pic: Don't do this. It's a bad idea.

[Michael Blake]

I can't figure out why you have four Bevel gears (forming a box, differential?) connected to the left wheel... couldn't you achieve the same by extending the shaft from the right wheel directly to drive the left wheel?

THANKS!

[lemiant]

Originally Posted by Michael Blake

I can't figure out why you have four Bevel gears (forming a box) connected to the left wheel... couldn't you achieve the same by extending the shaft from the right wheel directly to drive the left wheel?

THANKS!

Actually the box results in the two turning in opposite directions.

[MrForbes]

The differential is used in the drive axle of cars, read about it

http://en.wikipedia.org/wiki/Differe...ical_device%29

[Michael Blake]

Originally Posted by lemiant

Actually the box results in the two turning in opposite directions.

RIGHT, but you wouldn't want them to turn oppositely, correct?

This has me scratching-my-head... ;-)

[EricH]

Actually, Michael, lemiant didn't have a chance to read squirrel's link yet. I would suggest reading that link, then figuring out the drive system.

Short version: If both can go the same way at the same speed, both go the same way at the same speed. But if one of them can't keep that speed up, then it doesn't have to due to the way the differential is set up.

[Cuog]

http://www.youtube.com/watch?v=vBm-S...eature=related

Here's an animation of how a differential operates for those confused.

[MrForbes]

Here's a much better explanation.....but then, I do like old stuff

http://www.youtube.com/watch?v=F40ZBDAG8-o

[Michael Blake]

Originally Posted by squirrel

Here's a much better explanation.....but then, I do like old stuff

http://www.youtube.com/watch?v=F40ZBDAG8-o

NOW, _that_ was helpful... ;-) THANKS, Jim!!

[Michael Blake]

Originally Posted by EricH

Short version: If both can go the same way at the same speed, both go the same way at the same speed. But if one of them can't keep that speed up, then it doesn't have to due to the way the differential is set up.

So, where's the "slippage" provided in this setup?

THANKS!

[Hawiian Cadder]

Why not choose pneumatic tires over the suspension? I don think you would get much "play" before the bevel gear bottoms out.

[Cuog]

Originally Posted by Michael Blake

So, where's the "slippage" provided in this setup?

THANKS!

There is no "slip"* in a differential. The nature of how the gears mesh is what allows the shafts to turn at differing rates. The differential itself has no control over the situation, its just along for the ride.

*(unless we start talking limited slip differentials and lockers etc)

[EricH]

Originally Posted by Michael Blake

So, where's the "slippage" provided in this setup?

THANKS!

In the differential gearing. Two of the 4 gears in the inner box are connected to the wheels; the other two are idlers. The relative speed of the wheels doesn't really matter to the idlers; they'll move as fast as they need to.

Hint: Think of this setup as 2 gearboxes. The inner box is the 4 in the middle of the "axle"; the outer is the bevel at the top and the large gear it meshes with.

[Michael Blake]

Originally Posted by EricH

In the differential gearing. Two of the 4 gears in the inner box are connected to the wheels; the other two are idlers. The relative speed of the wheels doesn't really matter to the idlers; they'll move as fast as they need to.

Hint: Think of this setup as 2 gearboxes. The inner box is the 4 in the middle of the "axle"; the outer is the bevel at the top and the large gear it meshes with.

Also, helpful... THANKS, Eric!

[lemiant]

Originally Posted by EricH

Actually, Michael, lemiant didn't have a chance to read squirrel's link yet. I would suggest reading that link, then figuring out the drive system.

Short version: If both can go the same way at the same speed, both go the same way at the same speed. But if one of them can't keep that speed up, then it doesn't have to due to the way the differential is set up.

I hadn't. I thought the big bevel was attached to the shaft not the box. After reading that article I understand, and am amazed!!!!

[Tristan Lall]

Wouldn't this work better with constant velocity joints (rather than universal joints)?

And are you using the universal joint as two of the members in a four-bar linkage that holds up the wheel? If so, isn't it just going to deflect to the maximum? (Or am I missing a spring somewhere?)

This would be a fun stock design to keep around...just to tempt people when FIRST decides to give us some real obstacles.