Hypoid
 

Here is a picture of a hypoid gear. It is used on an automotive painting robot that my company manufactures.

Re: Worm Gear Gearbox
 

I'm going to have to strongly disagree about efficiency not being an issue.

Even with your research, which I won't refute, 40% losses in a single stage of a gear set is still quite large compared to the 10%-15% losses over an entire drive train with spur gears and chain.

It should be noted that Adam's article did cite a 97% efficiency for a multiple stage gear train using worm gears, which I found to be quite impressive. (Costs? Yikes! :))

Worm gears have their place, but I would strongly discourage their use on a drive train if you're just looking to reduce your gear ratio. I'd definitely like to see justification addresing the losses, which we can all admit are several times larger than spur gears.

(See Paul's link for an appropriate application.)

Matt

Re: Worm Gear Gearbox
 

The worms we used last year were 35:1 on the back of another transmission. I don't recall the ratio for the Bosch tranny we used however. We wanted an extremely high torque setup for our application though.

Pete

Re: Worm Gear Gearbox
 

Here is a design for positioning worm transmission from team 107 , the nice thing about our design is that there is 50 to 1 reduction on the worm which should make it not back drive. yet you can quickly change speeds and motor combination. It also can have either a pot or encoder mounted simply.



Thanks Jim schaddelee team 107

Re: Worm Gear Gearbox
 

We used two FP's last year to build a winch for climbing the bar. Be very careful about efficiency loss - we had ~ 30% loss. But it did lock up nicely and keep us hanging :)

Here's an mpeg of it running

Re: Worm Gear Gearbox
 

Doug

That looks great ,what was your reduction and did you lubricate the worm with anything?

Jim Schaddelee team 107

Re: Worm Gear Gearbox
 

To be honest I have seen a design that could work but it is really weird. It's the triple crown of complexity because it combines a worm gear, a cone drive, and a differential to increase the horsepower of a motor. The only disadvantage is speed is lost.

Re: Worm Gear Gearbox
 

Boston gear also produces stock worm drive gear boxes, they're really efficient for worm drives and are quite heavy duty. we used one in our drive train last year and it worked beautiful. Picture Here. I beleive these were a 20 to 1 reduction and these had no backdrive.

-Pat

Re: Worm Gear Gearbox
 

I did not think that you could buy gearboxes. I was under the impresion that you could only manufacturing them. Plus what is the fun in using premanufactured gearboxes, you dont even get the headaches or any of the flesh wounds that come with designing and building a custom gearbox. That is what makes it fun or at least when it is all over.

Re: Worm Gear Gearbox
 

Yes, you can buy gearboxes. Here is a well known example.

This is really up to the needs and opinions of each individual team.

If they feel that a purchased gearbox will meet their needs better than one that they designed and built themselves, then they should by all means go for it.

If they feel that they want the experience of designing and building their own, and have a unique design that they feel would meet their needs, then they should go ahead and do it.

The decision to buy or build is a matter of what each team feels is best for them.

For more thoughts on the matter... this thread.

-- Jaine

Re: Worm Gear Gearbox
 

For the most part, you can use whatever you can buy off the shelf, mechanically. So gearboxes are perfectly legal as long as they aren't custom made. Viz. AndyMark

Most people talk about building gearboxes for custom functions that an off the shelf one wouldn't fit for, or more commonly for a shifting transmisson that is difficult and expensive to obtain off the shelf. Or was, at any rate. See: Nothing But Dewalts

Re: Worm Gear Gearbox
 

In the case of off the shelf worm gear transmission, aka speed reducers, a COTS part is much heavier than a custom one. My experience with these is that they designed for heavy machinery and not the applications that we have.

One of the best off the shelf transmission choices 177 has made in the last few years was to get the trailer jack the chip was designed for and use that to power our shoulder in 2003. There are lots of good Commercial Off The Shelf parts if you know where to look.

Re: Worm Gear Gearbox
 

341 used a worm gear gearbox last year- we had a CIM geared down to match the drill motor on both sides, she wasn't as fast as we would have liked her to be (efficiency loss), but the entire year we never got pushed once- many times we met teams with much more powerful transmissions and they couldn't budge us, our frame got really beat up from that :P

but seeing as our main strategy was to hang quickly from the ground, winch up to the platform, and move back and forth on the platform, it was nice to know nobody could push us.

I personally am a fan of the multi-speed gearboxes over this worm gear gearbox, but if there was ever a game where you want to be a unmovable rock, like if you have to guard something, this gearbox is your man.

Re: Worm Gear Gearbox
 

Maybe this years game will give us a reason to produce a gearbox with wormgears. I would get no greater satisfaction out of life than watching another bot try to push us around. :D

Re: Worm Gear Gearbox
 

Does anybody have any links to information for calculating worm gear strength?