05液压系统hydraulic system.pdf

液压系统Hydraulic system

1.液压基础知识

Hydraulic basic knowledge2.液压元件介绍

The introduction of hydraulic components3.挖掘机液压系统

Hydraulic system of excavator4.液压管路介绍

The introduction of hydraulic pipe line5. 压力测试与调整

Pressure test and adjust6. 故障分析与处理

Troubleshooting

目录Table of contents

1.1 帕斯卡原理Pascal’s theorem

1. 处于密闭容器内的液体对施加于它表面的压力向各个方向等值传递。Pressure on a confined liquid will exert the same force in all directions equally .

2.速度的传递按“容积变化相等”的原则The speed of the load, as it moves, is in direct proportion to the area of it’s cylinder verses the area of the cylinder F.

3.液体的压力由外载荷建立。认为泵一出油就有压力是错误的。Fluid pressure is created by external load. No load, no pressure.

4.能量守恒Conservation of energy

Load

Full of oil

Small areaLarge area

F＝p×A v＝q÷AP＝v×F

F

F--force p--pressureA--area q--flowP--power v--speed

1.2 液压系统常用线型和符号Lines and symbols commonly used in hydraulic systems

粗实线表示工作管路 Thick solid lines represent work lines

双点划线表示组合元件 Double dotted lines represent combined elements有小圆点的相交线表示连接管路 Intersect lines with small dots represent connected lines.有小圆弧的相交线表示不相交连接管路 Intersecting lines with small circular offset, represent lines or circuits that do not meet

线型 Lines:

虚线表示控制管路 Broken solid lines represent pilot or drain lines

符号 Symbols：P——泵压力油 Pressure oil of pumpA、B——油缸或马达的工作油口

The work oil port of cylinder or motorO、T、Dr——油箱 Reservoir

1.3 液压系统的基本构成Basic composition of the hydraulic system

液压系统由4部分组成：Hydraulic system consist of 4 parts:

液压泵：将机械能转换为液体压力能。Hydraulic pump: Converts the mechanical energy to hydraulic energy.

执行元件：将液体压力能转换为机械能。例如油缸、油马达等。Implement components: Convert the hydraulic energy to mechanical energy. For example cylinder, motor and so on.

1.3 液压系统的基本构成Basic composition of the hydraulic system

控制元件：各种阀。大致有压力控制阀、流量控制阀、方向控制阀等。Control components: Valves. Generally, there are pressure control valves, flow control valves, directional control valve.

辅助元件：油箱、过滤器、管路、接头、密封、冷却器、蓄能器等等。Auxiliary components: Hydraulic tank, filters, piping, joints, seals, coolers, accumulators and so on.

1.4 液压元件符号Symbol of hydraulic components

单向、定排量One-way, fixed displacement

液压泵 Hydraulic pump:

双向、定排量Two-way, fixed displacement

单向、变排量One-way, variable displacement

液压阀 Hydraulic valves :

单向阀One-way valve

梭阀Shuttle Valve

节流阀Flow Control Valve

可变节流阀Variable Flow Control Valve

溢流阀Relief valve

压力减压阀Pressure reducing valve

电磁阀Solenoid valve


截止阀Shut-off valve

液压马达 Hydraulic motor:

单向、定排量One-way, fixed displacement

双向、定排量Two-way, fixed displacement

双向、变排量Two-way, variable displacement


双作用液压缸Double-acting hydraulic cylinder

单作用液压缸Single-acting hydraulic cylinder

A B A B

液压缸 Hydraulic cylinder :



辅助元件 Auxiliary components:

液压油箱HydraulicReservoir

散热器Cooler

蓄能器Accumulator

过滤器Filter

1.5 推荐用液压油Recommended Hydraulic oil

如果需要额外的信息，请联系柳工总部Please contact LiuGong Headquarters for additional information. 禁止使用马达润滑油Use of Motor oil is prohibited.







Troubleshooting


主要液压元件Main hydraulic components

主泵Main pump

行走先导阀Travel pilot valve

主控阀Main control valve

回转马达及减速机Swing Motor&Reducer

行走马达及减速机Travel Motor&Reducer

手先导阀Pilot valve

先导阀块Pilot valve block

2.1 主泵 Main pump2.2 主控阀 Main control valve2.3 回转马达及减速机 Swing Motor&Reducer2.4 行走马达及减速机 Travel Motor&Reducer2.5 手先导阀 Pilot valve2.6 行走先导阀 Travel pilot valve2.7 先导阀块 Pilot valve block

2. 液压元件介绍The introduction of hydraulic components

2.1 主泵 (描述)Main pump (description)

该泵由主泵和先导泵构成。主泵是可变排量轴向柱塞泵，他提供高压油给

液压系统。先导泵是定排量齿轮泵，它给控制系统提供先导油。主泵由发动机通过联轴器驱动，先导泵与主泵的轴直接连接，转速和主泵一致。

This pump is composed of main pump and pilot pump. The main pump is a variable displacement axial plunger pump. It provides high pressure oil for the hydraulic system of excavator. The pilot pump is a fixed displacement gear pump. It supplies oil for the control system. The main pump is driven by the engine through a coupler. The pilot gear pump is connected directly by the drive shaft of the main pump at the same rotate speed.

2.1 主泵 (主要参数)Main pump (main parameters)

条目 Item 单位 unit 920D/922D 923D/925D

型式 TypeDuplex Variable Axial Piston Pump

Duplex Variable Axial Piston Pump

排量Displacement cc 108 115

流量 Flow L/min 2×215 2×230

主泵Main pump

先导泵Pilot pump

额定压力

Rated pressure MPa 34.3 34.3

流量 Flow L/min 20 20

型式 Type Gear pump Gear pump排量

Displacement cc 10 10

额定压力

Rated pressure MPa 3.9 3.9

2.1 主泵(外形)Main pump (shape)

左泵Left pump

右泵Right pump

先导泵Pilot pump

主泵测压口The port of main pressure test

左泵调节器Regulator for right pump

右泵调节器Regulator for right pump

电比例减压阀Solenoid ProportionalReducing Valve

最大流量调整螺钉The adjust bolt of max. flow

先导泵测压口The port of pilot pressure test

先导压力调整螺钉Pilot pressure adjust bolt

最小流量调整螺钉The adjust bolt of min. flow

泄油口Port for Leakage

泵出油口Oil outlet

最小流量调整螺钉The adjust bolt of min. flow

适用机型 Models：920D (Ⅱ)922D (Ⅱ)923D (Ⅱ)925D (Ⅱ)

2.1 主泵(液压回路图)Main pump (Hydraulic schematic )

P1泵调节器Regulator for P1 pump

P2泵调节器Regulator for P2 pump

P1 pump

P2 pump

Pilot pump

电磁比例减压阀Solenoid ProportionalReducing Valve

适用机型 Models：920D (Ⅱ)922D (Ⅱ)923D (Ⅱ)925D (Ⅱ)、 925D(Ⅲ)

2.2 主控阀(描述)Main control valve (description)

主控阀位于主泵和执行元件（油缸和马达）之间，它控制执行元件的油的方向和流量。控制阀为液压先导控制、开式负流量控制阀，由九个阀芯组成、并联的整体式多路换向阀。包含用于控制动臂、斗杆、铲斗、回转、行走、附属装置的阀芯。控制阀具有动臂上升合流、斗杆合流、斗杆再生、回转优先、动臂、斗杆锁定、直线行走等功能。

The main control valve is located between the main pump and actuators(all of the cylinders and motors).It controls the oil direction, pressure, and flow rate for all of the actuators. Main control valve is pilot control, open negative flow control, and paralleling monolithic multi-ported directional valve composed of nine spools. It includes spools for the boom，arm，bucket，swing，travel and auxiliary devices. Main control valve has the auxiliary functions for boom raise confluence，arm confluence，arm regeneration，swing priority，boom anti-drift，arm anti-drift and straight travel.

2.2 主控阀(主要参数)Main control valve (main parameters)

条目 Item 单位 unit 920D/922D 923D/925D主溢流阀压力(标准)Main relief pressure, (standard)

Mpa 31.8 32.2

主溢流阀压力(增压) Main relief pressure, (boost)

Mpa 33.3 34.6

回转压力Implement circuits Mpa 25.5 25.5

2.2 主控阀(外形)Main control valve (Shape)

左行走阀芯Left travel spool

主溢流阀Main relief valve

备用阀芯Option spool右行走阀芯

Right travel spool

备用油口溢流阀Port relief valve for option spool

动臂锁定阀Lock valve for boom

动臂油口溢流阀Port relief valve for boom spool

铲斗油口溢流阀Port relief valve for bucket spool

动臂1阀芯1st boom spool

铲斗阀芯Bucket spool

回转阀芯Swing spool

动臂2阀芯2nd boom spool

斗杆1阀芯1st arm spool

斗杆锁定阀Lock valve for boom

斗杆油口溢流阀Port relief valve for arm spool

斗杆2阀芯2nd arm spool

直线行走阀Straight travel valve

适用机型 Models：

920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

斗杆1提升阀/LCa1

动臂合流单向阀/CCb

CSpCSp 主溢流阀单向阀/CMR1&CMR2

负反馈油口FR

负反馈油口FL

C1

C2

CP2

备用提升阀/LCo

动臂1提升阀/LCb1

铲斗提升阀/LCk

斗杆2提升阀/LCa2

HV HV


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

2.2 主控阀(外形)Main control valve (Shape)


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

2.2 主控阀(液压回路图)Main control valve (Hydraulic schematic )

2.3 回转马达及减速机(描述)Swing motor & reduction gear (description)

回转马达及减速机由液压马达和减速机组成。它带动挖掘机的上部机构回转。

The swing motor&reducer consists of a hydraulic motor and a reduction gear.It rotates the upper structure of excavator.

920D/922D 923D/925D

2.3 回转马达及减速机(外形)Swing motor & reduction gear (shape)

防反转阀Anti-reversion valve

测压口Port for pressure test

主压力口Port for main pressure

回转制动延时阀Time-delay valve for braking

回转减速机Swing reduction gear

油标尺Oil dipstick

润滑油加注口Port for lubricating oil


适用机型 Models：920D(Ⅱ)922D(Ⅱ)922D(Ⅲ)

2.3 回转马达及减速机(外形)Swing motor & reduction gear (shape)

适用机型 Models：923D(Ⅱ)925D(Ⅱ)925D(Ⅲ)

防反转阀Anti-reversion valve


主压力口Port for main pressure

回转减速机Swing reduction gear




2.3 回转马达及减速机(液压回路图)Swing motor & reduction gear (hydraulic schematic)


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

2.4 行走马达及减速机(描述)Travel motor & reduction gear (description)

行走马达及减速机由液压马达和减速机组成。它带动挖掘机的上部机构回转。它用来控制机器向前、向后、左转、右转运动。行走速度由行走速度控制开关控制。它有两档速度：低速和高速。它不能从高速档自动调到低速档。

The Travel motor & reducer consists of a hydraulic motor and a reduction gear. It is used to control the forward, backward, left turn and right turn operation of the machine.The travel speed can be controled by travel speed control switch.There are two speed positons:Low Speed and High Speed. It does not automatically downshift.

2.4 行走马达及减速机(外形)Travel motor & reduction gear (Shape)

主压力油口Port for main pressure


减速机Travel reduction gear


先导油口/控制行走变速Pilot Port/control travel speed


平衡阀Balance valve

安全阀Relief valve


注油口Refill oil

油位线Oil level mark

放油口Oil drain plug


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

2.4 行走马达及减速机(液压回路图)Travel motor & reduction gear (hydraulic schematic )


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

平衡阀Balance valve


2.5 手先导阀(描述)Pilot valve (description)

手先导阀用于控制执行元件的速度和操作。一个位于驾驶室内座椅左侧，一个位于右侧。在标准模式下，左侧先导阀控制回转、斗杆和喇叭，右侧先导阀控制动臂、铲斗和增压。

The pilot control valve is used to control implements speed andoperation. One is installed on the left side of operator seat in the cab, and another is installed on the right side. The left one controls swing, arm and horn. The right one controls boom and bucket and power boost in standard mode.

2.5 手先导阀(液压回路图)Pilot valve (Hydraulic schematic )

2.6 行走先导阀(描述)Travel pilot valve (Description)

行走先导阀提供先导油至主控阀上的行走阀芯，控制整机前进、后退、左转、右转。它也能控制行走系统平稳的运行。

The travel pilot valve supplies pilot oil for the travel spools of the main control valve to control the forward, backward, left turn and right turn operation of the machine. It also has hydraulic dampeners to smooth operation of the travel system.

2.6 行走先导阀(液压回路图)Travel pilot valve (Hydraulic schematic )

2.7 先导阀块(描述)Pilot valve block (description)

先导油流过先导阀块去遥控先导控制阀。先导阀块上有三个电磁阀，分别控制液压先导锁定、二速行走、主溢流阀增压。

Pilot oil goes through the pilot valve block to remote pilot control valve. There are three solenoid valves which control pilot lock, two speed travel. and power boost of main relief valve.

增压 Power boost

液压先导切断Pilot lock

二速行走 Two speed travel


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

2.7 先导阀块(液压回路图)Pilot valve block (Hydraulic schematic )

液压先导锁定二速行走增压

Pilot Lock Two Speed Travel Power Boost







Troubleshooting


§ 3.1 液压系统参数 Hydraulic system parameters § 3.2 液压系统传动简图 Drive diagram of hydraulic system§ 3.3 液压系统回路图 Hydraulic system schematic

3.3.1 负流量控制系统 Negative flow control system 3.3.2 动臂上升 Boom raise 3.3.3 动臂下降 Boom lower 3.3.4 斗杆伸 Arm out 3.3.5 斗杆收 (带再生功能) Arm In (with regeneration)3.3.6 斗杆收 (不带再生功能) Arm In (without regeneration) 3.3.7 铲斗伸 Bucket in 3.3.8 铲斗收 Bucket out3.3.9 左回转 Swing left3.3.10 右回转 Swing right3.3.11 前进(高速) Forward travel (high speed) 3.3.12 后退( 低速) Backward travel (low speed) 3.3.13 直线行走 Straight travel

3.挖掘机液压系统Hydraulic system of excavator

§ 3.1 液压系统参数Hydraulic system parameters

条目 Item 单位 Unit 920D/922D 923D/925D

1 主泵型式Main pump type

Double Variable Axial Piston Pump

Double Variable Axial Piston Pump

2 主泵排量Main pump displacement cc 108 115

3 主泵总流量Main pump total flow L/min 2×215 2×230

4 主溢流阀压力Relief pressure, main MPa 31.8 32.2

5 增压溢流阀压力Relief pressure, boost MPa 33.3 34.6

6 回转回路压力Swing Circuit pressure MPa 25.5 25.5

7 行走回路压力Travel circuit Pressure MPa 31.8 31.8

8 动臂大/小腔溢流阀压力Boom Head/Rod Relief Pressure MPa 36.3/36.3 36.6/36.6

9 斗杆大/小腔溢流阀压力Arm Head/Rod Relief Pressure MPa 37.2/37.2 36.6/37.2

10 铲斗大/小腔溢流阀压力Bucket Head/Rod Relief Pressure MPa 35.3/36.3 36.6/37.2

11 备用溢流压力Option Relief Pressure Mpa 19.6 19.6

12 先导泵型式 Pilot pump type 齿轮泵 Gear pump 齿轮泵 Gear pump

13 先导泵排量Pilot pumpdisplacement cc 10 10

14 先导泵流量Pilot pump flow L/min 20 20

15 先导压力Pilot pressure MPa 3.9 3.9

16

动臂油缸(缸径×杆径×行程 –最小安装距 ) boom cylinder (Bore×rod×Stroke -Min. Installation Dimension )

mm 120×85×1187-1794 φ125×φ90×1350×1950

17

斗杆油缸(缸径×杆径×行程 –最小安装距 ) arm cylinder (Bore×rod×Stroke -Min. Installation Dimension )

mm 135×95×1450-2063 φ140×φ105×1610×2235

18

铲斗油缸(缸径×杆径×行程 –最小安装距 ) bucket cylinder (Bore×rod×Stroke -Min. Installation Dimension )

mm 120×85×1058-1593 φ130×φ90×1075×1665

19 液压油(油箱/系统)hydraulic oil (tank/system) L 230/330 230/330

20 回转马达齿轮油Swing motor gear oil L 3.4 4.4

21 行走马达齿轮油Drive motor gear oil L 5.5*2 5.5*2

§ 3.1 液压系统参数Hydraulic system parameters

§ 3.2 液压系统传动简图Drive diagram of hydraulic system

驱动控制油操纵柴油机先导泵先导阀司机

控制油

驱动工作油工作油

工作泵主控阀马达

工作油实现

实现工作装置工作油缸旋转、行走

Engine

Drive

Pilot pump

Control oilPilot valve

ControlDriver

Control oil

Work oilWork oilDrive

Work pump

Main valve

Work oil

Motor

Cylinder

Carry outCarry out

Swing、TravelImplement work

3

3.3 液压系统回路图 Hydraulic system schematic

3.3.1 负流量控制系统 Negative Flow Control System

BOOM RAISE 3.3.2 动臂上升Boom Raise

BOOM LOWER 3.3.3 动臂下降Boom Lower

ARM OUT

3.3.4 斗杆伸Arm Out

ARM IN

WITH REGENERATION3.3.5 斗杆收(带再生功能)Arm In (With Regeneration)

ARM IN

WITHOUT REGENERATION3.3.6 斗杆收(不带再生功能) Arm In (Without Regeneration)

BUCKET IN 3.3.7 铲斗收 Bucket In

M

BUCKET OUT 3.3.8 铲斗伸Bucket Out

SWING LEFT3.3.9 左回转Swing Left

SWING RIGHT3.3.10右回转Swing Right

FORWARD TRAVLE(HIGH SPEED) 3.3.11 前进(高速) Forward Travel (High Speed)

BACKWARD TRAVLE(LOW SPEED) 3.3.12 后退(低速) Backward Travel (Low Speed)

STRAIGHT TRAVLE

3.3.13 直线行走Straight Travel







Troubleshooting


4.1 主泵管路Main pump piping

压力传感器Pressure sensor

泄油管Case Drain hose

吸油钢管Oil inlet tube

工作管路Working hose

液压油温传感器Sensor for hydraulic oil temperature

电比例减压阀Solenoid ProportionalReducing Valve


920D(Ⅱ)、922D(Ⅱ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

4.2 回转马达管路Swing Motor Piping

工作油管Working hose


回转压力测压点Swing pressure test point

补油管Make up oil inlet

回转溢流阀Swing relief valve




920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)

4.2 回转马达管路Swing Motor Piping

工作油管Working hose


回转压力测压点Swing pressure test point

补油管Make up oil inlet

回转溢流阀Swing relief valve




923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

4.3 先导液压管路(先导阀块)Pilot hydraulic pipe line(Pilot valve block)

先导溢流阀Pilot relief valve

先导压力测试点Pilot pressure test point



先导滤芯Pilot filter


922D(Ⅲ)

先导压力测压点Pilot pressure test point


先导滤芯Pilot filter

4.3 先导液压管路(先导阀块)Pilot hydraulic pipe line(Pilot valve block)


920D(Ⅱ)、922D(Ⅱ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)








Troubleshooting


5.1 系统压力测试System pressure test

P1、P2口压力测试:(压力测试口a1、a2 ,规格：G1/4)Port P1、P2 pressure test:(pressure test ports a1、a2 dimension:G1/4)

1、用扳手拧开图中a1、a2处的螺塞并连上测压接头和压力表(压力表量程0～70MPa)；Remove the plug a1/a2 in the illustration with a spanner and connects with a pressure testing joint and a pressure gauge(with a range of 0~70MPa);

2、启动发动机，慢慢的操作挖掘机使油温增高到50±5℃左右，然后读压力表的读数；Start engine, Slowly operate the excavator to raise the hydraulic oil temoerature to 50±5℃;then read the data from the gauge;

3、拧下压力表和测压接头，用16Nm的扭矩拧紧螺塞。Remove pressure gauge and pressure testing joint.Tighten the plugs to a torque of 16Nm.

a1a2P2 P1


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

5.2 系统压力调整System pressure adjust

1、启动发动机，缓慢提高发动机转速到最高转速；Start the engine, increase it‘s rotating speed slowly to full speed ；

2、调整挖掘机上的显示器功能，使之位于检测左泵和右泵压力的状态；Set the excavator monitor to the function of cheking the left and right pump pressure;

3、放下先导操作手柄，操作工作装置使液压油温升高到50±5℃，然后操作动臂或斗杆伸出到行程末端位置，使安全阀打开。此时的压力值应为31.8~32.8MPa，再按下位于右操作杆上的按钮，压力值应为33.3~34.3MPa；

Turn on the pilot cutoff lever, operate the work implements to let the hydraulic oil temperature raises to 50±5℃, then operate the boom up or arm to extreme position to make the main relief valve open. At the moment the pressure value should be 31.8~32.8MPa, then press the burst button located on the right joystick, the pressure value should be 33.3~34.3MPa；

4、如果压力值不在以上的范围之内，我们需要按照以下的步骤进行调整：If the pressure values are not in the arrange above, we need to adjust them as following

procedure:(1) 用开口为30mm的开口扳手松开序号3锁紧螺母；

Loose locknut number 3 with open-end wrench(30mm);


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

(2) 按下右操作杆上的按钮，用6mm的内六角扳手向内或向外旋转序号4零件，同时观察显示器上的压力值，当达到33.3-34.3MPa时，停止旋转序号4零件并拧紧序号3零件，松开右操作杆上的按钮；

Press the burst button located on the right joystick ，turn number 4 slightly inwards or outwards slowly with inner hexagon spanner(6mm) and check the pressure value in the monitor.Stop turning number 4 when the pressure value reaches to 33.3-34.3MPa, then tighten number 3， loose the burst button located on the right joystick ;

(3)用开口为22mm的开口扳手逆时针松开序号5锁紧螺母，用6mm的内六角扳手向内或向外旋转序号4零件，同时观察显示器上的压力值，当达到31.8-32.8MPa时，停止旋转序号4零件并拧紧序号5零件。

Loose locknut number 5 with open-end wrench(22mm) in anticlockwise direction.Turn number 4 inwards or outwards slowly with hexagon spanner(6mm) and check the pressure value in the monitor. Stop turning number 4 and tighten number 5 when the pressure value reaches to 31.8~32.8MPa. 主安全阀

Main relief valve

5.2 系统压力调整System pressure adjust


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

5.3 先导压力测试Pilot pressure test

先导压力测试：压力测试口a3，规格G1/4Pilot pressure test and adjust:(pressure test port a3 dimension:G1/4)

1、用扳手拧开图中a3（序号466）处的螺塞并连上测压接头和压力表(压力表量程0～6MPa);Remove the plug a3（number466） in the illustration with a pressure testing joint and a spanner and connects with a pressure gauge(with a range of 0~6MPa);

2、启动发动机，慢慢的操作挖掘机使油温增高到50±5℃左右，然后读压力表的读数；Start engine, Slowly operate the excavator to raise the hydraulic oil temperature to 50±5℃;

3、在发动机转速在最高转速时，看压力表的读数，数值应在3.9~4.1MPa之间。Set the engine speed to full speed , check the pressure gauge,the value should be between 3.9~4.1MPa.

先导泵测压口a3The port of pilot pressure test a3


920D(Ⅱ)、922D(Ⅱ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

1、用手拧开图中序号2或序号4处的螺塞并连上压力表(压力表量程0～6MPa);Remove the plug number 2 or 4 in the illustration by hand and connects with a pressure gauge(with a range of 0~6MPa);

2、启动发动机，慢慢的操作挖掘机使油温增高到50±5℃左右，然后读压力表的读数；Start engine, Slowly operate the excavator to raise the hydraulic oil temperature to 50±5℃;

3、在发动机转速在最高转速时，看压力表的读数，数值应在3.9~4.1MPa之间。Set the engine speed to full speed, check the pressure gauge,thevalue should be between 3.9~4.1MPa.


920D(Ⅱ)、922D(Ⅱ)、922D(Ⅲ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

5.3 先导压力测试Pilot pressure test

5.4 先导压力调整Pilot pressure adjust

如果先导压力值不正确，请按以下步骤进行调整：If the Pilot pressure pressure value is incorrect, adjust it as following procedure:

(1)、用开口为22mm的开口扳手松开图中序号312锁紧螺母，用6mm的内六角扳手拧紧序号311螺钉，顺时针方向压力升高，逆时针方向压力降低,当压力值达到3.9~4.1MPa时，上紧锁紧螺母312，压力调整完成；Loose locknut 312 with open-end wrench(22mm)as shown in the illustration. Tighten screw 311 by inner hexagon spanner(6mm). The pressure will increase when rotate in clockwise direction and decrease when rotate in anticlockwise direction. Tighten locknut 312 when the pressure value reaches to 3.9~4.1MPa. After that, pressure adjustment is finished.

(2)、拧下压力表和测压接头，用16Nm的扭矩拧紧螺塞。Remove pressure gauge and pressure testing joint. Tighten the plug to a torque of 16Nm.

先导压力调整螺钉Pilot pressure adjust bolt


920D(Ⅱ)、922D(Ⅱ)、923D(Ⅱ)、925D(Ⅱ)、925D(Ⅲ)

5.4 先导压力调整Pilot pressure adjust

如果先导压力值不正确，请按以下步骤进行调整：If the Pilot pressure pressure value is incorrect, adjust it as following procedure:

(1)、松开先导溢流阀上的锁紧螺母，用内六角扳手拧紧先导溢流阀上的螺钉，顺时针方向压力升高，逆时针方向压力降低,当压力值达到3.9~4.1MPa时，上紧锁紧螺母，压力调整完成；Loose locknut that installed on the pilot relief valve as shown in the illustration. The pressure will increase when rotate in clockwise direction and decrease when rotate in anticlockwise direction. Tighten locknut 312 when the pressure value reaches to 3.9~4.1MPa. After that, pressure adjustment is finished.

(2)、拧下压力表和测压接头，用16Nm的扭矩拧紧螺塞。Remove pressure gauge and pressure testing joint. Tighten the plug to a torque of 16Nm.

适用机型 Model：

922D(Ⅲ)

先导溢流阀Pilot relief valve







Troubleshooting


6.1 液压元件动作缓慢Hydraulic components works slowly

原因 Cause 解决办法 Solutions

1 低油位Low oil level

给液压箱加油至充满记号Add oil to oil tank to the full mark

2 冷油Cold oil

开动发动机给液压系统加热Run the engine to preheat hydraulic system

3 错误的液压油Wrong hydraulic oil

使用正确的液压油Use the correct oil

4 发动机速度太慢Slow engine speed

解决发动机速度慢的问题Solve the problem of low engine speed

5 先导回路问题Pilot oil loops

检查先导回路Check the pilot circuit

6 泵磨损Worn pump

更换或修理损坏的零部件Replace or repair worn parts

7 泵吸油管受限制Restricted pump suction pipe

检查泵的吸油管路Check pump suction pipe

6.2 液压油过热Hydraulic oil over hot


1 错误的液压油Wrong hydraulic oil


2 低油位Low oil level

给液压箱加油至充满记号Add oil to oil tank to the full mark



4 堵塞的散热器或油冷却器Clogged radiator or oil cooler

清扫或整顿散热器翅片Clean or rearrange the radiator fins

5 油冷却器旁路Oil cooler bypasses

检查回油单向阀Check one-way valve of the oil return

6 溢流阀Relief valve

检查或调整溢流阀Check and adjust the relief valve

7 不清洁的液压油Unclean oil

排油之后重新加油Add oil after draining oil

8不适当的调整液压组件Improper adjustment for the hydraulic components

正确的调整液压组件Proper adjustment for the hydraulic components

6.3 低压或无油压Low pressure or no oil pres-sure


1 错误的液压油Wrong oil


2不适当的调整液压组件Improper adjustment for the hydraulic components

正确的调整液压组件Proper adjustment for the hydraulic components

3 系统内无液压油No oil in the hydraulic system

加进正确的液压油Add the correct oil

4 磨损的液压缸Worn cylinder


5 溢流阀Relief valve

检查或调整溢流阀Check and adjust the relief valve

6.4 液压缸工作但不能提升载荷Cylinder can work but can not lift load




2 主溢流阀压力低Low pressure of main relief valve

检查和调整主溢流阀压力Check and adjust the main relief valve pressure

3 液压油位低Low oil level

加液压油Add oil

4 吸油滤网堵塞Clogged the filter

清扫滤网和系统Clean the filter and the system

5 泵吸油管渗漏Pump suction pipeline leaks

检查吸油管Check suction pipeline

6.5 一个控制操作杆不工作One control lever does not work


1油口溢流阀压力过低Low pressure of the oil port relief valve

检查和调整油口溢流阀压力Check and adjust the oil port relief valve pressure

2 钢管或软管损坏Tube or hose damaged

修理或更换Repair or replace

3 液压装置松弛Hydraulic components loosen

拧紧Tighten

4 在装配中损坏O形圈O-ring is damaged when assembled

更换新O形圈Replace a new O-ring

5 先导阀Pilot valve

修理或更换先导阀上损坏的零部件Repair or replace worn parts of pilot valve

6 先导管路Pilot lines


6.6 一个液压缸不工作One cylinder does not work


1控制阀阀芯损坏或被灰尘污染 Spool of control valve damaged or polluted by dust

更换和修理主控阀损坏部件或清洗它Replace and repair worn parts of control valve or cleaning it

2 钢管或软管损坏Tube or hose damaged


3 液压装置松弛Hydraulic components loosen

拧紧Tighten

4 液压元件中的O形圈损坏O-ring of hydraulic components damaged

更换新的O形圈Replace a new O-ring


修理或更换先导阀上损坏的零部件Replace and repair worn parts of hand pilot valve or clean it

6 先导管路Pilot pipeline failure


6.7 一个行走马达不工作One travel motor does not work


1 行走马达Travel motor trouble

修理或更换行走马达上损坏的零部件

Replace and repair worn parts of travel motor or clean it

2 中心接头故障Center swivel joint trouble

检查中心接头是否内漏Check for internal leakageof center swivel joint

3 没释放驻刹车器Do not set free brake pedal

更换或修理驻刹车器Replace and repair brake

4 行走先导阀Travel pilot valve

修理或更换行走先导阀上损坏的零部件

Repair or replace worn parts of travel pilot valve or clean it

5 先导管路Pilot circuit


6.8 不能回转Can not swing


1 回转制动器释放阀Swing brake release valve

更换或修理回转制动器释放阀Replace and repair swing brake release valve

2 回转马达Swing motor

更换或修理回转马达上损坏的零部件Replace and repair worn parts of swing motor


修理或更换先导阀上损坏的零部件Replace and repair worn parts of hand pilot valve or clean it

谢谢！Thank you !

问题？Questions?

05液压系统hydraulic system.pdf

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