机械毕业设计英文外文翻译549载货汽车主减速器

附 录

Truck Main Reduction Gear

In the highly competitive period following the energy crisis of the early 1970's, the automotive industry had to shift attention increasingly towards improvement of the quality of the product, yet still keeping its prices as low as possible. Prior to that GKN Axles Ltd, to take optimum advantage of economies of scale, had been producing at highly competitive prices a standard range of axles of different types and sizes, from which all customers' needs could be satisfied. Because vehicle manufacturers had not hitherto had to place such a great emphasis on fuel economy, and therefore on light weight, these standard axles could cater reliably for all conditions likely to be met in a wide variety of applications. Now vehicle manufacturers require axles designed and developed for their specific applications. As axle design is becoming increasingly specialised, customers are increasingly raising their aspirations in terms of performance an reliability. For this reason, they are turning to specialists such as GKN Axles Ltd who have the ability to provide axles for a wide variety of vehicles。

Since the 1970s, however, in common with virtually all other suppliers to the high volume producers in the motor industry, GKN has

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radically modified its approach to suit the prevailing conditions as they change through the 1980s and on into the 1990s. Its aim now is at supplying complete axle assembles, including, for example, the brakes, all designed and fully developed for and integrated, as a matter of course, into specific vehicle designs including, in particular, those for the specialist market.

Emphasis is now on rationalization of materials, methods and components. This overall change has been necessary because of the greatly in creased sophistication demanded of the modern vehicle, in terms of overall efficiency, compactness, light weight, reliability, durability, refinement and maintenance-free operation. Another area into which GKN Axles has expanded is the supply of components and assemblies such as limited-slip differentials, ball-joints, transfer boxes, gears and some types of suspension.

For off-road operation, the duty cycles may be entirely different in both torsional and beam loading-denpending on the application. For example, some types of vehicle spend a considerable proportion of their running time at high torque in low gear. In most circumstances, the terrain may be such that the tyres tend to slip more readily than on tarmac; in others, however, for example in fairly firm sandy screes, it may allow tyres to bite into it, and thus lead to torsional fatigue loading significantly greater than on smooth roads. Vertical and lateral loading,

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too, may be much more severe, though this dose depend to a major extent on speeds. Shock loading can also affect braking and acceleration torques though, again, such effects are speed-dependent.

Hypoid gear systems are more commonly used than spiral bevels. Their principle advantages are that pinions of a specific ratio are bigger, their teeth profiles are of large radius, they are inherently stronger and more durable, their meshing areas are larger, and they generate less noise

Host reduction gear effect is to be used to reduce the rotation rate that the transmission shaft sends in but to enhance revolution moment of torsion , changes drive direction with moment of torsion , passes on to half axes after differential mechanism and. The host reduction gear structure form is that the form is different but different according to gear wheel type , reduction gear mainly. Host reduction gear gear wheel has helix cone forms such as gear wheel , hypoid gear , column gear wheel and worm gear worm mainly.

Pair of level host reduction gear is compared with single stage , the gap may be 7 ~12 transmission ratio , i0 each other at the same time in swear to be away from a field 12. But the dimension , mass are without exception bigger , cost is higher. It applies to middle, heavy type freight train , go-anywhere vehicle and motor bus mainly go ahead.

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Dyadic overall pair of level host reduction gear has the various structure scheme: First order is a cone gear wheel , the second stage is a column gear wheel; First order is a cone gear wheel , the second stage is epicyclic gear; First order is epicyclic gear , the second stage is a cone gear wheel; First order is a column gear wheel , the second stage is a cone gear wheel.

Horizontal , askew, face and droop over to the three kinds to first order for the cone gear wheel , the second stage are that pair of column gear wheel level betokens reduction gear, but has direction arrangement scheme.

Direction level arrangement can use the assembly drooping over to outline dimension diminution , reducing the automobile quality heart altitude thereby, makes the direction dimension increase by but , that the use on long distance between shafts automobile but appropriate diminution transmission shaft length, is harmful for short distance between shafts automobile's to put arrangement together but, may make a transmission shaft short , leads to a universal transmission shaft intersection angle enlarge. Droop over to arranging a messenger to drive the bridge direction dimension diminution, may diminish a universal transmission shaft intersection angle, since but host reduction gear shell fixes superjacent in bridge shell , make not only droop over enhance to outline dimension, and have reduced bridge shell stiffness , have been

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harmful for gear wheel to work. This arrangement but easy to be versed in style driving a bridge arrangement. Arranging bridge shell stiffness and improving to the transmission shaft is slanting to arrangement advantageous.

When assigning a transmission ratio in pair of level host reduction gear having the cone gear wheel and the column gear wheel, the column gear wheel is 1.4 ~ like the ratio auxiliary and boring subsidiary gear wheel transmission ratio 2.0, and the cone gear wheel is 1.7 ~ like subsidiary transmission ratio 3.3, such axial loading may diminish a cone when the gear wheel is engaged and effect loading on the driven cone gear wheel and the column gear wheel, may make the active cone gear wheel tooth number appropriate increasing by at the same time , make whose supporting axis neck dimension appropriate enlarge, To improve whose supporting stiffness, improve falling-in stationarity and the job reliability.

For modern axles, choice of gear lubricant can be critical. In cars operating at high speeds on motorways, axle oil temperature can ultimately rise even higher than 130℃,so venting of the casing is important. In principle, the oil in the base of the casting is swept around over the crownwheel and then forwards through the two bearings that carry the pinion. Consequently, both the shapes and dimensions of the clearances between the crownwheel and casing can be critical, and

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adequate drainage has to be provided for the oil to flow, through channels cored in the pinion bearing housings, back to the base of the casing.

Within the gear carrier unit, taper roller bearings are employed almost universally for carrying the input pinion. They have a large load capacity within a small envelope, and can be preloaded for accurate and stable positioning of the gears. For pinion flange seals where resistance to high temperatures at relatively high speeds is essential, polyarcylate may be specified, but the abrasive conditions Viton is generally preferred.

That the cone gear wheel tooth goes over width face to face can not enhance gear wheel intensity and life-span , is able to lead to tooth ditch unexpected turn of events small end because of cone gear wheel gear teeth on the contrary narrow the cutting knife the top of the head face width arousing is too narrow and the point of a knife round angle is too small. Like this , not only, have diminished the tooth radical circle radius , have enlarged strain all together, life time having reduced a cutter. Besides , when assembling, have location deviation or wait for cause since fabrication , heat treatment are deformable, loading concentrates minor in gear teeth end when making a gear wheel work , is able to arouse gear teeth holding untimely damage and weary loss for a short time. That besides, the tooth goes over width face to face also is able to

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arouse assembling space diminution. The flank of a tooth is too narrow but , the gear teeth outside abrasion resistance meeting reduces.

For the running-in improving the new gear wheel, prevent the person from dying in working to Model T wear appear on initial stage , bruising , gluing together or barking, cone gear wheel bonderizing being 0.005 ~ 0.020 mm in heat treatment and finish machining aftercrop, thickness handles or the copper facing , the tin plating handle. The ball carrying out strain on the flank of a tooth gushing is sold at reduced prices , may improve 25%'s gear wheel life-span. To the high speed gear wheel sliding, may be in progress a sulfur oozing handling to improve abrasion resistance. Rub a factor but notable sulfur queen lessening oozes, even if lubricating condition is relatively poor , also, can prevent the flank of a tooth bruise from facing , barks to die and glue together.

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载货汽车主减速器

在能源竞争激烈的二十世纪七十年代初，汽车业不得不将注意力越来越多地定格在改进产品的质量上，但仍然维持其价格尽可能低。在此之前，吉凯恩车桥有限公司占据最佳经济规模的优势，在价格允许范围内生产极具竞争力的不同类型车轴，使所有客户的需求可以得到满足。但由于汽车制造商并没有经历过这样一个非常注重燃油经济性的时期，因此，对重量轻的要求，这些标准车轴似乎可满足所有条件，满足各种各样的应用。现在汽车制造商需要车轴设计和开发的具体应用。轴设计正变得越来越专业化，在性能的可靠性方面，客户越来越多地提高自己的期望。出于这个原因，他们在找一个能提供各种

车辆轴的公司。

然而自二十世纪七十年代以来，在几乎所有其他汽车行业供应商的技术里， GKN从根本上改变了它的办法，以适应当前的条件，他们在二十世纪八十年代和九十年代的生产目的是提供完整的轮轴安装，其中包括，刹车、所有的设计和整合、具体的汽车设计，以及为专业市场特别设计的。

现在的重点是合理化的材料，方法和内容。总的改革是必要的，对于复杂性很大的现代汽车，考虑总体效率，紧凑，重量轻，可靠性，耐用性，完善和免维护运行。另一个领域，GKN提供的车轴是扩大了供应的部件和组件，如限滑差速器，球关节，齿轮和某些类型的悬挂架。

对于越野车，某些车辆设计公司花费了相当多的时间在较低齿轮但高扭矩的设计上。在大多数情况下，地形可能使这样的轮胎打滑。

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例如，在相当坚硬的沙质路面，它可能允许轮胎咬进去，从而使扭转疲劳显著大于在平稳的道路行驶。虽然在大程度上这取决于速度，但纵向和横向打滑时将更严重。冲击负荷也会影响刹车和加速扭矩，这种影响是取决于速度的。

准双曲面齿轮传动是锥齿轮传动中的普遍形式，螺旋锥齿轮是它的一种特殊情况。他们的优点是齿轮的具体比例较大，其啮合区较大，而且低噪音,他们本质上是更强大，更持久和更耐用。

主减速器的作用是用来降低传动轴传来的转速而增大旋转扭矩，并将扭矩改变传动方向，经差速器传给半轴。主减速器的结构形式主要是根据齿轮类型、减速器形式不同而不同。主减速器的齿轮主要有螺旋锥齿轮、双曲面齿轮、圆柱齿轮和蜗轮蜗杆等形式。

双级主减速器与单级相比，在保证离地间隙相同时可得到大的传动比，i0一般为7～12。但是尺寸、质量均较大，成本较高。它主要应用于中、重型货车、越野车和大客车上。

整体式双级主减速器有多种结构方案：第一级为锥齿轮，第二级为圆柱齿轮；第一级为锥齿轮，第二级为行星齿轮；第一级为行星齿轮，第二级为锥齿轮；第一级为圆柱齿轮，第二级为锥齿轮。

对于第一级为锥齿轮、第二级为圆柱齿轮的双级主减速器，可有纵向水平、斜向和垂向三种布置方案。

纵向水平布置可以使总成的垂向轮廓尺寸减小，从而降低汽车的质心高度，但使纵向尺寸增加，用在长轴距汽车上可适当减小传动轴长度，但不利于短轴距汽车的总布置，会使传动轴过短，导致万向传

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动轴夹角加大。垂向布置使驱动桥纵向尺寸减小，可减小万向传动轴夹角，但由于主减速器壳固定在桥壳的上方，不仅使垂向轮廓尺寸增大，而且降低了桥壳刚度，不利于齿轮工作。这种布置可便于贯通式驱动桥的布置。斜向布置对传动轴布置和提高桥壳刚度有利。

在具有锥齿轮和圆柱齿轮的双级主减速器中分配传动比时，圆柱齿轮副和锥齿轮副传动比的比值一般为1.4～2.0，而且锥齿轮副传动比一般为1.7～3.3，这样可减小锥齿轮啮合时的轴向载荷和作用在从动锥齿轮及圆柱齿轮上的载荷，同时可使主动锥齿轮的齿数适当增多，使其支承轴颈的尺寸适当加大，以改善其支承刚度，提高啮合平稳性和工作可靠性。

现代车桥中，齿轮润滑油的选择是至关重要的。汽车运行在高速公路上，车桥油温可以最终上升，甚至高于130℃ ，所以车桥外壳通风是很重要的。通过两个轴承携带的小齿轮来达到改善的目的。因此，形状和尺寸之间的间隙，套管等可能都是至关重要的，足够的排水必须提供的润滑油的流向，通过渠道流入小齿轮轴承座，再回到套管。

在齿轮轴承中，圆锥滚子轴承普遍应用在齿轮。他们有大量的承载能力，通过稳定的、准确定位。法兰密封的齿轮对于抗高温和相对较高的速度是至关重要的。

锥齿轮齿面过宽并不能增大齿轮的强度和寿命，反而会导致因锥齿轮轮齿小端齿沟变窄引起的切削刀头顶面宽过窄及刀尖圆角过小。这样，不但减小了齿根圆半径，加大了应力集中，还降低了刀具的使

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用寿命。此外，在安装时有位置偏差或由于制造、热处理变形等原因，使齿轮工作时载荷集中于轮齿小端，会引起轮齿小端过早损坏和疲劳损伤。另外，齿面过宽也会引起装配空间的减小。但是齿面过窄，轮齿表面的耐磨性会降低。

为改善新齿轮的磨合，防止其在运行初期出现早期的磨损、擦伤、胶合或咬死，锥齿轮在热处理及精加工后，作厚度为0.005～0.020mm的磷化处理或镀铜、镀锡处理。对齿面进行应力喷丸处理，可提高25％的齿轮寿命。对于滑动速度高的齿轮，可进行渗硫处理以提高耐磨性。渗硫后摩擦因数可显著降低，即使润滑条件较差，也能防止齿面擦伤、咬死和胶合。

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用寿命。此外，在安装时有位置偏差或由于制造、热处理变形等原因，使齿轮工作时载荷集中于轮齿小端，会引起轮齿小端过早损坏和疲劳损伤。另外，齿面过宽也会引起装配空间的减小。但是齿面过窄，轮齿表面的耐磨性会降低。

为改善新齿轮的磨合，防止其在运行初期出现早期的磨损、擦伤、胶合或咬死，锥齿轮在热处理及精加工后，作厚度为0.005～0.020mm的磷化处理或镀铜、镀锡处理。对齿面进行应力喷丸处理，可提高25％的齿轮寿命。对于滑动速度高的齿轮，可进行渗硫处理以提高耐磨性。渗硫后摩擦因数可显著降低，即使润滑条件较差，也能防止齿面擦伤、咬死和胶合。

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