Rexroth Proportional Valve 4WRDE

Rexroth Proportional Valve 4WRDE Description

Rexroth 4WRDE are 3-stage directional control valves. They control the quantity and direction of a flow and are mainly used in control loops for different tasks.

They consist of the following assemblies:

- The 2-stage pilot control valve consisting of the control motor (1) and a hydraulic amplifier (5) designed as nozzle flapper plate valve and the control spool socket unit (6) as flow amplifier stage for actuating the 3rd stage (7).

- The 3rd stage (7) for flow control

- An inductive position transducer (8) the core (9) of which is attached to the control spool (10) of the 3rd stage.

The position of the control spool (10) is measured by an inductive position transducer (8). The signal linking of the valve control loop, the supply of the position measurement system and the control of the pilot control valve are carried out via control electronics integrated in the valve. The voltage difference created by the command/actual value comparison is amplified in the control electronics and supplied to the 1st stage of the valve as control deviation. This signal deflects the flapper plate (2) between the two control nozzles (3.1, 3.2). This creates a pressure differential between the two control chambers (11.1, 11.2). The control spool (4) is moved and releases a corresponding flow into the control chamber (12.1 or 12.2). The control spool (10) with the core (9) of the inductive position transducer (8) attached to it is displaced until the actual value corresponds to the command value. In the compensated condition, the control spool (10) is held in the position specified by the command value. The control spool stroke is proportional to the command value. For the control of the flow, a corresponding control opening results, depending on the position of the control spool (10) to the control edges (13), to which the flow is proportional. The 4WRDE valve dynamics are optimized via the electric gain. The control electronics is integrated in the valve (oscillator, demodulator).

Rexroth valve 4WRDE particularities

- The 3rd stage is basically set-up of modules of our proportional valves.

- With V control spools, the control edges of control spools and housings are ground in to each other.

- When the pilot control valve or the control electronics are exchanged, they are to be re-adjusted. All adjustments may be implemented by instructed experts only.

- The pilot control valve may only be maintained by Bosch Rexroth employees. An exception to this is the replacement of the filter and the sealing according to accessories list. It has to be ensured that during the assembly, the sealing is properly seated and the plug screw is tightened. The tightening torque for the plug screw is 30  Nm.

Notice:Changes in the zero point may result in damage to the system and may only be implemented by instructed specialists!

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Rexroth 4WRDE Features

4/3-way version

Subplate mounting

Porting pattern according to ISO 4401

Position sensing of the main control spool by means of an inductive position transducer

2-stage pilot control valve type 4WS2EM 6-2X/...

It is particularly suitable for the position, pressure, force and velocity control when there are simultaneously high requirements on the dynamics and the response sensitivity