HOLD Position
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| Illustration 1 | g02191595 |
(1) Spring (2) Port (3) Port (4) Spool (5) Passage | |
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| Illustration 2 | g02195813 |
(6) Left stabilizer control (7) Right stabilizer control (A) Stabilizer DOWN (B) HOLD (C) Stabilizer UP | |
When levers (6) and (7) are in position (B), the control valves are in the HOLD position. The spring (1) holds spool (4) in the centered position. No pilot oil enters the control valve through the passage (1) and port (3). Any pilot oil in the pilot lines drains through the pilot valve to the tank. The spool (4) blocks the flow of pump supply oil in passage (5) .
Passage (5) is common to all control valves in the bank valve. The passage has no outlet. The spool (4) blocks the flow of pump supply oil until the operator moves the pilot valve.
Stabilizer UP Position
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| Illustration 3 | g02193664 |
(1) Spring (2) Port (3) Port (4) Spool (5) Passage (8) Load check valve (9) Passage (10) Passage (11) Port (12) Passage (13) Chamber (14) Pressure compensator valve (15) Passage (16) Port (17) Passage (18) Relief valve (19) Load check valve (20) Spring (21) Chamber (22) Passage (23) Passage (24) Passage (25) Passage | |
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| Illustration 4 | g02195813 |
(6) Left stabilizer control (7) Right stabilizer control (A) Stabilizer DOWN (B) HOLD (C) Stabilizer UP | |
When the stabilizer circuit is the only hydraulic circuit in operation, the stabilizer circuit will have the highest signal oil pressure in the hydraulic system. When the control levers (6) and (7) are moved to position (C), the pilot valve is in the stabilizer UP. Pilot oil enters the control valve through chamber (2) and flows to chamber (21). When the pilot oil overcomes the force of spring (1), spool (4) moves to the left.
When the spool (4) moves to the left, pump supply oil flows from passage (5) around the spool and into passage (23) .
The hydraulic oil in passage (23) flows to pressure compensator valve (14). In the pressure compensator valve (14), the hydraulic oil flows into internal passages. The pressure compensator valve (14) moves up. As the pressure compensator valve (14) moves up, the cross-drilled passage is opened to an internal passage that is in the valve. Some of the hydraulic oil flows around the pressure compensator valve (14) to passage (12) and chamber (13). The hydraulic oil that flows to chamber (13) is signal oil. The signal oil balances the pressure compensator valve (14) against the hydraulic oil pressure in passage (23). This controls the flow across spool (4) .
The signal oil in the internal passage flows to the pressure compensator valve (14) in each control valve. The signal oil also flows to the pressure and flow compensator valve on the hydraulic pump. The signal oil helps to control the output of the hydraulic pump. The hydraulic pump upstrokes and the hydraulic oil pressure increases in passage (5) and in passage (23). As the hydraulic pressure in passage (23) overcomes the compensator valve (14), oil then goes into passage (10) and passage (15) .
In passage (10), spool (4) blocks the flow of oil. In passage (15), the oil flows around the spool (4) to chamber (22) .
When the oil pressure overcomes the check valve (19) and spring (20), the oil flows into passage (17) and out port (16) .
The oil that flows through port (16) flows to the rod end of the stabilizer cylinders. This raises the stabilizers.
Hydraulic oil from the head end of the stabilizer cylinders flows through port (11). The oil then flows to passage (9). From passage (9) the oil will flow through the check valve (8) and into passage (24). The hydraulic oil flows around spool (4) into passage (25) .
The hydraulic oil in passage (25) flows to all control valves as makeup oil. Then, the hydraulic oil flows to the tank.
When the operator returns the control levers (6) and (7) to position (B) the pilot valves return to HOLD position. The flow of pilot oil to the valve is blocked. The loss of pilot oil enables spring (1) to move spool (4) to the HOLD position.
If there is a spike in the oil pressure at port (16), the pressure will cause pressure relief valve (18) to send fluid back to the tank.
Stabilizer DOWN Position
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| Illustration 5 | g02195994 |
(1) Spring (2) Port (3) Port (4) Spool (5) Passage (8) Load check valve (9) Passage (10) Passage (11) Port (12) Passage (13) Chamber (14) Pressure compensator valve (15) Passage (16) Port (17) Passage (18) Relief valve (19) Load check valve (20) Spring (21) Chamber (22) Passage (23) Passage (24) Passage (25) Passage | |
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| Illustration 6 | g02195813 |
(6) Left stabilizer control (7) Right stabilizer control (A) Stabilizer DOWN (B) HOLD (C) Stabilizer UP | |
When the stabilizer circuit is the only hydraulic circuit in operation, the stabilizer circuit will have the highest signal oil pressure in the hydraulic system. When the control levers (6) and (7) are moved to position (A), the pilot valve is in the stabilizer DOWN. Pilot oil enters the control valve through chamber (2) and flows to chamber (21). When the force of spring (1) overcomes the pressure of the pilot oil in chamber (21), spool (4) moves to the right.
When the spool (4) moves to the right, pump supply oil flows from passage (5) around the spool and into passage (23) .
The hydraulic oil in passage (23) flows to pressure compensator valve (14). In the pressure compensator valve (14), the hydraulic oil flows into internal passages. The pressure compensator valve (14) moves up. As the pressure compensator valve (14) moves up, the cross-drilled passage is opened to an internal passage that is in the valve. Some of the hydraulic oil flows around the pressure compensator valve (14) to passage (12) and chamber (13). The hydraulic oil that flows to chamber (13) is signal oil. The signal oil balances the pressure compensator valve (14) against the hydraulic oil pressure in passage (23). This controls the flow across spool (4) .
The signal oil in the internal passage flows to the pressure compensator valve (14) in each control valve. The signal oil also flows to the pressure and flow compensator valve on the hydraulic pump. The signal oil helps to control the output of the hydraulic pump. The hydraulic pump upstrokes and the hydraulic oil pressure increases in passage (5) and in passage (23). As the hydraulic pressure in passage (23) overcomes the compensator valve (14), oil then goes into passage (10) and passage (15) .
In passage (15), spool (4) blocks the flow of oil. In passage (10), the oil flows around the spool (4) to chamber (24) .
When the oil pressure overcomes the check valve (8) and the spring, the oil flows into passage (9) and out port (11) .
The oil that flows through port (11) flows to the head end of the stabilizer cylinders. This lowers the stabilizers.
Hydraulic oil from the rod end of the stabilizer cylinders flows through port (16). The oil then flows to passage (17). From passage (17) the oil will flow through the relief valve (18) and check valve (19) into passage (22). The hydraulic oil flows around spool (4) into passage (25) .
The hydraulic oil in passage (25) flows to all control valves as makeup oil. Then, the hydraulic oil flows to the tank.
When the operator returns the control levers (6) and (7) to position (B) the pilot valves return to HOLD position. The flow of pilot oil to the valve is blocked. The loss of pilot oil enables spring (1) to move spool (4) to the HOLD position.
If there is a spike in the oil pressure at port (16), the pressure will cause pressure relief valve (18) to send fluid back to the tank.