190303gB Flashcards
What is a dual path hydrostatic system?
2 closed circuit hydrostatic drive systems that control the seed and direction of each track.
What are the basic components of a hydrostatic steering system?
2 variable displacement reversible pumps (engine driven) that send oil to the right and left variable displacement motors that are directly mounted onto the final drives.
What are two characteristics of a hydrostatic pump?
Swash plate can go to zero angle = 0 gpm & it can go over centre.
Two fetchers of a variable displacement motor?
The swash plate never goes to zero and never goes over centre.
I get max speed and torque out of a hydrostatic pump what angle must your swash plate be in?
Max angle for speed and min angle for torque.
I get max speed and torque out of a variable displacement motor what angle must your swash plate be in?
Min angle for max speed and max angle for high torque.
What are the advantages of a hydrostatic steering system?
Power to both tracks when turning.
Variable track and counter rotation ( manoeuvrability)
Ground speed can be adjusted for better traction.
What is the function of a change pump?
To keep closed circuit filled with oil
To provide oil to the control circuit
Provide a flow of oil to flush, cool & lub
What is the purpose of the neutral charge relief valve?
It limits the pressure in the charge circuit by dumping excess oil into the hydrostatic pump case for cooling and lubrication.
Where is the charge filter located in a steering system?
It is located in the outlet line of the charge pump.
Features of a hydrostatic pump in a steering system?
The two hydrostatic pumps are variable displacement, reversible, axle type piston pumps that control the forward and reverse of the tracks.
What do the hydrostatic variable displacement motor do in a steering system?
It controls the speed and torque that is transferred to the tracks.
Why are there check valves in a closed loop steering system?
The check valves allow oil into the close circuit system but not out.
What is the main purpose for a high pressure relief valve in a closed loop?
Two pressure relief valves are located in the closed system to control maximum pressure in the circuit.
What is the function of a flushing/shuttle valve?
It manages the pressure in the closed loop circuit.
