【正文】 設(shè)計(jì)主要涉及的問題是劃分工藝過程的組成、選擇定位基準(zhǔn)、選擇零件表面加工方法、安排加工順序和組合工序等。工序設(shè)計(jì)的主要內(nèi)容是為沒一工序選擇機(jī)床和工藝裝備，確定加工余量、工序尺寸和公差、確定切削用量、工時(shí)定額及工人技術(shù)等級等。最后就是編制所須的工藝卡片。在整個(gè)設(shè)計(jì)過程中遇到了很多的問題，通過各種途徑想方設(shè)法的解決，比如說：叉車變速箱我可以在我實(shí)習(xí)的合力叉車廠現(xiàn)場觀看內(nèi)部構(gòu)造，師傅也現(xiàn)場幫助我們拆分變速箱，幫我更大程度的認(rèn)識變速箱。這次的畢業(yè)設(shè)計(jì)結(jié)束我不但了解到叉車變速箱的工藝，還學(xué)到了變速箱的其他作用以及傳動系的功用。 這次的畢業(yè)設(shè)計(jì)綜合了所學(xué)的專業(yè)知識,對以后工作,特別是工藝規(guī)程和專用夾具的設(shè)計(jì)中起到相當(dāng)大的作用，對我在大學(xué)中所學(xué)的知識進(jìn)行了延伸和提高，使我能力有很大的提高。 致 謝 本文是在李云老師精心指導(dǎo)和大力支持下完成的。李云老師以其嚴(yán)謹(jǐn)求實(shí)的治學(xué)態(tài)度、高度的敬業(yè)精神、兢兢業(yè)業(yè)、孜孜以求的工作作風(fēng)和大膽創(chuàng)新的進(jìn)取精神對我產(chǎn)生重要影響。她淵博的知識、開闊的視野和敏銳的思維給了我深深的啟迪。同時(shí)，在此次畢業(yè)設(shè)計(jì)過程中我也學(xué)到了許多了關(guān)于機(jī)械加工工藝的知識，實(shí)踐能力有了很大的提高。 另外，還要特別感謝合力叉車的技術(shù)人員對我的指導(dǎo)，他們?yōu)橥瓿杀酒撐奶峁┝司薮蟮膸椭?。還要感謝，同學(xué)的無私幫助，使我得以順利完成論文。 最后，再次對關(guān)心、幫助我的老師和同學(xué)表示衷心地感謝！ 參 考 文 獻(xiàn)[1] ：機(jī)械工業(yè)出版社，2007.[2] 濮良貴 ：高等教育出版社，2010.[3] ：北京大學(xué)出版社，2009[4] :機(jī)械工業(yè)出版社,2008[5] :機(jī)械工業(yè)出版社,1993. [6] ,北京:機(jī)械工業(yè)出版社,2011[7] :機(jī)械工業(yè)出版社，1993.[8] 吉東亮. .[9] :西南交通大學(xué)出版社,2005.[10] ：機(jī)械工業(yè)出版社，2007.[11] 肖永清, :化學(xué)工業(yè)出版社,2006.[12] 孫栓柱 尹祖德 .:機(jī)械工業(yè)出版社，2011[13] 楊國平. 工程汽車、: 機(jī)械工業(yè)出版社，2009附錄一 科技文獻(xiàn)及翻譯 Numerical and experimental analysis of quenching process for cam manufacturing Abstract: In order to obtain satisfactory mechanical properties for the cam used in highpower ship diesel engines, a new quenching technology was proposed by designing a twostage quenching process with an alkaline bath as the quenching medium. To demonstrate the effectiveness of the proposed new quenching technology, both numerical analysis and study were performed. The new quenching technology was analyzed using finite element method. The bined effects of the temperature, stress and fields were investigated considering nonlinear material properties. Finally, an experimental study was performed to verify the effectiveness of the proposed new quenching technology. The numerical results show that internal stress is affected by both thermal stress and transformation stress. In addition, the direction of the internal stress is changed several times due to thermal interaction and microstructure evolution during the quenching process. The experimental results show that the proposed new quenching technology significantly improves the mechanical properties and microstructures of the cam. The tensile strength, the impact and the hardness value of the cam by the proposed new quenching technology are improved by %, % % pared with those by the traditional quenching technology. Moreover, the residual stress and cam shape deformation are reduced by % and % respectively for the cam manufactured by the new quenching technology. Key words: quenching process。 cam manufacturing。 finite element method。 numerical。 simulation experimental study1 IntroductionAs an essential part of a highpower ship, a cam must have a working surface with enough hardness, wear resistance, and toughness in order to have a guaranteed lifespan when working under severe conditions, including heavy load, high temperature, and fatigue. To meet the requirements for mechanical properties of the cam, a quenching process is widely used in the manufacturing of cams. However, traditional quenching processes adopted by domestic cam manufacturers cannot provide satisfactory mechanical properties for the cam. This is indicated by spot corrosion, cracks, and rapid erosion on the working surface of the cam within the designed work cycle. Moreover, traditional quenching processes, which generally consist of only one stage of quenching at a specified temperature, have difficulty in accurately analyzing the temperature and stress fields during the quenching process of the cam. In recent years, has been proposed in this subject. Different from the traditional quenching process, the new quenching technology consists of two stages of `quenching, with an alkaline bath as the quenching medium. It is believed that the proposed new quenching technology brings major advantages over the traditional quenching process, including better mechanical properties, better microstructures, and more accurate shape and dim The quenching process is a plicated process in which interaction occurs among cooling rate, temperature variation, phase transformation, an stress?strain state. For various microstructures during the quenching process, the physical properties of materials (including thermal conductivity, heat transfer coefficient, and specific heat at a constant pressure) and mechanical properties (including elastic modulus, plastic modulus, Poisson ratio, and yield strength), change continuously with the temperature variation. Since the process involves high nonlinearity of the cam material, it is very difficult to accurately analyze the temperature and stress fields during the quenching process of the cam. In recent years, a number of numerical investigations have been performed to predict the changes of temperature and stress fields of the cam during the quenching process . The microstructure and stress variations during quenching were analyzed. HOSSAIN et al predicted the residual and thermal stresses that occur during water quenching of solid spherical balls. KANG and IM established a3D elasticplastic model for plaincarbon steel along with phase transformation to improve the accuracy of numerical simulation. KAKHKI et al simulated the continuous cooling and kinetics of phase and predicted the final distribution of microstructures and hardness in low alloy steels using measured heat transfer coefficients of quenching media by an inverse method. ULYSSE and SCHULTZ investigated the effect of various surface treatments on the mechanical response of cylindrical aluminum missiles during warm water quenching. In the review of the dies on analyzing the quenching process, most of studies were solely focused on numerical simulation for onestage liquidquenching. Only a few studies conducted experimental investigations to verify the accuracy of simulation results. Moreover, the geometry of the