Drill Motor Transmission Help

We seem to be having problems with our drill motors/transmission. Every time we put together a drive train using the drill motors, we always have one side that doesnt work quite right. When we let it run off of the floor, they both spin fine. But when we put the bot on the ground, only one side would move, and the other side would only move when started slowly. It keeps making the clicking sound. It sounds like the gears keep shifting. I don’t know what the problem might be, but we have experienced this during our summer season, where we built a practice bot.

Please help

there are some good pointers in this thread: http://www.chiefdelphi.com/forums/showthread.php?t=25178

There is another thread that would have told you everything you need to know about this.

We have the same problem. It seems that the spring on the shifter must be looser this year than previous years because it hasn’t been a problem for us before and this year it is happening to both of our drill motors.

Dave lavery’s White Paper on disassembling the drill motors will help you to find out how to get to the spring, and I guess I’ll just quote Ken Leung from the above mentioned thread when he tells us what the problem is and how to fix it. Ken says:

"The way the spring work is the more you turn on the dial toward “drill”, the harder it press on the spring, and the harder the spring press onto the little metal balls under it.

So, one good way to lock the clutch in gear is to take the spring out, and replace with a solid ring the length of spring when compressed the most. Then the metal balls will be flush with the holes, and grab onto the ring gear with little notch completely and prevent it from slipping.

The other way is to take away the dial completely, and the metal balls as well, and tap the hole, and put set screws in instead."

Thanks to all of these helpful folks for the information, and thank you for searching for “Drill Motor Slippage” before you post a new thread next time.

Or you can zip tie it in place…Sometime it will get stuck in between high and low gear. If you do, make sure you’re zip ties in the same direction, or else you robot could be running in circles.

if you’re trying to lock the gear in low, you can just attach the back piece that affixes the motor to the gearbox incorrectly. Thats what we did. Zipties work and if you take the time and can get past the aggravation, you can use the blue rubber bands FIRST provided. it takes at least 4 of them, but they can work.

your problem is a very common one…it seems like the tourqe setting on your gearbox is set wrong…if you spin the top piece of plastic (with the numbers on it) to the drill setting (it looks like a drill bit where the numbers are) that sould solve your problem.

with the standard orintation of the drills the “bit” looking labe should be straight up when the drills are in the FIRST mounts

hope this helps, if not there are quite a few other ideas in the other threads

Thank you for all your help.

After I try it tonight with my team, I’ll let you know how it went.

Thanks again,

[edit] We got the drive train working. All i had to do was turn the clutch to drill. Thanks for helping us out!!![/edit]

We lost a couple of the spring clips that go on the white plastic ring that slides forward and back to select high-low gear. We’re now holding them in with steel hose clamps, which I gather some think is what the broccoli rubber bands were provided for. But our spare transmission is now worthless, since it has no clips. Bosch says they can’t provide replacement clips, that we have to buy the whole transmission @ $51. Anybody solve this another way? Alternatively (and wishfully thinking) anybody have spare clips from ruined transmissions that they’re willing to part with?

Bill Bennett

you can modify the transmission so it works without the spring clips. if you want to lock the tranny in low for instance there is a method that you place an O-ring inside to physically make it imposible to shift the transmission…

check this thread out for ideas http://www.chiefdelphi.com/forums/showthread.php?t=23309&highlight=transmission+ring

We had the same problum at the buckeye regional last year. It is a simple fix, make sure both transmissons are locked in low

I believe this was posted in regards to the 2002 and prior years drill motors. These motors had ball bearings, while ours currently have two metal tabs that sit on the face of the drill motor under the clutch. These two tabs are what the spring presses on.

If you remove the clutch, make sure that you keep, and find a way to retain these two tabs, as the motors run very poorly without them. Last year, we took the clutch off, and made our own mounts that included a pocket milled into them for the tabs to sit in.


epoxy fixes everything…
edit: by that i meen, epoxy the sucker into low gear. with the clutch set to drill it will not be a problem. once it is tehre, epoxy it too. that way, nothing will move on ya

also if your having trouble with the assembly coming apart in the mount, you can epoxy it :yikes: