dimensioning dentate wheels

[rickimaracas]

Hello everyone, I am an engineering student and I am carrying out a project regarding the change of the wasp but it mounts a cylinder that dispenses about 27 kw to 11500 g/min. the first stage (primary transmission) has a transmission ratio 2,55(27/69). the second stage instead has: 1°marcia 5,8(10/58),2°marcia 3,86(14/54),3°marcia 3(17/51),4°marcia 2,56(19/49). you could help me in the dimensioning of the toothed wheels as by making a first verification I return a higher module than expected (incompatible with the encumbrance).
I attach a transmission pattern and the characteristic curve of the engine.
thanks in advance

 

[meccanicamg]

Bye. At least you have to post the clerk you need and we'll see what we're doing. also the width of gear band would be appreciated.
Besides, can you tell us how you did the calculations? Do you use any norms or are we still at lewis and hertz at the basic formula?
then gears are straight or helical teeth?

 

[rickimaracas]

I apologize for being unclear. are gears to teeth rights; the width of the wheels is:
1 March 12 mm, the other 8 mm. the intersection is: 1st stage 72 mm; 2nd stage 68 mm. for calculations I used lewis and hertz, which for the first stage are verified both, while for the second stage I return a major module, so I can't move on.

 

[meccanicamg]

Okay. then we see at the second stage to dimensional the first gear to try.
power input calculation = 27kw
First gear input regime = 11500/2,55=4510rpm.
I don't even have it, especially wear. Are you sure the whole thing is right? are not measures from "student" and then are they really not?

from your card is a p200e so going qui...we have 12,35cv at 5700rpm....it's 9kw.
still remains something that is not right in the data....modulo 2 but does not hold.

 

[rickimaracas]

I did not measure it, but I measured the diameters (external) of the quadruple and the other wheels and I returned:1° 24,5mm; 2nd 33mm; 3rd 40mm; 4th 44mm; hence I imagined that the module was 2 according to the number of teeth.
It is an engine developed for this results that power.I also see that in so many cases similar to this the same shaft is maintained for that I can not explain it.

 

[meccanicamg]

Actually, the first stage can't bring the 27kw to that intersection. it would be module 1.5 but it does not wear it by pressure.

 

[meccanicamg]

I did not measure it, but I measured the diameters (external) of the quadruple and the other wheels and I returned:1° 24,5mm; 2nd 33mm; 3rd 40mm; 4th 44mm; hence I imagined that the module was 2 according to the number of teeth.
It is an engine developed for this results that power.I also see that in so many cases similar to this the same shaft is maintained for that I can not explain it.

the quadruple should be module 2 also for me....but it crumbles.
How many miles did it take? Do you use it on the track? Do you change pieces often?

 

[rickimaracas]

They are pieces that are used on the track so seen the great powers do not make so many km, in fact what I had tried to do was precisely decrease the life cycle.
the material I used is the 18 crnimo 7-6.characteristics:
core hardness (hrc) ≥ 30
treatment: cemented
surface hardness after treatment (hrc) 61
rm: 1200 mpa
rp0.2: 850 mpa
and: 206000 mpa
σflim: 500 m
σhlim: 1500 mpa
with this material for primary transmission I checked out.
according to you considering a n° of low cycles in wear is ok as verification?

 

[meccanicamg]

They are pieces that are used on the track so seen the great powers do not make so many km, in fact what I had tried to do was precisely decrease the life cycle.
the material I used is the 18 crnimo 7-6.characteristics:
core hardness (hrc) ≥ 30
treatment: cemented
surface hardness after treatment (hrc) 61
rm: 1200 mpa
rp0.2: 850 mpa
and: 206000 mpa
σflim: 500 m
σhlim: 1500 mpa
with this material for primary transmission I checked out.
according to you considering a n° of low cycles in wear is ok as verification?

It's the same material and the same conditions I used.
Don't give me "shes" ...I'm not a mummy yet?
surely it is necessary to consider a low number of life cycles because however wear is and will be visible.
the problem is that in the operation of a change it is necessary to consider an average behaviour of its march that of power but here we are out a lot.

despite the calculations there is no sufficient length, having given me the measurement of the outer diameter of the pinions, we could determine the profile shift.

first stage pair:This is the first march:This is the second march:This is the third march:that is the fourth frame:

 

[rickimaracas]

I tried to make a wear check considering a number of average turns and a duration of about 100/200 hours and in this case they are verified. I also have very high equivalent tensions.
if you can change a bit the widths of your teeth you say that can be verified?

 

[meccanicamg]

I tried to make a wear check considering a number of average turns and a duration of about 100/200 hours and in this case they are verified. I also have very high equivalent tensions.
if you can change a bit the widths of your teeth you say that can be verified?

the increase in width of band b contributes to the strength of the tooth. therefore the more wide and the more door.
but do you have to make a change to physical pieces?
If you widen everything there is nothing in the carter and then you have to think about making the change.

 

[rickimaracas]

a change to the physical pieces I could also make it I could try to adapt it, of course I can make small changes. already widening the thickness of the wheels you could improve something, in diameter it is hard unless you try to lower the height of the tooth

 

[meccanicamg]

the company malossi has developed the kit very maniacal and with the teeth bombing just to increase the resistance. according to me only with the tools that offers kisssoft you can make a real optimization of the gears because the application is very push, out of the limit.

 

[rickimaracas]

I heard an expert in the field, and he told me: you can increase the width of another 1-1,5mm.
Another important fact is to differ from the canons 20° of the pressure angle to give more robustness to the tooth.
Finally you play with the relationships and relative corrections of the teeth in order to obtain tozzes in the most delicate points, without compromising the functionality exaggerating with the corrections.
I had seen this soft kiss program but I don't know how to download it. Can you? ?

 

[meccanicamg]

I heard an expert in the field, and he told me: you can increase the width of another 1-1,5mm.
Another important fact is to differ from the canons 20° of the pressure angle to give more robustness to the tooth.
Finally you play with the relationships and relative corrections of the teeth in order to obtain tozzes in the most delicate points, without compromising the functionality exaggerating with the corrections.
I had seen this soft kiss program but I don't know how to download it. Can you? ?

look on the site that there are two versions: a trial and a trial. read well. If you are a student you can also contact them directly and explain to them the situation....magari also jumps out a technician who gives you two straights.

 

[rickimaracas]

I found a software that calculates the geometry of the wheel with all the calculations.I tried to make a verification both to wear and fatigue following the norms and maybe I managed it.
I changed the relationship using for the first 13/55 with width 15 and 9/9,5.
Would you be able to see if the software is verified with you?
Thank you very much

 

[meccanicamg]

from how I understood you used the me-bac calculator and as from the report you attached there is only and exclusively the flex assessment according to lewis.
with width b=15mm of pinion and wheel you have the following:definitely now you have a more balanced flexion behaviour and therefore lewis is better. having brought the pressure angle to 30° we improved the tooth wear.
However the results provide the information that will be used to wear the tooth side even if it does not break down.

attention however because the pinion actually has greater width of the wheel conducted and therefore the carrying capacity is the smaller width of the two....so 9.5mm.obviously lowers the coefficient to bending and wear especially of the pinion.
However we are still far from overcoming the positive values of iso/din norms.
you can maximise using profile shift also enhancing the best contact pressure.... .improves but miracles do not.
So there's work on it. I repeat....only kisssoft will give you valid values and tools to push you so in detail and with a high prediction, including the fem on your teeth.

 

[rickimaracas]

tomorrow I will try to contact them then, trying to answer me and help me.
However varying the angle I noticed that some data change for example hf sf alfa1, with small variations of the angle I saw that these coefficients vary a bit, if I worked on this by changing some parameters, for example is better when they increase?

However the results provide the information that will be used to wear the tooth side even if it does not break down.

Does the tooth not break in the sense that the relationship of lewis is verified? if I lower the number of hours(I saw you entered 5000)maybe 500/1000

 

[meccanicamg]

surely small touches help to get to the optimal solution.
You should try to lower the hours but the fact that you turn to 4500rpm are many and you are still in the unlimited life range.
the only software that gives you the duration calculated based on data (and not set the hours on the contrary) is kisssoft that with the iso 6336 updated 2007/2008 and are reliable. Unfortunately with my excel sheet so built I can not push myself any further.

 

[rickimaracas]

So I contacted kisssoft and they told me that they will contact me in Italy! while I'm still changing a few things: I saw that I can still increase the thickness from 9.5 to 11, plus I managed to lower the maximum bending effort to the tooth base.
Can you check if this data is still far from the iso verification?
Thank you again and I apologize for the trouble.