The Liebherr axial piston double pump DPVD series is developed for the open circuit in swash plate design. These variable displacement pumps are available in no- minal sizes from 108-108 to 165-165. The nominal pressure of the units is 400 bar and the ma- ximum pressure is 450 bar absolute. The model is available as a double pump with a back to back cation. Connecting the hydraulic lines is greatly simplified by a common suction port. The inverse drive with a swivel angle of 22° is very N efficient and has a very high power density. N The DPVD series is available with the most common controls. Valid for: DPVD 108-108 DPVD 165-165 Features: Series D Open circuit Regulator types: Load Sensing with pressure cut-off Volume electric with pressure cut-off Pressure range: Nominal pressure pHD N = 400 bar Maximum pressure pHD max = 450 bar Document identification: ID number: 12455455 Date of issue: 04/2017 Valid for: DPVD Autoren: Liebherr - Department VH13 Version: 1.1 Data sheet Axial piston double pump with variable displacement: DPVD
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Axial piston double pump with variable displacement: DPVD...The Liebherr axial piston double pump DPVD series is developed for the open circuit in swash plate design. These variable
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The Liebherr axial piston double pump DPVD series isdeveloped for the open circuit in swash plate design.
These variable displacement pumps are available in no-minal sizes from 108-108 to 165-165.
The nominal pressure of the units is 400 bar and the ma-ximum pressure is 450 bar absolute.
The model is available as a double pump with a back toback cation. Connecting the hydraulic lines is greatlysimplified by a common suction port.
The inverse drive with a swivel angle of 22° is very N
efficient and has a very high power density. N
The DPVD series is available with the most commoncontrols.
Valid for:DPVD 108-108DPVD 165-165
Features:Series DOpen circuit
Regulator types:Load Sensing with pressure cut-offVolume electric with pressure cut-off
Pressure range:Nominal pressure pHDN = 400 bar
Maximum pressure pHDmax = 450 bar
Document identification:ID number: 12455455Date of issue: 04/2017Valid for: DPVDAutoren: Liebherr - Department VH13Version: 1.1
Data sheet
Axial piston double pump with variable displacement: DPVD
Table of contentsAxial piston double pumpDPVD 108-108 / 165-165
NoteThe radial and axial loads depend on the load cycle, e.g. pressure, revolutions and direction of force.If planning a belt drive or continuous axial and/or radial forces are expected, pleasecontact Liebherr.
Nominal size 108 165
Torque at Vg max and Δp = 400 bar M max Nm 686* 1068*
Max. torque of drive shaft input(Installed without lateral force)
ME max Nm Values upon request
Ø in W40 W45
Max. torque of through drive MD max Nm Values upon request
*) Short-time pressure peaks of a max. 10 bar abs. are permitted (t <0.1 s).
2.4 Shaft lip seal
2.4.1 General information
The rotary shaft lip seals (RWDR) are special sealing elements which permit a specific housing pressure. To ensurethat the tribological system functions optimally, the operating conditions must be complied with.
Sealing edge temperature varies due to the following factors in the housing:- Circumferential speed- Hydraulic fluid temperature- Lubricating medium- Pressure build-up
The sealing edge temperature may be around 20 °C to 40 °C above the leakage oil temperature of a hydraulic axialpiston unit.
2.4.2 Temperature range
The FKM rotary shaft lip seal is permitted for leakage oil temperatures from -25 °C to +115 °C. For applications under -25 °C: please contact us.
Leakage oil pressure at connection T1/T2
Nominal size 108 165
Permanent absolute leakage oil pressure pL bar 3
Maximum absolute pressure pL max bar 6*
NoteThe pressure in the axial piston unit must always be higher than the external pressure on the shaft lip seal.
Selection of the appropriate hydraulic fluid is significantly influenced by the anticipated operating temperature rel-
ative to the ambient temperature, which is equivalent to the tank temperature.
Minimum required quality
2.5.2 Fill quantity
2.5.3 Filtering
- To maintain the specified purity class “21/17/14 according to ISO 4406” under all circumstances,filtering of the hydraulic fluid is necessary.
- The hydraulic fluid is filtered by the device-specific use of oil filters in the hydraulic system. - Cleaning and maintenance intervals for the oil filters and the entire oil circuit depend on use of the unit
(see the device-specific operating instructions).
ATTENTIONYou must not mix different mineral oil hydraulic fluids!
Specification
LH-00-HYC3A
LH-00HYE3A
NoteFor more information, see: www.liebherr.com (brochure: Lubricants and service fluids) Alternatively: Contact [email protected].
Nominal size 108 165
Fill quantity Litres 5.45 8.70
NoteBefore commissioning, the hydraulic unit must be filled with oil and vented. This process must be checked and repeated if necessary during operation and after long downtimes!
*) Depending on the hydraulic fluid that is used**) Relative to tank temperature
- Cold start phase:
- Warm-up phase:
- Normal operation:
ATTENTIONTemperatures ≤ -40 °C in the system = axial piston unit must not be operated.Pre-heat the axial piston unit to at least -40 °C.
Phase Temperature [ °C ]** Viscosity [ mm2/s ]*
Cold start phase -40 to -25 1600-1000
Warm-up phaseabove -25
1000-500
Normal operation < 500
Note
Optimum operating range: 16-36 mm2/s
The viscosity must not fall below 8 mm2/s (for a short period, thud < 3 minutes, 7 mm2/s) at maximumleakage oil temperature.
ATTENTIONThe following operating conditions must be maintained during the cold start phase:
• Operating pressure range: pHDmin < pHDcold start< 30 bar
• Speed ncold start ≤ 1000 rpm
Start the drive motor and operate the axial piston unit under the specified operating conditions until atemperature of at least -25 °C has been reached.
ATTENTIONThe following operating conditions must be maintained during the warm-up phase:
NoteOnly one nominal size is illustrated per regulator type or function, typically nominal size 108. Special ap-plications and designs are not included in this chapter. Always use the information from the installation drawing provided or contact Liebherr.
DANGERThe spring-guided reset in the regulating valve is not a safety device!Contaminants in the hydraulic system such as swarf or dirt from the device or system parts can causeblockages at undefined points of various regulator components.Under some circumstances, the machine operator’s specifications can no longer be implemented.It is the device or system manufacturer’s responsibility to install a safety device e.g. an emergency stop.
3 Type of drive and regulatorAxial piston double pumpDPVD 108-108 / 165-165
3.3 Regulator functions
- EL1 function/electro-proportional adjustment, see chapter 3.3.1- DA function / pressure cut-off, see chapter 3.3.2- LS function, Load Sensing, see chapter 3.3.3
3.3.1 EL1 function, rising characteristic
Characteristic
The EL function is designed with a positive characteristic as standard.
For the EL1 function, the displacement volume Vg of the axial piston unit is adjusted proportionally and continuously
via an electromagnet. The EL1 function is subordinate to the pressure cut-off (DA) function, i.e. the control current-dependent EL1 function only operates below the set value for the pressure cut-off.
As the control current (I) increases, the axial piston unit swivels from Vg min in the direction of Vg max to a large dis-
placement volume Vg by adjusting the drive.
The hydraulic fluid required for this purpose is taken from high pressure pHD. At a high pressure of pHD < 30 bar, the Fa connection must be supplied with auxiliary pressure of approx. 30 bar to guarantee that ad-justment is possible.
Safety function: If the activating signal is missing or defective, the axial piston unit swivels to Vg min.
3 Type of drive and regulatorAxial piston double pumpDPVD 108-108 / 165-165
3.3.2 DA function
Characteristic
The DA pressure cut-off limits the maximum high pressure of the axial piston unit in the regulator range. When a sethigh pressure value pHD is reached, the axial piston unit swivels in direction Vg min and the hydraulic system is pro-
tected against damage and overloading.
XE setting range: 30 - 400 bar
It continues to swivel in direction Vg min, until the generated flow equals the set high pressure value pHD.
If the system pressure falls below the fixed high-pressure value pHD, the axial piston unit swivels to Vg max.
3 Type of drive and regulatorAxial piston double pumpDPVD 108-108 / 165-165
3.3.3 LS function
Characteristic
The dynamic characteristics of the control system of variable axial piston pumps can be further improved by loadsensing (LS) systems. The LS function is designed as a so-called load pressure reporting system that adapts thevolume flow to the current requirements of one or more consumers. It reduces loss of performance compared toregulator functions that convey at maximum volume with lower required volume flow.
The pressure differential Δp between the highest LS pressure in the system (controlled via shuttle valves for multipleconsumers) and the high pressure pHD is compared at an external adjustable measuring orifice and kept in balanceby the pressure compensator (LS axis), which adjust to the demand from the consumers. The LS pressure dependson the spring force and can therefore be adjusted.
If there is no demand from consumers, the axial piston unit adjusts in direction Vg min, until the value is equal to the
set LS pressure. Δp = approx. 14-25 bar, depending on requirement.
If the demand from consumers increases (rising Δp at the orifice), the axial piston unit adjusts in direction Vg max,
until the working pressure pHD is equal to the sum of the demand-dependent LS pressure + Δp.
The installation variant for the device or system must be coordinated with Liebherr, as well as the installation posi-tion, at the conceptual design stage of the axial piston unit and must be approved by Liebherr.
The factory values set by Liebherr are only preset values:• Readjust the settings on the device or on the system if necessary.• Prevent foaming: Make sure that the lines meet at least 200 mm below the minimum liquid level in the tank in
every installation variant / position.
Design the hydraulic fluid tank so that the hydraulic oil cools off sufficiently during circulation and impurities thatdevelop during operation settle to the bottom of the tank.
Liebherr distinguishes between three installation variants for axial piston units: A, B and C; as well as six installation positions: 1-6.
NoteLiebherr recommends:Lay the leakage oil lines so that they are above the level of the axial piston unit.
NoteLiebherr recommends:Installation variant: Under-the-tank installation AInstallation position: Horizontal driving shaft, regulator on top
Under-the-tank installation "A": Axial piston unit is installed under the minimum liquid level of the tank.Over-the-tank installation "B": Axial piston unit is installed over the minimum liquid level of the tank.
NoteLiebherr recommends: Under-the-tank installation A, so that:- There is hydraulic fluid at suction port S when not operated.- The housing cannot empty to the tank.
1 Baffle To calm the hydraulic fluid in the tank
B DistanceBetween suction port and leakage oil connection
in the tank (the larger the better)
H Max. suction height (only for over-the-tank installation) 750 mm
Tank installation “C”: Axial piston unit is installed below the minimum liquid level in the tank. This tank installationvariant is not permitted for axial piston units with electrical components (e.g. electric
proportional magnet).
1 Baffle To calm the hydraulic fluid in the tank
B DistanceBetween suction port and leakage oil connection
in the tank (the larger the better)
L Leakage oil connections -
MMinimum line end distance
from tank bottom115 mm
S Suction line connection -
T Tank -
NoteLiebherr recommends: For tank installation variant C, the hydraulic product must be ordered and used unpainted. Contact cus-tomer service.
In each of the three installation variants, there are six possible installation locations.
ATTENTIONThe air cushion in the bearing area or on the rotary shaft lip seal “runs hot” in installation positions 1 and 3!Damage of the hydraulic product.Make sure that the following requirements are observed: - Housing is completely filled with hydraulic fluid during commissioning and operation. - Housing is ventilated during commissioning and operation.Check hydraulic fluid level in the housing regularly.
NoteLiebherr recommends: Consult with Liebherr to install a non-return valve with an opening pressure of a maximum of 0.5 bar. Emptying of the axial piston unit is prevented in installation location 3 and installation variant B.
L* Nominal size 108 = 492 mm (without mounting flange)
NoteReady for through drive SAE B/SAE B-B, closed with lid.To use the through drive, the lid must be removed.O-ring to seal axial piston unit 2 is included in scope.
General informationMulti inline axial piston units of 2 or more single units can be supplied on request.
The type code must be filled out separately for each single unit. An abbreviated type designation on an additionalnameplate is used to identify the multi-unit.
The user is not released from the obligation to complete its own evaluations and tests by the information in this datasheet.
An example configuration is illustrated in this data sheet; if not otherwise stated (DPVD 108-108). The product de-livered to you can therefore differ from the figures.
Deviations are likewise possible with data and values in this data sheet; these only serve to select the product con-figuration and are not binding. Unless indicated otherwise, the values stated are for the example configuration(DPVD 108-108). Always use the values from the installation drawing provided.
The warranty and liability terms of the general terms and conditions of Liebherr Machines Bulle SA and Liebherr-Components AG are not extended in scope by the preceding information.