cost of production

[North Country Tough]

Very interesting facts thanks for taking the time to educate,on some sleds a upgrade kit to a cogged belt is in use and works well,the issues I would see with the present AATV,s construction would be frame flex,debris,and bearing failure causing belt derailment and destroy the belt,whereas chain can take alot more "issues" as it were,how would you address that in a cost effective manner.NCT

[mudNmallards]

Personally I would like to see an investment partner in RI and develop and modernize the Max line. An 8 wheel (Hydromike) style with 60 chain probably would compete on an industrial scale. The T-20 has more overhead capability than currently offered. Everyone wants to put a Hydrostatic trans in a 6 and 8 wheeler and think that's progress. I think a properly designed "clean chain box" 8x8 with a t-20 would be very competitive, reliable and more efficient use of Hp.

Well, progress is really in the eye of the beholder so unless there is a new technology introduced I don’t see much in the way of progress.

There is no doubt the chain drive can be built competitively and with reasonable reliability ( as far as chains go) since they are in use all over the world but the loss of HP is another story. That’s where chains come in dead last and since the reason is rooted in the 1st and 2nd laws there is nothing that can be done to work around it until someone finds a loophole in the laws of physics.

There are really 3 major losses of HP in any type of a series drivetrain and 4 standard methods of transfer (direct couple, chain, belt or gearing and since I don’t believe any of these units have a gear train all the way down I’ll omit them) so assuming the drive is properly sized for the load and all other variables are equal, here is what you are dealing with.

The first loss is through the transmission where there is power transfer to a transmission and from the transmission to the final drive.

The second loss (in this case with these vehicles specifically) is where you are running chains or belts transferring force to each wheel.

The final loss ( again specifically in these vehicles) is where the system is fighting itself because of vehicle geometry and the terrain all the wheels are not turning at the same RPM and applying torque to surface evenly.

OK, those apply to any machine or vehicle and there is nothing known that will eliminate it so all that can be done is reduce it as best as possible.

The closest possible solution to achieve the impossible 1:1 perfect energy transfer is direct couple. (thus a motor per wheel) Depending on the type coupling you select you might get in the upper 90s. This application completely negates the losses from 1 and 2 and absorbs most of 3 by transferring the force to the fluid and the natural forces and dampening properties of fluid takes over.

The next best option is the cogged belt/pulley- the last and worst is the chain.

Heres why. Assuming the system is designed right, at proper tension and all variables are equal and considering that 3 above applies equally to both since they are all linked together

First is obvious. The belt/pulley arrangement weighs physically less than chains and sprockets. That means it takes less energy to start them moving and keep them moving. The savings in HP go into the wheel.

The second is rooted in the mechanical properties of chains and sprockets. The cogged drive belt is almost a perfect fit to the slots and given the tensile property of a belt the pulley is very close to utilizing 100% of the surface area to pull and there is almost zero backlash or mechanical resistance in the form of binding.

A sprocket is physically almost identical to a gear in this aspect. It only “pulls” on about 3 teeth. (the in running tooth, the next tooth which is under load and the outrunning tooth) The rest of the chain is just sitting there along for the ride. That’s bad enough but when the chain stretches the sprocket doesn’t so the sprocket will eventually resist the chain ( which is what starts the wearing process of the sprocket) Sadly, all the lubrication on earth cant stop it- all it can do is stretch the usable life a bit.

So, if one of the desired qualities is to maximize the HP to the wheel- the chain drive (in any application) will always be the least efficient option. Granted that’s offset by the simplicity and usually reduced price but that’s also offset by the required maintenance. When you add all the total costs of ownership a chain drive really costs the most and produces the least.

[jerseybigfoot]

Personally I would like to see an investment partner in RI and develop and modernize the Max line. An 8 wheel (Hydromike) style with 60 chain probably would compete on an industrial scale. The T-20 has more overhead capability than currently offered. Everyone wants to put a Hydrostatic trans in a 6 and 8 wheeler and think that's progress. I think a properly designed "clean chain box" 8x8 with a t-20 would be very competitive, reliable and more efficient use of Hp.

[mudNmallards]

I just wanted to put this out there, but you guys should also consider the heat that's produced by all those hydrostatic motors. The Mudd Ox 8x8 is hydrostatic drive, and it doesn't even have motors for each wheel, it has motors which drive chain to the axles (one or two per side I believe) and the machine is very prone to overheating. AATVs somewhat closed in drive compartments don't circulate much air and with all the heat produced from all the hydrostatic drive motors (one per wheel), even with electric puller fans running, I'm sure that the overheating would be an issue.

The Super Swamp Fox had a very limited run of hydrostatic drive systems, but they did away with them quickly because they were also very prone to overheating and they went back to the good old reliable T-20 transmission.

Oh yeah, heat is a hydraulic systems most deadly enemy and since all force is transmitted through the fluid it gets real hot real quick. If you don’t cool it- it will boil itself to death in short order. The good news is that because this is a mandatory requirement for almost every hydraulic system and there are all kinds of ways to cool it adequately.
You just need to figure out how many BTU’s the system is generating and size the cooling system accordingly. I’m nowhere near that point yet but my first thought would be dual exchangers (1 per side) with fans pulling engine heat also at the end of the circuit and maybe a kidney loop exchanger to filter and pre cool the reservoir before the fluid hits the pump.

[mudNmallards]

the walking beam (hendrickson) suspension would be ok for an 8x8 but a 6x6 would still have one rigid axel, it looks like it would ride smooth but if you ever drove a semi with a Hendrickson suspension I guarantee you'll feel every little crack in the road,if we all could sit down at a huge round table with a chalk board I'm positve with the caliber of open minds that we have we could reinvent the aatv.

I am NOT the suspension guy ( closest thing to a suspension I do is a torque arm for a gearbox or vibration dampers on pads) but we have an automotive designer on the team and I work close with him because if we decide to do a suspension, his decisions will have a direct effect on my final drive and what I have to do. If anyone has any specific questions about suspensions let me know and I’ll forward them and try to get you an answer. His information made us go back and seriously reconsider whether a suspension is really the way to go because of the necessary requirements to put one on the unit that would function properly and last along with being affordable.

We got a good class (and education) the other week when we were discussing suspensions for an application such as this so I’ll share some of the take away points I was given.
Any suspension that actually accomplishes something due to the shock factors will mandate a substantial metal frame and probably body as well because if the forces are not absorbed in a large mass it can tear itself off the unit.

His suggestion was a spring over strut design because it would allow for modular installation, independent wheel control, simplicity and be lighter when compared to other beefier designs as well as the cheapest way to go.

Unless you want to sacrifice some of the performance characteristics over uneven terrain by using a solid axle tube driving L&R wheels or half shafts with a heavy support per wheel, you would almost have to use a zeppa type CV axle.

Any suspension will require substantial “X” axis support more than the “Y” because weight, inertia, torque and the terrain itself will want to force the wheels/axles to bend inward under load. (“X” being linear forces along the wheel side and “Y” being the up/down movement so you are facing a caster/camber type force) Look under a vehicle- there will be a strut with rubber bumpers or sway bar holding the wheels and keeping them from folding in should the vehicle hit something. This goes back to that “substantial” frame and the associated weight along with the cost.

Those were some of the key points we were given. Looking back on some of the parts manuals here after Ben’s class looking specifically at the frame/axle relationships- I think I’m beginning to see why the majority of these vehicles don’t have a suspension. I’m sure in my mind that every manufacturer has thought about a suspension and probably experimented with some designs and I would be willing to bet they encountered everything he pointed out and decided that unless they completely redesigned the frame/tub it was not financially feasible. It certainly can be done mechanically but the question is can it be done financially and light enough.

[jpswift1]

I just wanted to put this out there, but you guys should also consider the heat that's produced by all those hydrostatic motors. The Mudd Ox 8x8 is hydrostatic drive, and it doesn't even have motors for each wheel, it has motors which drive chain to the axles (one or two per side I believe) and the machine is very prone to overheating. AATVs somewhat closed in drive compartments don't circulate much air and with all the heat produced from all the hydrostatic drive motors (one per wheel), even with electric puller fans running, I'm sure that the overheating would be an issue.

The Super Swamp Fox had a very limited run of hydrostatic drive systems, but they did away with them quickly because they were also very prone to overheating and they went back to the good old reliable T-20 transmission.

[mudNmallards]

what size motors you talking about and do you not need two pumps my predator has Eaton char-Lynn 4000 series hydraulic motors and Eaton manually controlled variable piston pumps I got my prices off the net if you can get them for that price that is awsome .......... I just relooked and they are around 700.00

Just give me a little leeway because I’m conferencing this week and all I have is my personal laptop so I don’t have my applications information with me so I’m answering somewhat from memory so I cant answer you “exactly” right now but will do a follow up post in about a week with more precise detail if you want or a PM.

In most cases Hydraulic motors are spec’d out by RPM and torque rather than hp and that price was off my head from a set of hydraulic reciprocating screens for a mine in Oz. I used reversing gerolers to accommodate shock factor if memory serves because it had to shuttle but I’ll check the BOM when I get back there.

My price would probably be substantially different because I’m a tier III industrial purchaser ( tier II in some cases because I don’t buy much of a lot of things) so consider about a 20-60% discount and no tax on industrial MRO depending on a number of variables such as type, volume, extra features and whatnot. That’s important because any manufacturer is going to get that same rating even if they start out as a Tier I- they will work into it. Also, if you hug your distributor and offer them some advertising usage (should it work) and tell them you are prototyping a new design, they will often donate some stuff or “find” factory rebuilds or warranty returns somewhere in their system at substantially reduced prices and even free sometimes. Many of them also have tons of “secret” applications and usage data because chances are someone else has also already experimented on the application you are using and you may find the distributor “smile” and see some crumpled up paper on the floor by the chair when he leaves. Don’t thow that paper away without reading it first. LOL (remember- they WANT you to be successful and they WANT you to use their product but much of this stuff is IP or other customer data so you cant just ask for it openly but [especially Eaton] are VERY capable of helping you)

I have not even begun sizing motors yet because until you have a gross weight, wheel size, desired ground speed and desired torque along with any reversing/braking capabilities you really cannot even begin the typing (gearotor, gearoler, vane, piston etc) and selection of flow etc. Since I’m not the designer of the frame/body and our group has not even come close to deciding operating parameters I have to wait for that. I just already know there is one sitting on the shelf ready to go- I just have to figure out which one it is. Since these systems have to be designed from the motor back the type and number of motors (6 or 8) and “everything else” will determine the pump size/type, engine size requirement, accumulators, cooling and reservoir size. ( not to mention any additional accessory loops you may desire) That will also tell you whether you can direct couple to the axle or whether you have to use a belt or sprocket configuration to either increase/decrease the RPM and torque at the wheel.

Regarding the number of pumps- that’s the beauty of hydraulics. Your prime mover and control piping have an almost infinite number of combinations. You can do a series system and have a pump per side driving each side or a single pump and control each motor independently (or together or left/right drive sides). That decision is best made after you decide how you want the system to work.

[kadookid]

the walking beam (hendrickson) suspension would be ok for an 8x8 but a 6x6 would still have one rigid axel, it looks like it would ride smooth but if you ever drove a semi with a Hendrickson suspension I guarantee you'll feel every little crack in the road,if we all could sit down at a huge round table with a chalk board I'm positve with the caliber of open minds that we have we could reinvent the aatv.

[Robinhood02]

nope never seen it before, but it apears the walking beam works LOL, why do they allways have to make them so big and bulky ?? that thing looks huge for an aatv

[azz7772]

yup

have you seen the wolverine before it is made in Saskatchewan but very pricey

[Robinhood02]

yup

[azz7772]

so who's in on designing and building a new machine ?? i can design and build the fiberglass tub and top molds for a proto, and i have an idea for the suspension on an 8x8 but it won't work on 6x6

walking beam?

[Robinhood02]

so who's in on designing and building a new machine ?? i can design and build the fiberglass tub and top molds for a proto, and i have an idea for the suspension on an 8x8 but it won't work on 6x6

http://www.6x6world.com/forums/max-atvs/16721-dear-recreative-industries-my-wish-list-you.html

[Outdoorsy74]

Hydrotraxx and Mud Ox have hydrostatic drives from what I've gathered.

When I first got my Max II I was thinking of using hydrostat motors (1 per side) to get the same turning/steering capabilities as my zero turn mower. Adding it in place of the jackshaft then chains or cog belts to the wheels. For suspension you could mount the motors inside backspaced wheels, run the hoses up inside with a protective loom, and the spindles would be mounted like trailer torsion axles into the frame.

As for the body- kevlar reinforced fiberglass or stamped steel, maybe even the high density hard plastic like a truck box material. The frame- dom tubing.

Just thinking out loud.

[azz7772]

I dont know where you got those figures but with Eaton their top end charlyn line motors come in at about $400-600 each and the pump is about 1,500 that would power all of them.

what size motors you talking about and do you not need two pumps my predator has Eaton char-Lynn 4000 series hydraulic motors and Eaton manually controlled variable piston pumps I got my prices off the net if you can get them for that price that is awsome .......... I just relooked and they are around 700.00