【正文】 氣門(mén)端的總當(dāng)量質(zhì)量即得到氣門(mén)慣性力曲線（實(shí)際慣性力應(yīng)與加速度方向相反）、由氣門(mén)運(yùn)動(dòng)規(guī)律測(cè)試表明，實(shí)際的氣門(mén)慣性力變化如下圖虛線所示的情況，在從正慣性力過(guò)渡到負(fù)慣性力的波動(dòng)最大，最易發(fā)生系統(tǒng)的脫落，彈簧力應(yīng)超過(guò)氣門(mén)系數(shù)振動(dòng)時(shí)的慣性力，并且有一定的余量。在初步選定了和后，在氣門(mén)升程曲線右方作出彈簧曲線方程，并在方程曲線上的C2。 C3 、C0等點(diǎn)引水平線盒垂直線，將水平線上截得的彈簧長(zhǎng)度量到對(duì)應(yīng) 的垂直線上，在慣性力圖上 得到彈簧力曲線，彈簧力至少要比慣性力大30%，在慣性力從正變負(fù)區(qū)域彈簧力的儲(chǔ)備量還應(yīng)更大一些，此時(shí)可對(duì)、作出適當(dāng)?shù)恼{(diào)整，以來(lái)滿足要求。 氣門(mén)彈簧的有關(guān)計(jì)算：已知：凸輪軸的轉(zhuǎn)速轉(zhuǎn)/分，和凸輪軸的角速度，進(jìn)氣門(mén)的最大升程，進(jìn)氣門(mén)喉口直徑，圓弧凸輪線的尺寸： ， 搖臂的尺寸：， 挺柱的升程、速度和加速度曲線圖。彈簧的材料采用彈簧鋼，=35兆帕。（1） 彈簧的最大彈力： 式中 K=——彈簧儲(chǔ)備系數(shù)； =130+ =195 ——換氣到氣門(mén)一邊的氣門(mén)機(jī)構(gòu)總重量 =130g —— 氣門(mén)的質(zhì)量， ==55+20=75g ——?dú)忾T(mén)彈簧的質(zhì)量（外彈簧及內(nèi) 彈簧），按結(jié)構(gòu)要求取: =120* =120g——搖臂質(zhì)量。（2）彈簧最小的彈力： =195**/ =239N（3）彈簧的剛度： C= =195***/ = n/m（4）彈簧變形： 1）預(yù)壓縮變形量： =（）* = 2）總變形量： =+ =（5）內(nèi)、外彈簧之間的負(fù)荷分配： 1）內(nèi)彈簧： =*448 = N 2）外彈簧： （6）內(nèi)外彈簧的剛度： =291*= 根據(jù)以求得的值： （7）彈簧的尺寸： A、彈簧鋼絲直徑 : B、彈簧的平均直徑： C、彈簧的工作圈數(shù)： 式中 G=——鋼絲剪切彈性模量 D、彈簧總?cè)?shù): F、氣門(mén)全開(kāi)時(shí)彈簧的長(zhǎng)度: =*+*= =*+*= G、 氣門(mén)關(guān)閉時(shí)彈簧的長(zhǎng)度： mm H、 自由彈簧的長(zhǎng)度： mm =+= I、 彈簧的最大和最小應(yīng)力： 1）內(nèi)彈簧 =兆帕 =兆帕式中 = 在=19/=， 2）外彈簧 = = 式中 ==28/=。 M、平均應(yīng)力和應(yīng)力幅： 1）內(nèi)彈簧 =（595+318）/2= =（595318）/2= 因?yàn)樵趶椈扇χ袘?yīng)力的補(bǔ)償用系數(shù)來(lái)計(jì)算，而1 則： =*1= 2）外彈簧： =（485+259）/2=372兆帕 =（485259）/2=113兆帕 N、彈簧安全系數(shù)： 1）內(nèi)彈簧： =350/（+*）= 式中 = 2）外彈簧： =350/（113+*372）= O、彈簧共振的計(jì)算： =***=21850 =***=17790 =提高氣門(mén)彈簧疲勞強(qiáng)度的措施： 提高彈簧表面質(zhì)量 材料的疲勞破壞總是由于表面的微觀裂紋在拉應(yīng)力的反復(fù)作用下逐步擴(kuò)展而成，因此對(duì)彈簧的表面質(zhì)量應(yīng)有嚴(yán)格的要求。有的高應(yīng)力彈簧就采用磨光彈簧制造。 避免彈簧表面脫碳 氣門(mén)彈簧在熱處理加熱時(shí)，由于氧化使材料表面產(chǎn)生脫碳現(xiàn)象，從而使材料表層疲勞強(qiáng)度降低。為了避免脫碳，彈簧熱處理加熱時(shí)應(yīng)在鹽浴爐或保護(hù)性氣體爐中進(jìn)行。 進(jìn)行噴丸處理 噴丸處理是提高彈簧疲勞強(qiáng)度的有效措施。噴丸處理是用高速運(yùn)動(dòng)的彈丸噴射彈簧表面，引起彈簧表面冷作硬化，并使其表面產(chǎn)生殘余壓縮應(yīng)力，從而提高疲勞強(qiáng)度。此外它還可以抵消表面脫碳的影響。參 考 文 獻(xiàn)專(zhuān)著：【1】：中國(guó)農(nóng)業(yè)機(jī)械出版社，1984【2】，【3】UTOCAD 2004簡(jiǎn)明教程，科學(xué)出版社。2004【4】：人民交通出版社，2009【5】 李澄，吳天生，：高等教育出版社，2003【6】. 北京：高等教育出版社，1997【7】陳于平，. 北京：高等教育出版社，2005?！?】：機(jī)械工業(yè)出版社，2003【9】華大年，華志宏，：上?？萍技夹g(shù)出版社，1995【10】【12】 致 謝本論文的能夠順利的完成，無(wú)不傾注了導(dǎo)師誨人不倦的關(guān)懷、指導(dǎo)和教誨，他嚴(yán)肅的科學(xué)態(tài)度，嚴(yán)謹(jǐn)?shù)闹螌W(xué)精神，精益求精的工作作風(fēng)，深深地感染和激勵(lì)著我。從課題的選擇到項(xiàng)目的最終完成，譚嘯天老師給我細(xì)心的指導(dǎo)和不懈的支持。在此，我還要感謝在一起共同完成此次論文的同學(xué)，正是由于你們的幫助和支持，我才能克服一個(gè)一個(gè)的困難和疑惑，直至論文順利完成。 最后，謹(jǐn)向所有在校園曾經(jīng)關(guān)心和幫助過(guò)我老師和同學(xué)表示最誠(chéng)摯的謝意！ 附錄：外文翻譯In Wang Zuoliang’s translation practices, he translated many poems, especially the poems written by Robert Burns. His translation of Burn’s “A Red, Red Rose” brought him fame as a verse translator. At the same time, he published about ten papers on the translation of poems. Some argue that poems cannot be translated. Frost stresses that poetry might get lost in translation. According to Wang, verse translation is possible and necessary, for “The poettranslator brings over some exciting work from another culture and in doing so is also writing his own best work, thereby adding something to his culture. In this transmission and exchange, a richer, more colorful world emerges. ”(Wang, 1991:112). Then how can we translate poems? According to Wang’s understanding, the translation of poems is related to three aspects: A poem’s meaning, poetic art and language. （1）A poem’s meaning “Sociocultural differences are formidable enough, but the matter is made much more plex when one realizes that meaning does not consist in the meaning of words only, but also in syntactical structures, speech rhythms, levels of style.” (Wang, 1991:93).（2）Poetic art According to Wang, “Bly’s point about the ‘marvelous translation’ being made possible in the United States only after Whitman, Pound and Williams Carlos Williams posed poetry in speech rhythms shows what may be gained when there is a genuine revolution in poetic art.” (Wang, 1991:93).（3）Language “Sometimes language stays static and sometimes language stays active. When language is active, it is beneficial to translation” “This would require this kind of intimate understanding, on the part of the translator, of its genius, its idiosyncrasies, its past and present, what it can do and what it choose not to do.” (Wang, 1991:94). Wang expresses the difficulties of verse translation. Frost’s ment is sufficient to prove the difficulty a translator has to grapple with. Maybe among literary translations, the translation of poems is the most difficult thing. Poems are the crystallization of wisdom. The difficulties of poetic prehension lie not only in lines, but also in structure, such as cadence, rhyme, metre, rhythm, all these conveying information. One point merits our attention. Wang not only talks about the times’ poetic art, but also the impact language’s activity has produced on translation. In times when the language is active, translation is prospering. The reform of poetic art has improved the translation quality of poems. For example, around May Fourth Movement, Baihua replaced classical style of writing, so the translation achieved earthshaking success. The relation between the state of language and translation is so