pic: NanoShifter
 

Re: pic: NanoShifter
 

This render is amazing

Re: pic: NanoShifter
 

AMAZING! :D That is just (insert word to majorly increase awesomeness)ing awesome!

How much does it weigh?
How stable is it?
When and where will I be able to get one?!

Re: pic: NanoShifter
 

If you could make the final ratio faster I imagine it'd be a cool / compact way to do a 4" wheel transmission. Gotta get rid of that mecanum wheel first though.

Re: pic: NanoShifter
 

If you went with 4" wheels, the standard AM shifter gears would work. I'm not sure it would make sense to do it though, if you did a 6 wheel drive you'd need 6 of these. May only make sense with Mecanums.

Re: pic: NanoShifter
 

The way I see it, depending on the weight of these things, and the do look light, one could use 6 of them, one per wheel, or at least 4 of them, 2 on each side, making a very powerful drivetrain.

Excellent gearboxes for mecanums, however I see a lot more use in these than mecanum wheels.

Re: pic: NanoShifter
 

If you used six, you would have to have six motors in your drivetrain. Also, if you used 2 on each side for a non-omidirectional drivetrain, you would save weight by simply using one transmission. The power would be the same since the motors supplying the power are the same as they would be with two gearboxes.

I agree that there are more uses for them than mecanum, they could be useful in swerve and omni-drives. But they could also be useful in non-drivetrain applications like shooters.

Re: pic: NanoShifter
 

If 2 of those weigh less than one of the standard transmissions, it'll be less weight no matter what. Plus, you gotta admit: Just by seeing it you wanna use it on a robot. :)

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A standard Nano weighs 4.8 lbs without motors. I can't imagine shifting ones weigh too much more.

A SuperShifter weighs 4 lbs. without motors and pneumatics.
AM Shifter weighs 3.4 lbs. without motors and Pneumatics.

I would just stick to the standard SuperShifters or AM Shifter.

Re: pic: NanoShifter
 

Fine, don't use the really cool greatly rendered awesome-sauce gearboxes. :|

Re: pic: NanoShifter
 

A ToughBox Nano weighs ~1.7 lbs...?

Were you thinking of a NanoTube?

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If designed right the additional weight going from a single to two motor gearbox is a little more plate, and an additional pinion gear; far less than a second set of gears.

Re: pic: NanoShifter
 

Haha. Good catch. I was indeed thinking of the Nano Tube

Re: pic: NanoShifter
 

First, amazing render. I don't think anyone here will ever get tired of these types of ideas, so don't feel the need to 'quit'. They're creative and are a spring board for a final product.

Any way the encoder can be re-incorporated into the gearbox?

It also appears that the inner races of the bearings on the last stage touch the inner races of the bearings in the housing. Would this cause a problem due to the difference in speed of each shifting gear?

Re: pic: NanoShifter
 

You have a good eye for detail. If this was real, I'd put a thin washer between the inner races like the bearings on the other side of the same shaft have.

The easiest place to put the encoder would be on the cluster shaft. This could cause a few problems - getting it to clear the CIM might be an issue, the speed might be too high for the encoder and you need to know for sure which way you were shifted.

That brings up another challenge - if 3 of the positions shifted and the 4th didn't you'd have a mismatch. If the shift position was detectable you could compensate the CIM speeds and get a "limp home" mode.

If the encoder didn't work on the clutster shaft, I'd probably try to change the shift cylinder setup so I had access to the end of the shaft (not sure what that would look like.)

Re: pic: NanoShifter
 

As for an encoder:
-It could go on the other end of the wheel shaft
-You could use a code wheel on the wheel itself
-You could use a gear tooth sensor on one of the gears - This does not know post-shift speed


As for not all shifting:
-How would this issue be any different than that of using (2) Dewalt transmissions per side, except that pneumatic shifters are faster than servos?
-I think, using the highly reliable Andy Baker shifting transmission design, and properly protecting the pneumatic system from damage, you should be OK if you don't explicitly detect and handle the issue of one transmission not shifting.


Another issue I may have missed: How do you get everything into the box? It looks like it is impossible to assemble, specifically the shift shaft.

Re: pic: NanoShifter
 

That's the question I've been waiting for. It's bit like building a ship in a bottle. I think I can be done but I haven't thought through every step. This would be a good excersize for someone - explain the exact sequence of putting the shift shaft together.

Re: pic: NanoShifter
 

please to give us the CAD file?

Re: pic: NanoShifter
 

Yes! Please to give to everyone! :D

Re: pic: NanoShifter
 

Step 1: Press 3/8" bearing

Step 2: Insert small shifter gear into tube, align and insert shift shaft with dog assembled.

and

Brick wall..

even if you flipped the last bearing there is no way to get the other gear on the shaft. It may have some way out there solution but I don't see it. The hex boss on the shifter shaft creates a mechanical limit.

May I suggest putting a hole large enough for the gear (and entire shifter assembly) through and use 1/8" plate to patch the hole. To determine alignment use pins and threaded inserts for fastening in such a compact space. You may have to do this to insert all shafts and gears. Using the tube to determine spacing and fit, Swiss cheesing the outer wall and making a single face plate to close off the assembly.

Re: pic: NanoShifter
 

Step 1 was good - try something else for step 2.

Re: pic: NanoShifter
 

I'll send it to Matt at FRC Designs.

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If the press fit between the shift gears and their bearings was light enough, and the diameter of said bearing on the low gear side was less than or equal to the diameter of the dog AND less than or equal to the diameter of the hole for the flanged output bearing, this would work:

(A quick check of AM shows that the dog gear has an OD of 1" and the low gear uses an R8 bearing (1.125") - this would work possibly)

1. Insert the rear bearing (piston side) and press it in
2. Insert the two shifted gears into the tube
3. Assemble the shift shaft with the bearings, dog, and other bearings
4. Insert through front (output side) of transmission, pressing bearings into gears as you went
5. Press on output bearing from the outer side - If I am correct, this will be fine as the wheel will hold the bearing on
6. Assemble the cluster shaft like the current way AM does it
--One bearing is flanged and inserted first
--All of the gears are inserted and the shaft is inserted from the outside, through all of the gears into the inner bearing
--The outer bearing is inserted, and the two screws hold it
7. The CIM motor is the easiest part.
8. Assemble the shift linkage - This is standard AM shifter stuff

Re: pic: NanoShifter
 

Both the large gear idle bearing and the shaft bearing have the same 1.125" OD but both also have the 1.125" OD flange (I think). So up to this point you could fit the shifter shaft and the dog though the bore in the large gear but inserting the idle bearing is another road block.

EDIT: never mind the small gear is the one with flanged bearing but now the concern is with the lip that the bearing bottoms out on on the larger gear. Is this ID large enough to allow the dog to pass through.

Re: pic: NanoShifter
 

You're close:

The dog and the bearing for the small gear need to be in before the shaft.

You have to be careful how you press the bearing for the large gear in - press on the outer race only.

How do you get the spring pin through all three pieces (dog, output shaft and shift shaft.)

Re: pic: NanoShifter
 

The idler bearing does not have a flange but the bearing in the housing does. Notice that there is a sleeve around the bearing so the flange will fit through the hole. You can't see it in this render, but there are two screws like the one on the cluster shaft holding the output flanged bearing in place.

Re: pic: NanoShifter
 

Quote from @FRCDesigns

Re: pic: NanoShifter
 

The easiest assembly method would probably be to cut the tube in half, assemble the innards, and put the housing back together. The reassembly of the housing could be done with plates and rivets tapped holes and screws/bolts, or welding. The second would be best for maintainability.

Re: pic: NanoShifter
 

You are correct - but part of the fun for me was to explore if it was possible to assemble with the rectangular tube intact. (BTW, if the tube is a single piece disassembly is difficult also, to get the pressed bearing out of the large gear you have to press from the other end of the shaft - this may damage the bearing.)

Re: pic: NanoShifter
 

I think this would be the best method, with standoffs located at the 4 pre-made holes on the corners of the extrusion. Of course, the thickness of the standoffs may interfere with my next topic...

The ratios do not appear to be that much different from each other with this gearbox. I presume this is due to sizing restrictions? 2 methods to deal with this are:

1.) Increase the diameter of the driven low-speed gear, which would then require slots in the housing and thin standoffs or no standoffs from the assembly method above.
2.) Decrease the diameter of the driven high-speed gear, which may require yet another custom gear for the dog gear to mate to.

Which brings up the question -- what is the smallest size 20DP gear that can be pocketed out for mating with the dog gear?

Re: pic: NanoShifter
 

All the gears shown are custom. It looks like the standard shifter (AM-0001) was set up for 4" wheels. The 6" wheels cause some trouble with ratios.

The ratios shown are at about 8 and 12 fps. The high speed (12 fps) ratio could be made faster with no problem. The large output gear already interferes and would need a clearance cut in the housing as it is. 8 fps isn't too bad for mecanums anyway - wheel slip is around 9 fps so you don't get much benefit for going slower.