Considering building skid loader-lots of questions

[Tazza]

My origonal thought to control the loader was going to be the use of two individual valves, but in the Surplus Center catatlog I found an actual joystick loader valve. Are there foot pedal valves avalibe that could control a hydralic motor?

Yeah, any old control block will work just fine, Bobcat built their own as they had electric solenoids for the aux hydraulics and the newer ones have coils to lock out functions for safety.

 

[metalmeltr]

Yeah, any old control block will work just fine, Bobcat built their own as they had electric solenoids for the aux hydraulics and the newer ones have coils to lock out functions for safety.

I wanted to use a valve that was a foot pedal to control the drive motors.

 

[Tazza]

I wanted to use a valve that was a foot pedal to control the drive motors.

Using a valve for the drive system will not be smooth, you will also generate more heat. The beauty of the vairable displacement piston pumps is you pump only whats needed. When still, the pump does not move oil, this reduces heat and reduces load on the engine. So the system is more efficient., reduces heat so a smaller oil cooler is all thats required.
You actually generate more power with a piston pump like this too, even at low speed you have the same torque as you have the exact same pressure, just lower flow. What you have said you want it for, i don't see pushing power to be an issue, you really just need lifting strength.

 

[metalmeltr]

Using a valve for the drive system will not be smooth, you will also generate more heat. The beauty of the vairable displacement piston pumps is you pump only whats needed. When still, the pump does not move oil, this reduces heat and reduces load on the engine. So the system is more efficient., reduces heat so a smaller oil cooler is all thats required.
You actually generate more power with a piston pump like this too, even at low speed you have the same torque as you have the exact same pressure, just lower flow. What you have said you want it for, i don't see pushing power to be an issue, you really just need lifting strength.

I wan all the power to the ground I can get. One reason I plan to use a motor on each wheel.

 

[metalmeltr]

I wan all the power to the ground I can get. One reason I plan to use a motor on each wheel.

What do you guys think about using propane on a skid loader

 

[skidsteer.ca]

What do you guys think about using propane on a skid loader

Bobcat had propane fuel options for some of its gas powered loader. Personally unless you need to run it in a unventilated area a lot, propane is a pita.
Used a forklift with it once, every time it was low on fuel, it was out of service while the tank left the job to get refilled, instead of dumping a can of gas in it. Very hard on cylinder heads (valves and guides) as it burns to dry. Don't start well in cold climates.
As for 4 wheel motors, there is a reason every major skidsteer manufacture does not do this. In fact several in the case. Unneeded complexity, cost and parts. Difficulty balancing flow of oil from front to rear, and ......
You can get all the torque you need from one properly sized motor per side using proper gearing reduction.
Ken

 

[metalmeltr]

Bobcat had propane fuel options for some of its gas powered loader. Personally unless you need to run it in a unventilated area a lot, propane is a pita.
Used a forklift with it once, every time it was low on fuel, it was out of service while the tank left the job to get refilled, instead of dumping a can of gas in it. Very hard on cylinder heads (valves and guides) as it burns to dry. Don't start well in cold climates.
As for 4 wheel motors, there is a reason every major skidsteer manufacture does not do this. In fact several in the case. Unneeded complexity, cost and parts. Difficulty balancing flow of oil from front to rear, and ......
You can get all the torque you need from one properly sized motor per side using proper gearing reduction.
Ken

In aproperly bleed hydralic system two motors conected in series should operate idenically.

 

[Tazza]

In aproperly bleed hydralic system two motors conected in series should operate idenically.

I would stick with Diesel, more power at low RPM.
As for the drive motors, it has been done before but as ken said, proportioning them correctly.... Hooking them up in series won't work. Parallel is the only way as far as i'm aware of, if you put them in series the high pressure on the first motor is fine, BUT you must have a low pressure side which is the outlet, if you have pressure building up here the motor will simply stall. The fluid must pass through the outlet with little resistance.
Does that make sense? if you have equal pressure on both sides the motor simply can't turn. If it did, the first motor would spin faster than the other as all motors have internal leakage.
Parallel would work, but there is nothing stopping one motor spinning and one stalling on slipery ground, i believe this would make things a little hard to control at times. I would advise to do as the other skid steers have, one large motor and chains and sprockets running in an oil bath. I'm pretty sure the A series machines with all wheel steer use seperats motors on each wheel but they have speed sensors too so they know if one is moving faster than the other.