Service Manual
Series 45 J Frame Open Circuit Axial Piston Pumps
520L0607
• Rev AI • Sep 2013
8
The pump receives fluid directly from the reservoir through the inlet line. A screen placed in the inlet
protects the pump from large contaminants. The output of the pump is directed to a PVG-32
multi-section load sensing directional control valve which directs fluid to the actuators in the system.
Fluid returning from the system is cooled by a heat exchanger and cleaned by a filter before returning
to the reservoir.
The speed of the actuators in the system depends on the volume of fluid being provided by the
pump. The operating pressure varies depending on actuator load, but is limited to an adjustable
maximum setting by the PC section of the pump control and by a system relief valve integrated into
the side module of the PVG valve.
The position of the PVG valve sets the demand for flow in the system and communicates this to the
pump control by means of a hydraulic signal (load sense signal). The pump will provide as much flow
to the system as it demands
1
while limiting the maximum pressure. Therefore flow and pressure in the
system are compensated to meet requirements.
1
Full available flow is a function of pump displacement, operating speed, and efficiency. Refer to
Series 45 Axial
Piston Open Circuit Pumps Technical Information,
520L0676
for details.
Introduction (continued)
System Circuit
Pictorial circuit diagram
P104 366E
System pressure
Servo pressure
Actuator pressure
Load sense pressure
Actuator return
Suction / case drain /
system return
Reservoir
Filter
Double-acting cylinder
PVG 32
multi-section
load
sensing
control
valve
Bi-directional
gear motor
Heat exchanger
J Frame Series 45
open circuit axial
piston pump with
load sensing control
