液压与气压传动(英汉双语)第2版-教学ppt课件

Hydraulic and pneumatic pressure transmissionChapter 9 Design of Hydraulic Transmission SystemChapter 9 Design of Hydrau9.1 The Approach for Design of Hydrostatic Circuits9.2 A Design Example of Hydraulic SystemsChapter list9.1 The Approach for Design of Introduction The design of hydrostatic transmission systems is an important part of the whole mechanical design and also a summarizing and comprehensive application of knowledge in previous chapters.The aim of this chapter is to show through an example how hydrostatic transmission circuits can be designed to satisfy a given set of requirements.Introduction9.1 The Approach for Design of Hydrostatic systems 9.1.1 Determination of design requirements9.1.2 Analysis for working conditions and determination of main parameters9.1.3 Determination of hydraulic system diagram9.1.4 Calculation and selection of hydraulic components9.1.5 Performance check for a hydraulic system designed9.1.6 Drawing of working diagrams and technical documents9.1 The Approach for Design ofFig.9-1 General design process for a hydraulic transmission system Fig.9-1 General design process9.1.1 Determination of design requirements Before a hydraulic system is designed,the working conditions of the mainframe in the mechanical equipment must be analyzed.1.The purpose of the mainframe,the overall arrangement,the limitations to the position of the hydraulic devices and their sizes.2.The mainframe work cycle,the system actions,their sequence,interlock function,automatization.3.The load on actuators and the ranges of speed,motion stability,position accuracy,conversion accuracy,etc.4.Working environment and working conditions.5.Working efficiency,safety,reliability,cost,etc.9.1.1 Determination of design 1.Analysis of working conditions 1 1）Dynamic parameters analysis A load diagram can be drawn out based on the determined extrinsic loads,see Fig.9-2a,which is load chart.The load chart is actually a load-displacement（F-l）curve.9.1.2 Analysis for working conditions and determination of main parameters1.Analysis of working conditio a)Load chart b)Speed chart Fig.9-2 Load chart and speed chart of actuators 1-Startup acceleration 2-Quick feed 3-Working feed 4-Brake 5-Friction 6-Cutting force 7-Seal and back pressure resistance 8-Inertia force a)Load chart (2)Movement parameters analysis Fig.9-2b is a speed-displacement（v-l）curve drawn to express the speed of each actuator in different phases,it is called speed chart.When the actuator works in line reciprocating,the extrinsic load will be(9-1)1)The working load(2)Movement parameters analysi2)The friction resistance force(9-2)3)The inertia load Besides three loads mentioned above,an actuator stands also viscosity resistance force,sealed resistance force and back pressure resistance etc.(9-3)2)The friction resistance for2.Determination of main parameters The working pressure for actuators can be selected according to the largest load in the load chart(see Tab.9-1)or the mainframe type(see Tab.9-2).However the largest flow rate must be calculated by the highest speed shown in the speed chart.The lowest working speed must satisfy the following requirements:For cylinders For motors 2.Determination of main paramTab.9-1 Working pressure selected for an actuator according to loadLoadF（N）50000 Working pressure p（MPa）0.81 1.52 2.53 3445 57 Tab.9-2 Working pressure selection for an actuator according to mainframe typeMainframe type Machine tools Agricultural machinery,small-sized engineering machinery,auxiliary devices for engineering machinery Hydraulic press,large-sized excavator,heavy machinery,lifting and conveying machinery Grin-derModular machine toolsPlaner Drawing benchWorking pressurep（MPa）235 8810 1016 2032 Tab.9-1 Working pressure selec3.Drawing of working condition chart of the actuators After the structure parameters of the actuators are determined,the practical working pressure,the flow rate and the power can be calculated according to the design task and its requirements.Then pressure(flow rate,or power)time(or displacement)curves can be drawn out,as shown in Fig.9-3.Fig.9-3 Working condition chart of actuators 1-Startup acceleration 2-Quick feed 3-Working feed 4-Brake 3.Drawing of working conditio9.1.3 Determination of hydraulic system diagram1.Analysis and selection of the hydraulic scheme2.Analysis and selection of the hydraulic circuits3.Determination of hydraulic system diagram9.1.3 Determination of hydraul9.1.4 calculation and selection of hydraulic components1.Selection of pumps According to maximum working pressure and provided flow rate calculated above,a proper pump can be selected from product samples.For the sake of safety,the chosen pump must be with a rated pressure 20%60%higher than the maximum working pressure(described above)for pressure reserve,but with a rated flow rate just meeting the maximum flow rate to avoid an exceeding loss of power.2.Selection of valves9.1.4 calculation and selectioTab.9-3 Experiential values of the pressure loss in the inlet oil line System configuration Overall pressure loss(MPa）Simple system with general throttle speed-regulating components and pipelines 0.20.5Complex system with speed-regulating valves and pipelines 0.51.53.Selection of valve arrangementsThere are three types of arrangements for hydraulic equipments(1)Modular type(2)Manifold plate type(3)Integrated block Tab.9-3 Experiential values of9.1.5 Performance check for a hydraulic system designed1.Checking of the system pressure loss The pressure loss includes frictional loss along the pipelines,local loss in the pipelines and to a less produced by the valve components.The pressure loss of along or local can be calculated from the involved expressions shown in Chapter 2,while the local loss of the valve components can be obtained from the product samples.When the practical flow rate q of a valve component doesnt equal the nominal flow rate（9-4）9.1.5 Performance check for a 2.Checking of the temperature rise caused by heat generation according to heat balance principle,when the dimension ratios of three sides of the reservoir are between 1:1:1 and 1:2:3,the oil lever is 80%that of the reservoir height,and the reservoir is in good ventilation Condition,then（9-5）Once the checked oil temperature rise surpasses the allowable value,a proper cooler must be set in the system.The allowable oil temperature rise in the reservoir is different for different mainframes 2.Checking of the temperature9.1.6 Drawing of working diagrams and technical documents The working diagrams usually incorporate hydraulic system figure,assembly drawing and the assembly and part Drawings.There must exist a list of components attached to the hydraulic system figure.The system assembly figure is the construction and erection drawing for the hydraulic system.Generally,the technical documents include the explanations of design calculation,manual to use and maintain,content of parts,standard parts,universal parts,overall table of outsourcing parts,etc.9.1.6 Drawing of working diagr9.2 A Design Example of Hydraulic Systems9.2.1 Analysis of working conditions9.2.2 Determination of main parameters of the actuator9.2.3 Design of hydraulic systems9.2.4 Selection of hydraulic components9.2.5 Performance check for hydraulic systems9.2 A Design Example of Hydrau This section is to study the hydraulic system of a single side multi-spindle drill machine tool.axial cutting force overall gross weight G（N）Distanc-es covered at rapid speed Distanc-es covere-d at work speed the rapid feed and retract velocity work feed velocity time for acceleration and deceleration friction coeffici-ent of rest friction of motion Mechan-ical efficienc-y of the cylinder 3000095001005050.050.20.20.10.9 The dynamic slipway is required to achieve such a work cycle:rapid feed work feed block dwell rapid retract stop at the original position.This section is to study t9.2.1 Analysis of working conditionsThe axial cutting force which is also the only force whose direction is horizontal.Then the inertia force,the friction of rest and the friction of motion against the guide way can be calculated as follows9.2.1 Analysis of working condTab.9-4 Loads on the cylinder in each work step Working conditionLoad combinationLoad F（N）Thrust Startup 19002111Acceleration 13541504Deceleration 9501056Work feed 3095034389Rapid retract 9501056 The loads on the cylinder in each work step are listed in Tab.9-4,where the back pressure in the oil returned chamber is neglected.The load and speed diagrams are indicated in Fig.9-4a and Fig.9-4b.Tab.9-4 Loads on the cylinder a)Load b)Speed Fig.9-4 Load and speed diagrams of the cylinder a)Load 9.2.2 Determination of main parameters of the actuator1）system pressure3）area of cylinder2）back pressure The cylinder area can be calculated from the thrust at work feed period:9.2.2 Determination of main paThen D and d must be corrected to standard values according to GB 23481997：,then the practical effective areas of the two chambers of the cylinder are The pressure,flow rate and power at each work step as shown in Tab.9-5.The working conditions chart can then be drawn,as indicated in Fig.9-5.Then D and d must be correctedTab.9-5 The pressure,flow rate and power at each stepTab.9-5 The pressure,flow ratFig.9-5 Working conditions diagram Fig.9-5 Working conditions dia9.2.3 Design of hydraulic systems1.Selection of hydraulic circuits2.Design of hydraulic systems3.Selection of the hydraulic valves9.2.3 Design of hydraulic systFig.9-6 Principle chart of hydraulic systemFig.9-6 Principle chart of hydFig.9-7 Principle chatr of hydraulic system with modular valvesFig.9-7 Principle chatr of hyd9.2.4 Selection of hydraulic components1.Pumps1）pressure2）flow rate The maximum flow rate provided by the two pumps is 25.13L/min.If the leakage in the return line is supposed 10%the input flow rate of the cylinder,then the overall flow rate of the two pumps is9.2.4 Selection of hydraulic c From the pressure and flow rate calculated above,the PV2R12-6/26 type pair vane pump can be adopted,The deliveries of the small pump and the large pump are 6mL/r and 26mL/r respectively.3）motor According to involved motor product contents,we can select the Y100L-6 type motor.From the pressure and 2.Valves and auxiliary elementsThe valves and auxiliary elements can be selected according to the system working pressure and the practical flow rate through them,see Tab.9-6 and Tab.9-7.3.Pipelines According to YB 231-1970,we can choose the 15-sized cold-drawn seamless steel tube which has an inner diameter of 15mm and outer diameter of 18.2mm.2.Valves and auxiliary elemenNumberNameFlow rate estimated（L.min-1）Type and specification1Filter 30XU-J63X80 2Pair vane pump5.1+22PV2R-6/263Pressure gauge switch-KF3-E3B4Check valve 25AF3-Ea10B 5Pressure relief valve5YF3-E10B 6Five-way,three-position solenoid valve6035DY-E10B 7Check valve 60AF3-Ea10B 8Pressure switch-PF-B8L 9Stroke valve50AXQ-E10B 10Speed control valve0.511Check valve 6012Check valve 25AF3-Ea10B 13Back pressure valve0.5YF3-E10B 14Hydraulic-controlled sequence valve 25XF3-E10B Tab.9-6 Types and specification of the components NumberNameFlow rate estimated NumberNameFlow rate estimated（L.min-1）Type and specification1Filter 30XU-J63X80 2Pair vane pump5.1+22PV2R-6/263Soleplate block 27.1EDKA-10 4Pressure gauge Y-100T 5Pressure gauge switch-4K-F10D3 6Pressure switch-PD-F10D3-A 7Hydraulic-controlled sequence valve 25X-F10D3-P/T(P1)8Pressure relief valve5Y1-F10D3-P/T 9Electromagnetic speed control check valve-Q1AD-F6/10D3-B 10Check valve 25A-F10D3-T 11Back pressure valve0.5PA-Fa6/10D3-B(A)12Check valve 25A-F10D3-T 13Check valve 60A-F10D3-T 14Five-way,three-position solenoid valve6035DY-E10B Tab.9-7Types and specification of the components(modular valves)NumberNameFlow rate estimated Tab.9-8 Input and output flow rate of the cylinder Tab.9-8 Input and output flow4.Reservoirs The volume of the reservoir can be estimated from ,where is by experience,then：V can be corrected to a standard value of 250L according to GB 28761981.9.2.5 Performance checking of this hydraulic systems1.Pressure loss2.Oil temperature rise4.Reservoirs The volume ofyour suggestions are welcome!The Endyour suggestions are welc液压与气压传动(英汉双语)第2版-教学ppt课件