Why Gear Teeth Have This Shape

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music by @TheJustinator

[MeWhne]

No unnecessary babbling ✅
Straight to the point ✅
Easy to understand ✅
Good Illustration ✅

[pedro_the_melon]

I love how the video is a perfect loop

[kadenielsen]

Love involute gears. The force vector along an involute is always pointing in the same direction as well, super useful in making sure your system is stable and not wobbling. Also, constant surface contact with no discontinuities (like square-tooth gears), so no snapping or sharp corners for stress concentrations to occur. Smart stuff, another cool engineering application of mathematical properties.

[bradley-jamesnorris]

Thank you for ruining my sleep lol, loving these shorts but im addicted now!

[idiot-tzgq]

What stays the same is the component of the difference in position of the contact point and the center of the powerd gear that is perpendicular to the normal force between the gear teeth. Sure the contact point moves away from the powered gear but the lever arm doesn't actually change because the force between the gear teeth isn't tangential to the powered gear. There isn't any actual pushing back to make-up as he says; This way there would be much more friction than there is in reality. Another thing to point out is that the point of contact moves along a straight line which is the dual of the forces that I've described. This gear tooth profile is the involute of a circle. Imagine wrapping a string around a circle and winding or unwinding it to produce the shape. In a way the string of one tooth feeds into the receding string of the other tooth producing the straight line of contact and constant gear ratio.

[ckush]

Please revisit this as I'm pretty sure it's incorrect. Gear ratio stays constant in an involute profile, that's the whole point of that shape. The angular velocity ratio is also constant and does not change like in the animation.

[xenontesla]

This video is a little misleading. The gear ratio is always constant (look up the "law of gearing").
Gear teeth are curved in a special shape called an involute so that they have a constant gear ratio even when they're not perfectly spaced . The contact forces also happen to align in a straight line!
Non-curved gear teeth wouldn't even mesh...

[kayakMike]

Here I thought it was intended to avoid vibrations and a noisy gear train.

[randomname]

Great videos! Another fun fact: the contact point (for involute gears) travels along a straight line. This reduces vibration if I remember correctly

[patrickmcglone]

The involute profile is chosen for most gears because it causes the pitch point to travel along a straight line (the pitch line) during contact, and so that it ensures strictly rolling contact instead of sliding contact. This reduces efficiency losses from friction, and makes it so that the gears can last a whole lot longer.

Additionally, the pitch line angle can be manipulated to alter characteristics such as tangential loads, and minimum number of teeth.

[imv]

you know you makeing all these into those super cool trendy loop shorts make these a lot harder to digest

[Bikerbuoy]

Your video demonstrates that the involute tooth profile maintains a constant radial clearance between the engaged teeth.
In simple terms, this prevents the two gears from 'rattling'.

[noidea]

I love how i understand more from these videos than from what i am studying at school

[Gdroku]

I remember watching a documentary about Archimedes and how he built an odometer for the Romans to mark the miles on their roads. It was so simple and sophisticated that DaVinci could not replicate it. The trick was in the shape of the gear teeth; Davinci used gears with square teeth, which did not work, while Archimedes used pointed teeth like in this video.

[IMUTNT]

Its this shape that the turning-speed (of the gears) is constant.
If u had an other shape the wheels would accelerate and slow down with each tooth.

The shape is called "involute"

[monkeyfat]

wow, never new that. i thought it was just easier to do a circle/oval than a square, and it did nothing for the gears, but that vary ivariesesting. thank you❤

[swealf-nonofficial]

I know some people have already mentioned this but what is explained here is incorrect. The contact point between the two gears moves in a straight line while maintaining constant speed: this ensures a constant gear ratio and no slipping between the teeth, it's one of the main advantage of such gears. You could think about it like a pulley system, where the rope has a constant speed between two pulleys, it's essentially the same principle. If you want to see it for yourself, search "gear action line animation" and you should find something that will explain it better than I did.

[hdhsu-dgfb]

i honestly thought it was for easier meshing of the gears reducing wear and making the overall motion/balance? smoother

[Quorox-]

I didn‘t even realise it looped and watched the video twice, so great job 😂

[alectriciti]

Man this is a long short. There's just no end but I'm learning so much!