One thing I'd like to see would be the same car chassis trying to navigate the same obstacles, but with a basic transmission, just to get a frame of reference for how the continuously variable transmission is actually solving a problem that the basic transmission would simply fail at.
Yeah, that's a great idea. It could've been cool to show a side-by-side of the two cars going over terrain or pushing objects. If I make a similar video in the future I'll try to include something like that.
I’m not sure this is a CVT, looks like an automatic transmission to me. In theory, if the design for a CVT is very low friction, it would be by definition more efficient. When hybrid vehicles came out they decided the small increase in efficiency was worth the significant increase in cost.
im curious about this as well. ive seen a lot of cvts like this on youtube and for my feeling the extra torque generated by this is wasted on fritction, and in the end you could better hook up to engine one to one to the wheels for the same result. i would love to be proven wrong about this!
I’d say this is more similar to a torque converter and not a cvt transmission. A cvt will basically change the gearing by changing the size of the pulleys that the belt connects to. A torque converter will slip and different amounts to create more or less torque. I hear that the motor was struggling under load. A cvt is nearly 100% efficient so if it was a cvt it would not struggle like that. Instead the pitch of the motor would stay the same and would just lift the load slower
This isn't an actual CVT, the ratios between the two pulleys aren't actually changing. Yes, the second pulley is moving slower, but that's just because the belt is slipping. Any gain in transmitted torque can be explained by a combination of the extra tension pulling the rubber band into the secondary pulley plus localized heating of the rubber band at the point of contact generating more grip, plus the momentum of the primary side dragging it a little harder in pulses.
Love the idea, I would instead reverse the transmission to make your creation go faster! Torque is a good way to show how it works, but if you can make a lego car that can go from snail to rocket that would be awesome!
Thanks for the suggestion, but the transmission has to go this way so the output torque increases when the car encounters some resistance. To make it to go faster, I could just increase the gear ratio to the drive shaft, but I chose this speed so it would have enough torque to climb the slope and push the book.
@@matthexkt8409 look it kinda does the same the non load speed would be top speed and the lowest speed would be first gear. when a car wants to go it has to overcome friction so it needs more torque at first but then the load slowly decreases so in a normal car you can go to a higher gear and this will also do that because it needs less torque so it speeds up the only difference is that with a car its not based on torque but on engine rpm
@@cuberznl well, you always can do such high rpm and low torque on input shaft, that car cannot start movement before it lower the gear in CVT. The you'll get what you want: slow start, gradual acceleration, high speed with no obstacles.
This is a great representation of how to do science correctly, that it is quantitative and the results from data is how we end up in a conclusion. Great job!
@@BananaGearStudios except the conclusion is completely wrong! the torque output is not increased by introducing slipping rubber bands. Do the experiment without the bands and you'll see...
I can't believe how far we've come in the world of lego CVTs. It was only a few years ago that a small scale prototype was almost impossible, now we've got this.
A real cvt though uses a cone shaped pulley that moves and a v- belt. You change the distance between the cones to increase or decrease the size/ ratio.
Hub van Doorne would have loved to see this, my Volvo has a continuously variable transmission. Keep up the good work, this might become a (LEGO) technically very interesting channel!
I have an old Daf 66YA with CVT, a Mercedes A class with CVT, and my mum has a Nissan with CVT. That's probably why I was hoping this would be a video about an actual CVT, not about something that kind of produces the same result as a CVT.
@@GuusJanssen indeed, it is absolutely NOT a CVT. The CVT in your car actually DOES increase output torque by reducing the gear ratio. This LEGO device simply introduces slippage.
So what do the red gears do? I now have a basic understanding of how this transmission works, but first showing of their function would make it more clear.
I still don't understand the whole concept. Maybe if you read this you would be nice enough to explain how the gear ratio expands just by the rubber band slipping 🤔🥲I can't understand it
Why did you underdrive the pulleys, relative to the other input to the differentials? If you had made the pulleys spin at the same speed as the other input (or faster), then you would have had a wider gear range, per stage. Would that have been too much torque on the system? Or melt the bands?
idea for another video combine all such conveniences into one super off-road car for remote control if you make an automatic gear box + this and a few others, it could be interesting
The differential gear ratio in your car at home is likely to be somewhere around 2.42 or 2.73. Your automatic transmission multiplies this by using various gear ratios around 3.06 - 0.7.
For larger engines maybe. A lot of fwd cars are utilizing things more like a 4.11:1 or in some cases I'm aware of, a factory 4 cylinder car with a manual trans and a final drive ratio from factory of 4.56:1 an this is not uncommon. Gear ratios like the ones you listed are more commonly found in pickups, especially with the more common use of high gear count automatics with multiple gears actually being an overdrive ratio like you listed. The ratios transmissions tend to use seems to be a pretty accurate range.
@@goosenotmaverick1156 Additional info is appreciated. As you suggested, I'm used to 5.7L V8s. Specifically Chevrolet. Addendum: I do not own a pickup truck.
@@frikyouall I knew where you were coming from. I grew up a die hard GM kid and got into Hondas and have learned everything in between and beyond that I can get my hands on. I see a lot of different stuff from kei trucks, motorcycles, to 2.5 ton trucks and tractors. You were pretty spot on with the other ratios. Props on that. Why familiar with the GM (likely vortec or the older TBI setups? Maybe TPI motors) but not having a pickup? That's where I find most of the 5.7L familiar folks. Killer engines, killed by stringent emissions requirements.
@@goosenotmaverick1156 I never really liked pickups. Prefer to be on the ground with a better center of gravity. Just personal preference. I have '75 El Camino (truck, but not a pickup) that I swapped a '79 RV motor into out of necessity, and a '94 Roadmaster that probably needs a new Opti. So an A-body and a B-body. Looked into putting a 700R4 into the Camino a few times, but settled on the stock TH350 for towing, and am considering a 3.42 or higher posi for the rear. Basically, I spend a lot of time playing with gear ratios. Not as much as the Lego guy, but still a lot, I should think. I started with a Honda, but it wasn't until I got an AMC that I cared enough to learn anything. When everything needs to be replaced or rebuilt, you tend to start paying attention. So you have my respect for learning while you had the opportunity, and not out of necessity.
Just discovered your channel, and as one who also likes legos and gears and mechanical things, youve earned a new subscriber! A new gear to your machine :) ⚙️
Interesting concept. Personally, I think having a much greater gear ratio difference within each stage of the transmission might be a good thing, but I don't really know if that would work with the current design. Additionally, I think the highest gear ratio seemed a little high. In the basically no-load scenario, the transmission has a ratio of 6.06:1 which is quite deep. A typical car transmission has a first gear ratio around 3.6:1 or so, and the highest gear ratio is either ~1:1 or even an overdrive, 0.8:1 or so. However, if we took the base ratio of your gearbox to be a 1:1, then the maximum gearing is actually only 2.2:1 or so, which is roughly second gear for a car. What I suppose I'm saying is that I think the transmission would be more realistic if it actually had a larger range of speeds. Using the percentage measurements you gave, a normal car transmission would have a range of about 350% or greater. I suppose this is coming across somewhat negative. On the contrary, I think it's a very interesting design and not something I'd have been able to come up with. I guess I was just hoping to see something more like a truck transmission, and a test being it having to accelerate a heavy vehicle up to speed. Oh, and one other note. Some of the scenes in the video are a little slow, and I think some background music would really help. You could try it out and see if it boosts viewer retention. And I just realized you're a super small channel. Honestly I thought you were a relatively big channel with a couple thousand or tens of thousands of subscribers. Keep up the good work, and I think your channel will grow pretty fast.
Thanks for your comment, lots to think about! Regarding the gear ratio range, I remember testing out a few variations of the design, and it worked best with each stage of the transmission having this gear ratio range, so the only way to increase the range would have been to add more stages. I actually considered that, but thought that three was enough to showcase the principle of the design without it being too complex. Getting it to accelerate a heavy vehicle is a great idea though. About the background music, I quite like the style of just listening to the sounds of the pieces and the motors, but I'm open to adding some background music if I think it suits the video.
You forgot to factor in final drive ratios when you were comparing to ratios in cars. Ranging anywhere from the high side of 2:1 all the way upwards of 5:1 or a bit higher depending on the application. And that's applied after the ratios within the transmission are applied. So a 3:1 ratio, PLUS the ratio of the final drive let's just call it 4:1....
I wonder if you could use a worm gear instead of a ratchet to create a sort of one way "torque valve", while still allowing the motor to turn the diff in reverse. Also you should use a clutch gear instead of slipping a rubber band.
??? You can do the same thing in a car by slipping the clutch. You can alter input/output 'gear ratio' all you want, but there are huge friction losses until the slipping stops.
Thanks for the comment. As far as I understand, a slipping clutch will increase the gear ratio, but not increase output torque, whereas this design uses the slipping belts to alter the gear ratio through the differentials, resulting in higher output torque.
@@BananaGearStudios There is NO variation of gear ratio in your setup whatsoever! All there is, is slip slowing down and weakening the output and wasting power by converting it into friction and heat instead of driving the output shaft.
I wonder how it compares to just a single gear reduction of the same unloaded ratio? As it would be a nice way to see how much efficiency is lost through the slipping, as I'm sure there are some losses associated with that.
people seem to have no idea what a CVT is about. Ofcourse you an change the speed of the output of a differential if you put a variable brake system on the other side. Bit that is far from beeing a CVT.
Couldn’t you do this in a car, by utilizing a torque converter as the “slipping pulley” part of the system? This would overcome the CVT’s main problem in modern vehicles, that they aren’t that good for high torque applications.
You could and if you did then you would only be wasting fuel and reducing the torque output of your motor compared to a conventional transmission, just like this useless Lego setup does. Compared to a conventional gearbox with the same gear ratio this setup effectively only makes the motor WEAKER, not stronger!
@@tomwoggle9411 this doesn’t answer my question. I’m asking about improving the current CVTs that already exist in the car market today. I know CVTs aren’t as efficient as a traditional geared tradition. Care to actually answer my question.
@@ATTACKofthe6STRINGS I did answer your question. All a slipping pulley 'achieves' is massive wear and friction loss. It's practically just like driving around with a constantly slipping clutch. Neither a slipping belt, nor a slipping clutch increase torque output in any way or form, in fact they REDUCE torque output and waste fuel by generating heat instead of propulsion. Aside from imperfections a CVT alters the gear ration and does NOT slip. It commonly just has slightly higher losses than gears do, but it doesn't nearly generate as huge losses as a slipping clutch or slipping belt drive do. I'm sorry to bring it to you and to bust your bubble, but your 'brilliant' suggestion of doing this slipping belt drive in a real car is really just stupid and that is why no car manufacturer does it. It's not like belt drives and clutches (slipping or not) haven't been around for well over two centuries by now. If a slipping belt drive somehow magically really changed the gear ratio and did what you think it does, wouldn't you expect it to be a standard application ever since steam engines were used with belt drives in the 18th century?
@@ATTACKofthe6STRINGS In fact I did answer your question. You obviously just didn't fully understand what I commented or you weren't able to fully comprehend the consequences of my explanation on the complete and utter uselessness of your suggestion. A slipping belt drive, just like a slipping clutch does NOT increase torque output of an engine. It also does NOT change gear the ratio which a CVT transmission does! CVT transmissions aren't designed to have a lot of slip (some CVT designs, especially those based on torque converters do have minor slip, but only by a few % which isn't nearly as much as a slipping belt drive shows) All a slipping belt drive really 'achieves', is to REDUCE torque output and waste fuel by generating massive wear and lots of heat via friction. The only way this slipping belt drive can actually be useful is by either functioning as a kind of clutch or by functioning as a torque limiter, so more or less as a safety feature. If your 'brilliant' suggestion of using a slipping belt drive instead of a CVT would actually work and had any benefits, then it would have long been a standard application in vehicles and machines. It's not like belt drives (and the problems around slipping belt drives) haven't already been around for long over 2 centuries by now.
Great question! Looking at the results tables, the number of output rotations stays fairly constant for each weight, corresponding to the fact that the weight moves roughly the same distance, as you said. However, the number of input rotations increases across the tests, resulting in the gear ratio increasing. You can see the changing gear ratio because the weight takes longer to be lifted the same distance on each subsequent test.
bascally you used 3 differentials to build the variable speed transmission but you used a fixed shaft for the back wheels of the car? Look at the effort the motor is doing when you steer right or left!
i mean i dont see a point of a cvt in a small rc car if it aint gonna go fast if ur going slow theres way way bigger chance ur gonna slip wheels before u have too little torque that main big use i would see this be used in is lpe´s and geared for speed aka realy good acel and realy good torque
Bro I love the concept and ı like ur videos too but if ı were start a channel about legos I used to wear gloves to be different from others. İts just my opinion it could look pro.
That's not a cvt. It's more of a torque converter, or a slipping clutch, but with a belt. Continuously variable transmissions have pulleys that actually move to change the width, thus simulating a larger/smaller pulley relative to the belt
That may be the CVT we're all most familiar with in cars as it's more practical at that scale, and we're not limited to available lego parts. But this is a perfectly valid CVT. It transmits torque and power, and the gear ratio is variable.
Thanks for the comment. I called it a CVT because it can operate through a continuous range of gear ratios, even though it uses a different design to a traditional CVT. I don't think it's the same as a slipping clutch, because the slipping of a clutch will increase the gear ratio but not increase output torque.
It's true that there are some losses due to the slipping belts, so the design still has room for improvement, but I thought it was an interesting and novel concept to make a video on.
There's a volume button on most devices and also volume sliders. It's at more or less the same volume as everything else. Maybe you're just listening at an excessive volume.
Typically, CVTs are used because they're more fuel efficient, not that that's a concern with an RC car! Essentially, it'll give you the right amount of torque for the situation you're in.
@@BananaGearStudios but you didn't build a CVT. The output torque does not increase, you just intorduced slipping rubber bands, which actually WASTES power. This is an incredibly inefficient device, that simply allows for lower output speeds.
I had to squeeze the output as hard as I could to get the gearbox to change into its lowest gear, so I think it would be near impossible to stop it completely. But if you could give it enough resistive torque I assume the motor would just stall.
@@BananaGearStudios near impossible to stop the output rotating? hahahaha how damn weak are you? just grab the spinning red thing - motor would not stall because you added loads of slipping rubber bands remember... :D
So basically without the ratchet the torque just increases infinitely? Also i think your channel is underrated, with how good videos you make, you are defiantly a star in my opinion! Keep up the great work! You've earned a new subscriber!
Um, this isn't how a CVT functions, and slip isnt the goal. The intent of a CVT is to ensure the most efficient engine speed for the velocity of the car. Were you proving a different concept? Because it's a great video but it doesn't demonstrate a CVT transmission with hydraulics, cones and belts. Would love to see you do that with Lego though!
It's a different design to a traditional CVT using cones and belts, but it functions the same way, as seen by the graphs I plotted. The slipping belts are being used as "resistance sensors" to cause the change in gear ratio - they're not functioning as clutches.
@@BananaGearStudios Hey, thanks for answering and clarifying what you were doing there! Really appreciated because my stupid brain couldn't comprehend it on its own. Now I see what you were doing, that's fascinating. Cheers!
@Orion40000 he's still incorrect the proper cvt and how it is continually variable is visible here: th-cam.com/video/PoovYqhYml4/w-d-xo.htmlsi=S4K0PjIZfrUS-DdF
Thanks for the feedback. This was the first video where I tried out having the Lego "build itself". I was happy with how it turned out, but I can understand how hundreds of loud clicking sounds can get pretty annoying lol. I'll try to make it smoother in my future videos.
this is definitely not a cvt..... Its just a mechanical automatic transmission with a torque converter..... You know, what there is in every automatic car ever
Very nice, but next time in the video please add just some non copyright music to keep us entertained in those areas with no sound! It will drastically improve the quality👌
Thanks for the feedback! I was trying to go for more of a relaxing tone for the video, but I'm open to adding some background music if I think it suits a certain section of a video.
I really really like the idea but i wouldn't call it continuously variable transmission. I would call it "Auto slipping trasmission". The CVT is completely different. Anyway about the video it is a bit slow. You should take less time in the video with the building. If you want to make the effect of lego autobuilding, make it faster
40+ yr collection of lego technic up for grabs. i realised the other day... all you do is spend hours finding bits, trying to make something, realising it wont work, so more hours finding more bits to make another variation, to find thats not working, so its more hours searching for more bits... i love lego. i feckin hate lego. i think im just going to throw it in the bin.... buy buy silly little pneumatic cylinders, buy buy flashing blue lights from 1984...
Sometimes it does feel that way... Even in the past few months since I've started this channel, I've had to scrap several designs because they didn't work out. In fact, the original design for this video worked more like a sequential gearbox, but if the load torque was too high it struggled to shift gear, so I had to leave it. I'd say keep at it, but try to learn from your mistakes. Another thing I've found helps is to build a very rough version of your idea to see if it works before trying to make it as sturdy or compact as possible.
@@BananaGearStudios lol. a big challenge is... not having enough? or no order... i know i got one... ONE... somewhere. maybe. but i need two! and sometimes you find a different piece and go back to the first plan. what you achieve blows me away...
Yeah, a few other people have mentioned it as well. This was the first video that I tried having the Lego "build itself", and I'm going to improve on it in my future videos.
How is this a continuously variable transmission? Perhaps the author of this video can study up what a CVT means and does. A CVT has to have continuous range of gear ratios that can be seamlessly changed throughout by the user. This one is anything but a CVT.
This is incorrect, it's not variable, it's just multiple limited slip differentials, which limit the max torque output, and is managed by slip belts and gear ratios. This is mechanically speaking nowhere near a variable transmission. Please learn how those work before you continue to lie to people.
Thanks for the comment, but the gear ratio can vary continuously within a given range, as shown by the graphs I plotted. To my knowledge, that is the definition of a CVT.
@@BananaGearStudiosit feels more like a 4 speed gearbox with a clutches between gears that can blend them, not a true CVT. I would be interested in an efficiency test, I suspect the loss through the belts is very high.
@@danielvanced5526 it in fact would be high losses through the system due to slippage, because a basic automatic transmission has the hydraulic coupling to the power source (electric motor, ICE, windmill, water wheel, etc) via the turbine & pump, or a physical connection with a wearable clutch to a flywheel. Then inside the transmission for an automatic is the gears with set clutches to go full lock to prevent slippage. A manual gearbox has none of that as it is direct gear engagement using the main clutch to the flywheel as the only slipping point. A CVT is a ribbed belt with steel and kevlar integrated into it, it does use a torque converter (hydraulic coupler) or a physical clutch (like a standard trans) to drive it, and is always engaged with the slippage being in the clutch or torque converter, only with the belt moving up and down 2 cones for a continually variable drive input to output ratio, hence the name of it being CVT. What we are witnessing is a continually slipping clutch system between gears.
Haha! You know there would have been the perfect amount of space for one on the rear axle, and it wouldn't even have changed the gear ratio. Part of the reason I chose not to use one was that if one of the wheels came off the ground during the bumpy terrain bit, it would stop the car.
THIS IS NOT A CVT. Your explanation of an automatic transmission at the beginning is complete nonsense - the band slipping in your lego contraption doesn't increase the output torque. Output torque is higher because the motor output is higher (if you measured the current drawn by the motor it will increase when you added resistance) - you can hear the difference in the noise it makes! What you've built here is a torque converter, which simply allows a difference in rotational speed, NOT an increased torque. Power is lost in the slippage to heat, in your case making that little rubber band hot. You are not achieveing higher torque by allowing rubber bands to slip - you are simply allowing the motor to operate at a higher speed than it otherwise would. A CVT on the other hand actually changes the GEAR ratio, achieving a multipler effect on the torque output.
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One thing I'd like to see would be the same car chassis trying to navigate the same obstacles, but with a basic transmission, just to get a frame of reference for how the continuously variable transmission is actually solving a problem that the basic transmission would simply fail at.
Yeah, that's a great idea. It could've been cool to show a side-by-side of the two cars going over terrain or pushing objects. If I make a similar video in the future I'll try to include something like that.
I’m not sure this is a CVT, looks like an automatic transmission to me.
In theory, if the design for a CVT is very low friction, it would be by definition more efficient.
When hybrid vehicles came out they decided the small increase in efficiency was worth the significant increase in cost.
im curious about this as well. ive seen a lot of cvts like this on youtube and for my feeling the extra torque generated by this is wasted on fritction, and in the end you could better hook up to engine one to one to the wheels for the same result. i would love to be proven wrong about this!
@jsbrads1 you are correct it is not a CVT. This is limited torque slip differentials being daisychained together
@@Skulljeep00 not sure how much time it would take to explain every working part, I would be interested in that 😂
I’d say this is more similar to a torque converter and not a cvt transmission. A cvt will basically change the gearing by changing the size of the pulleys that the belt connects to. A torque converter will slip and different amounts to create more or less torque. I hear that the motor was struggling under load. A cvt is nearly 100% efficient so if it was a cvt it would not struggle like that. Instead the pitch of the motor would stay the same and would just lift the load slower
Glad to see at least 1 person who knows the difference...
@@GamezGuru1 yeah it’s easy to tell because a real CVT will never slip or at least should not.
This isn't an actual CVT, the ratios between the two pulleys aren't actually changing. Yes, the second pulley is moving slower, but that's just because the belt is slipping. Any gain in transmitted torque can be explained by a combination of the extra tension pulling the rubber band into the secondary pulley plus localized heating of the rubber band at the point of contact generating more grip, plus the momentum of the primary side dragging it a little harder in pulses.
That's not the case.
The basic principle is the fact that a differential is changing the torque one side when the other side is held tight.
Love the idea, I would instead reverse the transmission to make your creation go faster! Torque is a good way to show how it works, but if you can make a lego car that can go from snail to rocket that would be awesome!
Thanks for the suggestion, but the transmission has to go this way so the output torque increases when the car encounters some resistance. To make it to go faster, I could just increase the gear ratio to the drive shaft, but I chose this speed so it would have enough torque to climb the slope and push the book.
@@BananaGearStudios i mean, thats the point of the transmission. starts slow gets fast and if it encounter something, it goes back to slow. kinda...
@@matthexkt8409 look it kinda does the same the non load speed would be top speed and the lowest speed would be first gear. when a car wants to go it has to overcome friction so it needs more torque at first but then the load slowly decreases so in a normal car you can go to a higher gear and this will also do that because it needs less torque so it speeds up the only difference is that with a car its not based on torque but on engine rpm
@@cuberznl yes. but now the top speed is limited on engine rpm not torque. or power.
@@cuberznl well, you always can do such high rpm and low torque on input shaft, that car cannot start movement before it lower the gear in CVT. The you'll get what you want: slow start, gradual acceleration, high speed with no obstacles.
The only thing this channel needs is more cool content.
Thank you so much! More videos are already in the works!
This is a great representation of how to do science correctly, that it is quantitative and the results from data is how we end up in a conclusion. Great job!
Thank you! I tried to structure that part a bit like a lab report - results, discussion, conclusion.
@@BananaGearStudios except the conclusion is completely wrong! the torque output is not increased by introducing slipping rubber bands. Do the experiment without the bands and you'll see...
I can't believe how far we've come in the world of lego CVTs. It was only a few years ago that a small scale prototype was almost impossible, now we've got this.
this is not a CVT though, it's a torque converter.
Really cool project, great video format. Hope to see more!
Thank you, more is on the way!
this channel Is alot better than people think
This is true...
Thank you!
A real cvt though uses a cone shaped pulley that moves and a v- belt. You change the distance between the cones to increase or decrease the size/ ratio.
Hub van Doorne would have loved to see this, my Volvo has a continuously variable transmission.
Keep up the good work, this might become a (LEGO) technically very interesting channel!
Thank you!
I have an old Daf 66YA with CVT, a Mercedes A class with CVT, and my mum has a Nissan with CVT. That's probably why I was hoping this would be a video about an actual CVT, not about something that kind of produces the same result as a CVT.
@@GuusJanssen indeed, it is absolutely NOT a CVT. The CVT in your car actually DOES increase output torque by reducing the gear ratio. This LEGO device simply introduces slippage.
Very good content ❤
Wish you all the best and keep it up 👍🏻
It must be a strange feeling when you push against the vehicle and you feel it respond by pushing harder against you
This is a torque converter if anything, but not a cvt
The first design is fairly similar to how Toyota hybrid CVTs work, but those have an electric motor instead of a band to adjust the gear ratio.
This works in a similar manner to an automatic gearbox I made and has the same modular capabilities, very cool!
This video is great, thank you!
It’d be great to see this car and another car compete at a sled pull or similar heavy object pushing contest
Brilliant! Thanks for sharing.
So what do the red gears do? I now have a basic understanding of how this transmission works, but first showing of their function would make it more clear.
I still don't understand the whole concept. Maybe if you read this you would be nice enough to explain how the gear ratio expands just by the rubber band slipping 🤔🥲I can't understand it
This is a excellent and high-tech idea joh-eun !
우수하고 첨단기술이 좋은 아이디어
You just earned a new sub
Why did you underdrive the pulleys, relative to the other input to the differentials? If you had made the pulleys spin at the same speed as the other input (or faster), then you would have had a wider gear range, per stage. Would that have been too much torque on the system? Or melt the bands?
Brillant, variable transmission: from slow gear to super slow gear.
idea for another video
combine all such conveniences into one super off-road car for remote control
if you make an automatic gear box + this and a few others, it could be interesting
That sounds awesome, I like the idea! I've already got several more videos in the works, but I'll keep this idea in mind once I've finished them.
Just one more differential on the rear axis and the car is perfect.
The differential gear ratio in your car at home is likely to be somewhere around 2.42 or 2.73. Your automatic transmission multiplies this by using various gear ratios around 3.06 - 0.7.
For larger engines maybe. A lot of fwd cars are utilizing things more like a 4.11:1 or in some cases I'm aware of, a factory 4 cylinder car with a manual trans and a final drive ratio from factory of 4.56:1 an this is not uncommon. Gear ratios like the ones you listed are more commonly found in pickups, especially with the more common use of high gear count automatics with multiple gears actually being an overdrive ratio like you listed. The ratios transmissions tend to use seems to be a pretty accurate range.
@@goosenotmaverick1156 Additional info is appreciated. As you suggested, I'm used to 5.7L V8s. Specifically Chevrolet.
Addendum: I do not own a pickup truck.
@@frikyouall I knew where you were coming from. I grew up a die hard GM kid and got into Hondas and have learned everything in between and beyond that I can get my hands on. I see a lot of different stuff from kei trucks, motorcycles, to 2.5 ton trucks and tractors. You were pretty spot on with the other ratios. Props on that.
Why familiar with the GM (likely vortec or the older TBI setups? Maybe TPI motors) but not having a pickup? That's where I find most of the 5.7L familiar folks. Killer engines, killed by stringent emissions requirements.
@@goosenotmaverick1156 I never really liked pickups. Prefer to be on the ground with a better center of gravity. Just personal preference.
I have '75 El Camino (truck, but not a pickup) that I swapped a '79 RV motor into out of necessity, and a '94 Roadmaster that probably needs a new Opti. So an A-body and a B-body.
Looked into putting a 700R4 into the Camino a few times, but settled on the stock TH350 for towing, and am considering a 3.42 or higher posi for the rear. Basically, I spend a lot of time playing with gear ratios. Not as much as the Lego guy, but still a lot, I should think.
I started with a Honda, but it wasn't until I got an AMC that I cared enough to learn anything. When everything needs to be replaced or rebuilt, you tend to start paying attention. So you have my respect for learning while you had the opportunity, and not out of necessity.
this paractice gear system is incredible
Thank you!
Cool Video Keep making them!
Thank you!
Sur la dernière présentation, est ce que l'on peut remplacer les roues par un système de chenille ?
Interesting solution to a Lego CVT, nice!
Just discovered your channel, and as one who also likes legos and gears and mechanical things, youve earned a new subscriber! A new gear to your machine :) ⚙️
Thank you! Welcome to the channel :)
@@BananaGearStudios Happy to be here! I look forward to seeing more of your creations
Interesting concept. Personally, I think having a much greater gear ratio difference within each stage of the transmission might be a good thing, but I don't really know if that would work with the current design. Additionally, I think the highest gear ratio seemed a little high. In the basically no-load scenario, the transmission has a ratio of 6.06:1 which is quite deep. A typical car transmission has a first gear ratio around 3.6:1 or so, and the highest gear ratio is either ~1:1 or even an overdrive, 0.8:1 or so. However, if we took the base ratio of your gearbox to be a 1:1, then the maximum gearing is actually only 2.2:1 or so, which is roughly second gear for a car. What I suppose I'm saying is that I think the transmission would be more realistic if it actually had a larger range of speeds. Using the percentage measurements you gave, a normal car transmission would have a range of about 350% or greater.
I suppose this is coming across somewhat negative. On the contrary, I think it's a very interesting design and not something I'd have been able to come up with. I guess I was just hoping to see something more like a truck transmission, and a test being it having to accelerate a heavy vehicle up to speed.
Oh, and one other note. Some of the scenes in the video are a little slow, and I think some background music would really help. You could try it out and see if it boosts viewer retention. And I just realized you're a super small channel. Honestly I thought you were a relatively big channel with a couple thousand or tens of thousands of subscribers. Keep up the good work, and I think your channel will grow pretty fast.
Thanks for your comment, lots to think about! Regarding the gear ratio range, I remember testing out a few variations of the design, and it worked best with each stage of the transmission having this gear ratio range, so the only way to increase the range would have been to add more stages. I actually considered that, but thought that three was enough to showcase the principle of the design without it being too complex. Getting it to accelerate a heavy vehicle is a great idea though.
About the background music, I quite like the style of just listening to the sounds of the pieces and the motors, but I'm open to adding some background music if I think it suits the video.
You forgot to factor in final drive ratios when you were comparing to ratios in cars. Ranging anywhere from the high side of 2:1 all the way upwards of 5:1 or a bit higher depending on the application. And that's applied after the ratios within the transmission are applied. So a 3:1 ratio, PLUS the ratio of the final drive let's just call it 4:1....
I would like to see those red grey cogs from close to see how they work
Omg it’s unstoppable! 😂 Good job.
Haha! Thanks!
is it really continously variable though? i mean it still has fixed individual gears and you can also see that on the torque graph very clearly
From where I can buy these lego kits?
I wonder if you could use a worm gear instead of a ratchet to create a sort of one way "torque valve", while still allowing the motor to turn the diff in reverse. Also you should use a clutch gear instead of slipping a rubber band.
Have you tried buwizz yet? I feel like that could change how much power these have drastically and improve your builds with much less effort.
Not yet, but I'm sure I'll try them out in the future.
Neat idea but I doubt the pulley will survive long
??? You can do the same thing in a car by slipping the clutch. You can alter input/output 'gear ratio' all you want, but there are huge friction losses until the slipping stops.
Thanks for the comment. As far as I understand, a slipping clutch will increase the gear ratio, but not increase output torque, whereas this design uses the slipping belts to alter the gear ratio through the differentials, resulting in higher output torque.
Google "elastic slip"
@@BananaGearStudios There is NO variation of gear ratio in your setup whatsoever! All there is, is slip slowing down and weakening the output and wasting power by converting it into friction and heat instead of driving the output shaft.
@@BananaGearStudios what do you think the differentials are doing exactly, magic?
I wonder how it compares to just a single gear reduction of the same unloaded ratio? As it would be a nice way to see how much efficiency is lost through the slipping, as I'm sure there are some losses associated with that.
Would be interesting to see times it took to lift the weight so we could calculate the power and from that the power loss...
people seem to have no idea what a CVT is about. Ofcourse you an change the speed of the output of a differential if you put a variable brake system on the other side. Bit that is far from beeing a CVT.
when the pulley slips it does not change the ratio.
Does that mean you can never have not enough touque
Couldn’t you do this in a car, by utilizing a torque converter as the “slipping pulley” part of the system? This would overcome the CVT’s main problem in modern vehicles, that they aren’t that good for high torque applications.
You could and if you did then you would only be wasting fuel and reducing the torque output of your motor compared to a conventional transmission, just like this useless Lego setup does. Compared to a conventional gearbox with the same gear ratio this setup effectively only makes the motor WEAKER, not stronger!
@@tomwoggle9411 correct, finally somebody who understands the difference between a CVT, and slipping rubber bands!
@@tomwoggle9411 this doesn’t answer my question. I’m asking about improving the current CVTs that already exist in the car market today. I know CVTs aren’t as efficient as a traditional geared tradition. Care to actually answer my question.
@@ATTACKofthe6STRINGS I did answer your question.
All a slipping pulley 'achieves' is massive wear and friction loss. It's practically just like driving around with a constantly slipping clutch.
Neither a slipping belt, nor a slipping clutch increase torque output in any way or form, in fact they REDUCE torque output and waste fuel by generating heat instead of propulsion.
Aside from imperfections a CVT alters the gear ration and does NOT slip. It commonly just has slightly higher losses than gears do, but it doesn't nearly generate as huge losses as a slipping clutch or slipping belt drive do.
I'm sorry to bring it to you and to bust your bubble, but your 'brilliant' suggestion of doing this slipping belt drive in a real car is really just stupid and that is why no car manufacturer does it.
It's not like belt drives and clutches (slipping or not) haven't been around for well over two centuries by now.
If a slipping belt drive somehow magically really changed the gear ratio and did what you think it does, wouldn't you expect it to be a standard application ever since steam engines were used with belt drives in the 18th century?
@@ATTACKofthe6STRINGS In fact I did answer your question. You obviously just didn't fully understand what I commented or you weren't able to fully comprehend the consequences of my explanation on the complete and utter uselessness of your suggestion.
A slipping belt drive, just like a slipping clutch does NOT increase torque output of an engine.
It also does NOT change gear the ratio which a CVT transmission does!
CVT transmissions aren't designed to have a lot of slip (some CVT designs, especially those based on torque converters do have minor slip, but only by a few % which isn't nearly as much as a slipping belt drive shows)
All a slipping belt drive really 'achieves', is to REDUCE torque output and waste fuel by generating massive wear and lots of heat via friction. The only way this slipping belt drive can actually be useful is by either functioning as a kind of clutch or by functioning as a torque limiter, so more or less as a safety feature.
If your 'brilliant' suggestion of using a slipping belt drive instead of a CVT would actually work and had any benefits, then it would have long been a standard application in vehicles and machines.
It's not like belt drives (and the problems around slipping belt drives) haven't already been around for long over 2 centuries by now.
Yep my lawnmower transmission works exactly that way.
How can the output rotations vary this much when its the identical trave distance for the weight? is the string stretching?
Great question! Looking at the results tables, the number of output rotations stays fairly constant for each weight, corresponding to the fact that the weight moves roughly the same distance, as you said. However, the number of input rotations increases across the tests, resulting in the gear ratio increasing. You can see the changing gear ratio because the weight takes longer to be lifted the same distance on each subsequent test.
@@BananaGearStudios i got that, i was just surprised by the differences of the output rotation
@dazley8021 Fair enough, I suppose from the camera angle it's a bit hard to judge exactly how far the weight's moved.
bascally you used 3 differentials to build the variable speed transmission but you used a fixed shaft for the back wheels of the car? Look at the effort the motor is doing when you steer right or left!
Maybe that’s technically a cvt transmission but it’s not really how they work in vehicles
i mean i dont see a point of a cvt in a small rc car if it aint gonna go fast if ur going slow theres way way bigger chance ur gonna slip wheels before u have too little torque
that main big use i would see this be used in is lpe´s and geared for speed aka realy good acel and realy good torque
Bro I love the concept and ı like ur videos too but if ı were start a channel about legos I used to wear gloves to be different from others. İts just my opinion it could look pro.
That's not a cvt. It's more of a torque converter, or a slipping clutch, but with a belt. Continuously variable transmissions have pulleys that actually move to change the width, thus simulating a larger/smaller pulley relative to the belt
This is exactly what I was thinking. If anything it looks like the motor is bogging down with the load.
That may be the CVT we're all most familiar with in cars as it's more practical at that scale, and we're not limited to available lego parts. But this is a perfectly valid CVT. It transmits torque and power, and the gear ratio is variable.
Even if you could call this a cvt, I don’t really get why you would need this in a vehicle. Looks pretty inefficient with all those slipping belts
Thanks for the comment. I called it a CVT because it can operate through a continuous range of gear ratios, even though it uses a different design to a traditional CVT. I don't think it's the same as a slipping clutch, because the slipping of a clutch will increase the gear ratio but not increase output torque.
It's true that there are some losses due to the slipping belts, so the design still has room for improvement, but I thought it was an interesting and novel concept to make a video on.
Could you please turn down the ticking sound during building? It is VERY loud and annoying ;). Apart from that: great video, great idea!
There's a volume button on most devices and also volume sliders. It's at more or less the same volume as everything else. Maybe you're just listening at an excessive volume.
Agreed. It's just a canned repeated recording of the same click too. Trying to do ASMR, but failing.
12:21 HEADPHONE WARNING!!!!!
I don't get the gear system... but I love it!!!
Thanks!
The sounds of building are awful but the idea presentation is brilliant
You got a new subscriber)
Thanks for the feedback! This was the first video where I incorporated the pieces "building themselves", and I'll improve it in my future videos.
@@BananaGearStudios Looking forward to the new educational videos!
What use does this have in real life if you don’t mind me asking?
Typically, CVTs are used because they're more fuel efficient, not that that's a concern with an RC car! Essentially, it'll give you the right amount of torque for the situation you're in.
@@BananaGearStudios but you didn't build a CVT. The output torque does not increase, you just intorduced slipping rubber bands, which actually WASTES power. This is an incredibly inefficient device, that simply allows for lower output speeds.
Out of curiosity where do you get all your parts ?
I get mine from sellers on Bricklink
Next make a torsen diff!
if this design was in a car. you would have to change belts ever 10 miles :(
incase this channel gets famous, i was your 382nd subscriber
Haha! I appreciate it!
It appears to be famous now, I got it in my algorithm and the channel has over 1k subs
This is too complicated for my baby brain to handle.
damn thats hella cool
Thanks!
@@BananaGearStudios would love to try out a design like that, what happens if the output stalls?
I had to squeeze the output as hard as I could to get the gearbox to change into its lowest gear, so I think it would be near impossible to stop it completely. But if you could give it enough resistive torque I assume the motor would just stall.
@@BananaGearStudios ooh ight ty
@@BananaGearStudios near impossible to stop the output rotating? hahahaha how damn weak are you? just grab the spinning red thing - motor would not stall because you added loads of slipping rubber bands remember... :D
I had 10 ADS POP UP BEFORE I WATCHED THE VIDEO HOWWW?
So basically without the ratchet the torque just increases infinitely? Also i think your channel is underrated, with how good videos you make, you are defiantly a star in my opinion! Keep up the great work! You've earned a new subscriber!
Nissan making they cvts like
Um, this isn't how a CVT functions, and slip isnt the goal. The intent of a CVT is to ensure the most efficient engine speed for the velocity of the car. Were you proving a different concept? Because it's a great video but it doesn't demonstrate a CVT transmission with hydraulics, cones and belts.
Would love to see you do that with Lego though!
It's a different design to a traditional CVT using cones and belts, but it functions the same way, as seen by the graphs I plotted. The slipping belts are being used as "resistance sensors" to cause the change in gear ratio - they're not functioning as clutches.
@@BananaGearStudios Hey, thanks for answering and clarifying what you were doing there! Really appreciated because my stupid brain couldn't comprehend it on its own. Now I see what you were doing, that's fascinating. Cheers!
@Orion40000 he's still incorrect the proper cvt and how it is continually variable is visible here:
th-cam.com/video/PoovYqhYml4/w-d-xo.htmlsi=S4K0PjIZfrUS-DdF
@@Orion40000 why are you listening to somebody who plays with LEGO - this device does NOT increase output torque.
good video but those lego connecting sounds are too loud and often they get annoying
Thanks for the feedback. This was the first video where I tried out having the Lego "build itself". I was happy with how it turned out, but I can understand how hundreds of loud clicking sounds can get pretty annoying lol. I'll try to make it smoother in my future videos.
@@BananaGearStudios for me that was the worst part, would prefer a time laps or anything else good video though
Thanks, I'll bear that in mind.
Hear me out make it tiled so you can put another cvt and attach it then it’s infinite cvt
Better than Nissan's. :P
this is definitely not a cvt..... Its just a mechanical automatic transmission with a torque converter..... You know, what there is in every automatic car ever
True tho
Very nice, but next time in the video please add just some non copyright music to keep us entertained in those areas with no sound! It will drastically improve the quality👌
Thanks for the feedback! I was trying to go for more of a relaxing tone for the video, but I'm open to adding some background music if I think it suits a certain section of a video.
I don't get it but I like it a lot!
Haha! Thanks :)
I really really like the idea but i wouldn't call it continuously variable transmission. I would call it "Auto slipping trasmission". The CVT is completely different.
Anyway about the video it is a bit slow. You should take less time in the video with the building. If you want to make the effect of lego autobuilding, make it faster
I was thinking the same thing. This is just two equally sized pulleys slipping with no way to change the ratio like a normal CVT.
40+ yr collection of lego technic up for grabs.
i realised the other day... all you do is spend hours finding bits, trying to make something, realising it wont work, so more hours finding more bits to make another variation, to find thats not working, so its more hours searching for more bits...
i love lego. i feckin hate lego.
i think im just going to throw it in the bin.... buy buy silly little pneumatic cylinders, buy buy flashing blue lights from 1984...
Sometimes it does feel that way... Even in the past few months since I've started this channel, I've had to scrap several designs because they didn't work out. In fact, the original design for this video worked more like a sequential gearbox, but if the load torque was too high it struggled to shift gear, so I had to leave it. I'd say keep at it, but try to learn from your mistakes. Another thing I've found helps is to build a very rough version of your idea to see if it works before trying to make it as sturdy or compact as possible.
@@BananaGearStudios lol. a big challenge is... not having enough? or no order...
i know i got one... ONE... somewhere. maybe.
but i need two!
and sometimes you find a different piece and go back to the first plan.
what you achieve blows me away...
@@paradiselost9946 please don’t bin it, donate it to me! I’ll build something amazing, I have lots of useful ideas, just not enough Technic pieces.
This ain't a CVT
the clicks when building are one hell of an earache, otherwise cool content
Yeah, a few other people have mentioned it as well. This was the first video that I tried having the Lego "build itself", and I'm going to improve on it in my future videos.
How is this a continuously variable transmission? Perhaps the author of this video can study up what a CVT means and does. A CVT has to have continuous range of gear ratios that can be seamlessly changed throughout by the user. This one is anything but a CVT.
This is incorrect, it's not variable, it's just multiple limited slip differentials, which limit the max torque output, and is managed by slip belts and gear ratios.
This is mechanically speaking nowhere near a variable transmission. Please learn how those work before you continue to lie to people.
Thanks for the comment, but the gear ratio can vary continuously within a given range, as shown by the graphs I plotted. To my knowledge, that is the definition of a CVT.
@@BananaGearStudios this is a true CVT if you want to know the mechanics of it.
th-cam.com/video/PoovYqhYml4/w-d-xo.htmlsi=S4K0PjIZfrUS-DdF
@@BananaGearStudiosit feels more like a 4 speed gearbox with a clutches between gears that can blend them, not a true CVT. I would be interested in an efficiency test, I suspect the loss through the belts is very high.
@@danielvanced5526 it in fact would be high losses through the system due to slippage, because a basic automatic transmission has the hydraulic coupling to the power source (electric motor, ICE, windmill, water wheel, etc) via the turbine & pump, or a physical connection with a wearable clutch to a flywheel. Then inside the transmission for an automatic is the gears with set clutches to go full lock to prevent slippage. A manual gearbox has none of that as it is direct gear engagement using the main clutch to the flywheel as the only slipping point.
A CVT is a ribbed belt with steel and kevlar integrated into it, it does use a torque converter (hydraulic coupler) or a physical clutch (like a standard trans) to drive it, and is always engaged with the slippage being in the clutch or torque converter, only with the belt moving up and down 2 cones for a continually variable drive input to output ratio, hence the name of it being CVT.
What we are witnessing is a continually slipping clutch system between gears.
Imagine having all those differentials and not putting one between the wheels on the rear axle. 🙄
Haha! You know there would have been the perfect amount of space for one on the rear axle, and it wouldn't even have changed the gear ratio. Part of the reason I chose not to use one was that if one of the wheels came off the ground during the bumpy terrain bit, it would stop the car.
Probably breaks less then Nissan’s
Haha!
not really a cvt per say but is cool none the less
Too slow, try using two or more electric motors for thrust
I felt that just the one motor was enough to showcase it working, but yes, I could have made it faster by using more motors.
THIS IS NOT A CVT.
Your explanation of an automatic transmission at the beginning is complete nonsense - the band slipping in your lego contraption doesn't increase the output torque. Output torque is higher because the motor output is higher (if you measured the current drawn by the motor it will increase when you added resistance) - you can hear the difference in the noise it makes!
What you've built here is a torque converter, which simply allows a difference in rotational speed, NOT an increased torque. Power is lost in the slippage to heat, in your case making that little rubber band hot. You are not achieveing higher torque by allowing rubber bands to slip - you are simply allowing the motor to operate at a higher speed than it otherwise would. A CVT on the other hand actually changes the GEAR ratio, achieving a multipler effect on the torque output.
Desmocedici rachet...
i do like watching lego videos on cars but the clicking sounds make me not want to watch this video, its annoying
しょうもな。
the fake lego click noises aren't doing it for me, gotta be honest
Repetitives tiks 🤯👎