pic: NanoShifter

[JesseK]

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?

[Tom Ore]

Originally Posted by JesseK

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?

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.)

[apalrd]

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.

[Tom Ore]

Originally Posted by apalrd

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.

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.

[Ninja_Bait]

Originally Posted by Tom Ore

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.

please to give us the CAD file?

Originally Posted by Ninja_Bait

please to give us the CAD file?

Yes! Please to give to everyone!

[Tom Ore]

Originally Posted by SuperNerd256

Yes! Please to give to everyone!

I'll send it to Matt at FRC Designs.

[apalrd]

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

[A_Reed]

Originally Posted by apalrd

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

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.

[Tom Ore]

Originally Posted by A_Reed

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.

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.

[Starke]

Quote from @FRCDesigns

The Nanotube gearbox concept model from FRC525 has been added to FRC Designs! Check it out! http://frc-designs.com/html/gearboxes.html

[PAR_WIG1350]

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.

[Tom Ore]

Originally Posted by apalrd

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

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.)

[A_Reed]

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.

[Tom Ore]

Originally Posted by A_Reed

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.

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