【正文】 位的步伐，有利于高等教育和企業(yè)人才需求的銜接。毛坯一般都用鑄件。通過 對這些產(chǎn)品的研發(fā)，我國已建立起了自己的人才培養(yǎng)和軟件控制技術(shù)開發(fā)基地以及高精加工設(shè)備生產(chǎn)基地，從而使我國的國民經(jīng)濟綜合實力和科學技術(shù)水平迅速提高，國防尖端武器的生產(chǎn)、“神州六號”的成功發(fā)射與回收、人們生活用品的質(zhì)量提高，有力地說明了我國機械制造業(yè)的發(fā)展狀況。 我國的機械制造業(yè)經(jīng)過 50 多年，特別是近 20 年的發(fā)展，已形成了品種繁多、門類齊、布局合理的機械制造工業(yè)體系。加強工藝管理、提高工藝水平、是機電產(chǎn)品提高質(zhì)量、降低消耗的根本措施。 在指定工藝規(guī)程時，應(yīng)根據(jù)零件的產(chǎn)量和現(xiàn)有的設(shè)備條件，綜合考慮加工質(zhì)量、生產(chǎn)率和經(jīng)濟性的要求，經(jīng)過反復分析比較，確定最 優(yōu)或最適合的方案。 關(guān)鍵字：變速箱 體 工藝 路線 工序 Abstract II Design of technics processes for the gearbox casing of 75 tractor ABSTRACT Machinery manufacturing is one of the pillar industries which show a nation’s development of technology and society. Both traditional and burgeoning industries can’t be separated from verities of mechanical equipment. This disquisition had just selected such a task— to study the machining craft and the fixture for heavy boring shafting bearing holes of Dongfanghong the state of quality and quantity of objects (such as raw materials, semifinished product, ponent or assembly) changes directly in the process is called craft process, such as blank manufacturing, machining, heat treatment, assembly and so on all is called process. In the aspect of machining craft, part drawing and the technological request were thought over， with the help of some information about the machining craft of parts such as boxes it is arranged to produce the part in eighteen steps which include the information on what means to use， which machine tools, what fixtures, assist tools and measure tools needed in each step. Then selected datum plane for each step, studied out orientation and clamping scheme for each step. in the aspect of fixture designing, I had designed a set of fixture for the heavy boring of the shafting bearing holes. After some analyzing and calculating. Keyword: Gearbox casing, Technics process, Working procedure 75 拖拉機變速箱機械加工工藝規(guī)程設(shè)計 III目 錄 摘 要 .......................................................................................................................................... I ABSTRACT ............................................................................................................................ II ...................................................................................................................................... 1 機械制造行業(yè)的地位和發(fā)展 ..................................................................................... 1 設(shè)計的選題意義 .......................................................................................................... 1 設(shè)計的主要內(nèi)容和目的 ............................................................................................. 2 本章小結(jié) ..................................................................................................................... 2 ............................................................................................................... 3 零件的作用 ................................................................................................................. 3 零件的工藝分析 ......................................................................................................... 3 技術(shù)要求 ...................................................................................................................... 3 計算生產(chǎn)綱領(lǐng) ............................................................................................................. 4 計算生產(chǎn)節(jié)拍 ............................................................................................................. 4 3 毛坯的選擇 ........................................................................................................................ 4 確定毛坯的制造形式 .................................................................................................. 4 毛坯的選擇 .................................................................................................................. 4 毛坯的尺寸和公差 ..................................................................................................... 4 確定機械加工余量 ...................................................................................................... 6 毛坯圖的繪制 ............................................................................................................. 7 .................................................................................................................... 8 工藝路線的安排 ................................................................................................... 8 工件的時效處理 .............................................................................................. 8 安排加工工藝的順序時應(yīng)先面后孔 .............................................................. 8 、粗、精加工階段要分開 ................................................................................ 8 基準的選擇 .............................................................................................................. 8 粗基準的選擇 ................................................................................................... 8 精基準的選擇 .................................................................................................. 9 制定工藝路線 ........................................................................................................ 9 .................................................................................. 11 工序 20：銑四個定位平面 ....................................................................................... 11 75 拖拉機變速箱機械加工工藝規(guī)程設(shè)計 IV 工序 25：銑前后平面 ...............................................................................................12 工序 30： 銑上平面 .................................................................................................15 工序 35：粗鏜孔并鉆孔 ...........................................................................................18 工序 40：精鏜孔 .......................................................................................................22 工序 50：在三個平面上鉆孔 ...................................................................................2