planetary for the axle?

[mike75925]

has anyone tried this? basically it would be off of the same premise as a rotary, the sprocket via the planetary will spin the axle 1.5-3 times faster than the sprocket is moving. it seems it would be the same as running higher gearing.

 

[motor_head]

so what would be the advantage of that over higher gearing i can't think of any, it would be less efficient too

 

[TurtleMann14]

generally you use a planetaries to reduce torque loads on the drive train
or to shift gears (automatic trans)

 

[mike75925]

i've seen them in high torque starters. are they there to reduce or increase torque?

 

[TurtleMann14]

well, either... depends on which way you install it
generally on heavy equipment they use them to amplify the torque (at the cost of speed) this reduces the load on the drive shafts, axles, and the transmission(the planetary is found in the hub of the wheel)

 

[mike75925]

the only time i have seen planetaries in a rear end was for differential. regular motorcycle starters are plain old motors, the ones for GL (opposed 4-6 cylinders) series hondas, use the planetary system. oh yeah, almost forgot, the motor would have to face the other way.

 

[TurtleMann14]

cat backhoes and excavators all use them in the "hubs"
most major pull trucks have them in the hubs


they are not really good for road use do to more fiction that they generate


you for got about winches, they have planitaries in them

 

[mike75925]

i've never taken a winch apart, so i wouldn't know. so the theory is sound, but it will need to be an oil bath setup, with 80wt, probably.

 

[TurtleMann14]

but why would you want to gear it down to gear it back up?

 

[mike75925]

you could run 2:1, hopefully, and still get a decent maybe 80mph topend?

 

[TurtleMann14]

i must not be understanding what you are trying to do....

so you have a sun gear on the axle and the sprocket on the outside, or the planetary ring?

remember there are more than 2 types of inputs on planetary gears

 

[mike75925]

the one i refer to has an inner gear, outer gear and satellite gears. the satellites work like ball bearings.

 

[TurtleMann14]

alright, but you can put power in on the sun gear the satellites or the ring gear
and you can also get power out of each of these

but one has to be held still (mounted to the frame or something)
or you could put a brake on it to change gears

 

[mike75925]

the outer gear is for the sprocket, the inner the axle. the satellites are for transition of energy in my approach. put a brake on it to change gears?

 

[TurtleMann14]

yea, if you install two you can have a changing gearing or neutral



ok, so in the planetary you are speeding up the axle(geared speed increase)

but the chain from then engine to the planetary is slowing the speed down (geared reduction)

ok, so why not just run the gearing from the engine to the axle and have less friction?(more potential power)

a planetary sacrifices speed for torque and visa versa

to human knowledge there is no way to use gearing to get more power out an an engine or motor. unless, there are multiple gears that keep the engine in its power band.

 

[motor_head]

ok, so in the planetary you are speeding up the axle(geared speed increase)

but the chain from then engine to the planetary is slowing the speed down (geared reduction)

ok, so why not just run the gearing from the engine to the axle and have less friction?(more potential power)

thats what i thought unless i missed something

 

[mike75925]

the axle's sprocket will turn at the same speeds as normal (6:1, or whichever), the satellites will drive the axle harder than the sprocket ever would. i do not see a significant loss on sprocket speed unless my tires are just too big. it's a matter of leverage, ( I feel a change in the wind says I, pirates of the carribean) anyway, it should be a torque multiplier. at the least a sleeper setup.

 

[TurtleMann14]

... but but when you get that torque you are loosing speed
and when you get that speed back you are loosing torque

 

[mike75925]

or would i have better torque for the speed i have?

 

[TurtleMann14]

no, it would be the same
what you put in is what you get out - friction