Tractor driven by hydraulics

[marcuswayne]

This tractor I built about 8 years ago.
I have a question about how to drive 4 hydraulic motors on my mini homemade 4 wheel drive articulated tractor. Each wheel has it own hydraulic motor on it and they are driven by a hydrostatic drive unit. I have a geared flow divider that supplies fluid to the two back hydraulic motors and the same to the front two hydraulic motors. The problem is if the back wheels have good traction the front wheels will spin. Or if the front wheels have good traction the back wheel will spin. I would like all the wheels to spin when pulling something. The geared flow divider is a 3 port unit. Fluid in and divided equally out in 2 ports.
Your help would be appreciated.

 

[Vigo327]

I believe a lot of systems pair the wheels diagonally. I believe you could put both circuits through the flow divider.

 

[oldnslo]

Another option is either a 4 section flow divider or another 2 section to feed the two flow dividers you currently have.

 

[ArlyA]

On pisten bully's the run a pump for each drive motor keep the left and right sides completely separated.

 

[marcuswayne]

I believe a lot of systems pair the wheels diagonally. I believe you could put both circuits through the flow divider.

Out one side of the flow divider it supplies the two front wheel motors, out the other side of the flow divider it supplies the two back wheel motors.

 

[Vigo327]

Yes, but i believe thats the cause of your problem. Pairing the wheels diagonally would prevent your symptom of just spinning one end of the vehicle.

 

[marcuswayne]

I have been looking at Pressure compensated flow dividers. Should I have used a pressure compensated flow divider instead of a rotary flow divider proportional divider. The rotary flow divider is what I am using now.

 

[marcuswayne]

Yes, but i believe thats the cause of your problem. Pairing the wheels diagonally would prevent your symptom of just spinning one end of the vehicle.

How would I pair the frontend to the back of the tractor diagonally?

 

[oldnslo]

I have been looking at Pressure compensated flow dividers. Should I have used a pressure compensated flow divider instead of a rotary flow divider proportional divider. The rotary flow divider is what I am using now.

Marcus
The gear style should work just fine. From your description of circuit in your first post the Problem you currently have is all the flow can go to either the front or rear axle depending on traction. To prevent this and get true 4 wheel drive you need to have flow divider section feeding each wheel so either a single 4 section 4 flow divider or add the 3rd 2 section to divide flow evenly to feed your two existing flow dividers.

You will need to put an orifice between the two front and two rear motors to allow for turning so outside wheels can turn faster than inside wheels.

Diagonal suggestion is to have one 2 section flow divider feed left front and right rear and second other two wheels. The thought here is that you are always driving a wheel on each axle and opposite corners so one wheel should have traction

 

[marcuswayne]

Marcus
The gear style should work just fine. From your description of circuit in your first post the Problem you currently have is all the flow can go to either the front or rear axle depending on traction. To prevent this and get true 4 wheel drive you need to have flow divider section feeding each wheel so either a single 4 section 4 flow divider or add the 3rd 2 section to divide flow evenly to feed your two existing flow dividers.

You will need to put an orifice between the two front and two rear motors to allow for turning so outside wheels can turn faster than inside wheels.

Diagonal suggestion is to have one 2 section flow divider feed left front and right rear and second other two wheels. The thought here is that you are always driving a wheel on each axle and opposite corners so one wheel should have traction

oldnslo
This is very interesting to read thank you. What happens now is if the front wheels have good traction the hydraulic pressure go's up and the pressure in the back wheel stay low because the back wheel motors are turning. The gear flow divider is working right just higher pressure on the front lines or back lines, depending on which is slipping. If you put more power into the hydrostatic drive unit you can make both front and back motors spin.
The hydraulic line to the back wheels go's to a T then to each wheel motors and the same to the font wheel motors
Thank you for your help