Working Principle - SMC Networks AV2000 Manual

Soft Start-up Valve

Working Principle

w
e
r
q
1(P)
3(R)
Working
Pilot Pressure
valve conditions
condition
Low speed
1/2 P > P
P A
supply
ON
High speed
≤ P
1/2 P
P A
supply
Normal
≅ P
1/2 P
P A
operation
Quick
—
OFF
exhaust
Series
B
ON OFF
t
2(A)
y
B
Working description
When pilot valve w is turned ON by
energization or manual override, the
pilot air pushes piston A e and main
valve q downwardand opens main
q
valve while R por t
simultaneously. The air from P
portmoves to needle valve u, where its
flow is adjusted, and flows to A port.
The meter-in control of needle valve u
slowly moves the cylinder from A to B.
≤ P
When 1/2 P after the cylinder
P A
reaches B, piston B t fully opens and
increases rapidly as shown from C
P
A
to Dand becomes the same pressure as
P .
P
Since piston B t holds the fully open condition, during normal operation the
cylinder's speed will be controlled by the usual meter-out control.
When pilot valve w is turned OFF, spring r pushes piston A e and q upward
and opens R port while shutting off the air supply from P port.
The pressure difference generated at this time lets the check valve open y and
the residual pressure on the A port side is quickly exhausted from R port.
AV2000/3000/4000/5000
u
Pressure time chart
(Meter-out control) example
Initial Operation Return Stroke
closes
P
P
P
A
P (Atmospheric pressure)
R
A
Time
B-B
Cylinder drive circuit
(Meter-out control) example
P P
P
B
2
1 (P)
D
2 (A)
1
3 (R)
C
P P
P
1 (P)
2
2 (A)
1
3 (R)
P P
P
2
1 (P)
2 (A)
1
3 (R)
F.R.L.
AV
AU
AF
AR
IR
VEX
AMR
ITV
IC
VBA
VE„
A
VY1
G
PPA
AL
A
A
14-3-7