Gear boxes

hi all

what apart from gears do i need for gear boxes?

using mod 1 gears

alex

Depends what you hoe you want to put it together.

Cylons gear box has a spur gear on the motor (8mm shaft with a grub screw through the gear and shaft to hold it in place)

The other gear is screwed directly onto a wheel and runs on a 12mm stainless steel axle. This sits inside a plastic 12mm mount.

What I found was that it is good to drill the holes by sticking the gears in a lathe and you will need some tough drill bits as normal HSS will burn out.

Having driven it a bit it keeps veering off to the right but we (Well Froggy actually) came to the conclusion that this is probably to do with the fact that it needs a couple of washers either side of the gears to hold them in place.

We used the 150w gold motors, but should be the same for any of them.

I also found it ran better and took up less space if you cut the boss off the back and smoothed it over with the lathe. It also means youre not fouling the motor in anyway with the boss.

Andy

An axle and at least 1 plate to get everything together.

Depends what you plan, single or multiple stage reductions. Like Mario says, dont forget bearings in the plate if you have the shaft going round with the gear. Ideally each end of the shaft wants to be supported with a plate and bearings.

Yep, we did away with the bearings because its a fixed axle and it runs ok for the 20seconds it normally lasts in a fight.

Andy

As your looking at a 2 stage gearbox it will depend. Firstly you need 3 bearings inside the geabox if your output shaft is inline or near the input (you will want a support with bearing the other side of the wheel) or if the output axle can get to the back plate then 4 bearings in the gearbox with no support for the other side of the wheel, 2 aluminium plates (if its not enclosed and milled from a billet), 2 axles - size depending on bore of the gears.

What weight are all of your gearboxes? How reliable are the gearboxes as compared to a cordless drill?

The gearboxes in the Hannibalitos never failed.(except the one time Little Hitter smashed the magnet in one motor- but that gearbox is still in use)

Weight, due the heavy motors, we can do it in a bit less than 1500 grams with 100mm wheels.

Hard to beat the gearbox of a cordless drill on price, weight and availability. Reliable too.

I run 15:1 ratio 2-stage gearboxs with 4wd, 75mm wheels and 2 astros for about 1kg in total, 500g a side. You wont get lighter than that!

Grant, John has a point on pricetag.

It doesnt need to be as expensive as mine though - a little bit of creativity and time is all it takes, maybe not quite that light, but close.

creativity and time

http://www.wa4dsy.net/robot/trisector-robothttp://www.wa4dsy.net/robot/trisector-robot

ALL Dales bots are worth a look.

Some nice engineering going on there, i like the damper flipper.. i pressume the motor just drives the arm back, compressing the air in the dampers, then the linkage is un latched releasing the power. pretty cool.

I have a question about torque...

Exactly how much is a oz-in..??

I read for example on Robot Marketplace that a Ampflow A28-400
motor has 3720 oz-in torque, but how many Nm is that..??

3 720 ounce inch = 26.268 972 82 newton meter, approximately :lol:

Best on-line conversion site I've found... http://www.onlineconversion.com/torque.htm