Didumos69

[POC][WIP] Compact 90° stepper w/ instructions

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After shortening the travel required to shift gears in my improved paddle shifter unit for the Porsche (42056), I put some effort in trying to use the same concept - a lever knob gear driving a central knob gear - as a base for a 90 degree stepper. I was able to make a compact setup with the shift lever directly operating the shift axle that could in turn drive the clutches of a gearbox (the gearbox is not part of this unit). By using the knob gear inside the shift lever, the rotation speed of the central knob gear is twice the rotation speed of the shift lever itself. As a result each shift requires only a relatively short travel.

The stoppers that catch the upper knob gear when shifting are the crucial part of this mechanism. They had to be reliable when it comes to catching the knob gear and needed to allow for a smooth return at the sane time. The whole setup relies on its interaction with the simple 90° limiter., which has been integrated in this unit. I'm very happy with the result.

EDIT: I've been working on this a little more. I'wasn't completely satisfied about the return of the shift lever. It requires a lot of silicon power and I couldn't get it working with a new set of red silicon bands. Apparently the old ones (+/- 8 years old) are stronger. So I decided to skip the auto-return completely. The return is not needed for a full shift and a completely manual operation of the shift lever gives a nice feel. Returning the lever can actually be postponed until the next shift. This also allowed me to make an even more simple version of the stepper. In that simple version a different 90° limiter now operates directly on the lower knob gear. The limiter allows for some free movement of the orange paddles, but my guess is that this won't give any trouble when they operate the clutches of the gearbox. So all together I now have two versions: The compact stepper with separate 90° limiter and the simple stepper with limiter directly applied to the lower knob gear.

Compact 90° stepper with separate limiter (LXF-file)

Simple 90° stepper (LXF-file)

Comments and (suggestions for) improvements are welcome!

Edited by Didumos69

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1 hour ago, efferman said:

this is brilliant

Thanks!. It was just a matter of combining ideas. The concept of using knob gears this way actually comes from the paddle shifter unit of the Porsche. The idea was good, but LEGO's implementation was bad.

Edited by Didumos69

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1 hour ago, Didumos69 said:

It was just a matter of combining ideas.

And you combined them very well. Nice work. :wink:

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Awesome work! It looks so simple, but of course getting it to work so well is not simple at all.  It's also great to see several people's great ideas combined.

I would like to see a version that can be switched by a motor (M or servo).  It doesn't seem so easy to adapt this particular design, because the shift lever is not fixed to an axle - am I right?

Edited by aeh5040

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@Attika, @aeh5040, @Paul Boratko, thank you guys!

3 hours ago, aeh5040 said:

I would like to see a version that can be switched by a motor (M or servo).  It doesn't seem so easy to adapt this particular design, because the shift lever is not fixed to an axle - am I right?

Indeed the shift lever is not fixed to an axle. I don't think this mechanism is particularly useful in a motorized gear changing setup.

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On 10/20/2016 at 0:47 AM, Attika said:

And you combined them very well. Nice work. :wink:

 
I thought I should at least make a short note on how I got to this. I got inspired by @Attika's compact sequential stepper. His stepper triggered me to try and see whether I could apply the same concept to the paddle shifter unit of the Porsche. Although I got that working quite nicely, the issue with it was that the paddles needed to travel extensively to make a single shift:
 
 
And when I integrated it into my Porsche it was still not enough to actually shift gears. This also had to do with the fact that in my case it had to set quite a few things in motion, not only the driving rings in the gearbox, but also the HoG shifter and the dashboard gear indicator. So I reverted to the original Porsche paddle shifting mechanism and re-established the side knob gears. But this time with a renewed casing and more importantly, a more simple and reliable way to catch and return the side knob gears, without using any moving change-over catches or rubber connectors:
 
 
This simplified catch-and-return setup allowed the side knob gears to be aligned perfectly to the left and right sides of the center knob gear when the paddles are in idle position. This did not only result in a significantly shorter travel of the paddles to shift gears, but it also made this catch-return concept suitable for operating in two directions. And that's exactly what this stepper does, albeit with slightly different catch-return stoppers.
Edited by Didumos69

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I made some adjustments to make it possible to have two independent axles running right through the middle of the unit. I needed that myself to route drive and steering from the rear side to the front side.

LXF-file here (the silicon bands need to be routed over the yellow bushes and yellow half bushes inside the unit, I will post a video soon).

Edited by Didumos69

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I've been working on this a little more. I'wasn't completely satisfied about the return of the shift lever. It requires a lot of silicon power and I couldn't get it working with a new set of red silicon bands. Apparently the old ones (+/- 8 years old) are stronger. So I decided to skip the auto-return completely. The return is not needed for a full shift and a completely manual operation of the shift lever gives a nice feel. Returning the lever can actually be postponed until the next shift. This also allowed me to make the whole thing even more compact, a different 90 degree limiter now operates directly on the lower knob gear. The limiter allows for some free movement of the orange paddles, but my guess is that this won't give any trouble when they operate the clutches of the gearbox.

960x450.jpg960x450.jpg

Comments and (suggestions for) improvements are welcome!

LXF-file here.

 

Edited by Didumos69

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Great ideas, you became Eurobricks's sequential stepper developer. :classic: 42056 shifter mod will be more and more perfect.

Edited by Tamas Juhasz

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4 hours ago, Tamas Juhasz said:

Great ideas, you became Eurobricks's sequential stepper developer. :classic: 42056 shifter mod will be more and more perfect.

Thanks!

To show how reliable this small stepper is, I wanted to attach it to a real gearbox. Now some say the Porsche 911 GT3 RS (42056) is actually a gearbox with an orange cover, so I thought I might as well attach it to the complete Porsche:laugh:.

 

Edited by Didumos69

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I got some questions for instructions, so I made building instructions in terms of a photo sequence for the compact stepper. I picked the version in which the shift lever and 90° limiter are separated. That version very nicely shows the two individual concepts that have been combined: 1) How the movement of a shift lever can be amplified with knob gears and 2) How a shift axle can be limited to 90° orientations.

This video shows the result of the instructions:

LXF-file of the result can be found here.

Edited by Didumos69

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Now that I have a photo sequence I thought I might as well share it on Rebrickable too. If you have the parts you should give it a go. You can feel a sense of rightness to it :wink:.

Edited by Didumos69

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Hi Folks,

 

I've seen the numerous threads on eurobricks.com which deal with improving the 42056 Porsche, which I really appreciate. I'm quite astonished how Lego could launch a set with so many obvious mistakes - but this way it's a big issue in modding.

 

Maybe you and the other Lego constructors can use the following llittle idea on your way to the ultimate playable Prosche.

I thought a bit about paddle shifting, and I don't like rubber bands, especially when they are visible. Furthermore, I intended to avoid any bulky mechanism and wanted to keep enough space for a steering wheel with inclined axle. It is very reliable and maybe could be improved for a HOG-application. Paddles can be attached easily – or everything you want. Also, it will be easy to mount a lever for backward-forward-motion or left-right-motion instead of the two paddles.

 

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=566384

 

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@Timewhatistime, that looks very interesting. I might just try this to feel how it works.

It would also be nice to see a short video showing its operation. I would like to see how far you need to move the levers/paddles for a single shift. Also, reasoning from your images I assume the levers with balls need to be pushed and not pulled or is that not correct?

I also rather avoid using silicon bands, but when you look at real mechanical applications there are so many that rely on rubber or silicon parts for smooth functioning. For example: an engine is mounted to a car using rubber rings and bands to avoid the engine from shaking the car apart. From that perspective I actually think that using shock absorbers for this kind of mechanisms is more odd than using silicon bands. But that's my personal opinion and does not take anything away from your solution being a very interesting one.

Edited by Didumos69

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2 hours ago, Timewhatistime said:

...

 

 

And you did use a rubberband though :tongue: ... But I like your solution using gravity, even if it doesn´t allow 10 shifts per second.

You should post direct deep links, then your pictures will show up immediately.

I had tinkled a lot with this stuff recently and installed the following concept above the rear axle / gearbox at my current chassis prototype. It doesn´t need any limiter, because the shifter tilts back and makes the knob gears rotate exactly 90 degrees. The T - shaped beam is the limiter and additionally prevents the red stopper get stuck when being kicked back. You need the blue friction pins at the stepper though, to prevent backlash.

 

640x327.jpg

800x426.jpg

Edited by brunojj1
LDD here: http://bricksafe.com/pages/brunojj1/stuff

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12 hours ago, brunojj1 said:

 

And you did use a rubberband though :tongue: ... But I like your solution using gravity, even if it doesn´t allow 10 shifts per second.

You should post direct deep links, then your pictures will show up immediately.

I had tinkled a lot with this stuff recently and installed the following concept above the rear axle / gearbox at my current chassis prototype. It doesn´t need any limiter, because the shifter tilts back and makes the knob gears rotate exactly 90 degrees. The T - shaped beam is the limiter and additionally prevents the red stopper get stuck when being kicked back. You need the blue friction pins at the stepper though, to prevent backlash.

Also interesting. What happens when you make only half a shift? Same question for @Timewhatistime. In my case that's where the limiter comes into play to make sure the shift axle either moves back or completes the shift. Just out of curiosity, what is the center knob gear for? To drive a gear indicator? HoG shifting?

Btw, your LDD-file seems to differ from your images.

Edited by Didumos69

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1 hour ago, Didumos69 said:

Also interesting. What happens when you make only half a shift? Same question for @Timewhatistime. In my case that's where the limiter comes into play to make sure the shift axle either moves back or completes the shift. Just out of curiosity, what is the center knob gear for? To drive a gear indicator? HoG shifting?

Btw, your LDD-file seems to differ from your images.

The system is not perfect as your solutions with rubber bands :wink: :thumbup:. But I´m quite satisfied with it because the intention was from the beginning to avoid any silicon bands. The opposite steppers kind of counterbalance each other, so that a half shift usually doesn´t happen. Anyway they happen sometimes when you shift while moving the car. Maybe I should install a white 24teeth clutch into the standard 4 - speed gearbox instead of the DBG to prevent damage to some gears :grin:... 

Sorry about the LDD not showing the same thing. It´s a kind of alternative idea, using an angled 3x7 beam as limiter, just to show the principle of solving the problem by using gravity only.

640x327.jpg

By the way, I hope you don´t mind us using your thread to present our ideas, not in competition, but rather see it as exchange of ideas. This way we can keep everything in one topic instead of making many singles dying too soon...

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59 minutes ago, brunojj1 said:

The system is not perfect as your solutions with rubber bands :wink: :thumbup:. But I´m quite satisfied with it because the intention was from the beginning to avoid any silicon bands. The opposite steppers kind of counterbalance each other, so that a half shift usually doesn´t happen. Anyway they happen sometimes when you shift while moving the car. Maybe I should install a white 24teeth clutch into the standard 4 - speed gearbox instead of the DBG to prevent damage to some gears :grin:... 

Sorry about the LDD not showing the same thing. It´s a kind of alternative idea, using an angled 3x7 beam as limiter, just to show the principle of solving the problem by using gravity only.

By the way, I hope you don´t mind us using your thread to present our ideas, not in competition, but rather see it as exchange of ideas. This way we can keep everything in one topic instead of making many singles dying too soon...

Okay, I get it. No problem to use this thread for this discussion, on the contrary. It's a good thing to share ideas thisway :thumbup:. I hope someday a shifter emerges that does not rely on any kind of elastic resistance :wink:

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Sorry, at the moment I don't have the possibility to make a video to show the operation of my mechanism. But because of the simple construction without any external frame, it should be easy to build it and test it.

I noticed that rubber bands get old over the years. And I don't like them - just like everybody here, as well. So I chosed the shock absorbers (brunojj1 will understand me). Yes, Didumos69, this is quite odd, I have to admit!  :-)

(But I don't have to hide in terms of oddity, when it comes to comparisons with the original 42056).

brunojj1 asked what happens, when you make only half a shift: Due to the 90°-limiter, which I just adopted, there will be full shifting or no shifting, exclusively. The crucial point is approximately pushing the balls 1 stud (no pun intended!). When you push them less, there will be no shifting. If you push them beyond this point, the 90°-limiter will make a complete 90°-rotation, which will result in shifting one gear up or down, respectively. 

 

Didumos69 asked how far the Levers with balls will travel to make one shift: It's about 2 studs - quite comfortable for HoG-Shifting, I think. Obviously, it depends on the length of the yellow L-shaped liftarms.

And: Yes, you have to push them. Of course, you can transform the pushing into pulling by some levers, if you like better. But for me, it appeared more comfortable to push when thinking of HoG-operation.

 

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@brunojj1 It looks interesting. Nice idea "splitting" and connecting both shifters with the central knob instead one axle connecting both XO liftarms. It saves a lot space when the knobs of both sides are placed in parallel. You have save my day :wink: and push me to make a car with a driver seat in the center because I failed to put my current shifter in the supposed Porsche 918 :laugh:(I managed to put the gearbox behind rear axle and the shifter system with the AWD behind seats but I failed connecting the shifter with the gearbox because it's far away and  the rear axle is in the middle. Going under the rear axle will introduce extra resistance and due limited space, creating a greater lever effect is not posible,  so it won't shift ) 

The only way to avoid ruber elements,  is making use of friction elements as Uwe did in the Porsche with two 8T gears 

Also I want to know if the red frictionless 3L connectors with the newest driving ring has less friction than using the smooth 2L connectors with the old driving rings

Edited by Jonfensu

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