【正文】 1 畢 業(yè) 論 文 （科 學(xué) 研 究 報 告） 題 目 汽車發(fā)動機四缸曲軸加工工藝 及夾具設(shè)計 院 (系 )別 機電及自動化學(xué)院 專 業(yè) 機械工程及自動化 級 別 2021 學(xué) 號 ***** 姓 名 *** 指導(dǎo)老師 *** 副 教授 ** 大 學(xué) 教 務(wù) 處 2021 年 6 月 I 摘 要 曲軸是汽車發(fā)動機的重要零件。它的作用是把活塞的往復(fù)直線運動變成傳動軸的旋轉(zhuǎn)運動，將作用在活塞的氣體壓力變成扭矩，用來驅(qū)動工作 機械和發(fā)動機各輔助系統(tǒng)進行工作。曲軸在工作時承受著不斷變化的壓力、慣性力和它們的力矩作用，因此要求曲軸具有強度高、剛度大、耐磨性好，軸頸表面加工的尺寸精確，且潤滑可靠。 本設(shè)計是根據(jù)被加工曲軸的技術(shù)要求 ，進行機械工藝規(guī)程的設(shè)計，然后運用夾具設(shè)計基本原理和方法，擬定夾具設(shè)計方案，完成夾具結(jié)構(gòu)設(shè)計。主要工作有：繪制產(chǎn)品零件圖，了解零件結(jié)構(gòu)特點和技術(shù)要求；根據(jù)生產(chǎn)類型和所在企業(yè)生產(chǎn)條件，對零件進行結(jié)構(gòu)分析及工藝分析；確定毛坯種類及制造方法；擬定零件機械加工工藝過程，選擇各工序的加工設(shè)備與工藝設(shè)備，確定各工序的加工 余量與工序尺寸，計算各工序的切削用量與工時定額；填寫機械加工工藝過程卡片、機械加工工序卡片等工藝卡片；設(shè)計指定的專用夾具，繪制裝配總圖和主要零件圖。 本次設(shè)計主要是為了提高曲軸零件的生產(chǎn)效率，以及加工精度。因此，制定工藝路線時嚴格按照 基準先行，先主后次，先粗后精，先面后孔 的工藝設(shè)計準則。先加工出基準，再用精基準定位加工其它工序。在夾具設(shè)計時，選擇的是車曲軸連桿軸頸的工序，定位時選擇兩個 V形塊和周向定位釘定位，用壓板夾緊，并且在夾具上設(shè)置合適的偏心距。 通過本次設(shè)計我查閱了許多書籍和行業(yè)資料，了解到行業(yè)的發(fā)展 進程和部分先進技術(shù)，擴展了我的專業(yè)視野，為將來的學(xué)習(xí)生活都有著重要的影響。 關(guān)鍵詞 ： 機械制造，加工工藝，曲軸，夾具 II ABSTRACT Crankshaft is a very important parts of diesel engine. Ist action is change the to and fro straightline motion of the piston into rotary motion,and change the gas pressure on the piston into torque, that is used to drive executive body and accessory system of the diesel engine. Crankshaft is withstanding the changing pressure, inertia force and the torque. So the crankshaft mast have high strength, high rigidity, high abrasion resistance and the surface of axle journal must have high precision with well lubricating. This design is on the basis of technical requirement of the crankshaft to design the technological procedure. And then use the fundamental and method of the fixture design to fix the fixture design programme,and plete the structural of the fixture. The main work is: Parts drawing, understand the characteristic of structure and technical requirement。 Accroding to the types of manufacturing and the plant conditions of the pany we will analyse the structure and craft of the crankshaft。 Fix the type and manufacturing method of the roughcast。 Fix the processing technic of the crankshft,select device and equipment fix the machining allowance and working procedure size and count the cutting specifications and time allowance.。 Fix the Processing technological process card and Machinefinishing operation card。 Design the special fixture and plan the assembling drawing and main parts drawing. This design is in order to improve the crankshaft parts production efficiency, and the machining accuracy. Therefore,when drawing up the process we strict accordance with the design criteria that benchmark first,main first then secondary, rough first then essence, surface first ， hole after . First, work out benchmark, again with pure reference positioning processing other processes. In fixture design,I choose the car process of crankshaft connecting rod , When location,I choose two V block and circumferential locating pin to positioning, pressed powder pact, and set up appropriate eccentricity on the jig. Accroding to this design I looked through many books and industry information, understand some of the industry development process and advanced technologies,and also expanded my professional has important influence on my future study and life. KEYWORDS: Machine manufacture Processing craft Crankshaft fixture 1 目 錄 摘 要 ....................................................... I ABSTRACT .................................................... II 第一章 緒 論 ................................................ 3 設(shè)計的主要內(nèi)容 .................................................... 3 國內(nèi)外的研究現(xiàn)狀 .................................................. 3 第二章 零件分析 .............................................. 7 零件的作用 ........................................................ 7 曲軸工藝分析 ...................................................... 7 第三章 工藝規(guī)程設(shè)計 .......................................... 8 確定毛坯的材料和制造形式 .......................................... 8 基面的選擇 ........................................................ 8 粗基準的選擇 ........................................................................................................ 8 精基準的選擇 ........................................................................................................ 8 制定工藝路線 ...................................................... 8 工藝路線方案 ...................................................... 9 機械加工余量、工序尺寸及毛坯尺寸的確定 ........................... 10 確定加工余量 ...................................................................................................... 10 確定工序尺寸及其公差 .........................................................................................11 加工余量計算 .......................................................................................................11 確定主要工序的切削用量及基本工時 ................................. 16 第四章 專用夾具設(shè)計 ......................................... 37 設(shè)計主旨 ......................................................... 37 需要解決的主要問題 ............................................... 37 形狀復(fù)雜 ............................................................................................................. 37 剛性差 ................................................................................................................ 37 技術(shù)要求高 ......................................................................................................... 37 確定夾具設(shè)計方案 ................................................. 38 選擇定位基準，并確定工件的定位方式及定位元件的結(jié)構(gòu) ................................... 38 確定工件的夾緊方式，選擇合適的夾緊機構(gòu) ........................................................ 38 確定銑床夾具與機床間的正確位置 ...................................................................... 39 夾緊力的計算 ..................................................... 39 切削力的計算 ...................................................................................................... 39