when designing mechanical sizing of machinery organs, bearings, wrenches, tabs, toothed wheels. .

[Mecpro]

hi to all my name is an alessio, I am a student of engineering and I follow you often on this forum, the very short question I wanted to propose to you, was simply this, when the design of mechanical dimensioning of organs of machinery to es trees, bearings, sticks, tabs, dentate wheels, spindles, hydraulic cylinders and tires, etc. and when, instead, the various mechanical organs should only be chosen from any standard commercial suppliers unlike a design x mechanical dimensioning... because I have a miserable confusion about it to understand when they are to be sized or chosen... some have told me, in addition to reading in the various posts published here on the site, that if it were heavy machinery then it should be considered and therefore the mechanical dimensioning, otherwise not... let me know in the various post... thank you still alessio. .

 

[F_Ingrasciotta]

an analysis of the loads of stress of each component must always be done, then if you choose the way of the commercial it happens that the load that must bear the piece is congruent with the datasheet supplier, otherwise if the piece is drawing it is dimensionally and fatigued.

the document with all the analysis of the loads and the relative commercial choice/dimensioning must be drawn up (in 99%) and ends in the technical dossier for possible certification c.

 

[Mecpro]

I still don't understand. . i.e. when the piece must be drawn or chosen by a commercial? I did not find the clear answer.. .

 

[F_Ingrasciotta]

I still don't understand. . i.e. when the piece must be drawn or chosen by a commercial? I did not find the clear answer.. .

you will never have an answer, they are business choices that are executed according to the type of piece and at the cost.

For example, a screw you will never think of drawing it when you find the commercial. ...

 

[Mecpro]

usually then mostly, what are the cases where more often you design and size it to design and ad hoc any kind of mechanical component, for example starting from a helical wheel screw since you mentioned the example? or dense wheels, bearings, wrenches, trees, and away? maybe if you could list me a possible case of more frequent types where usually they are always designed and dimensional to fatigue and even statically any kind of mechanical organ... so I made an idea when they are designed or selected by a supplier. . .

 

[F_Ingrasciotta]

commercial:
- mechanical minutery (vitations, nuts, washers, etc.)
- rolling/roll bearings
- seals (see oring and similar)
- standard connection elements (keys, tabs, grooved profiles etc...)

drawing everything you can not find on the market, however both for very "spinte" applications or particular even those that turn out commercial common can be designed by white sheet.

 

[wert]

try to document on the web on the "make or buy" and you should find the answer to your questions.

 

[Mecpro]

so also commercial applications can be calculated and sized?? I still continue in the dark of the night della

 

[wert]

so also commercial applications can be calculated and sized?? I still continue in the dark of the night della

no, those calculates the manufacturer, providing you with the data sheet where you find all the performance and possible safety coefficient they adopt. your task will be to identify the commercial component that suits you. This obviously involves having to perform calculations, but only for the proper size (size) of the commercial component. Also for a ball bearing, which no one has ever built in the house, you have to calculate the loads to which it will be subjected and according to the tables of the builder, you will have to choose the most suitable for your application.

 

[MassiVonWeizen]

before you make calculations that applications require (to move the cart or lift the machine I need x strength; to turn and support 'shaft I need x energy and y load; to start the mechanism I need x current etc...).
then you look for the organ that can perform that function (motor, gulf, hoist, cylinder, bearing, screw, etc...)
then you look for between or producers what meets the requirements.
if it does not exist or is not convenient for various reasons then it is designed with relative calculations.

 

[Mecpro]

before you make calculations that applications require (to move the cart or lift the machine I need x strength; to turn and support 'shaft I need x energy and y load; to start the mechanism I need x current etc...).
then you look for the organ that can perform that function (motor, gulf, hoist, cylinder, bearing, screw, etc...)
then you look for between or producers what meets the requirements.
if it does not exist or is not convenient for various reasons then it is designed with relative calculations.

and what are these reasons

 

[MassiVonWeizen]

and what are these reasons

and what do you care now that you are a student of what these reasons are? the answer you were looking for: a component is designed when commercially does not exist or is not convenient.
when you are in an office to meet customer, business, purchasing office, production department and other more or less important figures you will find out.

 

[Stan9411]

You're rolling on something that's trivial. .

when designing mechanical sizing of organs of machinery, bearings, wrenches, tabs, toothed wheels, spindles, hydraulic cylinders and tyres, etc. and when, instead, the various mechanical organs should only be chosen from any standard commercial suppliers unlike a design x mechanical dimensioning

there are standard components, such as screws, nuts, bearings, o-rings, toothed wheels, which is useless to produce by itself. but they go somehow chosen for your application. This choice must be made thanks to calculations. often the supplier submits tables that allow you not to physically do the calculations.

example: bearing -> enters table
manufacturer with the loads and speeds to which it will be subjected (information that you can only know you designer) -> exit the table with the bearing size (diameter and band width).
always a calculation is. only that you exploit the work of one who put himself there and summarized everything in a table.

a catalogue of trees does not exist (that I know). because it is not a standard component.. can be 100 mm long or two meters, with 2-3-10 shoulders, with key seat, with a thousand rows, with thread etc. etc.

So, just like for commercial components, you calculate it.
only that unlike the commercial components you also have to draw it. And then give it to produce to someone or make it yourself at home.

therefore the question “when the calculation of standard mechanical components is made?” is nonsense, because the “dimensioning” is always up to you both with standard and customised components. . only you can know what load a screw is under. only that to choose the screw that holds that load does not need to start from physics1, since there is a catalog that has already made the calculations for you.

 

[Mecpro]

You're rolling on something that's trivial. .



there are standard components, such as screws, nuts, bearings, o-rings, toothed wheels, which is useless to produce by itself. but they go somehow chosen for your application. This choice must be made thanks to calculations. often the supplier submits tables that allow you not to physically do the calculations.

example: bearing -> enters table
manufacturer with the loads and speeds to which it will be subjected (information that you can only know you designer) -> exit the table with the bearing size (diameter and band width).
always a calculation is. only that you exploit the work of one who put himself there and summarized everything in a table.

a catalogue of trees does not exist (that I know). because it is not a standard component.. can be 100 mm long or two meters, with 2-3-10 shoulders, with key seat, with a thousand rows, with thread etc. etc.

So, just like for commercial components, you calculate it.
only that unlike the commercial components you also have to draw it. And then give it to produce to someone or make it yourself at home.

therefore the question “when the calculation of standard mechanical components is made?” is nonsense, because the “dimensioning” is always up to you both with standard and customised components. . only you can know what load a screw is under. only that to choose the screw that holds that load does not need to start from physics1, since there is a catalog that has already made the calculations for you.

so since according to your experience there are no cataloged trees, so there are no catalog gears, or even if they exist, can they often be designed according to the value of tooth correction that I want to give them according to their interasse? how to es gear reducers if besides choosing from a supplier preferably they can also often be designed ad hoc by a designer?

 

[Stan9411]

you write a dangerously similar way to another user.......

However, yes, the dense wheels are a middle way. in the sense that they are standard, but they are often the very basic ones. If you want special profiles, you may not find them.
therefore, if it is not in the catalog, one if it can calculate, draw and make ad hoc.

instead no one will ever make you an ad hoc bearing. you must adapt to what is in the catalog.

 

[MassiVonWeizen]

so there are no catalogue gears, or even if they exist,

here, before you get so many mental saws start looking on the net the various components that could be from trade because gears make them (to stay in Italy among the best known):potatositclearancereginasti

often can they be designed according to the tooth correction value I want to give them based on their interasse?

you always return to the same speech: Your calculations for the operation of the project tell you you need a particular gear? Then you size it, you draw it, you produce it.

 

[Mecpro]

here, before you get so many mental saws start looking on the net the various components that could be from trade because gears make them (to stay in Italy among the best known):potatositclearancereginastiyou always return to the same speech: Your calculations for the operation of the project tell you you need a particular gear? Then you size it, you draw it, you produce it.

I understood Massivonweizen thank you

 

[PIETRO2002]

Careful. In my opinion, someone's back lying to me.

 

[Mecpro]

Careful. In my opinion, someone's back lying to me.

what is scusa?

 

[PIETRO2002]

what is scusa?

principles = number of threads of an endless screw