dimensional rotating system

[Stefano Rufini]

good morning to all and good start of weekend.
My name is stefano and I am at the last year of the master in mechanical ing.
I would like to compare with the forum about this project I am following during my internship.
This is a new case for me and outside the standards of teaching design.
to perform treatments in the workshop, it is necessary to rotate a body (orange in the image) of almost cylindrical form, positioned on a sloped plane of 30°. the rotation axis coincides with that of symmetry.
It is a body with a maximum diameter of 900 mm and a weight of almost 150 kg.
the rotation speed, after an initial acceleration, will be very low: it is estimated about 5 rpm.
This last design requirement has led me to neglect the inertia (first doubt) also because there is no need to have a sharp acceleration in the start.
this is the draft of the scheme of the rotation system.being in the preliminary phase I did not optimize the geometries, especially of the tree, and I did not insert some elements that will be fundamental for the positioning of the bearings (ghiera, distantial. . ).
my main doubt concerns how to place the forces (the two weight strength components, the couple at the pulley...) to be able to dimensional the central shaft and to choose properly the bearings.
the pink pulley would be fixed to the particular green, so it would be a case of fixed and external ring instead rotating.
I thought I'd treat the detail in green as a framed beam.
after which I would echo the axial and radial force components on the two bearings, considering a radial effort only on the lower and composite bearing on the second b.

 

[meccanicamg]

the green piece as a lace can not be a beam. the bearings inside it you will have to bind them. If you choose to make an isostatic, you will have a bearing that reacts radial and axial while the other only radial.
all will be assimilated to a single body to determine the reactions to the bearings.
then if you want to calculate the reactions to the various interfaces is a different thing.

 

[Stefano Rufini]

Meanwhile thank you for the answer. Yes, as I wrote at the end, I thought to consider the bearing in a with only radial stress (vaxy) and one in b with both radial stress (vbxy) and axial (ob). I still have to examine how to bind them. It would be my intention to move to this stage after determining the equivalent load on the two bearings. But I got stuck in getting the stresses in a and b. the only body as you mean it?

 

[meccanicamg]

I mean that the various pieces you can consider them a welded, for the calculation of reactions.
If you consider the reactions you said it means that the bearings are mounted in an isostatic way.
the pulley also generates shooting.
You have to break down the weight force.

 

[Mattymecc]

In my opinion the only thing you can treat as a beam is the component you drew in blue, the tree. You must have treat the yellow, green and pink components as a rigid body bound to the shaft by means of the two bearings, which you will have to work one as a zipper and one as a cart. calculations the reactions of the constraints of the "hard body" subjected to the various forces and then change of sign you put them on the tree and the size.

 

[Stefano Rufini]

In the meantime yesterday I had elaborated this design and these calculations. I agree with your observation. next step will be the verification of the central tree. this element I can consider it as beam because it is the only fixed to the main plate