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有关齿轮的相关文献中英文翻译

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有关齿轮的相关文献中英文翻译

齿轮齿轮Gear是依靠齿的啮合传递扭矩的轮状机械零件。齿轮通过与其它齿状机械零件(如另一齿轮、齿条、蜗杆)传动,可实现改变转速与扭矩、改变运动方向和改变运动形式等功能。由于传动效率高、传动比准确、功率范围大等优点,齿轮机构在工业产品中广泛应用,其设计与制造水平直接影响到工业产品的质量。齿轮轮齿相互扣住齿轮会带动另一个齿轮转动来传送动力。将两个齿轮分开,也可以应用链条、履带、皮带来带动两边的齿轮而传送动力。基本介绍.齿轮在传动中的应用很早就出现了。公元前三百多年,古希腊哲学家亚里士多德在机械问题中,就阐述了用青铜或铸铁齿轮传递旋转运动的问题。中国古代发明的指南车中已应用了整套的轮系。不过,古代的齿轮是用木料制造或用金属铸成的,只能传递轴间的回转运动,不能保证传动的平稳性,齿轮的承载能力也很小。据史料记载,远在公元前400200年的中国古代就巳开始使用齿轮,在我国山西出土的青铜齿轮是迄今已发现的最古老齿轮,作为反映古代科学技术成就的指南车就是以齿轮机构为核心的机械装置。17世纪末,人们才开始研究,能正确传递运动的轮齿形状。18世纪,欧洲工业革命以后,齿轮传动的应用日益广泛先是发展摆线齿轮,而后是渐开线齿轮,一直到20世纪初,渐开线齿轮已在应用中占了优势。早在1694年,法国学者PhilippeDeLaHire首先提出渐开线可作为齿形曲线。1733年,法国人M.Camus提出轮齿接触点的公法线必须通过中心连线上的节点。一条辅助瞬心线分别沿大轮和小轮的瞬心线节圆纯滚动时,与辅助瞬心线固联的辅助齿形在大轮和小轮上所包络形成的两齿廓曲线是彼此共轭的,这就是Camus定理。它考虑了两齿面的啮合状态明确建立了现代关于接触点轨迹的概念。1765年,瑞士的L.Euler提出渐开线齿形解析研究的数学基础,阐明了相啮合的一对齿轮,其齿形曲线的曲率半径和曲率中心位置的关系。后来,Savary进一步完成这一方法,成为现在的EuletSavary方程。对渐开线齿形应用作出贡献的是RoteftWUlls,他提出中心距变化时,渐开线齿轮具有角速比不变的优点。1873年,德国工程师Hoppe提出,对不同齿数的齿轮在压力角改变时的渐开线齿形,从而奠定了现代变位齿轮的思想基础。19世纪末,展成切齿法的原理及利用此原理切齿的专用机床与刀具的相继出现,使齿轮加工具军较完备的手段后,渐开线齿形更显示出巨大的优走性。切齿时只要将切齿工具从正常的啮合位置稍加移动,就能用标准刀具在机床上切出相应的变位齿轮。1908年,瑞士MAAG研究了变位方法并制造出展成加工插齿机,后来,英国BSS、美国AGMA、德国DIN相继对齿轮变位提出了多种计算方法。为了提高动力传动齿轮的使用寿命并减小其尺寸,除从材料,热处理及结构等方面改进外,圆弧齿形的齿轮获得了发展。1907年,英国人FrankHumphris最早发表了圆弧齿形。1926年,瑞土人EruestWildhaber取得法面圆弧齿形斜齿轮的专利权。1955年,苏联的M.L.Novikov完成了圆弧齿形齿轮的实用研究并获得列宁勋章。1970年,英国RolhRoyce公司工程师R.M.Studer取得了双圆弧齿轮的美国专利。这种齿轮现已日益为人们所重视,在生产中发挥了显著效益。齿轮是能互相啮合的有齿的机械零件,它在机械传动及整个机械领域中的应用极其广泛。现代齿轮技术已达到齿轮模数O.004~100毫米齿轮直径由1毫米~150米传递功率可达上十万千瓦转速可达几十万转/分最高的圆周速度达300米/秒。随着生产的发展,齿轮运转的平稳性受到重视。1674年丹麦天文学家罗默首次提出用外摆线作齿廓曲线,以得到运转平稳的齿轮。18世纪工业革命时期,齿轮技术得到高速发展,人们对齿轮进行了大量的研究。1733年法国数学家卡米发表了齿廓啮合基本定律1765年瑞士数学家欧拉建议采用渐开线作齿廓曲线。19世纪出现的滚齿机和插齿机,解决了大量生产高精度齿轮的问题。1900年,普福特为滚齿机装上差动装置,能在滚齿机上加工出斜齿轮,从此滚齿机滚切齿轮得到普及,展成法加工齿轮占了压倒优势,渐开线齿轮成为应用最广的齿轮。1899年,拉舍最先实施了变位齿轮的方案。变位齿轮不仅能避免轮齿根切,还可以凑配中心距和提高齿轮的承载能力。1923年美国怀尔德哈伯最先提出圆弧齿廓的齿轮,1955年苏诺维科夫对圆弧齿轮进行了深入的研究,圆弧齿轮遂得以应用于生产。这种齿轮的承载能力和效率都较高,但尚不及渐开线齿轮那样易于制造,还有待进一步改进。结构介绍.一般有轮齿、齿槽、端面、法面、齿顶圆、齿根圆、基圆、分度圆。1轮齿,简称齿,是齿轮上每一个用于啮合的凸起部分,这些凸起部分一般呈辐射状排列,配对齿轮上的轮齿互相接触,可使齿轮持续啮合运转2齿槽,是齿轮上两相邻轮齿之间的空间端面是圆柱齿轮或圆柱蜗杆上,垂直于齿轮或蜗杆轴线的平面3法面,指的是垂直于轮齿齿线的平面4齿顶圆,是指齿顶端所在的圆5齿根圆,是指槽底所在的圆6基圆,形成渐开线的发生线作纯滚动的圆7分度圆,是在端面内计算齿轮几何尺寸的基准圆。齿轮可按齿形、齿轮外形、齿线形状、轮齿所在的表面和制造方法等分类。齿轮的齿形包括齿廓曲线、压力角、齿高和变位。渐开线齿轮比较容易制造,因此现代使用的齿轮中,渐开线齿轮占绝对多数,而摆线齿轮和圆弧齿轮应用较少。在压力角方面,小压力角齿轮的承载能力较小而大压力角齿轮,虽然承载能力较高,但在传递转矩相同的情况下轴承的负荷增大,因此仅用于特殊情况。而齿轮的齿高已标准化,一般均采用标准齿高。变位齿轮的优点较多,已遍及各类机械设备中。另外,齿轮还可按其外形分为圆柱齿轮、锥齿轮、非圆齿轮、齿条、蜗杆蜗轮按齿线形状分为直齿轮、斜齿轮、人字齿轮、曲线齿轮按轮齿所在的表面分为外齿轮、内齿轮按制造方法可分为铸造齿轮、切制齿轮、轧制齿轮、烧结齿轮等。齿轮的制造材料和热处理过程对齿轮的承载能力和尺寸重量有很大的影响。20世纪50年代前,齿轮多用碳钢,60年代改用合金钢,而70年代多用表面硬化钢。按硬度,齿面可区分为软齿面和硬齿面两种。软齿面的齿轮承载能力较低,但制造比较容易,跑合性好,多用于传动尺寸和重量无严格限制,以及小量生产的一般机械中。因为配对的齿轮中,小轮负担较重,因此为使大小齿轮工作寿命大致相等,小轮齿面硬度一般要比大轮的高。硬齿面齿轮的承载能力高,它是在齿轮精切之后,再进行淬火、表面淬火或渗碳淬火处理,以提高硬度。但在热处理中,齿轮不可避免地会产生变形,因此在热处理之后须进行磨削、研磨或精切,以消除因变形产生的误差,提高齿轮的精度。材料构成制造齿轮常用的钢有调质钢、淬火钢、渗碳淬火钢和渗氮钢。铸钢的强度比锻钢稍低,常用于尺寸较大的齿轮灰铸铁的机械性能较差,可用于轻载的开式齿轮传动中球墨铸铁可部分地代替钢制造齿轮塑料齿轮多用于轻载和要求噪声低的地方,与其配对的齿轮一般用导热性好的钢齿轮。未来齿轮正向重载、高速、高精度和高效率等方向发展,并力求尺寸小、重量轻、寿命长和经济可靠。而齿轮理论和制造工艺的发展将是进一步研究轮齿损伤的机理,这是建立可靠的强度计算方法的依据,是提高齿轮承载能力,延长齿轮寿命的理论基础发展以圆弧齿廓为代表的新齿形研究新型的齿轮材料和制造齿轮的新工艺研究齿轮的弹性变形、制造和安装误差以及温度场的分布,进行轮齿修形,以改善齿轮运转的平稳性,并在满载时增大轮齿的接触面积,从而提高齿轮的承载能力。摩擦、润滑理论和润滑技术是齿轮研究中的基础性工作,研究弹性流体动压润滑理论,推广采用合成润滑油和在油中适当地加入极压添加剂,不仅可提高齿面的承载能力,而且也能提高传动效率。1、齿面磨损对于开式齿轮传动或含有不清洁的润滑油的闭式齿轮传动,由于啮合齿面间的相对滑动,使一些较硬的磨粒进入了摩擦表面,从而使齿廓改变,侧隙加大,以至于齿轮过度减薄导致齿断。一般情况下,只有在润滑油中夹杂磨粒时,才会在运行中引起齿面磨粒磨损。2、齿面胶合对于高速重载的齿轮齿轮传动中,因齿面间的摩擦力较大,相对速度大,致使啮合区温度过高,一旦润滑条件不良,齿面间的油膜便会消失,使得两轮齿的金属表面直接接触,从而发生相互粘结。当两齿面继续相对运动时,较硬的齿面将较软的齿面上的部分材料沿滑动方向撕下而形成沟纹。3、疲劳点蚀相互啮合的两轮齿接触时,齿面间的作用力和反作用力使两工作表面上产生接触应力,由于啮合点的位置是变化的,且齿轮做的是周期性的运动,所以接触应力是按脉动循环变化的。齿面长时间在这种交变接触应力作用下,在齿面的刀痕处会出现小的裂纹,随着时间的推移,这种裂纹逐渐在表层横向扩展,裂纹形成环状后,使轮齿的表面产生微小面积的剥落而形成一些疲劳浅坑。4、轮齿折断在运行工程中承受载荷的齿轮,如同悬臂梁,其根部受到脉冲的周期性应力超过齿轮材料的疲劳极限时,会在根部产生裂纹,并逐步扩展,当剩余部分无法承受传动载荷时就会发生断齿现象。齿轮由于工作中严重的冲击、偏载以及材质不均匀也可能引起断齿。5、齿面塑性变形在冲击载荷或重载下,齿面易产生局部的塑性变形,从而使渐开线齿廓的曲面发生变形。中国齿轮工业的发展中国齿轮工业在十五期间得到了快速发展2005年齿轮行业的年产值由2000年的240亿元增加到683亿元,年复合增长率23.27,已成为中国机械基础件中规模最大的行业。就市场需求与生产规模而言,中国齿轮行业在全球排名已超过意大利,居世界第四位。2006年,中国全部齿轮、传动和驱动部件制造企业实现累计工业总产值102628183千元,比上年同期增长24.15实现累计产品销售收入98238240千元,比上年同期增长24.37实现累计利润总额5665210千元,比上年同期增长26.85。2007年112月,中国全部齿轮、传动和驱动部件制造企业实现累计工业总产值136542841千元,比上年同期增长30.962008年110月,中国全部齿轮、传动和驱动部件制造企业实现累计工业总产值144529138千元,比上年同期增长32.92。中国齿轮制造业与发达国家相比还存在自主创新能力不足、新品开发慢、市场竞争无序、企业管理薄弱、信息化程度低、从业人员综合素质有待提高等问题。现阶段齿轮行业应通过市场竞争与整合,提高行业集中度,形成一批拥有几十亿元、5亿元、1亿元资产的大、中、小规模企业通过自主知识产权产品设计开发,形成一批车辆传动系(变速箱、驱动桥总成)牵头企业,用牵头企业的配套能力整合齿轮行业的能力与资源实现专业化、网络化配套,形成大批有特色的工艺、有特色的产品和有快速反应能力的名牌企业通过技改,实现现代化齿轮制造企业转型。十一五末期,中国齿轮制造业年销售额可达到1300亿元,人均销售额上升到65万元/年,在世界行业排名中达到世界第二。20062010年将新增设备10万台,即每年用于新增设备投资约60亿元,新购机床2万台,每台平均单价30万元。到2010年,中国齿轮制造业应有各类机床总数约40万台,其中数控机床10万台,数控化率25(高于机械制造全行业平均值17).中重型载货汽车齿轮我国中重型载货汽车齿轮用钢牌号较多,主要是为适应引进当时国外先进汽车技术的要求。50年代我国从原苏联里哈乔夫汽车厂引进当时苏联中型载货汽车即解放牌原车型生产技术的同时,也引进了原苏联生产汽车齿轮的20CrMnTi钢种。改革开放以后,随着我国经济建设的高速发展,为了满足我国交通运输的快速发展需要,从80年代开始,我国有计划地引进工业发达国家的各类先进机型,各类国外先进中重型载货汽车也不断引进。同时,我国大汽车厂同国外著名汽车大公司进行合作,引进国外先进汽车生产技术,其中包括汽车齿轮的生产技术。与此同时,我国钢铁冶炼技术水平也在不断提高,采用钢包二次冶炼及成分微调和连铸连轧等先进治炼技术,使得钢厂能生产出高纯净度、淬透性能带缩窄的齿轮用钢材,从而实现了引进汽车齿轮用钢的国产化,使我国齿轮用钢的生产水平上了一个新台阶。近年来,适合于我国国情的国产重型汽车齿轮用含镍高淬透性能钢也得到了开发和应用,取得了较好效果。汽车齿轮的热处理技术也从原5060年代采用井式气体渗碳护发展到当前普遍采用由计算机控制的连续式气体渗碳自动线和箱式多用炉及自动生产线包括低压真空渗碳技术、齿轮渗碳预氧化处理技术,齿轮淬火控制冷却技术由于专用淬火油和淬火冷却技术的使用、齿轮锻坯等温正火技术等。这些技术的采用不仅使齿轮渗碳淬火畸变得到了有效控制、齿轮加工精度得到提高、使用寿命得到延长,而且还满足了齿轮的现代化热处理的大批量生产需要。有关文献指出,汽车齿轮的寿命主要由两大指标考核,一是齿轮的接触疲劳强度,二是齿轮的弯曲疲劳强度。前者主要由渗碳淬火质量决定,后者主要由齿轮材料决定。为此,有必要对汽车齿轮用渗碳钢的要求、性能及其热处理特点有一个较全面的了解。9.19铬锰钛钢和硼钢长期以来,我国载货汽车齿轮使用最普遍的钢种是20CrMnTi。这是上世纪50年代我国从原苏联引进的中型的汽车齿轮18XTr钢种即20CrMnTi钢。该钢晶粒细,渗碳时晶粒长大倾向小,具有良好的渗碳淬火性能,渗碳后可直接淬火。文献指出,在1980年以前,我国的渗碳合金结构钢包括20CrbinTi钢在钢材出厂时只保证钢材的化学成分和用样品测定的力学性能,但是在汽车生产时常常出现化学成分和力学性能合格的钢材,由于淬透性能波动范围过大而影响产品质量的情况。例如若20CrMnTi渗碳钢的淬透性过低,则制成的齿轮渗碳淬火后,心部硬度低于技术条件规定的数值,疲劳试验时,齿轮的疲劳寿命降低一半若淬透性能过高,则齿轮渗碳淬火后内孔收缩量过大而影响齿轮装配。由于钢材淬透性能对轮齿心部的硬度和畸变都有极其重大的影响,1985年冶金部颁布了我国的保证淬透性结构钢技术条件GB521685,在此技术条件中列入了包括20CxMnTiH、20MnVBH钢在内的10种渗碳钢的化学成分、淬透性能数据。标准中规定用于制造齿轮的20CrMnTi钢的淬透性能指标为距水冷端9咖处的硬度为3042HRC。在此之后,采用20CrMnTi钢生产齿轮的齿心部硬度过低和畸变过大的问题基本上得到了解决。但是不管齿轮模数大小和钢材截面粗细均采用同一钢号20CrMnTi钢显然是不合理的。近年来,由于我国钢材冶炼技术水平的提高以及合金结构钢供应情况的改善,已经有条件把齿轮钢的淬透性能带进一步缩窄,并根据不同产品如变速器齿轮与后桥齿轮等的要求开发新的钢种以满足其要求。通过与钢厂协商,1997年长春一汽先后与生产齿轮钢厂的生产厂家签定了将20CrMnTi钢淬透性能分挡供应的协议,例如解放牌5t载货汽车上用于制造截面尺寸较小的变速器第一轴、中间轴齿轮和截面尺寸较大的后桥主、从动圆锥齿轮用20CrMnTiH钢淬透性能组别分别为I和Ⅱ,对应淬透性能分别为J93036HRC和J936~42HRC。1960年前后,由于我国镍、铬钢的供应紧张,影响了我国含镍、铬钢材的生产。而当时我国的汽车工业是从原苏联引进的技术,苏联大量应用含镍、铬的钢材。因此,当时我国汽车工业大力发展了硼钢的开发、研制工作,用20MnVB和20Mn2TiB钢代替20CrMnTi渗碳钢制造齿轮。这是因为在结构钢中加入微量硼0.00010.0035可以显著地提高钢材的淬透性能,因此钢中加入微量硼可以代替一定数量的锰、镍、铬、钼等贵重合金元素,因而硼钢得到广泛的应用。长春一汽曾在解放牌汽车齿轮生产中使用过20MnTiB和20Mn2TiB钢。东风汽车公司生产的东风牌5,载货汽车变速器和后桥齿轮分别采用20CrMnTi和20MnVB钢制造。同样,也与钢厂签定了把钢材淬透性能带缩窄并分档供应的协议。变速器和后桥主、从动圆锥齿轮用钢分别为20CrMnTiH3和20MnVBH2、20MnVBH3,对应淬透性能分别为J932~39HRC和J937~44HRC、J934~42HRC。我国綦江齿轮厂引进了德国公司的重型汽车变速器齿轮生产技术,在国内按德国Ⅲ公司的标准试制了该公司的CrMnB系含硼齿轮钢获得成功。其齿轮材料的淬透性能为J1031~39HRC当然,20CrMnTi钢及20MnTiB钢、20MVB钢等含硼钢也存在不足。一般认为20CrMnTi等渗碳钢是本质细晶粒钢,渗碳后晶粒不会粗化,可直接淬火。但实际上由于钢材冶炼质量的影响,常常在正常条件下发生晶粒粗化现象。对多批材料的实际晶粒度试验,发现相当部分实际晶粒度只有23级930℃保温3h条件下。文献认为,20CrMnTi由于Ti含量较高,钢中TiN夹杂物多,尤其是大块的TiN夹杂是齿轮疲劳时的疲劳源,它的存在会降低齿轮的接触疲劳性能。这种夹杂物呈立方结构,受力时易发生解理开裂,导致齿轮早期失效。另一个问题是该钢的淬透性能有限,不能满足大直径大模数齿轮的要求,渗碳有效硬化层深度和心部硬度均不能满足重型齿轮的要求。此外,在热处理过程中20CrMnTi钢易产生内氧化和非马氏体组织而降低齿轮的疲劳寿命。但目前在我国齿轮渗碳钢中还没有哪一种钢在渗碳工艺上有20CrMnTi钢这样成熟和可靠。所以,它仍是目前国内使用最普遍的渗碳钢种。20MnVB、20MnTiB和20Mn2TiB等硼钢也存在一些缺点,如在冶炼时由于脱氧去氮不好而使硼不能起到增加淬透性能的作用,因此,使硼钢的性能不稳定,渗碳淬火后的齿轮畸变增大而影响产品的质量。同时由于混晶和晶粒易于粗大,致变形不易控制和韧性较差,且硼钢齿轮根部易产生托氏体组织和碳氮共渗齿轮的黑网、黑带。因此,目前很多工厂中止使用该钢种。然而,决不能就此得出硼钢不适宜作齿轮渗碳钢的结论。含硼的渗碳钢在国外还有使用。例如,德国著名的Ⅳ齿轮厂,一直使用由其本厂拟订的保留钢种ZF7,这是一种含硼的低碳铬锰钢。该钢主要化学成分质量分数,为0.15~0.20C,0.15~0.40S,1.0~1.3Cr,1.0~1.3Mn,0.001~0.003B。美国汽车变速器齿轮和后桥主、从动齿轮有的也采用含硼渗碳钢,如50B15、43BVl4和94B17。因此,只要钢厂冶炼技术跟上去,硼钢的上述问题是能够解决的。20CrMnTiH、20MnVBH和20MnTiBH钢齿轮锻坯在连续式等温正火炉内进行处理可以保证得到均匀分布的片状珠光体铁素体。这样可以使齿轮的热处理畸变大大减小,使齿轮的精度提高,使用寿命延长。齿轮锻坯等温正火硬度为156~207HB。铬锰钼钢和铬钼钢22CrMnMo、20CrMnMoH和20CrMoH钢由于有着较高淬透性而用于中型汽车齿轮。此类钢可采用渗碳后直接淬火工艺。由于铬锰钼钢和铬钼钢中含有铬和钼等形成碳化物的元素,在渗碳过程中将促使轮齿表面碳含量增加,容易在渗碳层组织中出现大量碳化物,使渗碳层性能恶化。因此,齿轮采用铬锰钼钢和铬钼钢渗碳时,宜采用弱渗碳气氛,以防止形成过量碳化物。22CrMnMo和20CrMnMoH齿轮锻坯正火后在650~670℃进行高温回火处理,金相组织为细片状珠光体少量铁素体,硬度为171~229HB。20CrMnH齿轮锻坯最好在连续式等温正火炉中处理,935~945℃加热,640~650℃先预冷后等温,可获得均匀的铁素体珠光体组织,硬度为156~207HB。文献指出,20CrMoH钢冶炼工艺稳定,淬透性带较窄且易于控制,与20CrMnTi钢齿轮比较,具有热处理畸变小渗层有良好、稳定的淬透性金相组织、渗碳淬火后的表面和心部硬度,均能较好地满足技术要求疲劳性能好,比较适合汽车中小模数齿轮。综合考虑齿轮的服役条件,既保证齿轮的疲劳寿命,又减少齿轮的热处理畸变,在用以制造变速箱齿轮时应为J930~36HRC,用以制造后桥齿轮时应为J937~42HRC。9.21国外先进汽车齿轮用钢的国产化随着国外先进车型的引进,各种齿轮钢的国产化使我国的齿轮钢水平上了一个新台阶。目前,德国的CrMn钢,日本的CrMo系钢,和美国的SAE86钢满足了中小模数齿轮用钢。国产载货汽车齿轮有的采用美国牌号SAE8822H钢,如8t和10t桥用圆锥齿轮采用SAE8822H,该钢主要化学成分质量分数,为0.19~0.25C,0.70~1.05Mn,0.15~0.35Si,0.35~0.75Ni,0.35~0.65Cr,0.30~0.40Mo。文献认为,控制淬透性是解决齿轮畸变问题的关键。为减少畸变应选用Jominy淬透性带宽在4HRC以下的H钢。采用H钢的齿轮热处理后精度接触区比普通钢高70~80,使用寿命延长。因此,工业发达国家先后规定了渗碳合金结构钢的淬透性带。根据需要将淬透性带限制在很窄的范围4~5HRC。1在德国订货时,可以要求钢材的淬透性能在给定的范围内,也可以要求缩窄淬透性能的钢材。17CrNiM06非常适合制造大模数重负荷汽车齿轮,该钢主要化学成分质量分数,为0.15~0.20C,0.40~0.60Mn,1.50~1.80Cr,0.25~0.35Mo,1.40~1.70Ni。此钢在我国已开始生产和使用。文献认为,在17CrNiM06钢齿轮渗碳过程中,在适当降低渗碳后期碳势的同时加快渗碳后的冷却速度,由空冷改为风冷,阻止大块碳化物的形成,然后在630cC进行高温回火,以析出部分合金碳化物,为的是在820℃二次加热淬火时减少残留奥氏体量,最终获得较好的金相组织。2奥地利Styer重型汽车厂要求淬透性带宽为7HRC。3日本中重型货车,如日野牌KB222型载重9t汽车和日产牌CKL20DD型载货8t汽车的变速器齿轮及后桥齿轮广泛采用CrMo系钢,如SCM420H和SCM822H钢,相当于我国国产化20CrMnMoH和22CrMoH钢。此类钢具有较高的淬透性能。在一定范围内,齿轮的弯曲疲劳寿命随着淬透性的增加而提高。文献指出,长春一汽开始在生产解放牌9t载货汽车后桥齿轮时,采用20CrMnTiH钢,即使使用淬透性能为Ⅱ组的钢材J936~42HRC,热处理后齿轮轮齿心部硬度也只有22~24HRC,达不到齿轮技术条件规定的要求,汽车在使用时,后桥主动和从动圆锥齿轮发生早期损坏。因此不得不选用淬透性能更高的CtMo钢,其主要成分参考日本的SCM822H齿轮钢,该钢材的主要化学成分质量分数,为0.19~0.25C,0.55~0.90Mn,0.15~0.35Si,0.85~1.25Cr,0.35~0.45Mo。经与钢厂协商,生产出了国产化的新钢种22CrMoH钢,其淬透性能指标为J936~42HRC,较好地满足了汽车齿轮的使用要求。但是,该钢的工艺性能较差,齿轮锻坯要经过等温退火处理后才能进行切削加工,硬度为156~207HB,金相组织为先共析铁素体伪共析珠光体。此钢淬透性能较高,普通正火容易产生粒状贝氏体,粒状贝氏体的出现对切削加工极为不利,不仅使刀具的使用寿命大幅度下降,而且由于异常组织的出现,总是伴随着金相组织的不均匀性,最终造成齿轮热处理畸变的增大。4近年来,美国汽车制造厂家力图降低生产成本并提高零件的可靠性和耐久性,这就需要产品的几何尺寸及力学性能的高度一致。对热处理的零件要改善产品性能的一致性,必须降低零件淬火后硬度的分散程度,这就与钢的淬透性能带的宽窄程度有直接关系。齿轮心部硬度的一致性将减少热处理的畸变,从而提高齿轮的精度,并使轮齿表层的残余压应力分布更加均匀。美国载货汽车变速器齿轮和后桥主动圆锥齿轮用钢有的采用SAE8620钢和SAFA820钢制造。美国SAE8620H、SAE8822H等牌号钢在我国也已开始生产如宝钢集团上钢五厂等和使用,分别用于中型载货汽车变速器齿轮和后桥圆锥齿轮。9.22国内重型汽车齿轮用钢目前,我国齿轮钢基本满足使用和引进技术过程国产化的要求,而重型车传动齿轮及中重型车的后桥齿轮用钢,尚有待开发和生产。根据国内重型汽车的使用技术现状分析,超载使用和路况较差这两个问题较为严重,而且短期内无法克服,这就使齿轮经常承受较大的过载冲击载荷。过载冲击载荷介于疲劳和断裂应力之间,它对齿轮使用寿命有很大影响,往往造成齿轮早期失效。从这一点来说,大模数重负荷汽车齿轮应选择CrNi或CrNiMo系钢,如德国的17CrNiM06钢最好,还有国产20CrNi3H、20CrNiMoH钢。大功率发动机的问世促进了新型CrNiMo系列齿轮钢的开发和应用。如新型齿轮用钢20CrNi2Mo、17CrNiM06。一汽集团某汽车改装公司开发了一种新型载货汽车桥,其特点是匹配发动机的功率大。为保证齿轮的使用寿命,对齿轮的材料及质量有了更高的要求,原采用22CrMoH钢制成的后桥主动圆锥齿轮在使用过程中出现早期失效,严重时甚至出现断齿现象。在热处理方面,由于齿轮材料热处理工艺有时不够稳定,部分齿轮的有效硬化层不够,齿轮心部和表面硬度偏低,这些都是导致齿轮早期失效的主要原因。而且,Cr容易形成晶间网状碳化物,有损渗层力学性能。分析发现,齿轮轮齿心部硬度低时,过渡层塑性变形会引起渗碳层产生过高应力,因而导致渗碳层形成裂纹,最后使整个轮齿断裂。为此,根据斯太尔汽车桥后桥主动圆锥齿轮使用20CrNi3H钢的良好行车使用效果,应确保齿轮的有效硬化层深度在1.8~2.2mm,齿轮轮齿心部硬度在38~45HRC,齿轮表面硬度在60~64HRC,碳化物在1~3级,马氏体、残留奥氏体在1~4级,这样可使齿轮的使用寿命提高30~40。9.23粉末冶金齿轮粉末冶齿轮是少切屑、无切屑的高新技术的产物。虽然粉末冶金齿轮在整个粉末冶金零件中难以单独统计,但无论是按重量还是按零件数量,粉末冶金齿轮在汽车、摩托车中所占的比例都远远大干其他领域中的粉末冶金零件。因此,从汽车、摩托车在整个粉末冶金零件中所占比例的上升可以看出,粉末冶金齿轮在整个粉末冶金零件中处于飞速发展的地位。如果按零件特点来分,齿轮属于结构类零件,而结构类零件在整个铁基零件中所占的绝对重量也远远大于其他几类,粉末冶金零件。主要粉末冶金齿轮1凸轮轴齿形带轮凸轮轴齿形带轮是各种汽车发动机中普遍使用的粉末冶金零件,通过一次成形和精整工艺,不需要其他后处理工艺,可以完全达到尺寸精度要求,尤其是齿形精度。因此,与用传统机械加工方法制造相比,在材料投入和制造上都大大减少,它是体现粉末冶金特点的典型产品。粉末冶金零件配套举例配套类别零部件名称汽车发动机凸轮轴、曲轴正时带轮,水泵、油泵带轮,主动、从动齿轮,主动、从动链轮,凸轮,轴承盖,摇臂,衬套,止推板,气门导管,进、排气门阀座汽车变速箱各种高低速同步器齿毂及组件,离合器齿轮,凸轮、凸轮轴,滑块,换挡杆,轴套,导块,同步环摩托车零件从动齿轮及组件,链轮,起动棘爪,棘轮,星形轮,双联齿轮,副齿轮,变速齿轮,推杆凸轮,轴套,滑动轴承,定心套,从动盘,进、排气门阀座汽车、摩托车油泵各种油泵齿轮、齿毂,各种油泵转子,凸轮环汽车、摩托车减振器各种活塞,底阀座,导向座压缩机各种活塞,缸体,缸盖,阀板,密封环农机产品各种轴套,转子,轴承.其他分电器齿轮,行星齿轮,内齿盘,组合内齿轮,各种不锈钢螺母,磁极。GearGearGearisrelyingonthetoothmeshingtorquerotavirusmechanicalparts.Gearwithotherdentatemachineryparts,suchasawormgear,rack,transmission,whichcanrealizechangedthedirectionofrotationspeedandtorque,changethedirectionofmovementandchangethemovementforms,andotherfunctions.Owingtothehightransmissionefficiency,accurateandadvantagesoflargerangeofpowertransmissionratio,gearmechanismiswidelyusedinindustrialproducts,thedesignandmanufactureleveldirectlyaffectsthequalityofindustrialproducts.Geartoothbuckleeachgearwilldrivetheothergearstotransmitpower.Separatetwogears,chainscanalsobeapplied,caterpillar,onbothsidesofthebelttodrivegearandtransmissionpower.Basicintroduction.Intheapplicationoftransmissiongearappearedveryearly.MorethanthreehundredyearsBC,theancientGreekphilosopherAristotleinthemechanicalproblems,itexpoundsthebronzeorirongeartransmissionproblemofrotarymotion.InventedinancientChina,hasbeenappliedintheentiregeartrain.However,theancientgearismadeofwoodormetalmoulds,canonlytransferbetweenshaftrotarymotion,cannotguaranteethestabilityoftransmission,thebearingcapacityofthegeararealsosmall.Accordingtohistoricalrecords,in400200BCinancientChinahasalreadystartedtousegear,shanxiunearthedbronzegearsinourcountryisbyfartheoldestgearhadbeenfound,asareflectionofancientscienceandtechnologyachievementsofthisworkistogearmechanismasthecoremechanism.The17thcentury,peoplestartedtoresearch,canbedeliveredrighttoothshapeofthemovement.The18thcentury,Europeaftertheindustrialrevolution,theapplicationofgeartransmissionisincreasingdaybydaywidelyFirstthedevelopmentofcycloidalgear,thentheinvolutegear,untilthebeginningofthe20thcentury,involutegearhassetupafileintheapplication.Asearlyasin1694,FrenchscholarPhilippeDeLaHireforwardinvolutetoothshapecurvecanbeusedasinthefirstplace.In1733,theFrenchM.Camusputforwardthecommonnormaloftoothcontactmustbeonthecenterofthenode.Aauxiliaryinstantaneouscenterlinerespectivelyalongthebigwheelandlittlewheeloftheinstantaneouscenterlinepitchforpurerolling,andtheauxiliaryinstantaneouscenterlinesolidcouplingofauxiliarytoothshapeonthebigwheelandlittlewheelenvelopeformedbytwotoothprofilecurveisconjugatedtoeachother,thisisCamustheorem.IttakesintoaccountthetwotoothsurfacemeshingstateClearlyestablishedthemodernconceptaboutcontacttrajectory.In1765,SwissL.Eulerinvoluteprofileanalyticresearchmathematicalfoundation,illustratesapairofmeshinggears,thetoothprofilecurveoftheradiusofcurvatureandcurvaturecenterposition.Later,babiesfurthercompletethemethod,andisnowtheEuletbabiesequation.CancontributetotheapplicationofinvolutetoothprofileisRoteftWUlls,heputforwardthecentredistancechangewheninvolutegearhastheadvantagesoftheangularspeedratiounchanged.In1873,aGermanengineerHoppeisputforward,withdifferentnumberofteethofinvolutetoothprofileofgearinthepressureAngleischanged,thuslaidtheideologicalbasisofmodernshiftgear.Theendofthe19thcentury,generativeprincipleofgearcuttingmethodandusingtheprincipleofgearcuttingmachineandcuttingtoolappeared,aftermakingthegearmachiningwiththemorecomprehensivemeans,involuteprofileshowshighmoreoptimalsex.Teethmeshaslongasthegearcuttingtoolsfromthenormalpositionwhenmovingslightly,canusethestandardcuttercutoutthecorrespondingshiftgearsinmachinetool.In1908,theSwissMAAGdisplacementmethodisstudiedandmanufacturingexportasprocessinggearshaper,later,theBSS,AmericanAGMA,GermanyDINsuccessivelyputforwardmanykindsofmethodtocalculatethedeflectionofgear.Inordertoimprovetheservicelifeofthepowertransmissiongearandreduceitssize,inadditiontofrommaterial,heattreatmentandstructureimprovement,thecirculararctoothprofileofgearobtainedthedevelopment.In1907,theBritishFrankHumphrispublishedacirculararctoothprofileattheearliest.In1926,ruinativesEruestWildhaberapatentonthemethodofsurfacearctoothprofilehelicalgears.In1955,theSovietunionsM.L.NovikovcompletedpracticalresearchofarctoothprofilegearandgettheorderofLenin.In1970,theBritishRolhRoycecompanyengineersR.M.StuderachieveddoublecirculararcgearpatentintheUnitedStates.Thiskindofgearisnowincreasinglyattentionbypeople,intheproductionoftheshowThebenefits.Gearistobeabletomesheachothertoothedmachinepart,itsapplicationinthefieldofmechanicaltransmissionandthewholemachineryisextremelybroad.Moderngeartechnologyhasreachedthemoduleofgearo.004100mmGeardiameterby1mm150mOnthetransmittedpowercanreachhundredsofkilowattsSpeeduptohundredsofthousandsofrevolutionsperminuteThecircumferenceofthehighestspeedof300m/SEC.Withthedevelopmentofproduction,thegearoperationstability.1674Danishastronomerroemerfirstwithoutercycloidtoothprofilecurveisputforward,inordertogetstablerunninggear.Inthe18thcenturyindustrialrevolution,geartechnologygotrapiddevelopment,peoplehavemadealotofresearchongear.In1733theFrenchmathematiciancardmeterspublishedprofilemeshingbasiclawsIn1765theSwissmathematicianeulerproposedusinginvolutetoothprofilecurve.Emergedinthe19thcenturygearhobbingmachineandgearshaper,solvestheproblemofmassproductionandhighprecisiongear.In1900,fordforgearhobbingmachineisinstalledonthedifferentialdevice,canworkouthelicalgearongearhobbingmachine,gearhobbingmachinerollgrindingwheelgainedpopularity,generatingmethodprocessinggearofthelandslide,gearinvolutegearbecomethemostwidelyused.In1899,pullupthefirstimplementationoftheprojectofthemodifiedgear.Modifiedgearcannotonlyavoidwheeltoothrootcutting,canalsogathertogetherwithcenterdistanceandimprovethebearingcapacityofthegear.In1923AmericasWilderHubblefirstputforwardthecirculararctoothprofileofgear,1955Suehiscirculararcgeartocarriedonthethoroughresearch,circulararcgearisappliedintheproduction.Thegearbearingcapacityandefficiencyishigher,butitisnotasgoodasinvolutegearthatiseasytomanufacture,itremainstobefurtherimproved.Structureisintroduced.Usuallyhaveatooth,tooth,endface,themethodofthesurface,addendumcircleanddedendumcirclecircle,dividingcircle.1tooth,toothforshort,isthegearEveryonefortheconvexpartofthemesh,theconvexpartgenerallyradiatingarrangement,pairingtheteethofgearcontacteachother,canmakethegearsmeshcontinuousoperation2thetooth,isthespacebetweenthetwoadjacentteethonthegearsEndfaceiscylindricalorcylindricalwormgear,planeperpendiculartotheaxisofthegearorworm3method,isperpendiculartotheplaneofthegearstoothline4addendumcircle,isreferstothetoothtopround5dedendumcircle,referstothebottomofthechannelintheround6basecircle,theformationofinvolutelinesforpurerollingofround7dividingcircle,itisintheendcalculatethebenchmarkcirculargeargeometrysize.Geartoothprofilecanbe,thegearshape,toothshape,toothsurfaceandmanufacturingmethodssuchasclassification.Geartoothprofileincludingtoothprofilecurve,pressureAngle,depthanddeflection.Involutegearisrelativelyeasytomanufacture,sothemodernuseofgearinvolutegearmajority,withlesscycloidalgearandcirculararcgearapplications.IntheaspectofpressureAngle,thebearingcapacityofsmallpressureAnglegearsmallerAndpressureAngleofgear,thoughbearingcapacityishigher,butunderthesameinthetransmissiontorqueofbearingtheloadincrease,soonlyforspecialsituations.Andgeartoothdepthhasbeenstandardized,generallyadopthighstandardtooth.Theadvantageofdeflectiongearismore,inallkindsofmechanicalequipment.Inaddition,thegearcanalsoaccordingtoitsshapecanbedividedintocylindricalgear,bevelgear,thenoncirculargear,rack,worm,wormgearAccordingtothetoothlineshapecanbedividedintostraightgears,helicalgears,herringbonegear,gearcurveAccordingtothetoothssurfaceisdividedintoexternalgearandinternalgearAccordingtothemanufacturingmethodcanbedividedintocastingrollinggear,gear,gearcutting,sinteredgear,etc.Gearmanufacturingmaterialsandheattreatmentprocessonthegearbearingcapacityandsizeweighthasagreatinfluence.Untilthe1950s,gearusecarbonsteel,the60stoswitchtoalloysteel,andmultipurposesurfacehardenedsteelinthe70s.Accordingtothehardness,toothsurfacecanbedividedintosoftandhardtoothfacetwokindsoftoothsurfaces.Bearingcapacityislow,softtoothsurfacegearmanufacturingmoreeasily,butgoodrunningin,morerestrictionsonthesizeandweightwithoutstrictfortransmission,andasmallamountintheproductionofgeneralmachinery.Becausethegearpairs,relativelyheavyburdenonsmallwheels,soinordertomaketheworkinglifeofthegearisroughlyequalsize,smalltoothsurfacehardnessishigherthanthebigwheel.Hardtoothsurfacegearofhighbearingcapacity,itisafterthegearprecisioncutting,thenquenching,surfacehardeningorcarburizingandquenchingtreatment,inordertoimprovethehardness.But,intheheattreatmentdeformationofgearwillinevitablyproduce,soafterheattreatmentmustgrindorfinecutting,grinding,toeliminatetheerrorbecauseofthedeformationandimprovetheprecisionofgear.MaterialcompositionCommonlyusedsteelmanufacturinggearquenchedandtemperedsteel,hardenedsteel,carburizingandquenchingsteelandnitridingsteel.Slightlylowerthanthestrengthofthecaststeelforgingsteel,usedtosizethelargergearMechanicalpropertiesofgraycastironisbad,canbeusedfortheopengeartransmissioninlightloadNodularcastironcanpartiallyreplacesteelmanufacturinggearPlasticgearisusedforlightloadandmorerequirementsoflownoise,anditsgearpairs,thethermalconductivityiscommonlyusedinsteelgears.Futuregearisoverloaded,highspeed,highprecisionandhighefficiency,suchasdirection,andstrivetosmallsize,lightweight,longservicelifeandeconomicandreliable.Andgeartheoryandthedevelopmentofthemanufacturingprocesswillbefurtherstudythemechanismfortoothdamage,thisistoestablishareliablebasisforthestrengthcalculationmethod,istoimprovethegearbearingcapacityandextendthelifeofthegeartheoreticalfoundationDevelopmentrepresentedbycirculararctoothprofileofthenewtoothformStudyofnewgearmaterialandthenewprocesstomakegearStudyoftheelasticdeformationofgear,manufacturingandinstallationerrorandthedistributionoftemperaturefield,tocarryonthemodificationofgeartooth,soastoimprovegearrunningstability,andincreasethecontactareaoftooth,whenloadedwithsoastoimprovethebearingcapacityofthegear.Frictionandlubricationtheoryisabasicworkingearresearchandlubricationtechnology,researchonelastichydrodynamicpressurelubricationtheory,promotingthesyntheticlubricatingoilandproperlyjoinextremepressureadditivesintheoil,notonlycanimprovethebearingcapacityoftoothsurface,andalsocanimprovethetransmissionefficiency.1,thetoothsurfaceabrasionForopengeartransmissionorcontaindontcleanlubricatingoilclosedgeardrive,duetotherelativeslidingbetweenthemeshingtoothsurfaces,makesomehardgrindinggrainintothefrictionsurface,sothatthetoothprofilechange,lateralclearanceincreased,leadtotoothgearsothattheexcessivethinning.Ingeneral,onlywhenmixedabrasiveinlubricatingoil,willcausetoothsurfacesofabrasivewearintherunning.2,toothsurfaceglueForhighspeedheavyloadgearinthegeartransmission,becauseofthefrictionbetweenthetoothsurfaceislarger,relativevelocity,themeshingareatemperatureisexorbitant,once,andthebadlubricationconditionbetweentoothsurfacesoftheoilfilmwilldisappear,maketwotoothsurfaceofthemetalcontact,mutualbondingtooccur.Whenthetwotoothfacecontinuetorelativemotion,ahardtoothfacewillbepartofthetoothsurfaceofsoftmaterialofftoformgroovesalongtheslidingdirection.3,fatiguepittingMutualengagementoftwotoothcontact,actionandreactionbetweenthetoothsurfacecontactstressmakestheworksurface,thepositionofthemeshpointisthechange,andthegeardoisperiodicmotion,sothecontactstressischangeaccordingtothepulsecycle.Toothsurfaceforalongtimeundertheeffectofthealternatingcontactstress,themarkwillappearsmallcracksinthegeartoothsurface,withthepassageoftime,thiskindofcrackonthesurfacehorizontalextension,graduallyaftertheannularcrackformation,thetoothsurfaceofthesmallareaofspallingandformashallowpitsomefatigue.4,toothbrokenInrunningprojectstobearloadgearascantileverbeam,itsrootsbythepulseofperiodicstressexceedsthefatiguelimitofthegearmaterial,willproducecrackintheroot,andgraduallyexpand,whenunabletowithstandaloadtransmissionoccurswhentherestofbrokenteethphenomenon.Gearduetosevereshock,partialloadandintheworkmaterialUnevenmayalsocausethetoothbroke.5,toothsurfaceplasticdeformationUndertheimpactloadoroverloading,toothsurfacearepronetolocalplasticdeformation,thusmakeinvolutetoothprofileofthesurfacedeformation.ThedevelopmentofChinasgearindustryChinasgearindustrygotrapiddevelopmentinthe15duringgearindustryoutputvaluein2005toincrease2000yuanfrom24billionyuanin2000,thecompoundannualgrowthrateof23.27,inamechanicalcomponentshasbecomeChinaslargestindustry.Intermsofmarketdemandandthescaleofproduction,ChinasgearindustryintheworldrankinghasbeenmorethanItaly,fourthintheworld.In2006,theChineseallgears,transmissionanddrivecomponentsmanufacturingenterprisesachievethecumulativegrossindustrialoutputvalueof102.628183billionyuan,ayearonyeargrowthof24.15overthesameImplementationaccumulativetotalsalesincomeof98.23824billionyuan,ayearonyeargrowthof24.37overthesameImplementationaccumulativetotalprofitof5.66521billionyuan,ayearonyeargrowthof26.85overthesame.1December2007,theChineseallgears,transmissionanddrivecomponentsmanufacturingenterprisesachievethecumulativegrossindustrialoutputvalueof136.542841billionyuan,ayearonyeargrowthof30.96overthesameOctober12008,theChineseallgears,transmissionanddrivecomponentsmanufacturingenterprisesachievethecumulativegrossindustrialoutputvalueof144.529138billionyuan,ayearonyeargrowthof32.92overthesame.Chinagearmanufacturingcomparedwiththedevelopedcountriesthereisinsufficientcapacityforindependentinnovation,newproductdevelopmentisslow,themarketcompetition,enterprisemanagementisweak,theinformationizationlevelislow,thestaffoverallqualityimprovement.Gearindustryatpresentstageshouldthroughthemarketcompetitionandintegration,improvetheindustryconcentration,formingagrouptohavebillionsofyuan,500millionyuan,100millionyuanassetsinlarge,mediumandsmallenterprisesWithindependentintellectualpropertyrights,productdesignanddevelopment,formingabatchofvehicletransmissionsystemtransmissionanddriveaxleassemblyledbyenterprise,withleadingenterprisessupportingcapacityandthepowerofthegearindustryresourceintegrationRealizespecialization,network,formingalargenumberofdistinctivetechnique,distinctiveproductsandrapidresponseabilityoffamousbrandenterprisesThroughtechnicalrenovation,tomodernizethegearmanufacturingenterprisetransformation.Attheendoftheperiodof11thfiveyearplan,Chinagearmanufacturingsalescanreach130billionyuan,percapitasalesroseto650000yuan/year,industryintheworldrankingoftheworldssecond.In20062010willbe100000setsofnewequipment,investmentofabout6billionyuanayearfornewequipment,newmachine20000units,eachunitprice300000yuanonaverage.By2010,Chinagearmanufacturingshouldbeabout400000varioustypesofmachinetools,amongthem100000setsofCNCmachine,numericalcontrolratewas2517higherthanthatofmechanicalmanufacturetheindustryaverage.MediumdutytruckgearsMediumdutytruckgearwithsteelgradesmoreinourcountry,mainlyinordertoadapttotheintroductionofforeignadvancedautomotivetechnologyatthetime.50sinourcountryfromtheformerSovietunion,geoffmediumsizedtruckplanttheintroductionoftheSovietunionthatis,theliberationbrandoriginalmodelsproductiontechnologyatthesametime,alsointroducedtheformerSovietunionintheproductionofautomobilegear20crmntisteelgrade.Afterthereformandopeningup,withtherapiddevelopmentofChinaseconomicconstruction,inordertomeettherequirementsoftherapiddevelopmentoftransportationinourcountry,startinginthe80s,ourcountryinaplannedwaytointroduceallkindsofadvancedindustrialdevelopedcountries,allkindsofforeignadvancedmediumdutytruckisintroduced.Atthesametime,largecarfactoryinChinawithforeignfamousautomobilecompaniestocooperate,theintroductionofforeignadvancedautomobilemanufacturingtechnology,includingautomobilegearproductiontechnology.Atthesametime,Chinasironandsteelsmeltingtechnologylevelhasbeenimproved,basedonladleandsecondarysmeltingcompositionadjustmentandcontinuouscastingandrollingandotheradvancedsmeltingtechnology,makesthesteelmilltoproducehighpurityandhardenabilitybandnarrowgearsteel,soastorealizethelocalizationoftheintroductionofautomobilegearsteel,gearsteelinourcountrysproductionlevelonanewstep.Inrecentyears,suitableforChinasnationalconditionsofdomesticheavyautomobilegearcanusenickelhighhardenabilitysteelalsoobtainedthedevelopmentandapplication,hasobtainedthegoodeffect.Automobilegearheattreatmenttechnologyisalsofromtheoriginal5060swelltypegascarburizingandappliedtothecurrentwidelyusedbythecomputercontrolofcontinuousgascarburizingautomaticlineandboxtypemultipurposefurnaceandautomaticproductionlines,includinglowpressurevacuumcarburizingtechnology,thegearcarburizingoxidationprocessingtechnology,controlgearquenchingcoolingtechnologyduetotheuseofspecialoilquenchingandquenchingcoolingtechnology,gearforgingstockisothermalnormalizingtechnology,etc.Thesetechnologies,notonlymakethegearcarburizingandquenchingdistortionhasbeeneffectivelycontrolled,thegearmachiningaccuracywasimproved,prolongtheservicelife,butalsocanmeettheneedsofthemodernizationofthegearwiththemassproductionoftheheattreatment.Literatures,pointsoutthattheservicelifeofautomobilegearismainlycomposedoftwomajorindexevaluation,oneisthegearcontactfatiguestrengthandbendingfatiguestrengthofgear.Theformerismainlydecidedbycarburizingandquenchingquality,whichismainlydeterminedbythegearmaterial.Therefore,itisnecessaryforautomobilegearwiththerequirementofcarburizingsteel,propertiesandheattreatmentcharacteristicsamorecomprehensiveunderstanding.9.19chromiummanganesesteelandtitaniumboronsteelLongtermsince,ourcountryisthemostcommonlyusedtypesofsteeltruckgear20crmnti.Thisisintroducedinthe1950sinChinafromtheformerSovietunionmediumsizedautomobilegear18XTRsteeli.e.,20crmntisteel.Thissteeloffinegrains,graingrowthtendencywhencarburizingissmall,hasagoodperformanceofcarburizingandquenching,directquenchingaftercarburizing.Literaturepointsoutthatin1980yearsago,ourcountryofcarburizedalloystructuralsteel,including20crbintisteelinsteelfactoryonlyguaranteesteelwasusedtodeterminethemechanicalproperties,chemicalcompositionandusebutinautoproductionoftenappearwhenchemicalcompositionandmechanicalpropertiesofqualifiedsteel,duetothelargehardenabilitycanrangeandaffectthequalityofproducts.Forexampleif20crmnticarburizingsteelhardenabilityistoolow,ismadeofthegearaftercarburizingandquenching,hearthardnessislowerthanthetechnicalconditionsofnumericalvalue,fatiguetest,thefatiguelifeofgearlowerhalfIfhighhardenabilitycan,thegearinnerholeshrinkageaftercarburizingandquenchingwhichaffectthegearassembly.Duetosteelhardenabilityonthecorehardnessanddistortionofgearhastheextremelysignificanteffect,metallurgicaldepartmentin1985issuedtheguaranteeofourcountryhardenabilitystructuralsteeltechnicalconditionsGB521685,inthetechnicalconditionsonthe,including20cxmntih,20MNVBHsteel,thechemicalcompositionof10kindsofcarburizingsteel,hardenabilitydata.Specifiedinthestandard20crmntisteelhardenabilitycanbeusedinthemanufactureofgearindicatorforwatercooledendthehardnessof9coffeeplaceisfrom3042HRC.Afterthat,using20crmntisteelproductionhardwaslowandthedistortionofgearteeth,thecoreistoobigproblembasicallysolved.Butregardlessofthesizeofthemoduleofgearandsteelsectionthicknessallusethesamesteelgrade20crmntisteelisobviouslyunreasonable.Inrecentyears,duetotheimprovementofsteelsmeltingtechnologyinChinaandtheimprovementofalloystructuralsteelsupplysituation,hastheconditionofgearsteelhardenabilitybandfurthernarrowed,andaccordingtothedifferentproductssuchasthetransmissiongearandrearaxlegear,etc.therequirementsofthedevelopmentofnewsteelgradetomeettheirrequirements.Throughconsultationwithsteelmillsin1997,changchunfawhassignedwiththeproductionofgearsteelmanufacturerswillbe20crmntisteelhardenabilitycanFenDangsupplyagreement,suchasliberatedbrandonthe5ttruckusedinthemanufactureofsmallsizeofcrosssectionofthetransmissionshaft,intermediateshaftgear1andsectionsizelargerdrivingaxleanddrivenbevelgearwith20crmntihsteelhardenabilitycancategoryIandⅡrespectively,andthecorrespondinghardenabilityJ9respectively3036HRCandtheJ93642HRC.Around1960,duetothetightsupplyofnickel,chromiumsteelinourcountry,affectingthenickel,chromiumsteelproductioninChina.AtatimewhenChinasautoindustryfromtheformerSovietuniontointroducethetechnology,theSovietunion,alargeamountofapplicationofnickel,chromiumsteel.Therefore,whenthedevelopmentofChinasautoindustrytodeveloptheboronsteel,thedevelopmentwork,with20MNVBand20mn2tibsteelinsteadof20crmnticarburizingsteelgearmanufacturing.Thisisbecausetheaddtraceboroninsteel0.00010.0035cansignificantlyimprovethehardenabilityofsteelcan,sojointhetraceboroninsteelcansubstituteforacertainnumberofmanganese,nickel,chromium,molybdenumandotherpreciousmetalelements,thusboronsteelhasbeenwidelyused.Changchunfawhasbeenliberatedbrandautomobilegearusedintheproductionof20mntiband20mn2tibsteel.Dongfengautomobilecompanyproductionofdongfengbrand5,cargoautotransmissionanddrivingaxlegear,respectively,using20crmntiand20MNVBsteelmanufacturing.Similarly,alsosignedwiththesteelmill,steelhardenabilitybandnarrowandalongthesupplyagreement.Transmissionanddrivingaxleanddrivenbevelgearsteel20crmntihrespectively20MNVBH3and2,20MNVBH3,thecorrespondinghardenabilitycanrespectively3239HRCandtheJ9J93744HRC,J93442HRC.TheqijiangcountgearworksinourcountryhasintroducedtheGermancompanysheavyautotransmissiongearproductiontechnology,inthedomesticGermanⅢcompanystandardsofdevelopmentthecompanyCrMnBboronsteelgeartobesuccessful.ThehardenabilityofgearmaterialcanJ103139HRC9.19chromiummanganesesteelandtitaniumboronsteelLongtermsince,ourcountryisthemostcommonlyusedtypesofsteeltruckgear20crmnti.Thisisintroducedinthe1950sinChinafromtheformerSovietunionmediumsizedautomobilegear18XTRsteeli.e.,20crmntisteel.Thissteeloffinegrains,graingrowthtendencywhencarburizingissmall,hasagoodperformanceofcarburizingandquenching,directquenchingaftercarburizing.Literaturepointsoutthatin1980yearsago,ourcountryofcarburizedalloystructuralsteel,including20crbintisteelinsteelfactoryonlyguaranteesteelwasusedtodeterminethemechanicalproperties,chemicalcompositionandusebutinautoproductionoftenappearwhenchemicalcompositionandmechanicalpropertiesofqualifiedsteel,duetothelargehardenabilitycanrangeandaffectthequalityofproducts.Forexampleif20crmnticarburizingsteelhardenabilityistoolow,ismadeofthegearaftercarburizingandquenching,hearthardnessislowerthanthetechnicalconditionsofnumericalvalue,fatiguetest,thefatiguelifeofgearlowerhalfIfhighhardenabilitycan,thegearinnerholeshrinkageaftercarburizingandquenchingwhichaffectthegearassembly.Duetosteelhardenabilityonthecorehardnessanddistortionofgearhastheextremelysignificanteffect,metallurgicaldepartmentin1985issuedtheguaranteeofourcountryhardenabilitystructuralsteeltechnicalconditionsGB521685,inthetechnicalconditionsonthe,including20cxmntih,20MNVBHsteel,thechemicalcompositionof10kindsofcarburizingsteel,hardenabilitydata.Specifiedinthestandard20crmntisteelhardenabilitycanbeusedinthemanufactureofgearindicatorforwatercooledendthehardnessof9coffeeplaceisfrom3042HRC.Afterthat,using20crmntisteelproductionhardwaslowandthedistortionofgearteeth,thecoreistoobigproblembasicallysolved.Butregardlessofthesizeofthemoduleofgearandsteelsectionthicknessallusethesamesteelgrade20crmntisteelisobviouslyunreasonable.Inrecentyears,duetotheimprovementofsteelsmeltingtechnologyinChinaandtheimprovementofalloystructuralsteelsupplysituation,hastheconditionofgearsteelhardenabilitybandfurthernarrowed,andaccordingtothedifferentproductssuchasthetransmissiongearandrearaxlegear,etc.therequirementsofthedevelopmentofnewsteelgradetomeettheirrequirements.Throughconsultationwithsteelmillsin1997,changchunfawhassignedwiththeproductionofgearsteelmanufacturerswillbe20crmntisteelhardenabilitycanFenDangsupplyagreement,suchasliberatedbrandonthe5ttruckusedinthemanufactureofsmallsizeofcrosssectionofthetransmissionshaft,intermediateshaftgear1andsectionsizelargerdrivingaxleanddrivenbevelgearwith20crmntihsteelhardenabilitycancategoryIandⅡrespectively,andthecorrespondinghardenabilityJ9respectively3036HRCandtheJ93642HRC.Around1960,duetothetightsupplyofnickel,chromiumsteelinourcountry,affectingthenickel,chromiumsteelproductioninChina.AtatimewhenChinasautoindustryfromtheformerSovietuniontointroducethetechnology,theSovietunion,alargeamountofapplicationofnickel,chromiumsteel.Therefore,whenthedevelopmentofChinasautoindustrytodeveloptheboronsteel,thedevelopmentwork,with20MNVBand20mn2tibsteelinsteadof20crmnticarburizingsteelgearmanufacturing.Thisisbecausetheaddtraceboroninsteel0.00010.0035cansignificantlyimprovethehardenabilityofsteelcan,sojointhetraceboroninsteelcansubstituteforacertainnumberofmanganese,nickel,chromium,molybdenumandotherpreciousmetalelements,thusboronsteelhasbeenwidelyused.Changchunfawhasbeenliberatedbrandautomobilegearusedintheproductionof20mntiband20mn2tibsteel.Dongfengautomobilecompanyproductionofdongfengbrand5,cargoautotransmissionanddrivingaxlegear,respectively,using20crmntiand20MNVBsteelmanufacturing.Similarly,alsosignedwiththesteelmill,steelhardenabilitybandnarrowandalongthesupplyagreement.Transmissionanddrivingaxleanddrivenbevelgearsteel20crmntihrespectively20MNVBH3and2,20MNVBH3,thecorrespondinghardenabilitycanrespectively3239HRCandtheJ9J93744HRC,J93442HRC.TheqijiangcountgearworksinourcountryhasintroducedtheGermancompanysheavyautotransmissiongearproductiontechnology,inthedomesticGermanⅢcompanystandardsofdevelopmentthecompanyCrMnBboronsteelgeartobesuccessful.ThehardenabilityofgearmaterialcanJ103139HRC9.19chromiummanganesesteelandtitaniumboronsteelLongtermsince,ourcountryisthemostcommonlyusedtypesofsteeltruckgear20crmnti.Thisisintroducedinthe1950sinChinafromtheformerSovietunionmediumsizedautomobilegear18XTRsteeli.e.,20crmntisteel.Thissteeloffinegrains,graingrowthtendencywhencarburizingissmall,hasagoodperformanceofcarburizingandquenching,directquenchingaftercarburizing.Literaturepointsoutthatin1980yearsago,ourcountryofcarburizedalloystructuralsteel,including20crbintisteelinsteelfactoryonlyguaranteesteelwasusedtodeterminethemechanicalproperties,chemicalcompositionandusebutinautoproductionoftenappearwhenchemicalcompositionandmechanicalpropertiesofqualifiedsteel,duetothelargehardenabilitycanrangeandaffectthequalityofproducts.Forexampleif20crmnticarburizingsteelhardenabilityistoolow,ismadeofthegearaftercarburizingandquenching,hearthardnessislowerthanthetechnicalconditionsofnumericalvalue,fatiguetest,thefatiguelifeofgearlowerhalfIfhighhardenabilitycan,thegearinnerholeshrinkageaftercarburizingandquenchingwhichaffectthegearassembly.Duetosteelhardenabilityonthecorehardnessanddistortionofgearhastheextremelysignificanteffect,metallurgicaldepartmentin1985issuedtheguaranteeofourcountryhardenabilitystructuralsteeltechnicalconditionsGB521685,inthetechnicalconditionsonthe,including20cxmntih,20MNVBHsteel,thechemicalcompositionof10kindsofcarburizingsteel,hardenabilitydata.Specifiedinthestandard20crmntisteelhardenabilitycanbeusedinthemanufactureofgearindicatorforwatercooledendthehardnessof9coffeeplaceisfrom3042HRC.Afterthat,using20crmntisteelproductionhardwaslowandthedistortionofgearteeth,thecoreistoobigproblembasicallysolved.Butregardlessofthesizeofthemoduleofgearandsteelsectionthicknessallusethesamesteelgrade20crmntisteelisobviouslyunreasonable.Inrecentyears,duetotheimprovementofsteelsmeltingtechnologyinChinaandtheimprovementofalloystructuralsteelsupplysituation,hastheconditionofgearsteelhardenabilitybandfurthernarrowed,andaccordingtothedifferentproductssuchasthetransmissiongearandrearaxlegear,etc.therequirementsofthedevelopmentofnewsteelgradetomeettheirrequirements.Throughconsultationwithsteelmillsin1997,changchunfawhassignedwiththeproductionofgearsteelmanufacturerswillbe20crmntisteelhardenabilitycanFenDangsupplyagreement,suchasliberatedbrandonthe5ttruckusedinthemanufactureofsmallsizeofcrosssectionofthetransmissionshaft,intermediateshaftgear1andsectionsizelargerdrivingaxleanddrivenbevelgearwith20crmntihsteelhardenabilitycancategoryIandⅡrespectively,andthecorrespondinghardenabilityJ9respectively3036HRCandtheJ93642HRC.9.21theforeignadvancedautomobilegearsteelnationalizationWiththeintroductionofadvancedforeignmodels,allkindsofgearsteellocalizationofgearsteelinourcountryleveltoanewlevel.CrMnsteelatpresent,Germany,JapansCrMosteel,andtheUnitedStatesSAE86steeltomeetthemediumandsmallmodulegearsteel.DomestictruckgearusingthebrandSAE8822Hsteel,suchas8tandbevelgearsadoptSAE8822H10tbridge,themainchemicalcompositionofsteelmassfraction,of0.190.25Cand0.701.05MnandSiof0.150.35,0.350.75Ni,Crof0.350.65,0.300.40Mo.Documentsthatcontrolthehardenabilityisthekeytosolvetheproblemofdistortionofgear.ToreducethedistortionshouldchooseJominyunder4HRCofHsteelhardenabilitybandwidth.UsingHsteelprecisiongearafterheattreatmentcontactregion7080higherthanordinarysteel,prolongservicelife.Therefore,theindustrialdevelopedcountryhasstipulatedthecarburizingalloyconstructionalsteelhardenabilityband.Accordingtotheneedtolimithardenabilitybandinanarrowrangeof45HRC.1whenyouplaceanorderinGermanycanrequestthehardenabilityofsteelcanbeinagivenrange,alsocanasktonarrowhardenabilityofsteel.17crnim06verysuitableformanufacturinglargemoduleheavydutyautomobilegear,themainchemicalcompositionofsteelmassfraction,of0.150.20Cand0.400.60Mn,1.501.80Cr,Moof0.250.35,1.401.70Ni.Thesteelinourcountryhasbeguntheproductionanduse.Literaturethought,inthe17thcrnim06steelgearcarburizingprocess,whiledecreasethelatecarburizingcarbonpotentialtospeedupthecoolingspeedaftercarburizing,aircooledbyaircoolinginstead,preventtheformationoflargepiecesofcarbide,andhightemperaturetemperingat630cc,carbidealloyaspartofprecipitation,sothatat820℃secondquenchingtoreduceresidualaustenitevolume,eventuallyachievebettermicrostructure.2AustrianStyerheavycarfactoryaskedhardenabilitybandwidthfor7HRC.3Japanmediumdutytruck,suchashinobrandKB222typeloadtype9tcarsandnissanbrandCKL20DDcargo8tautomobiletransmissiongearandrearaxlegeariswidelyusedinCrMosteel,suchasSCM420HandSCM822Hsteel,equivalenttothelocalizationof20crmnmohand22crmohsteelinourcountry.Canthiskindofsteelhashighhardenability.Withinacertainrange,thebendingfatiguelifeofgearwiththeincreaseofhardenabilityandimprove.Literaturepointsout,changchunfawstartedintheproductionofliberationbrand9ttruckrearaxlegear,using20crmntihsteel,evenusingsteelhardenabilitycanⅡgroupJ93642HRC,thecenterofthegeartoothhardnessafterheattreatmentandonly2224HRC,shortoftherequirementsofthetechnicalconditionsofgear,thecaruse,rearaxledrivinganddrivenbevelgearoccurredearlydamage.SohadtochoosehigherCtMosteelhardenabilitycan,itsmaincompositionrefertoJapaneseSCM822Hsteelgear,themainchemicalcompositionofthesteelmassfraction,asfollows0.190.25Cand0.550.90MnandSiof0.150.35,0.851.25Cr,Moof0.35to0.45.Afterconsultingwithsteelmills,productionoutofthelocalizationofnewsteelgrade22crmohsteel,itshardenabilitycanindexfortheJ93642HRC,bettermeettheoperatingrequirementsofautomobilegear.However,theprocessperformanceofthesteelispoorer,gearforgingstocktoafterisothermalannealingtreatmenttomachining,hardnessis156207hb,metallographicorganizationfirsteutectoidferritefalseeutectoidpearlitic.Thissteelhardenabilitycanbehigh,ordinaryispronetofireofgranularbainiteandgranularbainiteappearveryadversetomachining,notonlymakesthetoollifedrastically,andsincetheemergenceofabnormaltissue,isalwaysaccompaniedbytheinhomogeneityofmicrostructure,resultingintheincreaseofgearheattreatmentdistortion.4inrecentyears,Americancarmanufacturerstoreduceproductioncostsandimprovereliabilityanddurabilityoftheparts,thisneedstheproductgeometricdimensionandmechanicalpropertiesofhighlyconsistent.Partsofheattreatmenttoimprovetheconsistencyofproductperformance,mustreducepartsquenchingafterthedispersiondegreeofhardness,itiswithsteelhardenabilitybandwidthdegreehasadirectrelationship.Theconsistencyofthehardnessofthegearthecorewillreduceheattreatmentdistortion,soastoimprovetheprecisionofgear,andthetoothsurfaceresidualcompressivestressdistributionmoreuniform.ThetrucktransmissiongearandrearaxleactiveconegearsteelmanufacturedSAE8620SAFA820steelandsteel.BrandssuchastheUnitedStates,SAE8620HSAE8822Hsteelinourcountryhasalsobeguntoproduction,suchasbaosteelgroupShanghaifactory,etc.anduse,formediumsizedtrucktransmissiongearandrearaxlecircularconegear.9.22thedomesticheavyautomobilegearsteelAtpresent,thegearsteelbasicmeettherequirementsofuseandtheintroductionoftechnicalprocessoflocalization,andheavyvehicletransmissiongearandmediumdutytruckrearaxlegearsteel,remainstobedevelopmentandproduction.Accordingtotheuseofdomesticheavydutytrucktechnologypresentsituationanalysis,usingoverloadandthetrafficisbadthesetwoproblemsaremoreserious,andcannotbeovercomeintheshortterm,thismakesthegearoftenoverloadunderhighimpactload.Betweenfatigueandfracturestressoverloadimpactload,andithasagreatinfluenceontheservicelifeofgear,oftenresultinprematurefailureofthegear.Fromthispoint,largemodulusofheavydutyautomobilegearshouldchooseCrNiandCrNiMosteel,suchasGermanys17crnim06steelisbest,anddomesticcrni3h20,20crnimohsteel.OfhighpowerenginedevelopedtopromoteanewtypeofCrNiMoseriesgearsteeldevelopmentandapplication.Asanewtypegearsteel20crni2mo,17crnim06.Fawgroupacarmodificationcompanydevelopedanewtypeoftruckbridge,characterizedbyamatchingenginepower.Inordertoguaranteetheservicelifeofgears,thegearmaterialandqualityhadthehigherrequest,theoriginalwith22crmohsteelintotherearaxleoftheinitiativetapergearfailureintheearlyintheprocessofusing,seriouswhenevenabrokentooth.Intermsofheattreatment,becausethegearmaterialheattreatmentprocessisnotstable,sometimeseffectivehardeninglayerisnotpartofthegear,gearthecoreandsurfacehardnessislow,thesearetheleadingcauseofprematurefailureofthegear.Moreover,Criseasytoformintergranularcarbidenetworkbeneathpermeabilitylayermechanicalproperties.Analysisfoundthatthecenterofthegeartoothhardnessislow,thetransitionlayerwillresultintheplasticdeformationofcarburizinglayertoomuchstress,resultingincarburizedlayercrackformation,finallythewholetoothfracture.Therefore,accordingtothesteyrautomobilerearaxlebridgeactivebevelgearsused20crni3hsteelgooddrivingeffect,shouldensurethateffectivehardeninglayerdepthofthegearin1.82.2mm,thecenterofthegeartoothin3845HRChardness,surfacehardnessofthegearinthe6064HRC,carbidein13,martensiteandretainedausteniteatlevel14,thismakestheservicelifeofthegearincreasedby3040.9.23powdermetallurgygearPowdermetallurgygearislesschip,chiptheproductofhighandnewtechnology.Althoughpowdermetallurgygearinthepowdermetallurgypartsisdifficulttoseparate,buteitherbyweightorbythenumberofparts,powdermetallurgyinautomobile,motorcyclegearproportionfardrypowdermetallurgypartsinotherareas.Therefore,fromautomobilesandmotorcyclesintheproportionofpowdermetallurgypartsincreasesasyoucansee,powdermetallurgygearinthepowdermetallurgypartsinapositionofrapiddevelopment.Characteristic,ifthepartsbelongstostructuralparts,gearandstructuralpartsintheentireironbasepartsofabsoluteweightalsoisfargreaterthanothercategories,powdermetallurgyparts.Thepowdermetallurgygears1thecamshaftcogbeltwheelcamshaftcogbeltwheeliswidelyusedinallkindsofautomobileengineofpowdermetallurgyparts,throughaformingandfinishingprocess,donotneedotherpostprocessingtechnology,canfullymeettherequirementsofdimensionalaccuracy,especiallythetoothprofileaccuracy.Therefore,comparedwithtraditionalmachiningmethodofmanufacture,onthematerialandmanufacturingaregreatlyreduced,itistypicallyreflectsthecharacteristicofpowdermetallurgyproducts.Powdermetallurgypartsofformacompleteset,forexampleMatchingcategoriespartsnamecarengineCamshaftandcrankshafttimingpulley,waterpump,oilpumppulley,thedrivinganddrivengears,activeanddrivensprocket,CAM,thebearingcover,rockerarm,bushing,thrustplate,valveguide,inletandexhaustvalveseatautomobilegearboxSynchronizergearhubandcomponents,allkindsofhighorlowspeedclutchgear,CAM,camshaft,slider,gearshift,bushings,guideshoe,synchronizingringsMotorcyclepartsDrivengearandcomponent,sprocket,ratchetstarting,ratchet,starwheel,duplexgear,gear,gearchange,thepushrodCAM,shaftsleeve,slidingbearing,centering,drivenplate,inletandexhaustvalveseatAutomobile,motorcycleoilpumpAllkindsofoilpumpgear,gearhub,allkindsofoilpumprotor,allkindsofautomobile,motorcycleshockabsorberpistonCAMring,bottomseat,leadtoallkindsofpistoncompressor,cylinderblock,cylinderhead,valveplate,allkindsofshaftsleeve,sealingringofagriculturalmachineryproducts,therotorbearings.TheotherWithinthedistributorgear,planetarygear,geardisk,internalgear,allkindsofstainlesssteelnut,magneticpole.

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