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 Philippe De La Hire 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 Eu-let-Savary 方程。对渐开线齿形应用作出贡献的是 Roteft WUlls，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 Frank Humphris最早发表了圆弧齿形。 1926年，瑞土人 Eruest Wildhaber 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 Rolh Royce 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 1-12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 30.96%； 2008年 1-10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。 2006-2010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50-60 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 (GB5216-85)，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 30-42HRC。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 ，对应淬透性能分别为 J9：30 36HRC和 J9=36 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(0.0001%-0.0035%)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 20CrMnTiH(3)和20MnVBH(2)、 20MnVBH(3)，对应淬透性能分别为 J9=32 39HRC和 J9=37 44HRC、J9=34 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 公司的标准试制了该公司的 Cr-Mn-B 系含硼齿轮钢获得成功。其齿轮材料的淬透性能为 J10=31 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 2 3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 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 J9=3036HRC，用以制造后桥齿轮时应为 J9=37 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 Cr-Mn钢，日本的 Cr-Mo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 0.190.25C， 0.70 1.05Mn， 0.15 0.35Si， 0.35 0.75Ni， 0.35 0.65Cr， 0.300.40Mo。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 Cr-Mo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 组的钢材 (J9=36 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 Ct-Mo 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， 0.851.25Cr， 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 J9=36 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 Cr-Ni 或 Cr-Ni-Mo 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Cr-Ni-Mo 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。 Gear Gear (Gear) is relying on the tooth meshing torque rotavirus mechanical parts.Gear with other dentate machinery parts, such as a worm gear, rack, transmission, which can realize changed the direction of rotation speed and torque, change the direction of movement and change the movement forms, and other functions.Owing to the high transmission efficiency, accurate and advantages of large range of power transmission ratio, gear mechanism is widely used in industrial products, the design and manufacture level directly affects the quality of industrial products.Gear tooth buckle each gear will drive the other gears to transmit power.Separate two gears, chains can also be applied, caterpillar, on both sides of the belt to drive gear and transmission power. Basic introduction. In the application of transmission gear appeared very early.More than three hundred years BC, the ancient Greek philosopher Aristotle in the mechanical problems, it expounds the bronze or iron gear transmission problem of rotary motion.Invented in ancient China, has been applied in the entire gear train.However, the ancient gear is made of wood or metal moulds, can only transfer between shaft rotary motion, cannot guarantee the stability of transmission, the bearing capacity of the gear are also small.According to historical records, in 400 200 BC in ancient China has already started to use gear, shanxi unearthed bronze gears in our country is by far the oldest gear had been found, as a reflection of ancient science and technology achievements of this work is to gear mechanism as the core mechanism.The 17th century, people started to research, can be delivered right tooth shape of the movement.The 18th century, Europe after the industrial revolution, the application of gear transmission is increasing day by day widely；First the development of cycloidal gear, then the involute gear, until the beginning of the 20th century, involute gear has set up a file in the application. As early as in 1694, French scholar Philippe De La Hire forward involute tooth shape curve can be used as in the first place.In 1733, the French M.C amus put forward the common normal of tooth contact must be on the center of the node.A auxiliary instantaneous center line respectively along the big wheel and little wheel of the instantaneous center line (pitch) for pure rolling, and the auxiliary instantaneous center line solid coupling of auxiliary tooth shape on the big wheel and little wheel envelope formed by two tooth profile curve is conjugated to each other, this is Camus theorem.It takes into account the two tooth surface meshing state；Clearly established the modern concept about contact trajectory.In 1765, Swiss L.E uler involute profile analytic research mathematical foundation, illustrates a pair of meshing gears, the tooth profile curve of the radius of curvature and curvature center position.Later, babies further complete the method, and is now the Eu - let - babies equation.Can contribute to the application of involute tooth profile is Roteft WUlls, he put forward the centre distance change when involute gear has the advantages of the angular speed ratio unchanged.In 1873, a German engineer Hoppe is put forward, with different number of teeth of involute tooth profile of gear in the pressure Angle is changed, thus laid the ideological basis of modern shift gear. The end of the 19th century, generative principle of gear cutting method and using the principle of gear cutting machine and cutting tool appeared, after making the gear machining with the more comprehensive means, involute profile shows high more optimal sex.Teeth mesh as long as the gear cutting tools from the normal position when moving slightly, can use the standard cutter cut out the corresponding shift gears in machine tool.In 1908, the Swiss MAAG displacement method is studied and manufacturing export as processing gear shaper, later, the BSS, American AGMA, Germany DIN successively put forward many kinds of method to calculate the deflection of gear. In order to improve the service life of the power transmission gear and reduce its size, in addition to from material, heat treatment and structure improvement, the circular arc tooth profile of gear obtained the development.In 1907, the British Frank Humphris published a circular arc tooth profile at the earliest.In 1926, rui natives Eruest Wildhaber a patent on the method of surface arc tooth profile helical gears.In 1955, the Soviet unions M.L.N ovikov completed practical research of arc tooth profile gear and get the order of Lenin.In 1970, the British Rolh - Royce company engineers R.M.S tuder achieved double circular arc gear patent in the United States.This kind of gear is now increasingly attention by people, in the production of the show The benefits. Gear is to be able to mesh each other toothed machine part, its application in the field of mechanical transmission and the whole machinery is extremely broad.Modern gear technology has reached: the module of gear o. 004 100 mm；Gear diameter by 1 mm 150 m；On the transmitted power can reach hundreds of kilowatts；Speed up to hundreds of thousands of revolutions per minute；The circumference of the highest speed of 300 m/SEC. With the development of production, the gear operation stability.1674 Danish astronomer roemer first with outer cycloid tooth profile curve is put forward, in order to get stable running gear. In the 18th century industrial revolution, gear technology got rapid development, people have made a lot of research on gear.In 1733 the French mathematician card meters published profile meshing basic laws；In 1765 the Swiss mathematician euler proposed using involute tooth profile curve. Emerged in the 19th century gear hobbing machine and gear shaper, solves the problem of mass production and high precision gear.In 1900, ford for gear hobbing machine is installed on the differential device, can work out helical gear on gear hobbing machine, gear hobbing machine roll grinding wheel gained popularity, generating method processing gear of the landslide, gear involute gear become the most widely used. In 1899, pull up the first implementation of the project of the modified gear.Modified gear can not only avoid wheel tooth root cutting, can also gather together with center distance and improve the bearing capacity of the gear.In 1923 Americas Wilder Hubble first put forward the circular arc tooth profile of gear, 1955 Sue his circular-arc gear to carried on the thorough research, circular arc gear is applied in the production.The gear bearing capacity and efficiency is higher, but it is not as good as involute gear that is easy to manufacture, it remains to be further improved. Structure is introduced. Usually have a tooth, tooth, end face, the method of the surface, addendum circle and dedendum circle circle, dividing circle. 1) tooth, tooth for short, is the gear Every one for the convex part of the mesh, the convex part generally radiating arrangement, pairing the teeth of gear contact each other, can make the gears mesh continuous operation； 2) the tooth, is the space between the two adjacent teeth on the gears；End face is cylindrical or cylindrical worm gear, plane perpendicular to the axis of the gear or worm3) method, is perpendicular to the plane of the gears tooth line 4) addendum circle, is refers to the tooth top round 5) dedendum circle, refers to the bottom of the channel in the round 6) base circle, the formation of involute lines for pure rolling of round 7) dividing circle, it is in the end calculate the benchmark circular gear geometry size. Gear tooth profile can be, the gear shape, tooth shape, tooth surface and manufacturing methods such as classification. Gear tooth profile including tooth profile curve, pressure Angle, depth and deflection.Involute gear is relatively easy to manufacture, so the modern use of gear involute gear majority, with less cycloidal gear and circular-arc gear applications. In the aspect of pressure Angle, the bearing capacity of small pressure Angle gear smaller；And pressure Angle of gear, though bearing capacity is higher, but under the same in the transmission torque of bearing the load increase, so only for special situations.And gear tooth depth has been standardized, generally adopt high standard tooth.The advantage of deflection gear is more, in all kinds of mechanical equipment. In addition, the gear can also according to its shape can be divided into cylindrical gear, bevel gear, the non-circular gear, rack, worm, worm gear；According to the tooth line shape can be divided into straight gears, helical gears, herringbone gear, gear curve；According to the tooths surface is divided into external gear and internal gear；According to the manufacturing method can be divided into casting rolling gear, gear, gear cutting, sintered gear, etc. Gear manufacturing materials and heat treatment process on the gear bearing capacity and size weight has a great influence.Until the 1950 s, gear use carbon steel, the 60 s to switch to alloy steel, and multi-purpose surface hardened steel in the 70 s.According to the hardness, tooth surface can be divided into soft and hard tooth face two kinds of tooth surfaces. Bearing capacity is low, soft tooth surface gear manufacturing more easily, but good running-in, more restrictions on the size and weight without strict for transmission, and a small amount in the production of general machinery.Because the gear pairs, relatively heavy burden on small wheels, so in order to make the working life of the gear is roughly equal size, small tooth surface hardness is higher than the big wheel. Hard tooth surface gear of high bearing capacity, it is after the gear precision cutting, then quenching, surface hardening or carburizing and quenching treatment, in order to improve the hardness.But, in the heat treatment deformation of gear will inevitably produce, so after heat treatment must grind or fine cutting, grinding, to eliminate the error because of the deformation and improve the precision of gear. Material composition Commonly used steel manufacturing gear quenched and tempered steel, hardened steel, carburizing and quenching steel and nitriding steel.Slightly lower than the strength of the cast steel forging steel, used to size the larger gear；Mechanical properties of gray cast iron is bad, can be used for the open gear transmission in light load；Nodular cast iron can partially replace steel manufacturing gear；Plastic gear is used for light load and more requirements of low noise, and its gear pairs, the thermal conductivity is commonly used in steel gears. Future gear is overloaded, high speed, high precision and high efficiency, such as direction, and strive to small size, light weight, long service life and economic and reliable. And gear theory and the development of the manufacturing process will be further study the mechanism for tooth damage, this is to establish a reliable basis for the strength calculation method, is to improve the gear bearing capacity and extend the life of the gear theoretical foundation；Development represented by circular arc tooth profile of the new tooth form；Study of new gear material and the new process to make gear；Study of the elastic deformation of gear, manufacturing and installation error and the distribution of temperature field, to carry on the modification of gear tooth, so as to improve gear running stability, and increase the contact area of tooth, when loaded with so as to improve the bearing capacity of the gear. Friction and lubrication theory is a basic work in gear research and lubrication technology, research on elastic hydrodynamic pressure lubrication theory, promoting the synthetic lubricating oil and properly join extreme pressure additives in the oil, not only can improve the bearing capacity of tooth surface, and also can improve the transmission efficiency. 1, the tooth surface abrasion For open gear transmission or contain dont clean lubricating oil closed gear drive, due to the relative sliding between the meshing tooth surfaces, make some hard grinding grain into the friction surface, so that the tooth profile change, lateral clearance increased, lead to tooth gear so that the excessive thinning.In general, only when mixed abrasive in lubricating oil, will cause tooth surfaces of abrasive wear in the running. 2, tooth surface glue For high-speed heavy-load gear in the gear transmission, because of the friction between the tooth surface is larger, relative velocity, the meshing area temperature is exorbitant, once, and the bad lubrication condition between tooth surfaces of the oil film will disappear, make two tooth surface of the metal contact, mutual bonding to occur.When the two tooth face continue to relative motion, a hard tooth face will be part of the tooth surface of soft material off to form grooves along the sliding direction. 3, fatigue pitting Mutual engagement of two tooth contact, action and reaction between the tooth surface contact stress makes the work surface, the position of the mesh point is the change, and the gear do is periodic motion, so the contact stress is change according to the pulse cycle.Tooth surface for a long time under the effect of the alternating contact stress, the mark will appear small cracks in the gear tooth surface, with the passage of time, this kind of crack on the surface horizontal extension, gradually after the annular crack formation, the tooth surface of the small area of spalling and form a shallow pit some fatigue. 4, tooth broken In running projects to bear load gear as cantilever beam, its roots by the pulse of periodic stress exceeds the fatigue limit of the gear material, will produce crack in the root, and gradually expand, when unable to withstand a load transmission occurs when the rest of broken teeth phenomenon.Gear due to severe shock, partial load and in the work material Uneven may also cause the tooth broke. 5, tooth surface plastic deformation Under the impact load or overloading, tooth surface are prone to local plastic deformation, thus make involute tooth profile of the surface deformation. The development of Chinas gear industry Chinas gear industry got rapid development in the 15 during: gear industry output value in 2005 to increase 2000 yuan from 24 billion yuan in 2000, the compound annual growth rate of 23.27%, in a mechanical components has become Chinas largest industry.In terms of market demand and the scale of production, Chinas gear industry in the world ranking has been more than Italy, fourth in the world. In 2006, the Chinese all gears, transmission and drive components manufacturing enterprises achieve the cumulative gross industrial output value of 102.628183 billion yuan, a year-on-year growth of 24.15% over the same；Implementation accumulative total sales income of 98.23824 billion yuan, a year-on-year growth of 24.37% over the same；Implementation accumulative total profit of 5.66521 billion yuan, a year-on-year growth of 26.85% over the same. 1 - December 2007, the Chinese all gears, transmission and drive components manufacturing enterprises achieve the cumulative gross industrial output value of 136.542841 billion yuan, a year-on-year growth of 30.96% over the same；October 1-2008, the Chinese all gears, transmission and drive components manufacturing enterprises achieve the cumulative gross industrial output value of 144.529138 billion yuan, a year-on-year growth of 32.92% over the same. China gear manufacturing compared with the developed countries there is insufficient capacity for independent innovation, new product development is slow, the market competition, enterprise management is weak, the informationization level is low, the staff overall quality improvement.Gear industry at present stage should through the market competition and integration, improve the industry concentration, forming a group to have billions of yuan, 500 million yuan, 100 million yuan assets in large, medium and small enterprises；With independent intellectual property rights, product design and development, forming a batch of vehicle transmission system (transmission and drive axle assembly) led by enterprise, with leading enterprises supporting capacity and the power of the gear industry resource integration；Realize specialization, network, forming a large number of distinctive technique, distinctive products and rapid response ability of famous brand enterprises；Through technical renovation, to modernize the gear manufacturing enterprise transformation. At the end of the period of 11th five-year plan, China gear manufacturing sales can reach 130 billion yuan, per capita sales rose to 650000 yuan/year, industry in the world ranking of the worlds second.In 2006-2010 will be 100000 sets of new equipment, investment of about 6 billion yuan a year for new equipment, new machine 20000 units, each unit price 300000 yuan on average.By 2010, China gear manufacturing should be about 400000 various types of machine tools, among them 100000 sets of CNC machine, numerical control rate was 25% (17% higher than that of mechanical manufacture the industry average). Medium-duty truck gears Medium-duty truck gear with steel grades more in our country, mainly in order to adapt to the introduction of foreign advanced automotive technology at the time.50 s in our country from the former Soviet union, geoff medium-sized truck plant the introduction of the Soviet union (that is, the liberation brand original models) production technology at the same time, also introduced the former Soviet union in the production of automobile gear 20 crmnti steel grade. After the reform and opening up, with the rapid development of Chinas economic construction, in order to meet the requirements of the rapid development of transportation in our country, starting in the 80 s, our country in a planned way to introduce all kinds of advanced industrial developed countries, all kinds of foreign advanced medium-duty truck is introduced.At the same time, large car factory in China with foreign famous automobile companies to cooperate, the introduction of foreign advanced automobile manufacturing technology, including automobile gear production technology.At the same time, Chinas iron and steel smelting technology level has been improved, based on ladle and secondary smelting composition adjustment and continuous casting and rolling and other advanced smelting technology, makes the steel mill to produce high purity and hardenability band narrow gear steel, so as to realize the localization of the introduction of automobile gear steel, gear steel in our countrys production level on a new step.In recent years, suitable for Chinas national conditions of domestic heavy automobile gear can use nickel high hardenability steel also obtained the development and application, has obtained the good effect.Automobile gear heat treatment technology is also from the original 50-60 - s well type gas carburizing and applied to the current widely used by the computer control of continuous gas carburizing automatic line and box-type multi-purpose furnace and automatic production lines, including low pressure vacuum carburizing technology), the gear carburizing oxidation processing technology, control gear quenching cooling technology (due to the use of special oil quenching and quenching cooling technology), gear forging stock isothermal normalizing technology, etc.These technologies, not only make the gear carburizing and quenching distortion has been effectively controlled, the gear machining accuracy was improved, prolong the service life, but also can meet the needs of the modernization of the gear with the mass production of the heat treatment. Literatures, points out that the service life of automobile gear is mainly composed of two major index evaluation, one is the gear contact fatigue strength and bending fatigue strength of gear.The former is mainly decided by carburizing and quenching quality, which is mainly determined by the gear material.Therefore, it is necessary for automobile gear with the requirement of carburizing steel, properties and heat treatment characteristics a more comprehensive understanding. 9.19 chromium manganese steel and titanium boron steel Long-term since, our country is the most commonly used types of steel truck gear 20 crmnti.This is introduced in the 1950 s in China from the former Soviet union medium-sized automobile gear 18 XTR steel (i.e., 20 crmnti steel).This steel of fine grains, grain growth tendency when carburizing is small, has a good performance of carburizing and quenching, direct quenching after carburizing.Literature points out that in 1980 years ago, our country of carburized alloy structural steel, including 20 crbinti steel) in steel factory only guarantee steel was used to determine the mechanical properties, chemical composition and use but in auto production often appear when chemical composition and mechanical properties of qualified steel, due to the large hardenability can range and affect the quality of products.For example if 20 crmnti carburizing steel hardenability is too low, is made of the gear after carburizing and quenching, heart hardness is lower than the technical conditions of numerical value, fatigue test, the fatigue life of gear lower half；If high hardenability can, the gear inner hole shrinkage after carburizing and quenching which affect the gear assembly. Due to steel hardenability on the core hardness and distortion of gear has the extremely significant effect, metallurgical department in 1985 issued the guarantee of our country hardenability structural steel technical conditions (GB5216-85), in the technical conditions on the, including 20 cxmntih, 20 MNVBH steel, the chemical composition of 10 kinds of carburizing steel, hardenability data.Specified in the standard: 20 crmnti steel hardenability can be used in the manufacture of gear indicator for water-cooled end the hardness of 9 coffee place is from 30-42 HRC.After that, using 20 crmnti steel production hard was low and the distortion of gear teeth, the core is too big problem basically solved.But regardless of the size of the module of gear and steel section thickness all use the same steel grade 20 crmnti steel is obviously unreasonable.In recent years, due to the improvement of steel smelting technology in China and the improvement of alloy structural steel supply situation, has the condition of gear steel hardenability band further narrowed, and according to the different products (such as the transmission gear and rear axle gear, etc.) the requirements of the development of new steel grade to meet their requirements. Through consultation with steel mills in 1997, changchun faw has signed with the production of gear steel manufacturers will be 20 crmnti steel hardenability can FenDang supply agreement, such as liberated brand on the 5 t truck used in the manufacture of small size of cross section of the transmission shaft, intermediate shaft gear 1 and section size larger driving axle and driven bevel gear with 20 crmntih steel hardenability can category I and respectively, and the corresponding hardenability J9 respectively: 30-36 HRC and the J9 = 36 42 HRC. Around 1960, due to the tight supply of nickel, chromium steel in our country, affecting the nickel, chromium steel production in China.At a time when Chinas auto industry from the former Soviet union to introduce the technology, the Soviet union, a large amount of application of nickel, chromium steel.Therefore, when the development of Chinas auto industry to develop the boron steel, the development work, with 20 MNVB and 20 mn2tib steel instead of 20 crmnti carburizing steel gear manufacturing.This is because the add trace boron in steel (0.0001% 0.0035%) can significantly improve the hardenability of steel can, so join the trace boron in steel can substitute for a certain number of manganese, nickel, chromium, molybdenum and other precious metal elements, thus boron steel has been widely used.Changchun faw has been liberated brand automobile gear used in the production of 20 mntib and 20 mn2tib steel. Dongfeng automobile company production of dongfeng brand 5, cargo auto transmission and driving axle gear, respectively, using 20 crmnti and 20 MNVB steel manufacturing.Similarly, also signed with the steel mill, steel hardenability band narrow and along the supply agreement.Transmission and driving axle and driven bevel gear steel 20 crmntih respectively 20 MNVBH (3) and (2), 20 MNVBH (3), the corresponding hardenability can respectively 32 39 HRC and the J9 J9 = = 37 44 HRC, J9 = 34 42 HRC. The qijiang count gear works in our country has introduced the German companys heavy auto transmission gear production technology, in the domestic German company standards of development the company Cr - Mn - B boron steel gear to be successful.The hardenability of gear material can J10 = 31 39 HRC 9.19 chromium manganese steel and titanium boron steel Long-term since, our country is the most commonly used types of steel truck gear 20 crmnti.This is introduced in the 1950 s in China from the former Soviet union medium-sized automobile gear 18 XTR steel (i.e., 20 crmnti steel).This steel of fine grains, grain growth tendency when carburizing is small, has a good performance of carburizing and quenching, direct quenching after carburizing.Literature points out that in 1980 years ago, our country of carburized alloy structural steel, including 20 crbinti steel) in steel factory only guarantee steel was used to determine the mechanical properties, chemical composition and use but in auto production often appear when chemical composition and mechanical properties of qualified steel, due to the large hardenability can range and affect the quality of products.For example if 20 crmnti carburizing steel hardenability is too low, is made of the gear after carburizing and quenching, heart hardness is lower than the technical conditions of numerical value, fatigue test, the fatigue life of gear lower half；If high hardenability can, the gear inner hole shrinkage after carburizing and quenching which affect the gear assembly. Due to steel hardenability on the core hardness and distortion of gear has the extremely significant effect, metallurgical department in 1985 issued the guarantee of our country hardenability structural steel technical conditions (GB5216-85), in the technical conditions on the, including 20 cxmntih, 20 MNVBH steel, the chemical composition of 10 kinds of carburizing steel, hardenability data.Specified in the standard: 20 crmnti steel hardenability can be used in the manufacture of gear indicator for water-cooled end the hardness of 9 coffee place is from 30-42 HRC.After that, using 20 crmnti steel production hard was low and the distortion of gear teeth, the core is too big problem basically solved.But regardless of the size of the module of gear and steel section thickness all use the same steel grade 20 crmnti steel is obviously unreasonable.In recent years, due to the improvement of steel smelting technology in China and the improvement of alloy structural steel supply situation, has the condition of gear steel hardenability band further narrowed, and according to the different products (such as the transmission gear and rear axle gear, etc.) the requirements of the development of new steel grade to meet their requirements. Through consultation with steel mills in 1997, changchun faw has signed with the production of gear steel manufacturers will be 20 crmnti steel hardenability can FenDang supply agreement, such as liberated brand on the 5 t truck used in the manufacture of small size of cross section of the transmission shaft, intermediate shaft gear 1 and section size larger driving axle and driven bevel gear with 20 crmntih steel hardenability can category I and respectively, and the corresponding hardenability J9 respectively: 30-36 HRC and the J9 = 36 42 HRC. Around 1960, due to the tight supply of nickel, chromium steel in our country, affecting the nickel, chromium steel production in China.At a time when Chinas auto industry from the former Soviet union to introduce the technology, the Soviet union, a large amount of application of nickel, chromium steel.Therefore, when the development of Chinas auto industry to develop the boron steel, the development work, with 20 MNVB and 20 mn2tib steel instead of 20 crmnti carburizing steel gear manufacturing.This is because the add trace boron in steel (0.0001% 0.0035%) can significantly improve the hardenability of steel can, so join the trace boron in steel can substitute for a certain number of manganese, nickel, chromium, molybdenum and other precious metal elements, thus boron steel has been widely used.Changchun faw has been liberated brand automobile gear used in the production of 20 mntib and 20 mn2tib steel. Dongfeng automobile company production of dongfeng brand 5, cargo auto transmission and driving axle gear, respectively, using 20 crmnti and 20 MNVB steel manufacturing.Similarly, also signed with the steel mill, steel hardenability band narrow and along the supply agreement.Transmission and driving axle and driven bevel gear steel 20 crmntih respectively 20 MNVBH (3) and (2), 20 MNVBH (3), the corresponding hardenability can respectively 32 39 HRC and the J9 J9 = = 37 44 HRC, J9 = 34 42 HRC. The qijiang count gear works in our country has introduced the German companys heavy auto transmission gear production technology, in the domestic German company standards of development the company Cr - Mn - B boron steel gear to be successful.The hardenability of gear material can J10 = 31 39 HRC 9.19 chromium manganese steel and titanium boron steel Long-term since, our country is the most commonly used types of steel truck gear 20 crmnti.This is introduced in the 1950 s in China from the former Soviet union medium-sized automobile gear 18 XTR steel (i.e., 20 crmnti steel).This steel of fine grains, grain growth tendency when carburizing is small, has a good performance of carburizing and quenching, direct quenching after carburizing.Literature points out that in 1980 years ago, our country of carburized alloy structural steel, including 20 crbinti steel) in steel factory only guarantee steel was used to determine the mechanical properties, chemical composition and use but in auto production often appear when chemical composition and mechanical properties of qualified steel, due to the large hardenability can range and affect the quality of products.For example if 20 crmnti carburizing steel hardenability is too low, is made of the gear after carburizing and quenching, heart hardness is lower than the technical conditions of numerical value, fatigue test, the fatigue life of gear lower half；If high hardenability can, the gear inner hole shrinkage after carburizing and quenching which affect the gear assembly. Due to steel hardenability on the core hardness and distortion of gear has the extremely significant effect, metallurgical department in 1985 issued the guarantee of our country hardenability structural steel technical conditions (GB5216-85), in the technical conditions on the, including 20 cxmntih, 20 MNVBH steel, the chemical composition of 10 kinds of carburizing steel, hardenability data.Specified in the standard: 20 crmnti steel hardenability can be used in the manufacture of gear indicator for water-cooled end the hardness of 9 coffee place is from 30-42 HRC.After that, using 20 crmnti steel production hard was low and the distortion of gear teeth, the core is too big problem basically solved.But regardless of the size of the module of gear and steel section thickness all use the same steel grade 20 crmnti steel is obviously unreasonable.In recent years, due to the improvement of steel smelting technology in China and the improvement of alloy structural steel supply situation, has the condition of gear steel hardenability band further narrowed, and according to the different products (such as the transmission gear and rear axle gear, etc.) the requirements of the development of new steel grade to meet their requirements. Through consultation with steel mills in 1997, changchun faw has signed with the production of gear steel manufacturers will be 20 crmnti steel hardenability can FenDang supply agreement, such as liberated brand on the 5 t truck used in the manufacture of small size of cross section of the transmission shaft, intermediate shaft gear 1 and section size larger driving axle and driven bevel gear with 20 crmntih steel hardenability can category I and respectively, and the corresponding hardenability J9 respectively: 30-36 HRC and the J9 = 36 42 HRC. 9.21 the foreign advanced automobile gear steel nationalization With the introduction of advanced foreign models, all kinds of gear steel localization of gear steel in our country level to a new level.Cr - Mn steel at present, Germany, Japans Cr - Mo steel, and the United States SAE86 steel to meet the medium and small module gear steel.Domestic truck gear using the brand SAE8822H steel, such as 8 t and bevel gears adopt SAE8822H 10 t bridge, the main chemical composition of steel (mass fraction, %) of 0.19 0.25 C and 0.70 1.05 Mn and Si of 0.15 0.35, 0.35 0.75 Ni, Cr of 0.35 0.65, 0.30 0.40 Mo.Documents that control the hardenability is the key to solve the problem of distortion of gear.To reduce the distortion should choose Jominy under 4 HRC of H steel hardenability bandwidth.Using H steel precision gear after heat treatment (contact region) 70% 80% higher than ordinary steel, prolong service life.Therefore, the industrial developed country has stipulated the carburizing alloy constructional steel hardenability band.According to the need to limit hardenability band in a narrow range of (4 5 HRC).1) when you place an order in Germany can request the hardenability of steel can be in a given range, also can ask to narrow hardenability of steel.17 crnim06 very suitable for manufacturing large module heavy duty automobile gear, the main chemical composition of steel (mass fraction, %) of 0.15 0.20 C and 0.40 0.60 Mn, 1.50 1.80 Cr, Mo of 0.25 0.35, 1.40 1.70 Ni.The steel in our country has begun the production and use.Literature thought, in the 17th crnim06 steel gear carburizing process, while decrease the late carburizing carbon potential to speed up the cooling speed after carburizing, air cooled by air cooling instead, prevent the formation of large pieces of carbide, and high temperature tempering at 630 cc, carbide alloy as part of precipitation, so that at 820 second quenching to reduce residual austenite volume, eventually achieve better microstructure.2) Austrian Styer heavy car factory asked hardenability bandwidth for 7 HRC.3) Japan medium-duty truck, such as hino brand KB222 type load type 9 t cars and nissan brand CKL20DD cargo 8 t automobile transmission gear and rear axle gear is widely used in Cr - Mo steel, such as SCM420H and SCM822H steel, equivalent to the localization of 20 crmnmoh and 22 crmoh steel in our country. Can this kind of steel has high hardenability.Within a certain range, the bending fatigue life of gear with the increase of hardenability and improve.Literature points out, changchun faw started in the production of liberation brand 9 t truck rear axle gear, using 20 crmntih steel, even using steel hardenability can group (J9 = 36 42 HRC), the center of the gear tooth hardness after heat treatment and only 22 24 HRC, short of the requirements of the technical conditions of gear, the car use, rear axle driving and driven bevel gear occurred early damage.So had to choose higher Ct - Mo steel hardenability can, its main composition refer to Japanese SCM822H steel gear, the main chemical composition of the steel (mass fraction, %) as follows: 0.19 0.25 C and 0.55 0.90 Mn and Si of 0.15 0.35, 0.85 1.25 Cr, Mo of 0.35 to 0.45.After consulting with steel mills, production out of the localization of new steel grade 22 crmoh steel, its hardenability can index for the J9 = 36 42 HRC, better meet the operating requirements of automobile gear.However, the process performance of the steel is poorer, gear forging stock to after isothermal annealing treatment to machining, hardness is 156 207 hb, metallographic organization first eutectoid ferrite + false eutectoid pearlitic.This steel hardenability can be high, ordinary is prone to fire of granular bainite and granular bainite appear very adverse to machining, not only makes the tool life drastically, and since the emergence of abnormal tissue, is always accompanied by the inhomogeneity of microstructure, resulting in the increase of gear heat treatment distortion.4) in recent years, American car manufacturers to reduce production costs and improve reliability and durability of the parts, this needs the product geometric dimension and mechanical properties of highly consistent.Parts of heat treatment to improve the consistency of product performance, must reduce parts quenching after the dispersion degree of hardness, it is with steel hardenability band width degree has a direct relationship.The consistency of the hardness of the gear the core will reduce heat treatment distortion, so as