I know this is an older video but I am hoping it is still monitored and you can help me out here. I have went down the bit hole of planetary gears and have watched several different videos and I am confused by what I think is conflicting information (more likely me just misunderstanding) From online the gear ratio from sun to stator/carrier GR = 1 + (number of ring teeth/number of sun teeth). I believe the gear ratio also = driver speed / driven speed. In the case of a locked ring gear, and using the teeth number from your examples, the gear ratio, GR, for from sun to stator would be = 1+ (100/20) = 6. If it is also true the GR = driver speed / driven speed, then the stator rotational speed would then be = driver speed / 6, or 16.667%. In your example, you arrive at the fact that the stator is rotating at 40% of the sun, which is different. Can you possibly clear this up for me? Like I said, I figure I can chalk this up to my misunderstanding but I like answers haha
Nate, thanks for the inquiry. The number of teeth will indicate the ratio because they are all tied together. Check out this article mentoredengineer.com/calculate-planetary-gear-ratios/ and others on mentoredengineer.com for more information on this subject
so if i have the diameter of ring gear, how can i find the number of ring teeth, sun diameter, sun teeth, planet teeth and diameter. i tried to find some information about internal gear but the don't have the formula to solve the teeth, module... can you help me out.
I’ve seen illustrations where none of the 3 gears are fixed, thereby allowing for an even greater reduction for the ring gear. In reality, if we allowed all three axes to move freely, would that ring gear ratio remain constant, thereby allowing that free spinning ring wheel to act as a secondary input to drive another object? I presume that this depends on what that ring gear is driving and the torque required. Or am I looking at this the wrong way?
David, That is the same concept used in automatic transmissions. Check out these videos where I look deeper into this subject. In the second video, the sun drives 3 separate systems and the ring is held stationary based on the desired output speed. czcams.com/video/imp3le0DCXs/video.html&lc=UgwhQbyC00zl2pVnQ9F4AaABAg czcams.com/video/V10Kx9vpdmI/video.html
@@MentoredEngineer Thanks. For some reason I thought that the compound systems all involved a fixed plane of rotation. The illustration I saw had the sun, planets, and ring moving. I'll look at your videos again and see what I missed. Another question: if we're not dealing with high torque applications, why aren't belt-drive or pulley systems using this? I only found one video on youtube which came within close approximation of this (titled "inverted timing belt transmission"). Last question: I've seen compound planetary systems illustrated whereby they're arranged parallel to one another using shafts. Are there system which achieve compound advantages, but instead of utilizing a secondary separate gearset, add more planets? In other words, instead of: sun - planet - ring, they would consist of sun - planet - ring - planets - ring, or some variation thereof? Or would the additional mechanisms cancel out a mechanical advantage as they're essentially being used as idler gears? Thank you so much for taking the time to respond.
David, As far as the pulleys, they are a wear item and need to be tensioned. This means more parts. One of the main benefits of planetary gears is the coaxial shafts. The inverted timing belt transmission is a cool idea. The other cool thing about planetary gears is that you can make complex systems do cool things. You probably could do the configuration that you were proposing, but it might be difficult to control the motion by holding the right things. I'd dive deeper into this and see if others have tried it. If not, maybe you can patent it!
@@MentoredEngineer thanks again. I’m borderline flabbergasted there isn’t more information and talks on CZcams about this ubiquitous marvel of an invention. For the rest of us non-engineers, I assume planetary gear mechanisms are just scratching the surface of simple, yet impressive marvels of engineering? I realize we all have finite time so take my request with a grain of salt, Have a great night!
Ok I bought my kid a planetary gearbox set. Surely I’m missing something..... The rings are stationary and there are two different planet and sun sets. One sun has 12 teeth and the 3 planets have 18 teeth. The ratio states 5:1 I figured (3*18)/12= 4.5:1 The other planet sun set is 3 planets with 16 teeth and a 16 tooth sun with a ratio of 4:1 Again (16*3)/16= 3:1 Can someone explain this??? Btw the toy is tamiya 72001 Thanks for any help
Johnny Jr, Thank you for your inquiry. From the pictures online, the system looks like a 48 tooth ring gear that is stationary. Based on the universal gear equation with S=12, P=18 and R=48, one input from the sun will give 0.2 rotations of the carrier which is a 5:1 ratio. This video should help. czcams.com/video/imp3le0DCXs/video.html. Let me know if you still have any questions.
@@MentoredEngineer thanks for the reply. The video cleared up a lot of questions and also left me with more to think about . There is definitely more to it than I thought. It may not be in your plans , but it would be awesome if you had a basic engineering course on YT or Udemy for teens interested in engineering.
Johnny, I'm glad that that video cleared things up for you. I'm curious as to what you mean by "basic" engineering? I find that what I call basic is generally boring in nature or has been covered well enough that I have nothing "new" to offer. Please check out the website as well mentoredengineer.com Thanks for your feedback. -Corey
@@MentoredEngineer oh I definitely didn’t mean boring and basic was probably not the right word. I meant more like a STEM course for everyone. Tech Explorations has a web site and few courses on Udemy. Just about anyone can follow along with ease and learn how to program an Arduino, learn the basics of C language , understand electronic components, build electrical circuits and learn about EE without experience. Another great one is Programming electronics academy . Their course is more heavy on learning to program an Arduino than Tech Explorations . One that had potential but we passed on for a lot of reasons is Jetpack academy. Mark Roper has a ME 30 day camp for all levels. From what I understand, depending on your age, it gets as challenging as you make it. I’m sure with your knowledge, right content/projects and your personality, you could reach a large target audience.
Johnny, Thanks for explaining. As mentioned, I don't think that I can offer anything new in this space. I really wanted this channel to be a resource for engineering graduates so I do assume the ability to do algebra and basic engineering principles (statics and dynamics). I was considering putting together a "redneck" structural engineering course, but the market seems to be narrow and there could be liability issues. I've already been burned on 2 courses. (I'm really surprised at the lack of interest in the roller coaster design course).
Thanks for the comment. Check out these other videos I've made on the subject. czcams.com/video/imp3le0DCXs/video.html czcams.com/video/V10Kx9vpdmI/video.html czcams.com/video/0Eu5nvEyUeg/video.html czcams.com/video/VMK6yB-fE8k/video.html
Amazing content. You just saved my day. Keep rocking.
Glad to hear it! Let me know if you have other questions
@@MentoredEngineer You're welcome
@@MentoredEngineer if any one want to design epicyclic gear system from where to start and which parameters to consider ?
Tanaya, check out these two videos.
czcams.com/video/imp3le0DCXs/video.html
czcams.com/video/V10Kx9vpdmI/video.html
wow i finally understood thanks a lot!
Great! Check out these videos as well.
czcams.com/video/V10Kx9vpdmI/video.html
czcams.com/video/imp3le0DCXs/video.html
I know this is an older video but I am hoping it is still monitored and you can help me out here. I have went down the bit hole of planetary gears and have watched several different videos and I am confused by what I think is conflicting information (more likely me just misunderstanding)
From online the gear ratio from sun to stator/carrier GR = 1 + (number of ring teeth/number of sun teeth). I believe the gear ratio also = driver speed / driven speed. In the case of a locked ring gear, and using the teeth number from your examples, the gear ratio, GR, for from sun to stator would be = 1+ (100/20) = 6. If it is also true the GR = driver speed / driven speed, then the stator rotational speed would then be = driver speed / 6, or 16.667%. In your example, you arrive at the fact that the stator is rotating at 40% of the sun, which is different.
Can you possibly clear this up for me? Like I said, I figure I can chalk this up to my misunderstanding but I like answers haha
Nate, thanks for the inquiry. The number of teeth will indicate the ratio because they are all tied together. Check out this article mentoredengineer.com/calculate-planetary-gear-ratios/ and others on mentoredengineer.com for more information on this subject
so if i have the diameter of ring gear, how can i find the number of ring teeth, sun diameter, sun teeth, planet teeth and diameter.
i tried to find some information about internal gear but the don't have the formula to solve the teeth, module... can you help me out.
This video has some better information on planetary gear calculations. czcams.com/video/imp3le0DCXs/video.html
I’ve seen illustrations where none of the 3 gears are fixed, thereby allowing for an even greater reduction for the ring gear. In reality, if we allowed all three axes to move freely, would that ring gear ratio remain constant, thereby allowing that free spinning ring wheel to act as a secondary input to drive another object? I presume that this depends on what that ring gear is driving and the torque required. Or am I looking at this the wrong way?
David,
That is the same concept used in automatic transmissions. Check out these videos where I look deeper into this subject. In the second video, the sun drives 3 separate systems and the ring is held stationary based on the desired output speed.
czcams.com/video/imp3le0DCXs/video.html&lc=UgwhQbyC00zl2pVnQ9F4AaABAg
czcams.com/video/V10Kx9vpdmI/video.html
@@MentoredEngineer Thanks. For some reason I thought that the compound systems all involved a fixed plane of rotation. The illustration I saw had the sun, planets, and ring moving. I'll look at your videos again and see what I missed. Another question: if we're not dealing with high torque applications, why aren't belt-drive or pulley systems using this? I only found one video on youtube which came within close approximation of this (titled "inverted timing belt transmission"). Last question: I've seen compound planetary systems illustrated whereby they're arranged parallel to one another using shafts. Are there system which achieve compound advantages, but instead of utilizing a secondary separate gearset, add more planets? In other words, instead of: sun - planet - ring, they would consist of sun - planet - ring - planets - ring, or some variation thereof? Or would the additional mechanisms cancel out a mechanical advantage as they're essentially being used as idler gears? Thank you so much for taking the time to respond.
David,
As far as the pulleys, they are a wear item and need to be tensioned. This means more parts. One of the main benefits of planetary gears is the coaxial shafts. The inverted timing belt transmission is a cool idea.
The other cool thing about planetary gears is that you can make complex systems do cool things. You probably could do the configuration that you were proposing, but it might be difficult to control the motion by holding the right things. I'd dive deeper into this and see if others have tried it. If not, maybe you can patent it!
@@MentoredEngineer thanks again. I’m borderline flabbergasted there isn’t more information and talks on CZcams about this ubiquitous marvel of an invention. For the rest of us non-engineers, I assume planetary gear mechanisms are just scratching the surface of simple, yet impressive marvels of engineering? I realize we all have finite time so take my request with a grain of salt, Have a great night!
If we dont know inner gear's diameter and we have the Info about other gear's diameter.how to find inner gear's diameter ?
The equation is S+P = (R+S)/2; The variables are the number of teeth. S= Sun, P=Planet, R=Ring
This guy has to be related to John Goodman.
Not that I know of......
Ok I bought my kid a planetary gearbox set.
Surely I’m missing something.....
The rings are stationary and there are two different planet and sun sets.
One sun has 12 teeth and the 3 planets have 18 teeth. The ratio states 5:1
I figured (3*18)/12= 4.5:1
The other planet sun set is
3 planets with 16 teeth and a 16 tooth sun with a ratio of 4:1
Again (16*3)/16= 3:1
Can someone explain this???
Btw the toy is tamiya 72001
Thanks for any help
Johnny Jr,
Thank you for your inquiry.
From the pictures online, the system looks like a 48 tooth ring gear that is stationary. Based on the universal gear equation with S=12, P=18 and R=48, one input from the sun will give 0.2 rotations of the carrier which is a 5:1 ratio.
This video should help. czcams.com/video/imp3le0DCXs/video.html.
Let me know if you still have any questions.
@@MentoredEngineer thanks for the reply. The video cleared up a lot of questions and also left me with more to think about . There is definitely more to it than I thought.
It may not be in your plans , but it would be awesome if you had a basic engineering course on YT or Udemy for teens interested in engineering.
Johnny,
I'm glad that that video cleared things up for you. I'm curious as to what you mean by "basic" engineering? I find that what I call basic is generally boring in nature or has been covered well enough that I have nothing "new" to offer.
Please check out the website as well mentoredengineer.com
Thanks for your feedback.
-Corey
@@MentoredEngineer oh I definitely didn’t mean boring and basic was probably not the right word. I meant more like a STEM course for everyone.
Tech Explorations has a web site and few courses on Udemy. Just about anyone can follow along with ease and learn how to program an Arduino, learn the basics of C language , understand electronic components, build electrical circuits and learn about EE without experience.
Another great one is Programming electronics academy . Their course is more heavy on learning to program an Arduino than Tech Explorations .
One that had potential but we passed on for a lot of reasons is Jetpack academy.
Mark Roper has a ME 30 day camp for all levels. From what I understand, depending on your age, it gets as challenging as you make it.
I’m sure with your knowledge, right content/projects and your personality, you could reach a large target audience.
Johnny,
Thanks for explaining. As mentioned, I don't think that I can offer anything new in this space. I really wanted this channel to be a resource for engineering graduates so I do assume the ability to do algebra and basic engineering principles (statics and dynamics).
I was considering putting together a "redneck" structural engineering course, but the market seems to be narrow and there could be liability issues. I've already been burned on 2 courses. (I'm really surprised at the lack of interest in the roller coaster design course).
please redo with Ring = Sun + 2 * Panet for Teeth
You equation is correct. It is just an algebraic restatement of what is already in the video.
No clear understanding and no clear drawing
Thanks for the comment. Check out these other videos I've made on the subject.
czcams.com/video/imp3le0DCXs/video.html
czcams.com/video/V10Kx9vpdmI/video.html
czcams.com/video/0Eu5nvEyUeg/video.html
czcams.com/video/VMK6yB-fE8k/video.html