gear train size

[Ilario]

I'm here with a new question. :

I should calculate a series of gears to transmit the bike in a mechanical timer, but sincerely I don't know well from where to start and especially what data I need to leave.... also in this case I have school notions that however little serve because you, they fill you with formulas that are definitely useful to solve the problem, but at school as a starting base to solve you everything without explaining why of choosing certain parameters rather than others.

for now I would like to focus on the transmission ratios, knowing that the last gear of the series will have to make 1 turn in 24h = 0.000694 rpm and that I do not work with big motors, but those small electric motors and I do not have huge spaces to be able to make who knows what wheels (we can say that at most I can have a wheel with a diameter of 50mm) from where I start to understand how many gears will need in the teeth, ?

I probably did not provide all the data necessary to the problem, but ask also since I do not know well the data I need at the start and I would like to understand this; how to get what I need.

Thank you.

 

[peloritano]

some data you already provided...
reepilogando
number of turns in the time of the final wheel
maximum diameter of the toothed wheel
missing the power that has the motor and the number of turns of the motor itself

 

[Fulvio Romano]

certainly is not a structural dimension.
have you thought or have the possibility to use at least one endless screw gear? It would give you the first, big speed reduction. Probably only one.

put the fast shaft on the endless screw, calculate the speed of one step of the screw, then, given the diameter of the toothed wheel, calculate the arc subdued by a step of the screw, and you found the number of turns of the wheel.

 

[Ilario]

some data you already provided...
reepilogando
number of turns in the time of the final wheel
maximum diameter of the toothed wheel
missing the power that has the motor and the number of turns of the motor itself

Okay, I imagined.... but based on what I choose these two data?

 

[Ilario]

certainly is not a structural dimension.
have you thought or have the possibility to use at least one endless screw gear? It would give you the first, big speed reduction. Probably only one.

put the fast shaft on the endless screw, calculate the speed of one step of the screw, then, given the diameter of the toothed wheel, calculate the arc subdued by a step of the screw, and you found the number of turns of the wheel.

no, first because the same engine will probably also need another set of gears, and second I should work with skewers and I can't.

 

[peloritano]

depends on the transmission ratio. . . .
large lines say that the final gear rotates at 1 lap per day I would consider it very slow.....
so if I choose a slow engine to get the right transmission ratio I will need a small (as number) gear train,
while if I choose a motor that rotates at high speed, I will need a very large gear train (always considered as the number of gears that make it up).
then finally I would choose a motor that rotates very slowly.
but still the power of a motor is given by the torque for the angular velocity, therefore a motor that rotates slowly will have to emit a large torque and therefore will certainly be of higher dimensions

 

[Ilario]

Therefore, I have a motor already reduced (motor) that we currently use to do this type of work that makes 1giro/min (ok we already use it, but I would like to understand from what you started to get to this engine and still I did not understand it). the engine alone would make 600giri/min with a power of 0.77w, once mounted the reducer makes me that blessed 1giro/min. I have underhand the technical sheet of this reducer (which will be the starting base of the engine gear of my series), which given I have to read to understand the power it expresses on the final pin?

I hope I explained.

 

[davide75]

Usually the reducer has the maximum incoming turns that can stand.the power always remains that since it is the product of the speed for the couple, so these are the two parmates on which you can act.

 

[MBT]

if the engine is from 0.77kw, the slow gear shaft will find 0.77kw * performance
the performance of the reducer depends on many factors, such as type of reducer (endless screw, parallel axes, epicycloidal...) and reduction ratio
say you can go from 25% to 90%...
If you have a reduction of 1:600, I would say that it is an epicycloidal to multiple stages, at least 3, so to nose.. .
I would say 60% performance

Usually the reducer has the maximum incoming turns that can stand.the power always remains that since it is the product of the speed for the couple, so these are the two parmates on which you can act.

That's not true.
a certain amount of power the "wake" to turn the reducer and win the internal friction

 

[Ilario]

Usually the reducer has the maximum incoming turns that can stand.the power always remains that since it is the product of the speed for the couple, so these are the two parmates on which you can act.

I on the limiter parameter, which seems to be the most important based on the technical sheet, wrote "spur reduction gearhead - gear torque - 3 kg-cm". Doesn't that mean anything?

 

[Ilario]

if the engine is from 0.77kw, the slow gear shaft will find 0.77kw * performance
the performance of the reducer depends on many factors, such as type of reducer (endless screw, parallel axes, epicycloidal...) and reduction ratio
say you can go from 25% to 90%...
If you have a reduction of 1:600, I would say that it is an epicycloidal to multiple stages, at least 3, so to nose.. .
I would say 60% performance


That's not true.
a certain amount of power the "wake" to turn the reducer and win the internal friction

No no, on the engine board says just 0.77w not kw...

You think if the gearbox tells me gear torque - 3 kg-cmCould this be the twisting moment? so if I thought well:

mt*omega = power

n = 1giro/minuto
3kg*cm = 0.3n*m
omega = n*2pi/60 = 0.1047 s^-1 (is it also right to rad/sec? )
p = mt * omega = 0.3*0.1047 = 0.0314w

Am I right?

 

[MBT]

which is a gear with straight teeth gears that bears a nominal torque of 3kg*cm =0.03 kg*m
What? ?

 

[Ilario]

which is a gear with straight teeth gears that bears a nominal torque of 3kg*cm =0.03 kg*m
What? ?

what's zf?

 

[MBT]

No no, on the engine board says just 0.77w not kw...

You think if the gearbox tells me gear torque - 3 kg-cmCould this be the twisting moment? so if I thought well:

mt*omega = power

n = 1giro/minuto
3kg*cm = 0.3n*m
omega = n*2pi/60 = 0.1047 s^-1 (is it also right to rad/sec? )
p = mt * omega = 0.3*0.1047 = 0.0314w

Am I right?

Sorry, but for me a motor under the kw is shaving stuff...
However, on such small gearboxes should be indicated the nominal torque, which is generally not used but uses a minor.. .
But the order of greatness is that!

 

[MBT]

what's zf?

a brand of precision epicyclical gearboxes with "regulatory" powers. . .

 

[davide75]

if the engine is from 0.77kw, the slow gear shaft will find 0.77kw * performance
the performance of the reducer depends on many factors, such as type of reducer (endless screw, parallel axes, epicycloidal...) and reduction ratio
say you can go from 25% to 90%...
If you have a reduction of 1:600, I would say that it is an epicycloidal to multiple stages, at least 3, so to nose.. .
I would say 60% performance


That's not true.
a certain amount of power the "wake" to turn the reducer and win the internal friction

you're right I forgot about the performance but cmq the substance does not change.

 

[Ilario]

a brand of precision epicyclical gearboxes with "regulatory" powers. . .

er... we do not produce machines of large size or with enormous efforts, so the order of magnitude is this.

the reducer is not epicycloidal is a reducer with within a series of gears (such as what I should accomplish outside and for which I opened the discussion )).

 

[Ilario]

Sorry, but for me a motor under the kw is shaving stuff...
However, on such small gearboxes should be indicated the nominal torque, which is generally not used but uses a minor.. .
But the order of greatness is that!

So, what I said with the calculations I did, my starting data for the power of the first gear is that 0.0314w?

 

[MBT]

Can't you mount n gearboxes in series? ? ?
I mean, the engine makes 600 rpm, so 864000 rpm per day
your reducer has 1:600 and takes you already to 1440 turns per day
one more with 1:600 six at 2.4 turns per day
with a pair of gears you can get ratio 1:2.4
but also with a toothed belt.. .

 

[peloritano]

Since we have someone could clarify what indicates the value of couple that is used to mark the reducer? ? ?