samuele.vecchi
Guest
Hello, everyone. I would need an opinion (with any shortcomings/corrections) on the table of a component of an epicloidal gearbox (especially with regard to the choice of geometric tolerances).
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TETRASTORE
Guest
It is necessary to attach the design of the component.
meccanicamg
Guest
Good morning to you.
Did you read the rules? No.
Did you show up? No.
did you search the forum before posting? No.
Did you write in the right section? Maybe it was better in students, but let's forget.
You asked a question you didn't attach documentation to. We don't have the crystal ball, so can we help you? No.
basic rules of communication ...
samuele.vecchi
Guest
Good morning, everyone. I'm a mechanical engineering student. for an examination I dimensioned a two-stage epicycloidal reducer compact for robotic applications and I realized the table setting of the axieme and that of a particular (left plate of the satellite carrier - component 14). I have some doubts especially about the choice of tolerances in the design of detail. precise that the coupling between pin (component 9) and left plate of the hammer holder is forced with interference. I attach the two drawings and thank you in advance.
meccanicamg
Guest
Slowly we'll give you a look at things.
the legislation for roughness is evolvendo with symbols and roughness. personally I have not yet found a cad that supports the iso 21920 but the iso 1302:2002 is supported.
Solidworks settings.. .
now it indicates ra 0.8 below the root of the "carriola".
the use of the arrow attached to the symbol is a bit of a force and therefore to avoid.
but always, it has never changed, the tip of roughness is turned... and always insists on the surface worked, never on the opposite one.
Moreover they are more than 20 years that you no longer write "a-a-section" but you only write "a-a".
the contours are 0,5mm thick and the fine lines 0.25. there is the norm that defines this....iso128-20.
in the axieme, if the section is made with arrows to the left.... the sectioned view goes to the left not to the right.
it is not that everything that allows a software is in accordance.
the diameter of the piercers 72 should be tolerated otherwise the location is not enough.
the legislation for roughness is evolvendo with symbols and roughness. personally I have not yet found a cad that supports the iso 21920 but the iso 1302:2002 is supported.
Solidworks settings.. .
now it indicates ra 0.8 below the root of the "carriola".the use of the arrow attached to the symbol is a bit of a force and therefore to avoid.
but always, it has never changed, the tip of roughness is turned... and always insists on the surface worked, never on the opposite one.
Moreover they are more than 20 years that you no longer write "a-a-section" but you only write "a-a".the contours are 0,5mm thick and the fine lines 0.25. there is the norm that defines this....iso128-20.
in the axieme, if the section is made with arrows to the left.... the sectioned view goes to the left not to the right.
it is not that everything that allows a software is in accordance.
the diameter of the piercers 72 should be tolerated otherwise the location is not enough.
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samuele.vecchi
Guest
Thank you for the answer. I'm fixing.
TETRASTORE
Guest
for geometric tolerances you can take inspiration from the design on page 41 of this documentHowever, considering that the whole of the holes should also be tolerated.
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samuele.vecchi
Guest
Thank you for the answer, the document will definitely help. As for the interest of the holes, sincerely, I have no clear how to tolerate it. Do I refer to eligible deviations?
TETRASTORE
Guest
Yes, I as earth values 72 +/- 0.01.
meccanicamg
Guest
personally, that I am more focused on a practical approach, it is worth more a tolerance of ±0,01 and I would not place the location....but look good, it is right that both are there.
samuele.vecchi
Guest
I thank you again for the answer and for the kindness. I just wanted to ask for 3 more things:
1) is it correct to repeat the localization and parallel tolerances for the 2 holes (as done in the drawing) being different holes?
2) in the conical hole I used both a dimensional tolerance h7 and a geometric tolerance of circularity but according to you are both necessary or go only to weigh the design?
3) would it be appropriate to insert a roughness of 1.6 on the surface where the rosette rests and perhaps a dimensional tolerance in the hole diameter 6.5 mm where the screw passes or can I leave so?
1) is it correct to repeat the localization and parallel tolerances for the 2 holes (as done in the drawing) being different holes?
2) in the conical hole I used both a dimensional tolerance h7 and a geometric tolerance of circularity but according to you are both necessary or go only to weigh the design?
3) would it be appropriate to insert a roughness of 1.6 on the surface where the rosette rests and perhaps a dimensional tolerance in the hole diameter 6.5 mm where the screw passes or can I leave so?
meccanicamg
Guest
(1)
2) is the support of the satellite plug... the more precise and the less problems you will have of operation. both of you
3) if it is the area where the rosette rests not. If it were the side that keeps the pin on the team.
biz
Guest
a very serious thing is to indicate the drfs on axes, as well as tolerances. The axes are never touched.
Parallelism (on axes by the way) does not serve once you have defined the tolerance of location.
Parallelism (on axes by the way) does not serve once you have defined the tolerance of location.
samuele.vecchi
Guest
where I could reposition them
samuele.vecchi
Guest
good morning to all, I attach the modified drawings (never to change only the thickness of the lines). in the design of the component I moved the datum b on the external diameter of 90 mm (is correct?) in the main view and I reported the tolerance of perpendicularity to b (in place of and that I have eliminated why place on a board and probably also useless). I added the datum c in the section view and reported the localization tolerances to b and c. I finally eliminated the two parallel tolerances. I ask confirmation of the correctness of the changes and I gladly listen to further advice. I would have a last doubt about the geometric tolerance of location: I indicated this tolerance on the main view but I listed the holes on the view in section; to make it clear that this tolerance is referred to all 3 holes of the same type would no longer be appropriate to specify it somehow on the main view or possibly move the tolerance to the view in section? Thank you again in advance.
samuele.vecchi
Guest
I looked at the drawing of the document shared but according to what said by biz I seem to understand that there are several errors also in it. Right? I do not understand whether reporting tolerances and datum to axes is actually a mistake by norm or rather something to avoid preferably. I'm kind of confused.
TETRASTORE
Guest
is correct the statement of News; guard document to pag. 2-3 and, to expand your knowledge, also quest'altro on the recent gd&t standard.
In your case, using the datum b on the outer diameter, implicitly assumes also its theoretical axis for which for the three conical holes I would keep the localization tolerance referred to b and, at this point, I would remove the tolerance on the diameter (axis) 72.
the same you will have to do with the diameter (center) 12 h7. These two geometric localization tolerances would match the odds of the respective holes in the view in section, possibly indicating the number of holes.
observing the design of the component and the axieme I would like to make some comments:
- the depth of 0.5 mm of the 12 h7 centering is not functional, considering the bevel on your component and that on the counterpiece (necessary) you will find an unexisting centering.
- also the thickness of 1.5 mm of material where the screw m6 works seems to me to be small; You can increase them by reducing the height of the screw head (using low-headed tcei).
- from the overall it seems that when you fix your component (14) you have two references of jokes (12 h7 and 12.6 h7 conical) of which one is too much. if it acts first the conical is fine, but if it goes first in joke on the 12 h7 the conical tree is no longer stuck and being able to block them both at the same time is very difficult.
- I would also insert the angle of the holes that are not on the axles.
- I do not know how the male part of the centering on the counterpiece is obtained, but instead of three centerings of 12 h7 I would do only one to 82 h7 working also the corresponding counterpiece; this observation take it with reserve because I do not know how component 5 is made.
In your case, using the datum b on the outer diameter, implicitly assumes also its theoretical axis for which for the three conical holes I would keep the localization tolerance referred to b and, at this point, I would remove the tolerance on the diameter (axis) 72.
the same you will have to do with the diameter (center) 12 h7. These two geometric localization tolerances would match the odds of the respective holes in the view in section, possibly indicating the number of holes.
observing the design of the component and the axieme I would like to make some comments:
- the depth of 0.5 mm of the 12 h7 centering is not functional, considering the bevel on your component and that on the counterpiece (necessary) you will find an unexisting centering.
- also the thickness of 1.5 mm of material where the screw m6 works seems to me to be small; You can increase them by reducing the height of the screw head (using low-headed tcei).
- from the overall it seems that when you fix your component (14) you have two references of jokes (12 h7 and 12.6 h7 conical) of which one is too much. if it acts first the conical is fine, but if it goes first in joke on the 12 h7 the conical tree is no longer stuck and being able to block them both at the same time is very difficult.
- I would also insert the angle of the holes that are not on the axles.
- I do not know how the male part of the centering on the counterpiece is obtained, but instead of three centerings of 12 h7 I would do only one to 82 h7 working also the corresponding counterpiece; this observation take it with reserve because I do not know how component 5 is made.
samuele.vecchi
Guest
Thank you again for the answer. I attach the modified design. I added a datum d as reference for the tolerance of perpendicularity as it seemed more appropriate to take as reference the axis of the hole itself (is it correct?). I also eliminated the dimensional tolerance on the diameter of 72.
- I had already thought of moving the localization tolerance in the view in the section but sincerely I was a bit reluctant because I had never seen it do (I usually noticed that the holes are listed in the front view and in the same the tolerance is placed but in my case it is unthinkable to quote the holes in this view because it would be confusing).
- I am not convinced to add the number of holes because otherwise I should not do the same for the other odds like that of 6.5?
- as far as the first two points are concerned, I have understood and the speech comes back, so I will correct everything.
- I think I understand what you mean in the third point, but I don't know how to solve the problem: the conical hole I need for connection between the left plate and the pin that supports the hammer holder, while the other hole is necessary to connect the left plate with the right plate of the hammer holder and therefore designed to ensure greater stability.
- I did not understand the fourth point on the angle of the holes that are not on the axes.
I wanted to ask you one last thing: according to you is necessary a tolerance of flatness (and/or a narrower roughness) on the right side of the plate on which the shouldering of the pin rests before the entrance to the conical hole? I have not put anything at the moment as the support area is really small and I seem rather exaggerated to impose a further condition.
TETRASTORE
Guest
Yes, in fact the holes are few and easily recognizable.
see image attached. In reality it is understood that there are 4 holes at 30° but I think an operator is more facilitated if he sees it written.
