汽車變速箱箱體加工工藝及夾具設(shè)計(jì),汽車,變速箱,箱體,加工,工藝,夾具,設(shè)計(jì) Gearbox shell machining process design 《Manufacturing Engineering and Technology—Machining》 Mechanical Industry Press In March 2004, version 1 p560—564 （Serope kalpakjian） （Steven R.Schmid） Abstract Gearbox shell is a more complex structure of spare parts box, its high precision, complex process, and the processing quality will affect the overall performance engine, so it has become the engine manufacturer's focus parts one.Machining process planning must guarantee the machining quality of parts, to meet the technical requirements stipulated in drawings, at the same time should also have high productivity and efficiency. Therefore, machining process planning design is an important work, requires designers must have a rich experience in production practice and wide range of mechanical manufacturing technology basic theory knowledge. In the specified procedure, should according to the production of parts and the existing equipment conditions, taking the processing quality into account, productivity and economy requirements, after repeated analysis and comparison, to determine the optimal or the best solution. 1.Technical Characteristics of the gearbox shell The gearbox shell process features are: the structure of complex shape; processing plane, more than holes; uneven wall thickness and stiffness is low; processing of high precision typical of box-type processing part. The main processing of the surface of cylinder block top surface, the main bearing side, cylinder bore, the main and camshaft bearing bore holes and so on, they will directly affect the machining accuracy of the engine assembly precision and performance, mainly rely on precision equipment, industrial fixtures reliability and processing technology to ensure the reasonableness. 2.The gearbox shell process design principles and the basis Design Technology program should be to ensure product quality at the same time, give full consideration to the production cycle, cost and environmental protection; based on the enterprises ability to actively adopt advanced process technology and equipment, and constantly enhance their level of technology. Gearbox shell machining process design should follow the following basic principles: 2.1 The selection of processing equipment The principle of selection adopted the principle of selection adopted the principle of combining rigid-flexible, processing each horizontal machining center is located mainly small operations with vertical machining center, the key process a crank hole, cylinder hole, balancer shaft hole High-speed processing of high-precision horizontal machining center, an upper and lower non-critical processes before and after the four-dimensional high-efficiency rough milling and have a certain adjustment range of special machine processing; 2.2 Concentration process principle Focus on a key process in principle process the body cylinder bore, crankshaft hole, Balance Shaft hole surface finishing and the combination of precision milling cylinder head, using a process focused on a setup program to complete all processing elements in order to ensure product accuracy The key quality processes to meet the cylinder capacity and the relevant technical requirements; 3.The gearbox shell machining process design the main content Gearbox shell complex structure, high precision, arge size, is thin-walled parts, there are a number of high precision plane and holes. Engine block machining process characteristics; mainly flat and the hole processing, processing of flat generally use planing, milling methods such as processing, processing of hole used mainly boring, processing and multi-purpose drilling holes. As the cylinder complex structure. so how to ensure that the mutual position of the surface processing precision is an important issue. 3.1 The selection of blank Gearbox shell on the materials used are generally gray cast iron HT150,HT200,HT250,there is also cast aluminum or steel plate, this engine block using high-strength alloy cast iron. Cylinder in the processing prior to aging treatment in order to eliminate stress and improve the rough casting mechanical properties. Improve the rough accuracy, reduction of machining allowance, is to improve the automated production line system productivity and processing quality of the important measures. As the foreign box-type parts of rough quality and high precision, and its production-line system has been implemented directly on the blank line, not only eliminating the need for blank check device also saves the rough quality problems due to waste of machining time, increase overall efficiency. Therefore, the refinement of rough is to improve the productivity of the most promising way out. For the engine block production line, can be rough in parts on-line pre-milling six face, removing most of the margin, to facilitate direct on-line parts. 3.2 Machining process selection and processing of the benchmark Choose the right processing technology base is directly related to the processing quality can ensure the parts. Generally speaking, process benchmarking can be divided into coarse and fine reference base. 3.2.1 Coarse reference base The baseline for the on-line thick rough ,which is particularly important the choice of benchmark crude, if crude benchmark choice unreasonable, will the uneven distribution of machining allowance, processing and surface offsets, resulting in waste. In the cylinder production line, we have adopted for the coarse side of the base; 3.2.2 Fine reference base Refined the base of this box for the engine block parts, the general use of "side two sales "for a full range of uniform benchmarks, For the longer automated production positioning. In the gearbox shell of the process, we have adopted to the side, bottom and the spindle hole positioning, in the processing center on the process. 3.3 Machining Processing Stages and processes of the arrangements Often a part of many apparent need for processing, of course, the surface machining accuracy are different. Processing of high precision surface, often after repeated processing; As for the processing of the surface of low precision, only need to go through one or two on the list. Thus, when the development process in order to seize the "processing high precision surface, "this conflict, the reasonable arrangement processes and rational division stage of processing. Arrange the order of the principle of process is: after the first coarse refined, the first surface after the hole, the first benchmark other. In the engine block machining, the same should follow this principle. 3.3.1 roughing stage engine block machining process The arrangements for roughing process, to fully carry out rough rough, trim most of the margin in order to ensure production efficiency; 3.3.2 semi-finishing phase of the engine block machining In order to ensure the accuracy of the middle of some important surface processing, and arrange some semi-finishing operations, will be required accuracy and surface roughness of the surface of the middle of some processing to complete, while demanding the surface of semi-finished, to prepare for future finishing; 3.3.3 The finishing stage The finishing stage of requiring high accuracy and surface roughness of the surface processing; 3.3.4 secondary processing Secondary processing such as small surface screw holes, you can finish of the major surface after the one hand, when the workpiece deformation process little impact at the same time also reduced the rejection rate;In addition,if the main surface of a waste,these small the surface will not have to be processed,thus avoiding a waste of man-hours.However,if the processing is very easy for a small surface bumps the main surface,it should be placed on a small surface finish prior to the main surface finishing; 3.3.5 make proper arrangements for secondary processes Make proper arrangements for secondary processes such as product inspection process,in part roughing stage,the key process before and after processing,spare parts all the processing has been completed,should be appropriate arrangements. Stage of processing division,has the following advantages:First,it can take measures to eliminate the rough workpiece after the stress,to ensure accuracy; second,finishing on the back,and will not damage during transport the surface of the workpiece has been processed;again,first roughing the surface defects can be detected early and promptly deal with rough,do not waste working hours.But most small parts,do not sub very thin. 3.4 The gearbox shell surface of the main processing and secondary processes 3.4.1 Plane processing Plane processing at present, the milling of engine blocks is the primary means of planar processing,domestic milling feed rate is generally 300-400mm/min,and foreign 2000-4000mm/min milling feed rate compared to far cry,to be on increasing,therefore,improve the milling feed rate,reduce overhead time is to improve the productivity of the major means of finishing a number of plane engine block when the milling feed rate to reach 2399mm/min,greatly improved efficiency; Top surface of the cylinder milling is a key process in the process,the flatness requirements for 0.02/145mm,the surface roughness of Ra1.6um.Processing in the cylinder,the use of side and spindle bearing bore positioning,top,bottom and middle vagay only aperture while processing used in the processing line outside of the knife device can better meet the engine block machining accuracy; 3.4.2 General holes Machining General holes Machining holes in general are still using the traditional processing of drilling,expansion,boring,reaming,tapping and other craft approach. Issues in the design process of specific programs,use of coated cutting tools,cutting tools and other advanced tools within the cooling,and using a large flow of cooling systems,greatly improving the cutting speed,improved productivity; 3.4.3 Deep hole processing Deep hole processing of the traditional processing method is used to grade twist drill feed,low efficiency of their production,processing and quality is poor.The deep hole in the engine block processing,the use of gun drilling process; 3.4.4 Cleaning Cleaning is divided into wet cleaning and dry cleaning.Machining cylinder automatic production line using a large flow of wet cleaning; 3.4.5 Detection Detect points outside the line detection and line detection of two kinds. Quality inspection in the engine block,according to the actual situation with lines outside the detection,the main use of coordinate measuring machine integrated measurements of the cylinder,each 200 samples 1-5 pieces,each class random one. 變速箱殼體機(jī)械加工工藝設(shè)計(jì) 摘自： 《機(jī)械工程與技術(shù)（機(jī)加工）》（英文版） 機(jī)械工業(yè)出版社 2004年3月第1版 美國 卡卡爾帕基安·施密德 摘要 變速箱殼體是變速器機(jī)零件中結(jié)構(gòu)較為復(fù)雜的箱體零件，其精度要求高，加工工藝復(fù)雜，并且加工加工質(zhì)量的好壞直接影響發(fā)動機(jī)整個機(jī)構(gòu)的性能，因此，它成為各個發(fā)動機(jī)生產(chǎn)廠家所關(guān)注的重點(diǎn)零件之一。機(jī)械加工工藝規(guī)程必須保證零件的加工質(zhì)量，達(dá)到設(shè)計(jì)圖紙規(guī)定的各項(xiàng)技術(shù)要求，同時還應(yīng)該具有較高的生產(chǎn)率和經(jīng)濟(jì)性。因此，機(jī)械加工工藝規(guī)程設(shè)計(jì)是一項(xiàng)重要的工作，要求設(shè)計(jì)者必須具有豐富的生產(chǎn)實(shí)踐經(jīng)驗(yàn)和廣博的機(jī)械制造工藝基礎(chǔ)理論知識。 1. 變速箱殼體的工藝特點(diǎn) 變速箱殼體的工藝特點(diǎn)是：結(jié)構(gòu)、形狀復(fù)雜；加工的平面和孔比較多；壁厚不均，剛度低；加工精度要求高，屬于典型的箱體類加工零件。變速箱的主要加工表面有頂面、孔系、主軸承孔及螺紋孔等，它們的加工精度將直接影響發(fā)動機(jī)的裝配精度和工作性能，主要依靠設(shè)備進(jìn)度、工夾具的可靠性和加工工藝的合理性來保證。 2. 變速箱殼體工藝方案設(shè)計(jì)原則和依據(jù) 設(shè)計(jì)工藝方案應(yīng)在保證產(chǎn)品質(zhì)量的同時，充分考慮生產(chǎn)周期、成本和環(huán)境保護(hù)；根據(jù)本企業(yè)能力，積極采用國內(nèi)外先進(jìn)的工藝技術(shù)和裝備，不斷提高企業(yè)工藝水平。變速箱殼體機(jī)械加工工藝設(shè)計(jì)應(yīng)遵循以下基本原則： 2.1加工設(shè)備選型原則 加工設(shè)備選型采用剛?cè)峤Y(jié)合的原則，加工設(shè)備以臥式加工中心為主，少量采用立式加工中心，關(guān)鍵工序—曲軸孔、缸孔、平衡軸孔加工采用高精度高速臥式加工中心，非關(guān)鍵工序—上下前后四個平面的粗銑采用高效并有一定調(diào)整范圍的專用機(jī)床加工； 2.2 集中工序原則 關(guān)鍵工序—曲軸孔、缸孔、平衡軸孔的精加工缸蓋結(jié)合面的精銑，采用在集中在一道工序一次裝夾完成全部加工內(nèi)容方案，以確保產(chǎn)品精度滿足缸體關(guān)鍵品質(zhì)的工藝性能和有關(guān)技術(shù)要求。 3. 發(fā)動機(jī)缸體機(jī)械加工工藝設(shè)計(jì)的主要內(nèi)容 發(fā)動機(jī)缸體結(jié)構(gòu)復(fù)雜，精度要求高，尺寸較大，是薄壁零件，有若干精度要求較高的平面和孔。發(fā)動機(jī)缸體機(jī)械加工的工藝特點(diǎn)是：主要是平面和孔的加工，加工平面一般采用刨、銑削等方法加工，加工孔主要采用鏜削，加工小孔多用鉆削。由于缸體結(jié)構(gòu)復(fù)雜，因此如何保證各表面的相互位置精度是加工中的一個重要問題。 3.1 毛坯的選擇 變速箱殼體采用的材料一般是灰鑄鐵HT150、HT200、HT250，也有采用鑄鋁或者鋼板的，此發(fā)動機(jī)缸體采用高強(qiáng)度合金鑄鐵。缸體在加工前進(jìn)行時效處理，以消除鑄件內(nèi)應(yīng)力和改善毛坯的力學(xué)性能。 提高毛坯精度，減少加工余量，是提高自動生產(chǎn)線系統(tǒng)生產(chǎn)率及加工質(zhì)量的重要措施。由于國外箱體類零件毛坯質(zhì)量和精度較高，其生產(chǎn)線系統(tǒng)已實(shí)現(xiàn)了毛坯直接上線，既省去了毛坯檢查裝置，也節(jié)省了由于毛坯質(zhì)量問題而浪費(fèi)的加工工時，提高了綜合效益。因此，精化毛坯是提高生產(chǎn)率最有潛力的出路。對于發(fā)動機(jī)缸體生產(chǎn)線，可在零件上線前粗銑六個面，去除大部分余量，便于零件直接上線。 3.2機(jī)械加工工藝基準(zhǔn)的選擇和加工 選擇合理的加工工藝基準(zhǔn)，直接關(guān)系到能否保證零件的加工質(zhì)量。一般來說，工藝基準(zhǔn)可分為粗基準(zhǔn)和精基準(zhǔn)。 3.2.1 粗基準(zhǔn) 粗基準(zhǔn)對于上線的毛坯，其粗基準(zhǔn)的選擇尤為重要，如果粗基準(zhǔn)選擇不合理，會使加工余量分布不均勻，加工面偏移，造成廢品。在缸體生產(chǎn)線中，我們采用側(cè)面作為粗基準(zhǔn)； 3.2.2 精基準(zhǔn) 粗基準(zhǔn)對于發(fā)動機(jī)缸體這種箱體零件來說，一般采用“一面兩銷”為全線的統(tǒng)一基準(zhǔn)。對于較長的自動自動生產(chǎn)線系統(tǒng)，由于定位銷孔在使用過程中的磨損造成定位不準(zhǔn)確。在變數(shù)箱體的加工中，我們采用了以側(cè)面、底面和主軸孔定位，在加工中心上加工。 3.3 機(jī)械加工加工階段的劃分和工序的安排 一個零件往往有許多表面需要加工，當(dāng)然表面的加工精度是不同的。加工精度較高的表面，往往要經(jīng)過多次加工；而對于加工精度低的表面，只要經(jīng)過一兩次就行了。因此，擬定工藝順序時，要抓住“加工精度高的表面”這個矛盾，合理安排工序和合理劃分加工階段。安排工藝順序的原則是：先粗后精，先面后孔，先基準(zhǔn)后其他。在發(fā)動機(jī)缸體的機(jī)械加工中同樣應(yīng)遵循這一原則。 3.3.1 粗加工階段 在發(fā)動機(jī)缸體的機(jī)械加工過程中，安排粗加工工序，對毛坯全面進(jìn)行粗加工，切去大部分余量，以保證生產(chǎn)效率； 3.3.2 半精加工階段 在發(fā)動機(jī)缸體的機(jī)械加工過程中，為了保證一些重要表面的加工精度，安排一些半精加工工序，將精度和表面粗造度要求中等的一些表面加工完成，而對要求高的表面進(jìn)行半精加工，為以后的精加工做準(zhǔn)備； 3.3.3 精加工階段 對精度和表面粗造度要求高的表面進(jìn)行加工； 3.3.4 次要小表面的加工 如螺紋孔，可以在精加工主要表面后進(jìn)行，一方面加工時對工件變形影響不大，同時廢品率也降低；另外，如果主要表面出廢品后，這些小表面就不必再加 工了，從而避免浪費(fèi)工時。但是，如果小表面的加工很容易碰傷主要表面時，就應(yīng)該把小表面加工放在主要表面的精加工之前； 3.3.5 輔助工序也要妥善安排 如檢驗(yàn)工序，在零件粗加工階段之后，關(guān)鍵工序加工前后，零件全部加工完畢后，都要適當(dāng)安排。 對加工階段進(jìn)行劃分，具有以下好處：首先，可以在粗加工后采取措施消除工作內(nèi)應(yīng)力，保證精度；其次，精加工放在最后面，不至于在運(yùn)輸過程中損壞工件已加工表面；再次，先粗加工各面，可以及早發(fā)現(xiàn)毛坯缺陷并及時處理，不會浪費(fèi)工時。不過對于一般小工件就不要分的很細(xì)。 3.4 箱體的主要加工表面和輔助工序 3.4.1 平面加工 目前，銑削是發(fā)動機(jī)缸體平面加工的主要手段，國內(nèi)銑削進(jìn)給量一般為300-400mm/min，與國外銑削進(jìn)給量2000-4000 mm/min相比，相差甚遠(yuǎn)，有待于提高，因此，提高銑削進(jìn)給量，縮短輔助時間，是提高生產(chǎn)效率的主要途徑，發(fā)動機(jī)缸體精加工一些平面時的銑削進(jìn)給量達(dá)到2399mm/min，大大提高了效率； 頂面的銑削是缸體加工中的一個關(guān)鍵工序，其平面度要求為0.02/145mm，表面粗造度為Ra1.6um。在缸體的加工中，采用側(cè)面和主軸軸承孔定位，頂面、底面和中間瓦蓋面同時加工，在加工中采用線外對刀裝置，能較好地滿足發(fā)動機(jī)缸體加工精度要求； 3.4.2 一般孔系的加工 一般孔系的加工仍采用傳統(tǒng)的鉆、擴(kuò)、鏜、鉸、攻絲等工藝方法。課題在設(shè)計(jì)具體的工藝方案時，采用涂層刀具、內(nèi)冷卻刀具等先進(jìn)刀具，采用大流量冷卻系統(tǒng)，大大提高了切削速度，提高了生產(chǎn)率； 3.4.3 深油孔加工 傳統(tǒng)的加工方法是采用麻花鉆進(jìn)行分級進(jìn)給，其生產(chǎn)效率低，加工質(zhì)量差。在發(fā)動機(jī)缸體深油孔的加工中，采用槍鉆工藝； 3.4.4 清洗 清洗分為濕式清洗和干式清洗。缸體機(jī)械加工自動生產(chǎn)線采用大流量濕式清洗； 3.4.5 檢測 檢測分為在線檢測和線外檢測兩種。在發(fā)動機(jī)缸體的質(zhì)量檢測中，根據(jù)實(shí)際情況采用線外檢測，主要采用三坐標(biāo)測量機(jī)對缸體進(jìn)行綜合測量，每200件抽查1-5件，每班抽查一件。