How to fix the worm gear issue!!

[Yawzer]

An old bike racing trick (pre-sealed bearings) - works great on all kinds of gears as long as they are metal.

Mix 1/2 rubbing compound with 1/2 grease, generously grease your gears with this mixture & run for 10 - 15 min. with a drill. This will polish the gears to the point of having almost no friction. Take apart & clean well. Re-lube with gear jelly - you will be amazed at how smooth things will be.

 

[TattooKenny]

This would also remove materiel? Any time you polish something you take away part of it. In a lot of things polishing can weaken the materiel that gets polished. I would think that if you polished plastic like a worm gear that it would make it thinner and weaker? I see that you said on medal gears. Have you done this on the Losi? If so pict's please....

 

[The Real Dogman]

Yeah!! Pics or it didn't happen..













lol

Sorry couldn't resist, I am ill

 

[Harley]

This would also remove materiel? Any time you polish something you take away part of it. In a lot of things polishing can weaken the materiel that gets polished. I would think that if you polished plastic like a worm gear that it would make it thinner and weaker? I see that you said on medal gears. Have you done this on the Losi? If so pict's please....

Are you saying the worm gears are plastic? I don't get how this makes any sense :|

 

[Rocksmith Eng.]

Now this isnt a bad idea, but................
I am not sure what kind of heat treatment or case hardening these gears have undergone.

In the case of heat treating , the process hardens all the material. Is usually a process of heating and cooling the metal.

In case hardening, you heat the part and submerge in somekind of powder which actually bonds with the part. This treats the outer few thousands of an inch of material. The inner material stays at a softer state.

If the gears are case hardened, and you polish them in this method you would be exposing the softer inner material and actually creating more friction

Just my .02
and this is by means

 

[TattooKenny]

Are you saying the worm gears are plastic? I don't get how this makes any sense :|

No! Just saying that anytime you polish anything you will remove material. I was only saying that if it were done on plastic it would be that much worse. Wouldn't make since to do plastic, just saying. I used to do a lot of polishing for CompuCar. It doesn't take much to completely screw up a part by polishing to much. I can't say for gears but in the 1:1 world a polished part holds more heat than un-polished.

 

[microgoat]

I haven't seen one apart yet (other than Freq's well-lubed pics), so here's a question about the worm gears:

Is the driven gear straight-cut, or are the teeth angled to match the worm's pitch (aka helical-cut)? A wide, straight-cut gear would seem (to me anyway) to want to bind just a little. Perhaps a narrow gear, or twisting the teeth a bit, could help with the heat issues.

I know it'd be a bitch to manufacture a helical gear, but it seems this might be the answer? Or perhaps a rounded profile across the teeth to reduce the interference at the ends where there's non-linear contact?

Pardon my ignorance. I'm no engineer, but there has to be a solution for worm-gear heat buildup.

EDIT: It seems all the worm gears I was able to Google are helical-cut. Why not the Losi?
EDIT again: Here's a GIF showing what I believe to be a proper worm-gear setup:

 

[SACCO]

The amnt of material removed from polishing would be less than running a few packs under comp loads, right?

 

[SACCO]

This would also remove materiel? Any time you polish something you take away part of it. In a lot of things polishing can weaken the materiel that gets polished. I would think that if you polished plastic like a worm gear that it would make it thinner and weaker? I see that you said on medal gears. Have you done this on the Losi? If so pict's please....

I been polishing my knob for years and didnt know!

 

[Harley]

I been polishing my knob for years and didnt know!

Watch it, every time you polish it it will get smaller :shock:

 

[Harley]

I haven't seen one apart yet (other than Freq's well-lubed pics), so here's a question about the worm gears:

Is the driven gear straight-cut, or are the teeth angled to match the worm's pitch (aka helical-cut)? A wide, straight-cut gear would seem (to me anyway) to want to bind just a little. Perhaps a narrow gear, or twisting the teeth a bit, could help with the heat issues.

I know it'd be a bitch to manufacture a helical gear, but it seems this might be the answer? Or perhaps a rounded profile across the teeth to reduce the interference at the ends where there's non-linear contact?

Pardon my ignorance. I'm no engineer, but there has to be a solution for worm-gear heat buildup.

EDIT: It seems all the worm gears I was able to Google are helical-cut. Why not the Losi?
EDIT again: Here's a GIF showing what I believe to be a proper worm-gear setup:

Very good points, sounds like an aftermarket upgrade huh?

 

[gunnar]

The ring gear doesn't have to be helical cut, as long as there is enough room between the teeth for the worm's helical cut tooth to fit, it will work. It's just that the worm system is not as efficient at transmitting power, plus the thrust forces applied to the worm don't help either. The helical cut ring gear makes for a tighter fit, but what might happen is the straight cut ring gear might get sloppy/loose faster than a helical cut one. Just needs high pressure/high heat grease, heat shouldn't be too much of an issue.

 

[Rocksmith Eng.]

Has anyone tore the cover off the bearing that's on the worm gear?
I think part of the prob might be with the radial type bearing on it. When I get home tonight I plan on replacing that
Will replace with a acer ceramic to see if the axle improves. Have calls
Pllaced round the world for angular contact bearings. Should know today.

 

[husky385]

Have calls
Pllaced round the world for angular contact bearings. Should know today.

I really hope you can find these types of bearings small enough for the rc applications

It's just that the worm system is not as efficient at transmitting power, plus the thrust forces applied to the worm don't help either.

I think a thrust bearing could be used if no one can find a tapered type bearings. If you used a thrust bearing between the worm gear and the radial bearing, you would have to transfer the the thrust through the outer race of the radial bearing. If you put the radial bearing between the the worm and thrust bearing, you would have to transfer the thrust through the inner race of the radial bearing. I don't know which one would be easier to do. I believe it would work though.
Kevin

 

[moes670]

Watching this thread. I run Rock Force axles and they are the same way just one radial bearing on each side of the worm. I think they are a bit bigger at 6x12x4 but just plain bearings. I agree that a bearing capable of axial loads would be better. So I will keep tabs on this thread.

They seam to work fine I have not had any issues bearings wise. The most problems have been because of lack of lube. Seems that with time the grease slings off of the gears to the sides of the housings and you r gears get dry again. Looks like on the Losi axles there is alot less dead space so may not be as much as an issue. One thing I did was drill and tap a 3mm hole in the cases so I can squirt in some grease from time to time. That maybe an option for the Losi axles as well.

 

[husky385]

One thing I did was drill and tap a 3mm hole in the cases so I can squirt in some grease from time to time. That maybe an option for the Losi axles as well.

Very nice tip "thanks"
Kevin

 

[moes670]

Opps I forgot to mention drill and tap One thing to be careful of is make sure you have clearance on the inside at the spot you are drilling:mrgreen:

The nipple on the tube of losi smart diff grease or the high pressure black grease is small enough to squirt the grease through a 3mm hole.

 

[husky385]

Opps I forgot to mention drill and tap One thing to be careful of is make sure you have clearance on the inside at the spot you are drilling:mrgreen:

The nipple on the tube of losi smart diff grease or the high pressure black grease is small enough to squirt the grease through a 3mm hole.

To bad some one hasn't came up with working scale grease guns and fittings.:shock::mrgreen:
Kevin


OOps of topic.

 

[moes670]

To bad some one hasn't came up with working scale grease guns and fittings.:shock::mrgreen:
Kevin


OOps of topic.

Nice!:mrgreen:

 

[dkf]

Now this isnt a bad idea, but................
I am not sure what kind of heat treatment or case hardening these gears have undergone.

In the case of heat treating , the process hardens all the material. Is usually a process of heating and cooling the metal.

In case hardening, you heat the part and submerge in somekind of powder which actually bonds with the part. This treats the outer few thousands of an inch of material. The inner material stays at a softer state.

If the gears are case hardened, and you polish them in this method you would be exposing the softer inner material and actually creating more friction

Just my .02
and this is by means

Case hardening usually has a case depth of .020" or .060". I doubt they are case hardened because the case hardening preocess is usually more expensive and time consuming than a typical through hardening operation with either a higher carbon steel or a tool steel.

I do not see how you are going to take any amount of material off using the method described. It will just knock down some of the burs and help remove some of the tooling mark ridges. I've spent time lapping with a hone and purpose made clover compound and it can take a bit of lapping to remove material.

Pardon my ignorance. I'm no engineer, but there has to be a solution for worm-gear heat buildup.

The worm setup is the most inefficiant gear setup to use inside a gearbox. The more the reduction the more efficiency is lost and the more heat is produced. You can do some searches about industrial gear reductions, I am shure you'll find some good info.