Ideas on a motor coupling?

Have you considered dispensing with the gear and its shaft and making one to suit you? It would simplify matters.

Tom

That motor appears to be identical to one that a friend of my son used in a robot he built for his senior project last spring. We made a new shaft. As I recall, the output shaft was coupled to the wormwheel in the gearbox by a detented overload device. The sheet metal cover bears on the end of the shaft inside the gearbox and holds the detents together.

I don't remember exactly, but I think the new shaft was just a piece of round stock with a welded-on arm that engaged the detent.

Ned Simmons

Set screws should work OK if there isn't any axial moment.

Another possibility: make the piece you describe, but with an axial hole thru to the bore. Place on gear, pour in some molten Cerrosafe

-- a metal that melts at between 158 and 190F -- not even boiling. Then pin the Cerrosafe slug.

It looks to me like you have almost got it. If you were to take a Dremel with a cutoff wheel or a similar device and cut into the gear where your setscrews would ride, you can keep them from sliding off. And, if you were to make a few more random cuts and work some waxed paper under the gear (for obvious reasons), you could then bed your coupler in with some JB Weld or something similar and it should be very solid.

Jerry

Learn or produce ? Making a gear is fun to learn , but producing needs to get a handful of small BB's and make flat belt ( crown one , the other is flat ) and get a very efficient gearing down .

If the speed drops too much , use chain drive as in a tiny hand held band saw . Chain is not hi friction and can take a large over load . 150 HP Honda motorcycles use it well . If you have space problems , then you'll have to use gears and hydraulics !

BTW whats the ID of spindle bearings on HF 7 by 10 Lathe ?

______________________________________________ Tom wrote:

Whatever...

Your idea shouls work pretty well. Only thing I'd do different is clean up the gear REAL well and mask the back plate, then fill the teeth with JB Weld or equivalent before pushing the adapter on.

Wow that was a quick response. To sum up my options as I understand them:

I actually was thinking of the low-melting point "fixturing alloy" material. I may try to find a local supplier. For those of you who said it looks familiar, it is the Window motor out of the ~2004 FIRST robotics competition Kit of Parts.

I haven't actually tried opening the motor/gearbox, so I don't know what exactly the other side of the shaft looks like. That detent-overload thing sounds a lot like some of the other motors I have dealt with (read: cursed/smashed in frustration) so I'm not sure if I really feel like going that route. Also, my welding skills are sketchy at best.

Also sounds like JB Weld is going to be a good idea. I think I'll go with the current design, but notch the gear for the setscrews, and then drill the bore all the way through. That way I can inject the JB Weld from the end, rather than trying to put it in the gear area and then trying to squish it on and tighten the setscrews.

Thanks a lot for all of the suggestions, WW88

Apparently you ignored the request to limit your jpgs to 50KB or less.

I was shocked, shocked to find that I wasn't familiar with that verb.

I had to look it up:

You never saw "Easy Rider"?

Best regards, Spehro Pefhany

It will fall off as soon as you have the slightest missalignment of the axes or a rotating side-load. Can you drill through the CL of the gear and have a screw to pull your coupling onto the gear?

Nick

On Sun, 12 Nov 2006 22:45:06 -0500, with neither quill nor qualm, Spehro Pefhany quickly quoth:

You poor, sheltered dear.

Ah, shades of another lifetime...

Yee Haw!

-- Chipmunks roasting on an open fire...

"woodworker88" wrote in news: snipped-for-privacy@h54g2000cwb.googlegroups.com:

Take advantage of the 3 threaded holes on the housing and make a plate retainer. Put a groove into the OD of your shaft, make a plate that hits the 3 bolt holes and has a loose-fit U that will fit inot the groove on the shaft. Since the rotational speed of this motor will be slow, a dab of lithium grease should be more than sufficient to keep things from wearing very fast. This will prevent axial movement of the shaft.

I was going to suggest that he compress those pix. a bit also. :-) ...lew...

Hey! Thats a great idea. Why couldn't I have thought of that. :-) ...lew...

You seem to be ignoring the principle that motor couplings must incorporate flexibility when coupling to a rigid mechanism.