【正文】 ⑥ Environmental damage。 ④ Corrosion。 ② Deformation。 ④ Applied with continuous direction reversals。 ② Suddenly applied。畢業(yè)設(shè)計（論文） 48 Strength is a measure of the ability to resist, without fails, forces which cause stresses and strains. The forces may be。 ⑦ Environment effects。 ⑤ Manufacturing。 ③ Materials selection。畢業(yè)設(shè)計（論文） 45 參考資料[1] 《起重機(jī)課程設(shè)計 》 陳道南、盛漢中 冶金工業(yè)出版社 [2] 《起重機(jī)設(shè)計手冊 》 機(jī)械工業(yè)出版社 [3] 《起重運輸機(jī)械 》 陳道南、過玉清、周培德、盛漢中 高等學(xué)校試用教材 2022[4] 《機(jī)械零件手冊 》 周開勤 高等教育出版社 [5] 《起重機(jī)計算實例 》 陳國璋、孫桂林、金永懿、孫學(xué)偉、徐秉業(yè) 中國鐵道出版社 1985[6] 《機(jī)械設(shè)計 》 濮良貴、紀(jì)名剛 高等教育出版社 [7] 《互換性與技術(shù)測量 》 廖念釗等 中國計量出版社 畢業(yè)設(shè)計（論文） 46 Design of machine and machine elementsMachine designMachine design is the art of planning or devising new or improved machines to acplish specific purposes. In general, a machine will consist of a bination of several different mechanical elements properly designed and arranged to work together, as a whole. During the initial planning of a machine, fundamental decisions must be made concerning loading, type of kinematic elements to be used, and correct utilization of the properties of engineering materials. Economic considerations are usually of prime importance when the design of new machinery is undertaken. In general, the lowest overall costs are designed. Consideration should be given not only to the cost of design, manufacture the necessary safety features and be of pleasing external appearance. The objective is to produce a machine which is not only sufficiently rugged to function properly for a reasonable life, but is at the same time cheap enough to be economically feasible. The engineer in charge of the design of a machine should not only have adequate technical training, but must be a man of sound judgment and wide experience, qualities which are usually acquired only after considerable time has been spent in actual professional work.Design of machine elements The principles of design are, of course, universal. The same theory or equations may be applied to a very small part, as in an instrument, or, to a larger but similar part used in a piece of heavy equipment. In no ease, however, should mathematical calculations be looked upon as absolute and final. They are all subject to the accuracy of the various assumptions, which must necessarily be made in engineering work. Sometimes only a portion of the total number of parts in a machine are designed on the basis of analytic calculations. The form and size of the remaining parts are designed on the basis of analytic calculations. On the other hand, if the machine is very expensive, or if weight is a factor, as in airplanes, design 畢業(yè)設(shè)計（論文） 47 putations may then be made for almost all the parts. The purpose of the design calculations is, of course, to attempt to predict the stress or deformation in the part in order that it may sagely carry the loads, which will be imposed on it, and that it may last for the expected life of the machine. All calculations are, of course, dependent on the physical properties of the construction materials as determined by laboratory tests. A rational method of design attempts to take the results of relatively simple and fundamental tests such as tension, pression, torsion, and fatigue and apply them to all the plicated and involved situations encountered in presentday machinery. In addition, it has been amply proved that such details as surface condition, fillets, notches, manufacturing tolerances, and heat treatment have a market effect on the strength and useful life of a machine part. The design and drafting departments must specify pletely all such particulars, must specify pletely all such particulars, and thus exercise the necessary close control over the finished product. As mentioned above, machine design is a vast field of engineering technology. As such, it begins with the conception of an idea and follows through the various phases of design analysis, manufacturing, marketing and consumerism. The following is a list of the major areas of consideration in the general field of machine design: ① Initial design conception。致謝畢業(yè)設(shè)計是我們大學(xué)生活中很重要的一個課題，現(xiàn)在我完成畢業(yè)設(shè)計即將完成學(xué)業(yè)、步入社會，首先要感謝孫振軍老師在畢業(yè)設(shè)計過程中的指導(dǎo)和幫助，感謝各位老師四年來的關(guān)心和教導(dǎo)。從整體結(jié)構(gòu)到各個部件都有了一個全面的認(rèn)識。畢業(yè)設(shè)計（論文） 44 結(jié)論通過此次畢業(yè)設(shè)計，讓我了解到了很多方面東西。 參照以上所述，由于所設(shè)計的參數(shù)級別較大，跨度中等，故 分別驅(qū)動采用分別驅(qū)動的方案。在保證浮動軸有足夠長度的情況下，要盡量減小機(jī)構(gòu)的尺寸。(3) 對于集中傳動的大車運行機(jī)構(gòu)，軸承應(yīng)安裝在橋架走臺的撐桿上方，而不要為安裝軸承而增加桿件，以致增加橋架梁重量并使制造麻煩。在布置大車運行機(jī)構(gòu)時，要注意以下幾個方面：(1) 要安裝在起重機(jī)橋架上，橋架的運行速度很高，而且受載之后會發(fā)生撓曲現(xiàn)象，機(jī)構(gòu)零部件在橋架上的安裝不可能十分準(zhǔn)確畢業(yè)設(shè)計（論文） 43 所以單單從保持機(jī)構(gòu)的運動性能和補(bǔ)償安裝的不準(zhǔn)確性著眼，在靠近電動機(jī)、減速器和車輪的軸，最好采用浮動軸。若采用集中傳動時，對于大跨度（一般是） ，一般采用高速集中傳動方案，而對小跨度（ ）可以采用低速集中傳動方案。大車運行機(jī)構(gòu)傳動方案，一般分為兩類：即：分別傳動和集中傳動。一般的設(shè)計步驟為：(1) 確定橋架結(jié)構(gòu)的型式和大車運行機(jī)構(gòu)的傳動方式(2) 布置橋架的結(jié)構(gòu)尺寸(3) 安排大車運行機(jī)構(gòu)的具體位置和尺寸(4) 綜合考慮二者的關(guān)系和完成各個部分的設(shè)計并且，針對實際的情況，對大車運行機(jī)構(gòu)設(shè)計的基本要求是：(1) 機(jī)構(gòu)要緊湊，重量要輕；(2) 和橋架的配合要合適。校核擠壓應(yīng)力畢業(yè)設(shè)計（論文） 41 平均擠壓應(yīng)力: ][)2/(?????dQ即σ=*10 5/(2*300*100)=因[σ]= σ/4=25/4=，故σ[σ]滿足要求。校核重心截面BB:軸孔d的內(nèi)側(cè)拉應(yīng)力最大，按厚壁筒計算： 3/)(???????dhdQ即:畢業(yè)設(shè)計（論文） 40 )250*.370(*????由于σ/325/3=，因 σ壓 σs/3故該設(shè)計滿足要求。 滿足要求 叉子計算畢業(yè)設(shè)計（論文） 39 校核其水平截面AA: 39。h/D=即: 25/.8 )45sin(0*.*3mkgf????因σ s則σ sσ拉 /,故設(shè)計滿足要求。傾斜截面cc的應(yīng)力計算畢業(yè)設(shè)計（論文） 38 )45sin()2/(??? ???FkDQe其中，Q=*105kgf ,e1=(b1+3b2)/(b1+b2)*h/3,(b1=。由于該機(jī)型的起重量較大，故此采用疊片式雙溝，材料 疊片式雙鉤選用鋼，疊片式雙鉤尺寸為參照[2]表1514。短型吊鉤的上面不能裝平衡滑輪，故其上的滑輪數(shù)目僅為偶數(shù)。長型吊鉤裝置兩滑輪間的距離比短滑輪的吊鉤裝置的要小些，故其卷筒也可以短些。長型吊鉤裝置的構(gòu)造特點是：吊鉤裝置在橫軸上，滑輪裝在單獨的心軸上；而短鉤裝置的特點是：吊鉤橫軸與滑輪心軸合二為一。他要求強(qiáng)度足夠，工作安全可靠，轉(zhuǎn)動靈活，不會發(fā)生突然破壞和鋼絲繩脫槽或卡在罩殼內(nèi)的現(xiàn)象。 d=30 （內(nèi)徑）Mw=sl=*4=螺栓材料為 As 屈服極限為 σs=2400kgf/cm2則需用拉伸應(yīng)力為:[ σ]= σs/n2=2400/=1560kgf/cm2, σ[σ],故滿足要求?？梢杂蒙畈鄣木硗病Ｒ话闱闆r下，多采用標(biāo)準(zhǔn)槽，因此其節(jié)距比深槽的短，所以繩槽圈數(shù)相同時，標(biāo)準(zhǔn)槽的卷筒工作長度比深槽的短。繩之間有一定間隙，工作時不會彼此摩擦，可以延長鋼絲繩的使用壽命。 繩端固定裝置計算 繩索卷筒的表面有光面和螺旋槽的兩種。 選擇軸承因軸承的外座圈固定，內(nèi)座圈與心軸一同旋轉(zhuǎn)，應(yīng)按額定動負(fù)荷來選擇。有：[σ1]=2580/*1/=1002kgf/cm2, 因： σw[σ1] 故設(shè)計滿足要求。對于小型齒