45° Stepper Mechanism.

[Anto]

I'm back with something new!

For my new gearbox, I needed a 45° shifter. At first, I reproduced the one of the Yamaha MT-10 SP, but I was not satisfied with it. Indeed, I didn't like the feeling (you have to assist the lever until the gear is shifted, it doesn't feel like a keyboard touch) and the return to center doesn't work properly. This is why I decided to work on a new shifter having the following features:

• "Keyboard" touch
• Uses only one 8 tooth stepper gear
• More compact 45° lock-mechanism
• Working return to center

 

The architecture is based on the one of the shifter from the Bugatti Chiron, using 135° connectors. Here, I used a tile round with bar holder to obtain the right distance between the connectors and the gear.

 

The result is a compact shifter with a nice feeling, a working return to center and that only uses one 8 tooth shifter gear.

 

Link to Rebrickable: https://rebrickable.com/mocs/MOC-175515/Anto/45-stepper-mechanism

[2GodBDGlory]

Looks very nice! I'm working on a model with a 45 degree stepper right now, so I guess I'll have to see if it's too late to incorporate this design or not!

Either way, I look forward to trying out this design!

[2GodBDGlory]

Built it now, and it is quite satisfying to use! It doesn't fit in my WIP model, though, unfortunately. Thanks for sharing!

Edited February 29, 2024 by 2GodBDGlory

[R0Sch]

You could also now use a pair of knob gears (black + lbg) on the same axle to achieve the same 45° stepper mechanism if you lack the new yellow stepper gear. It would just be 1M wider.

Edited March 1, 2024 by R0Sch

[2GodBDGlory]

12 minutes ago, R0Sch said:

You could also now use a pair of knob gears (black + lbg) on the same axle to achieve the same 45° stepper mechanism if you lack the new yellow stepper gear. It would just be 1M wider.

I'm sure that a stepper could be made that way, but I guess it would require some pretty significant changes from this design

[Timewhatistime]

15 minutes ago, R0Sch said:

You could also now use a pair of knob gears (black + lbg) on the same axle to achieve the same 45° stepper mechanism if you lack the new yellow stepper gear. It would just be 1M wider.

Both ideas are great (even if the knob gear stepper is not built yet)!

We all should think more about alternatives. In most cases, there are quite a few ways to reach the goal and to decrease the dependancy on rare/new/special parts.

Edited March 1, 2024 by Timewhatistime

[R0Sch]

57 minutes ago, 2GodBDGlory said:

I'm sure that a stepper could be made that way, but I guess it would require some pretty significant changes from this design

Not really. Just double the width of the #3 connector so alternates between black and grey knob gear. The rest should work the same way. Maybe I'll do a quick mock-up in Studio later on.

[2GodBDGlory]

1 hour ago, R0Sch said:

Not really. Just double the width of the #3 connector so alternates between black and grey knob gear. The rest should work the same way. Maybe I'll do a quick mock-up in Studio later on.

Hmm, maybe, but it seems like the tooth profile would be different enough that some other things would need to change. For one, I think the part that springs to lock things into position wouldn't work with the split part, since it would only be engaging with one knob wheel. Also, you might need to adjust the lengths of the arms (where those #3 connectors are) to engage with different size teeth.

It could be worth looking into, though!

[R0Sch]

At first I did what I said and simply replaced the stepper gear with knob gears...


...but then I found the modified 1x2 liftarm with bar piece and I think the whole stepper mechanism can be shrunk down 1M in length. Of course the width would still be 1M wider than what Anto proposed. Maybe someone can test it out. Not sure if it works well. I used the 3L pin with towball.

Edited March 1, 2024 by R0Sch

[2GodBDGlory]

Interesting design, especially with the rubber pieces to step the "steps"! I worry a little bit about that 5L axle through the rubber parts rotating inside them if too much force is put on the rubber band, but it's hard to say.

Also, the 3L pin with towball you have won't work in real life, because the towball can't fit through a pinhole. However, that could be easily replaced with a 2L pin plus a towball with bar, or just a 3L pin with axlehole.

I'd give it a test build, but I don't have any of the offset knob wheels yet...

[Davidz90]

I wonder if it's possible to build something like this but with 8t gear. Did some experiments, I could do a single direction stepper no problem, but two-directional one eludes me. Also, rubber connectors are great for replacing rubberbands when flexible components are needed.

[Anto]

@R0Sch: I also had the idea to use 2 knobs, but I don't have gray knobs to test in real life... Be careful when you try to design a stepper in Studio, because in real life, even when you think that it could work, you often have bad surprises. So with a virtual design, it's even worse! Anyway, these prototypes are interesting and must be tested in real life!

 

3 hours ago, Davidz90 said:

I wonder if it's possible to build something like this but with 8t gear. Did some experiments, I could do a single direction stepper no problem, but two-directional one eludes me.

I have quickly tried, and it seemed compromised. The tooth are so small that it's hard to push on them correctly. It's also difficult to make a good 45° lock-mechanism using 8t gears.

[Davidz90]

2 hours ago, Anto said:

I have quickly tried, and it seemed compromised

Here's my quick and dirty prototype. Works just fine in one direction, adding second pallet below is problematic.

 

[Anto]

Your prototype is interesting, but in order to be used, the axle connected to the 8t gear has to have positions multiple of 45°. Here, the positions are n times 45° + 22.75° - you can't make the cross axle perpendicular to the liftarm. If you want to correct this, you must change the lock-mechanism a little, but it will be way harder to create a clamp that is able to push the teeth of the gear. It's hard to explain, but if you try, you'll understand what I mean! (I hope )

[Davidz90]

Yes, I understand, valid point. I'll try a few things tomorrow.

[Davidz90]

Ok, here's a decently working stepper mechanism with 8t gear, now properly aligned with beams:

I'm not 100% satisfied with the reliability, but the idea seems viable.