Control Valve (Lift)
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| Illustration 1 | g01945475 |
(1) Relief valve (2) Port to the head end of the cylinders (3) Load sensing passage (4) Spool (5) Port to the rod end of the cylinders (6) Makeup valve (7) Spool (8) Pilot solenoid valve (9) Passage (10) Passage (11) Bridge passage (12) Bridge passage (13) Feeder passage (14) Passage from implement pump (15) Bridge passage (16) Resolver (17) Passage (18) Passage (19) Spring | |
When the lift circuit is the only hydraulic circuit in operation, the circuit will have the highest signal oil pressure in the hydraulic system. When the control handle is moved to the RAISE position, pilot oil enters the control valve through pilot solenoid valve (8). The pilot oil flows into passage (10). When the pilot oil overcomes the force of spring (19), spool (7) moves to the left.
Pump supply oil flows from passage (14) around the spool to feeder passage (13). As the oil flows into feeder passage (13), oil pressure increases. This increase in oil pressure causes spool (4) to move upward.
The oil then flows to bridge passage (12) and bridge passage (15) .
In bridge passage (12), spool (7) blocks the flow of the oil. In bridge passage (15), the hydraulic oil flows around spool (7) into passage (17). The hydraulic oil flows through port (2) to the head end of the lift cylinders.
Some of the oil that flows through spool (4) flows around the spool into the spring chamber that is on top of the spool. The flow of oil into the spring chamber causes the oil pressure in the chamber to increase. The force of the spring and the oil pressure in the spring chamber will equal the oil pressure that is flowing to the lift cylinders.
The oil pressure in the spring chamber is sensed in resolver (16). If this circuit is the only circuit that is active, or this circuit has a work port pressure that is higher than the other circuits that are active, the load sensing pressure flows into the load sensing passage (3) until the oil pressure in the load sensing passage is equal to the oil pressure that flows to the work tool. This pressure flows to the pump actuator group in order to control the output from the pump.
Hydraulic oil flows from the rod end of the bucket lift cylinders through port (5) into passage (11). The hydraulic oil flows around spool (7) into passage (9). Then, the hydraulic oil flows to the tank.
When the operator releases the control handle, the flow of pilot oil to the valve is blocked. The pilot oil in passage (10) drains to the tank. The loss of pilot oil enables spring (19) to move spool (7) to the HOLD position. Spool (7) blocks the hydraulic oil in the hydraulic lines.
The lift circuit has a relief valve (1) that makes sure that the pressure in the lift cylinders does not exceed a preset limit. A makeup valve is integrated into relief valve (1) and makeup valve (6). Relief valve (1) is located on the RAISE side of the control valve. Makeup valve (6) is located on the LOWER side of the control valve. The makeup valves make sure that the lift cylinders do not cavitate when the bucket is operated.
Control Valve (Tilt)
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| Illustration 2 | g01945476 |
(1) Relief valve (2) Port to the head end of the cylinders (3) Load sensing passage (4) Spool (5) Port to the rod end of the cylinders (7) Spool (8) Pilot solenoid valve (9) Passage (10) Passage (11) Bridge passage (12) Bridge passage (13) Feeder passage (14) Passage from implement pump (15) Bridge passage (16) Resolver (17) Passage (18) Passage (19) Spring (20) Dual stage relief valve | |
When the tilt circuit is the only hydraulic circuit in operation, the circuit will have the highest signal oil pressure in the hydraulic system. When the control handle is moved to the TILT BACK position, pilot oil enters the control valve through pilot solenoid valve (8). The pilot oil flows into passage (10). When the pilot oil overcomes the force of spring (19), spool (7) moves to the left.
Pump supply oil flows from passage (14) around the spool to feeder passage (13). As the oil flows into feeder passage (13), oil pressure increases. This increase in oil pressure causes spool (4) to move upward.
The oil then flows to bridge passage (12) and bridge passage (15) .
In bridge passage (12), spool (7) blocks the flow of the oil. In bridge passage (15), the hydraulic oil flows around spool (7) into passage (17). The hydraulic oil flows through port (2) to the head end of the tilt cylinder.
Some of the oil that flows through the spool (4) flows around the spool into the spring chamber that is on top of the spool. The flow of oil into the spring chamber causes the oil pressure in the chamber to increase. The force of the spring and the oil pressure in the spring chamber will equal the oil pressure that is flowing to the tilt cylinders.
The oil pressure in the spring chamber is sensed in resolver (16). If this circuit is the only circuit that is active, or this circuit has a work port pressure that is higher than the other circuits that are active, the load sensing pressure flows into the load sensing passage (3) until the oil pressure in the load sensing passage is equal to the oil pressure that flows to the work tool. This pressure flows to the pump actuator group in order to control the output from the pump.
Hydraulic oil flows from the rod end of the bucket tilt cylinder through port (5) into passage (11). The hydraulic oil flows around spool (7) into passage (9). Then, the hydraulic oil flows to the tank.
When the operator releases the control handle, the flow of pilot oil to the valve is blocked. The pilot oil in passage (10) drains to the tank. The loss of pilot oil enables spring (19) to move spool (7) to the HOLD position. Spool (7) blocks the hydraulic oil in the hydraulic lines.
The tilt circuit has relief valve (1) and dual stage relief valve (20). The relief valve makes sure that the pressure in the tilt cylinder does not exceed a preset limit. Dual stage relief valve (20) is located in the DUMP side of the control valve. The relief valve makes sure that the pressure in the tilt cylinder does not exceed a preset limit. During backdragging operations, this valve uses pressure from the rod end of the lift cylinders to increase the setting. Makeup valves are integrated into both relief valve (1) and dual stage relief valve (20) in order to make sure that the tilt cylinders do not cavitate when the bucket is operated.
Control Valve (Multipurpose Bucket)
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| Illustration 3 | g01945477 |
(1) Relief valve (2) Port to the head end of the cylinders (3) Load sensing passage (4) Spool (5) Port to the rod end of the cylinders (7) Spool (8) Pilot solenoid valve (9) Passage (10) Passage (11) Bridge passage (12) Bridge passage (13) Feeder passage (14) Passage from implement pump (15) Bridge passage (16) Resolver (17) Passage (18) Passage (19) Spring (20) Dual stage relief valve (21) Anti-drift valve | |
When the circuit for the multipurpose bucket is the only hydraulic circuit in operation, the circuit will have the highest signal oil pressure in the hydraulic system. When the thumb wheel is moved to the CLOSE position, pilot oil enters the control valve through pilot solenoid valve (8). The pilot oil flows into passage (10). When the pilot oil overcomes the force of spring (19), spool (7) moves to the left.
Pump supply oil flows from passage (14) around the spool to feeder passage (13). As the oil flows into feeder passage (13), oil pressure increases. This increase in oil pressure causes spool (4) to move upward.
The oil then flows to bridge passage (12) and bridge passage (15) .
In bridge passage (12), spool (7) blocks the flow of the oil. In bridge passage (15), the hydraulic oil flows around the spool (7) into passage (17). The hydraulic oil flows past anti-drift valve (21) through port (2) to the head end of the cylinders.
Anti-drift valve (21) hydraulically locks the multipurpose bucket in the CLOSED position until anti-drift valve (21) receives a command from spool (7) .
Some of the oil that flows through the spool (4) flows around the spool into the spring chamber that is on top of the spool. The flow of oil into the spring chamber causes the oil pressure in the chamber to increase. The force of the spring and the oil pressure in the spring chamber will equal the oil pressure that is flowing to the multipurpose bucket cylinders.
The oil pressure in the spring chamber is sensed in resolver (16). If this circuit is the only circuit that is active, or this circuit has a work port pressure that is higher than the other circuits that are active, the load sensing pressure flows into the load sensing passage (3) until the oil pressure in the load sensing passage is equal to the oil pressure that flows to the work tool. This pressure flows to the pump actuator group in order to control the output from the pump.
Hydraulic oil flows from the rod end of the cylinders through port (5) into passage (11). The hydraulic oil flows around spool (7) into passage (9). Then, the hydraulic oil flows to the tank.
When the operator stops rolling the roller switch, the flow of pilot oil to the valve is blocked. The pilot oil in passage (10) drains to the tank. The loss of pilot oil enables spring (19) to move spool (7) to the HOLD position. Spool (7) blocks the hydraulic oil in the hydraulic lines.
The circuit for the multipurpose bucket also has relief valve (1) and dual stage relief valve (20). The dual stage relief valve is located in the CLOSE side of the control valve. The relief valves absorb shocks. The relief valves also make sure that the pressure in the multipurpose bucket cylinders does not exceed a preset limit. During backdragging operations, dual stage relief valve (20) uses pressure from the rod end of the lift cylinders in order to increase the setting. Makeup valves are integrated into both relief valve (1) and dual stage relief valve (20) in order to make sure that the multipurpose bucket cylinders do not cavitate when the multipurpose bucket is operated.
Control Valve (Ripper)
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| Illustration 4 | g01945479 |
(1) Relief valve (2) Port to the head end of the cylinders (3) Load sensing passage (4) Spool (5) Port to the rod end of the cylinders (7) Spool (8) Pilot solenoid valve (9) Passage (10) Passage (11) Bridge passage (12) Bridge passage (13) Feeder passage (14) Passage from implement pump (15) Bridge passage (16) Resolver (17) Passage (18) Passage (19) Spring (21) Anti-drift valve | |
When the circuit for the ripper is the only hydraulic circuit in operation, the circuit will have the highest signal oil pressure in the hydraulic system. When the controller is moved to the RAISE position, pilot oil enters the control valve through pilot solenoid valve (8). The pilot oil flows into passage (18). When the pilot oil overcomes the force of spring (19), spool (7) moves to the left.
Pump supply oil flows from passage (14) around the spool to feeder passage (13). As the oil flows into feeder passage (13), oil pressure increases. This increase in oil pressure causes spool (4) to move upward.
The oil then flows to bridge passage (12) and bridge passage (15) .
In bridge passage (12), spool (7) blocks the flow of the oil. In bridge passage (15), the hydraulic oil flows around the spool (7) into passage (17). The hydraulic oil flows past anti-drift valve (21) through port (5) to the rod end of the cylinders.
Anti-drift valve (21) hydraulically locks the ripper in the RAISED position until anti-drift valve (21) receives a command from spool (7) .
Some of the oil that flows through the spool (4) flows around the spool into the spring chamber that is on top of the spool. The flow of oil into the spring chamber causes the oil pressure in the chamber to increase. The force of the spring and the oil pressure in the spring chamber will equal the oil pressure that is flowing to the tilt cylinders.
The oil pressure in the spring chamber is sensed in resolver (16). If this circuit is the only circuit that is active, or this circuit has a work port pressure that is higher than the other circuits that are active, the load sensing pressure flows into the load sensing passage (3) until the oil pressure in the load sensing passage is equal to the oil pressure that flows to the work tool. This pressure flows to the pump actuator group in order to control the output from the pump.
Hydraulic oil flows from the head end of the cylinders through port (2) into passage (11). The hydraulic oil flows around spool (7) into passage (9). Then, the hydraulic oil flows to the tank.
When the operator releases the control handle, the flow of pilot oil to the valve is blocked. The pilot oil in passage (18) drains to the tank. The loss of pilot oil enables spring (19) to move spool (7) to the HOLD position. Spool (7) blocks the hydraulic oil in the hydraulic lines.
The ripper circuit has two relief valves (1) in order to make sure that the pressure in the ripper cylinders does not exceed a preset limit. Makeup valves are integrated into both relief valves (1) in order to make sure that the ripper cylinders do not cavitate when the ripper is operated.