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YOUR RESEARCHengineering: thrust load on IMSB
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Recommend retrofit or solution over the roller bearing
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Suggestion
Yes I am aware and if you look hard enough you'll find that even LN still recommend a retrofit or solution over the roller bearing.
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Suggestion · Original poster
I'll try to set aside some time to cruise youtube...
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Suggestion
An I am surprised why you can't use google and the Rennlist search function.
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I'm trying to decide between the LNE Retrofit (ceramic ball bearings) and the RND roller bearing for my IMSB replacement.
I've done some reading about both...my main question is: why would there be much axial (thrust) load in this application?
Thanks.
Yes I am aware and if you look hard enough you'll find that even LN still recommend a retrofit or solution over the roller bearing.
But hey it's your car - install whatever you'd like.
I've read that page, and I don't think it answers my question: in this particular application, why would axial load be a concern? How would axial load be applied?
From this non-engineer's perspective, radial load capacity is really all that should matter.
When you say "particular application", are you asking the forum why it's necessary that a bearing inside the intermediate shaft of a Porsche M96 engine needs axial thrust control?
If so, the intermediate shaft is like an airplane's propeller, when the engine engages and shaft is under load, there is axial thrust. That thrust on the shaft could damage a cylindrical type bearing.
I hope I am remembering this correctly. The other end of the IMS has a plain bearing with no thrust control at all. So all of the thrust load is handled by the IMSB at "this" end of the IMS. I can't say I know where the load comes from, it is probably not a large load, but it exists. Probably any spinning shafts has some thrust load, even if it isn't for some explicit purpose. So it is important for the IMSB bearing to handle it. It is getting hard to find the reference (source) for this point, but it is here somewhere on the forum.
Beyond taking a class in mechanical engineering, one of the quickest sources of information is by going to YouTube and searching "axial load engines". There are many videos that describe and demonstrate axial load/thrust.
I can understand axial load in this particular example (airplane prop), because the prop is pulling the plane forward. But, in the case of the IMS, that factor doesn't exist.
I'll try to set aside some time to cruise youtube...
You are always going to get some axial thrust loads......the shaft is not going to be perfectly balanced in the axial direction, it has multiple chains on it.....each is going to have a thrust component pushing or pulling on it. In my opinion it's going to be less axial thrust load as compared to radial thrust load, but it's there. This is not rocket science. It has to be transferred (absorbed) to a stationary component (the block) by some means.
Understood. But, what is the magnitude of these forces? Are they large enough to eliminate roller bearings (and their reduced axial load capacities) from consideration?
Again, I'm not an engineer, but the forces you mention here would seem to be minor.
If you want to calculate the forces, then I suggest you take the engine apart and start looking at it and figuring out how it works. Do you know the size of the IMS bearing? It's about the size of a nickel....maybe a quarter. So in absolute forces, it's small.
In my opinion there is minimal thrust load on the IMS. I think people have way overblown the thrust issue. There are no helical cut gears riding on the IMS and the chains are at 90 degree3 angles. If the chains were somehow missaligned to say 89 or 91 degrees, it would exert some thrust load. But other than that, there is a small amount of thrust from the oil pressure bleeding past the oil pump gears on the nose of the IMS making a light thrust. The only other thrust is the weight of the IMS when g-force is exerted from accelerating or decelerating creating thrust. This is a minimum amount of thrust/axial load.
This is a source reference. Confirm exact model applicability in the original material.
