330D System Operation Hydraulic RENR9584

(1)

RENR 9584 SYSTEMS OPERATION – HYDRAULIC 330D General Information 01/01/2006

General Information 01/01/2006 Main Hydraulic System 01/01/2006

Main Hydraulic Schematic 01/01/2006

Hydraulic Pump Flow and Pressure Control System 01/01/2006

Electronic Control System 01/01/2006 Pilot System 01/01/2006

Pilot Hydraulic System 01/01/2006

Pilot Oil Circuit 01/01/2006

Power Shift Pressure System 01/01/2006

Pilot Control Valve Circuits 01/01/2006

Pressure Switch Circuits 01/01/2006

Straight Travel Valve Circuit 01/01/2006

Swing Brake 01/01/2006 Boom Priority 01/01/2006

Swing Priority 01/01/2006

Automatic Travel Speed Change Valve 01/01/2006

Gear Pump (Pilot) 01/01/2006

Hydraulic Filter (Pilot) 01/01/2006 Relief Valve (Pilot) 01/01/2006

Accumulator (Pilot) 01/01/2006

Solenoid Valve (Hydraulic Lockout) 01/01/2006

Pilot Valve (Joystick) 01/01/2006

Solenoid Valve (Proportional Reducing) - Power Shift System 01/01/2006

Main Pump System 01/01/2006

Main Hydraulic Pump 01/01/2006 Construction 01/01/2006

Operation 01/01/2006

Pump Control (Main Hydraulic) - Main Pump Regulator 01/01/2006

Operation 01/01/2006

Pump Regulator 01/01/2006

Regulator Operation (full stroke position) 01/01/2006

Regulator Operation (minimum stroke position) 01/01/2006

Regulator Operation (standby position) 01/01/2006 Main Control Valve 01/01/2006

Main Control Valve 01/01/2006

Introduction 01/01/2006

Main Control Valve Operation in NEUTRAL Position 01/01/2006 Individual Valve Operation 01/01/2006

Negative Flow Control System 01/01/2006

Introduction 01/01/2006

Fine Control Operation 01/01/2006

Relief Valve (Negative Flow Control) 01/01/2006 Relief Valve (Main) - Heavy Lift 01/01/2006

Limitation Of Pressure In Circuit 01/01/2006

Main Relief Valve 01/01/2006

CLOSED Position (Heavy Lift OFF) 01/01/2006

OPEN Position (Heavy Lift OFF) 01/01/2006 Heavy Lift Operation 01/01/2006

Relief Valve (Line) 01/01/2006

Check Valve (Load) 01/01/2006 Boom System 01/01/2006

Boom Hydraulic System 01/01/2006

Boom Raise (High Speed) 01/01/2006

Boom Raise (Low Speed) 01/01/2006

Boom Priority 01/01/2006

Boom Lower 01/01/2006

Boom Regeneration Valve 01/01/2006

Boom Drift Reduction Valve 01/01/2006

Boom Raise 01/01/2006

Boom Lower 01/01/2006

Stick System 01/01/2006

Stick Hydraulic System 01/01/2006 Stick Out 01/01/2006

Stick In (Fast) 01/01/2006

Stick In (Slow) 01/01/2006

Stick Regeneration Valve 01/01/2006

Stick Unloading Valve 01/01/2006 Stick Drift Reduction Valve 01/01/2006

Stick Out 01/01/2006

(2)

Bucket System 01/01/2006

Bucket Hydraulic System 01/01/2006 Cylinders 01/01/2006

Cylinders (Boom, Stick and Bucket) 01/01/2006 Swing System 01/01/2006

Swing Hydraulic System 01/01/2006

Swing Priority 01/01/2006

Swing Motor 01/01/2006

Pilot Valve (Swing Parking Brake) 01/01/2006 Relief Valve (Swing) 01/01/2006

Oil Makeup (Swing System) 01/01/2006

Relief Valve (Cushion Crossover) - Anti-Reaction Valves 01/01/2006

Solenoid Valve (Fine Swing) 01/01/2006

Swing Drive 01/01/2006

Travel System 01/01/2006

Travel Hydraulic System 01/01/2006 Travel Control 01/01/2006

Forward Travel 01/01/2006

LOW SPEED 01/01/2006

HIGH SPEED 01/01/2006

Automatic Travel Speed Change 01/01/2006 Pilot Valve (Travel) 01/01/2006

Travel Motor 01/01/2006

Travel Parking Brake 01/01/2006

Displacement Change Valve 01/01/2006

Small Displacement Change Operation 01/01/2006 Large Displacement Change Operation 01/01/2006

Travel Counterbalance Valve 01/01/2006

Counterbalance Valve Operation During Level Travel 01/01/2006

Counterbalance Valve Operation During Slope Travel 01/01/2006

Operation Of Travel Crossover Relief Valves During Machine Stop 01/01/2006 Travel Parking Brake Operation 01/01/2006

Oil Makeup (Travel System) 01/01/2006

Control Valve (Straight Travel) 01/01/2006

Final Drive 01/01/2006

Operation 01/01/2006 Swivel 01/01/2006

Return System 01/01/2006

Return Hydraulic System 01/01/2006

Check Valve (Return Makeup) - Slow Return Check Valve 01/01/2006

Bypass Valve (Return) - Bypass Check Valve 01/01/2006

Hydraulic Tank and Filter 01/01/2006

Oil Filter (Return) - Case Drain Filter 01/01/2006 Hydraulic Oil Cooler 01/01/2006

Reference 01/01/2006

(3)

Systems Operation

330D Excavator Hydraulic System

General Information

SMCS - 4000; 4250; 4265; 4284; 4300; 4801; 5050

Reference: For testing and adjusting of the hydraulic system, refer to Testing and Adjusting,

"Excavator Hydraulic System" for your machine.

Reference: For systems operation of the electronic control unit and electronic system, refer to

Systems Operation/Testing and Adjusting, "Excavator Engine and Pump Control" for your machine.

Reference: For more information on specifications with illustrations, refer to Specifications,

"Excavator Machine System Specifications" for your machine.

Reference: For more information on the hydraulic schematics, refer to Schematic, "Excavator

Hydraulic System" for your machine.

Reference: For more information on electrical schematics, refer to Schematic, "Excavator Electrical

System" for your machine.

Shutdown

Previous Screen Product: EXCAVATOR

Model: 330D L EXCAVATOR B6H

Configuration: 330D L Excavator B6H00001-UP (MACHINE) POWERED BY C9 Engine

Media Number -RENR9584-00 Publication Date -01/01/2006 Date Updated -01/02/2006

i01584866

Private Network For SIS Licensees.

(4)

Main Hydraulic System

SMCS - 5050; 5051; 5069; 5117; 5472

Main Hydraulic Schematic

Shutdown

i02459525

Illustration 1 g01227433

(1) Swing motor (2) Left travel motor

(5)

Hydraulic Pump Flow and Pressure Control System

(32) Idler pump (view from shaft end)

(33) Pilot pump

(34) Slow return check valve (35) Bypass check valve

(36) Pressure sensor (idler pump)

(37) Proportional reducing valve (power shift pressure) (38) Oil cooler

(39) Return filter (40) Hydraulic tank (41) Gear pump (fan motor) (42) Relief valve (fan pump) (43) Fan motor (hydraulic oil cooler)

Pump compartment (26) Drive pump (32) Idler pump

(37) Proportional reducing valve (power shift pressure) (44) Delivery line (idler pump)

(6)

(3) Right travel motor (4) Stick cylinder

(5) Travel brake valve (left) (6) Travel brake valve (right) (7) Bucket cylinder

(8) Boom cylinder (9) Swivel

(10) Pilot control valve (travel) (11) Stick drift reduction valve (12) Main control valve (13) Boom drift reduction valve (14) Pressure switch

(15) Pressure switch

(16) Pilot control valve (swing and stick) (17) Pilot control valve (boom and bucket) (18) Main relief valve

(19) Pressure switch (20) Accumulator

(21) Reducing valve (boom priority mode or swing priority mode) (22) Pressure sensor (drive pump)

(23) Swing brake solenoid valve (24) Valve

(25) Solenoid valve (hydraulic lockout) (26) Drive pump (view from shaft end) (27) Travel speed solenoid valve (28) Pilot oil manifold

(29) Drain filter (30) Pilot relief valve (31) Pilot filter

(7)

This machine is driven and controlled by the following systems.

z The main hydraulic system controls the cylinders, the travel motors and the swing motor. z The pilot hydraulic system supplies oil to the main pumps, the main control valve, the swing

brake and the travel motors.

z The electronic control system controls the outputs of the engine and pump.

z The hydraulic oil cooling system provides oil to the fan motor in order to cool the hydraulic

oil.

The main hydraulic system delivers oil flow from idler pump (32) and drive pump (26) in order to control the following components: bucket cylinder (7), stick cylinder (4), boom cylinders (8), right travel motor (3), left travel motor (2) and swing motor (1).

Idler pump (32) and drive pump (26) are bent axial piston type pumps. The performance of both pumps is equal.

Drive pump (26) is directly connected to the engine by a flexible coupling. The drive pump delivers oil to the left control valve body (46) of the main control valve. Idler pump (32) is mechanically connected to the drive pump through gears. The idler pump delivers oil to the right control valve body (45) of the main control valve. Gear type pilot pump (33) supplies oil to the pilot hydraulic system. Gear type pilot pump (33) is mechanically connected to idler pump (32) through gears. Gear pump (41) supplies oil to the oil cooling system. Gear pump (41) is mechanically connected to the engine through gears. All engine output is used to drive these four pumps.

As the load pressure increases during working conditions, the main pumps increase the delivery pressure and the pumps decrease the flow rate. The hydraulic horsepower remains constant even though the delivery pressure and the flow rates change. The hydraulic horsepower is approximately

Main control valve (18) Main relief valve (45) Right control valve body (46) Left control valve body

(8)

identical to the engine horsepower.

When no work is being performed, pump oil flows through main control valve (12) and into

hydraulic tank (40). The main control valve sends a negative flow control signal to each main pump regulator in order to destroke the pump to the minimum output flow.

If an operation is being performed, main control valve (12) directs pump oil to the respective cylinders (boom, bucket, and stick) and/or motors (swing and travel). Main control valve (12) contains numerous valve stems, passages, check valves, and orifices in order to carry out a single operation or a combined operation. The working pressure of the main hydraulic system is regulated by main relief valve (18).

The pilot hydraulic system receives oil flow from pilot pump (33). The pilot hydraulic system controls the following functions.

1. The pilot hydraulic system controls the operation of the implement control valves.

Pilot oil flows from pilot pump (33) through pilot manifold (28). The pilot oil then flows to the pilot control valves for machine operation (implement operations, swing operations and travel operation). These pilot control valves are activated by the joysticks and the travel

levers/pedals.

When joystick (48), joystick (49), left travel lever/pedal (50) and/or right travel lever/pedal

Cab

(47) Monitor panel

(48) Joystick (stick and swing) (49) Joystick (boom and bucket) (50) Left travel lever/pedal (51) Right travel lever/pedal (52) Straight travel pedal (53) Engine speed dial

(9)

(51) are moved from the NEUTRAL position, the pilot oil flows through the pilot control valves to the corresponding spools at the main control valve (12) .

The pilot pressure oil at that end of the valve spool forces the valve spool to shift. The pilot oil on the other end of the valve spool drains to the hydraulic tank. When the valve spool shifts, oil is then delivered from idler pump (32) or drive pump (26) to the cylinders and motors. Thus, pilot oil drives each system of the main control valve.

2. The pilot hydraulic system controls the output flow of the main pumps.

During machine operation, pilot pressure is sent to the main pump regulators as a signal pressure. This signal pressure is called power shift pressure. The engine and pump controller receives input signals from various components on the machine. The engine and pump

controller processes the input signals. The engine and pump controller then sends an electrical signal to proportional reducing valve (37) at the idler pump regulator in order to regulate the power shift pressure. The power shift pressure controls the output flow of idler pump (32) and drive pump (26). Power shift pressure adjusts the output flow of the main pumps in accordance with the engine speed. For more information concerning power shift pressure, refer to Systems Operation, "Pilot Hydraulic System".

3. The pilot hydraulic system generates signal pressure in order to perform the following operations.

a. Pilot signal pressure activates the Automatic Engine Speed Control (AEC) system. This causes functions to automatically reduce the engine speed when no hydraulic operation is called for.

b. Pilot signal pressure releases the swing parking brake.

c. Pilot signal pressure will automatically change the travel speed to either HIGH or LOW in accordance with the hydraulic system load.

d. Pilot signal pressure operates the straight travel control valve. This maintains straight travel during the operation of an implement.

e. Pilot signal pressure controls the operation of the valves that can be used during a loading operation or a trenching operation.

For more information concerning the pilot hydraulic system, refer to Systems Operation, "Pilot Hydraulic System".

(10)

Electronic Control System

SMCS - 1900

Shutdown

i02349560

(1) Machine ECM (2) Engine speed dial

(11)

(3) Switch panel

(4) Clench pressure sensor (attachment) (5) Manual low idle switch

(6) Implement pressure switch (7) Swing pressure switch (8) Right travel pressure switch (9) Left travel pressure switch (10) Straight travel pressure switch (11) Right pump pressure sensor (12) Left pump pressure sensor (13) Fuse panel

(14) viscous clutch (15) Fan speed sensor (16) Engine

(17) Main pumps (18) Engine speed pickup (19) Battery

(20) Engine start switch (21) Backup switch (22) Monitor

(23) Heavy lift solenoid valve (24) Straight travel solenoid valve (25) Travel speed solenoid valve (26) Swing brake solenoid valve (27) Hydraulic lockout solenoid

(28) Flow limiter valve (attachment pump) (29) Pressure switch (attachment pump) (30) Attachment pedal pressure switch (Left) (31) Attachment pedal pressure switch (Right)

(12)

The electronic control system consists of monitor (12) in the cab and the machine ECM (1) that is located in the compartment behind the cab. The electronic control system controls the engine speed

(32) Proportional reducing valve for auxiliary hydraulics (33) Power shift solenoid valve

(1) Machine ECM

(13)

and the pumps through the machine ECM.

Machine ECM (1) receives input signals from various components on the machine. The machine ECM continuously monitors the input signals in order to control the output flow rate of the main pumps, engine speed and various components of the machine hydraulic systems.

The machine ECM has the following three major functions.

z The electronic control system controls the output flow rate of the main pumps. The machine ECM sends an electrical signal to the power shift solenoid that is based on engine speed and the position of the engine speed dial. This allows the main pumps to supply the optimum output that matches the hydraulic load to the machine and the engine speed. When a large load is placed on the machine, the system allows the pumps to destroke. The system utilizes the available maximum engine horsepower.

z The electronic control system controls the engine speed. This is called Automatic Engine Speed Control (AEC). When there is a very small load condition or no load condition, the system automatically decreases the engine speed. The AEC system is designed to reduce fuel consumption and noise.

z The electronic control system controls various components of the machine hydraulic systems. The machine ECM sends output signals to the swing brake solenoid valve, the travel speed solenoid valve and the straight travel solenoid.

Note: If a problem occurs in the electronic control system, temporary operation of the machine is

possible by use of the backup switches that are located in the cab. For more information concerning the backup system, refer to Operation and Maintenance Manual, "Backup Controls".

Reference: For more information concerning the operation of the electronic control system, refer to

Systems Operation/Testing and Adjusting, "Engine and Pump Electronic Control System".

(14)

Pilot Hydraulic System

SMCS - 5050-PS

Shutdown

i02462061

(1) Swing brake

(2) Displacement change valve (left travel motor) (3) Displacement change valve (right travel motor)

(15)

(4) Line (pilot oil from swing brake solenoid valve) (5) Travel pilot control valve

(6) Pilot line (BOOM LOWER)

(7) Pilot line (boom drift reduction valve) (8) Pilot line (STICK IN)

(9) Pilot line (stick drift reduction valve) (10) Stick drift reduction valve

(11) Main control valve (12) Boom drift reduction valve (13) Solenoid valve (straight travel)

(14) Pilot line (pilot pressure to left travel pressure switch) (15) Pilot line (pilot oil to travel pilot control valve) (16) Right travel control valve

(17) Boom I control valve (18) Straight travel control valve (19) Travel pressure switch (left)

(20) Pilot line (pilot pressure to right travel pressure switch) (21) Travel pressure switch (right)

(22) Pilot line (pilot oil to pilot control valve for the stick and swing) (23) Pilot line (pilot oil to pilot control valve for the boom and bucket) (24) Left travel control valve

(25) Pilot control valve for stick and swing (26) Pilot control valve for boom and bucket (27) Variable swing priority valve

(28) Pilot line (STICK OUT) (29) Pilot line (STICK IN) (30) Pilot line (SWING RIGHT) (31) Pilot line (SWING LEFT) (32) Pilot line (BUCKET CLOSE)

(16)

(33) Pilot line (BOOM RAISE) (34) Pilot line (BOOM LOWER) (35) Pilot line (BUCKET OPEN)

(36) Pilot line (pilot oil from boom pilot control valve) (37) Pilot line (BOOM RAISE)

(38) Pilot line (pilot oil to the pressure reducing valve for boom priority) (39) Pilot line (pilot pressure to implement/swing pressure switch) (40) Implement/swing pressure switch

(41) Pilot line (pilot pressure to displacement change valves)

(42) Pilot line (pilot oil to pressure reducing valve for swing priority) (43) Pilot line (pilot oil to pilot control valves)

(44) Pilot line (pilot oil to straight travel control valve) (45) Swing brake solenoid valve

(46) Valve (hydraulic lockout)

(47) Pressure reducing valve for swing priority (48) Pressure reducing valve for boom priority (49) Drive pump

(50) Passage (power shift pressure) (51) Pilot manifold

(52) Travel speed solenoid valve (53) Passage

(54) hydraulic lockout valve (55) Passage

(56) Passage (57) Passage (58) Idler pump (59) Pilot pump

(60) Pilot line (pilot oil flow to pilot oil manifold) (61) Pilot filter

(17)

Pilot Oil Circuit

The pilot circuit pressure is limited by pilot relief valve (64) .

The oil delivery from pilot pump (59) performs the following main functions.

z Create pilot oil pressure in order to control the output flows of the main pumps.

(62) Passage (power shift pressure)

(63) Proportional reducing valve (power shift pressure) (64) Pilot relief valve

(65) Passage

(66) Pilot line (pilot oil flow from pilot pump to pilot oil filter) (67) Pilot line (pilot oil flow to pump regulators)

Ports and solenoids at the pilot manifold (45) Swing brake solenoid valve (46) Valve (hydraulic lockout) (52) Travel speed solenoid valve (54) hydraulic lockout valve

(18)

z Provide pilot oil pressure to the pilot control valves for implements, swing and travel in order to perform machine operations.

z Create pilot oil pressure in order to automatically operate the control devices.

The pilot circuit is classified into the following circuits and each circuit performs one of the above functions.

z Power shift pressure system

z Pilot control valve circuit z Pressure switch circuits z Straight travel valve circuit

z Swing brake z Boom priority z Swing priority

z Automatic travel speed change

(19)

During machine operation, machine ECM (68) receives input signals from the following components:

z Engine speed dial (70)

(49) Drive pump (58) Idler pump

(63) Proportional reducing valve (PS pressure) (59) Pilot pump

(68) Machine ECM (69) Monitor

(70) Engine speed dial

(71) Drive pump pressure sensor (72) Idler pump pressure sensor

(73) Engine speed pickup (flywheel housing) (74) Pump (fan motor)

(20)

z Engine speed pickup (73) that is located on the flywheel housing

z Idler pump pressure sensor (71) z Drive pump pressure sensor (72)

z Monitor in the cab (69)

The machine ECM (68) continually monitors all of the input signals. The input signals are processed by the machine ECM and an output signal is sent to proportional reducing valve (63) at the pump regulator. The proportional reducing valve assists in controlling the output flow of idler pump (58) and drive pump (49) .

The oil delivery from pilot pump (59) flows through the pilot filter to proportional reducing valve (63) at the pump regulator. The electrical signal that is sent from machine ECM (68) causes proportional reducing valve (63) to regulate the pilot pressure to a reduced pressure. This reduced pressure is called power shift pressure (PS). The proportional reducing valve sends the reduced pilot oil pressure through the idler pump regulator and through the drive pump regulator. The output flow of idler pump (58) and drive pump (49) is controlled in accordance with the power shift pressure. The power shift pressure is used to regulate the maximum allowable hydraulic pump output.

The output signal that is sent from the machine ECM to the proportional reducing valve will change when the machine ECM detects a change in any of the input signals. The power shift pressure that is sent to the regulators at the idler pump and the drive pump will change in order to regulate the maximum allowable hydraulic pump output. The desired engine speed is maintained.

A decrease in engine speed increases the power shift pressure. An increase in power shift pressure causes destroke condition of the idler pump and the drive pump. The maximum allowable hydraulic power output is decreased.

An increase in engine speed decreases the power shift pressure. A decrease in power shift pressure causes an upstroke condition of the idler pump and the drive pump. The maximum allowable hydraulic power output is increased.

Note: For more information concerning the operation of the machine ECM, refer to Systems

Operation/Testing and Adjusting, "Electronic Control System".

Pilot Control Valve Circuits

Oil from pilot pump (59) flows through pilot line (66), pilot filter (61) and pilot line (60) to pilot manifold (51). When the control lever for the hydraulic lockout is shifted to the UNLOCKED

position, the machine ECM energizes the hydraulic lockout valve (54). The pilot oil then shifts valve (46). The pilot oil now flows through valve (46) and pilot line (43). The pilot oil now flows to pilot control valves (5), (25) and (26) for implements, swing and travel in order to perform machine operations. When the joysticks and/or travel levers/pedals are moved, the pilot oil flows to main control valve (11) in order to control the machine functions.

(21)

When joystick (25) and/or joystick (26) are operated, the pilot control valves send pilot pump oil through the pilot lines to pilot ports at the main control valve in order to shift the spools in the main control valve. Refer to Illustration 4 and Table 1 for the location of the pilot lines and machine operations.

Pilot oil from the pilot control valves flows through pilot lines to the ports on the bottom of the main control valve in order to perform the opposite operation.

The following example is given for the BOOM LOWER operation and the BOOM RAISE operation. Machine operations for a stick operation, bucket operation, travel operation and swing operation are accomplished in the same manner as the boom operation.

When the joystick for the boom is moved to the BOOM RAISE position, pilot oil from pilot control valve (26) flows through pilot line (37) to boom I control valve (17). The pilot pressure shifts the boom I control valve. The oil delivery from the idler pump flows to the head end of the boom cylinders in order to perform the BOOM RAISE operation.

When the joystick for the boom is moved to the BOOM LOWER position, pilot oil from pilot

Pilot lines at the main control valve (top view)

Table 1

Pilot line Control Valve Machine Operation

(76) Boom I control valve BOOM LOWER

(77) Bucket control valve BUCKET CLOSE

(78) Swing control valve SWING LEFT

(79) Boom II control valve BOOM RAISE

(80) Stick II control valve STICK IN

(81) Right travel control valve REVERSE RIGHT TRAVEL (82) Left travel control valve REVERSE LEFT TRAVEL

(22)

control valve (26) flows through pilot line (6) to boom I control valve (17). The pilot pressure shifts the boom I control valve. The pilot oil also flows through pilot line (7) in order to open boom drift reduction valve (12). The return oil from the head end of the boom cylinders flows through the boom drift reduction valve and the boom I control valve to the hydraulic tank. The BOOM LOWER

operation is now performed.

Pressure Switch Circuits

Pressure switches (19) and (21) are connected to travel pilot control valve (5). Pressure switch (40) is connected to pilot control valve (25) and pilot control valve (26). When all of the joysticks and/or travel levers/pedals are in the NEUTRAL position, the pilot oil pressure to the pressure switches is low. Pressure switches (19), (21) and (40) are OFF. The machine ECM recognizes the OFF condition of all of the pressure switches. The AEC system is activated in order to lower the engine rpm.

If any of the joysticks and/or travel levers/pedals are moved from the NEUTRAL position, the increased pilot oil pressure is sent to the pressure switches. If pressure switch (19), (21) and/or (40) is ON, the machine ECM activates the AEC system in order to increase the engine rpm.

Straight Travel Valve Circuit

When a swing operation and/or implement operation is performed during a travel operation, the increase of pilot pressure in pilot line (39) activates implement/swing pressure switch (40). The implement/swing pressure switch sends an electrical signal to the machine ECM. The machine ECM energizes straight travel solenoid (13). Pilot pressure now activates straight travel control valve (18). The straight travel control valve maintains straight travel even though there is a swing operation or an implement operation during travel. For more information concerning the operation of the straight travel control valve, refer to Systems Operation, "Control Valve (Straight Travel)".

Swing Brake

When the control lever for the hydraulic lockout is placed in the UNLOCKED position, pilot oil in passage (57) flows through valve (46) and passage (53) to swing brake solenoid valve (45). When any of the joysticks are moved from the NEUTRAL position, the increase of pilot pressure in pilot line (39) activates implement/swing pressure switch (40). The implement/swing pressure switch sends an electrical signal to the machine ECM. An electrical signal from the machine ECM energizes the swing brake solenoid valve (45). Pilot oil in line (4) flows to swing brake (1). This oil releases the swing brake. For more information concerning the operation of the swing brake, refer to Systems Operation, "Pilot Valve (Swing Brake)".

Boom Priority

During combined operations of BOOM RAISE and STICK IN, the pilot oil pressure in pilot line (36) and pilot line (38) activates the pressure reducing valve for boom priority. The pressure reducing valve for boom priority allows priority flow to the head end of the boom cylinders during these combined hydraulic operations by disabling the stick II control valve. For more information concerning the pressure reducing valve for boom priority, refer to Systems Operation, "Boom Hydraulic System".

Swing Priority

(23)

for swing priority (47). The pressure reducing valve for swing priority shifts. The pilot oil flow in pilot line (42) from pilot oil manifold (51) is blocked by the pressure reducing valve for swing priority. Most of the drive pump delivery flow goes to the swing motor. For more information concerning the pressure reducing valve for swing priority, refer to Systems Operation, "Swing Hydraulic System".

Automatic Travel Speed Change Valve

Pilot oil in passage (56) flows to travel speed solenoid valve (52). When the travel speed switch on the right console is set at the HIGH SPEED position, the travel speed solenoid valve opens. This allows pilot oil to flow through travel speed solenoid valve (52) and through line (41). The oil then flows to the displacement change valve for the left travel motor (2) and the displacement change valve for the right travel motor (3). As the displacement change valve operates, the travel speed is maintained at the HIGH SPEED position.

When the travel speed switch on the right console is set at the HIGH SPEED position, the pressure sensors for the pump delivery pressure control the travel speed in accordance with the travel load. For example, low speed during a high load condition and high speed during a low load condition. For more information concerning the operation of the displacement change valves, refer to Systems Operation, "Displacement Change Valve".

(24)

Gear Pump (Pilot)

SMCS - 5073; 5085

The pilot pump is a gear type pump that supplies oil flow to the pilot system. The pilot pump is located inside the main pump compartment and mounted externally to the main pump. The pilot pump shaft is mechanically connected to the idle pump shaft. The pump delivery rate with load is approximately 34 L/min (9.0 US gpm).

Shutdown

i02467491

Pilot pump

(25)

Hydraulic Filter (Pilot)

SMCS - 5068; 5092

The oil delivery from the pilot pump flows through pilot oil filter (1) and into the components in the pilot system.

Shutdown

i02467567

(26)

Relief Valve (Pilot)

SMCS - 5072

Pilot relief valve (2) is located on the mounting base for the pilot oil filter. The pilot relief valve limits the pressure in the pilot system. The pilot relief valve setting is adjustable.

The pilot oil flows from the pilot pump to inlet port (1). When the pressure in the pilot oil system reaches the pressure setting of pilot relief valve (2), part of the pilot oil flow is returned to the hydraulic tank through port (3). The pressure of the pilot system oil in outlet lines (4) is equal to the pressure setting of the pilot relief valve.

Reference: For more information concerning the pilot relief valve setting, refer to Testing and

Adjusting, "Relief Valve (Pilot) - Test and Adjust".

Shutdown

i01630729

(1) Inlet port (oil flow from pilot pump) (2) Pilot relief valve

(3) Port (oil flow to hydraulic tank) (4) Outlet lines (regulated pilot oil pressure)

(27)

(28)

Accumulator (Pilot)

SMCS - 5077

The accumulator stores pilot pressure oil for use at the main control valves. During some operations, the pilot system needs more oil because there is insufficient flow from the pilot pump. Accumulator (5) will provide pilot pressure oil to the pilot system when the pilot pump flow is inadequate.

Insufficient supply of pilot oil flow to the pilot system may be caused by the following two reasons:

z Implements are lowered while the engine is stopped and oil supply to the main control valves

is stopped. z Combined operations Shutdown Previous Screen Product: EXCAVATOR Model: 330D L EXCAVATOR B6H

i02467598

(5) Accumulator

(16) Line (pilot oil from pilot oil manifold) (17) Mounting block

(29)

Filter element (2) in pilot oil filter (1) removes contaminants from the pilot oil.

If the pilot oil is extremely cold or if the flow of pilot oil through filter element (2) becomes

restricted by contaminants, the oil bypasses filter element (2) through bypass relief valve (3). Bypass relief valve (3) is built into the base for the pilot oil filter.

(1) Pilot oil filter (2) Filter element (3) Bypass relief valve

(30)

Illustration 2 g01230637 Accumulator

(5) Accumulator

(16) Line (pilot oil flow from pilot oil manifold to the mounting block for the accumulator) (17) Mounting block

(18) Passage (19) Inlet port

(20) Pressure oil chamber (21) Vessel (22) Bladder (23) Gas chamber (24) Passage (25) Passage (26) Passage

(31)

Pilot oil from the pilot filter enters inlet port (27) of the pilot oil manifold. Pilot oil flows through passage (28) and opens check valve (29). Pilot oil now flows through passages (24) and (26) to the pilot control valves (joysticks and travel levers/pedals).

The pilot oil also flows through passage (25) and line (16) to the mounting block for the accumulator. The pilot oil now flows through passage (18) and inlet port (19) into pressure oil chamber (20). The pilot oil acts against bladder (22) and the nitrogen gas in gas chamber (23) is compressed. Check valve (29) prevents a backflow of the stored oil in the accumulator. The stored oil is used for solely operating the stems of the main control valve.

(27) Inlet port (pilot oil manifold) (28) Passage

(29) Check valve

(32)

Solenoid Valve (Hydraulic Lockout)

SMCS - 5479

Shutdown

i02353810

Pilot oil manifold (1) Pilot oil manifold

(33)

(2) Solenoid valve for hydraulic lockout

Cab

(3) Hydraulic lockout lever (LOCKED position)

Cab

(34)

Limit switch (6) and plunger (4) are located on a bracket with hydraulic lockout lever (3). The limit switch is activated by hydraulic lockout lever (3) .

When hydraulic lockout lever (3) is shifted to the LOCKED position, solenoid valve (2) of pilot oil manifold (1) is not energized. Pilot oil is not supplied to the pilot control valves. Thus when the joysticks and/or the travel levers/pedals are operated, the cylinders or the motors are not activated also.

The engine will not start unless hydraulic lockout lever (3) is in the LOCKED position. If some one unexpectedly operates the machine, the machine will not operate.

When hydraulic lockout lever (3) is placed in the UNLOCKED position, solenoid valve (2) is energized and pilot oil passes through the solenoid valve. Pilot oil now flows to the pilot control valves.

(3) Hydraulic lockout lever (4) Plunger

(5) Bar

(35)

When hydraulic lockout lever (3) is placed in the UNLOCKED position, plunger (4) of limit switch (6) is depressed by control lever (3). Limit switch (6) is in the ON state.

The hydraulic lockout valve (2) consists of solenoid (7) and control valve (10). When hydraulic lockout lever (3) is in the UNLOCKED position, solenoid (7) controls valve (10). When solenoid (7) is energized, spool (9) moves in a downward direction against the force of spring (8). Passage (12)

Partial diagram of solenoid valve (hydraulic lockout) (UNLOCKED circuit) (2) Solenoid valve for hydraulic lockout

(7) Solenoid (8) Spring (9) Spool (10) Control valve (11) Passage (12) Passage (13) Passage

(14) Passage (return oil)

(15) Passage (pilot oil to swing brake solenoid valve) (16) Swing brake solenoid valve

(17) Pilot oil flow to pilot valves (joysticks) (18) Valve (hydraulic lockout)

(36)

opens. Pilot pressure oil from passage (13) flows through passage (11) to valve (18). The spool in valve (18) moves in a downward direction. Pilot pressure oil in passage (19) flows through valve (18). Pilot oil is now delivered through passage (15) to swing brake solenoid valve (16). Pilot pressure oil in passage (19) is also delivered to the pilot control valves (joysticks and travel levers/pedals) through line (17).

Partial drawing of solenoid valve (hydraulic lockout) (LOCKED position) (1) Solenoid valve for hydraulic lockout

(7) Solenoid (8) Spring (9) Spool (11) Passage (12) Passage (13) Passage

(14) Passage (return oil) (20) Passage

(37)

When hydraulic lockout lever (3) is moved to the LOCKED position, plunger (4) of limit switch (6) is not depressed by control lever (3). Limit switch (6) is in the OFF state.

When hydraulic lockout lever (3) is in the LOCKED position, solenoid (7) is not energized. Spool (9) is forced upward by spring (8). Passage (20) opens and passage (12) closes. Passage (13) is not open to passage (11). Pilot oil supply to line (17) is stopped. Pilot oil supply to the pilot control valves (joysticks and travel levers/pedals) is blocked. The cylinders and the motors can not be activated.

(38)

Pilot Valve (Joystick)

SMCS - 5705-V4

When joystick (1) and/or joystick (2) are operated, the pilot control valves send pilot pump oil through the pilot lines to pilot ports at the main control valve in order to shift the spools in the main control valve.

Shutdown

i02354379

Cab

(1) Joystick (left) (2) Joystick (right)

(39)

Pilot control valve (1) Joystick (2) Rod (3) Return passage (4) Passage (5) Spool (6) Plate (7) Rod (8) Spring (9) Seat (10) Seat (11) Spring (12) Spring

(40)

When joystick (1) is moved to the right, plate (6) tilts to the right. Plate (6) pushes down on rod (7). Seat (10) moves down against the force of metering spring (11) and spring (12). The force of metering spring (11) shifts spool (16) downward. Passage (15) opens. The pilot oil flows through passage (20), passage (18), passage (15), and port (19) to the main control valve. The pilot oil pressure shifts the spool of the main control valve. This enables the implement operation or swing operation.

The return pilot oil at the opposite end of the spool in the main control valve returns to the pilot control valve through port (17). Since rod (2) is not pushed down by plate (6), return passage (3) is open and passage (4) is closed. The return pilot oil flows through return passage (3), return chamber (13), and port (21) to the hydraulic tank.

The force of metering spring (11) varies with the position of the joystick. Since spool (16) is moved by the force of metering spring (11), the pilot oil pressure that flows through passage (15) to the main control valve directly corresponds with the position of the joystick. Spool modulation in the main control valve directly corresponds with the amount of movement of the joystick.

When the joystick is moved slightly from the NEUTRAL position, metering spring (11) moves spool (16) slightly. Low pilot oil pressure is sent to the spool of the main control valve. The main control valve spool shifts a slight amount. The volume of oil delivery to the cylinders and/or motors is small. The speed of the cylinders and/or motors is slow. As the joystick is moved farther from the

NEUTRAL position, the force of metering spring (11) on spool (16) increases. The pilot oil pressure that is sent to the main control valve increases. The spool in the main control valve shifts farther and the speed of the cylinders and/or motors increases. Thus, cylinder speed and motor speed is

controlled by the amount of movement and the position of the joystick.

When the joystick is moved slightly from the NEUTRAL position, only metering spring (11) acts on spool (16). Fine control of the cylinders and/or motors is accomplished since the pilot oil pressure that is sent to the main control valve is decreased. As the joystick is moved farther from the NEUTRAL position, the bottom of rod (7) comes in contact with spring (8). Now, the combined force of metering spring (11) and spring (8) act on spool (16). The pilot oil pressure increases rapidly. The cylinders and/or motors respond more rapidly.

When the joystick is released, the joystick will return to the NEUTRAL position due to the force of spring (12).

(13) Return chamber (14) Return passage (15) Passage (16) Spool

(17) Port (return pressure to valve) (18) Passage (pilot supply pressure) (19) Port (reduced pressure to valve) (20) Port (pilot supply)

(41)

(42)

Solenoid Valve (Proportional Reducing) - Power Shift System

SMCS - 5479

The proportional reducing valve for the power shift pressure is located on the main pump housing. The proportional reducing valve is a solenoid operated control valve. The proportional reducing valve receives supply oil from the pilot pump. The solenoid receives a pulse width modulated signal (PWM signal) from the machine ECM. The PWM signal that is sent from the machine ECM causes the proportional reducing valve to regulate the pilot pressure to a reduced pressure. This reduced pressure is called power shift pressure (PS). The proportional reducing valve sends the reduced pilot oil pressure to the regulators at the idler pump and the drive pump. The output flow of the idler pump and the drive pump is controlled in accordance with the power shift pressure. The power shift

pressure is used to control the maximum allowable hydraulic pump output.

Shutdown

i02478040

Proportional reducing valve (power shift solenoid) (1) Solenoid

(3) Valve body (9) Line (pilot oil flow)

(43)

Illustration 2 g01237695 Proportional reducing valve (increase in PWM signal)

(1) Solenoid (2) Spring (3) Valve body (4) Spool

(5) Passage (return oil flow)

(6) Passage (power shift pressure to pump regulators) (7) Spool chamber

(44)

A decrease in engine speed causes an increase in power shift pressure and a decrease in pump flow. While the engine is operating, the machine ECM senses a decrease in engine speed. A decrease in engine speed causes the machine ECM to increase the PWM signal that is sent to solenoid (1). The magnetic force of the solenoid increases. As the magnetic force of the solenoid becomes greater than the force of spring (2), spool (3) moves in a downward direction against the force of the spring. The downward movement of spool (3) blocks the flow of oil from passage (6) to passage (5). Pilot oil in line (9) now flows through passage (8), into spool chamber (7) and into passage (6) at a reduced pressure (power shift pressure). The increased power shift pressure in passage (6) acts on the idler pump regulator and the drive pump regulator. The idler pump and the drive pump destroke as a result of an increase in power shift pressure.

Proportional reducing valve (decrease in PWM signal) (1) Solenoid

(45)

An increase in engine speed causes a decrease in power shift pressure and an increase in pump flow. While the engine is operating, the machine ECM senses an increase in engine speed. An increase in engine speed causes the machine ECM to decrease the PWM signal that is sent to solenoid (1). The magnetic force of the solenoid decreases. As the force of spring (2) becomes greater than the magnetic force of the solenoid, spool (3) moves in an upward direction. The upward movement of spool (3) blocks the flow of pilot oil from passage (8). Power shift pressure oil in passage (6) now drains into spool chamber (7) and into passage (5). The decreased power shift pressure in passage (6) that is acting on the idler pump regulator and the drive pump regulator causes the idler pump and the drive pump to move to an upstroke position. The idler pump and the drive pump upstroke as a result of a decrease in power shift pressure.

ReferenceFor more information concerning power shift pressure (PS), refer to Systems Operation,

"Pilot Hydraulic System".

(2) Spring (3) Valve body (4) Spool

(5) Passage (return oil flow)

(6) Passage (power shift pressure to pump regulators) (7) Spool chamber

(8) Passage (pilot oil flow)

(46)

Main Hydraulic Pump

SMCS - 5070-MV

Construction

Shutdown Previous Screen Product: EXCAVATOR Model: 330D L EXCAVATOR B6H

(47)

Illustration 1 g01238113 Main pumps

(1) Port (negative flow control pressure for drive pump) (2) Outlet port (pilot pressure)

(3) Idler pump

(4) Outlet port (idler pump)

(5) Inlet port (supply oil from the hydraulic tank) (6) Proportional reducing valve (power shift pressure) (7) Port (negative flow control pressure for idler pump)

(48)

The main pump consists of drive pump (8) and idler pump (3). The drive pump and the idler pump are contained in an integral housing. Both pumps are variable displacement piston pumps. The drive pump and the idler pump are identical in construction and operation.

Supply oil from the hydraulic tank enters inlet port (5). The single inlet port is common to main pumps (8) and (3) as well as pilot pump (11). The drive pump delivers oil through outlet port (9). The idler pump delivers oil through outlet port (4). The pilot pump delivers oil through outlet port (2) .

Both the drive pump and the idler pump have a regulator as part of the pump control system. The flow control of the pumps is performed by the operation of the regulators. The control system is identical for both pumps.

Proportional reducing valve (6) for the power shift pressure is located on the head of the main pump. The proportional reducing valve is controlled by the machine ECM. The proportional reducing valve controls the signal from the power shift pressure for both the drive pump and the idler pump.

Negative flow control pressure from the main control valve enters the drive pump regulator at port (1). Negative flow control pressure from the main control valve enters the idler pump regulator at port (7) .

Case drain oil from the pump housing flows from port (15) to the case drain filter.

Operation

(8) Drive pump

(9) Outlet port (drive pump) (10) Housing

(11) Pilot pump

(14) Port (power shift pressure) (15) Case drain port

(49)

Illustration 2 g01238115 Main pumps (sectional view)

(3) Idler pump (8) Drive pump (11) Pilot pump (16) Gear (17) Drive shaft (18) Drive shaft (19) Gear (20) Swashplate (21) Plate (22) Retainer (23) Piston slipper (24) Piston (25) Barrel (26) Port plate (27) Passage

(50)

Gear (19) of drive shaft (18) meshes with gear (16) of drive shaft (17). Gear (16) and gear (17) have the same number of teeth. Drive shaft (18) of drive pump (8) is connected to the engine by a

coupling. When the engine is running, drive shaft (17) and drive shaft (18) rotate at the same speed. Therefore, drive pump (8) and idler pump (3) rotate at the same speed.

Pilot pump (11) is directly connected with drive shaft (17) .

Barrel (25) contains nine pistons (24). Piston slippers (23) are connected to pistons (24) by retainers (22). The piston slippers are pressed against plate (21). Plate (21) lies on swashplate (20). Barrel (25) is splined to drive shaft (18). As drive shaft (18) rotates, the barrel, the pistons and the piston slippers rotate around swashplate (20) .

The angle of swashplate (20) determines the length of stroke of piston (24). As the angle of the swashplate increases, the length of stroke of the pistons increases and the output flow of the pump increases. As piston slipper (23) rotates around the swashplate, the piston moves out of barrel (25). The piston draws oil from passage (27) of port plate (26) during this movement. As the piston slipper continues to rotate around the swashplate, the piston moves into the barrel. The piston delivers oil to outlet port (13) during this movement. The oil delivery from ports (4) and (9) flows to the main control valve.

(51)

Pump Control (Main Hydraulic) - Main Pump Regulator

SMCS - 3222; 5070; 5086

Operation

The regulators for the drive pump and the idler pump are identical in construction and operation. The following description is given for the drive pump regulator.

The main pump regulators are controlled in the following manner.

Power Shift System - The pump regulators are controlled by the electronic control system. The

engine and pump controller continually monitors the engine speed and the load on the engine. The engine and pump controller sends an electrical signal to the proportional reducing valve for power shift pressure. The proportional reducing valve assists in controlling the output flow of the pumps by changing the hydraulic signal pressure (power shift pressure) that flows to the pump regulators.

Cross sensing control - The pump regulators are controlled by cross sensing control. In order to

maintain the engine horsepower to the pumps at a constant rate, the pump regulators receive average delivery pressure of the drive pump and the idler pump through the cross sensing control. This is called constant horsepower control.

Negative Flow Control - When the joysticks and/or the travel levers/pedals are in the NEUTRAL

position or when the joysticks and/or the travel levers/pedals are partially moved from the NEUTRAL position, the pump regulators receive negative flow control pressure from the main control valve. The main pumps are controlled by negative flow control pressure at this time.

Reference: For more information concerning the power shift system, refer to Systems Operation,

"Pilot Hydraulic System".

Reference: For more information concerning the negative flow control operation at the main control

valve, refer to Systems Operation, "Negative Flow Control".

Shutdown

(52)

The output characteristics of each pump depends on the following pressures.

z Pump output circuit pressure z Power shift pressure

z Negative flow control pressure

The flow rate of each pump is represented on P-Q characteristic curve (B) from pressure/flow point (A). Each point on the P-Q characteristic curve represents the flow rate and pressure when pump output horsepower is maintained at a constant rate.

Pump Regulator

P-Q characteristic curve

(A) Pressure/flow point (destroke point) (B) P-Q characteristic curve

(53)

Illustration 2 g01111887 Idler pump regulator

(1) Spool (2) Shoulder (3) Piston (4) Passage (5) Plate (6) Feedback lever

(54)

Pump delivery pressure (PD) acts on pilot piston (3) and spool (1) of regulator (16). Power shift pressure (PS) enters regulator (16) through a passage through the main pump housing. The oil then goes through passage (10) to piston (9) .

During constant horsepower flow control, pump delivery pressure (PD) is acting on the right

shoulder of pilot piston (3). Also during constant horsepower flow control, power shift pressure (PS) and cross sensing control pressure (CP) from the idler pump is acting on the left end of piston (3). When the total force of the three pressures is less than the force of spring (7) and spring (8), pilot piston (3) remains stationary. Swashplate (13) maintains the maximum angle for maximum pump flow. When the total force of the three pressures is greater than the force of spring (7) and spring (8), pilot piston (3) is shifted in order to decrease the swashplate angle which will destroke the pump. During negative flow control, negative flow control pressure (PN) from line (17) acts on the left end surface of pilot piston (18). Pilot piston (18) shifts in order to move feedback lever (5), spool (1) and related components. Negative flow control is maximum when all the control levers are in the

NEUTRAL position which requires no pump flow.

Regulator Operation (full stroke position)

(7) Spring

(8) Spring

(10) Passage (power shift pressure) (PS) Power shift pressure

(CF) Cross sensing control pressure (PD) Delivery pressure (drive pump) (11) Chamber (12) Piston (13) Swashplate (14) Chamber (15) Rod (16) Regulator

(17) Negative flow control line (18) Rod

(55)

Drive pump regulator (1) Spool (2) Shoulder (3) Piston (4) Passage (5) Plate (6) Feedback lever (7) Spring (8) Spring (9) Piston

(56)

Main pump delivery pressure (PD) acts on shoulder (2) of pilot piston (5). Power shift pressure (PS) from passage (10) acts on piston (9) and on the left end of pilot piston (3). When the total force of main pump delivery pressure (PD), power shift pressure (PS), and cross sensing control pressure (CF) is less than the total force of spring (7) and spring (8) pilot piston (3) remains stationary. Plate (5), feedback lever (6), and spool (1) remain stationary. Passage (4) remains blocked. Main pump delivery pressure (PD) cannot enter piston chamber (11) while there is main pump delivery pressure (PD) in piston chamber (14). Piston (12) is shifted all the way to the left. Swashplate (13) is held at a maximum angle which allows the pump to maintain maximum output flow. Main pump delivery pressure (PD), power shift pressure (PS), and cross sensing control pressure (CF) flow to the regulator from passages within the main pump housing.

Regulator Operation (minimum stroke position)

(PD) Delivery pressure (drive pump)

(11) Chamber (12) Piston (13) Swashplate (14) Chamber

(57)

When all of the controls are in the NEUTRAL position, no load is present to the drive pump which causes a increase in power shift pressure (PS) and a increase in drive pump delivery pressure (PD) inside the pump. The larger pressures from power shift pressure (PS), delivery pressure (PD), and cross sensing control pressure (CF) combine in order to overcome the forces of spring (7) and spring (8) which shifts piston (3).

Piston (3) shifts rod (15) to the right, rotating lever (6), which rotates lever (5). Lever (5) is

connected to spool (1). When lever (5) is rotated spool (1) shifts to the right. This opens passage (4). Delivery pressure (PD) now flows to chamber (11). Lever (5) is also connected to piston (12). When lever (5) is rotated a force is placed against piston (12). The combined force of delivery pressure (PD) and force from lever (5) causes piston (12) to shift to the right. Piston (12) then rotates swashplate (13) to zero angle. The pump displacement is now minimal.

Regulator Operation (standby position)

Pump regulator (machine at idle condition) (1) Spool (2) Shoulder (3) Piston (4) Passage (5) Plate (6) Feedback lever (7) Spring (8) Spring (9) Piston

(CF) Cross sensing control pressure (PD) Delivery pressure (drive pump) (11) Chamber

(12) Piston (13) Swashplate (14) Chamber (15) Rod

(58)

Illustration 5 g01129993 Drive pump regulator

(1) Spool (2) Shoulder (3) Piston (4) Passage (5) Plate (6) Feedback lever (7) Spring (8) Spring (9) Piston

(59)

The regulator is in the standby mode when all the controls are in the NEUTRAL position and the engine and pump controller raises the power shift pressure to a level that is dependent on the engine speed. Power shift pressure (PS) acts on piston (9). Cross sensing control pressure from the idler pump acts on piston (3) as well as delivery pressure (PD). Negative flow control pressure is at maximum pressure, which acts against piston (18). The engine speed keeps delivery pressure (PD) higher than the negative flow control pressure, power shift pressure (PS), and cross sensing flow pressure (CF). Spring (7) and spring (8) also act with delivery pressure to keep piston (12) from shifting to the right. The swashplate is at a maximum angle. Standby keeps the pump at a maximum angle, although little pressure is needed to destroke the pump.

(PD) Delivery pressure (drive pump) (11) Chamber

(12) Piston (13) Swashplate (14) Chamber

(60)

Main Control Valve

SMCS - 5051

Shutdown

i02482368

Hydraulic schematic

(1) Stick drift reduction valve

(61)

(3) Boom drift reduction valve

(4) Line relief valve (boom cylinder head end) (5) Return port

(6) Main control valve (7) Stick regeneration valve (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

(62)

(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) Pressure port (left pump)

(38) Negative flow control line (left pump) (39) Pressure port (right pump)

(40) Negative flow control line (right pump) (41) Left pump

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

(63)

Main control valve ports

(AR1) Right travel control 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)

(64)

(BR5) Stick II control valve (STICK OUT) (AL1) Left travel control (REVERSE TRAVEL) (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 control valve (REVERSE TRAVEL) (aR2) Pilot port at attachment control valve

(aR3) Pilot port at bucket control valve (BUCKET CLOSE) (aR4) Pilot port at boom I control valve (BOOM LOWER) (aR5) Pilot port at stick II control valve (STICK IN)

(aL1) Pilot port at left travel control valve (REVERSE TRAVEL) (aL2) Pilot port at swing control valve (SWING LEFT)

(aL3) Pilot port at stick I control 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 pump) (HR) Negative flow signal pressure port (right pump)

(65)

Introduction

(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

(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

(66)

Main control valve (6) is located in the hydraulic system between the main pumps and actuators

(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

Main control valve (bottom view) (3) Boom drift reduction valve

(4) Line relief valve (boom cylinder head end)

Bottom view of main control valve (1) Stick drift reduction valve