外文翻译--淬硬齿轮的加工-精品.doc

附录1淬硬齿轮的加工【摘要】用于动力传动的齿轮和齿轮箱，其尺寸要求更小，齿轮传动的噪音更低，从而导致对淬硬齿轮的需求，也给齿轮制造厂家提出了探索齿轮加工新方法的要求.概述 用于动力传动的齿轮和齿轮箱，其尺寸要求更小，齿轮传动的噪音更低，从而导致对淬硬齿轮的需求，也给齿轮制造厂家提出了探索齿轮加工新方法的要求。 齿轮在淬硬热处理过程中，其材料组织及应力的改变，通常会使齿轮产生变形，即齿形、齿向及齿距误差。这此误差将引起齿廓在传动时的不正确啮合，从而加大了载荷，产生齿轮噪音。因此，淬硬齿轮在热处理后，一般应添加一道精加工工序。 淬硬齿轮精加工工艺可分为两类：一类是采用非成形的切削刃，如齿轮磨削加工；另一类则是具有成形的切削刃如淬硬齿轮(HRC4853)滚削加工。 本文将集中讨论用于硬滚齿加工的硬质合金刀具成形切削刃的精加工过程。当今的硬质合金材料、刀具涂层和滚齿机技术的发展，已使淬硬齿轮滚切加工技术有了显著的提高，特别是在加工小于或等于12DP的中小模数齿轮时，可承受硬切削过程中所产生的极大的切削力。 硬质合金滚刀的选取 硬质合金滚刀在材料的品种规格上有很大进展。超细、细、中等或大颗粒的硬质合金现在都有产品。此外，硬质合金滚刀毛坯的成形工艺技术也有了显著提高，如采用热等静压(HIP)工艺，该工艺在高压高温下，增加了硬质合金毛坯的内在结合力，提高了硬质合金的抗弯强度。按照ISO的规定，实体硬质合金材料可按应用场合的不同分为若干类：齿轮切削刀具分为K类和P类，K类硬质合金有更高的耐磨性，P类则有更好的高温红硬性。在K牌号和P牌号硬质合金中，每种牌号硬质合金的颗粒结构是不同的，从中等颗粒到超细颗粒。每种牌号都有其应用场合，这是和颗粒结构相关联的。一般来说，对于软滚削，K类比P类的性能要好，K类硬质合金能得到微米级的颗粒结构(粒度小于0.5m)，而P类则不行。在磨耗方面，K类韧性更好，寿命更长。 滚刀的重新刃磨和翻新 滚刀加工一定数量的工件后，其切削刃变钝，此时必须重新刃磨。刃磨后的滚刀必须保持原有的几何形状；切削刃必须锋利；刀具的金相结构绝不可因磨削过热而受破坏。因而在刃磨硬质合金滚刀时应采用一种油基冷却液，它对氯和硫不起反应。对于刮削滚刀，刃磨后的重新涂层并不象用于实体毛坯硬滚的滚刀那样重要。硬质合金滚刀刃磨后涂层前，建议对其刃口进行预处理。 滚刀的重新刃磨将会除去切削表面的原有涂层，这会减少刀具寿命。刀具是可以重涂的。通常对于TiN涂层，可涂34次；对于TiCN和TiALN涂层而言，由于涂层本身有很大的内应力，所以在切削刃上难以再重新涂层。通过几次涂覆TiN涂层后，会产生高低不均匀的状况，并有分层脱落的倾向，所以原有涂层必须去除。 目前有两种方法可去除刀具涂层：化学退涂和物理退涂。用化学退涂去除硬质合金刀具上的涂层是一种精细工艺，要求操作者有相当的熟练程度。过度的化学退涂不仅将涂层去掉，而且还将溶洗钴结合剂，损坏硬质合金材料的微观结构。切削刃的微观损坏将产生锯齿状表面。此外，在退涂时必须对滚刀轴台、内孔及标志进行保护，以免损坏。而物理去涂，则必须由原刀具制造厂来进行，它涉及到整把滚刀齿形的重新磨削。虽然比化学退涂要贵得多，但得到的是一把新滚刀，质量和寿命都能得到保证。 对滚齿机的要求 为了充分发挥硬质合金和涂层工艺的优点，滚齿机应作相应地改进。目前所有先进的滚齿机都按高速滚齿进行设计，其滚齿机的滚刀转速超过3000r/min，通常为5000r/min，工件主轴转速与滚刀转速相匹配。此外，机床具有很高的动刚度和热刚度。先进滚齿机的一些主要设计特点为：采用复合环氧树脂床身，以改进机床的动态和静态特性；带有恒温装置的高速滚刀主轴箱；高速工件主轴；可采用干、湿二种滚削工艺；带光电传感器的数字驱动系统；直线滚动导轨系统；高速自动上料(23秒)；占地紧凑；按人机工程学设计；维修方便。 采用刮削工艺 无论是机械式的还是CNC的滚齿机都能进行刮削，但条件是机床必须装备有工件到刀具的自动同步传动系统。这可使刮削工艺更为经济，对带有自动上下料系统的机床也很重要。电子非接触系统靠一个模拟量传感器发出脉冲来测量刀具主轴、工件主轴和齿轮的位置。机床CNC控制器对这些脉冲进行处理，然后对工件主轴相对于刀具的位置进行调整，使工件轮齿和滚刀刀齿的相对位置关系正确。 在刮削工艺中用冷却液有很多优点：在刮削过程中，冷却液提供了润滑性；由于刮削产生的不是正常的切屑，温度控制极其重要。刮下的切屑较小较薄，不象正常刀屑那样可带走许多热量，所以刮削时采用冷却液可控制刀具、工件及机床系统的温度；冷却液可将切屑从刀具和工件上冲走；改善了工件表面精糙度；提高了刀具寿命。 在“绿色滚削”工艺中，正确选择齿厚余量是很重要的。推荐选择顺铣滚齿，因为它可得到最厚的切屑，这有助于控制切削过程的动态状况，提高刀具寿命。经验证明，切削速度可以超过200m/min，进给量的选择取决于所要达到的表面光洁度。典型进给范围为0.51.25mm/r。刀具移位(窜刀)的方法也很重要，因为刮削时只有粗加工截面的部分切削刃才经受磨损。相反，在“绿色切削”过程中，刀具的精加工部分承担了主要加工量。这意味着在刮削时窜刀量应更大，如齿轮为1248DP时，每次窜刀量为0.30.4mm。 刮削滚刀的选取 刮削硬质合金滚刀分为两大类：用于10DP或更大模数的滚刀，通常都设计有一个负前角的切削前面，当切削刃接触到淬硬齿面时，减小了对硬质合金材料的冲击；对于较小模数的齿轮，就不需要有负前角。负前角的滚刀的缺点是刃磨困难。滚刀刃磨后外径减小，为了得到正确的负前角就应改变砂轮的偏置量。 当刮削中、大模数齿轮时，其齿顶、外圆直径和齿根部位通常都不被滚削，并要求轮齿到齿根有一个平滑的过渡。为得到沉切和完整的过渡圆弧半径，提高齿根的抗弯强度，用于大模数齿轮的理想刮削滚刀应带有凸缘。 对于小模数齿轮的加工，应采用标准滚刀。采用标准的径向前角硬质合金滚刀加工称为“硬质合金滚刀的再滚切”，而不是“刮削”，后者指的是采用了一个负前角滚刀。 硬滚削的技术要求和硬刮削、或硬质合金滚刀再滚削的技术要求几乎相同，不同之处是采用的窜刀移位的策略不同。在硬滚时，切屑的切除需花费大量能量。该能量最终变为热量。设法把这些热量散发带走至关重要。建议每加工一个工件后，滚刀窜位一个全齿距。当滚刀从头到尾窜位过后，应将滚刀移到离原始位置有一个偏置量的部位。该偏置量取决于滚刀的设计和应用，其目的是为了有助于滚刀的均匀磨损。另一不同之处是所采用的装夹系统。由于极大的切削力，夹具必须安全夹紧工件。加工结果表明，同一斜齿轮用硬质合金滚刀再硬滚时，其齿轮质量很高，齿形接近AGMA10级，齿向和齿距超过AGMA12级；全淬硬毛坯硬滚切加工的斜齿轮，其齿轮精度也非常高，齿形精度可达AGMA10级，齿向和齿距可达到AGMA12级。 结论 已探索出许多经济的方法来加工淬硬齿轮，包括材料的选择、软加工方法、热处理工艺和硬精加工，使淬硬齿轮得到普及，满足了高质量传动装置对淬硬齿轮的要求。 个实体全淬硬工件毛坯进行淬硬滚切加工是一种新的加工工艺。由于有刚性更好的机床和优质的硬质合金刀具材料并加以涂层处理，使淬硬滚切成为一种行之有效的加工方法。从工厂的实际应用结果表明，淬硬齿轮滚切(硬滚)工艺具有广阔的应用前景。英文原文Hard gear processingabstract uses in the power drive gear and the gear box, its size request smaller, the gear drive noise is lower, thus causes to the hard gear demand, also gave the gear manufacturer to propose explored the gear to process the new method the requestOutline Uses in the power drive gear and the gear box, its size request smaller, the gear drive noise is lower, thus causes to the hard gear demand, also gave the gear manufacturer to propose explored the gear to process the new method the request. The gear in the hard heat treatment process, its material organization and the stress change, usually can cause the gear to have the distortion, namely tooth profile, tooth to and tooth pitch error. This this error will cause the tooth profile not correctly to mesh in the transmission time, thus has enlarged the load, will have the gear noise. Therefore, the hard gear after the heat treatment, should increase together the precision work working procedure generally. The hard gear precision work craft may divide into two kinds: A kind is uses non- formed the cutting edge, like the gear rubs truncates the processing; Another kind then is has formed the cutting edge like hard gear (HRC48 53) to roll truncates the processing. This article strongly will discuss will use in hardly rolling the hard alloy tools forming cutting edge precision work process which the tooth will process. The now hard alloy material, the cutting tool coating and the gear-hobbing machine technology development, has caused the hard gear to roll cuts the processing technology to have the remarkable enhancement, specially is smaller than in the processing or was equal to when 12DP center small modulus gear, may withstand the enormous cutting force which in the hard cutting process produces. Hard alloy hob selection The hard alloy hob has the very big progress in the material variety specification. Superfine, is thin, medium or the big pellet hard alloy now all has the product. In addition, the hard alloy hob semifinished materials formed craft technology also had the remarkable enhancement, like uses static pressure and so on heat (HIP) the craft, this craft under the high-pressured high temperature, increased the hard alloy semifinished materials intrinsic binding force, enhanced the hard alloy anti- curved intensity. According to the ISO stipulation, the entity hard alloy material may differently divide into certain kinds according to the application situation: The gear cutting tool divides into K kind and P kind, K kind of hard alloy has a higher resistance to wear, P kind then has the better high temperature red hardness. In the K trademark and in the P trademark hard alloy, each kind of trademark hard alloy granular structure is different, from medium pellet to superfine pellet. Each kind of trademark all has its application situation, this is and the granular structure is connected. Generally speaking, regarding softly rolls truncates, the K analogy P kind of performance is friends with, K kind of hard alloy can obtain a micron level the granular structure (granularity to be smaller than 0.5 mu m), but P kind then is not good. In abrasion aspect, K kind of toughness better, the life is longer. The hob resharpens and renovates After the hob processing certain quantity work piece, its cutting edge failure, this time must resharpen. Sharpens the after hob to have to maintain the original geometry shape; The cutting edge must be sharp; The cutting tool golden phase structure cannot because rub truncates the heat but to destroy. Thus when sharpens the hard alloy hob should use one kind of oil base refrigerant, it does not get up to the chlorine and the sulfur the response. Regarding scrapes the hob, sharpens after the coating not likely to use in hob such which the entity semifinished materials hardly rolls being important again. After the hard alloy hob sharpens in front of the coating, suggested carries on the pretreatment to its cutting edge. The hob rewill sharpen can except the cutting surface original coating, this will be able to reduce the cutting tool life. The cutting tool is may again spread. Usually regarding the TiN coating, may spread 3 4; Says regarding TiCN and the TiALN coating, because coating itself has the very big internal stress, therefore on cutting edge with difficulty again again coating. After several spreading TiN coating, can have the height non-uniformity condition, and influentials the tendency which the level falls off, therefore the original coating must remove. At present has two methods to be possible to remove the cutting tool coating: Chemistry draws back spreads draws back with physics spreads. Draws back with chemistry spreads removes on the hard alloy tools the coating is one kind of fine craft, requests the operator to have the suitable level of expertise. The excessively chemistry draws back spreads not only removes the coating, moreover also will dissolve washes the cobalt cement, the damage hard alloy material microscopic structure. The cutting edge microscopic damage will produce the zigzag surface. In addition, when draws back spreads must to the hob pillow block, in the hole and the sign carries on the protection, in order to avoid damages. But physics spreads, then must carry on by the original cutting tool factory, it involves to puts in order rerubs the hob tooth profile truncates. Although draws back chemistry spreads must be much more expensive than, but obtains is a new hob, the quality and the life all can obtain the guarantee. To gear-hobbing machine request In order to fully displays the hard alloy and the coating craft merit, the gear-hobbing machine should do correspondingly improves. At present all advanced gear-hobbing machines all press high speed roll the tooth to carry on the design, its gear-hobbing machine hob rotational speed surpasses 3000r/Min, usually is 5000r/Min, the work piece main axle rotational speed and the hob rotational speed match. In addition, the engine bed has very high moves the rigidity and the hot rigidity. The advanced gear-hobbing machine some main design characteristics are: Uses the compound epoxy resin lathe bed, by improves the engine bed the tendency and the static characteristic; Has the constant temperature installment the high speed hob headstock; High speed work piece main axle; May use does, the wet two kinds rolls truncates the craft; Belt electro-optical sensor digital actuation system; The straight line rolls the guide rail system; High speed automatic high-quality goods (2 3 seconds); The occupying a land area of is compact; According to man-machine engineering design; Services conveniently. Uses scrapes the craft Regardless of is the mechanical type the CNC gear-hobbing machine all can carry on scrapes, but the condition is the engine bed must equip has the work piece to the cutting tool selsyn train system. This may cause to scrape the craft economically, to has on the automatic yummy treats system the engine bed very to be also important. The electronic non- contact system depends on a simulation quantity sensor to send out the pulse to survey the cutting tool main axle, the work piece main axle and the gear position. The engine bed CNC controller carries on processing to these pulses, then is opposite to the work piece main axle in the cutting tool position carries on the adjustment, causes a work piece turn of tooth and the hob knife tooth relative position relations is correct. In scrapes in the craft to have very many merits with the refrigerant: In scrapes in the process, the refrigerant has provided the lubricating ability; Because scrapes produces is not the normal scrap, the temperature control is extremely important. Blows the scrap small is thin, does not look like normal knife filings such to be possible to carry off many quantity of heats, therefore scrapes time uses the refrigerant to be possible to control the cutting tool, the work piece and the engine bed system temperature; The refrigerant may washes away the scrap from the cutting tool and the work piece; Improved the work piece surface fine roughness; Enhanced the cutting tool life. Rolls in the green truncates in the craft, correctly chooses the tooth thick remainder is very important. The recommendation choice down milling rolls the tooth, because it may obtain the thickest scrap, this is helpful to the control cutting process dynamic condition, enhances the cutting tool life. The experience proved that, the cutting speed may surpass 200m/Min, enters for the quantity choice is decided by the superficially attractive fineness which must achieve. The model enters for the scope is 0.5 1.25mm/R. The cutting tool shifts (flees knife) the method very to be also important, because scrapes time only then the rough machining section partial cutting edges only then undergo the attrition. On the contrary, in the green cutting in the process, the cutting tool precision work has partially undertaken the main process load. This meant when scraping flees the knife quantity to be supposed to be bigger, when like the gear is 12 48DP, each time flees the knife quantity is 0.3 0.4mm. Scrapes the hob the selection Scrapes the hard alloy hob to divide into two big kinds: Uses in 10DP or the bigger modulus hob, usually all designs has a negative rake front the cutting, when the cutting edge contacts to the hard tooth face, reduced to the hard alloy material impact; Regarding the small modulus gear, does not need to have the negative rake. The negative rake hob shortcoming is sharpens the difficulty. After the hob sharpens the outer diameter to reduce, in order to obtain the correct negative rake to be supposed to change the grinding wheel the bias quantity. When scrapes, the big modulus gear, its addendum, the outer annulus diameter and the tooth root spot all are usually not rolled truncates, and has a smooth transition a request turn of tooth to the tooth root. In order to obtain sinks cuts with the integrity transition circular arc radius, enhances the tooth root the anti- curved intensity, uses in the big modulus gear ideal scraping the hob to be supposed to have the flange. Regarding the small modulus gear processing, should use the standard hob. Uses the standard in front of the radial direction the angle hard alloy hob processing to be called the hard alloy hob to roll again cuts, but is not scrapes, latter referred has used a negative rake hob. Hardly rolls the specification which truncates and hardly scrapes the specification which, or the hard alloy hob rolls again truncates nearly same, similarity is uses the strategy which flees the knife to shift to be different. When hardly rolls, the scrap excision must spend the massive energies. This energy finally becomes the quantity of heat. Tries to carry off very important these thermal sending out. After the suggestion processes a work piece every time, the hob flees a position entire tooth pitch. When the hob will flee from beginning to end the position from now on, will be supposed to transfer to the hob to the initial position has a bias quantity the spot. Th