Spider gear continuous torque rating

jeepinmatt

jeepinmatt

#1 WEBWHEELER
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Mar 24, 2005
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Stanley, NC
I'd like to find a chart or some solid numbers of the continuous torque rating for spider gears. Mainly D30, D44, and D60, since I happen to have those sitting around.

I have this crazy idea, but it just might work.
I want to build a PTO reverser for my tractor. Not anything I can shift, just something that I can put inline between the PTO and the implement shaft.

If I had a housing with an open carrier, carrier held in place, I could plug one side into the PTO, and have a PTO like output on the other side that rotates in the opposite direction.
It could be simplified even further by eliminating the housing, and turning down the ring gear mounting face. It would have to mount to the tractor somehow to handle the torque, but that would be a simple bracket.

If I were confident that a set of spiders could handle 300ft-lbs continuously if kept in an oil bath, I might start thinking seriously about this. My tractor is 35hp, so thats about 340ft-lbs at 540rpms. While that wouldn't be the continuous load, certain activities would probably see 2-300 ft-lbs continuous (tilling).

My biggest concern is that the spiders wouldn't last with constant rotation. In a rearend, they spend most of their life just hanging out, not doing much. Rarely are they subject to continuous turning and loading. If you are spinning your tires, they aren't loaded, and if you get traction, they stop spinning.

Anybody got some numbers or thoughts for me?
 
Wouldn't the cast carrier be the weak link? Yes, although they are sitting still and rotating with the carrier, if you lose one tooth off the spider, then you lose more teeth.. They are under constant torque ( just not rotating), even when driving straight.
 
GONOVRIT said:
...You've got too much time on your hands.......
Click to expand...
Not really. With the work I'm doing right now, I'll have to wait 30 mins or more sometimes for programs to load or files to transfer, and my mind wanders and wonders.

It's not the max torque I'm worried about, I'm sure they can handle that, it's the continuous rotation while loaded.

This is a "one day" project, as in one day I may get around to it.
 
http://www.speedwaymotors.com/Winters-Quick-Change-Gears,1284.html
I've had a similar idea but I was thinking of making a small steel rectangular box and using quick change gears in it. You'd need to bore 2 through holes in the box that can accept sealed bearings. With the two gears turning against each other you'd get opposite rotation from each gear. On one side an input shaft the other side offset from that would be an output shaft. The biggest drawback would be that the input and output wouldnt be inline, making it harder to use in your case but its still something to think about.

What worries me about using spider gears is that they dont ride in bearings so long periods of high speed use will likely just cook them till they either seize up in the carrier or wear the face of the teeth to nothing.
 
MarsFab said:
...What worries me about using spider gears is that they dont ride in bearings so long periods of high speed use will likely just cook them till they either seize up in the carrier or wear the face of the teeth to nothing.
Click to expand...
This^

Although the idea makes since, it shouldn't be too hard to build something like MarsFab described, although, like he said it would offset just a bit.

On this note, my grandfather made a post hole digger for behind the tractor using a spooled Ford 9 inch:lol: works great.
 
MarsFab said:
http://www.speedwaymotors.com/Winters-Quick-Change-Gears,1284.html
I've had a similar idea but I was thinking of making a small steel rectangular box and using quick change gears in it. The biggest drawback would be that the input and output wouldnt be inline, making it harder to use in your case but its still something to think about.
What worries me about using spider gears is that they dont ride in bearings so long periods of high speed use will likely just cook them till they either seize up in the carrier or wear the face of the teeth to nothing.
Click to expand...
Any particular reason you picked those gears? Price seems pretty good.
The offset wouldn't really be a problem if the gears aren't too big. I can have the reverse output be above, and the shaft will have plenty of angle left.
My concern is also cooking the gears.

GCncsuHD said:
This^
On this note, my grandfather made a post hole digger for behind the tractor using a spooled Ford 9 inch:lol: works great.
Click to expand...
Is he from Gaston County? A friend of my dad's has a post hole digger made out of a Ford 9" also.
 
My dad bought a bunch of them at a racers auction a few years ago so I have a few to play with. I havent checked buy they have a course spline similar to the 6t of a cat. PTO.
 
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