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| Illustration 1 | g00887063 |
Front Propel Motor (1) Shuttle Valve (2) Main Loop Port (3) Case Drain (4) Rotating Group (5) Piston (6) Output Shaft (7) Forward/Reverse Charge Relief Valve (8) Control Valve (9) Swashplate | |
The propel motor is an axial piston motor. Also, the propel motor is a variable displacement motor. The following components are in the head of the propel motor: main circuit ports (2), shuttle valve (1) and forward/reverse charge relief valve (7).
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| Illustration 2 | g00900805 |
Schematic of the Front Propel Motor (1) Shuttle Valve (2) Main circuit ports (7) Forward/Reverse Charge Relief Valve (8) Control Valve (10) Servo Oil Line | |
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| Illustration 3 | g00887066 |
Cross Section of the Swashplate (5) Pistons (9) Swashplate (12) Servo Piston (13) Servo Piston | |
Pressurized oil enters one of main circuit ports (2), depending on the desired direction and the desired speed of the machine movement. The volume of the oil is dependent on the RPM and on the angle of the swashplate on the propel pump. The angle of swashplates (9) determines the RPM of output shaft (6) in the propel motor. The oil goes to pistons (5) and to rotating group (4) which causes a rotating force in output shaft (6) .
The output RPM of the propel motor is partially determined by the angle of swashplate (9). Solenoid (8) is energized when the transmission control switch is in position 2 or in position 4. Oil flows through one of specific servo oil line (10) to servo piston (21). The oil rotates swashplate (9) against a minimum displacement screw. When the angle is decreased, pistons (5) are reduced to a minimum stroke and the output RPM of the propel motor increases. Oil then flows out of the propel motor through the opposite main circuit port (2) and back to the propel pump.
To decrease the output RPM of the propel motor, de-energize solenoid (8) by placing the transmission control switch in position 1 or in position 3. Oil flows through one servo oil line (10) to servo piston (13). Servo piston (13) rotates swashplate (9) to a maximum displacement screw. This rotation increases the angle of swashplate (9). The stroke of pistons (5) increases as the angle increases. The output RPM of output shaft (6) decreases while the torque of output shaft (6) increases. The oil flows out of the propel motor through main circuit port (2) and returns to the propel pump.