【正文】 動機的缸體周圍和缸蓋中都加工有冷卻水套，并且缸體和缸蓋冷卻水套相通，冷卻水在水套內不斷循環(huán)，帶走部分熱量，對缸體和缸蓋起冷卻作用。 為了能夠使缸體內表面在高溫下正常工作，必須對缸體和缸蓋進行適當?shù)乩鋮s。 (3)隧道式缸體：這種形式的缸體曲軸的主軸承孔為整體式，采用滾動軸承，主軸承孔較大，曲軸從缸體后部裝入。 (2)龍門式缸體：其特點是油底殼安裝平面低于曲軸的旋轉中心。 (1)一般式缸體：其特點是油底殼安裝平面和曲軸旋轉中心在同一高度。在缸體內部鑄有許多加強筋，冷卻水套和潤滑油道等。汽車發(fā)動機的缸體和上曲軸箱常鑄成一體，稱為缸體 —— 曲軸箱。 發(fā)動機缸體是發(fā)動機的基礎零件和骨 架，同時又是發(fā)動機總裝配時的基礎零件。缸體 是 箱體類零件， 缸體的 加工特點對加工精度有 非常大的影響，而加工精度直接 關系到 發(fā)動機的裝配質量， 從 而影響發(fā)動機整機的使用性能和壽命。 2 2 被加工零件分析 被 加工零件所屬部件的應用及產品簡介 題目給出的是 GO 汽油機缸體 ， 發(fā)動機缸體是汽車五 大部件之一。驗證、加深、鞏固和擴大已學過的專業(yè)基礎理論和部分專業(yè)知識，了解和掌握本專業(yè)的實際生產知識，為以后的工作打下基礎。本論文主要 在缸體加工過程進行定位基準選擇、刀具選取、夾具的設計和夾緊力的計算，采用合理的夾緊結構極大提高了發(fā)動機生產效率和加工精度，為我國汽車發(fā)動機制造業(yè)的發(fā)展有一定的借鑒，同時有助于我國發(fā)動機制造業(yè)的自有知識產權的形成。發(fā)動機缸體每道加工工序精度控制對缸體加工質量有著重要的影響，如缸體加工過程中發(fā)生加工變形，直接影響到缸體的加工精度和加工質量，最終影響整個發(fā)動機的使用性能，因此對發(fā)動機缸體的制造研究極為重要。 發(fā)動機缸體屬于箱體類零件，結構復雜，壁薄多孔，加工易變形，因此加工精度要求高。而發(fā)動機缸體是汽車發(fā)動機的基礎零件，通過它把發(fā)動機的曲軸連桿機構和配氣機構以及供油、潤滑、冷卻等機構聯(lián)接成一個整體。汽車發(fā)動機制造是我國汽車工業(yè)發(fā)展的一個重要環(huán)節(jié)，為了提高我國汽車制造能力，相關理論研 究和技術改進亟待開展。 雖然我國在汽車發(fā)動機基礎理論及相關技術研究方面取得較大的進步，但是生產設備基本靠進口，工藝標準依賴國外企業(yè)標準，以合資為主。 目前，我國汽車制造業(yè)以中外合資為主，其核心技術一直掌握在歐美日等國手中，尤其是汽車發(fā)動機的研發(fā)與制造，我國的汽車發(fā)動機生產技術主要來源于 美國、德國、意大利、日本等發(fā)達國家。 關鍵詞 : 發(fā)動機缸體 工藝規(guī)程 專用夾具 Abstract The quality of the engine’s manufacturing influenced the performance of the car, as the engine is the heart of the motor vehicles. The accuracy of the manufacturing of the engine block has an important relationship with the overall performance, because the engine block is the fundamental part in the system of the engine. We have to control the machining accuracy and machining quality. With the development of our economy and rapidly growing demand for cars in China, how to improve the production efficiency and processing quality of auto parts, is crucial to the development of automobile industry. Engine cylinder block is one of the five major parts, and its production efficiency and processing quality are directly related to production efficiency and performance of the car. The traditional method to improve production efficiency and processing quality is trying to shorten the auxiliary time and adopt the way of a rigid line, which is already out of date in the current production. Therefore, how to improve the efficiency of engine cylinder block production and processing quality is an important research, and the WD615 engine used in heavy vehicles, including all kinds of engineering machinery, buses, power generation equipment, ships and other ideal power of engine, its cylinder processing design has greater significance. In this paper, we focus on the first step of the process and made research on the process. The engine block belongs to the block pieces, which is plicated in structure and easy to be deformed. We could adopt crankshaft bore as the positioning datum to ensure the accuracy. As the junction surface has a big area and a high demand of the accuracy and roughness, including high amount of the machining parts and high demand of the machining and the long routine of the processing, we have to adopt Horizontal machining center to improve the machining quality and efficiency. The task of the paper is mainly about the reasonable choice on the machining tools and calculation on the fixtures. Keyword: Engine cylinder Technological procedure Special fixture 目 錄 1 前 言 ............................................................................................................................. 1 2 被加工零件分析 ................................................................................................................ 2 被加工零件所屬部件的應用及產品簡介 ................................................................. 2 被加工零件的技術要求 ............................................................................................. 2 3 工藝規(guī)程設計 ..................................................................................................................... 4 生產綱領及節(jié)拍的確定 ............................................................................................. 4 毛坯的選擇 ................................................................................................................. 4 擬訂工藝過程 ............................................................................................................. 5 各工序切削用量的選擇與計算 ................................................................................. 6 4 設備的選擇 ....................................................................................................................... 13 加工中心的基本概念 ................................................................................................ 13 加工中心的分類 ........................................................................................................ 13 加工中心的工藝特點 ................................................................................................ 13 加工中心需要考慮的問題 ........................................................................................ 13 5 專用夾具設計 ................................................................................................................. 15 專用機床夾具概述 ................................................................................................... 15 定位方案的確定 ....................................................................................................... 16 定位方案分析 ................................................................................................. 16 定位元件的設計 ............................................................................................. 18 定位機構的設計 ............................................................................................. 19 定位誤差計算 ................................................................................................. 19 夾緊機構的設計 ..................................................................................................... 20 夾緊力方向的確定