RE 64602/2019-08-05, Bosch Rexroth AG
Contents
RE 64602/2019-08-05
Replaces: 2016-02
Pressure limitation and
feed valve, pilot-operated
Type MHDBN
Features
▶ Screw-in cartridge valve
▶ For mobile applications
▶ Pressure stages from 100 to 420 bar
▶ Available in 2 sizes (16, 32)
▶ Versatile applications for pressure limitation and feed
functions
▶ Sizes 16, 32
▶ Series 3X
▶ Maximum working pressure 420 bar
▶ Maximum flow 400 l/min
H567
Contents
Type code 2
Preferred types 3
Functional description 4
Technical data 5
Characteristic curves 7
Dimensions 9
Mounting cavity 10
Available individual components 11
Related documentation 11
Bosch Rexroth AG, RE 64602/2019-08-05
2 MHDBN | Pressure limitation and feed valve
Type code
Type code
01 02 03 04 05 06 07 08 09 10 11 12
MH DBN K 2 – 3X / *
Valve type
01 Mobile hydraulics
MH
02 Pressure limitation and feed valve, pilot-operated
1)
DBN
Size
03 Size 16
16
Size 32
32
04 Screw-in cartridge valve
K
Adjustment type
05 Grub screw with internal hexagon
2
Series
06 Series 30 to 39 (unchanged installation and connection dimensions)
3X
Pressure stage
2)
07 Set pressure up to 100 bar
100
Set pressure up to 420 bar
420
Pressure adjustment
08 Without pressure adjustment, without protective cap
3)
no code
With pressure adjustment, with protective cap
4)
–…
Pilot oil supply and pilot oil return
09 Pilot oil supply internal, pilot oil return internal
no code
Sealing material
10 NBR (nitrile rubber)
M
FKM (fluoroelastomer)
V
Mounting cavity
11 Size 16 M24 × 1.5
FH
Size 32 M33 × 1
FK
M36 × 1.5
LM
12 Further details in plain text
*
Notice
Valves set at the factory are protected by means of a
protective cap. In the case of subsequent re-adjustment,
the warranty will become void!
1) Minimum cracking pressure, see characteristic curves page 7
and 8
2) The values refer to the screw-in cartridge valve. If the valve is in-
stalled in a housing, it has to be made sure that the set pressure of
the screw-in cartridge valve does not exceed the value of the hous
-
ing that might be lower!
3) Protective cap separately available, material no. R900168151;
valves without pressure adjustment at the factory are delivered in a
pressure-relieved state.
4) Example:
Set to 300 bar: ...420–300...
(pressure adjustment at q
Vmax
= 10 l/min)
RE 64602/2019-08-05, Bosch Rexroth AG
3 Pressure limitation and feed valve | MHDBN
Preferred types
Preferred types
Type Material no. Mounting cavity
(see page 10)
Characteristic curves
(see pages 7 and 8)
MHDBN 16 K2-3X/420VFH R901162185 FH D1 / E2
MHDBN 32 K2-3X/100VFK R901162658 FK D4 / E6
MHDBN 32 K2-3X/420VFK R901162717 FK D4 / E6
MHDBN 32 K2-3X/420VLM R901162838 LM D4 / E7
Bosch Rexroth AG, RE 64602/2019-08-05
4 MHDBN | Pressure limitation and feed valve
Functional description
Functional description
General
The pressure valve type MHDBN is a pilot-operated pres-
sure relief valve for installation in block designs. It is used
to limit a system pressure. The system pressure can be set
steplessly via the adjustment spindle (4).
Pressure relief function
The valve is closed in initial position. The pressure in port P
acts on the spool (1). Simultaneously, pressure is applied
to the spring-loaded side of the spool (1) and to the pilot
poppet (6) via the nozzle (2).
If the pressure in port P exceeds the value set at the spring
(5), the pilot poppet (6) opens. Hydraulic fluid flows from
the spring-loaded side of the spool (1) via the nozzle (3)
and the channel (7) directly into port T.
The resulting pressure drop causes the spool (1) to move
and thus opens the connection from port P to T while
maintaining the pressure adjustment on the spring (5).
The pilot oil return is implemented internally via the chan-
nel (7) into port T.
Feed function
The feed function makes up for lacking hydraulic fluid
volumes caused, for example, by leakage when pressure
valves respond or in the case of leading loads.
If the pressure at port P is lower than the one at port T, the
spool (1) will be lifted out of its seat. Hydraulic fluid flows
from port T to port P.
Notice
▶ The maximum operating pressure is the sum of the set
pressure and the return flow pressure at port T.
▶ The pilot-operated pressure valves are virtually leak-
age-free thanks to their design.
▼ Section and symbol MHDBN
P
T
2 1 3 6 7 5 4
T
P
P = Pump port
T = Tank port
1 Spool
2 Nozzle
3 Nozzle
4 Adjustment spindle
5 Spring
6 Pilot poppet
7 Channel to port T
RE 64602/2019-08-05, Bosch Rexroth AG
5 Pressure limitation and feed valve | MHDBN
Technical data
Technical data
General
Weight kg See table on page 9
Installation position Any
Ambient temperature range °C –20 to +80
Storage temperature range °C –20 to +80
Surface protection Without – surface protection has to be ensured by painting the
components or the whole assembly (e.g. valve with housing).
Hydraulic
Maximum working pressure Port P
p
bar 100; 420
Port T
p
T
bar 50
Maximum flow
q
V
l/min See characteristic curves on page 7 and 8
Hydraulic fluid See table on page 6
Hydraulic fluid temperature range
ϑ
°C –30 to +80 (NBR seal)
–20 to +80 (FKM seal)
Viscosity range
ν
mm²/s 10 to 380
Maximum admissible degree of contamination of hydraulic
fluid, cleanliness level as per ISO4406 (c)
Class 20/18/15
1)
Load cycles 2 million
Notice
▶ Please contact us if the unit is to be used outside the
specified range of values!
▶ The technical data was determined with a viscosity of
ν=41mm
2
/s (HLP46; ϑ
oil
=40
±5
°C).
▶ Under application conditions with a working pressure
of <30bar and a flow of <30l/min, valves of another
design are to be selected from our valve program. The
maximum working pressure is the sum of the set pres-
sure and counter pressure!
▶ Minimum cracking pressure, see characteristic curves
page 7 and 8
1) The cleanliness classes specified for the components must be ad-
hered to in hydraulic systems. Effective filtration prevents faults
and simultaneously increases the life cycle of the components.
Available filters can be found at www.boschrexroth.com/filter.
We recommend using a filter with a minimum retention rate of
ß
10
≧ 75.
Bosch Rexroth AG, RE 64602/2019-08-05
6 MHDBN | Pressure limitation and feed valve
Technical data
Hydraulic fluid
Hydraulic fluid Classification Suitable seal materials Standards Data sheet
Mineral oils HL, HLP NBR, FKM DIN 51524 90220
Bio-degradable insoluble in water HEES NBR, FKM ISO15380 90221
soluble in water HEPG FKM ISO15380 90221
Notice
▶ Further information and details on using other hydrau-
lic fluids are available in the above data sheets or on
request!
▶ Restrictions are possible with the technical valve data
(temperature, pressure range, service life, mainte-
nance intervals, etc.)!
▶ The flash point of the hydraulic fluid used must be
40K higher than the maximum solenoid surface tem-
perature.
▶ Bio-degradable: When using bio-degradable hydraulic
fluids that are also zinc-solving, zinc may accumulate in
the fluid (700 mg zinc per pole tube).
RE 64602/2019-08-05, Bosch Rexroth AG
7 Pressure limitation and feed valve | MHDBN
Characteristic curves
Characteristic curves
▼ p
E
–q
V
characteristic curves – “D1”
4020 60 80
200
150
100
50
350
400
450
300
250
1000
Flow q
V
[l/min]
Pressure differential Δp [bar]
▼ p
E
–q
V
characteristic curves – “D4”
Flow q
V
[l/min]
Pressure differential Δp [bar]
16080 240 320
200
150
100
50
350
400
450
300
250
4000
= Performance limit
Notice
▶ Characteristic curves measured with HLP46,
ϑ
oil
=40
±5
°C.
▶ The characteristic curves apply to an output pressure
p
T
=0bar over the entire flow range and without
housing resistance.
▶ They refer to the specified nominal value of the pres-
sure stage (100, 420).
▶ Below the nominal pressure, the characteristic curves
become increasingly steeper.
Bosch Rexroth AG, RE 64602/2019-08-05
8 MHDBN | Pressure limitation and feed valve
Characteristic curves
▼ p
E
–q
V
characteristic curves – “E2”
Flow q
V
[l/min]
Pressure differential Δp [bar]
4020 60 80
3
2
1
6
7
8
5
4
1000
▼ p
E
–q
V
characteristic curve – “E6”
16080 240 320
6
4
2
12
14
16
10
8
4000
Flow q
V
[l/min]
Pressure differential Δp [bar]
▼ p
E
–q
V
characteristic curve – “E7”
16080 240 320
6
4
2
12
14
16
10
8
4000
Flow q
V
[l/min]
Pressure differential Δp [bar]
Notice
▶ Characteristic curves measured with
HLP46, ϑ
oil
=40
±5
°C.
▶ The characteristic curves apply to an
output pressure p
T
=0bar over the
entire flow range and without housing
resistance.
▶ They refer to the specified nominal value
of the pressure stage (100, 420).
▶ Below the nominal pressure, the charac-
teristic curves become increasingly
steeper.
RE 64602/2019-08-05, Bosch Rexroth AG
9 Pressure limitation and feed valve | MHDBN
Dimensions
Dimensions [mm]
Dimensions
▼ MHDBN…VFK
2
T
L2
SW1 SW2 SW3
⌀D1
L1
1 2
P
Type ØD1 L1 L2 Wrench size Tightening torque [Nm]
1)
Weight
[kg]
SW1 SW2 SW3 SW1 SW2
MHDBN 32 K2-3X/...VFK 37.0 40.9 46.1 34 16 5 150 15 0.40
▼ MHDBN…VFH / MHDBN…VLM
2
T
L2
SW1 SW2 SW3
⌀D1
L1
1 2
P
Typ ØD1 L1 L2 Wrench size Tightening torque [Nm]
1)
Weight
[kg]
SW1 SW2 SW3 SW1 SW2
MHDBN 16 K2-3X/...VFH 29.0 35.0 46.8 24 17 5 100 20 0.21
MHDBN 32 K2-3X/...VLM 41.0 47.4 46.0 36 17 5 150 20 0.45
P = Pump port
T = Tank port
1) Friction coefficients, tightening torques, and preload forces interact
with each other. The friction coefficients are influenced by the sur
-
face microstructure, material pairing, etc.
Thus, we recommend checking the mounting characteristics with
original components and under boundary conditions.
1 Lock nut
2 Internal hexagon
Bosch Rexroth AG, RE 64602/2019-08-05
10 MHDBN | Pressure limitation and feed valve
Mounting cavity
Dimensions [mm]
Mounting cavity
▼ Version “FH” (M24 × 1.5)
(Drawing no. R901148102)
2.4
+0.1
1
+0.1
R0.1
+0.1
R0.1
+0.1
0.008-/Pt 20
Rz
max
8
(min Ø30)
35
1)
min Ø
⌀30
+0.4
⌀27.2
+0.1
E
Ø18
H7
60°
±1°
20°
±1°
0.008-/Pt 20
0.008-/Pt 10
y
C
=
23
24.7
±0.1
26.5
±0.1
11
M24×1.5
⌀0.05 A B
⌀0.05 A B
A
B
⌀0.05 A
0.01
T
P
y
▼ Version “LM” (M36 × 1.5)
(Drawing no. R901148162)
35
+0.2
2.8
+0.2
0.5
+0.1
R0.1
+0.1
0.008-/Pt 20
Rz
max
8
44
1)
32
4)
18
3)
min Ø
⌀43
+0.4
⌀33
H7(+0.025)
⌀38.2
+0.1
E
15°
±1°
25°
±1°
45°
±5°
0.008-/Pt 20
20
M36×1.5
Rz1
max
8
c
⌀0.05 A B
⌀0.05 A B
A
B
⌀0.05 A
0.01
T
P
▼ Version “FK” (M33 × 1)
(Drawing no. R901148145)
20°
±1°
26
0.5
+0.1
2.5
+0.1
R0.1
+0.1
27
±0.1
28.8
+0.1
(Ø47)
37
1)
min Ø
M33×1
E
Rz1
max
8
c
⌀38
+0.4
⌀34.5
+0.1
Ø24
H7
15°
±1°
45°
±5°
0.008-/Pt 20
12
Rz
max
8
0.008-/Pt 20
⌀0.05 A B
⌀0.05 A B
A
B
⌀0.05 A
0.01
T
P
P = Pump port
T = Tank port
Rz 32
+0.2-0.2
2)
All seal ring insertion faces are rounded and free of burrs.
Standards:
Workpiece edges ISO 13715
Form and position tolerance ISO 1101
General tolerances for
metal-cutting procedures
ISO 2768-mK
Tolerance ISO 8015
Surface condition ISO 1302
1) Depth of fit
2) Visual inspection
3) Thread depth
4) Roughness up to ⌀32.5 required
5) Levelness up to ⌀32.5 required
RE 64602/2019-08-05, Bosch Rexroth AG
11 Pressure limitation and feed valve | MHDBN
Available individual components
Dimensions [mm]
Available individual components
100
999
Item Designation Sealing material Material no.
100 Protective cap – R900168151
999 Seal kit of the valve for mounting cavity “FH” FKM R961003387
Seal kit of the valve for mounting cavity “FK” FKM R961003389
Seal kit of the valve for mounting cavity “LM” FKM R961003398
Seal kits with other seals upon request.
Related documentation
▶ Mineral oil-based hydraulic fluids Data sheet 90220
▶ Environmentally acceptable hydraulic fluids Data sheet 90221
▶ Filter selection www.boschrexroth.com/filter
Bosch Rexroth AG, RE 64602/2019-08-05
12 MHDBN | Pressure limitation and feed valve
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97816 Lohr am Main
Germany
Tel. +49 9352 18-0
info.ma@boschrexroth.de
www.boschrexroth.com
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