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1、南華大學機械工程學院畢業(yè)設計(論文) 引 言 1. 本計算仍然采用千牛頓-厘米-秒制，g取10。其彈性模數(shù)對Q235鋼取E=2.1MPa 2. 本結構對鋼結構采用極限狀態(tài)計算方法。在本計算中，下述狀態(tài)均為極限狀態(tài)。 ①平衡鐵和吊欄摔下。 ②第一次安裝30米，不附著，不拉懶風繩，即獨立高度30米時： A）30年一過的合風下的非工作狀態(tài)。B）B級強風下，超載25%的工作狀況。 ③以后每次按高15米，即最高層附著以上的自由高度為20.5米，總高度105米時的工作和非工作狀態(tài)。 3. 非工作狀態(tài)的風載取10級狂風風壓值的平均數(shù)440N/，并取風振系數(shù)1.5，從而計算風壓取660N/

2、,他已相當于11級暴風風壓的上限值664.2N/；工作狀況取6級強風風壓值119N/和風振系數(shù)2.25，從而計算風壓取268N/，他已相當于10級大風風壓值的上限：267N/。 4. 工作載荷取一只吊欄超載25%對機架產(chǎn)生的彎矩和兩只吊欄同時超載25%對機架產(chǎn)生的壓力（彎矩為0），即最不利的情況計算，這種情形發(fā)生在一只吊欄停止另一只吊欄同時啟動的瞬間。如由一人操作，這種情形將不會發(fā)生。 5. 焊接件全部采用Q235鋼的第一組材料，在極狀態(tài)下，其許用應力值是： ①抗拉，抗壓，抗彎： {}=235N/=235MPa ②角焊縫：壓，彎，剪：{}={}=160N/=160MPa 6. 對于

3、Q235鋼，在非極限狀態(tài)下，許用應力的取值是： {}=140—160MPa，{}=100—120MPa，對角焊縫：{}={}=120MPa 7. 本計算采用偏于安全的計算方法，為多處支撐，只按一處支撐查穩(wěn)定系數(shù)。 8. 個別計算結果，應力值超過許用值，需要做具體分析，有的已經(jīng)采取了加固措施，同時，多種極限狀況，并不一定同時發(fā)生 1. 整體設計 1.1 整體構造 示意圖如圖1.1： 圖1.1 由一只主動輪和2只壓緊輪組成牽引機，三根并列的鋼絲繩5首斷系在吊欄3上，經(jīng)頂滑輪6，牽引機和頂滑輪后末端系在平衡鐵4上。一臺機架中共有兩臺牽引機對稱布置。設吊欄自重為，裝上重量為P的

4、貨物后，總重量為，各段鋼絲繩上的拉力依次為，用空吊欄提升重為的平衡鐵時，各段繩上的拉力為。 1.2 求鋼絲繩上各段的拉力 1.2.1 牽引傳動 牽引傳動重畫如圖1.2： 圖1.2 求包角： 主動輪底徑380，外徑396.壓緊輪底徑276，外徑296，初定鋼絲繩直徑11， 則繩中心直徑分別為391和287。 主動輪和從動輪之間的關系： 取含油鋼絲繩對生鐵滑輪的摩擦系數(shù)，則 同理 1.2.2 不同載荷下，鋼絲繩上各段拉力的計算值 設計動載系數(shù)和滑輪效率，則不同載荷下鋼絲繩上各段拉力如下表1.1所示：單位KN 表1.1 工況 拉力

5、 空吊欄下降 額足負荷 超15% 超25% 運行 制動 運行 制動 運行 制動 運行 制動 1 2 3 4 5 6 7 8 P1 4.3 12.3 13.53 13.5 17.85 14.3 18.92 P2 12.55 13.71 13.78 15.15 14.59 16.05 P3 12.81 14.09 14.06 15.46 14.89 16.38 P4 13.07 14.38 14.34 15.78 15.19 16.71 P5 8.84 9.7

6、2 8.84 9.72 8.84 9.72 P6 9.02 9.92 9.02 9.92 9.02 9.92 P7平衡鐵 9.2 10.12 9.20 10.12 9.2 10.12 9.2 10.12 P8 9.39 10.33 P9 9.58 10.54 P10 4.05 4.46 P11 40.13 4.46 P12 4.21 4.54 P13 4.3 4.73 4.3 4.3

7、 4.3 電機功率 4.43 5.58 4.98 5.74 1.3 牽引機計算 1.3.1 傳動效率： 速度 取軸承效率 聯(lián)軸器效率 滑輪效率 減速機效率 總效率 額定負荷時： 超載15%時： 超載25%時： 空吊欄下降時： 上述功率在表1.1最后一欄。 1.3.2 安裝功率： 安裝時拿去吊欄底板，此時連同安裝扒桿自重小于4.3KN 選用Y132S-4電動機：N=5.5Kw n=1440轉(zhuǎn)/分 1.3.3 軸上壓力的計算： 按超載25%并制動時計算，見表1.2。 1.a軸

8、 2.A軸 3.B軸 同上，可計算出表1.1中2、4、6工作狀況下各軸上的壓力如表1.2，不同工況下軸上壓力如下：單位：KN 表1.2 工作狀況 軸上壓力 空吊欄下降 額定負荷 超15% 超25% 運行 制動 運行 制動 運行 制動 運行 制動 1 2 3 4 5 6 7 8 O軸 11.16 12.33 14.21 15.63 15.21 16.77 15.95 144.24 A軸 11.34 12.48 23.37 25.71 25.65 33.21

9、 27.17 29.89 B軸 18.99 20.89 15.08 16.61 15.33 16.83 16.09 17.70 2. 平衡鐵計算 2.1 平衡鐵上升時強度校核 2.1.1 結構 圖2.1 如圖2.1所示，用5根[8于A、B、C、D、G、N處焊接而成，AC桿、BD桿截面如圖d，CD桿用口666封口，截面如圖b，CD桿正中EF段，領用口8166加固截面如圖c。C、D交角處，上下用6△焊接，兩側(cè)用σ6三角板加固，焊縫截面如圖e。下面用雙橫桿，截面如圖f。領在H、K、U、V處有滑輪導向，在G、M處有安全鉤。 2.1.2 截面特性

10、 1. AC桿和BD桿，截面如圖2.1d 查得[8： 2. CD桿，截面如圖2.1b 對口666，其 形心到X軸的距離： 故 3. EF段，截面如圖2.1c,板上有2-Φ17孔削弱 形心到X軸（圖6形心）的距離： 4. AB桿，截面如圖2.1f 5. C、D角焊縫 2.1.3 求彎矩 1.計算圖如圖2.2a 圖2.2 各桿的線剛度： 各節(jié)點兩邊桿的分配系數(shù)： C點： A點： 2.求固定彎矩 取試驗

11、荷載：，由此 3.分配傳遞并迭加如下表 表2.1 4.合成彎矩圖如圖2.2b所示 5.強度校核 E、F截面： 2.2 平衡鐵摔下時強度校核 2.2.1 正面： （1）.受力圖 按標準規(guī)定，取5倍額定載荷，即，將此載荷平分在兩只安全鉤上：受力圖如圖2.3a所示： 圖2.3 （2）.彎矩圖 彎矩圖如圖2.3b所示 （3）.強度校核 AB桿： 2.2.2 側(cè)面： （1）.受力圖 受力圖如圖2.4a所示： 圖2.4 （2）.彎矩圖 彎矩圖如圖2.4b所示 （3）.強度校核 [8的另向

12、 2.2.3 滾輪軸及軸承校核 受力圖如圖2.5所示： 圖2.5 圖中 軸頸 其中 選用45Cr，經(jīng)熱處理：其，在極限狀態(tài)下 取 軸承為203軸承，其， 遠小于，又壓環(huán)的可能，然而是瞬間作用，平時工作時，其載荷近似于。 2.2.4 安全鉤校核 結構如圖2.6所示： 圖2.6 3. 吊欄計算 3.1 吊欄柜寬試驗方向計算 1.結構示意和受力圖如圖3.1a所示 圖3.1 由[8組成矩形框，在E、F處有滑輪導向，在G處有安全鉤繩吊在上梁正中R處，當超載25%并制動

13、時，由表1，，吊欄自重作用在下梁正中K處，配重均布，，載荷偏位，作用在L處。 2.求E、F處反力 3.各桿的線剛度及分配系數(shù) 各桿均為2根[8，其 4.求固端彎矩 5.分配傳遞并迭加如下表 表3.1 6.彎矩合成如圖3.1b所示 7.強度校核 （1）.R截面 （2）.C角焊縫 如圖3.2所示： 圖3.2 3.2 吊欄框長度方向計算 1.結構示意和受力情況如圖3.3a所示 圖3.3 2.求反力 3.各桿的線剛度及分配系數(shù) CD、C1D1、A1B1桿相

14、同，為[8，豎擺。其 AB桿為[8與[10之組合，如圖3.4 圖3.4 對[8： 對[10： C1A1、D1B1設為[8，側(cè)擺，其 CC1、A1A、DD1、B1B段為[8，側(cè)面用封口，截面如圖3.5所示： 圖3.5 對[8： 對口466： 4.求固端彎矩 5.分配傳遞并

15、迭加如下表： 表3.2 6.合成彎矩圖如圖3.3b所示 7.強度校核 N截面： D截面： C角： T截面： C角焊縫：截面如圖3.6所示 圖3.6 3.3 卸貨時吊欄框長度方向計算 1.受力圖 如圖3.7a所示 圖3.7 卸貨快完成時，最后一塊預制板離開吊欄，二人自重加半塊預制板重作用于邊框L處，此時，吊欄靜止不動，，配重720-478=242kg均布，，此時： 2.求反力 3.計算固端彎矩 4.分配傳遞并迭加如下表 表3.3 5.合成彎矩圖如圖3.7

16、b所示 6.強度校核 N截面： K截面： T截面： C角焊縫：截面如圖3.6所示，其 3.4 摔下時吊欄框長度方向計算 1.受力圖 如圖3.8a所示： 圖3.8 吊欄摔下時，被安全鉤掛住于U、V處，按規(guī)范取，此時，配重均布，。 2求反力 3.計算固端彎矩 4.分配傳遞并迭加如下表： 表3.4 5.合成彎矩圖如圖3.8b所示 6.強度校核 S截面： G截面： B角截面： B角焊縫： 3.5 摔下時吊欄框?qū)挾确较蛐：? 1.受力圖：如圖3.9a所示 圖

17、3.9 吊欄摔下時，被安全鉤掛住于G處，按規(guī)范取，，吊欄自重478kg，其中CD桿重，CA桿重，DB桿自重。 AB桿自重與配重均布，， 2.求反力 3.計算固端彎矩 4.分配傳遞如下表 表3.5 5.合成彎矩圖如圖3.9b所示 6.強度校核 K截面（再和作用點）： E截面（主桿裝滾輪處）： B角焊縫（同圖4.6所示）： K截面計算式中應力超過許用值，但有地板加固， 截面如圖3.10所示： 圖3.10 從而原式變?yōu)椋? 3.6 吊欄底框計算 1.計算載荷的確定 （1）.寬度方向 見圖3.1a所示，載荷偏

18、向右側(cè)24cm可求及， （2）.受力圖 如圖3.11a所示： 圖3.11 （圖中虛線）在吊欄長度方向又偏右20cm，將此視為、的合力，從而可求及： 2.求反力并作彎矩圖 如圖3.11b所示 3.吊欄底框（欄桿）截面計算 吊欄底框由、和組成。截面如圖3.12所示 圖3.12 ： ： ： 軸為參考軸，求形心 4.縱向強度校核 5.底柜寬度方向 （1）.受力圖 記上述式中的也向兩端分配，可得到邊角上的力值為： 如圖3.13所示： 圖3.

19、13 F端：413kg和211kg E端：315kg和161kg 受力圖如圖3.14a所示： 圖3.14 合成彎矩圖如圖3.14b所示 （2）.強度校核 3.7 緊繩器及吊欄頂板強度計算 1.結構 如圖3.15所示 圖3.15 厚頂板焊接在吊欄框頂梁2根[8上，3只套環(huán)座各用一只U型螺栓與頂板連接。由載荷表查得 2.緊繩器強度校核 考慮某一瞬間只有一只緊繩器承受全部拉力。 （1）.M20螺栓受剪 （2）.套環(huán)座樣板孔受擠壓 （3）.套環(huán)座底板（口850）受彎曲 （4）.套環(huán)座樣板與度板用5-2焊接，焊縫受剪切

20、 3.頂板強度校核 4.螺栓M16校核 3.8 滾輪座、滾輪軸強度校核 1.結構如圖3.16a所示 圖3.16 橫斷面如圖3.16b，連接滾輪座的吊欄立柱橫斷面如圖3.16c所示。 2.工作時校核 （1）.受力圖 由圖3.1a： 由圖3.3a： 由圖3.7a： 圖3.1同圖3.3是同時發(fā)生。 （2）.強度校核 （3）.吊欄立柱扭轉(zhuǎn)校核 上式中的對立柱而言是扭矩。 查及。 （4）.滾輪軸校核 （5）.軸承校核 軸承選為204軸承，其、 由， 查得： 故 轉(zhuǎn)

21、速，查得 按使用4年共計運轉(zhuǎn)3000小時，查得： 故＜ 3.吊欄摔下時校核 （1）.受力圖 如圖3.16所示 由圖3.8a有： 由圖3.9a有： （2）.滾輪座校核 （3）.吊欄立柱扭轉(zhuǎn)校核 軸頸 選用45Cr，并經(jīng)熱處理，其，取 故改用45號鋼經(jīng)熱處理，其，則 （4）.螺栓校核 M12螺栓的公稱應力面積 故 3.9 安全鉤校核 結構如圖3.17所示： 圖3.17 見圖3.9a， 鉤子上的拉應力 銷子上的剪應力 焊縫上的拉應力 文獻翻譯 原文： Numerical Control On

22、e 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 more prominent th

23、an 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 machine tools a

24、nd 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 interfaced with

25、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 more uniforml

26、y , 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 more ve

27、rsatile 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 and p

28、rocesses. 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 efficient

29、ly 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

30、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

31、language 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 .

32、Together, 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 instru

33、ctions 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 par

34、t , 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 prog

35、rammed 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 operati

36、ons and 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 conce

37、pt known 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 an

38、d fed to 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 , th

39、e machine 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

40、 numerical 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

41、data management . 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

42、 ways, like 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 des

43、ign analog hardware 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

44、one designed for a particular price/performance/usage group. Many of the largest manufacturers, like Texas Instruments and Motorola, offer both specialised DSP’s for certain fields like motor-control or modems ,and general high-performance SP’s that can erform broad ranges of processing tasks. Devel

45、opment kits an software are also available , and there are companies making software development tools for DSP’s that allows the programmer to implement complex processing algorithms using simple “drag ‘n’ drop” methodologies. DSP’s more or less fall into two categories depending on the underlying

46、architecture-fixed-point 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 fi

47、xed-point processors tend 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 DSP’s behave more like common general-purpose CPU’s ,with register-files. The

48、re are thousands of different DSP’s 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 DSP’s:

49、Texas Instruments, Motorola, AT&T and Analog Devices. Digital-to-analog conversion In 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

50、 an amplifier or similar audio equipment . This digital to analog conversion (DCA) is performed by a circuit with the same name & Different DCA’s provide different performance and quality , as measured by THD (Total harmonic distortion ), number of bits, linearity , speed, filter characteristics and

51、 other things. The TMS320 family DQP of Texas Instruments The TLS320family consists of fixed-point, floating-point, multiprocessor digital signal processors (DSP’s) , and foxed-point DSP controllers. TMS320 DSP have an architecture designed specifically for real-time signal processing . The F/C240

52、 is a number of the’C2000DSP platform , and 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 f

53、amily the right choice for a wide range of processing applications: --- Very flexible instruction set --- Inherent operational flexibility ---High-speed performance ---Innovative parallel architecture ---Cost effectiveness Devices within a generation of the TMS320 family have the same CPU str

54、ucture but different on-chip memory and peripheral configurations. 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 cos

55、ts and save circuit board space. The 16-bit ,fixed-point DSP core 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

56、adaptive control , Kalman filtering , and state control. The C24x 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 centra

57、l processing unit (CPU) allows the digital designer to process algorithms 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 ext

58、ensive development time and provides the same ease of use as traditional 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

59、code compatible with the C5x generation of DSPs from Texas Instruments. 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 indep

60、endently of the CPU . This combination minimizes quantization and truncation 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

61、in a system. The C24xDSP controllers take advantage of an set of peripheral functions that allow Texas Instruments to quickly configure various series members for different price/ performance points or for application optimization. This library of both digital and mixed-signal peripherals includes

62、: ---Timers ---Serial communications ports (SCI,SPI) ---Analog-to-digital converters(ADC) ---Event manager ---System protection, such as low-voltage and watchdog timer The DSP controller peripheral library is continually growing and changing to suit the of tomorrow’s embedded control marketpla

63、ce. The TMS320F/C240 is the first standard device introduced in the ‘24x series of DSP controllers. It sets the standard for a single-chip digital motor controller. The 240 can execute 20 MIPS. Almost all instructions are executed in a simple cycle of 50 ns . This high performance allows real-time

64、execution of very comple8 control algorithms, such as adaptive control and Kalman filters. Very high sampling rates can also be used to minimize loop delays. The 240 has the architectural features necessary for high-speed signal processing and digital control functions, and it has the peripherals n

65、eeded to provide a single-chip solution for motor control applications. The 240 is manufactured using submicron CMOS technology, achieving a log power dissipation rating . Also included are several power-down modes for further power savings. Some applications that benefit from the advanced processi

66、ng power of the 240 include: ---Industrial motor drives ---Power inverters and controllers ---Automotive systems, such as electronic power steering , antilock brakes, and climate control ---Appliance and HVAC blower/ compressor motor controls ---Printers, copiers, and other office products ---Tape drives, magnetic optical drives, and other mass storage products ---Robotic and CNC milling machines To function as a system manager, a DSP must have robust on-chip I/O and other periphe