[HELP] Generic Building Help Topic

[npicard]

Hi everyone,

My motorized gearbox is coming along well, but I have a new issue. I have a motor that needs to flip several driving rings at once. I could gear down and up the torque a lot, but I don't want to break any axles.

Currently I'm putting the driving rings on the white 18948 Driving Ring Connector. I'm aware that I could put them on the gray/black 26287 Axle Connector 3L, but this offers no assurance that the driving ring will stay engaged with the clutch gears.

So I'm looking for a way to keep the driving ring engaged with the clutch gears that requires very little force to overcome. One possibility I considered was sandwiching a square-profiled part between two parts connected by an elastic band, a solution I've seen in various stepper mechanisms. Unfortunately, this requires a quarter turn to be effective. The changeover catch only completes about a sixth of a turn (?) when flipping between the two extremes of the driving ring. I could use this solution if I geared up the changeover catch axle at a 3:2 ratio, except this would introduce lots of backlash.

My dream solution is a Driving Ring Connector with smaller "bumps" to overcome, but I don't modify parts. Any ideas? Thanks!

Edited September 26, 2021 by npicard

[Keegan Pilling]

So basically, you need enough resistance to keep the driving rings engaged, but not so much that a motor can’t switch them?

In saying this, is it also safe to assume that you don’t want any extra friction on the driving ring? Meaning that applying constant pressure with a 6641 changeover catch is not an option.

I’m assuming you don’t have any of the orange Chiron shifter rings?

Your best bet might be in eliminating the driving rings.. although that might not work, depending on the application.

How much load will this have to handle?

Maybe some pictures would help. 
 

Edit: just looked back in the thread, is this the same gearbox you were working on in August?

Edited September 26, 2021 by Keegan Pilling

[npicard]

On 9/26/2021 at 2:30 PM, Keegan Pilling said:

So basically, you need enough resistance to keep the driving rings engaged, but not so much that a motor can’t switch them?

Yes, exactly.

Quote

In saying this, is it also safe to assume that you don’t want any extra friction on the driving ring? Meaning that applying constant pressure with a 6641 changeover catch is not an option.

Exactly. Here's a picture. Select gear by driving bottom axle. Depending on direction, the worm gear travels to the correct z8 gear which drives the white "paddles," which in turn flip the changeover catch. No constant pressure, since the white paddle just keeps spinning until the input axle changes direction.

[edit: image removed]

Edit: as you can see, I used your suggestion for Sariel's pneumatic autovalve. It worked perfectly and is very reliable. It didn't fit all of my constraints, but it was such a good solution that I solved them in another way.

Quote

I’m assuming you don’t have any of the orange Chiron shifter rings?

I do. I guess I could come up with a new system to have the worm gear select between states. That requires a half-turn though, so I really don't know how I'd approach that. Those little paddles sure won't do it!

Quote

How much load will this have to handle?

This subsystem will actually experience very little load. The problem is that a lot of torque is taken up elsewhere, so there's not a lot to share. (As in, sometimes a motor will be switching many of these at one time.) So torquing up will mean a lot of stress "upstream." That's why I'm looking for a solution that puts almost zero load on the motor.

Thanks for the thoughts so far.

Edited November 4, 2021 by npicard

[Keegan Pilling]

I’ll see what I can come up with.

[2GodBDGlory]

One option would be to use the old 2L driving ring, which offers two different axle extenders with friction in between the two 3L ones. I had a similar situation recently, and my solution, though kind of weird, was like this, just with the driving ring and gears on the adjacent spots on the axle. The 4L bar can be replaced with a 3L to save space. The main disadvantage is that the one end of the axle can't transmit torque. Sometimes this doesn't matter; sometimes it's crucial.

The 2l axle extender allows for a medium amount of friction.

 

[Keegan Pilling]

14 hours ago, 2GodBDGlory said:

One option would be to use the old 2L driving ring, which offers two different axle extenders with friction in between the two 3L ones. I had a similar situation recently, and my solution, though kind of weird, was like this, just with the driving ring and gears on the adjacent spots on the axle. The 4L bar can be replaced with a 3L to save space. The main disadvantage is that the one end of the axle can't transmit torque. Sometimes this doesn't matter; sometimes it's crucial.

The 2l axle extender allows for a medium amount of friction.

 

Why did you use the 4L bar? Couldn’t you just use an axle with a 6590 bushing, with the + shaped side up against the grey shaft connector? In my experience that still allows full movement of the driving ring while also allowing for different shaft lengths :)

Edited September 27, 2021 by Milan
Do not quote images from the same page, please.

[npicard]

Thanks for both of your responses.

I've tested out 2GodBDGlory's suggestion and the friction is pretty much what I'm looking for. I don't need torque transmission through the powertrain axle, so that's fortunately not a problem for me. The only real issue is the funny 4L bar sticking out the end. It's not very aesthetic, but it absolutely gets the job done. :) (Edit: Another minor issue is the friction on the black 18651 Axle 2L with Pin. A third minor issue is the friction is a little high, see below.) (Edit 2: I just learned about the white 65249 Axle 2L with Pin without Friction. I don't own this part as it's new this year. It seems exceedingly useful!)

Keegan Pilling, your suggestion of using a 6590 bushing is good. In fact, it actually improves this solution by reducing the friction. The reason is, 2God's setup as-is allows the springs in the driving ring to "dip" closer to the black axle portion. When you move it back to the left, it has to "overcome" this dip. High-friction for a moment. The bushing prevents it from ever falling into the dip.

HOWEVER, the bushing has that pesky O-shaped end. This prevents the driving ring from fully engaging with the clutch gear on the right. This isn't a problem for clutch strength or torque transmission or anything, and most people probably wouldn't care. (It's less than a quarter module error.) However, in my build, the white paddles need clearance to continue their circular path. The tiny error introduced by the O-end of the bushing actually prevents them from clearing the changeover catch.

So, KP's modification of 2God's solution would solve my problem perfectly if it weren't for the asymmetry of the 1L bushing.

Edited September 27, 2021 by npicard

[2GodBDGlory]

1 hour ago, Keegan Pilling said:

Why did you use the 4L bar? Couldn’t you just use an axle with a 6590 bushing, with the + shaped side up against the grey shaft connector? In my experience that still allows full movement of the driving ring while also allowing for different shaft lengths :)

I tried using the bush first, but the O-shaped end prevented full engagement for me. Mine was for a gearbox in a car, which tends to stretch gearboxes to the limit, so I wanted full engagement despite the costs.

The 4L bar is annoying, but as I said, a 3L can be used instead, as can a cut 2L section of 4mm hose.

@npicard Good idea to use the white pin; I forgot about it.

I hope you're able to find a satisfactory solution!

[npicard]

I realized I can solve the problem of the incomplete engagement due to the O-end of the bush in another way: by shortening the relevant white paddle.

This would require a part that has an axle hole and a protrusion that is only around 1.75L.

My first thought was the 49283 Axle and Wire Connector, but unfortunately it's more like 1.95L and suffers from the same problem as the 2L liftarm.

My second thought was the 24122 Lightsaber Hilt. Unfortunately, its protrusions are exactly 0.5L each, making it effectively a 1.5L liftarm for the purposes of this problem. It's too short and doesn't engage the changeover catch! Even 1mm more length would make it perfect for the job.

Still no perfect solution. Best one yet is 2God's version with the new white pin and a 3L bar.

[2GodBDGlory]

Here's a slightly stronger and more compact version of my solution. Unfortunately it doesn't solve your main problem, but I think it's better in other respects.

 

 

[2GodBDGlory]

CADA half-bushes have the right outer profile, I believe, so two of them could nicely replace the proposed full bush. Too bad they ain't Lego!

[npicard]

Nice solution. I'll have to dig through my unsorted System to find a 3L bar, but unless anyone can come up with something better, I'll probably go with this. Thanks!

@Keegan Pilling I haven't forgotten about you! I won't be surprised if you pull something out of your hat.

[npicard]

14 hours ago, 2GodBDGlory said:

Here's a slightly stronger and more compact version of my solution. Unfortunately it doesn't solve your main problem, but I think it's better in other respects.

Update: this solution doesn't work as-is for a surprising reason. The 3L bar is exactly 3L. The 3673 Frictionless Pin has a stop in the very centre, so the 3L bar can't actually go 1L into it. It can go something like 0.95L into it. This means the whole assembly (pin, 3L bar, and axle connector) are very slightly over 5L – around 5.05L. This matters because the axle connector presses up against the red clutch gear, creating friction with it. In my application, the red clutch gear next to the axle connector sometimes turns in the opposite direction as the powertrain axle on which it spins. The resulting friction is doubled and we lose all our gains from the entire solution.

However, a very simple modification saves it: replace the 3673 Frictionless Pin with the 32003 Pin 3/4. It allows a 3.18 bar to pass as deep into it as you like. This solution requires mounting the entire axle with a thin liftarm on that end. I actually ended up mounting it with a 44 Axle and Pin Connector Toggle Joint Smooth.

It's now working perfectly and I'll happily mark this help request resolved.

Edited September 28, 2021 by npicard

[2GodBDGlory]

I'm glad you got something figured out!

[Thirdwigg]

I'm never sure where to place Stud.io help questions.

Anyone know why my instructions from Bricklink Studio are looking fuzzy? What setting have I inadvertently checked?

How do I make it looks like this again?

[lcvisser]

@Thirdwigg I think I tried every setting, but I can't reproduce it.  I believe (but not sure) that render settings are global setting; do you get the rendering quality in the above image in every model you try to render, or is it only in a specific file? Also, do you get the same behavior via the "Render Image" menu, or is that better?

[Thirdwigg]

19 hours ago, ludovisser said:

@Thirdwigg I think I tried every setting, but I can't reproduce it.  I believe (but not sure) that render settings are global setting; do you get the rendering quality in the above image in every model you try to render, or is it only in a specific file? Also, do you get the same behavior via the "Render Image" menu, or is that better?

Yeah, the issue seemed to resolve itself. I'm not sure what happened, but it was occurring for all my files. I walked away for a couple of days, and it seems to be back to normal. When it happened, I would get the issue in all render qualities, and for all MOCs, and for PNG or PDF renders.

I don't know what it was, but I'm happy its gone for the time being.

[m00se]

Is the amount of power that the control+ hub sends to the motors dependent of the number of motors attached even if  others are running? It seems so in my case but it doesn't make a lot of sense to me (using the Buwizz app).

 

Update: my bad, turns out I was just putting too much stress on that one motor; had nothing to do with the amount of other motors connected.

Edited November 20, 2021 by m00se
update

[Zerobricks]

On 11/13/2021 at 6:22 PM, m00se said:

Is the amount of power that the control+ hub sends to the motors dependent of the number of motors attached even if  others are running? It seems so in my case but it doesn't make a lot of sense to me (using the Buwizz app).

The more motors you are using, the more the battery voltage drops.

[m00se]

23 hours ago, Zerobricks said:

The more motors you are using, the more the battery voltage drops.

Of course if the others are running, but could there be an effect of just other motors being connected and not running?

[Jurss]

11 hours ago, m00se said:

but could there be an effect of just other motors being connected and not running?

Just additional weight, which will add additional load on driving motors.

[JozefJ]

Hi all,

I recently bought the Cat D11 bulldozer set. When testing the electronics, the axles do not rotate in the same way the Control+ app shows on the screen. I redid the entire build of the wheels (bag 1) but no change..

Does anyone recognise this issue? Or is this normal and is the 'test-mode' in Control+ purely to test if the functions are working at all?

Thanks for thinking with me!

[StudWorks]

Hello, today I made a rear spoiler for my sports coupe, but I am trying to figure out how to make the retracting mechanism, and connect it to the medium EV3 motor.

Any advice?

[2GodBDGlory]

My first thought is to just mount the spoiler on some vertical axles that would allow it to slide up and down, and then control it off of a 3-4L beam connected to the output of the motor, which would push/pull a link to move the spoiler up/down. You'd have to add a slip clutch if you were using a normal motor, but since you've got the EV3 one you should just be able to program it to move the required number of degrees.

[Jurss]

Depends on what You want - to lift it or change just angle (open it), or both together.