hydro-static?

[Scupper]

Could someone explain how Hydro-Static works.

My brother has an old Cub Cadet lawn tractor with hydro static controls. He wants to make a log splitter and was wondering if he could use any of these controls to complete his project.

Thanks for any information or advise.

[Whoaru99]

This could be a long discussion....

Essentially, a hydrostatic drive is a variable displacement hydraulic pump connected to a hydraulic motor. Sometimes the motors are also variable displacement. So, within the range of the pump and motor displacements, you have variable speeds without really changing gears.

The hydrostatic pump starts in neutral - ie, not pumping any fluid. The displacement control causes the pump swashplate angle to increase at the operator command and pump more fluid. More fluid pumped to the motor, the faster you go. Sometimes you have a variable displacement motor so you can also have like a high and low range (bang-bang two speed motor) or a fully variable motor for an even greater range of speeds. For example as the pump displacement is increased to maximum speed is gained, then when the pump is maxed out, the motor displacement is changed from maximum towards minimum giving yet more increase in speed.

EDIT: Had to run and cut short.

Now, in hindsight, a hydrostatic theory of operation really does you not a lot of good. Without much knowledge of what's going on in a Cub Cadet, my first reaction would be that it's probably not suited for log splitter. The main reason that comes to mind is that hydrostatic systems are typically closed loop circuits in which the majority of the fluid circulates from the pump though the motor and back to the pump with a small percentage intentionally bled out of the circuit for cooling and filtering. If you were to drive a hydraulic cylinder, there is not really circulation of the fluid which I think would eventually (and quite possibly in short order) cause some problems for the pump.