DRY DOUBLE CLUTCH FOR AN ELECTRIC AXLE, AND ELECTRIC AXLE COMPRISING THE DRY DOUBLE CLUTCH

Abstract

A dry double clutch for an electric axle includes a clutch unit and an actuation unit. The clutch unit has a first clutch device for connecting a drive shaft with a first output shaft, and a second clutch device, coaxial to the first clutch device, for connecting the drive shaft with a second output shaft. The actuation unit has a first actuation device for actuating the first clutch device, and a second actuation device for actuating the second clutch device. The first clutch device is closed when the first actuation device is not actuated, and the second clutch device is open when the second actuation device is not actuated. The first clutch device is arranged to be opened by a first pressure force from the first actuation device, and the second clutch device is arranged to be closed by a second pressure force from the second actuation device.

Claims

1.-10. (canceled)

11. A dry double clutch for an electric axle of a vehicle, comprising: a main axis; a clutch unit comprising: a first clutch device for connecting a drive shaft with a first output shaft; and a second clutch device for connecting the drive shaft with a second output shaft, the second clutch device arranged coaxial to the first clutch device with respect to the main axis; an actuation unit comprising: a first actuation device for actuating the first clutch device; and a second actuation device for actuating the second clutch device, wherein: the first clutch device is closed when the first actuation device is not actuated; the second clutch device is open when the second actuation device is not actuated; the first clutch device is arranged to be opened by a first pressure force from the first actuation device applied axially with respect to the main axis; and the second clutch device is arranged to be closed by a second pressure force from the second actuation device applied axially with respect to the main axis.

12. The dry double clutch of claim 11 further comprising a first spring element for applying a closing force that closes the first clutch device when the first actuation device is not actuated.

13. The dry double clutch of claim 12 wherein the first spring element acts on the first clutch device axially with respect to the main axis with a first spring force as the closing force.

14. The dry double clutch of claim 12 further comprising a first bearing device for transmitting the first pressure force, wherein the first spring element is supported on the first bearing device and on the first clutch device.

15. The dry double clutch of claim 11 further comprising a second spring element for applying an opening force that opens the second clutch device when the second actuation device is not actuated.

16. The dry double clutch of claim 15 wherein the second spring element acts on the second clutch device axially with respect to the main axis with a second spring force as the opening force.

17. The dry double clutch of claim 15 further comprising a second bearing device for transmitting the second pressure force, wherein the second spring element is supported on the second bearing device and on the second clutch device.

18. The dry double clutch of claim 11 further comprising: a first spring element for applying a closing force that closes the first clutch device when the first actuation device is not actuated; and a second spring element for applying an opening force that opens the second clutch device when the second actuation device is not actuated.

19. The dry double clutch of claim 18 wherein: the first spring element acts on the first clutch device axially with respect to the main axis with a first spring force as the closing force; and the second spring element acts on the second clutch device axially with respect to the main axis with a second spring force as the opening force.

20. The dry double clutch of claim 18 further comprising: a first bearing device for transmitting the first pressure force; and a second bearing device for transmitting the second pressure force, wherein: the first spring element is supported on the first bearing device and on the first clutch device; and the second spring element is supported on the second bearing device and on the second clutch device.

21. The dry double clutch of claim 11 further comprising a drive-side clutch section for non-rotatable connection to the drive shaft, wherein: the first clutch device comprises: a first output-side clutch section for connection to the first output shaft; and a first pressure plate; the second clutch device comprises: a second output-side clutch section for connection to the second output shaft; and a second pressure plate; the first output-side clutch section is frictionally held between the first pressure plate and the drive-side clutch section when the first clutch device is in a first clutch closed operating state; and the second output-side clutch section is frictionally held between the second pressure plate and the drive-side clutch section when the second clutch device is in a second clutch closed operating state.

22. The dry double clutch of claim 21, further comprising: a first spring element for applying a closing force that closes the first clutch device when the first actuation device is not actuated; and a second spring element for applying an opening force that opens the second clutch device when the second actuation device is not actuated, wherein: the first spring element acts on the first pressure plate with the closing force when the first actuation device is not actuated, so that the first output-side clutch section is frictionally held; and the second spring element acts on the second pressure plate with the opening force when the second actuation device is not actuated, so that the second output-side clutch section is arranged without friction with respect to the second pressure plate and the drive-side clutch section.

23. The dry double clutch of claim 21, further comprising: a first bearing device for transmitting the first pressure force; and a first spring element for applying a closing force that closes the first clutch device when the first actuation device is not actuated, wherein: the first spring element comprises: a radial inner section supported on the first bearing device; a radial outer section supported on the first pressure plate; and a radial center section supported on the drive-side clutch section via a first contact face; and the first spring element is pivotable about the first contact face when the first pressure force is applied so that the first pressure plate is relieved and the first clutch device is opened.

24. The dry double clutch of claim 21, further comprising: a second bearing device for transmitting the second pressure force; and a second spring element for applying an opening force that opens the second clutch device when the second actuation device is not actuated, wherein: the second spring element comprises: a radial inner section supported on the second bearing device; a radial outer section supported on the second pressure plate; and a radial center section supported on the drive-side clutch section via a second contact face; and the second spring element is pivotable about the second contact face when the second pressure force is applied so that the second pressure plate is loaded and the second clutch device is closed.

25. An electric axle for a vehicle comprising the dry double clutch of claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further features, advantages and effects of the disclosure are set out in the following description of example embodiments. It can be seen that:

[0031] FIG. 1 shows a schematic longitudinal section through an electrical axle with a dry double clutch as an exemplary embodiment of the invention; and

[0032] FIG. 2 shows a schematic longitudinal section through the dry double clutch of FIG. 1.

DETAILED DESCRIPTION

[0033] FIG. 1 shows, in a schematic longitudinal section, an electric axle 1 as a drive train for a vehicle, which is used to drive the vehicle. This has two output shafts 2a, 2b, which are gear-connected to driven wheels of an axle of the vehicle.

[0034] The electric axle 1 has, as the exclusive drive motor, an electric motor 3, only indicated schematically, which is arranged coaxially to a main axis H defined by the output shafts 2a, b. The output of the electric motor 3 is a rotor shaft which forms a drive shaft 4 and is arranged as a hollow shaft coaxially and concentrically with the output shaft 2a.

[0035] The electric axle 1 has a dry double clutch 5, and the drive shaft 4 forms an input of the dry double clutch 5. The dry double clutch 5 has a clutch unit 6 which includes first and a second clutch devices 7, 8. First and second output shafts 9a, 9b are provided as outputs of the dry double clutch 5, which, for example, in a subsequent transmission section 10, only indicated schematically, lead to two different gear ratios, so that the electric axle 1 has at least or exactly two gears and optionally a neutral gear as well. The dry double clutch 5, together with the following transmission section 10, thus forms a manual transmission.

[0036] The electric axle 1 has a housing 11 which encloses the electric motor 3, the dry double clutch 5 and the subsequent transmission section 10. The housing 11 has a stationary section 12 which is, for example, fixedly and/or rigidly connected to the housing 11.

[0037] The first and second clutch devices 7, 8 are each designed as a dry friction clutch and are arranged, for example, in a lubricant-free housing section of the electrical axle 1. The first clutch device 7 is implemented as a “normally closed” coupling and the second clutch device 8 is implemented as a “normally opened” coupling. In this context, “normally closed” means that the first clutch device 7 is in a closed operating state in an unactuated basic state of the dry double clutch 5. The drive shaft 4 and the first output shaft 9a are rotationally coupled to one another, so that the electric axle 1 is switched to a first gear as standard. The second clutch device 8, on the other hand, is in an unactuated basic state of the dry double clutch 5 in an open operating state, wherein “normally opened” thus means that the drive shaft 4 and the second output shaft 9b are decoupled from one another.

[0038] The dry double clutch 5 has an actuation unit 13 which enables the dry double clutch 5 to be actuated. For this purpose, the actuation unit 13 has a first actuation device 14 for actuating the first clutch device 7 and a second actuation device 15 for actuating the second clutch device 8. In the embodiment shown, the actuation unit 13 is designed hydraulically, wherein the first actuation device 14 applies a first hydraulically generated pressure force F1 to open the first clutch device 7, and a second hydraulically generated pressure force F2 on the first clutch device 7 and the second actuation device 15 to close the second clutch device 8 can be transmitted to the second clutch device 8. Thus, the first clutch device 7 can optionally be opened and/or the second clutch device 8 can be closed. The actuation unit 13 is fixedly mounted and/or supported on the section 12.

[0039] FIG. 2 shows the dry double clutch 5 in a schematic longitudinal section along the main axis H. The first and the second clutch device 7. 8 have a drive-side clutch section 16 and in each case an output-side clutch section 17a, 17b. The drive-side clutch section 16 is arranged on the side of the electric motor 3, as shown in FIG. 1, and the output-side clutch section 17a, 17b is arranged on the side of the transmission section 10, as shown in FIG. 1.

[0040] The drive-side clutch section 16 has a flywheel 18, and a central disk 19 and support housing 20 non-rotatably connected to the flywheel 18. The flywheel 18 is non-rotatably connected to the drive shaft 4 (ref. FIG. 1). The flywheel 18, the central disk 19 and the support housing 20 are connected to one another in a rotationally fixed manner radially on the outside with respect to the main axis H, and are arranged radially inwardly spaced apart from one another in the axial direction. The central disk 19 forms a first clutch surface 19a with an axial end face facing the first output-side clutch section 17a, and a second clutch surface 19b with an axial end face facing the second output-side clutch section 17b. For example, the first and/or the second clutch surface 19a, 19b can be formed by a friction lining.

[0041] The two output-side clutch sections 17a, 17b are each designed as a clutch disk. The first output-side clutch section 17a is non-rotatably connected to the first output shaft 9a (ref. FIG. 1) and the second output-side clutch section 17b is non-rotatably connected to the second output shaft 9b (ref. FIG. 1). The drive-side clutch section 16, in particular the central disk 19, can optionally be placed in connection with the first output-side clutch section 17a and/or the second drive-side clutch section 17b, so that the drive shaft 2 can be connected either to the first output shaft 9a or to the second output shaft 9b.

[0042] For this purpose, the first clutch device 7 has a first pressure plate 21a and the second clutch device 8 has a second pressure plate 21b. The two pressure plates 21a, 21b are displaceable in the axial direction with respect to the main axis, but are arranged non-rotatably around the main axis H in the direction of rotation. The first output-side clutch section 17a and the first pressure plate 21a are arranged in the axial direction with respect to the main axis H between the central disk 19 and the support housing 20. The second output-side clutch section 17b and the second pressure plate 21b are arranged in the axial direction with respect to the main axis H between the flywheel 18 and the central disk 19. For example, the first and/or the second pressure plate 21a, 21b can have a further friction lining. Alternatively or optionally in addition, the two clutch disks can have friction linings.

[0043] The first pressure force F1 is transmitted via a first bearing device 22, and the second pressure force F2 via a second bearing device 23 in an axial direction with respect to the main axis H. Furthermore, the first actuation device 14 has a first actuating member 24a and the second actuation device 15 has a second actuating member 24b. The two actuating members 24a, 24b are each designed as a hydraulic cylinder, which enables a stroke in the axial direction to the main axis H. The first actuating member 24a actuates the first clutch device 7 via the first bearing device 22, and the second actuating member 24b actuates the second clutch device 8 via the second bearing device 23, and either one or both clutch devices 7, 8 can be actuated. The two actuating members 24a, 24b are designed as ring cylinders coaxial to the main axis H. The two bearing devices 22, 23 also run coaxially around the main axis H.

[0044] The dry double clutch 5 has a first and a second spring element 25a, 25b, and the two spring elements 25a, 25b are each designed as a disk spring and arranged coaxially to the main axis H. The first spring element 25a is supported with a radial outer section in the axial direction with respect to the main axis H on the first pressure plate 21a, and with a radial inner section in an axially opposite direction on an inner ring of the first bearing device 22. In this case, the first spring element 25a applies a closing force F3 on the first pressure plate 21a in an unactuated state of the first actuation device 14 in the axial direction with respect to the main axis H. The first output-side clutch section 17a, designed as a clutch disk, is thus frictionally held between the first clutch surface 19a and the first pressure plate 21a and the first clutch device 7 is switched to a closed operating state.

[0045] The second clutch device 8 has a transmission section 26. The transmission section 26 is mounted on the second pressure plate 21b and extends in the direction of the actuating unit 13 such that the second spring element 25b is arranged on a common side with the first spring element 25b, and these can be actuated on one side by the actuation unit 13. The second spring element 25b is supported with a radial outer section with respect to the main axis H in the axially opposite direction on the transmission section 26, and with a radial inner section on an inner ring of the second bearing device 23. In this case, the second spring element 25b applies an opening force F4 on the second pressure plate 21b via the transmission section 26 in an unactuated state of the second actuation device 15 in the axial direction with respect to the main axis H. Thus, the second output-side clutch section 17b, designed as a clutch disk, is arranged without contact or at least unloaded between the second clutch surface 19b and the second pressure plate 21b, and the second clutch device 8 is switched to an open operating state.

[0046] When the first actuation device 14 is actuated, the first pressure force F1 is transmitted via the first bearing device 22 to the first spring element 25a, so that the first spring element 25a is deformed and the first clutch device 7 is opened. For this purpose, the first spring element 25a is pivotably mounted via a contact face 20a on the output-side clutch section 16, in particular the support housing 20, so that, when the first pressure force F1 is applied, the first spring element 25a is pivoted about the support 20a and the first pressure plate 21a is relieved or moved away from the second output-side clutch section 17a. In an actuated state of the first actuation device 14, the two clutch devices 7, 8 are therefore in an open operating state, so that the electric axle 1 is shifted into a neutral gear.

[0047] When the second actuation device 15 is actuated, the second pressure force F2 is transmitted via the second bearing device 23 to the second spring element 25b, so that the second spring element 25b is deformed and the second clutch device 8 is opened. For this purpose, the second spring element 25b is pivotably mounted via a contact face 20b on the output-side clutch section 16, in particular the support housing 20, so that, when the second pressure force F2 is applied, the second spring element 25b is pivoted about the support 20b and the second pressure plate 21b is relieved or moved towards the second output-side clutch section 17b.

[0048] The support housing 20 is designed in such a way that the contact face 20a is arranged on a side facing the first clutch device 7 and the further contact face 20b is arranged on a side facing away from the first clutch device 7. The support housing 20 is thus arranged in the axial direction with respect to the main axis H between the two spring elements 25a, 25b, and the two spring elements 25a, 25b are supported jointly on the support housing 20. In the exemplary embodiment shown, the transmission section 26 is axially guided and/or displaceably supported by the drive-side clutch section 16.

[0049] When driving in second gear, both actuation devices must be operated in 14, 15. The two actuation devices 14, 15 can be actuated at the same time or at different times. In an actuated state of the first and second actuation devices 14, 15, the first clutch device 7 is in an open operating state and the second clutch device 8 is in a closed operating state, so that the electric axle 1 is shifted to a second gear.

[0050] Furthermore, the first actuation device 14 has a first preload spring 27a and the second actuation device 15 has a second preload spring 27b. The first preload spring 27a acts on the first actuating member 24a and the second preload spring 27b acts on the second actuating element 24b in the axial direction with respect to the main axis H, in each case with a preload.

[0051] The exemplary embodiment shown represents the operating state of the electric axle 1, which is driven in first gear. The load on the first bearing device 22 is lower and the time components are reduced, since only the preload acts on the first bearing device 22 over large parts of the journey. In addition, due to the lever ratio between the first bearing device 22 and the clutch disk, the force on the first bearing device 22 can be reduced (depending on the ratio), so that the first bearing device 22 as a whole can thus be made smaller.

[0052] For the electric axle 1, in which the vehicle is driven completely electrically, no clutch is required for start-up. In other words, when starting up, the first clutch device 7 is already closed. In addition, it is possible to drive in one gear for a relatively long time, wherein, for example, only the first gear is used when driving around town, while second gear is used for driving at high speeds on the motorway. Usually, large load shares in the load spectrum for the bearings are on the first clutch device 7. However, if the first clutch device 7 is closed as standard and is only opened when shifting into second gear, the ratio of the load components rotates and the bearing device 22 can be dimensioned smaller, thereby minimizing power loss. Because of the high rotational speeds in the electrical axle 1, the bearing devices 22, 23 can become very hot, wherein the grease is not able to withstand this temperature and the bearing devices 22, 23 can become damaged. Due to the reduced load spectrum, a dry double clutch is proposed, for use in the electric axle 1.

REFERENCE NUMERALS

[0053] 1 Electric axle

[0054] 2a, 2b Output shafts

[0055] 3 Electrometer

[0056] 4 Drive shaft

[0057] 5 Dry clutch

[0058] 6 Clutch unit

[0059] 7 First clutch device

[0060] 8 Second clutch device

[0061] 9a, 9b Output shafts

[0062] 10 Transmission section

[0063] 11 Housing

[0064] 12 Stationary section

[0065] 13 Actuation unit

[0066] 14 First actuation device

[0067] 15 Second actuation device

[0068] 16 Drive-side clutch section

[0069] 17a, 17b Output-side clutch sections

[0070] 18 Flywheel

[0071] 19 Central disk

[0072] 20 Support housing

[0073] 20a, 20b Contact face

[0074] 21a, 21b Pressure plates

[0075] 22 First bearing device

[0076] 23 Second bearing device

[0077] 24a, 24b Actuating members

[0078] 25a, 25b Spring elements (plate springs)

[0079] 26 Transmission section

[0080] 27a, 27b Preload springs

[0081] F1 First pressure force

[0082] F2 Second pressure force

[0083] F3 Closing force

[0084] F4 Opening force

[0085] H Main axis