4-Wheel Drive - Hydraulic skid steering
4-Wheel Drive - Hydraulic skid steering
(OP)
Hi Everyone,
I'm very new to hydraulics so please forgive me if my question is very basic.
I have a "tractor" that has hydraulic motors at each wheel. Each side has the front and rear motors setup in parallel with a 50/50 divider (http s://www.su rpluscente r.com/item .asp?item= 9-1048-C&a mp;catname =hydraulic) that is supposed to allow equal flow to the front a back wheels. Steering works via valves by the operator that change the pressure going to each side resulting in skid steering.
Now on our latest revision we've added a tank-track to each side (chains going all the way around both tires coupling them together) so that it can have better traction. We're finding now that the wheel couplers are breaking where they before the tank track they weren't.
Trying to diagnose the problem, we're trying to figure out if it's hydraulics related or just that the couplers are under-designed for the forces we've been putting through them.
So because the wheels are now coupled together externally via the tank track, is there fighting between the motors if they're not spinning perfectly at the same rate or does this setup account for that?
Appreciate the help!
- Mike
I'm very new to hydraulics so please forgive me if my question is very basic.
I have a "tractor" that has hydraulic motors at each wheel. Each side has the front and rear motors setup in parallel with a 50/50 divider (http
Now on our latest revision we've added a tank-track to each side (chains going all the way around both tires coupling them together) so that it can have better traction. We're finding now that the wheel couplers are breaking where they before the tank track they weren't.
Trying to diagnose the problem, we're trying to figure out if it's hydraulics related or just that the couplers are under-designed for the forces we've been putting through them.
So because the wheels are now coupled together externally via the tank track, is there fighting between the motors if they're not spinning perfectly at the same rate or does this setup account for that?
Appreciate the help!
- Mike





RE: 4-Wheel Drive - Hydraulic skid steering
Ted
RE: 4-Wheel Drive - Hydraulic skid steering
So then is the hydraulic setup ok you think in terms of the wheels forcing the motors or basically always turn at the same speed regardless of flow to each?
RE: 4-Wheel Drive - Hydraulic skid steering
Ted
RE: 4-Wheel Drive - Hydraulic skid steering
Mike Halloran
Pembroke Pines, FL, USA
RE: 4-Wheel Drive - Hydraulic skid steering
More common skidsteer drive is one motor for each side driving through a chain to both wheels on each side. The chain drive times the wheels and after-market over-the-tire tracks do not cause problems. No flow splitter.
Ted
RE: 4-Wheel Drive - Hydraulic skid steering
Thoughts?
RE: 4-Wheel Drive - Hydraulic skid steering
If not, you may have 'recirculating power', where the tracks equalize speed in ft/min at the rim of the wheels, and the flow divider equalizes flow or shaft rotation at the motor output, but the two may not be the same. Then one or the other must slip or create high forces to get the two synchronized.
I would not think the spool divider is that accurate, but it might be. Or, maybe the spool dividere is solid but is metering 48/52 instead of 50/50
Since the tracks equalize the wheel speeds, you don't need two devices doing the same thing. Pitch the divider if the tracks on or it.
There can be just a few hp or low torque going into a drive, but the connected path can produce very large torques in the components themselves, and break parts.
Search on foursquare gearbox testing: 4 gearboxes can be tested at very large torques internally, but only driving the arrangement with 10 or 20 hp.
Also steel wheel track or crane drives that use wheels on a rail. The drive into the first wheel from gearbox may use a much smaller roller chain than the chain between the two wheels.
RE: 4-Wheel Drive - Hydraulic skid steering
Man this forum is awesome. I've never posted but used it as a resource before and indeed the expert knowledge here is great! Hopefully I can contribute back in some of the other areas.
Thanks!
- Mike
RE: 4-Wheel Drive - Hydraulic skid steering
Engineering is not the science behind building. It is the science behind not building.