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BOSCH REXROTH
LFA25EM-7X/CD40DQMG24
R900928440
Directional Seat/Poppet Valves

Logic covers: LFA 25.-7x/

$2,852.00

BOSCH REXROTH

MATERIAL:  R900928440

SUMMARY:  Logic covers: LFA 25.-7x/

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2-way cartridge valves are elements that have been designed for a compact block design. The power section with connections A and B is installed into the control block in a receiving hole standardized according to ISO 7368 and closed with a cover. In most cases, the cover is also the connection from the control side of the power section to the pilot control valves.

By control with respective pilot control valves, the power section can be applied for pressure, directional and throttle functions or a combination of these functions. Particularly efficient solutions are realized by adjustment of the size to various flows of the individual ways of an actuator. The application of power sections of elements for multiple functions is very cost-effective.

2-way cartridge valves generally consist of control cover (1) and installation kit (2). The control cover contains the control bores and optionally a stroke limitation function, a hydraulically controlled directional seat valve or a shuttle valve according to the required overall function. Additionally, electrically operated directional spool or seat valves can be installed at a control cover. The installation kit consists of a bushing (3), ring (4) (only up to NG32), valve poppet (5), optionally with damping nose (6) or without damping nose (7) as well as closing spring (8).

The function of 2-way cartridge valves is pressure-dependent. This way, three crucial pressurized areas A1, A2, A3 are realized for the function. The area at valve seat A1 is observed as 100 %. Depending on the version, the annulus area A2 realized by grading is 7 % or 50 % of area A1. The area ratio A1 : A2 is respectively either 14.3 : 1 or 2 : 1. The area A3 is identical to the sum of areas A1 + A2. Due to the different area ratios A1 : A2 and the resulting different annulus areas (A2), the area A3 is one time 107 % and another time 150 % of the area A1 at the seat, which is observed as 100 %.

In general, the following applies:

The areas A1 and A2 are effective in opening direction. The area A3 and the spring are effective in closing direction. The direction of action of the resulting force from the opening and closing forces determines the spool position of the 2-way cartridge valve.

The 2-way cartridge valves can be passed from A to B or from B to A. Pressurization of area A3 by pilot oil discharge from channel B or external pilot oil supply, channel A is blocked without leakage.

 

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

01

02

03

04

05

06

07

08

09

LFA

EM

7X

/

D

QMG24

Type

01

Control cover LFA

LFA

Size

02

NG 16

16

NG 25

25

NG 32

32

Version

03

Control cover version "EM"

Intermediate cover with electrical control of the closed position incl. installation kit with spool sealing and possibility of control cover fitting

EM

Component series

04

Component series 70 ... 79 (70 ... 79: unchanged installation and connection dimensions)

7X

Spool design

05

A1 : A2 = 2 : 1 (annulus area = 50 %; standard version)

CA

A1 : A2 = 14.3 : 1 (annulus area = 7 %)

CB

A1 : A2 = 1 : 1

CD

Cracking pressure

06

Cracking pressure 1.0 bar

10

Cracking pressure 2.0 bar

20

Cracking pressure 4.0 bar

40

Damping

07

Valve poppet with damping nose

D

Spool position monitoring

08

Electrical

QMG24

Seal material

09

NBR seals

no code

FKM seals

V

Version

„CA“

„CB“

„CD“

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/ technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/ technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Hydraulic fluid

Classification

Suitable sealing materials

Standards

Mineral oils

HL, HLP, HLPD, HVLP, HVLPD

NBR, FKM

DIN 51524

Bio-degradable

Insoluble in water

HETG

NBR, FKM

ISO 15380

HEES

FKM

Soluble in water

HEPG

FKM

ISO 15380

Containing water

Water-free

HFDU, HFDR

FKM

ISO 12922

Containing water

HFC (Fuchs Hydrotherm 46M, Petrofer Ultra Safe 620)

NBR

ISO 12922

Important information on hydraulic fluids!

For further information and data on the use of other hydraulic fluids, please refer to data sheet 90220 or contact us! There may be limitations regarding the technical valve data (temperature, pressure range, life cycle, maintenance intervals, etc.)! The flash point of the hydraulic fluid used must be 40 K higher than the maximum solenoid surface temperature.

Flame-resistant – containing water:

Maximum pressure differential at the seat 50 bar Pressure pre-loading at the tank port >20 % of the pressure differential; otherwise, increased cavitation Life cycle compared to operation with mineral oil HL, HLP 50 to 100 %

 

Size of the annulus area

Surface in cm2

Version

Size

16

25

32

A1

„CA“

1,89

4,26

6,79

„CB“

2,66

5,73

9,51

A2

„CA“

0,95

1,89

3,39

„CB“

0,18

0,43

0,67

Spool form (damping nose)

Size

16

25

32

Stroke

cm

0,9

1,17

1,4

Pilot volume

cm3

2,56

7,21

14,3

Theoretical pilot flow

1)​

l/min

15,4

43,3

86

Cracking pressure in bar

Version

Size

16

25

32

Direction of flow A to B

„CA10“

0,70

0,68

0,72

„CA20“

2,03

2,18

2,12

„CA40“

3,50

3,90

3,80

„CB10“

0,49

0,50

0,51

„CB20“

1,44

1,62

1,52

„CB40“

2,48

2,90

2,70

Direction of flow B to A

„CA10“

1,38

1,53

1,42

„CA20“

4,05

4,91

4,25

„CA40“

6,96

8,74

7,6

„CB10“

7,43

6,69

7,24

„CB20“

21,3

21,5

21,6

„CB40“

36,6

38,3

38,6

1) Switching time = 10 ms

general

Size

16 25 32

Ambient temperature range

NBR seals

°C

-30 … +60

FKM seals

°C

-20 … +60

MTTFD values according to EN ISO 13849 1)

Years

150
1) For further details, see data sheet 08012

hydraulic

Size

16 25 32

Maximum operating pressure

Without directional valve

bar

400

Anschluss A 1)

bar

315
350

Port B 1)

bar

315
350

Port X 1)

bar

315
350

Port Z1 1)

bar

315
350

Port Z2 1)

bar

315
350

Port Y

depending on the maximum tank pressure of the attached directional valve

With electrically monitored spool position

bar

400

Maximum flow 2)

l/min

25000

Hydraulic fluid

see table

Hydraulic fluid temperature range

NBR seals

°C

-30 … +80

FKM seals

°C

-20 … +80

Viscosity range

mm²/s

2.8 … 500

Maximum admissible degree of contamination of the hydraulic fluid 3)

Class 20/18/15 according to ISO 4406 (c)
1) dependent on the attached directional valve
2) NG-dependent; see characteristic curves
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.

For applications outside these parameters, please consult us!

(simulated with HLP46, ϑoil = 40±5 °C)

Size 16 (A → B)

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Size 16 (B → A)

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Size 25 (A → B)

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Size 25 (B → A)

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Size 32 (A → B)

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Size 32 (B → A)

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Notice:

The indicated characteristic curves have been determined without inserted springs.

Orifices

Thread

Orifice Ø in mm

M6 conical

0,5 … 3,0

M8 x 1 conical

0,5 … 4,0

G3/8

0,8 … 6,0

G1/2

1,0 … 8,0

Other orifices upon request.

Plug screws

Thread

Tightening torqueMA in Nm

M6

M8 x 1

7

G3/8

55

G1/2

80

G3/4

135

G1

225

G1 1/4

360

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

LFA . EM… (NG16 … 32)

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Inductive position switch type QM

The electrical connection is realized via a 4-pole mating connector (separate order) with connection thread M12 x 1.

electrical

Connection voltage (DC voltage)

Connection voltage (DC voltage)

V

24
+30 %/-15 %

Admissible residual ripple

%

≤ 10

Max. load capacity

mA

400

Switching outputs

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/
PNP transistor outputs, load between switching outputs and GND

Pinout

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

1

+24 V

2

Switching output: 400 mA

3

0 V, GND

4

Switching output: 400 mA

Switching logics

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Cartridge element (design as seat valve with damping noses)

Cartridge valves are hydraulically controlled seat or spool valves with two working ports A and B and one control port X or two control ports X and Z for the version with differential spool. Y is generally the leakage oil connection. The valves are available in sizes 16, 25, 32, 40, 50, 63, 80, 100, 125 and 160.

Criteria for determination of the size include the flow to be controlled as well as flow resistance values of cartridge valves and their area ratios.

Control cover

By means of control cover (2), the bore of the cartridge elements is closed. They also serve as connection element between cartridge valve and pilot control valve.

Pilot control valve

At control covers for set-up of a directional spool valve (3) or seat valve (4), the porting pattern is realized according to ISO 4401 and DIN 24340.

The cartridge element (1) and the control cover (2) form a functional unit. It is calibrated at the factory and must not be disassembled or combined with other third-party components.

The closed spool position is monitored by the attached position switch (5).

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/ technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Control cover (intermediate cover) “EM” with electrical control of the closed position, incl. installation kit and possibility of control cover fitting: NG16 … 32

Dimensions in mm

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

1

Position switch type QM

2

Angled mating connector (separate order, material no. R900082899)

3

Space required to remove the mating connector

4

Protective housing

5

Standard cover (separate order, see data sheet 21010)

6

Mounting screws not included in the scope of delivery

Notice:

The tightening torques stated are guidelines when using screws with the specified friction coefficients and when using a manual torque wrench (tolerance ± 10 %). The specified tightening torques were calculated with total friction coefficient μ = 0.14; adjust in case of modified surfaces.

Notice:

The dimensions are nominal dimensions which are subject to tolerances.

Hexagon socket head cap screws ISO 4762 - 10.9

Size

Quantity

Tightening torqueMA in Nm

16

4

32

25

4

110

32

4

270

Notice:

The tightening torques stated are guidelines when using screws with the specified friction coefficients and when using a manual torque wrench (tolerance ± 10 %). The specified tightening torques were calculated with total friction coefficient μ = 0.14; adjust in case of modified surfaces.

Notice:

The dimensions are nominal dimensions which are subject to tolerances.

NG

H1

H2

L1

▢ L2

L3

mm

mm

mm

mm

mm

16 50 15 80 46 65
25 50 24 85 58 85
32 50 28 100 70 100

Inductive position switches

Contactless position switches with integrated switching amplifiers are switched shortly before reaching the spool position to be monitored. The spool position reached is displayed by a binary signal.

Advantages of the position switches:

Short-circuit-proof Direct monitoring of the spool position at the control spool. Long life cycle High reliability due to no use of dynamic seals Reaction time of the switch upon operation approx. 15 ms.

Notice:

Valves with inductive position switches and proximity sensors in safety-relevant controls may only be assembled and commissioned by hydraulically and electrically trained specialists. Service work requires special tools and equipment. This work may only be performed by authorized specialists or in the factory!

Improper work at safety equipment leads to a risk of personal injury and damage to property!

The valve components are coordinated in the production plant and adjusted during assembly. They must not be interchanged. In case of valve or position switch defects, the complete valve must be exchanged! The factory setting of the position switch must not be changed. The position switch may only be set by Bosch Rexroth. The position switch must be automatically monitored by the machine control to prevent initiation of a new machine cycle even in case of a defect at the position switch.

Orifice selection

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Mating connectors for sensors and valves with connector “K24”, “K35” and “K72”, M12 x 1

4P Z24

technical illustration-LFA25EM-7X/CD40DQMG24-Logic covers: LFA 25.-7x/

Mating connectors for sensors and valves with connector “K24”, “K35” and “K72”, M12 x 1

4P Z24

For sensors and valves with connector “K24”, “K35” and “K72” Mating connectors M12, 4-pole, line cross-section 0.75 mm2

Data sheet

Spare parts & repair