Advertisement
2)
OPERATION
P
T
HYDRAULIC CIRCUIT
(1)
Hydraulic functional principle
Pilot devices with end position locks operate as
direct operated pressure reducing valves.
They basically comprise of control lever(A), two
pressure reducing valves, body(3) and locks.
Each pressure reducing valve comprises of a
plunger kit(5), a metering spring(7) and a
spring(11).
At rest, control lever(A) is held in its neutral position
by return springs(11). Ports(1, 2) are connected to
tank port T.
When control lever(A) is deflected, plunger kit(5) is pressed against return spring(11) and
metering spring(7).
Metering spring(7) initially moves docking rod(10) downwards and closes the connection between
the relevant port and tank port T. At the same time the relevant port is connected to port P. The
control phase starts as soon as docking rod(10) finds its balance between the force from metering
spring(7) and the force, which results from the hydraulic pressure in the relevant port(ports 1, 2).
Due to the interaction between docking rod(10) and metering spring(7) the pressure in the
relevant port is proportional to the stroke of plunger(5) and hence to the position of control
lever(A).
This pressure control which is dependent on the position of the control lever and the
characteristics of the control spring permits the proportional hydraulic control of the main
directional valves and high response valves for hydraulic pumps.
A rubber bellows(17) protects the mechanical components in the housing from contamination.
1 2
6-17
17
T
P
A
5
7
11
10
3
100D7RCV01
Advertisement
