TM 5-3895-382-24
Propel Pumps
Propel Pumps.
(1) Swashplate. (2) Barrel assembly. (3) Port plate. (4) Pistons. (5) Housing. (6) Shaft. (7) Bearing sleeve. (8) Link pin. (9) Rotating group (10)
Spring. (11) Servo control spool. (12) Control sleeve. (13) Servo piston.
When the engine is running, shaft (6) and barrel assembly (2)
are rotating. There are seven pistons (4) in the barrel
assembly. Port plate (3) and swashplate (1) are fastened to or
held by housing (5) and do not rotate. Spring (10) keeps a
force on the barrel assembly to make a high pressure seal
between the barrel assembly and the port plate. When the
barrel assembly is rotating, each piston (4) follows the angle of
the swashplate. If the swashplate angle is at zero, the pistons
do not move in and out of the barrel assembly, and there is no
oil flow. Charge oil from the steering system maintains oil
pressure in the propel pump to keep the barrel assembly full of
oil. The charge oil is also used to fill the closed loop system
with oil. This pressure provides the service braking for the
system.
The position of the swashplate is controlled by servo control
spool (11) and servo piston (13). Movement of the propel
control lever moves the servo control spool. The spool routes
charge oil to activate and adjust the servo piston. As the
swashplate moves, it controls the movement of link pin (8)
which allows bearing sleeve (7) to cover the port on control
sleeve (12). This controls the amount of stroke for the pump.
The servo piston controls the direction and amount of
swashplate angle.
Oil flows from the propel pump to the propel motor and back to
the pump through the inlet and outlet ports. The position of the
swashplate determines the direction of flow and which of the
two loop lines is the high pressure line.
11-8
