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1、Objectives 目标,Understand&study 了解及学习Hydraulic systems 液压系统Open Center Systems 开芯式系统Hydraulic Components 液压零件Basic Equations 基本公式CalculationsValidate calculation with measurements on 通过测量对SEM650的计算进行验证Specific objectives 特定目标?,Wheel Loader Power Flow,Rimpull,F x,F y,Torque Converter,Fan,Alternator,Ai
2、r Cleaner,Muffler(MEC,LEC)T=f(Engine Speed)Brake pump,Pilot pump,Steering pump,Transmission pump(H&HS)T=Disp*Pressure/Efficiency,Gross Engine Lug CurveMEC&LEC,Implement PumpH&HST=Disp*Press/Eff,Converter Data TBU,Power Flow 动力流动,Engine 发动机,Converter 变矩器,Implement Pumps 工作泵,Cooling Pump 冷却泵,Steering
3、Pump 转向泵,Implement Pilot Pump 工作先导泵,Brake Charging Pump 刹车辅助泵,Transmission Pilot Pump 变速箱先导泵,Rimpull 牵引力Wheel Speed 轮速,Lift Force/Speed 举升力/速度,Tilt Force/Speed翻转力/速度,Steering ForceSpeed 转向力/速度,Bucket ForceSpeed 铲斗力/速度,Brake Force 刹车力,Air Cleaner,Muffler,Alternator 空滤器，消音器，发电机,Fuel 燃油,Heat 热能,Energy
4、Distribution during Truckloading 9XX 9XX 装车应用时的能量分配,9XX 能量分配,32 秒钟装车周期,工作热能,转向热能,风扇热能,先导热能,变速箱泵热能,传动热能,刹车热能,车轮滑移热能,空滤器，消音器，发电机热能,发动机冷却热能,发动机排气热能,Focus Primary users of energy 焦点能量的主要使用者,Implement System 工作装置系统Powertrain System 传动系统,Hydraulics at Work,Hydraulics at Work,Hydraulics at Work,Hydraulics
5、at Work,http:/,Website with video,Implement System 工作系统,Open Center Systems 开芯式系统Main system 主要系统Pilot system 先导系统Implement valve function 工作阀功能Area curves 面积曲线Performance Characteristics 性能特性Math Modeling 数学建模Problems/Exercises 问题/练习Closed Center Systems 闭芯式系统Variable Implement Pump Controls 可变的工作阀
6、控制Load Sensing Circuits 负载敏感回路Problems/Exercises 问题/练习,Terminology,Industry&Academia tandem center valveMeans that in neutral the flow path fromPump to Cylinder-closedCylinder to Tank-closedPump to Tank openCaterpillar most Cat engineers call this an open center valveIndustry&Academia open center va
7、lveIn neutralPump to cylinder to tank all open,Hydraulic Schematics,3 Position Directional Control Valve,Pump,Variable Pump,Main Flow Lines,Pilot Lines,Solenoid Actuation,Pilot Actuation,http:/,For more see the following website:,Tandem Center Valve(Open Center at Cat),Pump,Tank,Head End,Rod End,To
8、Lift,Pump,Tank,Head End,Rod End,To Lift,Neutral,Dump,Tandem Center Valve(Open Center at Cat),Pump,Tank,To Lift,Pump,Tank,To Lift,Neutral,Rack,Head End,Rod End,Head End,Rod End,627 G Implement SystemTandem Center Interrupted Series,Main Relief,Apron(has float),Ejector,Bowl,Pump,SEM650 示意图Tandem Cente
9、r Interrupted Series,980H Implement Schematic Tandem Center(open)Interrupted Series,MainPump,Tank,988H Implement SchematicTandem(Open)Center Interrupted Series,MainPump,Tank,Pilot Supply,Tandem(Open)Center System,Work at white boardWhats wrong with this circuit?,Tandem(Open)Center Hydraulic System开芯
10、式液压系统,泵排放Pump Displacement=Dp泵速度Pump Speed=N泵容积效率Pump volumetric eff=Ev泵力矩效率Pump torque eff=Tv,缸头端压力面积Pressure area Head End=Phe缸杆端压力面积Pressure area Rod End=Pre冲程Stroke=S缸杆全收缩时长度Collapsed Length=Cl,x,质量Mass=m负载Load=mg阻尼Damping=c,面积Area=Apcre,面积Area=Apche,面积Area=Actre,面积Area=Acthe,面积Area=Apt,体积Volume
11、=Vhe压力Pressure=Phe,体积Volume=Vre压力Pressure=Pre,Valve Hardware阀硬件,Tandem(Open)Center Hydraulic ValveOperation开芯式液压阀操作,工作系统控制阀,主泵系统压力,先导压力,闭塞油路,吸油/回油,激活的零件,表面积,升起先导控 制执行器,补油阀,阀杆端,装载单向阀,阀头端,管路溢流 补油阀,降低先导控制执行器,降低执行器电磁阀,先导通道,至油箱,内部通道,供应通道,至油箱通道,至油箱,举升滤芯,举起执行器电磁阀,动臂保持不动,工作控制阀,阀杆端,装载单向阀,阀头端,补油阀,降低先导控制执行器,降低
12、执行器电磁阀,先导通道,至油箱,内部通道,供应通道,通往下一阀通道,至油箱,举升滤芯,举起执行器电磁阀,升起先导控制执行器,补油阀,主泵系统压力,先导压力,吸油/回油,激活零件,表面积,动臂下降时,988H Tilt Stem Characteristics,Pump to tank,Pump to cylinder RE,Cylinder to tank HE,Pump to cylinder HE,Cylinder to tank RE,988H Lift Stem Characteristics,Pump to tank,Pump to cylinder HE,Cylinder to t
13、ank RE,Cylinder to tank HE,Pump to cylinder RE,Raise,Lower,Tilt Valve Areas 翻斗阀面积SEM 650,卸料,输入,收斗,面积,Pump to tank,Pump to cylinder HE,Cylinder to tank RE,Pump to cylinder RE,Cylinder to tank HE,Raise,Lower,Boom Valve Areas 举升阀面积SEM 650,举升,输入,下降,面积,Pump to tank,Pump to cylinder HE,Pump to cylinder RE
14、,Cylinder to tank RE,Cylinder to tank HE,Pump Hardware Gear Pump,Pump HardwareVane Pump,Pump HardwarePiston Pump,Valve Port Slot阀口槽,Outlet Port出油口,Inlet Port进油口,Drive Shaft传动轴,Piston活塞,Swashplate 斜盘,Cylinder Block 缸体,WHERE,Are the components located on your machine?不同的零件在山工车上的分布？Next slide shows 992
15、 locations下一张幻灯片展示的是不同的零件在992上的分布,电子系统,先导液压系统,主要液压系统,两系统通用部分,工作液压泵,先导泵,可变泵电磁阀,电子-液压工作系统,先导溢流阀,工作电子控制组件,先导控制杆组件,主控制阀总成,翻斗缸,翻斗联接位置感应片,举升联接位置感应片,举升缸,液压油箱,Examine actual machine装载机现场调查,Work at Board 白板展示,Speed Control 速度控制Force Control 力的控制Feedback to operator 对驾驶员的反馈,Speed ControlFill in chart for a li
16、ght load and a heavy load速度控制完成轻载及重载图表,Input 输入,Speed速度,Force Control Fill in chart for a light load and a heavy load力的控制完成轻载及重载图表,Input 输入,Max Force 最大力,Basic Hydraulic Equations 基本液压公式,Continuity Sum of flows=0Flow TermsPumpCylOrificeLeakageMotorCompressibility连续性流量和=0流量术语泵油缸节流口泄漏马力可压缩性,Basic Hydr
17、aulic Equations 基本液压公式,Cylinder FlowCylinder of piston area Ah with speed of V.活塞缸面积 Ah，速度V Q=(dX/dt)*Ah=V*AhWhereQ-flow 流量Ah Area of Head End 缸头端面积V speed/velocity of cylinder 油缸速度(dX/dt)cylinder speed.油缸速度Orifice FlowOrifice of area A with pressure drop dP.节流口面积 A，压力下降 dPQ=A*Cd*sqrt(dP*2/)WhereQ f
18、low though an orifice 通过节流口的流量A area in mm2 面积Cd orifice coefficient=0.62 流量系数dP is the absolute pressure drop cross orifice in kPa Dp是通过节流口时的绝对压力下降，以kPa为单位Note:if flow is in l/min,DP is in Kpa,A is in mm2 and 注意：如果流量是以l/min为单位，DP以kPa为单位，A以mm2 为单位，The fluid is SAE10 then 流度就是SAE10Q=.0582*A*sqrt(dP),
19、Pump FlowPump with displacement Dp,volumetric efficiency,speed N.泵的排量 Dp,容积效率，速度NQ=Dp*N*WhereQ flow 流量Dp pump displacement 泵排量N shaft rotation speed 轴转速Motor FlowMotor with displacement Dm,volumetric efficiency,speed N.马达排量Dm，容积效率，速度 N Q=Dm*N/WhereDm is the motor displacement Dm为马达排量 N is the shaft
20、speed N为轴速Leakage Flow Leakage with leak coefficient K and pressure drop dP.泄漏系数 K及压力下降dPQl=k*dPCommpressibility Flow Flow need to raise the pressure of a volume V by dP over a time period of dT(compressibility).在一定时间段内，提高一定体积的压力所需的流量Q=(dP/dT)*V/WheredP/dT-Pdot=P/T V volume 容积-fluid bulk modulus 体积模
21、量/系数,Basic Force Equations 基本的力的计算公式,MomentumSum of forces=0Force/Torque TermsPump&MotorCylinder动量力的总和=0力/力矩术语泵&马达油缸,Basic Force Equations for hydraulic components 液压件的基本力的计算公式,Cylinder of piston area Ah.活塞缸面积AhF=(P)*Ah WhereP=Pressure 压力Ah=Area of Head End 缸头端的面积 Pump 泵 T=Disp*dP/WhereT=Torque to d
22、rive pump 驱动泵的力矩dP=pressure across pump 穿过泵的压力=torque efficiency 力矩效率,Motor 马达 T=Disp*dP*WhereT=Torque to drive motor驱动泵的力矩dP=pressure across motor穿过泵的压力=torque efficiency力矩效率,Summary,Open Center System ComponentsFixed displacement pumpsValves with pump to tank,pump to cylinder,cylinder to tank area
23、sMain&line relief valvesLoad ChecksMake ups&back pressure valvesOperator control featuresAbility to limit system pressure with the leverTool speed changes with load operator has a“feel”for loadDeadband varies with engine speed and load pressureMulti-function operation generally is done with interupt
24、ed series valve where upstream functions have full priority over downstream functions,Form small teams to work problemsNeed to stagger groups to work on machine tests分成小组解决问题需要交叉小组进行整车测试,Fundamentals Open Center SystemsExercise 基础知识-开芯式系统练习,What is the purpose of the following components in an open
25、center system?以下所列零件在开芯式系统中有什么用途？Main Relief?主安全阀？b)Load check valves?装载单向阀?d)Line reliefs?管路溢流阀？e)Make up valves?补油阀？f)Pressure control valve in the tank return line?油箱回油线路中的压力控制阀？,Fundamentals Open Center Systems基础知识-开芯式系统,Compute the lift time for your machine assuming the cylinder goes through i
26、ts full stroke,a pump efficiency of 90%,a full lift command,and rated engine speed.假定油缸是在全冲程状况下，泵抽效率为90%，全举升，发动机在标准转速下工作，计算整车的举升时间。3.Compute the lower time for your machine assuming the load is driven and not overrunning and the operator is asking for full lower.Also assume the cylinder goes through
27、 its full stroke,a pump efficiency of 90%,a full lift command,and rated engine speed.假定车是负载但是并不超载，并且驾驶员要进行全下降时，计算整车的下降时间。仍然是假定油缸是在全冲程状况下，泵抽效率为90%，全举升，发动机在标准转速下工作。,Fundamentals Open Center Systems基础知识-开芯式系统,Compute the lower time for your machine assuming the load is overrunning,the head end pressure
28、 is 4000 Kpa,and the cylinder to tank area is at its maximum.If you know the pressure to hold the load on your machine use that pressure rather than 4000 Kpa.Note that on loaders the pressure varies significantly with linkage position.假设车是超载的，杆头压力是4000Kpa，油缸到油箱的面积最大时，计算整机的下降时间。计算时，忽略掉快速下降阀。如果知道你的机器的
29、支撑载荷时的压力，使用此压力而不要用14000Kpa的压力。Chinese needs edited5.What must the cylinder to tank area be in order to have a lower time of 3 seconds assuming an overrunning load and still assuming the head end pressure is 4000 Kpa(or your known pressure)?假定在超载情况下并且杆头压力仍然是4000Kpa（或是你已知的压力）时，要达到3秒钟的下降时间，油缸到邮箱的面积必须是多
30、少？6.What is the max force that can be generated by the lift cylinders in the raise direction if the cylinder efficiency is 90%?油缸效率为90%时，举升缸在举升方向所能产生的最大的力是多少？7.What is the max force that can be generated by the lift cylinders in the lower direction if the cylinder efficiency is 90%?油缸效率为90%时，举升缸在降落的
31、方向所能产生的最大的力是多少？,Fundamentals Open Center Systems基础知识-开芯式系统,What is meant by the term“hydraulic modulation”?什么是“液压调制”？9.Can an operator use engine speed to gain hydraulic modulation with an open center system?Explain your answer.驾驶员可以利用发动机转速在开芯式系统中来获取液压调制吗？解释一下你的答案。10.How does the gain of cylinder mo
32、tion to tool motion impact hydraulic modulation?油缸的机械运动到工作装置机械运动的增加/获取是怎么来影响液压调制的?,Fundamentals Open Center Systems基础知识-开芯式系统,What determines the valve spool deadband for an open center circuit with a resistive load?If your machine has an open center circuit how much is the deadband for one of the c
33、ircuits?Compare your estimate to measured data from PPG or to data from a Dynasty model or both.什么决定了带有阻力载荷的开中位回路的阀芯死区?如果你们的车有一个开中位回路,那么其中一个回路的死区是多少?比较一下你的估计数字和从PPG里或者从Dynasty模型或者同时从两者中测得的数字 12.What determines the valve spool deadband for an overrunning load condition?How much is the deadband for on
34、e of the circuits on your machine?Compare your estimate to measured data from PPG or to data from a Dynasty model or both.在超载条件下,是什么决定了阀芯的死区?其中一个回路的死区是多少?比较一下你的估计数字和从PPG里或者从Dynasty模型或者同时从两者中测得的数字,Fundamentals Open Center Systems基础知识-开芯式系统,If you had a conventional open center hydraulic system and de
35、sired the operator to see no variation in deadband at the lever when moving resistive loads what variables would your control algorithm need to compensate for?如果你有一个常规的开芯式系统而且想在移动阻力载荷的时候，驾驶员在控制杆处不会看见任何的死区的变动，你的控制运算法则需要什么变量来补偿？14.What is a simple test you can do to determine if a cylinder is voiding
36、during a gravity driven function?How can you compute the amount of the void?How can you compute the time needed to fill the void?Perform these calculations and run the simple test on your machine.Compare your calculated times to the measured ones.什么样的简单试验可以确定在重力驱动功能期间，油缸是否有空隙？你怎么来计算空隙的数量？你怎么来计算填充空隙所
37、需要的时间？进行计算并且在你的机器上进行此简单实验。将你计算出的时间和所测的时间进行比较,Fundamentals Open Center Systems基础知识-开芯式系统,Most conventional wheel loader open center systems use interrupted series valves.What does this mean?If the operator pulls the tilt lever and the lift lever to their full displacements what are the resulting moti
38、ons?大多数常规装载机的开芯式系统使用中断式系列阀.这代表什么意思呢?如果驾驶员把摇臂及动臂拉到全位移时,产生的机械运动是多少?,Machine Tests整车测试,Machine Tests 整车测试,Observe the modulation characteristics of your machine.How much deadband is there in the lever?Does it change with engine speed?Does it change with load(note if you cant get a load compare deadband
39、 with the linkage low versus high the lift pressure will be higher when the linkage is raised).Dump the bucket so you can clearly see the cutting edge.What is the minimum distance you can move the bucket?For your machine:对于你的车a)Calculate the lift time with the engine at HI.计算一下举升时间,当发动机处于高速运转时b)Meas
40、ure the lift time for your machine.测量一下举升时间c)Compare the values from a and b.How different are they?What factors might contribute to the differences?比较一下a 和 b的值.它们有多大的区别?什么因素导致此诧异的产生?Repeat step 1 with the engine at a lower speed perhaps half throttle.重复第一项的操作当发动机低速运转时?-可使用半油门,Machine Tests 整车测试,For
41、 your machine:对于你的车Calculate the lower time assuming a pumped load and repeat assuming an overrunning load.假设是泵载荷且超载时，计算下降时间What is the actual lower time on the machine?实际的下降时间是多少?From this time and your previous calculations can you determine if it is overrunning or pumped?If your machine has a qui
42、ck drop valve,how does it influence this time?通过以上两个时间信息，你能决定是超载荷还是泵载荷吗？如果你的车上装有快速下降阀的话，它是怎么影响这个时间的？What is a simple test you can do to determine if a cylinder is voiding during a gravity driven function?How can you compute the amount of the void?Run the simple test on your machine and perform these
43、 calculations.什么样的简单试验可以确定在重力驱动功能期间，油缸是否有空隙？你怎么来计算空隙的数量？你怎么来计算填充空隙所需要的时间？进行计算并且在你的机器上进行此简单实验。将你计算出的时间和所测的时间进行比较(Chinese needs edited),Machine Tests 整车测试,Repeat step 4 with the engine at a lower speed perhaps half throttle.重复第四项的操作当发动机低速运转时-可使用半油门,Load Sensing 加载敏感的,Variable Pump System变量泵系统,Efficien
44、cy 效率,Pressure 压力,Flow流量,Cylinder or Output Power缸或输出功率,Power Wasted inFixed Displacement Pump System 固定活塞泵系统中功率的损耗,Pressure 压力,Flow流量,Cylinder or Output Power=0缸或输出功率=0,Power Wasted inFixed Displacement Pump System固定活塞泵系统中功率的损,During modulation调制期间,During stall 失速期间,Relief 溢流,Modifications to go fr
45、om Open Center Hydraulic System toClosed Center Hydraulic System开芯式系统到闭芯式系统的变更,泵排量Pump Displacement=Dp max泵速度Pump Speed=N泵容积效率Pump volumetric eff=Ev泵力矩效率Pump torque eff=Tv,面积Area=Apcre,面积Area=Apche,面积Area=Actre,面积Area=Acthe,Area=Apt,体积olume=Vhe压力Pressure=Phe,体积Volume=Vre压力Pressure=Pre,Also need to a
46、dd pump controlsEither electronic or hydromechanical同样需要增加泵控制-电子的或者液压机械的,Valve Port Slot阀口槽,Outlet Port出油口,Inlet Port进油口,Drive Shaft 传动轴,Piston活塞,Swashplate 斜盘,Cylinder Block 缸体,Click to play movie,Variable Displacement Piston Pump 可变活塞泵,Pump Controls High Pressure Cut Off泵控制-高压截止,Pump controls sens
47、e pump discharge pressure 泵控制感应泵释放压力and destroke pump at high pressure,High Pressure Cut Off 高压截止,面积Area=Apcre,面积Area=Apche,面积Area=Actre,面积Area=Acthe,Pressure 压力,Command to achieve flow 完成流动命令,Main valve is modified to send tank pressure to pump control when valve is in neutral andcylinder pressure
48、to pump control when functionis in use.当阀处于零位时，主阀被更改用来将油箱压力发送到泵控制;当功能在使用时,将油缸压力发送到泵控制.The pump control adjusts swashplate angle to maintain a pressure drop from pumpto pressure signal.泵控制调整斜盘角度来维持泵到压力信号的压力的下降。This means that when the function is in use margin pressure is held constantacross the pump
49、 to cylinder area.这就意味着当功能在使用时,边缘压力在泵到油缸区保持为常量,Pump Controls Load Sensing泵控制 负载敏感的,Load Sensing Control 载荷敏感控制,面积Area=Apcre,面积Area=Apche,面积Area=Actre,面积Area=Acthe,Pressure 压力,Delta Pressure Delta 压力,Flow 流量,Command to achieve flow 完成流动命令,If Op Cmd=0 P=P tank 油箱If Op Cmd is non zero P=P cylinder 油缸,P
50、ressure 压力,Pressurefrom workingFunction 来自工作功能的压力,Operator Command 驾驶员命令,-,Physical Locations of Controls,Load sensing control and high pressure cut off on the pumpSignal network in the implement valveSignal line sends signal from valve to pump,Return to tank,Signal to pump,Case drain,Suction,Tank,I
