机械毕业论文升降机设计

1、引 言1. 本计算仍然采用千牛顿-厘米-秒制，g取10。其弹性模数对q235钢取e=2.1mpa2. 本结构对钢结构采用极限状态计算方法。在本计算中，下述状态均为极限状态。平衡铁和吊栏摔下。第一次安装30米，不附着，不拉懒风绳，即独立高度30米时： a）30年一过的合风下的非工作状态。b）b级强风下，超载25%的工作状况。以后每次按高15米，即最高层附着以上的自由高度为20.5米，总高度105米时的工作和非工作状态。3. 非工作状态的风载取10级狂风风压值的平均数440n/，并取风振系数1.5，从而计算风压取660n/,他已相当于11级暴风风压的上限值664.2n/；工作状况取6级强风风压值1

2、19n/和风振系数2.25，从而计算风压取268n/，他已相当于10级大风风压值的上限：267n/。4. 工作载荷取一只吊栏超载25%对机架产生的弯矩和两只吊栏同时超载25%对机架产生的压力（弯矩为0），即最不利的情况计算，这种情形发生在一只吊栏停止另一只吊栏同时启动的瞬间。如由一人操作，这种情形将不会发生。5. 焊接件全部采用q235钢的第一组材料，在极状态下，其许用应力值是：抗拉，抗压，抗弯： =235n/=235mpa角焊缝：压，弯，剪：=160n/=160mpa6. 对于q235钢，在非极限状态下，许用应力的取值是：=140160mpa，=100120mpa，对角焊缝：=120mpa7

3、. 本计算采用偏于安全的计算方法，为多处支撑，只按一处支撑查稳定系数。8. 个别计算结果，应力值超过许用值，需要做具体分析，有的已经采取了加固措施，同时，多种极限状况，并不一定同时发生1. 整体设计1.1 整体构造示意图如图1.1：图1.1由一只主动轮和2只压紧轮组成牵引机，三根并列的钢丝绳5首断系在吊栏3上，经顶滑轮6，牵引机和顶滑轮后末端系在平衡铁4上。一台机架中共有两台牵引机对称布置。设吊栏自重为，装上重量为p的货物后，总重量为，各段钢丝绳上的拉力依次为，用空吊栏提升重为的平衡铁时，各段绳上的拉力为。1.2 求钢丝绳上各段的拉力1.2.1 牵引传动牵引传动重画如图1.2：图1.2求包角：

4、主动轮底径380，外径396.压紧轮底径276，外径296，初定钢丝绳直径11，则绳中心直径分别为391和287。主动轮和从动轮之间的关系：取含油钢丝绳对生铁滑轮的摩擦系数，则同理1.2.2 不同载荷下，钢丝绳上各段拉力的计算值设计动载系数和滑轮效率，则不同载荷下钢丝绳上各段拉力如下表1.1所示：单位kn表1.1工况拉力空吊栏下降额足负荷超15%超25%运行制动运行制动运行制动运行制动12345678p14.312.313.5313.517.8514.318.92p212.5513.7113.7815.1514.5916.05p312.8114.0914.0615.4614.8916.38p4

5、13.0714.3814.3415.7815.1916.71p58.849.728.849.728.849.72p69.029.929.029.929.029.92p7平衡铁9.210.129.2010.129.210.129.210.12p89.3910.33p99.5810.54p104.054.46p1140.134.46p124.214.54p134.34.734.34.34.3电机功率4.435.584.985.741.3 牵引机计算1.3.1 传动效率：速度取轴承效率 联轴器效率滑轮效率 减速机效率总效率额定负荷时：超载15%时：超载25%时：空吊栏下降时：上述功率在表1.1最后一

6、栏。1.3.2 安装功率：安装时拿去吊栏底板，此时连同安装扒杆自重小于4.3kn选用y132s-4电动机：n=5.5kw n=1440转/分1.3.3 轴上压力的计算：按超载25%并制动时计算，见表1.2。1.a轴2.a轴3.b轴同上，可计算出表1.1中2、4、6工作状况下各轴上的压力如表1.2，不同工况下轴上压力如下：单位：kn表1.2 工作状况轴上压力空吊栏下降额定负荷超15%超25%运行制动运行制动运行制动运行制动12345678o轴11.1612.3314.2115.6315.2116.7715.95144.24a轴11.3412.4823.3725.7125.6533.2127.17

7、29.89b轴18.9920.8915.0816.6115.3316.8316.0917.702. 平衡铁计算2.1 平衡铁上升时强度校核2.1.1 结构图2.1如图2.1所示，用5根8于a、b、c、d、g、n处焊接而成，ac杆、bd杆截面如图d，cd杆用口666封口，截面如图b，cd杆正中ef段，领用口8166加固截面如图c。c、d交角处，上下用6焊接，两侧用6三角板加固，焊缝截面如图e。下面用双横杆，截面如图f。领在h、k、u、v处有滑轮导向，在g、m处有安全钩。2.1.2 截面特性1. ac杆和bd杆，截面如图2.1d查得8： 2. cd杆，截面如图2.1b对口666，其 形心到x轴的距

8、离：故 3. ef段，截面如图2.1c,板上有2-17孔削弱形心到x轴（图6形心）的距离：4. ab杆，截面如图2.1f5. c、d角焊缝2.1.3 求弯矩1.计算图如图2.2a图2.2各杆的线刚度： 各节点两边杆的分配系数：c点： a点： 2.求固定弯矩取试验荷载：，由此3.分配传递并迭加如下表表2.14.合成弯矩图如图2.2b所示5.强度校核e、f截面：2.2 平衡铁摔下时强度校核2.2.1 正面：（1）.受力图按标准规定，取5倍额定载荷，即，将此载荷平分在两只安全钩上：受力图如图2.3a所示：图2.3（2）.弯矩图弯矩图如图2.3b所示（3）.强度校核ab杆：2.2.2 侧面：（1）.受

9、力图受力图如图2.4a所示：图2.4（2）.弯矩图弯矩图如图2.4b所示（3）.强度校核8的另向 2.2.3 滚轮轴及轴承校核受力图如图2.5所示：图2.5图中轴颈 其中选用45cr，经热处理：其，在极限状态下取轴承为203轴承，其，远小于，又压环的可能，然而是瞬间作用，平时工作时，其载荷近似于。2.2.4 安全钩校核结构如图2.6所示：图2.63. 吊栏计算3.1 吊栏柜宽试验方向计算1.结构示意和受力图如图3.1a所示图3.1由8组成矩形框，在e、f处有滑轮导向，在g处有安全钩绳吊在上梁正中r处，当超载25%并制动时，由表1，吊栏自重作用在下梁正中k处，配重均布，载荷偏位，作用在l处。2.

10、求e、f处反力3.各杆的线刚度及分配系数各杆均为2根8，其 4.求固端弯矩5.分配传递并迭加如下表表3.16.弯矩合成如图3.1b所示7.强度校核（1）.r截面（2）.c角焊缝如图3.2所示：图3.23.2 吊栏框长度方向计算1.结构示意和受力情况如图3.3a所示图3.3 2.求反力3.各杆的线刚度及分配系数cd、c1d1、a1b1杆相同，为8，竖摆。其 ab杆为8与10之组合，如图3.4图3.4对8： 对10： c1a1、d1b1设为8，侧摆，其 cc1、a1a、dd1、b1b段为8，侧面用封口，截面如图3.5所示：图3.5对8： 对口466： 4.求固端弯矩 5.分配传递并迭加如下表：表3

11、.26.合成弯矩图如图3.3b所示7.强度校核n截面：d截面：c角：t截面：c角焊缝：截面如图3.6所示图3.63.3 卸货时吊栏框长度方向计算1.受力图如图3.7a所示图3.7卸货快完成时，最后一块预制板离开吊栏，二人自重加半块预制板重作用于边框l处，此时，吊栏静止不动，配重720-478=242kg均布，此时：2.求反力3.计算固端弯矩 4.分配传递并迭加如下表表3.35.合成弯矩图如图3.7b所示6.强度校核n截面：k截面：t截面：c角焊缝：截面如图3.6所示，其3.4 摔下时吊栏框长度方向计算1.受力图如图3.8a所示：图3.8吊栏摔下时，被安全钩挂住于u、v处，按规范取，此时，配重均

12、布，。2求反力3.计算固端弯矩 4.分配传递并迭加如下表：待添加的隐藏文字内容3表3.45.合成弯矩图如图3.8b所示6.强度校核s截面：g截面：b角截面：b角焊缝：3.5 摔下时吊栏框宽度方向校核1.受力图：如图3.9a所示图3.9吊栏摔下时，被安全钩挂住于g处，按规范取，吊栏自重478kg，其中cd杆重，ca杆重，db杆自重。ab杆自重与配重均布，2.求反力3.计算固端弯矩 4.分配传递如下表表3.55.合成弯矩图如图3.9b所示6.强度校核k截面（再和作用点）：e截面（主杆装滚轮处）：b角焊缝（同图4.6所示）：k截面计算式中应力超过许用值，但有地板加固，截面如图3.10所示：图3.10

13、从而原式变为：3.6 吊栏底框计算1.计算载荷的确定（1）.宽度方向见图3.1a所示，载荷偏向右侧24cm可求及，（2）.受力图如图3.11a所示：图3.11（图中虚线）在吊栏长度方向又偏右20cm，将此视为、的合力，从而可求及：2.求反力并作弯矩图如图3.11b所示3.吊栏底框（栏杆）截面计算吊栏底框由、和组成。截面如图3.12所示图3.12： ： ： 轴为参考轴，求形心4.纵向强度校核5.底柜宽度方向（1）.受力图记上述式中的也向两端分配，可得到边角上的力值为：如图3.13所示：图3.13f端：413kg和211kge端：315kg和161kg受力图如图3.14a所示：图3.14合成弯矩图

14、如图3.14b所示（2）.强度校核3.7 紧绳器及吊栏顶板强度计算1.结构如图3.15所示图3.15厚顶板焊接在吊栏框顶梁2根8上，3只套环座各用一只u型螺栓与顶板连接。由载荷表查得2.紧绳器强度校核考虑某一瞬间只有一只紧绳器承受全部拉力。（1）.m20螺栓受剪 （2）.套环座样板孔受挤压（3）.套环座底板（口850）受弯曲（4）.套环座样板与度板用5-2焊接，焊缝受剪切3.顶板强度校核4.螺栓m16校核 3.8 滚轮座、滚轮轴强度校核1.结构如图3.16a所示图3.16横断面如图3.16b，连接滚轮座的吊栏立柱横断面如图3.16c所示。2.工作时校核（1）.受力图由图3.1a：由图3.3a：

15、由图3.7a：图3.1同图3.3是同时发生。（2）.强度校核 （3）.吊栏立柱扭转校核上式中的对立柱而言是扭矩。查及。（4）.滚轮轴校核（5）.轴承校核轴承选为204轴承，其、由，查得： 故转速，查得按使用4年共计运转3000小时，查得：故3.吊栏摔下时校核（1）.受力图如图3.16所示由图3.8a有：由图3.9a有：（2）.滚轮座校核（3）.吊栏立柱扭转校核轴颈 选用45cr，并经热处理，其，取故改用45号钢经热处理，其，则（4）.螺栓校核m12螺栓的公称应力面积故3.9 安全钩校核结构如图3.17所示：图3.17见图3.9a， 钩子上的拉应力销子上的剪应力焊缝上的拉应力文献翻译原文：num

16、erical controlone of the most fundamental concepts in the area of advanced manufacturing technologies is numerical control (nc).prior to the advent of nc, all machine tools were manual operated and controlled. among the many limitations associated with manual control machine tools, perhaps none is m

17、ore prominent than the limitation of operator skills. with manual control, the quality of the product is directly related to and limited to the skills of the operator . numerical control represents the first major step away from human control of machine tools.numerical control means the control of m

18、achine tools and other manufacturing systems though the use of prerecorded, written symbolic instructions. rather than operating a machine tool, an nc technician writes a program that issues operational instructions to the machine tool, for a machine tool to be numerically controlled , it must be in

19、terfaced with a device for accepting and decoding the p2ogrammed instructions, known as a reader.numerical control was developed to overcome the limitation of human operator , and it has done so . numerical control machines are more accurate than manually operated machines , they can produce parts m

20、ore uniformly , they are faster, and the long-run tooling costs are lower . the development of nc led to the development of several other innovations in manufacturing technology:1.electrical discharge machining.2.laser cutting.3.electron beam welding.numerical control has also made machine tools mor

21、e versatile than their manually operated predecessors. an nc machine tool can automatically produce a wide variety of par 4s , each involving an assortment of undertake the production of products that would not have been feasible from an economic perspective using manually controlled machine tools a

22、nd processes.like so many advanced technologies , nc was born in the laboratories of the massachusetts institute of technology . the concept of nc was developed in the early 1950s with funding provided by the u.s air force .in its earliest stages , nc machines were able to make straight cuts efficie

23、ntly and effectively.however ,curved paths were a problem because the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. the shorter is the straight lines making up the step ,the smoother is the curve . each line segment in the steps had to b

24、e calculated.this problem led to the development in 1959 of the automatically programmed tools (apt) language for nc that uses statements similar to english language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. the development of the apt la

25、nguage was a major step forward in the further development of nc technology. the original nc system were vastly different from those used punched paper , which was later to replaced by magnetic plastic tape .a tape reader was used to interpret the instructions written on the tape for the machine .to

26、gether, all of this represented giant step forward in the control of machine tools . however ,there were a number of problems with nc at this point in its development.a major problem was the fragility of the punched paper tape medium . it was common for the paper containing the programmed instructio

27、ns to break or tear during a machining process, this problem was exacerbated by the fact that each successive time a part was produced on a machine tool, the paper tape carrying the programmed instructions had to rerun thought the reader . if it was necessary to produce 100 copies of a given part ,

28、it was also necessary to run the paper tape thought the reader 100 separate times . fragile paper tapes simply could not withstand the rigors of shop floor environment and this kind of repeated use.this led to the development of a special magnetic tape . whereas the paper tape carried the programmed

29、 instructions as a series of holes punched in the tape , thethis most mportant of these was that it was difficult or impossible to change the instructions entered on the tape . to make even the most minor adjustments in a program of instructions, it was necessary to interrupt machining operations an

30、d make a new tape. it was also still necessary to run the tape thought the reader as many times as there were parts to be produced . fortunately, computer technology become a reality and soon solved the problems of nc, associated with punched paper and plastic tape.the development of a concept known

31、 as numerical control (dnc) solve the paper and plastic tape problems associated with numerical control by simply eliminating tape as the medium for carrying the programmed instructions . in direct numerical control, machine tools are tied, via a data transmission link, to a host computer and fed to

32、 the machine tool as needed via the data transmission linkage. direct numerical control represented a major step forward over punched tape and plastic tape. however ,it is subject to the same limitation as all technologies that depend on a host computer. when the host computer goes down , the machin

33、e tools also experience down time . this problem led to the development of computer numerical control.the evelopment of the microprocessor allowed for the development of programmable logic controllers (plc) and microcomputers . these two technologies allowed for the development of computer numerical

34、 control (cnc).with cnc , each machine tool has a plc or a microcomputer that serves the same purpose. this allows programs to be input and stored at each individual machine tool. cnc solved the problems associated downtime of the host computer , but it introduced another problem known as data manag

35、ement . the same program might be loaded on ten different microcomputers with no communication among them. this problem is in the process of being solved by local area networks that connectdigital ignal processors.there are numerous situations where analog signals to be processed in many ways, like

36、filtering and spectral analysis , designing analog hardware to perform these functions is possible but has become less and practical, due to increased performance requirements, flexibility needs , and the need to cut down on development/testing time .it is in other words difficult pm design analog h

37、ardware analysis of signals.the act of sampling an signal into thehat are specialised for embedded signal processing operations , and such a processor is called a dsp, which stands for digital signal processor . today there are hundreds of dsp families from as many manufacturers, each one designed f

38、or a particular price/performance/usage group. many of the largest manufacturers, like texas instruments and motorola, offer both specialised dsps for certain fields like motor-control or modems ,and general high-performance sps that can erform broad ranges of processing tasks. development kits an s

39、oftware are also available , and there are companies making software development tools for dsps that allows the programmer to implement complex processing algorithms using simple “drag n drop” methodologies.dsps more or less fall into two categories depending on the underlying architecture-fixed-poi

40、nt and floating-point. the fixed-point devices generally operate on 16-bit words, while the floating-point devices operate on 32-40 bits floating-point words. needless to say , the fixed-point devices are generally cheaper . another important architectural difference is that fixed-point processors t

41、end to have an accumulator architecture, with only one “general purpose” register , making them quite tricky to program and more importantly ,making c-compilers inherently inefficient. floating-point dsps behave more like common general-purpose cpus ,with register-files.there are thousands of differ

42、ent dsps on the market, and it is difficult task finding the most suitable dsp for a project. the best way is probably to set up a constraint and wishlist, and try to compare the processors from the biggest manufacturers against it.the “big four” manufacturers of dsps: texas instruments, motorola, a

43、t&t and analog devices.digital-to-analog conversionin the case of mpeg-audio decoding , digital compressed data is fed into the dsp which performs the decoding , then the decoded samples have to be converted back into the analog domain , and the resulting signal fed an amplifier or similar audio equ

44、ipment . this digital to analog conversion (dca) is performed by a circuit with the same name & different dcas provide different performance and quality , as measured by thd (total harmonic distortion ), number of bits, linearity , speed, filter characteristics and other things.the tms320 family dqp

45、 of texas instrumentsthe tls320family consists of fixed-point, floating-point, multiprocessor digital signal processors (dsps) , and foxed-point dsp controllers. tms320 dsp have an architecture designed specifically for real-time signal processing . the f/c240 is a number of thec2000dsp platform , a

46、nd is optimized for control applications. the c24x series of dsp controllers combines this real-time processing capability with controller peripherals to create an ideal solution for control system applications. the following characteristics make the tms320 family the right choice for a wide range o

47、f processing applications:- very flexible instruction set- inherent operational flexibility -high-speed performance-innovative parallel architecture-cost effectivenessdevices within a generation of the tms320 family have the same cpu structure but different on-chip memory and peripheral configuratio

48、ns. spin-off devices use new combinations of on-chip memory and peripherals to satisfy a wide range of needs in the worldwide electronics market. by integrating memory and peripherals onto a single chip , tms320 devices reduce system costs and save circuit board space.the 16-bit ,fixed-point dsp cor

49、e of the c24x devices provides analog designers a digital solution that does not sacrifice the precision and performance of their system performance can be enhanced through the use of advanced control algorithms for techniques such as adaptive control , kalman filtering , and state control. the c24x

50、 dsp controller offer reliability and programmability . analog control systems, on the other hand ,are hardwired solutions and can experience performance degradation due to aging , component tolerance, and drift.the high-speed central processing unit (cpu) allows the digital designer to process algo

51、rithms in real time rather than approximate results with look-up tables. the instruction set of these dsp controllers, which incorporates both signal processing instructions and general-purpose control functions, coupled with the extensive development time and provides the same ease of use as tradit

52、ional 8-and 16-bit microcontrollers. the instruction set also allows you to retain your software investment when moving from other general-purpose c2xx generation ,source code compatible with the c2x generation , and upwardly source code compatible with the c5x generation of dsps from texas instrume

53、nts.the c24x architecture is also well-suited for processing control signals. it uses a 16-bit word length along with 32-bit registers for storing intermediate results, and has two hardware shifters available to scale numbers independently of the cpu . this combination minimizes quantization and tru

54、ncation errors, and increases p2ocessing power for additional functions. such functions might include a notch filter that could cancel mechanical resonances in a system or an estimation technique that could eliminate state sensors in a system.the c24xdsp controllers take advantage of an set of peripheral functions that allow texas instruments to quickly confi