机械制造技术基础双语第2章课件.ppt

1、2022-8-4河南科技大学机电工程学院12.1 Introduction 1)Lathe2)Milling machine3)Drilling machine4)Planer and Shaper5)Grinding machine6)Boring machine7)Broaching machine8)Threading machine9)Gear cutting machine10)Sawing machine11)Others 2022-8-4河南科技大学机电工程学院22.1 IntroductionBased on the degree of specialization Gener

2、al purpose machine toolsSpecialized machine toolsSpecial purpose machine tools Based on the weight of machine toolsLight-duty machine tools Medium-duty machine tools Large-duty machine(10t)Heavy-duty machine(30t)Super-heavy duty machine(100t)2022-8-4河南科技大学机电工程学院32.1 IntroductionStandard accuracy,pre

3、cision machine tools and high precision machine tools.Automatic machine tool and semi-automatic machine tool Multi-spindle machine tool,multi-cutter machine tool In general,machine tools are classified based on the machining feature firstly,and then described further based on some characteristics,su

4、ch as semi-automatic&multi-cutter machine tool,universal cylindrical grinding machine with high precision.2022-8-4河南科技大学机电工程学院42.1 IntroductionPlanning of machine tool modelThe expression of general purpose machine tool model is as follows:company code the number of spindle or second primary paramet

5、er primary parameterseries code Group codegeneral/structure feature codeClassified codeSub-classified codeOtherCharacteristiccodeSignificantImprovingSequencecode2.1 IntroductionFig.2-1 Expression of general-purpose machine tool model 2022-8-4河南科技大学机电工程学院62.1 Introduction Several basic surface forms:

6、plane,cylindrical surface,threads,contoured surface,involute surface.It can be seen that these surfaces are generated by moving a along a.In general,the and the can be interchanged.For the special surfaces,the two line cant be interchanged.Both parent line and guide line are generally called generat

7、ing lines.2022-8-4河南科技大学机电工程学院72.1 IntroductionMethods of generating surfaces Fig 2.1 Forming of workpiece surface1)Tracing2)Forming2022-8-4河南科技大学机电工程学院82.1 IntroductionMethods of generating surfaces Fig 2.2 Methods to produce generating line1)Tracing2)Forming3)Tangent tracing4)Generating2022-8-4河南科

8、技大学机电工程学院92.1 Introduction Generally,the surfaces to be machined is produced by forming or by generating or by a combination of these two fundamental methods.Generating is where the required profile is obtained by manipulating the relative motion of the workpiece and cutting edge.In forming,the shap

9、e of work produced is direct replica of the cutting tool.Thus the accuracy of the shape obtained is dependent on the accuracy of the form cutting tool.2022-8-4河南科技大学机电工程学院102.1 Introduction 1)Motions of machine tool(1)Surface forming motion a)Simple forming motion means that a independent forming mo

10、tion includes single rotation or a linear motion.(车外圆、刨平面车外圆、刨平面)2022-8-4河南科技大学机电工程学院112.1 Introductionb)Compound forming motion means that a independent forming motion consists of two or more rotations or linear motions.(车螺纹)(2)Auxiliary motiona)Engaging and disengaging;b)Changing the speed of driv

11、e and feed motion;c)clamping and loosening of workpiece;d)Indexing motion;2022-8-4河南科技大学机电工程学院122.1 Introduction2)The motion connection of machine tool.Machine tools must be of three basic parts to realize various motions required in machining process.They are:Executive elements:such as spindle,tool

12、 rest,working table etc.;Power source:such as motors;Transmitting devices,which are used to transmit power and motion.2022-8-4河南科技大学机电工程学院132.1 Introduction The transmission connection composed of power sources-transmitting devices-executive members or of executive members is called transmission cha

13、in.There are two kinds of transmission chains:External-connection transmission chain Internal-connection transmission chain2022-8-4河南科技大学机电工程学院142.1 Introduction (1)External-connection transmission chain This transmission chain connects the executive members with power source(motor),having the execu

14、tive member get a certain speed and moving direction.The change of transmission radio affects only the productivity or surface finish and doesnt affect the component shape.Therefore,there can be some friction transmission with inaccurate transmission ratio.2022-8-4河南科技大学机电工程学院152.1 Introduction (2)I

15、nternal-connection transmission chain This chain connects one executive member with another.Since it determines the trace of compound motion(the shape of generating line),there are serious requirements for the relative velocity between the connected executive members in the chain.Therefore,the trans

16、mission ratio between the transmission members must be accurate.There shouldnt be any friction transmission member or other transmission pairs with the variation of instantaneous transmission ratio,such as belt drive and chain drive.2022-8-4河南科技大学机电工程学院16请在这里添加章节标题 YouYou are are WelcomeWelcome2022-

17、8-4河南科技大学机电工程学院172.2 Lathes and lathe cutters Most lathes are capable of performing both external and internal machining operations.External cylindrical machining operations include straight turning,taper turning,turning grooves,facing,threading,knurling and cutting off (parting off)stock.Internal c

18、ylindrical machining operation include all common hole-machining operations such as drilling,boring,reaming,counterboring,countersinking,center drilling,tapping and threading with a single-point cutting tool.2022-8-4河南科技大学机电工程学院182.2 Lathes and lathe cuttersFig.Lathe operations2022-8-4河南科技大学机电工程学院19

19、Constructional Feature of a Center Lathe n1.Components of Lathe(CA6140)Headstock Tailstock Carriage Compound rest Feedbox Apron Bed Base2.2 Lathes and lathe cutters2022-8-4河南科技大学机电工程学院20n2.Transmission system of Lathe(CA6140)(1)Transmission system diagram of machine tool2.2 Lathes and lathe cutters

20、of the machine tool is generally used to analyze the transmission situation of a machine tool.is a sketch map used for indicating all machine tool motions.In the drawing,a specific drive mechanism of a transmission chain is expressed by simple prescribed symbol,and tooth number of gear and worm gear

21、,thread number of worm,lead of screw,pulley diameter,power and revolution of electric motor should also be marked on a specific drive member.The drive mechanisms in tTransmission System Diagram is made in the form of development drawing in the outline contour of machine tool.2022-8-4河南科技大学机电工程学院21nA

22、 Primary Transmission System Diagram2.2 Lathes and lathe cutters2.Transmission system of center lathe(2)Block diagram of lathe transmission system PulleyHeadstockSpindleChuckWork rotationEnd gearboxFeed gearboxLead screwCarriageThreadingMotorFeed rodCarriageLongitudinalOr cross motionFig.Block diagr

23、am of lathe transmission system2.2 Lathes and lathe cutters2022-8-4河南科技大学机电工程学院23n2.Transmission system of Lathe(CA6140)(2)Block diagram of lathe transmission system2.2 Lathes and lathe cuttersPulley带轮Headstock主轴箱Spindle主轴Chuck卡盘Work rotation工件转动End gear-box挂轮箱Feed gearbox进给箱Lead screw丝杠Carriage大拖板T

24、hreading车螺纹Motor电动机Feed rod光杠Longitudinal/cross motion纵/横向运动Carriage大拖板2022-8-4河南科技大学机电工程学院24n(3)Transmission system diagram of Lathe(CA6140)2.2 Lathes and lathe cuttersTransmission System Diagram（CA6140）2022-8-4河南科技大学机电工程学院25n2.Transmission system of Lathe(CA6140)(3)Transmission system of the lathe

25、 CA61402.2 Lathes and lathe cutters Lathe must have two motions:one is the rotary motion of workpiece-primary motion;the other is the linear motion of cutter-feed motion.In order to realize these motions,the transmission system of lathe should have as follows：a)to realize primary motion；b)to realize

26、 longitudinal feed motion；to realize feed transverse motion.1)Transmission route130Motor230M1(left)56/3851/43M1(right)50/3434/3039/4130/5022/5820/8051/50-20/8051/50 26/58 M263/50(Spindle)Lecture 72.2 Lathes and lathe cuttersn3.To analyze the transmission system of Lathe(CA6140)(1)Transmission chain

27、of primary motion2022-8-4河南科技大学机电工程学院272.2 Lathes and lathe cuttersIt can be seen from primary drive system diagram that)A multi-piece friction clutch M1 is assembled on shaftto make spindle rotate counter-clockwise and clockwise,and stop.)Join of gear to shaft with single fixed key(fixed gear),spli

28、ne(sliding gear),smooth surface；)The sliding gear Z50 on spindle is shifted to right end to mesh with M2.Spindle can obtain low revolution with 10r/min500r/min；)When M2 is disengaged,the motion is directly transmitted to shaft from shaft.Spindle can obtain 6-level high revolution with 450r/min1400r/

29、min。2022-8-4河南科技大学机电工程学院282.2 Lathes and lathe cuttersMotion balance equation:uuunnms)1(230130sliding coefficient of V pulley，=0.02；u-Variable drive ratio between shaft I and shaft.The rest can be deduced similarly.2022-8-4河南科技大学机电工程学院292.2 Lathes and lathe cutters2)Revolution series and revolution

30、of spindleHigh speed transmission route It can be seen from the transmission route that the spindle can get six high speeds when it rotates counter clockwise(2x3=6)from 450r/min to 1400r/min.2022-8-4河南科技大学机电工程学院302.2 Lathes and lathe cutters Low speed transmission route.Theoretically,the spindle can

31、 get 24 levels(2322)low speed.In fact,it can only get 18-level low speed.This is because i1=20/8020/80=1/16,i2=50/5020/80=1/4,i3=20/8051/501/4,i4=50/5051/50 1.As i2i3,the real revolution levels are:23(22-1)=18.2022-8-4河南科技大学机电工程学院312.2 Lathes and lathe cuttersRPM levels in clockwise rotation.It is c

32、lear that the RPM levels in clockwise rotation are 3(1+22-1)=12 Generally,clockwise rotation is not used for cutting.It is used to return lathe cutter to starting point along thread in threading under disengaging the drive relation between spindle and tool rest.The revolution in clockwise rotation i

33、s higher so as to reduce auxiliary time.Limit revolutionrpmnrpmn105826802080205822435198.02301301450140050634139385698.02301301450minmax2022-8-4河南科技大学机电工程学院322.2 Lathes and lathe cutters2022-8-4河南科技大学机电工程学院33请在这里添加章节标题 YouYou are are WelcomeWelcome2022-8-4河南科技大学机电工程学院34n2)Transmission chain of feed

34、motionv Its functions is to make tool rest move longitudinally or transversely at required speed.It consists of threading transmission chain and power-driven feed transmission chain.2.2 Lathes and lathe cuttersspindletool restReview2022-8-4河南科技大学机电工程学院352.2 Lathes and lathe cuttersn(1)Threading tran

35、smission chain.n The lathe CA6140 can be used to machine 4 kinds of standard threads:metric system,British system,module thread and diametral pitch thread,no matter whether it is right-hand or left-hand.It can also be used to machine large lead threads,not standard threads and precision threads.n To

36、 cut an accurate thread,it is essential to maintain the correct relationship between the movement of the carriage and the RPM of the work.This can be achieved by means of the lead screw,which is driven by a train of gears from the spindle.2022-8-4河南科技大学机电工程学院362.2 Lathes and lathe cutters1r workL to

37、ol(mm)Motion balance equation:1spindleuLthread LWORK 2022-8-4河南科技大学机电工程学院372.2 Lathes and lathe cuttersMotion balance equation:21362133142014192836283228282826基i48154518481535282835451828353528倍i2022-8-4河南科技大学机电工程学院382.2 Lathes and lathe cuttersApplication:To cut metric system threadTransmission rou

38、te:ToolrestscrewleadengagingMuuhandlefthandrightSpindle()(53625253636257510010063)(33252533)(33335858基倍2022-8-4河南科技大学机电工程学院392.2 Lathes and lathe cuttersMotion balance equation:)(122536362536257510010063333358581mmuuL倍基倍基uuL7u基,u倍drive ratio of basic shifting group and doubled shifting group.If u基,u

39、倍 are chosen properly,all lead values(112mm)in metric system can be obtained75.628261基u7728282基u7828323基u7928364基u75.914195基u71014206基u71121337基u71221368基u Except for u基1 and u基5,when other drive ratios are expressed by fraction,numerators are arranged in term of arithmetic progression.2.2 Lathes an

40、d lathe cuttersBasic shifting group Double shifting group consists of 3-shaft sliding gear mechanisms among。Four drive ratios can be obtained by shifting the sliding gears:It can be seen that the ratio among them is 2.Its function is to increase or decrease the drive ratio of basic shifting group do

41、ubly so as to cut threads with different pitches.32 kinds of leads can be got by changing u基 and u倍,where there are 20 kinds of standard leads(米制螺纹表米制螺纹表）.81481545181倍u41481535282倍u21283545183倍u1283535284倍u2.2 Lathes and lathe cutters-1.753.571248-2.254.59-1.252.5510-5.5111.5361275.628261基u814815451

42、81倍u41481535282倍u1283535284倍u7728282基u7928364基u75.914195基u71014206基u71121337基u71221368基u7828323基uu基u倍导程L 21283545183倍uTable 2-1 CA6140车床米制螺纹表车床米制螺纹表2022-8-4河南科技大学机电工程学院432.2 Lathes and lathe cutters It can be seen from Tab.2-1 that CA6140 lathe has the ability to cut the metric system threads whose

43、maximum lead is only 12 mm.When the leads larger than 12 mm are required to cut on this lathe,the lead-enlarging transmission mechanism must be used.Here the sliding gear Z58 on shaft should be shifted to the right(the position of dashed line shown in Fig.2-11)to engage with the gear Z26 on shaft.An

44、d then the connection between shaft and shaft is realized by means of a train of gears via shaft,and,instead of the gear drive pairs 58/58.2022-8-4河南科技大学机电工程学院442.2 Lathes and lathe cuttersLead-enlarging transmission route）（接正常导程传动路线（正常导程）（扩大导程）主轴5858582644442080505020802658 It can be seen from lead

45、-enlarging transmission route that the drive ratio from spindle to shaft ：When spindle revolution is 40-125r/min,4582644445050208026581扩uWhen spindle revolution is 10-32r/min,16582644442080208026582扩u2022-8-4河南科技大学机电工程学院452.2 Lathes and lathe cutters2)Power feed transmission chains They are used pri

46、marily for cylindrical turning and facing.In order to reduce the wear of lead screw and ensure transmission accuracy of thread turning,power feed is driven by means of rod instead of lead screw.spindletool rest1r workf tool(mm)Lathe CA6140 has 64 kinds of longitudinal feeds and transverse feeds,wher

47、e normal feeds:32;large feeds:8;larger feeds:16;fine feeds:8.Normal feeds：From spindle via normal pitch and metric thread transmission route to toolrest横向丝杠纵向齿轮、齿条光杠主轴倍基1859484848303040484080284840483030402945632323656282536362536257510010063332525333333585877668MMMMMii213621331420141928362832282828

48、26基i48154518481535282835451828353528倍i2.2 Lathes and lathe cutters2022-8-4河南科技大学机电工程学院472.2 Lathes and lathe cuttersNormal feeds：)/(125.28028483030402945632323656282536362536257510010063333358581rmmiif 倍基纵倍基纵iif71.0)r/mm(22.1171271.0f)r/mm(08.08175.671.0fmaxmin纵纵横向丝杠纵向齿轮、齿条光杠主轴倍基18594848483030404840

49、80284840483030402945632323656282536362536257510010063332525333333585877668MMMMMii2022-8-4河南科技大学机电工程学院482.2 Lathes and lathe cuttersNormal feeds：)/(51859484848402945632323656282536362536257510010063333358581rmmiif倍基横倍基横iif355.0)/(61.01712355.0)/(04.08175.6355.0maxminrmmfrmmf横横横向丝杠纵向齿轮、齿条光杠主轴倍基1859484

50、848303040484080284840483030402945632323656282536362536257510010063332525333333585877668MMMMMii2022-8-4河南科技大学机电工程学院492.2 Lathes and lathe cuttersLarge feeds：From spindle via normal pitch and inch thread transmission route to toolrest)/(125.2802848303040294563232365628253617510010063333358581rmmiif 倍基