California Drive

[Xifilzer]

Currently my team builds robots with a 6 wheel drivetrain (pneumatic or AM rubber wheels + omnis), and we just completed our 3rd season. This past season we built our own chassis (as opposed to a kitbot) and housed the wheels in 1" x 3" tubing on one side, and 1/8"plate on the other, and drove 8" pneumatic wheels using sprockets and chain. But, with our side plates taken off, our robot was stanced, and all the wheels were angled. We have accurately drill pressed all our holes, and house the shafts of the wheels through both faces of the tube. Is there a different means to go about constructing a West Coast Drive? How would you prevent your wheels from angling under load?

Thanks in advance,
Xifilzer

[Mike Marandola]

Originally Posted by Xifilzer

Currently my team builds robots with a 6 wheel drivetrain (pneumatic or AM rubber wheels + omnis), and we just completed our 3rd season. This past season we built our own chassis (as opposed to a kitbot) and housed the wheels in 1" x 3" tubing on one side, and 1/8"plate on the other, and drove 8" pneumatic wheels using sprockets and chain. But, with our side plates taken off, our robot was stanced, and all the wheels were angled. We have accurately drill pressed all our holes, and house the shafts of the wheels through both faces of the tube. Is there a different means to go about constructing a West Coast Drive? How would you prevent your wheels from angling under load?

Thanks in advance,
Xifilzer

Might be a dumb question, but are there bearings in BOTH faces of the box tubing? How much space is between the outside of the the box tubing and the wheel?

[indieFan]

Originally Posted by Xifilzer

, and all the wheels were angled. We have accurately drill pressed all our holes,

How did you drill the holes? A drill press does not have the same ability to drill straight like a mill. I would suggest drilling the first wall, then use a transfer punch to get the second wall in the same location. For anything over 1/4" diameter, start with the hole in the first wall being the largest size transfer punch available, transfer it, then drill the larger hole.

[JesseK]

Originally Posted by Travis Covington

The elegance and simplicity of the design, however, was something that had been done by team 60 for many years before the prototype 6WD drive train that was used at Cal Games in the Fall of 2003 and the collaboration between 254 and 60 that occured in 2004 and brought about the now well known 6WD West Coast Drive..

Do photos of the original still exist?

[Xifilzer]

Originally Posted by indieFan

How did you drill the holes? A drill press does not have the same ability to drill straight like a mill. I would suggest drilling the first wall, then use a transfer punch to get the second wall in the same location. For anything over 1/4" diameter, start with the hole in the first wall being the largest size transfer punch available, transfer it, then drill the larger hole.

Originally Posted by Mike Marandola

Might be a dumb question, but are there bearings in BOTH faces of the box tubing? How much space is between the outside of the the box tubing and the wheel?

Sorry a correction to my original post, we used pillow blocks mounted to the underside of 1x3 tubing instead of running the shaft through the tube.

http://www.mcmaster.com/#5913k61/=1285fnp


Looking from an aerial perspective, going from the outer side of the robot inward, this was our setup:

shaft collar, flange bearing in a 1/8"side plate, two 1/8" thrust washers, 8"pneumatic wheel bolted to a keyhub, a sprocket for 25 chain, two thrust washers, pillow block, shaft collar (for spacing), a sprocket for 35 chain, shaft collar.

This sums up to around 3.25" between the pillow block and sideplate, and 1.5" from the pillow block to the tip of the shaft on the inside. I'll try and take a picture tomorrow.

Thinking about it more, i think the pillow block may have been the source of our problems, since it allowed the shaft to pivot, instead of binding in place had we simply gone straight through the tube (with bearings XD).