【文章內(nèi)容簡(jiǎn)介】 徑中心距齒寬因模數(shù)取標(biāo)準(zhǔn)值時(shí)，齒數(shù)已重新確定并圓整則重合度系數(shù)齒間載荷分配系數(shù)齒向載荷分布系數(shù)載荷系數(shù)齒形系數(shù)應(yīng)力修正系數(shù)彎曲疲勞極限彎曲最小安全系數(shù)彎曲壽命系數(shù)尺寸系數(shù)許用彎曲應(yīng)力驗(yàn)算 　　　　　　外嚙合直齒圓柱齒輪傳動(dòng)計(jì)算結(jié)果(表中) (mm) 名稱(chēng)符號(hào)計(jì)算公式小齒輪大齒輪模數(shù)m4齒數(shù)z變位系數(shù)x嚙合角 分度圓直徑d節(jié)圓直徑中心距a實(shí)際中心距中心距變動(dòng)系數(shù)y齒頂高降低系數(shù)齒頂高齒根高齒頂圓直徑齒根圓直徑齒輪寬度B6零件的選擇1鍵的選擇本設(shè)計(jì)選用的鍵有鍵A2260GB109680,鍵A25100 GB109680,本設(shè)計(jì)選用的軸承有軸承GB29764 7210，軸承GB29764 7214，軸承GB29764 7216。本設(shè)計(jì)選用的螺釘有螺釘GB7085M320,螺釘GB7085M420。花鍵的主要失效形式是工作面被壓潰（靜聯(lián)接）或工作面過(guò)度磨損（動(dòng)聯(lián)接）。因此，靜聯(lián)接按工作面的擠壓應(yīng)力進(jìn)行強(qiáng)度計(jì)算，動(dòng)聯(lián)接按照工作面上的壓力進(jìn)行條件性的強(qiáng)度計(jì)算。動(dòng)聯(lián)接花鍵強(qiáng)度條件： （） （） 查表，則計(jì)算轉(zhuǎn)距為： （）  平鍵校核（以電機(jī)軸上的平鍵為例，鍵A1060）由文獻(xiàn)[1]平鍵聯(lián)接的強(qiáng)度校核公式可知： (64)式中 T —傳遞的轉(zhuǎn)矩，D —軸的直徑，m L —鍵的長(zhǎng)度，mm L=60—許用應(yīng)力，=40則有 =所以 =40MPa，所用平鍵合格。 9. 螺釘校核45號(hào)鋼的 () () () () 因?yàn)?所以強(qiáng)度合格結(jié)論經(jīng)過(guò)三個(gè)月的畢業(yè)設(shè)計(jì)，現(xiàn)在順利完成了畢業(yè)設(shè)計(jì)的全部?jī)?nèi)容。通過(guò)此次畢業(yè)設(shè)計(jì)的訓(xùn)練深刻體會(huì)到工程技術(shù)人員的艱辛，同時(shí)領(lǐng)會(huì)到將理論知識(shí)運(yùn)用到實(shí)踐中，是大學(xué)四年來(lái)知識(shí)的全面升華。通過(guò)前期的查閱，了解擠出機(jī)相關(guān)的知識(shí)，最終篩選出與單螺桿相關(guān)的擠出機(jī)文獻(xiàn)資料。之后在參考相關(guān)文獻(xiàn)和老師的指導(dǎo)下，完成了初步方案的初步設(shè)計(jì)。在確定方案后的設(shè)計(jì)過(guò)程中，盡可能將所設(shè)計(jì)的結(jié)構(gòu)和參數(shù)最優(yōu)化。隨著一次次的改圖和方案的更改，我對(duì)螺旋壓力機(jī)有了越加深刻的認(rèn)識(shí)，最后完成的排氣擠出機(jī)的設(shè)計(jì)可以實(shí)現(xiàn)預(yù)定的目的。在這次設(shè)計(jì)過(guò)程中，我認(rèn)為螺桿的設(shè)計(jì)是重中之重，關(guān)鍵就是螺桿的區(qū)別，通過(guò)對(duì)排氣螺桿的進(jìn)一步改進(jìn)，螺旋壓力機(jī)在技術(shù)方面還會(huì)有更大的發(fā)展，而且對(duì)排氣螺桿的改進(jìn)還可以使整臺(tái)機(jī)器的污染量下降，對(duì)提高環(huán)境質(zhì)量有很大的提高。畢業(yè)設(shè)計(jì)在最大程度上綜合了大學(xué)所學(xué)的知識(shí)?；A(chǔ)課是為專(zhuān)業(yè)知識(shí)的鋪墊，為整個(gè)的理論計(jì)算提供了依據(jù)，是整個(gè)設(shè)計(jì)的基礎(chǔ)。我認(rèn)為畢業(yè)設(shè)計(jì)是將基礎(chǔ)知識(shí)應(yīng)用到專(zhuān)業(yè)知識(shí)，將專(zhuān)業(yè)知識(shí)應(yīng)用到具體工程實(shí)踐的過(guò)程。 結(jié)束語(yǔ)此次畢業(yè)設(shè)計(jì)是繼課程設(shè)計(jì)之后，最重要的一次設(shè)計(jì)。花費(fèi)將近半個(gè)學(xué)期的時(shí)間，終于完成了此次設(shè)計(jì)所要完成的任務(wù)。在此期間，碰到的問(wèn)題不計(jì)其數(shù)，花了大量時(shí)間閱讀外文資料和期刊，還有在網(wǎng)上搜索資料，將設(shè)計(jì)中的問(wèn)題逐漸減小。這次畢業(yè)設(shè)計(jì)對(duì)我們大學(xué)期間所學(xué)的知識(shí)，也是一次徹底的考察。將以前學(xué)的機(jī)械基礎(chǔ)知識(shí)應(yīng)用到我們的畢業(yè)設(shè)計(jì)，再一次鞏固了專(zhuān)業(yè)知識(shí)，鍛煉了我們獨(dú)立思考問(wèn)題，解決問(wèn)題和團(tuán)隊(duì)合作的能力，同時(shí)也使我們基本掌握了設(shè)計(jì)的流程。經(jīng)歷了從查閱資料到設(shè)計(jì)計(jì)算再到結(jié)構(gòu)設(shè)計(jì)和軟件分析，對(duì)于我們學(xué)機(jī)械的是必須要掌握的，尤其是想從事科學(xué)研發(fā)方面的工作的更加重要。還有畢業(yè)設(shè)計(jì)使我們基本熟練掌握了OFFICE辦公軟件，AUTOCAD制圖軟件，等，這些為即將走上工作崗位的我們，提前做好了鋪墊。參考文獻(xiàn) 《材料力學(xué)》 《鍛壓手冊(cè)》 《工程制圖學(xué)與計(jì)算機(jī)繪圖》 《機(jī)構(gòu)學(xué)》 《機(jī)械設(shè)計(jì)》 《機(jī)械設(shè)計(jì)手冊(cè)》 《機(jī)械原理》 《機(jī)械制造技術(shù)》 《計(jì)算機(jī)繪圖技術(shù)》 《理論力學(xué)》1 《螺旋壓力機(jī)》1 《模具制造工藝學(xué)》1 《曲柄壓力機(jī)》1 《生物燃料》15 《壓力加工與現(xiàn)代先進(jìn)加工技術(shù)》10外文翻譯英文原文：Biofuel use and its emission of noxious gases in rural ChinaWang Xiaohua
, Feng ZhenminCollege of Engineering, Nanjing Agricultural University, Nanjing 210031, People’s Republic of ChinaReceived 11 August 2003。 accepted 30 September 2003AbstractThis article discusses biomass resources and its consumption in China’s farming area. In 2000, the annual yield of cropstraw was about 6900 Mt, of which 54% could be used as a source of energy. The reasonable supply of firewood was about 150 Mt. The total consumption of biofuel in China’s rural area was 219 Mtce, among which cropstraw and firewood accounted for 44 and 56%, respectively. The proportion of the available heat from mercial energy over the total available heat consumed in the countryside was , and biofuel consumption decreases % annually. China is at a transition point from a period of nonmercial energy to a period of mercial energy being the main source of energy. This article discusses the e?ect of the discharge of noxious gases caused by the consumption of biofuel.Keywords: Biofuel。 Biomass resource。 Noxious gases。 Rural development。 Rural environment。 China1. IntroductionDuring the course of global economic sustainable development, human beings are confronted with immense pressures in population, resources and the environment. The exploitation and utilization of energy is concerned with several factors: Developing countries are faced with the challenge of economic development, especially in the rural area. The energy problem in the rural area is mon in most developing countries. The core of the problem is how to coordinate development energy, society, economy and the environment. Biofuel has been a source of energy which human beings have used since ancient times. It has played an important role during the historical development of human society, and has accounted for more than 15% of China’s energy consumption in recent years. From the environmental point of view, it is part of the essence that poses the ecosystem and will not cause greenhouse warming [1,2].As a very important part of the national energy system, energy supply and consumption in the rural area has a great influence on the development of the rural society, economy and ecological environment. China is a large developing agricultural country, with its rural area largely populated. These areas used to be scarcely supplied with modities and the consumption of mercial energy per capita was low. Nonmercial energy was the main source of energy consumption, which was mainly local biofuel. The increase in population and the sterility of soil gave prominence to the contradiction between the demand and supply of energy, which led to the overconsumption of the local biomass resources and the direct threat to the environment [3–5].With the rapid development of the rural economy and the improvement of peasants’ living conditions, the energy consumption structure of the rural area is undergoing great changes. The demand for mercial energy is rapidly increasing, especially in some rural areas with good economy and modities which consume the main part of the available energy. This led to the superabundance of the original biomass energy source. The improper disposition of the superabundant biomass polluted the atmosphere, waters, and the ecological environment [6–8].Confronted with the pressures from both economical development in the rural area and environmental pr