lightweight rock crawler and Hydraulic drive options

[Baloo]

Here's one you guys should like

ok so whats the little red axle off then ?, it looks like an elctric motor on the top ?   and an oil or hydraulic filter, so whats going on here then,
and more importantly what you going to make with it  :-\



and you learn something new every day,  about  Alfalfa l mean

cheers andy

[Engineer]

The swather (like Spec posted the picture of) has a hydraulic motor driving each wheel.  It steers by just driving one faster than the other.  The upside would be the two driven motors (one for front and one for rear on a vehicle).  Most hydrostatic systems, like on a combine (harvester) usually only have one driven motor.  If using the swather system, I would just tie the two speed control levers together so both drove the same.

With the longer wheelbase, could you move the seats just slightly ahead of the carburetor in order to lower the passenger a bit?

I think welding the diff is a good plan, and the center brake as well.  Just size it up a little..... But remember the brake at the transaxle will take advantage of the ratio in the axles and seem quite a bit stronger.

I believe that Specs red axle is a self contained hydrostatic drive unit for a small tractor...  The pulley is where the power comes from the motor, and the fins are for keeping the pump and oil cool.  Looks like a nice heavy unit. 

O and Alfalfa is fed to horses alot as well.



edited for a spelling error    spec

[SPEC]

E-farmer is correct again that is a hydrostatic axle, capable of pushin a 23'' tall tired 800 pound tractor to 18 mph, plus run some other hyd' stuff off the aux. outlets

[Engineer]

O and Alfalfa is fed to horses alot as well.



edited for a spelling error    spec

Am I going to have to get K-fab over here to school you on the proper usage of a lot?

[SPEC]

 :P

[Baloo]

The swather (like Spec posted the picture of) has a hydraulic motor driving each wheel.  It steers by just driving one faster than the other.  The upside would be the two driven motors (one for front and one for rear on a vehicle).  Most hydrostatic systems, like on a combine (harvester) usually only have one driven motor.  If using the swather system, I would just tie the two speed control levers together so both drove the same.

so are you saying that the swarther in the pic in the link dosent have front wheels that turn via the steering wheel  ?   but turns  just buy speeding one  drive wheel up and slowing the other drive wheel down ?
if this is so does the steering wheel do this via valves on the column

how does this work in practice,  smooth, contolable, ?,  would it suit a rock crawler  and would it work ok if all 4 wheels were driven, sorry for so many questions l tend to think a skid steer rock crawler would be a bit clumsy ?   but it would be the least complicated to biuld

both left side motors connected in series and both right side motors connected in series ?    and two levers to control speed, that way you could have one side going forward and the other going backward and turn on a  sixpence ( dime )
 
certainly alot     to think about,  l have  a v twin engine and pumps, control gear, pipes, etc  on its way courtesy of Lee


Andy

[Baloo]

With the longer wheelbase, could you move the seats just slightly ahead of the carburetor in order to lower the passenger a bit?

I think welding the diff is a good plan, and the center brake as well.  Just size it up a little..... But remember the brake at the transaxle will take advantage of the ratio in the axles and seem quite a bit stronger.

back on the subaru powered rock crawler,  l think the wheel base would be to long by the time you had made enough room to sit in front or behind the engine,  but l think you could probally sit on top either by relocating the carb  or useing a later engine with fuel injection as injectors are no where near as tall as  carbutretters  ,  fuel injection would probally run a lot smoother off road than the carb anyway

l have 2 seperate rock crawlers running in my head now,  one hyd and one scooby powered,   no wonder l have a headache

still its something to keep me occupied 

Andy

[Engineer]

so are you saying that the swarther in the pic in the link dosent have front wheels that turn via the steering wheel  ?   but turns  just buy speeding one  drive wheel up and slowing the other drive wheel down ?
if this is so does the steering wheel do this via valves on the column

how does this work in practice,  smooth, contolable, ?,  would it suit a rock crawler  and would it work ok if all 4 wheels were driven, sorry for so many questions l tend to think a skid steer rock crawler would be a bit clumsy ?   but it would be the least complicated to biuld

both left side motors connected in series and both right side motors connected in series ?    and two levers to control speed, that way you could have one side going forward and the other going backward and turn on a  sixpence ( dime )
 
certainly alot     to think about,  l have  a v twin engine and pumps, control gear, pipes, etc  on its way courtesy of Lee


Andy

Sorry for the hijack, but I will try to clear the confusion on the swather.  The swather has a steering wheel.  It also has a speed control lever.  In the picture posted, the bared tires are the drivers and the tires to the right side are just followers.  They can pivot any direction freely.

There is a pump that drives each tire, and each one has a control lever.  If you move the lever one way the it's tire drives forward, if you move it the other way it's tire drives backwards.  The farther you move the lever the faster it goes.  There is a fancy linkage between the two pumps and the steering wheel/speed control lever.  When you push the speed control lever forward, both tires drive forward.  Then if you turn the steering wheel, one tire goes a bit faster, while the other tire goes slower and you start turning.  If you are not moving and you turn the wheel, one tire goes forward and the other goes backwards and you spin in a circle.  Just like a zero turn radius mower.

I was never suggesting to turn with the hydraulic motors like on the swather.  I envisioned directly coupling one motor to the (pinion) input of the front axle, and the other to the rear axle.  Then tie the two controls together so that they both work in unison.  You would have one control handle that would move both at the same time for forward or reverse.  If the rotation direction on the motors was a problem, you could make the two pump levers work opposite in order to fix it, or just swap one set of hoses.  And there is no need of a brake, because when you pull the handle to center, it stops instantly.

You would still tie in the steering of the front wheels with a steering wheel.  However if you built a hydraulic drive machine, it might be novel to make the steering hydraulic as well with a cylinder, so that you didn't have to get a linkage to the highly-articulated front axle.  Just hoses.

Ok hijack over.

On the seats, I was thinking it would only move the seat forward about 25CM (1 foot) in order to get the back edge of the seat right in front of the carburetor, so that it could drop down to the top of the crankcase.  (still on top the motor).

[fabr]

so are you saying that the swarther in the pic in the link dosent have front wheels that turn via the steering wheel  ?   but turns  just buy speeding one  drive wheel up and slowing the other drive wheel down ?
if this is so does the steering wheel do this via valves on the column

how does this work in practice,  smooth, contolable, ?,  would it suit a rock crawler  and would it work ok if all 4 wheels were driven, sorry for so many questions l tend to think a skid steer rock crawler would be a bit clumsy ?   but it would be the least complicated to biuld

both left side motors connected in series and both right side motors connected in series ?    and two levers to control speed, that way you could have one side going forward and the other going backward and turn on a  sixpence ( dime )
 
certainly alot     to think about,  l have  a v twin engine and pumps, control gear, pipes, etc  on its way courtesy of Lee


Andy

Think skid steer/bobcat

[SPEC]

Not neccisarily skid steer...There are a couple of routes to take at this point...
1) motor on each wheel, Direct drive.. still able to sTeer by turning wheels CONVENTIONALY LIKE BUGGY FRONTS...
2) Hook Hyd motors directly to the yolkes on the diffs
3) Articulate

I have all three of these drawn up on toilet paper not on cad...But I could get up a paint in a few days...Got MRI tomarrow

[plkracer]

I have all three of these drawn up on toilet paper not on cad...

Is that your medium of choice, or the only thing available at the time?  :P

[SPEC]

I do some of my best thinking there :P

[Baloo]

On the seats, I was thinking it would only move the seat forward about 25CM (1 foot) in order to get the back edge of the seat right in front of the carburetor, so that it could drop down to the top of the crankcase.  (still on top the motor).

l get your drift however the problem is going to be the dizzy, it sticks up nealy as high as the carb and is in front of it so the seat would have to go forwad until it clears the cylinder head before it can go down a reasonable amount
but if you were to turn the seat round so as it faces the other way not only would you have the seat of the proper side of the vehicle but you would be able lower it down to the crank case as there is no dizzy in the way , the diffs will flip on a sammy to ensure you have your full allocation of forward gears

[Baloo]

Sorry for the hijack, but I will try to clear the confusion on the swather.  The swather has a steering wheel.  It also has a speed control lever.  In the picture posted, the bared tires are the drivers and the tires to the right side are just followers.  They can pivot any direction freely.

There is a pump that drives each tire, and each one has a control lever.  If you move the lever one way the it's tire drives forward, if you move it the other way it's tire drives backwards.  The farther you move the lever the faster it goes.  There is a fancy linkage between the two pumps and the steering wheel/speed control lever.  When you push the speed control lever forward, both tires drive forward.  Then if you turn the steering wheel, one tire goes a bit faster, while the other tire goes slower and you start turning.  If you are not moving and you turn the wheel, one tire goes forward and the other goes backwards and you spin in a circle.  Just like a zero turn radius mower.

I was never suggesting to turn with the hydraulic motors like on the swather.  I envisioned directly coupling one motor to the (pinion) input of the front axle, and the other to the rear axle.  Then tie the two controls together so that they both work in unison.  You would have one control handle that would move both at the same time for forward or reverse.  If the rotation direction on the motors was a problem, you could make the two pump levers work opposite in order to fix it, or just swap one set of hoses.  And there is no need of a brake, because when you pull the handle to center, it stops instantly.

You would still tie in the steering of the front wheels with a steering wheel.  However if you built a hydraulic drive machine, it might be novel to make the steering hydraulic as well with a cylinder, so that you didn't have to get a linkage to the highly-articulated front axle.  Just hoses.

Ok hijack over.

l dont consider it a hijack, its all intresting stuff and food for thought

l understand now what you were suggesting, its some thing that l hadent considered,  probally because by using axles you take away one of the great plus points of hydraulic drive  Ground clearence,  this pic below shows something simalar.

 if l remember right its got a toyota supra engine driving a shaft behind the seats and then chains down each trailing arm to the hubs,  the ground clearence is huge, it makes the portal axle vehicle behind look low slung,  this is what l see as the big benifit of a hydraulic drive vehicle, plus simplicity if all the trailing arms are the same and it skid steers  you loose alot of components and hence wieght 
since it will have hydraulic power on board it would make sense if it could rise and fall on its suspension or lift a corner to climb over an obstical  ?   more thinking on that one

did you get the citroen 2cv over there ?  l was looking at the trailing arms on them for ideas




l guess you dident get them over there as l havent seen any buggys with the 600cc air cooled engine and 4 speed with REVERSE gearbox that also had disc brakes mouted on the gearbox outputs




if l am going to do some thing with hydraulics then l think it will have to be wheel motors as l have  6  of these and they way work is l dont think l will be buying new stuff for my toys







l think l might biuld a test rig for the 4 wheel motors and see how the skid steer perfoms, maybe just  a 2" box rectangular frame with a seat, 4 motors, engine pump and as few parts as l can get away with,  and then have a test in the back yard and see how good/bad the steering is

Andy

[Engineer]

Those hydraulic motors look good.  That extra ground clearance would be great if your going to hydraulic anyway.

What is a dizzy??  It's something on top the motor?