Can anyone explain the difference in hydrostatic steering and hydraulic steering.
hydrostatic uses oil alone to control the steering.
Hydraulic, I would of thought refers to "power steering"? ie a mechanical steering system with hydraulic assistance
hydrostatic systems use a form of rotary control valve to supply oil to hydraulic ram/s on the vehicles steering with no actual mechanical connection between the steering wheel and road wheels. Here in the UK this system will be limited to a 20mph max speed. in design most orbitrol control valves will change from a control valve to a pump/control valve in the event of the engine stopping so that steering can continue, if a hose bursts.................its hold on time!!!
"Hydraulic steering"-ie power assisted is simply a conventional mechanical steering system but with a hydraulic ram/s to help turn heavy/hard to turn steering wheels. because of the retained mechanical system in the event of a power or hose failure you may still be able to control the vehicle (if your strong enough) hence to travel over 20mph here in the UK you need this type of system.
in heavy equipment power assisted is often a visible exterior addition to steering axles where as in modern systems including large trucks and off road vehicles the hydraulic assistance may be contained actually in the steering box. small vehicles, ie cars, vans and light trucks may use a mechanical steering rack between the steering wheels with the all the hydraulic components built in.
Hydraulic steering usually means some sort of pump providing extra effort to turn something. This assist is usually in the form of some kind of cylinder. The other term you might hear is differential steering. This uses a hydraulic motor to change speed to one final or the other to make the machine steer.
Hydrostatic steering refers to hydraulic pumps running hydraulic motors and varying the amount of oil to one or the other motor to affect a turn. Hystat dozers use one motor per track this way.
There are plenty of posts on this forum that do a better job of explaining this. Do a search on Hystat and differential steering to find a few.