农用车变速器总成的设计【含CAD图纸、说明书】
【温馨提示】压缩包内含CAD图有下方大图片预览,下拉即可直观呈现眼前查看、尽收眼底纵观。打包内容里dwg后缀的文件为CAD图,可编辑,无水印,高清图,压缩包内文档可直接点开预览,需要原稿请自助充值下载,所见才能所得,请见压缩包内的文件及下方预览,请细心查看有疑问可以咨询QQ:11970985或197216396
摘 要本文主要是针对 SF2310-4 时风低速货车所设计一款变速器,目的是达到较好的汽车动力性和燃油经济性性。变速器是车辆传动系统中不可或缺的一部分,本文通过选择适合的传动机构和零件结构,计算出变速器合适的重要参数,然后进行检验,设计出合理且适应现状的变速器。此变速器的齿轮均为标准齿轮,传动比、档位数都是根据发动机的关键参数确定得出的,保证了汽车优良的动力性能和较高的性价比。该变速器具有操纵简单、方便;传动效果好、制作简单、成本低廉、维修方便等特点,适合低速载货汽车。关键词:农用车;变速器;中间轴压缩包内含有CAD图纸和说明书,咨询Q 197216396 或 11970985AbstractThe main purpose of this paper is a design of transmission for SF2310-4 Shifeng low speed truck, the requirements are to achieve better vehicle dynamic quality and fuel economy. the essential part of the automobile transmission system is Transmission. By selecting the appropriate transmission mechanism and parts structure, this paper calculates the appropriate transmission parameters, and checks feasibility, then it designs a reasonable and adapt to the status of the transmission.The gears of the transmission are all standard gears. Gear numbers and transmission ratiomatch with engine parameters to ensure that the car has a good dynamic property and economic efficiency. The transmissions characteristics are the simple and convenient operation, high transmission efficiency, and easy manufacture, low cost and convenient maintenance. These are suitable for low speed truck.Key words: agricultural vehicle; transmission; intermediate shaftIII目 录II摘 要IIAbstractIII1 绪 论11.1 课题研究背景11.2 国内变速器的现状和发展趋势11.3 主要研究内容和研究意义22 变速器结构方案的确定32.1 传动机构布置方案分析32.2 固定轴式变速器32.3 齿轮安排32.4 倒档结构方案42.5 换档机构形式52.6 自动脱档53 变速器主要参数的确定63.1 变速器档数,传动比范围及各档传动比的确定63.2 变速器齿轮参数的确定83.3 各档齿轮齿数的分配114 渐开线圆柱齿轮几何尺寸的设计与计算165 齿轮强度的计算185.1 齿轮的弯曲强度计算185.2 齿轮的接触强度196 轴的设计与轴承的选择236.1 轴的设计236.2 轴的校核236.3 轴承的选择377 总结44参考文献45致 谢46第 1 章 绪论1 绪 论1.1 课题研究背景追溯到 19 世纪八十年代中期,全球首辆汽车诞生,之后它的变迁持续了大约 120 年。科技带领着汽车行业的快速发展,其全方位性能趋于完善。如今,汽车已然是全球人民生活与社会进步过程中异常重要的工具。如今的汽车要求好的传动系统与发动机相得益彰的配合,如此才能将汽车的优秀性能极致地表现出来,因此汽车变速器总成的设计显得尤为重要。随着党和国家扶持“三农”,建设社会主义新农村、推进城乡协调发展等一系列惠农政策的实施,并且我国农用汽车所具有的质量可靠耐用、价格低廉、中小吨位、中低速度等特点,这不仅使其能较好地符合农民的经济收入水平、对运输工具的要求及使用水平, 也能较好地满足农村不同种类用途的需要,从而使其农用汽车具有了巨大的现实需求和市场潜力。随着科技的进步,农用汽车发展趋势转变好,我国经济迅速发展,同时对农用汽车的要求也不断地提高,对农用汽车的经济性,动力性,舒适性,安全性的要求越发明显。1.2 国内变速器的现状和发展趋势回溯变速器技术的变迁过程就很显而易见,其作为传动系中十分关键的组成,它的技术发展,是一个判断汽车是否先进的标准。二十一世纪,诸如新型材料技术、能源和环境、信息和控制技术、先进制造技术科学技术进步的关键范畴,它们的更上一层楼进一步带动变速器技术的进步。由于不一样的区域市场的营销策略,变速器市场的成长趋向概括如下: 1)全球范围内,MT 的市场占有率将略有下降。2) 北美市场方面,AT 基础比较深,6AT 将要占据主导地位。3) 欧洲市场方面,手动变速器份额高,DCT 市场提高幅度大。4) 日本市场方面,CVT 将会进一步发展。5) 中国市场方面,多档 AT 市场占有率会慢慢上升,DCT 市场有慢慢扩张出去的趋势, AMT 在重型商用车与微型车方面也会有更广的用途,CVT 则适用于一些范畴的汽车。变速器技术的发展方向有以下几点:(1) 利用新式材料。材料科学和技术成为现世纪科技行业的核心力量。类型不一的新型材料应用在变速器中,成功地推进了汽车生产的发展,改善汽车性能。(2) 节能和环境保护。同时包含传动系统和发动机的环境保护和节约能源两方面。探索得到高效传动副从而达到节能的目的,同时运用润滑油或纯净的工作介质规避环境遭受破坏。依照发动机相异的特性与各式各样的工况,对变速器进行指向性设计,达到使传动高效,尽量不污染环境的目的。(3) 高性能、低噪声、精密度高、重量轻、寿命长、体积小、成本低。491.3 主要研究内容和研究意义本次设计的是农用汽车变速器,目的是解决运用中的动力不足的问题,通过对农用车变速器进行针对性地设计,可以增强农用车的动力性,提高其载货性能,增大爬坡度。本设计农用汽车变速器设置为四档变速器,通过增加挡位数,提高其燃油经济性。本设计目的是要符合现在低速货车的发展趋势,能满足市场的需求。金第 2 章 变速器结构方案的确定2 变速器结构方案的确定2.1 传动机构布置方案分析机械式变速器的优点有结构简单、高效率传动、运作持续和性价比高等,各种类型的汽车都采用这种,所以本次毕业设计选用机械式变速器。变速器的组成结构是变速传动机构和操纵机构。变速器有很多种类。 按照前进挡数划分,变速器可划分成三档,四档,五档与多档变速器。依照轴的形式,变速器有固定轴与转轴 2 种变速器。固定轴变速器的特点表现在是自动变速容易实现,发动机前置,双轴传动,前轮驱动。转轴主要用于液压机械传动。并且前者按轴的数量划分为两轴式、三轴式和多中间轴式变速器。2.2 固定轴式变速器变速器结构有两轴式变速器,三轴式变速器,多中间轴式变速器。(1) 两轴式常用在发动机前驱的乘用车上,优点是变速器传动比较小,结构简易,中间挡的传动效率高,而且噪音少。不过,当低档传动比较大时,结构尺寸也随之增大。而且,两轴式变速器不设置直接档,高档工作时齿轮产生较大的噪音,传动效率明显低下。显然与本设计要求不符。(2) 三轴式变速器常用在后驱的汽车上。其所有传动方式的共同点为:变速器一轴尾部和常啮合主动齿轮融为一体。一般方案都是二轴前部经轴承由一轴末端的孔承载, 同时让两轴中心线位于一条直线,经由啮合套的联结完成直接档。这样变速器传动高效, 90%以上是常态,工作时很安静、齿轮与轴承得以使用很久。而且传递动力时是两对齿轮, 在传动比相同的情况下大齿轮径向尺寸取小点,使得中心距,壳体相应尺寸都可减小。其劣势为在除了直接档的其它档位运转时,传动效率略略变低。如果档数一样,中间轴式变速器的差异表现在常啮合齿轮对数、档位布置顺序以及倒档传动方案等。因为此次设计对象为低速货车,且中间轴式五档和六档变速器太过笨重,传动比过大不符合本次设计要求,所以,选择三轴式四档变速器方案。只要档位采用常啮合齿轮传动,它的换档方式可以选择同步器或啮合套。在一种变速器中,换档方式既使用同步器,又使用啮合套的情况下,一定是高档位用同步器换档,低档位用啮合套换档。2.3 齿轮安排各齿轮副的安装位置一定程度上影响变速器的结构布置。如何安置各档的位置,从下述几方面考虑:(1) 整车总布置;(2) 驾驶员的使用习惯;这里值得一说的是倒档,它很特别,影响了排列组合方案。倒挡安置于变速器左边或右边,都可以实现,差异在于挂倒档时变换了驾驶员拨动变速杆的方向。为规避误挂倒挡, 常设有一个挂档时克服弹簧应运而生的作用力,提醒司机。就这方面考虑,图2 1(a)、(b) 的换档方案比图 2 1(c)的方案更合理。图 2 1(c)所示方案在挂一档时也要求克服用以规避风险换入倒档弹簧生成的作用力,这影响驾驶员的驾驶。另外,倒档的中央齿轮处在变速器左边或右边受力会不一样。图 2-1 变速杆换挡位置与顺序(3) 提高平均传动效率; (4)改善齿轮受载状况。变速器齿轮的选用类型有直齿圆柱齿轮和斜齿圆柱齿轮。斜齿圆柱齿轮的优点:工作平稳、使用寿命长、工作噪音少;缺点:工艺繁杂,容易产生轴向力,对轴承产生不利的影响。常啮合齿轮一般都是采用斜齿,虽然增大了齿数, 但同时增大了变速器的质量和转动惯量,对变速器的性能有所提升。直齿圆柱齿轮仅仅适用于低档和倒档,所以本设计选择的是倒档采用直齿,一、二、三、四档常啮合齿轮采用斜齿。2.4 倒档结构方案在结构布置上,要注意在不挂入倒挡时,不可以出现与第二轴齿轮发生啮合的情况。挂入倒挡时既要求过程顺利,又不允许与其余齿轮产生干涉。(a)(b)(c)(d)图 2-2 倒档布置方案图 2 2为常见的倒档布置方案。图 2 2(a)优点是使用中间轴上的一档齿轮,减小中间轴长度;就是对换档要求严格, 增加换挡难度。图 2-2(b)优点是较容易地获取大倒档传动比,就是过程不现实。图 2-2(c) 是把中间轴上的一、倒档齿轮做成一体,加长其齿宽。图 2-2(d)适用于常啮合齿轮副,换档比较轻松方便。因此,本设计选择方案(c)。2.5 换档机构形式变速器换档机构的形式:直齿滑动齿轮、同步器和啮合套。直齿滑动齿轮换档的缺点:轮齿端面产生冲击,发出噪音,磨损严重;引起司机紧张, 降低乘坐舒适性;换档行程长。不太适用于轻型汽车变速器。移动啮合套换档的优点:换档行程短,轮齿磨损小;但不能消除换档冲击,对驾驶员的技术需求较高。对档位要求不高或重型货车上的变速器才有所需求。同步器换挡的优点:操作快速、无冲击、不产生噪声,司机操作技术不熟练也可完美操纵,提高了汽车的各方面性能。与上述比较,虽然结构不简便、制造精度高、尺寸大, 但被广泛应用。本设计除倒挡以外都选用同步器换档。同步器的类型有常压式、惯性式和惯性增力式。其中,应用最广泛的是惯性式同步器。它的特点是换挡元件的角速度达到一致时才能换档,因而可以非常好地实现功能。本设计采用的是惯性式同步器。惯性式同步器按照结构分:有锁销式、滑块式、锁环式、多片式和多维式几种。他们结构各不相同,但是组成部分一般一致,都包含摩擦元件,锁止元件和弹性元件。本设计选用的是锁环式。2.6 自动脱档变速器无法正常运行的主要原因之一是自动脱档。自动脱档的原因有接合齿轮磨损、变速器轴刚度不够以及振动。解决这个问题从这两方面出发:一是工艺上采取办法,二是在结构上改善。结构方案有:错开两接合齿的啮合位置;切薄啮合齿套齿座上前齿圈的齿厚;接合齿之间形成倒锥角等。金第 3 章 变速器主要参数的确定3 变速器主要参数的确定表 3-1 农用车主要参数车辆名称:低速货车车辆类别:农用车中文品牌:时风牌英文品牌:公告批次:247免检:否发动机发动机生产企业排量(ml)功率(km)LL480QB SF480-2QC480Q(DI)山东华源莱动内燃机有限公司山东时风(集团)有限责任公司安徽全柴动力股份有限公司180918081809302829发动机商标:3000 2800 3000燃料种类:柴油(mm)外形尺寸:4310,4110*1600*1925(mm)货箱尺寸:2675,2475*1500*350(mm)总质量:2510(Kg)载质量利用系数:0整备质量:1390(Kg)额定载质量:990(Kg)接近角/离去角:27.5/27()前悬/后悬:1240,1040(mm)轴荷:轴距:2300(mm)轴数:2最高车速:681(km/h)油耗:GB21378-2008弹簧片数:6/4轮胎数:4轮胎规格:6.00-14,6.00-13前轮距:1285后轮距:1340制动前:制动后:制操前:液压制操后:本论文我们选取的农用车总质量为 2510kg,最高车速:68km/h,发动机额定转速下功率:29kw/3200(r/min),发动机最大转矩:97Nm/2200(r/min),机械式变速器,速比:5.568, 2.832,1.634,1.00,倒 5.011。农用车主要参数如表3 1。3.1 变速器档数,传动比范围及各档传动比的确定一、变速器档数的确定本设计应用于低速载货农用车上,选用四档变速器。二、各档传动比的确定初始参数见表 3-2。表 3-2 初始参数表项目参数发动机最大扭矩(2200r/min)97Nm发动机最大功率(3200r/min)29Kw空车整车质量1390kg满载整车质量2510kg最大时速68km/h最大爬坡度16.7主减速比5.568车轮滚动半径334mm确定最低档传动比,需要考虑的因素:汽车爬坡度,发动机最大转矩及主传动比等。下面假设主传动比已确定。a. 根据最大爬坡度确定一档传动比:因为汽车上坡行驶需要克服许多阻力,车速不高,忽略空气阻力,这时kmax f + imax(3-1)式中,kmax 最大驱动力;f滚动阻力;imax最大上坡阻力。又kmax= max 10 代入式(2-1),得:f = fmg cos maximax = sin mamax10 mg( cos 式中:max发动机最大扭矩;1变速器一档传动比;0主传动器传动比;max+ sin max) = 汽车传动系总效率, 取 90m汽车总质量; g重力加速度; 道路最大阻力系数; 驱动轮滚动半径;f滚动阻力系数, f 取 0.0150.02;max道路最大上坡角, 取 16.7。可得一档传动比:1max 0= 25109.80.2970.334 = 5.0198(3-2)97 5.568 0.9b. 根据驱动车轮与路面的附着条件得:max 10 (3- 3)2式中:2 汽车满载静止于水平路面时驱动桥给地面的载荷;道路的附着系数,取 0.50.6。因为货车后轴的轴荷分配范围为60%68% ,所以2 =25109.868 =16726.64N求得的变速器一档传动比:12max 0= 16726 .640.60.334 = 6.8959(3- 4)97 5.568 0.9结合式(2-2)和(2-4)得:5.0198 1 6.8959,取1 = (5.0198 + 6.8959)/2 = 5.958依据本设计要求的情况和以上条件可以初步得到一档传动比1 = 5.958。c. 确定最低档传动比和档数,根据理论公式得:1q =1的几何级数排列,式中 n 是档位数(n=4),四档传动比 = 1.00。q = 11= 35.9581= 1.81292= 5.9581.8129= 3.28653= 3.2865 = 1.81281.8129i4=1.00事实上传动比排列与理论值不太一样,以后会根据齿数再进行修改3.2 变速器齿轮参数的确定3.2.1 中心距 A 的确定中间轴式变速器的中心距是第一、第二轴轴线与中间轴轴线之间的距离。三轴式变速器中心距A,依据已有统计数据,根据经验公式,进行初步选择,可知:A = (1417) 3max式中: max发动机最大扭矩。(3-5)本设计变速器的中心距为:A = (1719.5)3max = (1719.5) 397 = 78.1190.98mm商用车类的变速器中心距的范围大概是80170mm,初选A = 100mm。3.2.2 壳体尺寸的确定变速器的横向尺寸可由齿轮直径、倒档齿轮和换档机构方案暂时拟定。其轴向尺寸则被档数、齿轮形式和换档机构形式影响。商用车变速器壳体的轴向尺寸:四档 (2.42.8)A 五档 (2.73.0)A 六档 (3.23.5)A中心距一般取以上范围的上限,为了方便检查,中心距 A 一般取整数。初选轴向尺寸:(2.42.8)A = (2.42.8) 100 = 240280mm3.2.3 模数决定齿轮模数有很多因素,其中最主要的因素是轮齿的弯曲疲劳强度或最大载荷作用下的静强度。现代汽车的变速器一般情况下是一档及倒档齿轮选择一种,高档齿轮选用另一种模数,其他各档齿轮模数应该在二者之间。在选择模数时,应当考虑降低变速器的噪声,则应增大齿宽,改小模数;减轻质量, 增大模数,齿宽和中心距一起减小。对于载货汽车,更应重视减轻质量。m 与弯曲应力之间的关系:直齿轮模数 = 3 2j f (3-6)式中:j计算载荷,Nm;应力集中系数,直齿齿轮取1.65;f摩擦力影响系数,主动齿轮取1.1,被动齿轮取0.9;z齿轮齿数;c齿宽系数,直齿齿轮取4.47.0;y 齿形系数,见图 2.2. 齿高系数 f 相同、节点处压力角不同时:14 .5 0.7920 ,17.5 0.8920 ,22.5 1.120 ,25 1.2320 ;压力角相同、齿高系数为 0.8 时,=0.8 1.14=1;w轮齿弯曲应力,当Ti = emax时,直齿齿轮的许用应力=400850MPa。图 3-1 齿形系数 y(当载荷作用在齿顶,=20,f0=1.0)根据参考同类车型,初步选择第一轴的轴齿轮齿数z = 17,根据图 3-1 得y = 0.12。由公式(3-6)得:m = 3 2j f =3297103 1.65 1.1 2.453.15c w3.14 174.40.12(400850)表 3-3 是汽车变速器齿轮模数范围表 3-3 齿轮法向模数n车型微型、轻型轿车中级轿车中型货车重型汽车n2.252.752.7533.504.54.506模数必须按照国标 GB1357-78 规定选择(表 3-3)表 3-4 各档常用齿轮模数(mm)11.251.5-2-2.5-3-1.75-2.25-2.75-4-5-6-3.253.53.75-4.5-5.5-3.25参照表 3-1 和表 3-2 知同类车型选取m = 3.5。3.2.4 齿形、压力角和螺旋角齿轮齿形、压力角和螺旋角按下表 3-5 取值。表 3-5 齿形、压力角和螺旋角项目车型齿形压力角(度)螺旋角(度)轿车高齿并修形14.5、15、16、16.52545一般货车标准齿轮GB1356-78202030重型车标准齿轮GB1356-78低档、倒档 22.5、25小螺旋角变速器齿轮一般选用的压力角为 20。本设计的所有齿轮选用标准齿轮。在变速器中,斜齿轮应用也较为广泛。结合本设计要求选螺旋角 = 25。3.2.5 齿宽在选择齿宽时,应该了解齿宽大小影响的对象有:轴向尺寸、质量、齿轮工作平稳度、齿轮强度等。如果想要最大限度地缩短轴向尺寸和减轻质量,就要选用小齿宽。可是,减小齿宽的缺点是斜齿轮传动不够平稳。这时,虽然可通过增大螺旋角进行补救,但是会增大轴承需承受的轴向力,降低了使用寿命,要慎重选择。依据来选择齿宽:b = cn(3-7)式中:c齿宽系数,直齿齿轮取4.47.0,斜齿齿轮取7.08.6;n法面模数。由公式(3 7)得: = (4.47.0) 3.5 = 15.424.5mm, 斜 = (7.08.6) 3.5 = 24.530.1mm齿宽的选择:常啮合齿轮副:中间轴上的齿轮b = 16mm, 第一轴齿轮b = 18mm; 档:中间轴上齿轮 b = 27mm, 对应的一档齿轮b = 27mm;档:中间轴上齿轮b = 25mm, 对应的二档齿轮b = 25mm; 档:中间轴上齿轮b = 27mm, 对应的三档齿轮b = 27mm; 倒档:b = 21mm, b = 19mm。3.2.6 齿顶高系数现在齿轮的齿顶高系数 0 = 1.0(通常汽车变速器齿轮都选用)。于是本设计选取齿顶高系数0 = 1.0。3.3 各档齿轮齿数的分配在初步选择了轴向尺寸、中心距、档位数、传动比及齿轮模数这些主要参数后,画结构方案简图,分配各档齿数。图 3 2是传动方案简图。3.3.1 确定一档齿轮的齿数已知一档传动比,且:1= 2718(3-8)齿数和h :图 3-2 四档变速器传动方案简图直齿轮:h= 2(3-9)斜齿轮:h= 2 cos 考虑第一轴轴承孔的限制和装配的可行性,一档齿轮齿数不能选多。货车中间轴上一档小齿轮齿数在1217之间选用。一档大齿轮齿数用7 = h 8计算求得。由公式(3-9)得:hz = 2 cos = 2100 cos 25 51.793.5初选h = 60,由以上计算和选用了标准齿轮(即要求齿数不要小于 17),所以8 = 17,那么7 = 60 17 = 43。3.3.2 修正中心距 A由于计算出的7和8不是整数,应对中心距进行修正。由公式(3 9)得:A = (3.5 60)/2 = 105mm3.3.3 确定常啮合传动齿轮副的齿数由公式(3 8)得2 = 8(3-10)11 7由于常啮合传动齿轮的中心距与一档齿轮的中心距相等,则:A = n(1+2)2 cos (3-11)解方程式求1与2,1、2取整数;然后核算一档传动比,再根据计算的齿数,按公式(3 11)修正螺旋角。联列 公式(3-10)和公式(3-11)得2 = 181 7 2 = 5.958 17 2.355 ( + ),解得143,故1 = 17,2 = 37A = n 12 2 cos 1 + 2 = 54由公式(3-11)算出精确的螺旋角:A = n(1 + 2)2 cos = arc cos (1 + 2)2= arc cos 3.5 542 105= 25.843.3.4 确定其它档位的齿轮齿数二档齿轮是斜齿,螺旋角6与2不一样时,可知:2= 2516(3-12)而A = n(5+6)2 cos 6初选6 = 20,由公式(3-12)和公式(3-13)得:(3-13) 2= 2516 A = n(5 + 6)2 cos 6试凑出5 = 32,6 = 22,此时2 = 3.166。此外,从消除或减少中间轴上的轴向力角度考虑,应必须满足下式:tan 2 =2(1 + 5)(3-14)tan 61+26由公式(3-14)得: tan 2 = tan 25.84 = 1.331tan 6tan 202 (1 + 5) = 37 (1 + 32) = 1.382满足设计要求。1+265422三档齿轮是斜齿,螺旋角4与2不一样时,可知:3= 2314(3-15)而A = n(3+4)2 cos 4(3-16)查手册得4 = 26,由公式(3-15)和(3-16)得: 3= 2314 A = n(3 + 4)2 cos 4试凑出3 = 25,4 = 30,此时 3 = 1.863。此外,从消除或减少中间轴上的轴向力角度考虑,应必须满足下式:tan 2 =2(1 + 3)(3-17)tan 41+24由公式(3-17)得: tan 2 = tan 25.84 = 1.039tan 4tan 252 (1 + 3) = 37 (1 + 25) = 1.056满足设计要求。1+2454303.3.5 确定倒挡齿轮副的齿数正常情况下,一档与倒挡取一样的模数,一般倒档齿轮齿数 10 取值范围是 2123。那么中间轴与倒挡轴之间的中心距为: = m(8 + 10)/2(3-18)初选10 = 22,由公式(3 18)得: = m(8 + 10)/2 = 3.5 (17 + 22)/2 = 68.25mm保证倒档齿轮在啮合时不与其它齿轮产生干涉,齿轮8 和 9的齿顶圆之间保持有0.5mm以上的间隙,则:a8 + a9 = 0.5(3-19)22由公式(3-19)得:8= 8= ncos 8=3.5cos 25.84 17 = 66.1mma = n = 3.5a8 = 8 + 2a = 66.1 + 2 3.5 = 73.1a9 = 2 a8 1 = 2 68.25 73.1 1 = 62.4mm9 =a9 2a = 62.4 2 3.5 = 55.4根据9 选择齿数,取9 = 17。然后,计算倒挡与第二轴的中心距: = m(7 + 9 )/2(3-20)由公式(3 20)得: = m(7+ 9) = 3.5 (43+ 17) = 105mm22 = 2107=3822 43 7.32 R189 1717 17综合上述计算,修正一下各档传动比(见表 3-6)。表 3-6 各档传动比档位IIIIIIIV倒档传动比5.958:13.166:11.863:11:17.32:1金第 4 章 渐开线圆柱齿轮几何尺寸的设计与计算4 渐开线圆柱齿轮几何尺寸的设计与计算一档齿轮副:8= 17d = n cos z =3.5cos 25.84 17 = 53.5a= + 2a= 53.5 + 2 3.5 = 60.5f = 2f = 53.5 2 3.5 1.25 = 44.757174.2= 43d = ncos z =3.5cos 25.84 43 = 167.2 a= + 2a= 167.2 + 2 3.5 =二档齿轮副:f = 2f = 167.2 2 3.5 1.25 = 158.4592.56= 22d = n cos z =3.5cos 25.84 22 = 85.5a= + 2a= 85.5 + 2 3.5 =f = 2f = 85.5 2 3.5 1.25 = 76.755= 32d = n cos z =3.5cos 25.84 32 = 124.5a= + 2a= 124.5 + 2 3.5 = 131.5三档齿轮副:f = 2f = 124.5 2 3.5 1.25 = 115.754= 30d = n cos z =3.5cos 25.84 30 = 116.5a= + 2a= 116.5 + 2 3.5 = 123.5f = 2f = 116.5 2 3.5 1.25 = 107.753104.5= 25d = n cos z =3.5cos 25.84 25 = 97.5a= + 2a= 97.5 + 2 3.5 =f = 2f = 97.5 2 3.5 1.25 = 88.75四档齿轮副:1= 17d = n cos z =3.5cos 25.84 17 = 53.5a= + 2a= 53.5 + 2 3.5 = 60.5f = 2f = 53.5 2 3.5 1.25 = 44.752= 37 = ncos z =3.5cos25 .84 37 = 144 a= + 2a= 144 + 2 3.5 = 151f = 2f = 144 2 3.5 1.25 = 135.25倒档齿轮副:10 = 22d = mz = 3.5 22 = 77a = + 2a = 77 + 2 3.5 = 84f = 2f = 77 2 3.5 1.25 = 68.259 = 17d = mz = 3.5 17 = 59.5a = + 2a = 59.5 + 2 3.5 = 66.5f = 2f = 59.5 2 3.5 1.25 = 50.75金第 5 章 齿轮强度的计算5 齿轮强度的计算5.1 齿轮的弯曲强度计算5.1.1 一档斜齿轮弯曲应力:式中:w= 2i cos 3 (5-1)i计算载荷,N mm;应力集中系数,斜齿齿轮取1.50;m齿轮模数; Z齿轮齿数;c齿宽系数,斜齿齿轮取 7.08.6;重合度影响系数,斜齿齿轮取2.0;y齿形系数,见图 3 1. 齿高系数 f 相同、节点处压力角不同时:14.5 0.7920 ,17.5 0.8920 ,22 .5 1.120 ,25 1.2320 ;压力角相同、齿高系数为 0.8 时,=0.8 1.14=1; = 0.47;斜齿轮螺旋角( ), = 25.84;w轮齿弯曲应力,当 = emax 时,斜齿齿轮的许用应力=100250MPa。一档齿轮副:主动齿轮8 = 17,从动齿轮7 = 43一档主动齿轮 = emax12 = 97 43/17 245.35Nm8的弯曲强度,由公式(5 1)得:w= 2i cos 3 = 2 245.35 1.5 cos 25.84 10003.14 3.53 17 0.47 (7.08.6) 2 43.98971.611一档从动齿轮的计算载荷i = emax 1 = 97 5.958 = 577.926Nm从动齿轮7的弯曲强度:w= 2i cos 3 = 2 577.926 1.5 cos 25.84 10003.14 3.53 43 0.47 (7.08.6) 2 40.96666.687满足弯曲强度的设计要求。5.1.2 二档斜齿轮弯曲应力:当计算载荷 取值为最大转矩emax时,斜齿轮许用弯曲应力在 100250MPa, 查文献2,3-4得, = 320 MPa。由公式(5 1)得:w= 2i cos 3 =2 97 cos25.84 1.50 10003.14 32 3.53 2 0.47 (7.08.6) 7. 9.239Mpa 满足设计要求。5.1.3 倒档齿轮弯曲应力倒档齿轮副:因为倒档齿轮好比一个惰轮,因此主动齿轮是 z8 = 17,从动齿轮是10 = 22。通过惰轮后主动齿轮是 9 = 17,从动轮是 7 = 43。 = = 97 (43) (22) 317.52Nmiemax 128101717通过倒挡齿轮前,10 = 22的弯曲强度是:= 2i f3 =2 317.52 1.65 0.9 10003.14 3.53 22 (4.47.0) 0.12 397.05603.03通过倒挡齿轮后主动轮是9 = 17,从动轮是7 = 43。9的i = emax12810= 97 ( 43) (22) 317.52Nm1717= 2i f3 =2 317.52 1.65 1.1 10003.14 3.53 17 (4.47.0) 0.12 599.54953.817的计算载荷i = emaxR = 97 7.32 = 710.04Nm= 2i cos 3 c=2 710.04 1.5 cos25.84 10003.14 3.53 43 (7.08.6) 0.47 2 19.14950.330Mpa齿轮副弯曲强度满足要求。5.2 齿轮的接触强度齿轮的接触应力计算公式: = 0.418 ( 1 + 1 )(5-2) j12式中: 齿面法向力,N; =tcos cos (5-3) 圆周力,N;= 2i(5-4)tti 计算载荷,N mm;节圆直径,mm; 节点处压力角;螺旋角;齿轮材料的弹性模量,取 2.1 105pa;齿轮接触的实际宽度,斜齿齿轮用cos 代替,mm。1,2 主、被动齿轮节点处的齿廓曲率半径,mm;直齿齿轮:1 = 1 sin ,2 = 2 sin ;斜齿齿轮:1 = 1 sin /2, 2 = 2 sin /2;1 ,2 分别为主、被动齿轮的节圆半径,mm。当计算载荷为i = 0.5emax时,许用接触应力见表 5-1。表 5-1 变速器齿轮的许用接触应力齿轮sj /Map渗碳齿轮氰化齿轮一档及倒档190020009501000常啮合及高档130014006507005.2.1 一档计算载荷为i = 0.5emax1 = 0.5 97 5.958 = 288.963Nm, 由公式(5-4)和(5-3)得:t= 2i= 2288.9631000 9713.04173.5 =tcos cos =9713 .04cos20 cos 25.84 11484.711 = 1 sin /2 = 53.5 sin 20/2225.84 11.29mm2 = 2 sin /2 = 167.2 sin 20/2225.84 35.30由公式(5-2)得: = 0.418 ( 1 + 1 ) j12= 0.41811484 .712.1105 ( 1 + 1 )27 1350.75pa11.2935.305.2.2 二档计算载荷为i = 0.5emax2 = 0.5 97 3.166 = 153.551Nm, 由公式(5-4)和(5-3)得:t= 2i= 2153.551 1000 3988.34223.5 =cos cos =3988 .34cos20 cos 25.84 4715.811 = 1 sin /2 = 85.5 sin 20/2225.84 18.05mm2 = 2 sin /2 = 124.5 sin 20/2225.84 26.28由公式(5-2)得: = 0.418 ( 1 + 1 ) j12= 0.4184715.812.1105 ( 1 + 1 )5.2.3 三档25 804.25pa18.0526.28计算载荷为i = 0.5emax3 = 0.5 97 1.863 = 90.3555Nm,由公式(5-4)和(5-3)得: = 2i = 2 90.3555 1000 1721.06t30 3.5 =cos cos =1721.06cos20 cos 25.84 2034.981 = 1 sin /2 = 116.5 sin 20/2225.84 24.60mm2 = 2 sin /2 = 97.5 sin 20/2225.84 20.58由公式(5-2)得: = 0.418 ( 1 + 1 ) j12= 0.4182034.98 2.1105 ( 1+1 )5.2.4 四档27 496.78pa24.6020.58当计算载荷为i = 0.5emax = 0.5 97 = 48.5Nm, 由公式(5-4)和(5-3)得: = 2i = 2 48.5 1000 1630.3t17 3.5 =cos cos =1630.3cos20 cos 25.84 1927.671 = 1 sin = 144 sin 20/2225.84 30.4mm2 = 2 sin = 53.5 sin 20/2225.84 11.29由公式(5-2)得: = 0.418 ( 1 + 1 ) j12= 0.4181927.67 2.1105 ( 1 + 1 )5.2.5 倒档16 731.78pa30.411.29计算载荷为i = 0.5emaxR = 0.5 97 7.32 = 355.02Nm, 由公式(5-4)和(5-3)得: = 2i = 2 355.02 1000 9221.30t22 3.5 =cos cos = 9221.30 9813.10cos201 = 1 sin = 77 sin 20/2 13.172 = 2 sin = 59.5 sin 20/2 10.18由公式(5-2)得: = 0.418 毕 业 设 计(论 文)外 文 参 考 资 料 及 译 文译文题目: Automobile Transmission Design 汽车变速器的设计 学生姓名: 学 号: 专 业: 所在学院: 指导教师: 职 称: 20xx年 2月 27日说明:要求学生结合毕业设计(论文)课题参阅一篇以上的外文资料,并翻译至少一万印刷符(或译出3千汉字)以上的译文。译文原则上要求打印(如手写,一律用400字方格稿纸书写),连同学校提供的统一封面及英文原文装订,于毕业设计(论文)工作开始后2周内完成,作为成绩考核的一部分。外文原文Automobile Transmission DesignAbstractThe topic of this project is a design of transmissions for a medium-size truck. The adoption of suitable designs and layout enables the effective utilization of engine to improve the trucks motility and economy. The design was referred to parameters of Beijing Foton truck and relevant books. Via a comprehensive demonstration, the data was collected from various components of the transmission which were modeled by Solidworks. The transmission is a five-speed transmission, including five forward gears and one reverse gear, applying advanced monolithic structure of the intermediate shaft and the shift lock ring-type synchronizer. The gearbox possesses a compact structure, a small size, high transmission efficiency, and a larger ratio range, with good economy and dynamic performance.Keywords: five-speed, intermediate shaft, synchronizer.1. IntroductionThe role of transmission:Transmission changes the speed of the engine and exports different rotational speed. At low rotational speed, high torque can be obtained. High speed has better efficiency but the torque is low. So, when you start a machine you need to start at low speed and after running then change high rotational speed maintaining a high efficiency.Specifically, in order to ensure good transmission performance, it should meet the following requirements.1) Choose the correct gear shift number and transmission gear ratios, and make the optimal matching of engine parameters to ensure that the car has good power and economy.2) Set neutral to ensure the car engine and the transmission can separate for a long time.3) Set reverse, so that the car can travel backwards.4) Set the power output apparatus.5) Shift quickly, labor-saving, easily.6) Reliable. During driving, the transmission cannot out-of-mesh, random mesh.7) Transmission should have a high efficiency.8) Transmission should be simple, smooth, no noise.2. Demonstration program2.1 Select transmission typeThere are many types of transmissions.By the number of forward gears, transmissions can be divided into three, four,five-speed and the multi-speed transmission, five speed transmission was chosen.According to the shaft of different form, transmission can be divided into fixed shaft and rotating shaft (often with planetary gear transmission) two kinds of transmissions. The main characteristic of fixed axis transmission is easy to realize automatic shift widely used. Two shaft transmission for front engine front-wheel drive. The shaft of rotation type is mainly used for hydraulic mechanical transmission. Fixed shaft type was chosen.According to the number of different shafts, the transmission can be divided into two-shaft transmission, layshaft transmission and multiple shafts transmission.2.1.1 Two-shaft transmissionIf the transmission ratio is small, we often choose two shaft types. It has the following characteristics.1. The gearbox output shaft and the main driving gear speed reducer make it an organic whole.2. When the engine is longitudinally mounted, the main reducer can use spiral bevel gear or hypoid gear, when the engine is held horizontally, it is tapped with a cylindrical gear, thereby simplifying the manufacturing process.3. The other gears adopt constant mesh gear transmission, except the reverse gear drive.4. Most of the synchronizer of gears at the end of the output shaft.5. If low gear transmission is relatively large, the size of the structure increases, it no longer has the above advantages, it can only drive relatively small conditions before using this program.6. Two-shaft transmission does not have directly gears, therefore, working at high speed, gears and bearings are bearing, gear noise, and easy to be damaged.2.1.2 Layshaft transmissionFrom a structural view, there are three shafts: the first and the second shaft are in the same line, and they are directly shifted. When using direct shift transmission, gears, bearings and the second shaft are not loading bearing. The engine torque through the first and second shaft have direct output, and the transmission has high transmission efficiency - up to 90 %. This means that it has less wear and long service life, thus, noise is also smaller. Because the efficiency of direct gear is higher than the other forward gears, it increases the life of the transmission. When the transmission power is transmitted through the first shaft (the intermediate gear shaft and the second shaft), so the distance between them is not too long, but there is still a large transmission gear ratio. High gear uses constant mesh transmission, whereas low speed gear cannot use constant mesh gear. Most transmission schemes except first speed gear shift mechanism are used in synchronization or clutch shift. Few first speed gears are also used to synchronizer type or clutch type shift. Intermediate shaft transmission is widely used in various types of rear-drive cars. That is the reason why the structure is adopted to the design. Twin intermediate shaft transmissions or multiple intermediate shaft types are the mostly used in heavy vehicles. As it does not match with the design, it is not examined further. (Yu, 2009, p.122)2.2 Gear selectionThere are two transmission gears: spur gears and helical gears. Spur gear is used for sliding. It is applied in reverse gear and the first gear specifically. The structure is simple and easy to manufacture, but when it is shifting, the root of the gear tooth is prone to bring about noise. That intensifies the wear of gears and lowers the life expectancy. And due to the noise, it easily leads into driver fatigue. Helical gears offer smooth transmission, lower noise, lower wear and longer life. The drawbacks are the axial force generated when working and the structure is complex. This drawback can be balanced when making the calculation of the shaft.By comparing the advantages and disadvantages of the two forms of the gears, reverse and the first speed gear use straight gear, which is considering following factors: the reverse gear and the first speed gear are low usage. Measuring the economy and practicality of the gear structure, the rest of the gears are helical gears, that depends on helical gear has smooth transmission and lower noise. (Yu, 2009, p.126)2.3 Shift gear structure selectionTransmission shift introduces three kinds of forms: straight teeth sliding, gear meshing and synchronizer shifting.2.3.1: Straight teeth sliding gearThis form is easy to manufacture, has a simple structure, but includes various disadvantages. It is prone to impacts due to the shift, leading to fast wearing, lower service life and higher noise. Therefore, it reduces the driving safety and comfort of a car. And technical requirements of the driver are too high, which can influence the driving of the car.2.3.2: Gear meshingUsing a meshing shift increases the number of gear teeth to receive the impact load during the gear shift. In gear meshing, the gear tooth is not involved in the shift, so it is allowing longer life cycle. However, it cannot eliminate shift impact.Therefore, the car safety and ride comfort are affected by a certain amount, and the technical requirements of the driver are too high. In addition, due to adding the mesh and mesh gear, often makes a big moment of inertia of rotating parts of the transmission, so this way of shifting generally is applied to some place without high demand and heavy lorry.2.3.3 SynchronizerThis shift form can eliminate shift shock and the rapid shift. And the manipulation is light. Also, the drivers request is not high. Eliminating noise and shift shock improves the car ride safety, acceleration, comfort and economy. So, modern cars are generally used in this form but due to its complex structure, manufacturing needs high accuracy requirement. The manufacturing of synchronizer is difficult and synchronous ring is easy to damage but it is still widely used. This design adopts this shifting form. (Yu, 2009, p.130)2.4 The form of reverse selectionIn order to achieve the reverse drive easily. Cars are equipped with a reverse idle gear between the layshaft and output shaft. This program structure is simple and easy to produce. Figure 2.1 Reverse gears (Drawing by the Solidworks).2.5 Transmission structureFigure 2.2 Transmission structure (Drawing by hand)2.6 Synchronizer selectionSynchronizer typically has normal pressure type, inertia type and self-servo type. Among them, the inertia type synchronizer is more commonly used.2.6.1 Normal pressure synchronizerThe structure of the synchronization structure is simple. Because the engagement sleeve axial resistance is caused by the spring pressure, the pressure of limited size is not guaranteed. So this form of synchronizer has been applied only on heavy vehicles. The transmission does not use this synchronizer.2.6.2 Self-servo synchronizerThe synchronizer is also known as Boshe Er synchronizer. It can ensure that only in the synchronous state shift, as long as there is the angular velocity difference between clutch and gears, the spring of synchronizer supports force to stop synchronizer ring shrinking, so it prevents movement of meshing sets.Only when the angular speed difference is zero, the spring unloads the load, due to losing the resistance of synchronous ring, shifting process can be achieved. Boshe Er synchronizer has high friction torque, simple structure, reliable operation and short axial dimension. They make transmission in trucks very convenient. 2.6.3 Inertia type synchronizerThis form of synchronizer is the same as the normal pressure type synchronizer. It depends on friction effect of synchronization. But it can ensure the joint sets and joint spline gear ring keep distance before the synchronization, and avoid the shock and noise between the teeth. From the structural term, inertia type synchronizer has lock pin type, lock ring type, slider type, chip type and cone type. Although their structures are different, they have the same friction elements, locking elements and elastic elements.1) The essence of a sliding block type synchronizer is the lock ring synchronizer. It works reliably. It has durable parts but because of the restrictions on the structure arrangement, the bending moment capacity is not big, and tooth surface wear large. So, to be on the safe side, the car does not use this kind of synchronizer.2) The locking surface of lock ring synchronizer is on the conical surface of synchronous cone ring. That eliminates the teeth of the synchronized cone ring, thus it makes the shaft size is smaller. Considering the rationality of the structural layout, compactness and cone friction torque factors. It is applied for cars and medium trucks transmissions. So this transmission adopts the lock ring synchronizer.3) The advantage of locking pin type synchronizer is that it has small number of parts, average friction cone radius is larger and torque capacity is improved. The disadvantage is that the axial size is big. So, it is usually for heavy auto transmission. The design does not use this form of synchronizer.4) The locking surface of cone type synchronizer is still on the synchronization ring joint tooth, but inserting two auxiliary synchronizations between the two cone surfaces. Since the effective area of the cone friction surfaces is exponentially increasing, the synchronizing torque is increased accordingly, thus having a large capacity and a low torque load. This will not only improve the synchronization performance, increase reliability, but also shift power is greatly reduced. If the shift force remains unchanged, the synchronization time can be shortened. Multi-cone synchronizers are used for heavy vehicles. (Liu, 1996, p.175)2.7 The transmission shaft and parts localizationThe gears and bearings of output shaft are axial positioned by the snap ring, thrust ring. The axial position of lay shaft is through the snap ring and bearing adjustment shim. Synchronizers are located by shaft shoulder and shaft collar.(Liu, 1996, p.182)Lock ring synchronizerFigure 2.3 The real lock ring synchronizer (Automotive Transmission, 2013,p.1).Figure 2.4 The simulative synchronizer (Drawing by Solidworks)Figure 2.5 The exploded view (Drawing by Solidworks)Figure 2.6 The whole view (Drawing by Solidworks)中文译文汽车变速器的设计摘要 本文主要描述一种中型货车变速器的设计,通过适当的设计和布局,有效利用发动机来提高卡车的动力性和经济性。本次设计涉及北京福田汽车的参量和相关书籍。通过一个全面的演示,用Solidworks建好模的变速器的各部件的数据都被收集。这是一个五级变速器,其中包括五个前进档和一个倒档,应用先进整体结构的中间轴和移位锁环式同步器。变速箱具有结构紧凑,体积小,传输效率高,且传动比范围大,具有良好的经济性和动态性能。关键词:五级变速,中间轴,同步器1引言变速器的作用:变速器改变发动机转速和转矩。在低转速时,能提供高转矩。高速时不仅效率更高而且转矩较低。因此,当你运行一个机器时,你需要能在低转速下启动,在运行换高转速时保持高效率。具体而言,为了保证良好的传输性能,它应该满足以下要求。1)选择正确的齿轮换档数和传动齿轮比,并且要使发动机参数的最佳匹配,以确保汽车有良好的电力和经济2)设置空档,以确保汽车发动机和变速器能分离一段时间3)设置倒档,以便汽车倒退行驶4)设置功率输出装置5)换档快,省力,方便6)可信赖。在驾驶途中,变速器不能脱档,随机啮合7)变速器具有高效率8)变速器应该简单,平滑,无噪音2演示程序2.1 选择变速器类型变速器有很多种类。根据前进档数量分,变速器可分为三级,四级,五级和综合式变速器。在这里选择五级变速器。根据不同形式的轴,变速器可分为固定轴与转轴(常与行星齿轮传动)2种变速器。固定轴变速器的主要特点是易实现自动变速,前置发动机双轴传动前轮驱动。旋转型轴主要用于液压机械传动。在这里选择固定轴式。2.1.1 双传动轴变速器如果转动比小,我们一般选择双传动轴。它有以下特征:1变速箱输出轴和主减速器构成一个有机整体;2当发动机纵向安装时,主减速器可以使用螺旋锥齿轮和准双曲面齿轮;当发动机保持水平,它是用圆柱齿轮,从而简化了制造过程;3除了反向齿轮传动,其他的齿轮采用恒定啮合齿轮传动;4大部分的同步齿轮在输出轴端;5如果齿轮传动较低,结构尺寸较大增加,它不再有上述优势,它只能驱动使用此程序前比较小的条件;6双传动轴变速器没有直接齿轮,因此,在高速下运作时,齿轮和轴承之间有轴承力,齿轮发出噪音,并且易被损坏。2.1.2 中间轴变速器从结构视图上看,有三个轴:第一根轴和第二根轴在同一直线上,它们能直接转换。当直接移位时,变速器,齿轮,轴承和二轴都没有承载轴承力。发动机转矩通过一轴二轴直接输出,变速器有着高传输效率,达至90%。这意味着它具有较少的磨损和使用寿命长,因此,噪音也较小。因为直接档的效率高于其他前进档,所以它增加了变速器的寿命。当动力传输通过第一轴(中间齿轮轴和二轴),它们之间的距离不太长,但仍有一个大的传动比。高速档用常啮合式传动,然而低速挡不能用固定啮合齿轮。大多数传输方案,除了第一变速齿轮换挡机构是在同步或离合器换挡过程中使用的。几乎没有第一变速齿轮也被用来同步型或离合器型转变。中轴传动广泛应用于各类后驱汽车。这就是为什么采用结构设计的原因。双中轴传动或多个中间轴类型主要用于重型车辆。因为它不符合设计,就未进一步研究。(Yu, 2009, p.122)2.2 齿轮的选择这里有两种传动齿轮:直齿圆柱齿轮和斜齿轮。直齿圆柱齿轮用于滑动,它专门应用于倒档和一档。结构简单,易于制造,但是当它换档时轮齿根部容易产生噪音,这加剧了齿轮的磨损,降低了寿命。并且因为这噪音,容易导致司机疲劳。斜齿轮传动平稳,噪音小,低磨损,寿命长,缺点是工作时产生的轴向力结构复杂,通过轴的计算可以弥补这一缺点。通过比较这两种齿轮的优缺点,倒档和一档用直齿轮,考虑到以下原因:倒档和一档低使用率。衡量齿轮结构的经济性和实用性,其余档位用斜齿轮,这取决于斜齿轮的传动平稳性和低噪声。(Yu, 2009, p.126)2.3 变速齿轮结构的选择变速器换档介绍三种形式:直齿滑动,齿轮啮合和同步器换档。2.3.1 直齿滑动齿轮这种类型齿轮易于制作,结构简单,但包含各种缺点。易受转向影响,导致快速磨损,使用寿命短和噪音大。因此,它降低了驾驶安全性和汽车舒适性。并且对司机技术要求太高,这影响汽车的行驶。2.3.2 齿轮啮合换档时用啮合的方式换档增加齿轮齿数来获得冲击载荷。在齿轮啮合时,轮齿不参与转换,使它能延长生命周期。但是,它不能消除换档冲击。因此,汽车安全性和乘坐舒适性受到一定程度的影响,而且对司机技术要求太高。除此之外,由于增加了啮合齿轮,往往使变速器的旋转部件有一个大的惯性矩,所以这种变速器一般适用于一些要求不高的地方和重型卡车。2.3.3 同步器这种换档方式可以消除换档冲击和实现快速换档。操作轻便,对驾驶员的要求也没那么高,消除了噪音和换档冲击,提高了汽车行驶安全性,舒适性,动力性和经济性。因此,现代汽车通常应用这种形式,但因为它的结构复杂性,制造需要高精度。虽然同步器制造难度大,同步环容易损坏,但它仍被广泛使用。本设计采用这种换档形式。(Yu,2009, p.130)2.4 倒档的选择为了实现反向驱动容易,汽车在中间轴和输出轴之间配备了一个反向空转齿轮。这个程序结构简单,易于制造。图2.1 换向齿轮机构 (Solidworks绘制)2.5 变速器结构图2.2 变速器结构 (手绘)2.6 同步器的选择同步器类型有常压式,惯性式和自伺服式。在这之中,惯性式同步器比较常用。2.6.1 常压式同步器这种同步器结构简单,由于弹簧压力引起的啮合套筒轴向阻力,这限制的压力大小是不保证的。因此,这种形式的同步器仅仅适用于重型车辆。变速器不使用这种同步器。2.6.2 自伺服式同步器同步器也称为博舍ER同步。它可以确保只有在同步状态转移,只要在离合器和齿轮之间有角速度差,同步器的弹簧支撑力使同步环停止收缩,所以它可以防止啮合套运动。只有当角速度差为零时,弹簧卸负荷,由于失去了同步环的阻力,换档过程可以实现。博舍ER同步器具有高摩擦力矩,结构简单,操作可靠性和轴向尺寸短。它们使变速器在卡车里的应用十分方便。2.6.3 惯性式同步器惯性式同步器结构与常压式结构一样,取决于同步的摩擦效应。但它可以确保接合套和接头花键齿圈在同步保持距离,避免轮齿之间发生碰撞和噪音。从结构来看,惯性式同步器有锁销式、锁环式、滑动式、片式和锥式。尽管它们的结构各有不同,但它们有同样的摩擦元件,锁定元件和弹性元件。1)一个滑块式同步器的本质是锁圈同步器。它工作可靠,具有耐久性,但由于结构布置的限制,弯矩能力不大,且齿面磨损较大。因此,为了安全起见,汽车不使用这种同步器。2)锁环式同步器的锁面是在同步锥环的锥面上。这消除了同步锥环的齿,从而使轴的尺寸较小。考虑结构布置的合理性,紧凑性和锥形摩擦力矩的影响因素,锁环式同步器应用于汽车和中型卡车变速器。因此本次变速器采用锁环式同步器。3)锁销式同步器的优点是零件数量少,平均摩擦锥半径较大,扭矩能力提高,缺点是轴的尺寸较大。因此,锁销式同步器通常用于重型汽车变速器。本设计不用这种结构的同步器。4)锥式同步器的锁面仍在同步环齿里,但在两锥表面插入两个辅助同步。由于锥形摩擦表面的有效面积是成倍增加,同步转矩相应增加,从而具有大容量和低转矩负载。这不仅提高了同步性能,提高了可靠性,而且大大降低了换挡阻力。如果换档阻力保持不变,可以缩短同步时间。多锥同步器用于重型车辆。(Liu, 1996, p.175)2.7 传动轴及零件定位输出轴的齿轮和轴承通过卡环和推力环轴向定位。中间轴的轴向位置是通过卡环与轴承调整垫片。同步器通过轴肩和轴领定位。(liu,1996,p.182)锁环式同步器(Lock ring synchronizer)图2.3 真正锁环式同步器 (自动变速器,2013,p.1)图2.4 模拟同步器 (Solidworks绘制)图2.5 剖视图 (Solidworks绘制)图2.6 全视图 (Solidworks绘制)
收藏