BOSCH REXROTH
LFA50DZ2-7X/210XY
R901225859
Directional Seat/Poppet Valves
Logic covers: LFA 50.-7x/
BOSCH REXROTH
MATERIAL: R901225859
SUMMARY: Logic covers: LFA 50.-7x/
Quantity in stock: 0
General
2-way cartridge valves for pressure functions are pilot-operated valves in seat or spool design. The power section designed as cartridge valve (1) is installed into a receiving hole standardized according to DIN ISO 7368 and closed with a control cover (2).
The pilot control valve (4) for manual or electrically proportional pressure adjustment is integrated into the control cover (2) or is installed on the control cover (2) as pilot valve with mounting dimensions according to DIN 24 340.
By combination of cartridge valves with the control covers, different pressure functions can be realized. .
Pressure sequencing functions
This function enables pressure-dependent connection of a second system.
The required switching pressure is set at the pilot control valve integrated into the control cover.
The pilot oil supply may either be realized externally (pilot oil port X) or internally (from port A via pilot oil ports X or Z2).
The pilot control spring chamber is directed via ports Y or Z1, depressurized to the tank.
Circuit examples
Example 1: (Circuit for pressure-dependent unloading of the low-pressure system)
In the illustrated circuit, the system is supplied via a high-pressure and a low-pressure pump. The system pressure pS acts externally from the high-pressure side via pilot oil port X on the pilot control valve, which sets the low-pressure side to depressurized circulation after the set pressure value is reached. The check valve RV (not included in the scope of delivery) prevents the connection of the high-pressure system with the now depressurized low-pressure system.
On reaching the pressure set at the pilot control spring, the pilot control valve is switched and the spring chamber of the main valve to the tank is unloaded. The main spool is opened and the connection A to B is released.
With the version LFA..DZW..., the required switching position can be selected besides the hydraulic circuit by means of an electrically operated pilot control valve (not included in the scope of delivery of the control cover LFA..DZ...).
Example 2: (Circuit for pressure-dependent connection of a second system)
With this circuit, system 2 is not connected before the pressure in system 1 complies with the specified value. Pilot oil discharge is realized internally from port A of the main valve.
General information on the control cover for the pressure sequencing function
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01 |
02 |
03 |
04 |
05 |
06 |
07 |
08 |
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LFA |
DZ |
‒ |
7X |
/ |
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Type |
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01 |
Control cover LFA |
LFA |
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Size |
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02 |
NG 16 |
16 |
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NG 25 |
25 |
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NG 32 |
63 |
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NG 40 |
40 |
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NG 50 |
50 |
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NG 63 |
63 |
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Version |
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03 |
Pressure sequence function |
DZ 1) |
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Adjustment type for pressure adjustment |
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04 |
Rotary knob |
1 |
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Sleeve with hexagon and protective cap |
2 |
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Lockable rotary knob with scale (H-locking according to automotive standard) |
3 |
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Rotary knob with scale |
4 |
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Component series |
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05 |
Component series 70 ... 79 (70 ... 79: unchanged installation and connection dimensions) |
7X |
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Pressure rating (max. adjustable sequencing pressure) |
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06 |
Set pressure up to 210 bar |
210 |
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Set pressure up to 315 bar |
315 |
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Set pressure up to 350 bar |
350 |
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Pilot oil flow |
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07 |
Internal pilot oil supply - internal pilot oil return |
no code |
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External pilot oil supply - internal pilot oil return |
X |
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Internal pilot oil supply - external pilot oil return |
Y |
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External pilot oil supply - external pilot oil return |
XY |
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Seal material |
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06 |
NBR seals |
no code |
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FKM seals |
V |
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| 1) Control covers type LFA..DZ... are combined with 2-way cartridge valves type LC..DB |
Additional preferred types and standard units are specified in the EPS (standard price list).
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Orifice symbol |
Symbol in ordering code |
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A** |
 |
A** |
 |
This orifice is designed as screw-type orifice. If an orifice is to be installed, the respective code letter with the orifice Ø in 1/10 mm has to be entered in the type designation. Example: A12 = Orifice with Ø1.2 mm in channel A. |
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Ø1,2 |
 |
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This orifice is designed as bore. No specifications are made in the type designation. (Orifice Ø in mm) |
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Z12 |
 |
 |
This orifice is designed as screw-type orifice. This is a standard orifice. No specifications are made in the type designation. (Orifice Ø in 1/10 mm) |
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general
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Size |
16 | 25 | 32 | 40 | 50 |
hydraulic
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Size |
16 | 25 | 32 | 40 | 50 | ||
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Hydraulic fluid |
see table | ||||||
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Hydraulic fluid temperature range |
NBR seals |
°C |
-30 … +80 | ||||
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FKM seals |
°C |
-20 … +80 | |||||
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Viscosity range |
mm²/s |
2.8 … 380 | |||||
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Maximum admissible degree of contamination of the hydraulic fluid 1) |
Class 20/18/15 according to ISO 4406 (c) | ||||||
| 1) | 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. |
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Hydraulic fluid |
Classification |
Suitable sealing materials |
Standards |
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Mineral oil |
HL, HLP |
FKM, NBR |
DIN 51524 |
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Bio-degradable |
Insoluble in water |
HEES (synthetic esters) |
FKM |
VDMA 24568 |
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HETG (rape seed oil) |
FKM, NBR |
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Soluble in water |
HEPG (polyglycols) |
FKM |
VDMA 24568 |
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Other hydraulic fluids on request |
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Steuerdeckel
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Size |
16 | 25 | 32 | 40 | 50 | |||
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maximum admissible operating pressure in port ... |
...X |
bar |
315 | |||||
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...Z2 |
bar |
315 | ||||||
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...Y |
static |
bar |
315 | |||||
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at pressure control |
depressurized (up to ≈ 2 bar) | |||||||
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...Z1 |
static |
bar |
315 | |||||
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at pressure control |
depressurized (up to ≈ 2 bar) | |||||||
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Adjustable sequencing pressure |
bar |
210 315 350 |
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For applications outside these parameters, please consult us!
Overview (basic symbols), Pressure sequencing function
LFA..DZ.-../ 210 315 350
Control cover with manual pressure adjustment
LFA..DZ.-../ 210 315 350 Y
LFA..DZ.-../ 210 315 350 X
LFA..DZ.-../ 210 315 350 XY
Attention!
Control covers type LFA..DZ... are combined with 2-way cartridge valves type LC..DB... (see ordering code)
Installation bore and connection dimensions according to ISO 7368
NG16 ... 63
Dimensions in mm
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5 |
Bore for locating pin (cover pin assembled according to DIN 24 342) |
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6 |
Information on porting pattern NG 16: Length L1 (axis x–y bores) is 80 mm |
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8 |
Bore for locating pin at function as main pressure relief valve (reposition cover pin for assembly accordingly) |
NG 16 to 50
Dimensions in mm
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1 |
Adjustment type "2" |
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2 |
Adjustment type "1" |
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3 |
Adjustment type "3" |
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4 |
Adjustment type "4" |
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5 |
Space required to remove the key |
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6 |
Locating pin |
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7 |
Name plate |
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8 |
Lock nut |
Notice:
The dimensions are nominal dimensions which are subject to tolerances.
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Mounting screws (included in scope of delivery) |
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Hexagon socket head cap screw according to DIN 912-10.9 |
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NG |
Quantity |
Dimensions |
Tightening torque in Nm |
|
16 |
4 |
M 8 x 45 |
32 Nm |
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25 |
4 |
M 12 x 50 |
110 Nm |
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32 |
4 |
M 16 x 60 |
270 Nm |
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40 |
4 |
M 20 x 70 |
520 Nm |
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50 |
4 |
M 20 x 80 |
520 Nm |
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NG |
Ø Orifice S** 1) |
Ø Orifice X** 1) |
Ø Orifice Y** 1) |
H1 |
H3 |
H4 |
L1 |
L2 |
L3 |
|
mm |
mm |
mm |
mm |
mm |
mm |
mm |
mm |
mm |
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| 16 | 0.8 | 0.8 | 1 | 40 | 16 | 20 | 65 | 105 | 39.5 |
| 25 | 0.8 | 0.8 | 1 | 40 | 24 | 20 | 85 | 110 | 53 |
| 32 | 1 | 1 | 1.2 | 50 | 28 | 25 | 100 | 115 | 60.5 |
| 40 | 1 | 1 | 1.2 | 60 | 32 | 36 | 125 | 125 | 62.5 |
| 50 | 1 | 1 | 1.2 | 68 | 34 | 36 | 140 | 140 | 70 |
| 1) | Orifice Ø, orifice M6 conical |