gearing for torque

[maroon ranger]

Hey there I have a question about a project I am doing in my Technical Math class. We have 7 days to make a speed car or a torque beast out of a put together erector/lego set. Well I chose torque because I have a buch of ricers in my class and we are doing a tractor pull and tug of war and well it's simple to say that I wanna kick there butts!!! Haha, well we are give 10 gears, 2 of them are 75 tooth, 4 are 45 tooth and 4 are 15 tooth. What combo of these gears will give the best torque? I have a 75 connected to an axle with a 15 tooth and then another one like it with the teeth of the 75 meshing with the 15 on 75/15 gear in front of it and then a 45 meshed to the 15 then a 45 by its self then a 15 meshed with that and then a 45 connected to the drive wheels. SO it looks like this, 75/15, 75/15, 45, 45, 15, 45. Should I use the 45 off the motors out put shaft or should I use a 15? What do you think would that be it? Sorry for the brain buster but I think that this will be pretty fun when it gets put together right!! Hahaha thanks in advance.

 

[low_five]

how does the motor attach to this whole thing? does it directly drive an axle or is it a gear?

the last set of 15,45 seems redundant. why not just use the 45 coming off the 75/15, instead of stepping it to the 15 then back the the 45?

 

[maroon ranger]

the motor out put is meshed with the first 75 tooth and I am not sure if I should use the 45 or the 15 tooth gear on the motor out put. And if i did the 45 to 45 at the end then the car would move backwards instead of forwards.

 

[low_five]

smaller gear on the motor will yield more torque.

i just dont understand why the last two gears are on there. what is the point? do you have to use all gears available?

 

[triumphrider-1]

Do you know the output speed (RPM) of the motor?

Approximate motor torque output?

Can you use step shafts?

 

[maroon ranger]

3000 rpm electric motor. And no I don't need all the gears but one of the 45 tooth gears is just placed in there with no axle holding it because if there was an axle through it the axle would hit the 75 tooth before it. I wish I had a picture to show you guys but I don't. But if any of you guys knows gear ratios and can figure out a better way to use the gears to make the most torque that would be awesome!!!

 

[rangerbum]

15 and 45 shouldnt really be needed unless you are required to use all the gears. Sounds like a pretty well-applied TechMath class compared to all the "theoretical" situations we have to deal with. I know what you mean about the ricer state of mind in helena. I think its getting even worse around Billings though. Im in Kalispell Btw.

 

[triumphrider-1]

Here is my suggestion:

For gear meshing, instead of the chain and sporcket systems (shown), the 2wd model's top two shafts will be reverse rotation (opposite the electric motor).

Just did the 4wd model because I thought it would be interesting (does not give best torque multiplication).

 

[maroon ranger]

"rangerbum," I agree with you 100 percent...even though some of these guys are my freinds but they are so annoying when they talk about there car and what not being the best in town when all they have done is exhaust and window tint and maybe even rims and tires. But hey that's cool to see another Montanan on hear for a little while I thought it was just me, hahaha.

 

[maroon ranger]

"triumphrider-1," thanks for the drawering but that is basically the same thing I have. So would this be the most efficient torque combo or are there any other exceptions? By the way...I don't need to use all the gears.

 

[triumphrider-1]

The way I see it that would be the best.

I underdstand you don't need to use them all, but this gets the best multiplication for what you have.

 

[Bryan22]

Kinda funny triumph, your picture reminds me of the diagram inside of a drill press.

 

[triumphrider-1]

Kinda funny triumph, your picture reminds me of the diagram inside of a drill press.

Yeha, it kind of does, doens't it.

 

[rangerbum]

"rangerbum," I agree with you 100 percent...even though some of these guys are my freinds but they are so annoying when they talk about there car and what not being the best in town when all they have done is exhaust and window tint and maybe even rims and tires. But hey that's cool to see another Montanan on hear for a little while I thought it was just me, hahaha.

EVERYBODY'S car is the best in town haha. There are alot more Montanans on here than I thought too, they just dont include their location for some reason

 

[maroon ranger]

O.K. guys so I did the whole test about two weeks ago and came up with like a 220:1 gear ratio and won the compitition! We did a tractor pull and then tested the max pull in pounds using a fish scale and I beat eveyone by more than double there weight and distance pulled!!! And I also chaned up the gears and got second in the drag race, hahahahaha!!!! Well thanks for the help everyone I really appreciate it!!!