Freewheel on a hydraulic motor

[farlet]

Hello, I am wondering if you can help. I am building a forestry trailer and I want to have driven wheels to help in the bad ground. I have been told by a couple of people that if I use wheel motors with a valve block which has a freefloat position, then there will be very little drag when in free float. This would be perfect for my application as the wheels could freewheel most of the time and then put power to them when required.

Does anyone have any experience or thoughts on this one ?

Thanks for your help

 

[4570Man]

My skid steer rotary mower has a check valve across the lines which allows the mower to spin down at its own rate. You can spin the blade assembly pretty easily by hand in one direction but it’s locked in the other direction. If you had a ball valve across the lines it should allow you to free wheel in either direction but you’d have to close it to provide any power.

 

[MossRoad]

Hello, I am wondering if you can help. I am building a forestry trailer and I want to have driven wheels to help in the bad ground. I have been told by a couple of people that if I use wheel motors with a valve block which has a freefloat position, then there will be very little drag when in free float. This would be perfect for my application as the wheels could freewheel most of the time and then put power to them when required.

Does anyone have any experience or thoughts on this one ?

Thanks for your help

Don't forget, you have two hoses for power going to a wheel motor(and maybe a case drain hose). They are NOT in and out hoses. They are forward and reverse direction hoses. You'd need to address both directional hoses if you want the wheel motors to be able to be put into a free-wheel mode.

Think about the fluid in the motor and hoses. If you put that circuit into float mode, the wheels turning will be constantly circulating the fluid in a closed loop within the motor, hoses and valve block and back again. That will generate heat. I don't know how far you are planning on pulling the trailer in free-wheel mode, and I don't know how much heat it will generate, or even if it will be a problem. However, it WILL generate some heat, and that should be investigated.

 

[farlet]

Thanks for your replies, its good information. They say every day is a school day, well this is my first day at school ! I would be planning on using one of these motors :

Silnik hydrauliczny BMR chłonność: 160cm3/obr obroty: 375obr/min z łożyskowaniem do rębaka

Silnik hydrauliczny BMR 160 z ułożyskowaniem, przeznaczony do pracy w różnego typu urządzeniach

sklepdlarolnika.pl

The intention would be to operate in freewheel mode most of the time if I can find a solution with fairly little friction/drag. Then have the option to have power forward and back when required. Am I asking for the impossible or is there a way ?

Thanks

 

[workinonit]

Put some locking hubs on it.

 

[toolslinger]

I would think rather than just teeing across the lines, you could do a selector valve that would dump them both to the tank. It would be better if they went separately back to the tank so it had to flow through the tank, but even if they went to a common tank line, it isn't a confined circulation, so you don't have to worry about expansion. Still going to generate heat though.

Locking hubs are a solid solution. Not fast, but pretty bulletproof.

 

[workinonit]

If you are jheading into a situation that the hubs need to be locked you do so ahead of time. I'm sure at slow speeds you would not build up very much heat at all.

 

[MossRoad]

How are you planning to drive the wheels on the trailer?
Are you going to be pulling it with a tractor?
Is the tractor's hydraulic system going to power the wheels?
How many gallons per minute and what pressure flow do you have available?
You need to know that to size the wheel motors.
How are you going to account for speed changes between the tractor and the trailer when driving the trailer wheels?
Too slow and it's dragging, too fast and it's pushing, that kind of stuff.

 

[MossRoad]

Flow will also vary with engine RPMs.

 

[MossRoad]

Here's some interesting reading on two different ways this company drives their trailer tires.

FARMA 6.7-T10F 4WD

The model T10F is a variation of our model T9F but with hydraulic drive. Heavier axles and higher ply tires are used. We have 2 options for customers requiring assisted drive directly on their trailers. The ROBSON uses a rotating hydraulic motor in the treads of the tire to power the tires...

picken.ca