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| Illustration 1 | g01392654 |
Each propulsion motor is a piston type motor with two speeds. A propulsion motor drives each track through a single speed planetary final drive. The ports on the motors are marked for identification. On the right motor, port "A" is the reverse port and port "B" is the forward port. On the left motor, port "A" is the forward port and port "B" is the reverse port. Port "M3" on both motors is the shift port.
Each motor is equipped with a speed sensor. A gear on the output shaft of the motor rotates past the tip of the speed sensor. Each time a tooth passes the sensor, an electrical impulse is sent to the machine ECM. The machine ECM converts the frequency of the electrical impulses to a vehicle speed.
Each propulsion motor contains a flushing valve. Flushing valves direct oil from the low pressure side of the propulsion loop to the flushing relief valve. The flushing relief valves open when the pressure in the low pressure side of the propulsion loop is greater than the flushing relief pressure setting. Each flushing relief valve directs a metered amount of oil from the low pressure side of the loop into the motor case drain. The case drain line on each motor directs oil from the motor cases to the cooler bypass manifold.
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| Illustration 2 | g01392677 |
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Propulsion Motor Cross Section (5) Minimum displacement screw (6) Case drain (7) Output shaft (8) Synchronizing shaft (9) Speed sensor (10) Piston (11) Maximum displacement limiter (12) From shift solenoid (13) Flushing relief valve (14) Flushing spool (15) Feedback linkage (16) Servo piston (17) Valve segment (18) Cylinder block | |
The right propulsion motor and left propulsion motor are identical. Each propulsion motor is a piston type motor with two speeds. The motor contains a loop flushing valve.
The shift solenoid on the auxiliary manifold determines the speed range of the motor. The motor is internally pilot operated. This will keep pressure against the servo piston in order to effect the low motor speed.
The feedback linkage attaches to the center of the servo piston. As the servo piston shifts down, the feedback linkage shifts down. One end of the feedback linkage is attached to the valve segment. As the servo piston and the feedback linkage shift down, the valve segment also shifts down. The servo piston and the valve segment continue moving until the servo piston contacts the maximum displacement limiter. When the servo piston contacts the maximum displacement limiter, the motor is at maximum displacement. This position corresponds to low speed and maximum torque of the motor.
Supply oil from the propulsion pump in the high pressure circuit enters the piston cavity in the cylinder block. The pump supply oil forces the pistons to move out of the piston chamber. This causes the cylinder block to rotate. The synchronizing shaft transfers the rotation of the cylinder block to the motor output shaft. The output shaft transmits power to the final drive assembly.
High pressure oil acts against one side of the flushing spool and low pressure oil acts against the other side of the flushing spool. The force from the high pressure oil causes the flushing spool to shift. The shift opens a passage for oil in the low pressure circuit in order to act against the flushing relief valve. The flushing relief valve opens. This allows oil in the low pressure circuit to flow into the motor case drain.