机械毕业设计英文外文翻译547运动型7速双离合器变速器系统.docx

1、机械毕业设计英文外文翻译547运动型7速双离合器变速器系统附录附录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 i

2、t 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 pri

3、nciple, 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 deta

4、il. 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 count

5、ershaft 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 speed

6、s 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

7、 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 tra

8、nsmission 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 remo

9、val, 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 d

10、ifferent 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 le

11、vel 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 detec

12、ting 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 transmissio

13、n 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 manu

14、al 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

15、 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 th

16、e 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

17、. 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

18、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

19、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

20、 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 vehi

21、cles 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 multiplicat

22、ion 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 simi

23、larity 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

24、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 are

25、a 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 distinguish

26、es 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

27、 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 instal

28、lation 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 ac

29、hieve 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 s

30、trength 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 hi

31、gh 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 con

32、trol 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