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Cross Link Suspension - It's New - Comments and discussion invited

Wicked Al

Well-Known Member
Why do you need the green and blue fluids? It seems redundant. Is it because of the valving? Enjoying following along and learning.
Here is a graphic of one corner under compression and what that does. The blue and green are nothing more than the mechanical links, they sit on either side of the rams. As the shock is compressed that displaces one ram into the cylinder, that transfers the force over to the other cylinder and displaces that ram the same amount. The top of both of the connected shocks act in unison. When the fluid is displaced, it has valving it goes through that is for both tops of the shocks, compression and rebound. In this case, as the tire rolls over the rock, the brown, regular individual shock, compresses. Because the ram above it has to compress two springs, the bottom portion compresses 2 inches for every one inch of the top. Because it is connected diagonally, the rear passenger tire is being lifted up an inch, which in reality means that corner is dropping down an inch. That acts the same as a diagonal sway bar. Back to the rock you're going over. In a conventional system, when the front tire rolls over the rock and the shock compresses, it is lifting the vehicle up. It's like a long plank with a weight in the middle and you're lifting one end of it. With the Cross Link, as you start to lift the front, the back end is dropping down. Now it's like you have a long plank with weight on it, but there is a pivot point in the middle like a teeter totter. This means your center of mass is moving less to go over the same obstacle. Not only does that reduce the force needed to go over the top of the obstacle, but also the force needed when the vehicle comes back down.

A shock absorber is nothing more that a spring and a damper (some are pretty fancy). The ram is neither, but it does provide for the transfer of force to another part of the vehicle and for the movement of fluid, and where you have movement of fluid you can apply a valve to dampen the movement and I added springs to counter the weight. If you take the top half of both shocks, that is the same function that the center shocks in my 6 shock mechanical system was performing.

If you hit the front brakes, both front shocks start to compress, as they compress they also lower the rear end which reduces your dive. As you accelerate, the back compresses and as they compress it lowers the front end keeping it in touch with the ground and counter typical lift. As you corner and the outside tires start to compress, it compresses the inside shocks which lowers the inside ride height. This also lowers your roll center and center of gravity. The harder you corner, the more it compresses and the faster you can take the curve. You can set up for the corner by either touching the brakes...which lowers the vehicle, or hitting the gas...which lowers the vehicle...or just turn.

The valving on the shared top section of the two shocks is set for a spring weight and weight percentage of twice that of the individual shock. Instead of having to set the rebound slow because you have so much spring pushing you off a bump, the valving is set slower to correspond with the heavier weight and spring rate of the combined system and it is set faster of the individual cylinder, this means that the wheel can react quickly to stay in contact with the ground regardless of how deep into the stroke you are. More contact with the ground = more control.

Variables: There are so many ways to tune this for the performance you want. I arbitrarily set it at 50/50 for 50% wheel travel for individual shock and 50% travel for shared shock. You can have 25/75 or 75/25. You can have dual rate springs on the bottom to active the shared shock faster or dual rate on the top for quick initial and sharing and strong final hit. Same with the valving. So many options and it all will affect how the vehicle performs. There is a LOT of R&D to do on this system to really characterize the variables, but that's what R&D is all about.

This gives you a greater range of situations it can handle in one set up, it also allows for much more tuning for specific situations. It's a whole new game.



Floating shock bump.jpg
 
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Wicked Al

Well-Known Member
Matlab is more what you want as opposed to Catia. You won't need to run CFD. All the flow happening is simple pipe flow which can be estimated relatively easily. You need CFD for more complicated scenarios such as open flow, etc. This setup can definitely be reduced down to a system of equations and optimized. I predict hose sizing will of great importance to minimize "resistance" in the fluid channels. Where are you located again, Al?
I figured CFD is needed for the oil/viscosity, going through all of those valves, looking for laminar flow and cavitation. There will definitely be a trade off between system drag and mass as far as the size of the tubes are concerned, but I think there is enough info in the hydraulics industry that once we know volume, acceleration and velocity, the rest will be apparent. Beyond the system itself is the whole vehicle dynamics which is really the desired end result and should be modeled too in order to set the system up right. Deep pockets and a lot of expertise to do it right.

I reside in the beautiful Pacific North West. Lived in the Phoenix metro area for a bit, only thing I miss is the proximity to racing and resources to get anything done I needed. Now it just takes a little bit longer, but it still gets done. :)
 

Bricoop

Well-Known Member
Here is a graphic of one corner under compression and what that does. The blue and green are nothing more than the mechanical links, they sit on either side of the rams. As the shock is compressed that displaces one ram into the cylinder, that transfers the force over to the other cylinder and displaces that ram the same amount. The top of both of the connected shocks act in unison. When the fluid is displaced, it has valving it goes through that is for both tops of the shocks, compression and rebound. In this case, as the tire rolls over the rock, the brown, regular individual shock, compresses. Because the ram above it has to compress two springs, the bottom portion compresses 2 inches for every one inch of the top. Because it is connected diagonally, the rear passenger tire is being lifted up an inch, which in reality means that corner is dropping down an inch. That acts the same as a diagonal sway bar. Back to the rock you're going over. In a conventional system, when the front tire rolls over the rock and the shock compresses, it is lifting the vehicle up. It's like a long plank with a weight in the middle and you're lifting one end of it. With the Cross Link, as you start to lift the front, the back end is dropping down. Now it's like you have a long plank with weight on it, but there is a pivot point in the middle like a teeter totter. This means your center of mass is moving less to go over the same obstacle. Not only does that reduce the force needed to go over the top of the obstacle, but also the force needed when the vehicle comes back down.

A shock absorber is nothing more that a spring and a damper (some are pretty fancy). The ram is neither, but it does provide for the transfer of force to another part of the vehicle and for the movement of fluid, and where you have movement of fluid you can apply a valve to dampen the movement and I added springs to counter the weight. If you take the top half of both shocks, that is the same function that the center shocks in my 6 shock mechanical system was performing.

If you hit the front brakes, both front shocks start to compress, as they compress they also lower the rear end which reduces your dive. As you accelerate, the back compresses and as they compress it lowers the front end keeping it in touch with the ground and counter typical lift. As you corner and the outside tires start to compress, it compresses the inside shocks which lowers the inside ride height. This also lowers your roll center and center of gravity. The harder you corner, the more it compresses and the faster you can take the curve. You can set up for the corner by either touching the brakes...which lowers the vehicle, or hitting the gas...which lowers the vehicle...or just turn.

The valving on the shared top section of the two shocks is set for a spring weight and weight percentage of twice that of the individual shock. Instead of having to set the rebound slow because you have so much spring pushing you off a bump, the valving is set slower to correspond with the heavier weight and spring rate of the combined system and it is set faster of the individual cylinder, this means that the wheel can react quickly to stay in contact with the ground regardless of how deep into the stroke you are. More contact with the ground = more control.

Variables: There are so many ways to tune this for the performance you want. I arbitrarily set it at 50/50 for 50% wheel travel for individual shock and 50% travel for shared shock. You can have 25/75 or 75/25. You can have dual rate springs on the bottom to active the shared shock faster or dual rate on the top for quick initial and sharing and strong final hit. Same with the valving. So many options and it all will affect how the vehicle performs. There is a LOT of R&D to do on this system to really characterize the variables, but that's what R&D is all about.

This gives you a greater range of situations it can handle in one set up, it also allows for much more tuning for specific situations. It's a whole new game.



View attachment 206106
Really interesting, is there any concern with the lag between the compression on the front shock shock and the time it takes for that pressure to transfer to the rear shock? Are you transferring fluid or gas through the lines? Thanks for the reply.
 

michael.gonzalez

Well-Known Member
Really interesting, is there any concern with the lag between the compression on the front shock shock and the time it takes for that pressure to transfer to the rear shock? Are you transferring fluid or gas through the lines? Thanks for the reply.
Fluid is anything that flows. It can be liquid or gas. In this case, he will use liquid. Liquids are generally incompressible which is what you want in this scenario. The pressure should transfer at the speed of sound in the medium (in this case the speed of sound through shock oil) so lag is almost negligible. What is not negligible is the pressure LOSSES due to flow. This is were pipe/tube/line diameter becomes important.
 

Wicked Al

Well-Known Member
Really interesting, is there any concern with the lag between the compression on the front shock shock and the time it takes for that pressure to transfer to the rear shock? Are you transferring fluid or gas through the lines? Thanks for the reply.
What Michael said. In theory I could have an open chamber to share the fluid between the top ram and the bottom shock. The problem with this is the nitrogen in the reservoir is compressible which can create a lag from front to back when the ram is in movement and also a misalignment of the rams relative to each other.

I would think in actual practice you would have steel hydraulic tubes connecting the diagonals with a short length of flexible tubing going from the steel tube to the shock cylinder, again, much like current hydraulics. The flexible piece could have some expansion in it, but that is mostly limited anymore with the quality of hydraulic hose manufacturing. You could do a hybrid system where the individual shock component is gas based instead of liquid, for example an air shock. It would still compress the hydraulic ram for the additional benefits that provides but with the smoothness of an air suspension. That is also covered by my patent as is 2 and 3 wheeled vehicles. In fact, 3.0 makes a cross linked motorcycle much more viable.
 

michael.gonzalez

Well-Known Member
Do you need 4 separate air reservoirs? Some part of me thinks 1 air reservoir would do but I think that might add complexity to the system rather than simplify it.
 

Wicked Al

Well-Known Member
Do you need 4 separate air reservoirs? Some part of me thinks 1 air reservoir would do but I think that might add complexity to the system rather than simplify it.
The reservoirs I show is just to show how an advanced shock might be set up. You could run monotube shocks in the lower section with no reservoir. The lower section is responsible for the individual wheel action, sharing it would change the dynamics. The 6 shock equivalent system you see here has two layers of control. Individual and paired. The seven shock equivalent system has three layers of control, individual, paired and all four where the action on all corners are tied together like the pair system here is. That can have one reservoir and it affects all wheels. The seven shock system has different pros and cons than the six shock system. For all around use I like the six shock (equivalent) system.
 

Wicked Al

Well-Known Member
So we checked out the articulation yesterday. Not bad considering it still has full anti-roll capability. There's more room to improve on this too. We didn't have all of the parts back on it or any people in it. The additional weight would allow it to flex a bit more. The rear spring is still too tight, it's a dual rate 500/700 that will be changed to a 500/500 which will also give it more flex. Likin' it!
IMG-0669.jpg
 

Wicked Al

Well-Known Member
Driving is next! I finally wrapped up a presentation video and slideshow for shock manufacturers. I was at SEMA and AAPEX, spoke to a lot of shock manufacturers and need to follow up with them, great conversations! Next step is to take this system off, get it powder coated and in the meantime develop a course, and data gathering equipment and run it through the course with the stock shocks on it. Then it's a big swap over to the fresh powder coated stuff and do the obstacles again. We should get a lot of video from that along with a lot of data to crunch through and compare. In the meantime we need to work on building the prototype Cross Link 3.0 Floating Shocks. Once those shocks are done we can take the 1.0 system off again and replace it with the 3.0 system. I expect we'll have very similar results. Wish it could happen in 2 weeks, but it won't, I'm slow, might be a couple of months to get this all done.
 

michael.gonzalez

Well-Known Member
Triple all time estimates. I don't expect to see Cross Link 3.0 until early 2021 realistically. But sooner would be awesome!

Are you going to license to several shock manufacturers or give it all to a single manufacturer?
 

Wicked Al

Well-Known Member
Triple all time estimates. I don't expect to see Cross Link 3.0 until early 2021 realistically. But sooner would be awesome!

Are you going to license to several shock manufacturers or give it all to a single manufacturer?
Depends on the offer. I think it would be better to have general licenses to many manufacturers, but if one wants an exclusive and is willing to pony up...and does it before I grant a general license, I'm game. It's all open right now.

For the manufacturers, there will be a risk analysis. Do they wait until I have hard numbers and risk someone else getting a general license, or do they have their own guys figure out the benefits for their customers and just step up and make an offer now?

I have one LARGE company that's waiting for results, I have one small company that's eager to get a license with a small overlap in the marketplace. It will be interesting to see the different strategies they take. I'll get a better idea once I send these presentations out as I wasn't able to talk to all the right people while at the show and this presentation goes in greater depth.

Realistically, you are probably very close to accurate on your estimation assuming I can keep pushing things forward. I'd like to put ten people on it and have it done in a month, but I'm just one person with a few helpers here and there, we'll see!
 

Ty Owings

Well-Known Member
Ok, more fun. Betcha never seen a vehicle do this when you put a jack under it. :D

Would you mind sharing your background? Just curious to how you came up with this. I don't think an average internet fabber could even come up with something like this lol.
 

Wicked Al

Well-Known Member
Would you mind sharing your background? Just curious to how you came up with this. I don't think an average internet fabber could even come up with something like this lol.
Just being a problem solver. A little bit of art, a little bit of science. I tend to look at systems rather than items, this allows for some decent innovations. For example, for suspension most people look at shocks if they want a better ride. I race ATV's, I look at anything between the ground and my feet and hands as being a possible area to absorb shock. I developed an antivibe handlebar mount that works on three axis. ATV's are unique in how they convey forces as opposed to dirt bikes, this considers those forces. I also developed a handlebar mount with over three inches of travel in it, great for arm pump issues and reducing the amount of work your body does. Observation, solution, repeat. Don't be satisfied with the status quo. Oh, if you're into motors, I did a motor that can take power off of top dead center and a wind turbine that doubles the efficiency of vertical axis wind turbines. Observation, solution, repeat...from a systems perspective. If I can pull down a few dollars with this, I have an extreme terrain vehicle to build which will do for the SxS industry what this suspension does to standard shocks. Then I'm switching gears and seeing if I can change society for the better, I have ideas... To say I have a squirrel problem is an understatement :D.

I ask "why?" and "how?" a lot.

The Cross Link Suspension started as a custom ATV build and I was looking for more wheel travel constrained by width and length and a host of other constraints. I came up with the triple shock solution but still had issues with articulation. Why did I do a triple shock solution? I knew I had to control sway and a sway bar is nothing but an uncontrolled spring, so I made a controlled sway bar by making it rigid and adding a coilover shock to it at the same time made it responsible for half the wheel travel which means it had to be twice as strong as the outer shocks as it had to handle the full hit on the front end. This also gave the benefit of a higher progression and shared loading. It is a cross between a straight axle and IFS. Speaking of a cross, the rear suspension I did was an IRS on a swing arm...triple shocks, the center one being twice as strong. It looks different, but acts exactly the same way as the front. Cool stuff, 18" of front wheel travel and 20" of rear wheel travel but still didn't have full articulation. A part of this process was going through what I call mechanical logic. What is the state of the suspension in different scenarios and how do you want it to respond? In order to get it to respond a certain way, how to you link it up to achieve that? Observation, solution, repeat...from a systems perspective.

All it took me was taking what I had on the front, and instead of going across the front, going diagonal front to rear. This took away the movement dependency of the front left to the front right. It also gave all kinds of other advantages which leads me to believe it is the correct solution for a vehicle. In exploring this further, I came up with a multitude of configurations ranging from a 7 shock set up to a single shock set up, from 4, 3 and 2 wheels. Pros and cons with each configuration, it's a matter of choosing the one that has the attributes best suited for your application. Exactly what those attributes are is the subject of a lot of R&D, years and money. I'll leave that to the vehicle and shock manufacturers, I have an extreme terrain vehicle I want to build.

You can thank Cole Potts for this, seriously. During the 2017 Vegas To Reno, I was racing my ATV and he went though heavy dust, he didn't see me and took me out at about 70mph, lucky if I was doing 20 in the dust. Results were not good. During my recovery I was thinking about all of these things I had developed that weren't doing any good to anyone. What impact did I make on this world? During that accident, there were any of 100 things that if they happened differently, I wouldn't be here...what was my legacy? When I felt I could actually manage a project again, early this year, I started this business to move the Cross Link to market. Bottomline, you never know when your card is going to get pulled, so do what you can to leave a positive mark. I was supposed to be retiring, that's not working too well. Ha! But I'm having a lot of fun making a go of this thing and it will make a difference to a lot of people, especially if I can get it into the auto market. Of course there is the performance aspect of it, but with suspension, any improvement in performance is also an improvement in safety. What was once an out of control situation is now in control.

Does that answer your question? Or were you looking more for the resume type of answer? I don't do "normal" well. :D
 
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