What Motors Should I Use?

[Cory]

Originally posted by trail66
team 166 used a 2 speed shift on the fly x-mission low was 4ft/s and high was 9ft/s. we used the CIM motor's. the major reason we used these motor's are as follow's.

reliable
simple no gear box's
easy mounting
spur gear's require only minimal rework to mount to output shaft.

we found it would require alot more machined parts to mount the drill motors and gear box's then simply drilling two holes to support the CIM motor.

Youre still going to need a gearbox, unless you are directly driving the wheels, which would just be stupid, and you didnt do. Mounting the drills takes exactly zero parts. The included mounts arent the best, but if you use em right, they work fine.

Cory

[dddriveman]

I believe that I am going to try to use the same type of setup for our drivetran again using the drill motors and the bosch gearbox. Now that I know about the left handed screw that solves 75% of our drivetran problems. I am going to custom fabricate our motor mounts tough, and instead of running the wheels straight from the gearbox, I plan on mount the wheel with pillowblocks and then using a chain drive. I believe doing this way will solve the problum of the breaking of the motor mounts when the driveshaft gets bound up. This setup will also reduce the stress on the motor and gears by taking the force of the wheels off of them. If any one has anay suggestions on how to do this , or if anyone sees any major flaw with this please tell me.

[Cory]

We did exactly what youre talking about this year, last year, and the year before that. We made motor mounts out of Delrin this year, and aluminum last year. Just hold the front part of the transmission, and the motor itself. When you make mounts, be sure to make it so that the motor cannot rotate no matter what. This year, we made a little bracket that hits against the front of the motor where the clutch belongs. It pushed against a small square raised protion of the transmission, and prevented it from rotating.

If you havent already, lose the clutch, it isnt worth keeping. If you look at the fron of the transmission, with the clutch off, on either side of the shaft is a little metal tab with a spring on it. Make sure that your mount keeps these from falling out, or the motor doesnt run very well, in our experience.

We used some pretty net couplers that work very well. Think of the dogs in 45's, and other transmissions, except with two, longer prongs. These connect together, with a rubber spider (I think thats what its called) in the center. This allows the motor, and/or shaft to not be perfectly aligned, and still run well. We just tapped one of these for whatever size threads onto the output shaft of the drill motor, and then pressed the other one onto the shaft. I think it was secured with pins, but I don't remember.

If you want to save a fairly decent amount of weight,make it so that you are rotating the wheels and not the shaft. This allows you to use only four pillowblocks on the entire drive system. We got away with using bushings too, instead of bearings. You can fabricate your own pillowblocks without bearings, which you can use to mount the wheels in, and keeps the whole thing relatively light. I wont go into the whole #25 vs #35 chain. Choose whatever makes you more comfortable.

We found that for a relatively low speed (3-4 FPS) we could gear the motors down approximately 4.14:1 with a 11t sprocket on the drive shaft, and a 45t sprocket on the wheel, with the drill transmission in low. This gives a lot of torque, but you probably want a bit more speed unless you are going to shift the drill's with a servo, or another way. If you want information on that, feel free to PM me. We have done this for two years, and would like to think that we have it perfected (almost)

Almost forgot. If youre going to not shift, make sure you secure the transmission in either low or high gear. You can find whitepapers here on how to make rings to lock it in place.

If you have any more questions on what we did, or in general, feel free to PM me and I'll try to help ya out.

Cory

[Veselin Kolev]

One piece of advice, if you're going to pin the drill motor output instead of using the left hand screw, make sure the machinist that does it has carbide or diamond tipped bits, because the shaft is hardended steel. We tried, but all we got was a worn out drill bit and a hole going nowhere in the coupler. For us, it wasn't the left hand screw getting worn out, we broke the drill motor gearbox a lot. And every time we replaced the left hand screw because we were worried of stripping it.

If you have the time to, try to design a tranny without using the drill motor's gearbox. It saves space, weight, and improves the efficiency of the motors. Also, you don't have to worry about left handed screws, flimsy plastic mounting brackets, broken gearboxes, and shifting locks on the gearbox. It also looks really cool.

[sanddrag]

I am a proud defender of the 2003 drill motor and drill motor accessories. I've seen so much complaining of problems and beakage - most of which I believe is due to improper installation or modification. Team 696 has had no problems whatsoever with them nor their accessories after two regionals, an off season, an exhibition, and a couple brief demonstrations.

[Veselin Kolev]

Originally posted by sanddrag
I've seen so much complaining of problems and beakage - most of which I believe is due to improper installation or modification.

True, it is very possible to damage the gearbox through inproper installation, but I doubt our team did that. We used the provided plastic mount brackets and coupler. It's pretty hard to install it the wrong way. Plus we had the shifter secured very well into low gear. But the way we broke it isn't explained by this. We opened up the broken ones and found the gears to be completly stripped out. This can only be caused by a pre-existing weakness in the gearbox. It seems that you can only put so much power for so long into it before it starts to rip itself apart.

Other than that, the motor is great. I tend to like it without its gearbox though.