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Hydraulic Transmission Piston Pump A4VTG
Hydraulic Transmission Piston Pump A4VTG
Hydraulic Transmission Piston Pump A4VTG
Hydraulic Transmission Piston Pump A4VTG
Hydraulic Transmission Piston Pump A4VTG
Hydraulic Transmission Piston Pump A4VTG
  1. Hydraulic Transmission Piston Pump A4VTG
  2. Hydraulic Transmission Piston Pump A4VTG
  3. Hydraulic Transmission Piston Pump A4VTG
  4. Hydraulic Transmission Piston Pump A4VTG
  5. Hydraulic Transmission Piston Pump A4VTG
  6. Hydraulic Transmission Piston Pump A4VTG

Hydraulic Transmission Piston Pump A4VTG

1.Integrated auxliay pump for boost and piot oilsupply.

2.Flow direcion changes smoothy when the swashplate is moved through the neutral postion

3.High-pressure relief valves with integated boost function.

4.With adjustable pressure cut-off as standard

5.Boost-pressure relief valve

6.Through drive for mounting of further pumps up to same nominal size

Detailed description

This hydraulic pump is designed with multiple practical functions to ensure stable and efficient operation in various hydraulic systems. It is equipped with an integrated auxiliary pump dedicated to providing stable boost and pilot oil supply, which guarantees sufficient oil pressure for the system’s control components and effectively prevents cavitation. When the swashplate moves through the neutral position, the pump’s flow direction changes smoothly without obvious pressure fluctuations or mechanical impact, reducing internal wear and prolonging service life. It is configured with high-pressure relief valves with integrated boost function and a dedicated boost-pressure relief valve, which jointly protect the system from overpressure damage and maintain stable boost pressure. As a standard configuration, it comes with an adjustable pressure cut-off function, allowing users to flexibly set the cut-off pressure according to actual working needs. Additionally, it features a through drive design that enables the mounting of further pumps up to the same nominal size, expanding the system’s hydraulic output capacity and enhancing application versatility.

Ordering code for standard program

A4VT G / 33 M N C4 F A S
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18

Axial piston unit

01 Swashplate design, variable, nominal pressure 400 bar, maximum pressure 450 bar, mobile concrete mixers A4VT

Operating mode

02 Pump, closed circuit G

Size

03 Displacement Vg max in cm3 071 090

Control device

071 090
04 Proportional control hydraulic, mechanical servo, hexagon shaft with lever to the rear ● ● HW11)
Proportional control electric,

with emergency actuation and spring return

 U=12VDC ● ● EP3
U=24 VDC ● ● EP4

Connector for solenoids2)

071 090
05 Without ● ● 0
DEUTSCH - molded connector, 2-pin - without suppressor diode ● ● P

Auxiliary functions

071 090
06 Without ● ● 0
With mechanical stroke limiter, externally adjustable ● ● M
With ports X3, X4 for stroking chamber pressure ● ● T
With mechanical stroke limiter and ports X3, X4 ● ● B

Series

07 Series 3, Index 3 33

Version of port and fixing threads

08 Metric M

Direction of rotation

09 Viewed from drive shaft clockwise R
anti-clockwise L

Seals

10 NBR (nitrile-caoutchouc), shaft seal ring in FKM (fluor-caoutchouc) N

Mounting flange

11 SAEJ744, 127-4 C4

Drive shaft

071 090
12 Splined shaft

ANSIB92.1a-1976

 1 3/8 in 21T 16/32DP without coupling flange ● - V8
with coupling flange ● - C8
1 1/2 in 23T 16/32DP without coupling flange - ● V9
with coupling flange - ● C9

Service line ports

071 090
13 SAE flange port

A and B on same side

 left Suction port S at bottom ○ ○ 1
right Suction port S at top ● ● 2

•= available   ○= on request   -= not available

1)Mounting position of the lever not specified on delivery, to be aligned by the customer

2) Connectors for other electric components can deviate.

Boost pump

14 With integrated boost pump F

Through drive

15 Flange SAE J744 Coupling for splined shaft1)
Mounting variant
Diameter Symbol Designation Diameter Designation 071 090
Without ● ● 0000
82-2 A2 5/8 in 9T 16/32DP S2 ● ● A2S2
101-2 B2 7/8 in 13T 16/32DP S4 ● ● B2S4

High-pressure valves

16 With high-pressure relief valve, direct controlled A

Filtration boost circuit

17 Filtration in the boost pump suction line S

Standard / special version

12 Standard version -0
combined with attachment part or attachment pump -K
Special version -S
combined with attachment part or attachment pump -T

Note

Short designation X refers to a special version not covered by the ordering code.

•= available   ○= on request   -= not available

3) Coupling for splined shaft acc. ANSI B92.1a-1976

Technical data

Hydraulic fluid

Before starting project planning, please refer to our data sheets RE 90220 (mineral oil) and RE 90221 (environmentally acceptable hydraulic fluids) for detailed information regarding the choice of hydraulic fluids and application conditions.

The A4VTG variable pump is not suitable for operation with HFA, HFB and HFC. If HFD or environmentally acceptable hy-draulic fluids are being used, the limitations regarding technical data and seals must be observed.Please contact us.

When ordering, indicate the hydraulic fluid that is to be used.

Selection diagram

Details regarding the choice of hydraulic fluid

The correct choice of hydraulic fluid requires knowledge of the operating temperature in relation to the ambient temperature: in a closed circuit the circuit temperature.

The hydraulic fluid should be chosen so that the operating viscosity in the operating temperature range is within the optimum range (vopt), see shaded area of the selection diagram. We recommended that the higher viscosity class be selected in each case.

Example: At an ambient temperature of X °C, an operating temperature of 60 °C is set in the circuit. In the optimum operating viscosity range (vopt.shaded area), this corresponds to the viscosity classes VG 46 or VG 68; to be selected: VG 68.

Note

The case drain temperature, which is affected by pressure and speed, is always higher than the circuit temperature. At no point of the component may the temperature be higher than115 °C, however. The temperature difference specified below is to be taken into account when determining the viscosity in the bearing.

If the above conditions cannot be maintained due to extreme operating parameters, please contact us.

Viscosity and temperature

Viscosity [mm2/s] Temperature Comment
Storage Tmin ≥ -50 °C up to 12 months with standard factory conservation
Topt = +5 °C to +20 °C up to 24 months with long-term factory conservation
(Cold) start-up1)

Permissible tempera-

ture difference

 Vmax=1600 TSt≥ -40°C t≤3 min, without load (p≤50 bar), n ≤ 1000 rpm
ΔT≤25K between axial piston unit and hydraulic fluid
Warm-up phase v<1600to400 T=-40 °C to-25°C at Pnom,0.5·nnom and t ≤ 15 min
Operating phase

Temperature

difference

 ΔT=approx.5 K The temperature of the hydraulic fluid in the bearing is (depending on pressure and speed) approx. 5 K higher than that of the case drain fluid at port T.
Continuous operation v=400 to 10

Vopt=16 to 36

 T=-25°C to +90 °C no restriction within the permissible data
Short-term operation Vmin=<10to5 Tmax = +115 °C t<3 min,p<0.3·Pnom
Shaft seal ring FKM1) T≤ +115°C see page 5

1)At temperatures below -25 °C, an NBR shaft seal ring is required

(permissible temperature range: -40 °C to +90 °C)

Filtration of the hydraulic fluid

Filtration improves the cleanliness level of the hydraulic fluid,which, in turn, increases the service life of the axial piston unit.

To ensure the functional reliability of the axial piston unit, a gravimetric evaluation is necessary for the hydraulic fluid to determine the amount of contamination by solid matter and to determine the cleanliness level according to ISO 4406. A cleanliness level of at least 20/18/15 is to be maintained.

Depending on the system and the application, for the A4VTG,we recommend

Filter cartridges β20 > 100.

With an increasing differential pressure at the filter cartridges,the B-value must not deteriorate.

At very high hydraulic fluid temperatures (90 °C to maximum 115 °C), a cleanliness level of at least 19/17/14 according to ISO 4406 is necessary.

If the above classes cannot be achieved, please contact us.

For notes on filtration types, see page 16.

Shaft seal ring

Permissible pressure loading

The service life of the shaft seal ring is affected by the speed of the pump and the case drain pressure. It is recommended that the average, continuous case drain pressure 3 bar absolute at operating temperature not be exceeded (maximum permissible case drain pressure 6 bar absolute at reduced speed,see diagram). Short-term (t <0.1 s) pressure spikes of up to10 bar absolute are permitted. The service life of the shaft seal ring decreases with an increase in the frequency of pressure spikes.

The case pressure must be equal to or greater than the external pressure on the shaft seal ring.

Temperature range

The FKM shaft seal ring may be used for case drain temperatures from-25 °C to +115 °C.

 Note

For application cases below -25 °C, an NBR shaft seal ring is necessary (permissible temperature range: -40 °C to +90 °C).

State NBR shaft seal ring in plain text when ordering.

Please contact us.

Operating pressure range

Pressure at service line port A or B

Nominal pressure pnom----------- 400 bar absolute

Maximum pressure Pmax----------- 450 bar absolute

Single operating period-------------- 10s

Total operating period-------------- 300h

Minimum pressure (high-pressure side)------------ 25 bar

Minimum pressure (inlet)--------------10 bar(boost pressure setting must be higher depending on system)

Rate of pressure change RA max------------ 9000 bar/s

Boost pump

Pressure at suction port S

Duration ps min (v ≤ 30 mm2/s)--------------≥ 0.8 bar absolute

at cold starts, short-term (t <3 min) -------------≥ 0.5 bar absolute

Maximum ps max----------------≤5 bar absolute

Standard adjustment pSp (at n= 1500 rpm)------------ 22 bar

Nominal pressure pSp nom--------------- 30 bar

Maximum pressure pSp max--------------- 0 bar

Control pressure

To ensure the function of the control, the following control pressure is required depending on the speed and operating pressure (measurement point, port Ps):

For controls EP and HW

Minimum control pressure PSt min (at n = 1500 rpm)--- 22 bar

Definition

Nominal pressure Pnom

The nominal pressure corresponds to the maximum design pressure.

Maximum pressure pmax

The maximum pressure corresponds the maximum operating pressure within the single operating period. The sum of the single operating period must not exceed the total operating period.

Minimum pressure (high-pressure side)

Minimum pressure on the high-pressure side (A or B) that is required in order to prevent damage to the axial piston unit.

Minimum pressure (inlet)

Minimum pressure in inlet (A or B) that is required in order to prevent damage to the axial piston unit.

Rate of pressure change RA

Maximum permissible rate of pressure build-up and pressure reduction during a pressure change over the entire pressure range.

Table of values (theoretical values, without efficiency levels and tolerances; values rounded)

Size NG 71 90
Displacement variable pump Vg max cm3 70 90
boost pump (at p = 20 bar) Vg Sp cm3 20.5 27
Speed at Vg max nnom rpm 3300 3050
minimum nmin rpm 500 500
Flow at nnom H and Vg max qv max I/min 234 275
Power1) at nnom H, Vg max Δp = 400 bar Pmax kW 156 183
Torque1) at Vg max and Δp = 400 bar Tmax Nm 452 573
Δp = 100 bar T Nm 113 143
Rotary stiffness drive shaft V8 c Nm/rad 120900 -
drive shaft V9 c Nm/rad - 150896
Moment of inertia for rotary group JGR Kgm2 0.0097 0.0149
Maximum angular acceleration2) α rad/s2 21000 18000
Filling capacity V L 1.3 1.2
Mass approx. (without through drive) m kg 51 53

1)Without boost pump

2) The area of validity lies between the minimum required and maximum permissible speed.

It applies for external stimuli (e. g. engine 2 to 8 times rotary frequency, cardan shaft twice the rotary frequency).

The limit value applies for a single pump only.

The load capacity of the connection parts must be considered.

Note

Operation above the maximum values or below the minimum values may result in a loss of function, a reduced service life or in the destruction of the axial piston unit. We recommend testing the loads by means of experiment or calculation/simulation and comparison with the permissible values.

Determining the operating characteristics

Flow qv=(Vg ∙ n ∙ ηv) / 1000 I/min
Torque T=(Vg ∙ Δp) /(20 ∙ π ∙ ηhm) Nm
Power P=(2π ∙ T ∙ n)/60000=(qv ∙ Δp)/(600 ∙ ηt)  kW

Vg = Displacement per revolution in cm3

Δp = Differential pressure in bar

n = Speed in rpm

ηv = Volumetric efficiency

ηmh = Mechanical-hydraulic efficiency

ηt = Overall efficiency (ηt= ηv* ηmh)

Permissible radial and axial loading on drive shaft

Size NG 71 90
Drive shaft in 1 3/8 1 1/2
Radial force maximum

at distance a

(from shaft collar)

 Fq max

a

 N

mm

 5600

24

 7100

24
Axial force maximum +Fax max N 4242 4330
-Fax max N 2758 2670

Note

Special requirements apply in the case of belt drives. Please contact us.

Force-transfer direction of the permissible axial force:

+ Fax max=Increase in service life of bearings

- Fax max=Reduction in service life of bearings (avoid)

Permissible input and through-drive torques

Size NG 71 90
Torque at Vg max and Δp= 400 bar)1) Tmax Nm 452 573
Input torque

at drive shaft, maximum2)

 V8 Nm TEmax Nm 970 -
V9 Nm TEmax Nm - 1305
Maximum through-drive torque TDmax Nm 250 250

1)Efficiency not considered

2) For drive shafts with no radial force