How do automatic transmissions work?
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- เผยแพร่เมื่อ 16 พ.ค. 2024
- Automatic transmissions are one of the least understood mechanisms, but they are some of the most widely used IN THE UNITED STATES. Almost all cars on the road IN THE UNITED STATES have an automatic transmission. In this video I will use my 3d printed model of an automatic transmission to show you (generally) how they work.
Learn more here:
Based off a Simpson Planetary Gear Set: en.wikipedia.org/wiki/Simpson...
Download my 3d printable automatic transmission model:
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This model is based off a Simpson planetary gear set. "A Simpson gearset delivers three forward gears and one reverse, plus neutral, and is commonly employed in three and four velocity automatic transmissions." You can read more about it here: en.wikipedia.org/wiki/Simpson_planetary_gearset
Edit / Video Correction: *In the US, 96% of cars on the road are automatic, manual transmissions are more common in the rest of the world. Manual transmissions are more widely used because "they are more reliable; cost less to operate; have more power; are stronger, and make your car more economic".
This is how a planetary gearset works, not necessarily how an automatic transmission works. The main thing that makes "automatic" transmissions to be automatic are the gearshift actuators and sensors. Even dual-clutch transmissions can have an "automatic" mode, making them automatic without using planetary gearsets.
@@sepg5084 That's about the most idiotically pedantic comment in the history of comments sections. Almost every single automatic transmission used in any car in the world uses planetary gears.
The proper name is planet carrier gears.
Good attempt, but falls off into total confusion after about the 3rd sentence.
Those 2 handle gears sticking out the back throw everything off.
Maybe making those ring gears out of transparent or "hatched" plastic would help.
I've never seen an attempted description of an automatic transmission that didn't make me hate the subject.
Almost all car on the road in the US are automatic. In Europe it is the other way around.
Yes we have even jokes about it. Fo you want to have thief proof car in USA? Just have manual...
I probably couldn't drive a manual if I tried. Timing the shifts would probably be too much for me.
@@thatblackkid22 Trust me it's just about training nothing else almost anyone can learn it
@@thatblackkid22 what do you mean timing? If the engine goes brrrr you shift up and when it sounds like it is dying you shift down. Its not that hard.
@@marekvojta9648 if you want to go even further, get a three on the tree manual. On the other hand they might blow up your engine wondering why the heck isn't this thing shifting, that is if they even knew to step on the clutch to be able to get it into gear without just grinding in the first place.
Exactly every tutorial on TH-cam showing how “automatic transmission works “ just showing how the planetary gears rotate. No explanation how why and what’s the “automatic “ thing there.
No doubt, great job with 3D printing!
you need to search for torque converter for the other part
@@farerse I've done this many times, still doesn't explain the automation of the gear shifts
@@meemdoggoriginallongdrinkthat's the job of the valve body.. a speed sensor inside the transmission reads the input speed , depending on the speed some passages are opened or closed in the valve body . they are usually opened or closed with solenoids
@@farerseI thought the thing that makes "decisions" in terms of gear shifts and controls the transmission has been electronic in all cars made since the 80s or 90s.
@@roymarshall_I'm not a specialist but I think you are correct, the speed sensor generates voltage which the tcu use to calculate what gear to use, and activate or deactivate electronic solenoids inside the valve body. I don't know how it was done before this.
While watching, I felt like I understood everything. And then the video ended and I still have no idea how an automatic transmission works
me too. seems not automatic if he uses hands to hold the gears
Yeah, it's super easy. So, once you shift into drive, you then press the accelerator. As you speed up, you will need to change gears so, all you do is cut a hole in your car's floorboards and transmission housing. Then, anytime you need to change gears, you just reach down and grab the small blue gear, followed by the small red gear. Finally, you let go of the gears, pull back your bloody stump that was formerly your hand and now you can ride comfortably along in third gear.
Me too. What is the mechanism that selects the gear?
@@1969EType wow Bro... You made is so easy to understand... Thankssss ❤
@@yashnirhalimusic No charge, bruh…happy to make your day and ahhhhhh…don’t hurt yourself.
That's how the planetary gear set works. but the units themselves are essentially hydraulically driven. you now have to get into the operation of that system with the fluid pump, the valve body and torque converter. the latter being one of the most misunderstood components, not so much the gear box.
yeah, here he isnt really even showing an automatic transmission, just a linked planetary gearset with different ratios
@@addmix Indeed. If I remember correctly, the Ford Model T actually used planetary gears but with a manual shifter.
@@addmixhe needs to hook it up to a computer for it to be ahtomatic
This is the correct answer.
It is vacuum and hydraulic fluid computer.
This explains how the gearing works but not what makes it automatic. How/when are those shifts actually made?
the computer decides when to shift duh
@@rondg2 There is no computer here, and I'm pretty sure real transmissions aren't controlled electronically either. They have intricate hydraulic systems that look kind of like brains that trigger shifting based on pressure, and the pressure changes based on speed and output resistance. Is this mechanism called the "computer"?? In any case, the thing that makes an automatic transmission automatic is the automatic shifting, not the gear arrangement, and this little demonstration is only a gear arrangement.
@@rondg2 Specifically, it's an analog "computer" called the valve body. Over the last couple of decades, they've been migrating to an actually electronic computer bit by bit but they had automatic transmissions for many decades before electronic computers even existed. Here's a video about valve bodies: th-cam.com/video/g1eCAqKjIh8/w-d-xo.htmlsi=LljfBxvxnodlZzPJ
This didn't explain how an automatic transmission works? Just ow planetar gearing works, no? I mean, how does the gerabox determin which gears to use, isn't that the "automatic" part of it, which you didn't explain at all?
Some secrets are not meant to be knowable for mortal minds!
This is more like a planetary gear transmission rather than how an automatic transmission works.
Yes, but no. He even didn't explain how planetary works. Like at all.
this doesn't even look like an automatic transmission, more like manual transmission in american style where you switch up/down in a single line to change gears.
Automatic transmissions typically use planetary gears.
@@nrgzrbunny7775 there usualy hydramatics nowadat
@@D4no00 ATs look like this in good cars with newer transitions or performance cars.
How do I know author lives in USA?
"Almost all car on the road are automatic" 🤣
no one asked
@@morzinbo I personally asked my friend maciej to post the comment.
@@charbelalam2648 and I seconded the ask
@@morzinbo on the contrary, nobody seems to have asked for your comment
@@skjorta1984 let it be known that I asked for morzinbo's comment
I love when people are able to use tools, that people are really getting into, to explain science. Such as this makes it easier for the younger generation to understand this kind of mechanism without needing to go to college for engineering. Younger people already have their 3d printers so this becomes more relatable. Good video.
Nice. I'm still working on mine. Trying to figure out how to simulate the clutch packs. There's 5 of them and 3 planetary sets, as well as two 1-way clutches. I keep getting distracted with side projects. Will finish sometime this year I hope.
Could do a “ratchet” gear that can only handle so much force or speed then it lets go and as it slows down it re ingages like a torque converter
You would need a torque converter as the clutch packs work on hydraulic pressure
you could just make it big enough to fit actual clutch packs, then you need bands as well to show how shifting works
It's almost the end of the year, how is it going along?
Toque converter is also very important part of automatic transmission, as it allows to make your car stay still without turning off your engine.
This explanation is as clear as mud!
exactly
Nice job! Nevertheless what I'm missing here, is how this works automatically - you still manually select which handle to hold.
This type of gearbox was selected for automatics because it is simpler to control. But how the car choose which gear to select? Was it always computer, or were there some clever mechanical ways (in older cars)?
Older Automatics used things like spring loaded valve bodies, as RPM increased so did the pressure from a driven pump in the transmission causing the valves to open which would send pressure to pistons connected to brake bands around the planetary carriers, modern transmissions work almost the same but with solenoids opening the valves to tighten the bands with the ECU having a set shifting strategy in it from factory. This is atleast my understanding of how it works but I may be wrong, it's also important to note that some manufacturers don't use planetary sets in their automatics, the Volkswagen DSG transmission is one such case.
@@HStahlberg Awesome information, there's also CVT which are continously variable, meaning that the gear ratio varies with V-shaped pulleys that can change their diameter, making the output/input ratio smaller or bigger depending on the speed you need.
Exactly what this man says. This is the most important bit and it’s been left out. Not a very good explanation really.
started as hydraulic from what I remember and then eventually moved to computer controlled
Pressure...it's all based on pressure
"Amost all cars on the road are automatic"
Laughs in Germany
*laughs in europe
*Laughs in the world* the only people lazy enough to buy automatic its in the us.
@@santiagoperez2094 what kind words
Efficient* An automatic will always outrun a manual transmission
@@the_expidition427 efficiency isnt about speed. and this kind of transmission neither is more efficient as it wastes a lot of fuel just to operate itself and because of that, it conveys less torque to the drive shaft than the manual.
The majority of cars world wide still use manual transmission. Up to 2018, the majority of cars sold in Germany had manual transmission, only in 2019 the automatic ones overtook them (55% automatic), however, this is for new cars sold, not cars on the road. Actually the reason why manual transmission will soon die out is not because of automatic transmission but because of electric cars. Also the majority of German automatic cars don't use an automatic transmission as shown in that video, actually they use the same transmission that a car with manual transmission does use, it's just operated automatically and has two clutches, which allows for very smooth transmission without any noticeable tractive force interruption while doing so.
Yes so True. It is even more convenient to use manuel in hills/Mountains or drive more economically.
The most important reason for new cars (combustion cars) having automatic are new security and assistance systems build into the cars that make automatic more important and even needed.
And modern Automatic are more efficient so it also shrinks the over all CO2 output from the fleet which becomes more and more important. Not only because of regulations but also because of the customers want it to be more efficient and sustainable
Hahaha EVs killing manuals.
That's not happening unless some serious breakthrough is made in the technology, there is simply not enough lithium on earth for the us alone, let alone the rest of the world.
@@gamechip06 you are wrong m8
@@gamechip06An electric car only contains around 8 kg of Lithium. Currently we harvest 90 million kg of Lithium per year. The earth has approximately 88 million tons of Lithium we could harvest, that's 88000 million kg. For comparison, there are only 1.4 billion cars world wide. Those would require 11200 million kg Lithium in total.
And the first sodium-ion battery, which has the same energy density as a lithium iron phosphate battery in terms of volume, is cheaper to produce and has a longer service life, will be launched on the market this year. Although it is somewhat heavier (lithium batteries deliver 260 Wh/kg, this one will deliver 200 Wh/kg), it will mainly be used in SUVs, where 30% more battery weight will not matter; although the Chinese manufacturer BYD also wants to use them in small cars, simply because they are so inexpensive. As already mentioned, the advantage is also the long service life (they lose capacity much more slowly as they do not age as much) and that sodium batteries are much less sensitive to temperature and also much better for the environment.
Works every time without fail. Just search TH-cam and you can fix your own car in no time! Thanks for the tutorial! Saved me thousands of dollars in repairs!
My Hero!
The most important thing noone else mentioned (that easy) until now ist the shared sungear! That was the one thing I needed to finally understand this simply built mechanism! 🙏🏽
Okay? So how does it automatically change the gears?
In a real car actuators will do the job.
Hydraulically in older cars
Computer controlled on newer ones
@@ahmedyassir5569 Nope. It is a series of hydraulic valves that are interconnected. The valve block looks a lot like a metal maze.
He changed the ratio by stopping the "handle" gears from spinning, in a real automatic transmission a clutch pack clamps down to perform that job
it does it automatically
@@protoborgthat's what the point of the actuators are....
but how does it shift smoothly through the gears
also how does a reverse gear work?
It shifts smoothly due to the torque converter that is between the engine and transmission, and reverse is just using a different ratio in the transmission with the output being in the opposite direction of rotation
Sun is input
Carrier is held so the planets act as an idler
Ring is the output
Boom reverse
You left out the only thing I didn't understand about an automatic gearbox. How the mechanism works that selects the appropriate gear.
Well that's just a planetary gear set which can exist in manual transmissions too but really doesn't explain how automatic transmissions work at all the are hydraulic circuits and steels and frictions and accumulators and all kids of stuff I mean I really have only messed with a 4l60e so I don't know much about others but they are mostly kinda similar
it would be awesome if we could have a model of ravigneaux gearset, which can provide several gear ratios in a compact design.
and which is also quite a popular choice in automatic transmission
This is very interesting. Before I retired I worked in a plastic factory that made components for automatic transmissions. Now I understand what the parts I made did.
So whats stopping the 1st and 2nd gear? How does it stop at certain rpm?
Did you already do a standard?
If not I recommend
This is awesome! ❤Thank you!
It would have been helpful if the orange wheel had had marking s on it so that we could see the rotation
Great explanation of the gear ratios, but how does it change gear automatically?
I assume theres a mechanism that just blocks the red/blue lever gear? Driven by pneumatics or so.
@@termitreter6545 yeah, thats supposed to be the point of the video.which actually lacks of the explanation.
This only explains a planetary gear transmition instead of a automatic transmition
@@magicalchords5145 i've never heard of this type of transmission being described as a planetary gear one; it was always called an automatic because autos always used planetary gears. with the introduction of DCTs now they're called torque converter autos or 'conventional' autos. I made another comment on this thread describing the basic operation of how gears are changed automatically
@@termitreter6545 they're hydraulic or electric, no modern system is pneumatic.
Been here since 110k subs and I love your videos since,
It's worth mentioning that for a reverse rotation output, the planet carrier would have to be the held member of the three. A very good video nonetheless. Now add some other videos of how a torque converter and valve body works to give viewers a complete picture of how an automatic transmission works.
You have to manually switch the gears by holding the blue or red gear. The literal definition of manual. Maybe redo this one and show actual automatic shift based on the RPM.
Very simple but effective explanation. Thank you for the video
I just about get that this shows how the mechanism gives different gear ratios, though not why it uses a planetary arrangement. What I don't get at all (I'm in UK, where most cars are _not_ automatic, but I've owned several automatics) is how it does what its name suggests: _automatically_ "know" when to change, and then does so. (Including, how it works when the car is stationary without stalling the engine.)
perfect demo! thanks so much
Amazing🎉🎉
Thank you ❤️
That was a wonderful explanation. I had no idea how it worked and now I understand the concept a lot more now thanks!
Just be aware that this isn't actually explaining an automatic transmission. It's explaining a planetary gear set. The thing that makes an automatic transmission automatic is a sophisticated hydraulic mechanism, essentially an analog computer, that compares input speed and output resistance (measured as pressure on hydraulic lines) and automagically makes gear shifts (by sending hydraulic fluid back out other lines). Do a Google Image search for "automatic transmission valve body". And, the thing that allows it to shift smoothly is called the "torque converter", which is a fluid clutch. The hydraulic signals to the torque converter momentarily disengage the input to allow gear shifts without grinding the gears. _That_ is the real "how" of how an automatic transmission works.
This video explains what makes an automatic transmission "automatic": th-cam.com/video/g1eCAqKjIh8/w-d-xo.htmlsi=LljfBxvxnodlZzPJ
You did a great job on these models!
Wow I appreciate that.
Great vid 👍👍
Great video! Made it very clear
Excellent and easy to understand. Well done!
This is amazing
I drive an Automatic and have always wondered how the gears work. Now I know, Thanks.
Came to see a demonstration of how gears change automatically in an automatic transmission.
I still haven't seen that. In fact, despite being labeled "automatic transmission" I'm not convinced this isn't a manual transmission
Interesting, haven't seen a 3D printed auto transmission before, it really help to understand
These youtubers pulling out all the stops to make sure we fkn understand the automatic transmission
Almost all cars?🤔
He's american.
USA = whole world
It's amazing how this little plastic gear can move an entire car. Amazing ingenuity
Now THIS is real explanation. That 3d and 2d model ones made it more confusing.
Fantastic! Thank you!
Possible for you to do a CVT gearbox?
This is one of those things that's so sophisticated and so simple in hindsight, sort of like a record player
Thank you for this video
In the US “almost all cars on the road are automatic” there fixed for you
No, he was correct. Worldwide, Automatics are now the norm, with only older vehicles and certain markets being majority manual.
@@dancooper6002no they aren’t. EU has more manuals on the road than automatics, east and west Asia too and central and South America.
@@sterkriger2572 False, you are spreading lies and misinformation. Go look up the statistics, globally more cars have been Autos now for over a decade. No one cares about the EU, its a tiny ass part of the world that doesn't own many cars.
It's like in movies where everything happens in USA and they're "saving the world"
Black and Decker is for like making pilot holes in drywall. Use a real drill on speed 1 and it would do significantly better
this was the first video that made me sort of understand! thank you... this is so incredibly painful to learn
99 percent of automatic transmissions also use a torque converter… that would have been helpful to explain as well
The Torque Converter is more to transfer energy from the engine to the transmission(slippage 'till lockup) and to the front pump(direct connection as the T/C is bolted to the flexplate and the hub welded to it sit in the pump gear).
What he explained (grossly) in the video is mainly how A/T switch gears (ratios).
A/Ts are far more mechanical art than this 😉 hydraulic, mechanical, space maximizing and electric systems all in one box of 2×2×2 (i.e. th GM 6T70E)
Have a great Day sir ✌️
It's been 2 decades I'm trying to understand this thing. Still can't get much out of this videos
I watched a lot of videos on how auto transmissions work and have a fairly good understating of them. However, one thing no video has ever covered is how an auto transmission actually does the shifting from one gear the next and how it decides when to change.
That's super cool thanks for sharing
Loved it, thanks!
Okay, cool, but how does the car change gears automatically?
The only thing I don't understand is why YT recommended me this video. But that's a nice explanation that blow my basic knowledge of mechanics. Thanks
This is just a scratch of the surface of the automatic transmission. How does the transmission disengage when in drive but the car is parked? How does the transmission know when to change into a higher or lower gear? How does the reverse work?
another great video!
This description doesn't seem correct. If you release both the control gears, then when you apply load to the orange output, the red control gear will spin.
Very cool explanation
I vowed never to get an automatic-transmission car until I understood how automatic transmissions work. 17 years later and I'm still driving my '07 Mustang with a stick shift >.
Was really hoping to hear how the Torque Converter works.
I live in Canada, when I started driving it was cool to drive a manual car 😂.. once i got the hang of it i loved it, my little Honda i use as my run around car (my tundra is really hard on fuel) is manual, i love it. Best part is no one could drive it, so I don’t have to worry about it getting stolen either lol
LOL, I still have no idea how an automatic transmission works. I barely even understand how the gear shifting works, and I was watching you do that manually, not automatically. Still, it's fascinating and I'll study this some more until I actually understand it.
Is it considered automatic if your manually choosing and holding the handles to control the gears?
Common shaft for the sun gears is the classic Chrysler TorqueFlight transmission configuration.
Ok but can you explain how exactly car switches gears? Idea is clear but I would like to know what "forces" forces gears to switch
How is this thing available for free on YT?? Amazed me totally
The main thin i wanna know is what engages and lets the planet and sun gears move at different paces itself, like manual has the coupling that engages the gears
Thanks!
Many different variants on ‘automatic’. What your describing here is a conventional torque converter type automatic. There’s other automatics like DSG, for example. Totally different design
So I manually reach down and grab the gear I want to be in to make an auto work? A couple steps seem to be missing, like the automatic part. Still a cool demo of planetary gears.
It seems like it wound be pretty self explanatory. Just have a mechanism stop the gear.
Very educational video, although one thing I'd like to highlight: automatic does not equal automatic. I can list at least 5 types that are all considered automatic, but may fundamentally differ in the way the achieve what they do.
Great video!
Gonna be honest. I am more mesmerized by the quality 3d print of that gears
So in order to get more gears you add more planetary gears?
That’s really cool
“Almost all the cars on the road are automatic” That’s right, assuming there are no roads outside the USA. 😂
I’m sure there are roads outside the USA but who cares about those?
@@JamesSmith74740 As the usa falls lower and lower, losing influence and money, the counter question will soon be, who cares what's in the usa?
@@JamesSmith74740 More than 7 billion people cares for sure.
I'm fairly clear on the gear ratio part, but I'm confused about how this is automatic. What does the equivalent of "gripping" parts of the mechanism in an automatic transmission?
It's more so explaining the mechanics of the transmission since it's different from the mechanics of a manual. The terms "manual transmission" and "automatic transmission" tend to refer to the design of the transmission as much as the function. This is video does explain how an automatic transmission shifts, but it omits the information about any system that controls when it shifts, which is probably better off as it's own video.
A more accurate title would be "How A Planetary Transmission Works." But I bet most people are not going to be familiar with calling it that.
I read a thick car mechanic book twice, and I didn't understand this. But full disclosure, I'm not a professional or even amateur mechanic. Pretty cool, though!
thanks dude i was thinking how transmissions work in a car im wondering that for all day
We dont NEED automatic transmissions in out cars.we have gotten along just fine with manual transmission cars.
i think he meant why we need a transmission in our cars, not why automatic transmission is needed over any other type.
Okay so you have gears and a way to swap between them but wheres the part that actually switches the gears. When I drive I don't manually change a piece I'm holding to stop it from moving to change gears.
"Almost all cars on the road are automatic!"
*laughs in german*
Now I wanna know how automatic transmissions work.
Before this video showed up in my feed, I didn't care.
The biggest advantage of manual is that you can prepare yourself beforehand for the next seconds, you feel like more free and can adjust.
Disadvantage? Don't see any.
I don't feel comfortable with automatic, unfortunately I know its because i wasn't grown up with it, even though its simpler
So, an automatic transmission works by using a magic ghost? The ghost grabs onto a gear knob, which determines which gear ratio to use?
OR - you have glossed over the most confusing aspect: how it "Automatically" changes gear ratios.
I was about to make a correction about the frequency of automatic transmission, but I see the description did it before I could.
Well Done❣❣❣
Great video ! Using such colored 3D hand-sized parts realy helps to visualize and "feel" what is going on :-)
I would just have loved to see the other side of the mecanics while you were holding the blue or red part :-D
...and I cannot but wonder what would happend if you try to hold both the blue and red part at the same time ^^
I'm trying to figure it out in my head, but may need a bit of sleep ^^
Does anyone have an idea / a bet over what the result would be ?
It would stop the mechanism. Holding both gears at once would be the same as holding onto an axle going through the entire system (even though there isn't a continuous axle, I'm explaining it that way to make the concept easier to understand)
@@HelenaOfDetroit As someone who's job require to read a lot of unanswered tech questions describing exactly what is needed to make something works, I can only praise you for answering here despite the time! To anyone reading this: Be like Helena, you might save a Robin's sanity one day ;-)
Do you think you can print a SSS clutch?
damn, i don't get what tightly engages direct gear, as in why shouldn't yellow be able to rotate when orange has resistance?
How do forward and reverse fit in?
Gears are one of the coolest things humans have created. Fun to play with, watch, use.