conical gears with straight teeth.

[Stefal639]

hi, my name is stefano, I am aquilano and study here from me mechanical engineering... already for years "bazzicavo" with these programs in a very jumpy way, but only to acquire small components of cars or motorcycles, that then we made to realize to the cnc, but it was always and only of simple objects, like the plates to distance the brake calipers, of the spacers for the quads or things of the race...
as an end-of-course examination we must report the complete reconstruction of each detail and the assembly of a mechanical assembly...I chose for the examination to bring the mechanics of an electric rifle to compressed air...the parts dismantled you can see in photohere are my first difficulties. ..I am not at all able to realize the big gear in the bottom (the three big ones you see, but also the pinion connected to the motor). ..as the exam is in January and the proffs still explain how to make the quarries or simple extrusions, I wanted to anticipate the work;-)
my main problem is the realization of the conical part...I don't know how and where to start...I tried to draw a profile of the "piena" wheel, writing the equation of the plane perpendicular to the tilt of the wheel and making a tooth sketch I got making a quarry a single tooth, but unfortunately it is not for nothing similar to the original...for the classical dense wheels with straight teeth I did not find any difficulty because before

to conclude my presentation: My dream is to work in a car prototype company.. .for years I design a prototype with tubular frame, including suspensions and other...because thanks to this wonderful faculty I learn how to "progetta" every now and then I take back the drawings and I always modify them + to get "perfect"... only a few months ago I discovered that practically my design exists almost identical in reality... his name is ariel atom;-) I have to say that the disappointment there was a bit,
cmq to conclude: Nice to meet you all. I'm sure I'll be fine.

ps: here is a photo of the gear and the point where I am.
for the most attentive: yes, I did wrong that part under the toothed wheel + high... I did it on the contrary.

 

[Stefal639]

Can no one help me? ?
You think with the loft you could do? ?
I do tooth sketch on a 30 degree slanted plane (effective tilt of the gear) and then on a 10 mm offset plane (length of the tooth) I make another sketch, scaled of the tooth....according to you can work? ?

 

[sampom]

Can no one help me? ?
You think with the loft you could do? ?
I do tooth sketch on a 30 degree slanted plane (effective tilt of the gear) and then on a 10 mm offset plane (length of the tooth) I make another sketch, scaled of the tooth....according to you can work? ?

I do not know catia, but that processing with all cad can be done quietly with cutting loft. make the starting and arrival sketches representing the profile of the teeth compartment and a sketch with the guide curve (it will be a segment between the 2 previous sketches) that follows the conical face profile/tilt. Cut a compartment and then make a circular repetition.

only one record:
for commercial/normalized elements it is not important to reproduce exactly the geometries (unless expressly requested for construction purposes.. in your case only those who make gears); you create a "solid" that "likes him" and that with the constraints possibly respect the laws of the bike.
Then there are all the characteristics for the purchase, which in the case of technical/mechanical standardization (such as gears) are also valid for construction.
and however these details are normally beautiful and ready in the cad libraries (such as the viteria), and wanting you can copy and edit them.

greetings
Marco:smile:

 

[Stefal639]

Thank you very much, same idea that I had, only that the internal sketch, that "immerso", will be a little difficult to create... then I will see:biggrin:

on the fact that the components are normalized, true, same thing that the professor told me, but the examination that I am supporting concerns precisely the reconstruction + faithful possible of the mechanical total that I chose.
then as a final part of my examination I would also like to do a fem analysis with gear ansis to see the less solicited parts in order to eliminate material to lower the inertia of the rotating bodies... talk about a 12v electric motor that turns to 35 thousand rpm and a mass (pistone) in alternate motion that makes 1800 rpm, so, in my opinion, can it really be a good thing to be able to do fem analysis to limit the