Unic URW295CR, Maintenance Manual

Page: 50 / 125

Piston
To be connected to tank
If no current flows through
the coil, spool is pushed up
so that pilot pressure will
not be applied to cylinder
for extension.
Core
Coil
spool
spuping 3
Spring 1
spring 2
Differential transformer
Pailot pressure
（
１
０
−
８
）
10.8 Description of acceleration cylinder function
When controlling through the radio remote controller, electric
current proportional to the movement of speed control lever flows
from the control box to the cylinder coil so that the iron core is
gradually magnetized accordingly.
The iron core and the spool facing each other with the spring
1 placed them move downward to lead the pilot
pressure to the piston for extension.
The cylinder extends to the position where the working force
of cylinder for extension controlled by movement of
spool and the force of spring 3 are balanced.
The position being balanced is
detected by the differential transformer
to provide feedback to the control
box which in turn sends next command
to the proportional solenoid.
3.0MPa (30kgf/cm )
2
Internal pressure changes from
0(zero) to 30㎏f/c㎡ according to
extent of opening of the spool.