Sơ đồ thủy lực máy đào CAT 320 - P5

Sơ đồ thủy lực máy đào CAT 320

Systems Operation

320C U Excavator Hydraulic System

Pilot Hydraulic System

SMCS - 5050

Shutdown SIS

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Product: EXCAVATOR

Model: 320C EXCAVATOR MAC

Configuration: 320C U & 320C LU Excavators

MAC00001-UP (MACHINE) POWERED BY 3066 Engine

i01429693

(1) Swing parking brake

(2) Displacement change valve (left travel motor)

(3) Displacement change valve (right travel motor)

(4) Line (pilot oil from swing parking 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 stick and swing)

(23) Pilot line (pilot oil to pilot control valve for 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)

(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 parking brake solenoid valve

(46) Valve (hydraulic activation)

(47) Pressure reducing valve for swing priority

(48) Pressure reducing valve for boom priority

(49) Left pump

(50) Passage (power shift pressure)

(51) Pilot manifold

(52) Travel speed solenoid valve

(53) Passage

(54) Hydraulic activation solenoid valve

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

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

(55) Passage

(56) Passage

(57) Passage

(58) Right pump

(59) Pilot pump

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

(61) Pilot filter

(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 pilot manifold

(45) Swing parking brake solenoid valve

(46) Valve (hydraulic activation)

(52) Travel speed solenoid valve

(54) Hydraulic activation solenoid valve

z Power shift pressure system

z Pilot control valve circuit

z Pressure switch circuits

z Straight travel valve circuit

z Swing parking brake

z Boom priority

z Swing priority

z Automatic travel speed change

Power Shift Pressure System

(49) Left pump

(58) Right pump

(63) Proportional reducing valve (PS pressure)

(59) Pilot pump

(68) Engine and pump controller

(69) Monitor

(70) Engine speed dial

(71) Right pump pressure sensor

(72) Left pump pressure sensor

(73) Feedback sensor

During machine operation, engine and pump controller (68) receives input signals from the following components:

z Engine speed dial (70)

z Engine speed sensor (75) that is located on the flywheel housing

z Right pump pressure sensor (71)

z Left pump pressure sensor (72)

z Monitor in the cab (69)

z Feedback sensor (73) at governor actuator (74)

The engine and pump controller (68) continually monitors all of the input signals The input signals are processed by the engine and pump controller and an output signal is sent to proportional reducing valve (63) at the right pump regulator The proportional reducing valve assists

in controlling the output flow of right pump (58) and left pump (49)

The oil delivery from pilot pump (59) flows through the pilot filter to proportional reducing valve (63) at the right pump regulator The electrical signal that is sent from engine and pump controller (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 right pump regulator and through the left pump regulator The output flow of right pump (58) and left 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 engine and pump controller to the proportional reducing valve will change when the engine and pump controller detects a change in any of the input signals The power shift pressure that is sent to the regulators at the right pump and the left 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 right pump and the left 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 right pump and the left pump The maximum allowable hydraulic power output is increased

Note: For more information concerning the operation of the engine and pump controller, refer to Systems Operation/Testing and Adjusting,

"Engine and Pump 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 hydraulic activation control lever is shifted to the UNLOCKED position, the engine and pump controller energizes the hydraulic activation solenoid 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

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 right 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 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 engine and pump controller 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 engine and pump controller activates the AEC system in order to

(74) Governor actuator

(75) Engine speed sensor (flywheel housing)

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 engine and pump controller The engine and pump controller 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 Parking Brake

When the hydraulic activation control lever is placed in the UNLOCKED position, pilot oil in passage (57) flows through valve (46) and passage (53) to swing parking 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 engine and pump controller An electrical signal from the engine and pump controller energizes the swing parking brake solenoid valve (45) Pilot oil in line (4) flows to swing parking brake (1) This oil releases the swing parking brakes For more information concerning the operation of the swing parking brake, refer to Systems Operation, "Pilot Valve (Swing Parking 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

During a swing operation, pilot oil flows from pilot control valve (25) to the pressure reducing valve 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 left 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"

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Mon Mar 18 14:47:13 UTC+0700 2002