A4VG Hydraulic Axial Piston Pump

Product Description

The A4VG axial piston variable pump in swash plate design for hydrostatic closed circuit transmissions.Hydraulic variable displacement axial pump A4VG40, A4VG56, A4VG71, A4VG90, A4VG125, A4VG180, A4VG250.

The A4VG axial piston variable pump in swash plate design for hydrostatic closed circuit transmissions

– Flow is proportional to drive speed and displacement and is infinitely variable

– Output 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

– A wide range of highly adaptable control devices is available for different control and regulating functions

– The pump is equipped with two pressure-relief valves 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 and control oil pump

– The maximum boost pressure is limited by a built-in boost pressure relief valve

– The integral pressure cut-off is standard

Technical Parameter

Feature

HD – proportional control, hydraulic, pilot-pressure related  

Depending on the pressure difference of the pilot pressure pSt in the two control lines (ports Y1 and Y2), the stroke cylinder of the pump is supplied with control pressure via the HD control unit. Thus, the swash plate – and, therefore, the displacement – are infinitely adjustable. A different flow direction is associated with each control line.

HW – proportional control, hydraulic, mechanical servo

Depending on the swivel angle of the control lever and the actuating direction, the stroke cylinder of the pump is supplied with control pressure via the HW control unit. Thus, the swash plate – and, therefore, the displacement – are infinitely adjustable. A different actuating direction is associated with each direction of control lever actuation.

EP – proportional control, electric

Depending on the preselected current “I” at the two proportional solenoids, the stroke cylinder of the pump is supplied with control pressure via the EP controller. Thus, the swash plate – and, therefore, the displacement – are infinitely adjustable. A different flow direction is associated with each proportional solenoid.

DA – automatic control, hydraulic, speed related  

Depending on the drive speed, the DA control unit generates a pilot pressure which charges the stroke cylinder of the pump with control pressure via a 4/3-directional valve, allowing the swash plate – and, therefore, the displacement – to be infinitely adjusted. Each flow direction is assigned a switching solenoid on the 4/3-directional valve. You can find details on DA closed loop control in operating instructions Hydrostatic travel drive with DA closed loop control” – RE 90 330-01-B and in RE 90 330-03-B (functional description and project planning notes).