dirtydiesel Posted September 21, 2013 Share Posted September 21, 2013 For a number years now I've had an idea for a variation on the 1 link setup. I sounded the idea out with Bill a couple of years ago and since then I think I've hammered the idea into a workable solution. The problem behind the idea is that any suspension system based around a panhard rod can "lock up" in certain circumstances as one wheel is forced to travel in an arc around the other wheel instead of an arc around the roll center of the suspension. My "idea" was to replace the panhard rod with an A frame, but in order to allow the axle to move in an arc the axle end of the A frame needs to be telescopic, so I came up with the idea of a "sliding A frame" now I'm not sure if this is a totally original idea of mine or something I've plagiarized. This weekend I found a suitable test bed for the idea, our Suzuki jimny based trialer, it has had a 1 link and panhard setup on the front for about 3 years, but until now we hadn't found time to do the back end. Pics to follow. Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 21, 2013 Author Share Posted September 21, 2013 Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 21, 2013 Author Share Posted September 21, 2013 The bearing is a 35mm housed small footprint, I have tapped the mounting bolt out from m12 to m16 and by mounting it at 45° the mounting studs shouldn't really see any shear loadings. The bar that slides through the bearing is 303 grade stainless turned 0.1 under for a nice slide fit. The chassis ends of the sliding a frame are range rover trailing arm bushes The 1 link bush is a 3" ballistic fabrication joint. Quote Link to comment Share on other sites More sharing options...
simonr Posted September 21, 2013 Share Posted September 21, 2013 Interesting idea Dan. By limiting the travel on the slide, you can limit the droop without affecting articulation - which is a plus! Good thinking - I like it! Si Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 22, 2013 Author Share Posted September 22, 2013 Thanks Si, I thought about having a stop on the slide I thought it might further shorten the life of the bearing though, I will though be running a center check strap as I don't like descending hills with lots of rear droop! Quote Link to comment Share on other sites More sharing options...
Anderzander Posted September 22, 2013 Share Posted September 22, 2013 That's the bit I can't quite get clear in my mind. With it being a fixed bearing (rather than a rose joint) it seems it will resist the rising and falling in the axle where the travel radiating from the A frame and sliding joint pivots / axis are divergent ? Unless they pivot on a common axis. I doubt I've explained that clearly ... But I mean in the same way that a motorbikes swinging arm pivot differs from the gearbox sprocket creates varying tension in the chain (but of course the chain can flex in a way the the sliding joint can't). Quote Link to comment Share on other sites More sharing options...
Anderzander Posted September 22, 2013 Share Posted September 22, 2013 Should add - it looks beautiful! Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted September 22, 2013 Share Posted September 22, 2013 That's the bit I can't quite get clear in my mind.With it being a fixed bearing (rather than a rose joint) it seems it will resist the rising and falling in the axle where the travel radiating from the A frame and sliding joint pivots / axis are divergent ? Unless they pivot on a common axis. I doubt I've explained that clearly ... But I mean in the same way that a motorbikes swinging arm pivot differs from the gearbox sprocket creates varying tension in the chain (but of course the chain can flex in a way the the sliding joint can't). The bearing isn't fixed, it is a self aligning unit. I think with the combination of the sliding shaft and self aligning bearing unit on the axle, it will self adjust to the conflicting arcs scribed by the lower and upper wishbones . I mocked up a similar arrangement some time back, but used an old unservicable hydraulic ram as the sliding joint, attached to the axle with a range rover rear trailing arm axle bushing. Dan, This morning I found a bloke on Pirate who fitted offset one links front and rear in an attempt to cancel torque roll, and from his positive reports, the theory appears sound. His reply is on the One Link thread currently halfway down page one on General Tech forum. Quote Link to comment Share on other sites More sharing options...
Anderzander Posted September 22, 2013 Share Posted September 22, 2013 The bearing isn't fixed, it is a self aligning unit.. Ahhh ! I can see that now in the photos. A bigger screen and being more awake made the difference. Quote Link to comment Share on other sites More sharing options...
elbekko Posted September 22, 2013 Share Posted September 22, 2013 Interesting. How will you keep the grime out of that sliding bit? Seems like it'd wear ridiculously quickly if it got some sand or something in it. Maybe a seal like there is on a propshaft? Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 22, 2013 Author Share Posted September 22, 2013 Interesting. How will you keep the grime out of that sliding bit? Seems like it'd wear ridiculously quickly if it got some sand or something in it. Maybe a seal like there is on a propshaft? I don't think the stainless bar would wear at all, the bearing insert might but the inserts themselves are about £8 and easily changed. I think the housing will wear out first, as the self aligning function is not really supposed to be in constant motion. Next I have to decide what to spring it with, whether to use air shocks, or I have some short coilovers that I could cantilever. Quote Link to comment Share on other sites More sharing options...
Landy-Novice Posted September 22, 2013 Share Posted September 22, 2013 that will create quite a bit of heat wont it? if its worked hard? Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted September 22, 2013 Share Posted September 22, 2013 that will create quite a bit of heat wont it? if its worked hard? It's only purpose is to locate the axle laterally, so when not cornering or driving on side slopes there is hardly any loading on the shaft and bearing to create heat. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 22, 2013 Share Posted September 22, 2013 Next I have to decide what to spring it with, whether to use air shocks, or I have some short coilovers that I could cantilever. I assume you just mean for suspending the vehicle, and not to control that upper link in any way? Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 22, 2013 Author Share Posted September 22, 2013 I assume you just mean for suspending the vehicle, and not to control that upper link in any way? The upper link is finished at that. I halfway fancy making a cantilever setup to make use of some small coilovers I have to suspend the vehicle. Quote Link to comment Share on other sites More sharing options...
Daan Posted September 22, 2013 Share Posted September 22, 2013 Dan, is there any reason to choose this setup vs. a watts linkage? or is it just packaging? Daan Quote Link to comment Share on other sites More sharing options...
simonr Posted September 22, 2013 Share Posted September 22, 2013 Interesting.How will you keep the grime out of that sliding bit? Seems like it'd wear ridiculously quickly if it got some sand or something in it. Maybe a seal like there is on a propshaft? I think if I were making such a thing, I'd make my own spherical joint with a Phosphor Bronze ball. If the clearance is only a couple of thou, there isn't enough space for dirt to get in, but the Phosphor Bronze is self lubricating to a large extent and will outlast a bearing. The next OTT step would be to fit single lip seals on either side of the ball around the shaft - you could even use a corrugated seal which will flex enough to allow the ball to swivel. You could even cast your own out of PU? If you happened to know someone with a 3D Printer - you could get them to print the positive for the corrugated seal / bellows, make a mould in Silicone then cast the PU in that. Si Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted September 22, 2013 Share Posted September 22, 2013 I think if I were making such a thing, I'd make my own spherical joint with a Phosphor Bronze ball. If the clearance is only a couple of thou, there isn't enough space for dirt to get in, but the Phosphor Bronze is self lubricating to a large extent and will outlast a bearing.The next OTT step would be to fit single lip seals on either side of the ball around the shaft - you could even use a corrugated seal which will flex enough to allow the ball to swivel. You could even cast your own out of PU? If you happened to know someone with a 3D Printer - you could get them to print the positive for the corrugated seal / bellows, make a mould in Silicone then cast the PU in that. Si Threads another couple of worms on the hook and throws it back out there. What is wrong with using a greased up 10 ton Porta Power ram with a trailing arm bushing on the end of the 'pushrod', and a rack and pinion or shocker bellows to keep the crud away from the exposed shaft ? Used rams can be had for 20 bucks or even free. there is an external thread on the cylinder to which a bronze bushing carrier could be screwed on to cope with side loadings if we really want to get sophisticated. Most of us could do all that at home without a lathe and just a welder. Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 24, 2013 Author Share Posted September 24, 2013 Dan, is there any reason to choose this setup vs. a watts linkage? or is it just packaging?Daan A watts linkage in its conventional layout would be far to vunerable to damage i think. I had considered running a watts linkage in a horizontal plane above the axle, but the linkage and arms would most likely want to live where coilovers should, Plus i really wanted to see how this works out, my next trial is about a month away, but i might try a p&p before then. Quote Link to comment Share on other sites More sharing options...
simonr Posted September 24, 2013 Share Posted September 24, 2013 Threads another couple of worms on the hook and throws it back out there. What is wrong with using a greased up 10 ton Porta Power ram with a trailing arm bushing on the end of the 'pushrod', and a rack and pinion or shocker bellows to keep the crud away from the exposed shaft ? Used rams can be had for 20 bucks or even free. there is an external thread on the cylinder to which a bronze bushing carrier could be screwed on to cope with side loadings if we really want to get sophisticated. Most of us could do all that at home without a lathe and just a welder. A ram is a fine, simple idea - but it's not how Diesel has made it! My way at least retains most of the original fabrication. Rack & Pinion gaiter is a great idea. Si Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 24, 2013 Author Share Posted September 24, 2013 A ram is a fine, simple idea - but it's not how Diesel has made it! My way at least retains most of the original fabrication.Rack & Pinion gaiter is a great idea. Si I don't think there would be any need to make a phosphor bronze Ball Si, the joint actually only needs to rotate in one plane and slide in another. I have a mk2 version all planned out in my head if this works as well as i hope, Here should be a short (amazing quality) video clip showing how free the suspension movement is. A round of applause is mandatory for my glamourous assistant Matt Quote Link to comment Share on other sites More sharing options...
deep Posted September 24, 2013 Share Posted September 24, 2013 "This video is private"? Sorry, can't watch it! Quote Link to comment Share on other sites More sharing options...
dirtydiesel Posted September 24, 2013 Author Share Posted September 24, 2013 "This video is private"? Sorry, can't watch it! Fixed i hope?? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted September 24, 2013 Share Posted September 24, 2013 Yup, looks good Dan Quote Link to comment Share on other sites More sharing options...
discomikey Posted September 26, 2013 Share Posted September 26, 2013 Dan, very O/T, can i ask what make that stainless toolchest is? p.s. very nice indeed, i do agree however, the use of a hydraulic ram could make any future "copies" of this work well, as rams are designed to work in dirty gritty environments and has the motions needed along with replacables. with the added benefit of the use of such ram as a helper in the bump situations, allowing softer springs for increased flexibility for ground contact. Quote Link to comment Share on other sites More sharing options...
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