Hydrostatic Drives Flashcards
What is a hydrostatic drive?
a fluid drive system that uses oil pressure hydraulic power to the make mechanical power.
What two principles of hydraulics are involved in a hydrostatic drive?
- Liquids have no shape of there own
- Liquids will not compress
What are the basic functional parts of a hydrostatic drive?
-pump
- Motor
What controls the volume and pressure of the oil?
Swashplate
What is a fixed displacement hydraulic pump or motor?
Displacement cannot be
changed
What is a variable displacement hydraulic pump or motor?
Displacement can be changed
by the use of the swashplate
Does the swashplate rotate?
No
Is there an advantage to a variable displacement pumps or motors?
pressure, flow, temperature.
What additional components are required to complete a hydrostatic drive?
Cooler
Pump
motor
Charge pumps
control valve
Filters
Reservoirs
In a hydrostatic motor, what is the position of the swashplate on in neutral?
Vertical
Why is there no high pressure oil in the motor in neutral?
No Oil needed
What is the position of the swashplate on the pump in forward?
Angled in open direction
Are the pistons of the pump against the swashplate?
Yes
What is the position of the swashplate on the pump in reverse?
Angled in opposite direction of forward
Does the pump reverse for reverse operation?
No
Can more than one hydrostatic drive unit be used on the same machine?
Yes
What are at least four advantages of hydrostatic drives?
1 Convenience
2 Single lever control for stepless
3 clutch-less
4 on the go changes of speed and 5 direction,
6 infinite variability
7 flexible location
8 Shift on the fly
If a machine equipped with a hydrostatic drive will not move, what are two possible causes?
- System low oil
- Faulty control linkage
If a hydrostatic drive system is noisy, what is the most likely cause?
Air in the System
A hydrostatic drive uses fluids at high pressures and relatively
low _____________
speeds
One of the principles of hydrostatics is that liquids will not _____________
compress
________________ is the quantity of oil a pump can move in one revolution.
Displacement
A fixed displacement motor does not have a ________________
moveable swashplate
If a given amount of oil out of a pump causes a motor to turn at a given speed, more oil will __________________
Speed up the motor
In a hydrostatic drive, the charge pump supplies ___________ to ___________
Make-up oil to the hydrostatic pump
Some of the possible pump and motor combinations are:
a) Fixed displacement pump and variable displacement motor.
b) Variable displacement pump and variable displacement motor.
c) Variable displacement pump and fixed displacement motor.
