A4VG Variable pumps , Closed circuit pumps , Axial piston variable pump
NV – Version without control module
The mounting surface for the control module is machined and sealed with the standard seal for control modules and a cover plate. This version is ready for retrofitting to control modules (HD, HW, EP, EZ). When used directly for “DA” control and in combinations with “DA” control, the appropriate adjustments must be made to the spring assembly of the adjustment cylinder and control plate.
DG – Hydraulic control, direct operated
With the direct operated hydraulic control (DG), the output flow of the pump is controlled by a hydraulic control pressure, applied directly to the stroking piston through either port X1 or X2.
Flow direction is determined by which control pressure port is pressurized (refer to table below).
Pump displacement is infinitely variable and proportional to the applied control pressure, but is also influenced by system pressure and pump drive speed.
In order to use the optional built-in pressure cut-off, port PS must be used as the control pressure source for the selected control module.
See page 56 for a functional description of the pressure cut-off.
Maximum permissible control pressure: 40 bar
Use of the DG control requires a review of the engine and vehicle parameters to ensure that the pump is set up correctly.
We recommend that all DG applications be reviewed by a Bosch Rexroth application engineer.
If the pump is also equipped with a DA control valve (see page 19), automotive operation is possible for travel drives.
Technical data
Sizes 22 and 28
Nominal pressure 400 bar
Maximum pressure 450 bar
Sizes 71 to 500
Nominal pressure 350 bar
Maximum pressure 400 bar
Features
Integrated auxiliary pump for boost and pilot oil supply
Flow direction changes smoothly when the swashplate is moved through the neutral position
High-pressure relief valves with integrated boost function
With adjustable pressure cut-off as standard
Boost-pressure relief valve
Through drive for mounting of further pumps up to same nominal size
Large variety of controls
Swashplate design
