The red one looks kinda DONE! It still drove on the trailer like that?Not only that but there's no telling how long it ran like that either!
Holy crap. Can you go chromolly?Ya,but defeats the purpose. The spider is there as a shock absorber.
Looking at data sheets now on 4 grades of nylatron. I'm concerned about melting point as I'm concerned temps were a factor in the spider failure as it is and nylatron and the PU spider have similar service temps. Looking at this stuff pretty strong though. http://www.cncplastics.com/PDFs/peek/Bearing%20Grade%20PEEK%20Standard.pdfNylatron Nylatron. Nylatron Nylatron Nylatron Nylatron Nylatron[/size]
Machine your own.
Is the coupling exposed(or can it be)during operation?Would be a cool spot for a vid camera?Or one of your thermal guns?Nope,enclosed. Thinking of adding windows though. The housing didn't get hot enough that you couldn't put your hand on it for a few seconds. That doesn't really say anything about how hot the spider ran at though.
What about delron. I know all of the trophy trucks are going to delron bushings. Not shure of the strength though.Unfortunately it has a fairly low melting point also.
I remember now-a Guido Coupling.
Yeah,it looks crumbled ,like rolling a pencil eraser between your fingers until it break apart?Yes, PU when crushed looks crumbled like that. I can't determine if that's the case here or not. Looking at it and feeling it it actually appears as if it has been chopped up instead of "rolled" like an eraser. I think the spider may have actually extruded out from the jaws under high oscilating loads like in the whoops and have possible "rolled " off the OD between the jaw and housing. There is only approx .080 clearance from jaw OD to housing ID that would have rolled off pieces similar to the eraser between the fingers example.If that is the case the slices could be explained due to the pinching action the curved jaws would have at their tips as the spider was disintegrating. If you look at the pics you can see the slices I'm speaking of.
I figured changing the size was not an option.Yes the casting of PEEK is an option but likely cost prohibitive. I WILL check it out though.Problem is that PEEK is not going to have any real shock absorbing qualities as it is nearly as hard as aluminum even in a PEEK composed of 10% moly ,10%teflon and 10%carbon fiber has a compressive strength of 13,000PSI. All other PEEKS are 20,000-25,000 PSI. All are to hard to give any shock absorption. That being the case aluminum would be far easier to machine and do the job. I'll give the guys a call though and pick their brains. Thanks for the link!
You could cast/mold the PEEK or have it casted.
These guys are the best people I have found for knowledge on plastics. I used a bunch when I worked on Space Station. They were super helpful. They have a machining guidline here http://www.boedeker.com/fabtip.htm (http://www.boedeker.com/fabtip.htm)
The bearing grade PEEK (Bearing Grade, Ketron HPV) shown here says "easy machining" http://www.boedeker.com/peek_p.htm (http://www.boedeker.com/peek_p.htm)Yes. I see this grade as being a better choice possibly but similar to the one you show. http://www.cncplastics.com/PDFs/peek/Bearing%20Grade%20PEEK%20Standard.pdf It has moly,teflon and carbon fiber at 10% each blended in. Also is a bit softer at only 13,000PSI compressive strength.
You want to ask for an Applications Engineer. That usually gets you past the sales weenies !ABSOLUTELY!!!!
Yes. I see this grade as being a better choice possibly but similar to the one you show. http://www.cncplastics.com/PDFs/peek/Bearing%20Grade%20PEEK%20Standard.pdf It has moly,teflon and carbon fiber at 10% each blended in. Also is a bit softer at only 13,000PSI compressive strength.
Maybe I spoke too soon. ;D ;D Pic 1 is of a good spider of the strongest (green 298 lb.ft. nominal/597 max)available polyurethane spider for the curved jaw lovejoy the VW091/busa adapter uses. Pic 2 is of what I used-or whats left of it anyway(red 298 lb.ft. nominal/479 max ) . The normal/maximum temperature for the red is 212F-248F. The green is slightly higher at 230F-266F. They are both rated for 7100 rpm . The busa at 10,500 rpm has a countershaft speed of6579 rpm so that is well within spec. Anyone think that at the current busa power level of approx 220 HP the green spider can survive? The red one sure as hell didn't! rofl thumb down thumb down eyes My other option is to make my own spider from some other material. I don't know if this was a capacity or temperature issue. Opinions are solicited!
There was really no evidence of it contacting the tube ID. The spider COULD have extruded enough though to allow the jaw tips to act like a pain of nipper jaws as the torque is applied and reapplied repeatedly and slowly eat away at the spider possibly. The factory lovejoy jaws have slightly radiused tips and the ones I'm using don't. A lot of possibilities . Gonna take some R&D to cure.
Dayum. Catostrophic failure..... ;DI see no sign of any rubbing anywhere. No sign of any melting anywhere.The PU either blew to pieces or was chewed up. I'm leaning towards a combination of both.This pic seems to show that evidence? ???
As tight as the clearance is between the jaws and the case not very large of parts could have gotten out. So if they grew out past the jaws then they would start burning on the case. Can't see that in the picture but can you see rubbing on the removed part of the tube? Probably not the way the outside of the jaws don't show anything rubbing. O course if it was gone on your first trip then corrosion may have hid the evidence since.
Whatever material you put back in, I suggest running it for a short time then pulling the cover and taking a look before the evidence is ground to powder. :o
I really think that the spider compressed enough to allow the jaw tips to contact,or near contact,each other and act like nippers on the spider tips. Slowly the tips were eaten away and as the spider was constantly being flung to the OD, the nipping away accelerated as the jaws were able to even more easily contact each other the more spider was lost/nipped away. I think it kind of fed on itself. I'll radius the jaw tips more like the OEM jaws are to hopefully stop that and test out the green spider. I think that it may cure the issue at current power but still need to explore other options as I doubt it will hold up to 300-400 HP.
I thought that with the shape of the jaws it would almost want to squeeze the material into the center instead of to the outside. With the centrifigal force added it would have been about equal. obviousely something went wrong.
It seemed like the green was quite a bit tougher even if the specs don't seem to show it.
ETA: Actually machining a spider may be much better by getting rid of the 3-D present in the factory spiders. The curve that allows for more angular misalignment greatly reduces the contact area and centralizes the loading. There is virtually no chance of angular misalignment in your setup, so the added contact area of a machined 2-D spider will have more consistent loading and less peak pressure in the spider material.
I remember now-a Guido Coupling. http://cgi.ebay.com.au/BMW-drive-shaft-UNI-GUIBO-COUPLING-E46-E12-E28-E34-E23-/110590056947 (http://cgi.ebay.com.au/BMW-drive-shaft-UNI-GUIBO-COUPLING-E46-E12-E28-E34-E23-/110590056947) Funny thing is that they aren't rated as high a torque capacity as the LJ coupling I'm using. Looked into them early on.
Where did you find the torque ratings. A 760 uses them and weighs 5026 empty with 550FTLB's of torque. With a first gear of 4.71-1 they should be good for at least 2600FLTB's of torque.............
Even the lowly 3 series with 200FTLB's and a 4.32-1 should be good for 900..........
Are you SURE the ratios stated are first gear? Aren't they rear end ratios?
Where did you find the torque ratings. A 760 uses them and weighs 5026 empty with 550FTLB's of torque. With a first gear of 4.71-1 they should be good for at least 2600FLTB's of torque.............
Even the lowly 3 series with 200FTLB's and a 4.32-1 should be good for 900..........
Are you SURE the ratios stated are first gear? Aren't they rear end ratios?
Had an engineer suggest using titanium for the spider.
I'm gonna say between the torque and the RPM the small inner circle that holds the spider together gave way. Allowing each individual part to slide its way towards outside ending up like a pile of eraser shavings, which prob didn't take too long. A tougher material +, easing edges +, little more material in center to hold together +.PRICELESS!!!!!!!! I did too! rofl rofl rofl rofl rofl rofl
I didn't finish engineering school, but I did stay in a Holiday Inn on way to LS. ;D
I learn so much from this site. Before today I had always thought this was a "Guido Coupling."Holy crap :o the things you see when you don't have a gun!! ;D
Go figure.....
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Are you suggesting that you use this type?Not suggesting anything but that revshift giubo is the performance upgrade to the 3 series BMW one suggested by BDKW1. Uses 10MM pins. Must work fine as the pins are not reported by the bimmer world to have any issues at all .The stock giubo does have issues with the rubber going bad as all rubber will eventually.Consider what really drives a u-joint. 2 little nubs in a small diameter package can handle upwards of 2000 HP in a drag car.
The diameter of the 3 driven pins on that with the package size constraint you're working with is going to be a problem. If you "fit" that concept into the area you're working with the pins are only going to be about .375 dia? Not enough for the load you're trying to put thru it. You could fit a paddle shape like is on the Busa motorcycle alot easier but I still doubt it would carry the load considering the reduced diameter you're trying to fit it into.
I think Carl has a good thought with the wimpy little ring in the middle on your current part failing and then the pads floating around and getting squished out into the grinder :)
U-joints...... Two little nibs that are loaded in almost perfect shear and fully supported by the bearing surrounding them. The problem with this is the flexible coupling allows the pins to be in bending unlike the u-joint.There is no giubo on a busa. A cushion drive,yes, but not a giubo.
Basically I'm just comparing the factory Giubo on the Busa with the envelope you have to work in. The diameter is the key.
There is no gudio on a busa. A cushion drive,yes, but not a guido.
Polar moment of inertia will be lower.Damn if I know. LOL!!! His reasoning was that titanium was a shock absorbing material in itself . Sort of like why titanium is used for things like golf clubs. I countered with it would be abrasive on the hardened steel jaws. His answer was "hmmmmm.........". ;D ;D
Check out this giubo. ;D ;D
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A golf club is different in that the shaft bends over the entire length. I doubt it would compress any significant amount in this application.compression not necessary to any degree if it absorbs shock. Ever used a titanium hammer? Guarantee you the head absorbs a significant amount of the head hitting a nail shock. You can feel the difference easily. Not saying I'm considering it at this time but it makes sense.
You could make a similar setup with any polyurethane bushing. Making your own, you could optimize the size better. With each bushing fully encapsulated, I think they will hold up better than the star shaped thing.I'm not convinced one way or the other to be honest.
I have a plan. I have stuff in hand. ;D I'll let you know results soon. ;D ;D Probably take a couple weeks .
the spider is already poly
I have a plan. I have stuff in hand. ;D I'll let you know results soon. ;D ;D Probably take a couple weeks .
Welllll................. it worked for him! LOL!!!!!!
Need to get over your way sometime to see that beast run..You WON'T be disappointed.
SO Fabrs input shaft is broken........ roflAnd a popsicle stick?
Duct tape!!!!!
Even with a 300M shaft, something else down the line will go next.That's how improvements are made my friend.Who is TCS?
If you have drawings for it, call TCS. They make shafts for a lot of people....... Rusty is good people.
Who is TCS?www.tcsperformance.com/ (http://www.tcsperformance.com/)