cylindrical gear to helical teeth

[Davide Costantini]

Good morning, everyone. I ask a direct question to which you answer with an espresso number in millimeters: if a cylindrical tooth sprocket has z=18 (number of teeth) and mn=5 (normal module), is there a possibility to trace back to the value of the primitive diameter of the pinion?

I will be wrong, but by adopting the classic equations of cylindrical toothed wheels I find myself always having two unknowns in the same equation. Unfortunately I have no other information (such as the angle of inclination of the teeth) as in an old 1998 distinction I found only the number of teeth and the normal module. Of course if the teeth were straight the primitive diameter would be 90 mm, in this case instead?

I hope I have posted the question in the correct forum and put the matter well. Thank you all.

 

[Stan9411]

depends simply on the slope angle of the tooth.

 

[Davide Costantini]

That's right. so game over because it's an information I don't have.

 

[Stan9411]

in my very short experience 99% of the time is 20°.... but I would expect an experienced user to help you.

 

[meccanicamg]

you have to use a caliber specifically to find the corner and then you have to measure the wildabler because it could also be corrected the profile.

 

[Davide Costantini]

This is a component of a separate 1998 I do not have the opportunity to touch it by hand, to make the necessary measures. so without the tilt angle of the teeth you do nothing. thanks to the prompt answers.

 

[Davide Costantini]

problem solved: I managed to trace back to the rack that geared with such pinion. from the catalog of the gudel I found the angle of inclination of the propeller (19° 31' 42") that must be the same as the pinion. from which:

primitive_diameter = mn*z/cosb = 95,367 mm

thanks to all of the answers.