Simplest automatic LEGO transmission in the world? Really functional. Principle explained.
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- เผยแพร่เมื่อ 31 พ.ค. 2021
- The video shows probably the simplest automatic transmission built from LEGO bricks. It is two speed transmission and uses a friction clutch. Shifting is smooth and the transmission is also used in the LEGO car, as shown in the video. It is therefore really applicable. A GoPro camera mounted directly on the car was also used for recording to see the change of gears while driving in slow motion video. I designed this type of transmission by myself and I have never seen any such simple solution. If any of you know or have seen a similar transmission please let me know. Extra simple LEGO gadgets are my hobby. I hope you enjoy the video.
- วิทยาศาสตร์และเทคโนโลยี
Finally a gearbox that doesn't need springs or elastic bands
Aren't the springs just inside the clutch? That does make it really compact.
@@voxelfusion9894 its just a friction type clutch
@@JSFofWT I presume you know the insides of that clutch, is there a image of the inside somewhere on the internet? If not, is it some type of compliant centrifugal clutch?
@@Positroni no it's just a bushing held in place with friction
@@JSFofWT well, bushing is kind of like a rubber band in this case
I’m simply amazed at what can be built using LEGO and also so impressed with the way an engineer’s mind works! This is very cool.
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Engineering is the best job on earth.
@@kaseycrooks5080yes
2:28 you broke my mind because its so ingenious but so simple. awesome concept!
Multiple differentials with power added in here and there are also the basis of tank transmissions. You don't want to put a brake on one part to make another part go faster, e.g. for steering, because that's wasteful of power, so instead you can use another diff as an input to vary things.
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Thanks for the detailed breakdown. One question, since the slipping gear is always slipping, do you sacrifice a lot of engine power?
It is slipping only when there is high load on the output. Of course there is some energy loss. Maybe thanks to big ratio difference between two speeds the lost energy in friction clutch is still not so big to stop the car.
nice job, could be done with planetary gears
There are similar-funtioning parts in some cars that do that called torque converters. There was an old car made in the 50s that had no gears and only used the torque converter which would keep slipping up until max speed. That car was infamous for being horrendously bad on gas mileage, down to only 5mpg or something. A big use for them is in drag racing where they'll rev the engine up to optimal torque/horsepower while the car remains stationary and when they launch that torque converter prevents the engine from detonating the transmission, and this is done to maximize launch potential. Bad for gas mileage but those types of cars aren't meant to be efficient, just fun lol
@@maebae5350 hydrodinamics ones, ¿right?
@@tomstech4390 Still better than anything I could come up with
i am speechless about this auto-gearbox its... unbelivable simple
GREAT explaining. I really learned something today. Never thought this would interest me, but it was soo captivating!
Thank you :)
This is way better than the idea I came up with as a kid. Mine shifted from 3:1 up to 1:3 via a centrifugal governor and just ground the gears until it built up the speed to shift. Seems to me I messed around with differentials too but that first one stick in my mind because I remember that once it got going it could actually outrun me. Good times.
Well done. I thought of something similar decades ago, but the Lego parts I needed to build it didn't exist yet; by the time the parts I needed did exist, I had moved on to other hobbies. Nowadays I wrench on purpose-built RC cars with tiny engines.
Very cool idea. I just wonder if that is kind of a magical illusion that looks right, but it works only because the car would also successfully climb the hill also without the transmission. Isn't there simply the extra force coming from the higher gear ratio "destroyed" by the friction in the clutch?
Hi Tobias, I have to say that this is very good question, I spent so many hours by tuning this transmission up that I even did not tried it. But I still have the car built so I just tried to climb some obstacles like small stairs (like 3-5cm tall), even climbing the car to vertical wall. Then I changed the friction clutch gear with a normal gear and the car was not able to pass some obstacles. The motor just stopped. So it really works well. Try to build it.
@@ferdoreznik Thanks for your answer, so all I have to say: well done ;-)
My first thought was also that instead of actually switching gears it just slows down and the rest of the energy gets lost to the slip gear. But if you say it works then it might be interesting to do the physics calculations behind it.
The biggest problem is that there is nothing really to hold the slip gear, so if there is enough resistance at the wheels it should just backdrive.
While it wouldn't be perfectly efficient, the efficiency could definitely be increased by lowering the slip gear friction and adding a backdrive prevention mechanism.
You definitely lose some of the motor power to the clutch gear. Can't avoid that with this kind of setup, which is why you won't see this exact setup on cars. (Something similar is used to switch gears in automatic gearbox, though.) But we care about output torque here, not the efficiency of power use. This setup won't produce as much torque at the same speed as a fixed gear would have, but it's still way more torque than you were getting out of high gear ratio setup, so it still works.
I’d imagine torque would be multiplied for the lower gear. If you think about it, the high gear is overdrive and when the clutch slips the ratio drops to 1:1, increasing the torque
That's just awesome! So simple yet so ingenious.
Should put one of these on an input shaft, speed it up or slow it down with gearing, then put another one. Should be able to get 3-4 speeds out of it with with different torque thresholds.
Finally a video as simple and educational as the old chevrolet videos
I am impressed. Thanks for sharing this amazing automatic transmission idea. I will definitely use this design and will pray for you when having fun. Awesome :)
Really cool concept and it seems to also have a small cvt component. However, transmission ratios are input divided by output. 2.33 would describe a gear requiring 2.33 input rotations for 1 output rotation. Likely just done backwards but in the automotive and industrial world its backwards which leads to a little confusion. Awesome concept and it would be cool to see more gears added in this way.
I imagine there's a range where the resisting torque on the output is high enough to cause the clutch to slip, but low enough that it allows the clutch gear to still rotate, effectively giving a range of variance in the output ratios. I think that this may actually be a CVT
I think so :)
Although it has two distinct ratios at each 'end', the 'middle bit' has some variability... So it's a 2-speed gearbox with a smooth transition between ratios.
Good call, well spotted :)
Replace the friction clutch with a magnetic clutch, and you could sell this in regular cars as a sealed CVT
Sadly this transmission doesnt work. You can get the same result using only the slip gear
That amazing explanation of transmission system
Hats of you 👍👍👍🙏
Excellent, best video explaining a Lego auto transmission.
Thank you Kenneth 😀 !
Lego has come a long way since I was a kid.
It is not only using 1:1 and 2,33:1 speed ratio but a large fork between both (we can see in a slomo white geer turning sometime). Very clever and compact. I cannot wait to see it on a train.
Thank you for sharing.
It is also not actually 2.33 to begin with. Gear ratios when it comes to transmissions are a ratio of input/output. 2.33 would actually be a slower gear. Look up ratios of a manual transmission found in a car or truck (or even an automatic) and see how 1st gear is usally 3.xx or 2.xx or similiar.
I see you've experimented with big trends in the past, but please stick with lego engineering videos! If they are as good as this, I'm sure your channel can grow.
I am so excited i saw diffential drive shaft in my lego insruction ,thats why i did test run
I like how you repurposed a differential to use as a transmission! Very cool outside the box thinking!
Thank you Josiah...
Excellent video with a great explanation and demonstration of how it works!
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Thanks for this cool video and the time you spent on explaining. Question: Does/ doesn't the friction gear wear out quickly in this construction?
There are iron plates pushing on plastic, I thin it will last some days, but of course it is just a toy. Important for me was to demonstrate that this way can work.
Good if replaced for a fluid clutch aka torque converter.
@@Bassotronics unfortunately Lego doesn't do one.☺.
@@CrusaderSports250
I made one one time with model team hubs and fan blades inside. It was filled with low viscosity corn syrup. Lol
I was 16 and a lil whack with inventions.
i rewatched this several times. It’s genius.
Thanks. 🙂
Very simple and functional.
This is a fantastic idea! It would be rad if they made a small self contained torque converter with a stator. It would be insane torque multiplication.
this looked like a video were a well known design was claimed to be revolutionary, but this was actually really well made, and well explained, this video actually wowed me.
Thank you :). Incredibe things are possible to be made of lego.
Very well explained!
Freaking awesome 😲👌🏼
Thats a beautiful and smart creation
Really clever! Nice and compact, simple, efficient. You can put more than one in a row as well.
Now this is brilliant!
Final a great design with even a greater explanation
Thanks for this idea in the moment i am building a crawler and this video hleps👍🏽
Very impressive. You could add something like a rachet to stop feedback under heavy load. Although I barely saw that happen in the testing you showed.
A more complicated version of just using the slip clutch alone, awesome.
This is fantastic! Great video!
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Simple, but does the job perfectly
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Awesome thanks for the Auto Transmission
So genius in its simplicity.
This is incredible!!!
Thats so cool
Great job man
Genius, SUPER GENIUS, greetings from Lima Peru
In particular range of load it behaves like gearbox. However, under the very high load: engine works, vehicle stops and clutch slips different direction.
I like the solution with the clutch/friction, as it enables smooth rotation speed change depending on load. It's great! Nevertheless, I prefer the friction between "gears" (like in planetary gear), when the minimal speed (the first gear) is limited by the engine power, not by gear clutch. Regards
Such a simple mechanism and better than every other automatic gearbox I've seen made with Lego.
And you know what the best part is? Every other solution I've seen involves gears grinding at least some of the time, this *JUST* works.
Thank you Tangent. Exactly this was my intention. Make something absolutely simple and working. Funny thing is, that many people dont believe that it really works... they thing that the car can pass the obstackles even on high speed and switching down is just illusion.. Because of them I made another video showing how it works. I made simple switch which disables friction clutch to show how the gearbox works only on high speed. Here.
m.th-cam.com/video/QBS1XcSwk_g/w-d-xo.html
Really nice man good job
this video is brilliant
I really appreciated the simplicity of the solution, much better than other solutions that require more pieces. I have actually applied your solution to one of my MOCs, my red station wagon, which is equipped with two L motors. But unfortunately the friction clutches (one for each motor) spin the opposite direction it should when stressed, probably due to the MOC's weight (850g)... I believe in my case each motor should get two friction clutches, but there's no room for this upgrade. Anyways, just sharing the experience, I'll apply it to a lighter model instead. Cheers!
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Very simple but awesome solution to a big question.
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Beautiful job.
God bless you.
that's a really cool little device, might have to build one now
I have been looking for this so long
Fantastic construction - and very well explained... thank you! 😀👍
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
This is a super cool design and is actually a fairly similar idea the Toyota Hybrid system uses (except obviously much more complex, being motor-generators rather than gearboxes and they can adjust to act like a CVT instead of a 2-speed gearbox)
It is fascinating, what everything is possible to make from Lego... 👍👍
It's compact and it looks to be efficient too! Very good job !👍🙂
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Thanks!!!!!! Now i can make an offroader that won't constantly go slow
Awesome videos, thank you so much for share.
This could be an excellent concept for a practical CVT in a car if: 1) a hydraulic torque converter is used instead of a clutch, and 2) a reverse gear is included.
thank you for explaining nice vid
Thank you for explaining and not just showing it.
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Brilliant!
Yes this is the right approach when you try to use a differential like a gear box, (in the lego world)
Extraordinary !
Thank you 😃
Very usefull! Thank you!
Thanks for this idea and clean explanation. Im just wondering, doest the friction wheel steal great amount of power while it stands still? Feels to me that the motor has to force through its resistance.
Theoretically, could you stack 2 of these for a wider range of speed? I'm assuming it would become slower but stronger
Cvt with legos
Technically yes
I never realized what the white gear was for until now
Very good explanation!
Freaking Legend.
Totally going to build this going forward. Much Appreciated.
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Such a good idea
this must be one of the best gearboxes ive seen on YT
That is the Best gearbeitet ever made
Nagyon jó ötlet!
отличная идея! будем использовать )
For a while I couldn't understand how automatic transmissions work, only after seeing a lego one I understand xD
And the Lego powerglide is born!
*”Let me explain you”* So cute 😄
Amazing!
For a basic automatic transmission made from lego, it is wonderful. I'm a little surprised that the lego makers didnt come up with it. Ir they haven't taken your idea and used it
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
Great idea! However I found that using two motors instead of the clutch works better. I used a non Lego product called Sbrick in order to shift manually via bluetooth. Using different gear ratios helped my vehicle pick up speed but still have the power to take off from a start.
Amazing job, truly a brilliant idea. However, I have noticed one issue that may come up. As explained, enough resistance will cause the gearbox to go into low gear, as it should, but if this resistance becomes strong enough, the differential in the gear box will begin to spin backwards (same direction as the input), because the output (wheels) could be stopped fully or pushed backwards (via the resistance). This would in turn cause the outer section of the clutch gear to spin in the opposite direction as the input. This would also lead to a situation none of the power put into the gearbox gets transferred to the output (wheels) and is instead wasted. I still find this design to be awesome nonetheless
in this situation the friction gear would provide a similar effect to the clutch in a limited slip differential, that is that whatever torque is required to cause the gear to slip is the amount of torque that would continue to be delivered to the wheels. Obviously not enough, but still not zero. It would be interesting to see another variation with two more differentials and a ratchet set up so that when the friction gear turns the "wrong way," i.e. the gearbox is stalled out, a low gear kicks in.
The first differential would block power output from the low gear using the ratchet when the friction gear is going the right way, that way the two gear sets aren't fighting each other. The second one would be used to branch in the power from the low gear onto the output shaft.
@@alexkelley8342 If I put this gearbox in a large and heavy lego car, would it cause the gearbox to stay in low gear constantly because of the weight of a large car?
Brilliant
This is the basic principle of the Voith DIWA automatic gearboxes mainly used in city buses. While stationary and at the beginning of acceleration, the engine's torque is fully transferred through the (internal, it's not seperate as with most gearboxes) torque converter and the lower the speed difference between engine and gearbox output the more this shifts towards the parallely operating fully mechanical 1st gear. At a certain speed difference the torque converter will then become almost completely needless and the fully mechanic 2nd gear is engaged. With this gearbox type, the torque converter is only functional in 1st gear and is disabled from 2nd (of the 2, 3 or 4 gears) onwards, but is used as a retarder, just to have mentioned this.
Very good
My friend made one of these when we were kids. He chained 3 together in series to have more gear ratios.
Some seriously clever engineering here for a fun Lego project!
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
i found yhis so use full it is copmact and doesnt use complicated pieces well done :)
AWESOME!!!
Very clever.
Nice idea :)
Nice explanation :)
Good job
it really work!
Btw the way you use the differential (and explain it) is similar to the concept of "power split device" used in every hybrid gearbox from toyota
Some old cars had an "overdrive" cruising gear that worked on a principle similar to this
This obviously works, nice gearing, but my understanding from tests and logic says: *there cannot be two fixed gear ratios in one closed gear system* So if it slips, every rotation of the output axle is possible. Obviously this burns some energy as it doesn't use torque to shift, but force x rotation = power.
But your great accomplisment: You modelled a local (higher) output torque maximum into the slip range. However, increase the breaking force on the output, it can always completely stop rotating, no matter how high the motor force is. Still kind of a good overload protection for the motor.
Yes you are right. It is also motor protection. And in extra high loading the clutch oscilates and it helps to overcome some high obstacles. Its interesting concept and after many tests I realized that it is great mechanism. Especially for its small dimensions.
Best innovation you can change the world good luck
Thanks 🙂
Dude, that was educational af -- subscribing for more like this. 👍🏻
I have build a even smaller automatic gearbox if you want you can check it out on my channel...
1:35 Minor correction: even when one of the outputs of an open differential is stationary, it still splits *torque* evenly. It's the power that goes to the other output.
Yes you are right in splits the power 50:50 all the time. But the rotation goes to one output only. that is important to understand that you can even combine inputs, not only split.