Page 42 - Linde - VT1 Modular, modular system for LSC manifold valve plates

4 | System components. Directional control valves variants. Distinction

Directional control valve with standard function type D — symmetrical function with A-B-tank
connection as a leakage discharge
Directional control valve types
The following directional control valves are available:
>> 25F1 VW25-CF25 for NG25 functions with track-drive function
>> 25F2 VW25-CF25 for NG25 functions with track-drive function

These directional control valves are usually used for tracked vehicles with an open circuit and external brake valve. They have sym-
metrical flow distribution between ports A and B. In the zero position, ports A and B are open to the tank with a leakage discharge.
The directional control valves also have an additional feature, which offers high-performance synchronization control. This is offered
only in the NG25.
>> Hydraulic actuation (pilot pressure max. 32 bar) is realized with the ports provided on the covers of the
VW directional control valves. Hydraulic opening begins at 7.5 ±0.5 bar (pump-to-function). *
>> Electro-hydraulic actuation is realized with the electro-proportional pressure reducing valves. Electro-hydraulic opening
beings at I= 430 ±10mA.*
>> The necessary pilot pressure (max. 32 bar) comes from the Pst port on the VT1EE.
* A volume of approx. 1 l/min flows from the pump to the function

Each VW directional control valve is configured with the following characteristics:
>> Flow characteristic of the valve spool
>> Other responses: see replacement parts.

Directional flow A / B DBV NLV
control valve at DpLS=20 bar in bar
25F1 320 / 320 No Yes
25F2 290 / 290 No Yes

circuit diagram

VW25-CF25 with NLV

42