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BOSCH REXROTH
4WS2EM6-2X/20B11ET315K17EV-102
R900977832
Servo Control Valves

Servo valves: 4WS*2EM 6.-2x/

$9,730.00

BOSCH REXROTH

MATERIAL:  R900977832

SUMMARY:  Servo valves: 4WS*2EM 6.-2x/

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4WS(E)2EM 6-2X/…

Valves of this type are electrically operated, 2-stage directional servo valves with porting pattern according to ISO 4401-03-02-0-05. They are mainly used to control position, force, pressure or velocity.

These valves are made of an electro-mechanical converter (torque motor) (1), a hydraulic amplifier (principle: nozzle flapper plate) (2) and a control spool (3) in a sleeve (2nd stage) which is connected with the torque motor via a mechanical feedback.

An electrical input signal at the coils (4) of the torque motor generates a force by means of a permanent magnet which acts on the armature (5), and in connection with a torque tube (6) results in a torque. This causes the flapper plate (7) which is connected to the torque tube (6) via a bolt to move from the central position between the two control nozzles (8), and a pressure differential is created across the front sides of the control spool (3). The pressure differential results in the 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 control spool is connected to the flapper plate or the torque motor by means of a bending spring (mechanical feedback) (9). The position of the spool is changed until the feedback torque across the bending spring and the electro-magnetic torque of the torque motor are balanced and the pressure differential at the nozzle flapper plate system becomes zero.

The stroke of the control spool and consequently the flow of the servo valve are controlled proportional to the electrical input signal. It must be noted that the flow depends on the valve pressure drop.

 

Type 4WS2EM 6-2X/… for external control electronics

External control electronics (servo amplifier) serve the actuation of the valve, amplifying an analog input signal (command value) so that with the output signal, the servo valve is actuated in a flow-controlled form.

 

Type 4WSE2EM 6-2X/… with OBE

For amplification of the analog input signal, special control electronics (10) adjusted to this valve type have been integrated. They are attached to the connector (11) in the cover cap of the torque motor.

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

01

02

03

04

05

06

07

08

09

10

11

6

-

2X

/

B

ET

K17

V

*

01

Electrically operated 2-stage servo valve in 4-way version with mechanical feedback and external control electronics

4WS2EM

Electrically operated 2-stage servo valve in 4-way version with mechanical feedback and integrated control electronics (OBE)

4WSE2EM

02

Size 6

6

03

Component series 20 ... 29 (20 ... 29: unchanged installation and connection dimensions) - Size 6

2X

Rated flow at 70 bar valve pressure differential

04

2 l/min

2

5 l/min

5

10 l/min

10

15 l/min

15

20 l/min

20

25 l/min

25

05

Valves for external control electronics: Coil no. 11 (30 mA / 85 Ω per coil)

11

Valves with integrated control electronics:
command value ± 10 mA

8

Valves with integrated control electronics:
command value ± 10 V

9

06

Pilot oil supply internal, pilot oil return internal

ET

Inlet pressure range

07

10 … 210 bar

210

10 … 315 bar

315

Electrical connection

08

Without mating connector, with connector

Mating connector, separate order

K17

Control spool overlap

09

0 ... 0,5 % positiv

D

0 ... 0,5% negativ

E

10

FKM seals, suitable for mineral oil (HL, HLP) according to DIN 51524

V

11

Further details in the plain text

*

For applications outside these parameters, please consult us!

general

Type

4WS(E)2EM

Size

6

Component series

2X

Porting pattern

ISO 4401-03-02-0-05

Installation position

any – ensure that during start-up of the system, the pilot control is supplied with sufficient pressure (≥10 bar).

Storage temperature range

°C

-20 … +80

Weight

kg

1.1

Ambient temperature range

with OBE

°C

-20 … +60

without OBE

°C

-30 … +100

hydraulic

Type

4WS(E)2EM

Maximum operating pressure

bar

315

Maximum operating pressure

Port A

bar

315

Port B

bar

315

Port P

bar

315

Return flow pressure

Port T

bar

Pressure peaks < 100, static < 10

Rated flows qv nom at 70 bar valve pressure differential (35 bar/control edge) 1)

l/min

2

Maximum control spool stroke possible 2)

%

120 … 170

Hydraulic fluid

see table

Hydraulic fluid temperature range

°C

-30 … +80

preferably

°C

+40 … +50

Maximum admissible degree of contamination of the hydraulic fluid, cleanliness class according to ISO 4406 (c) 3)

Class 18/16/13 according to ISO 4406 (c)

Viscosity range

mm²/s

15 … 380

preferably

mm²/s

30 … 45

Feedback system

mechanical

Hysteresis (dither-optimized)

%

≤ 1.5

Range of inversion (dither-optimized)

%

≤ 0.2

Response sensitivity (dither-optimized)

%

≤ 0.2

Pressure amplification with 1 % control spool stroke change (from the hydraulic zero point) 4)

%

≥ 50

Zero adjustment flow over the entire operating pressure range 5)

%

≤ 3

Zero shift upon change of

Hydraulic fluid temperature

%/20° C

≤ 1

Ambient temperature

%/20° C

≤ 1

Operating pressure 80 … 120 % of pP

%/100 bar

≤ 2

Return flow pressure 0 … 10 % of pP

%/bar

≤ 1
1) Tolerance ±10 % with valve pressure differential Δp = 70 bar
2) With mechanical end position (in an error case) related to nominal stroke
3) The cleanliness classes specified for the components must be adhered to in hydraulic systems. Effective filtration prevents faults and simultaneously increases the life cycle of the components. For the selection of the filters, see www.boschrexroth.com/filter.
4) of pp from the hydraulic zero point
5) long-term ≤ 5%

Zero flow (with spool overlap "E", measured without dither signal)

l/min

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

Hydraulic fluid

Classification

Suitable sealing materials

Standards

Mineral oils and related hydrocarbons

HL, HLP

NBR / FKM

DIN 51524

For more information and data on the use of other hydraulic fluids please contact us.

electrical

Type

4WS(E)2EM

Size

6

Protection class according to EN 60529

IP65 (with mating connector mounted and locked)

Type of signal

analog

Inductivity 1)

Serial connection

H

1

Parallel connection

H

0.25
1) With 60 Hz and 100% rated current

(measured with HLP32, ϑOil =40 ±5 °C)

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

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

Tolerance field of the flow/signal function with constant valve pressure differential Δp

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

Transition function with pressure rating 315 bar

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

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

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

Dependency of the frequency f at -90° of the operating pressure and the inlet amplitude

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

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

Type 4WSE2EM 6...

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

Type 4WS2EM 6...

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

Type 4WS2EM 6...

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

The coils are connected in parallel in the mating connector or to the amplifier (see figure). For serial connection, contacts B and C have to be connected. The bridge E-F can be used for electrical recognition of the correct connection of the connector or for cable break detection.

Electrical control from A (+) to D (-) provides for the direction of flow P → A and B → T. Reverse electrical control provides for direction of flow P → B and A → T.

Type 4WSE2EM 6...

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

Pin assignment

Contact

Current control "13"

Voltage control "9"

Supply voltage (tolerance ±3 %, residual ripple <1 %)

Current consumption

A

+ 15 V,

max. 150 mA

+ 15 V,

max. 150 mA

B

- 15 V,

max. 150 mA

- 15 V,

max. 150 mA

C

Command value

D

±10 mA; Re = 1 kΩ

± 10 V; Re ≥ 8 kΩ,

Ie = 1,2 mA

Command value reference

E

F

not assigned

Command value:

Command value at the mating connector port D = positive against mating connector port E results in flow from P to A and B to T.

Command value at the mating connector port D = negative against mating connector port E results in flow from P to B and A to T.

 

Notice:

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

Connection line:

4- and/or 6-wire, 0.75 mm², shielded, with litz wires according to DIN VDE 0812 (e.g. line type LIYCY 4 and/or 6 x 0.75 mm²)

Dimensions in mm

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

1

Space required to remove the mating connector

2

Cap

3

Valve mounting screws (included in the scope of delivery):
4 hexagon socket head cap screws (SW4) ISO 4762 - M5 x 50- 10.9-flZn-240h-L
Tightening torque MA = 9.3 Nm

4

Identical seal rings for ports A, B, P, and T

5

Name plate

6.1

Mating connector, separate order

6.2

Mating connector, separate order

7

Connection line

8

Filter

9

Plug screw (SW6), after filter exchange, tighten it applying a tightening torque MA = 30 Nm

10

Dimensions in brackets for valve with integrated control electronics (OBE)

11

Machined valve contact surface; Porting pattern according to ISO 4401-03-02-0-05
deviating from the standard: Locating pin (G) not available

Subplates must be ordered separately

Dimensions in mm

Dimensions in mm

technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/ technical illustration-4WS2EM6-2X/20B11ET315K17EV-102-Servo valves: 4WS*2EM  6.-2x/

1

R-ring 9.81 x 1.5 x 1.78 (ports P, A, B, T)

2

Mounting screws (included in the scope of delivery):4 hexagon socket head cap screws ISO 4762 - M5 x 40- 10.9-flZn-240h-L, MA = 7 Nm ± 10 %

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 4401-03-02-0-05 is suited better than a flushing plate. With this valve, you can also flush the actuator ports.