Directional servo-valves in 4-way variant 4WSE3E 25

Description

• Size 25
• Component series 3X
• Maximum operating pressure 350 bar
• Maximum flow 1020 l/min

Features

• Valve to control position, force, pressure or velocity
• 3-stage servo valve with electrical position control of the control spool of the 3rd stage, position sensing of the control spool by means of an inductive position transducer
• 2-stage pilot control valve of size 6 with high dynamics
• 1st stage nozzle/flapper plate amplifier
• Filter for 1st stage freely accessible and replaceable from the outside
• For subplate mounting: Porting pattern according to ISO 4401
• Can also be used as 3-way version
• Valve and integrated control electronics are adjusted and tested
• Optimized valve control loop
• High response sensitivity, very low hysteresis and zero point drift
• Internal or external pilot oil supply and pilot oil return available
• Gap seals at pressure chambers of the control sleeve, no O-ring wear

Product description

Valves of type 4WSE3E... are electrically operated, 3-stage directional servo valves. They are mainly used to control position, force or pressure and velocity.

These valves consist of a 2-stage pilot control valve of type 4WS2EM 6 (1), a main stage with a main control spool in a sleeve (2), an inductive position transducer (3), and the integrated control electronics (4).

The pilot control valve (1) consists of an electro-mechanical converter (torque motor), a hydraulic amplifier (nozzle flapper plate principle) and a pilot spool in a sleeve, which is connected to the torque motor via a mechanical feedback.

Electric currents in the coils of the torque motor generate a force by means of a permanent magnet which acts on the armature, and in connection with a torque tube results in a torque. This causes the flapper plate which is connected to the torque tube via a bolt to move from the central position between the two control nozzles, and a pressure differential is created across the front sides of the pilot control spool. The pressure differential results in the control spool changing its position, which results in the pressure port being connected to one actuator port and, at the same time, the other actuator port being connected to the return flow port.

The pilot control spool is connected to the flapper plate or the torque motor by means of a bending spring (mechanical feedback). The position of the control spool is changed until the flapper plate position and hence the pressure differential across the nozzle flapper plate system becomes zero due to the feedback torque, which acts via the bending spring against the electro-magnetic torque of the torque motor.

In doing so, the stroke of the pilot control spool and hence the flow of the pilot control valve is controlled proportionally to the electrical input signal.

In the main stage, the main control spool (2) is operated by the pilot control valve and its position is sensed by an inductive position transducer (3). The position transducer signal is compared to the command value by integrated control electronics (4). Any possible control deviation is amplified electrically and fed to the pilot control valve as control signal. The pilot control valve starts to move and the main control spool is re-positioned.

The stroke of the main control spool and consequently the flow of the servo valve are controlled proportionally to the command value. It must be noted that the flow depends on the valve pressure differential.

The valve zero point can be adjusted by means of an externally accessible potentiometer.

The valves are set at the factory with a dither default setting with the constant frequency of 400 Hz.

Notice!

Changes in the zero point and/or the dither amplitude may result in damage to the system and may only be implemented by instructed specialists.

The pilot control valve may only be maintained by Bosch Rexroth employees. An exception to this is the replacement of the filter element.

Type code

Technical data

general

hydraulic

electrical

Diagrams/characteristic curves

(measured with HLP46, ϑOil = 40 ±5 °C)

Flow/load function with maximum valve opening (tolerance ±10 %)

Summated edge Δpv = 70 bar

Single edge Δpv = 35 bar (tolerance ±5 %)

Pressure-signal characteristic curve

Zero flow, total, with “D” overlap (pilot control valve and main stage), tolerance ±20 %

Zero flow Data valid for overlap "E"	Pilot control valve L1	l/min
	Complete valve qV	l/min
qvnom	Rated flow (complete valve) in l/min	210, 300, 380, 450
pp	Operating pressure in bar
Δp	Valve pressure differential in bar	70
qv	l/min	200, 300, 400, 500

Transition function with pressure rating 210 bar

Frequency response with pp = 315 bar - measured with pressure rating 315 barbar

Dependency of the frequency f at -90° of the pilot pressure - measured with 210 bar pressure rating

Transition function with pressure rating 315 bar

Frequency response with pp = 315 bar - measured with pressure rating 315 barbar

Dependency of the frequency f at -90° of the pilot pressure - measured with 315 bar pressure rating

Symbols/Circuit diagrams

Type 4WSE3E...

Symbol

With control spool symbol V, the following applies:
P → A: qVmax; B → T: qVmax
P → B: qVmax; A → T: qVmax
With control spool symbol V1-, the following applies:
P → A: qVmax; B → T: qV /2
P → B: qV /2; A → T: qVmax

Electrical connection

Supply voltage:

±15 V ±3 %, residual ripple < 1 %

+24 VDC / 18 ... 35 V; full bridge rectification with smoothing capacitor 2200 μF = Imax = 230 mA

Command value: A1, C1:

Reference potential at E and positive command value at D result in flow from P → A and B → T.

Reference potential at E and negative command value at D result in flow from P → B and A → T.

F1:

Reference potential at E and signal 12 to 20 mA at D result in flow from P → A and B → T.

Reference potential at E and signal 12 to 4 mA at D result in flow from P → B and A → T.

Actual value / measuring output:

The voltage / current signal is proportional to the control spool stroke and has the same sign as the command value.

Connection cable:

Recommendation:

• up to 25 m line length: Type LiYCY 7 x 0.75 mm2
  • up to 50 m line length: Type LiYCY 7 x 1.0 mm2

Connect shield to ⊥ only on the supply side.

Notice:

Electrical signals provided via valve electronics (e.g. actual value) must not be used to switch off safety-relevant machine functions!

Block diagram / pin assignment

Dimensions

Dimensions in mm

Dimensions in mm

To ensure proper operation of the servo valves, it is necessary to flush the system before commissioning.

The following values are guidelines for the flushing time per system: t ≥ V : QV x 5

t = flushing time in h

V = tank capacity in l

QV = Pump flow in l/min

When replenishing more than 10% of the tank capacity, the flushing procedure must be repeated.

The use of a directional valve with port according to ISO 4401-08-08-0-05 is suited better than a flushing plate. With this valve, you can also flush the actuator ports.

Symbol

Symbol

Accessories

Mating connectors for valves with round connector, 6-pole + PE

7P Z31

Mating connectors for valves with round connector, 6-pole + PE

7P Z31

• For valves with round connector according to EN 175201-804, 6-pole + PE as well as 6-pole, compatible with VG 95328

• Data sheet

• Spare parts and repair

Downloads

directional servo-valve in 4-way design Data Sheet | RE29621 | 2012-03-31 | English | PDF | 1.1MB Product Groups: Directional servo-valves 4WSE3E 25