hey guys, thanks for all the positive comments
Elliot wrote::D
Hey Carmatic, welcome to the discussion!
This will take me a while to digest.
But I am VERY interested in your ability to invent new solutions in the realm of gearing. You see, I have a "holy grail of gearing" problem in front of me, which I have still not solved. So prepare yourself to be recruited! :lol:
Continuously Variable Transmissions intended for bicycles... we have. NuVinci, by Fallbrook Technologies. 0.5 underdrive to 1.75 overdrive. I'm running two of them IN SERIES on one of my Kinetic Kontraptions.
To be continued.
:D
interesting,
0.5 to
1.75 gearing?
c would then nominally have to be (0.5)/2 =
0.25, and
d be (1.75 - 0.5)/2 =
0.6125 , to ensure that the wheels can turn both ways at equal rates... like the reason for
c is to make the differential gear stop at the CVT's minimum ratio, and the reason for
d is to provide half of the maximum output speed of the differential...
i guess choosing a ratio of 2 for the gears has the added advantage of simplifying the calculations, since differentials output the average of their inputs...
if the exact gear ratios arent available, i guess you'd round it up to get a forward bias... or you could add a greater amount of forward bias to it too, depending on what you want, if you increase
c such that its possible to get both the concentric gears turning in the same direction, you'll have abit less friction from the planetary gears, but it willl essentially be like a form of overdrive , in the sense that your only likely to use it when there's almost no resistance on the pedals and your leg muscles cant move any faster...
also, you are running one CVT after another? arent you worried about torqueing out the one down the line?
motskyroonmatick wrote:Wow Carmatic!
When you bring a vehicle to the playa-- I definitely want to check it out.
Now you have me thinking about making the pedal powered golf cart I am working on dual powered. --WIND--
BTW I recently drained the gear oil out of my club car transaxle replacing it with 5-30 motor oil to reduce oil drag. I noticed no improvement but hopefully in ways that are not measurable by feel there is an over all improvement.
Now on to looking for vertical axis turbine designs for inspiration. :)
im glad that you took up the VAWT idea, i first saw it on youtube videos... they make pretty neat decoration too, the horizontal visibility of their surfaces mean that you can paint them to blend right in with the decorations.... that and their mechanical simplicity make them ideal for festivals
imho, there's different types of drag that i know of.... one is viscocity, which increases with speed, think putting your hand out of the window of a moving car... the other is thixotropy, which would probably apply more to greases, it gives way once you force your way through it, think gummy substances like dough...
at the speeds of human pedalling, different viscocities wouldnt matter too much, but different thixotropic values, which normally dont matter under engine power, becomes very apparent... its all under the study of rheology, something im not too fussed about...
Tiahaar wrote:Impressive transmission Carmatic! And welcome from me to the boards also! Yes I agree with Elliot, this looks like a novel way to get differential steering, that is varying the amount of power by some means that is diverted to each side of the drive wheels/tracks. Are you planning a vehicle build? Keep us posted here!
As a side, the former TerraKrawler is about to loose its tandem pedaller attachment (going to a new KSR project). I still think that it is a workable machine, just needs more horsepower...like say a donor 12horse riding mower engine? Heaven knows the 2080 chain could take the output!
unfortunately, im not in a position to do any building... i dont have the space, i dont have the tools, and even if i had, i dont have the skills to use them...
to think, all the infinite dexterity of human hands, and all we're doing most of the time is pushing levers, turning cranks, and pressing buttons...
technically, the power , as calculated by multiplying the torque and the rotation rate, is constant to both drive wheels all the time...
so, intinuitively , the harder it is to move, the slower the vehicle will do so...
but as ironic as it may seem, moving in an environment which usually calls for more rigorous pedalling, would instead mean more delicate controls on the CVT's, lest you stall yourself out or move in the opposite direction...
the chain has an operating envelope between snapping from the torque and tearing itself apart from the speed, i guess you should be allright as long as you keep it geared between these two extremes...
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the only real concern with my transmission is if the CVT's give out after the vehicle has taken you deep into the middle of nowhere... thats why i chose a ratio of 1 for the CVT input, any lower and the torque might cause it to slip and wear out, any higher and the excessive RPM would overheat it or something
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and i really think that adding width to the tracked vehicles is a good idea, so i'll bring that point up again...
assuming that you have one track stopped, and the other track driving... the vehicle would turn in a circle, centered on the stopped track...
the cleats on the stopped track would experience pure sidways motion, with it getting more severe towards the front and rear ends...
the moving track would trace out the outer rim of the circle, and its cleats would also experience some degree of horizontal motion, but its not as great as those of the stopped track...
the further apart the tracks are, the closer to a straight line the moving track will travel in... this would reduce the sideways motions on its cleats, and there will be less friction... also you will have a greater leverage to overcome the friction of the stopped track from...the 2 factors add up, so a little added width would have a big effect...
but you shouldnt go easy on the reinforcements against the side loads, tho, since your vehicle will turn both ways, and whichever track is slower/stopped will have the greater/greatest side load respectively...
current moon
