Hydrostatic drive on articulating loader

[MossRoad]

yes needs to be able to carry a full ibc tote

If you're thinking of building a loader yourself with a 3000 pound lift capacity, it's gonna be expensive. I know you're doing it for the enjoyment of doing it, but man, it's gonna be expensive unless you have a source for cheap steel.

 

[Renze]

If you are toying with the idea of four drive motors, why not take four hub motors to which you can attach the wheel directly, as these are load bearing.

Then you can use a flow splitter to get a differential lock, and an adjustable reduction in a connecting line behind the flow divider, to get a limited slip differential..

 

[oldnslo]

I believe most articulated loaders of any size use a differential for front and rear axles to carry the load and most likely lower cost.

you have a lot of things to consider before purchasing any components for the drive train.

some of them are:
Machine weight
Degree of slope you want to climb at max weight
Tire diameter- rolling radius

these items can be used to determine
Tractive effort - draw bar pull desired which can then be used to calculate torque required per wheel or differential

this will then be used to calculate hydraulic motor size based on pressure differential across the motors

not trying to scare you just attempting to provide a little guidance on some of the basics for a travel drive system design

 

[Renze]

I believe most articulated loaders of any size use a differential for front and rear axles to carry the load and most likely lower cost.

The smallest, cheapest mini loaders use wheel motors.

If you have to buy miniloader axles at an OEM youre going to pay aftermarket prices, which puts you at 3/4 of the price of a factory loader.
Load bearing wheel motors are standardised industrial parts, with a lot more suppliers to choose from, which is willing to give you some discount on the 500% margin between wholesale in batches of 1000 at the factory, and the advised aftermarket price for consumers.

 

[robirot]

well the motor will be way cheaper compared to an aftermarket diff axle.
A used diff axle of a something like a suzuki jimny will propably be cheaper, but heavier then a 4 motor setup.

The main question first question for a 4 motor design will be the weight it needs to handle. If it is going to have a 3k lbspayload rating, and a 2 lbs weight itself, it still means that the front axle needs to be able to support a weight 5 k lbs on a solid ground = 2,5 k lbs per hub. Also counting in that you will hit a bump hole from time to time, have no suspension. I assume it would be good to build every hub in s manner that it can handle 5 k lbs without any risking sheering. Not sure if a 1 1/4“ shaft will be able to support that (if you deduct the keyway the shaft is also reduced to about 1 1/16) or do you need a 2“ shaft? Also hard to get informations on the radial carrying capacity on most engines.

 

[Vigo327]

If cost is a concern I would just drive 2 solid rear axles from small trucks with 1 hydraulic motor each. Since the loader doesn't NEED suspension the axles can be hard mounted which means the motors DONT have to be hard mounted to the axles. That allows you to choose an additional reduction between them through a set of chain sprockets.

You could even choose to run the whole thing on ONE hydraulic motor through a belt drive. If you ran an idler pulley on the bottom of your center pivot point, you could run a belt from that to the front drive axle and the distances from that pulley to the driven axle on the driven front, and whatever is driving it on the back, would not change through articulation. You could also run the axles off driveshafts, perhaps using one 4wd transfer case with a motor as the input and the outputs feeding the axles. That would give you 2 spd ranges. If you chose to use a simple U-joint at your steering pivot, you'd get some speed variation as it spun at an angle, which may or may not be a problem depending on the rest of the system. For example, some all wheel drive transfer cases have a viscous coupling that could absorb that, and still lock up solid if shifted into '4 lock'. Or, you could use a constant velocity joint or 'double cardan' u-joint to avoid that problem.

In my opinion pretty much any automotive solid axle would be fine. I don't disagree with the momentary 5klb load rating concept, but forces that regular trucks encounter on the street aren't fully quantified and i think any truck carrying its full payload and hitting the bumpstops over a large bump probably does encounter 5k lbs momentary loadings anyway. If you want to talk about shear load, how thick is the 'neck' of a hitch ball, and how often does a hitch ball shear in half when a trailer gets rear ended? 5k momentary load, you think? Just letting up the clutch too quick on a manual truck hooked to a 5k lb trailer would be over a 5k lb load. Those things are skinnier than axle shafts.

I have a whole lot of articulated loader ideas but most of them are catered towards smaller machines probably ~42" wide and picking up only around 1000lbs.