dimensioning pinion rack and motor

[meccanicamg]

I am doubtful about the 6 w... 1111 n strength and 3 mm/s speed give a value of about half, but it should be evaluated the system's start and stop transients take into account forces and pairs of inertia.
However, it must also indicate hardness and depth.

for discourse heat treatment we are talking about surface tempering to induction 56/58hrc that also a c45 pre reclaimed, quality square meters iso 6336-5 (equival to agma grade 2), for a minimum depth of 0.7mm up to a maximum of 1.2mm, can reach.
Of course you get half. in the excel sheet I used a factor then 1.5 and then I arrive almost double. Surely transients with accelerations will be decisive.

 

[TETRASTORE]

I saw this old discussion and I should make a statement.
in reference to this post:

the net power of the load is about by previous calculations wc = 5,6kw.
the service factor according to certain shocks was considered ks= 1.5.
the performance of the mechanics was considered 90%.

the installed power to the engine is:
wm=wc•ksη=5,6kw•1,50,9≈9,3kw wm=\frac{wc•ks}{\eta}=\frac{5,6kw•1.5}{0,9}≈9,3kw wm=ηwc•ks=0,95,6kw•1.5≈9,3kw

from catalog of red engines to 4 poles we have that the motor immediately available for excess is 11kw.

considering only the modes of choice of the driver based on these data (which were resized in previous posts), I wanted to specify the influence of the service factor in choosing a gearbox.
if the power required by an application to use is 5.6 kw, the power to the engine is obtained by dividing it by the transmission performance, in this case 0.9, so you will have the required power to the engine = 5.6/0.9= 6.22 kw, then you will choose the engine with the next unified power that is 7.5 kw.
the reducer must be chosen according to the required power to the increased engine of the service factor: 6.22*1.5=9.3 kw.
summarizing, the nominal power of the engine will be 7.5 kw and the reducer, at the corresponding nominal speed of the engine, will have to admit in input 9.3 kw.
the service factor is always referred to the reducer and not to the motor whose power is influenced by the type of service s1, s2, etc..

 

[Mattymecc]

I challenge the tetrator post to have some clarification on the topic service factor (fs) on which I had already asked questions in the past. . .

to the technician when it was about dimensionaling something (straws, chains, gearboxes...) took the power required by the machine, calculated taking into account the yields, and multiplied by fs.

fs we were looking for it on tables from time to time proposed by the manual of mechanics rather than by catalogues etc...

now my perplexity:

1) What does fs represent? is a dimensional coefficient, so I can say that it is the ratio between the maximum peak power required by the user and the nominal power "media". . .

2) is there a rule where indications are given for the estimate of fs based on the application?

Finally, if a dynamic study is conducted for a certain application and the value of the maximum peak power is obtained, for example, in the start-up phase without fs? ? ?

 

[meccanicamg]

the factor of service or factor of oversize is nothing but the relationship between couple, forces in play, powers that are in "effective calculation" version than (fract) those "nominal".
a reducer is calculated more or less in a homogeneous way but it is not always true. maybe yields the bearing or gear first... and that represents the nominal torque of the reducer.
in those operating conditions lasts the calculation hours.
if you have bumps, accelerations, variations, you get an average weighed equivalent load (see miner) that lives used for calculation.
therefore it is as when it comes to load si disversamento and tension si von moses. the relationship between the two firbhsxe security bills... Same stuff.
the peak powers do not fall into the nominal, unless it is a defined cycle and therefore the effective value is calculated.

 

[meccanicamg]

granny defining service factors for table applications is agma 514.02 and similar.
Actually it depends on the real application and these indications also become overflowing for many applications.

 

[Mattymecc]

first of all thanks for the answer, and for the table of the agma standard concerning the factors fs.
miner can be useful when designing limited life, I don't know if you can use it even when designing unlimited life.. . .
I look better on niemann if from some indication. . .

 

[meccanicamg]

miner rule serves for calculation of the weighed average power.

If you need it for infinite evaluation, you must have an average number of cycles that you play 2*107 or the limit you want.
However even if high numbers of cycles, you have to impose them otherwise you do not compute anything.