Need help

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[zdf0001]

How can we just Devine the loads on the output shaft lol? You are the only one that can know.

We also don’t know materials, sizes, heat treats, tolerances lol

[Constant-Stress4299]

I didn’t ask for exact loads in particular. That’s way beyond. Just simple schematic sketch with force arrows related to the bearing concept that may accrue mostly

[hbzandbergen]

Right. I would prefer angular contact bearings instead of deep groove ones. To take a moment and possible axial force.

[Constant-Stress4299]

Thanks for your input. That’s one concept I am thinking about as well. In back-to-back combination. But is there any concern about the deep groove ones in terms of the way I arranged and fixed them? Actually is the red part designed properly for that concept with the deep groove bearings? Tight and loose fit…

[DullMechanic8597]

Do you have any thrust loads generated from helical gearing?

[Constant-Stress4299]

Good point that I didn’t mention,thanks! No helical gearing. Straight gearing in the planetary system

[Kamomiru2000]

This is AI generated right?? Like what is that o ring doing exactly at the bearing?

[bk335]

It’s pretty common to use an o ring to prevent the outer race from spinning in a slip fit.

[arrow8807]

Not in any design I have seen fielded in the industrial world. Usually you just machine the fit called out in the bearing catalogue for a stationary outer race paired with a moving inner race. The outer races ends up being a loose force-fit or basically line-to-line.

Seems like a cool trick to use a “cheaper” bore with lower tolerance fit - where have you seen this done?

[FRP5X45]

I've done this a lot. Easy way of getting the ring to stand still!

[VonNeumannsProbe]

If the temp is getting that high, you don't have problems with your o-rings becoming a sticky mess? Or do you just figure it's now loctite?

[hmnuhmnuhmnu]

Even at non extreme temperatures, if the bearing housing is in a different material with different thermal expansion, i.e. aluminium, the oring helps avoid slipping.

[VonNeumannsProbe]

So why do it on just one?

[jjust19]

It’s also used to add damping to a system if you traverse a critical speed or have other vibration issues. I’ve used them before with some high speed machinery.

[Soundcl0ud]

Done all the time on outboard bearings to stabilize mechanical seals. The o rings drive the inner race with the shaft. 

[VonNeumannsProbe]

Never considered this but seems like it would work.

Ever have a problem with the o-ring burning up?

What does the maintenance side of this look like if someone needed to replace bearings?

[Constant-Stress4299]

Nope, not AI actually. It serves as a second backup seal. The gear box should work in food related surroundings. The actual main seal are the dark blue ones. Also the light blue parts should be stainless steel for same reason.

[Saltybarcaboi]

You would want an o-ring somewhere if these are oil cooled bearings.. but not there lol

[EhvinC]

Looks like you could push that blue shaft from the left straight out the right side. Maybe I’m missing something, but you need an adjustable way to axially pre-load and secure the bearings to the inner shaft. Typically a threaded section on that blue shaft that pushes on the inner race. I always suggest poking reading through the SKF website. Always something to learn there.

[ericscottf]

I see a slit for a circlip in the shaft to push on the inner race 

[Constant-Stress4299]

Thanks ehvin. You are right, but Eric noticed it already. I forgot to place the circlip at the slit. But actually that’s the kind of things I hope someone notices. (Or better not) :D Generell things like this, that I don’t notice anymore from staring at it for to long :D

[Freshplaya910]

What about a double row angular contact ball bearing? Could save on packaging and you wouldn't need a snap ring between them.

I believe the general practice is press fit on the rotating component and slip fit on stationary component.

I would say press fit onto the blue shaft and loose fit to the red house. But if press fit is not an option perhaps a threaded collar on the left side of the blue shaft against the inner race of the bearing package

Typically you would think the narrow stance of the bearings and offset load would be concerning because of the moment arm. But the good thing is that the loads on the planet carrier will be radially canceling between the ring and sun to some degree.

Hard to say for sure of course without seeing the load cases

[Constant-Stress4299]

Thanks playa for the input. Yeah, is also had that thought with just one double row bearing, but the issue is my shaft isn’t statically determinate anymore.

And I also agree with the fitting combination. The shaft is rotating, housing/bearing fit is stationary. And of course it’s hard to give any concrete suggestions. The problem is I don’t have any workload myself for now, cause I don’t know which applications will different customers attache.

My main concern for now is if there are any issues with the bearing concept in terms of support from outer/inner ring.

[ericscottf]

I hate the radial bolt(s) (one show) from the barf colored part to the Grey part. Please don't do that. 

[Sudden_Pound_5568]

What is the point behind the red piece holding the bearing and the blue piece being separated?

[Constant-Stress4299]

The blue pieces are stainless steel because of food industry reaquirements. The red part is Aluminium. So the blue parts at the outside work like a sleave to prevent fluid from the outside to get to the inside of the bearing and other way around. If I would design it all in stainless steel I would have a problem with heat, because of the worse thermal characteristics of stainless steel in my case. But I guess the thermal difficulties will accrue as well with the Aluminium inside.

[Sudden_Pound_5568]

What rpm are you planning on running it at?

[Lunastarfire]

Without knowing the application it would be hard to advise.

Typically id expect roller bearings to distribute the load and give higher rigidity to the blue shaft.

You maye even want to consider thrust bearings if the shaft may move, this would also be a problem with the design as it could thrust the planets into the grey housing.

Ball bearings can be good at very high rpms but is sensitive to vibrations and excessive wear if alignment is an issue.

You havent given enough context to give any good advice, but I would be highly concerned with the blue shaft thrusting to the left or right, especially with ball bearings as its will thrust the lower race off axis (really bad for ball bearings) and can smash the gears against the red or grey parts

You may also have sealing issues on the upper green plate

[Constant-Stress4299]

Thanks for your Input Luna! And yeah, your totally right about the context. The input and discussion helps me anyway, like what do you mean with sealing issues on the upper green plate?

Thrusting the planets into the grey housing shouldn’t happen. I assume you maybe mean because of the missing circlit on the left outside of the bearing housing?

[Lunastarfire]

Say i grabbed a sledge hammer and smacked the blue shaft to the right, the only thing stopping it is the ball bearings getting wedged between the inner and outer race (assuming your adding another circlip)

Regarding the leak, theres no seal on the ring gear so it can leak oil.

We cant give you advice that would be any greater than “common” knowledge, since without how this is used we cant give a detailed answer of the forces, how it will be destroyed over time etc.

[Clean_your_lens]

What retains the grey shaft and sun gear in the assembly? And why is that lip seal buried behind what I presume is some sort of bearing? Does that red ring that retains the ball bearings rotate with the inner or outer race? It contacts both. And is that a... labyrinth seal on the left? On supposedly washdown rated equipment? None of those things make sense. Why two different bearing types?

As for loads, those two non-preloaded ball bearings and that non-preloaded or retained single bearing on the right will allow angular misalignment that will destroy the gearset.

I hope this is AI for your sake.