DUAL CLUTCH TRANSMISSION FOR A MOTOR VEHICLE, IN PARTICULAR FOR AN AUTOMOBILE, METHOD FOR OPERATING A DUAL CLUTCH TRANSMISSION OF THIS TYPE AND MOTOR VEHICLE

Abstract

A dual clutch transmission for a motor vehicle, with a first sub-transmission, with a second sub-transmission, with a first clutch associated with the first sub-transmission, and with a second clutch associated with the second sub-transmission. The dual clutch transmission is designed to be shifted into a parking lock state, in which two gears of one of the sub-transmissions are simultaneously engaged, and in the lock state, the two gears of the one first sub-transmission are simultaneously engaged. A first gear wheel of a first of the gears, which is designed as loose wheel and rotatably arranged on a first shaft of the dual clutch transmission, is connected in a torque-proof manner to the first shaft, by a first switching element.

Claims

1-10. (canceled)

11. A dual clutch transmission for a motor vehicle, comprising: a first sub-transmission, with a second sub-transmission, with a first clutch associated with the first sub-transmission, and with a second clutch associated with the second sub-transmission, wherein the dual clutch transmission is designed to be shifted into a parking lock state, in which two gears of one of the sub-transmissions are simultaneously engaged, wherein in the lock state, the two gears of the one first sub-transmission are simultaneously engaged, wherein a first gear wheel of a first of the gears, which first gear wheel is designed as a loose wheel and rotatably arranged on a first shaft of the dual clutch transmission, is connected in a torque-proof manner to the first shaft, by a first switching element, associated with the first gear, arranged on the first shaft, and connected in a torque-proof manner to the first shaft, while a second gear wheel of the second gear, which second gear wheel is designed as loose wheel and rotatably arranged on a second shaft of the dual clutch transmission, is connected in a torque-proof manner to the second shaft by a second switching element, associated with the second gear, arranged on the second shaft, and connected in a torque-proof manner to the second shaft.

12. The dual clutch transmission according to claim 11, wherein the one sub-transmission comprises a reverse gear.

13. The dual clutch transmission according to claim 12, wherein one of the gears is the reverse gear.

14. The dual clutch transmission according to claim 11, wherein one of the gears is a forward gear.

15. The dual clutch transmission according to claim 11, wherein the respective switching element is a positive locking switching element, in particular a claw clutch.

16. The dual clutch transmission according to claim 11, wherein in the parking lock state, both clutches are simultaneously closed.

17. A method for operating a dual clutch transmission of a motor vehicle, comprising a first sub-transmission, with second sub-transmission, a first clutch associated with the first sub-transmission, and a second clutch associated with the second sub-transmission, wherein the dual clutch transmission is in a parking lock state, in which two gears of one of the sub-transmissions are simultaneously engaged, wherein in the parking lock state, the two gears of the one sub-transmission are simultaneously engaged, wherein a first gear wheel of a first of the gears, which first gear wheel is designed as a loose wheel and rotatably arranged on a first shaft of the dual clutch transmission, is connected in a torque-proof manner to the first shaft by a first switching element, associated with the first gear, arranged on the first shaft, and connected in a torque-proof manner to the first shaft, while a second gear wheel of the second gear, which second gear wheel is designed as a loose wheel and rotatably arranged on a second shaft of the dual clutch transmission, is connected in a torque-proof manner to the second shaft by a second switching element, associated with the second gear, arranged on the second shaft, and connected in a torque-proof manner to the second shaft.

18. The method according to claim 17, wherein to end the parking lock state, the following steps are carried out: a) introducing a torque, caused by a drive element of the motor vehicle, via one of the clutches into the one sub-transmission, while the gears of the one sub-transmission are engaged; and b) disengaging at least one of the gears of the one sub-transmission, which are simultaneously engaged in step a).

19. The method according to claim 18, wherein in step b), the at least one gear is disengaged, while the other gear, engaged in step a), remains engaged.

20. A motor vehicle, with a dual clutch transmission comprising: a first sub-transmission, with a second sub-transmission, with a first clutch associated with the first sub-transmission, and with a second clutch associated with the second sub-transmission, wherein the dual clutch transmission is designed to be shifted into a parking lock state, in which two gears of one of the sub-transmissions are simultaneously engaged, wherein in the lock state, the two gears of the one first sub-transmission are simultaneously engaged, wherein a first gear wheel of a first of the gears, which first gear wheel is designed as a loose wheel and rotatably arranged on a first shaft of the dual clutch transmission, is connected in a torque-proof manner to the first shaft, by a first switching element, associated with the first gear, arranged on the first shaft, and connected in a torque-proof manner to the first shaft, while a second gear wheel of the second gear, which second gear wheel is designed as loose wheel and rotatably arranged on a second shaft of the dual clutch transmission, is connected in a torque-proof manner to the second shaft by a second switching element, associated with the second gear, arranged on the second shaft, and connected in a torque-proof manner to the second shaft.

21. The dual clutch transmission according to claim 12, wherein one of the gears is a forward gear.

22. The dual clutch transmission according to claim 13, wherein one of the gears is a forward gear.

23. The dual clutch transmission according to claim 12, wherein the respective switching element is a positive locking switching element, in particular a claw clutch.

24. The dual clutch transmission according to claim 13, wherein the respective switching element is a positive locking switching element, in particular a claw clutch.

25. The dual clutch transmission according to claim 14, wherein the respective switching element is a positive locking switching element, in particular a claw clutch.

26. The dual clutch transmission according to claim 12, wherein in the parking lock state, both clutches are simultaneously closed.

27. The dual clutch transmission according to claim 13, wherein in the parking lock state, both clutches are simultaneously closed.

28. The dual clutch transmission according to claim 14, wherein in the parking lock state, both clutches are simultaneously closed.

29. The dual clutch transmission according to claim 15, wherein in the parking lock state, both clutches are simultaneously closed.

Description

BRIEF DESCRIPTION OF THE FIG.

[0025] Below, an embodiment example of the invention is described. For this purpose, the single FIG. shows a diagrammatic representation of a dual clutch transmission of a motor vehicle according to the invention.

[0026] The embodiment examples explained below are preferred embodiments of the invention. In the embodiment examples, the described components of the embodiments each represent individual features of the invention, which are to be considered independently of one another and which also each develop the invention independently of one another. Therefore, the disclosure should also include other combinations than the represented combinations of the features of the embodiment. Moreover, the described embodiment can also be supplemented by other already described features of the invention.

DETAILED DESCRIPTION

[0027] The single FIG. shows in a diagrammatic representation a dual clutch transmission 10 of a motor vehicle which is preferably designed as car or preferably as passenger car. The motor vehicle comprises at least one drive motor, by means of which at least two wheels of the motor vehicle can be driven via the dual clutch transmission 10. By driving the wheels, the motor vehicle as a whole can be or is driven. The wheels are ground contact elements, via which the motor vehicle can be or is supported on a ground in vehicle vertical direction downward. The wheels are also referred to as vehicle wheels and they roll on the ground when the motor vehicle is driven along the ground, while it is supported on a ground in vehicle vertical direction downward. The drive motor is represented particularly diagrammatically in the FIG. and designated 12 therein. The drive motor 12 can be an internal combustion engine which is designed, for example, as a reciprocating internal combustion engine, or else an electric machine. The drive motor 12 comprises an output shaft 14 designed, for example, as crankshaft.

[0028] The dual clutch transmission 10 comprises a first sub-transmission 16 which includes, for example, three first gears 18a-c. In addition, the first sub-transmission 16 comprises a first transmission input shaft 20 which in the present case is designed as a hollow shaft. The dual clutch transmission 10, in addition, includes a second sub-transmission 22 which comprises a second transmission input shaft 24 and second gears 26a-c. The gears 18a-c are, for example, odd-numbered gears or they also referred to as odd-numbered gears, wherein, for example, the gear 18a can be the so-called first gear, the gear 18b can be the so-called third gear, and the gear 18c can be the so-called fifth gear of the dual clutch transmission 10. However, in the embodiment example illustrated in the FIG., the gear 18a is a reverse gear for causing a reverse travel of the motor vehicle. In contrast, the gears 18b and 18c are forward gears for causing a respective forward travel of the motor vehicle.

[0029] The gears 26a-c, for example, are also referred to as even-numbered gears or they are so-called even-numbered gears of the dual clutch transmission 10, wherein, for example, the gear 26a can be the second gear, the gear 26b can be the fourth gear, and the gear 26c can be the sixth gear of the dual clutch transmission 10. The gears 26a-c are forward gears for causing a forward travel of the motor vehicle.

[0030] The dual clutch transmission 10 comprises a first clutch 28 which is associated with the sub-transmission 16 and which, for example with respect to the sub-transmissions 16 and 22, in particular with respect to the transmission input shafts 20 and 24, is associated exclusively with the sub-transmission 16 or exclusively with the transmission input shaft 20 but not with the sub-transmission 22 and not with the transmission input shaft 24. The dual clutch transmission 10, in addition, includes a second clutch 30 which is associated with the sub-transmission 22 and which, for example with respect to the sub-transmissions 16 and 22, in particular with respect to the transmission input shafts 20 and 24, is associated exclusively with the sub-transmission 22 or exclusively with the transmission input shaft 24 but not with the sub-transmission 16 or, however, not with the transmission input shaft 20. This means that, by means of the clutch 28, with respect to the transmission input shafts 20 and 24, exclusively the transmission input shaft 20 can be connected in a torque-transferring manner to the output shaft 14. By means of the clutch 30, with respect to the transmission input shafts 20 and 24, exclusively the transmission input shaft 24 can be connected or coupled in a torque-transferring manner to the output shaft 14. In addition, the transmission input shaft 20 is designed as a hollow shaft which in the present case is passed through at least partially, in particular at least mostly, or completely, by the transmission input shaft 24 designed as solid shaft.

[0031] The respective sub-transmission 16 to 22 also comprises a side shaft 32 or 34 also referred to as auxiliary shaft. The dual clutch transmission 10, in addition, comprises a transmission output shaft 36 which is common to the sub-transmissions 16 and 20, in particular the side shafts 32 and 34 and which can be driven by the side shafts 32 and 34 and is also referred to as transmission output shaft.

[0032] Via its output shaft 14, the drive motor 12 can provide at least one drive torque which can be introduced via the respective clutch 28 or 30 into the respective sub-transmission 16 or 22 and over it to the transmission output shaft 36. In this way, via the dual clutch transmission 10, the aforementioned wheels can be driven by the drive motor 12. Preferably, it is provided that the clutch 30, when the clutch 28 is closed, in addition, it is preferably provided that the clutch 28, when the clutch 30 is closed, is open. Thus, preferably at all times only one of the sub-transmissions 16 and 22 is connected via the respective clutch 28 or 30 in a torque-transferring manner to the output shaft 14.

[0033] The dual clutch transmission 10 is designed to be switched into a parking lock state, in particular after an acquisition of an actuation of an operating element of the motor vehicle caused by a person. In other words, during a method of operating the dual clutch transmission 10, it can be provided that the dual clutch transmission 10 is switched during the method into a parking lock state. In the parking lock state, for example, the gears 18a and 18c of the sub-transmission 16 are simultaneously engaged, in particular while the gears or all the gears 26a-c of the respective other sub-transmission 22 are disengaged. In addition, it is preferably provided that, in the parking lock state, one of the clutches 28 and 30 is closed, while the respective other clutch 30 or 28 is open, or, in the parking lock state, both clutches 28 and 30 are simultaneously open, or, in the parking lock state, both clutches 28 and 30 are simultaneously closed. In the parking lock state, a mechanical parking lock is activated, since the sub-transmission 16, also referred to as closed sub-transmission, can be or is tensioned. Thereby, in particular if the motor vehicle is parked on a hill or on a slope, an undesired rolling away is prevented, since, due to the tensioning of the sub-transmission 16, the wheels are secured against rotation. In particular, if the motor vehicle is parked on the slope or on a slope, a downhill force resulting from the weight of the motor vehicle acts on the motor vehicle. A downhill torque results from this downhill force, and, for example, in the parking lock state, said downhill torque is introduced via the wheels and the transmission output shaft 36 into the dual clutch transmission 10, in particular into the sub-transmission 16 and thus acts on the dual clutch transmission 10, in particular on the sub-transmission 16. Thus, the downhill torque acts as a tensioning torque by which the sub-transmission 16 is tensioned. Thereby, the aforementioned mechanical parking lock is implemented and activated.

[0034] Using the gears 18a and 18c, it can be detected that, for example, the gear 18a comprises two gear wheels 38 and 40, wherein the gear wheel 40 is arranged on the transmission input shaft 20 and the gear wheel 38 is arranged on the side shaft 32. The gear 18c includes two mutually meshing gear wheels 42 and 44, wherein the gear wheel 44 is arranged on the transmission input shaft 20, and the gear wheel 42 is arranged on the side shaft 32. The transmission input shaft 20 and the side shaft 32 are shafts of the dual clutch transmission 10, in particular of the sub-transmission 16, wherein the shafts are designed separate from one another and can be rotated relative to one another. In particular, the shafts are arranged offset with respect to one another, wherein the shafts extend at least substantially parallel to one another.

[0035] In order to be able to then implement a particularly high comfort, in particular driving comfort, of the motor vehicle, the gear wheel 38 arranged on the side shaft 32 is designed as a loose wheel which is rotatably arranged on the side shaft 32. In addition, the gear wheel 44 arranged on the transmission input shaft 20 is designed as a loose wheel which is rotatably arranged on the transmission input shaft 20. Moreover, the gear 18a is designed as the aforementioned reverse gear. Here, the gear wheel 38 does not mesh with the gear wheel 40, instead an intermediate gear wheel 46 associated with the gear wheels 38 and 40 is provided for the reversal of the direction of rotation. Here, the intermediate gear wheel 46 simultaneously meshes with the gear wheels 38 and 40.

[0036] In the present case a switching element 48, designed as shift collar or claw clutch and thus as positive-locking switching element, is associated with the gear wheel 38, designed as loose wheel, wherein said switching element is connected in a torque-proof manner to the side shaft 32 and can be switched between a first connection state shown in the FIG. and a first release state, in particular moved by translation relative to the side shaft 32. In the first release state, the switching element 48 releases the gear wheel 38 for a rotation occurring relative to the side shaft 32. However, in the first connection state, the gear wheel 38 is connected by means of the switching element 48 in a torque-proof manner to the side shaft 32, in particular by positive connection.

[0037] The gear wheel 44 also is designed as a loose wheel which is rotatably arranged on the transmission input shaft 20. The gear wheel 44 directly meshes with the gear wheel 42. In addition, a second switching element 50, designed as shift collar or claw clutch and thus designed as positive-locking switching element, is associated with the gear wheel 44, wherein said second switching element can be switched between at least one second connection state shown in the FIG. and a second release state, in particular moved by translation relative to the transmission input shaft 20. In the second release state, the switching element 50 releases the gear wheel 44 for a rotation occurring relative to the transmission input shaft 20. However, in the second connection state, the gear wheel 44 is connected in a torque-proof manner to the transmission input shaft 20 by means of the switching element 50. The feature that the gears 18a and 18c are simultaneously engaged in the parking lock state is to be understood to mean in particular that, in the parking lock state, the switching elements 48 and 50 are simultaneously in their connection states, so that the gear wheels 38 and 44 are simultaneously connected in a torque-proof manner to the side shaft 32 or to the transmission input shaft 20. In the case of the dual clutch transmission 10, a particularly quick ending of the parking lock state, that is to say a particularly quick disengagement or deactivation of the parking lock, is possible, in particular independently of whether the downhill force acts in vehicle longitudinal direction from the front to the rear or else from the rear to the front, independently of whether the driver, when starting the motor vehicle which initially is at standstill, wishes to start the motor vehicle in vehicle longitudinal direction forward or in reverse. A non-positive connection required for the starting can always be immediately implemented in such a manner that the driver can start the motor vehicle in the travel direction which they desire without an excessive delay occurring and without excessive load jolting occurring during the deactivation of the parking lock.