【正文】
to enjoy that cover integral along the slip line the average stress putation formula is as follows: (3) (4)Type: ——the average stress, Mpa——shear yield stress, Mpa——for a and line is constant (the same group of different slip line its value is different).If a gens slip line of a certain point the average stress, so in the online known any average stress can then find out. As shown in figure 4 shows, slip line of a known the average stress and Angle, also know from the point of view of the known size, can be calculated the stress. Its putation formula is: (5)The two points on the c, d solution and (5) type similar namely: With differential form: (along) (7) (along) (8)The above formula shows that the average slip line along with the change of stress and the size of the corner is proportional to the relationship, and also proved slip line the larger, the two corner of the two points on average more stress changes, the corresponding value are more big. The above all he can solve gradually. A gens slip line is always the sum of all point stress deformation force.In general, move the blade material to cut off from the start the process was not pure shear so far, but when two blade cut into the distant relative of the 1/3 place central produce slip and when fracture. The above three deformation stage plastic deformation theory and shear force test curve can confirm this, in central sliding zone reinforced shear force fell sharply until fracture.So in the calculation of the shear force should be considered material shear deformation is gradually enlarged and the central produce slip line is mainly posed of shear strength and shear force is caused by the two, ignoring the shear deformation factors is not correct. The pressure of deformation and stress analysisPressure into the deformation is a distant relative role in two blade on the positive pressure, the putation formula is as follows: (9)Type of: ——The contact stress on average,Mpa;——Cut mark bow area.By (9), it is known that the role of the positive pressure in the reinforced produce creasing area, the area, the greater the pressure is the larger, and shear strength curve up sharply. Shear sliding stress analysisTwo blade cut increase shear section depth, arc of acreage more aspects of the blade, lateral force more, lateral torque T and the distant corner of gamma also will increase (material the harder the P2), slip value of shear force press type calculation: (10)式中:——Shear force,N; ——Shear strength and tensile strength than the, ——Cut off the broken area of reinforced, ——Shear strength,Mpa;, Tensile strength,K as blade passivation coefficient,Take 。t below 15%, cut off the force can not have small the three aspects to the prehensive performance evaluation.附錄 2附錄2燕 山 大 學(xué)本科畢業(yè)設(shè)計(jì)(論文)開題報(bào)告課題名稱: 螺紋鋼切斷機(jī) 學(xué)院(系): 年級專業(yè): 07級機(jī)制3班 學(xué)生姓名: 指導(dǎo)教師: 完成日期: 2011/3/28 綜述本課題國內(nèi)外研究動(dòng)態(tài),說明選題的依據(jù)和意義現(xiàn)在,各工業(yè)化國家都把制造技術(shù)視為當(dāng)代科技發(fā)展最為活躍的領(lǐng)域和國際間科技競爭的主戰(zhàn)場,制訂了一系列振興計(jì)劃,建立世界級制造技術(shù)中心,紛紛把先進(jìn)制造技術(shù)列為國家關(guān)鍵技術(shù)和優(yōu)先發(fā)展領(lǐng)域。3. 機(jī)械制造系統(tǒng)的自動(dòng)化、柔性化、集成化及智能化。工藝是生產(chǎn)中最活躍的因素,它既是構(gòu)思和想法,又是實(shí)在的方法和手段,并落實(shí)在由工件、刀具、機(jī)床、夾具所構(gòu)成的工藝系統(tǒng)中,所以它包含和涉及的范圍很廣,需要多門學(xué)科知識的支持,同時(shí)又和生產(chǎn)實(shí)際聯(lián)系十分緊密。2.了解影響加工質(zhì)量的各項(xiàng)因素,學(xué)會(huì)分析研究加工質(zhì)量的方法。4. 掌握軋機(jī)設(shè)計(jì)的基本原理和方法。,擬解決的主要問題 傳動(dòng)比的分配 傳動(dòng)方式的選擇 曲柄滑塊機(jī)構(gòu)的選擇 機(jī)體的設(shè)計(jì) 潤滑方式的選擇 鋼筋切斷過程受力分析 曲柄連桿機(jī)構(gòu)的受力分析 傳動(dòng)零件的設(shè)計(jì)校核 切斷零件的分析選擇、方法及措施 ,了解螺紋鋼切斷機(jī)的工作原理、結(jié)構(gòu)特點(diǎn)以及該課題的國內(nèi)外研究動(dòng)態(tài),明確研究的內(nèi)容和方向;,掌握螺紋鋼切斷機(jī)的結(jié)構(gòu)原理和設(shè)計(jì)要點(diǎn);,初定螺紋鋼切斷機(jī)的各部分的結(jié)構(gòu)參數(shù);,對主要零部件進(jìn)行初步設(shè)計(jì),并繪制草圖; ; ,對各部件結(jié)構(gòu)盡行修正,完成主要零部件CAD設(shè)計(jì)圖紙; ,并準(zhǔn)備畢業(yè)設(shè)計(jì)答辯。作為建筑工程中重要材料的鋼筋需求量猛增,有利的拉動(dòng)了鋼筋切斷機(jī)的市場需求。國外切斷機(jī)偏心軸的偏心距較大,國內(nèi)的都比較小,看似省料,齒輪結(jié)構(gòu)偏小,但給用戶帶來麻煩,不易管理。國外切斷機(jī)的機(jī)架都是鋼板焊接機(jī)構(gòu),零部件加工精度、粗糙度,尤其熱處理工藝過硬,使切斷機(jī)在承受過載荷、疲勞失效、磨損失效等方面都優(yōu)于國產(chǎn)機(jī)器。國內(nèi)一般為2831次,國外高出1520次,最高高出30次,工作效率高。(2)定尺精度準(zhǔn)。(4)全自動(dòng)卸料,以進(jìn)一步提高勞動(dòng)生產(chǎn)率。2.螺紋鋼剪切機(jī)國內(nèi)外對比國外記性一般采用半開式結(jié)構(gòu),齒輪軸承用油脂潤滑,曲軸軸頸,連桿瓦,沖切刀座,轉(zhuǎn)體處用手工加稀油潤滑。國內(nèi)切斷機(jī)外觀質(zhì)量,整機(jī)性能不盡人意。尤其對外觀質(zhì)量更是精益求精,外罩一次性沖壓成型,油漆經(jīng)烤漆噴漆處理,色澤搭配科學(xué)合理。而國內(nèi)一些廠家雖然生產(chǎn)歷史比較長,但沒有一家形成規(guī)模,加之設(shè)備老化,加工過程拼體力,憑經(jīng)驗(yàn),生產(chǎn)工藝幾十年一貫制,所以外觀質(zhì)量粗糙,觀感較差。展望未來,我國鋼筋切斷機(jī)發(fā)展的趨勢,機(jī)型將以臥式為主;機(jī)型結(jié)構(gòu)對4065中型切斷機(jī)來說以半開半閉式為主;65以上大型切斷機(jī)將以全開式為主;傳動(dòng)形式仍以齒輪傳動(dòng)為主;對于大型重型切斷機(jī)傳動(dòng)系統(tǒng)探索采用破碎機(jī)結(jié)構(gòu),刀架一端鉸接固定,一端與曲柄連桿機(jī)構(gòu)連接作擺動(dòng)。另外,各制造廠家將繼續(xù)提高產(chǎn)品的整體性能和外觀質(zhì)量,把讓用戶完全滿意和提高用戶忠誠作為最高的追求目標(biāo)。我國的鋼筋切斷加工也應(yīng)朝著這個(gè)方向發(fā)展。,2010年,我國建筑用鋼材總消費(fèi)量約19000萬噸,占鋼材總消費(fèi)量的53%,其中螺紋鋼筋消費(fèi)量7200萬噸,占建筑用鋼的38%。由于我國還是一個(gè)發(fā)展中國家,與發(fā)達(dá)國家還存在一定的差距,因此大部分鋼筋廠還是依靠手工操作,勞動(dòng)強(qiáng)度達(dá),材料消耗量多,現(xiàn)場運(yùn)輸工作量大。鋼筋切斷機(jī)是鋼筋加工必不可少的設(shè)備之一,它主要用于房屋建筑、橋梁、隧道、電站、大型水利等工程中對鋼筋的訂場切斷。鋼筋切斷機(jī)分為機(jī)械式和液壓式,本課題研究的鋼筋切斷機(jī)作為一種機(jī)械式切斷機(jī)在生產(chǎn)實(shí)踐當(dāng)中有著非常廣泛的應(yīng)用。燕山大學(xué)畢業(yè)設(shè)計(jì)(論文)評審意見表指導(dǎo)教師評語:成績: 指導(dǎo)教師簽字: 年 月 日評閱人評語: 成績: 評閱人簽字: 年 月 日燕山大學(xué)畢業(yè)設(shè)計(jì)(論文)答辯委員會(huì)評語表答辯委員會(huì)評語:總成績: 答辯委員會(huì)成員簽字: 答辯委員會(huì)主席簽字: 年 月 日