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| Illustration 1 | g03415631 |
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Hydraulic schematic for STICK OUT operation (1) Line (2) Stick cylinder (3) Line (4) Pilot line (5) Line (6) Passage (7) Passage (8) Pilot line (9) Stick I control valve (10) Implement pressure switch (11) Line (12) Main control valve (13) Pilot line (14) Passage (15) Passage (16) Stick drift reduction valve (17) Passage (18) Center bypass passage (19) Passage (20) Load check valve (21) Passage (22) Stick regeneration valve (23) Parallel feeder passage (24) Center bypass passage (25) Passage (26) Line relief valve (rod end) (27) Line relief valve (head end) (28) Valve (29) Return passage (30) Passage (31) Stick unloading valve (32) Passage (33) Check valve (34) Passage (35) Parallel feeder passage (36) Stick II control valve (37) Passage (38) Check valve (39) Line (40) Passage (41) Return passage (42) Passage (43) Passage (NFC signal) (44) Line (45) Check valve (46) Passage (47) Line (48) Pressure reducing valve for boom priority (49) Pilot control valve (stick and swing) (50) Line (51) Return line (52) Idler pump (53) Pilot pump (54) Drive pump | |
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| Illustration 2 | g03416985 |
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STICK OUT operation (1) Line (2) Stick cylinder (3) Line (7) Passage (8) Pilot line (9) Stick I control valve (13) Pilot line (15) Passage (16) Stick drift reduction valve (17) Passage (18) Center bypass passage (19) Passage (20) Load check valve (21) Passage (28) Valve (30) Passage (36) Stick II control valve (37) Passage (38) Check valve (39) Line (40) Passage (42) Passage (43) Passage (NFC signal) (44) Line | |
When the stick hydraulic circuit is operated independently of other hydraulic circuits, stick I control valve (9) and stick II control valve (36) are operational for both the STICK IN and STICK OUT operations. When stick I control valve (9) and stick II control valve (36) are operated, the oil delivery from drive pump (54) and idler pump (52) are combined. The oil delivery from both pumps flows to stick cylinder (2) in order to perform a stick operation.
The oil delivery from drive pump (54) flows through parallel feeder passage (35) in main control valve (12) to stick II control valve (36). The oil delivery from idler pump (52) flows through parallel feeder passage (23) in main control valve (12) to stick I control valve (9).
When stick I control valve (9) is shifted down, pilot oil is blocked at the stick I control valve (9). Pilot oil pressure to implement pressure switch (10) increases. The increase of pilot pressure activates implement pressure switch (10). Implement pressure switch (10) sends an electrical signal to the machine ECM. Implement pressure switch (10) information is used to control engine speed and pump control. Also, an electrical signal from the machine ECM energizes the swing brake solenoid valve in order to release the swing parking brake.
The pilot oil flows from pilot control valve (49), through pilot line (4), and divides into two flow paths. Part of the pilot oil flows through pilot line (8) to stick I control valve (9). The remainder of the pilot oil flows through pilot line (13) to stick II control valve (36).
The pilot oil in pilot line (8) shifts the spool of stick I control valve (9) down. The oil delivery from idler pump (52) that is in parallel feeder passage (23) flows through passage (21), through load check valve (20), and to stick I control valve (9). The oil then flows through passage (17) and enters stick drift reduction valve (16). Stick drift reduction valve (16) shifts downward and the oil delivery flows through passage (14), and into line (3). The oil then flows into the rod end of stick cylinder (2).
The pilot oil in pilot line (13) shifts the spool of stick II control valve (36). The oil delivery from drive pump (54) cannot flow through stick II control valve (36) to passage (43). Part of the oil delivery from drive pump (54) flows through center bypass passage (24), through check valve (45), and into passage (37). The hydraulic oil then flows through stick II control valve (36) and into passage (40). The remainder of the oil delivery from drive pump (54) flows through parallel feeder passage (35). The oil then flows through check valve (38) and stick II control valve (36) to passage (40). All of the oil delivery from drive pump (54) in passage (40) flows to stick drift reduction valve (16) and combines with the oil delivery from idler pump (52). The combined pump oil flows to the rod end of stick cylinder (2). This combined pump oil causes the cylinder to retract at an increased rate of speed.
Return oil from the head end of stick cylinder (2) flows through line (1) and through passage (15). Return oil then flows into stick II control valve (36), through return passage (29), through passage (46), and through return line (51). Return oil then flows into the hydraulic tank.
Stick In (Dig Operation with One - Pump Flow)
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| Illustration 3 | g03415632 |
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Hydraulic schematic for STICK IN (dig operation with one-pump flow) (1) Line (2) Stick cylinder (3) Line (4) Pilot line (5) Line (6) Passage (7) Passage (8) Pilot line (9) Stick I control valve (10) Implement pressure switch (11) Line (12) Main control valve (13) Pilot line (14) Passage (15) Passage (16) Stick drift reduction valve (17) Passage (18) Center bypass passage (19) Passage (20) Load check valve (21) Passage (22) Stick regeneration valve (23) Parallel feeder passage (24) Center bypass passage (25) Passage (26) Line relief valve (rod end) (27) Line relief valve (head end) (28) Valve (29) Return passage (30) Passage (31) Stick unloading valve (32) Passage (33) Check valve (34) Passage (35) Parallel feeder passage (36) Stick II control valve (37) Passage (38) Check valve (39) Line (40) Passage (41) Return passage (42) Passage (43) Passage (NFC signal) (44) Line (45) Check valve (46) Passage (47) Line (48) Pressure reducing valve for boom priority (49) Pilot control valve (stick and swing) (50) Line (51) Return line (52) Idler pump (53) Pilot pump (54) Drive pump | |
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| Illustration 4 | g03418876 |
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STICK IN (dig operation with one-pump) (1) Line (2) Stick cylinder (3) Line (7) Passage (8) Pilot line (9) Stick I control valve (13) Pilot line (15) Passage (16) Stick drift reduction valve (17) Passage (18) Center bypass passage (19) Passage (20) Load check valve (21) Passage (28) Valve (30) Passage (36) Stick II control valve (37) Passage (38) Check valve (39) Line (40) Passage (42) Passage (43) Passage (NFC signal) (44) Line | |
When the joystick for the stick is moved less than half of the travel distance for a STICK IN operation, the pilot oil pressure that is supplied to stick I control valve (9) and stick II control valve (36) is reduced.
When the stick is moved with one-pump flow, pilot oil causes stick I control valve (9) and valve (28) to shift. The pilot oil pressure will not shift stick II control valve (36) or stick regeneration valve (22). The force of the spring in stick I control valve (9) is less than the force of the spring in stick II control valve (36). Because of the reduced pilot oil pressure, stick I control valve (9) will open and stick II control valve (36) will remain closed.
The pilot oil in pilot line (39) shifts the spool of stick I control valve (9) up. During a one-pump flow STICK IN operation, idler pump (52) is used. The oil delivery from idler pump (52) that is in parallel feeder passage (23) flows through passage (21), through load check valve (20), and to stick I control valve (9). The oil then flows through passage (15) and through line (1) to the head end of stick cylinder (2). Return oil from the rod end of stick cylinder (2) flows through line (3), through passage (14) and through stick drift reduction valve (16). Oil then flows through passage (17), through stick I control valve (9) and into the return hydraulic system. The stick moves to the IN position.
Without the oil delivery from drive pump (54), the cylinder rod movement is slow during a STICK IN operation. The low speed operation of the stick is performed.
Stick IN (Dig Operation with Two - Pump Flow)
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| Illustration 5 | g03415648 |
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Partial schematic for STICK IN (dig operation with two-pump flow) (1) Line (2) Stick cylinder (3) Line (9) Stick I control valve (14) Passage (15) Passage (16) Stick drift reduction valve (17) Passage (22) Stick regeneration valve (30) Passage (31) Stick unloading valve (34) Passage (36) Stick II control valve (42) Passage (52) Idler pump (54) Drive pump | |
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| Illustration 6 | g03419695 |
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STICK IN (dig operation with two-pump) (1) Line (2) Stick cylinder (3) Line (7) Passage (8) Pilot line (9) Stick I control valve (13) Pilot line (15) Passage (16) Stick drift reduction valve (17) Passage (18) Center bypass passage (19) Passage (20) Load check valve (21) Passage (28) Valve (30) Passage (36) Stick II control valve (37) Passage (38) Check valve (39) Line (40) Passage (42) Passage (43) Passage (NFC signal) (44) Line | |
When the joystick for the stick is moved more than half of the travel distance for STICK IN, the pilot oil pressure that is supplied to stick I control valve (9) and stick II control valve (36) is increased. Drive pump (54) and idler pump (52) are used for two-pump flow during a STICK IN operation.
When the stick is moved with two-pump flow, pilot oil causes stick I control valve (9), stick II control valve (36), stick regeneration valve (22) and stick drift reduction valve (16) to shift.
The oil delivery from drive pump (54) and idler pump (52) flows through passage (42), through passage (15), through line (1), and then flows to the head end of stick cylinder (2). A portion of the oil delivery from drive pump (54) and idler pump (52) also flows through passage (34) to stick regeneration valve (22). Oil delivery pressure in passage (34) causes stick unloading valve (31) to shift.
Return oil from the rod end of stick cylinder (2) flows through line (3), through passage (14) , through stick drift reduction valve (16), through passage (17) and through stick I control valve (9) to the return hydraulic system. The orifice in stick I control valve (9) causes the return oil pressure in line (3) to increase. A portion of the return oil flow from line (3) flows through passage (30) to stick regeneration valve (22). Return oil then flows through stick regeneration valve (22) to stick unloading valve (31). From stick unloading valve (31), the return oil flows into the return hydraulic system. The stick moves to the IN position.
Note: Refer to "Stick Regeneration Valve" for additional information on stick regeneration valve.
Stick In (Fast with Regeneration - Work Tool Suspended)
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| Illustration 7 | g03415647 |
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Hydraulic schematic for STICK IN (fast with regeneration - work tool suspended) (1) Line (2) Stick cylinder (3) Line (4) Pilot line (5) Line (6) Passage (7) Passage (8) Pilot line (9) Stick I control valve (10) Implement pressure switch (11) Line (12) Main control valve (13) Pilot line (14) Passage (15) Passage (16) Stick drift reduction valve (17) Passage (18) Center bypass passage (19) Passage (20) Load check valve (21) Passage (22) Stick regeneration valve (23) Parallel feeder passage (24) Center bypass passage (25) Passage (26) Line relief valve (rod end) (27) Line relief valve (head end) (28) Valve (29) Return passage (30) Passage (31) Stick unloading valve (32) Passage (33) Check valve (34) Passage (35) Parallel feeder passage (36) Stick II control valve (37) Passage (38) Check valve (39) Line (40) Passage (41) Return passage (42) Passage (43) Passage (NFC signal) (44) Line (45) Check valve (46) Passage (47) Line (48) Pressure reducing valve for boom priority (49) Pilot control valve (stick and swing) (50) Line (51) Return line (52) Idler pump (53) Pilot pump (54) Drive pump (55) Boom dampening valve | |
The STICK IN operation contains a regeneration circuit. When the joystick for the stick is moved to the STICK IN position, stick regeneration valve (22) and stick unloading valve (31) are operational in the stick hydraulic circuit. The return oil from the rod end of stick cylinder (2) is supplied to the head end of the stick cylinder. The regeneration circuit makes more effective use of the return oil from the stick cylinder. This action allows the oil delivery from the drive pump (54) and the idler pump (52) to perform other implement operations during a STICK IN operation.
When the joystick for the stick is moved to the STICK IN position, pilot oil from pilot control valve (49) flows through pilot line (50). The pilot oil flow then divides into several flow paths. The first path the pilot oil flows is through pilot line (39) to stick I control valve (9). The second path pilot oil flows is through pilot line (47), and through pilot line (11) to stick regeneration valve (22). The third path pilot oil flows is through pilot line (5), through passage (6), and to valve (28). The remainder of the pilot oil flows through pilot line (47), pressure reducing valve for boom priority (48), and pilot line (44) to stick II control valve (36).
Since pilot oil pressure has caused the spool in stick I control valve (9) to shift upward, the oil delivery from idler pump (52) flows through parallel feeder passage (23), through passage (21), and through load check valve (20). Pilot oil then flows through stick I control valve (9), through passage (15),and into line (1).
The pilot oil pressure in pilot line (44) has caused the spool in stick II control valve (36) to shift upward. Part of the oil delivery from the drive pump that is in center bypass passage (24) flows through check valve (45) and through stick II control valve (36). The oil then flows to passage (42). The remainder of the oil delivery from the drive pump flows through parallel feeder passage (35), through check valve (38), and through stick II control valve (36) to passage (42). All of the oil delivery from the drive pump in passage (42) flows to line (1) and combines with the oil delivery from the idler pump. The combined pump oil flows to the head end of stick cylinder (2).
The return oil from the rod end of the stick cylinder flows through line (3) to stick drift reduction valve (16). Pilot oil flow in passage (6) shifts valve (28) to the right. Back pressure in valve (16) is relieved to the hydraulic tank and stick drift reduction valve (16) shifts downward. The return oil enters passage (17). Part of the return oil in passage (17) flows through stick I control valve (9), through return passage (29), and through return line (51) to the hydraulic tank. The remainder of the return oil flows to stick regeneration valve (22). Return oil from passage (32) flows through check valve (33). From check valve (33) the return oil flows to passage (42) in order to regenerate to the head end of the stick cylinder.
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| Illustration 8 | g03424436 |
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Partial schematic for STICK IN (fast with regeneration) (22) Stick regeneration valve (31) Stick unloading valve (33) Load check valve (60) Passage | |
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| Illustration 9 | g03415751 |
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Stick IN (fast with regeneration) (11) Line (22) Stick regeneration valve (32) Passage (33) Load check valve (42) Passage (56) Spool | |
Stick regeneration valve (22) utilizes the return oil from the rod end of stick cylinder (2) in order to prevent cavitation within the head end of the stick cylinder. When the joystick for the stick is moved to the STICK IN position, pilot oil from pilot line (11) flows to stick regeneration valve (22) and the oil shifts spool (56) of stick regeneration valve (22).
Return oil from the rod end of stick cylinder (2) flows through line (3) to stick drift reduction valve (16). Since valve (28) relieves the back pressure on stick drift reduction valve (16), the stick drift reduction valve opens and oil flows through the stick II control valve (36) to stick regeneration valve (22). The oil flows from regeneration valve (22) through passage (32) to load check valve (33). From load check valve (33) the oil flows to passage (42) and combines with the oil in passage (15). The combined oil flows to the head end of stick cylinder (2).
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| Illustration 10 | g03415753 |
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Stick unloading valve (31) Stick unloading valve (32) Passage (42) Passage (57) Spring (58) Piston (59) Passage (60) Passage (61) Passage | |
Stick unloading valve (31) works with stick regeneration valve (22) in order to relieve high pressure in the head end of stick cylinder (2) during a STICK IN operation.
Because of the volume of oil that is forced into the head end of the stick cylinder during the regeneration cycle of the STICK IN operation, the pressure of the oil in the head end of the stick cylinder increases. The high-pressure oil flows through passage (15) and passage (42). The high-pressure oil pressure in passage (42) flows through passage (61) and to passage (59). The high-pressure oil now acts on the end of piston (58) and shifts the piston upward against stick unloading valve (31). When the force of the high-pressure oil becomes greater than the force of spring (57), the stick unloading valve shifts upward. The return oil from the rod end of the stick cylinder in passage (14) flows through stick I control valve (9) and to stick regeneration valve (22). The oil then flows through passage (32), through stick unloading valve (31), and through return passage (60) to the hydraulic tank. The return oil from the rod end of the stick cylinder is quickly unloaded. At this time, the regeneration circuit for the stick cylinder is inoperable.
When the oil pressure at the head end of the stick cylinder decreases, the oil pressure that acts on the end of stick unloading valve (31) also decreases. The force of spring (57) shifts the stick unloading valve downward. The return oil from the rod end of the stick cylinder is supplied to the head end of the stick cylinder. The regeneration circuit is again operable.