[WIP] Rotary Pneumatic valve

[Tommy Styrvoky]

WIP rotary pneumatic valve by Tommy Styrvoky, on Flickr

WIP rotary pneumatic valve by Tommy Styrvoky, on Flickr

This is an idea that I have thought of when designing LPEs, it is currently sized for 3 4mm OD*1mm and 2 9mm OD*1mm o-rings. There still is a lot of work that needs to be sorted out with it, right now I am using 0.1mm clearances, though I suspect I may need to tweak some fittings for the location of the peripheral o-rings to seal, though not provide too much friction on the core of it, maybe increasing to .15 clearances, though I don't want it to be too loose.

Another issue I need to sort out with the core of it is the distribution of air, currently the valve only distributes air to the 0° and 90° positions, I need to figure out a method for routing air on an offset of 180°. there is also no exhaust port mounted on it either. One of the advantages to this system, it would be possible to create offsets on the core model  for 120° and 60° crankshafts.

cross section, all of the air pathways are 1.5mm in diameter.

WIP rotary pneumatic valve by Tommy Styrvoky, on Flickr

 

 

Edited July 24, 2018 by Tommy Styrvoky

[Tommy Styrvoky]

I fixed the 180° distribution, not perfect as there is a point in the cycle where both cylinders are extended, though a solution. I could see if it would be possible to install a check valve in the middle tee part, that would fix it. I may also see about increasing the elapsed time of air release to each of the ports.

Edited July 24, 2018 by Tommy Styrvoky

[MangaNOID]

this is nice, I guess there is a specific application for this that you have in mind?

[Tommy Styrvoky]

3 minutes ago, MangaNOID said:

this is nice, I guess there is a specific application for this that you have in mind?

For LPEs, as it would eliminate the need for valve linkages, and potentially improve performance because of less friction.

[Imanol BB]

Hi Tommy, i must say this is a very interesting design you are making, this would make pneumatic systems much more compact, as you say, i see there are not exhaust ports, but that could be solved easily, by the way, what about using the first design of the core, but put another air path in the opposite side of the core?, i made an small sketch of this, the round black part with the green paths is the core with the opposed air paths, the blue would be the air inlet port, the yellow the outlet ports and the red would be the exhaust, which could be just a hole in the bottom part of the valve:

in this case, 90 degrees of rotation change the air flow from one port to the other, and at the same one port supplied with the pressurized air, the other one has a path for the air to exit; i saw this design in an explanation of how an hydraulic system operates, and it might be helpful for you; all in all, the valve you are designing looks surprisingly good, and i hope you can achieve your goal in a near future, i'll be looking forward to more updates, thanks for sharing it with us.

[MangaNOID]

 

sorry for the bad pic but is there room to slightly offset the holes so a pair only matches up with one outlet? holes should be 180 degree apart unlike in the pic of course.

 

EDIT: Imanol suggestion seems far better! 

Edited July 25, 2018 by MangaNOID

[Tommy Styrvoky]

I thought of both of the above mentioned solutions, though both have there pros and cons, I will see about printing some of the valve parts when I get back to college, as it appears Shapeways has some issues with a couple parts of it, I could see about printing it in the white plastic, though it would end up costing $7 each i could for sure get the detail I wanted in the resin, though it would be brittle. Also I haven't looked too much into sourcing o-rings(... guess if I do order them, it will be like 50), though that may be a challenge for the 9mm ones. Otherwise, I may want to check some details about part clearances with @efferman, as I have only had experience with printing a couple models on their site. Because of this the part needs to be dimensionally accurate to rotate smoothly, and seal correctly. I didn't decide to add another o-ring on the bottom, as that seems redundant because of the exhaust, though if necessary I could add one.

Rotary valve by Tommy Styrvoky, on Flickr

 

As seen when previewing from Simplify3d, there are a couple gaps that need to be fixed, though mostly the important parts look ok to be printed in PLA.

Rotary valve by Tommy Styrvoky, on Flickr

Edited July 25, 2018 by Tommy Styrvoky

[MangaNOID]

Is this more for power functions in your thoughts or manual operation as well? Now probably both of course, but have you considered an elongated teardrop shape lead in/out of the ports on the rotary section to be able to have control over the speed of the air (thus slower piston response if needed). This would mostly only benefit manual operation but I would consider this a desirable addition.

It’s your design you have in mind of course but if your open for other suggestions. Its kind of all or nothing with current valves unless your very dexterous or gear the new axle shaft type down a lot.

EDIT: sorry this is all redundant comment as I just realised what LPE means. Sorry.

Edited July 26, 2018 by MangaNOID

[TechnicRCRacer]

Are you going to print it soon? I would be interested in a video.

[AFOLegofan66]

This looks very promising. I like the idea and will enable much smoother air transitions in many different Mocs. Would you ever have this available on Shapeways one day?

[Tommy Styrvoky]

55 minutes ago, AFOLegofan66 said:

This looks very promising. I like the idea and will enable much smoother air transitions in many different Mocs. Would you ever have this available on Shapeways one day?

I will see, though I will print it first with a FDM printer, as it is much cheaper to fix mistakes with the model, as there may be a rather  long revision process to make it seal air. You may want to look into the new pneumatic v2 switch.

[Aventador2004]

Nice work so far tommy! This is a very nice idea so far. 

[kieran]

Nice, would be very a good addition to the current line up of valves 

[LegoEmbodiment]

Great job!

Here are my ideas:

https://youtu.be/NJYXYrzyKaI

https://youtu.be/qERxeuFJYyU

https://youtu.be/bAhiUYXrIl4

[LegoEmbodiment]

Where can that small o-ring be found?

[Tommy Styrvoky]

1 hour ago, LegoEmbodiment said:

Where can that small o-ring be found?

I found links for it on McMaster Carr, though there are many other retailers, you just need to list the sizes 4mm OD*1mm. this site is a rather good reference for what is available, as this is useful for when designing the parts.  Shipping costs from that site is rather expensive, and it is rather easy to do a quick search for the specified O-ring size and you will see it is rather cheap to get a set of 50 o-rings for only a few dollars. 

a list of o-ring sizes here https://www.mcmaster.com/#o-rings/=1dycueu

And maybe a suggestion that would make your life a lot easier is to use polystyrene sheet and tubing (maybe brass tubing too) to build up components, as that would require less work than modifying existing lego parts. 

This may be a good place to start, looking for supplies. https://evergreenscalemodels.com/

Edited July 31, 2018 by Tommy Styrvoky

[LegoEmbodiment]

Thanks

[NullCube]

I'd hate to be a thread bumper, but I'm really interested in this.

Has there been any progress made on this rotary valve? I would really like to have something like this in one of my projects, is there a file I could download of even just the WIP valve? I'm not asking for anything that works, just maybe something that I could fiddle with?

Thank you so much!

[Tommy Styrvoky]

16 minutes ago, NullCube said:

I'd hate to be a thread bumper, but I'm really interested in this.

Has there been any progress made on this rotary valve? I would really like to have something like this in one of my projects, is there a file I could download of even just the WIP valve? I'm not asking for anything that works, just maybe something that I could fiddle with?

Thank you so much!

I got a little busy with college, maybe some day I will print it. Though here's the current progress from the last update. You will need Fusion 360 to open it, this program is free for makers and small businesses. 

[TechnicRCRacer]

9 hours ago, Tommy Styrvoky said:

I got a little busy with college, maybe some day I will print it. Though here's the current progress from the last update. You will need Fusion 360 to open it, this program is free for makers and small businesses. 

Thanks for the f3d file!!

[NullCube]

10 hours ago, Tommy Styrvoky said:

I got a little busy with college, maybe some day I will print it. Though here's the current progress from the last update. You will need Fusion 360 to open it, this program is free for makers and small businesses. 

Thank you so much!!