vertical shaft size

[Domenico Garofalo]

good evening to all;

I propose to you the problem of the sizing of a vertical shaft to be used as a means of transmission of the motion between a motion-reducer and a vertical load applied to the other end. the shaft rests on an axial bearing and is aligned with two radial bearings. its overall length should not exceed 20cm for encumbrance issues. the end part of the shaft must be threaded to allow fixing with a structure below (practically screwing the end part of the shaft in the structure and stopping it under with a nut). Moreover, since the shaft has to drag the structure in rotation, one or more quarries should be laid to place thorns or wrenches.
data:- torque moment max (consistent combination in time) mt = 62 nm
- max length 20cm
- weight of the applied load (max traction load) p = 1430 n
- acceleration of inertia (resp. vertical axis z) to(z)= 1,57 rad / s^2
- rotation speed (constant) w = 15 rpm
- steel material
problema:- determine the minimum diameter of the "dmin" tree


would you recommend the right approach to the problem and perhaps advise me on setting equations?


thanks in advance to those who will answer or read only this discussion.

 

[MassiVonWeizen]

from the top of my ignorance in calculations I can only tell you that material:steel does not allow to have data to make calculations.
the term steel identifies a material composed of iron and carbon plus additional elements; the variety of these elements and their determining percentage characteristics of steel. you will understand that if you do not specify the type of steel you cannot know the mechanical characteristics such as yielding, tensile strength, torsion resistance; If you choose a 16mncr5 you will have completely different values if you choose, mistakenly, a s355jr

 

[meccanicamg]

I would say that first you need a pattern, even hand-made and you have to put your forces on it and let us understand how the system is.
If it is a vertical shaft and has the axial frame I imagine unilateral... and two radial bearings....would not change bearing system so we remove one?
steel....leave to us the free choice to range from s275jr to a cemented 17crnimo3?
budget?
If the bike is given by a reducer you take it to a hollow shaft? Shall we put the tab?
on the side of the load together with the thread it takes a tab otherwise it is unscrew... or other system.

 

[meccanicamg]

the data lacks the time of inertia of the section.... because you have the acceleration but without j you do not calculate the inertial effect....unless we neglect it and we hold as maximum torque absolute the 62nm.

 

[meccanicamg]

other thing.... 140kg if they fall kill someone or fall into the protected area?
this serves as discriminating to understand whether to apply the norms relating to lifting loads or whether to use only common sense and traditional methods of calculation.
also how many starters per hour does the gearbox?
Are there any bumps in the system?

 

[meccanicamg]

if the mounting scheme is like the one I proposedwe have the pure torsion generated in the tree tract with tab at the top (inserted in the gearbox) and continues to the tree tract below with tab (to be inserted in the hole of the mass to be rotated).

using the two opposing swivellable roller bearings arranged to or We will have the addition of pure traction in the stretch between the two bearings to descend to the thread where the nut will close the whole.

the morality of the fairy tale, if the thing is so, the most sensitive diameter is the lower one with tongue, keeping the jump of the diameters indicated by drawing.

but this you can see if you correctly analyze the tree and doing the graphics of the internal actions (you know how? diagram beams, forces, reactions, trace diagrams, see areas with overlapping of internal actions, worst section, calculation voltages according to diameter, von mises and comparison with admissible sigma).

Are you a three-year university? What are you doing? give us more background info so we can give you more targeted advice.

 

[meccanicamg]

just to put numbers, if you have traction of 1430n and a constant pair of 62nm, without peaks, without accelerations you have to evaluate the tau of twist and the traction sigma and comporle with von mises.as we do not know the type of application we make a safety factor 5 on the yield, as it is done for the lifting organs in general.
we take a steel c40 of medium characteristics and consider a yield load of 400mpa.
from this simple account comes a diameter of 19mm.considering that we have to insert the tab seat, we have to increase the diameter of the depth... which is about 22mm.

I repeat...this is statically with the assumptions I wrote. if instead there is a slice of torque button due to the start/stop it is considered the fatigue in the tree where there will certainly be a connection radius to be evaluated and possibly also verify the seat of the tab if it was subjected to traction button.

 

[meccanicamg]

just to have an idea, if I have to get at exit 15rpm and at least 62nm, I went to select an endless screw reducer of red reducers.Its dimensions are the followingand as you can see, its output hole of the reducer is a diameter 24mm.
In fact it is a reducer that is able to provide something more than 62nm and therefore it is made with that diameter that however turns out to be in line with the minimum diameter that we have calculated in the rest of the tree.
I attach the complete adapter of the reducer for vertical use in v5. possibly you can take flanges and various accessories for fixing.

 

[meccanicamg]

for those who want to use the gear-reducer indicated to the previous post to make a calculation of gears of the reducer, it is possible to split the gear in a precoup to cylindrical wheels helical with reduction ratio i=3,5 and a subsequent jump with worm and helical wheel with reduction ratio i=25 as indicated by the manufacturer.

the stage at helical wheels is likely the following:deduced that the stadium vsf / Rolled is likely the following:

 

[meccanicamg]

for the bearings of the vertical shaft, of which he spoke in previous posts, using the adjustable conical rollers you could opt for this:and carrying out long-term verification with the new skf tool we have:with the following characteristics, and especially lgem2+ep fat due to very low rotation regimen.with the shortcomings indicated here:so I would say that the chosen bearings are eternal.

 

[meccanicamg]

if the mounting scheme is like the one I proposedView attachment 55593we have the pure torsion generated in the tree tract with tab at the top (inserted in the gearbox) and continues to the tree tract below with tab (to be inserted in the hole of the mass to be rotated).

using the two opposing swivellable roller bearings arranged to orView attachment 55594We will have the addition of pure traction in the stretch between the two bearings to descend to the thread where the nut will close the whole.

the morality of the fairy tale, if the thing is so, the most sensitive diameter is the lower one with tongue, keeping the jump of the diameters indicated by drawing.

but this you can see if you correctly analyze the tree and doing the graphics of the internal actions (you know how? diagram beams, forces, reactions, trace diagrams, see areas with overlapping of internal actions, worst section, calculation voltages according to diameter, von mises and comparison with admissible sigma).

Are you a three-year university? What are you doing? give us more background info so we can give you more targeted advice.

Thinking about it is better to configure x of conical roller bearings so I can correctly counter the load.
we can always space the two bearings so it increases the tipping resistance.

What is important is that the bearings in the reducer also collaborate, but the intention is to use the gearbox hole to center properly but not to bear the bearings of the reducer itself the load.

 

[meccanicamg]

just to give you something more real to look at, I attach you a step made with freecad where there is the red gear motor, two conical roller bearings, a main shaft and the nut. Obviously missing the plate that holds the bearings on the external track from embluding to the flange of the reducer and possibly a lid. In front of the bearing, you have to put a spacer and then put your load on it.
you could make orange spacer with larger external diameter... .
the length of the shaft then you handle it according to what you want and you can keep the bearings away, from the thickness of the object to drag and from the fact that you want one or two normal/lowered dice etc.

now the shaft in total is 215 mm long but keep in mind that 90mm are inside the gearbox.

 

[meccanicamg]

just for a counter-proof, as for such an application I still seem to be wasted two conical roller bearings, I tried to use two ball bearings 6305 without shielding, so we can mount nilos for sealing and high performance grease lgem2+ep.as you can see we have a static coefficient of beyond 15 and a duration of 165000 hoursThat's more than enough.

This indicates that despite the ball bearing is not par excellence the most appropriate one to carry only axial load, if well sized it is able to carry all the load for a number of high cycles.

to say the truth, it would be possible to mount only one radial ball bearing since the back is already guided in the reducer and if radial forces are not born it is more than good to exploit the reducer as centering of the tree. so doing becomes even more compact.
Therefore, in itself, wishing to analyze the system of bearings of the initial exercise can be said that the use of two radial ball bearings and an axial bearing bracing is a system overflowing and mechanically more articulated, not in line with the economicity and functionality of the project.

 

[MassiVonWeizen]

as it looks at @domenico garofalo It does not affect much the discussion that opened, despite having visited it several times.
sorry for mechanicsmg that deep a thousand empty councils (it has made various assumptions starting from information deficits) and sorry because domenic, I use this philosophy, confirms that the majority of users, especially students, who knows maybe is the university system that teaches to treat others as servants... I don't know, he doesn't deserve the help he gets.

I would return to the old methods:
you, applicant, propose your solution and forum corrects you and helps.

?

 

[meccanicamg]

as it looks at @domenico garofalo It does not affect much the discussion that opened, despite having visited it several times.
sorry for mechanicsmg that deep a thousand empty councils (it has made various assumptions starting from information deficits) and sorry because domenic, I use this philosophy, confirms that the majority of users, especially students, who knows maybe is the university system that teaches to treat others as servants... I don't know, he doesn't deserve the help he gets.

I would return to the old methods:
you, applicant, propose your solution and forum corrects you and helps.

?

I was wondering what happened to the boy....there's a habit of asking the question....diving and maybe finally thank you.
Maybe he's still eating the panettone or he just needs a good education.

 

[PIETRO2002]

Maybe he broke up with some New Year's hit and sublimated!

 

[meccanicamg]

Maybe he broke up with some New Year's hit and sublimated! :

hahahahaha ????

 

[Domenico Garofalo]

Who asked you to answer and insert all these forms? ?
other thing, or you have pleasure in responding or better spending time differently, maybe along with your wives. in life you must not only receive, you must also give and you should be the old generations, the old engineers... great, great.

 

[volaff]

Congratulations on education.
not only did they answer you? !
You're a great rude!

 

[Domenico Garofalo]

Congratulations on education.
not only did they answer you? !
You're a great rude!

I firmly believe that those who exaggerated are them, then if you want to make them say "thank you" I'm content with them, but it seems exaggerated to do everything I'm messing up here for a thank you. are they who do not know the word respect and judge a boy without knowing him; That's all!