

I picked spur gear internals, as it is far more straight-forward to print and assemble than the bevel gear classics in youtube animations. Bevel gear differentials are a topological hell to print in parts and could never be as compact and strong.

The motor gear is meant for 6mm shafts and the motor bracket example is meant for paper-feed drive printer motors to be held in place with some gluing. You can sketch and build your own bracket or bend the one I have provided to fit your needs.  

To make a custom bracket you just need the screw hole spacing and the gear opening sizes as listed below.

Dimensions:

-motor shaft diameter (goes in the hole of the motor gear): 6mm

-outer casing outer diameter: 32mm

-bevel gears angle 40.7 deg

-width without the output shaft couplers: 35.75mm

-motor bracket screw hole center to center: 28mm

- casing holes form a triangle. the two rear holes are spaced 16mm. The hole on the motor side is 55.879mm and 59.887mm away from the two holes (Euclidean distance). Or you can draw a rectangle between the two 2nd closest to each-other holes with dimensions of 55.499mmx6.5mm

-screws: 9 in total, 10-15mm threaded section, 2.7mm outer-most diameter of the threads

Print orientations:
casing pieces-deliberately weird angle with tree supports and the concave part pointing away from the heatbed.

cage gear- the top of the gear cone sits flat on the heatbed

all other gears -printed with the axis of rotation up along the Z axis

cage gear cap- bolt holes facing the heatbed; gear bearing holes pointing towards the printer nozzle.

output shaft adapter- the axis of rotation is parallel to the x or y axis