[https://www.youtube.com/watch?v=jRn5waE0qfk&ab_channel=BrickExperimentChannel](https://www.youtube.com/watch?v=jRn5waE0qfk&ab_channel=BrickExperimentChannel)
Does the size and amount of cogwheels increase the torque?
please.
PS: This is some next level LEGO, cool AF!
In: 3
The torque is being provided by the motor itself. The extra cogs and structure are providing a stability to more evenly distribute that torque across the Lego structure, as any machine which wishes to give out that much force must also be able to withstand it in some way
Yes, definitely. If the motor turns a small cogwheel with, say, 8 cogs and the small cogwheel turns a large cogwheel with, say, 40 cogs, which turns the steel axle, the torque turning the steel axle will be 40/8 = 5 times higher than the motor torque. However, the RPM of the steel axle will be only 1/5 of the motor RPM. So you gain torque but lose speed.
If you add another similar pair of cogwheels, the torque will be further increased by a factor 5, so in total the torque turning the steel axle would then be 5*5 = 25 times the motor torque, but again the RPM would only be 1/25 of the motor RPM.
The size of the cogwheels does matter. If the large cogwheel would have 64 cogs instead of 40, the torque would be 64/8 = 8 times higher. If you’d decrease the small cogwheel, the torque would also increase, 4 cogs e.g. would mean 40/4 = 10 times higher torque. Or 64/4 = 16 if you simultaneously increased the large cogwheel. If the cogwheels have the same size, the torque will be unchanged (obviously since e.g. 8/8 = 1). If the second cogwheel was *smaller* than the first, the torque would *decrease*. So if you switched places of the cogwheels, the steel axle torque would be 8/40 = 1/5 (or 20%) of the motor torque (but it would be spinning 5 times as fast).
This is pretty basic stuff and used in many, many applications. This is the whole basis for transmissions in cars, bikes, any vehicle really. In first gear, the engine spins a small cogwheel, which turns a large cogwheel. This means that the torque that turns the wheels is much larger than the torque the engine provides (or your feet if you are riding a bike). However, despite the engine spinning really fast, the wheels turn slowly. Conversely, in a high gear, the torque turning the wheels may actually be lower than the engine torque because the engine is turning a large cogwheel, which in turn turns a smaller one. But then again the engine does not need to spin fast for the wheels to spin fast (or you don’t need to pedal like crazy).
Using but a few pairs of small and large cogwheels, you can get huuuuge torque from the smallest of motors, but the speed will be almost zero.
Edit: Cogwheels next to each other on the same axle do not increase torque. He just does that because the plastic of the lego would otherwise start to deform, so he needs to spread out the forces onto several cogs. In the video at 1:11, you can simplify the setup conceptually by imagining the two motors as only one with double the torque, and then there are only two cogwheel pairs that multiply the torque.
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