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Discussion in 'Life, the Universe and Everything' started by Jamira, May 22, 2018.
Don't use gears like this one:
Use something with sense instead. As I do:
I didn't. It was similar to the lower image. I think the upper image would have been ok as not complex. It was the complexity that broke FreeCAD. It couldn't handle the curves
Well, I remembered an old project. A gear drive with very special features. In the late nineties a customer asked me for a visualization of this project. His brother, resident of a local prison at this time, developed a supah-dupah gear drive with constant input rpm and either increasing or decreasing rpm output. Theoretical. At a sheet of paper. The customer wanted to get a patent for it. But that was pretty hard to get. Nobody could imagine if this idea does really work. It was hard to fund a functional prototype. So the customer was in need for a presentation to win investors. That was my part. I made several videos with 3DS Max. I don't know what happened to this project later. My thought was: It won't work as expected by the customer.
How ever. In the past the main problem was to realize a functional prototype. And lately I thought by myself: Hey, just print the parts and try it. I imported my old 3DS Max model to Rhino:
Can I be an ijiot and ask what you mean by constant input and either increasing of decreasing rpm output? I guess specifically, where is the input and ouptut above? and what causes the output to be increasing or decreasing? Increasing/Decreasing from what to what?
If I understand it right the idea is a CVT or something similar. Only few cars ever had a gearbox like that, but where it's useful is for machines that are driven by a combustion engine but need variable output speed. Combustion engines have actually only a narrow interval of rotation speed where they are most efficient.
Aircraft do that by changing the pitch of the propeller (basically changing the tooth count on the gear grabbing the air) while the engine rpms remain the same, however I have a hard time seeing how that can be done with physically touching gears.
I have trouble understanding how that model works, but it looks like just a series of planatary gears? If that is the case you would have a set ratio increase or decrease ratio in rpm, but I don't see how it could be variable.
LOL! It's cool, isn't it? Here is another picture:
Left is the input, right the output side. The purple elements are couplers and can be moved independent from each other right or left to produce different effects. Either even or de- or increasing speed at the output. That's the theory. As mentioned I doubt it will work. At the other hand: I'm unable to imagine what will really happen. This fact makes me angrily. And I just want to try it. Today it's easy and cheap to make the necessary parts.
The final gear drive should look like this:
Ok, if purple are the only adjustable couplers........
Starting from the left,
first coupler selects output to the orange shaft between the green or blue inputs.
Second coupler selects between the light blue or orange inputs output to the yellow shaft.
That gives you 4 different gear ratio options between the starting power source and the yellow.
still not sure whats going on inside the yellow box, nor can I tell if the light blue axel from the starting input is the same as the light blue inside the yellow box.... the more I look at it all the more confused I get :P
for example the very first thing, two sets of gears driving two sets of gears with apparently same gear ratio between the originating light blue shaft and the parallel pea green shaft, why two sets of gears there doing the same thing?
ok figured out there were two different gear colors starting, just looked similar, I numbered the different speeds I think I see up untill I think it gets bound up......
the light blue shaft running into the center of the yellow box drives the planatary gear output to the orange shaft, however the yellow box at a different speed is driving its own planatary gear to the orange shaft as well, if there is not a disconnect there somehow I think the light blue and the yellow both driving orange will bind up?
First half of the mess has two ouputs, either yellow or light blue(origin rpm)
There has to be selection possible in the last half, but I still cant see whats going on, are there disconnects there somehow?
LOL! It's 20 years ago and I can't remember details. But I still have one of the final videos:
But what I know is that a given set of gear-wheels will produce exactly one transmission ratio. Planetary gear or not.
I assume at the output side will happen nothing. Either all this gear-wheels block themself or enable a free rotation without effect to the output side.
Here is the plan:
ok I see it....
Two inputs into the second set, either light blue or yellow, the other is free.
Option 1, light blue is engaged, it powers the final orange shaft through the grey and then green gears in a planetary system.
Option 2, yellow is engaged, it powers the final orange shaft directly through the grey gears and spins in the opposite direction than the blue because it goes through 1 set of gears instead of 2.
The yellow also runs the red gear, which either does nothing, or binds up the final shaft, perhaps it is supposed to be selected between those two outputs from yellow?
Edit: no im wrong again..... light blue can not be disengaged as it is the original source of power shaft.....
Sorry posted as you were posting and didnt see your diagrams,
I see the idle, increase, same, and decrease, but that is all to the yellow output and doesn't need the second set of gears to accomplish. is the second set just to select between left and right hand rotation?
I started in Rhino with real gear-wheels already:
I like to play around with such steam punk issues ;-) Let's see how far I will come!
I have no clue, Narfi - LOL! I don't even know if anything will rotate in this gear-box.
is the light blue shaft in the second set of gears a solid part of the power input shaft? or are they just a similar color, I cant tell...... If it is the same, then I am pretty sure it will bind up, if it is a free floating axel shaft for the next set of gears then it might not.......
I use other colours in Rhino. But the yellow highlighted red part is the light blue part in the diagrams
Btw. I found the original drawings I got from my customer:
Ok, that shows 3 selectors. It also separates out that second set of gears into two different sets making it 3 total sections of gears.