Free 173 Best Homemade Tools eBook:

# Thread: Exposed planetary gears in heavy equipment - GIF

2. ## The Following 2 Users Say Thank You to Jon For This Useful Post:

baja (07-13-2019), Scotsman Hosie (07-14-2019)

3. Let’s hope no crud falls in there before this gearbox can get buttoned back up. Could be disastrous.

4. Is that CGI?

5. That is the primary planetary set, if you look close through the space between the carrier and the outer ring gear, you can see part of the secondary gear set behind it. Awesome torque multiplication capability.

6. ## The Following User Says Thank You to hemmjo For This Useful Post:

jimfols (07-14-2019)

7. Fascinating could watch those gears move all day.

Amazing the torque that little center shaft must take.

Ralph

8. Originally Posted by Ralphxyz
Amazing the torque that little center shaft must take.

Not as much as you might think, I count 10 teeth on the spur gear, the idlers have no effect on ratio, the outside ring gear has at least 90. So the primary gear set is 9:1. If you look close there is a secondary planetary set behind the one you see. The secondary set cannot be as high a ratio, lets guess that it is about 5:1.

5 x9 = 45:1 So, if that "little" center spur gear (looks to be about 1 1/2") outputs 1000 lb/ft of torque the drive wheel outputs 45,000 pound ft of torque.

9. ## The Following User Says Thank You to hemmjo For This Useful Post:

jimfols (07-14-2019)

10. That center shaft looks more like 3/4" which is why I remarked at the torque.

Ralph

11. I do not think it can be 3/4". Attached is a scaled screen shot. If the spur is 3/4" the track is only about 10" high. If the spur is 2" then the track i closer to 26-27".

A 10" tall track is a really small machine.

Now that I have looked really close doing the scaling, am wondering if 12Bolt has the right idea. It could be fake. No mechanic work his pay would be running that with no lubrication. I see no indication of oil on the parts. There is no lube spilled on the tracks or outside the hub. In addition the whole gear set does not appear to be fully inserted into the ring gear and the spur is not fully engaging the idlers.

It is all speculation.... but the discussion is interesting.

12. My initial thought that it could be CGI was not so much that it was fake, but so as to show the internal workings for the uneducated.
Originally Posted by hemmjo
...am wondering if 12Bolt has the right idea. It could be fake....
My thinking was based that I would have thought the outer idler gears and the plate they are mounted on would be retained in place by the outer "missing" cover. If that idler set was to slip out under power I imagine the result wouldnt be pretty

There are currently 1 users browsing this thread. (0 members and 1 guests)

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•