传动轴基本知识

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1、传动轴基本知识一、 传动轴总成简介（结合具体总成图）传动轴，英文PROPELLER （DRIVING） SHAFT。在不同轴心的两轴间甚至在 工作过程中相对位置不断变化的两轴间传递动力。传动轴按其重要部件万向节的不同，可有不同的分类。如果按万向节在 扭转的方向是否有明显的弹性可分为刚性万向节传动轴和挠性万向节传动轴。前 者是靠零件的铰链式联接传递动力的，后者则靠弹性零件传递动力，并具有缓冲 减振作用。刚性万向节又可分为不等速万向节（如十字轴式万向节）、准等速万 向节（如双联式万向节、三销轴式万向节）和等速万向节（如球笼式万向节、球 叉式万向节）。等速与不等速，是指从动轴在随着主动轴转动时，两者

2、的转动角 速率是否相等而言的，当然，主动轴和从动轴的平均转速是相等的。主、从动轴的角速度在两轴之间的夹角变动时仍然相等的万向节，称为等速 万向节或等角速万向节。它们主要用于转向驱动桥、断开式驱动桥等的车轮传动 装置中，主要用于轿车中的动力传递。当轿车为后轮驱动时，常采用十字轴式万 向节传动轴，对部分高档轿车，也有采用等速球头的；当轿车为前轮驱动时，则 常采用等速万向节等速万向节也是一种传动轴，只是称谓不同而已。在发动机前置后轮驱动（或全轮驱动）的汽车上，由于汽车在运动过程中悬 架变形，驱动轴主减速器输入轴与变速器（或分动箱）输出轴间经常有相对运动， 此外，为有效避开某些机构或装置（无法实现直线

3、传递），必须有一种装置来实 现动力的正常传递，于是就出现了万向节传动。万向节传动必须具备以下特点： a 、保证所连接两轴的相对位置在预计范围内变动时，能可靠地传递动力； b 、保证所连接两轴能均匀运转。由于万向节夹角而产生的附加载荷、振动和噪 声应在允许范围内；c、传动效率要高，使用寿命长，结构简单，制造方便，维修容易。对汽车而言，由于一个十字轴万向节的输出轴相对于输入轴（有一定 的夹角）是不等速旋转的，为此必须采用双万向节（或多万向节）传动，并把同 传动轴相连的两个万向节叉布置在同一平面，且使两万向节的夹角相等。这一点 是十分重要的。在设计时应尽量减小万向节的夹角。传动轴总成不平衡是传动系弯

4、曲振动的主要原因。其引起的振动噪声是明显 的。此外，万向节十字轴的轴向窜动、传动轴滑动花键中的间隙、传动轴总成两 端连接处的定心精度、高速回转时传动轴的弹性变形及传动轴上点焊平衡片时的 热影响因素等都能改变传动轴总成的不平衡度。降低传动轴的不平衡度，对于汽 车，尤其是高速汽车如（轿车）是极其重要的，否则会引起很多相关故障或异常 损坏。十字轴式刚性万向节传动轴在汽车传动系中用得最广泛，历史也最悠久。平 时所说的传动轴一般指的就是十字轴式刚性万向节传动轴。十字轴式刚性万向节 主要用于传递角度的变化，一般由突缘叉、十字轴带滚针轴承总成、万向节叉或 滑动叉、中间连接叉或花键轴叉、滚针轴承的轴向固定件等

5、组成。突缘叉一般与 变速箱、驱动桥或别的传动轴等连接。突缘叉是一个带法兰的叉形零件，一般采 用中碳钢或中碳合金钢的锻造件，也有采用球墨铸铁的砂型铸造件和中碳钢或中 碳优质合金钢的精密铸造件。突缘叉一般带一个平法兰，也有带一个端面梯形齿 法兰的。十字轴带滚针轴承总成一般包括四个滚针轴承、一个十字轴、一个滑脂 嘴。滚针轴承一般由若干个滚针、一个轴承碗、一个多刃口橡胶油封（部分带骨 架）组成。在某些滚针轴承中，还有一个带油槽的圆形垫片，有尼龙的，也有采 用铜片或其他材料的，主要用于减小万向节轴向间隙，提高传动轴动平衡品质。 万向节叉是一个叉形零件，一般采用中碳钢或中碳合金钢的锻造件，也有采用中 碳钢

6、的精密铸造件。滚针轴承的轴向固定件一般是孔（或轴）用弹性挡圈（内外 卡式），或轴承压板、锁片、螺栓等。传动轴的另外一个重要的组成部分是滑动花键副，由内、外花键（矩形、渐 开线）组成，用于传递长度的变化。传动轴的万向节摆角和滑动花键副的最大伸缩量，是根据整车布置时进行的 传动轴跳动校核而确定的。传动轴管一般由低碳钢板卷制的电焊钢管制成，对大规格的轴管，也有采用 冷拔无缝管的。轴管的外径和壁厚（或内径）是根据传动轴所传递的最大工作扭 矩、最高工作转速等条件确定的。空心的轴管具有较小的质量并能传递较大的扭 矩，并且比相同外径的实心轴具有更高的临界转速的特点。一般情况下，两万向节中心距不大于1.5m。

7、当距离较近时，一般由两个万向节和一个滑动花键副组成，中间无轴管。当距离较远而使传动轴的长度超过1.5m 时，常常分成两根或三根，采用三个或四个万向节，且最后一根带滑动花 键副，其余的带中间支承的结构型式。典型的中间支承一般由一个圆柱球轴承、一个轴承座、两个油封、一个橡胶 垫、一个滑脂嘴组成。中间传动轴由中间支承支架连接到车架横梁上，要求中间 传动轴轴心线与中间支承平面垂直。一般要求传动轴中间支承布置在传动轴系统 的一阶临界转速节点上。在使用过程中，一般需要按时保养。在万向节、滑动花键副、中间支承等有 滑脂嘴的地方，要按有关规定进行定期加注规定的润滑脂。也有采用免维护的传 动轴，在万向节和中间支

8、承的轴承内有预留的润滑脂，不需要定期加注润滑脂。二、万向节简介万向节是汽车传动轴上的关键部件。在前置发动机后轮驱动的车辆上，万向 节传动轴安装在变速器输出轴与驱动桥主减速器输入轴之间；而前置发动机前轮 驱动的车辆省略了传动轴，万向节安装在既负责驱动又负责转向的前桥半轴与车 轮之间。汽车是一个运动的物体。在后驱动汽车上，发动机、离合器与变速器作为一 个整体安装在车架上，而驱动桥通过弹性悬挂与车架连接，两者之间有一个距离， 需要进行连接。汽车运行中路面不平产生跳动，负荷变化或者两个总成安装位置 差异，都会使得变速器输出轴与驱动桥主减速器输入轴之间的夹角和距离发生变 化，因此要用一个“以变应变”的装

9、置来解决这一个问题，因此就有了万向节。另外在越野车变速器与分动器之间，前驱动的可转向驱动桥与半轴之间，都 需要这个万向节做“关节”。万向节的结构和作用有点象人体四肢上的关节，它 允许被连接的零件之间的夹角变化。但它与肢体关节的活动形式又有所不同，它 仅允许夹角在一定范围内变化。万向节有十字轴式刚性万向节，准等速万向节（双联轴式和三销轴式），等 速万向节（球叉式和球笼式），扰性万向节。目前后驱动汽车上应用最广的一种 是十字轴万向节。单个的万向节不能使输出轴与轴入轴的瞬时角速度相等，容易造成振动，加 剧机件的损坏，产生很大的噪音。因此，后驱动汽车的万向节传动形式都采用双 万向节，就是传动轴两端各有

10、一个万向节，其作用是使传动轴两端的夹角相等， 保证输出轴与轴入轴的瞬时角速度始终相等。为了满足动力传递、转向和汽车运行时所产生的上下跳动所造成的角度变 化，前驱动汽车的驱动桥，半轴与轮轴之间也常用万向节相连。由于受轴向尺寸 的限制，要求偏角又比较大，普通万向节难以胜任，所以广泛采用各式各样的等 速万向节。在一般前驱动汽车上，每个半轴用两个等速万向节，靠近变速驱动桥 的万向节是半轴内侧万向节，靠近车轴的是半轴外侧万向节。在各种等速万向节 中，常见是球笼式万向节，它用六个钢球传力，主动轴与从动轴在任何交角的情况下，钢球都位于两园的交点上，即位于两轴交角的平分面上，从而保证主、从 动轴等角速度传动。

11、Installation conditionsWhile rotating, the universal joint has a sinuslike, fluctuating angular speed depending on the deflection an gle. As described in detail i n the chapter ”Ge neral fun dame ntal theory, this system-l in ked fault can be offset for a driving line equipped with two or more joint

12、s by choosing special joint arrangements.When dimensioning the drive or the auxlliarv drive, the following rules must be observed in practice:An gle con diti ons of the uni versal shaft1. Shaft with two join tsZ-arra ngeme ntW-arra ngeme ntThe deflecti on an gles of the joints must be equal:1= 2This

13、 rule is also applicable to front view and top view pictures.7 The joint yokes of the conn ect ing shaft must be in one pla ne. All three shafts must be in one plane.Note: All these three rules must be observed simulta neously.A joi nt arra ngeme nt in two pla nes must be avoided if possible. lt is

14、always give n whe n the driv ing and driven shafts are not in the same plane. If this arrangement is unavoidable and rigid on the installation side, this ”fault can be kin ematically compe nsated by a joint misalig nment.Fro nt view:(V1 二已Top view:二 h2For the result ing deflecti on an gles the follo

15、w ing equati ons are applicable:B如=arc tan VtoPvi 十 ten军时pres? - arc tan x/try2 + tan23h22. Shaft with three jointsIn cases where greater distances between units have to be bridged, the universal shaft must be supported by an additi on al, mostly elastic, bear ing.Jciint 3 9In order to keep the rema

16、 ining irregularity in the drive (joint 3) as small as possible, the sum of all irregula nties of the in dividualjo ints must be equal to or almost equal to zero.2U U； U3 0(See Ki nematics of Hookes joi nts)1. The jointsIn the theory of mecha nics the carda n joint or Hookes joint is defi ned as a s

17、patial or spherical drive unit with a non-uniform gear ratio or transmission. The transmission behaviour of this joint is described by the equati on.tanIn this equation 2the momentary rotation angle of the driven shaft 2. The motion behaviour of the driving and the drive n ends is show n in the foll

18、owi ng diagram. The asyn chrono us a nd / or non-homok in ematic running of the shaft 2 is shown in the periodical oscilation of the asynchronous line round the synchronous line 8(dotted line).A measure for the non-uniformity is the difference of the rotation angles and Bor the transmission ratio of

19、 the an gular speedsa nd X(also called gimbal error)跟吨班3 （貧翳）b) Gear ratio00501 _ 1 - sfnp costala) rotati on an gle differe neeExpressed by an equati on, that means:The follow ing diagram shows the gearratio i = 2/ for a full revolution of the universal joint for B = 60.The degree of non-un iformit

20、y U is defi ned by:U = i max. - i min. = tan B * sin Bwhere:U = I max.1 mm. - tanp - ?inpi max.=1C0S|1i min. = cosBDeflexion angle E二 AHULUECH-UauctQ卩The diagram shows the course of the degree of nonuniformity U and of the angular differenee 尬巾鹽as a funetion of the defleetion angle of the joint from

21、 0 to 45From the motion equation it is evident that a homokinematic motion behaviour corresponding to the dotted line under 45- as shown in the diagram - can only be obtained for the defleetion angle B= 0. A syn chr onous or homok in ematic running can be achieved by a suitable comb in ati on or con

22、n ecti on of two or more joi nts.2. The universal shaftThe rotation angle differenee 滋or the gimbal error of a deflected universal joint can be offset under certa in in stallati on eon diti ons with a sec ond uni versal joi nt. The eon structive soluti ons are the followi ng: 1) The defleeti on an g

23、les of both joints must be equal, i.e.Two arra ngeme nts are possible:1 a)2) The two joints must have a kin ematic an gular relati on ship of 90(H / 2), i.e. the yokes of the conn ect ing shaft are in one pla ne.For a more intensive study of universal shaft kinematics we refer you to the VDI-recomme

24、ndation 2722 to the relevant technical literature and especially to the book ,Kardangelenkgetriebe und ihre Anwendung (Cardan joint drives and their application) by Florian Duditza, published by VDI.The sig ns must be en tered accord ing to the followi ng sig n rule. Here the sig n rule is:for the j

25、oint positi onfor the joint positi onThe remaining non-uniformity if any should not be greater than:2U 50 1-oa 4.50 S&x 51QQQ10001500POOO25&3CHJ0 Op&iting length 丄日tnrnjDuri ng operati on the uni versal shaft can be expa nded up to this len gth. The optimum working length LB of a universal shaft is

26、achieved if the length compensation is extracted by on e-third of its len gth.Lb = Lf + JL, |mmMaintenanceMaintenance work on carda n shafts used in vehicles and in dustrial equipme nt must be done at regular in tervals.The scope and the in tervals of maintenance work depe nd on the in dividual oper

27、ati ng con diti ons of the vehicle or the equipme nt.Maintenance intervals for cardan shafts in commercial vehiclesDepe nding on the type of vehicle, the mileage or the service life and the operat ing con diti ons two differe nt scopes and in tervals of maintenance are required. These are theminor i

28、nspection and the major inspection.Use of vehicleInspection intervalsMinor inspectionMajor inspectionCommercial vehiclesin lon g-dista nee traffic or similarly used vehiclesEvery 100.000 kmorafter 1 year max.Every 500.000 kmorafter 5 years max.Commercial vehiclesused on road and off road and in city

29、 traffic and similarEvery 50.000 kmorafter 1 year max.Every 300.000 kmorafter 5 years max.Busesin lon g-dista nee trafficEvery 100.000 kmorafter 1 year max.Every 300.000 kmorafter 3 years max.Busesin city trafficEvery 50.000 kmorafter 6 monthsmax.Every 200.000 kmorafter 2 years max.Commercial vehicl

30、esused on sites, com munal vehicles, con structi on mach in es, cra nes, vehicles used in agriculture and forestry, tractors, military vehicles and similarEvery 25.000 kmorafter 6 monthsmax.Every 100.000 kmorafter 2 years max.After a cha nge of the vehicle owner or in case of an accide nt we recomme

31、 nd a major inspection of the carda n shaft.Scope of maintenanceMinor inspectionThe minor in specti on in cludes check ing the carda n shaft in stalled in a vehicle or in an in dustrial pla nt. Check the bolts of the flanges and of the centre bearing bracket for tightness (e.g. undamaged paint coat)

32、. If n ecessary, retighte n the bolts with a suitable torque wre nch and the torques prescribed by the manu facturer of the vehicle or equipme nt. Check whether there are snap rings on all bearing bushes. Check whether balanee weights are loose or missing. Check the bottoms of the bearing bushes for

33、 change of colour or form due to excessive heat. Visual in specti on of the seals of bear ing bushes and the len gth compe nsati on. Defective seals may result in excessive grease loss and breakdow n of the carda n shaft. Check whether there are grease n ipples on the jour nal crosses and whether th

34、ey are in good con diti on (excepti on: maintenan ce-free joi nts). Check whether the rilsan coat on the sleeve is damaged or shows abrasion. Visual inspection of the centre bearings of drive lines with regard to:-correct positi on of the rubber cushi on in the cen tre bear ing bracket -correct posi

35、tion of the flange shaftOuter flingerFlangeRubbei* euihifinCentre bollCentre bearing bracketIf the dista nee betwee n the rubber cushi on and the outer fli nger is too large, the cen tre bolt may work loose. In this case a check should be made as a part of a major in specti on.0 Carry out a visual i

36、nspection for possible damage, e.g.:-damaged paint coat-deformed tubes-ecce ntricity of the len gth compe nsati on cover tube-cracks on comp onents and tube Check the joints and the len gth compe nsati on for visible or tan gible backlash.If the inspection shows that the cardan shaft is damaged, it

37、must be removed at once and sent to a repair shop that is authorized either by us or by the manufacturer of the vehicle or the equipment.Furthermore, the vehicle or the equipment must be immediately taken out of operation in the case of any extraordinary noise, vibration or otherwise abnormal behavi

38、our. Before recommissioning the cardan shaft it must be checked within the scope of a minor inspection.Major inspectionEach major in specti on in cludes the scope of check ing prescribed for a minor in specti on. In additi on, the carda n shaft must be removed from the vehicle or the equipme nt for

39、the major in specti on.The follow ing check ing or work must be carried out on the carda n shaft: Checking the joint bearings-Check the two flange yokes for tangible backlash or resistance (e.g. hooking) by deflecting them by hand into vertical and horiz on tal positi ons (sw ing them to and fro).-G

40、rease the cross assemblies through the grease nipples and check whether the grease escapes from the seals. If no grease escapes from one or more bearing bushes of a cross assembly or if grease escapes together with water, rust or dirt, the carda n shaft must be sent to an authorized shop for repair.

41、If the joints are in proper condition, regrease them through the grease nipples until the grease escapes from the seals. Checking the length compensation componentsThe in volute spli ne is cen tred and guided on the spli ne outer dia. This desig n allows a maximum backlash of 0,2 mm. The radial back

42、lash n eed not be checked.-Extend the cardan shaft by approx. 45 mm and place the lugs of the inner yokes at points A and B on a solid support (see illustrati on).CFix the dial gauge holder at point C n ext to the weld on the tube and place the dial gauge directly next to the weld of the protective

43、sleeve (cover tube). Lift the cardan shaft at its center of gravity so that the supports at points A and B become free.Read axial backlash on the dial gauge.The max. permissible value is 0,17 mm.-Visual checking of the parts:Exte nd the carda n shaft completely and check the len gth compe nsati on f

44、or damage to the in side and outside areas of the spli ne muff and the teeth of the yoke shaft.-Check the seal of the cover tube for damage.If the len gth compe nsati on is un damaged:-regrease the parts of the length compensation in the sealing area (for grease see Lubrication) and br ing the len g

45、th compe nsati on together to its orig in al le ngth.Attention:Make sure that the marking arrows are opposite one another! Check the centre bearing of drive lines with regard to:-damage to the rubber cushi on-firm seat of the ball beari ng in the rubber cushi onRetighten the central bolt with a torque of 350 Nm.Attention:Cen tre beari ngs of older desig ns with a cen tral nut or hol