modified toughbox

[gorrilla]

has anyone modified the gear ratios to make them faster?
if so what did you do?

because team 1557 was thinking about new trains and we wanted to change the gear ratios from 12-1 to something lower

[MrForbes]

We did this, by removing the second stage of gear reduction. It requires drilling some holes in the aluminum plate to clear the ends of the motor shafts, and playing with the end play spacing of the large gear, plus relocating the gear tooth sensors (if you are using them). For 4" wheels we used a 1:2 sprocket reduction ratio (12 tooth on the transmission, 24 on the wheels).

[EricVicenti]

Originally Posted by gorrilla

has anyone modified the gear ratios to make them faster?
if so what did you do?

because team 1557 was thinking about new trains and we wanted to change the gear ratios from 12-1 to something lower

Yes, we used a few gears from the toughbox and a few gears from the AM supershifters (both of which we had lying around, you can buy the individual gears online). We then simply CNC'd new front and back plates for use of the new gears to press the front and back plates into. Like the toughboxes, we used lexan for the motor side, and 1/4" aluminum for the mounting/output side.

The ultimate ratio was around 7.8:1, much higher than the toughboxes, and slightly higher than the high speed of the supershifters. They have worked perfectly without a hitch. They took an evening to design, 2 days or so to CNC 4 perfect plates, and another day to assemble and break in.

Do you have any specific questions?

[gorrilla]

well we were thinking about changing the gear in the back which is connected to the drive sprocket with a smaller one to bring the reduction to about 2-1 or maybe even 1-1 and then putting smaller sprokets on the wheels because this year we were very slow compared to the other teams at only 9-10 fps because our am 2 speeds were stuck in low gear wich sucked and we couldent put it in high and leave it or the chains would slip

[gorrilla]

update)(

weve done it we removed the second stage and given our gearbox a 1-3 (increase)?? by doing the math we have founs that one on each side with 2 cims would give us 23+fps or more depending on the sprockets on the wheels

[billbo911]

I do know for a fact the Team 1147 did exactly this. From the reports I had, it was really fast!

It did take some rework of the Toughbox to get the gears lined up, but it was worth it. I believe the final gear ration is 6.38:1.

I'll see if I can get one of the students to post up on how they did it and how well it worked.

[kramarczyk]

Originally Posted by gorrilla

update)(

weve done it we removed the second stage and given our gearbox a 1-3 (increase)?? by doing the math we have founs that one on each side with 2 cims would give us 23+fps or more depending on the sprockets on the wheels

How's the turning?

[gorrilla]

i havent tested it on the robot yet but as soon as i get a 6-wheel drive going i will

it will probobly be done sometime this month or next depending on how much time we work and what not


p.s. the 23+ fps mark was the speed one wheel would turn if we had to cims on each side so with 4 to 6 wheels and the correct sprocket size we should be around 20 to 26 fps...