Nutation Wobbling Gears - Why Nobody Talks About This? 

Work it baby, work, work, work.

that was my nickname in highschool

That joke really *grinds* my *gears*…

out

Might as well make the gear teeth like the cycloidal gears as well.

Didnt know tapered roller bearings were for multi directional loads, explains why you see them in automotive drivetrain applications. Good to know thanks for the info

Slab bearings. Barrel shaped like old right axles on Mercedes swing axle

​@@jasonwhite2028 yes but they have a large nut or snap ring to hold it in place, so it's not the bearing on its own, and it's only in certain cars, possibly just trucks, I believe. The hubs of most cars are just a large straight bearing that gets pressed into the knuckle. While trucks and anything larger has tapered bearings that are made to come apart so you can pack grease into it and then pop it back together and fasten it down

I hear mention of tapered roller bearings mentioned around machinist lathes. Depending on what angle you’re cutting the load could be axial, radial or a mix of both.

So it’s possible to avoid the pulsing entirely if you design the gears to meet the constraints you described? I wonder if it would be zero-backlash like harmonic drives?

Recreate this with magnets. No friction.

I don't quite understand what you mean. Can you make a model in your workshop to illustrate the principle, and then upload a video showing how it works?

@@ParaBellum2024 That's a weird way to troll. 🤔🤨

@@mspeir i just looked at your channel bc i was interested if you had a workshop due to parabellums comment , you earned a new sub.

@@sayorancode I haven't posted in years, but thank you.

It's very much like on a worm gear reduction, friction takes away quite a bit of the performance.

This was my initial impression but actually I don't think this is a fundamental problem of the mechanism, but the tolerances/manufacturing of the part. Like, its not like contact is made to force the gear once per per rotation, the contact is made cyclically around every contacting gear tooth in rapid succession. I think that there are also ways to optimize the tooth design. Before involute gear tooth, the same (or similar) criticism could be made for simple gears!

​@@MatrixRay19I am unsure of this. I think at first glance you'd assume something similar of cycloidal gearboxes

I was thinking the same thing with the engage and disengage being horribly indirect compared to planetary or worm etc, but it also looks like it could be constantly engaged with just a portion of the gear as it wobbles rotating the contact position? Not sure but the vibration alone makes this seem pretty unviable, still cool to learn about

Maybe. But the real show-stopper is friction. Properly designed gear trains have friction only in the bearings but never on the teeth (rolling motion via evolute geometry). Here, there teeth are sliding into position. Big no-no in engineering and the reason why worm gears wear out so quickly.

Why do you say this doesn't involve deformation? The end plates appear to deform (this is most visible in the thumbnail design - the orange plates are clearly shifting, especially the output side). I'd be interested in a proper 3d model showing zero deformation necessary while maintaining constant output ratio & continual output torque - it's not obvious to me that such a design exists given the changing angle of the teeth.

@@TheLoneWolfling the plates are tilting not bending. If anything, the center tube is the one that should be deforming

@@wedmunds The outer plates cannot tilt relative to the center tube without deformation. And yet they clearly are tilting relative to the center tube. This implies deformation. You are correct in that the center tube could be deforming instead of the end plates; either way this involves deformation (my point).

If the materials choices were better deformation would be reduced or eliminated. Poor materials will cause deformation in any mechanical system, yet you seem to think it is a specific flaw to this drive? He even states in the video that as the materials are not solid it is deforming I suspect you only have the most surface level understanding of mechanisms. AND skipped most of the video.

@@backtoearth1983 Kindly stop with the unwarranted assumptions. The point of contact of the center cylinder with the outer plates shifts both axially and radially as the assembly rotates. And the gear extends a finite amount radially. It's easier to envision the problem if instead of treating the contact as two crown gears interacting, you unfold it 90 degrees and envision it as two spur gears interacting, where one spur gear has both a non-central axis _and_ said axle isn't square with the gear. This results in the contact point shifting both radially and axially. It shifting radially isn't the end of the world - non-circular gears do exist - however, it also shifting axially introduces an additional set of constraints between different planes of the gear. (Normally with a gear of finite width different planes of the gear are mostly independently constrained - see e.g. helical versus herringbone gears: you can effectively independently rotate each plane of the gear and still result in a valid (though potentially hilariously impractical) gear.) Non-circular gears are normally already fairly constrained. It is _not_ obvious to me that there exists a solution to the further constrained system, although I'd love to be proven wrong.

I'm struggling to understand what you mean. Can you make this design in your workshop, and then upload a video showing how it works?

I am not sure how to explain it, referencing 8:32 But if you install the right side transmission to be 90 deg out of phase with the left side, that will it switch which side does the pushing. Essentially you can smoothen the output motion by making it so that the push (instead of being in sync) happens twice per rotation instead, right left right left…

@@ParaBellum2024 bot

@@sayorancode Wot?

@@marco_gallone I'm not sure if you are referring to the smoothness of the axial movements. But if you picture the circular motion, your suggested offset of 90 degrees or pi/2 is equivalent to the sum of a sine and a cosine, which results in a larger amplitude, which means more axial vibration in both directions. Mathematically, as you know, only a phase shift of 180 degrees or pi will cancel. Here are two examples in Desmos: 'qfcs5camdc' (180 degrees) and 'kkvv0zanus' (90 degrees).

Exactly, the ratio increases as the number of teeth get closer together.

That's wrong. Checkout the harmonic drive or the cycloidal drive. They are zero backlash drives and require friction on the gears. Here's a good explanation of the harmonic drive: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-7QidXf9pFYo.html

That's not true. Involute gears have sliding and rolling contact. Pure rolling only happens at the pitch radius. Some sliding is a benefit in operation as it keeps the oil film from collapsing.

Even ideal evolute gears slide, this is plain wrong

Worm drives if properly designed with suitable materials and tribology do not wear out quickly. But it is so easy to make a badly designed worm gear.

@@zachary3777 Haha! Correct! Totally accept your response in the context of substantial forces & hardened steel surfaces. However, in the concept shown in the video, we are seeing a "dry" system built from a low-melting-point material. Here, we should aim at a system where we only see rolling motion & big radii if we want the system to survive for a reasonable time... self-lubricating materials would be a bonus too...

You're right something has changed, it is increasingly turning into brain rot, I assume that's what tiktok is like (I wouldn't know)?

​@@Mike-jm5wttried tik tok once, it's still 100 times worse, not even joking. Tho youtube is getting worse and worse and content farms are also responsible for that

Hopefully they move to one of the pop up competitors like odysee or something

Idk about the torque situation - I'd say it's only actually engaging on or two teeth at a time, a lot of other teeth are really close, especially the closer they are to the contact point but unless the gears are flexing, no additional teeth are actually making proper contact. I'd think a next step could be to compare and contrast the design to a planetary configuration to see if there are any benefits but it's definitely interesting either way.

It is not suited for high load. With a 45 degree tooth angle, the output force is equal to the bending force on the inner gear.

@@renedekker9806 because of the amount of surface area in contact between the gears, the load distribution on them is completely different than other gearboxes. That means that the gears can handle many times the force before failure. This thing is only made of plastic, imagine one made of metal. Optimizing this box would be a really fun project for me, if I had the means to do it

@@christiangray7826 _"because of the amount of surface area in contact between the gears"_ - the real contact is still only 1 or 2 gear teeth, the force concentrates on those teeth. Because the gear teeth have an angle, that force also tries the gear teeth to disengage. In a normal gear box, that force is towards the centre of the gear, which is easily withstood by the gear. In this gearbox, that force is perpendicular to the gear itself, causing the gear and its axle to bend. I would not put large loads on it.

@@renedekker9806 We disagree on its function, but doesn’t that make it even more interesting to see it tested to failure? Whether it performs well or not, it would be very fun to learn more about. Maybe it has no potential. Maybe it has plenty. Only one way to find out, and that’s optimizing it

This is more like a split ring planetary

Its a matter of use cases. Most of the time you don't need a planetary gear, but when you do its very useful to have. Same thing here, a worm drive is fine if you have the space. But if you are limited in space a design like this is nice to have.

3:45

@PrajnaDisciple dampeners work by removing vibration energy from the system and turning it into heat. That energy has to come from somewhere. The more vibrations there are the less efficient the gearbox is. Much better to use a rotating counterbalance shaft or design a system where the forces balance themselves out

whats better than gear teeth. yep tesla turbine disc friction gears without touching. either same axle or normal gear style, interleaved discs. there is just a very thin layer of air between many disc layers.

I think a bike wouldn't benefit since this is for very high ratios and bikes use almost exclusively overdrives.

Yeah, the basic idea of the differential cog numbers is the same. But their implementation is a bit more matured. Already used for driving robot arms, for instance. Still, this thing here is very interesting for illustration. 👍