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| Illustration 1 | g02428837 |
Main control valve (3-Function, with ride control) (1) 323-5820 Control Valve Gp (Tilt) (2) 323-5822 Control Valve Gp (Lift) (3) 326-7675 Ride Control Valve Gp (4) 261-0017 Control Valve Gp (Auxiliary) (5) 365-8152 Inlet Manifold Gp (6) 323-2298 Valve Manifold Gp | |
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| Illustration 2 | g02430540 |
Main control valve (3-Function, with ride control) schematic (1) 323-5820 Control Valve Gp (Tilt) (2) 323-5822 Control Valve Gp (Lift) (3) 326-7675 Ride Control Valve Gp (4) 261-0017 Control Valve Gp (Auxiliary) (5) 365-8152 Inlet Manifold Gp (6) 323-2298 Valve Manifold Gp (7) 353-7057 Ride Control Accumulator and Mounting Gp (8) 112-1817 Manual Valve Gp (Lowering control) (9) 332-1985 Relief Valve Gp (Line) (10) 328-4314 Solenoid Valve Gp (Drift reduction) (11) 272-2334 Relief Valve Gp (Line) (12) 241-5895 Solenoid Valve Gp (Hydraulic lockout) (13) 355-9981 Pilot Oil Accumulator Gp (14) 252-0737 Solenoid Valve Gp (15) 313-7668 Solenoid Valve Gp (Pilot Proportioning) (16) 4T-7581 Relief Valve Gp (Ride control) (17) 260-6734 Valve Stem (Tilt) (18) 349-0671 Valve Stem (Lift) (19) 235-6157 Shuttle Valve (Ride control) (20) 260-6736 Valve Stem (Auxiliary) (21) 260-8590 Shuttle Valve (22) 305-4563 Shuttle Valve (23) 318-8833 Check Valve Gp (24) 252-0737 Solenoid Valve Gp (25) 346-0474 Relief Valve Gp (26) Compensation and Load Check Valve (27) 331-9022 Relief Valve Gp (A) To hydraulic tank (B) Implement pump supply (C) Implement pump load sense (D) To hydraulic tank (E) Pilot oil | |
The supply oil flows from the implement piston pump to the main control valve at point (B). The main control valve controls the flow of hydraulic oil to the cylinders and to the ride control system.
Most of the supply oil flows to control valves for the implement circuits. Oil returns from the control valve and flows to the tank at point (A) .
The supply oil flows to the following components: tilt control valve (1), lift control valve (2), ride control valve (3) and auxiliary valve (4) .
Pilot oil flows into the main control valve from point (E). The oil that flows to pilot oil accumulator (13) charges the pilot oil accumulator. This accumulator pressure allows the bucket to be lowered if the engine stops. Then, the oil flows through the main control valve as pilot oil. The pilot oil flows through the solenoid valves in order to move the spools to the correct position. The key start switch must be in the ON position for this function to work. Manual valve (8) can be used to lower the bucket if no power can be supplied to the solenoids.
The oil that flows to the load sensing circuit enters signal duplicating valve (22). Normally, the oil flows through the signal duplicating valve.
Signal duplicating valve (22) and load sensing relief valve (25) operate for all of the control valves in the main control valve. Load sensing relief valve (25) limits the maximum signal pressure to the pump at point (C). Load sensing relief valve (25) drains excess signal oil to the tank at point (D). Signal duplicating valve (22) sends signal oil back to the implement piston pump at point (C) .
The control valves are proportional priority and pressure compensated. If a circuit is active, or if more than one circuit is active, signal duplicating valve (22) duplicates the highest signal oil pressure. The highest signal oil pressure is applied to all of the control valves.
Oil flow enters the control valve and flows through a parallel feeder passage to all circuits. All four circuits on the machine can be operated independently.
Both tilt control valve (1) and auxiliary control valve (4) have two line relief valves. One relief valve is for each end of the cylinders. Also, the tilt control valve, the lift control valve, and the ride control valve have an identical solenoid valve. The solenoids for the tilt control valve and the lift control valve are for drift reduction (10) .
ReferenceFor more information on the operation or the line relief valves, refer to Systems Operation, "Relief Valve (Line)".
ReferenceFor more information on the operation or the solenoid valves, refer to Systems Operation, "Implement Electronic Control System".
ReferenceFor more information on the operation of the Relief Valve (Load Sensing Signal), refer to Systems Operation, "Relief Valve (Load Sensing Signal)".
ReferenceThe operation of the ride control valve is explained in Systems Operation, "Ride Control System".
Tilt Control Valve
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| Illustration 3 | g02430836 |
Tilt Control Valve (1) in HOLD position. (9A) 332-1985 Relief Valve (Line) Rod End (9B) 332-1985 Relief Valve (Line) Head End (10) 328-4314 Solenoid Valve (Drift Reduction) (15) 313-7668 Solenoid Valve Gp (Pilot Proportioning) (17) 260-6734 Valve Stem (Tilt) (21) 260-8590 Shuttle Valve Load Signal Resolver (26) Compensation and Load Check Valve (28) Work Port to Head End of lift cylinder for Tilt Back position (29) Work Port for Rod End of lift cylinder for Dump Function (30) Bridge Passage (A) Tank Port (B) Pump Port | |
Oil from the implement piston pump flows to tilt control valve (1) at port (B). Tilt valve stem (17) is controlled by solenoids (15). Implement pump oil flows through tilt control valve (1) to lift control valve (2) at pump port (B). Tilt valve stem (17) is spring centered with a closed center. Tilt valve stem (17) has three positions: TILT BACK, HOLD and DUMP.
HOLD Position
Springs keep tilt valve stem (17) in the HOLD position when solenoids (15) have not been actuated. Stem movement is controlled by actuation of pilot proportioning solenoids (15) that allow oil to flow to either end of tilt valve stem (17) .
Tilt valve stem (17) in the hold position blocks the oil in both ends of the tilt cylinder. The stem prevents the tilt cylinder from moving. Solenoid valve (10) further limits movement toward the DUMP position if leakage occurs between valve stem (17) and the valve body.
TILT BACK Operation
When the tilt control lever is moved to the TILT BACK position, pilot oil is sent to the left end of tilt valve stem (17). Tilt valve stem (17) moves to the right. Pump oil is sent through the tilt control valve from port (B) around stem (17) to the bottom of compensation and load check valve (26). Compensation and load check valve (26) is pushed up and flow goes through the openings in the load check valve to bridge passage (30). Oil flows around tilt valve stem (17) and through solenoid valve (10) for drift reduction to work port (28) .
Oil flows to work port (28) to the head end of the tilt cylinder. The bucket will tilt back. Solenoid valves (15) and tilt valve stem (17) respond in proportion to the signal that is received from the operator controls.
Oil from the rod end of the tilt cylinder enters through work port (29) and exits to the hydraulic tank through passage (A) .
DUMP Operation
When the tilt control lever is moved to the DUMP position, pilot oil is sent to the right end of tilt valve stem (17). Tilt valve stem (17) moves to the left. Implement oil is sent from pump port (B) around tilt valve stem (17) to the bottom of compensation and check valve (26). Compensation and check valve (26) is pushed up and flow goes through the openings in load check valve (26) to bridge passage (30). Oil flows around tilt valve stem (17) to work port (29) .
Oil flows through work port (29) to the rod end of the tilt cylinder. The bucket will dump. Solenoid valves (15) and tilt valve stem (17) respond in proportion to the movement of the operator controls.
Oil from the head end of the tilt cylinder enters work port (28). The oil flows through energized solenoid valve (10) for drift reduction and exits through tank port (A) to the hydraulic tank.
ReferenceFor more information on the operation or the line relief valves, refer to Systems Operation, "Relief Valve (Line)".
ReferenceFor more information on the operation or the solenoid valves, refer to Systems Operation, "Implement Electronic Control System".
Lift Control Valve
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| Illustration 4 | g02430936 |
Lift Control Valve in HOLD position (10) 328-4314 Solenoid Valve (Drift Reduction) (15) 313-7668 Solenoid Valve (Pilot Proportioning) (18) 260-6735 Valve Stem (Lift) (21) 260-8590 Shuttle Valve Load Signal Resolver (26) Compensation and Load Check Valve (31) 234-4869 Makeup Valve (32) Work Port for lower function to rod end of lift cylinder (33) Work Port for lift function to head end of lift cylinder (34) 234-4870 Plug (35) Bridge Passage (A) Tank Port (B) Pump Port | |
Oil from the implement piston pump flows to lift control valve (2) at pump port (B). Pump oil flows from pump port (B) through lift control valve (2) to ride control valve (3) and auxiliary control valve (4). Lift valve stem (18) is controlled by solenoids (15). The lift valve stem is spring centered with a closed center. The lift valve stem has four positions: RAISE, HOLD, LOWER and FLOAT.
HOLD Position
Springs keep lift valve stem (18) in the HOLD position when solenoid valves (15) have not been actuated. Lift valve stem (18) in the HOLD position blocks the oil in both ends of the lift cylinders. The stem keeps the lift cylinders from moving.
Solenoid valve (10) further limits lift cylinder drift toward the lower position if leakage occurs between lift valve stem (18) and the valve body.
Stem movement is controlled by actuation of pilot proportioning solenoids (15) that allow oil to flow to either end of lift valve stem (18).
RAISE Operation
When the lift control lever is moved to the RAISE position, pilot oil is sent to the right end of lift valve stem (18). Lift valve stem (18) moves to the left. Implement pump oil is sent from pump port (B) around lift valve stem (18) to the bottom of compensation and check valve (26). Compensation and check valve (26) is pushed up and flow goes through the openings in load check valve (26) to bridge passage (35). Oil flows around lift valve stem (18) and through solenoid valve (10) for drift reduction to work port (33) .
Oil is allowed to flow to the head end of the lift cylinders. The bucket will rise. Solenoid valves (15) and lift valve stem (18) respond in proportion to the movement of the operator controls.
Oil from the rod end of the lift cylinders enters through work port (32) and exits through tank port (A) to the hydraulic tank.
LOWER Operation
When the lift control lever is moved to the LOWER position, pilot oil is sent to the left end of lift valve stem (18). Lift valve stem (18) moves partially to the right. Implement oil is sent from pump port (B) around lift valve stem (18) to the bottom of compensation and load check valve (26). Compensation and load check valve (26) is pushed up and flow goes through the openings in load check valve (26) to bridge passage (35). Oil flows around lift valve stem (18) to work port (32) .
Oil is allowed to flow to the rod end of the lift cylinders. The bucket will lower. Solenoid valves (15) and lift valve stem (18) respond in proportion to the movement of the operator controls.
Oil from the head end of the lift cylinders enters work port (33). The oil flows through energized solenoid valve (10) for drift reduction and exits at tank port (A) to the hydraulic tank.
FLOAT Operation
When the lift control lever is moved to the FLOAT position, pilot oil is sent to the left end of lift valve stem (18). Lift valve stem (18) moves completely to the right. The lift control lever is held in the FLOAT position by a soft detent. The lift valve stem remains in the float position until the bucket reaches the preset kickout position. The lift control valve will then return to the HOLD position.
When the stem moves to the FLOAT position, work port (32) is connected to the tank at port (A) through shifted lift valve stem (18). Complete movement of lift valve stem (18) to the right closes off the flow of pump oil from port (B) to bridge passage (35). Work port (33) continues to be connected to the tank through energized solenoid valve (10) and lift valve stem (18) .
Oil from the rod end of the lift cylinder and the oil from the head end of the lift cylinder drains to the tank. The weight of the lift arm assembly lowers the lift arm assembly to the ground. The lift arm assembly will follow the contour of the ground. Neither the rod end of the lift cylinder or the head end of the lift cylinder are under hydraulic pressure. The lift cylinders can move freely in either direction according to the force on the bucket.
ReferenceFor more information on the operation or the solenoid valves, refer to Systems Operation, "Implement Electronic Control System".
Ride Control Valve
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| Illustration 5 | g02431176 |
Ride control valve (10) 328-4314 Solenoid Valve (Ride Control Accumulator) (14) 252-0737 Solenoid Valve (Ride Control, Lift Cylinder) (16) 4T-7581 Relief Valve (Ride Control) (19) 235-6157 Shuttle Valve (21) 260-8590 Shuttle Valve Load Signal Resolver (23) 194-1723 Check Valve (24) 252-0737 Solenoid Valve (Ride Control On, Off) (36) Work Port to rod end of lift cylinder (37) Work Port to head end of lift cylinder (38) 270-1768 Check Valve (Ride Control) (39) Port to Ride Control Accumulator (A) Tank Port (B) Pump Port | |
Ride control valve (3) is an optional control valve. This function provides dampening for the forces that are produced by the bucket as the machine travels over rough terrain. Ride control valve (3) has three operating modes: AUTO, OFF and SERVICE. Details about the three operating modes of the ride control valve can be found in Systems Operation, "Ride Control System".
Ride control valve (3) contains solenoid valve (24) which is controlled by an on/off output driver from the machine ECM. Solenoid valve (24) works with shuttle valve (19) in order to charge ride control accumulator (7). When accumulator (7) is being charged, check valve (23) allows pump oil to enter ride control valve (3) through shuttle valve (19). Oil exits the ride control valve through port (39) in order to charge ride control accumulator (7) .
When ride control accumulator (7) is not being charged, check valve (23) keeps oil from the circuit from returning to the main hydraulic system. If oil pressure rises above the setting of ride control relief valve (16), the relief valve opens. Excess pressure drains to the hydraulic tank through tank port (A).
Ride control valve (3) also contains solenoid valves (10) and (14). When ride control is activated, solenoid valve (10) allows oil to enter the valve from the rod end of the lift cylinder at port (36). Oil exits the ride control valve at tank port (A). Solenoid valve (14) and check valve (38) allow oil from the lift cylinder head end to mix with oil from accumulator (7) at port (37). Nitrogen gas in ride control accumulator (7) acts as a shock absorber for the lift circuit.
ReferenceThe operation of ride control valve (3) is explained in Systems Operation, "Ride Control System".
ReferenceFor more information on the operation or the solenoid valves, refer to Systems Operation, "Implement Electronic Control System".
Auxiliary Control Valve
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| Illustration 6 | g02431216 |
Auxiliary Control Valve in the OPEN position (11A) 272-2334 Relief Valve (Line) Head end (11B) 272-2334 Relief Valve (Line) Rod end (15) 313-7668 Solenoid Valve (Pilot Proportioning) (20) 260-6736 Valve Stem (Auxiliary) (21) 260-8590 Shuttle Valve Load Signal Resolver (26) Compensation and Load Check Valve (40) Work port to head end of auxiliary cylinder (41) Work port to rod end of auxiliary cylinder (42) Bridge Passage (A) Tank Port (B) Pump Port | |
Auxiliary control valve (4) is an optional control valve. The auxiliary control valve has all of the components that are in the tilt control valve minus the solenoid valve for drift reduction (10). The auxiliary valve controls auxiliary implements such as a logging fork, a side dump bucket, or a multipurpose bucket.
Oil from the implement piston pump flows to the auxiliary control valve at port (B). Auxiliary valve stem (20) is controlled by solenoids (15). Auxiliary valve stem (20) is spring centered with a closed center. Auxiliary valve stem (20) has three positions: CLOSE, HOLD and OPEN.
HOLD Position
Springs keep auxiliary valve stem (20) in the HOLD position when solenoids (15) have not been actuated. Implement pump oil flows to auxiliary control valve (4) at port (B). Stem movement is controlled by actuation of pilot proportioning solenoids (15) that allow oil to flow to either end of auxiliary valve stem (20) .
The position of auxiliary valve stem (20) blocks the oil in both ends of the auxiliary cylinder. The stem keeps the auxiliary cylinder from moving.
CLOSE Position
When the auxiliary control lever is moved to the CLOSE position, pilot oil is sent to the left end of auxiliary valve stem (20). Auxiliary valve stem (20) moves to the right. Implement oil is sent from pump port (B) around auxiliary valve stem (20) to the bottom of compensation and load check valve (26). Compensation and load check valve (26) is pushed up and flow goes through the openings in the load check valve to bridge passage (42). Oil flows around auxiliary valve stem (20) to work port (40) .
Oil is allowed to flow to the head end of the auxiliary cylinder. The auxiliary cylinder extends. Solenoid valves (15) and auxiliary valve stem (20) respond in proportion to the signal that is received from the operator controls.
Oil from the rod end of the auxiliary cylinder enters through work port (41) and exits through tank port (A) to the hydraulic tank.
OPEN Position Operation
When the auxiliary control lever is moved to the OPEN position, pilot oil is sent to the right end of auxiliary valve stem (20). Auxiliary valve stem (20) moves to the left. Implement oil is sent from pump port (B) around auxiliary valve stem (20) to the bottom of compensation and load check valve (26). Compensation and load check valve (26) is pushed up and flow goes through the openings in the load check valve to bridge passage (42). Oil flows around auxiliary valve stem (20) to work port (41) .
Oil flows to the rod end of the auxiliary cylinder. The auxiliary cylinder retracts. Solenoid valves (15) and auxiliary valve stem (20) respond in proportion to the movement of the operator controls.
Oil from the head end of the auxiliary cylinder enters through work port (40) and exits through tank port (A) to the hydraulic tank.
ReferenceFor more information on the operation or the line relief valves, refer to Systems Operation, "Relief Valve (Line)".
ReferenceFor more information on the operation or the solenoid valves, refer to Systems Operation, "Implement Electronic Control System".
Valve Manifold (Inlet)
Valve manifold (5) contains signal duplicating valve (22) and relief valve (25) for load sensing. Signal duplicating valve (22) reduces supply oil to signal pressure.
When a circuit is active, signal duplicating valve (22) duplicates the pressure that is received from load signal resolvers (21). The resolvers send the highest pressure from the active circuits to valve (22). This signal pressure is then sent to the implement piston pump at point (C). The implement piston pump is upstroked in proportion to the signal pressure that is received.
Relief valve (25) for load sensing limits the maximum signal pressure. The valve drains oil that is above maximum signal pressure back to the hydraulic tank at point (D) .
ReferenceFor more information on the operation or the relief valve for load sensing, refer to Systems Operation, "Relief Valve (Load Sensing Signal)".
Valve Manifold (End Cover)
Valve manifold (6) contains solenoid valve (12) for hydraulic lockout and relief valve (27) for margin pressure .
Relief valve (27) for margin pressure receives pump oil from port (B) and load sensing oil from signal duplicating valve (22). Relief valve (27) relieves excess system pressure by draining to the hydraulic tank through tank port (A) .
Solenoid valve (12) for hydraulic lockout is controlled by an output of the implement ECM. The hydraulic lockout switch in the cab provides input to the implement ECM regarding the desired status of the pilot hydraulic system. When the solenoid valve is energized, the pilot hydraulics are enabled. The pilot hydraulics are disabled when the solenoid is de-energized.
ReferenceFor more information on the solenoid valve and switch for hydraulic lockout, refer to Systems Operation, "Implement Electronic Control System".