1、SERV7107-05Vol. 5, No. 1May 2007TECHNICAL PRESENTATION300D SERIES HYDRAULICEXCAVATORS - TIER III ENGINESMAIN HYDRAULIC PUMPS AND CONTROLS(INCLUDES 320D, 321D, 323D, 324D, 325D, 328D AND 330D)New Product Introduction(NPI)GLOBAL SERVICE LEARNING300D SERIES HYDRAULICEXCAVATORS - TIER III ENGINESMAIN HY
2、DRAULIC PUMPS AND CONTROLSAUDIENCELevel II - Service personnel who understand the principles of machine systems operation,diagnostic equipment, and procedures for testing and adjusting.CONTENTThis presentation provides an introduction and describes the components and systems operationof the 300D Ser
3、ies main hydraulic pumps and controls. Additional presentations will cover themachine walkaround, engines, pilot system, main control valve group, implements swingsystem, travel system, and tool control systems in more detail. This presentation may be usedfor self-paced and self-directed training. O
4、BJECTIVESAfter learning the information in this presentation, the technician will be able to:1. identify the components and explain the operation of the 300D Series hydraulicexcavators main hydraulic pumps and controls, and2. diagnose problems in the main hydraulic pumps and controls.REFERENCES320D
5、Hydraulic Excavator Specalog AEHQ5856324D Hydraulic Excavator Specalog AEHQ5663325D Hydraulic Excavator Specalog AEHQ5665328D Hydraulic Excavator Specalog AEHQ5706330D Hydraulic Excavator Specalog AEHQ5667NPI “325D Hydraulic Excavator - Introduction“ SERV7105-12NPI “330D Hydraulic Excavator - Introd
6、uction“ SERV7106-02Machine Monitoring System - Systems Operation RENR8068Self-study “300D Series Hydraulic Excavators, 345C Hydraulic Excavator, and 365C & 385C Large Hydraulic Excavators SERV7032iTIM “ 300C Series Hydraulic Excavators-Electronic Control Systems“ SERV2693iTIM “325C Hydraulic Excavat
7、ors-Hydraulic Systems“ SERV2701325D Hydraulic Schematic KENR6157Estimated Time: 1 hourIllustrations: 22Form: SERV7107-05Date: May 2007: Vol. 5, No. 1 2007 Caterpillar Inc.TABLE OF CONTENTSINTRODUCTION 5320D - 328D Main Hydraulic Pump Group.11330D Main Hydraulic Pump Group .21CONCLUSION.35SERV7107-05
8、 - 3 - Text ReferenceVol. 5, No. 1PREREQUISITES“Fundamentals of Mobile Hydraulics Self Study Course“ TEMV3002“Fundamentals of Power Train Self Study Course“ TEMV3003“Fundamentals of Electrical Systems Self Study Course“ TEMV3004“Fundamentals of Engines Self Study Course“ TEMV3001NOTESSERV7107-05 - 4
9、 - Text ReferenceVol. 5, No. 1X53X74X69X63X6BX20X43X79X6CX69X6EX64X65X72X42X75X63X6BX65X74X20X43X79X6CX69X6EX64X65X72 X42X6FX6FX6DX20X43X79X6CX69X6EX64X65X72X73X53X77X69X6EX67X20X4DX6FX74X6FX72 X54X72X61X76X65X6CX20X4DX6FX74X6FX72X73X50X69X6CX6FX74X20X43X6FX6EX74X72X6FX6CX20X56X61X6CX76X65X73X50X72X
10、69X6FX72X69X74X79X20X56X61X6CX76X65X73X4DX61X69X6EX20X48X79X64X72X61X75X6CX69X63X20X50X75X6DX70X73X4DX50X69X6CX6FX74X20X50X75X6DX70X46X61X6EX20X4DX6FX74X6FX72X50X69X6CX6FX74X20X4DX61X6EX69X66X6FX6CX64X4DX61X69X6EX20X43X6FX6EX74X72X6FX6CX20X56X61X6CX76X65X20X47X72X6FX75X70X46X61X6EX20X50X75X6DX70X54X
11、61X6EX6BX54X68X65X20X46X61X6EX20X4DX6FX74X6FX72X20X61X6EX64X20X50X75X6DX70X20X61X72X65X20X6FX6EX6CX79X20X75X73X65X64X20X6FX6EX20X74X68X65X20X33X33X30X44X4DX41X49X4EX20X48X59X44X52X41X55X4CX49X43X20X50X55X4DX50X53X20X41X4EX44X20X43X4FX4EX54X52X4FX4CX53INTRODUCTIONThis section of the presentation will
12、 cover the main hydraulic pumps and pump controls for the300D Hydraulic Excavators. The main pump group consists of a variable displacement piston drive pump and an idler pump.The drive pump and the idler pump are contained in an integral housing. The drive pump andthe idler pump are identical in co
13、nstruction and operation.The pumps are sometimes referred to as S.B.S. (side by side) pumpsThe main difference between all of the pumps is the maximum pump flow for each model.Both the drive pump and the idler pump have individual pump control valves to control thepump flow.The 320D through the 328D
14、 use the same type of pump control valve. The 330D pump controlvalve is the same as the pump control used on the 345C pump.1SERV7107-05 - 5 - Text ReferenceVol. 5, No. 12Power shift pressure is controlled by the Machine ECM, and assists in pump regulation. Powershift pressure is one of three pressur
15、es to control the pump.The pilot pump supplies the power shift PRV solenoid with pilot oil. The Machine ECMmonitors the selected engine speed (from the engine speed dial), the actual engine speed (fromthe engine speed sensor and Engine ECM), and the pump output pressures (from the outputpressure sen
16、sors). The power shift PRV solenoid regulates the pressure of the power shift oildepending upon the signal from the Machine ECM.When the engine speed dial is in position 10, the Machine ECM varies the power shift pressurein relation to the actual speed of the engine.The power shift pressure is set t
17、o specific fixed values dependent upon the position of theengine speed dial. The fixed power shift pressures assist cross sensing pressure with constanthorsepower control. SERV7107-05 - 6 - Text ReferenceVol. 5, No. 1X45X6EX67X69X6EX65X20X53X70X65X65X64X20X53X65X6EX73X6FX72X45X6EX67X69X6EX65X20X45X4
18、3X4DX4DX61X63X68X69X6EX65X20X45X43X4DX20X50X69X6CX6FX74X20X50X75X6DX70X49X64X6CX65X72X20X28X4CX65X66X74X29X20X50X75X6DX70X44X72X69X76X65X20X28X52X69X67X68X74X29X20X50X75X6DX70X50X6FX77X65X72X20X53X68X69X66X74X20X50X52X56X20X53X6FX6CX65X6EX6FX69X64X20X4DX6FX6EX69X74X6FX72X45X6EX67X69X6EX65X20X53X70X6
19、5X65X64X20X44X69X61X6CX50X75X6DX70X20X43X6FX6EX74X72X6FX6CX20X56X61X6CX76X65X50X4FX57X45X52X20X53X48X49X46X54X20X50X52X45X53X53X55X52X45X20X53X59X53X54X45X4DWhen the engine speed dial is on position 10 and a hydraulic load is placed on the engine, thiscondition causes the engine speed to decrease be
20、low the engines target rpm.When this decrease occurs, the Machine ECM signals the power shift solenoid to sendincreased power shift pressure to the pump control valves. The increased power shift signalcauses the pumps to destroke, and reduce the horsepower demand placed on the engine. With adecrease
21、d load from the hydraulic pumps the engine speed increases. This function is referredto as engine underspeed control.Engine underspeed control prevents the engine from going into a “stall“ condition where enginehorsepower cannot meet the demands of the hydraulic pumps. The power shift signal to thep
22、ump control valves enables the machine to maintain a desired or target engine speed formaximum productivity.Power shift pressure has the following effect on the main hydraulic pumps:- As power shift pressure decreases, pump output increases.- As power shift pressure increases, pump output decreases.
23、Power shift pressure ensures that the pumps can use all of the available engine horsepower atall times without exceeding the output of the engine.NOTE: The target rpm is the full load speed for a specific engine no load rpm. Enginetarget rpm is determined by the opening of one of the implement, swin
24、g, and/or travelpressure switches at the end of an operation. The Machine ECM then waits 2.5 secondsand records the engine speed. This specific rpm is the “new“ no load rpm. The Machine ECM then controls the power shift pressure to regulate pump flow tomaintain the full load (target) rpm for the rec
25、orded no load rpm.Target rpm can change each time the pressure switches open for more than 2.5 seconds.SERV7107-05 - 7 - Text ReferenceVol. 5, No. 13The solenoid operated proportional reducing valve for the power shift pressure is located on theright/drive pump control valve. The proportional reduci
26、ng valve receives supply oil from thepilot pump. The solenoid receives a pulse width modulated signal (PWM signal) from the Machine ECM.The PWM signal sent from the Machine ECM causes the proportional reducing valve toregulate the pilot pressure to the pump control valves to a reduced pressure. This
27、 reduced pressure is called power shift pressure (PS). The output flow of the right/drive pump and the left/idler pump is controlled in accordance withthe power shift pressure. The power shift pressure is used to control the maximum hydraulicpump output in relation to the engine rpm.A decrease in en
28、gine speed causes an increase in power shift pressure and a decrease in pumpflow. SERV7107-05 - 8 - Text ReferenceVol. 5, No. 1X53X6FX6CX65X6EX6FX69X64X53X70X72X69X6EX67X50X52X4FX50X4FX52X54X49X4FX4EX41X4CX20X52X45X44X55X43X49X4EX47X20X56X41X4CX56X45X20X50X57X4DX20X53X49X47X4EX41X4CX20X49X4EX43X52X4
29、5X41X53X45X50X69X6CX6FX74X20X50X72X65X73X73X75X72X65X50X6FX77X65X72X20X53X68X69X66X74X20X50X72X65X73X73X75X72X65X54X61X6EX6BX50X6CX75X6EX67X65X72When the speed dial is at dial position 10, if the Machine ECM senses a decrease in enginespeed below target rpm, the Machine ECM increases the PWM signal
30、sent to the solenoid. The magnetic force of the solenoid increases. As the magnetic force of the solenoid becomesgreater than the force of the spring, the spool moves down against the force of the spring. The downward movement of the spool blocks the flow of oil to the tank.More power shift pressure
31、 oil is now directed to the pump control valve.The increased power shift pressure acts on the drive pump control valve and the idler pumpcontrol valve. If both pumps are upstroked, then both pumps will destroke as a result of the increase in powershift pressure. If only one pump is upstroked, only t
32、he upstroked pump will destroke.SERV7107-05 - 9 - Text ReferenceVol. 5, No. 14If engine speed is above the target rpm, the Machine ECM decreases the power shift pressure toincrease the pump flow. When the Machine ECM senses an increase in engine speed above the target speed the MachineECM decreases
33、the PWM signal sent to the solenoid. As the magnetic force of the solenoid becomes less than the force of the spring, the spoolmoves up.The upward movement of the spool restricts the pilot oil flow to the power shift passage andopens the power shift passage to the drain. The power shift pressure is
34、reduced.The reduced power shift pressure acts on the drive pump control valve and the idler pumpcontrol valve. Depending on which circuits are activated, the drive pump and/or the idler pump will upstrokeas a result of an decrease in power shift pressure.SERV7107-05 - 10 - Text ReferenceVol. 5, No.
35、1X53X6FX6CX65X6EX6FX69X64X53X70X72X69X6EX67X50X52X4FX50X4FX52X54X49X4FX4EX41X4CX20X52X45X44X55X43X49X4EX47X20X56X41X4CX56X45X20X50X57X4DX20X53X49X47X4EX41X4CX20X44X45X43X52X45X41X53X45X50X69X6CX6FX74X20X50X72X65X73X73X75X72X65X50X6FX77X65X72X20X53X68X69X66X74X20X50X72X65X73X73X75X72X65X54X61X6EX6BX5
36、0X6CX75X6EX67X65X725320D - 328D Main Hydraulic Pump GroupThis illustration shows the main hydraulic pumps groups. The drive pump (right pump) (1) isdriven by the engine and the idler pump (left pump) (2) is driven by the drive pump. The pilotpump (3) is mounted on the drive pump. The medium pressure
37、 pump (4) is driven by the idlerpump.The drive pump supplies oil to the right half of the main control valve group and the followingvalves: - stick 2 control valve- boom 1 control valve- bucket control valve- attachment control valve- right travel control valveSERV7107-05 - 11 - Text ReferenceVol. 5
38、, No. 1513642The idler pump supplies oil to the left half of the main control valve group and the followingvalves: - left travel control valve- swing control valve- stick 1 control valve- boom 2 control valve- auxiliary valve for tool control (if equipped)The output of the variable-displacement pist
39、on pumps is controlled by the pump control valves(5 and 6) mounted on the main hydraulic pumps. SERV7107-05 - 12 - Text ReferenceVol. 5, No. 16This illustration shows the pump control valve for the drive pump. Except for the power shiftsolenoid, the components for the idler pump are identical. The p
40、ower shift PRV solenoid (1) provides a common power shift pressure for both pumps.The power shift PRV solenoid is controlled by the Machine ECM. The pump output pressure sensors (2) signals the Machine ECM of each pumps outputpressure. The Machine ECM uses the pump output pressure, actual engine spe
41、ed, and desiredengine speed to determine the power shift pressure. The pressure sensors also signal theMachine ECM to cancel the AEC settings if the pump pressure increases above approximately7370 kPa (1100 psi) and the engine rpm is still at an AEC setting.The horsepower adjusting screws (3) adjust
42、 the hydraulic horsepower output of each pump.The maximum angle screw (4) limits the maximum flow of each pump.The pressure tap (5) above the power shift PRV solenoid can be used to check the PRV signalpressure. The pressure tap (6) just above the pressure sensor can be used to check the drivepump s
43、upply pressure. Another the pressure tap (not shown) can be used to check the idlerpump supply pressure. Cat ET can also be used to check these two pressures.SERV7107-05 - 13 - Text ReferenceVol. 5, No. 11234567This illustration shows the pumps in STANDBY condition. The pump control valves will upst
44、roke, destroke, or maintain the displacement of the pumpdepending on the conditions the pump control valve senses. The pump control valve controlsoil pressure (stroking pressure) to the right side of the actuator, which controls the angle of thepump swashplate. Each pump has a pump control valve whi
45、ch senses the three following control signals:- a pump specific Negative Flow Control (NFC) signal from the main control valve group- a common power shift signal pressure generated by the power shift PRV- a common cross sensing signal pressure from the output of the two main pumpsNFC: NFC pressure i
46、s the most significant controlling signal in a negative flow controlledhydraulic system. Each pump control valve receives a specific NFC signal that is based uponthe hydraulic demand for that specific pump.SERV7107-05 - 14 - Text ReferenceVol. 5, No. 1X55X55X4DX47X65X6EX65X72X61X74X6FX72X20X50X75X6D
47、X70X41X63X74X75X61X74X6FX72X49X64X6CX65X72X20X50X75X6DX70X44X72X69X76X65X20X50X75X6DX70X50X69X6CX6FX74X20X50X75X6DX70X4DX65X64X20X50X72X65X73X73X20X50X75X6DX70X4DX61X69X6EX20X43X6FX6EX74X72X6FX6CX20X56X61X6CX76X65X20X47X72X6FX75X70X20X28X52X69X67X68X74X20X53X69X64X65X29X50X69X6CX6FX74X20X46X69X6CX74
48、X65X72X20X61X6EX64X20X4DX61X6EX69X66X6FX6CX64X50X69X6CX6FX74X20X50X75X6DX70X4DX65X64X69X75X6DX20X50X72X65X73X73X75X72X65X20X43X69X72X63X75X69X74X4DX61X69X6EX20X43X6FX6EX74X72X6FX6CX20X56X61X6CX76X65X20X47X72X6FX75X70X20X28X4CX65X66X74X20X53X69X64X65X29X4CX65X66X74X20X4EX46X43X20X43X6FX6EX74X72X6FX6C
49、X20X4FX72X69X66X69X63X65X52X69X67X68X74X20X4EX46X43X20X43X6FX6EX74X72X6FX6CX20X4FX72X69X66X69X63X65X4FX75X74X70X75X74X20X50X72X65X73X73X75X72X65X20X53X65X6EX73X6FX72X50X75X6DX70X20X43X6FX6EX74X72X6FX6CX20X56X61X6CX76X65X43X61X73X65X20X44X72X61X69X6EX4DX41X49X4EX20X50X55X4DX50X20X47X52X4FX55X50X20X53X54X41X4EX44X42X59X43X72X6FX73X73X20X53X65X6EX73X69X6EX67X20X4FX72X69X66X69X63X65X4DX31X4DX32X50X53X32X50X6FX77X65X72X20X53X68X69X66X74X20X50X52X56Flow from the drive pump supplies the right half of the main control valve group, and has acorresponding NFC signal for the drive pump. Flow from th
