Danfoss PVE Series 4 Technical Information page 11

Technical Information
Functionality
PVE, Series 4 for PVG 32/100/120 and PVHC
Pilot oil diagram
Set point
Electronics
The hydraulic subsystem moves the spool and thereby opens the valve for work flow. The heart in the
hydraulic subsystem is the solenoid valve bridge which controls the Pilot Pressure (Pp) on spool ends. It
consist of four poppet valves, the two upper are normally closed (NC) and the two lower are normally
open (NO).
The Pp will work against the PVBS neutral spring when the spool is moved out of blocked (neutral) and
together with the spring when going in blocked. This combined with a larger opening in the NO than in
the NC will give a faster movement towards blocked than out of blocked.
When the PVE is powered the solenoids are all put in closed state. To move the PVBS to the right NC1 and
NO4 are opened and NC3 and NO4 are kept closed.
The activation of the solenoid valves represents oil consumption and thereby also a pressure drop in the
pilot oil gallery. By simultaneous use of multiple PVE the Pp can fall and result in performance problems.
The two check valves next to the NO are anti-cavitation valves. The orifice to tank reduces tank pressure
spikes and can also be used for ramp function.
W
Warning
Obstacles for the Pilot oil pressure (Pp) can have direct influence on spool control. Reduced Pp will limit
spool control. Too high Pp can harm the PVE.
520L0553 • Rev GD • Jan 2014
NC1
LVDT
NO2
Pp
NC3
Spool
NO4
1.0 [0.039]
Tank
V310073.A
11