Running Banebots Transmission in Direct Drive

[Marcel]

Does anyone think that running the Banesbot Transmission in direct drive is a bad idea?

[Jonathan Norris]

Most likely, that means you are only putting a 12:1 reduction on the CIM motor... which depending on what size wheels you are using could be a bit fast. Do the the calculations with the motor specs from here and figure out how fast you will be running. Then we can give you a good idea if its too fast, usually a fast FIRST bot is 10 ft/, and a slow bot would be 3-4 ft/s. All depends on how you are playing the game.

edit: I would worry about putting that much load on the shafts of the gearbox's, i would highly recommend putting the bearing blocks on the other end of the shafts if you are direct driving it.

[Daniel_LaFleur]

Running a CIM into the 12:1 banebots transmission with a 6" kitbot wheel gives you a 7.6 Feet/sec speed.

Going into an 8" wheel increases that speed to 11 feet/sec.

[Jeff 801]

Originally Posted by Daniel_LaFleur

Running a CIM into the 12:1 banebots transmission with a 6" kitbot wheel gives you a 7.6 Feet/sec speed.

Going into an 8" wheel increases that speed to 11 feet/sec.

with the KOP 6" wheel it turns at 11 f/s and that sounds right if you've seen one run

[jts]

It wouldn't necessarily be a bad idea if you used small enough wheels and supported the shaft. You can also purchase the gear change kit that would make it 16:1 instead of 12:1.

[Justin M.]

If you up the gear ratio, and used four gearboxes on four wheels, it would be possible. Make sure you connect the wheels together with a chain to transfer even torque to the front or back of the bot (in the event of a pushing match). You'd also need to make or order a hub for whatever wheel you are using, as well as a pillow block to support the shaft.

Now - would I recommend it? Not really. Gear it down with chains, and if those are too heavy use belts and pullys. If space is an issue then use some type of slim-2nd stage output gearbox with the outputting shaft running directly to the wheels.

[Jared Russell]

CIM free RPM = 5500-5750 (depending on which individual motor you test)

Reduction = 12:1

Output Shaft RPM = 5500-5750/12 = 458-479

Speed with a 6" wheel = 458-479 RPM / (60 sec/min) * (2*pi*3") / (12 in/ft) = 12-12.5fps

Speed with a 8" wheel = 458-479 RPM / (60 sec/min) * (2*pi*4") / (12 in/ft) = 16-17fps

Keep in mind that those are numbers assuming FREE SPINNING RPM. In reality, we find the loss to be about 25%, so with a 6" wheel you can expect a speed of about 9-10 fps and the speed with an 8" wheel to be about 12-13 fps.