It's actually a continuously variable transmission, unfortunately it only has a range of 1:1-1.66:1, which isn't much of a range at all, I don't think it's worth the effort for such a small range.
An ideal transmission maintains power across input and output shafts.. Torque x Angular velocity.. As you downshift, you trade velocity for additional torque, and as you upshift you trade torque for angular velocity. There are many of these "dual differential CVTs" That don't work without intentionally introducing friction into the system, or adjusting the speed of a secondary shaft with what would require an electric controller and an additional motor. Even then, the transmission mechanism is in the controller and not the physical gear set. If you measure this system when downshifting, introducing the required friction into the system for it to "shift" will proportionately reduce the power curve of the system. You are essentially down shifting for no torque gain. You might as well be using a brake pad as a transmission.
I think the purpose of this is to adjust for a vehicle having to go up and down hills automatically, which would change the resistance on the output and this system would work. However, if you don't want to always be going as fast as possible then another system would be required to change the speed, as you suggest.
But what he said makes sense: you're not actually reducing the speed to get better torque, you are essentially dissipating energy on those 4 auxiliary gears.
It's not quite correct to assume you don't get multiplication but this transmission still has a problem. The only way this transmission can be in the "2nd gear" (where the differential casings remain stationary) is if the resistance of the outer gears is greater than the resistance of the load connected to the output shaft. In any practical application (e.g. a motorised lego vehicle) the amount of friction needed on the outer gears to enable a useful shifting point will be so great that you will be wearing out the gears quickly and wasting an enormous amount of power. Basically to get into 2nd gear the gears need to be as difficult to turn by themselves as it is to push the vehicle along! So even if you get torque multiplication, half (or more) of the power is dissipated as heat in the transmission. Either that or there is not enough friction in the outer gears and you will always be in "1st gear", never encountering a small enough load on the output shaft to 'shift' into 2nd gear.
No it doesn't, I tested it. When enough friction is added to make it "shift", it ends up directly putting more pressure on the motor and transmission. In the end it is easier to stayed geared higher than lower. Once again, "You might as well be using a brake pad as a transmission" - Tuc.
You are right. I built this transmission and the only time it's not in low gear is when it's driving on tile. Anything else, including carpet, will shift it into low gear.
MixZ Well... I guess that's the executive decision yall, Do ya'll hear that now? You must use new pieces when demonstraiting an idea here on UA-cam because this dude just declared that to be the facts and we don't want to have any inconvienent noises.
Car companies trying to make smoothest, fastest possible gear shifting by spending millions for research (except for ev's), while lego fans just using tiny bity piece of lego.
That’s not an automatic gearbox. You‘d only move things with the same speed. An automatic gear box would change the ratio if the input rpm gets to high. Here simply nothing would happen. No one needs to change the ratio if you don’t even use the power for anything
yes, but things would get weird if they all had the same ratio. This design leverages differentials and a mechanical tipping point - if every shifting unit had the same tipping point then they might not shift in sequence (one shift at a time as the load increased) and some of the small gears might fail
It doesn’t work as a gearbox, because it don’t has gear ratio change, and the torque is lost in the diferencial. Edit: I don’t noticed the differences between the gears in the sides.
This is cool, I built it. However, there are some problems with it that I think you should improve on. 1, it takes very little load to engage the differentials, almost eliminating the point entirely. It's really only good for road driving, but hit anything at all, the transmission kicks in. 2, the amount of extra torque it provides when the differentials are engaged is a little underwhelming. I tried putting a 1:3 Gear ration instead of the default but it ended up acting more like a slip gear.
That is bloody clever. For all the “how would you use this” , basically the vehicle would run in the top gear. Once the engine starts to strain it will then shift to the low gear and get more torque. Then once the strain is off, hopefully the drive will run direct through the Centre again at the higher ratio. Would like to see it in a Moc to see if that’s the case, otherwise the vehicle may need to stop and restart to engage highway speed.
If you added more stages and had a system for locking the differentials then you would have a really nice transmission without the need to actually switch gears like in traditional manual transmission. Automatic gearboxes that use planetary gears work in a similar fashion. Some parts are being locked to achieve optimal ratio.
This doesn't work for me. I've copied it exactly and the moment I put any tension on the output the difs just spin freely, can even rotate the output in the opposite direction.
It's a great device but not for cars, great for many other applications that need high speed when working at no load and high torque when resistence is met.
The reddit post that linked me here mentioned using it in cranes, so it's faster when just moving the hook and more torque when there's an actual load.
@Need2connect where would the power come from then? What I said was transfering power _to_ two output axles, _from_ one input. How would it transfer power _to_ the input axle, if that's where the power comes from?
I am wandering if this gearbox stay on high ratio just because of the friction of the low ratio gears (20 and 12 gears..). If yes: -> If the low ratio gears had almost no friction, the gearbox will switch to low gear anytime; -> the high gear has the torque of the friction of the low ratio gears.
is there a self-shifting system like this that either 1 doesnt use diffs or 2 doesnt require that power be sent through the half 12t gears? they all work but put one in anything bigger than a mini trial truck or connect anything but a pf mini motor and youll have some 6t gears all of a sudden... be nice to see a build that can take a bit of abuse. other than that, nicely done man! happy building!
Eric Bowling yes I know that, but the original is centripetal, centrifugal simply is a side word used by americans as it came from the machine called a Centrifuge. I was just saying that it is kinda an incorrect word that 'wiggled' itself into the Urban dictionary. . .
Wrong. Physics teachers tell you that "centrifugal force" isn't a thing because it simplifies teaching about centripetal/centrifugal forces. Centrifugal force is a real thing, and the difference between it and centripetal force is the point of reference. I don't know why you have to bring nationality into your flawed conclusion except that you are a pretentious non-American. And you do indeed seem pretentious, given that you feel the need to correct him over a non-issue like centrifugal vs centripetal.
bcuz it is not a gearbox. It converts momentum (by decresing rpm) to heat throught friction on the "gearbox"'s gears. It basicaly waste energy that cannot be transmitted to the wheels making sure that motor will not stop.
I built this device on my own, and it won’t work. The 12t single bevel gears don’t appear to mesh properly with the differential cases, resulting in MASSIVE friction that just stalls the motor when load is applied to the output. The output axle usually just pops out of the differential entirely.
At first glance I thought this too. Seemed like just an overly complex differential that didn't actually do much of anything. However when the output encounters resistance, it does in fact switch to a lower speed. Automatically.
@@ArcadiaCv lower speed and also lower torque because the torque just gets rerouted to the other gears. That's not the function of a real gearbox. It's function is to provide suitable torque. Reduction in speed is an unavoidable by-product, not the aim of a gearbox.
@@ArcadiaCv A real automatic gearbox does that. You are correct. But the one shown here in the video is absolutely useless. It's not transferring more torque to the output, when rotation is reduced. It's basically just a glorified brake pad.
awesome idea however it sounds slightly unhappy.
this comment is blessed
Lol
Slightly unhappy is the polite word for please Kill me. End my suffering
So cute words
that's the bevel gears in the diff, no problem there at all.
it´s so f****** simple. I would really congratulate you. it can be used in lots of places =D
best regards!!
It's basically a differential between a driven axle of a car but instesd of rerouting power to another wheel, it goes to a smaller gear ratio
It's actually a continuously variable transmission, unfortunately it only has a range of 1:1-1.66:1, which isn't much of a range at all, I don't think it's worth the effort for such a small range.
An ideal transmission maintains power across input and output shafts.. Torque x Angular velocity.. As you downshift, you trade velocity for additional torque, and as you upshift you trade torque for angular velocity.
There are many of these "dual differential CVTs" That don't work without intentionally introducing friction into the system, or adjusting the speed of a secondary shaft with what would require an electric controller and an additional motor. Even then, the transmission mechanism is in the controller and not the physical gear set.
If you measure this system when downshifting, introducing the required friction into the system for it to "shift" will proportionately reduce the power curve of the system. You are essentially down shifting for no torque gain. You might as well be using a brake pad as a transmission.
I think the purpose of this is to adjust for a vehicle having to go up and down hills automatically, which would change the resistance on the output and this system would work. However, if you don't want to always be going as fast as possible then another system would be required to change the speed, as you suggest.
But what he said makes sense: you're not actually reducing the speed to get better torque, you are essentially dissipating energy on those 4 auxiliary gears.
Tuc how do you know there's no torque gain? Doesn't adding any kind of gears add friction?
It's not quite correct to assume you don't get multiplication but this transmission still has a problem.
The only way this transmission can be in the "2nd gear" (where the differential casings remain stationary) is if the resistance of the outer gears is greater than the resistance of the load connected to the output shaft.
In any practical application (e.g. a motorised lego vehicle) the amount of friction needed on the outer gears to enable a useful shifting point will be so great that you will be wearing out the gears quickly and wasting an enormous amount of power. Basically to get into 2nd gear the gears need to be as difficult to turn by themselves as it is to push the vehicle along! So even if you get torque multiplication, half (or more) of the power is dissipated as heat in the transmission.
Either that or there is not enough friction in the outer gears and you will always be in "1st gear", never encountering a small enough load on the output shaft to 'shift' into 2nd gear.
No it doesn't, I tested it. When enough friction is added to make it "shift", it ends up directly putting more pressure on the motor and transmission. In the end it is easier to stayed geared higher than lower. Once again, "You might as well be using a brake pad as a transmission" - Tuc.
It's a good idea, but it would always be in the lower gear due to any weight within a build
You are right. I built this transmission and the only time it's not in low gear is when it's driving on tile. Anything else, including carpet, will shift it into low gear.
not if you added clutches a lot like a limited slip differential set up. then you could set the preload and how much torque it takes to overcome it.
Gear it down
What if you gain speed? Just asking
@@TomBom292 yeah thats how needing torque works
Very nice solution you came up with here......I'll use this for sure in my new MOC
Thanks for sharing
Would be good with two opposing motors, one large one for drive and the other providing the change in ratio effect + a bit more power.
Then the small one would get rotated unwanted under load as well.
"smallest gearbox"
lucasdynamics™ laughting in the corner:
i literally broke one of t he gears in the differentials by just rotating it the other way
Well then don't do that
The half 12th gears look likely to snap under higher torque imo?
I can see how it would be useful, but in the future please use newer pieces. I can hear the gears grinding.
BadAssXBox all gears are in good condition. The functioning of this gearbox relays on resistance between gears that's why it sounds like this.
MixZ Well... I guess that's the executive decision yall, Do ya'll hear that now? You must use new pieces when demonstraiting an idea here on UA-cam because this dude just declared that to be the facts and we don't want to have any inconvienent noises.
MixZ It is NOT usefull! It is completly useless because it uses friction to "shift" down and so there is not more torque in the "lower gear"
@@flo8735 that is what torsen does, and personally, I always wonder if could be done for torque conversion. Awesome
Car companies trying to make smoothest, fastest possible gear shifting by spending millions for research (except for ev's), while lego fans just using tiny bity piece of lego.
It might need a little lubricant but it was briliant transmission 👍
this is a holy grail, how to sensitive change torque with just gears
That’s not an automatic gearbox. You‘d only move things with the same speed. An automatic gear box would change the ratio if the input rpm gets to high. Here simply nothing would happen. No one needs to change the ratio if you don’t even use the power for anything
Exactly, it's more of a clutch that will only operate at very low output loads.
And here is another way to reduce the speed without augmenting the force/torque in the output shaft
For me it seems to work better if i only put the extra bevel gears on one side instead of both
so, if you put a few of these in a series would it be like having many gears instead of two?
yes, but things would get weird if they all had the same ratio. This design leverages differentials and a mechanical tipping point - if every shifting unit had the same tipping point then they might not shift in sequence (one shift at a time as the load increased) and some of the small gears might fail
Like the "Fell" engine transmissions.
It doesn’t work as a gearbox, because it don’t has gear ratio change, and the torque is lost in the diferencial.
Edit: I don’t noticed the differences between the gears in the sides.
Excellent in theory but XL motor just eats up and breaks small gears. Not usable for TTs.
That looks pretty torque sensitive?!?! >_<
- I may yet try it out -
DesignJunkie58 well, it seems to be perfect for medium engine's torque
Tailgunner088 Yeah, but what about a 2kg truck???
Very clever.
This is cool, I built it. However, there are some problems with it that I think you should improve on. 1, it takes very little load to engage the differentials, almost eliminating the point entirely. It's really only good for road driving, but hit anything at all, the transmission kicks in. 2, the amount of extra torque it provides when the differentials are engaged is a little underwhelming. I tried putting a 1:3 Gear ration instead of the default but it ended up acting more like a slip gear.
Nice idea. Too many cog interfaces to be efficient in a large scale application but still... nice idea.
This is a much smaller cvt design nice job.
That is bloody clever.
For all the “how would you use this” , basically the vehicle would run in the top gear. Once the engine starts to strain it will then shift to the low gear and get more torque. Then once the strain is off, hopefully the drive will run direct through the Centre again at the higher ratio. Would like to see it in a Moc to see if that’s the case, otherwise the vehicle may need to stop and restart to engage highway speed.
If you added more stages and had a system for locking the differentials then you would have a really nice transmission without the need to actually switch gears like in traditional manual transmission.
Automatic gearboxes that use planetary gears work in a similar fashion. Some parts are being locked to achieve optimal ratio.
This doesn't work for me. I've copied it exactly and the moment I put any tension on the output the difs just spin freely, can even rotate the output in the opposite direction.
It's a great device but not for cars, great for many other applications that need high speed when working at no load and high torque when resistence is met.
The reddit post that linked me here mentioned using it in cranes, so it's faster when just moving the hook and more torque when there's an actual load.
Sounds crunchy
is product ka naam kiya hai
It is nothing of a practical thing. Instead of increasing torque when losing speed it wastes it on the other gears disconnected from the output
great idea! have you already tested it in a moc?
not yet
very good
That's only a slipping clutch without any effect that a transmission has...
wut? why?, where?
Sorry, that's just an overcomplicated differential.
Bracken Dawson but an overcomplicated differential would transfer power to two separate axles, no?
@Need2connect where would the power come from then?
What I said was transfering power _to_ two output axles, _from_ one input.
How would it transfer power _to_ the input axle, if that's where the power comes from?
Thats a good idea
Thats a Like 😆
Clever idea
What piece is that the frame with holes?
I think is a 6x8 with Center hole
But... It's not a gearbox...
It is it is an automated gearbox
@Jeffrey Simmons oh ok
Jeffrey Simmons could you elaborate? It looked like it worked to me
I have no idea how this works, but good job anyways!
I am wandering if this gearbox stay on high ratio just because of the friction of the low ratio gears (20 and 12 gears..). If yes: -> If the low ratio gears had almost no friction, the gearbox will switch to low gear anytime; -> the high gear has the torque of the friction of the low ratio gears.
else?: ->
fast & furious gearbox
какие же было балдёжные технологии 5 лет назад и интересные...
This transmission destroys small wheels in the diffs
if you connect to two XL motor...
How could I make this more heavy duty
GENIUS
what does the extra gears the driving ring powers? does it generate mroe torgue so the car can go uphill?
you briliant builder, thank you for solution my problem.
c'est pas une boite de vitesse mais un blocage de différentiel automatique
It's a box with gears in it.
oui et non
Tried this it only seems to work with a motor
u basicly made a torque converter
is there a self-shifting system like this that either 1 doesnt use diffs or 2 doesnt require that power be sent through the half 12t gears? they all work but put one in anything bigger than a mini trial truck or connect anything but a pf mini motor and youll have some 6t gears all of a sudden... be nice to see a build that can take a bit of abuse. other than that, nicely done man!
happy building!
wonderful job!
nice i want one
Too bad it can only downshift! maybe someone will come up with a centrifugal transmission or something similar
centrepital*
Alphonse Hake world.honda.com/EV-neo/power/image/img_power03.gif centrifugal*
Eric Bowling yes I know that, but the original is centripetal, centrifugal simply is a side word used by americans as it came from the machine called a Centrifuge. I was just saying that it is kinda an incorrect word that 'wiggled' itself into the Urban dictionary. . .
Wrong. Physics teachers tell you that "centrifugal force" isn't a thing because it simplifies teaching about centripetal/centrifugal forces. Centrifugal force is a real thing, and the difference between it and centripetal force is the point of reference. I don't know why you have to bring nationality into your flawed conclusion except that you are a pretentious non-American. And you do indeed seem pretentious, given that you feel the need to correct him over a non-issue like centrifugal vs centripetal.
tralt135 >_
LMFAO I built and grenaded my gear to connect the two differentials but it's all good
@Flo that is what torsen does, and personally, I always wonder if could be done for torque conversion. Awesome
When you drive a 3 or 5 ton truck you know what it feels like
Thats just a torque convertor tho?
Crunchy
can you show it in a lego model?
Let me give you a suggestion, scrap this and create for disk brakes, one for each wheel.
Sounds like your transmission's about to go. Maybe it's just a solenoid.
That's basically a differential
Nice crestion. But it is awful! It doesn't work in car! Only slow gear works!
An automatic gearbox changes gear automatically.
This just stops when there is to much strain on the gears?
bcuz it is not a gearbox. It converts momentum (by decresing rpm) to heat throught friction on the "gearbox"'s gears. It basicaly waste energy that cannot be transmitted to the wheels making sure that motor will not stop.
this would be more like an automatic cvt great idea.
needs more rpm. i wanna here that thing get all stripped out
hear*
@@bernie604 her*
i couldnt understand where to use it?
Can u make it 4 speed?
thats less of a gearbox and more of a differential, theres no reverse gears or change in gear ratio
this is a holy grail, how to sensitive change torque with just gears
I built this device on my own, and it won’t work. The 12t single bevel gears don’t appear to mesh properly with the differential cases, resulting in MASSIVE friction that just stalls the motor when load is applied to the output. The output axle usually just pops out of the differential entirely.
Did somebody use it in MOCs?
How does it work? I can see how the gears in the middle work (Except for the two large ones.), but how does applying friction cause it to shift?
Thank you very much :)
toppp
nice and simple. ;)
All these engineers and designers talking about downshifting and torque and I'm just like...
o.o That's really cool. What is it?
But will it blend?
how to change gear
Using 2 drifentials
Now the real deal... are you ever gonna build a car out of all these parts
Super!
I don' know why, but it isn't working
nie wiem czemu ale nie działa
If I decided to try this, would you allow me to use it in a video? (credits would be given)
LEGOTechnic360 sure, INFO-ANARCHISM man!
A two speed automatic gearbox. Well done.
Gregzenegair Skynet what a nonsense!
По факту это автомат
this is gearbox or differential mechanism ?
this gearbox sucks I've build it and it doesnt work at all, with that motor I broke my lego PF L motor
it would work with old technic right?
ギアチェンジ的な?
Этож вариатор))
let us see it with that v8 of yours!
i am sorry but this is not an automatic gear box...
lazaros636zxr why?
At first glance I thought this too. Seemed like just an overly complex differential that didn't actually do much of anything. However when the output encounters resistance, it does in fact switch to a lower speed. Automatically.
@@ArcadiaCv lower speed and also lower torque because the torque just gets rerouted to the other gears.
That's not the function of a real gearbox.
It's function is to provide suitable torque. Reduction in speed is an unavoidable by-product, not the aim of a gearbox.
@@anujmchitale isn't that what an automatic transmission does though? They use fluid, but when the resistance gets high enough it initiates a shift.
@@ArcadiaCv A real automatic gearbox does that. You are correct.
But the one shown here in the video is absolutely useless. It's not transferring more torque to the output, when rotation is reduced. It's basically just a glorified brake pad.
What is this magic
nor really a gear!
nachgebaut hate aber graues nicht deswegen gröser
potet vettu