Drum Propel Motor
Components Of Dram Propel Motor.
(1) Port plate. (2) Piston. (3) Retainer ring. (4) Output shaft. (5) Cylinder block. (6) Spring. (7) Servo piston assembly. (8) Swashplate.
displacement piston motor. The motor uses a two position
servo control to provide two travel speeds.
The hydraulic oil in the main circuit of the propel system flows
in a continuous closed loop from the propel pump. The
direction of the hydraulic oil flow in the circuit, and direction the
motor turns, is determined by the direction the pump
swashplate is tilted from the neutral position (FORWARD or
REVERSE operation). The speed of the motor, in each of two
positions, is determined by the volume of hydraulic oil supplied
by the pump.
Cylinder block (5) is splined to output shaft (4). The end of
cylinder (5) and port plate (1) are high pressure, metal-to-
metal, seal surfaces. Retaining ring (3) is in a groove in the
bore of the cylinder. The force of spring (6) between retainer
ring (3) and the retainer holds the cylinder tight against port
plate (1) and holds the port plate against the motor housing.
Spring pressure also holds the slipper end of pistons (2)
against swashplate (8). There are seven pistons in the motor.
The swashplate is connected by a pin to servo piston assembly
(7) and does not rotate. The two-position servo piston
assembly controls swashplate angle. This motor operates
either at maximum displacement (low speed) or at minimum
displacement (high speed).