Visited MIT and learned about reduction gears

[Big Rig]

Delivered some windows to MIT so I have all day as they unload

Went to the MIT museum

 

[Big Rig]

So how does this reduction thing work?


All gear combinations are same size with one small gear solidly connected to a large gear, correct?


Small gear spins faster than large gear because it has shorter diameter but teeth of larger gear is going at same speed as teeth of smaller gear, correct?

So when small gear spins larger gear of adjacent gear set should not the speed of the larger gear remain consistent with the previous larger gear?

 

[Big Rig]

totally blew me away

 

[Big Rig]

 

[FAST]

YEP,...what would we do without torque multiplication.

FAST

 

[Big Rig]

YEP,...what would we do without torque multiplication.

FAST

So how does this gear reduction thing work?


All gear combinations are same size with one small gear solidly connected to a larger gear, correct?


Small gear spins faster than large gear because it has shorter diameter but teeth of larger gear is going at same speed as teeth of smaller gear, correct?

So when small gear spins larger gear of adjacent gear set should not the speed of the larger gear remain consistent with the previous larger gear? therefore there should be no reduction in speed (or change in torque) ?


Clearly I am wrong but what is wrong with my reasoning?

 

[JohnHenry]

The tip speed of the gear is not the same as the rpm. That is, a single tooth on the smaller gear only has to travel 1/4 the distance of the larger gear for each revolution. So if the tip speed is the same for both gears (they are meshed) then the rpm of the larger gear is 1/4 that of the smaller gear.

 

[Big Rig]

The tip speed of the gear is not the same as the rpm. That is, a single tooth on the smaller gear only has to travel 1/4 the distance of the larger gear for each revolution. So if the tip speed is the same for both gears (they are meshed) then the rpm of the larger gear is 1/4 that of the smaller gear.

so this means when the speed is translated to the smaller gear that smaller gear goes 25% as fast as the previous small gear and so on and so on

 

[FAST]

YA,...I would think that one has to look at this apparatus as a series of gear reduction gear combinations, a whole bunch of gear reduction boxes in series, with the shafts not obviously continuous.

FAST

 

[JohnHenry]

Just guessing. Assume the input is a standard 1728rpm motor, and 1440 minutes per day and 365.25 days per year
The motor turns 908858880 rev/year. With 24 gear sets at 6:1 the final block turns at 1 rev in 5213550136 years

 

[Big Rig]

Just guessing. Assume the input is a standard 1728rpm motor, and 1440 minutes per day and 365.25 days per year
The motor turns 908858880 rev/year. With 24 gear sets at 6:1 the final block turns at 1 rev in 5213550136 years

it takes the time of the universe since the universe began to turn the last gear 1 rev (13.7 billion years) 13,700,000,000 years

the artist implanted the last gear in cement to emphasis this point

that is why it is called the big bang




BTW, I also went to an atheist group that meets every Tuesday (open to public)

four students showed up so I made five as we ate total junk food - empty carbs and calories of the worse kind. I would have thought they understood nutrition. :doh:


Some of the worlds brightest students go there but you cannot tell by looking


which of these students looks dressed for success ?

Typical MIT babes

BTW, MIT pranksters stole that cannon from Cal Tech which Cal Tech has reclaimed and have now chained down

Has gone down s one of the great "hacks''

they have hacking rules

placing stuff on the dome is a typical hack

 

[TheShadow]

Hey,Big Rig!!!
How did you get in that pic with the babes?
Back row,far right.