Hydraulic Piston Pump Mannesmann Rexroth A4VTG pump

Features
-- Variable axial piston pump of swash plate design for hydrostatic closed circuit transmission
-- Flow is proportional to drive speed and displacement and is infinitely variable
-- Flow increases with the swivel angle of the swash plate from 0 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 to replenish leakage and provide control oil
-- The maximum boost pressure is limited by a built-in boost pressure relief valve

HW:  Hydraulic control, mechanical servo
The positioning cylinder of the pump and therefore the swivel angle is varied in proportion to the movement of the control lever. The pump control is sleeplessly variable. 
Each direction of flow is assigned to one direction of lever movement.

EP:  Electrical control
With proportional solenoids In relation to the preselected current, control pressure is applied to the positioning cylinder of the pump via two proportional solenoids on control device EP. The displacement of the pump is thus steplessly variable. One solenoid is assigned to each direction of flow.

Installation position
The housing must be filled prior to commissioning, and must remain full whenever it is operating.  For extensive information on the installation position, please read our data sheet RE 90270.
Temperature range of the radial seal rings
The following radial seal rings are to be used in relation of the housing temperature:
-40 C ... -25 C NBR radial seal ring necessary (P);
-25 C ... +90 C    NBR radial seal ring standard (P), FPM radial seal ring possible (N);
+90 C ... +115 C FPM radial seal ring necessary (N).

 

Size 71 90

Displacement Variable pump Vg max cm3 71 90
auxilary pump           Vg H      cm3   18,7   25,7
Speed max. speed at Vg max nmax continuous  rpm 3300 3050 limited max. speed 1) nmax limited rpm 3600 3300 intermittent max. speed 2) nmax intermittend rpm 4100 3800 minimum speed nmin rpm 500 500
Flow at nmax Dauer  and Vg max Qmax L/min 234 275
Power at nmax Dauer p = 400 bar Pmax kW 156 183
Torque at Vg max  p = 400 bar Tmax Nm 451 572 (Variable pump without aux. pump) p = 100 bar T Nm 112,8 143
Moment of inertia (about drive axis) J kgm2 0,0072 0,0106