Image Discuss: Plan View of 27's Transmissions

[PMGRACER]

Hey thanks for the compliments guys! We did work hard on the system we have now. This is the 3rd generation of this design. We have reverse engineered the Bosch trans thouroughly. We feel it is an efficient design. Meaning we get the benefit of a high differential of ratio in a small space. The Bosch design seems to be quite robust. I'm sure the engineers at bosch never thought their simple design could take so much abuse!

We do use some of the gears from a stock Bosch trans, but everything else is scratch built. The stock output shaft used dowel pins for the final stage gears, we replaced them with .125 shoulder bolts. Obviously we scrapped the clutch. The next gen will use Timken Tappered roller bearings to deal with some of the radial loading we can't get rid of. The slider ring, as stated earlier, is a custom piece. Also gone is the plastic housing, with the wimpy teeth in the front which strip just by breathing wrong.

The Drill and Atwood motors are mounted in the same orientation to eliminate the torque steer you get when the motors run in oppisite directions. We just rotate the output shaft 180 degrees. If you look closely at the back of the units, you'll notice the output shaft sticks out. I call it the PTO shaft, becase there is a .187 female hex EDM burned through the shaft, so we could use the output to power other systems.

Shifting is very smooth. As I said earlier, the slider ring is suspended between 3 pins which kept it square to the shaft. The face looks like a 1 5/8" nut and the bore of the housing has a 1.652" "socket" milled into it. You need the .025 clearance for it to shift smoothly. However, there is no lash. Once engagerd there is no rattling noise.

BDuggan and his brother IDuggan can have the units out of the robot and torn down in about 10 minutes. With the Hex coupling, you don't have to tear apart the drivetrain to pull the trans. Once out of the 'Bot, remove 6 Allen bolts and the planetary section separtates from the power section.
PMGRACER