Neutral
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| Illustration 1 | g01090106 |
(1) Hydraulic tank relief valve (2) Return line from the bank valve (3) Line (4) Plunger (5) Plunger (6) Plunger (7) Plunger (8) Line (9) Hydraulic tank (10) Pilot control valve (11) Rotating group (12) Check valve (13) Actuator piston (14) Passage (15) Passage (16) Passage (17) Passage (18) Passage (19) Shuttle valve (20) Shuttle valve (21) Parking brake solenoid valve (22) Tow ball valve (23) Left piston motor (24) Shuttle valve (25) Shuttle valve (26) Line (27) Line (28) Oil cooler bypass valve (29) Check valve (30) Passage (31) Servo valve (32) Backup alarm switch (33) Line (34) Backup alarm switch (35) Line (36) Pilot shutoff valve (if equipped) (37) Speed sensing valve (38) Overspeed valve (39) Line (40) Underspeed control valve (41) Low brake pressure switch (42) Rear piston pump (43) Service brake valve (44) Line (45) Gear pump (46) Engine (47) Hydraulic oil cooler (48) Servo valve (49) Servo valve (50) Line (51) Front piston pump (52) Supply line to the bank valve (53) Oil filter (54) Oil filter (55) Check valve (56) Passage (57) Servo valve (58) Right piston motor (59) Line (60) Rotating group (61) Check valve (62) Passage (63) Actuator piston | |
When pilot control valve (10) is in the NEUTRAL position, plunger (4), plunger (5), plunger (6), and plunger (7) are not depressed. Signal oil from line (8) flows through pilot control valve (10) to line (3). The signal oil flows through line (3) back to hydraulic tank (9) .
Since there is no signal pressure in line (26) or in line (33), servo valve (49) remains centered and the swashplate of pump (51) remains at zero angle. Since there is no signal pressure in line (27) or in line (35), servo valve (48) remains centered and the swashplate of pump (42) remains at zero angle. Since the piston pumps are at zero angle, both loops of the hydrostatic system are in a hydraulic lock and the machine does not move.
Forward Travel
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| Illustration 2 | g01090109 |
(1) Hydraulic tank relief valve (2) Return line from the bank valve (3) Line (4) Plunger (5) Plunger (6) Plunger (7) Plunger (8) Line (9) Hydraulic tank (10) Pilot control valve (11) Rotating group (12) Check valve (13) Actuator piston (14) Passage (15) Passage (16) Passage (17) Passage (18) Passage (19) Shuttle valve (20) Shuttle valve (21) Parking brake solenoid valve (22) Tow ball valve (23) Left piston motor (24) Shuttle valve (25) Shuttle valve (26) Line (27) Line (28) Oil cooler bypass valve (29) Check valve (30) Passage (31) Servo valve (32) Backup alarm switch (33) Line (34) Backup alarm switch (35) Line (36) Pilot shutoff valve (37) Speed sensing valve (38) Overspeed valve (39) Line (40) Underspeed control valve (41) Low brake pressure switch (42) Rear piston pump (43) Service brake valve (44) Line (45) Gear pump (46) Engine (47) Hydraulic oil cooler (48) Servo valve (49) Servo valve (50) Line (51) Front piston pump (52) Supply line to the bank valve (53) Oil filter (54) Oil filter (55) Check valve (56) Passage (57) Servo valve (58) Right piston motor (59) Line (60) Rotating group (61) Check valve (62) Passage (63) Actuator piston | |
When pilot control valve (10) is moved to the FORWARD position, plunger (6) is depressed. Signal oil from line (8) through pilot control valve (10) to plunger (6). The signal oil flows from plunger (6) to shuttle valve (25) and to shuttle valve (20) .
The signal oil shifts shuttle valve (25) to the left and the signal oil flows from shuttle valve (25) through line (26) to servo valve (49). The signal oil overcomes the force of the spring and servo valve (49) shifts to the left. As servo valve (49) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (51) through line (44) to piston motor (23). The pressure oil flows through rotating group (11) of piston motor (23) through passage (14) to line (39). The pressure oil flows through line (39) back to piston pump (51) .
The signal oil shifts shuttle valve (20) to the right and the signal oil flows from shuttle valve (20) through line (27) to servo valve (48). The signal oil overcomes the force of the spring and servo valve (48) shifts to the left. As servo valve (48) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (42) through line (59) to piston motor (58). The pressure oil flows through passage (62) to rotating group (60) of piston motor (58). The pressure oil flows through rotating group (60) to line (50). The pressure oil flows through line (50) back to piston pump (42) .
Forward Travel (Right Turn)
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| Illustration 3 | g01090113 |
(1) Hydraulic tank relief valve (2) Return line from the bank valve (3) Line (4) Plunger (5) Plunger (6) Plunger (7) Plunger (8) Line (9) Hydraulic tank (10) Pilot control valve (11) Rotating group (12) Check valve (13) Actuator piston (14) Passage (15) Passage (16) Passage (17) Passage (18) Passage (19) Shuttle valve (20) Shuttle valve (21) Parking brake solenoid valve (22) Tow ball valve (23) Left piston motor (24) Shuttle valve (25) Shuttle valve (26) Line (27) Line (28) Oil cooler bypass valve (29) Check valve (30) Passage (31) Servo valve (32) Backup alarm switch (33) Line (34) Backup alarm switch (35) Line (36) Pilot shutoff valve (37) Speed sensing valve (38) Overspeed valve (39) Line (40) Underspeed control valve (41) Low brake pressure switch (42) Rear piston pump (43) Service brake valve (44) Line (45) Gear pump (46) Engine (47) Hydraulic oil cooler (48) Servo valve (49) Servo valve (50) Line (51) Front piston pump (52) Supply line to the bank valve (53) Oil filter (54) Oil filter (55) Check valve (56) Passage (57) Servo valve (58) Right piston motor (59) Line (60) Rotating group (61) Check valve (62) Passage (63) Actuator piston | |
When pilot control valve (10) is moved to the FORWARD position and to the RIGHT position, plunger (6) is depressed and plunger (7) is depressed. Signal oil from line (8) through pilot control valve (10) to plunger (6) and to plunger (7). The signal oil flows from plunger (6) to shuttle valve (25) and to shuttle valve (20). The signal oil flows from plunger (7) to shuttle valve (24) and to shuttle valve (20) .
The signal oil shifts shuttle valve (25) to the left and the signal oil flows from shuttle valve (25) through line (26) to servo valve (49). The signal oil overcomes the force of the spring and servo valve (49) shifts to the left. As servo valve (49) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (51) through line (44) to piston motor (23). The pressure oil flows through rotating group (11) of piston motor (23) through passage (14) to line (39). The pressure oil flows through line (39) back to piston pump (51). As a result, the left track rotates forward.
The signal oil from plunger (6) and the signal oil from plunger (7) centers shuttle valve (20) and the combined signal oil flows from shuttle valve (20) through line (27) to servo valve (48). The signal oil shifts shuttle valve (24) to the left and the signal oil flows from shuttle valve (24) through line (35) to servo valve (48). Since the force of the signal oil from line (35) is equal to the force of the signal oil in line (27), servo valve (48) remains centered and the swashplate of pump (42) remains at zero angle. Since piston pump (42) is at zero angle, the right drive loop of the hydrostatic system is in a hydraulic lock and the right track does not move.
Forward Travel (Left Turn)
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| Illustration 4 | g01090114 |
(1) Hydraulic tank relief valve (2) Return line from the bank valve (3) Line (4) Plunger (5) Plunger (6) Plunger (7) Plunger (8) Line (9) Hydraulic tank (10) Pilot control valve (11) Rotating group (12) Check valve (13) Actuator piston (14) Passage (15) Passage (16) Passage (17) Passage (18) Passage (19) Shuttle valve (20) Shuttle valve (21) Parking brake solenoid valve (22) Tow ball valve (23) Left piston motor (24) Shuttle valve (25) Shuttle valve (26) Line (27) Line (28) Oil cooler bypass valve (29) Check valve (30) Passage (31) Servo valve (32) Backup alarm switch (33) Line (34) Backup alarm switch (35) Line (36) Pilot shutoff valve (37) Speed sensing valve (38) Overspeed valve (39) Line (40) Underspeed control valve (41) Low brake pressure switch (42) Rear piston pump (43) Service brake valve (44) Line (45) Gear pump (46) Engine (47) Hydraulic oil cooler (48) Servo valve (49) Servo valve (50) Line (51) Front piston pump (52) Supply line to the bank valve (53) Oil filter (54) Oil filter (55) Check valve (56) Passage (57) Servo valve (58) Right piston motor (59) Line (60) Rotating group (61) Check valve (62) Passage (63) Actuator piston | |
When pilot control valve (10) is moved to the FORWARD position and to the LEFT position, plunger (6) is depressed and plunger (5) is depressed. Signal oil from line (8) through pilot control valve (10) to plunger (6) and to plunger (5). The signal oil flows from plunger (6) to shuttle valve (25) and to shuttle valve (20). The signal oil flows from plunger (5) to shuttle valve (19) and to shuttle valve (25) .
The signal oil shifts shuttle valve (20) to the right and the signal oil flows from shuttle valve (20) through line (27) to servo valve (48). The signal oil overcomes the force of the spring and servo valve (48) shifts to the left. As servo valve (48) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (42) through line (59) to piston motor (58). The pressure oil flows through passage (62) to rotating group (60) of piston motor (58). The pressure oil flows through rotating group (60) to line (50). The pressure oil flows through line (50) back to piston pump (51). As a result, the right track rotates forward.
The signal oil from plunger (6) and the signal oil from plunger (5) centers shuttle valve (25) and the combined signal oil flows from shuttle valve (25) through line (26) to servo valve (49). The signal oil shifts shuttle valve (19) to the right and the signal oil flows from shuttle valve (19) through line (33) to servo valve (49). Since the force of the signal oil from line (33) is equal to the force of the signal oil in line (26), servo valve (49) remains centered and the swashplate of pump (51) remains at zero angle. Since piston pump (51) is at zero angle, the left drive loop of the hydrostatic system is in a hydraulic lock and the left track does not move.
Reverse Travel
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| Illustration 5 | g01090112 |
(1) Hydraulic tank relief valve (2) Return line from the bank valve (3) Line (4) Plunger (5) Plunger (6) Plunger (7) Plunger (8) Line (9) Hydraulic tank (10) Pilot control valve (11) Rotating group (12) Check valve (13) Actuator piston (14) Passage (15) Passage (16) Passage (17) Passage (18) Passage (19) Shuttle valve (20) Shuttle valve (21) Parking brake solenoid valve (22) Tow ball valve (23) Left piston motor (24) Shuttle valve (25) Shuttle valve (26) Line (27) Line (28) Oil cooler bypass valve (29) Check valve (30) Passage (31) Servo valve (32) Backup alarm switch (33) Line (34) Backup alarm switch (35) Line (36) Pilot shutoff valve (37) Speed sensing valve (38) Overspeed valve (39) Line (40) Underspeed control valve (41) Low brake pressure switch (42) Rear piston pump (43) Service brake valve (44) Line (45) Gear pump (46) Engine (47) Hydraulic oil cooler (48) Servo valve (49) Servo valve (50) Line (51) Front piston pump (52) Supply line to the bank valve (53) Oil filter (54) Oil filter (55) Check valve (56) Passage (57) Servo valve (58) Right piston motor (59) Line (60) Rotating group (61) Check valve (62) Passage (63) Actuator piston | |
When pilot control valve (10) is moved to the REVERSE position, plunger (4) is depressed. Signal oil from line (8) through pilot control valve (10) to plunger (4). The signal oil flows from plunger (4) to shuttle valve (19) and to shuttle valve (24) .
The signal oil shifts shuttle valve (19) to the left and the signal oil flows from shuttle valve (19) through line (33) to servo valve (49). The signal oil overcomes the force of the spring and servo valve (49) shifts to the right. As servo valve (49) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (51) through line (39) to piston motor (23). The pressure oil flows through passage (14) to rotating group (11) of piston motor (23). The pressure oil flows through rotating group (11) to line (44). The pressure oil flows through line (44) back to piston pump (51) .
The signal oil shifts shuttle valve (24) to the right and the signal oil flows from shuttle valve (24) through line (35) to servo valve (48). The signal oil overcomes the force of the spring and servo valve (48) shifts to the right. As servo valve (48) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (42) through line (50) to piston motor (58). The pressure oil flows through rotating group (60) of piston motor (58) through passage (62) to line (59). The pressure oil flows through line (59) back to piston pump (42) .
The signal oil from plunger (6) and the signal oil from plunger (5) centers shuttle valve (25) and the combined signal oil flows from shuttle valve (25) through line (26) to servo valve (49). The signal oil shifts shuttle valve (19) to the right and the signal oil flows from shuttle valve (19) through line (33) to servo valve (49). Since the force of the signal oil from line (33) is equal to the force of the signal oil in line (26), servo valve (48) remains centered and the swashplate of pump (51) remains at zero angle. Since piston pump (51) is at zero angle, the left drive loop of the hydrostatic system is in a hydraulic lock and the left track does not move.
Reverse Travel (Right Turn)
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| Illustration 6 | g01090115 |
(1) Hydraulic tank relief valve (2) Return line from the bank valve (3) Line (4) Plunger (5) Plunger (6) Plunger (7) Plunger (8) Line (9) Hydraulic tank (10) Pilot control valve (11) Rotating group (12) Check valve (13) Actuator piston (14) Passage (15) Passage (16) Passage (17) Passage (18) Passage (19) Shuttle valve (20) Shuttle valve (21) Parking brake solenoid valve (22) Tow ball valve (23) Left piston motor (24) Shuttle valve (25) Shuttle valve (26) Line (27) Line (28) Oil cooler bypass valve (29) Check valve (30) Passage (31) Servo valve (32) Backup alarm switch (33) Line (34) Backup alarm switch (35) Line (36) Pilot shutoff valve (37) Speed sensing valve (38) Overspeed valve (39) Line (40) Underspeed control valve (41) Low brake pressure switch (42) Rear piston pump (43) Service brake valve (44) Line (45) Gear pump (46) Engine (47) Hydraulic oil cooler (48) Servo valve (49) Servo valve (50) Line (51) Front piston pump (52) Supply line to the bank valve (53) Oil filter (54) Oil filter (55) Check valve (56) Passage (57) Servo valve (58) Right piston motor (59) Line (60) Rotating group (61) Check valve (62) Passage (63) Actuator piston | |
When pilot control valve (10) is moved to the REVERSE position and to the RIGHT position, plunger (4) is depressed and plunger (7) is depressed. Signal oil from line (8) through pilot control valve (10) to plunger (4) and to plunger (7). The signal oil flows from plunger (4) to shuttle valve (19) and to shuttle valve (24). The signal oil flows from plunger (7) to shuttle valve (19) and to shuttle valve (20) .
The signal oil from plunger (4) and the signal oil from plunger (7) centers shuttle valve (24) and the combined signal oil flows from shuttle valve (24) through line (35) to servo valve (48). The signal oil shifts shuttle valve (20) to the left and the signal oil flows from shuttle valve (20) through line (27) to servo valve (48). Since the force of the signal oil from line (35) is equal to the force of the signal oil in line (27), servo valve (48) remains centered and the swashplate of pump (42) remains at zero angle. Since piston pump (42) is at zero angle, the right drive loop of the hydrostatic system is in a hydraulic lock and the right track does not move.
The signal oil shifts shuttle valve (19) to the left and the signal oil flows from shuttle valve (19) through line (33) to servo valve (49). The signal oil overcomes the force of the spring and servo valve (49) shifts to the right. As servo valve (49) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (51) through line (39) to piston motor (23). The pressure oil flows through passage (14) to rotating group (11) of piston motor (23). The pressure oil flows through rotating group (11) to line (44). The pressure oil flows through line (44) back to piston pump (51). As a result, the left track rotates backward.
Reverse Travel (Left Turn)
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| Illustration 7 | g01090116 |
(1) Hydraulic tank relief valve (2) Return line from the bank valve (3) Line (4) Plunger (5) Plunger (6) Plunger (7) Plunger (8) Line (9) Hydraulic tank (10) Pilot control valve (11) Rotating group (12) Check valve (13) Actuator piston (14) Passage (15) Passage (16) Passage (17) Passage (18) Passage (19) Shuttle valve (20) Shuttle valve (21) Parking brake solenoid valve (22) Tow ball valve (23) Left piston motor (24) Shuttle valve (25) Shuttle valve (26) Line (27) Line (28) Oil cooler bypass valve (29) Check valve (30) Passage (31) Servo valve (32) Backup alarm switch (33) Line (34) Backup alarm switch (35) Line (36) Pilot shutoff valve (37) Speed sensing valve (38) Overspeed valve (39) Line (40) Underspeed control valve (41) Low brake pressure switch (42) Rear piston pump (43) Service brake valve (44) Line (45) Gear pump (46) Engine (47) Hydraulic oil cooler (48) Servo valve (49) Servo valve (50) Line (51) Front piston pump (52) Supply line to the bank valve (53) Oil filter (54) Oil filter (55) Check valve (56) Passage (57) Servo valve (58) Right piston motor (59) Line (60) Rotating group (61) Check valve (62) Passage (63) Actuator piston | |
When pilot control valve (10) is moved to the REVERSE position and to the LEFT position, plunger (4) is depressed and plunger (5) is depressed. Signal oil from line (8) through pilot control valve (10) to plunger (4) and to plunger (5). The signal oil flows from plunger (4) to shuttle valve (19) and to shuttle valve (24). The signal oil flows from plunger (5) to shuttle valve (19) and to shuttle valve (25) .
The signal oil shifts shuttle valve (24) to the right and the signal oil flows from shuttle valve (24) through line (35) to servo valve (48). The signal oil overcomes the force of the spring and servo valve (48) shifts to the right. As servo valve (48) shifts, the angle of the swashplate increases and pressure oil flows from piston pump (42) through line (50) to piston motor (58). The pressure oil flows through rotating group (60) of piston motor (58) through passage (62) to line (59). The pressure oil flows through line (59) back to piston pump (42). As a result, the right track rotates backward.
The signal oil from plunger (4) and the signal oil from plunger (5) centers shuttle valve (19) and the combined signal oil flows from shuttle valve (19) through line (33) to servo valve (49). The signal oil shifts shuttle valve (25) to the right and the signal oil flows from shuttle valve (25) through line (26) to servo valve (49). Since the force of the signal oil from line (33) is equal to the force of the signal oil in line (26), servo valve (49) remains centered and the swashplate of pump (51) remains at zero angle. Since piston pump (51) is at zero angle, the left drive loop of the hydrostatic system is in a hydraulic lock and the left track does not move.