Hydraulic pumps & Actuator A Flashcards
non positive pump that has an impeller that throws the fluid away from inlet by centrifugal force
centrifugal or radial flow pump
non positive pump which uses a propeller to move fluid axially from its inlet to the discharge
propeller pump
amount of leakage in positive displacement pump
5-15%
3 ways to change output of pumps
- use a flow control and relief valve built into discharge passage
- change the speed of the driver
- use a variable displacement pump
4 types of piston pump
in line axial
bent axis
rotary piston
radial piston
part of in line axial piston pump
carries the piston
rotating cylinder block
part of in line axial piston pump
slides back and forth in the cylinder to take in and discharge fluid
piston
part of in line axial piston pump
supports the piston and allow them to slide on the surface of the swash place
shoe
part of in line axial piston pump
retracts the piston on the inlet stroke
retractor plate
part of in line axial piston pump
stationary is set at an angle to the axis of the pistons that slide on its surface
swash plate
part of in line axial piston pump
stationary and has ports that allow fluid to flow in and out of the cylinder
valve plate
the output of a piston pump can be varied by controlling the length of the stroke, in line axial piston pumps can be adjusted by change the angle of this
swash plate
axial piston pump
swashplate is supported by
yoke and pivots
spring setting on load sensing pump
200-400 psi
part of in line axial piston pump
pivots the yoke in needle bearing fitted in the case
pintles
advantage of bent axis pump to axial piston pump
withstand high vacuum
length of stroke on bent axis pump is based on
the angle between cylinder block and drive shaft
how to stop flow of rotary piston pump
move reaction ring so its centre around the cylinder block
component of rotary piston pump ports fluid in and out of the cylinder
pintle
the flow of radial piston pump is pass through
the cylinder
vane pump need to be sealed at the shaft at this end
drive end
pumping elements of a vane pump
cam ring
rotor and vanes
cam ring on the vane pump is eccentric
true or false
true
unbalanced vane pump use a circular cam that is off centre
true or false
true
the vanes are held against the cam in unbalanced vane pump by 2 forces
centrifugal force
hydraulic pressure
balanced vane pump can be displaced by changing
the cam ring
vane pump direction is determined by look at the pump from the
drive end
when installing vanes, ensure that the trailing edge is on the side of the
feed notches
orientation of rounded tipped vanes
either way
swash plate control limits the maximum pressure in the system
pressure limiting compensator
swash plate control regulates the flow to suit any given load
load sensing compensator
moves swash plate to maximum angle in in-line axial piston
bias piston
pump that has a cylinder block that rotates around a stationary shaft called a pintle
rotary piston pump
how to increase stroke and flow in variable displacement rotary piston pump
moving reaction ring further off center
difference between radial piston pump and piston pump
radial piston pump has stationary cylinder block
vane pump with circular cam that is off center with respect to the rotor
unbalanced vane pump
vane pump with ellipitical cam
balanced vane pump
compact vane pump
balanced
what determines amount of fluid displaced on each revolution in vane pump
thickness of cam ring
size of throws
direction of rotation on vane pump is determined by what end
drive end
trailing edge of vanes should be on this side
side of feed notches
side rounded tip vanes need to be installed
any side
bearings used on external gear pump to control radial loads
needle bearing
gear on external gear pump with no axial thrust
herringbone
gear on external gear with axial thrust
helical
most quiet gear in external gear pump
herringbone
advantage on internal gear pump
compact and quieter
internal gear pump has less teeth on which gear
internal
seal inside internal gear between inlet and outlet
crescent
quietest gear pump and least dirt tolerant
geroter