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KYB Floating Fork Piston
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Posted by: MACE---------------------
Looking for trouble on the patent search page, I found a recent KYB patent on a floating piston fork design.
http://l2.espacenet.com/espacenet/b...+++6234505B1+I+
It appears that they are trying to pressurize the oil chamber using the fork spring on top of a floating piston that is concentric on the damping rod. One side effect of this is that the spring will move faster than the male slider because the spring seat (floating piston) is raised by oil displaced by damper rod.
I'm still trying to figure out if this is another speed sensitive spring scheme due to some calibrated bleeds... 
Posted by: Jeff Howe---------------------
I said something not so nice, I had to take it back. But you know, it was along the lines of rubber gimmicks in forks. Whatever happened to Disneys Dean Jones and his science experiments? Cannot Ross come up with an elastomer damping medium to put in the cartridge? Like Bib Mouse inserts or something? No oil? Surely he could tear down that segment of the industry. Imagine never having to change your fork oil. What bliss that would be huh? And no cavatation, no aeration, no bottoming....no springs? Without the oil he could go back to his original open cell elastomeric bumper material thats better then closed cell rubber pencil erasers and the bumper system would finally be golden...finally. Shall I continue? I'm having fun.... sort of. Until they create a gas charged, sealed, self adjusting, replaceable cartridge( with bladders OF COURSE) like a strut we will never be there. Foam, thats it. I really think Dean Jones could solve this problem for the world though. "Hey honey, I'm going to go out in the shop and swap out the MDHP (mid density high progressive) fork cartridge Bib mouses for the LOC (linear open cell) MX replacements so I can hit the track this weekend."
News flash>>>>> brought to you by some of the sharpest minds in the sand...
"Now available from Walker Evans Racing Shocks, the NEW shock technology utilizing 16th century technology today consisting of a fixed tapered needle within the shaft providing for unlimited tuning possiblity by replacing the needle with a different tapered version PLUS never exposing the shock to air?? Oops, I got off topic, we were talking bikes and forks here right...KYB in general. and yeah, imagine no hydrualic lock EVER!! There is a perfect lost hidden society out there someplace. Somebody besides Kevin Cameron must know the dang answers. I have not been smoking pot. The answer is truly in speed sensitive air spring and bib mouse cartridge inserts. Remember, you saw it here first.
Posted by: drehwurm---------------------
Servus Mace,
Yeah, very interesting and simple. I don't think the "speed sensitive" part is the main motivation here, but to have two sperated chambers like on a rear shock (floating piston on Öhlins and WP PDS shocks). A few questions do arise though:
.) Does there need to be a little oil in the upper chamber, to keep things lubed?
.) How to bleed the lower chamber - possibly from the bottom! Bleed screw on the bottom tap.
.) If the upper chamber is pressurized (like on a shock), what about the seals and stiction?
Movement of the floating piston seems to be too little to have much effect on the springs, but on the other hand might be sufficient to compensate for the loss of the bottoming cones (oil locks).
Just a few ideas.
Michael
Posted by: Jeremy Wilkey---------------------
Mace,
Ask and you shall recieve.. Thankyou for this tasty fritter. This really fits into some things I've seen on Vulimens bike back in SX, and some conversations I've had with Mr.Maeda. The KYB engineers have been brain storming over ways to overcome Showa's patent on the Twin Chamber design, and ultimaltey to one up it. I can't veiw the imagines, as I belive that they are not compatiable with the slow net-work here at the tech.. I will try from home and my Cable IN.
With a big cartridge, you could have a very "small floater" which mean a big sweep in movement..
I'll be in touch on this one.
BR,
Jer
Posted by: Jeff Howe---------------------
Geez...I try to throw out a little of the old Mace humor to get him going and I get ignored...figures I guess. That patent was approved in 1999, so makes ya wonder don't it. I've long been waiting for a KYB shot at that Showa TC. A glimpse of the future was established by Showa in 94, and it's been awhile in coming for KYB.
Posted by: Jeremy Wilkey---------------------
Shocknut,
You did'nt get ignored... I was still trying to plum exactley what you where saying.. I'm sure coments are comming soon.
BR,
Jer
Posted by: Jeff Howe---------------------
It was all a joke type thing. I was stuffing bib mouse inserts into the cartridge dude. Instead of oil. Dean Jones is an old Disney movie star. Maybe Mace will know, he's old like me I think. Maybe I do need to smoke some pot? 
Posted by: marcusgunby---------------------
Jeff i read your post and didnt get one sentance-thought it was wrote by Jer
jer only kidding i usually understand you after i re-read it a few hundred times
Posted by: Rcannon---------------------
Shocknut, where the hell do I find enough flubber to fill my forks????
Seriously, in the "new" forks there is a rubber anti-bottoming thing in them. Is this what you would like to see gone? Why???
Posted by: Jeff Howe---------------------
LOL...Ok so I threw up on my keyboard. I maybe need to get some sleep. It was nothing to do with Mace's post. I seen Mace was there and well...I remembered how the guy used to make us laugh, and I just started letting weird thoughts go through my overused brain. Ok, forget it. I was using foam as a damping medium. Showa created a good fork design back in the mid 90's. KYB has been throwing gimmicks in theirs for years now. I was making fun of all the gimmickry crap compared to what the Showa is. The KYB is a good fork don't get me wrong. I was making fun of the bumpers, the bladders and the Walker Evans thing is a snowmobile shock that is using a fixed needle in the shaft and claiming it 30th century technology. I apologize to Ross for making fun of his gimmicks, but the Walker shock is BS.
Posted by: marcusgunby---------------------
Im amazed we havnt had more different type of forks-we have the twin chamber/kybs and early showas which are similar-wps and ohlins are not much different from KYBs and early showas-the only interesting stuff was mazzos and Wp50s and they havnt really moved forward.
Posted by: Jeremy Wilkey---------------------
Quote:
Originally posted by marcusgunby
the only interesting stuff was mazzos and Wp50s and they havnt really moved forward.
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:scream: :scream: :scream:
Well how do you define intresting.. Somebody needs to invite Kelvin Thomas on the board.. Intresting...very....effective... No..
SNUT.. you mean a replaceable needle jet is not state of the ART?
As for the KYBs.. The CV is not a gimic, the elastomer is not a gimic.. And the bladder is not a gimic.. Now they may have advantages and disadavantages, yet they do serve real purposes, and more than that KYB is actually doing something.. The Showa stuff was devloped ten years ago.. Its not changed much since. KYB is at least doing something..
BR,
Jer
And by that argument here's to Marzo....
Posted by: Jeff Howe---------------------
LOL. So whats wrong with raising a fews hairs and eyebrows? Not a needle jet dude, a needle! They change the needle to one with different taper. You call that new wave? You can pretty much accomplish the same thing with a adjustable rebound like we have now the way I figure it. But Showa just went to 34mm cartridge didn't they?
Posted by: MACE---------------------
Quote:
Originally posted by Shocknut
It was all a joke type thing. I was stuffing bib mouse inserts into the cartridge dude. Instead of oil. Dean Jones is an old Disney movie star.
|
For cryin' out loud, Fred MacMurray invented flubber. :flame:
And please don't mention Robin Williams. 2x :flame:
Aren't the mountain bike gadflies just now abandoning flubber and moving on to decarbon forks?
Quote:
Originally posted by Shocknut
Maybe Mace will know, he's old like me I think.
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Oops, I think I'm busted....
Posted by: Rcannon---------------------
Mace, I strongly objet to your saying Fred McMurray invented flubber. How could he have? He was busy taking care of Ernie and Chip. I swear, Dean Jones invented flubber....Unless Dean Jones was the "Herbie the Love Bug guy". Then, your exactly right.
Do you ever watch those old shows? Then folks wonder why they all had substance abuse problems.
Posted by: marcusgunby---------------------
Jer i want radical-no spring , rotary damper acting on both legs type of forks
Posted by: Papakeith---------------------
It was Fred McMurray in the movie "The Absent Minded Professor" cir. 1961
Posted by: WoodsRider---------------------
Quote:
Originally posted by Papakeith
It was Fred McMurray in the movie "The Absent Minded Professor" cir. 1961
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And you complain that you never add anything of value to these threads.
Posted by: Papakeith---------------------
Ok, of value pertaining to suspension.:confused:
Posted by: DEANSFASTWAY---------------------
Whats up with the Husky twin chambers ?
Posted by: drehwurm---------------------
Servus,
After reading the other 7 pages (sic!) I'm pretty sure the 2003 48mm WP forks would be a good base to try this modification. A look at
http://members.eunet.at/mpetkov/WP48.jpg
shows that the oil locks (bottoming cones) would be a good guide for the piston and a little math reveals that the travel at 300mm of fork movement would be 46,6mm - no problem as the oil locks have a length of 70mm. So all I need is the following:
.) polish the outside of the oil locks and the inside of the inner fork tubes (only where the piston travels)
.) make a piston; should be straight forward on my lathe
.) find a 44mm (OD) and 26mm (ID) bushing - any ideas?
The WPs don't use a cylinder valve (or seal valve #25 in the drawing), but apart from making the whole setup less effective I don't see a problem here. Another point is, that I can't use a blow-off hole (#24) to keep the pistons from traveling to far. Once the oil locks come into effect the pressure inside the cone will be too high to allow for the blow-off. Instead I'll try to machine vertical grooves into the piston guide surface on the oil locks to allow for a "blow by" instead of a "blow-off". A tiny hole in the piston for bleeding purposes will also be necessary.
I think that this modification can be achieved without changing any vital parameters like spring preload or oil height, so that the effects will be clearly visible. Only point I'm not sure about is, if the "oil-loss" out of the sealed chamber during the compression stroke can be replenished fast enough without using a check valve on the piston. This can be quite easily accomplished though and would probably be way easier than fitting a check seal to the WPs.
Any ideas where I could scavange the bushings (piston bands) or why this shouldn't work?
Michael
Posted by: Jeremy Wilkey---------------------
Michael,
We could simply make bearing out of garfil tape. (just like shock piston ring) and they would seal if made right. Also I can custome make some shims, for a check valve circuit. I really think we could make this easy. We just hold the shim in place with a snap ring.
BR,
Jer
Posted by: Jeremy Wilkey---------------------
Dean,
I belive they are so insignificant Showa won't sue them kind of like KTM twin chammbers.. But it allso could have something to do with international patent law.
BR,
Jer
Posted by: marcusgunby---------------------
It could be like KTM/Husky running the front brake hose like CRs do.However a Husky twinchamber is no advance as its a copy of the showa-i want a new invention.
Posted by: Jeremy Wilkey---------------------
Guys here is the first step in a beta version. I will add a check valve cicuit tommrow. The fittment is about perfrct, Its going to be a little sticky for a few minets of riding, beacuse both bands will need to size, but its not stiff, just sticky.. Piston ringsw tend to lose a .001 to .002 as they "break in" The seal seal should be about right.
I usesd a 44m by 10mm Piston Ring from a KYB 44mm piston and the internal band seal is custom..
I ran the numbers and the Rate should be increased by about 2% at a speed above the bleed threshold.
Fun stuff.. Will show more as it comes together..
BR,
Jer
Posted by: Jeremy Wilkey---------------------
This is the back veiw
Posted by: Jeremy Wilkey---------------------
I sliped it on a 02 fork just for demostration purposes...
Posted by: Shawn Mc---------------------
It seems to me that you would want to be able to adjust the bleed off in the locking chamber, do be able dial in or out the 'harshness' of the bottoming action. If your bleed off isn't quick enough, wouldn't it feel just like metal to metal contact? And if its too quick, wouldn't you get actual metal to metal contact?
I am a rube, but I find this fascinating
Posted by: marcusgunby---------------------
Sorry for my stupidity but who do i send my money to to convert my KYBs?it sould alot cheaper than buying some TCs off a 250.I have the money waiting for a system that works.
Posted by: prcucuma---------------------
Wouldn't the stock shims setup be quite to hard compared to a stock fork? Because the force to move the oil out of the cartridge into the chamber under the new floating piston will be greater (the spring tries to keep it back?!?)? And what about the sealing between the cartridge rod and the cartidge. As it is stock there is only a DU-bush (WP) so there will be a leakage...under heavy compression some oil might flow out of here instead of going through the compression valve.
Drehwurm: You asked if you will need oil on top of the floating piston-unless you want to disable the hydrostop and feel a metallic hit when you bottom your forks you should put some in;-)
Posted by: prcucuma---------------------
Hi Jer,
wouldn't there a better sealing if you had used some o-rings? On the 43mm WP forks it could happen that you mounted the cartidge slightly out of line (not concentric to the OD of the outer tube) so if you have a case like this the floating piston will stick and not move free. Maybe this is no problem at the 48mm WP forks but I just wanted to remind you that there might be trouble...never mind.
Great to see someone trying something immediately after seeing it. Carry on!
Posted by: drehwurm---------------------
Servus,
Jer: This exactely what I had in mind. A piston band from an Öhlins PDS reservoir piston and a WP fork rebound piston should work with little modification. How do you intend to bleed the forks or install the piston? My idea would be to do all the bleeding and oil level setting, then install the piston. A tool which would keep the check valve on the piston open, would make for an easy installation.
prcucuma: The original design uses no hydraulic bottoming device like the WP does. Still a good point :confused:
Michael
Posted by: marcusgunby---------------------
Well i considered myself fairly up on suspension stuff but this is deep-to all new readers dont expect to understand this stuff straight away-or maybe everi think i need to get some tcs apart and have a good poke around.
Posted by: Jeremy Wilkey---------------------
My only purpose in doing this to learn, plus I have a certain someone I intend to send some love letters to...... ITs not who you think... But MR. Green desreves an eye opener...
Posted by: prcucuma---------------------
Hi Jer and drehwurm,
did you try this little mod under riding conditions? It would be interesting to know how it affects the action of the fork...
Posted by: Jeremy Wilkey---------------------
Guys I had faimly in town all weekend, and did not get much done of use on a professional level. However I did manage to reinact Fight club with my brothers (nothing quite like the 6 Wilkey brothers when we get midevil), visit my realatives graves, continue working on my Great Great grandfathers, burial site, etc.
I did exchange some e-mails with Ross Maeda on the topic, and I got helpful pointers. The beta version still may work, but I'll have to do some serious machining. I will get back to you on this. From the sound sof it, its going to be more a learning tool, than much of a performance gain, well just have to wait and see.
BR,
Jer
Posted by: drehwurm---------------------
Servus,
I have all the necessary parts on order, but my piston design will be different from Jer's, because of the way I plan to incorporate the check valve. Nevertheless it is vacation time for me now and things will have to wait till I'm back.
There are two reasons why I'm pursuing this concept. First it looks mechanically very simple to realize and second I think it has potential in improving fork action without any losses. Why? I did my first shock not too long ago and naturally tried a lot of things you are not supposed to when doing a service. One of those was to try different amouts of pressure in the reservoir (Öhlins shock, no bladder, floating piston!!!)) - ever did this? If there is no pressure the shock will always sound like it is not properly bled, no matter what you do. Just put in a little pressure and the "blubbery" sound disappears. A shock without pressure on the oil chamber doesn't work well - a fork without pressure works fairly well - so a fork with a pressurized oil chamber should work BETTER, at least more consistent. Does this sound logical?
Michael
Posted by: marcusgunby---------------------
I adgree.It does sound logical.
Posted by: HONDA65---------------------
I'm coming in late to this post, so bear with me. In reading through this, I'm I understanding you guys in that your talking about converting a KYB to a twin chamber? I looked at the patent picture, but I couldn't pull up Jeremy's picts. Aren't the factory KYB's (at least on the Kawi's) already using this sort of a setup, with high/low adjustments? Exteremally, they sure look like Showa T/Cs.
Posted by: chrismxer---------------------
Anybody know if this went anywhere? Ride report? Anything?
Posted by: drehwurm---------------------
Servus,
I never got close to anything "testable". Still like the idea though.
Michael
Posted by: Jeremy Wilkey---------------------
Ohlins is using a similar idea for their new TC fork BTW..
Posted by: chrismxer---------------------
Did you ever get anywhere with this jer? Looked like you had something goin.??
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