Sauer Danfoss 40 Series - Hydraulic Displacement Control (HDC) M46 Variable Pump; Features; Benefits

45
520L0635 • Rev EH • June 2009
Series 40 Axial Piston Pumps
Technical Information
Control options
The Hydraulic Displacement Control (HDC) is a two stage design which uses a hydraulic
input signal to operate a spring centered 4-way servo valve, which ports hydraulic
pressure to either side of a double acting servo piston. The servo pis ton tilts the cradle
swashplate, thus varying the pump’s displace ment from full displacement in one
direction to full dis placement in the opposite direc tion.
The HDC provides output ow in proportion to a hydraulic command signal. This allows
for remote control of the machine with a hydraulic pressure source rather than with
mechani cal linkage. With no command signal, the control returns to neutral position.
Features
• The hydraulic displacement control is a high gain control: with only a small change in
the input signal pressure level, the servo valve moves to a full open position, porting
maximum ow to the servo cylinder.
• Internal mechanical stops on the servo valve allow rapid changes in input signal
pressure without damaging the control mechanism.
• Precision parts provide repeatable, accurate dis placement settings with a given
input signal.
• Both ends of the double-acting servo piston are drained to case when input signal
HYDRAULIC
DISPLACEMENT
CONTROL (HDC) M46
VARIABLE PUMP
Port X2
Port X1
P100 599E
B
M2
M1
A
E
L1
L2
M5
M4
S
M3
X2
X1
P104 367
HDC on M46 PV
HDC Hydraulic Schematic
pressure is not present. The servo
piston is coupled to a spring
centering mechanism.
Benefits
• Simple, low-cost design.
• Pump will return to neutral after
prime mover shuts down.
• Pump will return to neutral if
external hydraulic input signal fails
or if there is a loss of charge pres sure.