載貨汽車雙級主減速器設(shè)計
載貨汽車雙級主減速器設(shè)計,載貨汽車雙級主減速器設(shè)計,載貨,汽車,雙級主,減速器,設(shè)計
附 錄
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 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, 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.
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 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 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 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.
載貨汽車主減速器
在能源競爭激烈的二十世紀七十年代初，汽車業(yè)不得不將注意力越來越多地定格在改進產(chǎn)品的質(zhì)量上，但仍然維持其價格盡可能低。在此之前，吉凱恩車橋有限公司占據(jù)最佳經(jīng)濟規(guī)模的優(yōu)勢，在價格允許范圍內(nèi)生產(chǎn)極具競爭力的不同類型車軸，使所有客戶的需求可以得到滿足。但由于汽車制造商并沒有經(jīng)歷過這樣一個非常注重燃油經(jīng)濟性的時期，因此，對重量輕的要求，這些標準車軸似乎可滿足所有條件，滿足各種各樣的應(yīng)用?，F(xiàn)在汽車制造商需要車軸設(shè)計和開發(fā)的具體應(yīng)用。軸設(shè)計正變得越來越專業(yè)化，在性能的可靠性方面，客戶越來越多地提高自己的期望。出于這個原因，他們在找一個能提供各種車輛軸的公司。
然而自二十世紀七十年代以來，在幾乎所有其他汽車行業(yè)供應(yīng)商的技術(shù)里， GKN從根本上改變了它的辦法，以適應(yīng)當前的條件，他們在二十世紀八十年代和九十年代的生產(chǎn)目的是提供完整的輪軸安裝，其中包括，剎車、所有的設(shè)計和整合、具體的汽車設(shè)計，以及為專業(yè)市場特別設(shè)計的。
?? 現(xiàn)在的重點是合理化的材料，方法和內(nèi)容?？偟母母锸潜匾模瑢τ趶?fù)雜性很大的現(xiàn)代汽車，考慮總體效率，緊湊，重量輕，可靠性，耐用性，完善和免維護運行。另一個領(lǐng)域，GKN提供的車軸是擴大了供應(yīng)的部件和組件，如限滑差速器，球關(guān)節(jié)，齒輪和某些類型的懸掛架。
? 對于越野車，某些車輛設(shè)計公司花費了相當多的時間在較低齒輪但高扭矩的設(shè)計上。在大多數(shù)情況下，地形可能使這樣的輪胎打滑。例如，在相當堅硬的沙質(zhì)路面，它可能允許輪胎咬進去，從而使扭轉(zhuǎn)疲勞顯著大于在平穩(wěn)的道路行駛。雖然在大程度上這取決于速度，但縱向和橫向打滑時將更嚴重。沖擊負荷也會影響剎車和加速扭矩，這種影響是取決于速度的。
準雙曲面齒輪傳動是錐齒輪傳動中的普遍形式，螺旋錐齒輪是它的一種特殊情況。他們的優(yōu)點是齒輪的具體比例較大，其嚙合區(qū)較大，而且低噪音,他們本質(zhì)上是更強大，更持久和更耐用。
主減速器的作用是用來降低傳動軸傳來的轉(zhuǎn)速而增大旋轉(zhuǎn)扭矩，并將扭矩改變傳動方向，經(jīng)差速器傳給半軸。主減速器的結(jié)構(gòu)形式主要是根據(jù)齒輪類型、減速器形式不同而不同。主減速器的齒輪主要有螺旋錐齒輪、雙曲面齒輪、圓柱齒輪和蝸輪蝸桿等形式。
雙級主減速器與單級相比，在保證離地間隙相同時可得到大的傳動比，i0一般為7～12。但是尺寸、質(zhì)量均較大，成本較高。它主要應(yīng)用于中、重型貨車、越野車和大客車上。
整體式雙級主減速器有多種結(jié)構(gòu)方案：第一級為錐齒輪，第二級為圓柱齒輪；第一級為錐齒輪，第二級為行星齒輪；第一級為行星齒輪，第二級為錐齒輪；第一級為圓柱齒輪，第二級為錐齒輪。
對于第一級為錐齒輪、第二級為圓柱齒輪的雙級主減速器，可有縱向水平、斜向和垂向三種布置方案。
縱向水平布置可以使總成的垂向輪廓尺寸減小，從而降低汽車的質(zhì)心高度，但使縱向尺寸增加，用在長軸距汽車上可適當減小傳動軸長度，但不利于短軸距汽車的總布置，會使傳動軸過短，導(dǎo)致萬向傳動軸夾角加大。垂向布置使驅(qū)動橋縱向尺寸減小，可減小萬向傳動軸夾角，但由于主減速器殼固定在橋殼的上方，不僅使垂向輪廓尺寸增大，而且降低了橋殼剛度，不利于齒輪工作。這種布置可便于貫通式驅(qū)動橋的布置。斜向布置對傳動軸布置和提高橋殼剛度有利。
在具有錐齒輪和圓柱齒輪的雙級主減速器中分配傳動比時，圓柱齒輪副和錐齒輪副傳動比的比值一般為1.4～2.0，而且錐齒輪副傳動比一般為1.7～3.3，這樣可減小錐齒輪嚙合時的軸向載荷和作用在從動錐齒輪及圓柱齒輪上的載荷，同時可使主動錐齒輪的齒數(shù)適當增多，使其支承軸頸的尺寸適當加大，以改善其支承剛度，提高嚙合平穩(wěn)性和工作可靠性。
現(xiàn)代車橋中，齒輪潤滑油的選擇是至關(guān)重要的。汽車運行在高速公路上，車橋油溫可以最終上升，甚至高于130℃ ，所以車橋外殼通風是很重要的。通過兩個軸承攜帶的小齒輪來達到改善的目的。因此，形狀和尺寸之間的間隙，套管等可能都是至關(guān)重要的，足夠的排水必須提供的潤滑油的流向，通過渠道流入小齒輪軸承座，再回到套管。
在齒輪軸承中，圓錐滾子軸承普遍應(yīng)用在齒輪。他們有大量的承載能力，通過穩(wěn)定的、準確定位。法蘭密封的齒輪對于抗高溫和相對較高的速度是至關(guān)重要的。
錐齒輪齒面過寬并不能增大齒輪的強度和壽命，反而會導(dǎo)致因錐齒輪輪齒小端齒溝變窄引起的切削刀頭頂面寬過窄及刀尖圓角過小。這樣，不但減小了齒根圓半徑，加大了應(yīng)力集中，還降低了刀具的使用壽命。此外，在安裝時有位置偏差或由于制造、熱處理變形等原因，使齒輪工作時載荷集中于輪齒小端，會引起輪齒小端過早損壞和疲勞損傷。另外，齒面過寬也會引起裝配空間的減小。但是齒面過窄，輪齒表面的耐磨性會降低。
為改善新齒輪的磨合，防止其在運行初期出現(xiàn)早期的磨損、擦傷、膠合或咬死，錐齒輪在熱處理及精加工后，作厚度為0.005～0.020mm的磷化處理或鍍銅、鍍錫處理。對齒面進行應(yīng)力噴丸處理，可提高25％的齒輪壽命。對于滑動速度高的齒輪，可進行滲硫處理以提高耐磨性。滲硫后摩擦因數(shù)可顯著降低，即使?jié)櫥瑮l件較差，也能防止齒面擦傷、咬死和膠合。
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