Main Control Valve

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EXCAVATOR 320C EXCAVATOR PAB Configuración: 320C & 320C L Excavators PAB00001-UP (MACHINE) (MACHINE) POWERED BY 3066 Engine Producto: Modelo:

Operación de Sistemas 320C Excavator Hydraulic System Número de medio -RENR3816-10

Fecha de publicación -01/02/2010

Fecha de actualización -19/02/2010

i01859537

Main Control Valve SMCS - 5051

Illustration 1

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Hydraulic schematic (1) Stick drift reduction valve (2) Line relief valve (stick cylinder rod end) (3) Boom drift reduction valve (4) Line relief valve (boom cylinder head end) (5) Return port (6) Main control valve (7) Stick regeneration valve

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(8) Load check valve (9) Parallel feeder passage (10) Straight travel solenoid valve (11) Right travel control valve (12) Attachment control valve (13) Bucket control valve (14) Center bypass passage (15) Boom I control valve (16) Stick II control valve (17) Relief valve (negative flow) (18) Straight travel control valve (19) Relief valve (negative flow) (20) Negative flow control orifice (21) Boom II control valve (22) Stick I control valve (23) Center bypass passage (24) Swing control valve (25) Left travel control valve (26) Load check valve (27) Boom regeneration valve (28) Line relief valve (boom cylinder rod end) (29) Negative flow control orifice (30) Line relief valve (stick cylinder head end) (31) Variable swing priority valve (32) Main relief valve (33) Stick unloading valve (34) Line relief valve (bucket cylinder rod end) (35) Line relief valve (bucket cylinder head end) (36) Parallel feeder passage (37) Inlet port (left pump) (38) Negative flow control line (left pump) (39) Inlet port (right pump) (40) Negative flow control line (right pump) (41) Left pump


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(42) Pilot pump (43) Right pump (44) Hydraulic tank

Illustration 2

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Main control valve ports (AR1) Right travel co ntrol valve (REVERSE TRAVEL) (AR2) Attachment control valve (port) (AR3) Bucket control valve (BUCKET CLOSE) (AR4) Boom I control valve (BOOM LOWER) (AR5) Stick II control valve (STICK IN) (BR1) Right travel control valve (FORWARD TRAVEL) (BR2) Attachment control valve (port) (BR3) Bucket control valve (BUCKET OPEN) (BR4) Boom I control valve ( BOOM RAISE) (BR5) Stick II control valve (STICK OUT) (AL1) Left travel control (REVERSE TRAVEL)


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(AL2) Swing control valve (SWING LEFT) (AL3) Stick I control valve (STICK IN) (AL4) Boom II control valve (BOOM RAISE) (BL1) Left travel control valve (FORWARD TRAVEL) (BL2) Swing control valve (SWING RIGHT) (BL3) Stick I control valve (STICK OUT) (aR1) Pilot port at right travel co ntrol valve (REVERSE TRAVEL) (aR2) Pilot port at attachment control valve (aR3) Pilot port at bucket con trol valve (BUCKET CLOSE) (aR4) Pilot port at boom I control valve (BOOM LOWER) (aR5) Pilot port at stick II con trol valve (STICK IN) (aL1) Pilot port at left travel control v alve (REVERSE TRAVEL) (aL2) Pilot port at swing control v alve (SWING LEFT) (aL3) Pilot port at stick I con trol valve (STICK IN) (aL4) Pilot port at boom II control valve (BOOM RAISE) (bR1) Pilot port at right travel control valve (FORWARD TRAVEL) (bR2) Pilot port at attachment control valve (bR3) Pilot port at bucket control valve (BUCKET OPEN) (bR4) Pilot port at boom I control valve (BOOM RAISE) (bR5) Pilot port at stick II control valve (STICK OUT) (bL1) Pilot port at left travel control valve (FORWARD TRAVEL) (bL2) Pilot port at swing control valve (SWING RIGHT) (bL3) Pilot port at stick I control valve (STICK OUT) (bL4) Pilot port at boom II control valve (STICK IN) (DST) Drain port (straight travel control valve) (HL) Negative flow signal pressure port (left p ump) (HR) Negative flow signal pressure port (right pump) (Pi1) Pilot port (boom regeneration valve) (Pi2) Pilot port (stick regeneration valve) (Pi3) Pilot port (variable swing priority valve) (Pi4) Pilot port (straight travel solenoid valve) (R2) Return port (R3) Return port


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Introduction

Illustration 3

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(10) Straight travel solenoid valve (11) Right travel control valve (12) Attachment control valve (13) Bucket control valve (15) Boom I control valve (16) Stick II control valve (18) Straight travel control valve (21) Boom II control valve (22) Stick I control valve (24) Swing control valve (25) Left travel control valve (28) Line relief valve (boom cylinder rod end) (30) Line relief valve (stick cylinder head end) (32) Main relief valve (34) Line relief valve (bucket cylinder rod end) (45) Right body (46) Left body


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Illustration 4

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Main control valve (bottom view) (3) Boom drift reduction valve (4) Line relief valve (boom cylinder head end)

Illustration 5

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Bottom view of main control valve (1) Stick drift reduction valve (2) Line relief valve (stick cylinder rod end)

Main control valve (6) is located in the hydraulic system between the main pumps and actuators (cylinders and motors). Depending on the machine operation, operation, the oil flow from right pump (43), left pump (41) and and pilot pump (42) to the hydraulic hydraulic circuits circuits are controlled controlled by the operation operation of each each component in the main control valve. By this control, the speed and direction of the cylinders and the motors can be controlled and adjusted. The pump delivery pressure can be controlled and adjusted. The main control valve includes right body (46) and left body (45). The main control valve is coupled together with bolts in order to make one assembly. 1. The right travel control control valve (11), (11), attachment attachment control control valve (12), (12), bucket bucket control valve (13), boom I control control valve (15) and stick II control valve (16) (16) are located located in right body body (46). The right pump oil is delivered through through inlet port (39), center bypass passage passage (14) and return return port (5) to hydraulic tank (44). In addition, the following components are located in right body (46) . a. The line line relief valve valve (bucket (bucket cylinder cylinder rod end) end) (34) and the line line relief valve valve (bucket (bucket cylinder head end) (35) limit the pressure in the bucket circuit due to external forces. b. When the joysticks joysticks and/or travel levers/pedals levers/pedals are in the the NEUTRAL position, or when the joysticks and/or and/or travel levers/pedals levers/pedals are partially moved from the NEUTRAL NEUTRAL position, position, negative flow control relief valve (19) and the negative flow control orifice (29) decrease the pump flow. c. Boom drift drift reduction reduction valve valve (3) prevents prevents boom boom drift when when the joystick joystick for the boom boom is in the NEUTRAL position. The line relief valve (boom cylinder head end) (4) is mounted on the boom drift reduction valve. The line relief valve (boom cylinder rod end) (28) is also located on the right body. d. Boom regeneration regeneration valve valve (27) supplies supplies return return oil from from the head head end of the boom cylinders cylinders to the rod end of the boom cylinders when the boom is lowered. e. Load check check valves valves (26) are part of the following control valves: attachment attachment control valve valve (12), bucket control valve (13), boom I control valve (15) and stick II control valve (16) . 1. Straight travel travel control control valve (18), (18), left travel control control valve (25), swing control valve (24), stick I


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control valve (22) and boom II control valve (21) are located in left body (45). The left pump oil is delivered through inlet port (37), center bypass passage (23) and return port (5) to hydraulic tank (44). In addition, the following components are located in left body (45) . a. Stick drift drift reduction valve (1) prevents stick stick drift when the joystick for for the stick is in the NEUTRAL position. position. The line relief valve valve (stick cylinder cylinder rod end) (2) is mounted mounted on the stick drift reduction valve. The line relief valve (stick cylinder head end) (30) is also located on the left body. b. When the joysticks joysticks and/or travel levers/pedals levers/pedals are in the the NEUTRAL position, or when the joysticks and/or and/or travel levers/pedals levers/pedals are partially moved from the NEUTRAL NEUTRAL position, position, negative flow control relief valve (17) and the negative flow control orifice (20) decrease the pump flow. c. Stick regeneration regeneration valve valve (7) supplies supplies return oil from the rod end end of the the stick cylinder to the head end of the stick cylinder during the stick in function. d. Stick unloading unloading valve (33) reduces reduces the back back pressure in the rod rod end of of the stick stick cylinder during the stick in function. e. Load check check valves (8) are part of the following control valves: valves: swing control valve valve (24) and stick I control valve (22) . f. Main relie relieff valve valve (32) limits limits the the main hydra hydraulic ulic system system pressu pressure. re. 

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When the main control valve is in the NEUTRAL position, no pump oil flows to the cylinders and the motors. Main control valve operation in the NEUTRAL position is described later in this section. The main control valve controls the negative flow control signal. For more information on the negative flow control operation, refer to Systems Operation, "Negative Flow Control". The main control valve prevents cylinder drift with the load check valves. For more information on the load check valves, refer to Systems Operation, "Check Valve (Load)". The main control valve limits the circuit pressure with relief valve operation. For more information on the limitation of circuit pressure, refer to Systems Operation, "Relief Valve (Main)" and Systems Operation, "Relief Valve (Line)".

The description of other components that are installed on the main control valve or in the main control valve will be listed separately. Refer to the appropriate sections that are in this manual for further information on the components.

Main Control Valve Operation in NEUTRAL Position


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Illustration 6

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Main control valve (neutral position) (1) Stick II control valve (2) Boom I control valve (3) Bucket control valve (4) Attachment control valve (5) Right travel control valve (6) Parallel feeder passage (7) Inlet port (8) Straight travel control valve (9) Left travel control valve (10) Parallel feeder passage (11) Swing control valve (12) Stick I control valve (13) Boom II control valve (14) Right body (15) Left body (16) Negative flow control orifice (17) Return port (18) Negative flow control orifice (19) Return passage (20) Center bypass passage


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(21) Inlet port (22) Center bypass passage (23) Return passage

The right pump supplies oil to right body (14) through inlet port (7). The oil then flows through center bypass passage passage (20) and parallel feeder feeder passage (6). The left pump pump supplies oil oil to left body (15) through inlet port (21). The oil then flows through center bypass passage (22) and parallel feeder passage (10) . When all of the joysticks and/or travel levers/pedals are in the NEUTRAL position, right pump oil flows through center bypass passage (20), negative flow control orifice (18), return passage (19), return passage (23) and return port (17) back to the hydraulic tank. Left pump oil from inlet port (21) flows through center bypass passage (22), negative flow control orifice (16) and return port (17) back to the hydraulic tank. Oil in parallel feeder passages (6) and (10) remains blocked by each control valve spool. Activation of any joystick and/or travel levers/pedals provides two paths for right pump oil. One path flows through center bypass passage (20) to right travel control valve (5). The other path flows through parallel feeder feeder passage (6), (6), attachment attachment control valve (4), bucket control valve (3) (3) and boom I control valve (2). Activation of any joystick and/or travel levers/pedals also provides two paths for left pump oil. One path flows through center bypass passage (22) to left travel control valve (9) and stick I control valve (12). The other path flows through parallel feeder passage (10) to swing control valve (11) .

Individual Valve Operation


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320C & 320C L Excavators PAB00001-UP (MACHINE) POWERED BY 3066 ...

Illustration 7

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Bucket control valve (NEUTRAL position) (1) Line relief valve (bucket cylinder rod end) (2) Port (3) Parallel feeder passage (4) Load check valve (5) Passage (6) Port (7) Line relief valve (bucket cylinder head end) (8) Pilot port (9) Pilot port (10) Return passage (11) Spool (12) Center bypass passage (13) Spring


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The bucket control valve is used as a typical example for describing the operation of individual control valves. When the joysticks and/or travel levers/pedals are in the NEUTRAL position, pilot oil does not flow to port (8) and port (9). Spool Spool (11) is centered in the NEUTRAL position by the force of spring spring (13). The right pump oil flows through center bypass passage (12) to the hydraulic tank.

Illustration 8

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Bucket control valve BUCKET CLOSE (2) Port (3) Parallel feeder passage (4) Load check valve (5) Passage (6) Port (8) Pilot port (10) Return passage (11) Spool (12) Center bypass passage (14) Passage (15) Passage

When the joystick for the bucket is moved to the BUCKET CLOSE position, pilot oil is supplied to pilot port (8). (8). Spool (11) (11) moves to the left. Center bypass passage passage (12) is closed closed and passage passage (15) becomes opened. opened. Port (14) is now connected connected to return passage (10) .


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Oil that is in parallel feeder passage (3) flows through load check valve (4), passage (5) and passage (15). The oil then flows to port (6). The bucket cylinder rod extends. When the bucket cylinder rod extends, the displaced oil in the rod end flows to port (2) . Oil flows through port (2) to return passage (14) and back to the hydraulic tank.

Copyright 1993 - 2013 Caterpillar Inc. Todos los derechos reservados. Red privada para licenciados del SIS.

Tue May 14 05:51:49 UTC+0200 2013


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Main Control Valve

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