Brueninghaus Hydromatik Rexroth A4VTG pump
Concrete mixer hydraulic piston pump A4VTG71, A4VGT90
Sizes 71, 90
Nominal pressure 5800 psi (400 bar)
Maximum pressure 6500 psi (450 bar)
Control device: (HW) Proportional control hydraulic, mechanical servo, hexagon shaft with lever to the rear.
(EP) Proportional control electric, with emergency actuation and spring return.
For the drum drive in mobile concrete mixers A4VTG071, A4VGT090 series.
–Variable axial piston pump of swash plate design for hydrostatic drives in closed circuit
–The flow is proportional to the drive speed and displacement.
–The flow increases as the angle of the swash plate is adjusted from zero to its maximum value.
–Flow direction changes smoothly when the swash plate is moved through the neutral position.
–Two pressure-relief valves are provided on the high pressure ports to protect the hydrostatic transmission (pump and motor) from overload.
–The high-pressure relief valves also function as boost valves.
–The integrated boost pump acts as a feed pump and control pressure supply.
–The maximum boost pressure is limited by a built-in boost pressure-relief valve.
–Tapered shaft option for direct drive shaft yoke installation.
Table of values (theoretical values, without efficiency and tolerances; values rounded)
|Variable pump||Vg max||cm3||71||90|
|auxiliary pump||Vg H||cm3||18,7||25,7|
|Max. speed at Vg max||Nmax continuous||rpm||3300||3050|
|Limited max.||Nmax limited||rpm||3600||3300|
|Intermittent max.||Nmax continuous||rpm||4100||3800|
|Flow||at Nmax Dauer and Vg max||Qmax||L/min||234||275|
|Power||at Nmax Dauer D p = 400 bar||Pmax||kW||156||183|
|Torque||at Vg max D p = 400 bar||Tmax||Nm||451||572|
|(Variable pump without aux. pump) D p = 100 bar||T||Nm||112,8||143|
|Moment of inertia (about drive axis)||J||kgm2||0,0072||0,0106|
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 variable pump A4VTG is not suitable for operation with HFA, HFB and HFC. If HFD or environmentally acceptable hydraulic fluids are being used, the limitations regarding technical data and seals must be observed.
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 (νopt), 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 °F (X °C), an operating temperature of 140 °F (60 °C) is set in the circuit. In the optimum operating viscosity range (νopt shaded area), this corresponds to the viscosity classes VG 46 or VG 68; to be selected: VG 68. 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 than 240 °F (115 °C), however. The temperature difference specified below is to be taken into account when determining the viscosity in the bearing.
Shaft seal ring
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 45 psi (3 bar) absolute at operating temperature not be exceeded (maximum permissible case drain pressure 90 psi (6 bar) absolute at reduced speed, see diagram). Short-term (t < 0.1 s) pressure spikes of up to 145 psi (10 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.
Control device HW – Proportional control hydraulic, mechanical servo
The output flow of the pump can be steplessly varied in the range between 0 to 100 %, proportional to the rotation of the control lever between 0° and ±29°. A feedback lever connected to the stroke piston maintains the pump flow for any given position of the control lever between 0° and 29°.
The maximum required torque at the lever is 15 lb-in (170 Ncm). To prevent damage to the HW control unit, a positive mechanical stop must be provided for the HW control lever.
Control device EP – Proportional control electric
The output flow of the pump can be steplessly varied in the range between 0 to 100 %, proportional to the electrical current supplied to solenoid a or b.
The electrical energy is converted into force acting on the control piston. This control piston then directs control hydraulic fluid into and out of the stroke cylinder to adjust pump displacement as required.
A feedback lever connected to the stroke piston maintains the pump flow for any given current within the control range.
|Details model of Rexroth A4VTG71 & Rexroth A4VTG90 pump|
|R902132673 A4VTG071HW100/33MLNC4C82F0000AS-0||R902069484 A4VTG90EP2/32L-NZD10N001EW-S|
|R902132671 A4VTG071HW100/33MRNC4C82F0000AS-0||R902071852 A4VTG71EP2/32R-NLD10F001ST-S|
|R902155546 A4VTG090HW100/33MRNC4C92F0000AS-0||R902072877 A4VTG90EP2/32R-NSD10F011ST-S|
|R902155618 A4VTG090HW100/33MRNC4C92F0000AS-0||R902072914 A4VTG71EP2/32L-NSD10F001SX-S|
|R902155547 A4VTG090HW100/33MLNC4C92F0000AS-0||R902074155 A4VTG71EP1/32R-NLD10F001SGT-S|
|R902061570 A4VTG90EZ1/32L-NSD10F071SH-S||R902074168 A4VTG71HW/32R-NSD10F011S|
|R902061572 A4VTG71EZ1/32L-NXD10F071SH-S||R902074373 A4VTG71EP1/32R-NSD10F001ST-S|
|R902061573 A4VTG71EZ1/32L-NXD10F001SH-S||R902074403 A4VTG90EP2/32R-NLD10F011ST-S|
|R902062961 A4VTG90EP1/32L-NZD10K021EW-S||R902074406 A4VTG90EP2/32L-NLD10F001ST-S|
|R902085645 A4VTG90EZ1/32L-NZD10F021SH-S||R902074408 A4VTG90EP2/32R-NSD10F011SGT-S|
|R902064251 A4VTG71EP2/32L-NXD10F001SH-S||R902077977 A4VTG71HW/32R-NLD10F021S-K|
|R902084560 A4VTG71EP2/32L-NZD10K021EP-S||R902079554 A4VTG71EP2/32L-NXD10F021SH-S|
|R902064721 A4VTG71EP2/32R-NLD10F001SGT-S||R902079556 A4VTG71EP1/32R-NLD10F001ST-S|
|R902064723 A4VTG90EP2/32R-NLD10F001SGT-S||R902079583 A4VTG90HW/32R-NSD10F001S-S|
|R902066191 A4VTG90HW/32L-NSD10F001S-S||R902079590 A4VTG71EP2/32L-NZD10K021EP-S|
|R902066730 A4VTG90EP2/32R-NLD10F011SGT-S||R902079597 A4VTG71EP2/32L-NZD10K021EP-SK|
|R902066731 A4VTG90EP2/32L-NLD10F011SGT-S||R902079762 A4VTG71EP2/32R-NSD10F011ST-S|
|R902066732 A4VTG71EP2/32L-NLD10FXX1SGT-S||R902079857 A4VTG90EP2/32L-NLD10F011ST-S|
|R902068067 A4VTG90EZ1/32L-NZD10F011SH-S||R902079888 A4VTG90HW/32R-NLD10F001S|
|R902068087 A4VTG90EZ1/32L-NSD10FXX1SH-S||R902079961 A4VTG71HW/32R-NLD10F001S|
|R902068090 A4VTG90EP2/32R-NLD10F001ST-S||R902081370 A4VTG90EP2/32R-NSD10F001ST-S|
|R902068121 A4VTG90HW/32L-NLD10F001S||R902083530 A4VTG90HW/32L-NLD10F001S|
|R902068451 A4VTG71EP2/32L-NSD10F001SW-S||R902083968 A4VTG71EP2/32L-NZD10K021EP-S|