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运动型7速双离合器变速器系统外文文献翻译@中英文翻译@外文翻译.doc
双离合器式自动变速器的七挡齿轮变速器设计【优秀含16张CAD图纸+汽车车辆工程毕业设计】
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双离合器式自动变速器的七挡齿轮变速器设计【优秀含16张CAD图纸+汽车车辆工程毕业设计】,优秀含16张CAD图纸+汽车车辆工程毕业设计,离合器,自动变速器,齿轮,变速器,设计,优秀,16,CAD,图纸,汽车,车辆,工程,毕业设计
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黑龙江工程学院本科生毕业设计附录附录A 外文文献原文7-Speed Dual Clutch Transmission System for Sporty ApplicationABSTRACT:With its 7-speed dual clutch transmission, ZF has introduced an innovative transmission for sporty applications. The close ratios combined with extremely spontaneous drive behavior makes it an ideal transmission for sporty applications. This article describes the compact gear set with lubrication by injection for improving the level of efficiency and increasing the engine-speed-strength, the dual clutch unit as well as the hydraulic control unit, which is based on the pre-control principle, are also described in detail. The hy-draulic control principle provides the option of a hydraulic cruise mode in the event of an electronics failure. In addition to the transmission design, functional features that also highlight the sporty character of the transmission are described in detail. Key words: Automatic transmission; Dual clutch; Vehicle connection; Efficiency1 IntroductionWhen it comes to the field of automatic transmissions, dual clutch systems currently represent the benchmark in terms of spontaneity and sportiness. In this type of transmission, which is based on a countershaft transmission, these advantages are combined with a very direct vehicle connection, high rpm performance, and excellent transmission efficiency.The 7-speed dual clutch transmission for the standard driveline presented here is designed for a torque capacity of up to 520 Nm and rotational speeds of up to 9250 rpms. In order to be able to achieve these performance data in the existing installation space, a concept was developed in which an oil chamber as well as lubrication by injection are used. Before introducing the transmissions several unique features in more detail below, an overview of the basic transmission design will be presented, Fig. 1.The engine torque is introduced to the dual clutch via a torsion damper (not shown in Fig. 1). The multidisk clutches in the dual clutch are radially nested in one another and transfer the torque to both input shafts in the countershaft transmission gear set. In this case, due to the installation space, the countershaft is not located under the main shaft, but is tilted laterally. This becomes possible because the concept is based on lubrication by injection with a dry sump. On the one hand, lubrication by injection improves heat removal, on the other, there are no noticeable losses due to the gears splashing in the oil pan. The oil is supplied to the transmission via an internal gear pump which is driven by a spur gear train behind the dual clutch. With the help of a spur gear train, the drive unit has the advantage that, via different gear ratio phases and depending on the intended use, the flow rate and the max. speed of the pump can be adapted. An additional advantage is that based on theresulting I proved installation space, an optimal ratio between the pump width and the pump diameter can be achieved for the pumps level of efficiency. The hydraulic control unit is arranged under the gear set. The hydraulic unit supplies the clutch, based on need, with pressure and cooling oil as well as shift actuators. The latter are arranged laterally to the gear set and work with double-acting cylinders. The sensor for detecting the position of the gearshifts is attached directly onto the four gearshifts. The transmission has an external control unit.Fig.1Overview dual clutch transmission (DCT)2 Seven speeds with sophisticated stepping-a concept for extrme sporti- nessThe gear set concept of the dual clutch transmission introduced here was developed in house taking into consideration the following requirements:High power densityHigh speed endurance strength up to 9250 rpm Variability and modular designRepresentation of transmission-ratio spreads of about 4.7 and 6.8 with 7 speedsUse of existing synergies for manual transmissionsAfter extensive systematic development of the gear set in which many thousands of variants were produced and compared, the gear set concept that is illustrated in Fig. 2 is the final variant and the ideal concept for achieving the goals specified.The gear set selected is based on the constant drive concept and consists of two concentric drive shafts each of which are driven by one of the two multidisk clutches in theFig.2Gear set scheme of 7D variantdual clutch, two countershafts also concentric to one another, a main shaft and an output shaft. The gear ratios are engaged by the four synchronizer units A/B, C/D, E/F, and G/H, which are arranged on the main shaft and on the hollow countershaft and these are connected to the loose wheels or the adjacent shafts. An important feature in the gear set is the connectability of both countershafts through the C/D synchronizer unit. In the D shift position, the gear ratios selected in this way can be doubly used which reduces construction costs compared to conventional dual clutch gear sets. Similarly, this feature is used in first gear because then the vehicle is started up using the more powerful K1 clutch. Because of this dual use of the last gear level in the transmission for the first and second gear, the desired ratio step 1-2 is achieved through the transmission ratios of both constant drive phases.The use of the K1 clutch for starting up in first gear results inevitably in the direct gear also being assigned to the odd subsection. In this case, the fifth and seventh gears can be selected as a direct drive. With this feature, it was possible to develop a modular gear set which, on just a few changes,contains two different transmission gear ratio variants with fundamentally different characters.For the first version, with an overall spread of about 4 . 7 , the seventh gear is selected as a direct gear (called the 7D variant). Fig. 2 shows the relevant gear set diagram with the performance flows in all speeds. Due to its sophisticated gear steps, this transmission is highly suitable for very sporty vehicles that need only a little transmission stepping due to the high rotating engine. Optimal tractive power can be provided at any time during vehicle operation.The second version is based on the 7D variant, however, fifth gear was selected as the direct drive. When maintaining the torque multiplication ratio and in adapting the transmission ratio of several lower gear levels, you get the 5D variant with a considerably higher transmission-ratio spread for vehicles with increased comfort demands and simultaneously reduced consumption.Fig. 3 illustrates the design of the 7D variant. The main similarity with existing manual transmissions for standard transmissions is noticeable. Due to the compact gear set design, the sufficient shaft dimensioning and the favorable arrangement in proximity of the bearing of the high transmitting ratios, central bearing glasses were not necessary despite the proportionally large bearing clearance.Overall, only two housing bearing levels are necessary where the front level is located behind both constant gears. In addition, a very compact and inexpensive transmission design could be implemented based on the bearing concept selected, especially in the area of the hollow shaft.Fig.3Sectional Drawing of 7D variant3 The dual clutchThe central module of this highly topical transmission concept is the wet dual clutch. With a broad spectrum of technical features, it implements the functional provisions of the transmission control unit and thus distinguishes the special character of this transmission concept.Very fast delay times, low inertia and good, comfortable friction value progressions facilitate, very sporty handling with highly dynamic gear shifting and comfortable cruising at a high level of efficiency. The dual clutch placed directly on the transmission input accepts the engine torque from thtorsion damper and feeds it to one of the two subsections, depending on the situation.Safety considerations have led to a normall open design.The radial arrangement of the multidisk pack age represents the best combination of performanc and installation space need, Fig. 4.Fig.4Dual clutchCareful lining and oil selection as well as intensive enhancement of this tribological system are the requirements for comfort and performance of this clutch throughout its service life.Through intense testing and detailed calculations, it was possible to achieve a very high therma loading capacity. As part of the process, the lining type, dimensioning, and grooving as well as equal distribution of thermal load and oil flow in the multidisk package are decisive design features.Low torque drag even with low temperatures as well as high speed endurance strength support comfort and a high level of sportiness, but are also important safety requirements.Rotating, centrifugal force-compensating clutch cylinders with hysteresis optimized gaskets make the clutches easy to control. Integrated plate springs reliably accept rapid piston resetting even at high speeds.In the case of an open clutch, only transmission input shafts with very low additional mass inertia are used. This supports rapid synchronizing sequences and a long service life of the synchronizer units.4 The hydraulic control unitIn the present dual clutch transmission, the hydraulic control unit fulfills the following tasks:Actuating the dual clutchShifting the gearshifts, i. e. engaging/synchronizing the gearCooling the dual clutchGear lubricationEmergency stop function in case of complete failure of transmission electronicsSeveral features in the hydraulic control unit as well as criteria for the selection of the control concept are going to be described in more detail below.4.1 PerformanceThe use of the dual clutch transmission in sporty vehicles demands high performance from the hydraulic control unit, especially with regard to the first two tasks because the timely handling of these tasks come into play in gear shifting and gear shifting times.That is why particular value is placed on the selection of the right control unit concept as part of the system design. During the decision process, the choice was made, in principle, between two concepts, Fig. 5.Fig.5Control concept direct control / precontrolPrecontrol of the valvesDirect control of the valves (so-called cartridge valves)In case of direct control, the valve that is used for pressure control, e.g. a clutch, is directly connected to the power-generating proportional solenoids and provides the main pressure to the corresponding clutch pressure.The precontrol uses the pressure that is supplied by a pressure controller, for example, to actuate an additional valve that supplies the clutch pressure from the main pressure.To assess the performance of both concepts, a larger number of compared measurements were performed with different systems, of which two systems shall be considered here:ZF hydraulic control unit with precontrol for DCT standard driveComparative hydraulic control unit with direct controlA reference clutch was used as the clutch to engage. Criteria for assessing the performance were (see also Fig. 6):Fig.6Delay, increase/rise, and fall times. Red curve: Power /Electric current. Green curve: Clutch pressureDelay time, 1 to 4Time of step response until clutch inflation pressure, 1 to 2Time of the step response up to 90% of the main pressure 1 to 3Time of pressure drop (emptying times), 5 to 6Fig. 6 shows, as an example, the times for a transmission oil temperature of + 20C to be reached. One notices that the direct control first in dicates a lower delay time (14.3 ms) compared to the precontrol (30.1 ms), see also time of brand 1 to 4.For increase to clutch inflation pressure or to 90% of the main pressureshows, however, the advantage of the precontrolled system (see also summarizing tab 1).Emptying times, also present a disadvantage for direct control. Trans-mission oil temperature of -20C also show comparable results for step responses and fall times.All of the tests support the statement that direct control has an advantageous effect with small oil volumes. However, if large oil volumes have to be transported, precontrol valves are to be preferred due to larger opening cross-sections.4.2 Operational safetyOperational safety is determined essentially due to the soiling tendency because the so-called silting can lead to the valves getting jammed. Provocation tests with transmission-specific environmental conditions (dirty oil) demonstrated the influences of soiling on the characteristic curves. Technical, trouble-free characteristic curve progressions could be illustrated only with a high dither amplitude in valve actuation, which leads, in turn, to increased valve wear-and-tear due to the micro movements that it causes. The increased tendency toward soiling can result needing a fine filter.4.3 CostsIn addition to the delay time comparison as well as assessing the operational safety, the costs were relevant for a final evaluation. The compari son with regard to the hydraulic and electro-mag netic components shows that a precontrol system has cost benefits compared to a direct control system. Added to this are the higher flows with the actuation of direct control valves, which, in turn, result in a more expensive TCU. Furthermore, in opting for precontrol, ZF is able to pool together pressure controllers in large quantities because these, too, are used in the automatic ZF planetary gear set.4.4 Emergency stop functionIn case there is a complete outage in the transmission electronics, a hydraulic emergency stop function is actuated in the transmission. The clutch that is pressurized with a larger amount of pressure in the event of a system outage will continue to be pressurized. This condition is maintained until an adjustable engine speed threshold is achieved, then the clutch opens in order to prevent the engine from being choked. It is not possible to re-start this system.5 Sporty functionsFor function developers, the dual clutch transmission offers the opportunity to combine the comfort of a stepped automatic transmission with the dynamics and sportiness of a countershaft transmission. Connected, therefore, are typical catalog values, such as time from zero to 100 kilometers per hour or the time from 80 to 120 kilometers per hour with correspondingly fast kick-down shifting, but also subjective acceleration sensitivity during a shifting sequence where the purist among the manual transmission drivers still wants to feel that jolt of acceleration.One function especially designed for the dual clutch transmission in sports cars is the race startfunction. The race start is a function used to achieve optimal acceleration from a standstill, i.e. in the shortest time from 0 to 100 km/h. The sequence progresses as follows:The engine is brought to a suitably high rpm with the clutch engaged in first gear. The driver simultaneously actuates the brakes with the lef foot so that the clutch can already be lightly engaged and the gas pedal (full throttle) in order to bring the vehicle up to the target speed. By simultaneously pressing and holding an operating element, such as the selector lever or a push button on the steering wheel, the race start intention is conveyed to the system, the engine speed adjusted and the start up prevented until the driver releases the brake. During the race start, the clutch is closed under the control of the wheel slip with which the optimal acceleration is achieved and by exploiting the dynamic engine torque (inertia torque). The entire procedure progresses automatically once the driver releases so that even an inexperienced drivercan achieve the best possible drive performance figures. Obviously, the driver can cancel the procedure by removing his/her foot from the gas pedal or touching the brakes. Also, the system recognizes when the street conditions do not permit a race start, such as wet roads, for example. Due to the optimal start-up and a shifting sequence into second gear free of traction interruption (see also sports shifting), the race start function enables the acceleration time of 0 to 100 km/h to be improved by an average of 0.2 sec compared to a car with a manual transmission. At the same time, this functionality helps avoid improper use and resulting clutch overload.The top chart in Fig. 7 illustrates the engine and transmission input shaft speed, the lower chart shows the vehicles longitudinal acceleration. Starting with a cranking speed of 6,800 rpm, the clutch begins to close, which leads to an engine pressure up to about 4,000 rpm. The dynamic engine torque used to achieve this results in an acceleration of 0.7-0.9 g. In the process, noticeable vibrations in the transmission input shaft speed signal develop due to the wheel slip regulation. After about 1.2 sec, the vehicle is accelerated only by the engine torque with approx. 0.5 g. It must be mentioned here that this test was performed using a vehicle with very high traction. In most cases, a starting speed of only up to about 4,000 rpm is reasonable.A further function developed for the dual clutch transmission is so-called sports shifting. This is described in more detail below.In general, a gear-shift change by the driver is only perceived acoustically by the change in the engine speed. The transition from the acceleration level of the original gear toFig.7Measurement of a race starthe new gear should be made smoothly and continuously. This also corresponds to the standard shifting sequences in auto-matic and dual clutch transmissions. However, many drivers of sporty cars wish that they had the option of both distinctive comfort shifting sequences as well as sporty shifting sequences, which, besides the haptic response (acceleration jolt), also have an acceleration advantage as a result. To this end, the dynamic engine torque can also be used again. The requirement for this is the torque capacity of the dual clutch which has to be able to transmit this torque increase. As the possible torque increase depends on the gradients of the engine speed, this can be used particularly effectively in shifting gears with a large speed difference with the target gear (large ratio spread/ratio step), which is why the gear changes 1-2, 2-3, and 3-4 are offered. In the process, sports shifting from the frst to second gear can serve as a supplement to the ace start for improving the acceleration time from to 100 km/h. As the use of the dynamic torque is pure application topic, we distinguish, as a rule,between three shifting systems. Fig. 8 illustrates he stylized differences and features between the hifting systems, Fig. 9 shows an original measurement from a prototype vehicle.The top chart shows the respective engine and ransmission speed, the bottom chart shows the orques from both clutches. The bottom line in the hart represents the clutch from the target gear that is used to achieve the torque increase during engine sp eed adjustment and thereby acceleration gains.Fig.8Simplified depiction of acceleration procedures withFig.9Measurement of sports shift 2-3 in the vehicle附录B 外文文献翻译运动型7速双离合器变速器系统摘要：ZF公司的7速双离合器变速器是一款创新型的、适用于运动型车辆的变速器。精密的速比和自然拥有的极佳驾驶性能使得它成为运动型车辆理想的变速装置。本文对该变速器紧凑的齿轮机构、可改善效率和提高发动机-速度-强度的直接喷射润滑系统,双离合器系统及基于预先控制原理的液压控制单元等作了详细介绍。在出现电气故障时液压控制系统可选用液压巡航模式。另外,变速器设计、功能特性等也都体现出变速器具有鲜明的运动特征。关键词：自动变速器;双离合器;车辆连接;效率1.前言提及自动变速器时,双离合器系统被普遍认为是运动型的标杆。基于中间轴结构的该类变速器的优点是非常直接的“车辆连接”、高转速性能和及其优越的变速器效率。本文介绍的用于标准型传动系统的7速双离合器变速器的最大转矩可达520 Nm、最高转速为9250 rpm。为在现有安装空间内实现这些性能数据,创造性的引入了储油室和润滑油直接喷射概念。在详细介绍变速器各特点之前,首先对变速器给出一个总的描述,见图1。图1双离合器变速器(DCT)剖视图发动机转矩经过扭转减振器(未在图1中表示)传递给双离合器。双离合器中的多片式离合器沿径向互相嵌套并将转矩通过两输入轴传递给中间轴齿轮装置。这里,因为安装空间的缘故,中间轴并不位于主轴下方,而是横向斜置。用于采用了带干油箱的直接喷射润滑,才有这样的可能。一方面,直接喷射改善了热传递,另一方面不会在油底壳中出现明显的飞溅损失。向变速器供给的润滑油由内啮合齿轮泵提供,利用齿轮机构驱动的该泵安装在双离合器后面。借助于该齿轮机构,驱动装置的优点是可根据不同的齿轮速比和预期的需要获得适合的流速和油泵最高转速。另一优点是改善了安装空间,可根据油泵效率实现油泵宽度和直径之间的最佳比例。液压控制单元安装在齿轮机构的下方。液压控制单元根据需要向离合器和换档执行机构提供压力和冷却润滑油。而采用双向作用油缸的换档执行机构则安装在齿轮机构的侧面。检测档位位置的传感器直接安装在四根换档轴上。变速器具有一个外部控制单元。2.七个精密档位-极具运动性的概念这里引入的双离合器变速器齿轮机构考虑了以下需求：高动力密度；高达9250 rpm的高速耐久强度；可变性和模块化设计；变速特性-速比范围从4.7到6.8；源于现有的手动变速器。据此对齿轮机构进行了广泛的系统开发,引入并比较了数以千计的变量,图2所示的齿轮机构是最终形式,是一个满足各项目标的理想概念。所选择的齿轮机构是基于常规传动概念,变速器由各由双离合器中的一组多片式离合器驱动的两根同心传动轴、两根同心的副轴、主轴和输出轴组成。齿轮速比的变化由4组同步器A/B、C/D、E/F和G/H实现,这些同步器布置在主轴和中空的中间轴上并连接到自由轮或相邻轴上。齿轮机构的一个主要特征是两中间轴通过C/D同步器连接。在D位置可两次选择齿轮速比,与常规双离合器变速器相比降低了成本。同样,该特征也被应用在1档齿轮上,因此当车辆起步时可利用更强有力的K1离合器。由于变速器1档和2档均使用了最后一对齿轮,1-2档之间的速比是由两常啮合齿轮副确定。利用K1离合器和1档起步不可避免的会导致直接档齿轮设定成奇数。这时,5档和7档齿轮可选作直接档传动。据此可开发一模块化齿轮机构,仅需少量改变而获得两种具有不同特性的齿轮速比。第一种结构的总速比是4.7,7档齿轮作为直接档(称为7D型)。图2给出了齿轮机构的动力流。借助于精密的速比间隔,该变速器非常适用于高发动机转速和“小”速比间隔的运动型车辆。可在车辆的各种工况下获得最佳的牵引力。第二种结构基于7D型,但将5档作为直接档。当维持转矩放大倍数和稍稍减少变速器档位数时, 5D型仍具有相当高的变速器总速比范围并且提高了舒适性同时也降图27D型齿轮机构简图低了油耗。图3是7D变速器的设计图。和现有标准的手动变速器的相似之处是显见的。由于齿轮机构设计紧凑,各轴具有足够的尺寸并且有利于在大速比处布置轴承,中央轴承罩无需顾及大的轴承间隙。由于前轴承座位于两常啮合齿轮后部,因此仅需两个轴承座即可。另外,非常紧凑和廉价的变速器设计也是基于对轴承的选择,特别在空心轴方面。图37D型变速器剖面图3.双离合器该变速器的核心模块是湿式双离合器。该离合器具有一个宽型谱的技术特征,能实现变速器控制单元的功能和辨别该变速器的专有特征。离合器延迟时间短、惯量小、动作过程中具有良好和舒适的摩擦系数、极具运动性的高动态换档特性、行驶舒适以及高效率。双离合器直接安装在变速器的输入端,发动机转矩经扭转减振器后根据具体情况传递给两离合器中的任一个。出于安全考虑,离合器设计成“常开”状态。沿径向布置的多片离合器具有最佳的性能和安装空间,见图4。图4双离合器确保离合器在使用寿命中其性能和舒适性取决于摩擦片衬里、润滑油的选择和提高该摩擦学系统的性能。经过大量试验和详细计算,获得了相当高的热负载特性。作为其中的一部分,摩擦片衬里的类型、尺寸、沟槽以及在离合器壳体中热负荷耗散和润滑油流动等都是决定性的设计特点。离合器甚至在低温情况下也具有低的牵引转矩,并具有高速疲劳强度、运动舒适性和高水平的运动性,同时也能满足安全性方面需要。装有滞后优化垫圈和配备有离心力补偿的离合器主缸使得离合器操控更容易。板簧能确保高速时活塞的快速回位。在离合器断开情况下,变速器输入轴仅有非常低的附加转动惯量。这样可确保快速同步和同步器的长寿命。4.液压控制单元在现有的双离合器变速器中,液压控制单元应完成下列任务:操纵双离合器；换档,即齿轮的结合/同步；冷却双离合器；变速器电子系统完全失效时的应急停车功能；液压控制单元的几个特征和控制概念的选择标准详见以下各小节。（1）性能在运
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