Large Mecanum Wheels by lwr20

Last crawled date: 3 years, 1 month ago

90mm (diameter) x 22mm (width) Mecanum wheels, as used on our robot "Tigerbot" in PiWars 2018.
PiWars has a width limit of 225mm, and the motor/encoder/gearboxes (Pololu 25mm gearmotors) used up most of it. It was impossible to find commercially available mecanum wheels narrow enough to fit on the robot (and they cost a fortune), so we ended up designing our own.
The Rollers were printed in RigidInk TPU. I printed them vertically with a brim and used the sequential printing option (i.e. finish a whole roller before starting the next) to avoid stringing between the rollers. You need to allow lots of space between them for the print head to fit between them - I got 16 at a time on my Prusa print bed.
The Frames are simple PLA. The two halves bolt together with M3 nuts/bolts. There are 3 bolt holes for mounting the wheels onto a 25mm cylindrical hub (not included in these files) which attached to the motor with a grub screw. The rollers are attached to the frames using 26mm dressmaker's pins (I found it helped to drill out the holes in the frames with a pin drill first). The pins are held in place with a dab of epoxy on the head - but check that the roller rolls freely before you do that!
For a 4 wheeled robot, you will need 2 sets of the 2 wheels in this package - a pair of clockwise wheels and a pair of anti-clockwise wheels. You mount them on the robot so that the pairs of the same wheels are on diagonally opposite sides.