tolerances, roughness and quarries for tongues

[Fizzy93]

Hello everyone, this is my first discussion and I am happy to have found a forum for designers who can ask for a hand
I am at the first year of mechanical engineering in modena (as already mentioned in the presentation) and I would need a hand to understand some things. the prof have assigned an exercise in which it is necessary to represent a tree, given an overall, and subsequently, to quote, insert geometric and dimensional tolerances, roughness and finally, to dimensional the seats for the tabs and for the elastic ring.
So, I well represented the tree, I also quoted the diameters but I have a problem regarding the rest of the exercise. I know it's a lot, but I want to figure out how to do it for the rest. As regards tolerances, I know how they should be written but I do not understand how to decide them:/ as regards roughness, I do not know how to decide roughness and, for the offices of the tabs and for the elastic ring, I cannot guide myself in choosing the quarry and the right ring. I ask only a few tips to get to the solution of the exercise.
Thank you very much to those who will answer.

ps: I also attach the tab for the tabs that I have tried to use.

 

[davide75]

on the baldassini tells you that pairings use depending on whether you want the brush planted/free.
try to guiarda them in the meantime

 

[sampom]

tolerances and roughness are based on what will be coupled on that tree area, application type and functionality.

as mentioned, in manuals it is explained in general what are the "standard" couplings for the various mechanical components.
also in the catalogs of "technical components" (cuscinets, seals, elastic rings, tabs etc.) are indicated the required tolerances... in the meantime, consult those and then explain better what your specific case is.

 

[maca75]

Hi.
As for your tree, you need to understand what and where it will be mounted in a specific area. then ask you what the requirements of this coupling are, it can be free, forced, etc and the assembly world of the assembly itself.
As already suggested, baldassini is a great source to find tables, and also references for the application of quotas, I also recommend the skf site that can help you in choosing tolerances and roughness to be applied in bearing areas.
for the "seeger" elastic rings you can find also in the net tables that indicate the size of the snow caves.
then probably by browsing your drawing book you will have some similar example from which to draw to understand with what criterion tolerances and roughness are chosen (attention also to the fact that there is a "relation" between tolerance and wrinkle obtainable ved. baldassini for example).
You will lose some time in research but this will benefit you:finger:
Hi.

 

[PierArg]

Hello and welcome.
First of all, I quote all those who preceded me.

regarding the design you posted:
- Careful, you also represented the seeger ring. You can delete it because you don't care.
- You only quoted the diameters. And the rest?
- the roughness you have to put on the basis of the work that will have to be used for its realization.

I guess you don't know what baldness is... don't worry because it's normal...

I also imagine that your greatest difficulty at the moment is to apply geometric tolerances and especially the cursed "number" that accompanies them...this is also normal


I attach a file with the roughness table according to the work that will definitely be useful to you

 

[Fizzy93]

davide75, thanks to the advice, I will certainly look on the baldassini, that I know to be a good manual
sampom, I imagined it was necessary to know the operation of the machine on which that tree will go, but, as an expert who I am, how do I understand the operation of the component?? Is it enough to inform me? ?
maca75, I also thank you for the advice, especially of the site skf, which I had been advised also by the prof. only problem, I can not orient myself in that site >.<
pierarg, I was so caught by the anxiety that I only quoted the diameters and nothing else xd I will quote the rest, then I thank you for the roughness table that will undoubtedly come back useful
Fortunately I know what the baldassini is (if you asked me a few months ago I had no idea what could be xd) and it is precisely the story of the "number" for the tolerance that worries me most.
I thank everyone again for the precious advice you gave me and try to put me at work

 

[PierArg]

that "roba" there smile is a sympathetic orthogonal and double-stage gearbox.

see here for a general consultation:
http://www.cad3d.it/forum1/showthread.php?t=33781&highlight=riduttore+assi+ortogonaliread the comment #7 of good mechanicsmg

 

[MBT]

maca75, I also thank you for the advice, especially of the site skf, which I had been advised also by the prof. only problem, I can not orient myself in that site >.<

actually the skf site is a little ostic, especially if you do not have clear ideas on what to look for

here you find the general principles for the application of bearingshttp://skfwebtools.com/gc6000/iec?maincatalogue=1〈=it&newlink=1_0_70here the general principles for radial locking of bearingshttp://skfwebtools.com/gc6000/iec?maincatalogue=1〈=it&newlink=1_0_72here the choice of couplingshttp://skfwebtools.com/gc6000/iec?maincatalogue=1〈=it&newlink=1_0_73here the recommended couplingshttp://skfwebtools.com/gc6000/iec?maincatalogue=1〈=it&newlink=1_0_74and here some indications about roughnesshttp://skfwebtools.com/gc6000/iec?maincatalogue=1〈=it&newlink=1_0_77:mixed:

buon lavoro! :biggrin: